FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Ashurst, WT Holian, BL AF Ashurst, WT Holian, BL TI Droplet formation by rapid expansion of a liquid SO PHYSICAL REVIEW E LA English DT Article ID LENNARD-JONES FLUIDS; MOLECULAR-DYNAMICS; LARGE-SCALE; FRAGMENTATION; STATISTICS AB Molecular dynamics of two- and three-dimensional liquids undergoing a homogeneous adiabatic expansion provides a direct numerical simulation of the atomization process. The Lennard-Jones potential is used with different force cutoff distances; the cluster distributions do not depend strongly on the cutoff parameter. Expansion rates, scaled by the natural molecular time unit (about a picosecond), are investigated from unity down to 0.01; over this range the mean droplet size follows the scaling behavior of an energy balance model which minimizes the sum of kinetic plus surface energy. A second model which equates the elastic stored energy to the surface energy gives better agreement with the simulation results. The simulation results indicate that both the mean and the maximum droplet size have a power-law dependence upon the expansion rate; the exponents are - 2d/3 (mean) and - d/2 (maximum), where d is the dimensionality. The mean does not show a dependence upon the system size, whereas the maximum does increase with system size, anti furthermore, its exponent increases with an increase in the force cutoff distance, A mean droplet size of 2.8/eta(2), where eta is the expansion rate, describes our high-density three-dimensional simulation results, and this relation is also close to experimental results from the free-jet expansion of liquid helium. Thus. one relation spans a cluster size range from one atom to over 40 million atoms. The structure and temperature of the atomic clusters are described. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Ashurst, WT (reprint author), Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. NR 15 TC 46 Z9 47 U1 0 U2 7 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD JUN PY 1999 VL 59 IS 6 BP 6742 EP 6752 DI 10.1103/PhysRevE.59.6742 PG 11 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 210YY UT WOS:000081134200065 PM 11969662 ER PT J AU Ben-Naim, E Lapedes, AS AF Ben-Naim, E Lapedes, AS TI Genetic correlations in mutation processes SO PHYSICAL REVIEW E LA English DT Article ID PROTEIN AB We study the role of phylogenetic trees on correlations in mutation processes. Generally, correlations decay exponentially with the generation number. We find that two distinct regimes of behavior exist. For mutation rates smaller than a critical rate, the underlying tree morphology is almost irrelevant, while mutation rates higher than this critical rate lead to strong tree-dependent correlations. We show analytically that identical critical behavior underlies all multiple point correlations. This behavior generally characterizes branching processes undergoing mutation. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. RP Ben-Naim, E (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RI Ben-Naim, Eli/C-7542-2009 OI Ben-Naim, Eli/0000-0002-2444-7304 NR 11 TC 2 Z9 2 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD JUN PY 1999 VL 59 IS 6 BP 7000 EP 7007 DI 10.1103/PhysRevE.59.7000 PG 8 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 210YY UT WOS:000081134200091 PM 11969688 ER PT J AU Ma, R Ellis, KJ Yasumura, S Shypailo, RJ Pierson, RN AF Ma, R Ellis, KJ Yasumura, S Shypailo, RJ Pierson, RN TI Total body-calcium measurements: comparison of two delayed-gamma neutron activation facilities SO PHYSICS IN MEDICINE AND BIOLOGY LA English DT Article ID X-RAY ABSORPTIOMETRY; CALIBRATION; OSTEOPOROSIS; THERAPY; DESIGN; WOMEN; MASS AB This study compares two independently calibrated delayed-gamma neutron activation (DGNA) facilities, one at the Brookhaven National Laboratory (BNL), Upton, New York, and the other at the Children's Nutrition Research Center (CNRC), Houston, Texas that measure total body calcium (TBCa). A set of BNL phantoms was sent to CNRC for neutron activation analysis, and a set of CNRC phantoms was measured at BNL. Both facilities showed high precision (< 2%), and the results were in good agreement, within 5%. C1 Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. Baylor Coll Med, CNRC Body Composit Lab, Houston, TX 77030 USA. St Lukes Roosevelt Hosp, Body Composit Unit, New York, NY 10025 USA. RP Ma, R (reprint author), Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. EM ma2@bnl.gov FU NIDDK NIH HHS [1 PO1-DK 42618] NR 21 TC 7 Z9 7 U1 1 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0031-9155 J9 PHYS MED BIOL JI Phys. Med. Biol. PD JUN PY 1999 VL 44 IS 6 BP N113 EP N118 DI 10.1088/0031-9155/44/6/406 PG 6 WC Engineering, Biomedical; Radiology, Nuclear Medicine & Medical Imaging SC Engineering; Radiology, Nuclear Medicine & Medical Imaging GA 204FA UT WOS:000080752400015 PM 10498507 ER PT J AU Tang, XZ Boozer, AH AF Tang, XZ Boozer, AH TI A Lagrangian analysis of advection-diffusion equation for a three dimensional chaotic flow SO PHYSICS OF FLUIDS LA English DT Article ID PASSIVE SCALARS; HAMILTONIAN-SYSTEMS; PRESERVING MAPS; TRANSPORT; FLUID; CONVECTION AB The advection-diffusion equation is studied via a global Lagrangian coordinate transformation. The metric tensor of the Lagrangian coordinates couples the dynamical system theory rigorously into the solution of this class of partial differential equations. If the flow has chaotic streamlines, the diffusion will dominate the solution at a critical time, which scales logarithmically with the diffusivity. The subsequent rapid diffusive relaxation is completed on the order of a few Lyapunov times, and it becomes more anisotropic the smaller the diffusivity. The local Lyapunov time of the flow is the inverse of the finite time Lyapunov exponent. A finite time Lyapunov exponent can be expressed in terms of two convergence functions which are responsible for the spatio-temporal complexity of both the advective and diffusive transports. This complexity gives a new class of diffusion barrier in the chaotic region and a fractal-like behavior in both space and time. In an integrable flow with shear, there also exist fast and slow diffusion. But unlike that in a chaotic flow, a large gradient of the scalar field across the KAM surfaces can be maintained since the fast diffusion in an integrable flow is strictly confined within the KAM surfaces. (C) 1999 American Institute of Physics. [S1070-6631(99)02106-6]. C1 Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. Columbia Univ, Dept Appl Phys, New York, NY 10027 USA. EURATOM, Max Planck Inst Plasmaphys, D-85748 Garching, Germany. RP Tang, XZ (reprint author), Princeton Univ, Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. EM xtang@pppl.gov NR 37 TC 21 Z9 21 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD JUN PY 1999 VL 11 IS 6 BP 1418 EP 1434 DI 10.1063/1.870006 PG 17 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 197UL UT WOS:000080384000015 ER PT J AU Petrov, MP Bell, R Budny, RV Gorelenkov, NN Medley, SS White, RB Zweben, SJ AF Petrov, MP Bell, R Budny, RV Gorelenkov, NN Medley, SS White, RB Zweben, SJ TI Effective temperatures, sawtooth mixing, and stochastic diffusion ripple loss of fast H+ minority ions driven by ion cyclotron heating in the Tokamak Fusion Test Reactor SO PHYSICS OF PLASMAS LA English DT Article ID DEUTERIUM-TRITIUM PLASMAS; CONFINED ALPHAS; TFTR; JET; NEUTRALIZATION; BEHAVIOR; CRASHES; TRITONS; ICRF; BEAM AB This paper presents studies of the H+ minority ions driven by Ion Cyclotron Radio Frequency (ICRF) heating in the Tokamak Fusion Test Reactor (TFTR) [R.J. Hawryluk et al., Phys. Plasmas 5, 1577 (1998)] deuterium plasmas using primarily passive H degrees flux detection in the energy range of 0.2-1.0 MeV. The measured passive H+ energy spectra are compared with active (Li pellet charge exchange) results. It is shown that in the passive mode the main donors for the neutralization of H+ ions in this energy range are C5+ ions. The measured effective H+ tail temperatures range from 0.15 MeV at an ICRF power of 2 MW to 0.35 MeV at 6 MW. Radial redistribution of ICRF-driven H+ ions was detected when giant sawtooth crashes occurred during the ICRF heating. The redistribution affected ions with energy below 0.7-0.8 MeV. The sawtooth crashes displaces H+ ions outward along the plasma major radius into the stochastic ripple diffusion domain where those ions are lost in similar to 10 msec. These observations are consistent with the model of the redistribution of energetic particles developed previously to explain the results of deuterium-tritium (DT) alpha-particle redistribution due to sawtooth oscillations observed in TFTR. The experimental data are also consistent with numerical simulations of H+ stochastic ripple diffusion losses. (C) 1999 American Institute of Physics. C1 Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. AF Ioffe Phys Tech Inst, St Petersburg 194021, Russia. TRINITI, Troitsk 142092, Russia. RP Petrov, MP (reprint author), Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. RI White, Roscoe/D-1773-2013 OI White, Roscoe/0000-0002-4239-2685 NR 25 TC 13 Z9 13 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD JUN PY 1999 VL 6 IS 6 BP 2430 EP 2436 DI 10.1063/1.873539 PG 7 WC Physics, Fluids & Plasmas SC Physics GA 197EE UT WOS:000080351000014 ER PT J AU Ohno, N Tanaka, M Ezumi, N Nishijima, D Takamura, S Krasheninnikov, SI Pigarov, AY Park, J AF Ohno, N Tanaka, M Ezumi, N Nishijima, D Takamura, S Krasheninnikov, SI Pigarov, AY Park, J TI Dynamic response of detached recombining plasmas to plasma heat pulse in a divertor simulator SO PHYSICS OF PLASMAS LA English DT Article ID DIII-D; GAS-TARGET; DISCHARGES; RADIATION AB The experiments on the plasma heat pulse to the detached recombining helium plasma associated with the volumetric radiative and three-body recombination (EIR) have been performed in a linear divertor plasma simulator. Detailed observations of the time evolution of plasma parameters and helium Balmer series spectra show that the dynamic response of the detached recombining plasma to the heat pulse depends strongly on the heat transport through energetic electrons generated by the heat pulse. For the detached recombining plasma with a relatively low neutral pressure, it was found that the EIR is not sufficient to suppress an increase of ion flux to the target plate during the pulse. Several key characteristic time scales involved in this system are also analyzed. (C) 1999 American Institute of Physics. [S1070-664X(99)01606-7]. C1 Nagoya Univ, Grad Sch Engn, Dept Energy Engn & Sci, Nagoya, Aichi 4648603, Japan. MIT, Plasma Sci & Fus Ctr, Cambridge, MA 02139 USA. Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Nagoya Univ, Grad Sch Engn, Dept Energy Engn & Sci, Nagoya, Aichi 4648603, Japan. EM ohno@nuee.nagoya-u.ac.jp NR 28 TC 16 Z9 16 U1 1 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 1070-664X EI 1089-7674 J9 PHYS PLASMAS JI Phys. Plasmas PD JUN PY 1999 VL 6 IS 6 BP 2486 EP 2494 DI 10.1063/1.873520 PG 9 WC Physics, Fluids & Plasmas SC Physics GA 197EE UT WOS:000080351000020 ER PT J AU Johnson, JL Ichiguchi, K Nakamura, Y Okamoto, M Wakatani, M Nakajima, N AF Johnson, JL Ichiguchi, K Nakamura, Y Okamoto, M Wakatani, M Nakajima, N TI External kink modes in a Large Helical Device (LHD) equilibrium with self-consistent bootstrap current SO PHYSICS OF PLASMAS LA English DT Article ID NET TOROIDAL CURRENT; MHD INSTABILITIES; FREE-BOUNDARY; STABILITY; PLASMAS; STELLARATORS; TORSATRON; SYSTEM AB Magnetohydrodynamic (MHD) stability studies of low- mode-number free-boundary kink modes in a finite-beta Large Helical Device (LHD) [A. Ilyoshi, et al. Fusion Technology 17, 169 (1990)] equilibrium series with self-consistent bootstrap current find some serious free-boundary modes. They indicate that care must be taken in the design of high-beta experiments. Since the LHD configuration is flexible, with the possibility of introducing or modifying dipole and quadrapole fields, unbalancing the currents in the helical coils, operating with a high-temperature divertor, and changing the collisionality regime by working with different values of temperature and density, paths to high-beta operation should exist. Comparison of the experimental results with these theoretical predictions for the studied equilibrium sequence will provide understanding of the MHD stability properties of LHD. (C) 1999 American Institute of Physics. [S1070-664X(99)03206-1]. C1 Natl Inst Fus Sci, Toki 509, Japan. Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. Natl Inst Fus Sci, Toki 5095292, Japan. Kyoto Univ, Grad Sch Energy Sci, Uji, Kyoto 6110011, Japan. RP Natl Inst Fus Sci, Oroshi cho 322-6, Toki 509, Japan. NR 39 TC 14 Z9 14 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 1070-664X EI 1089-7674 J9 PHYS PLASMAS JI Phys. Plasmas PD JUN PY 1999 VL 6 IS 6 BP 2513 EP 2522 DI 10.1063/1.873523 PG 10 WC Physics, Fluids & Plasmas SC Physics GA 197EE UT WOS:000080351000023 ER PT J AU Qin, H Tang, WM Rewoldt, G AF Qin, H Tang, WM Rewoldt, G TI Linear gyrokinetic theory for kinetic magnetohydrodynamic eigenmodes in tokamak plasmas SO PHYSICS OF PLASMAS LA English DT Article ID INTERNAL KINK MODES; TOROIDAL ALFVEN EIGENMODES; BALLOONING MODES; HIGH-BETA; ELECTROMAGNETIC MODES; EQUATIONS; SHEAR; INSTABILITY; EXCITATION; EQUILIBRIA AB A two-dimensional (2D) numerical solution method is developed for the recently derived linear gyrokinetic system which describes arbitrary wavelength electromagnetic perturbations in tokamak plasmas. The system consists of the gyrokinetic equation, the gyrokinetic Poisson equation, and the gyrokinetic moment equation. Since familiar magnetohydrodynamic (MHD) results can be recovered entirely from this gyrokinetic model, and all interesting kinetic effects are intrinsically included, this gyrokinetic system offers an approach for kinetic MHD phenomena which is more rigorous, self-consistent, and comprehensive than the previous hybrid models. Meanwhile, drift type microinstabilities can be also investigated systematically in this theoretical framework. The linear gyrokinetic equation is solved for the distribution function in terms of the perturbed fields by integrating along unperturbed particle orbits. The solution is substituted back into the gyrokinetic moment equation and the gyrokinetic Poisson equation. When the boundary conditions are incorporated, an eigenvalue problem is formed. The resulting numerical code, KIN-2DEM, is applied to kinetic ballooning modes, internal kink modes, and toroidal Alfven eigenmodes (TAEs). The numerical results are benchmarked against the well-established FULL code [G. Rewoldt, W. M. Tang, and M. S. Chance, Phys. Fluids 25, 480 (1982)], the PEST code [J. Manickam, Nucl. Fusion 24, 595 (1984)], and the NOVA-K code [C. Z. Cheng, Phys. Rep. 211, No. 1 (1992)]. More importantly, kinetic effects on MHD modes can be investigated nonperturbatively. In particular, the kinetic effects of the background plasma on internal kink modes and the hot particle destabilization of TAEs are studied numerically. (C) 1999 American Institute of Physics. [S1070-664X(99)03806-9]. C1 Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Qin, H (reprint author), Princeton Univ, Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 70 TC 34 Z9 34 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD JUN PY 1999 VL 6 IS 6 BP 2544 EP 2562 DI 10.1063/1.873526 PG 19 WC Physics, Fluids & Plasmas SC Physics GA 197EE UT WOS:000080351000026 ER PT J AU Gary, SP Skoug, RM Daughton, W AF Gary, SP Skoug, RM Daughton, W TI Electron heat flux constraints in the solar wind SO PHYSICS OF PLASMAS LA English DT Article ID ULYSSES OBSERVATIONS; PROTON TEMPERATURE; DISTRIBUTIONS; INSTABILITY; MODEL; WAVES; 1-AU AB Enhanced fluctuations from electromagnetic heat flux instabilities may, through wave-particle scattering, constrain the electron heat flux which flows parallel to the background magnetic field in the solar wind. A corollary of this hypothesis is that instability thresholds should correspond to observable bounds on the heat flux. Here plasma and magnetic field data from February and March 1995 of the Ulysses mission is analyzed in terms of the core/halo electron model to yield scaling relations of dimensionless electron parameters and empirical upper bounds on the dimensionless heat flux as functions of the core beta. Use of these scaling relations in linear Vlasov theory for the whistler and Alfven heat flux instabilities in homogeneous plasmas yields threshold conditions on the dimensionless heat flux which are also functions of the electron core beta. The empirical bounds and the theoretical thresholds are similar and are therefore consistent with the hypothesis. (C) 1999 American Institute of Physics. [S1070-664X(99)03706-4]. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Los Alamos Natl Lab, Los Alamos, NM 87545 USA. EM pgary@lanl.gov RI Daughton, William/L-9661-2013 NR 26 TC 13 Z9 13 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 1070-664X EI 1089-7674 J9 PHYS PLASMAS JI Phys. Plasmas PD JUN PY 1999 VL 6 IS 6 BP 2607 EP 2612 DI 10.1063/1.873532 PG 6 WC Physics, Fluids & Plasmas SC Physics GA 197EE UT WOS:000080351000032 ER PT J AU Leach, RR Dowla, FU Schultz, CA AF Leach, RR Dowla, FU Schultz, CA TI Optimal filter parameters for low SNR seismograms as a function of station and event location SO PHYSICS OF THE EARTH AND PLANETARY INTERIORS LA English DT Article; Proceedings Paper CT 29th General Assembly of the International-Association-of-Seismology-and-Physics-of-the-Earths-Interi or CY AUG 18-28, 1997 CL THESSALONIKI, GREECE SP Int Assoc Seismol & Phys Earths Interior DE constant Q filter banks; wavelet transform; calibrated seismic events; Middle East; scales; signal-to-noise; receiver operating characteristics ID WAVELET TRANSFORM AB Global seismic monitoring requires deployment of seismic sensors worldwide, in many areas that have not been studied or have few useable recordings. Using events with lower signal-to-noise ratios (SNR) would increase the amount of data from these regions. Lower SNR events can add significant numbers to data sets, but recordings of these events must be carefully filtered. For a given region, conventional methods of filter selection can be quite subjective and may require intensive analysis of many events. To reduce this laborious process, we have developed an automated method to provide optimal filters for low SNR regional or teleseismic events. As seismic signals an often localized in frequency and time with distinct time-frequency characteristics, our method is based on the decomposition of a time series into a set of subsignals, each representing a band with f/Delta f constant (constant Q). The SNR is calculated on the pre-event noise and signal window. The band pass signals with high SNR are used to indicate the cutoff filter limits for the optimized filter. Results indicate a significant improvement in SNR, particularly for low SNR events. The method provides an optimum filter which can be immediately applied to unknown regions. The filtered signals are used to map the seismic frequency response of a region and may provide improvements in travel-time picking, azimuth estimation, regional characterization, and event detection. For example, when an event is detected and a preliminary location is determined, the computer could automatically select optimal filter bands for data from non-reporting stations. Results are shown for a set of low SNR events as well as 379 regional and teleseismic events recorded at stations ABKT, KIV, and ANTO in the Middle East. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Lawrence Livermore Natl Lab, Div Earth Sci, Livermore, CA 94550 USA. RP Leach, RR (reprint author), Lawrence Livermore Natl Lab, Div Earth Sci, 7000 E Ave L-208, Livermore, CA 94550 USA. EM leach1@llnl.gov; dowla1@llnl.gov; shultz9@llnl.gov NR 17 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0031-9201 J9 PHYS EARTH PLANET IN JI Phys. Earth Planet. Inter. PD JUN PY 1999 VL 113 IS 1-4 SI SI BP 213 EP 226 DI 10.1016/S0031-9201(99)00006-0 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 209TG UT WOS:000081064500017 ER PT J AU Schultz, CA Myers, SC Hipp, J Young, CJ AF Schultz, CA Myers, SC Hipp, J Young, CJ TI Nonstationary Bayesian kriging: a predictive technique to generate spatial corrections for seismic detection, location and identification SO PHYSICS OF THE EARTH AND PLANETARY INTERIORS LA English DT Article; Proceedings Paper CT 29th General Assembly of the International-Association-of-Seismology-and-Physics-of-the-Earths-Interi or CY AUG 18-28, 1997 CL THESSALONIKI, GREECE SP Int Assoc Seismol & Phys Earths Interior DE Bayesian kriging; geophysical corrections; seismic events AB Seismic characterization works to improve the detection, location and identification of seismic events by correcting for inaccuracies in geophysical models. These inaccuracies are caused by inherent averaging in the model and, as a result, exact data values cannot be directly recovered at a point in the model. Seismic characterization involves cataloging reference events so that inaccuracies in the model can be mapped at these points and true data values can be retained through a correction. Application of these corrections to a new event requires the accurate prediction of the correction value at a point that is near, but not necessarily coincident with the reference events. Given that these reference events can be sparsely distributed geographically, both interpolation and extrapolation of corrections to the new point are required. In this study, we develop a closed form representation of Bayesian kriging (linear prediction) that incorporates variable spatial damping. The result is a robust nonstationary algorithm for spatially interpolating geophysical corrections. This algorithm extends local trends when data coverage is good and allows for damping (blending) to an a priori background mean when data coverage is poor. Benchmark tests show that the technique gives reliable predictions of the correction value along with an appropriate uncertainty estimate. Tests with travel-time residual data demonstrate that combining variable damping with an azimuthal coverage criterion reduces the large errors that occur with more classical linear prediction techniques, especially when values an extrapolated in poor coverage regions. In the travel-time correction case, this technique generates both seismic corrections along with uncertainties and can properly incorporate model error in the final location estimate. Results favor the applicability of this nonstationary algorithm to other types of seismic corrections such as amplitude and attenuation measures. Since this studies original publication, several studies have demonstrated that nonstationary Bayesian kriging provides significant improvement over more conventional correction techniques. Applications have been performed in location and identification and each has demonstrated that this technique can combine the best theoretical earth models with empirical corrections to obtain a more accurate solution. These results and their broad implications for the future calibration of monitoring networks are discussed in a new section that follows the conclusions, (C) 1999 Seism. Sec. Am. Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Schultz, CA (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94551 USA. RI Myers, Stephen/K-1368-2014 OI Myers, Stephen/0000-0002-0315-5599 NR 21 TC 1 Z9 1 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0031-9201 J9 PHYS EARTH PLANET IN JI Phys. Earth Planet. Inter. PD JUN PY 1999 VL 113 IS 1-4 SI SI BP 321 EP 338 DI 10.1016/S0031-9201(99)00056-4 PG 18 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 209TG UT WOS:000081064500024 ER PT J AU Drake, BG Azcon-Bieto, J Berry, J Bunce, J Dijkstra, P Farrar, J Gifford, RM Gonzalez-Meler, MA Koch, G Lambers, H Siedow, J Wullschleger, S AF Drake, BG Azcon-Bieto, J Berry, J Bunce, J Dijkstra, P Farrar, J Gifford, RM Gonzalez-Meler, MA Koch, G Lambers, H Siedow, J Wullschleger, S TI Does elevated atmospheric CO2 concentration inhibit mitochondrial respiration in green plants? SO PLANT CELL AND ENVIRONMENT LA English DT Article; Proceedings Paper CT Smithsonian Environmental Research Center Workshop CY JAN 08-09, 1998 CL EDGEWATER, MARYLAND DE acclimation to rising CO2; dark respiration; global carbon cycle; rising CO2 ID CARBON-DIOXIDE CONCENTRATION; DARK RESPIRATION; MAINTENANCE RESPIRATION; CHEMICAL-COMPOSITION; CONSTRUCTION COSTS; LEAF RESPIRATION; LOLIUM-PERENNE; WHEAT LEAVES; GAS-EXCHANGE; GROWTH AB There is abundant evidence that a reduction in mitochondrial respiration of plants occurs when atmospheric CO2 (C-a) is increased. Recent reviews suggest that doubling the present C-a will reduce the respiration rate [per unit dry weight (DW)] by 15 to 18%. The effect has two components: an immediate, reversible effect observed in leaves, stems, and roots of plants as well as soil microbes, and an irreversible effect which occurs as a consequence of growth in elevated C-a and appears to be specific to C-3 species. The direct effect has been correlated with inhibition of certain respiratory enzymes, namely cytochrome-c-oxidase and succinate dehydrogenase, and the indirect or acclimation effect may be related to changes in tissue composition. Although no satisfactory mechanisms to explain these effects have been demonstrated, plausible mechanisms have been proposed and await experimental testing. These are carbamylation of proteins and direct inhibition of enzymes of respiration. A reduction of foliar respiration of 15% by doubling present ambient C-a would represent 3 Gt of carbon per annum in the global carbon budget. C1 Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. Univ Barcelona, Fac Biol, Dept Biol Vegetal, E-08028 Barcelona, Spain. Carnegie Inst Washington, Dept Plant Biol, Stanford, CA 94305 USA. ARS, USDA, Climate Stress Lab, Beltsville, MD 20705 USA. Univ Coll N Wales, Sch Biol Sci, Bangor LL57 2UW, Gwynedd, Wales. CSIRO, Canberra, ACT 2601, Australia. Duke Univ, Dept Bot, Dev Cell & Mol Biol Grp, Durham, NC 27708 USA. No Arizona Univ, Dept Biol Sci, Flagstaff, AZ 86011 USA. Univ Utrecht, Dept Plant Ecol & Evolut Biol, NL-3584 CA Utrecht, Netherlands. Duke Univ, Durham, NC USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Drake, BG (reprint author), Smithsonian Environm Res Ctr, POB 28, Edgewater, MD 21037 USA. RI Berry, Joseph/B-8211-2009; Wullschleger, Stan/B-8297-2012; Lambers, Hans/A-1544-2008; OI Berry, Joseph/0000-0002-5849-6438; Wullschleger, Stan/0000-0002-9869-0446; Lambers, Hans/0000-0002-4118-2272; Gonzalez-Meler, Miquel/0000-0001-5388-7969 NR 65 TC 105 Z9 115 U1 1 U2 20 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0140-7791 J9 PLANT CELL ENVIRON JI Plant Cell Environ. PD JUN PY 1999 VL 22 IS 6 BP 649 EP 657 DI 10.1046/j.1365-3040.1999.00438.x PG 9 WC Plant Sciences SC Plant Sciences GA 217VW UT WOS:000081520500007 ER PT J AU Norby, RJ Wullschleger, SD Gunderson, CA Johnson, DW Ceulemans, R AF Norby, RJ Wullschleger, SD Gunderson, CA Johnson, DW Ceulemans, R TI Tree responses to rising CO2 in field experiments: implications for the future forest SO PLANT CELL AND ENVIRONMENT LA English DT Review DE atmospheric carbon dioxide; forests; global change; open-top chambers; trees ID ELEVATED ATMOSPHERIC CO2; SOUR ORANGE TREES; CARBON-DIOXIDE CONCENTRATION; LIRIODENDRON-TULIPIFERA L; PONDEROSA PINE-SEEDLINGS; SPRUCE MODEL-ECOSYSTEMS; NET PRIMARY PRODUCTION; GLOBAL CLIMATE MODEL; SOIL N-AVAILABILITY; LONG-TERM ELEVATION AB The need to assess the role of forests in the global cycling of carbon and how that role will change as the atmospheric concentration of CO2 increases has spawned many experiments over a range of scales. Experiments using open-top chambers have been established at many sites to test whether the short-term responses of tree seedlings described in controlled environments would be sustained over several growing seasons under field conditions. Here we review the results of those experiments, using the framework of the interacting cycles of carbon, water and nutrients, because that is the framework of the ecosystem models that are being used to address the decades-long response of forests. Our analysis suggests that most of what was learned in seedling studies was qualitatively correct, The evidence from field-grown trees suggests a continued and consistent stimulation of photosynthesis of about 60% for a 300 p.p.m, increase in [CO2], and there is little evidence of the long-term loss of sensitivity to CO2 that was suggested by earlier experiments with tree seedlings in pots. Despite the importance of respiration to a tree's carbon budget, no strong scientific consensus has yet emerged concerning the potential direct or acclimation response of woody plant respiration to CO2 enrichment. The relative effect of CO2 on above-ground dry mass was highly variable and greater than that indicated by most syntheses of seedling studies. Effects of CO2 concentration on static measures of response are confounded with the acceleration of ontogeny observed in elevated CO2. The trees in these open-top chamber experiments were in an exponential growth phase, and the large growth responses to elevated CO2 resulted from the compound interest associated with an increasing leaf area. This effect cannot be expected to persist in a closed-canopy forest where growth potential is constrained by a steady-state leaf area index, A more robust and informative measure of tree growth in these experiments is the annual increment in wood mass per unit leaf area, which increased 27% in elevated CO2. There is no support for the conclusion from many studies of seedlings that root-to-shoot ratio is increased by elevated CO2; the production of fine roots may be enhanced, but it is not clear that this response would persist in a forest. Foliar nitrogen concentrations were lower in CO2-enriched trees, but to a lesser extent than was indicated in seedling studies and only when expressed on a leaf mass basis, The prediction that leaf litter C/N ratio would increase was not supported in field experiments. Also contrasting with seedling studies, there is little evidence from the field studies that stomatal conductance is consistently affected by CO2; however, this is a topic that demands more study. Experiments with trees in open-top chambers under field conditions have provided data on longer-term, larger-scale responses of trees to elevated CO2 under field conditions, confirmed some of the conclusions from previous seedling studies, and challenged other conclusions. There remain important obstacles to using these experimental results to predict forest responses to rising CO2, but the studies are valuable nonetheless for guiding ecosystem model development and revealing the critical questions that must be addressed in new larger-scale CO2 experiments. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Univ Antwerpen UIA, Dept Biol, B-2610 Wilrijk, Belgium. Univ Nevada, Desert Res Inst, Reno, NV 89506 USA. RP Norby, RJ (reprint author), Oak Ridge Natl Lab, Div Environm Sci, Bldg 1059,POB 2008, Oak Ridge, TN 37831 USA. RI Wullschleger, Stan/B-8297-2012; Norby, Richard/C-1773-2012; Ceulemans, Reinhart/F-2109-2016 OI Wullschleger, Stan/0000-0002-9869-0446; Norby, Richard/0000-0002-0238-9828; NR 170 TC 531 Z9 575 U1 10 U2 141 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0140-7791 J9 PLANT CELL ENVIRON JI Plant Cell Environ. PD JUN PY 1999 VL 22 IS 6 BP 683 EP 714 DI 10.1046/j.1365-3040.1999.00391.x PG 32 WC Plant Sciences SC Plant Sciences GA 217VW UT WOS:000081520500009 ER PT J AU Stratton, BC Knight, R Mikkelsen, DR Blutke, A Vavruska, J AF Stratton, BC Knight, R Mikkelsen, DR Blutke, A Vavruska, J TI Synthesis of ozone at atmospheric pressure by a quenched induction-coupled plasma torch SO PLASMA CHEMISTRY AND PLASMA PROCESSING LA English DT Article DE atmospheric pressure; FTIR spectroscopy; induction-coupled plasma torch; ozone synthesis; plasma chemistry ID DISCHARGES AB The technical feasibility of using an induction-coupled plasma (ICP) torch to synthesize ozone at atmospheric pressure is explored. Ozone concentrations up to similar to 250 ppm were achieved using a thermal plasma reactor system based on an ICP torch operating at 2.5 MHz and similar to 11 kVA with an argon/oxygen mixture as the plasma-forming gas. The corresponding production rate and yield were similar to 20 g ozone/hr and similar to 2 g ozone/kWh, respectively. A gaseous oxygen quench formed ozone by rapid mixing of molecular oxygen with atomic oxygen produced by the torch. The ozone concentration in the reaction chamber was measured by Fourier Transform infrared (FTIR) spectroscopy over a wide range of experimental conditions and configurations. The geometry of the quench gas flow, the quench flow velocity, and the quench flow rate played important roles in determining the ozone concentration. The ozone concentration was sensitive to the torch RF power, but was insensitive to the torch gas flow rates. These observations are interpreted within the framework of a simple model of ozone synthesis. C1 Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. Drexel Univ, Ctr Plasma Proc Mat, Dept Mat Engn, Philadelphia, PA 19104 USA. Plasma Technol Inc, Santa Fe, NM USA. RP Stratton, BC (reprint author), Princeton Univ, Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 20 TC 7 Z9 7 U1 0 U2 7 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0272-4324 J9 PLASMA CHEM PLASMA P JI Plasma Chem. Plasma Process. PD JUN PY 1999 VL 19 IS 2 BP 191 EP 216 DI 10.1023/A:1021639608291 PG 26 WC Engineering, Chemical; Physics, Applied; Physics, Fluids & Plasmas SC Engineering; Physics GA 192XX UT WOS:000080106000003 ER PT J AU Larson, EM Wong, J Holt, JB Waide, PA Rupp, B AF Larson, EM Wong, J Holt, JB Waide, PA Rupp, B TI The combustion synthesis of the ferroelectric material, BaTiO3, studied by time-resolved X-ray diffraction SO POWDER DIFFRACTION LA English DT Article DE time-resolved diffraction; high temperature synthesis; perovskites; synchrotron radiation; ferroelectric materials AB The combustion synthesis of the common ferroelectric material, BaTiO3, was developed using the stoichiometry: BaO2 + 0.2 Ti + 0.8 TiO2 --> BaTiO3 + 0.3 O-2. An adiabatic temperature, T-ad, of the reaction was calculated from known thermodynamic data to be 1917 degrees C. Real time chemical changes in the formation of BaTiO3 during the reaction have been monitored using time-resolved X-ray diffraction with synchrotron radiation as the X-ray source. A time resolution of 250 ms was achieved. The combustion synthesis of BaTiO3 was followed by observing the intensities of reactant and product Bragg diffraction peaks in order to qualitatively identify the phases present. Because BaTiO3 forms initially as a cubic phase, X-ray diffraction of the product was monitored for a period of 20 min after the reaction to observe the phase transformation to the tetragonal form. This transformation is evident in these post-reaction scans as the cubic 110 and 220 peaks are split to the tetragonal 101/110 and 202/220 ones, respectively. (C) 1999 International Centre for Diffraction Data. [S0885-7156(98)00803-3]. C1 Grand Canyon Univ, Coll Sci & Allied Hlth, Phoenix, AZ 85017 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Larson, EM (reprint author), Grand Canyon Univ, Coll Sci & Allied Hlth, Phoenix, AZ 85017 USA. NR 11 TC 1 Z9 1 U1 1 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0885-7156 J9 POWDER DIFFR JI Powder Diffr. PD JUN PY 1999 VL 14 IS 2 BP 111 EP 113 PG 3 WC Materials Science, Characterization & Testing SC Materials Science GA 204VP UT WOS:000080785600005 ER PT J AU Macol, C Dutta, M Stec, B Tsuruta, H Kantrowitz, ER AF Macol, C Dutta, M Stec, B Tsuruta, H Kantrowitz, ER TI The 80s loop of the catalytic chain of Escherichia coli aspartate transcarbamoylase is critical for catalysis and homotropic cooperativity SO PROTEIN SCIENCE LA English DT Article DE allosteric enzyme; complementation; low-angle X-ray scattering; molecular dynamics ID SITE-SPECIFIC MUTAGENESIS; BISUBSTRATE ANALOG N-(PHOSPHONACETYL)-L-ASPARTATE; PHOSPHATE BINDING-SITE; ACTIVE-SITE; QUATERNARY STRUCTURE; DOMAIN CLOSURE; PYRIDOXAL 5'-PHOSPHATE; ALLOSTERIC TRANSITION; PHENOTYPIC SELECTION; CARBAMOYL PHOSPHATE AB The X-ray structure of the Escherichia coli aspartate transcarbamoylase with the bisubstrate analog phosphonacetyl L-aspartate (PALA) bound shows that PALA interacts with Lys84 from an adjacent catalytic chain. To probe the function of Lys84, site-specific mutagenesis was used to convert Lys84 to alanine, threonine, and asparagine. The K84N and K84T enzymes exhibited 0.08 and 0.29% of the activity of the wild-type enzyme, respectively. However, the K84A enzyme retained 12% of the activity of the wild-type enzyme. For each of these enzymes, the affinity for aspartate was reduced 5- to 10-fold, and the affinity for carbamoyl phosphate was reduced 10- to 30-fold. The enzymes K84N and K84T exhibited no appreciable cooperativity, whereas the K84A enzyme exhibited a Hill coefficient of 1.8. The residual cooperativity and enhanced activity of the K84A enzyme suggest that in this enzyme another mechanism functions to restore catalytic activity. Modeling studies as well as molecular dynamics simulations suggest that in the case of only the K84A enzyme, the lysine residue at position 83 can reorient into the active site and complement for the loss of Lys84. This hypothesis was tested by the creation and analysis of the K83A enzyme and a double mutant enzyme (DM) that has both Lys83 and Lys84 replaced by alanine. The DM enzyme has no cooperativity and exhibited 0.18% of wild-type activity, while the K83A enzyme exhibited 61% of wild-type activity. These data suggest that Lys84 is not only catalytically important, but is also essential for binding both substrates and creation of the high-activity, high-affinity active site. Since low-angle X-ray scattering demonstrated that the mutant enzymes can be converted to the R-structural state, the loss of cooperativity must be related to the inability of these mutant enzymes to form the high-activity, high-affinity active site characteristic of the R-functional state of the enzyme. C1 Boston Coll, Dept Chem, Merkert Chem Ctr, Chestnut Hill, MA 02167 USA. Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Kantrowitz, ER (reprint author), Boston Coll, Dept Chem, Merkert Chem Ctr, Chestnut Hill, MA 02167 USA. FU NIGMS NIH HHS [GM26237] NR 52 TC 6 Z9 6 U1 0 U2 0 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA SN 0961-8368 J9 PROTEIN SCI JI Protein Sci. PD JUN PY 1999 VL 8 IS 6 BP 1305 EP 1313 PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 203KE UT WOS:000080706200016 PM 10386880 ER PT J AU Dubchak, I Muchnik, I Mayor, C Dralyuk, I Kim, SH AF Dubchak, I Muchnik, I Mayor, C Dralyuk, I Kim, SH TI Recognition of a protein fold in the context of the SCOP classification SO PROTEINS-STRUCTURE FUNCTION AND GENETICS LA English DT Article DE protein fold prediction; computer simulated neural networks ID STRUCTURE PREDICTION; SEQUENCES; PATTERNS; FAMILIES AB A computational method has been developed for the assignment of a protein sequence to a folding class in the Structural Classification of Proteins (SCOP). This method uses global descriptors of a primary protein sequence in terms of the physical, chemical, and structural properties of the constituent amino acids. Neural networks are utilized to combine these descriptors in a way to discriminate members of a given fold from members of all other folds. An extensive testing of the method has been performed to evaluate its prediction accuracy. The method is applicable for the fold assignment of any protein sequence with or without significant sequence homology to known proteins. A WWW page for predicting protein folds is available at URL http://cbcg.lbl.gov/. Proteins 1999;35:401407, Published 1999 Wiley-Liss, Inc.dagger. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Rutgers State Univ, Ctr Discrete Math & Theoret Comp Sci DIMACS, Piscataway, NJ USA. RP Dubchak, I (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, MS 84-171, Berkeley, CA 94720 USA. NR 24 TC 119 Z9 128 U1 0 U2 5 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0887-3585 J9 PROTEINS JI Proteins PD JUN 1 PY 1999 VL 35 IS 4 BP 401 EP 407 DI 10.1002/(SICI)1097-0134(19990601)35:4<401::AID-PROT3>3.0.CO;2-K PG 7 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 200KN UT WOS:000080539000003 PM 10382667 ER PT J AU Pellegrini, M Marcotte, EM Yeates, TO AF Pellegrini, M Marcotte, EM Yeates, TO TI A fast algorithm for genome-wide analysis of proteins with repeated sequences SO PROTEINS-STRUCTURE FUNCTION AND GENETICS LA English DT Article DE sub-optimal alignments; Poisson statistics; tandem repeats; Smith-Waterman algorithm; internal duplications ID DUPLICATION AB We present a fast algorithm to search for repeating fragments within protein sequences. The technique is based on an extension of the Smith-Waterman algorithm that allows the calculation of sub-optimal alignments of a sequence against itself. We are able to estimate the statistical significance of all sub-optimal alignment scores. We also rapidly determine the length of the repeating fragment and the number of times it is found in a sequence. The technique is applied to sequences in the Swissprot database, and to 16 complete genomes, We find that eukaryotic proteins contain more internal repeats than those of prokaryotic and archael organisms. The finding that 18% of yeast sequences and 28% of the known human sequences contain detectable repeats emphasizes the importance of internal duplication in protein evolution. Proteins 1999;35:440-446, (C) 1999 Wiley-Liss, Inc. C1 Univ Calif Los Angeles, Inst Mol Biol, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, DOE, Lab Struct Biol & Mol Med, Los Angeles, CA USA. RP Marcotte, EM (reprint author), Univ Calif Los Angeles, Inst Mol Biol, Los Angeles, CA 90095 USA. OI Yeates, Todd/0000-0001-5709-9839 FU NIGMS NIH HHS [GM31299] NR 14 TC 42 Z9 45 U1 0 U2 3 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0887-3585 J9 PROTEINS JI Proteins PD JUN 1 PY 1999 VL 35 IS 4 BP 440 EP 446 DI 10.1002/(SICI)1097-0134(19990601)35:4<440::AID-PROT7>3.0.CO;2-Y PG 7 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 200KN UT WOS:000080539000007 PM 10382671 ER PT J AU Espinosa, G Golzarri, JI Rickards, J Gammage, RB AF Espinosa, G Golzarri, JI Rickards, J Gammage, RB TI Distribution of indoor radon levels in Mexico SO RADIATION MEASUREMENTS LA English DT Article; Proceedings Paper CT 19th International Conference on Nuclear Tracks in Solids (ICNTSs) CY AUG 31-SEP 05, 1998 CL BESANCON, FRANCE DE indoor radon; nuclear track methodology; global information AB Our laboratory has carried out a systematic monitoring and evaluation of indoor radon concentration levels in Mexico for ten years. The results of the distribution of indoor radon levels for practically the entire country are presented, together with information on geological characteristics, population density, socioeconomic levels of the population, and architectural styles of housing. The measurements of the radon levels were made using the passive method of nuclear tracks in solids with the end-cup system. CR-39 was used as the detector material in combination with a one-step chemical etching procedure and an automatic digital- image counting system. Wherever a high level was measured, a confirming measurement was made using a dynamic method. The results are important for future health studies, including the eventual establishment of patterns for indoor radon concentration, as it has been done in the USA and Europe. C1 Univ Nacl Autonoma Mexico, Inst Fis, Mexico City 01000, DF, Mexico. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Espinosa, G (reprint author), Univ Nacl Autonoma Mexico, Inst Fis, Apartado Postal 20364, Mexico City 01000, DF, Mexico. NR 14 TC 17 Z9 17 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1350-4487 J9 RADIAT MEAS JI Radiat. Meas. PD JUN PY 1999 VL 31 IS 1-6 SI SI BP 355 EP 358 DI 10.1016/S1350-4487(99)00171-7 PG 4 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 226AG UT WOS:000081997700067 ER PT J AU Brandt, R Ochs, M Wan, JS Schmidt, T Langrock, EJ Vater, P Adam, J Bamblevskij, VP Bradnova, V Gelovani, LK Kalinnikov, VK Krivopustov, MI Kulakov, BA Sosnin, AN Perelygin, VP Pronskikh, VS Stegailov, VI Tsoupko-Sitnikov, VM Modolo, G Odoj, R Phlippen, PW Adloff, JC Pape, F Debeauvais, M Zamani-Valassiadou, M Hashemi-Nezhad, SR Dwivedi, KK Guo, SL Li, L Wang, YL Wilson, B AF Brandt, R Ochs, M Wan, JS Schmidt, T Langrock, EJ Vater, P Adam, J Bamblevskij, VP Bradnova, V Gelovani, LK Kalinnikov, VK Krivopustov, MI Kulakov, BA Sosnin, AN Perelygin, VP Pronskikh, VS Stegailov, VI Tsoupko-Sitnikov, VM Modolo, G Odoj, R Phlippen, PW Adloff, JC Pape, F Debeauvais, M Zamani-Valassiadou, M Hashemi-Nezhad, SR Dwivedi, KK Guo, SL Li, L Wang, YL Wilson, B TI Transmutation studies using SSNTD and radiochemistry and the associated production of secondary neutrons SO RADIATION MEASUREMENTS LA English DT Article; Proceedings Paper CT 19th International Conference on Nuclear Tracks in Solids (ICNTSs) CY AUG 31-SEP 05, 1998 CL BESANCON, FRANCE DE transmutation; I-129; Np-237; enhanced nuclear cross-section ID ENERGY AB Experiments using 1.5 GeV, 3.7 GeV and 7.4 GeV protons from the Synchrophasotron, LHE, JINR, Dubna, Russia, on extended Pb- and U-targets were carried out using SSNTD and radiochemical sensors for the study of secondary neutron fluences. We also carried out first transmutation studies oil the long-lived radwaste nuclei I-129 and Np-237. In addition, we carried out computer code simulation studies on these systems using LAHET and DCM/CEM codes. We have difficulties to understand rather large transmutation rates observed experimentally when they are compared with computer simulations. There seems to be a rather fundamental problem understanding the large transmutation rates as observed experimentally in Dubna and CERN, as compared to those theoretical computer simulations mentioned above. C1 Univ Marburg, FB 15, D-35032 Marburg, Germany. N, Xian, Peoples R China. NW Inst Nucl Technol, Xian, Peoples R China. Joint Inst Nucl Res, Dubna 141980, Russia. Inst Phys Nucl, CZ-25068 Rez, Czech Republic. FZJ, Forschungszentrum Julich, D-54245 Julich, Germany. Univ Strasbourg 1, Inst Rech Subatom, F-67037 Strasbourg, France. Aristotelian Univ Salonika, Dept Phys, GR-54006 Salonika, Greece. Univ Sydney, Falkiner High Energy Phys Dpt, Sydney, NSW 2006, Australia. NE Hill Univ, Dept Chem, Shillong 793003, Meghalaya, India. China Inst Atom Energy, Beijing 102413, Peoples R China. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Brandt, R (reprint author), Univ Marburg, FB 15, D-35032 Marburg, Germany. RI Adam, Jindrich /G-9788-2014; OI Modolo, Giuseppe/0000-0001-6490-5595 NR 9 TC 10 Z9 13 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1350-4487 J9 RADIAT MEAS JI Radiat. Meas. PD JUN PY 1999 VL 31 IS 1-6 SI SI BP 497 EP 506 DI 10.1016/S1350-4487(99)00100-6 PG 10 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 226AG UT WOS:000081997700096 ER PT J AU Hashemi-Nezhad, SR Brandt, R Ochs, M Wan, JS Schmidt, T Langrock, EJ Vater, P Adam, J Bamblevskij, VP Bradnova, V Gelovani, LK Kalinnikov, VK Krivopustov, MI Kulakov, BA Sosnin, AN Perelygin, VP Pronskikh, VS Stegailov, VI Tsoupko-Sitnikov, VM Modolo, G Odoj, R Phlippen, PW Adloff, JC Debeauvais, M Zamani-Valassiadou, M Dwivedi, KK Wilson, B AF Hashemi-Nezhad, SR Brandt, R Ochs, M Wan, JS Schmidt, T Langrock, EJ Vater, P Adam, J Bamblevskij, VP Bradnova, V Gelovani, LK Kalinnikov, VK Krivopustov, MI Kulakov, BA Sosnin, AN Perelygin, VP Pronskikh, VS Stegailov, VI Tsoupko-Sitnikov, VM Modolo, G Odoj, R Phlippen, PW Adloff, JC Debeauvais, M Zamani-Valassiadou, M Dwivedi, KK Wilson, B TI Studies on neutron production in the interaction of 7.4 GeV protons with extended lead target SO RADIATION MEASUREMENTS LA English DT Article; Proceedings Paper CT 19th International Conference on Nuclear Tracks in Solids (ICNTSs) CY AUG 31-SEP 05, 1998 CL BESANCON, FRANCE DE neutron distribution; subcritical systems; LR 115 2B detector ID ENERGY AB A cylindrical lead target of diameter 8 cm and length 20 cm was irradiated with 7.4 GeV protons along the axis of the cylinder. The lead target was surrounded with a paraffin layer of thickness 6 cm to moderate the neutrons produced in p + Pb reactions. The spatial distribution of the slow and fast neutrons on different surfaces of the moderator were determined using LR 115 2B detectors (through (10)(n,alpha)Li-7 reactions) and CR39 detectors (through proton recoils) respectively. Such results can be valuable in the studies and design of Accelerator Driven Subcritical Nuclear Reactors and Nuclear Waste Incinerators. C1 Univ Sydney, Sch Phys, Dept High Energy Phys, Sydney, NSW 2006, Australia. Univ Marburg, D-35032 Marburg, Germany. Joint Inst Nucl Res, Dubna 141980, Russia. FZJ, Forschungszentrum Julich, D-54245 Julich, Germany. Univ Strasbourg 1, Inst Rech Subatom, F-67037 Strasbourg, France. Aristotelian Univ Salonika, Dept Phys, GR-54006 Salonika, Greece. NE Hill Univ, Dept Chem, Shillong 793003, Meghalaya, India. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Hashemi-Nezhad, SR (reprint author), Univ Sydney, Sch Phys, Dept High Energy Phys, Sydney, NSW 2006, Australia. OI Modolo, Giuseppe/0000-0001-6490-5595 NR 8 TC 10 Z9 11 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1350-4487 J9 RADIAT MEAS JI Radiat. Meas. PD JUN PY 1999 VL 31 IS 1-6 SI SI BP 537 EP 544 DI 10.1016/S1350-4487(99)00183-3 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 226AG UT WOS:000081997700102 ER PT J AU Wilson, JW Cucinotta, FA Shinn, JL Simonsen, LC Dubey, RR Jordan, WR Jones, TD Chang, CK Kim, MY AF Wilson, JW Cucinotta, FA Shinn, JL Simonsen, LC Dubey, RR Jordan, WR Jones, TD Chang, CK Kim, MY TI Shielding from solar particle event exposures in deep space SO RADIATION MEASUREMENTS LA English DT Article; Proceedings Paper CT Workshop on Impact of Solar Energetic Particle Events for the Design of Human Space Missions CY SEP 09-11, 1997 CL CTR ADV SPACE STUDIES, HOUSTON, TEXAS HO CTR ADV SPACE STUDIES DE solar particle events; shielding; biological response; mortality; tissue environments ID CELL-KINETICS; CYTOPENIA; PHOTONS; MODELS; DEATH AB The physical composition and intensities of solar particle event exposures of sensitive astronaut tissues are examined under conditions approximating an astronaut in deep space. Response functions for conversion of particle fluence into dose and dose equivalent averaged over organ tissues are used to establish significant fluence levels and the expected dose and dose rates of the most important events from past observations. The BRYNTRN transport code is used to evaluate the local environment experienced by sensitive tissues and used to evaluate bioresponse models developed for use in tactical nuclear warfare. The present results will help to clarify the biophysical aspects of such exposure in the assessment of RBE and dose rate effects and their impact on design of protection systems for the astronauts. The use of polymers as shielding material in place of an equal mass of aluminum would provide a large safety factor without increasing the vehicle mass. This safety factor is sufficient to provide adequate protection if a factor of two larger event than has ever been observed in fact occurs during the mission. Published by Elsevier Science Ltd. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Old Dominion Univ, Norfolk, VA 23508 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Christopher Newport Univ, Newport News, VA 23601 USA. Natl Res Council, Washington, DC 20418 USA. RP Wilson, JW (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 25 TC 63 Z9 64 U1 1 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1350-4487 J9 RADIAT MEAS JI Radiat. Meas. PD JUN PY 1999 VL 30 IS 3 BP 361 EP 382 DI 10.1016/S1350-4487(99)00063-3 PG 22 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 255LU UT WOS:000083671000016 PM 11543148 ER PT J AU Cooke, DW Muenchusen, RE Bennett, BL Orler, EB Wrobleski, DA Smith, ME Jahan, MS Thomas, DE AF Cooke, DW Muenchusen, RE Bennett, BL Orler, EB Wrobleski, DA Smith, ME Jahan, MS Thomas, DE TI Luminescence, optical absorption and electron spin resonance of an X-irradiated poly(ester urethane) SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article ID POLYURETHANE BLOCK COPOLYMERS; MULTIPLE ENDOTHERMIC BEHAVIOR; ORGANIC POLYMERS; CONDUCTIVITY; DEGRADATION; DSC AB X-ray-induced damage in Estane (R) 5703, a segmented poly(ester urethane) copolymer, has been investigated by thermally stimulated luminescence, radioluminescence, optical absorption and electron spin resonance techniques over a wide temperature range. Some glow curve features correlate with molecular motion of the polymer, as determined by viscoelastic measurements, indicating charge detrapping via thermal destruction of cavity traps. Spectral emission consists of four Lorentzian bands with maxima at 2.38, 2.55, 2.74 and 2.93 eV, which are attributed to triplet-to-singlet (pi, pi*) electronic transitions of the phenyl group in the polymer hard segment. Absorption peaks at 3.97, 4.29 and 4.46 eV are also assigned to (pi, pi*) transitions of the phenyl group. Several radicals with overlapping resonances are induced at low temperature, which, with increasing temperature, evolve into the relatively stable peroxy radical at room temperature. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. Univ Memphis, Dept Phys, Memphis, TN 38152 USA. RP Cooke, DW (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, MST-8,MS E546, Los Alamos, NM 87545 USA. NR 41 TC 10 Z9 10 U1 1 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-806X J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD JUN PY 1999 VL 55 IS 1 BP 1 EP 13 DI 10.1016/S0969-806X(98)00340-5 PG 13 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA 187WX UT WOS:000079812200001 ER PT J AU Limoli, CL Corcoran, JJ Milligan, JR Ward, JF Morgan, WF AF Limoli, CL Corcoran, JJ Milligan, JR Ward, JF Morgan, WF TI Critical target and dose and dose-rate responses for the induction of chromosomal instability by ionizing radiation SO RADIATION RESEARCH LA English DT Article ID CHINESE-HAMSTER CELLS; INDIRECT MECHANISMS CONTRIBUTE; DELAYED REPRODUCTIVE DEATH; ALPHA-PARTICLE IRRADIATION; DNA-INCORPORATED I-125; DOUBLE-STRAND BREAKS; GENOMIC INSTABILITY; HUMAN FIBROBLASTS; MAMMALIAN-CELLS; CELLULAR RADIOSENSITIZATION AB To investigate the critical target, dose response and dose-rate response for the induction of chromosomal instability by ionizing radiation, bromodeoxyuridine (BrdU)-substituted and unsubstituted GM10115 cells were exposed to a range of doses (0.1-10 Gy) and different dose rates (0.092-17.45 Gy min(-1)), The status of chromosomal stability was determined by fluorescence in situ hybridization approximately 20 generations after irradiation in clonal populations derived from single progenitor cells surviving acute exposure. Overall, nearly 700 individual clones representing over 140,000 metaphases were analyzed, In cells unsubstituted with BrdU, a dose response was found, where the probability of observing delayed chromosomal instability in any given clone was 3% per gray of X rays. For cells substituted with 25-66% BrdU, however, a dose response was observed only at low doses (<1.0 Gy); at higher doses (>1.0 Gy), the incidence of chromosomal instability leveled off. There was an increase in the frequency and complexity of chromosomal instability per unit dose compared to cells unsubstituted with BrdU, The frequency of chromosomal instability appeared to saturate around similar to 30%, an effect which occurred at much lower doses in the presence of BrdU, Changing the gamma-ray dose rate by a factor of 190 (0.092 to 17.45 Gy min(-1)) produced no significant differences in the frequency of chromosomaI instability. The enhancement of chromosomal instability promoted by the presence of the BrdU argues that DNA comprises at least one of the critical targets important for the induction of this end point of genomic instability. (C) 1999 by Radiation Research Society. C1 Univ Calif San Francisco, Dept Radiol, San Francisco, CA 94143 USA. Univ Calif San Francisco, Dept Radiat Oncol, San Francisco, CA 94143 USA. Univ Calif San Diego, Dept Radiol, La Jolla, CA 92093 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP Limoli, CL (reprint author), Univ Calif San Francisco, Dept Radiol, San Francisco, CA 94143 USA. FU NCI NIH HHS [CA46295]; NIGMS NIH HHS [GM 54189] NR 40 TC 63 Z9 69 U1 0 U2 1 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 USA SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD JUN PY 1999 VL 151 IS 6 BP 677 EP 685 DI 10.2307/3580206 PG 9 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 201NU UT WOS:000080602300006 PM 10360787 ER PT J AU Coutts, TJ AF Coutts, TJ TI A review of progress in thermophotovoltaic generation of electricity SO RENEWABLE & SUSTAINABLE ENERGY REVIEWS LA English DT Review ID PERFORMANCE; FILTERS; CELL C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Coutts, TJ (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. NR 110 TC 146 Z9 163 U1 3 U2 68 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-0321 J9 RENEW SUST ENERG REV JI Renew. Sust. Energ. Rev. PD JUN-SEP PY 1999 VL 3 IS 2-3 BP 77 EP 184 DI 10.1016/S1364-0321(98)00021-5 PG 108 WC GREEN & SUSTAINABLE SCIENCE & TECHNOLOGY; Energy & Fuels SC Science & Technology - Other Topics; Energy & Fuels GA 298HF UT WOS:000086132700001 ER PT J AU Jarvis, GK Song, Y Ng, CY AF Jarvis, GK Song, Y Ng, CY TI High resolution pulsed field ionization photoelectron spectroscopy using multibunch synchrotron radiation: Time-of-flight selection scheme SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID RESOLVED PHOTOELECTRON; VACUUM-ULTRAVIOLET; THRESHOLD; ENERGY; PHOTOIONIZATION; STATES; O-2 AB We have developed an efficient electron time-of-flight (TOF) selection scheme for high resolution pulsed field ionization (PFI) photoelectron (PFI-PE) measurements using monochromatized multibunch undulator synchrotron radiation at the Advanced Light Source. By employing a simple electron TOF spectrometer, we show that PFI-PEs produced by the PFI in the dark gap of a synchrotron ring period can be cleanly separated from prompt background photoelectrons. A near complete suppression of prompt electrons was achieved in PFI-PE measurements by gating the PFI-PE TOF peak, as indicated by monitoring background electron counts at the Ar(11s') autoionizing Rydberg peak, which is adjacent to the Ar+(P-2(3/2)) PFI-PE band. The rotational-resolved PFI-PE band for H-2(+) (X (2)Sigma(g)(+), v(+) = 0) measured using this electron TOF selection scheme is nearly free from residues of nearby autoionizing features, which were observed in the previous measurement by employing an electron spectrometer equipped with a hemispherical energy analyzer. This comparison indicates that the TOF PFI-PE scheme is significantly more effective in suppressing the hot-electron background. In addition to attaining a high PFI- PE transmission, a major advantage of the electron TOF scheme is that it allows the use of a smaller pulsed electric field and thus results in a higher instrumental PFI-PE resolution. We have demonstrated instrumental resolutions of 1.0 cm(-1) full width at half maximum (FWHM) and 1.9 cm(-1) FWHM in the PFI-PE bands for Xe+(P-2(3/2)) and Ar+(P-2(3/2)) at 12.123 and 15.760 eV, respectively. These resolutions are more than a factor 2 better than those achieved in previous synchrotron based PFI- PE studies. (C) 1999 American Institute of Physics. [S0034-6748(99)02006-7]. C1 Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Ng, CY (reprint author), Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA. NR 30 TC 51 Z9 54 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUN PY 1999 VL 70 IS 6 BP 2615 EP 2621 DI 10.1063/1.1149818 PG 7 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 201UH UT WOS:000080613500005 ER PT J AU Swenson, CA AF Swenson, CA TI Specific heat (Cp) of Apiezon N grease, (1 to 108 K) and calorimetry: Cp of copper below 30 K SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID CAPACITY DATA; EXPANSIVITY; CRYSTALS AB Heat capacity (C-p) data for Apiezon N grease from 1 to 108 K are compared with previous results for this grease and for Apiezon T, with good agreement. Addenda results for a calorimeter in which Apiezon N grease is used for thermal contact between the tray and a sample suggest that a thin film of this grease has an appreciably larger C-p, below 4 K, than bulk grease. For high accuracy experiments using Apiezon N grease, care should be taken in the calculation of addenda C-p's from bare tray data and the C-p for bulk grease. During these measurements, C-p data for a high purity electron beam melted copper sample were found to be in excellent agreement from 1 to 30 K (+/-60.2%) with previous measurements [Holste, Cetas, and Swenson, Rev. Sci. Instrum. 43, 670 (1972)] on a different sample using a quite different calorimeter. (C) 1999 American Institute of Physics. [S0034-6748(99)02106-1]. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Swenson, CA (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 17 TC 15 Z9 15 U1 1 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUN PY 1999 VL 70 IS 6 BP 2728 EP 2731 DI 10.1063/1.1149836 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 201UH UT WOS:000080613500023 ER PT J AU Jannik, GT AF Jannik, GT TI Critical radionuclide/critical pathway analysis for the US Department of Energy's Savannah River Site SO RISK ANALYSIS LA English DT Article DE pathway analysis; radiological risk assessment; dose assessment AB Many different radionuclides have been released to the environment from the Savannah River Site (SRS) during the facility's operational history. However, as shown by this analysis, only a small number of the released radionuclides have been significant contributors to potential doses and risks to off-site people. This article documents the radiological critical contaminant/critical pathway analysis performed for SRS. If site missions and operations remain constant over the next 30 years, only tritium oxide releases are projected to exceed a maximally exposed individual (MEI) risk of 1.0E-06 for either the airborne or liquid pathways. The critical exposure pathways associated with site airborne releases are inhalation and vegetation consumption, whereas the critical exposure pathways associated with liquid releases are drinking water and fish consumption. For the SRS-specific, nontypical exposure pathways (i.e., recreational fishing and deer and hog hunting), cesium-137 is the critical radionuclide. C1 Westinghouse Savannah River Co, Savannah River Technol Ctr, Aiken, SC 29808 USA. RP Jannik, GT (reprint author), Westinghouse Savannah River Co, Savannah River Technol Ctr, Bldg 773-42A,Room 226,Savannah River Site, Aiken, SC 29808 USA. NR 26 TC 3 Z9 3 U1 1 U2 2 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0272-4332 J9 RISK ANAL JI Risk Anal. PD JUN PY 1999 VL 19 IS 3 BP 417 EP 426 DI 10.1023/A:1007096511628 PG 10 WC Public, Environmental & Occupational Health; Mathematics, Interdisciplinary Applications; Social Sciences, Mathematical Methods SC Public, Environmental & Occupational Health; Mathematics; Mathematical Methods In Social Sciences GA 231JA UT WOS:000082303800009 PM 10765414 ER PT J AU Burger, J Stephens, WL Boring, CS Kuklinski, M Gibbons, JW Gochfeld, M AF Burger, J Stephens, WL Boring, CS Kuklinski, M Gibbons, JW Gochfeld, M TI Factors in exposure assessment: Ethnic and socioeconomic differences in fishing and consumption of fish caught along the Savannah River SO RISK ANALYSIS LA English DT Article DE ethnicity; fish consumption; advisories; Savannah River; methylmercury; risk perception ID FOOD-CONSUMPTION; RISK; METHYLMERCURY; PERCEPTION; COMMUNITY; POLLUTION; FISHERMEN; INGESTION; HAZARDS; MERCURY AB South Carolina has issued fish consumption advisories for the Savannah River based on mercury and radionuclide levels. We examine differences in fishing rates and fish consumption of 258 people interviewed while fishing along the Savannah River, as a function of age, education, ethnicity, employment history, and income, and test the assumption that the average consumption of fish is less than the recreational value of 19 kg/year assumed by risk assessors. Ethnicity and education contributed significantly to explaining variations in number of fish meals per month, serving size, and total quantity of fish consumed per year. Blacks fished more often, ate more fish meals of slightly larger serving sizes, and consumed more fish per year than did Whites. Although education and income were correlated, education contributed most significantly to behavior; people who did not graduate from high school ate fish more often, ate more fish per year, and ate more whole fish than people who graduated from high school. Computing consumption of fish for each person individually indicates that (1) people who eat fish more often also eat larger portions, (2) a substantial number of people consume more than the amount of fish used to compute risk to recreational fishermen, (3) some people consume more than the subsistence level default assumption (50 kg/year) and (4) Blacks consume more fish per year than Whites, putting them at greater risk from contaminants in fish. Overall, ethnicity, age, and education contributed to variations in fishing behavior and consumption. C1 Rutgers State Univ, Nelson Biol Lab, Piscataway, NJ 08854 USA. Enviornm & Occupat Hlth Sci Inst, Consortium Risk Evaluat Stakeholder Participat, Piscataway, NJ 08854 USA. Savannah River Ecol Lab, Aiken, SC 29802 USA. Univ Med & Dent New Jersey, Robert Wood Johnson Med Sch, Piscataway, NJ 08854 USA. RP Burger, J (reprint author), Rutgers State Univ, Nelson Biol Lab, 604 Allison Rd, Piscataway, NJ 08854 USA. NR 40 TC 61 Z9 63 U1 2 U2 13 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0272-4332 J9 RISK ANAL JI Risk Anal. PD JUN PY 1999 VL 19 IS 3 BP 427 EP 438 DI 10.1023/A:1007048628467 PG 12 WC Public, Environmental & Occupational Health; Mathematics, Interdisciplinary Applications; Social Sciences, Mathematical Methods SC Public, Environmental & Occupational Health; Mathematics; Mathematical Methods In Social Sciences GA 231JA UT WOS:000082303800010 PM 10765415 ER PT J AU Ottesen, D Allendorf, S Ludowise, P Hardesty, D Goldstein, D Miller, T Smith, C Bonin, M AF Ottesen, D Allendorf, S Ludowise, P Hardesty, D Goldstein, D Miller, T Smith, C Bonin, M TI A laser-based sensor for measurement of off-gas composition and temperature in basic oxygen steelmaking SO SCANDINAVIAN JOURNAL OF METALLURGY LA English DT Article DE optical sensor; process-control; off-gas; bath temperature; bath carbon; BOF steelmaking AB We are developing an optical sensor for process control in basic oxygen steelmaking. The sensor measures gas temperature and relative CO/CO2 concentration ratios through the furnace off-gas during oxygen blowing. In the current configuration, the laser beam is transmitted through the process off-gas directly above the furnace lip and below the exhaust hood, and is being tested at Bethlehem Steel's Sparrows Point Division, Baltimore, MD. Rapid analysis of the detected laser radiation provides the input for real-time control of steelmaking processes. Dynamic gas composition and temperature information provided by this technique are being evaluated for optimizing variables such as lance height, oxygen flow, post-combustion control, and prediction of final-turndown bath temperature and carbon content. The noninvasive nature of the optical sensor renders it robust, relatively maintenance-free, and useful for characterizing off-gas streams in general. Additional applications of the method are process control for electric furnace and bottom-blown oxygen steel-making processes. C1 Sandia Natl Labs, Livermore, CA 94551 USA. Bethlehem Steel Corp, Homer Res Labs, Bethlehem, PA 18016 USA. Bethlehem Steel Corp, Sparrows Point Div, Baltimore, MD 21219 USA. Insitec Measurement Syst, San Ramon, CA 94583 USA. RP Ottesen, D (reprint author), Sandia Natl Labs, POB 969, Livermore, CA 94551 USA. NR 10 TC 3 Z9 3 U1 1 U2 1 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0371-0459 J9 SCAND J METALL JI Scand. J. Metall. PD JUN PY 1999 VL 28 IS 3 BP 131 EP 137 PG 7 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA 258FC UT WOS:000083826600005 ER PT J AU Fang, M Vetelino, K Rothery, M Hines, J Frye, GC AF Fang, M Vetelino, K Rothery, M Hines, J Frye, GC TI Detection of organic chemicals by SAW sensor array SO SENSORS AND ACTUATORS B-CHEMICAL LA English DT Article DE organic chemicals; SAW sensor array; chlorinated hydrocarbons AB A portable SAW sensor array instrument with integrated chemometric software has been developed to identify a variety of chemical classes like paraffinics, aromatics, chlorinated hydrocarbons, ketones and alcohols. The system was trained with known chemicals and a chemometric model was developed for two applications: bulk VOC identification and environmental monitoring of trace level VOCs. The instrument was then successfully tested in the lab and in the field for these two applications. The ability to identify and quantify these VOCs over a dynamic range from low ppm trace levels to high concentrations (close to the chemical's vapor pressure) was demonstrated. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Sawtek, Orlando, FL 32860 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Fang, M (reprint author), Sawtek, POB 609501, Orlando, FL 32860 USA. NR 3 TC 33 Z9 33 U1 0 U2 5 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-4005 J9 SENSOR ACTUAT B-CHEM JI Sens. Actuator B-Chem. PD JUN 1 PY 1999 VL 56 IS 1-2 BP 155 EP 157 DI 10.1016/S0925-4005(99)00176-8 PG 3 WC Chemistry, Analytical; Electrochemistry; Instruments & Instrumentation SC Chemistry; Electrochemistry; Instruments & Instrumentation GA 212EJ UT WOS:000081203700023 ER PT J AU Johnson, JN Cheret, R AF Johnson, JN Cheret, R TI Shock waves in solids: an evolutionary perspective SO SHOCK WAVES LA English DT Article DE history; solids; polymorphic phase transition; elastic-plastic transition; equation of state AB A historical summary of the early classic papers in shock compression science is presented with the purpose of establishing the foundations for more recent studies of shock waves in solids. The major (largely theoretical) works of the period from 1808 to 1949 have been previously brought together into a single collection [Johnson and Cheret, Springer-Verlag, New York, 1998]. Important papers on shock waves in condensed matter from 1948 to the present were not included in the collection, largely because of their relatively easy accessibility. This paper provides a supplement to the original collection allowing research workers and historians to trace the major developments leading to the establishment of the unique field of shock compression in solids. C1 Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. CEA, Paris, France. RP Johnson, JN (reprint author), Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 34 TC 5 Z9 5 U1 0 U2 1 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0938-1287 EI 1432-2153 J9 SHOCK WAVES JI Shock Waves PD JUN PY 1999 VL 9 IS 3 BP 193 EP 200 DI 10.1007/s001930050154 PG 8 WC Mechanics SC Mechanics GA 212GN UT WOS:000081209100006 ER PT J AU Hikosaka, H Kusaba, K Syono, Y Bennett, LS Tanaka, K Katayama, M AF Hikosaka, H Kusaba, K Syono, Y Bennett, LS Tanaka, K Katayama, M TI Numerical analysis in the shock synthesis of EuBa2Cu3Oy SO SHOCK WAVES LA English DT Article DE shock synthesis; shock recovery experiments; high T-c oxides; EuBa2Cu3Oy; numerical calculation; Mach reflection ID SILICIDES AB Numerical calculations using two material models, a P-alpha model and the VIR model with and without reaction, were applied for the shock synthesis of EuBa2Cu3Oy. The shock wave was reflected from the back rim of the sample due to a faster shock wave velocity in the container than in the sample, achieving very high pressure. The temperature calculated in the outer area of the 3-mm-thick sample was higher than that of the center region because of single compression due to Mach reflection. The calculated temperature distribution in the 1-mm-thick samples was less remarkable than in the 3-mm-thick samples. The temperature calculated using the VIR model with reaction was higher than that of the P-alpha model without reaction due to the occurrence of exothermic reaction. The result of a shock recovery experiment from a 3-mm-thick sample indicated that the yield of EuBa2Cu3Oy phase in the outer area of the sample was larger than that of the central area. The large yield in the outer area was consistent with the result of numerical calculation. A more-homogeneous temperature distribution achieved in a 1-mm-thick sample than in a 3 mm thick sample indicated that the aspect ratio of the sample room is important for shock synthesis experiments. C1 Tohoku Univ, Inst Mat Res, Sendai, Miyagi 9808577, Japan. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Natl Inst Mat & Chem Res, Tsukuba, Ibaraki 3058565, Japan. CRC Res Inst Inc, Koto Ku, Tokyo 1368581, Japan. RP Syono, Y (reprint author), Tohoku Univ, Inst Mat Res, Katahira 2-1-1, Sendai, Miyagi 9808577, Japan. NR 22 TC 0 Z9 0 U1 1 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0938-1287 J9 SHOCK WAVES JI Shock Waves PD JUN PY 1999 VL 9 IS 3 BP 201 EP 207 DI 10.1007/s001930050155 PG 7 WC Mechanics SC Mechanics GA 212GN UT WOS:000081209100007 ER PT J AU Rosen, K Van Buskirk, R Garbesi, K AF Rosen, K Van Buskirk, R Garbesi, K TI Wind energy potential of coastal Eritrea: An analysis of sparse wind data SO SOLAR ENERGY LA English DT Article ID RESOURCES AB This paper describes an analysis of historical surface wind data for the small country of Eritrea, in northeastern Africa. Winds in this region are directed by summer and winter monsoons in addition to diurnal land-sea effects. An analysis of national Eritrean and historical Italian wind records indicated marginal wind resources in the central highlands near the Eritrean capital of Asmera. An analysis of wind speed records recorded at two sites in the southern port city of Aseb indicate mean annual 10-m wind speeds of 9.5 m s(-1) at the windier site. Surface wind speed records for the Red Sea suggest that similar potential may be found along the lower 200 km of the Eritrean coastline. Based on these findings, wind-generated electricity in this region should be substantially cheaper than the current supply generated from imported diesel. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. San Jose State Univ, Dept Environm Studies, San Jose, CA 95192 USA. RP Rosen, K (reprint author), Lawrence Berkeley Natl Lab, MS 90-2000, Berkeley, CA 94720 USA. NR 12 TC 20 Z9 20 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0038-092X J9 SOL ENERGY JI Sol. Energy PD JUN PY 1999 VL 66 IS 3 BP 201 EP 213 DI 10.1016/S0038-092X(99)00026-2 PG 13 WC Energy & Fuels SC Energy & Fuels GA 212RU UT WOS:000081230700003 ER PT J AU Peles, JD Weathersbee, FW Johns, PE Griess, J Baker, DL Smith, MH AF Peles, JD Weathersbee, FW Johns, PE Griess, J Baker, DL Smith, MH TI Genetic variation in a recently isolated population of mule deer (Odocoileus hemionus) SO SOUTHWESTERN NATURALIST LA English DT Article ID WHITE-TAILED DEER; VARIABILITY C1 Savannah River Ecol Lab, Aiken, SC 29802 USA. RP Peles, JD (reprint author), Savannah River Ecol Lab, Drawer E, Aiken, SC 29802 USA. NR 20 TC 0 Z9 0 U1 2 U2 3 PU SOUTHWESTERN ASSN NATURALISTS PI SAN MARCOS PA SOUTHWEST TEXAS STATE UNIV, DEPT BIOLOGY, 601 UNIVERSITY DR, SAN MARCOS, TX 78666 USA SN 0038-4909 J9 SOUTHWEST NAT JI Southw. Natural. PD JUN PY 1999 VL 44 IS 2 BP 236 EP 240 PG 5 WC Biodiversity Conservation; Ecology SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 208GP UT WOS:000080982900019 ER PT J AU Zhang, DX Winter, CL AF Zhang, Dongxiao Winter, C. L. TI Moment-Equation Approach to Single Phase Fluid Flow in Heterogeneous Reservoirs SO SPE JOURNAL LA English DT Article AB In this paper, we study single phase, steady-state flow in bounded, heterogeneous reservoirs. We derive general equations governing the statistical moments of flow quantities by perturbation expansions. These moments may be used to construct confidence intervals for the flow quantities. Due to their mathematical complexity, we solve the moment differential equations (MDEs) by the numerical technique of finite differences. The numerical MDE approach renders the flexibility in handling complex flow configurations, different boundary conditions, various covariance functions of the independent variables, and moderately irregular geometry, all of which are important factors to consider for real-world applications. The other method with these flexibilities is Monte Carlo simulation (MCS) which has been widely used in the industry. These two approaches are complementary, and each has its own advantages and disadvantages. The numerical MDE approach is compared with published results of MCS and analytical MDE approaches and is demonstrated with two examples involving injection/production wells. C1 [Zhang, Dongxiao; Winter, C. L.] Los Alamos Natl Lab, Los Alamos, NM 87544 USA. RP Zhang, DX (reprint author), Los Alamos Natl Lab, Los Alamos, NM 87544 USA. EM dongzhang@lanl.gov; winter@lanl.gov RI Zhang, Dongxiao/D-5289-2009 OI Zhang, Dongxiao/0000-0001-6930-5994 FU LDRD Project from Los Alamos National Laboratory (LANL) [97528] FX This work was funded by LDRD Project No. 97528 from Los Alamos National Laboratory (LANL), which is operated by the University of California for the U.S. Department of Energy. The authors wish to thank Jack Jones at BP Amoco and Rajesh Pawar at LANL for their helpful suggestions on this work. NR 33 TC 42 Z9 42 U1 0 U2 0 PU SOC PETROLEUM ENG PI RICHARDSON PA 222 PALISADES CREEK DR,, RICHARDSON, TX 75080 USA SN 1086-055X EI 1930-0220 J9 SPE J JI SPE J. PD JUN PY 1999 VL 4 IS 2 BP 118 EP 127 PG 10 WC Engineering, Petroleum SC Engineering GA V33KD UT WOS:000209016800006 ER PT J AU Chadwick, MB Jones, DTL Barschall, HH Caswell, RS DeLuca, PM Meulders, JP Wambersie, A Schuhmacher, H Young, PG Hale, GM Siebers, JV AF Chadwick, MB Jones, DTL Barschall, HH Caswell, RS DeLuca, PM Meulders, JP Wambersie, A Schuhmacher, H Young, PG Hale, GM Siebers, JV TI Nuclear data for radiotherapy: Presentation of a new ICRU report and IAEA initiatives SO STRAHLENTHERAPIE UND ONKOLOGIE LA English DT Article DE neutron therapy; proton therapy; radiation protection; nuclear data ID NEUTRON-INDUCED REACTIONS; PRODUCTION CROSS-SECTIONS; DIFFERENTIAL INCLUSIVE HYDROGEN; KERMA FACTORS; PARTICLE PRODUCTION; HELIUM SPECTRA; CARBON; ENERGIES; PROTON; 30-MEV AB An ICRU report entitled "Nuclear Data for Neutron and Proton Radiotherapy and for Radiation Protection" is in preparation. The present paper presents an overview of this report, along with examples of some of the results obtained for evaluated nuclear cross sections and kerma coefficients. These cross sections are evaluated using a combination of measured data and the GNASH nuclear model code for elements of importance for biological, dosimetric, beam modification and shielding purposes. In the case of hydrogen both R-matrix and phase-shift scattering theories are used. In the report neutron cross sections and kerma coefficients will be presented up to 150 MeV and proton cross sections up to 250 MeV. An IAEA Consultants' Meeting was also convened to examine the "Status of Nuclear Data needed for Radiation Therapy and Existing Data Development Activities in Member States". Recommendations were made regarding future endeavours. C1 Univ Calif Los Alamos Natl Lab, Grp Nucl Theory & Applicat T2, Los Alamos, NM 87545 USA. Natl Accelerator Ctr, ZA-7131 Faure, South Africa. Univ Wisconsin, Madison, WI USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Catholic Univ Louvain, B-3000 Louvain, Belgium. Phys Tech Bundesanstalt, D-3300 Braunschweig, Germany. Loma Linda Univ, Med Ctr, Loma Linda, CA USA. RP Chadwick, MB (reprint author), Univ Calif Los Alamos Natl Lab, Grp Nucl Theory & Applicat T2, Los Alamos, NM 87545 USA. NR 32 TC 0 Z9 0 U1 0 U2 1 PU URBAN & VOGEL PI MUNICH PA LINDWURMSTRASSE 95, D-80337 MUNICH, GERMANY SN 0179-7158 J9 STRAHLENTHER ONKOL JI Strahlenther. Onkol. PD JUN PY 1999 VL 175 SU 2 BP 26 EP 29 PG 4 WC Oncology; Radiology, Nuclear Medicine & Medical Imaging SC Oncology; Radiology, Nuclear Medicine & Medical Imaging GA 208MR UT WOS:000080995600011 PM 10394391 ER PT J AU Bryan, JC Delmau, LH Hay, BP Nicholas, JB Rogers, LM Rogers, RD Moyer, BA AF Bryan, JC Delmau, LH Hay, BP Nicholas, JB Rogers, LM Rogers, RD Moyer, BA TI Cesium recognition by supramolecular assemblies of 2-benzylphenol and 2-benzylphenolate SO STRUCTURAL CHEMISTRY LA English DT Article DE cesium; 2-benzylphenol; Pi-cation interaction; extraction; molecular mechanics ID RAY CRYSTAL-STRUCTURES; CATION-PI INTERACTIONS; CHELATE RING SIZE; METAL-IONS; SOLVENT-EXTRACTION; SELECTIVE LIGANDS; RATIONAL DESIGN; DONOR GROUPS; FORCE-FIELD; ALKALI AB Extraction experiments show that 2-benzylphenol is an efficient and selective extractant for cesium. The structures of cesium and potassium 2-benzylphenolate were determined. Both structures also contain 2-benzylphenol, which ligates the cation, through its phenolic oxygen atom and the benzyl ring. The phenolate oxygen atom does not directly contact the cation in either structure, but is a hydrogen-bond acceptor to the 2-benzylphenol ligands, forming a supramolecular assembly. For comparison to the bound ligands, the structure of 2-benzylphenol was also determined. Molecular mechanics and ab initio molecular orbital theory are used to rationalize several aspects of Cs/Na selectivity. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Univ Alabama, Dept Chem, Tuscaloosa, AL 35487 USA. RP Bryan, JC (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RI Solominow, Sonia/A-4021-2008; Rogers, Robin/C-8265-2013; Moyer, Bruce/L-2744-2016 OI Rogers, Robin/0000-0001-9843-7494; Moyer, Bruce/0000-0001-7484-6277 NR 64 TC 16 Z9 17 U1 0 U2 6 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1040-0400 J9 STRUCT CHEM JI Struct. Chem. PD JUN PY 1999 VL 10 IS 3 BP 187 EP 203 DI 10.1023/A:1021884429538 PG 17 WC Chemistry, Multidisciplinary; Chemistry, Physical; Crystallography SC Chemistry; Crystallography GA 217XH UT WOS:000081523900004 ER PT J AU Merchant, NN Luo, JS Fischer, AK Maroni, VA Podtburg, ER Carter, WL Li, Q Otto, A Rupich, MW Riley, GN AF Merchant, NN Luo, JS Fischer, AK Maroni, VA Podtburg, ER Carter, WL Li, Q Otto, A Rupich, MW Riley, GN TI Phase formation and microstructure development in silver-clad Bi-2223 multifilament composite conductors SO SUPERCONDUCTOR SCIENCE & TECHNOLOGY LA English DT Article ID CRITICAL-CURRENT DENSITY; METALLIC PRECURSOR PROCESS; TAPES; EVOLUTION; WIRE; SUPERCONDUCTORS; FILAMENTS; STABILITY; MECHANISM; KINETICS AB Phase evolution and microstructure development in silver-clad Bi-2223 composite conductors have been investigated as a function of filament count (mono, 19, 85 and 361), precursor powder type (metallic powder or oxide powder), oxygen partial pressure (<10(-3) to 0.13 atm), temperature (790-855 degrees C) and time (0-6000 min). Favourable conditions for rapid Bi-2223 phase formation and stability were achieved with an oxygen partial pressure around 0.08 atm, regardless of precursor type or filament count. In general, the rate of the Bi-2223 formation reaction increased and the width of the temperature window for rapid kinetics became broader as the filament count increased. The most rapid kinetics and the broadest heat treatment window were observed for the 361-filament metallic powder composite. These trends in Bi-2223 formation rate and stability are believed to be associated with the increased proximity of powder to silver as the filament count increases and the filament transverse dimensions become smaller For each conductor type (in terms of precursor form and filament type) there was an optimum processing temperature in ca 0.08 atm O-2 that produced a well-developed Bi-2223 grain colony microstructure with the least amount of second-phase. This optimum temperature was near the peak of the reaction rate Versus temperature profile. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Amer Superconductor, Westborough, MA 01581 USA. RP Maroni, VA (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 31 TC 15 Z9 15 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-2048 J9 SUPERCOND SCI TECH JI Supercond. Sci. Technol. PD JUN PY 1999 VL 12 IS 6 BP 327 EP 336 DI 10.1088/0953-2048/12/6/301 PG 10 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 210JV UT WOS:000081102200003 ER PT J AU Kirova, N Brazovskii, S AF Kirova, N Brazovskii, S TI Combined topological defects in spin density waves and the NBN generation. SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE models of nonlinear phenomena; organic metals ID CURRENT CONVERSION PROBLEM; NOISE; CRYSTALS; SOLITONS AB The rich order parameter of Spin Density Waves allows for an unusual object of a complex topological nature: "Chimeras" composed by a half - integer dislocation combined with a semi - vortex of the staggered magnetization. They become energetically favorable due to enhanced Coulomb interactions. Their generation changes the NBN frequency. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Landau Inst, Moscow, Russia. RP Kirova, N (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. RI Brazovskii, Serguei/A-9608-2012 OI Brazovskii, Serguei/0000-0001-8147-9655 NR 15 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 103 IS 1-3 BP 1831 EP 1832 DI 10.1016/S0379-6779(98)00483-4 PG 2 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 210JN UT WOS:000081101500022 ER PT J AU Klehe, AK Honold, MM Nam, MS Harrison, N Mielke, C Inokuchi, M Sato, A Naito, T Kobayashi, A Kobayashi, H Singleton, J AF Klehe, AK Honold, MM Nam, MS Harrison, N Mielke, C Inokuchi, M Sato, A Naito, T Kobayashi, A Kobayashi, H Singleton, J TI High pressure and high field studies of alpha-[(CH3)(2)(C2H5)(2)N][Ni(dmit)(2)](2) SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE conductivity; magnetotransport; magnetic measurements; order-disorder phase transitions; organic conductor ID ELECTRONIC-STRUCTURES; CRYSTAL; METAL AB The magnetoresistance of alpha-[(CH3)(2)(C2H5)(2)N][Ni(dmit)(2)](2) has been studied at ambient pressure in magnetic fields of up to 60 T and under hydrostatic pressures of up to 6 kbar in fields of up to 17 T. The high field measurements indicate a very simple Fermi surface. Measurements in medium fields, however, indicate several quantum oscillation frequencies, whose weight gets reduced with increasing field in favour of the major gamma-orbit. The low field alpha- and beta-orbits exhibit a strong pressure sensitivity. Whereas no quantum oscillations were observed at 2 kbar, shifted alpha-and beta-frequencies occur at a pressure of 6 kbar. C1 Univ Oxford, Dept Phys, Clarendon Lab, Oxford OX1 3PU, England. Univ Calif Los Alamos Natl Lab, High Field Magnet Lab, Los Alamos, NM 87545 USA. Sci Univ Tokyo, Dept Mat Sci & Engn, Yamaguchi 756, Japan. Inst Mol Sci, Okazaki, Aichi 4448585, Japan. Hokkaido Univ, Fac Sci, Dept Chem, Sapporo, Hokkaido 0600810, Japan. Univ Tokyo, Sch Sci, Dept Chem, Tokyo 1130033, Japan. RP Klehe, AK (reprint author), Univ Oxford, Dept Phys, Clarendon Lab, Pk Rd, Oxford OX1 3PU, England. RI Mielke, Charles/S-6827-2016 OI Mielke, Charles/0000-0002-2096-5411 NR 4 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 103 IS 1-3 BP 1835 EP 1836 DI 10.1016/S0379-6779(98)00487-1 PG 2 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 210JN UT WOS:000081101500024 ER PT J AU Montgomery, LK Vestal, RM Starkey, KP Fravel, BW Samide, MJ Peters, DG Mielke, CH Thompson, JD AF Montgomery, LK Vestal, RM Starkey, KP Fravel, BW Samide, MJ Peters, DG Mielke, CH Thompson, JD TI Cu(II) incorporation in kappa-(ET)(2)Cu[N(CN)(2)]Br SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE organic superconductors; electrochemical methods; electrocrystallization AB Analyses of CuBr and CuN(CN)(2) used in the preparation of kappa-(ET)(2)Cu[N(CN)(2)]Br reveal both magnetic (1-42 ppm) and nonmagnetic (1-5%) contaminants. Markedly different resistivity profiles are obtained for kappa-(ET)(2)Cu[N(CN)(2)]Br samples prepared from various Cu(I) sources; some profiles show little or no resistive hump near 100 K. Rotating disk voltammetry studies indicate that the E-1/2 values for ET and the Cu[N(CN)(2)]Br anion are similar. Accordingly, considerable quantities of Cu(ll) must be produced during the electrochemical synthesis of kappa-(ET)(2)Cu[N(CN)(2)]Br. Whether Cu(ll) that is generated in this manner is incorporated into kappa-(ET)(2)Cu[N(CN)(2)]Br is under investigation. C1 Indiana Univ, Dept Chem, Bloomington, IN 47405 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Montgomery, LK (reprint author), Indiana Univ, Dept Chem, Bloomington, IN 47405 USA. RI Mielke, Charles/S-6827-2016 OI Mielke, Charles/0000-0002-2096-5411 NR 6 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 103 IS 1-3 BP 1878 EP 1879 DI 10.1016/S0379-6779(98)00580-3 PG 2 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 210JN UT WOS:000081101500039 ER PT J AU Dong, J Musfeldt, JL Schlueter, JA Williams, JM Gard, GL AF Dong, J Musfeldt, JL Schlueter, JA Williams, JM Gard, GL TI Optical properties of beta ''-(ET)(2)SF5CH2CF2SO3: A novel superconductor with large discrete counterions SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE reflection spectroscopy; organic superconductors ID ORGANIC SUPERCONDUCTORS; BEDT-TTF AB The optical spectra of the organic superconductor beta "-(ET)(2)SF5CH2CF2SO3 are measured over a wide spectral range (30-35000 cm(-1)) as a function of temperature and polarization. The optical anisotropy is quite large compared with other ET-based organic superconductors, and the spectra are far from Drude-like over the full temperature range. A broad electronic band centered near 1000 cm(-1) is observed at low temperature along the a axis, prior to the superconducting transition. The changes of vibrational features near 120 K are attributed to a weak reorientation of the counterion, which may affect hydrogen bonding in the material. C1 SUNY Binghamton, Dept Chem, Binghamton, NY 13902 USA. Argonne Natl Lab, Div Chem & Mat Sci, Argonne, IL 60439 USA. Portland State Univ, Dept Chem, Portland, OR 97207 USA. RP Dong, J (reprint author), SUNY Binghamton, Dept Chem, Binghamton, NY 13902 USA. NR 7 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 103 IS 1-3 BP 1892 EP 1893 DI 10.1016/S0379-6779(98)00595-5 PG 2 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 210JN UT WOS:000081101500047 ER PT J AU Nam, MS Honold, MM Proust, C Harrison, N Mielke, CH Blundell, SJ Singleton, J Hayes, W Kurmoo, M Day, P AF Nam, MS Honold, MM Proust, C Harrison, N Mielke, CH Blundell, SJ Singleton, J Hayes, W Kurmoo, M Day, P TI One-and two-dimensional angle-dependent magnetoresistance oscillations(AMROs) in kappa-(BEDT-TTF)(2)Cu(SCN)(2) in fields of up to 33 T SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE angle-dependent magnetoresistance oscillations; organic superconductors; magnetic breakdown; BEDT-TTF ID ORGANIC SUPERCONDUCTOR KAPPA-(BEDT-TTF)(2)CU(NCS)(2); MAGNETIC-FIELDS; FERMI-SURFACE; METALS; PRESSURE AB Angle-dependent magnetoresistance oscillations (AMROs) in kappa-(BEDT-TTF)(2)Cu(SCN)(2) have been observed in fields of up to 33 T. AMROs due to both open and closed Fermi surface sections have been measured simultaneously for the first time in an organic metal. This provides information concerning the low temperature Fermi surface and demonstrates the absence of a spin-density wave state in this material. C1 Univ Oxford, Dept Phys, Clarendon Lab, Oxford OX1 3PU, England. INSA, Serv Natl Champs Magnet Pulses, Phys Mat Condensee Lab, F-31077 Toulouse, France. Univ Calif Los Alamos Natl Lab, Natl High Magnet Field Lab, Los Alamos, NM 87545 USA. Royal Inst, London W1X 4BC, England. RP Nam, MS (reprint author), Univ Oxford, Dept Phys, Clarendon Lab, Parks Rd, Oxford OX1 3PU, England. RI Mielke, Charles/S-6827-2016 OI Mielke, Charles/0000-0002-2096-5411 NR 12 TC 14 Z9 14 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 103 IS 1-3 BP 1905 EP 1906 DI 10.1016/S0379-6779(98)00607-9 PG 2 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 210JN UT WOS:000081101500054 ER PT J AU Singleton, J Honold, MM Harrison, N Nam, MS Mielke, CH Kartsovnik, MV Kushch, ND AF Singleton, J Honold, MM Harrison, N Nam, MS Mielke, CH Kartsovnik, MV Kushch, ND TI Hall potential oscillations in alpha-(BEDT-TTF)(2)TlHg(SCN)(4) SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE quantum oscillations; BEDT-TTF salts; quantum Hall effect; Corbino geometry ID MAGNETIC-FIELDS; ORGANIC METALS; QUANTUM; ALPHA-(BEDT-TTF)(2)KHG(SCN)(4); STATES AB Direct measurements of the Hall potential in alpha-(BEDT-TTF)(2)T1Hg(SCN)(4), a material thought to exhibit the quantum Hall effect, have been made using a variant of the Corbino technique in fields of up to 60 T. This method, in which the Hall voltage is proportional to the ratio of the resistivities rho(xy)/rho(parallel to) provides a novel way of investigating quantum oscillations. C1 Univ Oxford, Clarendon Lab, Oxford OX1 3PU, England. Univ Calif Los Alamos Natl Lab, Natl High Magnet Field Lab, Los Alamos, NM 87545 USA. Walther Meissner Inst Tieftemp Forsch, D-85748 Garching, Germany. Russian Acad Sci, Inst Solid State Phys, Chernogolovka 142432, MD, Russia. RP Singleton, J (reprint author), Univ Oxford, Clarendon Lab, Parks Rd, Oxford OX1 3PU, England. RI Kartsovnik, Mark/E-3598-2013; Mielke, Charles/S-6827-2016 OI Kartsovnik, Mark/0000-0002-3011-0169; Mielke, Charles/0000-0002-2096-5411 NR 11 TC 0 Z9 0 U1 0 U2 2 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 103 IS 1-3 BP 1953 EP 1954 DI 10.1016/S0379-6779(98)00878-9 PG 2 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 210JN UT WOS:000081101500078 ER PT J AU Wosnitza, J Wanka, S Qualls, JS Brooks, JS Mielke, CH Harrison, N Schlueter, JA Williams, JM Nixon, PG Winter, RW Gard, GL AF Wosnitza, J Wanka, S Qualls, JS Brooks, JS Mielke, CH Harrison, N Schlueter, JA Williams, JM Nixon, PG Winter, RW Gard, GL TI Fermiology of the organic superconductor beta ''-(ET)(2)SF5CH2CF2SO3 SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE organic superconductors; magnetic measurements; transport measurements ID MAGNETORESISTANCE AB We present a detailed Fermi-surface (FS) investigation of the quasi two-dimensional (2D) organic superconductor (T-c = 4.5 K) beta "-(ET)(2)SF5CH2CF2SO3. In line with previous investigations, de Haas-van Alphen measurements in pulsed fields up to 60 T show a single oscillation frequency, F-0 = 200 T, which corresponds to a FS size of about 5% of the first Brillouin zone. Angular dependent magnetoresistance oscillations (AMROs) are utilized for the exact determination of the in-plane FS, which is found to be a strongly elongated ellipsoid with an axes ratio of about 1:9. Transport measurements in static fields up to 33 T show an unusual temperature dependence of the Shubnikov-de Haas (SdH) signal, i.e., a decrease of the SdH amplitude with decreasing temperature. C1 Univ Karlsruhe, Inst Phys, D-76128 Karlsruhe, Germany. Florida State Univ, Natl High Magnet Field Lab, Tallahassee, FL 32306 USA. LANL, Natl High Magent Field Lab, Los Alamos, NM 87545 USA. Argonne Natl Lab, Div Chem & Mat Sci, Argonne, IL 60439 USA. Portland State Univ, Dept Chem, Portland, OR 97207 USA. RP Wosnitza, J (reprint author), Univ Karlsruhe, Inst Phys, Engesserstr 7, D-76128 Karlsruhe, Germany. RI Mielke, Charles/S-6827-2016 OI Mielke, Charles/0000-0002-2096-5411 NR 7 TC 22 Z9 22 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 103 IS 1-3 BP 2000 EP 2001 DI 10.1016/S0379-6779(98)00920-5 PG 2 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 210JN UT WOS:000081101500105 ER PT J AU Honold, MM Harrison, N Mielke, CH Singleton, J Bennett, MC Kurmoo, M Day, P AF Honold, MM Harrison, N Mielke, CH Singleton, J Bennett, MC Kurmoo, M Day, P TI Quantum oscillations in alpha-(BEDT-TTF)(2)KHg(SCN)(4) above the Neel temperature SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE BEDT-TTF salts; Shubnikov-de Haas oscillations; spin-density wave ID ORGANIC CONDUCTOR ALPHA-(BEDT-TTF)(2)KHG(SCN)(4); MAGNETIC-FIELDS; STATE; MAGNETOTRANSPORT; PHASE AB We have performed measurements of the interplane magnetoresistance of alpha-(BEDT-TTF)(2)KHg(SCN)(4) in pulsed magnetic fields of up to 60 T and temperatures up to 13 K. Shubnikov-de Haas (SdH) oscillations are observed well above the Neel temperature of T-N similar to 8 K which indicates the destruction of antiferromagnetic ordering. This enables the study of a sector of the phase diagram which has thus far not been accessible to fermiological techniques. C1 Univ Oxford, Dept Phys, Clarendon Lab, Oxford OX1 3PU, England. Univ Calif Los Alamos Natl Lab, Natl High Magnet Field Lab, Los Alamos, NM 87545 USA. Royal Inst, London W1X 4BS, England. RP Honold, MM (reprint author), Univ Oxford, Dept Phys, Clarendon Lab, Parks Rd, Oxford OX1 3PU, England. RI Mielke, Charles/S-6827-2016 OI Mielke, Charles/0000-0002-2096-5411 NR 15 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 103 IS 1-3 BP 2048 EP 2049 DI 10.1016/S0379-6779(98)00401-9 PG 2 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 210JN UT WOS:000081101500124 ER PT J AU Brooks, JS O'Brien, JL Starrett, RP Clark, RG Han, SY Qualls, JS Takasaki, S Yamada, J Anzai, H Mielke, CH Montgomery, LK Rutel, IB AF Brooks, JS O'Brien, JL Starrett, RP Clark, RG Han, SY Qualls, JS Takasaki, S Yamada, J Anzai, H Mielke, CH Montgomery, LK Rutel, IB TI L-K treatment of the SdH oscillations in the SDW state of Q1D materials SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE organic charge transfer salts; high field magnetotransport; quantum oscillations ID MAGNETORESISTANCE AB We have applied Lifshitz-Kosevich theory to directly fit the high field oscillatory magnetoresistance in the Q-1-dimensional Bechgaard salts in (TMTSF)(2)X (X = AsF(6) or ClO(4)[Q-state]) in their spin density wave states. Values of m* Dingle temperature, and SdH frequencies are obtained, and the anomalous temperature dependence of the oscillation amplitudes are discussed. C1 Univ New S Wales, Sch Phys, Dept Phys, Tallahassee, FL 32310 USA. Univ New S Wales, Sch Phys, Natl Pulsed Magnet Lab, Sydney, NSW 2052, Australia. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Indiana Univ, Dept Chem, Bloomington, IN 47405 USA. Worcester Polytech Inst, Dept Phys, Worcester, MA 01609 USA. RP Brooks, JS (reprint author), Univ New S Wales, Sch Phys, Dept Phys, Tallahassee, FL 32310 USA. RI O'Brien, Jeremy/A-6290-2008; Mielke, Charles/S-6827-2016; OI Mielke, Charles/0000-0002-2096-5411; O'Brien, Jeremy/0000-0002-3576-8285 NR 5 TC 1 Z9 1 U1 0 U2 2 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 103 IS 1-3 BP 2054 EP 2055 DI 10.1016/S0379-6779(98)00407-X PG 2 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 210JN UT WOS:000081101500127 ER PT J AU Lin, Y Eldridge, JE Wang, HH Kini, AM Kelly, ME Williams, JM Schlueter, J AF Lin, Y Eldridge, JE Wang, HH Kini, AM Kelly, ME Williams, JM Schlueter, J TI The effect of spin fluctuations on two phonons lines in the Raman scattering from (ET)(2)Cu (NCS)(2) SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE Raman spectroscopy; organic conductors; magnetic phase transitions ID ORGANIC SUPERCONDUCTORS; AMBIENT PRESSURE; KAPPA-(BEDT-TTF)2CU(NCS)2; ANOMALIES AB The temperature-dependence of the intensity and frequency of two intense features in the Raman spectrum of x-(BEDT-TTF)(2)[Cu(NCS)(2)] have been measured. The frequencies of these modes were observed to soften below 80K, in the temperature range where antiferromagnetic fluctuations have been observed, providing evidence of interactions between the phonons and the magnetism. C1 Univ British Columbia, Dept Phys & Astron, Vancouver, BC V6T 1Z1, Canada. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Argonne Natl Lab, Div Sci Mat, Argonne, IL 60439 USA. RP Lin, Y (reprint author), Univ British Columbia, Dept Phys & Astron, Vancouver, BC V6T 1Z1, Canada. RI Kini, Aravinda/F-4467-2012 NR 15 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 103 IS 1-3 BP 2071 EP 2072 DI 10.1016/S0379-6779(98)00423-8 PG 2 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 210JN UT WOS:000081101500136 ER PT J AU Honold, MM Harrison, N Nam, MS Singleton, J Mielke, CH Kurmoo, M Day, P AF Honold, MM Harrison, N Nam, MS Singleton, J Mielke, CH Kurmoo, M Day, P TI Magnetic breakdown in the high-field phase of the organic conductor alpha-(BEDT-TTF)(2)KHg(SCN)(4) SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE BEDT-TTF salts; de Haas-van Alphen effect; quantum Hall effect; spin-density wave ID LOW-TEMPERATURE STATE; ELECTRONIC-STRUCTURE; DEPENDENCE AB Measurements of the magnetic susceptibility in alpha-(BEDT-TTF)(2)KHg(SCN)(4) in fields of up to 60 T show that the magnetic breakdown beta frequency persists and is not attenuated on passing through the kink transition. A quantitative analysis of the oscillation amplitude over a wide range of field shows that the energy gap between the quasi-one- and two-dimensional parts of the Fermi surface is much smaller than previously estimated. We discuss the implications of this for the spin-density-wave nesting and the quantum Hall effect. C1 Univ Oxford, Clarendon Lab, Dept Phys, Oxford OX1 3PU, England. Los Alamos Natl Lab, Natl High Magnet Field Lab, Los Alamos, NM 87545 USA. UCL Royal Inst Great Britain, London W1X 4BS, England. RP Honold, MM (reprint author), Univ Oxford, Clarendon Lab, Dept Phys, Pk Rd, Oxford OX1 3PU, England. RI Mielke, Charles/S-6827-2016 OI Mielke, Charles/0000-0002-2096-5411 NR 16 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 103 IS 1-3 BP 2093 EP 2094 DI 10.1016/S0379-6779(98)00451-2 PG 2 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 210JN UT WOS:000081101500150 ER PT J AU Pedron, D Bozio, R Schlueter, JA Kelly, ME Kini, AM Williams, JM AF Pedron, D Bozio, R Schlueter, JA Kelly, ME Kini, AM Williams, JM TI Electron-phonon coupling in kappa-(BEDT-TTF)(2)Cu(NCS)(2) organic superconductor studied by Raman scattering spectroscopy SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE organic superconductors; infrared and Raman spectroscopy; superconducting phase transitions ID T-C; KAPPA-(ET)(2)CU(NCS)(2); DEPENDENCE; DONOR AB Low frequency Raman data for kappa-(ET)(2)Cu(NCS)(2) (T-c = 10.4 K) are reported. Measurements have been performed in a wide range of temperatures (1.5 - 100 K) and frequency hardening related to the superconducting transition has been observed for all the low-lying coupled phonons. The measured relative frequency shifts are lower than those previously reported for kappa-(ET)(2)Cu[N(CN)(2)]Br (T-c=11.6 K), but the behavior of the two systems is similar and indicates a significant strength of the intermolecular electron-phonon coupling. The effects of isotopic substitutions ((C4S8)-C-13-S-34 and H-2(8)) in ET molecules on the low frequency Raman active phonons of kappa-(ET)(2)Cu(NCS)(2) are also reported. They give the first direct experimental confirmation to the suggested lattice softening induced by deuteration. C1 Univ Padua, Dept Chem Phys, I-35131 Padua, Italy. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Argonne Natl Lab, Div Sci Mat, Argonne, IL 60439 USA. RP Pedron, D (reprint author), Univ Padua, Dept Chem Phys, Via Loredan 2, I-35131 Padua, Italy. RI Bozio, Renato/E-9066-2012; Kini, Aravinda/F-4467-2012 OI Bozio, Renato/0000-0001-7274-9190; NR 15 TC 10 Z9 10 U1 1 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 103 IS 1-3 BP 2220 EP 2223 DI 10.1016/S0379-6779(98)00303-8 PG 4 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 210JN UT WOS:000081101500216 ER PT J AU Launois, P Moret, R Llusca, E Hone, J Zettl, A AF Launois, P Moret, R Llusca, E Hone, J Zettl, A TI Polymer chain orientations in KC60 and RbC60: Structural analysis and relation with electronic properties SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE fullerenes and derivatives; X-ray diffraction and scattering; computer simulations ID SOLID C-60; RB-87 NMR; RB; PRESSURE; AC(60); RB1C60; RB3C60; A=K; CS; DIFFRACTION AB First single crystal X-ray diffraction studies of polymerized KC60 and RbC60 are presented. While powder diffraction studies showed no definite structural differences, the single crystal diffraction data analysis reveals different relative chain orientations in the two compounds. They are discussed in relation with semi-empirical energy calculations. The structural difference between KC60 and RbC60 may be a key feature for the understanding of their contrasted conducting and magnetic properties. C1 Univ Paris Sud, Phys Solides Lab, CNRS, URA 002, F-91405 Orsay, France. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Launois, P (reprint author), Univ Paris Sud, Phys Solides Lab, CNRS, URA 002, Bat 510, F-91405 Orsay, France. RI Hone, James/E-1879-2011; Zettl, Alex/O-4925-2016 OI Hone, James/0000-0002-8084-3301; Zettl, Alex/0000-0001-6330-136X NR 35 TC 10 Z9 10 U1 0 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 103 IS 1-3 BP 2354 EP 2357 DI 10.1016/S0379-6779(98)00237-9 PG 4 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 210JN UT WOS:000081101500271 ER PT J AU Kirova, N Firlej, L Zahab, A AF Kirova, N Firlej, L Zahab, A TI Fullerenes dissolve gold in a sequence of phase transformations SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE Fullerenes and derivatives; polycrystalline thin films ID C-60 THIN-FILMS; DIFFUSION AB We present the observation of gold intercalation into the polycrystalline C-60 and C-70 thin films by a dry electrolysis of the electrode, detected by in situ and space resolved conductivity measurements at different temperatures and applied voltages. The time resistivity behavior is described on the basis of electric field stimulated diffusion of metal ions from the contact into the interstitials of crystal lattice. The resistivity minima correspond to a local formation of Au3C60 and respectively Au1C70 and Au4C70 phases. In contrast to AuxC60, the AuxC70 phases are stable only in the applied electric field. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Montpellier 2, Dynam Phases Condensees Grp, F-34095 Montpellier, France. RP Kirova, N (reprint author), Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 103 IS 1-3 BP 2456 EP 2457 DI 10.1016/S0379-6779(98)00704-8 PG 2 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 210JN UT WOS:000081101500316 ER PT J AU Hone, J Whitney, M Zettl, A AF Hone, J Whitney, M Zettl, A TI Thermal conductivity of single-walled carbon nanotubes SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE heat conduction; fullerenes and derivatives AB We have measured the thermal conductivity (kappa) of bulk samples of single-walled nanotube (SWNT) bundles. The thermal conductivity of SWNT's is found to be large, and dominated by phonons at all temperatures. kappa(T) Of SWNT's is linear in temperature from 7 K to 25 K, increases slope between 25 K and 40 K, and rises monotonically with temperature to above room temperature. The data call be fit by a single-scattering-time model; the model confirms that the low-temperature linear behavior is due to the thermal conductivity of a single one-dimensional phonon subband, and that the phonon mean free path is of order 100 nm. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Sci Mat, Berkeley, CA 94720 USA. RP Hone, J (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Hone, James/E-1879-2011; Zettl, Alex/O-4925-2016 OI Hone, James/0000-0002-8084-3301; Zettl, Alex/0000-0001-6330-136X NR 4 TC 142 Z9 143 U1 3 U2 34 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 103 IS 1-3 BP 2498 EP 2499 DI 10.1016/S0379-6779(98)01070-4 PG 2 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 210JN UT WOS:000081101500333 ER PT J AU Fuhrer, MS Holmes, W Richards, PL Delaney, P Louie, SG Zettl, A AF Fuhrer, MS Holmes, W Richards, PL Delaney, P Louie, SG Zettl, A TI Nonlinear transport and localization in single-walled carbon nanotubes SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE transport measurements; conductivity; Hall effect; magnetotransport; Fullerenes and derivatives ID RANGE-HOPPING REGIME; CRYSTALLINE ROPES; CONDUCTIVITY; CONDUCTORS; TUBULES AB We have measured the electrical transport properties of mats of single-walled carbon nanotubes (SWNT) as a function of applied electric and magnetic fields. We find that at low temperatures the resistance as a function of temperature R(T) follows the Mott variable range hopping (VRH) formula for hopping in three dimensions. Measurement of the electric field dependence of the resistance R(E) allows for the determination of the Bohr radius of a localized state a = 700nm. The magnetoresistance (MR) of SWNT mat samples is large and negative at all temperatures and fields studied. The low field negative MR is proportional to H-2, in agreement with variable range hopping in two or three dimensions. 3D VRH indicates good intertube contacts, implying that the localization is due to the disorder experienced by the individual tubes, The 3D localization radius gives a measure of the 1D localization length on the individual tubes, which we estimate to be >700 nm. Implications for the electron-phonon mean free path are discussed. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Fuhrer, MS (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Fuhrer, Michael/E-7634-2010; Zettl, Alex/O-4925-2016 OI Fuhrer, Michael/0000-0001-6183-2773; Zettl, Alex/0000-0001-6330-136X NR 16 TC 38 Z9 38 U1 1 U2 11 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 103 IS 1-3 BP 2529 EP 2532 DI 10.1016/S0379-6779(98)00305-1 PG 4 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 210JN UT WOS:000081101500348 ER PT J AU Brazovskii, S Kirova, N AF Brazovskii, S Kirova, N TI Plastic sliding, strained states and current conversion in Density Waves. SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE models of nonlinear phenomena; X-ray emission; diffraction; and scattering ID PHASE-SLIP; CHARGE; CRYSTALS; NBSE3; DEFORMATIONS; CONDUCTION; GENERATION; VORTICES; SOLITONS; NOISE AB We outline a theory of coexisting elastic and plastic deformations in sliding Charge Density Waves. They occur in the course of the conversion from the normal current at the contact to the collective one in the bulk. Several mechanisms of phase slips via creation and proliferation of dislocations are compared. We present a modeling which helps to interpret space-resolved studies in recent [1] and earlier [2] X-ray experiments, in multi-contact [3] and optical [4] studies. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Landau Inst, Moscow, Russia. RP Brazovskii, S (reprint author), Brookhaven Natl Lab, Dept Phys, Bld 510A, Upton, NY 11973 USA. RI Brazovskii, Serguei/A-9608-2012 OI Brazovskii, Serguei/0000-0001-8147-9655 NR 26 TC 3 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 103 IS 1-3 BP 2589 EP 2592 DI 10.1016/S0379-6779(98)00266-5 PG 4 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 210JN UT WOS:000081101500369 ER PT J AU Bardeau, JF Eberhardt, AS Scott, B Billinge, S Kycia, S Egami, T Swanson, BI AF Bardeau, JF Eberhardt, AS Scott, B Billinge, S Kycia, S Egami, T Swanson, BI TI Recent structural studies of PtI SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE X-ray diffraction; structural phase transition AB The halogen-bridged mixed-valence metal complexes (MX) have been the object of numerous studies probing the properties of their quasi-one-dimensional M-X sublattice in which the charge disproportionation delta of the metal (M3-delta/M3+delta) can be tuned from 0 to 1. We have recently investigated the structure of a fully deuterated sample of [Pt(en)(2)][Pt(en)(2)I-2](ClO4)(4) at room temperature by using pair-distribution-function analysis X-ray powder diffraction data and regular single crystal diffraction in order to study the relationship between the local structure and the charge density wave strength of this class of materials. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Michigan State Univ, CFMR, DPA, E Lansing, MI 48824 USA. Cornell Univ, CHESS, Ithaca, NY USA. Univ Penn, LRSM, DMSE, Philadelphia, PA 19104 USA. RP Bardeau, JF (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Scott, Brian/D-8995-2017 OI Scott, Brian/0000-0003-0468-5396 NR 12 TC 0 Z9 0 U1 0 U2 2 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 103 IS 1-3 BP 2596 EP 2597 DI 10.1016/S0379-6779(98)00655-9 PG 2 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 210JN UT WOS:000081101500371 ER PT J AU Hill, S Brooks, JS Uji, S Takashita, M Terakura, C Terashima, T Aoki, H Fisk, Z Sarrao, J AF Hill, S Brooks, JS Uji, S Takashita, M Terakura, C Terashima, T Aoki, H Fisk, Z Sarrao, J TI Bulk quantum Hall effect in eta-Mo4O11 SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE magnetotransport; Hall effect; superlattices ID TRANSPORT-PROPERTIES; SURFACE-STATES; HIGH-FIELD; CRYSTALS AB We have observed a quantum Hall effect in the bulk quasi-two-dimensional conductor eta-Mo4O11 The Hall resistance exhibits well defined plateaux, coincident with pronounced minima in the diagonal resistance. We present data for several different samples and contact geometries, and discuss a possible mechanism for the quantum Hall effect in this system. We also discuss the implications of these findings in the light of recent predictions concerning chiral metallic surface states in bulk quantum Hall systems. C1 Montana State Univ, Dept Phys, Bozeman, MT 59717 USA. Natl High Magnet Field Lab, Tallahassee, FL 32310 USA. Natl Res Inst Met, Ibaraki 305, Japan. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Hill, S (reprint author), Montana State Univ, Dept Phys, Bozeman, MT 59717 USA. RI Terakura, Chieko/A-5959-2009; Hill, Stephen/J-5383-2014 OI Hill, Stephen/0000-0001-6742-3620 NR 17 TC 1 Z9 1 U1 0 U2 5 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 103 IS 1-3 BP 2667 EP 2670 DI 10.1016/S0379-6779(98)00211-2 PG 4 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 210JN UT WOS:000081101500398 ER PT J AU Cadby, AJ Partee, J Shinar, J Martin, SJ Bradley, DDC Lane, PA AF Cadby, AJ Partee, J Shinar, J Martin, SJ Bradley, DDC Lane, PA TI Optically detected magnetic resonance studies of tetrathienylene vinylene SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE optically detected magnetic resonance; polarons; triplet excitons; conjugated polymer AB We have investigated films and dilute glasses of tetrathienylene vinylene (4TV) by optically detected magnetic resonance. We calculate the g-values of polarons and zero field splitting parameters for triplet excitons. The strength of the ODMR signals, but not their spectral lineshapes, are sensitive to the sample concentration. Photoexcitation lifetimes were also estimated. C1 Univ Sheffield, Dept Phys, Sheffield S3 7RH, S Yorkshire, England. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Cadby, AJ (reprint author), Univ Sheffield, Dept Phys, Sheffield S3 7RH, S Yorkshire, England. RI Bradley, Donal/F-6068-2011; Martin, Simon Martin/H-1431-2011; Cadby, Ashley/H-3679-2013 OI Bradley, Donal/0000-0001-8713-5060; Cadby, Ashley/0000-0002-5472-8625 NR 3 TC 1 Z9 1 U1 0 U2 5 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 102 IS 1-3 BP 926 EP 927 DI 10.1016/S0379-6779(98)00961-8 PG 2 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 209PF UT WOS:000081056400027 ER PT J AU Yu, ZG Smith, DL Saxena, A Bishop, AR AF Yu, ZG Smith, DL Saxena, A Bishop, AR TI Dynamics of electronic transmission in metal/organic/metal structures SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE models of surface and interface chemistry and physics ID SELF-ASSEMBLED MONOLAYERS; ORGANIC THIN-FILMS AB We study the dynamics of electronic transport across a metal/conjugated-oligomer/metal structure using a novel self-consistent Green's function approach developed recently. We find a crossover from the free electron-like to polaron-like behavior in transport with increasing phonon frequency of the oligomer. These results have implications for transport experiments on polymer light-emitting diodes and molecular wires. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Yu, ZG (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 9 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 102 IS 1-3 BP 1057 EP 1058 DI 10.1016/S0379-6779(98)01342-3 PG 2 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 209PF UT WOS:000081056400091 ER PT J AU List, EJW Partee, J Graupner, W Shinar, J Leising, G AF List, EJW Partee, J Graupner, W Shinar, J Leising, G TI Excitation energy transfer in guest host systems studied by magnetic resonance techniques SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE poly(paraphenylene); optical emission spectroscopy; excitation energy transfer; optically detected magnetic resonance ID LIGHT-EMITTING-DIODES; CONJUGATED POLYMERS; DYNAMICS; POLARONS; ORANGE; WHITE; BLUE AB Blending the conjugated ladder-type poly(paraphenylene) (LPPP) with small amounts of the red emitting poly(perylene-codiethynylbenzene) (PPDB), shifts the photoluminescence emission of the blends from blue to red due to an efficient excitation energy transfer (EET) of singlet excitons. We used the spin sensitive technique of photoluminescence detected magnetic resonance to monitor interchain polaron pairs and triplet excitons involved in the EET in differently concentrated m-LPPP/PPDB blends and in the pristine polymers. Polaron pairs and triplet excitons in PPDB and LPPP are distinct in their magnetic resonance signatures while the singlet excitons are distinct in their spectral emission position. C1 Graz Tech Univ, Inst Festkorperphys, A-8010 Graz, Austria. Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA. RP List, EJW (reprint author), Graz Tech Univ, Inst Festkorperphys, Petersgasse 16, A-8010 Graz, Austria. RI List-Kratochvil, Emil/M-5312-2013 NR 13 TC 1 Z9 1 U1 0 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 102 IS 1-3 BP 1077 EP 1078 DI 10.1016/S0379-6779(98)01367-8 PG 2 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 209PF UT WOS:000081056400101 ER PT J AU Zojer, E Markart, P List, EJW Graupner, W Smith, R Leising, G Shinar, J Gin, D AF Zojer, E Markart, P List, EJW Graupner, W Smith, R Leising, G Shinar, J Gin, D TI Photophysical properties of nanostructured PPV-composites SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE superlattices; poly (phenylene vinylene) and derivatives; optical absorption and emission spectroscopy; optically detected magnetic resonance ID POLYMERS; POLARONS AB We present photophysical properties, like spectral line-shape and site selectivity of photoluminescence (PL) PL quantum yields and Optically Detected Magnetic Resonance (ODMR) responses of bulk poly(para-phenylenevinylene) films and isolated PPV chains incorporated into a self-assembled matrix ordered at a nanometer scale. The ordering is a result of the lyotropic liquid-crystalline character of the matrix material, which leads to the formation of a regular hexagonal array of channels with a diameter of about 15 Angstrom, in which the conjugated polymer chains are contained. The structure of the nanocomposite is confirmed by X-ray diffraction analysis. C1 Graz Tech Univ, Inst Festkorperphys, A-8010 Graz, Austria. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Iowa State Univ Sci & Technol, Ames Lab, US DOE, Ames, IA 50011 USA. RP Zojer, E (reprint author), Graz Tech Univ, Inst Festkorperphys, Petersgasse 16, A-8010 Graz, Austria. RI Zojer, Egbert/B-3265-2010; List-Kratochvil, Emil/M-5312-2013; OI Zojer, Egbert/0000-0002-6502-1721; GIN, DOUGLAS/0000-0002-6215-668X NR 7 TC 6 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 102 IS 1-3 BP 1270 EP 1271 DI 10.1016/S0379-6779(98)01467-2 PG 2 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 209PF UT WOS:000081056400198 ER PT J AU Wang, HL Mattes, BR AF Wang, HL Mattes, BR TI Gas transport and sorption in polyaniline thin film SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE polyaniline; solution processing; permeability ID POLYMERS AB The permeability of gases through thin polyaniline EB film depends upon the combined mobility and solubility of the gases at a given temperature and pressure. The gas transport behavior of an emeraldine base (EB) film was studied in detail. Permeability measurements were made using the manometric time-lag method of analysis for He, H-2' CO2, O-2, N-2 and CH4, all as functions of varying temperature (15 degrees to 40 degrees C). These measurements allowed us to determine the activation energies for permeation, diffusion, and heat of solution for each gas tested. Permeability of the gases is temperature dependent, permeability increases with increasing temperature and permselectivity of the gas pairs He/N-2, O-2/N-2, CO2/CH4 decreases with increasing temperature. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Wang, HL (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. NR 9 TC 18 Z9 21 U1 1 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 102 IS 1-3 BP 1333 EP 1334 DI 10.1016/S0379-6779(98)01057-1 PG 2 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 209PF UT WOS:000081056400232 ER PT J AU Bardeau, JF Eberhardt, AS Nyquist, RM Parikh, AN Shreve, AP Swanson, BI AF Bardeau, JF Eberhardt, AS Nyquist, RM Parikh, AN Shreve, AP Swanson, BI TI Phase-transition based transduction in a biosensor SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE micelles and solution self-assembly; optical absorption; atomic force microscopy; infrared spectroscopy ID MEMBRANES; BINDING; GANGLIOSIDES; BILAYERS AB Shifts in the main phase transition temperatures caused by a highly specific, protein-receptor interaction in a hybrid bilayer architecture are probed utilizing temperature programmed infrared vibrational spectroscopy. The specific case of cholera toxin attachment to glycolipid receptors embedded in a phospholipid outer layer at a hydrophobized silicon surface is, investigated. Potential applications of the approach as a signal amplification method in biosensor will be discussed. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Bardeau, JF (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663,CST-1,MS G755, Los Alamos, NM 87545 USA. RI PARIKH, ATUL/D-2243-2014 OI PARIKH, ATUL/0000-0002-5927-4968 NR 12 TC 1 Z9 1 U1 0 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 102 IS 1-3 BP 1452 EP 1453 DI 10.1016/S0379-6779(98)00509-8 PG 2 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 209PF UT WOS:000081056400280 ER PT J AU Wang, HH Geiser, U Schlueter, JA Ward, BH Parakka, JP Kini, AM O'Malley, JL Thomas, SY Morales, E Dudek, JD Williams, JM Gard, GL AF Wang, HH Geiser, U Schlueter, JA Ward, BH Parakka, JP Kini, AM O'Malley, JL Thomas, SY Morales, E Dudek, JD Williams, JM Gard, GL TI Novel sulfonate containing ET based synmetals SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 98) CY JUL 12-18, 1998 CL MONTPELLIER, FRANCE DE electrocrystallization; BEDT-TTF; x-ray diffraction; ESR; transport measurement; Raman spectroscopy ID BEDT-TTF; SUPERCONDUCTIVITY; BIS(ETHYLENEDITHIO)TETRATHIAFULVALENE; TEMPERATURE; TRANSITION AB Electrocrystallization of ET in the presence of aromatic and aliphatic sulfonate anions has led to: many new ET salts. These new ET based sulfonate complexes are characterized with use of x-ray diffraction, four-probe conductivity measurements, ESR and Raman spectroscopies. A new kappa(4x4) donor packing motif was observed in (ET)(2)(C6H5CH2SO3)(H2O). Strong hydrogen bonding between the sulfonate anion S-O and the donor ethylene C-H provides the driving force for the ET salt formation, Many of these new sulfonate salts are highly conductive with some remaining metallic to similar to 4 K. C1 Argonne Natl Lab, Chem & Mat Sci Div, Argonne, IL 60439 USA. Portland State Univ, Dept Chem, Portland, OR 97207 USA. RP Wang, HH (reprint author), Argonne Natl Lab, Chem & Mat Sci Div, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Kini, Aravinda/F-4467-2012; OI Thomas, Seddon/0000-0003-0075-0744 NR 13 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN PY 1999 VL 102 IS 1-3 BP 1666 EP 1669 PG 4 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 209PF UT WOS:000081056400383 ER PT J AU Aida, M Yamataka, H Dupuis, M AF Aida, M Yamataka, H Dupuis, M TI Ab initio MD simulations of a prototype of methyl chloride hydrolysis with explicit consideration of three water molecules: a comparison of MD trajectories with the IRC path SO THEORETICAL CHEMISTRY ACCOUNTS LA English DT Article DE ab initio molecular dynamics; hydrolysis; intrinsic reaction coordinate; proton transfer; solvent effect; methyl chloride ID SELF-CONSISTENT-FIELD; DYNAMICS SIMULATIONS; REACTION COORDINATE; POTENTIALS; CLUSTERS; LI-8 AB Ab initio molecular dynamics simulations at the Hartree-Fock/6-31G level of theory are performed on methyl chloride hydrolysis with explicit consideration of one solute and two solvent water molecules at a temperature of 298 K. The reaction involves the formation of a reactant complex and the energy surface to the transition state is found to be simple. Two types of trajectories toward the product are observed. In the first type, the system reaches an intermediate complex (complex-P1) region after two nearly concerted proton transfers involving the attacking water molecule and the solvent water molecules. These trajectories resemble the intrinsic reaction coordinate trajectory. The thermal motion of the atoms leads the system to another intermediate complex (complex-P2) region. A second type of trajectory is found in which the system reaches the complex-P2 region directly after the proton transfers, In both of these forward trajectories, back proton transfers lead the system to a final complex-F region which resembles protonated methanol. C1 Hiroshima Univ, Fac Sci, Dept Chem, Higashihiroshima 7398526, Japan. Osaka Univ, Inst Sci & Ind Res, Ibaraki, Osaka 5670047, Japan. Pacific NW Natl Lab, EMLS, K1 83, Richland, WA 99352 USA. RP Aida, M (reprint author), Hiroshima Univ, Fac Sci, Dept Chem, 1-3 Kagamiyama, Higashihiroshima 7398526, Japan. RI Aida, Misako/D-1670-2010 OI Aida, Misako/0000-0001-8788-1071 NR 27 TC 17 Z9 17 U1 1 U2 5 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1432-881X J9 THEOR CHEM ACC JI Theor. Chem. Acc. PD JUN PY 1999 VL 102 IS 1-6 BP 262 EP 271 DI 10.1007/s002140050497 PG 10 WC Chemistry, Physical SC Chemistry GA 210UP UT WOS:000081123300033 ER PT J AU Gao, Y AF Gao, Y TI In-situ IR and spectroscopic ellipsometric analysis of growth process and structural properties of Ti1-xNbxO2 thin films by metal-organic chemical vapor deposition SO THIN SOLID FILMS LA English DT Article DE spectroscopic ellipsometry; oxides; metal-organic chemical vapour deposition; titanium ID MOLECULAR-BEAM EPITAXY; DOPED TIO2; TIO2(110); MOCVD; NB2O5 AB The formation process of Ti1-xNbxO2 films with the Nb concentration up to 38 at.% by metal-organic chemical vapor deposition (MOCVD) using titanium tetraisopropoxide (TTIP) and pentaethoxy niobium (PEN) as precursors has been characterized by In-situ Fourier transform IR (FTIR) spectroscopy and spectroscopic ellipsometry. Ln-situ FTIR data suggested that there was no gas phase decomposition of TTIP near the substrate surface under typical growth conditions. Post-deposition analysis of In-situ ellipsometric data allowed simultaneous determination of film thickness, growth rate, and refractive index of the films. Growth mode and surface roughness were also obtained in the post-deposition analysis. The growth process of Ti1-xNbxO2 films can be divided into three stages: nucleation and coalescence, the homogeneous growth, and the surface roughness evolution. Increase of the growth temperature appears to increase the initial island size, and decrease the outer rough surface layer. X-ray photoelectron spectroscopy revealed that the oxidation state of Ti and Nb is 4+. The structure of the Ti1-xNbxO2 films strongly depends on the growth temperature but not on the Nb concentration. The Ti1-xNbxO2 films deposited at 400 degrees C are pure anatase, a;nd at 800 degrees C are pure rutile, but show a mixture of anatase and rutile at the temperature range from 550 degrees C to 800 degrees C. Such a phase change in the films results in a large range of refractive index for the Ti1-xNbxO2 films. (C) 1999 Published by Elsevier Science Ltd. All rights reserved. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Gao, Y (reprint author), Pacific NW Natl Lab, POB 999,MS K8-93, Richland, WA 99352 USA. NR 24 TC 24 Z9 24 U1 0 U2 11 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD JUN 1 PY 1999 VL 346 IS 1-2 BP 73 EP 81 DI 10.1016/S0040-6090(98)01431-X PG 9 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 208YE UT WOS:000081019400003 ER PT J AU Rieker, T Hubbard, P Majewski, J Smith, G Moody, N AF Rieker, T Hubbard, P Majewski, J Smith, G Moody, N TI Neutron reflectivity investigation of the effects of harsh environments on Ta2N thin films SO THIN SOLID FILMS LA English DT Article DE neutron scattering; tantalum ID TANTALUM NITRIDE FILMS; FRACTURE AB We use neutron reflectivity to study the effects of harsh environments on the composition and structure of Ta2N films. We investigated samples with a 700 Angstrom Ta2N layer, annealed in vacuum, hydrogen, and air, in an attempt to simulate the effects of aging on Ta2N thin films. We obtained good model/data fits for all samples studied, with the exception of the air annealed sample - inhomogeneities and cracking reduced the quality of this fit. A 90 Angstrom thick layer of TaHx was found on top of the hydrogen annealed sample, with no evidence of hydrogen enrichment at the Ta2N/SiO2 interface. Furthermore, we found that air annealing produces a similar to 2000 Angstrom thick layer of tantalum oxide. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ New Mexico, Dept Chem & Nucl Engn, Ctr Microengn Mat, Albuquerque, NM 87131 USA. Univ Calif Los Alamos Natl Lab, Manuel Lujan Jr Neutron Scattering Ctr, Los Alamos, NM 87545 USA. Sandia Natl Labs, Livermore, CA 94551 USA. RP Rieker, T (reprint author), Univ New Mexico, Dept Chem & Nucl Engn, Ctr Microengn Mat, Albuquerque, NM 87131 USA. RI Lujan Center, LANL/G-4896-2012 NR 14 TC 0 Z9 0 U1 0 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD JUN 1 PY 1999 VL 346 IS 1-2 BP 116 EP 119 DI 10.1016/S0040-6090(98)01480-1 PG 4 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 208YE UT WOS:000081019400010 ER PT J AU Bois, FY Smith, TJ Gelman, A Chang, HY Smith, AE AF Bois, FY Smith, TJ Gelman, A Chang, HY Smith, AE TI Optimal design for a study of butadiene toxicokinetics in humans SO TOXICOLOGICAL SCIENCES LA English DT Article DE butadiene population toxicokinetics; human inhalation experiments; Markov chain Monte Carlo simulations; optimal experimental design ID POPULATION TOXICOKINETICS; BAYESIAN-ANALYSIS; GIBBS SAMPLER; IN-VITRO; MODELS; 1,3-BUTADIENE; PHARMACOKINETICS; COMPUTATION; METABOLISM; RATS AB The derivation of the optimal design for an upcoming toxicokinetic study of butadiene in humans is presented. The specific goal of the planned study is to obtain a precise estimate of butadiene metabolic clearance for each study subject, together with a good characterization of its population variance. We used a two-compartment toxicokinetic model, imbedded in a hierarchical population model of variability, in conjunction with a preliminary set of butadiene kinetic data in humans, as a basis for design optimization. Optimization was performed using Monte Carlo simulations. Candidate designs differed in the number and timing of exhaled air samples to be collected. Simulations indicated that only 10 air samples should be necessary to obtain a coefficient of variation of 15% for the estimated clearance rate, if the timing of those samples is properly chosen. Optimal sampling times were found to closely bracket the end of exposure. This efficient design will allow the recruitment of more subjects in the study, in particular to match prescribed levels of accuracy in the estimate of the population variance of the butadiene metabolic rate constant, The techniques presented here have general applicability to the design of human and animal toxicology studies. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Harvard Univ, Sch Publ Hlth, Boston, MA 02115 USA. Columbia Univ, Dept Stat, New York, NY USA. RP Bois, FY (reprint author), Fac Med St Antoine, INSERM, U444 B3E, 27 Rue Chaligny, F-75012 Paris, France. RI Bois, Frederic/E-9241-2012 OI Bois, Frederic/0000-0002-4154-0391 FU NIEHS NIH HHS [ES07581, ES000002, ES07586] NR 50 TC 30 Z9 30 U1 0 U2 6 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 1096-6080 J9 TOXICOL SCI JI Toxicol. Sci. PD JUN PY 1999 VL 49 IS 2 BP 213 EP 224 DI 10.1093/toxsci/49.2.213 PG 12 WC Toxicology SC Toxicology GA 251PY UT WOS:000083455100008 PM 10416266 ER PT J AU Nellist, PD Pennycook, SJ AF Nellist, PD Pennycook, SJ TI Incoherent imaging using dynamically scattered coherent electrons SO ULTRAMICROSCOPY LA English DT Article; Proceedings Paper CT International Workshop Towards Atomic Resolution Analysis (TARA) CY SEP 06-11, 1998 CL PORT LUDLOW, WASHINGTON SP Gatan, Hitachi, JEOL, LEO, Philips, FEI DE scanning transmission electron microscopy (STEM); electron diffraction and elastic scattering theory; image simulation ID ATOMIC-STRUCTURE; GRAIN-BOUNDARY; ADF STEM; RESOLUTION; CRYSTALS; IMAGES; MICROSCOPY; CONTRAST AB We use a Bloch wave approach to show that, even for coherent dynamical scattering from a stationary lattice with no absorption, annular dark-field imaging in a scanning transmission electron microscope gives a direct incoherent structure image of the atomic-column positions of a zone-axis-aligned crystal. Although many Bloch waves may be excited by the probe, the detector provides a filtering effect so that the 1s-type bound states are found to dominate the image contrast for typical experimental conditions. We also find that the column intensity is related to the transverse kinetic energy of the 1s states, which gives atomic number, Z, contrast, The additional effects of phonon scattering are discussed, in particular the reasons why phonon scattering is not a prerequisite for transverse incoherence. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Birmingham, Sch Phys & Astron, Nanoscale Phys Res Lab, Birmingham B17 8DJ, W Midlands, England. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Nellist, PD (reprint author), Univ Birmingham, Sch Phys & Astron, Nanoscale Phys Res Lab, Birmingham B17 8DJ, W Midlands, England. NR 26 TC 266 Z9 267 U1 3 U2 58 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3991 J9 ULTRAMICROSCOPY JI Ultramicroscopy PD JUN PY 1999 VL 78 IS 1-4 BP 111 EP 124 DI 10.1016/S0304-3991(99)00017-0 PG 14 WC Microscopy SC Microscopy GA 206PC UT WOS:000080887400012 ER PT J AU Rafferty, B Pennycook, SJ AF Rafferty, B Pennycook, SJ TI Towards atomic column-by-column spectroscopy SO ULTRAMICROSCOPY LA English DT Article; Proceedings Paper CT International Workshop Towards Atomic Resolution Analysis (TARA) CY SEP 06-11, 1998 CL PORT LUDLOW, WASHINGTON SP Gatan, Hitachi, JEOL, LEO, Philips, FEI ID INELASTIC ELECTRON-DIFFRACTION; SCATTERED ELECTRONS; CRYSTALS AB The optical arrangement of the scanning transmission electron microscope (STEM) is ideally suited for performing analysis of individual atomic columns in materials. Using the incoherent Z-contrast image as a reference, and arranging incoherent conditions also for the spectroscopy, a precise correspondence is ensured between features in the inelastic image and elastic signals. In this way the exact probe position needed to maximise the inelastic signal from a selected column can be located and monitored during the analysis using the much higher intensity elastic signal. Although object functions for EELS are typically less than 1 Angstrom full-width at half-maximum, this is still an order of magnitude larger than the corresponding object functions for elastic (or diffuse) scattering used to form the Z-contrast image. Therefore, the analysis is performed with an effective probe that is significantly broader than that used for the reference Z-contrast image. For a 2.2 Angstrom probe the effective probe is of the order of 2.5 Angstrom, while for a 1.3 Angstrom probe the effective probe is 1.6 Angstrom. Such increases in effective probe size can significantly reduce or even eliminate contrast between atomic columns that are visible in the image. However, this is only true if we consider circular collector apertures. Calculations based upon the theory of Maslen and Rossouw [Maslen and Rossouw, Philos. Mag. 49 (6) (1984) 735-742; Rossouw and Maslen, Philos. Mag. 49 (6) (1984) 743-757] show that employing an annular collector aperture can reduce the FWHM of the inelastic object function down to values close 0.1 Angstrom. With practical collector aperture sizes it should be possible to achieve this increased spatial resolution without losing too much signal. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Rafferty, B (reprint author), Univ Cambridge, Cavendish Lab, Madingley Rd, Cambridge CB3 0HE, England. NR 15 TC 48 Z9 48 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3991 J9 ULTRAMICROSCOPY JI Ultramicroscopy PD JUN PY 1999 VL 78 IS 1-4 BP 141 EP 151 DI 10.1016/S0304-3991(99)00033-9 PG 11 WC Microscopy SC Microscopy GA 206PC UT WOS:000080887400014 ER PT J AU Luo, GM Kaufman, JJ Chiabrera, A Bianco, B Kinney, JH Haupt, D Ryaby, JT Siffert, RS AF Luo, GM Kaufman, JJ Chiabrera, A Bianco, B Kinney, JH Haupt, D Ryaby, JT Siffert, RS TI Computational methods for ultrasonic bone assessment SO ULTRASOUND IN MEDICINE AND BIOLOGY LA English DT Article DE computational methods; ultrasound simulation; trabecular bone; bone mineral density; architecture; fabric; ultrasound velocity; mean frequency; anisotropy ID BOVINE TRABECULAR BONE; CANCELLOUS BONE; ATTENUATION; VELOCITY; ARCHITECTURE; MORPHOLOGY; STRENGTH AB Ultrasound has been proposed as a means to noninvasively assess bone and, particularly, bone strength and fracture risk. Although there has been some success in this application, there is still much that is unknown regarding the propagation of ultrasound through bone. Because strength and fracture risk are a function of both bone mineral density and architectural structure, this study was carried out to examine how architecture and density interact in ultrasound propagation. Due to the difficulties inherent in obtaining fresh bone specimens and associated architectural and density features, simulation methods were used to explore the interactions of ultrasound with bone. A sample of calcaneal trabecular bone was scanned with micro-CT and subjected to morphological image processing (erosions and dilations) operations to obtain a total of 15 three-dimensional (3-D) data sets. Fifteen two-dimensional (2-D) slices obtained from the 3-D data sets were then analyzed to evaluate their respective architectures and densities. The architecture was characterized through the fabric feature, and the density was represented in terms of the bone volume fraction. Computer simulations of ultrasonic propagation through each of the 15 2-D bone slices were carried out, and the ultrasonic velocity and mean frequency of the received waveforms were evaluated. Results demonstrate that ultrasound propagation is affected by both density and architecture, although there was not a simple linear correlation between the relative degree of structural anisotropy with the ultrasound measurements. This study elucidates further aspects of propagation of ultrasound through bone, and demonstrates as well as the power of computational methods for ultrasound research in general and tissue and bone characterization in particular. (C) 1999 World Federation for Ultrasound in Medicine & Biology. C1 CyberLog Inc, New York, NY 10012 USA. NYU, Med Ctr, Dept Vet Affairs Med Ctr, New York, NY 10016 USA. NYU, Med Ctr, Dept Rehabil Med, New York, NY 10016 USA. Mt Sinai Sch Med, Dept Orthoped, New York, NY USA. Univ Genoa, Dept Biophys & Elect Engn, Genoa, Italy. Univ Calif Lawrence Livermore Natl Lab, Dept Mat Sci, Livermore, CA USA. OrthoLog Corp, Tempe, AZ USA. RP Kaufman, JJ (reprint author), CyberLog Inc, 611 Broadway,Suite 707, New York, NY 10012 USA. NR 30 TC 95 Z9 97 U1 0 U2 3 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0301-5629 J9 ULTRASOUND MED BIOL JI Ultrasound Med. Biol. PD JUN PY 1999 VL 25 IS 5 BP 823 EP 830 DI 10.1016/S0301-5629(99)00026-5 PG 8 WC Acoustics; Radiology, Nuclear Medicine & Medical Imaging SC Acoustics; Radiology, Nuclear Medicine & Medical Imaging GA 205KP UT WOS:000080820100012 PM 10414899 ER PT J AU Moridis, GJ AF Moridis, GJ TI Semianalytical solutions for parameter estimation in diffusion cell experiments SO WATER RESOURCES RESEARCH LA English DT Article ID NUMERICAL INVERSION; LAPLACE TRANSFORMS; ROCK SAMPLES; STRONTIUM; CESIUM AB In this paper, semianalytical solutions to the diffusion problem are developed under the conditions of diffusion cell experiments, which involve finite liquid volumes and temporally variable concentrations in the upstream and downstream reservoirs. These solutions account for diffusion in the pores, surface diffusion, mass transfer between the mobile and immobile water fractions, linear sorption (equilibrium or kinetic), and radioactive decay. Fully analytical solutions for both through-diffusion and reservoir-depletion studies are obtained in the Laplace space, which are subsequently numerically inverted to provide the solution in time. The effects of the various diffusion, sorption, and geometric parameters on the solutions under both equilibrium and kinetic linear sorption are investigated. The semianalytical solutions are coupled with an optimization algorithm for parameter estimation, and diffusion and sorption parameters are determined using experimental data. The semianalytical solutions are shown to have significant advantages over the conventional graphical approach because (1) they are not based on the often invalid assumption of constant upstream and negligible downstream concentrations, (2) they double the amount of data from which to extract the pertinent diffusion and sorption parameters, and (3) they allow differentiation between equilibrium and kinetic sorption. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Moridis, GJ (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, 1 Cyclotron Rd,MS 90-1116, Berkeley, CA 94720 USA. NR 29 TC 17 Z9 17 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD JUN PY 1999 VL 35 IS 6 BP 1729 EP 1740 DI 10.1029/1999WR900084 PG 12 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 198ZC UT WOS:000080453800004 ER PT J AU Weissmann, GS Carle, SF Fogg, GE AF Weissmann, GS Carle, SF Fogg, GE TI Three dimensional hydrofacies modeling based on soil surveys and transition probability geostatistics SO WATER RESOURCES RESEARCH LA English DT Article ID INDICATOR GEOSTATISTICS; AQUIFERS AB Typical hydrogeologic data sets consisting of information from boreholes provide excellent information on vertical variability of sedimentary deposits but very limited information on lateral distribution and variability. In cases where surface geomorphic features reflect processes similar to those responsible for past deposition, the soil survey offers a resource for assessing the lateral sediment variability. Facies mean length and transition probability measurements of C horizon textures from the soil maps on the Kings River alluvial fan, California, provide a basis for Markov chain models of spatial variability in the principal lateral directions and facies orientation information for the horizontal plane. Incorporation with a Markov chain model of vertical-direction transitions based on well data yields a three-dimensional Markov chain model of sediment variability which includes cross correlation between sediment types and representation of asymmetry (e.g., fining upward tendencies). Use of the model in geostatistical conditional simulation and simulated annealing produces a detailed, geologically plausible image of the subsurface hydrofacies distribution. C1 Univ Calif Davis, Davis, CA 95616 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Weissmann, GS (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 34 TC 121 Z9 130 U1 2 U2 26 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD JUN PY 1999 VL 35 IS 6 BP 1761 EP 1770 DI 10.1029/1999WR900048 PG 10 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 198ZC UT WOS:000080453800007 ER PT J AU Hubbard, SS Rubin, Y Majer, E AF Hubbard, SS Rubin, Y Majer, E TI Spatial correlation structure estimation using geophysical and hydrogeological data SO WATER RESOURCES RESEARCH LA English DT Article ID GROUND-PENETRATING-RADAR; CLAY CONTENT; HYDRAULIC CONDUCTIVITY; NUMERICAL-SIMULATION; WATER-MOVEMENT; SEISMIC DATA; PERMEABILITY; TRANSPORT; TOMOGRAPHY; POROSITY AB The large spatial variability of hydraulic properties in natural geologic systems over a wide range of scales, and the difficulty of collecting representative and sufficient hydraulic property measurements using conventional sampling techniques, render estimation of spatial correlation parameters difficult. Further compounding the estimation problem is the observation that the integral scale estimate is a function of the measurement support scale. To mitigate these problems, we investigate the use of tomographic geophysical data in combination with hydrogeological data in the spatial correlation estimation procedure. Two synthetic case studies were investigated where the scale of the geophysical measurements were varied relative to the scale of the hydrogeological properties. The spatial correlation structure parameter estimation procedure was performed in the spectral domain, where analysis of data having different support scales and spatial sampling windows was facilitated. Comparison of the spatial correlation structure parameters estimated from measured data with those of the synthetic aquifers revealed which type of data (tomographic, hydrogeological, or a combination of both) was most effective for recovering spatial correlation statistics under different sampling/heterogeneity conditions. These synthetic case studies suggest that collection of a few tomographic profiles and interpretation of these profiles together with limited well bore data can yield correlation structure information that is otherwise obtainable only from extensive hydrological sampling. C1 Univ Calif Berkeley, Dept Civil & Environm Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Hubbard, SS (reprint author), Univ Calif Berkeley, Dept Civil & Environm Engn, Berkeley, CA 94720 USA. RI Hubbard, Susan/E-9508-2010 NR 64 TC 51 Z9 51 U1 1 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD JUN PY 1999 VL 35 IS 6 BP 1809 EP 1825 DI 10.1029/1999WR900040 PG 17 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 198ZC UT WOS:000080453800012 ER PT J AU Tartakovsky, DM Neuman, SP AF Tartakovsky, DM Neuman, SP TI Extension of "Transient flow in bounded randomly heterogeneous domains, 1, Exact conditional moment equations and recursive approximations" SO WATER RESOURCES RESEARCH LA English DT Article AB In a recent paper we developed exact nonlocal conditional moment equations for transient flow in bounded domains driven by random forcing terms (sources, initial head, and boundary conditions). Whereas our conditional mean equations took into account the randomness of forcing terms, our conditional second moment equations did not. We do so in this brief addendum. C1 Univ Calif Los Alamos Natl Lab, Grp CIC19, Los Alamos, NM 87545 USA. Univ Arizona, Dept Hydrol & Water Resources, Tucson, AZ 85721 USA. RP Tartakovsky, DM (reprint author), Univ Calif Los Alamos Natl Lab, Grp CIC19, MS B256, Los Alamos, NM 87545 USA. RI Tartakovsky, Daniel/E-7694-2013 NR 1 TC 22 Z9 22 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD JUN PY 1999 VL 35 IS 6 BP 1921 EP 1925 DI 10.1029/1999WR900044 PG 5 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 198ZC UT WOS:000080453800021 ER PT J AU Katsarakis, N Chatzitheodoridis, E Kiriakidis, G Sigalas, MM Soukoulis, CM Leung, WY Tuttle, G AF Katsarakis, N Chatzitheodoridis, E Kiriakidis, G Sigalas, MM Soukoulis, CM Leung, WY Tuttle, G TI Laser-machined layer-by-layer metallic photonic band-gap structures SO APPLIED PHYSICS LETTERS LA English DT Article ID CRYSTALS AB Metallic photonic band-gap crystals operating in the microwave frequency range were fabricated by laser precision machining. They consist of stainless steel plates with a tetragonal lattice of holes and a lattice constant of 15 mm. Transmission measurements show that periodic crystals exhibit a cutoff frequency in the 8-18 GHz range, below which no propagation is allowed. The cutoff frequency can be easily tuned by varying the interlayer distance or the filling fraction of the metal. Combinations of plates with different hole diameters create defect modes with relatively sharp peaks, which are tunable. The experimental measurements are in good agreement with theoretical calculations. (C) 1999 American Institute of Physics. [S0003-6951(99)03822-X]. C1 Fdn Res & Technol Hellas, Inst Elect Struct & Laser, Mat Grp, Heraklion 71110, Greece. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Microelect Res Ctr, Ames, IA 50011 USA. RP Katsarakis, N (reprint author), Fdn Res & Technol Hellas, Inst Elect Struct & Laser, Mat Grp, Heraklion 71110, Greece. RI Chatzitheodoridis, Elias/A-1414-2009; Kiriakidis, George/G-9685-2011; Soukoulis, Costas/A-5295-2008 NR 10 TC 10 Z9 10 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 31 PY 1999 VL 74 IS 22 BP 3263 EP 3265 DI 10.1063/1.123314 PG 3 WC Physics, Applied SC Physics GA 199HC UT WOS:000080474300007 ER PT J AU Holloway, BC Kraft, O Shuh, DK Kelly, MA Nix, WD Pianetta, P Hagstrom, S AF Holloway, BC Kraft, O Shuh, DK Kelly, MA Nix, WD Pianetta, P Hagstrom, S TI Interpretation of x-ray photoelectron spectra of elastic amorphous carbon nitride thin films SO APPLIED PHYSICS LETTERS LA English DT Article ID COMPUTER-SIMULATION; DEPOSITION; MICROSTRUCTURE; CNX AB We report the synthesis and characterization of amorphous carbon nitride (CNx) thin films using a direct current magnetron reactive sputter system. Nanoindentation of the CNx films and amorphous carbon films deposited under similar conditions shows the CNx films are extremely elastic, that the addition of nitrogen fundamentally changes the mechanical properties of the films, and that traditional methods of calculating the hardness and Young's modulus may not be valid. X-ray photoelectron spectroscopy (XPS) of the N(1s) and C(1s) core levels show multiple bonding arrangements. In a new interpretation of the XPS data, the two predominant N( 1s) spectral features have been identified, based on comparison to reference data in the literature, as those belonging to nitrogen in a four-bond arrangement and nitrogen in a three-bond arrangement, independent of hybridization. The formation of a fourth bond allows nitrogen to substitute for C atoms in a carbon-based graphitic system without the formation of dangling bonds or unfilled states. The relationship between nitrogen incorporation in a carbon-based ring structure and measured film properties is rationalized based on previously published models. (C) 1999 American Institute of Physics. [S0003-6951(99)00122-9]. C1 Coll William & Mary, Dept Appl Sci, Williamsburg, VA 23187 USA. Max Planck Inst Met Forsch, D-70174 Stuttgart, Germany. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Stanford Univ, Dept Mat Sci & Engn, Stanford, CA 94305 USA. RP Holloway, BC (reprint author), Coll William & Mary, Dept Appl Sci, Williamsburg, VA 23187 USA. NR 14 TC 48 Z9 50 U1 0 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 31 PY 1999 VL 74 IS 22 BP 3290 EP 3292 DI 10.1063/1.123362 PG 3 WC Physics, Applied SC Physics GA 199HC UT WOS:000080474300016 ER PT J AU Kim, D Shen, YR AF Kim, D Shen, YR TI Study of wet treatment of polyimide by sum-frequency vibrational spectroscopy SO APPLIED PHYSICS LETTERS LA English DT Article ID SURFACE MODIFICATION; LIQUID-CRYSTALS; ADHESION; GENERATION; POLYMER; FILMS AB A polyimide surface treated with a strong NaOH solution for improvement of adhesion with metals was investigated using ultraviolet absorption and sum-frequency vibrational spectroscopy. Conversion of imide groups to amide groups at the polyimide surface was observed. This conversion and subsequent etching of the polyimide film by the solution seems to be more effective in the amorphous part of the film. Drying of the film converts the surface amides back to imides. (C) 1999 American Institute of Physics. [S0003-6951(99)05022-6]. C1 Sogang Univ, Dept Phys, Seoul 100611, South Korea. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Kim, D (reprint author), Sogang Univ, Dept Phys, Seoul 100611, South Korea. RI Kim, Doseok/J-8776-2013 NR 16 TC 44 Z9 44 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 31 PY 1999 VL 74 IS 22 BP 3314 EP 3316 DI 10.1063/1.123329 PG 3 WC Physics, Applied SC Physics GA 199HC UT WOS:000080474300024 ER PT J AU Stephenson, GB Eastman, JA Thompson, C Auciello, O Thompson, LJ Munkholm, A Fini, P DenBaars, SP Speck, JS AF Stephenson, GB Eastman, JA Thompson, C Auciello, O Thompson, LJ Munkholm, A Fini, P DenBaars, SP Speck, JS TI Observation of growth modes during metal-organic chemical vapor deposition of GaN SO APPLIED PHYSICS LETTERS LA English DT Article ID MOLECULAR-BEAM EPITAXY; ENERGY ELECTRON-DIFFRACTION; X-RAY-SCATTERING; HIGH-QUALITY GAN; GALLIUM NITRIDE; FILM GROWTH; PHASE; OSCILLATIONS; NUCLEATION; AMMONIA AB We present real-time surface x-ray scattering measurements during homoepitaxial growth of GaN by metal-organic chemical vapor deposition. We observed intensity oscillations corresponding to the completion of each monolayer during layer-by-layer growth. The growth rate was found to be temperature independent and Ga-transport limited. Transitions between step-flow, layer-by-layer, and three-dimensional growth modes were determined as a function of temperature and growth rate. (C) 1999 American Institute of Physics. [S0003-6951(99)01622-8]. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Univ Calif Santa Barbara, Dept Mat, Santa Barbara, CA 93106 USA. RP Stephenson, GB (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Eastman, Jeffrey/E-4380-2011; Speck, James/H-5646-2011; OI Eastman, Jeff/0000-0002-0847-4265; Thompson, Carol/0000-0003-3832-4855 NR 29 TC 44 Z9 45 U1 1 U2 15 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 31 PY 1999 VL 74 IS 22 BP 3326 EP 3328 DI 10.1063/1.123333 PG 3 WC Physics, Applied SC Physics GA 199HC UT WOS:000080474300028 ER PT J AU Lee, SR Wright, AF Crawford, MH Petersen, GA Han, J Biefeld, RM AF Lee, SR Wright, AF Crawford, MH Petersen, GA Han, J Biefeld, RM TI The band-gap bowing of AlxGa1-xN alloys SO APPLIED PHYSICS LETTERS LA English DT Article ID CHEMICAL-VAPOR-DEPOSITION; OPTICAL-PROPERTIES; SPECTROSCOPIC ELLIPSOMETRY; STRAINED ALGAN; FILMS; PHOTOLUMINESCENCE; SAPPHIRE; GROWTH; LAYERS; EDGE AB The band gap of AlxGa1-xN is measured for the composition range 0 less than or equal to x<0.45; the resulting bowing parameter, b=+0.69 eV, is compared to 20 previous works. A correlation is found between the measured band gaps and the methods used for epitaxial growth of the AlxGa1-xN:directly nucleated or buffered growths of AlxGa1-xN initiated on sapphire at temperatures T>800 degrees C usually lead to stronger apparent bowing (b>+1.3 eV); while growths initiated using low-temperature buffers on sapphire, followed by high-temperature growth, lead to weaker bowing (b<+1.3 eV). Extant data suggest that the intrinsic band-gap bowing parameter for AlGaN alloys is b=+0.62(+/-0.45) eV. (C) 1999 American Institute of Physics. [S0003-6951(99)02822-3]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Lee, SR (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 37 TC 139 Z9 145 U1 2 U2 20 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 31 PY 1999 VL 74 IS 22 BP 3344 EP 3346 DI 10.1063/1.123339 PG 3 WC Physics, Applied SC Physics GA 199HC UT WOS:000080474300034 ER PT J AU Miskowski, VM Franzen, S Shreve, AP Ondrias, MR Wallace-Williams, SE Barr, ME Woodruff, WH AF Miskowski, VM Franzen, S Shreve, AP Ondrias, MR Wallace-Williams, SE Barr, ME Woodruff, WH TI Distortional isomers of a mixed-valence binuclear Cu complex SO INORGANIC CHEMISTRY LA English DT Article ID INTRAMOLECULAR ELECTRON-TRANSFER; RAMAN-SPECTROSCOPY; OXIDASE; SITE; FORMS; BOND AB The resonance Raman spectra of a mixed-valence copper dimer [Cu-2(L)](3+) encapsulated by the ligand L = N(CH2CH2N(H)CH2CH2N(H)CH2CH2)(3)N are reported. Copper isotope data (Cu-63/65) of solution spectra of [Cu-2(L)](3+) allow identification of vibrational bands at 289 and 172 cm(-1) as predominately Cu-Cu stretching and Cu-Cu-N-eq bending modes. The results indicate that the Cu-Cu bond is sufficiently weak that ligand conformations, influenced by hydrogen bonding, can give rise to distortional isomers of the Cu-Cu bond. C1 N Carolina State Univ, Dept Chem, Raleigh, NC 27695 USA. Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div CST 4, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Nucl Mat & Technol Div NMT 6, Los Alamos, NM 87545 USA. Univ New Mexico, Dept Chem, Albuquerque, NM 87131 USA. RP Woodruff, WH (reprint author), N Carolina State Univ, Dept Chem, Box 8204, Raleigh, NC 27695 USA. NR 21 TC 16 Z9 16 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD MAY 31 PY 1999 VL 38 IS 11 BP 2546 EP 2547 DI 10.1021/ic981415c PG 2 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 203HF UT WOS:000080701900001 ER PT J AU Vollhardt, KPC Cammack, JK Matzger, AJ Bauer, A Capps, KB Hoff, CD AF Vollhardt, KPC Cammack, JK Matzger, AJ Bauer, A Capps, KB Hoff, CD TI Thermodynamic and kinetic study of oxidative addition reductive elimination of H-2 and D-2 to fulvaleneCr(2)(CO)(6): Evidence for relatively strong metal-metal bonds in fulvalenedimetals SO INORGANIC CHEMISTRY LA English DT Article ID MOLECULAR-HYDROGEN; CARBONYL-COMPLEXES; CHEMISTRY; MO; SUBSTITUTION; MOLYBDENUM; DIHYDROGEN; EFFICIENT; HYDRIDES; BINDING AB Hydrogen adds reversibly to the chromium-chromium bond of FvCr(2)(CO)(6) yielding FVCr2(CO)(6)(H)(2) (Fv = fulvalene). Equilibrium data for this process have been measured in toluene and deuteriobenzene in the temperature range 50-80 degrees C and pressures up to 72 atm H-2 [Delta H degrees = - 1.0(0.4) kcal/mol, Delta S degrees = - 14.0(2.0) cal/mol deg]. These data are used to estimate the enthalpy [16.5 (2.0) kcal/mol] and entropy (11 cal/mol deg) for breaking the Cr-Cr bond in FvCr(2)(CO)(6). A theoretical calculation of the isodesmic process FVCr2(CO)(6)(H)(2) + [eta(5)-C5H5Cr(CO)(3)](2) --> FvCr(2)(CO)(6) + 2 eta(5)-C5H5Cr(CO)(3)H predicts it to have an enthalpy of -1.74 kcal/mol, very close to the experimental value of -2 kcal/mol. Thus, and assuming that the individual Cr-H bonds in FVCr2(CO)(6)(H)(2) and eta(5)-C5H5Cr(CO)(3)H are equal, these results lead to the conclusion that the metal-metal bond in the fulvalene system is 2 +/- 2 kcal/mol stronger than that in [eta(5)-C5H5Cr(CO)(3)](2), despite the greater Cr-Cr bond length in the former. This result is also in accord with the measured enthalpy of reaction [FvCr(2)(CO)(6)](2-)(Na+)(2) + [eta(5)-C5H5Cr(CO)(3)](2) --> FvCr(2)(CO)(6) + 2 [eta(5)-C5H5Cr(CO)(3)]Na--(+), Delta H = - 2.4(0.4) kcal/mol. Deuterium was found to add to FvCr(2)(CO)(6) with a normal equilibrium isotope effect: K-eq(H-2)/K-eq(D-2) 1.45(0.10). A kinetic study of reductive elimination of H-2 in the temperature range 45-75 degrees C shows that it obeys first-order kinetics: [k(-1)(45.5) = 1.0 x 10(-5) s(-1), Delta H-double dagger = 27.8(2.0) kcal/mol, Delta S-double dagger = 5.6(3.0) cal/mol deg]. Similarly, the oxidative addition reaction reveals first-order behavior in both FvCr(2)(CO)(6) and H-2 [Delta H-double dagger = 26.8(2.5) kcal/mol, Delta S-double dagger = -19.6 (6.0) cal/mol deg]. The obtained combined kinetic data are in reasonable agreement with the measured equilibrium constant. The rate of hydrogenation under 60 atm of H-2 is not retarded by addition of 15 atm of CO, arguing against a transition state involving CO loss. Studies of the rate of oxidative addition/reductive elimination of D-2 suggest a late transition state for the former which involves cleavage of the D-D (H-H) bond. Substitution of (CO.)-C-12 in FvCr(2)((CO)-C-12)(6) by (CO)-C-13 occurs 1-2 orders of magnitude faster than does hydrogenation [k(1)(43.7) = 5.6 x 10(-6) s(-1) atm(-1), Delta H-double dagger = 16.7(1.5) kcal/mol, Delta S-double dagger = - 30.0(4.0) cal/mol deg] but is much slower than in analogous complexes [eta(5)-C5R5Cr(CO)(3)](2) (R = H, Me). The crystal structure of [FVCr2(CO)(6)](2)-(Na+)(2) is reported. C1 Univ Calif Berkeley, Dept Chem, Div Chem Sci, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Miami, Dept Chem, Coral Gables, FL 33124 USA. RP Vollhardt, KPC (reprint author), Univ Calif Berkeley, Dept Chem, Div Chem Sci, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RI Matzger, Adam/G-7497-2016 OI Matzger, Adam/0000-0002-4926-2752 NR 69 TC 17 Z9 17 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD MAY 31 PY 1999 VL 38 IS 11 BP 2624 EP 2631 DI 10.1021/ic981360e PG 8 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 203HF UT WOS:000080701900014 ER PT J AU Baker, GA AF Baker, GA TI Algebraic approximants and the numerical solution of parabolic equations SO JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS LA English DT Article DE hermite-Pade approximant; algebraic approximant; Pade approximant; partial differential equation; heat equation; parabolic equation AB The heat equation is but one example of problems which involve multiple scales. There is a lot of transient behavior which for many problems is of no particular interest. What is of concern is the long time-scale behavior. However the presence of the short time-scale behavior would seem to require numerical integration methods to take very short time steps to follow the behavior accurately. For these problems, what is desired is a numerical method which is accurate for the long time-scale behavior, and causes the transients to die out quickly. That their rate of decay is not quite right is not important for this class of problems. A formalism is developed which allows the straightforward derivation of finite-difference schemes which involve several prior times from algebraic approximants. The algebraic approximants turn out to be, in a quite natural way, approximations to the function exp{-4 mu[arcsin(root w/4)](2)} where mu = kappa Delta t/(Delta x)(2) is the Courant number. Several of the simpler cases are investigated, and, of the implicit schemes, a couple are found to be, not only of higher order accuracy than most currently popular schemes, but also unconditionally stable and in fact unconditionally stiff stable! The higher order accuracy and stiff stability properties are just what is required for this sort of problem. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 6 TC 0 Z9 0 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0427 J9 J COMPUT APPL MATH JI J. Comput. Appl. Math. PD MAY 31 PY 1999 VL 105 IS 1-2 BP 129 EP 139 DI 10.1016/S0377-0427(99)00042-4 PG 11 WC Mathematics, Applied SC Mathematics GA 202ZD UT WOS:000080681500009 ER PT J AU Choo, H Bourke, M Nash, P Daymond, M Shi, N AF Choo, H Bourke, M Nash, P Daymond, M Shi, N TI Thermal residual stresses in NiAl-AlN-Al2O3 composites measured by neutron diffraction SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE residual stress; neutron diffraction; NiAl; composite ID MECHANICAL-PROPERTIES; MATRIX AB Thermal residual stresses in NiAl-(AlN)(Particle)-(Al2O3)(Fiber) composites were measured at room temperature for two Al2O3 fiber volume fractions (5 and 30%) using neutron powder diffraction. Lattice parameters in each phase were obtained by refining diffraction patterns using Rietveld analysis and lattice strains were calculated from changes in their values. By assuming a volume averaged hydrostatic situation, in conjunction with an FE model that was used to infer the initial stresses between NiAl and AlN, the strains were converted into stresses. The tensile residual stresses in the NiAl matrix were 0.2 and 0.6 GPa for the 5 and 30% Al2O3 composites respectively. The compressive residual stress in the AlN dispersion particles decreased from -1.5 to -1.1 GPa as the fiber volume fraction increased from 5 to 30%. The compressive residual stresses in the Al2O3 fibers were -1.7 and -1.3 GPa for the 5 and 30% Al2O3 composites respectively. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Los Alamos Natl Lab, Manuel Lujan Jr Neutron Scattering Ctr, Los Alamos, NM 87545 USA. IIT, Chicago, IL 60616 USA. RP Choo, H (reprint author), Los Alamos Natl Lab, Manuel Lujan Jr Neutron Scattering Ctr, POB 1663, Los Alamos, NM 87545 USA. EM choo@lanl.gov RI Choo, Hahn/A-5494-2009; OI Choo, Hahn/0000-0002-8006-8907; Nash, Philip/0000-0003-2975-8512; Daymond, Mark/0000-0001-6242-7489 NR 32 TC 18 Z9 18 U1 0 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD MAY 31 PY 1999 VL 264 IS 1-2 BP 108 EP 121 DI 10.1016/S0921-5093(98)01116-2 PG 14 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 188RW UT WOS:000079863100010 ER PT J AU Hong, SI Hill, MA AF Hong, SI Hill, MA TI Mechanical stability and electrical conductivity of Cu-Ag filamentary microcomposites SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE filament; interface; dislocation; strength; conductivity; microstructure; electron scattering; resistivity ID COPPER COMPOSITE WIRES; NB COMPOSITES; HIGH-STRENGTH; SINGLE-CRYSTALS; MICROSTRUCTURE; ALLOYS; DRAWN; RESISTIVITY; BEHAVIOR; SLIP AB One of the most important features in two-phase Cu-Ag filamentary microcomposites is the abundance of interfaces compared with conventional copper-based alloys. In heavily drawn Cu-Ag filamentary microcomposites, the microstructure is extremely fine and the interphase area is too large to maintain a stable internal dislocation structure because of closely spaced filaments. Rather, most dislocations are thought to be absorbed at the interfaces as the draw ratio increases. The mechanical and electrical properties of Cu-Ag filamentary microcomposite wires were examined and correlated with the microstructural changes caused by thermomechanical treatments. The study of the electrical conductivity combined with the microstructural analyses indicates that the resistivity of Cu-Ag microcomposites is predominantly controlled by electron scattering at Cu-Ag interfaces. The substantial increase in electrical conductivity at high annealing temperatures is mainly due to dissolution and coarsening of silver filaments. The relatively low ratio of the resistivities at 293 and 77 K (rho(293 K)/rho(77 K)) can also be explained by the contribution of interface scattering. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Chungnam Natl Univ, Dept Met Engn, Taedok Sci Town 305764, Taejon, South Korea. Los Alamos Natl Lab, Div Mat Sci, Los Alamos, NM 87545 USA. RP Chungnam Natl Univ, Dept Met Engn, Taedok Sci Town 305764, Taejon, South Korea. NR 34 TC 81 Z9 115 U1 2 U2 12 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 EI 1873-4936 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD MAY 31 PY 1999 VL 264 IS 1-2 BP 151 EP 158 DI 10.1016/S0921-5093(98)01097-1 PG 8 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 188RW UT WOS:000079863100014 ER PT J AU Peralta, P Laird, C Mitchell, TE AF Peralta, P Laird, C Mitchell, TE TI Fatigue fracture at copper bicrystal interfaces: fractography SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE copper bicrystal interface; fatigue fracture; fractography; slip geometry ID CYCLIC DEFORMATION; CRACK-GROWTH; DEPENDENCE; CRYSTAL AB The fracture surfaces of intergranular cracks in copper bicrystals with different misorientations, subjected to different mechanical pretreatments and cracking directions, were studied by scanning electron microscopy (SEM). The dislocation structures present before the crack formed and propagated were characterized by transmission electron microscopy (TEM). It was found that they could be either loop patches and persistent slip bands (PSB's) (single slip) or maze and cell structures (multiple slip) depending on the misorientation and the pretreatment. The results showed that these structures influenced the shape of the crack front, which could be aligned close to specific crystallographic directions or straight depending on the prior structure. The crack propagation direction also influenced the morphology of the crack front, macroscopically and microscopically, due to differences in the multiplicity of slip. These results suggest that, for a ductile metal, the fatigue cracking behavior depends mostly on hardening and overall dislocation structure, even when the crack is propagating intergranularly. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. Univ Penn, Dept Mat Sci & Engn, Philadelphia, PA 19104 USA. RP Peralta, P (reprint author), Arizona State Univ, Dept Mech & Aerosp Engn, Tempe, AZ 85287 USA. NR 22 TC 2 Z9 2 U1 0 U2 7 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD MAY 31 PY 1999 VL 264 IS 1-2 BP 215 EP 231 DI 10.1016/S0921-5093(98)01088-0 PG 17 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 188RW UT WOS:000079863100023 ER PT J AU Brace, D Morariu, B Zumino, B AF Brace, D Morariu, B Zumino, B TI T-duality and Ramond-Ramond backgrounds in the Matrix model SO NUCLEAR PHYSICS B LA English DT Article DE matrix model; non-commutative super Yang-Mills; T-duality ID C-STAR-ALGEBRAS; PROJECTIVE-MODULES; U-DUALITY; SPACES AB We investigate T-duality of toroidally compactified Matrix model with arbitrary Ramond-Ramond backgrounds in the framework of non-commutative super Yang-Mills gauge theory. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. EM brace@thwk2.lbl.gov; morariu@thsrv.lbl.gov; zumino@thsrv.lbl.gov NR 58 TC 32 Z9 32 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 EI 1873-1562 J9 NUCL PHYS B JI Nucl. Phys. B PD MAY 31 PY 1999 VL 549 IS 1-2 BP 181 EP 193 DI 10.1016/S0550-3213(99)00168-6 PG 13 WC Physics, Particles & Fields SC Physics GA 206QD UT WOS:000080889800006 ER PT J AU Lapikas, L Wesseling, J Wiringa, RB AF Lapikas, L Wesseling, J Wiringa, RB TI Nuclear structure studies with the Li-7(e, e(l)p) reaction SO PHYSICAL REVIEW LETTERS LA English DT Article ID MONTE-CARLO CALCULATIONS; SINGLE-PARTICLE PROPERTIES; KNOCK-OUT; SPECTROSCOPIC FACTORS; ELECTRON-SCATTERING; MOMENTA; MATTER; O-16; LI-6 AB Experimental momentum distributions for the transitions to the ground stare and first excited state of He-6 have been measured via the reaction Li-7(e, e'p)He-6. They are compared to theoretical distributions calculated with variational Monte Carlo (VMC) wave functions which include strong state-dependent correlations in both Li-7 and He-6. These VMC calculations provide a parameter-free prediction that reproduces the measured data, including its normalization. The deduced spectroscopic factor for the two transitions is 0.58 +/- 0.05, in perfect agreement with the VMC value of 0.60. This is the first successful comparison of experiment and nb initio theory for spectroscopic factors in p-shell nuclei. [S0031-9007(99)09267-4]. C1 NIKHEF H, NL-1009 DB Amsterdam, Netherlands. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. RP Lapikas, L (reprint author), NIKHEF H, POB 41882, NL-1009 DB Amsterdam, Netherlands. RI Wiringa, Robert/M-4970-2015 NR 35 TC 49 Z9 50 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 31 PY 1999 VL 82 IS 22 BP 4404 EP 4407 DI 10.1103/PhysRevLett.82.4404 PG 4 WC Physics, Multidisciplinary SC Physics GA 200NQ UT WOS:000080546900009 ER PT J AU Hamilton, JC Stumpf, R Bromann, K Giovannini, M Kern, K Brune, H AF Hamilton, JC Stumpf, R Bromann, K Giovannini, M Kern, K Brune, H TI Dislocation structures of submonolayer films near the commensurate-incommensurate phase transition: Ag on Pt(111) SO PHYSICAL REVIEW LETTERS LA English DT Article ID TOTAL-ENERGY CALCULATIONS; WAVE BASIS-SET; MOLECULAR-DYNAMICS; RECONSTRUCTION; SURFACE; AU(111); METALS AB Submonolayer films of AE on Pt(111) exhibit parallel partial dislocations separated by narrow hcp domains and much wider fcc domains, the large difference in width being atypical of strained metal overlayers on close-packed substrates. Using a two-dimensional Frenkel-Kontorova model, we calculate the relative domain widths. We examine possible effects of dislocations on equilibrium island shape and calculate the energies of stable and metastable dislocation structures versus island size. Experimental results are explained by proximity to the incommensurate-commensurate phase transition. [S0031-9007(99)09291-1]. C1 Sandia Natl Labs, Livermore, CA 94551 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Ecole Polytech Fed Lausanne, Inst Phys Expt, CH-1015 Lausanne, Switzerland. RP Hamilton, JC (reprint author), Sandia Natl Labs, Livermore, CA 94551 USA. RI Brune, Harald/E-7284-2017 OI Brune, Harald/0000-0003-4459-3111 NR 16 TC 24 Z9 24 U1 0 U2 12 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 31 PY 1999 VL 82 IS 22 BP 4488 EP 4491 DI 10.1103/PhysRevLett.82.4488 PG 4 WC Physics, Multidisciplinary SC Physics GA 200NQ UT WOS:000080546900030 ER PT J AU Niklasson, AMN Johansson, B Nordstrom, L AF Niklasson, AMN Johansson, B Nordstrom, L TI Spin density waves in thin chromium films SO PHYSICAL REVIEW LETTERS LA English DT Article ID CALCULATED OSCILLATION PERIODS; FE/CR(001) SUPERLATTICES; CR; MAGNETISM; LAYERS; ANTIFERROMAGNETISM; MULTILAYERS; SANDWICHES AB The magnetic profile of Fe/Cr-N/Fe bcc(001) films has been calculated by means of first principles density functional theory. It is shown that the magnetic profile of the chromium spacer can be expressed in terms of spin density waves (SDW). The dispersion and amplitude of the SDW are determined and the effects from the finite film thickness are observed and discussed. It is found that the SDW wave vectors are quantized and that for certain Cr thicknesses two SDWs with different wavelengths coexist. Connections to the magnetic interlayer coupling are discussed. [S0031-9007(99)09241-8]. C1 Uppsala Univ, Dept Phys, Condensed Matter Theory Grp, S-75121 Uppsala, Sweden. RP Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 27 TC 43 Z9 44 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 31 PY 1999 VL 82 IS 22 BP 4544 EP 4547 DI 10.1103/PhysRevLett.82.4544 PG 4 WC Physics, Multidisciplinary SC Physics GA 200NQ UT WOS:000080546900044 ER PT J AU Cho, JH Zhang, SB AF Cho, JH Zhang, SB TI Comment on "identification of the Si 2p surface core level shifts on the Sb/Si(001)-(2 x 1) interface" SO PHYSICAL REVIEW LETTERS LA English DT Article ID SI(001); FILMS; GE C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Cho, JH (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Krausnick, Jennifer/D-6291-2013; Zhang, Shengbai/D-4885-2013; Cho, Jun-Hyung/R-7256-2016 OI Zhang, Shengbai/0000-0003-0833-5860; Cho, Jun-Hyung/0000-0002-1785-1835 NR 9 TC 3 Z9 3 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 31 PY 1999 VL 82 IS 22 BP 4564 EP 4564 DI 10.1103/PhysRevLett.82.4564 PG 1 WC Physics, Multidisciplinary SC Physics GA 200NQ UT WOS:000080546900049 ER PT J AU Supek, S Aine, CJ Ranken, D Best, E Flynn, ER Wood, CC AF Supek, S Aine, CJ Ranken, D Best, E Flynn, ER Wood, CC TI Single vs. paired visual stimulation: superposition of early neuromagnetic responses and retinotopy in extrastriate cortex in humans SO BRAIN RESEARCH LA English DT Article DE transient evoked field; human visual cortex; extrastriate area; neuromagnetic source localization; retinotopy; superposition of response; paired stimuli ID POSITRON EMISSION TOMOGRAPHY; SELECTIVE ATTENTION; MODEL; ORGANIZATION; LOCALIZATION; PARAMETERS; RESOLUTION; LOCATIONS; STREAMS; AREAS AB Neuromagnetic techniques were used in conjunction with magnetic resonance imaging (MRI) techniques to: (1) localize and characterize cortical sources evoked by visual stimuli presented at different locations in the lower right visual field; (2) examine the superposition of cortical responses by comparing the summation of responses to the presentation of single stimuli with responses to paired stimuli; and (3) examine the spatial resolution of magnetoencephalographic (MEG) techniques by comparing the identified source locations evoked by the presentation of single vs. paired stimuli. Using multi-dipole, non-linear minimization analyses, three sources were localized for each stimulus condition during the initial 80-170 ms poststimulus interval for all subjects. In addition to an occipital source, two extrastriate sources were identified: occipital-parietal and occipital-temporal. Each source evidenced a systematic shift in location associated with changes in stimulus placement parallel to the vertical meridian. To our knowledge, this is the first demonstration of retinotopic organization of extrastriate areas, using non-invasive neuromagnetic techniques. The paired presentation of stimuli reflected superposition of the responses evoked by single stimuli but only for early activity up to 150 ms poststimulus. Undersummation was evident after 150 ms. All sources identified for single stimuli were also identified in the paired-stimulus responses; but at the expense of larger errors for some of the estimated parameters. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Vet Adm Med Ctr, Ctr Funct Brain Imaging, Albuquerque, NM 87108 USA. Univ Zagreb, Fac Sci, Dept Phys, HR-10002 Zagreb, Croatia. Univ Zagreb, Croatian Inst Brain Res, Salata 3B, HR-10002 Zagreb, Croatia. Univ New Mexico, Sch Med, Dept Radiol, Albuquerque, NM 87131 USA. Los Alamos Natl Lab, Biophys Grp, Los Alamos, NM 87545 USA. Natl Fdn Funct Brain Imaging, Albuquerque, NM 87106 USA. RP Aine, CJ (reprint author), Vet Adm Med Ctr, Ctr Funct Brain Imaging, 1501 San Pedro Dr SE,Bldg 49,114M, Albuquerque, NM 87108 USA. EM aine@lanl.gov FU NEI NIH HHS [EY08610] NR 49 TC 28 Z9 29 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0006-8993 J9 BRAIN RES JI Brain Res. PD MAY 29 PY 1999 VL 830 IS 1 BP 43 EP 55 DI 10.1016/S0006-8993(99)01316-5 PG 13 WC Neurosciences SC Neurosciences & Neurology GA 201WY UT WOS:000080620900007 PM 10350559 ER PT J AU Zhu, JH Pike, LM Liu, CT Liaw, PK AF Zhu, JH Pike, LM Liu, CT Liaw, PK TI Point defects in binary laves phase alloys SO ACTA MATERIALIA LA English DT Article DE intermetallic compounds; lattice defects, vacancy; fracture and fractive roughness, hardness ID INTERMETALLIC COMPOUNDS; FRACTURE-TOUGHNESS; HYDROGEN AB Point defects in the binary C15 NbCr2 and NbCo2, and C14 NbFe2 systems on both sides of stoichiometry were studied by bulb; density and X-ray lattice parameter measurements. It was found that the vacancy concentrations in these systems after quenching from 1000 degrees C are essentially zero. The constitutional defects on both sides of stoichiometry for these systems were found to be of the anti-site type in comparison with model predictions. Thermal vacancies exhibiting a maximum at the stoichiometric composition were observed in NbCr2 Laves phase alloys after quenching from 1400 degrees C. However, there are essentially no thermal vacancies in NbFe2 alloys after quenching from 1300 degrees C. Anti-site hardening was found on both sides of stoichiometry for all the three Laves phase systems studied. Neither the anti-site defects nor the thermal vacancies affect the fracture toughness of the Laves phases significantly. (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd.! All rights reserved. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Mat Sci & Engn, Knoxville, TN 37996 USA. RP Zhu, JH (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. OI Liu, Chain Tsuan/0000-0001-7888-9725 NR 37 TC 55 Z9 63 U1 2 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 EI 1873-2453 J9 ACTA MATER JI Acta Mater. PD MAY 28 PY 1999 VL 47 IS 7 BP 2003 EP 2018 DI 10.1016/S1359-6454(99)00090-7 PG 16 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 205FX UT WOS:000080811600002 ER PT J AU Gabuda, SP Kozlova, SG Terskikh, VV Dybowski, C Neue, G Perry, DL AF Gabuda, SP Kozlova, SG Terskikh, VV Dybowski, C Neue, G Perry, DL TI Pb-207 NMR study of novel Pb-Pb chemical bonding in lead monoxides, alpha-PbO and beta-PbO SO CHEMICAL PHYSICS LETTERS LA English DT Article ID REFINEMENT AB alpha-PbO and beta-PbO have been studied with Pb-207 NMR-MAS spectroscopy in the solid state. The Pb-207 NMR chemical-shift tensor in alpha-PbO is axial, with principal values delta(perpendicular to) = 3030 +/- 5, delta(parallel to) = -270 +/- 5, and delta(iso) = 1930 +/- 10 ppm. In beta-PbO, the Pb-207 NMR powder spectrum is approximately represented by a single non-axial tensor with principal values delta(11) = 2820, delta(22) = 2760, delta(33) = -1000, delta(iso) = 1525 +/- 10 ppm and eta = 0.024, although there appears to be an overlap of two very similar patterns. Using normal-coordinate analysis, the Pb-207 magnetic shielding tensor is represented as a sum of contributions from separate Pb-O and Pb-Pb interactions. It is shown that Pb-O and Pb-Pb contributions are of the same order of magnitude. A potential underlying relativistic reason for the abnormal Pb-Pb interaction is revealed. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Russian Acad Sci, Inst Organ Chem, Novosibirsk 630090, Russia. Boreskov Inst Catalysis, Novosibirsk 630090, Russia. Univ Delaware, Dept Chem & Biochem, Newark, DE 19716 USA. Univ Dortmund, D-44221 Dortmund, Germany. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Gabuda, SP (reprint author), Russian Acad Sci, Inst Organ Chem, Novosibirsk 630090, Russia. NR 21 TC 19 Z9 20 U1 1 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD MAY 28 PY 1999 VL 305 IS 5-6 BP 353 EP 358 DI 10.1016/S0009-2614(99)00407-8 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 202AW UT WOS:000080630800007 ER PT J AU Brace, D Morariu, B AF Brace, D Morariu, B TI A note on the BPS spectrum of the matrix model SO JOURNAL OF HIGH ENERGY PHYSICS LA English DT Article DE string duality; M(atrix) theories; brane dynamics in gauge theories ID DUALITY AB We calculate, using noncommutative supersymmetric Yang-Mills gauge theory, the part of the spectrum of the toroidally compactified Matrix theory which corresponds to quantized electric fluxes on two and three tori. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RP Brace, D (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. EM brace@thwk2.lbl.gov; morariu@thsrv.lbl.gov NR 16 TC 33 Z9 33 U1 0 U2 0 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1029-8479 J9 J HIGH ENERGY PHYS JI J. High Energy Phys. PD MAY 28 PY 1999 IS 2 AR 004 PG 9 WC Physics, Particles & Fields SC Physics GA 204LX UT WOS:000080766700004 ER PT J AU Neubert, M AF Neubert, M TI Model-independent analysis of B -> pi K decays and bounds on the weak phase gamma SO JOURNAL OF HIGH ENERGY PHYSICS LA English DT Article DE B-physics; CP violation; rare decays; global symmetries ID CKM-ANGLE-GAMMA; FINAL-STATE INTERACTIONS; ISOSPIN ANALYSIS; B->PI-K DECAYS; PENGUIN CONTRIBUTIONS; ELECTROWEAK PENGUINS; CP ASYMMETRIES; MESONS; AMPLITUDES; PHYSICS AB A general parametrization of the amplitudes for the rare two-body decays B --> pi K is introduced, which makes maximal use of theoretical constraints arising from flavour symmetries of the strong interactions and the structure of the low-energy effective weak Hamiltonian. With the help of this parametrization, a model-independent analysis of the branching ratios and direct CP asymmetries in the various B --> pi K decay modes is performed, and the impact of hadronic uncertainties on bounds on the weak phase gamma = arg(V-ub*) is investigated. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Theory Grp, Stanford, CA 94309 USA. RP Neubert, M (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Theory Grp, Stanford, CA 94309 USA. EM neubert@slac.stanford.edu NR 48 TC 59 Z9 59 U1 0 U2 0 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1029-8479 J9 J HIGH ENERGY PHYS JI J. High Energy Phys. PD MAY 28 PY 1999 IS 2 AR 014 PG 36 WC Physics, Particles & Fields SC Physics GA 204LX UT WOS:000080766700014 ER PT J AU Owczarek, R AF Owczarek, R TI Spinor structures on flag manifolds of compact simple Lie groups SO JOURNAL OF PHYSICS A-MATHEMATICAL AND GENERAL LA English DT Article ID COADJOINT ORBITS; VORTICES; ALGEBRAS AB In this paper spinor structures over flag manifolds of compact simple Lie groups are considered and constructed explicitly using the general method of Dabrowski and Trautman. In this way the existence and uniqueness of these structures is established, in accordance with purely topological results of Freed. Application of the structures for further studies of fermionic excitations in theories with coadjoint orbits as phase spaces, including infinite-dimensional systems such as superfluid helium, is suggested. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Owczarek, R (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, T-13,MS B213, Los Alamos, NM 87545 USA. NR 20 TC 1 Z9 1 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0305-4470 J9 J PHYS A-MATH GEN JI J. Phys. A-Math. Gen. PD MAY 28 PY 1999 VL 32 IS 21 BP 3979 EP 3991 DI 10.1088/0305-4470/32/21/310 PG 13 WC Physics, Multidisciplinary; Physics, Mathematical SC Physics GA 204YV UT WOS:000080794500011 ER PT J AU Snell, G Drescher, M Muller, N Heinzmann, U Hergenhahn, U Becker, U AF Snell, G Drescher, M Muller, N Heinzmann, U Hergenhahn, U Becker, U TI Spin-resolved electron spectroscopy of the xenon N4,5O2,3O2,3 Auger lines SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID NOBLE-GAS ATOMS; ANGULAR-DISTRIBUTION; SYNCHROTRON RADIATION; HELICAL UNDULATOR; X-RAYS; POLARIZATION; PHOTOIONIZATION; POLARIMETER; IONIZATION; EXCITATION AB The spin polarization of the Xe N4,5O2,3O2,3 Auger lines was measured after ionization by circularly polarized synchrotron radiation of 93.8 eV photon energy. The circularly polarized radiation was produced by converting the linearly polarized light from a conventional undulator by a Mo/Si transmission multilayer acting as a quarter-wave plate. Nearly perfect circular polarization was obtained. In the framework of the two-step model of Auger decay the orientation of the primary hole stales 4d(-1) D-2(3/2) and 4d(-1) D-2(s/2) can be derived from the spin polarization of the S-1(0) Auger lines. Furthermore, the intrinsic parameters for all lines in this Auger group corresponding to the other 5p(-2) final states are determined and compared with theory. C1 Univ Bielefeld, D-33501 Bielefeld, Germany. Max Planck Gesell, Fritz Haber Inst, D-14195 Berlin, Germany. RP Snell, G (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RI Heinzmann, Ulrich/A-6248-2012; Becker, Uwe/A-6604-2013 NR 37 TC 17 Z9 17 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD MAY 28 PY 1999 VL 32 IS 10 BP 2361 EP 2369 DI 10.1088/0953-4075/32/10/306 PG 9 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 204EB UT WOS:000080749200008 ER PT J AU Krstic, PS Schultz, DR AF Krstic, PS Schultz, DR TI Elastic and vibrationally inelastic slow collisions: H+H-2, H++H-2 SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID CHARGE-TRANSFER PROCESSES; POTENTIAL-ENERGY SURFACE; CROSS-SECTIONS; HYDROGEN-ATOMS; SCATTERING; H+; EXCITATION; H-2 AB We report on a comprehensive study of the scattering of hydrogen atoms on the ground electronic surface of hydrogen molecules in the range of centre of mass energies 0.1-100 eV. Differential and integral elastic cross sections, the related transport cross sections, and vibrationally inelastic cross sections starting from both ground and excited vibrational states, are calculated using a fully quantal, coupled-channel approach in a truncated vibrational basis set while the rotational dynamics of H-2? is treated with the infinite order sudden approximation prescription. For comparison and to highlight the major physical mechanisms revealed in these collisions, a parallel study is carried out for scattering of protons on hydrogen molecules. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. RP Krstic, PS (reprint author), Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. NR 25 TC 44 Z9 44 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD MAY 28 PY 1999 VL 32 IS 10 BP 2415 EP 2431 DI 10.1088/0953-4075/32/10/310 PG 17 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 204EB UT WOS:000080749200012 ER PT J AU Volkow, ND Wang, J Fowler, JS Fischman, M Foltin, R Abumrad, NN Gatley, SJ Logan, J Wong, C Gifford, A Ding, YS Hitzemann, R Pappas, N AF Volkow, ND Wang, J Fowler, JS Fischman, M Foltin, R Abumrad, NN Gatley, SJ Logan, J Wong, C Gifford, A Ding, YS Hitzemann, R Pappas, N TI Methylphenidate and cocaine have a similar in vivo potency to block dopamine transporters in the human brain SO LIFE SCIENCES LA English DT Article DE addiction; reinforcement; imaging; PET; ADHD ID BINDING; OCCUPANCY; PET AB The reinforcing effects of cocaine and methylphenidate have been linked to their ability to block dopamine transporters (DAT). Though cocaine and methylphenidate have similar in vitro affinities for DAT the abuse of methylphenidate in humans is substantially lower than of cocaine. To test if differences in in vivo potency at the DAT between these two drugs could account for the differences in their abuse liability we compared the levels of DAT occupancies that we had previously reported separately for intravenous methylphenidate in controls and for intravenous cocaine in cocaine abusers. DAT occupancies were measured with Positron Emission Tomography using [C-11]cocaine, as a DAT ligand, in 8 normal controls for the methylphenidate study and in 17 active cocaine abusers for the cocaine study. The ratio of the distribution volume of [C-11]cocaine in striatum to that in cerebellum, which corresponds to Bmax/Kd +1, was used as measure of DAT availability. Parallel measures were obtained to assess the cardiovascular effects of these two drugs. Methylphenidate and cocaine produced comparable dose-dependent blockade of DAT with an estimated ED50 (dose required to block 50% of the DAT) for methylphenidate of 0.07 mg/kg and for cocaine of 0.13 mg/kg. Both drugs induced similar increases in heart rate and blood pressure but the duration of the effects were significantly longer for methylphenidate than for cocaine. The similar in vivo potencies at the DAT for methylphenidate than for cocaine are in agreement with their reported relative in vitro affinities (Ki 390 nM and 640 nM respectively), which is likely to reflect the similar degree of uptake (8-10% of the injected dose) and regional distribution of these two drags in the human brain. Thus, differences in the in vivo potency of these two drugs at the DAT cannot be responsible for the differences in their rate of abuse in humans. Other variables i.e. longer duration of methylphenidate's side effects may counterbalance its reinforcing effects. (C) 1999 Elsevier Science Inc. C1 Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. SUNY Stony Brook, Dept Psychiat, Stony Brook, NY 11794 USA. Columbia Univ, Dept Psychiat, New York, NY 10032 USA. N Shore Univ Hosp, Dept Surg, Manhasset, NY 11030 USA. RP Volkow, ND (reprint author), Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. FU NIDA NIH HHS [DA09490-01] NR 21 TC 43 Z9 45 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0024-3205 J9 LIFE SCI JI Life Sci. PD MAY 28 PY 1999 VL 65 IS 1 BP PL7 EP PL12 DI 10.1016/S0024-3205(99)00225-8 PG 6 WC Medicine, Research & Experimental; Pharmacology & Pharmacy SC Research & Experimental Medicine; Pharmacology & Pharmacy GA 206WJ UT WOS:000080903100013 PM 10403500 ER PT J AU Baker, RT Tumas, W AF Baker, RT Tumas, W TI Homogeneous catalysis - Toward greener chemistry SO SCIENCE LA English DT Editorial Material ID PHASE CATALYSIS; HYDROFORMYLATION; SEPARATION C1 Univ Calif Los Alamos Natl Lab, Los Alamos Catalysis Initiat, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Baker, RT (reprint author), Univ Calif Los Alamos Natl Lab, Los Alamos Catalysis Initiat, POB 1663, Los Alamos, NM 87545 USA. NR 20 TC 119 Z9 124 U1 0 U2 20 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAY 28 PY 1999 VL 284 IS 5419 BP 1477 EP 1479 DI 10.1126/science.284.5419.1477 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 200PD UT WOS:000080548100024 ER PT J AU Bahcall, NA Ostriker, JP Perlmutter, S Steinhardt, PJ AF Bahcall, NA Ostriker, JP Perlmutter, S Steinhardt, PJ TI Cosmology - The cosmic triangle: Revealing the state of the universe SO SCIENCE LA English DT Review ID COLD DARK-MATTER; MICROWAVE BACKGROUND ANISOTROPY; LIGHT-CURVE SHAPES; INFLATIONARY UNIVERSE; IA SUPERNOVAE; GALAXY CLUSTERS; LARGE-SCALE; GRAVITATIONAL LENSES; GLOBULAR-CLUSTERS; GRAVITY-WAVES AB The cosmic triangle is introduced as a way of representing the past, present, and future status of the universe. Our current location within the cosmic triangle is determined by the answers to three questions: How much matter is in the universe? Is the expansion rate stowing down or speeding up? And, is the universe flat? A review of recent observations suggests a universe that is lightweight (matter density about one-third the critical value), is accelerating, and is flat. The acceleration implies the existence of cosmic dark energy that overcomes the gravitational self-attraction of matter and causes the expansion to speed up. C1 Princeton Univ Observ, Princeton, NJ 08544 USA. Ernest Orlando Lawrence Berkeeley Natl Lab, Inst Nucl & Particle Astrophys, Berkeley, CA 94720 USA. Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. RP Bahcall, NA (reprint author), Princeton Univ Observ, Peyton Hall, Princeton, NJ 08544 USA. EM neta@astro.princeton.edu RI Perlmutter, Saul/I-3505-2015 OI Perlmutter, Saul/0000-0002-4436-4661 NR 114 TC 802 Z9 805 U1 3 U2 25 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAY 28 PY 1999 VL 284 IS 5419 BP 1481 EP 1488 DI 10.1126/science.284.5419.1481 PG 10 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 200PD UT WOS:000080548100027 ER PT J AU Remington, BA Arnett, D Drake, RP Takabe, H AF Remington, BA Arnett, D Drake, RP Takabe, H TI Experimental astrophysics - Modeling astrophysical phenomena in the laboratory with intense lasers SO SCIENCE LA English DT Review ID GAMMA-RAY BURSTS; SUPERNOVA REMNANT; X-RAY; CYGNUS LOOP; TEMPERATURE-MEASUREMENTS; SPECTRAL EVOLUTION; STATE MEASUREMENTS; LIQUID DEUTERIUM; II SUPERNOVAE; GIANT PLANETS AB Astrophysical research has traditionally been divided into observations and theoretical modeling or a combination of both, A component sometimes missing has been the ability to quantitatively test the observations and models in an experimental setting where the initial and final states are well characterized. Intense lasers are now being used to recreate aspects of astrophysical phenomena in the laboratory, allowing the creation of experimental test beds where observations and models can be quantitatively compared with laboratory data. Experiments are under development at intense laser facilities to test and refine our understanding of phenomena such as supernovae, supernova remnants, gamma-ray bursts, and giant planets. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Osaka Univ, Inst Laser Engn, Suita, Osaka 565, Japan. RP Remington, BA (reprint author), Univ Calif Lawrence Livermore Natl Lab, L021, Livermore, CA 94550 USA. RI Drake, R Paul/I-9218-2012 OI Drake, R Paul/0000-0002-5450-9844 NR 64 TC 241 Z9 247 U1 5 U2 32 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAY 28 PY 1999 VL 284 IS 5419 BP 1488 EP 1493 DI 10.1126/science.284.5419.1488 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 200PD UT WOS:000080548100028 ER PT J AU Kao, CYJ Smith, WS AF Kao, CYJ Smith, WS TI Sensitivity of a cloud parameterization package in the National Center for Atmospheric Research Community Climate Model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GENERAL-CIRCULATION MODEL; SCHUBERT CUMULUS PARAMETERIZATION; WEATHER PREDICTION MODEL; EARTH RADIATION BUDGET; SURFACE TEMPERATURE; WATER-CONTENT; SCHEME; CCM2; PRECIPITATION; CONDENSATION AB A physically based cloud parameterization package, which includes the Arakawa-Schubert (AS) scheme for subgrid-scale convective clouds and the Sundqvist (SUN) scheme for nonconvective grid-scale layered clouds (hereafter referred to as the SUNAS cloud package), is incorporated into the National Center for Atmospheric Research (NCAR) Community Climate Model, Version 2 (CCM2). The AS scheme is used for a more reasonable heating distribution due to convective clouds and their associated precipitation. The SUN scheme allows for the prognostic computation of cloud water so that the cloud optical properties are more physically determined for shortwave and longwave radiation calculations. In addition, the formation of anvil-like clouds from deep convective systems is able to be simulated with the SUNAS package. A 10-year simulation spanning the period from 1980 to 1989 is conducted, and the effect of the cloud package on the January climate is assessed by comparing it with various available data sets and the National Center for Environmental Protection/NCAR reanalysis. Strengths and deficiencies of both the SUN and AS methods are identified and discussed. The AS scheme improves some aspects of the model dynamics and precipitation, especially with respect to the Pacific North America (PNA) pattern. CCM2's tendency to produce a westward bias of the 500 mbar stationary wave (time-averaged zonal anomalies) in the PNA sector is remedied apparently because of a less "locked-in" heating pattern ill the tropics. The additional degree of freedom added by the prognostic calculation of cloud water in the SUN scheme produces interesting results in the modeled cloud and radiation fields compared with data. In general, too little cloud water forms in the tropics, while excessive cloud cover and cloud liquid water are simulated in midlatitudes. This results in a somewhat degraded simulation of the radiation budget. The overall simulated precipitation by the SUNAS package is, however, substantially improved over the original CCM2. C1 Los Alamos Natl Lab, Div Earth & Environm Sci EES8, Los Alamos, NM 87544 USA. Univ Calif San Diego, Div Climate Res, Scripps Inst Oceanog, La Jolla, CA 92093 USA. RP Los Alamos Natl Lab, Div Earth & Environm Sci EES8, MS C300, Los Alamos, NM 87544 USA. EM kao@vega.lanl.gov; wss@vega.lanl.gov NR 44 TC 1 Z9 1 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 27 PY 1999 VL 104 IS D10 BP 11961 EP 11983 DI 10.1029/1999JD900079 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 200XX UT WOS:000080566500008 ER PT J AU Lyman, JL Newnam, BE Noda, T Suzuki, H AF Lyman, JL Newnam, BE Noda, T Suzuki, H TI Enrichment of silicon isotopes with infrared free-electron laser radiation SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID MULTIPLE-PHOTON DECOMPOSITION; FORMIC-ACID MOLECULES; MULTIPHOTON DISSOCIATION; SELECTIVE DISSOCIATION; SI2F6; HEXAFLUORODISILANE; IRRADIATION; GAS AB We have used the FELIX infrared free-electron laser (FEL) at the FOM Institute for Plasma Physics in The Netherlands to enrich silicon isotopes by multiple-photon dissociation of the molecule Si2F6. The absorption of infrared radiation induces the reaction Si2F6 --> SiF4 + SiF2. Much of the SiF2 product further reacts to form additional SiF4. The Si2F6 molecule has absorption bands in the 10, 12, and 25 mu m spectral regions. FEL-induced reactions occurred in all three regions. The reaction fraction was highest for the stronger band in the 10 mu m region. Reactions in all three bands were isotopically selective. Irradiation in the 10 mu m region at 952 cm(-1) gave an isotopic selectivity of 5.6 for Si-30. For comparison, the published isotopic selectivity using a CO2 laser in the same spectral region is in excess of 17. Wi: attribute the lower selectivity obtained with an FEL to its longer macropulse, its broader spectral width, and differences in experimental procedure. FEL irradiation in the region of the 12 mu m band produced isotopic selectivities in excess of 20 for Si-30. Selective production of Si-28 was high in the 25 mu m region. We used changes in the infrared spectra of the irradiated samples for all analyses of reaction and isotope enrichment except for a single confirmation of enrichment with a mass spectrometer. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Natl Res Inst Met, Ibaraki, Osaka 305, Japan. RP Lyman, JL (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 23 TC 29 Z9 30 U1 1 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 27 PY 1999 VL 103 IS 21 BP 4227 EP 4232 DI 10.1021/jp984699v PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 202HP UT WOS:000080646500015 ER PT J AU Labouriau, A Pietrass, T Weber, WA Gates, BC Earl, WL AF Labouriau, A Pietrass, T Weber, WA Gates, BC Earl, WL TI Temperature dependence of nuclear magnetic resonance chemical shifts of Xe-129 in the alpha-cages of NaY zeolite SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID SODIUM-Y-ZEOLITE; MOLECULAR-DYNAMICS; MICROPOROUS SOLIDS; NMR-SPECTROSCOPY; SELF-DIFFUSION; XENON; ADSORPTION; SIMULATIONS; CLUSTERS; LOCATION AB One- and two-dimensional NMR spectra of Xe-129 sorbed in NaY zeolite at a loading of approximately 1 Xe atom/4 alpha-cages were obtained as a function of temperature. One-dimensional spectra were measured over the range of 60-300 K, by far the largest range yet investigated with this method. The data were fitted to the simple statistical mechanical cylindrical pore model of Cheung yielding a van der Waals adsorption energy of 3.3 kJ/mol. 2D-NOESY spectra were obtained at 300 and 355 K. The two-dimensional data show that the intercrystalline diffusion is slow compared to intracrystalline diffusion. The results indicate that the Xe atoms spend most of their time in the or-cages and at the lower temperatures, near the cage walls. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. New Mexico Inst Min & Technol, Dept Chem, Socorro, NM 87801 USA. Univ Calif Davis, Dept Chem Engn & Mat Sci, Davis, CA 95616 USA. RP Labouriau, A (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Mail Stop J514, Los Alamos, NM 87545 USA. NR 48 TC 13 Z9 13 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 27 PY 1999 VL 103 IS 21 BP 4323 EP 4329 DI 10.1021/jp9846835 PG 7 WC Chemistry, Physical SC Chemistry GA 202HR UT WOS:000080646700016 ER PT J AU Cui, ST Cochran, HD Cummings, PT AF Cui, ST Cochran, HD Cummings, PT TI Vapor-liquid phase coexistence of alkane carbon dioxide and perfluoroalkane carbon dioxide mixtures SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID INTERMOLECULAR POTENTIALS; MONTE-CARLO; EQUILIBRIA; MICROEMULSIONS; SIMULATION; BEHAVIOR; WATER; POLYMERIZATION; AOT; FLUOROPOLYMERS AB We carried out a molecular simulation study of the vapor-liquid equilibria of alkane-CO2 and perfluoro-alkane-CO2 binary mixtures using the Gibbs ensemble Monte Carlo method. We used simple interaction site models and the conventional Lorentz-Berthelot combining rules for the cross interaction between the solute and solvent species with no adjustable parameters to predict the vapor-liquid phase equilibrium of the hexane-CO2 and perfluorohexane-CO2 mixtures. The predicted CO2 mole fraction on the liquid branch is higher than the experimental results by about 10-13%. The gas-phase solubility of hexane and perfluorohexane in CO2 is generally smaller than the experimental results. The model predicts a higher solubility for the perfluoroalkanes in CO2 in comparison with alkanes in CO2, consistent with experiment. The simulation results suggest that the dispersion interaction and the geometric packing may have a predominant role in accounting for the solubility difference between alkane and perfluoroalkane in CO2. C1 Univ Tennessee, Dept Chem Engn, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. RP Cui, ST (reprint author), Univ Tennessee, Dept Chem Engn, Knoxville, TN 37996 USA. RI Cummings, Peter/B-8762-2013 OI Cummings, Peter/0000-0002-9766-2216 NR 43 TC 62 Z9 64 U1 1 U2 15 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 27 PY 1999 VL 103 IS 21 BP 4485 EP 4491 DI 10.1021/jp984147c PG 7 WC Chemistry, Physical SC Chemistry GA 202HR UT WOS:000080646700040 ER PT J AU Backhaus, S Swift, GW AF Backhaus, S Swift, GW TI A thermoacoustic Stirling heat engine SO NATURE LA English DT Article ID TUBE AB Electrical and mechanical power, together with other forms of useful work, are generated worldwide at a rate of about 10(12) watts, mostly using heat engines. The efficiency of such engines is limited by the laws of thermodynamics and by practical considerations such as the cost of building and operating them. Engines with high efficiency help to conserve fossil fuels and other natural resources, reducing global-warming emissions and pollutants. In practice, the highest efficiencies are obtained only in the most expensive, sophisticated engines, such as the turbines in central utility electrical plants. Here we demonstrate an inexpensive thermoacoustic engine that employs the inherently efficient Stirling cycle(1). The design is based on a simple acoustic apparatus with no moving parts. Our first small laboratory prototype, constructed using inexpensive hardware (steel pipes), achieves an efficiency of 0.30, which exceeds the values of 0.10-0.25 attained in other heat engines(5,6) with no moving parts. Moreover, the efficiency of our prototype is comparable to that of the common internal combustion engine(2) (0.25-0.40) and piston-driven Stirling engines(3,4) 4 (0.20-0.38). C1 Univ Calif Los Alamos Natl Lab, Condensed Matter & Thermal Phys Grp, Los Alamos, NM 87545 USA. RP Backhaus, S (reprint author), Univ Calif Los Alamos Natl Lab, Condensed Matter & Thermal Phys Grp, Los Alamos, NM 87545 USA. RI Backhaus, Scott/F-4285-2012 NR 20 TC 289 Z9 356 U1 15 U2 85 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAY 27 PY 1999 VL 399 IS 6734 BP 335 EP 338 DI 10.1038/20624 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 200PA UT WOS:000080547800053 ER PT J AU Ybe, JA Brodsky, FM Hofmann, K Lin, K Liu, SH Chen, L Earnest, TN Fletterick, RJ Hwang, PK AF Ybe, JA Brodsky, FM Hofmann, K Lin, K Liu, SH Chen, L Earnest, TN Fletterick, RJ Hwang, PK TI Clathrin self-assembly is mediated by a tandemly repeated superhelix SO NATURE LA English DT Article ID PROTEIN COMPLEX; TRIMERIZATION; RESOLUTION; PROGRAM; ALPHA; CHAIN AB Clathrin is a triskelion-shaped cytoplasmic protein that polymerizes into a polyhedral lattice on intracellular membranes to form protein-coated membrane vesicles. Lattice formation induces the sorting of membrane proteins during endocytosis and organelle biogenesis by interacting with membrane-associated adaptor molecules(1). The clathrin triskelion is a trimer of heavy-chain subunits (1,675 residues), each binding a single light-chain subunit, in the hub domain (residues 1,074-1,675), Light chains negatively modulate polymerization so that intracellular clathrin assembly is adaptor-dependent(2). Here we report the atomic structure, to 2.6 Angstrom resolution, of hub residues 1,210-1,516 involved in mediating spontaneous clathrin heavy-chain polymerization and light-chain association(3,4), The hub fragment folds into an elongated coil of alpha-helices, and alignment analyses reveal a 145-residue motif that is repeated seven times along the filamentous leg and appears in other proteins involved in vacuolar protein sorting. The resulting model provides a three-dimensional framework for understanding clathrin heavy-chain self-assembly, light-chain binding and trimerization. C1 Univ Calif San Francisco, Dept Microbiol & Immunol, GW Hooper Fdn, San Francisco, CA 94143 USA. Univ Calif San Francisco, Dept Biopharmaceut Sci, San Francisco, CA 94143 USA. Univ Calif San Francisco, Dept Pharmaceut Chem, San Francisco, CA 94143 USA. Univ Calif San Francisco, Dept Biochem & Biophys, San Francisco, CA 94143 USA. MEMOREC Stoffel Gmbh, Bioinformat Grp, D-50829 Koeln, Germany. Lawrence Berkeley Natl Lab, Phys Biosci Div, Adv Light Source, Macromol Crystallog Facil, Berkeley, CA 94720 USA. RP Brodsky, FM (reprint author), Univ Calif San Francisco, Dept Microbiol & Immunol, GW Hooper Fdn, San Francisco, CA 94143 USA. RI Hofmann, Kay/D-6714-2011 OI Hofmann, Kay/0000-0002-2289-9083 NR 30 TC 114 Z9 114 U1 0 U2 9 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAY 27 PY 1999 VL 399 IS 6734 BP 371 EP 375 DI 10.1038/20708 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 200PA UT WOS:000080547800063 PM 10360576 ER PT J AU Zhang, LQ Ramratnam, B Tenner-Racz, K He, YX Vesanen, M Lewin, S Talal, A Racz, P Perelson, AS Korber, BT Markowitz, M Ho, DD AF Zhang, LQ Ramratnam, B Tenner-Racz, K He, YX Vesanen, M Lewin, S Talal, A Racz, P Perelson, AS Korber, BT Markowitz, M Ho, DD TI Quantifying residual HIV-1 replication in patients receiving combination antiretroviral therapy SO NEW ENGLAND JOURNAL OF MEDICINE LA English DT Article ID IMMUNODEFICIENCY-VIRUS TYPE-1; PRIMARY INFECTION; RAPID TURNOVER; CELL COUNTS; LIFE-SPAN; T-CELLS; LYMPHOCYTES; SEQUENCES; INDINAVIR; POOL AB Background In patients infected with human immunodeficiency virus type 1 (HIV-1), combination antiretroviral therapy can result in sustained suppression of plasma levels of the virus. However, replication-competent virus can still be recovered from latently infected resting memory CD4 lymphocytes; this finding raises serious doubts about whether antiviral treatment can eradicate HIV-1. Methods We looked for evidence of residual HIV-1 replication in eight patients who began treatment soon after infection and in whom plasma levels of HIV-I RNA were undetectable after two to three years of antiretroviral therapy. We examined whether there had been changes over time in HIV-1 proviral sequences in peripheral-blood mononuclear eel Is, which would indicate residual viral replication. We also performed in situ hybridization studies on tissues from one patient to identify cells actively expressing HIV-1 RNA. We estimated the rate of decrease of latent, replication-competent HIV-1 in resting CD4 lymphocytes on the basis of the decrease in the numbers of proviral sequences identified during primary infection and direct sequential measurements of the size of the latent reservoir. Results Six of the eight patients had no significant variations in proviral sequences during treatment. However, in two patients there was sequence evolution but no evidence of drug-resistant viral genotypes. In one patient, extensive in situ studies provided additional evidence of persistent viral replication in lymphoid tissues. Using two independent approaches, we estimated that the half-life of the latent, replication-competent virus in resting CD4 lymphocytes was approximately six months. Conclusions These findings suggest that combination antiretroviral regimens suppress HIV-1 replication in some but not all patients. Given the half-life of latently infected CD4 lymphocytes of about six months, it may require many years of effective antiretroviral treatment to eliminate this reservoir of HIV-1. (N Engl J Med 1999;340:1605-13.) (C) 1999, Massachusetts Medical Society. C1 Rockefeller Univ, Aaron Diamond AIDS Res Ctr, New York, NY 10016 USA. Bernhard Nocht Inst Trop Med, Hamburg, Germany. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM USA. RP Ho, DD (reprint author), Rockefeller Univ, Aaron Diamond AIDS Res Ctr, 455 1st Ave, New York, NY 10016 USA. OI Korber, Bette/0000-0002-2026-5757; Lewin, Sharon Ruth/0000-0002-0330-8241 FU NCRR NIH HHS [MO1-RR00102]; NIAID NIH HHS [AI40387, AI41534] NR 24 TC 632 Z9 639 U1 1 U2 6 PU MASSACHUSETTS MEDICAL SOC PI WALTHAM PA WALTHAM WOODS CENTER, 860 WINTER ST,, WALTHAM, MA 02451-1413 USA SN 0028-4793 J9 NEW ENGL J MED JI N. Engl. J. Med. PD MAY 27 PY 1999 VL 340 IS 21 BP 1605 EP 1613 DI 10.1056/NEJM199905273402101 PG 9 WC Medicine, General & Internal SC General & Internal Medicine GA 199QY UT WOS:000080494200001 PM 10341272 ER PT J AU Furtado, MR Callaway, DS Phair, JP Kunstman, KJ Stanton, JL Macken, CA Perelson, AS Wolinsky, SM AF Furtado, MR Callaway, DS Phair, JP Kunstman, KJ Stanton, JL Macken, CA Perelson, AS Wolinsky, SM TI Persistence of HIV-1 transcription in peripheral-blood mononuclear cells in patients receiving potent antiretroviral therapy SO NEW ENGLAND JOURNAL OF MEDICINE LA English DT Article ID IMMUNODEFICIENCY-VIRUS TYPE-1; DYNAMICS IN-VIVO; RNA EXPRESSION; LYMPHOID-TISSUES; VIRAL LOAD; INFECTION; LYMPHOCYTES; RESERVOIR; LATENCY; INDIVIDUALS AB Background and Methods Although potent antiretroviral therapy can control infection with human immunodeficiency virus type 1 (HIV-1), a long-lived reservoir of infectious virus persists in CD4+ T cells. We investigated this viral reservoir by measuring the levels of cell-associated viral DNA and messenger RNA (mRNA) that are essential for HIV-1 replication. Approximately every 6 months, we obtained samples of peripheral-blood mononuclear cells from five men with long-standing HIV-1 infection who had had undetectable levels of plasma HIV-1 RNA for 20 months or more during treatment with potent antiretroviral drugs. Results Before treatment, plasma levels of HIV-1 RNA correlated with the levels of cell-associated unintegrated HIV-1 DNA and unspliced viral mRNA. After treatment, plasma levels of HIV-1 RNA fell by more than 2.7 log to undetectable levels. The decrease in cell-associated integrated and unintegrated HIV-1 DNA and mRNA occurred in two phases. The first phase occurred during the initial 500 days of treatment and was characterized by substantial decreases in the levels of DNA and mRNA, but not to undetectable levels. The concentrations of cell-associated unintegrated viral DNA, integrated proviral DNA, and unspliced viral mRNA decreased by 1.25 to 1.46 log. The second phase occurred during the subsequent 300 days or more of treatment and was characterized by a plateau in the levels of HIV-1 DNA and unspliced mRNA. After an initial rapid decline, the ratio of unspliced to multiply spliced viral mRNA (a measure of active viral transcription) stabilized and remained greater than zero at each measurement. Conclusions Despite treatment with potent antiretroviral drugs and the suppression of plasma HIV-1 RNA to undetectable levels for 20 months or more, HIV-1 transcription persists in peripheral-blood mononuclear cells. Unless the quasi-steady state levels of HIV DNA and mRNA eventually disappear with longer periods of therapy, these findings suggest that HIV-1 infection cannot be eradicated with current treatments. (N Engl J Med 1999;340:1614-22.) (C) 1999, Massachusetts Medical Society. C1 Northwestern Univ, Sch Med, Dept Med, Div Infect Dis, Chicago, IL 60611 USA. Northwestern Univ, Sch Med, Dept Pathol, Chicago, IL 60611 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM USA. RP Wolinsky, SM (reprint author), Northwestern Univ, Sch Med, Dept Med, Div Infect Dis, Tarry 3-735,303 E Chicago Ave, Chicago, IL 60611 USA. RI Wolinsky, Steven/B-2893-2012; OI Wolinsky, Steven/0000-0002-9625-6697 FU NCRR NIH HHS [RR06555]; NIAID NIH HHS [AI035039]; NICHD NIH HHS [HD37356-01] NR 35 TC 491 Z9 497 U1 1 U2 9 PU MASSACHUSETTS MEDICAL SOC PI WALTHAM PA WALTHAM WOODS CENTER, 860 WINTER ST,, WALTHAM, MA 02451-1413 USA SN 0028-4793 J9 NEW ENGL J MED JI N. Engl. J. Med. PD MAY 27 PY 1999 VL 340 IS 21 BP 1614 EP 1622 DI 10.1056/NEJM199905273402102 PG 9 WC Medicine, General & Internal SC General & Internal Medicine GA 199QY UT WOS:000080494200002 PM 10341273 ER PT J AU Boggild, H Boissevain, J Dodd, J Esumi, S Fabjan, CW Ferenc, D Franz, A Hardtke, D van Hecke, H Humanic, TJ Ikemoto, T Jacak, BV Kalechofsky, H Kobayashi, T Kvatadze, R Lee, YY Leltchouk, M Lorstad, B Maeda, N Miake, Y Miyabayashi, A Murray, M Nagamiya, S Nishimura, S Paic, G Pandey, SU Piuz, F Polychronakos, V Potekhin, M Poulard, G Rahm, D Rieubland, JM Sakaguchi, A Sarabura, M Shigaki, K Simon-Gillo, J Schmidt-Sorensen, J Sondheim, W Sugitate, T Sullivan, JP Sumi, Y Willis, WJ AF Boggild, H Boissevain, J Dodd, J Esumi, S Fabjan, CW Ferenc, D Franz, A Hardtke, D van Hecke, H Humanic, TJ Ikemoto, T Jacak, BV Kalechofsky, H Kobayashi, T Kvatadze, R Lee, YY Leltchouk, M Lorstad, B Maeda, N Miake, Y Miyabayashi, A Murray, M Nagamiya, S Nishimura, S Paic, G Pandey, SU Piuz, F Polychronakos, V Potekhin, M Poulard, G Rahm, D Rieubland, JM Sakaguchi, A Sarabura, M Shigaki, K Simon-Gillo, J Schmidt-Sorensen, J Sondheim, W Sugitate, T Sullivan, JP Sumi, Y Willis, WJ CA NA44 Collaboration TI Three-pion correlations in sulphur-lead collisions at the CERN SPS SO PHYSICS LETTERS B LA English DT Article ID BOSE-EINSTEIN CORRELATIONS; HEAVY-ION COLLISIONS; INTERFEROMETRY; DEPENDENCE AB pi(+) pi(+) pi(+) correlations from sulphur-lead collisions at 200 GeV/c per nucleon are presented as measured by the focusing spectrometer of experiment NA44 at CERN. We have investigated the three-pion correlation function at mid-rapidity and found that a genuine three-body correlation is suppressed. A possible interpretation of this result is that the emission of particles is partially coherent. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Niels Bohr Inst, DK-2100 Copenhagen, Denmark. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Columbia Univ, New York, NY 10027 USA. Hiroshima Univ, Higashihiroshima 739, Japan. CERN, CH-1211 Geneva 23, Switzerland. Rudjer Boskovic Inst, Zagreb, Croatia. Brookhaven Natl Lab, Upton, NY 11973 USA. Ohio State Univ, Dept Phys, Columbus, OH 43210 USA. SUNY Stony Brook, Stony Brook, NY 11794 USA. Riken Linac Lab, Wako, Saitama 35101, Japan. Lund Univ, S-22362 Lund, Sweden. Univ Tsukuba, Tsukuba, Ibaraki 305, Japan. Texas A&M Univ, College Stn, TX 77843 USA. RP Niels Bohr Inst, Blegdamsvej 17, DK-2100 Copenhagen, Denmark. NR 25 TC 37 Z9 37 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 EI 1873-2445 J9 PHYS LETT B JI Phys. Lett. B PD MAY 27 PY 1999 VL 455 IS 1-4 BP 77 EP 83 DI 10.1016/S0370-2693(99)00402-5 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 209QQ UT WOS:000081060100013 ER PT J AU Molina-Paris, C Visser, M AF Molina-Paris, C Visser, M TI Minimal conditions for the creation of a Friedman-Robertson-Walker universe from a ''bounce'' SO PHYSICS LETTERS B LA English DT Article ID ENERGY CONDITION; GENERAL-RELATIVITY; GALAXY FORMATION; SINGULARITIES; INFLATION; WORMHOLES; AVOIDANCE; EPOCH AB In this Letter we investigate the minimal conditions under which the creation of our universe might arise due to a "bounce" from a previous collapse, rather than an explosion from a big-bang singularity. Such a bounce is sometimes referred to as a Tolman wormhole. We subject the bounce to a general model-independent analysis along the Lines of that applied to the Morris-Thorne traversable wormholes, and show that there is always an open temporal region surrounding the bounce over which the strong energy condition (SEC) must be violated. On the other hand, all the other energy conditions can easily be satisfied. In particular, we exhibit an inflation-inspired model in which a big bounce is "natural". (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Washington Univ, Dept Phys, St Louis, MO 63130 USA. RP Molina-Paris, C (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, POB 1663, Los Alamos, NM 87545 USA. OI Visser, Matt/0000-0003-1088-6485 NR 30 TC 61 Z9 62 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD MAY 27 PY 1999 VL 455 IS 1-4 BP 90 EP 95 DI 10.1016/S0370-2693(99)00469-4 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 209QQ UT WOS:000081060100015 ER PT J AU Jaffe, RL Kharzeev, D AF Jaffe, RL Kharzeev, D TI Chi(2) production in polarized pp collisions at RHIC: measuring Delta G and testing the color octet model SO PHYSICS LETTERS B LA English DT Article ID B-QUARK PRODUCTION; = 1.8 TEV; P(P)OVER-BAR COLLISIONS; ROOT-S=1.8 TEV; J-PSI; (P)OVER-BAR-P COLLISIONS; HADRONIC COLLISIONS; UPSILON-PRODUCTION; HEAVY QUARKONIUM; J/PSI PRODUCTION AB We consider the production and decay of the chi(2) charmonium state in polarized and unpolarized pp collisions at RHIC in the framework of an effective theory based on the QCD multipole expansion. We find that the angular distribution in the decay of the produced charmonium, chi(2) --> J/psi + gamma, in the unpolarized case allows us to distinguish clearly between the color singlet and color octet production mechanisms. Once the production mechanism is known, the angular distribution in the polarized case can be used to measure the polarized gluon distribution in the proton, Delta G(x). (C) 1999 Elsevier Science B.V. All rights reserved. C1 MIT, Ctr Theoret Phys, Nucl Sci Lab, Cambridge, MA 02139 USA. Brookhaven Natl Lab, RIKEN, BNL Res Ctr, Upton, NY 11973 USA. RP Jaffe, RL (reprint author), MIT, Ctr Theoret Phys, Nucl Sci Lab, Cambridge, MA 02139 USA. NR 28 TC 9 Z9 9 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD MAY 27 PY 1999 VL 455 IS 1-4 BP 306 EP 310 DI 10.1016/S0370-2693(99)00448-7 PG 5 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 209QQ UT WOS:000081060100045 ER PT J AU Vander Griend, DA Boudin, S Caignaert, V Poeppelmeier, KR Wang, YG Dravid, VP Azuma, M Takano, M Hu, ZB Jorgensen, JD AF Vander Griend, DA Boudin, S Caignaert, V Poeppelmeier, KR Wang, YG Dravid, VP Azuma, M Takano, M Hu, ZB Jorgensen, JD TI La4Cu3MoO12: A novel cuprate with unusual magnetism SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID CRYSTAL-STRUCTURE; PEROVSKITE AB La4Cu3MoO12 is a new (ABO(3))(n=4) cuprate with mixed B-cations in a ratio of 1:3. When synthesized at ambient pressure, the structure is not perovskite as expected but rather a homeotype of YAlO3, a rare-earth hexagonal phase. While the P6(3)/mmc and Pmnm space groups can be used to model average structures which appear in quenched samples; powder, electron, and neutron diffraction data all confirm that a slow-cooled sample crystallizes in the monoclinic space group, P112(1)/m. The copper and molybdenum are coordinated by oxygen in corner-sharing trigonal bipyramids that are sandwiched between layers of lanthanum cations. In the B-cation layer, the copper cations order into a kagome-like lattice of triangular clusters. The magnetism has been measured from 2 to 800 K and is highly influenced by the geometric arrangement of the Cu-II cations. An antiferromagnetic transition occurs at 5 K, but the sample does not reach a purely paramagnetic state until 460 K. C1 Northwestern Univ, Dept Chem, Evanston, IL 60208 USA. Northwestern Univ, Dept Mat Sci, Evanston, IL 60208 USA. Northwestern Univ, Sci & Technol Ctr Superconduct, Evanston, IL 60208 USA. Kyoto Univ, Inst Chem Res, Uji, Kyoto, Japan. Argonne Natl Lab, Argonne, IL 60439 USA. RP Poeppelmeier, KR (reprint author), Northwestern Univ, Dept Chem, 2145 Sheridan Rd, Evanston, IL 60208 USA. RI Dravid, Vinayak/B-6688-2009; Azuma, Masaki/C-2945-2009 OI Azuma, Masaki/0000-0002-8378-321X NR 24 TC 31 Z9 31 U1 0 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD MAY 26 PY 1999 VL 121 IS 20 BP 4787 EP 4792 DI 10.1021/ja984436e PG 6 WC Chemistry, Multidisciplinary SC Chemistry GA 202HJ UT WOS:000080646000007 ER PT J AU Bergmann, U Glatzel, P deGroot, F Cramer, SP AF Bergmann, U Glatzel, P deGroot, F Cramer, SP TI High resolution K capture X-ray fluorescence spectroscopy: A new tool for chemical characterization SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID ABSORPTION C1 Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Appl Sci, Davis, CA 95616 USA. Univ Utrecht, Dept Chem, NL-3584 CA Utrecht, Netherlands. RP Cramer, SP (reprint author), Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA. RI Glatzel, Pieter/E-9958-2010; de Groot, Frank/A-1918-2009 OI Glatzel, Pieter/0000-0001-6532-8144; NR 21 TC 19 Z9 21 U1 2 U2 14 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD MAY 26 PY 1999 VL 121 IS 20 BP 4926 EP 4927 DI 10.1021/ja984454w PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 202HJ UT WOS:000080646000036 ER PT J AU Goldberg, LA Matias, Y Rao, S AF Goldberg, LA Matias, Y Rao, S TI An optical simulation of shared memory SO SIAM JOURNAL ON COMPUTING LA English DT Article DE PRAM; PRAM simulation; optical networks ID PARALLEL COMPUTERS; COMMUNICATION; ALGORITHMS; PRAMS AB We present a work-optimal randomized algorithm for simulating a shared memory machine (pram) on an optical communication parallel computer (OCPC). The OCPC model is motivated by the potential of optical communication for parallel computation. The memory of an OCPC is divided into modules, one module per processor. Each memory module only services a request on a timestep if it receives exactly one memory request. Our algorithm simulates each step of an n lg lg n-processor EREW pram on an n-processor OCPC in O(lg lg n) expected delay. (The probability that the delay is longer than this is at most n(-alpha) for any constant alpha.) The best previous simulation, due to Valiant, required Theta(lg n) expected delay. C1 Univ Warwick, Dept Comp Sci, Coventry CV4 7AL, W Midlands, England. Sandia Natl Labs, Livermore, CA 94550 USA. AT&T Bell Labs, Murray Hill, NJ 07974 USA. NEC Res Inst, Princeton, NJ 08540 USA. RP Univ Warwick, Dept Comp Sci, Coventry CV4 7AL, W Midlands, England. EM leslie@dcs.warwick.ac.uk; matias@research.att.com; satish@research.nec.com NR 39 TC 6 Z9 6 U1 0 U2 0 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 0097-5397 EI 1095-7111 J9 SIAM J COMPUT JI SIAM J. Comput. PD MAY 26 PY 1999 VL 28 IS 5 BP 1829 EP 1847 DI 10.1137/S0097539795290507 PG 19 WC Computer Science, Theory & Methods; Mathematics, Applied SC Computer Science; Mathematics GA 203LY UT WOS:000080710200013 ER PT J AU Helgesson, J Randrup, J AF Helgesson, J Randrup, J TI Spin-isospin modes in heavy-ion collisions II. Transport simulations SO ANNALS OF PHYSICS LA English DT Article ID PION DISPERSION-RELATION; DILEPTON PRODUCTION; ELASTIC-SCATTERING; HOLE MODEL; ENERGY; MATTER AB Transport simulations including in-medium properties derived in a microscopic pi+NN-1 + Delta N-1 model in infinite nuclear matter are presented. In-medium pion dispersion relations, partial Delta decay widths, pion absorption cross sections, and Delta cross sections are incorporated into the transport description by means of a local density approximation. Comparisons between standard and medium-modified transport simulations are presented. Large changes of pi and Delta production and absorption rates are found, but the effect on the resulting pion observables is relatively small. (C) 1999 Academic Press. C1 ECT, European Ctr Studies Theoret Nucl Phys & Related, Trento, Italy. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Helgesson, J (reprint author), Malmo Univ, SE-20506 Malmo, Sweden. EM johan.helgesson@te.mah.se NR 38 TC 1 Z9 1 U1 0 U2 0 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0003-4916 J9 ANN PHYS-NEW YORK JI Ann. Phys. PD MAY 25 PY 1999 VL 274 IS 1 BP 1 EP 44 DI 10.1006/aphy.1999.5906 PG 44 WC Physics, Multidisciplinary SC Physics GA 202VP UT WOS:000080673100001 ER PT J AU Gallagher, SC Callaghan, AJ Zhao, JK Dalton, H Trewhella, J AF Gallagher, SC Callaghan, AJ Zhao, JK Dalton, H Trewhella, J TI Global conformational changes control the reactivity of methane monooxygenase SO BIOCHEMISTRY LA English DT Article ID METHYLOCOCCUS-CAPSULATUS-BATH; METHYLOSINUS-TRICHOSPORIUM OB3B; SMALL-ANGLE SCATTERING; REGULATORY PROTEIN-B; LIGHT-CHAIN KINASE; COMPONENT-B; HYDROXYLASE COMPONENT; NEUTRON-SCATTERING; SUBSTRATE-BINDING; X-RAY AB We present here X-ray scattering data that yield new structural information on the multicomponent enzyme methane monooxygenase and its components: a hydroxylase dimer, and two copies each of a reductase and regulatory protein B. Upon formation of the enzyme complex, the hydroxylase undergoes a dramatic conformational change that is observed in the scattering data as a fundamental change in shape of the scattering particle such that one dimension is narrowed (by 25% or 24 Angstrom) while the longest dimension increases (by 20% or 25 Angstrom). These changes also are reflected in a 13% increase in radius of gyration upon complex formation. Both the reductase and protein B are required for inducing the conformational change. We have modeled the scattering data for the complex by systematically modifying the crystal structure of the hydroxylase and using ellipsoids to represent the reductase and protein B components. Our model indicates that protein B plays a role in optimizing the interaction between the active centers of the reductase and hydroxylase components, thus, facilitating electron transfer between them. In addition, the model suggests reasons why the hydroxylase exists as a dimer and that a possible role for the outlying gamma-subunit may be to stabilize the complex through its interaction with the other components. We further show that proteolysis of protein B to form the inactive B' results in a conformational change and B' does not bind to the hydroxylase. The truncation thus could represent a regulatory mechanism for controlling the enzyme activity. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87544 USA. Univ Warwick, Coventry CV4 7AL, W Midlands, England. RP Trewhella, J (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Mail Stop G758, Los Alamos, NM 87544 USA. RI Zhao, Jinkui/B-7872-2013; OI Zhao, Jinkui/0000-0002-7756-1952; Trewhella, Jill/0000-0002-8555-6766 NR 37 TC 35 Z9 35 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD MAY 25 PY 1999 VL 38 IS 21 BP 6752 EP 6760 DI 10.1021/bi982991n PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 201KL UT WOS:000080593900005 PM 10346895 ER PT J AU Hernandez, G Blumenthal, DK Kennedy, MA Unkefer, CJ Trewhella, J AF Hernandez, G Blumenthal, DK Kennedy, MA Unkefer, CJ Trewhella, J TI Troponin I inhibitory peptide (96-115) has an extended conformation when bound to skeletal muscle troponin C SO BIOCHEMISTRY LA English DT Article ID NUCLEAR-MAGNETIC-RESONANCE; ANGLE X-RAY; NMR-SPECTROSCOPY; SECONDARY STRUCTURE; NEUTRON-SCATTERING; MATRIX ANALYSIS; COMPLEX; BINDING; CALCIUM; CALMODULIN AB We have utilized CD and NMR spectroscopy to study the conformation of the troponin I (TnI) inhibitory peptide [TnI(96-115)] free in solution and when bound to troponin C (TnC). Analysis of the CD spectrum of the free peptide in aqueous solution indicates it is only similar to 3% helix. Upon complex formation with TnC, there is no change in total helix content compared to the sum of the free components. The NMR data support a predominantly extended conformation for the free peptide. TnI(96-115) bound to TnC was selectively observed by NMR using deuterated TnC (dTnC). For the 1:1 ratio of TnI(96-115) to dTnC used, 95% of the peptide was bound to dTnC. The chemical shifts of the TnC-bound peptide resonances are similar to those of the free peptide, indicating that the change in peptide conformation as a consequence of binding to TnC is small. For the TnC-bound TnI(96-115) peptide, the ratios of sequential H-alpha-H-N to intraresidue H-N-H-alpha NOE cross-peak volumes support a predominantly extended conformation, possibly kinked at Gly(104). The results presented here are in agreement with sequence analysis predictions for TnI(96-115) as a free peptide or within the intact TnI sequence. The predominantly extended structure for the 96-115 inhibitory sequence segment of TnI with a kink at Gly(104) may facilitate its binding alternately to actin or TnC in response to the Ca2+ signals that control thick and thin filament interactions during the contractile cycle. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Univ Utah, Dept Pharmacol & Toxicol, Salt Lake City, UT 84112 USA. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Trewhella, J (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Mail Stop G758, Los Alamos, NM 87545 USA. OI Trewhella, Jill/0000-0002-8555-6766; Blumenthal, Donald/0000-0002-8614-1167 FU NCI NIH HHS [5 P30 CA42014]; NCRR NIH HHS [RR 02231]; NIGMS NIH HHS [GM40528] NR 36 TC 19 Z9 19 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD MAY 25 PY 1999 VL 38 IS 21 BP 6911 EP 6917 DI 10.1021/bi990150q PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 201KL UT WOS:000080593900023 PM 10346913 ER PT J AU Herman, GS Kim, YJ Chambers, SA Peden, CHF AF Herman, GS Kim, YJ Chambers, SA Peden, CHF TI Interaction of D2O with CeO2(001) investigated by temperature-programmed desorption and X-ray photoelectron spectroscopy SO LANGMUIR LA English DT Article ID SINGLE-CRYSTAL; CEO2 SURFACES; WATER; OXYGEN; CERIUM; H2O; CHEMISORPTION; FILMS; ADSORPTION; REDUCTION AB The interaction of D2O with the CeO2(001) surface was studied with temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS). It was found with TPD that D2O desorption occurs in three states with temperatures of 152, 200, and 275 K, which are defined as multilayer D2O, weakly bound surface D2O, and hydroxyl recombination, respectively. O Is XPS measurements for high D2O exposures, where multilayer water desorption was observed in the TPD, resulted in emission from only the substrate and surface hydroxyls. This is likely due to a nonwetting behavior of D2O on this surface with the formation of nanosized clusters. An analysis of the Ols XPS data indicates that the surface has a hydroxyl coverage of 0.9 monolayers for large water exposures at 85 K. This is consistent with a model in which the polar CeO2(001) surface can be stabilized by a reduction of the dipole in the top layer by the formation of a full monolayer of hydroxyls. C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Taejon Natl Univ Technol, Dept Chem Technol, Taejon, South Korea. RP Herman, GS (reprint author), Pacific NW Lab, Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. OI Peden, Charles/0000-0001-6754-9928 NR 31 TC 24 Z9 24 U1 0 U2 14 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD MAY 25 PY 1999 VL 15 IS 11 BP 3993 EP 3997 DI 10.1021/la990094u PG 5 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 201RY UT WOS:000080610400043 ER PT J AU Dawson, SP Keizer, J Pearson, JE AF Dawson, SP Keizer, J Pearson, JE TI Fire-diffuse-fire model of dynamics of intracellular calcium waves SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID INOSITOL TRISPHOSPHATE; CARDIAC MYOCYTES; ELEMENTARY EVENTS; XENOPUS OOCYTES; LAEVIS OOCYTES; CA2+ WAVES; OSCILLATIONS; SPARKS; 1,4,5-TRISPHOSPHATE; MICRODOMAINS AB When Ca2+ is released from internal stores in living cells, the resulting wave of increased concentration can travel without deformation (continuous propagation) or with burst-like behavior (saltatory propagation). We analyze the "fire-diffuse-fire'' model in order to illuminate the differences between these two modes of propagation. We show that the Ca2+ release wave in immature Xenopus oocytes and cardiac myocytes is saltatory, whereas the fertilization wave in the mature oocyte is continuous. C1 Univ Calif Davis, Inst Theoret Dynam & Neurobiol Physiol & Behav, Davis, CA 95616 USA. Univ Calif Los Alamos Natl Lab, Div Appl Theoret Phys, Los Alamos, NM 87545 USA. Univ Buenos Aires, Fac Ciencias Exactas & Nat, Dept Fis, RA-1428 Buenos Aires, DF, Argentina. RP Pearson, JE (reprint author), Univ Calif Davis, Inst Theoret Dynam & Neurobiol Physiol & Behav, Davis, CA 95616 USA. OI Ponce Dawson, Silvina/0000-0001-6550-4267 FU NCRR NIH HHS [R01 RR10081] NR 28 TC 95 Z9 97 U1 0 U2 3 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD MAY 25 PY 1999 VL 96 IS 11 BP 6060 EP 6063 DI 10.1073/pnas.96.11.6060 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 200ER UT WOS:000080527100030 PM 10339541 ER PT J AU Lee, YE Norton, DP Budai, JD AF Lee, YE Norton, DP Budai, JD TI Enhanced photoluminescence in epitaxial ZnGa2O4 : Mn thin-film phosphors using pulsed-laser deposition SO APPLIED PHYSICS LETTERS LA English DT Article ID ELECTROLUMINESCENT DEVICES AB The growth and properties of ZnGa2O4:Mn thin-film phosphors on single crystal substrates using pulsed-laser deposition were investigated. Epitaxial film properties were compared to polycrystalline films deposited on glass substrates. Green photoluminescence was observed for as-deposited films with no postannealing required. Enhanced luminescent intensity in the epitaxial films was observed as compared to randomly oriented polycrystalline films, suggesting that grain boundaries and grain alignment strongly influence the luminescent properties. The ratio of Zn/Ga in the films also affected photoluminescence properties, with strong green emission observed in Zn-deficient films. (C) 1999 American Institute of Physics. [S0003-6951(99)05121-9]. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Lee, YE (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. RI Budai, John/R-9276-2016 OI Budai, John/0000-0002-7444-1306 NR 7 TC 65 Z9 66 U1 3 U2 19 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 24 PY 1999 VL 74 IS 21 BP 3155 EP 3157 DI 10.1063/1.124095 PG 3 WC Physics, Applied SC Physics GA 199EM UT WOS:000080467500026 ER PT J AU Wilcoxon, JP Samara, GA AF Wilcoxon, JP Samara, GA TI Tailorable, visible light emission from silicon nanocrystals SO APPLIED PHYSICS LETTERS LA English DT Article ID SI AB Crystalline, size-selected Si nanocrystals in the size range 1.8-10 nm grown in inverse micellar cages exhibit highly structured optical absorption and photoluminescence (PL) across the visible range of the spectrum. The most intense PL for the smallest nanocrystals produced (similar to 2 nm) was in the blue (similar to 365 nm) with a radiative lifetime of similar to 1 ns and is attributed to direct recombination at zone center. (C) 1999 American Institute of Physics. [S0003-6951(99)01321-2]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Wilcoxon, JP (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. EM gasamar@sandia.gov NR 11 TC 131 Z9 133 U1 2 U2 18 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0003-6951 EI 1077-3118 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 24 PY 1999 VL 74 IS 21 BP 3164 EP 3166 DI 10.1063/1.124096 PG 3 WC Physics, Applied SC Physics GA 199EM UT WOS:000080467500029 ER PT J AU de Boer, J AF de Boer, J TI Six-dimensional supergravity on S-3 x AdS(3) and 2d conformal field theory SO NUCLEAR PHYSICS B LA English DT Review ID CALABI-YAU THREEFOLDS; SPINNING BLACK-HOLES; SUPERCONFORMAL ALGEBRAS; D-BRANES; UNITARY REPRESENTATIONS; ELLIPTIC GENERA; F-THEORY; 11-DIMENSIONAL SUPERGRAVITY; CYCLIC PERMUTATIONS; QUANTUM-GRAVITY AB In this paper we study the relation between six-dimensional supergravity compactified on S-3 X AdS(3) and certain two-dimensional conformal field theories. We compute the Kaluza-Klein spectrum of supergravity using representation theory; these methods are quite general and can also be applied to other compactifications involving anti-de Sitter spaces. A detailed comparison between the spectrum of the two-dimensional conformal field theory and supergravity is made, and we find complete agreement. This applies even at the level of certain non-chiral primaries, and we propose a resolution to the puzzle of the missing states recently raised by Vafa. As a further illustration of the method the Kaluza-Klein spectra of F-theory on M-6 X S-3 X AdS(3) and of M-theory on M-6 X S-2 X AdS(3) are computed, with M-6 some Calabi-Yau manifold. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RP de Boer, J (reprint author), Univ Calif Berkeley, Dept Phys, 366 Le Conte Hall, Berkeley, CA 94720 USA. NR 139 TC 160 Z9 160 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD MAY 24 PY 1999 VL 548 IS 1-3 BP 139 EP 166 DI 10.1016/S0550-3213(99)00160-1 PG 28 WC Physics, Particles & Fields SC Physics GA 205VY UT WOS:000080842300004 ER PT J AU Burles, S Nollett, KM Truran, JW Turner, MS AF Burles, S Nollett, KM Truran, JW Turner, MS TI Sharpening the predictions of big-bang nucleosynthesis SO PHYSICAL REVIEW LETTERS LA English DT Article ID PRIMORDIAL ABUNDANCE; HELIUM ABUNDANCE; CROSS-SECTION; LOW ENERGIES; H-2((P)OVER-RIGHT-ARROW,GAMMA)HE-3; HE-3(ALPHA,GAMMA)BE-7 AB We have reexamined the nuclear inputs to big-bang nucleosynthesis using Monte Carlo realization of the cross-section data to directly estimate theoretical uncertainties for the yields of D, He-3, and Li-7. Our results indicate that previous estimates of the uncertainties were too large by a factor of 2. Using the Burles-Tytler deuterium measurement, we infer a baryon density Omega(B)/h(2) = 0.019 +/- 0.0024, predict a primeval He-4 mass fraction Yr = 0.246 +/- 0.0014, and obtain a limit to the equivalent number of neutrino species N-v < 3.20 (all at 95% C.L.). We also identify key reactions and the energies, where improved data would allow further progress. [S0031-9007(99)09188-7]. C1 Univ Chicago, Enrico Fermi Inst, Dept Astron & Astrophys, Chicago, IL 60637 USA. Univ Chicago, Dept Phys, Chicago, IL 60637 USA. NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Burles, S (reprint author), Univ Chicago, Enrico Fermi Inst, Dept Astron & Astrophys, Chicago, IL 60637 USA. OI Nollett, Kenneth/0000-0002-0671-320X NR 26 TC 193 Z9 194 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 24 PY 1999 VL 82 IS 21 BP 4176 EP 4179 DI 10.1103/PhysRevLett.82.4176 PG 4 WC Physics, Multidisciplinary SC Physics GA 198CX UT WOS:000080405500006 ER PT J AU Edwards, RG Heller, UM Kiskis, J Narayanan, R AF Edwards, RG Heller, UM Kiskis, J Narayanan, R TI Quark spectra, topology, and random matrix theory SO PHYSICAL REVIEW LETTERS LA English DT Article ID VOLUME PARTITION-FUNCTIONS; LATTICE DIRAC OPERATOR; MICROSCOPIC UNIVERSALITY; GAUGE-THEORIES; QCD; SU(2); EDGE AB Quark spectra in QCD are linked to fundamental properties of the theory including the identification of pions as the Goldstone bosons of spontaneously broken chiral symmetry. The lattice overlap Dirac operator provides a nonperturbative, ultraviolet-regularized description of quarks with the correct chiral symmetry. Properties of the spectrum of this operator and their relation to random matrix theory are studied here. In particular, the predictions from chiral random matrix theory in topologically nontrivial gauge field sectors are tested for the first time. [S0031-9007(99)09176-0]. C1 Florida State Univ, Supercomp Computat Res Inst, Tallahassee, FL 32306 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Edwards, RG (reprint author), Florida State Univ, Supercomp Computat Res Inst, Tallahassee, FL 32306 USA. OI Heller, Urs M./0000-0002-2780-5584 NR 34 TC 86 Z9 86 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 24 PY 1999 VL 82 IS 21 BP 4188 EP 4191 DI 10.1103/PhysRevLett.82.4188 PG 4 WC Physics, Multidisciplinary SC Physics GA 198CX UT WOS:000080405500009 ER PT J AU Dziarmaga, J Sadzikowski, M AF Dziarmaga, J Sadzikowski, M TI Antibaryon density in the central rapidity region of heavy-ion collisions SO PHYSICAL REVIEW LETTERS LA English DT Article ID NUCLEUS-NUCLEUS COLLISIONS; CHIRAL PHASE-TRANSITION; BARYON PRODUCTION; TOPOLOGICAL MODEL; QCD AB We consider (anti-) baryon production in relativistic heavy-ion collisions as a production of topological defects during the chiral phase transition. Nonzero light quark masses, which explicitly break chiral symmetry, suppress the (anti-) baryon density. Hardly any (anti-) baryons will be produced in the central rapidity region of a heavy-ion collision. The antibaryon suppression may serve as a signal of quark-gluon plasma production. [S0031-9007(99)09259-5]. C1 Jagiellonian Univ, Inst Phys, PL-30059 Krakow, Poland. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Inst Nucl Phys, PL-31342 Krakow, Poland. RP Jagiellonian Univ, Inst Phys, Reymonta 4, PL-30059 Krakow, Poland. NR 23 TC 7 Z9 7 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 24 PY 1999 VL 82 IS 21 BP 4192 EP 4195 DI 10.1103/PhysRevLett.82.4192 PG 4 WC Physics, Multidisciplinary SC Physics GA 198CX UT WOS:000080405500010 ER PT J AU Wang, XD Zhang, XG AF Wang, XD Zhang, XG TI Low-temperature resistivity in a nearly half-metallic ferromagnet SO PHYSICAL REVIEW LETTERS LA English DT Article ID MAGNETORESISTANCE; LA1-XCAXMNO3; FILMS AB In a nearly half-metallic ferromagnet, such as a material exhibiting "colossal" magnetoresistance, the minority spin electrons close to the band edge at the Fermi energy are Anderson localized due to disorder; thus only majority electrons conduct current. This presents a unique electronic structure for which the linear response Boltzmann equation involving the scattering of a single magnon is exactly solvable. The solution yields a temperature dependent resistivity that scales as T-2.5 above approximately 60 K and contains a T-1.5 contribution below this temperature, and has a dependence on the magnetic field consistent with experiments. [S0031-9007(99)09140-1]. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Computat Phys & Engn Div, Oak Ridge, TN 37831 USA. RP Wang, XD (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. NR 10 TC 29 Z9 33 U1 2 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 24 PY 1999 VL 82 IS 21 BP 4276 EP 4279 DI 10.1103/PhysRevLett.82.4276 PG 4 WC Physics, Multidisciplinary SC Physics GA 198CX UT WOS:000080405500031 ER PT J AU Janko, B Kosztin, I Levin, K Norman, MR Scalapino, DJ AF Janko, B Kosztin, I Levin, K Norman, MR Scalapino, DJ TI Incoherent pair tunneling as a probe of the cuprate pseudogap SO PHYSICAL REVIEW LETTERS LA English DT Article ID T-C SUPERCONDUCTORS; NORMAL-STATE; BI2SR2CACU2O8+DELTA; CONDUCTIVITY; GAP; SCATTERING; DEPENDENCE AB We argue that incoherent pair tunneling in a cuprate superconductor junction with an optimally doped superconducting and an underdoped normal lead can be used to detect the presence of pairing correlations in the pseudogap phase of the underdoped lead. We estimate that the junction characteristics most suitable for studying the pair tunneling current are close to recently manufactured cuprate tunneling devices. [S0031-9007(99)09210-8]. C1 Univ Chicago, James Franck Inst, Chicago, IL 60637 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. RP Janko, B (reprint author), Univ Chicago, James Franck Inst, 5640 S Ellis Ave, Chicago, IL 60637 USA. RI Norman, Michael/C-3644-2013 NR 31 TC 18 Z9 18 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 24 PY 1999 VL 82 IS 21 BP 4304 EP 4307 DI 10.1103/PhysRevLett.82.4304 PG 4 WC Physics, Multidisciplinary SC Physics GA 198CX UT WOS:000080405500038 ER PT J AU Yan, YF Pennycook, SJ Tsai, AP AF Yan, YF Pennycook, SJ Tsai, AP TI Comment on "Direct imaging of local chemical disorder and columnar vacancies in ideal decagonal Al-Ni-Co quasicrystals" - Yan, Pennycook, and Pang reply SO PHYSICAL REVIEW LETTERS LA English DT Article C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Natl Res Inst Met, Tsukuba, Ibaraki 305, Japan. RP Yan, YF (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. NR 5 TC 1 Z9 1 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 24 PY 1999 VL 82 IS 21 BP 4367 EP 4367 DI 10.1103/PhysRevLett.82.4367 PG 1 WC Physics, Multidisciplinary SC Physics GA 198CX UT WOS:000080405500056 ER PT J AU Grimsditch, M AF Grimsditch, M TI Comment on "Evidence of quantum correlation effects of protons and deuterons in Raman spectra of liquid H2O-D2O" SO PHYSICAL REVIEW LETTERS LA English DT Article C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Grimsditch, M (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 3 TC 3 Z9 3 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 24 PY 1999 VL 82 IS 21 BP 4368 EP 4368 DI 10.1103/PhysRevLett.82.4368 PG 1 WC Physics, Multidisciplinary SC Physics GA 198CX UT WOS:000080405500057 ER PT J AU Stewart, FF Harrup, MK AF Stewart, FF Harrup, MK TI Phosphazene monomers from the regiospecific reaction of tert-butylhydroquinone with hexachlorocyclotriphosphazene: A new composite material precursor SO JOURNAL OF APPLIED POLYMER SCIENCE LA English DT Article DE composites; polymers; phosphazenes; synthesis; cyclomatrix ID POLYMER MEMBRANES; FIRE-RESISTANT; POLYPHOSPHAZENE; ELECTROLYTES AB A new synthesis of a phosphazene-based polymer precursor is described. tert-Butylhydroquinone was found to react with hexachlorocyclotriphosphazene in the presence of a base, 4-picoline, in cyclohexane to yield a regiospecifically substituted hexa-tert-butylcyclotriphosphazene. This reaction proceeds more rapidly to completion and in a higher yield than data previously reported for analogous cyclotriphosphazenes. Nuclear magnetic resonance spectroscopy and thermal methods (differential scanning calorimetry and thermogravimetric analysis) were employed to characterize this material, and it is observed that the bifunctional tert-butylhydroquinone substitutes only at the least hindered phenolic hydroxyl under the reported reaction conditions. This conclusion clarifies published data that suggests that without the tert-butyl substituent on the hydroquinone ring, crosslinking between phosphazene rings occurs to some extent. (C) 1999 John Wiley & Sons, Inc. C1 Lockheed Martin Idaho Technol Co, Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Stewart, FF (reprint author), Lockheed Martin Idaho Technol Co, Idaho Natl Engn & Environm Lab, POB 1625, Idaho Falls, ID 83415 USA. NR 22 TC 12 Z9 12 U1 2 U2 8 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0021-8995 J9 J APPL POLYM SCI JI J. Appl. Polym. Sci. PD MAY 23 PY 1999 VL 72 IS 8 BP 1085 EP 1090 DI 10.1002/(SICI)1097-4628(19990523)72:8<1085::AID-APP13>3.0.CO;2-R PG 6 WC Polymer Science SC Polymer Science GA 179GE UT WOS:000079317300013 ER PT J AU Guallar, V Batista, VS Miller, WH AF Guallar, V Batista, VS Miller, WH TI Semiclassical molecular dynamics simulations of excited state double-proton transfer in 7-azaindole dimers SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID INITIAL-VALUE REPRESENTATION; ELECTRON-TRANSFER REACTIONS; BARRIER HYDROGEN-BONDS; MODEL BASE-PAIRS; CHEMICAL-REACTIONS; ENZYME-REACTIONS; SUPERSONIC JET; ATOM TRANSFER; FLUORESCENCE; TRANSITION AB An ab initio excited state potential energy surface is constructed for describing excited state double proton transfer in the tautomerization reaction of photo-excited 7-azaindole dimers, and the ultrafast dynamics is simulated using the semiclassical (SC) initial value representation (IVR). The potential energy surface, determined in a reduced dimensionality, is obtained at the CIS level of quantum chemistry, and an approximate version of the SC-IVR approach is introduced which scales linearly with the number of degrees of freedom of the molecular system. The accuracy of this approximate SC-IVR approach is verified by comparing our semiclassical results with full quantum mechanical calculations. We find that proton transfer usually occurs during the first intermonomer symmetric-stretch vibration, about 100 fs after photoexcitation of the system, and produces an initial 15 percent population decay of the reactant base-pair, which is significantly reduced by isotopic substitution. (C) 1999 American Institute of Physics. [S0021-9606(99)01820-6]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Guallar, V (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. EM miller@neon.cchem.berkeley.edu RI Guallar, Victor/B-1579-2013 OI Guallar, Victor/0000-0002-4580-1114 NR 92 TC 125 Z9 126 U1 0 U2 14 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 22 PY 1999 VL 110 IS 20 BP 9922 EP 9936 DI 10.1063/1.478866 PG 15 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 197MC UT WOS:000080367700017 ER PT J AU Ochsenfeld, C Kaiser, RI Lee, YT Head-Gordon, M AF Ochsenfeld, C Kaiser, RI Lee, YT Head-Gordon, M TI Coupled-cluster ab initio investigation of singlet triplet CH2S isomers and the reaction of atomic carbon with hydrogen sulfide to HCS HSC SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID GAUSSIAN-BASIS SETS; COMET SHOEMAKER-LEVY-9; SYMMETRY-BREAKING; INTERSTELLAR C3H; WAVE-FUNCTIONS; MOLECULES; SPECTROSCOPY; CCSD(T); MODEL; H2CS AB The reaction of C(P-3) with H2S to HCS/HSC isomers is investigated with high level ab initio methods. Besides reaction energies to form HCS/HSC, the energetics and properties of different singlet/triplet H2CS reaction intermediates are studied. The combination of ab initio theory and crossed molecular beams experiments leads to the conclusion that mainly HCS is formed under single collision conditions and that the reaction is indirect and proceeds through a thiohydroxycarbene intermediate. (C) 1999 American Institute of Physics. [S0021-9606(99)31217-4]. C1 Univ Mainz, Inst Phys Chem, D-55099 Mainz, Germany. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Acad Sinica, Inst Atom & Mol Sci, Taipei 106, Taiwan. Tech Univ Chemnitz Zwickau, Inst Phys, D-09107 Chemnitz, Germany. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Ochsenfeld, C (reprint author), Univ Mainz, Inst Phys Chem, D-55099 Mainz, Germany. RI Lee, Yuan-Tseh/F-7914-2012; Ochsenfeld, Christian/E-8021-2015 OI Ochsenfeld, Christian/0000-0002-4189-6558 NR 35 TC 19 Z9 19 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 22 PY 1999 VL 110 IS 20 BP 9982 EP 9988 DI 10.1063/1.478871 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 197MC UT WOS:000080367700023 ER PT J AU Dang, LX AF Dang, LX TI Intermolecular interactions of liquid dichloromethane and equilibrium properties of liquid-vapor and liquid-liquid interfaces: A molecular dynamics study SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MONTE-CARLO SIMULATION; WATER INTERFACE; ELECTRON-TRANSFER; SURFACE-TENSION; POLARIZABILITY; POTENTIALS; MODEL AB Extensive molecular dynamics simulations are carried out to study the molecular interactions, liquid states, and liquid/vapor properties of dichloromethane. The study is also extended to the equilibrium properties of the liquid/liquid interface of water-dichloromethane. The intermolecular interactions among water, dichloromethane, and water-dichloromethane are described using our polarizable potential models. The equilibrium properties of liquid dichloromethane, including the radial distribution functions, the intermolecular structural factor, the self-diffusion coefficient, and the dielectric constant, are evaluated. The dielectric constant is computed using Ewald summation techniques and the computed result compared reasonably well with the available experimental data. Properties such as surface tensions and density profiles of liquid/vapor dichloromethane are evaluated. We found that the computed surface tensions for several temperatures are in excellent agreement with experimental data. The computed density profile of the liquid/liquid interface of water-dichloromethane is averaged over 1 ns and we found the computed profile to be quite smooth and stable. The effect of polarization on the liquid/liquid interfacial equilibrium properties is evaluated by computing the dipole moments of water and dichloromethane molecules as a function of the distance normal to the interface. We found that these values deviated significantly from the simulations that are based on nonpolarizable potential models. We attribute these observations to the changes in the electric fields around the water and dichloromethane molecules near the interface. (C) 1999 American Institute of Physics. [S0021-9606(99)70220-5]. C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Dang, LX (reprint author), Pacific NW Lab, Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. NR 38 TC 53 Z9 53 U1 1 U2 32 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 22 PY 1999 VL 110 IS 20 BP 10113 EP 10122 DI 10.1063/1.478884 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 197MC UT WOS:000080367700036 ER PT J AU Lessmann, A Schuster, M Riechert, H Brennan, S Munkholm, A Materlik, G AF Lessmann, A Schuster, M Riechert, H Brennan, S Munkholm, A Materlik, G TI Fluorescence x-ray standing wave study on (AlAs)(GaAs) superlattices SO JOURNAL OF PHYSICS D-APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 4th Biennial Conference on High Resolution X-ray Diffraction and Topography (XTOP 98) CY SEP 09-11, 1998 CL UNIV DURHAM, DURHAM, ENGLAND HO UNIV DURHAM ID DIFFRACTION AB X-ray standing waves (XSW) were used to investigate the structure of molecular beam epitaxy (MBE) grown (AlAs)(3)(GaAs)(7) short-period superlattices (SPSL). The modulation of the Al K, As L, and Ga L x-ray fluorescence induced by XSW was measured at the zero-order superlattice (SL) satellite (AlAs)(GaAs)(004,0) and the GaAs(004) substrate Bragg reflection. From the shape of the fluorescence yield modulations and the diffraction pattern, a model of the interfaces is derived by comparing the experimental data with dynamical calculations of the x-ray wave held distribution and reflectivity. A straightforward analysis of the fluorescence measurements at the SL satellite shows that in AlAs layers a high crystalline order is established, whereas in GaAs layers a fraction of the Ga and As atoms is not on ideal lattice sites, but is displaced towards the substrate. The data can be explained by a model in which, at each AlAs/GaAs interface of the GaAs layers, two Ga atom planes are displaced by 0.035 nm and 0.008 nm and one As atom plane by 0.023 nm. The displacements within the GaAs layers exhibit a mirror symmetry with respect to the centre of each layer. C1 SLAC, Stanford Synchrotron Radiat Lab, Menlo Park, CA 94025 USA. Rich Seifert & Co, Rontgenwerk, Branch Off Munich, D-80997 Munich, Germany. Siemens AG, Corp Technol, D-81739 Munich, Germany. DESY, Hamburger Synchrotronstrahlungslab Hasylab, D-22603 Hamburg, Germany. RP Lessmann, A (reprint author), Rich Seifert & Co, Rontgenwerk, Branch Off Munich, Mannertstr 36, D-80997 Munich, Germany. RI Riechert, Henning/G-4178-2016 NR 15 TC 5 Z9 5 U1 1 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0022-3727 J9 J PHYS D APPL PHYS JI J. Phys. D-Appl. Phys. PD MAY 21 PY 1999 VL 32 IS 10A SI SI BP A65 EP A70 DI 10.1088/0022-3727/32/10A/314 PG 6 WC Physics, Applied SC Physics GA 203VZ UT WOS:000080730000015 ER PT J AU Averett, TD Crabb, DG Day, DB Liu, TJ McCarthy, JS Mitchell, J Rondon, O Zimmermann, D Sick, I Zihlmann, B Court, G Dutz, H Meyer, W Rijllart, A St Lorant, S Button-Shafer, J Johnson, J AF Averett, TD Crabb, DG Day, DB Liu, TJ McCarthy, JS Mitchell, J Rondon, O Zimmermann, D Sick, I Zihlmann, B Court, G Dutz, H Meyer, W Rijllart, A St Lorant, S Button-Shafer, J Johnson, J TI A solid polarized target for high-luminosity experiments SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID PROTON POLARIZATION AB We have built a polarized proton and deuteron target for experiments using intense high-energy electron beams. This system exploits dynamical nuclear polarization of irradiated ammonia in a 5T magnetic field at temperatures near 1 K. We describe the various features and the performance of the target. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Virginia, Inst Nucl & Particle Phys, Dept Phys, Charlottesville, VA 22901 USA. Univ Basel, Dept Phys & Astron, Basel, Switzerland. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Univ Massachusetts, Dept Phys, Amherst, MA USA. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Univ Liverpool, Oliver Lodge Lab, Liverpool L69 3BX, Merseyside, England. Univ Bonn, Dept Phys, D-5300 Bonn, Germany. Ruhr Univ Bochum, Dept Phys, D-4630 Bochum, Germany. CERN, Geneva, Switzerland. RP Day, DB (reprint author), Univ Virginia, Inst Nucl & Particle Phys, Dept Phys, Charlottesville, VA 22901 USA. EM dbd@virginia.edu RI Rondon Aramayo, Oscar/B-5880-2013; Day, Donal/C-5020-2015 OI Day, Donal/0000-0001-7126-8934 NR 25 TC 19 Z9 19 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 EI 1872-9576 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1999 VL 427 IS 3 BP 440 EP 454 DI 10.1016/S0168-9002(98)01431-4 PG 15 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 200DH UT WOS:000080524000003 ER PT J AU Asratyan, A Balatz, M Boehnlein, D Childres, S Davidenko, G Dolgolenko, A Dzyubenko, G Kaftanov, V Kubantsev, M Reay, NW Musser, J Rosenfeld, C Stanton, NR Thun, R Tzanakos, GS Verebryusov, V Vishnyakov, V AF Asratyan, A Balatz, M Boehnlein, D Childres, S Davidenko, G Dolgolenko, A Dzyubenko, G Kaftanov, V Kubantsev, M Reay, NW Musser, J Rosenfeld, C Stanton, NR Thun, R Tzanakos, GS Verebryusov, V Vishnyakov, V TI Detecting the (quasi-) two-body decays of tau leptons in short-baseline neutrino oscillation experiments SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE neutrino oscillations; tau leptons; nuclear emulsion ID NU(MU)->NU(TAU) OSCILLATION; SEARCH AB Novel detector schemes are proposed for the short-baseline neutrino experiments of next generation, aimed at exploring the large-Delta m(2) domain of nu(mu)-nu(tau) oscillations in the appearance mode. These schemes emphasize good spectrometry for charged particles and for electromagnetic showers and efficient reconstruction of pi(0) --> gamma gamma decays. The basic elements are a sequence of relatively thin emulsion targets, immersed in magnetic field and interspersed with electronic trackers, and a fine-grained electromagnetic calorimeter built of lead glass. These elements act as an integral whole in reconstructing the electromagnetic showers. This conceptual scheme shows good performance in identifying the tau (quasi-) two-body decays by their characteristic kinematics and in selecting the electronic decays of the tau. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Inst Theoret & Expt Phys, Moscow 117259, Russia. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Kansas State Univ, Manhattan, KS 66506 USA. Indiana Univ, Bloomington, IN 47405 USA. Univ S Carolina, Columbia, SC 29208 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Univ Athens, Athens 15771, Greece. RP Asratyan, A (reprint author), Inst Theoret & Expt Phys, Moscow 117259, Russia. NR 19 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1999 VL 427 IS 3 BP 495 EP 509 DI 10.1016/S0168-9002(99)00038-8 PG 15 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 200DH UT WOS:000080524000007 ER PT J AU Tomasi, D Macchiavelli, AO AF Tomasi, D Macchiavelli, AO TI PCLOOK32: an interactive program for the analysis of spectra SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE interactive program; PC systems; PCLOOK32; graphical interface AB In this work we present an interactive program for the analysis of one-dimensional spectra developed to work on a personal computer (PC) platform. This 32-bit program named PCLOOK32, runs as a Windows95/NT1 application with a graphical user interface that allows the access to different functions via mouse operations. Although tailored to basic or applied nuclear physics work, it can be easily adapted to other applications. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Sao Paulo, Inst Fis, Sao Carlos, SP, Brazil. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Tomasi, D (reprint author), Univ Nacl San Martin, Escuela Ciencia & Tecnol, Alem 3901, RA-1651 San Andres, Argentina. RI Sao Carlos Institute of Physics, IFSC/USP/M-2664-2016 NR 4 TC 0 Z9 0 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1999 VL 427 IS 3 BP 583 EP 586 DI 10.1016/S0168-9002(98)01375-8 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 200DH UT WOS:000080524000015 ER PT J AU Byrd, JM AF Byrd, JM TI Maximizing integrated brightness in Touschek-dominated synchrotron light sources SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB We present a numerical study to maximize the integrated performance of third generation synchrotron radiation sources for cases where the beam lifetime is dominated by large-angle intrabeam (Touschek) scattering. The performance is characterized in two areas of user interest: high brightness and total flux. We study the effect on the time integral of these quantities through varying parameters such as the lifetime, vertical beam emittance, time between fills, filling time, and total beam current. The effect on topoff mode of operation in also discussed. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Byrd, JM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 2 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1999 VL 427 IS 3 BP 614 EP 621 DI 10.1016/S0168-9002(98)01370-9 PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 200DH UT WOS:000080524000018 ER PT J AU Cagliardi, CA Hawker, EA Tribble, RE Koetke, DD Nord, PM McGaughey, PL Brown, CN AF Cagliardi, CA Hawker, EA Tribble, RE Koetke, DD Nord, PM McGaughey, PL Brown, CN TI Hardware trigger system for Fermilab E866 (vol 418, pg 322, 1998) SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Correction C1 Texas A&M Univ, Inst Cyclotron, College Stn, TX 77843 USA. Valparaiso Univ, Dept Phys, Valparaiso, IN 46383 USA. Los Alamos Natl Lab, Div Phys, Los Alamos, NM 87545 USA. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. RP Cagliardi, CA (reprint author), Texas A&M Univ, Inst Cyclotron, College Stn, TX 77843 USA. EM cggroup@comp.tamu.edu NR 1 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 1999 VL 427 IS 3 BP 622 EP 622 DI 10.1016/S0168-9002(99)00034-0 PG 1 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 200DH UT WOS:000080524000019 ER PT J AU Dai, PC Mook, HA Hayden, SM Aeppli, G Perring, TG Hunt, RD Dogan, F AF Dai, PC Mook, HA Hayden, SM Aeppli, G Perring, TG Hunt, RD Dogan, F TI The magnetic excitation spectrum and thermodynamics of high-T-c superconductors SO SCIENCE LA English DT Article ID ELECTRONIC SPECIFIC-HEAT; NEUTRON-SCATTERING; YBA2CU3O6+X; FLUCTUATIONS; RESISTIVITY; ENERGY; 300-K AB Inelastic neutron scattering was used to study the wave vector- and frequency-dependent magnetic fluctuations in single crystals of superconducting YBa2Cu3O6+x. The spectra contain several important features, including a gap in the superconducting state, a pseudogap in the normal state, and the much-discussed resonance peak. The appearance of the pseudogap determined from transport and nuclear resonance coincides with formation of the resonance in the magnetic excitations. The exchange energy associated with the resonance has the temperature and doping dependences as well as the magnitude to describe approximately the electronic specific heat near the superconducting transition temperature (T-c). C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ Bristol, HH Wills Phys Lab, Bristol BS8 1TL, Avon, England. NEC Res Inst, Princeton, NJ 08540 USA. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. Univ Washington, Dept Mat Sci & Engn, Seattle, WA 98195 USA. RP Dai, PC (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. RI Hayden, Stephen/F-4162-2011; Dai, Pengcheng /C-9171-2012 OI Hayden, Stephen/0000-0002-3209-027X; Dai, Pengcheng /0000-0002-6088-3170 NR 23 TC 211 Z9 213 U1 2 U2 9 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAY 21 PY 1999 VL 284 IS 5418 BP 1344 EP 1347 DI 10.1126/science.284.5418.1344 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 198NN UT WOS:000080430600049 ER PT J AU Rawers, J Lillo, T AF Rawers, J Lillo, T TI Production of carbide and nitride free Fe-0.78C-0.79N SO SCRIPTA MATERIALIA LA English DT Article DE ferrite; austenite; iron-carbon-nitrogen; microstructure ID FE; BEHAVIOR; ALLOYS C1 US Bur Mines, Albany Res Ctr, Albany, OR 97321 USA. Natl Environm & Engn Lab, Idaho Falls, ID 83415 USA. RP Rawers, J (reprint author), US Bur Mines, Albany Res Ctr, Albany, OR 97321 USA. RI Lilllo, Thomas/S-5031-2016 OI Lilllo, Thomas/0000-0002-7572-7883 NR 9 TC 3 Z9 5 U1 0 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6462 J9 SCRIPTA MATER JI Scr. Mater. PD MAY 21 PY 1999 VL 40 IS 12 BP 1321 EP 1326 DI 10.1016/S1359-6462(99)00022-6 PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 213JZ UT WOS:000081270300001 ER PT J AU Benzi, M Szyld, DB Van Duin, A AF Benzi, M Szyld, DB Van Duin, A TI Orderings for incomplete factorization preconditioning of nonsymmetric problems SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article DE linear systems; nonsymmetric matrices; reorderings; permutation of sparse matrices; preconditioned iterative methods; incomplete factorizations; Krylov subspace methods ID CONJUGATE-GRADIENT METHODS; MINIMAL RESIDUAL ALGORITHM; NAVIER-STOKES EQUATIONS; LINEAR-SYSTEMS; ITERATIVE SOLUTION; LU FACTORIZATIONS; MATRIX; SIMULATION; COMPUTERS; GMRES AB Numerical experiments are presented whereby the effect of reorderings on the convergence of preconditioned Krylov subspace methods for the solution of nonsymmetric linear systems is shown. The preconditioners used in this study are different variants of incomplete factorizations. It is shown that certain reorderings for direct methods, such as reverse Cuthill-McKee, can be very beneficial. The benefit can be seen in the reduction of the number of iterations and also in measuring the deviation of the preconditioned operator from the identity. C1 Los Alamos Natl Lab, Sci Comp Grp CIC19, Los Alamos, NM 87545 USA. Temple Univ, Dept Math, Philadelphia, PA 19122 USA. Leiden Univ, Dept Comp Sci, NL-2300 RA Leiden, Netherlands. RP Benzi, M (reprint author), Los Alamos Natl Lab, Sci Comp Grp CIC19, MS B256, Los Alamos, NM 87545 USA. EM benzi@lanl.gov; szyld@math.temple.edu; arno@cs.leidenuniv.nl RI Szyld, Daniel/G-1388-2014 OI Szyld, Daniel/0000-0001-8010-0391 NR 50 TC 72 Z9 75 U1 0 U2 0 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 1064-8275 EI 1095-7197 J9 SIAM J SCI COMPUT JI SIAM J. Sci. Comput. PD MAY 21 PY 1999 VL 20 IS 5 BP 1652 EP 1670 DI 10.1137/S1064827597326845 PG 19 WC Mathematics, Applied SC Mathematics GA 199TD UT WOS:000080497600005 ER PT J AU Cheng, Q Fu, JA Burkard, R Wang, W Yamamoto, M Yang, J Stevens, RC AF Cheng, Q Fu, JA Burkard, R Wang, W Yamamoto, M Yang, J Stevens, RC TI Monolayer and epi-fluorescence microscopy studies of amino acid derivatized diacetylene lipids SO THIN SOLID FILMS LA English DT Article DE monolayers; diacetylene lipids; epi-fluorescence microscopy ID AIR-WATER-INTERFACE; POLYDIACETYLENE LIPOSOMES; COLORIMETRIC DETECTION; PHASE-DIAGRAM; FILMS; POLYMERIZATION; TRANSITIONS; MEMBRANES; BEHAVIOR; SHAPES AB Monolayers of amino acid derivatized diacetylene lipids on water were studied by Langmuir trough and epi-fluorescence microscopy (EFM). Examination of the amino acid derivatized diacetylene Lipids showed a wide variety of surface characteristics with many novel properties. Many of these new properties are advantageous for film-based biosensor development. To characterize this family of molecules, pressure-area ( pi-A) isotherms were measured that demonstrate hydrophilic headgroup compounds allow for close-packed monomolecular layer formation in the solid state upon continuous compression. The effect of subphase pH and temperature on monolayer compressibility and phase transition was examined. Decrease of pH results in attenuation of LE-LC phase transition in Gln-PDA monolayers due to charge screening, while temperature affects the monolayers through regular thermal agitation, and the effect is opposite to the thermal anomaly observed for the non-derivatized diacetylene lipids. EFM studies reveal that only the lipids derivatized with hydrophilic headgroups exhibit phase transition and domain formation, while those with hydrophobic headgroups do not easily form polymerizable matrices. The shape and growth of the domains were found to be strongly headgroup dependent. Photo-polymerization of diacetylene lipid domains on water using EFM is discussed. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Lawrence Berkeley Lab, Div Sci Mat, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Life Sci Div, Berkeley, CA 94720 USA. RP Stevens, RC (reprint author), Lawrence Berkeley Lab, Div Sci Mat, Berkeley, CA 94720 USA. RI Cheng, Jason/C-6345-2011 NR 24 TC 2 Z9 2 U1 0 U2 6 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD MAY 21 PY 1999 VL 345 IS 2 BP 292 EP 299 DI 10.1016/S0040-6090(98)01608-3 PG 8 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 206UD UT WOS:000080896900020 ER PT J AU Richman, BA Bisson, SE Trebino, R Sidick, E Jacobson, A AF Richman, BA Bisson, SE Trebino, R Sidick, E Jacobson, A TI All-prism achromatic phase matching for tunable second-harmonic generation SO APPLIED OPTICS LA English DT Article ID 2ND-HARMONIC GENERATION; FEMTOSECOND PULSES; DISPERSION; CONVERSION; GRISM; PAIR AB Achromatic phase matching (APM) involves dispersing the light entering a nonlinear optical crystal so that a wide range of wavelengths is simultaneously phase matched. We constructed an APM apparatus consisting of six prisms, the final dispersion angle of which was optimized to match to second order in wavelength the type I phase-matching angle of beta barium berate (BBO). With this apparatus, we doubled tunable fundamental light from 620 to 700 in in wavelength using a 4-mm-long BBO crystal. An analogous set of six prisms after the BBO crystal, optimized to second order in second-harmonic wavelength, realigned the output second-harmonic beams. Computer simulations predict that adjustment of a single prism can compensate annular misalignment of any or all the prisms before the crystal, and similarly for the prisms after the crystal. We demonstrated such compensation with the experimental device. The simulations also indicate that the phase-matching wavelength band can be shifted and optimized for different crystal lengths. (C) 1999 Optical Society of America. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. CVI Laser Corp, Livermore, CA 94550 USA. RP Richman, BA (reprint author), Sandia Natl Labs, Combust Res Facil, MS 9051, Livermore, CA 94551 USA. EM barichm@sandia.gov NR 13 TC 11 Z9 13 U1 0 U2 6 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD MAY 20 PY 1999 VL 38 IS 15 BP 3316 EP 3323 DI 10.1364/AO.38.003316 PG 8 WC Optics SC Optics GA 197BK UT WOS:000080344600028 PM 18319927 ER PT J AU Borozdin, K Revnivtsev, M Trudolyubov, S Shrader, C Titarchuk, L AF Borozdin, K Revnivtsev, M Trudolyubov, S Shrader, C Titarchuk, L TI Do the spectra of soft X-ray transients reveal bulk-motion inflow phenomenon? SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; black hole physics; radiation mechanisms : nonthermal; X-rays : stars ID ADVECTION-DOMINATED ACCRETION; HIGH-ENERGY OBSERVATIONS; BLACK-HOLE CANDIDATES; SPHERICAL ACCRETION; NEUTRON-STARS; GRO J1655-40; BINARIES; COMPTONIZATION; DISKS; NOVAE AB We present our analysis of the high-energy radiation from black hole (BH) transients using archival data obtained primarily with RXTE and a comprehensive test of the bulk-motion Comptonization (BMC) model for the high-soft state continuum. The emergent spectra of over 30 separate measurements of the GRO J1655-40, GRS 1915 + 105, GRS 1739-278, 4U 1630-47 XTE J1755-32, and EXO 1846-031 X-ray sources are successfully fitted by the BMC model, which has been derived from basic physical principles in previous work. This in turn provides direct physical insight into the innermost observable regions, where matter impinging on the event horizon can effectively be directly viewed. The BMC model is characterized by three parameters: the disk color temperature, a geometric factor related to the illumination of the BH site by the disk, and a spectral index related to the efficiency of the bulk-motion upscattering. For the case of GRO J1655-40, where there are distance and mass determinations, a self-consistency check of the BMC model has been made, in particular of the assumption regarding the dominance of gravitational forces over the pressure forces within the inner few Schwarzschild radii. We have also examined the time behavior of these parameters, which can provide information on the source structure. Using our inferred model parameters: color temperature, spectral index, and an absolute normalization, we present new, independently derived constraints on the BH mass, mass accretion rate, and the distance for the aforementioned sources. Also notable is the relationship between the color temperature and flux, which for CRO J1655-40 is entirely distinct from a simple T-4 dependence and strikingly consistent with the disk model we have invoked: a standard Shakura-Sunyaev disk with the modification to the electron scattering. This provides insight into the origin of the seed soft photons and allows us to impose an important estimation of the hardening parameter, T-h, which is the ratio of the color temperature to the effective temperature: we find T-h similar or equal to 12.6, higher than previous estimates used in the literature. C1 Univ Calif Los Alamos Natl Lab, NIS 2, Los Alamos, NM 87545 USA. Russian Acad Sci, Space Res Inst, High Energy Astrophys Dept, Moscow 117810, Russia. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Lanham, MD USA. George Mason Univ, Inst Computat Sci & Informat, Fairfax, VA 22030 USA. RP Borozdin, K (reprint author), Univ Calif Los Alamos Natl Lab, NIS 2, POB 1663, Los Alamos, NM 87545 USA. NR 60 TC 53 Z9 53 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 1999 VL 517 IS 1 BP 367 EP 380 DI 10.1086/307186 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 206RZ UT WOS:000080894200031 ER PT J AU Warner, TA Steinmaus, K Foote, H AF Warner, TA Steinmaus, K Foote, H TI An evaluation of spatial autocorrelation feature selection SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID BAND SELECTION; CLASSIFICATION; VARIOGRAMS; IMAGERY; AVIRIS; MODELS; SCALE AB Spatial autocorrelation analysis of ratioed image bands is compared to other methods of selecting features including the grouping of correlated bands, and the spacing of features equal wavelengths apart. In addition, features based on the band-passes of the SPOT XS, Multi-Spectral Scanner (MSS) and Thematic Mapper (TM) sensors are also synthesized. Three different types of spatial autocorrelation-based features are identified: (1) Narrow band features are selected by ranking the spatial autocorrelation of ratios of all possible combinations of bands. (2) Broad band features are produced by allowing the previously chosen best bands to merge with spectrally adjacent bands if this increases the overall spatial autocorrelation of the feature set. (3) Nonadjacent multiple band features are produced by removing the constraint that the merges are limited to neighbouring bands. The spatial autocorrelation ratio analysis suggests the majority of the most useful bands in an Airborne Visible/infrared Imaging Spectrometer (AVIRIS) scene of shrub-steppe vegetation are in the visible and near-infrared (VNIR) wavelengths less than 1100 nm. The accuracy of classifications produced from the feature sets tends to increase with the number of bands, but saturates at approximately 10 features, irrespective of the band selection method. However, the spatial autocorrelation of the resulting classifications continues to improve as the number of features is increased. Spatial autocorrelation is highest for features comprising broad and nonadjacent multiple bands. Features based on groups of correlated bands showed variable results, but generally under-performed the broad and multiple band features chosen based on spatial autocorrelation. The classification of the synthesized SPOT, MSS and TM sensors suggests that the band passes of these sensors are indeed well placed. However, the quantization of the data appears to be as significant as the number of bands. C1 W Virginia Univ, Dept Geol & Geog, Morgantown, WV 26506 USA. Pacific NW Natl Lab, Remote Sensing Grp, Richland, WA 99352 USA. RP Warner, TA (reprint author), W Virginia Univ, Dept Geol & Geog, Morgantown, WV 26506 USA. RI Warner, Timothy/F-1483-2010 NR 26 TC 12 Z9 12 U1 0 U2 3 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD MAY 20 PY 1999 VL 20 IS 8 BP 1601 EP 1616 DI 10.1080/014311699212632 PG 16 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 205NF UT WOS:000080826900009 ER PT J AU Hyman, JM Shashkov, M AF Hyman, JM Shashkov, M TI Mimetic discretizations for Maxwell's equations SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE Maxwell's equations; mimetic finite difference methods; discrete vector analysis; numerical methods ID LOGICALLY RECTANGULAR GRIDS; NATURAL DISCRETIZATIONS; TIME-DOMAIN; CURL; COMPUTATION; DIVERGENCE; OPERATORS; GRADIENT; SCHEME AB We have constructed reliable finite difference methods for approximating the solution to Maxwell's equations using accurate discrete analogs of differential operators that satisfy the identities and theorems of vector and tensor calculus in discrete form. The numerical approximation does nor have spurious modes and mimics many fundamental properties of the underlying physical problem including conservation laws, symmetries in the solution, and the nondivergence of particular vector fields. Numerical examples demonstrate the high quality of the method when the medium is strongly discontinuous and for nonorthogonal, nonsmooth computational grids. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Hyman, JM (reprint author), Univ Calif Los Alamos Natl Lab, T-7,MS-B284, Los Alamos, NM 87545 USA. NR 43 TC 79 Z9 79 U1 0 U2 2 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD MAY 20 PY 1999 VL 151 IS 2 BP 881 EP 909 DI 10.1006/jcph.1999.6225 PG 29 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 198YR UT WOS:000080452600019 ER PT J AU Cramer, C Grimsditch, M Saboungi, ML AF Cramer, C Grimsditch, M Saboungi, ML TI Raman and IR spectroscopy of silver iodide silver selenate fast ion-conducting glasses SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID SUPERIONIC GLASSES; ALPHA-AGI; VIBRATIONAL PROPERTIES; NEUTRON-DIFFRACTION; SPECTRA; TEMPERATURE; SCATTERING; MICROWAVE; DYNAMICS; SYSTEMS AB We report IR and Raman spectra obtained on a highly ion-conducting glass-forming system, x(AgI)(2).(1 - x)Ag2SeO4 with x = 0.35, 0.40, 0.46, 0.48, 0.50, 0.54. For 0.48(AgI)(2). 0.52Ag(2)SeO(4), spectra were recorded in a temperature range between room temperature and 573 K, probing the glassy, partly crystallized, and molten slates of the material. The spectra of the glasses are compared with those of the crystalline compounds Ag2SeO4 and alpha-AgI. Conclusions reached from the present work are consistent with those recently derived from neutron diffraction and dynamic conductivity measurements on the same materials. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Univ Munster, Inst Phys Chem, D-48149 Munster, Germany. RP Saboungi, ML (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Saboungi, Marie-Louise/C-5920-2013 OI Saboungi, Marie-Louise/0000-0002-0607-4815 NR 43 TC 6 Z9 7 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 20 PY 1999 VL 103 IS 20 BP 4018 EP 4022 DI 10.1021/jp983467t PG 5 WC Chemistry, Physical SC Chemistry GA 200XH UT WOS:000080565100006 ER PT J AU Hemmati, M Wilson, M Madden, PA AF Hemmati, M Wilson, M Madden, PA TI Structure of liquid Al2O3 from a computer simulation model SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID IONIC SYSTEMS; SIO2 GLASS; DYNAMICS; TRANSITIONS; AL-27 AB The combination of new containerless sample and high intensity synchrotron source technologies has enabled the X-ray diffraction pattern from a molten oxide (Al2O3) to be determined for the first time (Ansell et al. Phys. Rev. Left. 1997, 78, 464).(1) Here we show that the liquid-state diffraction pattern, predicted from a computer simulation with a potential derived from the ground-state crystal structure, agrees very well with the experimental data. Analysis of the local structure in the simulated melt shows that the Al3+ ions are not predominantly tetrahedrally coordinated, as surmised in the experimental study. Rather, six-, five- and four-coordinate Al3+ ions are found. Furthermore, evidence is presented for a tendency of the different coordinate species to spatially separate, and it is suggested that Al2O3 is close to a liquid-liquid phase separation of the type recently discussed by Angell and co-workers (ACS Symp. Ser. 1997, 676, 214).(2) C1 Univ Oxford, Oxford OX1 3QZ, England. Argonne Natl Lab, Argonne, IL 60439 USA. RP Wilson, M (reprint author), Univ Oxford, S Parks Rd, Oxford OX1 3QZ, England. OI Wilson, Mark/0000-0003-4599-7943 NR 27 TC 28 Z9 29 U1 0 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 20 PY 1999 VL 103 IS 20 BP 4023 EP 4028 DI 10.1021/jp983529f PG 6 WC Chemistry, Physical SC Chemistry GA 200XH UT WOS:000080565100007 ER PT J AU Maurice, D Head-Gordon, M AF Maurice, D Head-Gordon, M TI Analytical second derivatives for excited electronic states using the single excitation configuration interaction method: theory and application to benzo[a]pyrene and chalcone SO MOLECULAR PHYSICS LA English DT Article ID DENSITY-FUNCTIONAL THEORY; POTENTIAL-ENERGY SURFACES; COUPLED-CLUSTER METHOD; 2ND DERIVATIVES; TRANSITION; POLARIZABILITIES; SUBSTITUTIONS; EQUATION; STYRENE; CIS AB A compact formulation and a semi-direct implementation are described of analytical second derivatives of the single excitation configuration interaction (CIS) energy. CPU time, memory usage and disc storage all scale with the same power of system size as the ground state Hartree-Fock (HF) method, with a coefficient only 2 to 3 times larger. Thus usually analytical excited state CIS frequencies are feasible when HF frequencies are feasible. As a computational example, analytical CIS/3-21G frequencies for benzo[a]pyrene are calculated more efficiently than with finite differences. As a chemical application, analytical CIS/6-31G* frequencies are used to investigate non-planarity in the lowest pi --> pi* excited state of trans-chalcone. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Head-Gordon, M (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 45 TC 42 Z9 42 U1 2 U2 8 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0026-8976 J9 MOL PHYS JI Mol. Phys. PD MAY 20 PY 1999 VL 96 IS 10 BP 1533 EP 1541 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 198LW UT WOS:000080426500009 ER PT J AU Moll, U Lau, R Sypes, MA Gupta, MM Anderson, CW AF Moll, U Lau, R Sypes, MA Gupta, MM Anderson, CW TI DNA-PK, the DNA-activated protein kinase, is differentially expressed in normal and malignant human tissues SO ONCOGENE LA English DT Article DE cancer; DNA repair; DNA double-strand breaks; Brca2; Ku autoantigen; tissue-specific gene expression ID STRAND-BREAK REPAIR; HUMAN AUTOANTIGEN KU; RNA-POLYMERASE-II; V(D)J RECOMBINATION; IONIZING-RADIATION; BINDING PROTEIN; GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE; CATALYTIC SUBUNIT; GENE-PRODUCT; HUMAN MRE11 AB DNA-PK is a nuclear, serine/threonine protein kinase required for repairing DNA double-sh and breaks and for V(D)J recombination. To determine the distribution of DNA-PK in human tissues, we assayed paraffin-embedded sections of normal and cancerous tissues for DNA-PKcs and Ku80 by immunohistochemistry. We also assayed for Brca2, a human tumor suppressor gene that is implicated in the repair of DNA strand-breaks. Brca2 was strongly expressed in epithelial cells of the breast, endometrium, and thymus, in tingible body macrophages of follicular germinal centers of lymphoid tissue, and in reticuloendothelial cells in the spleen. DNA-PKcs and Ku80 expression was usually parallel, but both were expressed in a highly cell- and tissue-specific manner. The highest levels were observed in spermatogenic cells (but not in spermatozoa), and in neurons and glial cells of the central and autonomic nervous system. Neither protein was consistently expressed in liver nor in resting mammary epithelium, but lactating breast epithelium was strongly positive for DNA-PKcs and Ku80. In contrast to established human cell cultures, expression between cells in the same tissue was highly selective in the epidermis, exocrine pancreas, renal glomeruli, the red pulp of the spleen, and within cellular compartments of tonsils, lymph nodes, and thymus. Most cancerous tissues were consistently positive for DNA-PKcs and Ku80, except invasive carcinoma of the breast. DNA-PKcs, Ku80, and Ku70 mRNAs were expressed in all normal tissues with relatively little variation in levels. Our results suggest that the apparent absence of DNA-PKcs and Ku80 from some cells or tissues is a consequence of posttranscriptional mechanisms that regulate protein levels. C1 Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. SUNY Stony Brook, Dept Pathol, Stony Brook, NY 11794 USA. RP Anderson, CW (reprint author), Brookhaven Natl Lab, Dept Biol, 50 Bell Ave, Upton, NY 11973 USA. FU NIGMS NIH HHS [GM52825] NR 84 TC 67 Z9 81 U1 0 U2 3 PU STOCKTON PRESS PI BASINGSTOKE PA HOUNDMILLS, BASINGSTOKE RG21 6XS, HAMPSHIRE, ENGLAND SN 0950-9232 J9 ONCOGENE JI Oncogene PD MAY 20 PY 1999 VL 18 IS 20 BP 3114 EP 3126 DI 10.1038/sj.onc.1202640 PG 13 WC Biochemistry & Molecular Biology; Oncology; Cell Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Oncology; Cell Biology; Genetics & Heredity GA 197WB UT WOS:000080388000007 PM 10340383 ER PT J AU Benvenuti, C Calatroni, S Campisi, IE Darriulat, P Peck, MA Russo, R Valente, AM AF Benvenuti, C Calatroni, S Campisi, IE Darriulat, P Peck, MA Russo, R Valente, AM TI Study of the surface resistance of superconducting niobium films at 1.5 GHz SO PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS LA English DT Review DE microwave absorption; flux pinning; BCS model; niobium films ID II SUPERCONDUCTORS; RF SUPERCONDUCTIVITY; MAGNETIC-FIELD; FLUX CREEP; THIN-FILMS; CAVITIES; IMPEDANCE; HYDROGEN; NB; ALUMINUM AB A systematic study of superconducting properties of niobium films sputtered on the inner wall of radiofrequency cavities is presented. The measured quantities include in particular the response to 1.5 GHz microwaves, the critical temperature, the penetration depth and the magnetic penetration field. In addition to films grown in different gas discharges (Xe, Kr, Ar and Ar/Ne mixtures) and to films grown on substrates prepared under different conditions, the study also includes bulk niobium cavities, The surface resistance is analysed in terms of its dependence on temperature, on RF field and, when relevant, on the density of trapped fluxons. A simple parameterisation is found to give a good fit to the data. Once allowance for the presence of impurities and defects is made by means of a single parameter, the electron mean free path, good agreement with BCS theory is observed. The fluxon-induced losses are studied in detail and their dependence on RF field, on temperature and on the density of trapped fluxons is analysed. The residual resistance is observed to be essentially uncorrelated with the other variables, suggesting that it is dominantly extragranular. In occasions very low residual resistances, in the n Omega range, have been maintained over a broad range of RF field, indicating the absence of significant fundamental Limitations specific to the film technology in practical applications such as the production of accelerating cavities for particle accelerators. (C) 1999 Elsevier Science B.V. All rights reserved. C1 CERN, CH-1211 Geneva 23, Switzerland. TJNAF, Newport News, VA USA. Univ Salerno, I-84081 Baronissi, Italy. RP CERN, CH-1211 Geneva 23, Switzerland. EM darriulat@cern.ch RI Russo, Roberto/A-8576-2010 OI Russo, Roberto/0000-0001-9431-6265 NR 127 TC 48 Z9 48 U1 5 U2 17 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 EI 1873-2143 J9 PHYSICA C JI Physica C PD MAY 20 PY 1999 VL 316 IS 3-4 BP 153 EP 188 DI 10.1016/S0921-4534(99)00207-5 PG 36 WC Physics, Applied SC Physics GA 207CE UT WOS:000080917100001 ER PT J AU Arkani-Hamed, N Rattazzi, R AF Arkani-Hamed, N Rattazzi, R TI Exact results for non-holomorphic masses in softly broken supersymmetric gauge theories SO PHYSICS LETTERS B LA English DT Article ID ELECTRIC-MAGNETIC DUALITY; SYMMETRY-BREAKING; N=2 QCD; CONFINEMENT; SQCD AB We consider strongly coupled supersymmetric gauge theories softly broken by the addition of gaugino masses m(lambda) and (non-holomorphic) scalar masses m(2), taken to be small relative to the dynamical scale Lambda. For theories with a weakly coupled dual description in the infrared, we-compute exactly the leading soft masses for the "magnetic" degrees of freedom, with uncalculable corrections suppressed by powers of (m(lambda)/Lambda),(m/Lambda). The exact relations hold between the infrared fixed point "magnetic" soft masses and the ultraviolet fixed point "electric" soft masses, and correspond to a duality mapping for soft terms. We briefly discuss implications of these results for the vacuum structure of these theories. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. CERN, Div Theory, CH-1211 Geneva 23, Switzerland. RP Arkani-Hamed, N (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. OI Rattazzi, Riccardo/0000-0003-0276-017X NR 24 TC 43 Z9 43 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD MAY 20 PY 1999 VL 454 IS 3-4 BP 290 EP 296 DI 10.1016/S0370-2693(99)00406-2 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 205CB UT WOS:000080802800020 ER PT J AU Acciarri, M Achard, P Adriani, O Aguilar-Benitez, M Alcaraz, J Alemanmi, G Allaby, J Aloisio, A Alviggi, MG Ambrosi, G Anderhub, H Andreev, VP Angelescu, T Anselmo, F Arefiev, A Azemoon, T Aziz, T Bagnaia, P Baksay, L Balandras, A Ball, RC Banerjee, S Banerjee, S Banicz, K Barczyk, A Barillere, R Barone, L Bartalini, P Basile, M Battiston, R Bay, A Becattini, F Becker, U Behner, F Berdugo, J Berges, P Bertucci, B Betev, BL Bhattacharya, S Biasini, M Biland, A Blaising, JJ Blyth, SC Bobbink, GJ Bohm, A Boldizsar, L Borgia, B Bourilkov, D Bourquin, M Braccini, S Branson, JG Brigljevic, V Brochu, F Buffini, A Buijs, A Burger, JD Burger, WJ Busenitz, J Button, A Cai, XD Campanelli, M Capell, M Romeo, GC Carlino, G Cartacci, AM Casaus, J Castellini, G Cavallari, F Cavallo, N Cecchi, C Cerrada, M Cesaroni, F Chamizo, M Chang, YH Chaturvedi, UK Chemarin, M Chen, A Chen, G Chen, GM Chen, HF Chen, HS Chereau, X Chiefari, G Cifarelli, L Cindolo, F Civinini, C Clare, I Clare, R Coignet, G Colijn, AP Colino, N Costantini, S Cotorobai, F Cozzoni, B de la Cruz, B Csilling, A Dai, TS van Dalen, JA D'Alessandro, R de Asmundis, R Deglon, P Degre, A Deiters, K della Volpe, D Denes, P DeNotaristefani, F De Salvo, R Diemoz, M van Dierendonck, D Di Lodovico, F Dionisi, C Dittmar, M Dominguez, A Doria, A Dova, MT Duchesneau, P Dufournand, D Duinker, P Duran, I El Mamouni, H Engler, A Eppling, FJ Erne, FC Extermann, P Fabre, M Faccini, R Falagan, MA Falciano, S Favara, A Fay, J Fedin, O Felcini, M Ferguson, T Ferroni, F Fesefeldt, H Fiandrini, E Field, JH Filthaut, F Fisher, PH Fisk, I Forconi, G Fredj, L Freudenreich, K Furetta, C Galaktionov, Y Ganguli, SN Garcia-Abia, P Gataullin, M Gau, SS Gentile, S Gheordanescu, N Giagu, S Gong, ZF Grenier, G Gruenewald, MW van Gulik, R Gupta, VK Gurtu, A Gutay, LJ Haas, D Hasan, A Hatzifotiadou, D Hebbeker, T Herve, A Hidas, P Hirschfelder, J Hofer, H Holzner, G Hoorani, H Hou, SR Iashvili, I Jin, BN Jones, LW de Jong, P Josa-Mutuberria, I Khan, RA Kamrad, D Kapustinsky, JS Kaur, M Kienzle-Focacci, MN Kim, D Kim, DH Kim, JK Kim, SC Kinnison, WW Kirkby, J Kiss, D Kittel, W Klimentov, A Konig, AC Kopp, A Korolko, I Koutsenko, V Kraemer, RW Krenz, W Kunin, A Lacentre, P de Guevara, PL Laktineh, I Landi, G Lassila-Perini, K Laurikainen, P Lavorato, A Lebeau, M Lebedev, A Lebrun, P Lecomte, P Lecoq, P Le Coultre, P Lee, HJ Le Goff, JM Leiste, R Leonardi, E Levtchenko, P Li, C Lin, CH Lin, WT Linde, FL Lista, L Liu, ZA Lohmann, W Longo, E Lu, YS Lubelsmeyer, K Luci, C Luckey, D Lugnier, L Luminari, L Lustermann, W Ma, WG Maity, M Majumder, G Malgeri, L Malinin, A Mana, C Mangeol, D Marchesini, P Marian, G Martin, JP Marzano, F Massaro, GGG Mazumdar, K McNeil, RR Mele, S Merola, L Meschini, M Metzger, WJ von der Mey, M Migani, D Mihul, A Milcent, H Mirabelli, G Mnich, J Molnar, P Monteleoni, B Moulik, T Muanza, GS Muheim, F Muijs, AJM Napolitano, M Nessi-Tedaldi, F Newman, H Niessen, T Nisati, A Nowak, H Oh, YD Organtini, G Ostonen, R Palomares, C Pandoulas, D Paoletti, S Paolucci, P Park, HK Park, IH Pascale, G Passaleva, G Patricelli, S Paul, T Pauluzzi, M Paus, C Pauss, F Peach, D Pedace, M Pei, YJ Pensotti, S Perret-Gallix, D Petersen, B Petrak, S Piccolo, D Pieri, M Piroue, PA Pistolesi, E Plyaskin, V Pohl, M Pojidaev, V Postema, H Pothier, J Produit, N Prokofiev, D Quartieri, J Rahal-Callot, G Raja, N Rancoita, PG Raven, G Razis, P Ren, D Rescigno, M Reucroft, S van Rhee, T Riemann, S Riles, K Robohm, A Rodin, J Roe, BP Romero, L Rosier-Lees, S Rubio, JA Ruschmeier, D Rykaczewski, H Sakar, S Salicio, J Sanchez, E Sanders, MP Sarakinos, ME Schafer, C Schegelsky, V Schmidt-Kaerst, S Schmitz, D Scholz, N Schopper, H Schotanus, DJ Schwenke, J Schwering, G Sciacca, C Sciarrino, D Seganti, A Servoli, L Shevchenko, S Shivarov, N Shoutko, V Shukla, J Shumilov, E Shvorob, A Siedenburg, T Son, D Smith, B Spillantini, P Steuer, M Stickland, DP Stone, A Stone, H Stoyanov, B Straessner, A Sudhakar, K Sultanov, G Sun, LZ Suter, H Swain, JD Szillasi, Z Tang, XW Tauscher, L Taylor, L Timmermans, C Ting, SCC Ting, SM Tonwar, SC Toth, J Tully, C Tung, KL Uchida, Y Ulbricht, J Valente, E Vesztergombi, G Vetlitsky, I Vicinanza, D Viertel, G Villa, S Vivargent, M Vlachos, S Vodopianov, I Vogel, H Vogt, H Vorobiev, I Vorobyov, AA Vorvolakos, A Wadhwa, M Wallraff, W Wang, M Wang, XL Wang, ZM Weber, A Weber, M Wienemann, P Wilkens, H Wu, SX Wynhoff, S Xia, L Xu, ZZ Yang, BZ Yang, CG Yang, HJ Yang, M Ye, JB Yeh, SC You, JM Zalite, A Zalite, Y Zemp, P Zhang, ZP Zhu, GY Zhu, RY Zichichi, A Ziegler, F Zilizi, G Zoller, M AF Acciarri, M Achard, P Adriani, O Aguilar-Benitez, M Alcaraz, J Alemanmi, G Allaby, J Aloisio, A Alviggi, MG Ambrosi, G Anderhub, H Andreev, VP Angelescu, T Anselmo, F Arefiev, A Azemoon, T Aziz, T Bagnaia, P Baksay, L Balandras, A Ball, RC Banerjee, S Banerjee, S Banicz, K Barczyk, A Barillere, R Barone, L Bartalini, P Basile, M Battiston, R Bay, A Becattini, F Becker, U Behner, F Berdugo, J Berges, P Bertucci, B Betev, BL Bhattacharya, S Biasini, M Biland, A Blaising, JJ Blyth, SC Bobbink, GJ Bohm, A Boldizsar, L Borgia, B Bourilkov, D Bourquin, M Braccini, S Branson, JG Brigljevic, V Brochu, F Buffini, A Buijs, A Burger, JD Burger, WJ Busenitz, J Button, A Cai, XD Campanelli, M Capell, M Romeo, GC Carlino, G Cartacci, AM Casaus, J Castellini, G Cavallari, F Cavallo, N Cecchi, C Cerrada, M Cesaroni, F Chamizo, M Chang, YH Chaturvedi, UK Chemarin, M Chen, A Chen, G Chen, GM Chen, HF Chen, HS Chereau, X Chiefari, G Cifarelli, L Cindolo, F Civinini, C Clare, I Clare, R Coignet, G Colijn, AP Colino, N Costantini, S Cotorobai, F Cozzoni, B de la Cruz, B Csilling, A Dai, TS van Dalen, JA D'Alessandro, R de Asmundis, R Deglon, P Degre, A Deiters, K della Volpe, D Denes, P DeNotaristefani, F De Salvo, R Diemoz, M van Dierendonck, D Di Lodovico, F Dionisi, C Dittmar, M Dominguez, A Doria, A Dova, MT Duchesneau, P Dufournand, D Duinker, P Duran, I El Mamouni, H Engler, A Eppling, FJ Erne, FC Extermann, P Fabre, M Faccini, R Falagan, MA Falciano, S Favara, A Fay, J Fedin, O Felcini, M Ferguson, T Ferroni, F Fesefeldt, H Fiandrini, E Field, JH Filthaut, F Fisher, PH Fisk, I Forconi, G Fredj, L Freudenreich, K Furetta, C Galaktionov, Y Ganguli, SN Garcia-Abia, P Gataullin, M Gau, SS Gentile, S Gheordanescu, N Giagu, S Gong, ZF Grenier, G Gruenewald, MW van Gulik, R Gupta, VK Gurtu, A Gutay, LJ Haas, D Hasan, A Hatzifotiadou, D Hebbeker, T Herve, A Hidas, P Hirschfelder, J Hofer, H Holzner, G Hoorani, H Hou, SR Iashvili, I Jin, BN Jones, LW de Jong, P Josa-Mutuberria, I Khan, RA Kamrad, D Kapustinsky, JS Kaur, M Kienzle-Focacci, MN Kim, D Kim, DH Kim, JK Kim, SC Kinnison, WW Kirkby, J Kiss, D Kittel, W Klimentov, A Konig, AC Kopp, A Korolko, I Koutsenko, V Kraemer, RW Krenz, W Kunin, A Lacentre, P de Guevara, PL Laktineh, I Landi, G Lassila-Perini, K Laurikainen, P Lavorato, A Lebeau, M Lebedev, A Lebrun, P Lecomte, P Lecoq, P Le Coultre, P Lee, HJ Le Goff, JM Leiste, R Leonardi, E Levtchenko, P Li, C Lin, CH Lin, WT Linde, FL Lista, L Liu, ZA Lohmann, W Longo, E Lu, YS Lubelsmeyer, K Luci, C Luckey, D Lugnier, L Luminari, L Lustermann, W Ma, WG Maity, M Majumder, G Malgeri, L Malinin, A Mana, C Mangeol, D Marchesini, P Marian, G Martin, JP Marzano, F Massaro, GGG Mazumdar, K McNeil, RR Mele, S Merola, L Meschini, M Metzger, WJ von der Mey, M Migani, D Mihul, A Milcent, H Mirabelli, G Mnich, J Molnar, P Monteleoni, B Moulik, T Muanza, GS Muheim, F Muijs, AJM Napolitano, M Nessi-Tedaldi, F Newman, H Niessen, T Nisati, A Nowak, H Oh, YD Organtini, G Ostonen, R Palomares, C Pandoulas, D Paoletti, S Paolucci, P Park, HK Park, IH Pascale, G Passaleva, G Patricelli, S Paul, T Pauluzzi, M Paus, C Pauss, F Peach, D Pedace, M Pei, YJ Pensotti, S Perret-Gallix, D Petersen, B Petrak, S Piccolo, D Pieri, M Piroue, PA Pistolesi, E Plyaskin, V Pohl, M Pojidaev, V Postema, H Pothier, J Produit, N Prokofiev, D Quartieri, J Rahal-Callot, G Raja, N Rancoita, PG Raven, G Razis, P Ren, D Rescigno, M Reucroft, S van Rhee, T Riemann, S Riles, K Robohm, A Rodin, J Roe, BP Romero, L Rosier-Lees, S Rubio, JA Ruschmeier, D Rykaczewski, H Sakar, S Salicio, J Sanchez, E Sanders, MP Sarakinos, ME Schafer, C Schegelsky, V Schmidt-Kaerst, S Schmitz, D Scholz, N Schopper, H Schotanus, DJ Schwenke, J Schwering, G Sciacca, C Sciarrino, D Seganti, A Servoli, L Shevchenko, S Shivarov, N Shoutko, V Shukla, J Shumilov, E Shvorob, A Siedenburg, T Son, D Smith, B Spillantini, P Steuer, M Stickland, DP Stone, A Stone, H Stoyanov, B Straessner, A Sudhakar, K Sultanov, G Sun, LZ Suter, H Swain, JD Szillasi, Z Tang, XW Tauscher, L Taylor, L Timmermans, C Ting, SCC Ting, SM Tonwar, SC Toth, J Tully, C Tung, KL Uchida, Y Ulbricht, J Valente, E Vesztergombi, G Vetlitsky, I Vicinanza, D Viertel, G Villa, S Vivargent, M Vlachos, S Vodopianov, I Vogel, H Vogt, H Vorobiev, I Vorobyov, AA Vorvolakos, A Wadhwa, M Wallraff, W Wang, M Wang, XL Wang, ZM Weber, A Weber, M Wienemann, P Wilkens, H Wu, SX Wynhoff, S Xia, L Xu, ZZ Yang, BZ Yang, CG Yang, HJ Yang, M Ye, JB Yeh, SC You, JM Zalite, A Zalite, Y Zemp, P Zhang, ZP Zhu, GY Zhu, RY Zichichi, A Ziegler, F Zilizi, G Zoller, M TI Measurement of mass and width of the W boson at LEP SO PHYSICS LETTERS B LA English DT Article ID CARLO EVENT GENERATOR; CERN PBARP COLLIDER; FRAUTSCHI-SUURA EXPONENTIATION; ELECTRON-POSITRON COLLISIONS; DECAY BRANCHING FRACTIONS; ANGLE BHABHA SCATTERING; STATE QED CORRECTIONS; PAIR CROSS-SECTIONS; MONTE-CARLO; E(+)E(-) COLLISIONS AB We report on measurements of the mass and total decay width of the W boson with the L3 detector at LEP. W-pair events produced in e(+)e(-) interactions between 161 GeV and 183 GeV centre-of-mass energy are selected in a data sample corresponding to a total luminosity of 76.7 pb(-1). Combining all final states in W-pair production, the mass and total decay width of the W boson are determined to be m(W) = 80.61 +/- 0.15 GeV and Gamma(W) = 1.97 +/- 0.38 GeV, respectively. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Rhein Westfal TH Aachen, Inst Phys 1, D-52056 Aachen, Germany. Rhein Westfal TH Aachen, Inst Phys 3, D-52056 Aachen, Germany. NIKHEF, Natl Inst High Energy Phys, NL-1009 DB Amsterdam, Netherlands. Univ Amsterdam, NL-1009 DB Amsterdam, Netherlands. Univ Michigan, Ann Arbor, MI 48109 USA. ENSLAPP, LAPP, IN2P3, CNRS, F-74941 Annecy Le Vieux, France. Univ Basel, Inst Phys, CH-4056 Basel, Switzerland. Louisiana State Univ, Baton Rouge, LA 70803 USA. Inst High Energy Phys, Beijing 100039, Peoples R China. Humboldt Univ, D-10099 Berlin, Germany. Univ Bologna, I-40126 Bologna, Italy. INFN, Sezione Bologna, I-40126 Bologna, Italy. Tata Inst Fundamental Res, Bombay 400005, Maharashtra, India. Northeastern Univ, Boston, MA 02115 USA. Inst Atom Phys, R-76900 Bucharest, Romania. Univ Bucharest, R-76900 Bucharest, Romania. Hungarian Acad Sci, Cent Res Inst Phys, H-1525 Budapest 114, Hungary. MIT, Cambridge, MA 02139 USA. Ist Nazl Fis Nucl, Sezione Firenze, I-50125 Florence, Italy. Univ Florence, I-50125 Florence, Italy. CERN, European Lab Particle Phys, CH-1211 Geneva 23, Switzerland. FBLJA, World Lab, CH-1211 Geneva 23, Switzerland. Univ Geneva, CH-1211 Geneva, Switzerland. Univ Sci & Technol China, USTC, Hefei 230029, Peoples R China. Res Inst High Energy Phsy, SEFT, SF-00014 Helsinki, Finland. Univ Lausanne, CH-1015 Lausanne, Switzerland. Ist Nazl Fis Nucl, Sezione Lecce, I-73100 Lecce, Italy. Univ Lecce, I-73100 Lecce, Italy. Los Alamos Natl Lab, Los Alamos, NM 87544 USA. Univ Lyon 1, CNRS, IN2P3, Inst Phys Nucl, F-69622 Villeurbanne, France. CIEMAT, Ctr Invest Energet Medioambientales & Tecnol, E-28040 Madrid, Spain. Ist Nazl Fis Nucl, Sezione Milano, I-20133 Milan, Italy. ITEP, Inst Theoret & Expt Phys, Moscow, Russia. Ist Nazl Fis Nucl, Sezione Napoli, I-80125 Naples, Italy. Univ Naples Federico II, I-80125 Naples, Italy. Univ Cyprus, Dept Nat Sci, Nicosia, Cyprus. Univ Nijmegen, NL-6525 ED Nijmegen, Netherlands. Natl Inst Nucl Phys & High Energy Phys, NL-6525 ED Nijmegen, Netherlands. CALTECH, Pasadena, CA 91125 USA. Ist Nazl Fis Nucl, Sezione Perugia, I-06100 Perugia, Italy. Univ Perugia, I-06100 Perugia, Italy. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Princeton Univ, Princeton, NJ 08544 USA. Ist Nazl Fis Nucl, Sezione Roma, I-00185 Rome, Italy. Univ Roma La Sapienza, I-00185 Rome, Italy. Inst Nucl Phys, St Petersburg, Russia. RP Acciarri, M (reprint author), Rhein Westfal TH Aachen, Inst Phys 1, D-52056 Aachen, Germany. RI Ferguson, Thomas/O-3444-2014; Berdugo, Javier/A-2858-2015; D'Alessandro, Raffaello/F-5897-2015; Fiandrini, Emanuele/C-4549-2008; Lista, Luca/C-5719-2008; Kirkby, Jasper/A-4973-2012; Servoli, Leonello/E-6766-2012; bertucci, bruna/J-5237-2012; Cavallo, Nicola/F-8913-2012; Cerrada, Marcos/J-6934-2014; de la Cruz, Begona/K-7552-2014; Josa, Isabel/K-5184-2014; Vogel, Helmut/N-8882-2014; Achard, Pablo/C-2983-2009; Sanchez, Eusebio/H-5228-2015; Duran, Ignacio/H-7254-2015; Rancoita, Pier Giorgio/J-9896-2015; Hoorani, Hafeez/D-1791-2013; Palomares, Carmen/H-7783-2015; Fedin, Oleg/H-6753-2016; Di Lodovico, Francesca/L-9109-2016; Yang, Haijun/O-1055-2015; OI Castellini, Guido/0000-0002-0177-0643; Diemoz, Marcella/0000-0002-3810-8530; Doria, Alessandra/0000-0002-5381-2649; Faccini, Riccardo/0000-0003-2613-5141; Della Volpe, Domenico/0000-0001-8530-7447; Bertucci, Bruna/0000-0001-7584-293X; Filthaut, Frank/0000-0003-3338-2247; Ferguson, Thomas/0000-0001-5822-3731; Berdugo, Javier/0000-0002-7911-8532; D'Alessandro, Raffaello/0000-0001-7997-0306; Kirkby, Jasper/0000-0003-2341-9069; Servoli, Leonello/0000-0003-1725-9185; Cerrada, Marcos/0000-0003-0112-1691; Vogel, Helmut/0000-0002-6109-3023; Achard, Pablo/0000-0002-4865-3196; Sanchez, Eusebio/0000-0002-9646-8198; Rancoita, Pier Giorgio/0000-0002-1990-4283; Palomares, Carmen/0000-0003-4374-9065; Di Lodovico, Francesca/0000-0003-3952-2175; Longo, Egidio/0000-0001-6238-6787; Ambrosi, Giovanni/0000-0001-6977-9559 NR 77 TC 34 Z9 34 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 EI 1873-2445 J9 PHYS LETT B JI Phys. Lett. B PD MAY 20 PY 1999 VL 454 IS 3-4 BP 386 EP 398 DI 10.1016/S0370-2693(99)00348-2 PG 13 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 205CB UT WOS:000080802800035 ER PT J AU Jirsak, T Rodriguez, JA Hrbek, J AF Jirsak, T Rodriguez, JA Hrbek, J TI Chemistry of SO2 on Mo(110), MoO2/Mo(110) and Cs/Mo(110) surfaces: effects of O and Cs on the formation of SO3 and SO4 species SO SURFACE SCIENCE LA English DT Review DE ab initio quantum-chemical calculations; cesium; chemisorption; low index single crystal surfaces; molybdenum; oxides; sulfur dioxide; synchrotron radiation photoelectron spectroscopy ID ABSORPTION FINE-STRUCTURE; TRANSITION-METAL SURFACES; SULFUR-DIOXIDE ADSORPTION; OXIDE THIN-FILMS; PHOTOELECTRON-SPECTROSCOPY; ELECTRONIC-PROPERTIES; HIGH-TEMPERATURE; PROMOTED SULFIDATION; INITIAL OXIDATION; HYDROGEN-SULFIDE AB High-resolution synchrotron-based photoemission and X-ray photoelectron spectroscopy (XPS) have been used to study the interaction of SO2 with the Mo(110), O/Mo(110), MoO2/Mo(110) and Cs/Mo(110) surfaces. Ab initio self-consistent-held (SCF) calculations have been applied to provide information on the bonding of SO2 to Mo(110) and MoO2. At 300 K, sulfur dioxide completely decomposes on the Mo(110) surface (SO2 --> S-a + 2O(a)), while molecular species (SO2 and SO4) are also observed at 100 K. A SO2 multilayer, grown at large SO2 exposures at 100 K, completely disappears from the surface upon annealing to 160 K, leaving SO4, SO2 and atomic S. The molecular species SO4 and SO2 decompose entirely upon further annealing to 250 K. Several coordination modes for adsorbed SO2 (eta(1)-S a-top, eta(1)-S bridge, eta(2)-O,O bridge, eta(2)-S,O bridge) were examined using ab initio SCF calculations and a Mo-15 cluster model. It was found that adsorption geometries in which the molecule is di-coordinated via O,O or S,O are the most probable precursors for dissociation on Mo(110). From an electronic viewpoint, molybdenum is very well suited to adsorb and dissociate SO2, making this metal more reactive than any late transition metal. On a Mo7O14/PC4NC8 oxide cluster (PC and NC denote positive and negative point charges, +4e and -2e), a eta(2)-O,O bridge conformation is the most stable, but the adsorption energies and perturbations in the geometry of SO2 are much smaller than on the metal cluster (Mo-15). Experimental results confirm the theoretical expectations, and the Mo and O sites of the MoO2/Mo(110) system are not reactive toward SO2. Oxygen precovered surfaces do not facilitate the generation of SOx groups and accommodate only a small amount of atomic sulfur upon dosing of SO2 at 300 K. Addition of cesium to the Mo(110) surface substantially enhances its reactivity towards SO2. SO2 readily reacts with the Cs/Mo(110) surfaces at 300 K, and SO4 and SO3 species are produced. The thermal stability of the SO4 species on the Cs/Mo(110) system is much higher than that on the clean Mo(110) surface. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. EM rodrigez@bnl.gov RI Hrbek, Jan/I-1020-2013 NR 137 TC 31 Z9 32 U1 1 U2 23 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 EI 1879-2758 J9 SURF SCI JI Surf. Sci. PD MAY 20 PY 1999 VL 426 IS 3 BP 319 EP 335 DI 10.1016/S0039-6028(99)00287-3 PG 17 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 202UF UT WOS:000080670000009 ER PT J AU Barton, HA Bull, R Schultz, I Andersen, ME AF Barton, HA Bull, R Schultz, I Andersen, ME TI Dichloroacetate (DCA) dosimetry: interpreting DCA-induced liver cancer dose response and the potential for DCA to contribute to trichloroethylene-induced liver cancer SO TOXICOLOGY LETTERS LA English DT Article DE dichloroacetate; mouse liver cancer; pharmacokinetics; trichloroethylene ID MALE B6C3F1 MOUSE; SODIUM DICHLOROACETATE; TRICHLOROACETIC-ACID; SPECIES-DIFFERENCES; CHLORAL HYDRATE; VINYL-CHLORIDE; METABOLISM; MICE; CARCINOGENICITY; RAT AB Pharmacokinetic studies with dichloroacetate (DCA) provide insights into the likelihood that trichloroethylene-induced liver cancers arise from formation of DCA as a metabolite and the mode of action by which DCA induces liver cancer. A simple physiologically based pharmacokinetic model was developed to analyze DCA blood concentration data from mice unexposed to or pre-treated with DCA. The large first pass metabolism of DCA in the liver is significantly reduced by DCA pretreatment. Because DCA inhibits its own metabolism, large increases in area under the blood concentration curve occur at lower doses than would be predicted from single-dose pharmacokinetic studies with naive mice. The dose metrics associated with the incidence of liver tumors in contrast to the multiplicity of tumors per animal may be different, suggesting potentially different roles in the cancer process for DCA versus its metabolites. By linking a model for trichloroethylene (TCE) pharmacokinetics with the DCA model, maximum levels of DCA potentially produced from TCE were estimated to be at or below the analytical chemistry detection limits. In addition, the predicted levels of DCA would be too small to produce the observed liver cancers following corn oil gavage exposure of mice to TCE. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved. C1 KS Crump Grp Inc, ICF Kaiser, Res Triangle Pk, NC 27709 USA. Pacific NW Lab, Richland, WA 99352 USA. RP Barton, HA (reprint author), KS Crump Grp Inc, ICF Kaiser, POB 14348, Res Triangle Pk, NC 27709 USA. OI Andersen, Melvin/0000-0002-3894-4811 NR 23 TC 17 Z9 17 U1 0 U2 5 PU ELSEVIER SCI IRELAND LTD PI CLARE PA CUSTOMER RELATIONS MANAGER, BAY 15, SHANNON INDUSTRIAL ESTATE CO, CLARE, IRELAND SN 0378-4274 J9 TOXICOL LETT JI Toxicol. Lett. PD MAY 20 PY 1999 VL 106 IS 1 BP 9 EP 21 DI 10.1016/S0378-4274(99)00016-8 PG 13 WC Toxicology SC Toxicology GA 202NJ UT WOS:000080658700002 PM 10378446 ER PT J AU Jonas, U Shah, K Norvez, S Charych, DH AF Jonas, U Shah, K Norvez, S Charych, DH TI Reversible color switching and unusual solution polymerization of hydrazide-modified diacetylene lipids SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID POLYDIACETYLENE THIN-FILMS; THERMOCHROMIC PHASE-TRANSITION; MOLECULAR-ORBITAL METHODS; LANGMUIR-BLODGETT-FILMS; VALENCE BASIS-SETS; COLORIMETRIC DETECTION; ELECTRONIC-STRUCTURE; SUBSTITUTED POLYDIACETYLENES; CHROMATIC TRANSITION; ACID HYDRAZIDE AB Layer systems composed of polydiacetylene lipids are known to undergo an irreversible colorimetric transition from blue to red upon exposure to an external trigger (e.g., heat, pH change, specific ligand-target interaction). These optical transitions offer numerous possibilities toward the development of molecule-based sensory materials. Polymerization of the diacetylene systems usually occurs only in a highly ordered phase as a topochemical reaction, if the diacetylenic units are packed in an optimal orientation. A novel system based on hydrazide derivatives of single-chain diacetylene lipids is described. These materials show an unusual aggregation and polymerization behavior in organic solution, in contrast to the parent carboxylic acids. In addition, these hydrazide lipids undergo an unprecedented reversible color change (blue/red) in polymerized vesicles when the pH of the surrounding aqueous medium is cycled between acidic and basic conditions. This unusual behavior is attributed to the unique hydrogen-bonding pattern of the hydrazide headgroup, and was investigated by H-1 NMR, FTIR, UV-vis spectroscopy, and transmission electron microscopy. From the experimental data an ab initio computer model was developed to relate the observed colorimetric properties to intermolecular interactions. C1 Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Jonas, U (reprint author), Max Planck Inst Polymerforsch, Ackermannweg 10, D-55128 Mainz, Germany. RI Jonas, Ulrich/E-4492-2010 NR 45 TC 143 Z9 144 U1 2 U2 43 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD MAY 19 PY 1999 VL 121 IS 19 BP 4580 EP 4588 DI 10.1021/ja984190d PG 9 WC Chemistry, Multidisciplinary SC Chemistry GA 198MP UT WOS:000080428200005 ER PT J AU Lee, EC Muller, SJ AF Lee, EC Muller, SJ TI Flow light scattering studies of polymer coil conformation in solutions in extensional flow SO MACROMOLECULES LA English DT Article ID ELONGATIONAL FLOW; 4-ROLL MILL; MACROMOLECULAR DYNAMICS; VELOCITY-GRADIENTS; RELAXATION-TIME; DNA MOLECULE; SHEAR-FLOW; BIREFRINGENCE; SPECTROSCOPY; DEGRADATION AB The dynamics of isolated polymer chains in dilute solution under steady, extensional flow were investigated by means of flow light scattering. Both the orientation and deformation of the chains during flow were determined by analyzing the angular dependence of the scattered light intensity. The extensional flow field was imparted on the polymeric: fluids by a stagnation point flow in the center of a four-roll mill apparatus. The fluids studied were nearly monodisperse high molecular weight polystyrenes (HMPS) of various molecular weights dissolved in either the viscous solvent dioctyl phthalate (DOP) or a mixed solvent of low molecular weight polystyrene (LMPS) and dioctyl phthalate. The flow field in a Newtonian fluid of seeded glycerin was also examined by flow dynamic light scattering techniques and flow visualization to confirm the extensional flow field. Flow dynamic Light scattering and flow visualization results verified that the field generated by the four-roll mill was a reasonable approximation of planar extensional flow, under the conditions investigated. Flow (static) light scattering results confirmed that the polymer chains aligned completely with the stretch direction, as expected for this type of flow. The deformation of the chains, however, was significantly less than predicted by elastic dumbbell models. Also studied were the effects of molecular weight and solvent quality on the deformation of the polymer chains. Comparisons are drawn between polystyrene chains in the strong extensional flow field studied here and a steady shearing flow examined in a previous publication as well as with other studies in extensional flows. C1 Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Adv Mat, Berkeley, CA 94720 USA. RP Muller, SJ (reprint author), Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. NR 47 TC 27 Z9 28 U1 0 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD MAY 18 PY 1999 VL 32 IS 10 BP 3295 EP 3305 DI 10.1021/ma981277a PG 11 WC Polymer Science SC Polymer Science GA 198UD UT WOS:000080441900017 ER PT J AU Graessley, MW Hayward, RC Grest, GS AF Graessley, MW Hayward, RC Grest, GS TI Excluded-volume effects in polymer solutions. 2. Comparison of experimental results with numerical simulation data SO MACROMOLECULES LA English DT Article ID MONTE-CARLO; CRITICAL EXPONENTS; CHAIN; STIFFNESS; DYNAMICS AB The effect of excluded volume on the coil size of dilute linear polymers was investigated by off-lattice Monte Carlo simulations. The radius of gyration R-g was evaluated for a wide range of chain lengths at several temperatures and at the athermal condition. The theta temperature and the corresponding theta chain dimensions were established for the system, and the dependence of the size expansion factor, alpha(s) = R-g/(R-g)(theta), on chain length N and temperature T was examined. For long chains and at high temperatures, alpha(s) is a function of N/N(s)double dagger alone, where the length scale N(s)double dagger depends only on T. The form of this simulations-based master function compares favorably with alpha(s)(M/M(s)double dagger), an experimental master curve for linear polymers in good solvents, where M(s)double dagger depends only on polymer-solvent system. Comparisons when N(s)double dagger(T) and M(s)double dagger(system) are reduced to common units, numbers of Kuhn steps, strongly indicate that coil expansion in even the best of good solvents is small relative to that expected for truly athermal solutions. An explanation for this behavior is proposed, based on what would appear to be an inherent difference in the equation-of-state properties for polymeric and monomeric liquids. C1 Princeton Univ, Dept Chem Engn, Princeton, NJ 08544 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Exxon Res & Engn Co, Corp Res Sci Labs, Annandale, NJ 08801 USA. RP Graessley, MW (reprint author), 7496 Old Channel Trail, Montague, MI 49437 USA. RI Hayward, Ryan/P-4745-2016 OI Hayward, Ryan/0000-0001-6483-2234 NR 33 TC 31 Z9 31 U1 1 U2 19 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD MAY 18 PY 1999 VL 32 IS 10 BP 3510 EP 3517 PG 8 WC Polymer Science SC Polymer Science GA 198UD UT WOS:000080441900046 ER PT J AU Fleetwood, DM Winokur, PS Flament, O Leray, JL AF Fleetwood, DM Winokur, PS Flament, O Leray, JL TI Stability of trapped electrons in SiO2 SO APPLIED PHYSICS LETTERS LA English DT Article ID OXIDE-SEMICONDUCTOR CAPACITORS; BORDER TRAPS; INTERFACE STATES; SILICON DIOXIDE; POSITIVE CHARGE; SLOW STATES; HOLES; GENERATION; DEVICES AB Thermally stimulated current and capacitance voltage methods are used to investigate the thermal stability of trapped electrons associated with radiation-induced trapped positive charge in metaloxide-semiconductor capacitors. The density of deeply trapped electrons in radiation-hardened 45 nm oxides exceeds that of shallow electrons by a factor of similar to 3 after radiation exposure, and by up to a factor of 10 or more during biased annealing. Shallow electron traps anneal faster than deep traps, and exhibit response that is qualitatively consistent with existing models of compensated E-gamma' centers in SiO2. Deeper traps may be part of a different dipole complex, and/or have shifted energy levels that inhibit charge exchange with the Si. (C) 1999 American Institute of Physics. [S0003-6951(99)01220-6]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. CEA, DAM Ile France, F-91680 Bruyeres Le Chatel, France. RP Fleetwood, DM (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 21 TC 19 Z9 19 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 17 PY 1999 VL 74 IS 20 BP 2969 EP 2971 DI 10.1063/1.123982 PG 3 WC Physics, Applied SC Physics GA 197EU UT WOS:000080352700021 ER PT J AU Casteel, WJ Dixon, DA LeBlond, N Lock, PE Mercier, HPA Schrobilgen, GJ AF Casteel, WJ Dixon, DA LeBlond, N Lock, PE Mercier, HPA Schrobilgen, GJ TI Lewis acid behavior of ReO2F3: Synthesis of (ReO2F3)(infinity), ReO2F4-, Re2O4F7-, Re3O6F10- and ReO2F3(CH3CN) and study by NMR spectroscopy, Raman spectroscopy, and density functional theory calculations; and X-ray structures of [Li][ReO2F4], [K][Re2O4F7], [K][Re2O4F7]center dot 2ReO(2)F(3), [Cs][Re3O6F10], and ReO3F(CH3CN)(2)center dot CH3CN SO INORGANIC CHEMISTRY LA English DT Article ID OSMIUM TETRAFLUORIDE DIOXIDE; M = MO; CRYSTAL-STRUCTURE; MAGNETIC-RESONANCE; ANTIMONY PENTAFLUORIDE; COORDINATION CHEMISTRY; BOND-VALENCE; BASIS-SETS; F-19; ADDUCTS AB The reaction of Re2O7 with XeF6 in anhydrous HF provides a convenient route to high-purity ReO2F3. The fluoride acceptor and Lewis base properties of ReO2F3 have been investigated leading to the formation of [M][ReO2F4] [M = Li, Na, Cs, N(CH3)(4)], [K]Re2O4F7], [K]Re2O4F7]. 2ReO(2)F(3), [Cs][Re3O6F10], and ReO2F3(CH3CN). The ReO2F4-, Re2O4F7-, and Re3O6F10- anions and the ReO2F3(CH3CN) adduct have been characterized in the solid state by Raman spectroscopy, and the structures [Li][ReO2F4], [K][Re2O4F7], [K][Re2O4F7]. 2ReO(2)F(3), [Cs]-[Re3O6F10], and ReO3F(CH3CN)(2). CH3CN have been determined by X-ray crystallography. [Li][ReO2F4] crystallizes in the tetragonal system, space group P (4) over bar 2(l)m, with a = 4.727(3) Angstrom, c = 8.880(7) Angstrom, V = 198.4(7) Angstrom(3), and Z = 2 at 24 degrees C, R-1 = 0.0378, and wR(2) = 0.1029. [K][Re2O4F7] crystallizes in the monoclinic system, space group P2/n, with a = 5.4990(11) Angstrom, b = 5.1530(10) Angstrom, c = 14.753(3) Angstrom, beta = 95.68 degrees, V = 415.99(14) Angstrom(3), and Z = 2 at 20 degrees C, R-1 = 0.0473, and wR(2) = 0.1200. [K][Re2O4F7]. 2ReO(2)F(3) crystallizes in the monoclinic system, space group C2, with a = 27.32(2) Angstrom, b = 5.274(5) Angstrom, c = 5.355(3) Angstrom, beta = 99.53(4)degrees, V = 760.9(11) Angstrom(3), and Z = 2 at -60 degrees C, R-1 = 0.0238, and wR(2) = 0.0645. [Cs][Re3O6F10] crystallizes in the triclinic system, space group P (1) over bar, with a = 7.011(1) Angstrom, b = 9.773(2) Angstrom, c = 10.331(2) Angstrom, alpha = 113.73(1)degrees, beta = 91.05(2)degrees, gamma = 92.42(2)degrees, V = 647.4(2) Angstrom(3), and Z = 2 at -118 degrees C, R-1 = 0.0522, and wR(2) = 0.0529. ReO3F(CH3CN). CH3CN crystallizes in the orthorhombic system, space group Pnma, with a = 9.138(3) Angstrom, b = 12.518(5) Angstrom, V = 1045.4(7) Angstrom(3), and Z = 4 at -63 degrees C, R-1 = 0.0198, and WR2 = 0.0605. The structure of ReO2F4- consists of a cis-dioxo arrangement of Re-O double bonds in which the Re-F bonds trans to the oxygen atoms are significantly lengthened as a result of the trans influence of the oxygens. The Re2O4F7- and Re3O6F10- anions and polymeric ReO2F3 are open chains containing fluorine-bridged ReO2F4 units in which each pair of Re-O bonds are cis to each other and the fluorine bridges are trans to oxygens. The trans influence of the oxygens is manifested by elongated terminal Re-F bonds trans to Re-O bonds as in ReO2F4- and by the occurrence of both fluorine bridges trans to Re-O bonds. Fluorine-19 NMR spectra show that ReO2F4-, Re2O4F7-, and ReO2F3(CH3CN) have cis-dioxo arrangements in CH3CN solution. Density functional theory calculations at the local and nonlocal levels confirm that the cis-dioxo isomers of ReO2F4- and ReO2F3(CH3CN), where CH3CN is bonded trans to an oxygen, are the energy-minimized structures. The adduct ReO3F(CH3CN)(2). CH3CN was obtained by hydrolysis of ReO2F3(CH3CN), and was shown by X-ray crystallography to have a facial arrangement of oxygen atoms on rhenium. C1 McMaster Univ, Dept Chem, Hamilton, ON L8S 4M1, Canada. Pacific NW Natl Lab, William R Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Schrobilgen, GJ (reprint author), McMaster Univ, Dept Chem, 1280 Main St W, Hamilton, ON L8S 4M1, Canada. NR 81 TC 23 Z9 23 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD MAY 17 PY 1999 VL 38 IS 10 BP 2340 EP 2358 DI 10.1021/ic980695t PG 19 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 199BH UT WOS:000080459200016 ER PT J AU Boyle, TJ Alam, TM Tafoya, CJ Mechenbier, ER Ziller, JW AF Boyle, TJ Alam, TM Tafoya, CJ Mechenbier, ER Ziller, JW TI Syntheses, characterizations, and X-ray structures of alkali metal derivatives of titanium(IV) neopentoxides SO INORGANIC CHEMISTRY LA English DT Article ID THIN-FILMS; PRECURSORS; ALKOXIDES AB Reactions of titanium(IV) neopentoxide, [Ti(mu-Oneo-Pe)(Oneo-Pe)(3)](2) (1, Oneo-Pe = OCH2CMe3), with alkali neopentoxides (AOneo-Pe) resulted in the isolation of the dimeric complexes [ATi(Oneo-Pe)(5)](2) [A = Li (2), Na (3), and K (4)], independent of the alkali metal investigated. Each compound was characterized by solution and solid-state multinuclear NMR, isopiestic molecular weight determination, and/or single-crystal X-ray diffraction. In the solid state, both 2 and 4 were found to adopt a standard [MM'(OR)(5)](2) arrangement, wherein the Ti metals are in a distorted trigonal-bipyramidal geometry and each alkali metal center is four-coordinated. Suitable crystals of 3 were not isolated, but solid-state MAS (O-17, C-13, (x)A) NMR spectroscopy indicated that the solid-state structure of 3 was consistent with its congeners. Multinuclear (H-1, Li-7, C-13, O-17, Na-23) solution NMR spectroscopy data in toluene revealed that 2 exists in a complex multinuclear equilibrium, whereas 3 and 4 exist as mononuclear species in solution. C1 Sandia Natl Labs, Adv Mat Lab, Albuquerque, NM 87106 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA. RP Boyle, TJ (reprint author), Sandia Natl Labs, Adv Mat Lab, 1001 Univ Blvd SE, Albuquerque, NM 87106 USA. NR 26 TC 20 Z9 20 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD MAY 17 PY 1999 VL 38 IS 10 BP 2422 EP 2428 DI 10.1021/ic981143d PG 7 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 199BH UT WOS:000080459200026 ER PT J AU Ferman, J Kakareka, JP Klooster, WT Mullin, JL Quattrucci, J Ricci, JS Tracy, HJ Vining, WJ Wallace, S AF Ferman, J Kakareka, JP Klooster, WT Mullin, JL Quattrucci, J Ricci, JS Tracy, HJ Vining, WJ Wallace, S TI Electrochemical and photophysical properties of a series of group-14 metalloles SO INORGANIC CHEMISTRY LA English DT Article AB A series of six group-14 dimethyl- or diphenyl-tetraphenylmetallacyclopentadienes were synthesized and characterized by their spectroscopic and electrochemical properties. The group-14 elements investigated were silicon, germanium, and tin. (The compounds are designated according to the heteroatom and the substituent on the heteroatom, i.e., SiMe, SiPh, ..., SnPh.) Five of the six compounds luminesce in both the solid state and in solution. The emission maxima of SiPh, GePh, and SnPh are invariant to a change in the heteroatom, while for SiMe, GeMe, and SnMe there is a strong dependence of the emission maxima on the identity of the heteroatom. SiMe emits at a longer wavelength than GeMe, while SnMe is not luminescent. The dramatic luminescence difference between the two tin compounds was investigated. C-13 NMR coupling to Sn-119/117, observed in both SnMe and SnPh, was used to make C-13 NMR resonance assignments. Qualitative results of semiempirical molecular orbital calculations support the C-13 NMR assignments. The crystal structure data for SnPh was obtained at 20 degrees C: a = 10.353(2) Angstrom, b = 16.679(2) Angstrom, c = 9.482(1) Angstrom, alpha = 99.91(1)degrees, beta = 106.33(1)degrees, gamma = 77.80(1)degrees with Z = 2 in space group . It is proposed that the increased electron density at tin in SnMe is responsible for the deactivation of the emissive state. The presence of phenyl substituents in SnPh serves to stabilize the emissive state and luminescence is observed. C1 Univ So Maine, Dept Chem, Portland, ME 04103 USA. Univ Massachusetts, Dept Chem, Amherst, MA 01003 USA. Florida Gulf Coast Univ, Coll Arts & Sci, Ft Myers, FL USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Univ New England, Dept Life Sci, Biddeford, ME USA. RP Tracy, HJ (reprint author), Univ So Maine, Dept Chem, Portland, ME 04103 USA. NR 27 TC 49 Z9 50 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD MAY 17 PY 1999 VL 38 IS 10 BP 2464 EP 2472 DI 10.1021/ic980662d PG 9 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 199BH UT WOS:000080459200032 ER PT J AU Graudejus, O Elder, SH Lucier, GM Shen, C Bartlett, N AF Graudejus, O Elder, SH Lucier, GM Shen, C Bartlett, N TI Room temperature syntheses of AuF6- and PtF6- salts, Ag+AuF6-, Ag2+PtF62-, and Ag2+PdF62- and an estimate for E(MF6-) [M = Pt, Pd] SO INORGANIC CHEMISTRY LA English DT Article ID ANHYDROUS HYDROGEN-FLUORIDE; MAGNETIC-PROPERTIES; CRYSTAL-STRUCTURE; OXIDATION; PLATINUM; TRIFLUORIDE; RUTHENIUM; GOLD; AGF3; RU AB Solutions of AuF4- or PtF62- salts, prepared from the metals at similar to 20 degrees C, in liquid anhydrous hydrogen fluoride (aHF), made basic with alkali fluorides, are further oxidized by photodissociated F-2 (visible or near-UV Light) to give AuF6- or PtF6- salts, including O2+AuF6- (with O-2 in the F-2). Similar photochemical oxidation of PdF62- salts does not occur. This new synthetic approach has provided LiAuF6 and LiPtF6 for the first time, each of which has the LiSbF6 type () structure with (hexagonal cell): LiAuF6, a = 4.9953(9) Angstrom, c = 13.704(3) Angstrom, V/Z = 98.71(6) Angstrom(3); LiPtF6, a = 5.0236(7) Angstrom, c = 13.623(2) Angstrom, V/Z = 99.25(5) Angstrom(3). Interaction of AuF6- with Ag+ gives Ag+AuF6- (, a = 5.283(3) Angstrom, c = 15.053 Angstrom, V/Z = 121.3(2) Angstrom(3)), whereas PtF62- or PdF62- stabilize Ag2+ as Ag2+Pt(Pd)F-6(2-) (; AgPtF6: a = 5.049(8) Angstrom, c = 14.46(2) Angstrom, V/Z = 106.4(5) Angstrom(3); and AgPdF6, a = 5.00(4) Angstrom, c = 14.6(2) Angstrom, V/Z = 105(3) Angstrom(3)). New cubic modifications (probable space group Ia3) have been found for AgMF6 (M, a value, Angstrom): Ru, 9.653(10); Os, 9.7318(9); Ir, 9.704(2). The preference for Ag2+Pt(Pd)F-6(2-) over Ag+Pt(Pd)F-6(-) is attributed to a second electron affinity of Pt(Pd)F-6, E(Pt(Pd)F-6(-)) > 60 kcal mol(-1). C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Chem, Berkeley, CA 94720 USA. RP Bartlett, N (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. NR 50 TC 55 Z9 55 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD MAY 17 PY 1999 VL 38 IS 10 BP 2503 EP 2509 DI 10.1021/ic981397z PG 7 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 199BH UT WOS:000080459200037 ER PT J AU Hutchison, K Morris, JC Nile, TA Walsh, JL Thompson, DW Petersen, JD Schoonover, JR AF Hutchison, K Morris, JC Nile, TA Walsh, JL Thompson, DW Petersen, JD Schoonover, JR TI Spectroscopic and photophysical properties of complexes of 4 '-ferrocenyl-2,2 ': 6 ',2 ''-terpyridine and related ligands SO INORGANIC CHEMISTRY LA English DT Article ID MLCT EXCITED-STATES; CHARGE-TRANSFER; ENERGY-TRANSFER; ABSORPTION-SPECTRA; ELECTRON-TRANSFER; METAL-COMPLEXES; METALLOSUPRAMOLECULAR CHEMISTRY; RUTHENIUM(II) COMPLEXES; DINUCLEAR COMPLEXES; PHOTOINDUCED ENERGY AB 4'-(Ferrocenyl)-2,2':6',2 "-terpyridine (Fctpy) and 4'-(4-pyridyl)-2,2':6',2 "-terpyridine (pytpy) were prepared from the corresponding ferrocene- and pyridinecarboxaldehyle and 2-acetylpyridine using the Krohnke synthetic methodology. Metal complexes, [M(Fctpy)(2)](PF6)(2) (M = Ru, Fe, Zn), [Ru(tpy)(Fctpy)](PF6)(2) (tpy = 2,2':6',6 "-terpyridine), and [Ru(pytpy)(2)](PF6)(2) were prepared and characterized. Cyclic voltammetric analysis indicated Ru-III/II and ferrocenium/ferrocene redox couples near expected potentials (Ru-III/II similar to 1.3 V and ferrocenium/ferrocene similar to 0.6 V vs Ag/AgCl). In addition to dominant pi(tpy) --> pi(tpy)* UV absorptions near 240 and 280 nm and d(pi)(Ru) --> pi(tpy)* MLCT absorptions around 480 nm, the complexes [Ru(Fctpy)(2)](PF6)(2) and [Ru(tpy)(Fctpy)](PF6)(2) exhibit an unusual absorption band around 530 nm. Resonance Raman measurements indicate that this band is due to a (1)[(d(pi)(Fc))(6)] --> (1)[(d(pi)(Fc))(5)(pi*(Ru)(tpy))(1)] transition. For [Ru(Fctpy)(2)](PF6)(2) and [Ru(tpy)(Fctpy)](PF6)(2), excited-state emission and lifetime measurements indicated an upper-limit emission quantum yield of 0.003 and an upper-limit emission lifetime of 0.025 mu s. The influence of the ferrocenyl site on excited-state decay is discussed, and an excited-state energy level diagram is proposed. C1 Univ N Carolina, Dept Chem, Greensboro, NC 27412 USA. Wayne State Univ, Dept Chem, Detroit, MI 48202 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Walsh, JL (reprint author), Univ N Carolina, Dept Chem, Greensboro, NC 27412 USA. NR 64 TC 60 Z9 60 U1 0 U2 18 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 EI 1520-510X J9 INORG CHEM JI Inorg. Chem. PD MAY 17 PY 1999 VL 38 IS 10 BP 2516 EP 2523 DI 10.1021/ic980798b PG 8 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 199BH UT WOS:000080459200039 ER PT J AU Eager, MD Espenson, JH AF Eager, MD Espenson, JH TI Activation of molecular oxygen in systems containing methyltrioxorhenium and its derivatives SO INORGANIC CHEMISTRY LA English DT Article ID MAIN-GROUP ELEMENTS; RE-RE BOND; METHYLRHENIUM TRIOXIDE; TRANSITION-METALS; MULTIPLE BONDS; ORGANORHENIUM OXIDES; COMPUTER-SIMULATION; RHENIUM(V); COMPLEXES; OXIDATIONS AB The activation of molecular oxygen arises from its reaction with a dioxorhenium(V) complex, giving the peroxo complex that rapidly converts phosphine to phosphine oxide. C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Chem, Ames, IA 50011 USA. RP Espenson, JH (reprint author), Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. NR 16 TC 14 Z9 14 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD MAY 17 PY 1999 VL 38 IS 10 BP 2533 EP + DI 10.1021/ic981388q PG 4 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 199BH UT WOS:000080459200043 ER PT J AU George, GN Pickering, IJ Kisker, C AF George, GN Pickering, IJ Kisker, C TI X-ray absorption spectroscopy of chicken sulfite oxidase crystals SO INORGANIC CHEMISTRY LA English DT Article ID MOLYBDENUM-COFACTOR; ELECTRON-TRANSFER; FINE-STRUCTURE; SITE; KINETICS; ENZYMES AB We have investigated the active site of crystalline sulfite oxidase using X-ray absorption spectroscopy. Our results indicate that the crystalline preparation contains molybdenum in the fully oxidized Mo-VI form, with a local structure that in solution, with two Mo=O ligands at 1.71 Angstrom and three Mo-S at 2.41 Angstrom. C1 Stanford Univ, Stanford Synchrotron Radiat Lab, SLAC, Stanford, CA 94309 USA. SUNY Stony Brook, Dept Pharmacol Sci, Stony Brook, NY 11794 USA. RP George, GN (reprint author), Stanford Univ, Stanford Synchrotron Radiat Lab, SLAC, POB 4349,MS 69, Stanford, CA 94309 USA. RI George, Graham/E-3290-2013; Pickering, Ingrid/A-4547-2013; OI Pickering, Ingrid/0000-0002-0936-2994 NR 20 TC 52 Z9 52 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 EI 1520-510X J9 INORG CHEM JI Inorg. Chem. PD MAY 17 PY 1999 VL 38 IS 10 BP 2539 EP + DI 10.1021/ic981451b PG 3 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 199BH UT WOS:000080459200045 ER PT J AU Lopez, RE Dodelson, S Heckler, A Turner, MS AF Lopez, RE Dodelson, S Heckler, A Turner, MS TI Precision detection of the cosmic neutrino background SO PHYSICAL REVIEW LETTERS LA English DT Article ID EARLY UNIVERSE; ANISOTROPY EXPERIMENTS; MICROWAVE; POLARIZATION; NUCLEOSYNTHESIS AB In the standard big bang cosmology the canonical value fur the ratio of relic neutrinos to cosmic microwave background (CMB) photons is 9/11. Within the framework of the standard model of particle physics there are small corrections, in sum about 1%, due to slight heating of neutrinos by electron-positron annihilations and finite-temperature QED effects. We show that this leads to changes in the predicted CMB anisotropies that will bias determination of the other cosmological parameters if not correctly taken into account. These changes might be detected by future satellite experiments. C1 Univ Chicago, Dept Phys, Chicago, IL 60637 USA. Fermi Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. Ohio State Univ, Dept Phys, Columbus, OH 43210 USA. Univ Chicago, Enrico Fermi Inst, Dept Astron & Astrophys, Chicago, IL 60637 USA. RP Lopez, RE (reprint author), Univ Chicago, Dept Phys, Chicago, IL 60637 USA. RI Heckler, Andrew/A-7291-2010 OI Heckler, Andrew/0000-0001-5494-7855 NR 28 TC 67 Z9 67 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 17 PY 1999 VL 82 IS 20 BP 3952 EP 3955 DI 10.1103/PhysRevLett.82.3952 PG 4 WC Physics, Multidisciplinary SC Physics GA 196QW UT WOS:000080319900007 ER PT J AU Harss, B Greene, JP Henderson, D Janssens, RVF Jiang, CL Nolen, J Pardo, RC Rehm, KE Schiffer, JP Siemssen, RH Sonzogni, AA Uusitalo, J Wiedenhover, I Paul, M Wang, TF Borasi, F Segel, RE Blackmon, JC Smith, MS Chen, A Parker, P AF Harss, B Greene, JP Henderson, D Janssens, RVF Jiang, CL Nolen, J Pardo, RC Rehm, KE Schiffer, JP Siemssen, RH Sonzogni, AA Uusitalo, J Wiedenhover, I Paul, M Wang, TF Borasi, F Segel, RE Blackmon, JC Smith, MS Chen, A Parker, P TI Stellar reactions with short-lived nuclei: F-17(p, alpha)O-14 SO PHYSICAL REVIEW LETTERS LA English DT Article ID F-18(P,ALPHA)O-15 REACTION; RADIOACTIVE BEAMS; ENERGY AB A method has been developed that can provide beams of many short-lived nuclei of interest in nucleosynthesis along the up process path. With a F-17 beam (T-1/2 = 64 s) the excitation function of the F-17(p, alpha)O-14 reaction was measured to determine properties of excited states in Ne-18. These states influence the rate of the O-14(alpha, p)F-17 reaction which is important for understanding energy generation and nucleosynthesis in x-ray bursts. The present direct measurements yield a pattern of resonances and cross sections which differ substantially from previous estimates. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Tech Univ Munich, Phys Dept E12, D-8000 Munich, Germany. Hebrew Univ Jerusalem, Jerusalem, Israel. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Northwestern Univ, Evanston, IL 60439 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Yale Univ, Wright Nucl Struct Lab, New Haven, CT 06520 USA. RP Harss, B (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 18 TC 48 Z9 48 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 17 PY 1999 VL 82 IS 20 BP 3964 EP 3967 DI 10.1103/PhysRevLett.82.3964 PG 4 WC Physics, Multidisciplinary SC Physics GA 196QW UT WOS:000080319900010 ER PT J AU Schultz, DR Strayer, MR Wells, JC AF Schultz, DR Strayer, MR Wells, JC TI Lattice, time-dependent Schrodinger equation solution for ion-atom collisions SO PHYSICAL REVIEW LETTERS LA English DT Article ID PROTON-HYDROGEN COLLISIONS; H+-H COLLISIONS; CLOSE-COUPLING METHOD; CHARGE-TRANSFER; CROSS-SECTION; H(2S) ATOMS; EXCITATION; IONIZATION; STATE; OSCILLATIONS AB Utilizing a lattice representation of the wave function and operators, we have solved the time-dependent Schrodinger equation over a wide range of collision energies and impact parameters to study excitation to low-lying states in collisions of protons with atomic hydrogen. The technique circumvents many of the shortcomings of commonly applied close coupling and perturbation theory approaches that are valid only in restricted regimes. Thus, the investigation represents a stop towards precise knowledge of the dynamical quantities characterizing this and other fundamental collisions. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Ctr Computat Sci, Oak Ridge, TN 37831 USA. RP Schultz, DR (reprint author), Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. RI Wells, Jack/D-3675-2016 OI Wells, Jack/0000-0002-5083-3030 NR 27 TC 59 Z9 59 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 17 PY 1999 VL 82 IS 20 BP 3976 EP 3979 DI 10.1103/PhysRevLett.82.3976 PG 4 WC Physics, Multidisciplinary SC Physics GA 196QW UT WOS:000080319900013 ER PT J AU Sanchez, EJ Novotny, L Xie, XS AF Sanchez, EJ Novotny, L Xie, XS TI Near-field fluorescence microscopy based on two-photon excitation with metal tips SO PHYSICAL REVIEW LETTERS LA English DT Article ID FOCUSED ION-BEAMS; OPTICAL MICROSCOPY; ENHANCEMENT AB We present a new scheme for near-field fluorescence imaging using a metal tip illuminated with femtosecond laser pulses of proper polarization. The strongly enhanced electric field at the metal tip (approximate to 15 nm end diameter) results in a localized excitation source for molecular fluorescence. Excitation of the sample via two-photon absorption provides good image contrast due to the quadratic intensity dependence. technique. The spatial resolution is shown to be better than that of the conventional aperture We used the technique to image fragments of photosynthetic membranes, as well as J-aggregates with spatial resolutions on the order of 20 nm. C1 Pacific NW Lab, William R Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. Portland State Univ, Dept Phys, Environm Sci & Resources Program, Portland, OR 97207 USA. RP Sanchez, EJ (reprint author), Harvard Univ, Dept Chem & Biol Chem, 12 Oxford St, Cambridge, MA 02138 USA. NR 23 TC 550 Z9 558 U1 8 U2 74 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 17 PY 1999 VL 82 IS 20 BP 4014 EP 4017 DI 10.1103/PhysRevLett.82.4014 PG 4 WC Physics, Multidisciplinary SC Physics GA 196QW UT WOS:000080319900023 ER PT J AU Bogicevic, A Jennison, DR AF Bogicevic, A Jennison, DR TI Variations in the nature of metal adsorption on ultrathin Al2O3 films SO PHYSICAL REVIEW LETTERS LA English DT Article ID OXIDE SURFACES; APPROXIMATIONS; EXCHANGE; SOLIDS; ATOMS AB First-principles density-functional calculations are used to study metal adsorption (Li, K, Y, Nb, Ru, Pd, Pt, Cu, Ag, Au, and Al at 1/3-4 monolayer coverages) atop 5 Angstrom Al2O3 films on Al(111). The oxide-metal bond is ionic at low coverages but, with interesting exceptions, caused by polarization at high coverages where the overlayer is metallic. Binding trends are explained in terms of simple concepts. increasing overlayer thickness can cause the adsorbate-oxide interface structure to change, and while some metals wet, most do not. C1 Sandia Natl Labs, Surface & Interface Sci Dept, Albuquerque, NM 87185 USA. RP Sandia Natl Labs, Surface & Interface Sci Dept, POB 5800, Albuquerque, NM 87185 USA. NR 21 TC 151 Z9 152 U1 0 U2 21 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 17 PY 1999 VL 82 IS 20 BP 4050 EP 4053 DI 10.1103/PhysRevLett.82.4050 PG 4 WC Physics, Multidisciplinary SC Physics GA 196QW UT WOS:000080319900032 ER PT J AU Rotenberg, E Chung, JW Kevan, SD AF Rotenberg, E Chung, JW Kevan, SD TI Spin-orbit coupling induced surface band splitting in Li/W(110) and Li/Mo(110) SO PHYSICAL REVIEW LETTERS LA English DT Article ID MAGNETIC CIRCULAR-DICHROISM; ANISOTROPY; W(110); TRANSITION; COVERAGE; MOMENT; CO AB The broken symmetry at surfaces can give rise to a nonzero spin-orbit splitting of valence bands. We observe such a splitting of the d-derived surface state on W(110) and, to a lesser extent, on Mo(110), and follow the evolution of the splitting as monovalent atoms an adsorbed. The observed evolution is directly relevant to recent observations of altered orbital magnetic structure versus adsorbate coverage in magnetic materials. We propose a spin ordering for the associated Fermi contours which has important implications for spin excitations at surfaces. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source, Berkeley, CA 94720 USA. POSTECH, Dept Phys, Pohang 790784, South Korea. Univ Oregon, Dept Phys, Eugene, OR 97403 USA. RP Rotenberg, E (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source, Berkeley, CA 94720 USA. RI Rotenberg, Eli/B-3700-2009; Kevan, Stephen/F-6415-2010 OI Rotenberg, Eli/0000-0002-3979-8844; Kevan, Stephen/0000-0002-4621-9142 NR 27 TC 100 Z9 100 U1 1 U2 11 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 17 PY 1999 VL 82 IS 20 BP 4066 EP 4069 DI 10.1103/PhysRevLett.82.4066 PG 4 WC Physics, Multidisciplinary SC Physics GA 196QW UT WOS:000080319900036 ER PT J AU Gammel, PL Bishop, DJ Eskildsen, MR Mortensen, K Andsersen, NH Fisher, IR Cheon, KO Canfield, PC Kogan, VG AF Gammel, PL Bishop, DJ Eskildsen, MR Mortensen, K Andsersen, NH Fisher, IR Cheon, KO Canfield, PC Kogan, VG TI Systematic studies of the square-hexagonal flux line lattice transition in Lu(Ni1-xCox)(2)B2C: The role of nonlocality SO PHYSICAL REVIEW LETTERS LA English DT Article ID SUPERCONDUCTORS; MAGNETISM; ERNI2B2C; COEXISTENCE; STATE AB We have studied, using small angle neutron scattering, the Bur line lattice square to hexagonal symmetry transition in single crystal Lu(Ni1-xCox)(2)B2C. Low Co concentrations (x < 0.1) which reduce the mean free path and increase the coherence length, also move the structural transition to higher fields than in the undoped system. These data, quantitatively understood within the framework of a theory that includes nonlocal corrections to the London model due to the Fermi surface anisotropy, can be modeled using a simple ratio of the nonlocality range to the intervortex spacing. C1 AT&T Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. Riso Natl Lab, DK-4000 Roskilde, Denmark. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Gammel, PL (reprint author), AT&T Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. RI Mortensen, Kell/A-5066-2009; Eskildsen, Morten/E-7779-2011; Canfield, Paul/H-2698-2014 OI Mortensen, Kell/0000-0002-8998-9390; NR 19 TC 52 Z9 52 U1 1 U2 7 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 17 PY 1999 VL 82 IS 20 BP 4082 EP 4085 DI 10.1103/PhysRevLett.82.4082 PG 4 WC Physics, Multidisciplinary SC Physics GA 196QW UT WOS:000080319900040 ER PT J AU Kawakami, RK Rotenberg, E Escorcia-Aparicio, EJ Choi, HJ Wolfe, JH Smith, NV Qiu, ZQ AF Kawakami, RK Rotenberg, E Escorcia-Aparicio, EJ Choi, HJ Wolfe, JH Smith, NV Qiu, ZQ TI Determination of the magnetic coupling in the Co/Cu/Co(100) system with momentum-resolved quantum well states SO PHYSICAL REVIEW LETTERS LA English DT Article ID SHORT-PERIOD OSCILLATIONS; LAYER THICKNESS; CU FILMS; PHOTOEMISSION; MULTILAYERS; MAGNETORESISTANCE; SUPERLATTICES; CO(100); CU(100); FE/CR AB The relation between the quantum well (QW) states and the oscillatory magnetic coupling in Co/Cu/Co grown on Cu(100) was investigated by angle resolved photoemission spectroscopy, magnetic x-ray linear dichroism, and the surface magneto-optic Kerr effect. The QW states were explained quantitatively using the phase accumulation model, and the derived QW phases at the Cu/Co interface were used to calculate the interlayer coupling. The agreement between this calculation and the experimental result reveals that the phase relation between the long- and short-period couplings is determined by the phase relation of the QW states in k space. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source, Berkeley, CA 94720 USA. RP Kawakami, RK (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Rotenberg, Eli/B-3700-2009; Qiu, Zi Qiang/O-4421-2016 OI Rotenberg, Eli/0000-0002-3979-8844; Qiu, Zi Qiang/0000-0003-0680-0714 NR 23 TC 50 Z9 51 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 17 PY 1999 VL 82 IS 20 BP 4098 EP 4101 DI 10.1103/PhysRevLett.82.4098 PG 4 WC Physics, Multidisciplinary SC Physics GA 196QW UT WOS:000080319900044 ER PT J AU Yang, TJ Gopalan, V Swart, PJ Mohideen, U AF Yang, TJ Gopalan, V Swart, PJ Mohideen, U TI Direct observation of pinning and bowing of a single ferroelectric domain wall SO PHYSICAL REVIEW LETTERS LA English DT Article ID FORCE MICROSCOPY; INTERNAL FIELD; LITAO3; CRYSTALS; VISUALIZATION; ORIGIN AB We have made a direct optical observation of pinning and bowing of a single 180 degrees ferroelectric domain wall under a uniform applied electric field using a collection mode near-field scanning optical microscope. The domain wall is observed to curve between the pinning defects, with a radius of curvature determined by the material parameters and the applied electric field. The change in birefringence with applied field is used to infer the orientation of the internal field at the domain wall. C1 Univ Calif Riverside, Dept Phys, Riverside, CA 92521 USA. Penn State Univ, Dept Mat Sci & Engn, University Pk, PA 16802 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Mohideen, U (reprint author), Univ Calif Riverside, Dept Phys, Riverside, CA 92521 USA. NR 20 TC 162 Z9 165 U1 3 U2 34 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 17 PY 1999 VL 82 IS 20 BP 4106 EP 4109 DI 10.1103/PhysRevLett.82.4106 PG 4 WC Physics, Multidisciplinary SC Physics GA 196QW UT WOS:000080319900046 ER PT J AU de Abajo, FJG Fadley, CS Van Hove, MA AF de Abajo, FJG Fadley, CS Van Hove, MA TI Multiatom resonant photoemission: Theory and systematics SO PHYSICAL REVIEW LETTERS LA English DT Article AB A first-principles calculation of the recently discovered interatomic multiatom resonant photoemission (MARPE) effect is presented. In this phenomenon, core photoelectron intensities are enhanced when the photon energy is tuned to a core-level absorption edge of nonidentical neighboring atoms, thus enabling direct determination of near-neighbor atomic identities. Both the multiatom character of MARPE and retardation effects in the photon and electron interactions in the resonant channel are shown to be crucial. Measured peak-intensity enhancements of 40% in MnO and spectral shapes; similar to the corresponding x-ray absorption profiles are well reproduced by this theory. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Ctr Mixto CSIC UPV EHU, Donostia Int Phys Ctr, Fac Informat, Dept CCIA, San Sebastian, Spain. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. RP de Abajo, FJG (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Van Hove, Michel/A-9862-2008; Garcia de Abajo, Javier/A-6095-2009; DONOSTIA INTERNATIONAL PHYSICS CTR., DIPC/C-3171-2014 OI Van Hove, Michel/0000-0002-8898-6921; Garcia de Abajo, Javier/0000-0002-4970-4565; NR 15 TC 33 Z9 33 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 17 PY 1999 VL 82 IS 20 BP 4126 EP 4129 DI 10.1103/PhysRevLett.82.4126 PG 4 WC Physics, Multidisciplinary SC Physics GA 196QW UT WOS:000080319900051 ER PT J AU Zumbusch, A Holtom, GR Xie, XS AF Zumbusch, A Holtom, GR Xie, XS TI Three-dimensional vibrational imaging by coherent anti-Stokes Raman scattering SO PHYSICAL REVIEW LETTERS LA English DT Article ID FLUORESCENCE MICROSCOPY; CELLS AB A multiphoton microscopy based on coherent anti-Stokes Raman scattering is accomplished with near-infrared ultrashort laser pulses. We demonstrate vibrational imaging of chemical and biological samples with high sensitivity, high spatial resolution, noninvasiveness, and three-dimensional sectioning capability. C1 Pacific NW Lab, William R Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Zumbusch, A (reprint author), Univ Munich, Inst Phys Chem, Butenandtstr 5-13 Haus E, D-81377 Munich, Germany. NR 16 TC 989 Z9 1004 U1 14 U2 181 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 17 PY 1999 VL 82 IS 20 BP 4142 EP 4145 DI 10.1103/PhysRevLett.82.4142 PG 4 WC Physics, Multidisciplinary SC Physics GA 196QW UT WOS:000080319900055 ER PT J AU Harrison, N Singleton, J AF Harrison, N Singleton, J TI Comment on "Frequency mixing of magnetic oscillations: Beyond Falicov-Stachowiak theory" SO PHYSICAL REVIEW LETTERS LA English DT Article ID QUANTUM INTERFERENCE; KAPPA-(BEDT-TTF)(2)CU(NCS)(2); BREAKDOWN C1 Univ Calif Los Alamos Natl Lab, Natl High Magnet Field Lab, Los Alamos, NM 87545 USA. Univ Oxford, Dept Phys, Clarendon Lab, Oxford OX1 3PU, England. RP Harrison, N (reprint author), Univ Calif Los Alamos Natl Lab, Natl High Magnet Field Lab, MS-E536, Los Alamos, NM 87545 USA. NR 5 TC 3 Z9 3 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 17 PY 1999 VL 82 IS 20 BP 4148 EP 4148 DI 10.1103/PhysRevLett.82.4148 PG 1 WC Physics, Multidisciplinary SC Physics GA 196QW UT WOS:000080319900058 ER PT J AU Ostergren, JD Brown, GE Parks, GA Tingle, TN AF Ostergren, JD Brown, GE Parks, GA Tingle, TN TI Quantitative speciation of lead in selected mine tailings from Leadville, CO SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID RAY-ABSORPTION-SPECTROSCOPY; OXIDE-WATER INTERFACES; BOND-VALENCE DETERMINATION; PB(II) SORPTION PRODUCTS; CONTAMINATED SOILS; SURFACE COMPLEXATION; MINING DISTRICT; ARKANSAS RIVER; NATURAL-WATERS; TRACE-METALS AB We have characterized Pb speciation in selected tailings from the Leadville, CO, area using a variety of analytical techniques, including X-ray absorption fine structure (XAFS) spectroscopy. Samples from three locations were analyzed, including two chemically distinct tailings piles located within the city limits [Apache (pyrite-rich, low pH) and Hamms (carbonate-rich, near-neutral pH)] and tailings material deposited as overbank sediments along the Arkansas River approximately 13 km downstream from Leadville (Arkansas River tailings). Extended XAFS (EXAFS) spectra of these multicomponent samples were fit using linear combinations of model compound spectra. In accordance with pH differences among the samples, adsorbed Pb accounts for similar to 50% of total Pb (Pb-T) in fine fractions of the near-neutral pH Hamms tailings, whereas Pb-bearing jarosites account for the majority of Pb-T in the fine fractions of the low pH Apache and Arkansas River tailings. EXAFS analyses following sequential extraction by MgCl2 and EDTA show evidence of significant redistribution (readsorption) of Pb during the MgCl2 extraction and for removal of adsorbed Pb and dissolution of Pb-carbonates during the EDTA extraction. Changes in Pb speciation with water extraction (dissolution of anglesite and precipitation of plumbojarosite) are observed in one sample of Arkansas River tailings. These molecular-scale results show that Pb speciation varies dramatically among environments in the Leadville area and that Pb occurs in a number of phases not amenable to definitive characterization by conventional microanalytical and/or chemical extraction techniques. C1 Stanford Univ, Dept Geog & Environm Sci, Stanford, CA 94305 USA. Stanford Synchrotron Radiat Lab, SLAC, Stanford, CA 94309 USA. Stanford Univ, Ctr Mat Res, Stanford, CA 94305 USA. RP Ostergren, JD (reprint author), Stanford Univ, Dept Geog & Environm Sci, Bldg 320,Room 118, Stanford, CA 94305 USA. NR 60 TC 152 Z9 161 U1 6 U2 41 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD MAY 15 PY 1999 VL 33 IS 10 BP 1627 EP 1636 DI 10.1021/es980660s PG 10 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 196MD UT WOS:000080311400011 ER PT J AU Kladko, K Fulde, P Garanin, DA AF Kladko, K Fulde, P Garanin, DA TI Cumulant expansion for systems with large spins SO EUROPHYSICS LETTERS LA English DT Article AB A method is proposed for obtaining a systematic expansion of thermodynamic functions of spin systems with large spin S in powers of 1/S. It uses the cumulant technique and a coherent-state representation of the partition function Z. The expansion of Z in terms of cumulants yields an effective classical I Hamiltonian with temperature-dependent quantum corrections. For the Heisenberg quantum Hamiltonian, they have a non-Heisenberg form. The effective Hamiltonian can be solved by methods familiar for classical systems. C1 Univ Calif Los Alamos Natl Lab, Condensed Matter Phys Grp, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Div Theoret, Los Alamos, NM 87545 USA. Max Planck Inst Phys Komplexer Syst, D-01187 Dresden, Germany. RP Kladko, K (reprint author), Univ Calif Los Alamos Natl Lab, Condensed Matter Phys Grp, POB 1663,MS-B258, Los Alamos, NM 87545 USA. NR 5 TC 13 Z9 13 U1 0 U2 0 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0295-5075 J9 EUROPHYS LETT JI Europhys. Lett. PD MAY 15 PY 1999 VL 46 IS 4 BP 425 EP 430 DI 10.1209/epl/i1999-00104-y PG 6 WC Physics, Multidisciplinary SC Physics GA 198NR UT WOS:000080431000002 ER PT J AU Pinnaduwage, LA Ding, WX McCorkle, DL Lin, SH Mebel, AM Garscadden, A AF Pinnaduwage, LA Ding, WX McCorkle, DL Lin, SH Mebel, AM Garscadden, A TI Enhanced electron attachment to Rydberg states in molecular hydrogen volume discharges SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID HIGHLY EXCITED MOLECULES; PULSED-FIELD IONIZATION; MULTICUSP ION-SOURCE; LONG-TIME STABILITY; NEGATIVE-ION; NITRIC-OXIDE; ZEKE STATES; H FORMATION; TRIATOMIC HYDROGEN; ENERGY AB We review recent studies on negative ion formation and studies in other areas that are relevant to the role of high-Rydberg states of H-2 and H-3 in hydrogen negative ion sources. Possible mechanisms for the formation of these excited states are discussed, including the formation of long-lived superexcited (core-excited) Rydberg states. Experimental evidence for negative ion formation via electron attachment to core-excited Rydberg states in a glow discharge apparatus is presented. An expression for the dissociative electron attachment rate constant for Rydberg molecules is derived based on electron capture by a Rydberg molecule due to polarization interaction. (C) 1999 American Institute of Physics. [S0021-8979(99)03310-1]. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Acad Sinica, Inst Mol Sci, Taipei 10764, Taiwan. USAF, Wright Patterson AFB, OH 45433 USA. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. RP Pinnaduwage, LA (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA. RI Mebel, Alexander/A-5234-2009 NR 64 TC 23 Z9 23 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 15 PY 1999 VL 85 IS 10 BP 7064 EP 7069 DI 10.1063/1.370513 PG 6 WC Physics, Applied SC Physics GA 193KT UT WOS:000080136000009 ER PT J AU Frase, HN Fultz, B Spooner, S Robertson, JL AF Frase, HN Fultz, B Spooner, S Robertson, JL TI A small angle neutron scattering and Mossbauer spectrometry study of magnetic structures in nanocrystalline Ni3Fe SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID FE; ALLOYS; PALLADIUM; NI; MICROSTRUCTURE; DISTRIBUTIONS AB Results are reported from small angle neutron scattering and Mossbauer spectrometry measurements on nanocrystalline Ni3Fe. The nanocrystalline materials were prepared by mechanical attrition and studied in the as-milled state, after annealing at 265 degrees C to relieve internal stress, and after annealing 600 degrees C to prepare a control sample comprising large crystals. The small angle neutron scattering (SANS) measurements were performed for a range of applied magnetic fields. Small differences were found in how the different samples reached magnetic saturation. From the SANS data obtained at magnetic saturation, we found little difference in the nuclear scattering of the as-milled material and the material annealed at 265 degrees C. Reductions in nuclear scattering and magnetic scattering were observed for the control sample, and this was interpreted as grain growth. The material annealed at 265 degrees C also showed a reduction in magnetic SANS compared to the as-milled material. This was interpreted as an increase in magnetic moments of atoms at the grain boundaries after a low temperature annealing. Both Mossbauer spectroscopy and small angle neutron scattering showed an increase in the grain boundary magnetic moments after the 265 degrees C annealing (0.2 and 0.4 mB/atom, respectively), even though there was little change in the grain boundary atomic density. (C) 1999 American Institute of Physics. [S0021-8979(99)07610-0]. C1 CALTECH, Div Engn & Appl Sci, Pasadena, CA 91125 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Frase, HN (reprint author), CALTECH, Div Engn & Appl Sci, Mail 138-78, Pasadena, CA 91125 USA. NR 33 TC 9 Z9 9 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 15 PY 1999 VL 85 IS 10 BP 7097 EP 7104 DI 10.1063/1.370517 PG 8 WC Physics, Applied SC Physics GA 193KT UT WOS:000080136000013 ER PT J AU Motta, AT Paesano, A Birtcher, RC Bruckmann, ME Teixeira, SR Amaral, L AF Motta, AT Paesano, A Birtcher, RC Bruckmann, ME Teixeira, SR Amaral, L TI Phase formation in Zr-Fe multilayers: Effect of irradiation SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SOLID-STATE REACTION; FE/ZR MULTILAYERS; INTERMETALLIC COMPOUNDS; ELECTRON-IRRADIATION; CORROSION PROPERTIES; MAGNETIC-PROPERTIES; CHEMICAL DIFFUSION; GROWTH-KINETICS; X-RAY; AMORPHIZATION AB We have conducted a detailed in situ study of phase formation in Zr-Fe metallic multilayers using irradiation and thermal annealing. Metallic multilayers with near equiatomic and Fe-rich overall compositions and with repetition thicknesses ranging from 7.4 to 33 nm were either irradiated with 300 keV Kr ions at various temperatures (from 17 to 623 K) or thermally annealed at 773 K while being observed in situ. The kinetics of multilayer reaction were monitored by following the diffraction patterns. For near equiatomic samples, irradiation causes complete amorphization. The dose to amorphization increases in proportion to the square of the wavelength, indicating a process controlled by atomic transport. Amorphization was also achieved by 900 keV electron irradiation at 25 K showing that displacement cascades are not required. The critical dose to amorphization was independent of temperature below room temperature and decreased above room temperature. The activation energy for this second process is 0.17 eV. For the temperature range studied, diffraction from Zr disappears first, indicating that amorphization takes place in the Zr layer by atomic transport of Fe from the Fe layers. These results are consistent with a combination of simple ballistic mixing at low temperature and either simple diffusion or radiation-enhanced diffusion at higher temperatures. Thermal annealing of the equiatomic samples at 773 K produced the same reaction products with slower kinetics. Ion irradiation of Fe-rich samples did not cause complete amorphization and intermetallic compounds Zr3Fe and ZrFe2 were observed in longer wavelength samples. Amorphization of Fe-rich samples was more sluggish, likely because there was competition with formation of other phases. The reaction kinetics were not proportional to square of wavelength for Fe-rich samples, indicating a process that depends on more than atomic transport. Thermal annealing at 773 K of a long wavelength, 57% Fe sample resulted in intermetallic compounds Zr3Fe and ZrFe2 which amorphized during subsequent irradiation. The ease of amorphization of equiatomic samples relative to Fe-rich samples can be explained by a narrower, single minimum free energy curve for the amorphous phase. (C) 1999 American Institute of Physics. [S0021-8979(99)01610-2]. C1 Penn State Univ, Dept Mech & Nucl Engn, University Pk, PA 16802 USA. Univ Estadual Maringa, Inst Fis, Maringa, Parana, Brazil. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60403 USA. Univ Fed Rio Grande Sul, Inst Fis, BR-90000 Porto Alegre, RS, Brazil. RP Motta, AT (reprint author), Penn State Univ, Dept Mech & Nucl Engn, University Pk, PA 16802 USA. RI Teixeira, Sergio/D-5396-2009; OI Ribeiro Teixeira, Sergio/0000-0002-5997-3603 NR 50 TC 4 Z9 4 U1 1 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 15 PY 1999 VL 85 IS 10 BP 7146 EP 7158 DI 10.1063/1.370526 PG 13 WC Physics, Applied SC Physics GA 193KT UT WOS:000080136000022 ER PT J AU Wei, SH Zhang, SB Zunger, A AF Wei, SH Zhang, SB Zunger, A TI Effects of Na on the electrical and structural properties of CuInSe2 SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID CIGS THIN-FILMS; CU(IN,GA)SE-2; SODIUM; PERFORMANCE; SEGREGATION AB We found theoretically that Na has three effects on CuInSe2: (1) If available in stoichiometric quantities, Na will replace Cu, forming a more stable NaInSe2 compound having a larger band gap (higher open-circuit voltage) and a (112)(tetra) morphology. The ensuing alloy NaxCu1-xInSe2 has, however, a positive mixing enthalpy, so NaInSe2 will phase separate, forming precipitates. (2) When available in small quantities, Na will form defect on Cu site and In site. Na on Cu site does not create electric levels in the band gap, while Na on In site creates acceptor levels that are shallower than Cu-In. The formation energy of Na-(InCu) is very exothermic, therefore, the major effect of Na is the elimination of the In-Cu defects and the resulting increase of the effective hole densities. The quenching of In-Cu as well as V-Cu by Na reduces the stability of the (2V(Cu) + In-Cu(2+)), thus suppressing the formation of the "Ordered Defect Compounds.'' (3) Na on the surface of CuInSe2 is known to catalyze the dissociation of O-2 into atomic oxygen that substitutes Se vacancy (shallow donors), converting them into O-Se. We find, however, that O-Se is an (isovalent) deep rather than shallow acceptor. We also find that having removed the donors, O atoms in CuInSe2 form Cu2O and In2O3 compounds, and phase separate, forming precipitates at the surfaces and grain boundaries. Our results are compared with previous models and provide new insights into the defect physics of Na in CIS. (C) 1999 American Institute of Physics. [S0021-8979(99)07010-3]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Wei, SH (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Zunger, Alex/A-6733-2013; Krausnick, Jennifer/D-6291-2013; Zhang, Shengbai/D-4885-2013 OI Zhang, Shengbai/0000-0003-0833-5860 NR 35 TC 176 Z9 180 U1 6 U2 96 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 15 PY 1999 VL 85 IS 10 BP 7214 EP 7218 DI 10.1063/1.370534 PG 5 WC Physics, Applied SC Physics GA 193KT UT WOS:000080136000030 ER PT J AU Xue, ZY Schrader, GL AF Xue, ZY Schrader, GL TI Transient FTIR studies of the reaction pathway for n-butane selective oxidiation over vanadyl pyrophosphate SO JOURNAL OF CATALYSIS LA English DT Article DE n-butane oxidation; VPO catalysts; transient FTIR; adsorbed intermediates ID P-O CATALYSTS; MALEIC-ANHYDRIDE; INSITU FTIR; OXIDATION; ADSORPTION; FURAN; SURFACE; 1,3-BUTADIENE; MECHANISM; OXIDE AB New information has been provided about the reaction pathway for n-butane partial oxidation to maleic anhydride over vanadyl pyrophosphate (VPO) catalysts using FTIR spectroscopy under transient conditions. Adsorption studies of n-butane, 1,3-butadiene, and related oxygenates were performed to gain information about reaction intermediates. n-Butane was found to adsorb on the VPO catalyst to form olefinic species at low temperatures. Unsaturated, noncyclic carbonyl species were determined to be precursors to maleic anhydride. (C) 1999 Academic Press. C1 Iowa State Univ, Dept Chem Engn, Ames, IA 50011 USA. Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA. RP Xue, ZY (reprint author), Iowa State Univ, Dept Chem Engn, Ames, IA 50011 USA. NR 41 TC 19 Z9 20 U1 0 U2 3 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9517 J9 J CATAL JI J. Catal. PD MAY 15 PY 1999 VL 184 IS 1 BP 87 EP 104 DI 10.1006/jcat.1999.2452 PG 18 WC Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA 200VV UT WOS:000080561500010 ER PT J AU Schilke, TC Fisher, IA Bell, AT AF Schilke, TC Fisher, IA Bell, AT TI In situ infrared study of methanol synthesis from CO2/H-2 on titania and zirconia promoted Cu/SiO2 SO JOURNAL OF CATALYSIS LA English DT Article ID SUPPORTED COPPER-CATALYSTS; CARBON-DIOXIDE; AEROGEL CATALYSTS; ADSORPTION; SURFACE; OXIDE; DECOMPOSITION; HYDROGENATION; MECHANISM; MONOXIDE AB In situ infrared studies of methanol synthesis from H-2/CO2 have been conducted over Cu/SiO2 promoted with ZrO2, TiO2, and a mixture of TiO2/ZrO2, with the aim of establishing the means by which the added oxide influences the activity of the catalyst for methanol synthesis. While ZrO2 and TiO2 individually enhance the methanol synthesis activity of Cu/SiO2, a significantly greater enhancement is achieved by addition of both oxides simultaneously. In the absence of oxide addition, infrared spectra taken under reaction conditions suggest that methanol synthesis from CO2 takes place on the surface of Cu exclusively. When ZrO2 is added to the catalyst, there is strong evidence for methanol synthesis on the surface of both Cu and ZrO2. Catalysis on the surface of ZrO2 occurs as a consequence of CO2 adsorption to form b-HCO3-Zr, which then undergoes progressive hydrogenation to form methanol. The required atomic hydrogen is supplied from the surface of Cu particles by spillover. When TiO2 is added there is no evidence for catalysis occurring on the oxide surface, but strong evidence for an enhancement in the level of reaction occurring on the surface of Cu. The observed increase in the rate of methanol synthesis is attributed to a reconstruction of the Cu particles to expose the (100) surface, which have been demonstrated to be significantly more active than the (110) or (111) surfaces. The infrared spectra observed when a mixture of ZrO2 and TiO2 is added to Cu/SiO2 resembles a composite of the spectra observed upon addition of the individual oxides, and hence, the enhanced rate of methanol synthesis is ascribed to the combined effects of ZrO2 and TiO2. (C) 1999 Academic Press. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. RP Schilke, TC (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. NR 51 TC 38 Z9 38 U1 2 U2 38 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9517 J9 J CATAL JI J. Catal. PD MAY 15 PY 1999 VL 184 IS 1 BP 144 EP 156 DI 10.1006/jcat.1999.2434 PG 13 WC Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA 200VV UT WOS:000080561500015 ER PT J AU Nielsen, IMB Seidl, ET Janssen, CL AF Nielsen, IMB Seidl, ET Janssen, CL TI Accurate structures and binding energies for small water clusters: The water trimer SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID CORRELATED MOLECULAR CALCULATIONS; GAUSSIAN-BASIS SETS; AB-INITIO; WAVE-FUNCTIONS; IMPLEMENTATION; ALGORITHM; BENCHMARK; (H2O)(N); SURFACE; MODELS AB The global minimum on the water trimer potential energy surface has been investigated by means of second-order Moller-Plesset (MP2) perturbation theory employing the series of correlation-consistent basis sets aug-cc-pVXZ (X = D, T, Q, 5, 6), the largest of which contains 1329 basis functions. Definitive predictions are made for the binding energy and equilibrium structure, and improved values are presented for the harmonic vibrational frequencies. A value of 15.82+/-0.05 kcal mol(-1) is advanced for the infinite basis set frozen core MP2 binding energy, obtained by extrapolation of MP2 correlation energies computed at the aug-cc-pVQZ MP2 geometry. Inclusion of core correlation, using the aug-cc-pCV5Z basis set, has been found to increase the binding energy by 0.08 kcal mol(-1), and after consideration of core correlation and higher-order correlation effects, the classical binding energy for the water trimer is estimated to be 15.9+/-0.2 kcal mol(-1). A zero-point vibrational correction of -5.43 kcal mol(-1) has been computed from aug-cc-pVTZ MP2 harmonic vibrational frequencies. The accuracy of different computational schemes for obtaining the binding energies of the water dimer and trimer has been investigated, and computationally feasible methods are suggested for obtaining accurate structures and binding energies for larger water clusters. (C) 1999 American Institute of Physics. [S0021-9606(99)30519-5]. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Nielsen, IMB (reprint author), Sandia Natl Labs, MS 9214,POB 969, Livermore, CA 94551 USA. NR 38 TC 99 Z9 103 U1 0 U2 14 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 15 PY 1999 VL 110 IS 19 BP 9435 EP 9442 DI 10.1063/1.478908 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 193TV UT WOS:000080154000012 ER PT J AU Lenzer, T Yourshaw, I Furlanetto, MR Reiser, G Neumark, DM AF Lenzer, T Yourshaw, I Furlanetto, MR Reiser, G Neumark, DM TI Zero electron kinetic energy spectroscopy of the ArCl- anion SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID THRESHOLD PHOTODETACHMENT SPECTROSCOPY; DYNAMIC MULTIPOLE POLARIZABILITIES; CLOSED-SHELL ATOMS; GAS-HALIDE-SYSTEMS; ION-RARE-GAS; INTERACTION POTENTIALS; DISPERSION COEFFICIENTS; VIBRATIONAL SPECTROSCOPY; TDMP2 CALCULATION; HALOGEN ANIONS AB Zero electron kinetic energy (ZEKE) spectroscopy has been utilized to study the (ArCl-)-Ar-40-Cl-35 anion and the X1/2, I3/2 and II1/2 electronic states of neutral ArCl. Well-resolved progressions in the low-frequency vibrations of the anion and the neutral complexes are observed in the ZEKE spectra. From our spectroscopic data we construct model potential functions for the anion and three neutral states. This yields refined values for the neutral state splittings and the first accurate experimental ArCl- anion potential. Absolute uncertainties for R-m and epsilon in all potentials are estimated to be +/-0.08 Angstrom and +/-0.6 meV, respectively. (C) 1999 American Institute of Physics. [S0021-9606(99)01819-X]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Lenzer, T (reprint author), Univ Gottingen, Inst Phys Chem, Tammannstr 6, D-37077 Gottingen, Germany. RI Neumark, Daniel/B-9551-2009 OI Neumark, Daniel/0000-0002-3762-9473 NR 50 TC 58 Z9 59 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 15 PY 1999 VL 110 IS 19 BP 9578 EP 9586 DI 10.1063/1.478923 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 193TV UT WOS:000080154000029 ER PT J AU Vogel, SN Johnson, D Perera, PY Medvedev, A Lariviere, L Qureshi, ST Malo, D AF Vogel, SN Johnson, D Perera, PY Medvedev, A Lariviere, L Qureshi, ST Malo, D TI Cutting edge: Functional characterization of the effect of the C3H/HeJ defect in mice that lack an Lps(n) gene: In vivo evidence for a dominant negative mutation SO JOURNAL OF IMMUNOLOGY LA English DT Article ID TYROSINASE-RELATED PROTEIN; BROWN (B)-LOCUS REGION; HIGH-RESOLUTION MAP; MOUSE CHROMOSOME-4; BACTERIAL LIPOPOLYSACCHARIDES; MOLECULAR-GENETICS; RESPONSES; UNRESPONSIVENESS; DELETIONS; LOCUS AB A point mutation in the Tlr4 gene, which encodes Toll-like receptor 4, has recently been proposed to underlie LPS hyporesponsiveness in C3H/HeJ mice (Lps(d)), The data presented herein demonstrate that F-1 progeny from crosses between mice that carry a similar to 9-cM deletion of chromosome 4 (including deletion of Lps(Tlr4)) and C3H/HeJ mice (i.e., Lps(0) x Lps(d) F-1 mice) exhibit a pattern of LPS sensitivity, measured by TNF activity, that is indistinguishable from that exhibited by Lps(n) x Lps(d) F-1 progeny and whose average response is "intermediate" to parental responses. Thus, these data provide clear functional support for the hypothesis that the C3H/HeJ defect exerts a dominant negative effect on LPS sensitivity; however, expression of a normal Toll-like receptor 4 molecule is apparently not required. C1 Uniformed Serv Univ Hlth Sci, Dept Microbiol & Immunol, Bethesda, MD 20814 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. McGill Univ, Dept Med, Montreal, PQ, Canada. McGill Univ, Dept Human Genet, Montreal, PQ, Canada. RP Vogel, SN (reprint author), Uniformed Serv Univ Hlth Sci, Dept Microbiol & Immunol, 4301 Jones Bridge Rd,B103, Bethesda, MD 20814 USA. FU NIAID NIH HHS [AI-18797] NR 34 TC 114 Z9 114 U1 0 U2 0 PU AMER ASSOC IMMUNOLOGISTS PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0022-1767 J9 J IMMUNOL JI J. Immunol. PD MAY 15 PY 1999 VL 162 IS 10 BP 5666 EP 5670 PG 5 WC Immunology SC Immunology GA 195FP UT WOS:000080240200003 PM 10229796 ER PT J AU Suh, S Hoffman, DM Atagi, LM Smith, DC AF Suh, S Hoffman, DM Atagi, LM Smith, DC TI A new metal-organic precursor for the low-temperature atmospheric pressure chemical vapor deposition of zinc oxide films SO JOURNAL OF MATERIALS SCIENCE LETTERS LA English DT Article ID ZNO THIN-FILMS; DIETHYL ZINC; TRANSPARENT; ACETATE; GROWTH; MOCVD; WATER C1 Univ Houston, Dept Chem, Houston, TX 77204 USA. Mat Res Sci & Engn Ctr, Houston, TX 77204 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Suh, S (reprint author), Univ Houston, Dept Chem, Univ Pk, Houston, TX 77204 USA. NR 25 TC 13 Z9 15 U1 1 U2 5 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0261-8028 J9 J MATER SCI LETT JI J. Mater. Sci. Lett. PD MAY 15 PY 1999 VL 18 IS 10 BP 789 EP 791 DI 10.1023/A:1006689017053 PG 3 WC Materials Science, Multidisciplinary SC Materials Science GA 212UZ UT WOS:000081237100012 ER PT J AU Paulik, SW Baskaran, S Armstrong, TR AF Paulik, SW Baskaran, S Armstrong, TR TI Mechanical properties of calcium-substituted yttrium chromite SO JOURNAL OF MATERIALS SCIENCE LETTERS LA English DT Article ID LANTHANUM CHROMITE; TOUGHNESS C1 Pacific NW Lab, Dept Chem & Mat Sci, Richland, WA 99352 USA. RP Paulik, SW (reprint author), Pacific NW Lab, Dept Chem & Mat Sci, POB 999, Richland, WA 99352 USA. NR 13 TC 11 Z9 12 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0261-8028 J9 J MATER SCI LETT JI J. Mater. Sci. Lett. PD MAY 15 PY 1999 VL 18 IS 10 BP 819 EP 822 DI 10.1023/A:1006605620688 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA 212UZ UT WOS:000081237100020 ER PT J AU Nolan, DS Farrell, BF AF Nolan, DS Farrell, BF TI Generalized stability analyses of asymmetric disturbances in one- and two-celled vortices maintained by radial inflow SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID TORNADO-LIKE VORTICES; BAROTROPIC VORTEX; OPTIMAL EXCITATION; ROSSBY-WAVES; SPIRAL BANDS; SHEAR-FLOW; MOTION; PERTURBATIONS; INSTABILITY; SIMULATION AB The dynamics of both transient and exponentially growing disturbances in two-dimensional vortices that are maintained by the radial inflow of a fixed cylindrical deformation held are investigated. Such deformation fields are chosen so that both one-celled and two-celled vortices may be studied. The linearized evolution of asymmetric perturbations is expressed in the form of a linear dynamical system dx/dt = Ax. The shear of the mean flow results in a nonnormal dynamical operator A, allowing for the transient growth of perturbations even when all the modes of the operator are decaying. It is found that one-celled vortices are stable to asymmetric perturbations of all azimuthal wavenumbers, whereas two-celled vortices can have low-wavenumber instabilities. In all cases, generalized stability analysis of the dynamical operator identifies the perturbations that grow the fastest, both instantaneously and over a finite period of time. While the unstable modal perturbations necessarily convert mean-flow vorticity to perturbation vorticity, the perturbations with the fastest instantaneous growth rate use the deformation of the mean flow to rearrange their vorticity fields into configurations with higher kinetic energy. Also found are perturbations that use a hybrid of these two mechanisms to achieve substantial energy growth over finite time periods. Inclusion of the dynamical effects of radial inflow-vorticity advection and vorticity stretching-is found to be extremely important in assessing the potential for transient growth and instability in these vortices. In the two-celled vortex, neglecting these terms destabilizes the vortex for azimuthal wavenumbers one and two. In the one-celled vortex, neglect of the radial inflow terms results in an overestimation of transient growth for all wavenumbers, and it is also found that for high wavenumbers the maximum transient growth decreases as the strength of the radial inflow increases. The effects of these perturbations through eddy flux divergences on the mean flow are also examined. In the one-celled vortex it is found that for all wavenumbers greater than one the net effect of most perturbations, regardless of their initial configuration. is to increase the kinetic energy of the mean Row. As these perturbations are sheared over they cause upgradient eddy momentum fluxes, thereby transferring their kinetic energy to the mean flow and intensifying the vortex. However, for wavenumber one in the one-celled vortex, and all wavenumbers in the two-celled vortex, it was found that nearly all perturbations have the net effect of decreasing the kinetic energy of the mean how. In these cases, the kinetic energy of the perturbations accumulates in nearly neutral or unstable modal structures, so that energy acquired from the mean flow is not returned to the mean flow but instead is lost through dissipation. C1 Lawrence Berkeley Natl Lab, Dept Math, Berkeley, CA USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. RP Nolan, DS (reprint author), Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. NR 48 TC 35 Z9 35 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAY 15 PY 1999 VL 56 IS 10 BP 1282 EP 1307 DI 10.1175/1520-0469(1999)056<1282:GSAOAD>2.0.CO;2 PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 194YM UT WOS:000080222400002 ER PT J AU Yang, CR Yeh, SY Leskov, K Odegaard, E Hsu, HL Chang, CS Kinsella, TJ Chen, DJ Boothman, DA AF Yang, CR Yeh, SY Leskov, K Odegaard, E Hsu, HL Chang, CS Kinsella, TJ Chen, DJ Boothman, DA TI Isolation of Ku70-binding proteins (KUBs) SO NUCLEIC ACIDS RESEARCH LA English DT Article ID ATAXIA-TELANGIECTASIA GENE; STRAND BREAK REPAIR; APOLIPOPROTEIN-J; 2-HYBRID SYSTEM; VENTRAL PROSTATE; MESSENGER-RNA; CANCER CELLS; DNA-DAMAGE; KINASE; EXPRESSION AB DNA-dependent protein kinase (DNA-PK) plays a critical role in resealing DNA double-stand breaks by non-homologous end joining. Aside from DNA-PK, XRCC4 and DNA ligase IV, other proteins which play a role(s) in this repair pathway remain unknown; DNA-PK contains a catalytic subunit (DNA-PKcs) and a DNA binding subunit (Ku70 and Ku80), We isolated Ku70-binding proteins (KUB1-KUB4) using yeast two-hybrid analyses. Sequence analyses revealed KUB1 to be apolipoprotein J (apoJ), also known as X-ray-inducible transcript 8 (XIP8), testosterone-repressed prostate message-2 (TRPM-5) and clusterin. KUB2 is Ku80, KUB3 and KUB4 are unknown, >10 kb transcripts. Interactions of apoJ/XIP8 or KUB3 with Ku70 were confirmed by co-immunoprecipitation analyses in MCF-7:WS8 breast cancer or IMR-90 normal lung fibroblast cells, respectively. The interaction of apoJ/XIP8 with Ku70 was confirmed by far-western analyses, Stable over-expression of full-length apoJ/XIP8 in MCF-7:WS8 caused decreased Ku70/Ku80 DNA end binding that was restored by apoJ/XIP8 monoclonal antibodies. The role of apoJ/XIP8 in ionizing radiation resistance/sensitivity is under investigation. C1 Case Western Reserve Univ, Dept Radiat Oncol, Cleveland, OH 44106 USA. Case Western Reserve Univ, Dept Pharmacol, Cleveland, OH 44106 USA. Case Western Reserve Univ, Ireland Canc Ctr, Lab Mol Stress Responses, Cleveland, OH 44106 USA. Univ Rochester, Med Ctr, Dept Pathol & Lab Med, Rochester, NY 14642 USA. Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. RP Boothman, DA (reprint author), Case Western Reserve Univ, Dept Radiat Oncol, BRB-326 E,10900 Euclid Ave, Cleveland, OH 44106 USA. RI Hsu, Hsin-Ling/E-3672-2010 FU NCI NIH HHS [CA-ES78530, CA50519, R01 CA139217, CA-50595] NR 58 TC 77 Z9 86 U1 0 U2 1 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0305-1048 J9 NUCLEIC ACIDS RES JI Nucleic Acids Res. PD MAY 15 PY 1999 VL 27 IS 10 BP 2165 EP 2174 DI 10.1093/nar/27.10.2165 PG 10 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 198NY UT WOS:000080431800013 PM 10219089 ER PT J AU Goldberg, L Koplow, JP Kliner, DAV AF Goldberg, L Koplow, JP Kliner, DAV TI Highly efficient 4-W Yb-doped fiber amplifier pumped by a broad-stripe laser diode SO OPTICS LETTERS LA English DT Article AB A Yb-doped double-cladding fiber amplifier is v-groove side pumped by a 100-mu m-wide, broad-stripe, 975-nm laser diode. The amplifier exhibits, separately, 39% electrical-to-optical conversion efficiency, 89% internal optical-to-optical conversion efficiency, 4-W output power at 1060 nm, and a small-signal gain of 53 dB. (C) 1999 Optical Society of America OCIS codes: 060.2320, 140.3510, 140.4480. C1 USN, Res Lab, Div Opt Sci, Washington, DC 20375 USA. Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. RP Goldberg, L (reprint author), USN, Res Lab, Div Opt Sci, Washington, DC 20375 USA. NR 11 TC 75 Z9 80 U1 0 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD MAY 15 PY 1999 VL 24 IS 10 BP 673 EP 675 DI 10.1364/OL.24.000673 PG 3 WC Optics SC Optics GA 197DH UT WOS:000080349000013 PM 18073819 ER PT J AU Wolverton, C Zunger, A AF Wolverton, C Zunger, A TI Magnetic destabilization of Ni7Al SO PHYSICAL REVIEW B LA English DT Article ID ANGLE-RESOLVED PHOTOEMISSION; INTERFACIAL FREE-ENERGIES; PHASE-STABILITY; BAND-STRUCTURE; SPECIAL POINTS; DENSITY; TRANSITION; ALLOYS; NI3AL; NI AB Previously unknown cubic ordered Ni7Al and Cu7Pt compounds have recently been theoretically predicted to be stable phases in the Ni-Al and Cu-Pt systems. While Cu7Pt was subsequently synthesized and identified, NI,AI remains experimentally unobserved. Using first-principles total energy calculations, we reinvestigate the stability of this Ni7Al compound. We find the stability of this compound to be qualitatively effected by spin polarization, ignored in previous calculations. The effect of ferromagnetism is to Stabilize the two-phase mixture of Ni+Ni3Al relative to the Ni7Al compound such that the latter is stable in nonmagnetic calculations, but unstable when spin polarization is taken into account. This reversal of relative stabilities of Ni7Al and Ni+Ni3Al with magnetism also has a dramatic effect on the calculated Ni3Al/Ni interfacial energy sigma and spin-polarized calculations lead to a positive value of a, which is in qualitative agreement with values obtained from precipitation experiments. [S0163-1829(99)05319-9]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Wolverton, C (reprint author), Ford Motor Co, MD 3028-SRL,POB 2053, Dearborn, MI 48121 USA. RI Wolverton, Christopher/B-7542-2009; Zunger, Alex/A-6733-2013 NR 32 TC 10 Z9 10 U1 0 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1999 VL 59 IS 19 BP 12165 EP 12168 DI 10.1103/PhysRevB.59.12165 PG 4 WC Physics, Condensed Matter SC Physics GA 200ZU UT WOS:000080570800001 ER PT J AU Vuillemin, JJ Harrison, N Goodrich, RG AF Vuillemin, JJ Harrison, N Goodrich, RG TI High-field de Haas-van Alphen measurements in Pd SO PHYSICAL REVIEW B LA English DT Article AB The de Haas-van Alphen (dHvA) effect in 99.999% pure palladium has been observed in pulsed fields up to 60 T directed along [100]. We report a dHvA frequency of 73.5 kT with a cyclotron effective mass = 12.5 m(0). Such a frequency is not reported previously but is predicted by band theory for the open hole sheet of the Fermi surface. We also observe strong harmonic content near 50 T for the electron sheet and this is interpreted in terms of a field-dependent g factor. [S0163-1829(99)05707-0]. C1 Univ Arizona, Dept Phys, Tucson, AZ 85721 USA. Univ Calif Los Alamos Natl Lab, Natl High Magnet Field Lab, Los Alamos, NM 87545 USA. Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA. RP Vuillemin, JJ (reprint author), Univ Arizona, Dept Phys, Tucson, AZ 85721 USA. NR 9 TC 2 Z9 2 U1 1 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1999 VL 59 IS 19 BP 12177 EP 12179 DI 10.1103/PhysRevB.59.12177 PG 3 WC Physics, Condensed Matter SC Physics GA 200ZU UT WOS:000080570800004 ER PT J AU Cho, JH Zhang, ZY Lee, SH Kang, MH AF Cho, JH Zhang, ZY Lee, SH Kang, MH TI Geometry and core-level shifts of As on GaAs(110) SO PHYSICAL REVIEW B LA English DT Article ID SURFACE; PHOTOEMISSION; SB/GAAS(110); ADSORPTION AB The atomic structure of the As-covered GaAs(110) surface in one-monolayer coverage is studied using the pseudopotential density-functional theory. We compare the adsorption geometry of As/GaAs(110) with that of the well-studied isoelectronic Sb/GaAs(110) system and discuss the large difference in the desorption temperature found in both systems, based on the calculated adsorption energies. In addition, we calculate the As 3d and Ga 3d core-level shifts at As/GaAs(110) using: initial-state theory. Our calculations not only produce well the surface components resolved in a recent photoemission experiment, but predict an additional surface core level for the substrate As atom bonded to the adsorbed As atom. [S0163-1829(99)02219-5]. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Pohang Univ Sci & Technol, Dept Phys, Pohang 790784, South Korea. RP Natl Renewable Energy Lab, Solid State Theory Grp, Golden, CO 80401 USA. RI Lee, Sung-Hoon/A-9582-2011; Cho, Jun-Hyung/R-7256-2016 OI Lee, Sung-Hoon/0000-0002-8553-8007; Cho, Jun-Hyung/0000-0002-1785-1835 NR 18 TC 6 Z9 6 U1 1 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1999 VL 59 IS 19 BP 12200 EP 12203 DI 10.1103/PhysRevB.59.12200 PG 4 WC Physics, Condensed Matter SC Physics GA 200ZU UT WOS:000080570800010 ER PT J AU Lee, DH Misra, A Walter, KC Nastasi, M AF Lee, DH Misra, A Walter, KC Nastasi, M TI Inhomogeneous structure in hydrogenated tetrahedral amorphous carbon thin films SO PHYSICAL REVIEW B LA English DT Article ID DIAMOND-LIKE CARBON; CROSS-SECTIONAL STRUCTURE; GROWTH; PLASMA; MODEL AB The structure of hydrogenated tetrahedral amorphous carbon (ta-C:H) thin film was investigated by observing variations in film stress and mass density as a function of the film thickness. Cross-sectional transmission electron microscopy clearly shows an inhomogeneous microstructure that includes a region near the substrate/film interface with a higher density than the remainder of the film. It is postulated that surface charge accumulation of the insulating coating reduces the energy of the incoming ions. Lower-energy ion bombardment results in a ta-C:H film with both reduced stress and mass density. [S0163-1829(99)05520-4]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Lee, DH (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Misra, Amit/H-1087-2012 NR 14 TC 4 Z9 4 U1 1 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1999 VL 59 IS 19 BP 12283 EP 12285 DI 10.1103/PhysRevB.59.12283 PG 3 WC Physics, Condensed Matter SC Physics GA 200ZU UT WOS:000080570800031 ER PT J AU Pask, JE Klein, BM Fong, CY Sterne, PA AF Pask, JE Klein, BM Fong, CY Sterne, PA TI Real-space local polynomial basis for solid-state electronic-structure calculations: A finite-element approach SO PHYSICAL REVIEW B LA English DT Article ID MOLECULAR-DYNAMICS; ADAPTIVE-COORDINATE; PSEUDOPOTENTIALS; DIFFERENCE; WAVELETS AB We present an approach to solid-state electronic-structure calculations based on the finite-element method. In this method, the basis functions are strictly local, piecewise polynomials. Because the basis is composed of polynomials, the method is completely general and its convergence can be controlled systematically. Because the basis functions are strictly local in real space, the method allows for variable resolution in real space; produces sparse, structured matrices, enabling the effective use of iterative solution methods; and is well suited to parallel implementation. The method thus combines the significant advantages of both real-space-grid and basis-oriented approaches and so promises to be particularly well suited for large, accurate nb initio calculations. We develop the theory of our approach in detail, discuss advantages and disadvantages, and report initial results, including electronic band structures and details of the convergence of the method. [S0163-1829(99)03515-8]. C1 Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Pask, JE (reprint author), Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. NR 40 TC 68 Z9 69 U1 3 U2 8 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1999 VL 59 IS 19 BP 12352 EP 12358 DI 10.1103/PhysRevB.59.12352 PG 7 WC Physics, Condensed Matter SC Physics GA 200ZU UT WOS:000080570800042 ER PT J AU Zhuang, X Miranda, PB Kim, D Shen, YR AF Zhuang, X Miranda, PB Kim, D Shen, YR TI Mapping molecular orientation and conformation at interfaces by surface nonlinear optics SO PHYSICAL REVIEW B LA English DT Article ID AIR-WATER-INTERFACE; FREQUENCY VIBRATIONAL SPECTROSCOPY; 2ND HARMONIC-GENERATION; SUM-FREQUENCY; 2ND-HARMONIC GENERATION; PHASE-TRANSITION; MONOLAYER; REFLECTION; ANGLE; CHAIN AB Second-order nonlinear optics can be used to quantitatively determine the orientation of chemical bonds or submoieties of a fairly complicated molecule at an interface, and therefore completely map out its orientation and conformation. As a specific example, we have studied pentyl-cyanoterphenyl molecules at the air-water interface. We have measured the orientation of all three parts of the molecule (cyano head group, terphenyl ring, and pentyl chain) by optical second-harmonic generation and infrared-visible sum-frequency generation. A quantitatively consistent picture of the molecular configuration has been obtained. The technique can be applied to situations where other methods would fail (e.g., the surface of neat liquids or buried interfaces). [S0163-1829(99)04119-3]. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Shen, YR (reprint author), Stanford Univ, Dept Phys, Stanford, CA 94305 USA. EM shenyr@socrates.berkeley.edu RI Miranda, Paulo/C-5933-2012; Kim, Doseok/J-8776-2013 OI Miranda, Paulo/0000-0002-2890-0268; NR 53 TC 546 Z9 547 U1 16 U2 133 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1999 VL 59 IS 19 BP 12632 EP 12640 DI 10.1103/PhysRevB.59.12632 PG 9 WC Physics, Condensed Matter SC Physics GA 200ZU UT WOS:000080570800073 ER PT J AU Sigalas, MM Soukoulis, CM Chan, CT Biswas, R Ho, KM AF Sigalas, MM Soukoulis, CM Chan, CT Biswas, R Ho, KM TI Effect of disorder on photonic band gaps SO PHYSICAL REVIEW B LA English DT Article ID PERIODIC DIELECTRIC STRUCTURES; WAVE-PROPAGATION; 2 DIMENSIONS; LOCALIZATION AB We study the transmission of electromagnetic waves propagating in three-dimensional disordered photonic crystals that are periodic on the average with a diamond symmetry. The transmission has been calculated using the transfer matrix method. We study two different geometries for the scatterers: spheres and rods connecting nearest neighbors. We find that the gaps of the periodic structure survive to a higher amount of disorder in the rods' case than in the spheres' case. We argue that this is due to the connectivity of the rod structure that exists for any amount of disorder. [S0163-1829(99)04120-X]. C1 Iowa State Univ, Ames Lab, Dept Phys & Astron, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ctr Microelect Res, Ames, IA 50011 USA. RP Sigalas, MM (reprint author), Iowa State Univ, Ames Lab, Dept Phys & Astron, Ames, IA 50011 USA. RI Soukoulis, Costas/A-5295-2008 NR 20 TC 77 Z9 80 U1 0 U2 10 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1999 VL 59 IS 20 BP 12767 EP 12770 DI 10.1103/PhysRevB.59.12767 PG 4 WC Physics, Condensed Matter SC Physics GA 200ZW UT WOS:000080571000012 ER PT J AU Carlson, J Gubernatis, JE Ortiz, G Zhang, SW AF Carlson, J Gubernatis, JE Ortiz, G Zhang, SW TI Issues and observations on applications of the constrained-path Monte Carlo method to many-fermion systems SO PHYSICAL REVIEW B LA English DT Article ID 2-DIMENSIONAL HUBBARD-MODEL; PAIRING CORRELATIONS; LATTICE FERMIONS; FIELD; SIMULATION; ENERGY AB We report several important observations that underscore the distinctions between the constrained-path Monte Carlo method and the continuum and lattice versions of the fixed-node method. The main distinctions stern from the differences in the state space in which the random walk occurs and in the manner in which the random walkers are constrained. One consequence is that in the constrained-path method the so-called mixed estimator for the energy is not an upper bound to the exact energy, as previously claimed. Several ways of producing an energy upper bound are given, and relevant methodological aspects are illustrated with simple examples. [S0163-1829(99)06319-5]. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Coll William & Mary, Dept Phys, Williamsburg, VA 23187 USA. Coll William & Mary, Dept Appl Sci, Williamsburg, VA 23187 USA. RP Carlson, J (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 25 TC 41 Z9 41 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1999 VL 59 IS 20 BP 12788 EP 12798 DI 10.1103/PhysRevB.59.12788 PG 11 WC Physics, Condensed Matter SC Physics GA 200ZW UT WOS:000080571000015 ER PT J AU Kurmaev, EZ Korotin, MA Galakhov, VR Finkelstein, LD Zabolotzky, EI Efremova, NN Lobachevskaya, NI Stadler, S Ederer, DL Callcott, TA Zhou, L Moewes, A Bartkowski, S Neumann, M Matsuno, J Mizokawa, T Fujimori, A Mitchell, J AF Kurmaev, EZ Korotin, MA Galakhov, VR Finkelstein, LD Zabolotzky, EI Efremova, NN Lobachevskaya, NI Stadler, S Ederer, DL Callcott, TA Zhou, L Moewes, A Bartkowski, S Neumann, M Matsuno, J Mizokawa, T Fujimori, A Mitchell, J TI X-ray emission and photoelectron spectra of Pr0.5Sr0.5MnO3 SO PHYSICAL REVIEW B LA English DT Article ID METAL-INSULATOR-TRANSITION; MAGNETIC-FIELD; FLUORESCENCE SPECTROSCOPY; ELECTRONIC-STRUCTURE; NEUTRON-DIFFRACTION; PR1-XCAXMNO3; LA1-XSRXMNO3; PEROVSKITES; MAGNETORESISTANCE; PR1-XSRXMNO3 AB The results of measurements of x-ray photoelectron (XPS), x-ray emission (XES), and x-ray absorption spectra and local spin-density approximation band structure (LSDA) calculations of Pr0.5Sr0.5MnO3 are resented. The excitation energy dependence of Mn L-2,L-3 and O K alpha x-ray emission spectra of Pr0.5Sr0.5MnO3 is measured using tunable synchrotron radiation. The XES measurements yielded no photon energy dependence for the O K alpha spectra, but the Mn L-2,L-3 spectra yielded inelastic scattering losses of 2 and 6 eV, corresponding to features in the structure of the occupied part of the valence band. Comparing XPS and XES measurements with LSDA band-structure calculations, one concludes that the electronic structure of the compound consists mainly of Mn 3d and O 2p states. States of 3d character localized at the Mn site predominate near the top of the valence band (VB). Some differences in the Mn 3d distribution in this part of the XPS valence band and Mn L-3 XES with d symmetry due to spin-selection rules that govern the Mn L-3 XES. In addition, the Mn 3d states distribution is hybridized with the O 2p part of the VB. Mn L-3 XES spectra were determined relative to the Fermi energy by assuming normal x-ray emission begins from the lowest level of the p(5)d(n+1)L intermediate state (which is the Mn 2p ionizatation threshold). From the local spin-density approximation, the orbital character of the Mn 3d electrons can be assigned eg symmetry at the top of the valence band T-2g in the central part of the VB, and equal contributions of e(g) and T-2g states at the bottom of the valence band. [S0163-1829(99)00620-7]. C1 Russian Acad Sci, Inst Met Phys, Ural Div, Ekaterinburg 620219, Russia. Russian Acad Sci, Inst Solid State Chem, Ekaterinburg 620219, Russia. Tulane Univ, Dept Phys, New Orleans, LA 70118 USA. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. Louisiana State Univ, Ctr Adv Microstruct & Devices, Baton Rouge, LA 70806 USA. Univ Osnabruck, Fachbereich Phys, D-49069 Osnabruck, Germany. Univ Tokyo, Dept Phys, Bunkyo Ku, Tokyo 113, Japan. Argonne Natl Lab, Argonne, IL 60439 USA. RP Kurmaev, EZ (reprint author), Russian Acad Sci, Inst Met Phys, Ural Div, GSP-170, Ekaterinburg 620219, Russia. RI Korotin, Michael/J-3252-2013; Nechkina, Larisa/J-5974-2013; Kurmaev, Ernst/J-4254-2013; Mizokawa, Takashi/E-3302-2015; Galakhov, Vadim/J-6030-2013; Matsuno, Jobu/C-1737-2008 OI Korotin, Michael/0000-0002-9603-8374; Nechkina, Larisa/0000-0002-6268-7958; Kurmaev, Ernst/0000-0003-4625-4930; Mizokawa, Takashi/0000-0002-7682-2348; Galakhov, Vadim/0000-0002-1642-7362; Matsuno, Jobu/0000-0002-3018-8548 NR 32 TC 27 Z9 27 U1 0 U2 8 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1999 VL 59 IS 20 BP 12799 EP 12806 DI 10.1103/PhysRevB.59.12799 PG 8 WC Physics, Condensed Matter SC Physics GA 200ZW UT WOS:000080571000016 ER PT J AU Crandles, DA Nicholas, B Dreher, C Homes, CC McConnell, AW Clayman, BP Gong, WH Greedan, JE AF Crandles, DA Nicholas, B Dreher, C Homes, CC McConnell, AW Clayman, BP Gong, WH Greedan, JE TI Optical properties of highly reduced SrTiO3-x SO PHYSICAL REVIEW B LA English DT Article ID ELECTRONIC-STRUCTURE; SINGLE-CRYSTALS; DOPED SRTIO3; CONDUCTIVITY; REFLECTANCE; TRANSPORT; GROWTH; PLANE; METAL AB The reflectance of highly reduced SrTiO3-x has been studied in samples where the carrier concentration-or oxygen-vacancy density - varies from about 10(18) to 10(21) cm(-3). Several phonon modes are strongly influenced by oxygen-vacancy density. Oxygen reduction induces a mid-infrared band whose oscillator strength scales with carrier density. In highly reduced samples, a weakly localized plasmon mode develops. [S0163-1829(99)10919-6]. C1 Franklin & Marshall Coll, Dept Phys & Astron, Lancaster, PA 17604 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Simon Fraser Univ, Dept Phys, Burnaby, BC V5A 1S6, Canada. McMaster Univ, Dept Chem, Hamilton, ON L2S 4M1, Canada. McMaster Univ, Brockhouse Inst Mat Res, Hamilton, ON L2S 4M1, Canada. RP Crandles, DA (reprint author), Franklin & Marshall Coll, Dept Phys & Astron, Lancaster, PA 17604 USA. NR 23 TC 52 Z9 52 U1 3 U2 31 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1999 VL 59 IS 20 BP 12842 EP 12846 DI 10.1103/PhysRevB.59.12842 PG 5 WC Physics, Condensed Matter SC Physics GA 200ZW UT WOS:000080571000022 ER PT J AU Baumgartel, P Paggel, JJ Hasselblatt, M Horn, K Fernandez, V Schaff, O Weaver, JH Bradshaw, AM Woodruff, DP Rotenberg, E Denlinger, J AF Baumgartel, P Paggel, JJ Hasselblatt, M Horn, K Fernandez, V Schaff, O Weaver, JH Bradshaw, AM Woodruff, DP Rotenberg, E Denlinger, J TI Structure determination of the (root 3 x root 3) R30 degrees boron phase on the Si(111) surface using photoelectron diffraction SO PHYSICAL REVIEW B LA English DT Article ID SCANNING-TUNNELING-MICROSCOPY; SI(111)ROOT-3X-ROOT-3-B SURFACE; K/SI(111) INTERFACES; ELECTRONIC-STRUCTURE; SI; RECONSTRUCTION; SILICON; SPECTROSCOPY; ADSORPTION; RESOLUTION AB A quantitative structural analysis of the system Si(lll)(root 3 X root 3)R30 degrees-B has been performed using photo-electron diffraction in the scanned energy mode. We confirm that the substitutional Sg adsorption site is occupied and show that the interatomic separations to the three nearest-neighbor Si atoms are 1.98(+/-0.04) Angstrom, 2.14(+/-0.13) Angstrom,and 2.21(+/-0.12) Angstrom. These correspond to the silicon atom immediately below the boron atom, the adatom immediately above, and the three atoms to which it is coordinated symmetrically in the first layer. [S0163-1829(99)05819-1]. C1 Max Planck Gesell, Fritz Haber Inst, D-14195 Berlin, Germany. Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands, England. Lawrence Berkeley Lab, Adv Light Source, Berkeley, CA 94720 USA. Univ Wisconsin, Dept Phys, Milwaukee, WI 53211 USA. Univ Minnesota, Dept Chem Engn & Mat Sci, Minneapolis, MN 55455 USA. RP Baumgartel, P (reprint author), Max Planck Gesell, Fritz Haber Inst, Faradayweg 4-6, D-14195 Berlin, Germany. RI Rotenberg, Eli/B-3700-2009; Fernandez, Vincent/B-6411-2013 OI Rotenberg, Eli/0000-0002-3979-8844; NR 46 TC 22 Z9 22 U1 0 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1999 VL 59 IS 20 BP 13014 EP 13019 DI 10.1103/PhysRevB.59.13014 PG 6 WC Physics, Condensed Matter SC Physics GA 200ZW UT WOS:000080571000044 ER PT J AU Brown, DW Sokol, PE FitzGerald, SA AF Brown, DW Sokol, PE FitzGerald, SA TI Rotational dynamics of n-H-2 in porous Vycor glass SO PHYSICAL REVIEW B LA English DT Article ID MOLECULAR-HYDROGEN; NEUTRON-SCATTERING; ENERGY-LEVELS; SURFACE AB The rotational kinematics of normal H-2 confined to the pores of Vycor glass have been studied via incoherent inelastic neutron spectroscopy. At low temperature we observe two distinct rotational transitions. One is centered near 14 meV, corresponding to the free rotor value of molecular HZ, while the other is centered at similar to 10 meV. Measurements taken at filling fractions ranging from 10% to 95% allow us to ascribe the two transitions to H-2 in the center of the pore and H-2 strongly bound to the pore surface, respectively. The molecules bound to the surface are modeled as rotationally hindered rotors, and a distribution of orientation-dependent interaction potentials is extracted. The bound molecules can further be divided into a monolayer that is in direct contact with the pore wall, and a second, less tightly bound layer. The ortho to para conversion rate has also been measured and is higher than the bulk rate of 1.9%/h. The rate for the molecules bound to the pore wall is 2.1%/h, while the rate for molecules in the center of the pore is 8.5%/h. [S0163-1829(99)03920-X]. C1 Penn State Univ, Dept Phys, University Pk, PA 16802 USA. Natl Inst Stand & Technol, NIST Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Brown, DW (reprint author), Univ Calif Los Alamos Natl Lab, MS-H805,BLDG 622,TA-53, Los Alamos, NM 87545 USA. NR 23 TC 14 Z9 14 U1 1 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1999 VL 59 IS 20 BP 13258 EP 13266 DI 10.1103/PhysRevB.59.13258 PG 9 WC Physics, Condensed Matter SC Physics GA 200ZW UT WOS:000080571000073 ER PT J AU Gullikson, EM Stearns, DG AF Gullikson, EM Stearns, DG TI Asymmetric extreme ultraviolet scattering from sputter-deposited multilayers SO PHYSICAL REVIEW B LA English DT Article ID X-RAY-SCATTERING; STEPPED INTERFACES; ROUGHNESS; MIRRORS; SUPERLATTICES; REFLECTION AB Asymmetric scattering of extreme ultraviolet Light is observed from Mo/Si multilayers at normal incidence. The observed asymmetry is shown to depend on the geometry of the multilayer film deposition. However, atomic force microscopy (AFM) measurements of the top surface were isotropic, and there was no indication of columnar film growth either in the AFM or in TEM cross-sectional measurements. The scattering asymmetry is instead found to result from a skewed propagation of roughness within the multilayer. A modified film growth model is developed which describes this, and is also used to calculate the nonspecular scattering. The results of the model are in excellent agreement with the measurements. The scattering asymmetry can be used to determine the average deposition angle during the film growth. [S0163-1829(99)05120-6]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. OS Associates, Mt View, CA 94040 USA. RP Gullikson, EM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. NR 15 TC 5 Z9 5 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1999 VL 59 IS 20 BP 13273 EP 13277 DI 10.1103/PhysRevB.59.13273 PG 5 WC Physics, Condensed Matter SC Physics GA 200ZW UT WOS:000080571000075 ER PT J AU Jin, K Mahan, GD AF Jin, K Mahan, GD TI Tight-binding model of adsorbate structures SO PHYSICAL REVIEW B LA English DT Article ID ANGLE-RESOLVED UPS; CLUSTER IONS; RECONSTRUCTION; SURFACES; TRANSITION; DIFFUSION; ISLANDS; GROWTH AB Tight-binding calculations are presented of the ground state energies of metal atoms absorbed on the surface of the same or similar metals. We consider rows and clusters of adsorbate, and find significant energy variations as a function of the number of the atoms. Results are presented for the (001) face both for fee and bce crystals. General results that are applicable for any elemental fee or bcc crystal are obtained in the present paper. We include only s-wave tight-binding orbits in the nearest neighbor approximation. [S0163-1829(99)03120-3]. C1 Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Jin, K (reprint author), Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. NR 22 TC 1 Z9 1 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1999 VL 59 IS 20 BP 13309 EP 13313 DI 10.1103/PhysRevB.59.13309 PG 5 WC Physics, Condensed Matter SC Physics GA 200ZW UT WOS:000080571000081 ER PT J AU Friessnegg, T Madhukar, S Nielsen, B Moodenbaugh, AR Aggarwal, S Keeble, DJ Poindexter, EH Mascher, P Ramesh, R AF Friessnegg, T Madhukar, S Nielsen, B Moodenbaugh, AR Aggarwal, S Keeble, DJ Poindexter, EH Mascher, P Ramesh, R TI Metal ion and oxygen vacancies in bulk and thin film La1-xSrxCoO3 SO PHYSICAL REVIEW B LA English DT Article ID OXIDE SUPERCONDUCTORS; CRYSTAL-STRUCTURE; POSITRON; TRANSMISSION; TRANSITION AB Positron-lifetime and depth-resolved Doppler-broadening spectroscopy were used to investigate vacancies formed in bulk and laser ablated thin film La1-xSrxCoO3. In bulk samples, metal ion vacancies, which are most likely situated in the La sublattice, show a lifetime of 219 ps and a Doppler-broadening S parameter 1.06 times higher than the bulk. The metal-ion vacancy concentration increases with increasing Sr content. For x greater than or equal to 0.3, oxygen vacancies are detected, yielding a positron lifetime of 149 ps, only 10 ps longer than the bulk lifetime; the S parameter is 4% higher than for the bulk. For a given Sr concentration the films show a higher defect density than the bulk samples. The introduction of oxygen vacancy related defects is observed for increasing Sr doping concentration for both film and bulk samples. In films these defects probably consist of larger clusters and/or form complexes with metal ion vacancies. [S0163-1829(99)03519-5]. C1 Brookhaven Natl Lab, Div Mat Sci, Upton, NY 11973 USA. Univ Maryland, Dept Mat Sci & Nucl Engn, College Pk, MD 20742 USA. Univ Dundee, Carnegie Lab Phys, Dundee DD1 4HN, Scotland. USA, Res Lab, Adelphi, MD USA. McMaster Univ, Ctr Electrophoton Mat & Devices, Dept Engn Phys, Hamilton, ON L8S 4L7, Canada. Univ Maryland, Dept Mat Sci & Nucl Engn, College Pk, MD 20742 USA. RP Friessnegg, T (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Mat Sci Div Bldg 480, Upton, NY 11973 USA. EM friessn@bnl.gov RI Nielsen, Bent/B-7353-2009; Keeble, David /C-6633-2012; OI Nielsen, Bent/0000-0001-7016-0040; Keeble, David /0000-0002-5378-799X; Moodenbaugh, Arnold/0000-0002-3415-6762; Mascher, Peter/0000-0002-8108-0334 NR 22 TC 23 Z9 24 U1 2 U2 13 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1999 VL 59 IS 20 BP 13365 EP 13369 DI 10.1103/PhysRevB.59.13365 PG 5 WC Physics, Condensed Matter SC Physics GA 200ZW UT WOS:000080571000089 ER PT J AU Bzowski, A Kuhn, M Sham, TK Rodriguez, JA Hrbek, J AF Bzowski, A Kuhn, M Sham, TK Rodriguez, JA Hrbek, J TI Electronic structure of Au-Ag bimetallics: Surface alloying on Ru(001) SO PHYSICAL REVIEW B LA English DT Article ID NEAR-EDGE-STRUCTURE; CHARGE REDISTRIBUTION; THERMAL-DESORPTION; CHEMICAL-PROPERTIES; CU ALLOYS; CS-AU; LI-AU; PHOTOEMISSION; BEHAVIOR; FILMS AB We report a study of the electronic structure of Au-Ag overlayers (total coverage varies from 2 to 9 ML) supported on Ru(001). Photoemission spectroscopy with synchrotron radiation and a Mg K alpha x-ray source has been used to study the valence band and the Au 4f and Ag 3d core levels of these systems. It is found that, in most cases, two-dimensional alloy formation occurs upon deposition at room temperature. The extent of surface alloying depends on the order of deposition, composition, thickness, and annealing temperature. By comparing the valence band and binding energy shifts for bulk and surface alloys, we found that both systems exhibit the same trend: that is, that relative to the d band of pure Au, the alloy d band narrows and the Au 4f shifts to higher binding energy upon decreasing Au concentration. However, the surface alloy d band is consistently narrower than that of the bulk with the same stoichiometry. Similar surface bulk behavior is also seen in the Au 4f binding energy shift and the Au d-band doublets. This behavior is attributed to the two-dimensional nature (reduction in coordination number of like nearest neighbors on average) of the surface ahoy. [S0163-1829(99)01211-4]. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Univ Western Ontario, Dept Chem, London, ON N6A 5B7, Canada. RP Bzowski, A (reprint author), Scalacs Inc, 155 Hachborn Rd,Unit 3, Brantford, ON N3T 5M1, Canada. RI Hrbek, Jan/I-1020-2013 NR 30 TC 21 Z9 21 U1 0 U2 11 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1999 VL 59 IS 20 BP 13379 EP 13393 DI 10.1103/PhysRevB.59.13379 PG 15 WC Physics, Condensed Matter SC Physics GA 200ZW UT WOS:000080571000091 ER PT J AU Parks, EK Kerns, KP Riley, SJ Winter, BJ AF Parks, EK Kerns, KP Riley, SJ Winter, BJ TI Adsorption of C-60 on nickel clusters at high temperature SO PHYSICAL REVIEW B LA English DT Article ID METAL-FULLERENE CLUSTERS; IONIZATION-POTENTIALS; COATED FULLERENES; CHARGE-TRANSFER; IRON CLUSTERS; FRAGMENTATION; C60; STABILITY; SURFACES; PHOTOIONIZATION AB The adsorption of C-60 on nickel clusters has been studied in a flow-tube reactor at temperatures between 823 and 1073 K. Saturation coverages of C-60 have been determined for Ni-2-Ni-72 and show a size dependence consistent with C-60 adsorption on essentially spherical Ni-n clusters. There is no evidence for C-60 decomposition. The configuration of the adsorbed C-60 molecules appears to change from tetrahedral-->octahedral-->cubic-->less symmetrical arrangements as metal cluster size increases. An RRK modeling of the first C-60 that binds to the nickel clusters yields a binding energy in excess of 2.06 eV. The binding energy appears to decrease with decreasing metal nuclearity of the binding site, with binding to atop sites on the Ni-n clusters being relatively weak. It is argued that electron transfer to the C-60 ligands is limited by charging of the central Ni-n core and that this may provide a way of controlling the extent of electron transfer to the adsorbed molecules. [S0163-1829(99)03720-0]. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Max Born Inst Nichtlineare Opt Kurzzeitspektrosko, D-12489 Berlin, Germany. RP Parks, EK (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Winter, Bernd/D-4657-2011 NR 50 TC 17 Z9 17 U1 1 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1999 VL 59 IS 20 BP 13431 EP 13445 DI 10.1103/PhysRevB.59.13431 PG 15 WC Physics, Condensed Matter SC Physics GA 200ZW UT WOS:000080571000096 ER PT J AU Choi, JW Zhang, JD Liou, SH Dowben, PA Plummer, EW AF Choi, JW Zhang, JD Liou, SH Dowben, PA Plummer, EW TI Surfaces of the perovskite manganites La1-xCaxMnO3 SO PHYSICAL REVIEW B LA English DT Article ID X-RAY PHOTOEMISSION; VALENCE-BAND STRUCTURE; EPITAXIAL THIN-FILMS; COLOSSAL MAGNETORESISTANCE; BINARY-ALLOYS; SEGREGATION; SPECTROSCOPY; ELECTRON; PHOTOELECTRON; FERROMAGNET AB Angle-resolved core-level photoemission has been utilized to study the surfaces of crystalline thin films of manganite La1-xCaxMnO3 (x = 0.1 and 0.35). It is found that both the surface termination and Ca surface concentration depend on the bulk Ca concentration. For La0.65Ca0.35MnO3, the terminal layer is predominately Mn-O, while for La0.9Ca0.1MnO3, the majority of the surface is La/Ca-O terminated. Both surfaces exhibit a large enhancement in the Ca concentration compared to the bulk with the La0.9Ca0.1MnO3 sample, having a larger surface Ca concentration than for the La0.65Ca0.35MnO3 material. [S0163-1829(99)04420-3]. C1 Univ Nebraska, Dept Phys & Astron, Lincoln, NE 68588 USA. Univ Nebraska, Ctr Mat Res & Anal, Behlen Lab Phys, Lincoln, NE 68588 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. RP Choi, JW (reprint author), Univ Nebraska, Dept Phys & Astron, Lincoln, NE 68588 USA. NR 28 TC 75 Z9 75 U1 1 U2 14 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1999 VL 59 IS 20 BP 13453 EP 13459 DI 10.1103/PhysRevB.59.13453 PG 7 WC Physics, Condensed Matter SC Physics GA 200ZW UT WOS:000080571000098 ER PT J AU Balasubramanian, V Kraus, P Lawrence, A Trivedi, SP AF Balasubramanian, V Kraus, P Lawrence, A Trivedi, SP TI Holographic probes of anti-de Sitter spacetimes SO PHYSICAL REVIEW D LA English DT Article ID GAUGED EXTENDED SUPERGRAVITY; STRING THEORY; BLACK-HOLE; DESITTER SPACE; FIELD-THEORY; ABSORPTION; STABILITY; BRANES; WORLD AB We describe probes of anti-de Sitter spacetimes in terms of conformal field theories on the AdS boundary. Our basic tool is a formula that relates bulk and boundary states-classical bulk field configurations are dual to expectation values of operators on the boundary. At the quantum level we relate the operator expansions of bulk and boundary fields. Using our methods, we discuss the CFT description of local bulk probes including normalizable wave packets, fundamental and D-strings, and D-instantons. Radial motions of probes in the bulk spacetime are related to motions in scale on the boundary, demonstrating a scale-radius duality. We discuss the implications of these results for the holographic description of black hole horizons in the boundary field theory. [S0556-2821(99)03808-4]. C1 Harvard Univ, Lyman Lab Phys, Cambridge, MA 02138 USA. CALTECH, Pasadena, CA 91125 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Balasubramanian, V (reprint author), Harvard Univ, Lyman Lab Phys, Cambridge, MA 02138 USA. EM vijayb@curie.harvard.edu; perkraus@theory.caltech.edu; lawrence@string.harvard.edu; trivedi@fnth23.fnal.gov OI Lawrence, Albion/0000-0003-4116-045X NR 35 TC 258 Z9 258 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAY 15 PY 1999 VL 59 IS 10 AR 104021 DI 10.1103/PhysRevD.59.104021 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 198UE UT WOS:000080442000039 ER PT J AU de Gouvea, A Friedland, A Murayama, H AF de Gouvea, A Friedland, A Murayama, H TI Seiberg duality and e(+)e(-) experiments SO PHYSICAL REVIEW D LA English DT Article ID GAUGE-THEORIES; INSTANTON CALCULUS AB Seiberg duality in supersymmetric gauge theories is the claim that two different theories describe the same physics in the infrared limit. However, one cannot easily work out physical quantities in strongly coupled theories and hence it has been difficult to compare the physics of the electric and magnetic theories. In order to gain more insight into the equivalence of two theories, we study the "e(+)e(-)" cross sections into "hadrons" for both theories in the superconformal window. We describe a technique which allows us to compute the cross sections exactly in the infrared limit. They are indeed equal in the low-energy limit and the equality is guaranteed because of the anomaly matching condition. The ultraviolet behavior of the total ''e(+)e(-)" cross section is different for the two theories. We comment on proposed non-supersymmetric dualities. We also analyze the agreement of the "gamma gamma'' and ''WW'' scattering amplitudes in both theories, and in particular try to understand if their equivalence can be explained by the anomaly matching condition. [S0556-2821(99)02310-3]. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. CERN, Div Theory, CH-1211 Geneva, Switzerland. RP de Gouvea, A (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Murayama, Hitoshi/A-4286-2011 NR 11 TC 0 Z9 0 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAY 15 PY 1999 VL 59 IS 10 AR 105008 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 198UE UT WOS:000080442000047 ER PT J AU Han, T Lykken, JD Zhang, RJ AF Han, T Lykken, JD Zhang, RJ TI Kaluza-Klein states from large extra dimensions SO PHYSICAL REVIEW D LA English DT Article ID HETEROTIC STRING THEORY; CHIRAL GAUGE-THEORIES; SUPERSYMMETRY BREAKING; D-BRANES; TEV; COMPACTIFICATION; SUPERGRAVITY; UNIFICATION; MILLIMETER; BOUNDARY AB We consider the novel Kaluza-Klein (KK) scenario where gravity propagates in the (4 + n)-dimensional bulk of spacetime, while gauge and matter fields are confined to the (3 + 1)-dimensional world volume of a brane configuration. For simplicity we assume compactification of the extra n dimensions on a torus with a common scale R, and identify the massive KK states in the four-dimensional spacetime. For a given KK level (n) over right arrow there is one spin-2 state, (n - 1) spin-1 states, and n(n - 1)/2 spin-0 states, all mass degenerate. We construct the effective interactions between these KK states and ordinary matter fields (fermions, gauge bosons, and scalars). We find that the spin-1 states decouple and that the spin-0 states only couple through the dilaton mode. We then derive the interacting Lagrangian for the KK states and standard model fields, and present the complete Feynman rules. We discuss some low-energy phenomenology for these new interactions for the case when 1/R is small compared to the electroweak scale, and the ultraviolet cutoff of the effective KK theory is on the order of 1 TeV. [S0556-2821(99)05408-9]. C1 Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Fermi Natl Accelerator Lab, Theory Grp, Batavia, IL 60510 USA. RP Han, T (reprint author), Univ Wisconsin, Dept Phys, 1150 Univ Ave, Madison, WI 53706 USA. NR 62 TC 663 Z9 665 U1 0 U2 8 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAY 15 PY 1999 VL 59 IS 10 AR 105006 DI 10.1103/PhysRevD.59.105006 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 198UE UT WOS:000080442000045 ER PT J AU Kachru, S Kumar, J Silverstein, E AF Kachru, S Kumar, J Silverstein, E TI Vacuum energy cancellation in a nonsupersymmetric string SO PHYSICAL REVIEW D LA English DT Article ID MULTILOOP SUPERSTRING AMPLITUDES; CONFORMAL FIELD-THEORIES; MODULAR INVARIANCE; PERTURBATION-THEORY; COSMOLOGICAL CONSTANT; CHIRAL BOSONIZATION; ORBIFOLDS; GAUGE; SURFACE AB We present a nonsupersymmetric orbifold of type II string theory and show that it has a vanishing cosmological constant at the one and two loop levels. We argue heuristically that the cancellation may persist at higher loops. [S0556-2821(99)04808-0]. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Stanford Univ, Dept Phys, Stanford, CA 94305 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Kachru, S (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NR 38 TC 62 Z9 62 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAY 15 PY 1999 VL 59 IS 10 AR 106004 DI 10.1103/PhysRevD.59.106004 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 198UE UT WOS:000080442000066 ER PT J AU Lopez, RE Turner, MS AF Lopez, RE Turner, MS TI Precision prediction for the big-bang abundance of primordial He-4 SO PHYSICAL REVIEW D LA English DT Article ID WAVE-FUNCTION RENORMALIZATION; FINITE-TEMPERATURE; EARLY UNIVERSE; RADIATIVE-CORRECTIONS; HELIUM ABUNDANCE; NUCLEOSYNTHESIS; UNCERTAINTIES; NEUTRINOS; PHYSICS; NUMBER AB Within the standard models of particle physics and cosmology we have calculated the big-bang prediction for the primordial abundance of He-4 to a theoretical uncertainty of less than 0.1% (delta Y-P < +/-0.0002), improving the current theoretical precision by a factor of 10. At this accuracy the uncertainty in the abundance is dominated by the experimental uncertainty in the neutron mean lifetime, tau(n) = 885.4 +/- 2.0 sec. The following physical effects were included in the calculation: the zero and finite-temperature radiative, Coulomb and finite-nucleon-mass corrections to the weak rates; order-alpha quantum-electrodynamic correction to the plasma density, electron mass, and neutrino temperature; and incomplete neutrino decoupling. New results for the finite-temperature radiative correction and the QED plasma correction were used. In addition, we wrote a new and independent nucleosynthesis code designed to control numerical errors to be less than 0.1%. Our predictions for the He-4 abundance are presented in the form of an accurate fitting formula. Summarizing our work in one number, Y-P(eta = 5 X 10(-10)) = 0.2462 +/- 0.0004 (expt) +/- <0.0002 (theory). Further, the baryon density inferred from the Burles-Tytler determination of the primordial D abundance, Omega(B)h(2) = 0.019 +/- 0.001, leads to the prediction Y-P = 0.2464 +/- 0.0005 (D/H) +/- <0.0002 (theory) +/-0.0005 (expt). This "prediction" and an accurate measurement of the primeval He-4 abundance will allow an important consistency test of primordial nucleosynthesis. [S0556-2821(99)05106-1]. C1 Univ Chicago, Dept Phys, Chicago, IL 60637 USA. Fermi Natl Accelerator Lab, NASA Fermilab Astrophys Ctr, Batavia, IL 60510 USA. Univ Chicago, Enrico Fermi Inst, Dept Astron & Astrophys, Chicago, IL 60637 USA. RP Lopez, RE (reprint author), Univ Chicago, Dept Phys, Chicago, IL 60637 USA. NR 57 TC 112 Z9 112 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAY 15 PY 1999 VL 59 IS 10 AR 103502 DI 10.1103/PhysRevD.59.103502 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 198UE UT WOS:000080442000012 ER PT J AU Waga, I Miceli, APMR AF Waga, I Miceli, APMR TI Cosmological constraints from lensing statistics and supernovae on the cosmic equation of state SO PHYSICAL REVIEW D LA English DT Article ID DECAYING LAMBDA-COSMOLOGIES; GRAVITATIONAL LENSES; SCALAR FIELD; LUMINOSITY FUNCTION; CONSTANT; MODELS; EVOLUTION; UNIVERSE; DENSITY; QUASARS AB We investigate observational constraints from lensing statistics and high-z type Ia supernovae on flat cosmological models with nonrelativistic matter and an exotic fluid with an equation of state, p(x)=(m/3-1)rho(x). We show that agreement with both tests at the 68% confidence level is possible if the parameter m is low (m less than or similar to 0.85) and 0.24 less than or similar to Omega(m0)less than or similar to 0.38 with lower values of Omega(m0) corresponding to higher m. We find that a conventional cosmological constant model with Omega(m0)similar or equal to 0.33 is the best fit model of the combined likelihood. [S0556-2821(99)04410-0]. C1 Univ Fed Rio de Janeiro, Inst Fis, BR-21945970 Rio De Janeiro, Brazil. Fermi Natl Accelerator Lab, NASA Fermilab Astrophys Ctr, Batavia, IL 60510 USA. RP Waga, I (reprint author), Univ Fed Rio de Janeiro, Inst Fis, Caixa Postal 68528, BR-21945970 Rio De Janeiro, Brazil. RI Waga, Ioav/B-6288-2014 NR 58 TC 45 Z9 45 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAY 15 PY 1999 VL 59 IS 10 AR 103507 DI 10.1103/PhysRevD.59.103507 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 198UE UT WOS:000080442000017 ER PT J AU Johnson, SK Houk, LL Johnson, DC Houk, RS AF Johnson, SK Houk, LL Johnson, DC Houk, RS TI Determination of small carboxylic acids by capillary electrophoresis with electrospray-mass spectrometry SO ANALYTICA CHIMICA ACTA LA English DT Article DE capillary electrophoresis; electrospray-mass spectrometry; carboxylic acids ID ZONE ELECTROPHORESIS; ORGANIC-ACIDS; GAS-CHROMATOGRAPHY; SEPARATION; INTERFACE; SAMPLES; ANIONS; FLOW AB Capillary electrophoresis (CE) is used with electrospray-mass spectrometry (ES-MS) to analyze a mixture of succinic, maleic, malonic, and glutaric acids as the negative parent ions ([M-H](-)). The CE is coupled with the ES-MS via a make-up sheath flow. The CE mobile phase consists of an aqueous solution of naphthalene disulfonate (NDS), pyromellitic acid, and methanol, with diethylene triamine (DETA) as an electroosmotic flow modifier. Compromise experimental parameters for the CE separation and ES-MS detection are evaluated. Detection limits for CE-ES-MS determination of the sample are 1-10 ppm or 60-600 pg. The carboxylic acid sample is injected directly into the CE column with little or no preparation. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ, US DOE, Ames Lab, Dept Chem, Ames, IA 50011 USA. RP Houk, RS (reprint author), Iowa State Univ, US DOE, Ames Lab, Dept Chem, Ames, IA 50011 USA. NR 43 TC 40 Z9 41 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0003-2670 J9 ANAL CHIM ACTA JI Anal. Chim. Acta PD MAY 14 PY 1999 VL 389 IS 1-3 BP 1 EP 8 DI 10.1016/S0003-2670(99)00122-1 PG 8 WC Chemistry, Analytical SC Chemistry GA 200FA UT WOS:000080527900001 ER PT J AU Silman, I Millard, CB Ordentlich, A Greenblatt, HM Harel, M Barak, D Shafferman, A Sussman, JL AF Silman, I Millard, CB Ordentlich, A Greenblatt, HM Harel, M Barak, D Shafferman, A Sussman, JL TI A preliminary comparison of structural models for catalytic intermediates of acetylcholinesterase SO CHEMICO-BIOLOGICAL INTERACTIONS LA English DT Article; Proceedings Paper CT 3th International Meeting on Esterases Reacting with Organophosphorus Compounds CY APR 15-18, 1998 CL INTER UNVI CTR, DUBROVNIK, CROATIA SP INst Med Res & Occupat Hlth, Minist Sci & Technol Republ Croatia, Minist Def Republ Croatia, Us Army Med Res & Mat Command, Assoc European Toxicol & Sci Toxicol, Netherlands & Novartis Crop Protect AG HO INTER UNVI CTR DE soman; trifluoroketones; tetrahedral intermediate; X-ray crystallography ID HUMAN BUTYRYLCHOLINESTERASE; SUBSTRATE-SPECIFICITY; PROTEIN INTERACTIONS; TORPEDO-CALIFORNICA; SERINE PROTEASES; BINDING; SITE; ORGANOPHOSPHATES; CHYMOTRYPSIN; INHIBITORS AB Determination of the three dimensional structure of Torpedo Californica acetylcholinesterase (TcAChE) provided an experimental tool for directly visualizing interaction of AChE with cholinesterase inhibitors of fundamental, pharmacological and toxicological interest. The structure revealed that the active site is located near the bottom of a deep and narrow gorge lined with 14 conserved aromatic amino acids. The structure of a complex of TcAChE with the powerful 'transition state analog' inhibitor, TMTFA, suggested that its orientation in the experimentally determined structure was very similar to that proposed for the natural substrate, acetylcholine. by manual docking. The array of enzyme-ligand interactions Visualized in the TMFTA complex also are expected to envelope the unstable TI that forms with acetylcholine during acylation, and to sequester it from solvent. In our most recent studies, the crystal structures of several 'aged' conjugates of TcAChE obtained with OP nerve agents have been solved and compared with that of the native enzyme. The methylphosphonylated-enzyme obtained by reaction with soman provides a useful structural analog for the TI that forms during deacylation after the reaction of TcAChE with acetylcholine. By comparing these structures, we conclude that the same 'oxyanion hole' residues, as well as the aromatic side chains constituting the 'acyl pocket', participate in acylation (TMTFA-AChE) and deacylation (OP-AChE), and that AChE can accommodate both TIs at the bottom of the gorge without major conformational movements. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved. C1 Weizmann Inst Sci, Dept Neurobiol, IL-76100 Rehovot, Israel. USA, Med Res Inst Chem Def, Aberdeen Proving Ground, MD 21010 USA. Israel Inst Biol Res, IL-70450 Ness Ziona, Israel. Weizmann Inst Sci, Dept Biol Struct, IL-76100 Rehovot, Israel. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Silman, I (reprint author), Weizmann Inst Sci, Dept Neurobiol, IL-76100 Rehovot, Israel. EM bnsilm@weizmann.weizmann.ac.il OI Sussman, Joel/0000-0003-0306-3878 NR 36 TC 21 Z9 21 U1 1 U2 6 PU ELSEVIER IRELAND LTD PI CLARE PA ELSEVIER HOUSE, BROOKVALE PLAZA, EAST PARK SHANNON, CO, CLARE, 00000, IRELAND SN 0009-2797 J9 CHEM-BIOL INTERACT JI Chem.-Biol. Interact. PD MAY 14 PY 1999 VL 119 BP 43 EP 52 DI 10.1016/S0009-2797(99)00012-5 PG 10 WC Biochemistry & Molecular Biology; Pharmacology & Pharmacy; Toxicology SC Biochemistry & Molecular Biology; Pharmacology & Pharmacy; Toxicology GA 211WG UT WOS:000081184400005 PM 10421437 ER PT J AU Balatsky, AV Shen, ZX AF Balatsky, AV Shen, ZX TI Condensed matter physics - Is this why T-c is so low? SO SCIENCE LA English DT Editorial Material ID OXIDE SUPERCONDUCTORS; PHOTOEMISSION; TEMPERATURE; YBA2CU4O8 C1 Univ Calif Los Alamos Natl Lab, Condensed Matter Grp, Div Theoret, Los Alamos, NM 87545 USA. Stanford Univ, Stanford Synchrotron Radiat Lab, Stanford, CA 94305 USA. Stanford Univ, Dept Phys, Stanford, CA 94305 USA. Stanford Univ, Dept Appl Phys, Stanford, CA 94305 USA. RP Balatsky, AV (reprint author), Univ Calif Los Alamos Natl Lab, Condensed Matter Grp, Div Theoret, POB 1663, Los Alamos, NM 87545 USA. NR 15 TC 25 Z9 25 U1 0 U2 2 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAY 14 PY 1999 VL 284 IS 5417 BP 1137 EP 1138 DI 10.1126/science.284.5417.1137 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 197HJ UT WOS:000080359100026 ER PT J AU DeLucia, EH Hamilton, JG Naidu, SL Thomas, RB Andrews, JA Finzi, AC Lavine, M Matamala, R Mohan, JE Hendrey, GR Schlesinger, WH AF DeLucia, EH Hamilton, JG Naidu, SL Thomas, RB Andrews, JA Finzi, AC Lavine, M Matamala, R Mohan, JE Hendrey, GR Schlesinger, WH TI Net primary production of a forest ecosystem with experimental CO2 enrichment SO SCIENCE LA English DT Article ID RISING ATMOSPHERIC CO2; LOBLOLLY-PINE; ELEVATED CO2; GROWTH TRENDS; UNITED-STATES; TREE GROWTH; SODA-LIME; RESPONSES; BIOMASS; CLIMATE AB The concentration of atmospheric carbon dioxide was increased by 200 microliters per Liter in a forest plantation, where competition between organisms, resource Limitations, and environmental stresses may modulate biotic responses. After 2 years the growth rate of the dominant pine trees increased by about 26 percent relative to trees under ambient conditions. Carbon dioxide enrichment also increased Litterfall and fine-root increment. These changes increased the total net primary production by 25 percent. Such an increase in forest net primary production globally would fix about 50 percent of the anthropogenic carbon dioxide projected to be released into the atmosphere in the year 2050. The response of this young, rapidly growing forest to carbon dioxide may represent the upper Limit for forest carbon sequestration. C1 Univ Illinois, Dept Plant Biol, Urbana, IL 61801 USA. W Virginia Univ, Dept Biol, Morgantown, WV 26506 USA. Duke Univ, Inst Stat & Decis Sci, Durham, NC 27708 USA. Brookhaven Natl Lab, Div Biosyst, Upton, NY 11973 USA. RP DeLucia, EH (reprint author), Univ Illinois, Dept Plant Biol, Urbana, IL 61801 USA. EM delucia@uiuc.edu RI Finzi, Adrien/A-7017-2016 OI Finzi, Adrien/0000-0003-2220-4533 NR 37 TC 325 Z9 365 U1 4 U2 78 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAY 14 PY 1999 VL 284 IS 5417 BP 1177 EP 1179 DI 10.1126/science.284.5417.1177 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 197HJ UT WOS:000080359100040 ER PT J AU Patel, RR Garrett, HE Emanuel, MA Larson, MC Pocha, MD Krol, DM Deri, RJ Lowry, ME AF Patel, RR Garrett, HE Emanuel, MA Larson, MC Pocha, MD Krol, DM Deri, RJ Lowry, ME TI WDM filter modules in compact, low-cost plastic packages for byte-wide multimode fibre ribbon, cable data links SO ELECTRONICS LETTERS LA English DT Article AB WDM filter modules are presented for multimode fibre ribbon Cables which employ a simple package and provide low crosstalk and sharp passband edges, suitable for 10nm channel spacing. These devices exhibit low insertion loss (1.6dB average) and good wavelength uniformity (+/- 0.8nm). C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Patel, RR (reprint author), Univ Calif Lawrence Livermore Natl Lab, 700 E Ave, Livermore, CA 94550 USA. NR 6 TC 2 Z9 2 U1 0 U2 0 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 0013-5194 J9 ELECTRON LETT JI Electron. Lett. PD MAY 13 PY 1999 VL 35 IS 10 BP 840 EP 842 DI 10.1049/el:19990537 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA 204DD UT WOS:000080746900058 ER PT J AU Jhi, SH Ihm, J Louie, SG Cohen, ML AF Jhi, SH Ihm, J Louie, SG Cohen, ML TI Electronic mechanism of hardness enhancement in transition-metal carbonitrides SO NATURE LA English DT Article ID SOLIDS AB Transition-metal carbides and nitrides are hard materials widely used for cutting tools and wear-resistant coatings. Their hardness is not yet understood at a fundamental level, A clue may lie in the puzzling fact that transition-metal carbonitrides that have the rock-salt structure (such as TiCxN1-x) have the greatest hardness for a valence-electron concentration of about 8.4 per cell(1-3), which suggests that the hardness may be determined more by the nature of the bonding than by the conventional microstructural features that determine the hardness of structural metals and alloys. To investigate this possibility, we have evaluated the shear modulus of various transition-metal carbides and nitrides using nb initio pseudopotential calculations. Our results show that the behaviour of these materials can be understood on a fundamental level in terms of their electronic band structure. The unusual hardness originates from a particular band of sigma bonding states between the non-metal p orbitals and the metal d orbitals that strongly resists shearing strain or shape change. Filling of these states is completed at a valence-electron concentration of about 8.4, and any additional electrons would go into a higher band which is unstable against shear deformations. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Seoul Natl Univ, Dept Phys, Seoul 151742, South Korea. Seoul Natl Univ, Ctr Theoret Phys, Seoul 151742, South Korea. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Louie, SG (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NR 17 TC 400 Z9 418 U1 9 U2 66 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAY 13 PY 1999 VL 399 IS 6732 BP 132 EP 134 DI 10.1038/20148 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 196XU UT WOS:000080335700044 ER PT J AU Goity, JL Lewis, R Schvellinger, M Zhang, LZ AF Goity, JL Lewis, R Schvellinger, M Zhang, LZ TI The Goldberger-Treiman discrepancy in SU(3) SO PHYSICS LETTERS B LA English DT Article ID CHIRAL PERTURBATION-THEORY; NN COUPLING-CONSTANT; NUCLEON; SCATTERING AB The Goldberger-Treiman discrepancy in SU(3) is analyzed in the framework of heavy baryon chiral perturbation theory (HBChPT). It is shown that the discrepancy at leading order is entirely given by counterterms from the O(p(3)) Lagrangian, and that the first subleading corrections are suppressed by two powers in the HBChPT expansion. These subleading corrections include meson-loop contributions as well as counterterms from the O(p(5)) Lagrangian. Some one-loop contributions are calculated and found to be small. Using the three discrepancies (pi NN, KN Lambda and KN Sigma) which can be extracted from existing experimental data, we find that the HBChPT calculation favors the smaller g(pi NN) values obtained in recent partial wave analyses. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Jefferson Lab, Newport News, VA 23606 USA. Hampton Univ, Dept Phys, Hampton, VA 23668 USA. Univ Regina, Dept Phys, Regina, SK S4S 0A2, Canada. Natl Univ La Plata, Dept Phys, RA-1900 La Plata, Argentina. RP Goity, JL (reprint author), Jefferson Lab, 12000 Jefferson Ave, Newport News, VA 23606 USA. NR 23 TC 21 Z9 21 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD MAY 13 PY 1999 VL 454 IS 1-2 BP 115 EP 122 DI 10.1016/S0370-2693(99)00217-8 PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 205WE UT WOS:000080842900018 ER PT J AU Hay, PJ Redondo, A Guo, YJ AF Hay, PJ Redondo, A Guo, YJ TI Theoretical studies of pentene cracking on zeolites: C-C beta-scission processes SO CATALYSIS TODAY LA English DT Article; Proceedings Paper CT 1996 American-Chemical-Society Symposium on the Advances and Applications of Computational Chemical Modeling to Heterogeneous catalysis CY 1996 CL SAN FRANCISCO, CALIFORNIA SP Amer Chem Soc DE beta-scission processes; pentyl carbenium ion; pentene cracking; density functional theory ID MECHANISMS; MOLECULES AB The C-C bond-breaking step of pentene adsorbed on a model zeolite cluster is examined using ab initio and density functional theory (DFT/B3LYP) electronic structure techniques as an example of the p-scission process that arises in cracking of alkanes and alkenes. After pentene has been protonated by the acid site, the reactant for the cracking process corresponds to a pentyl cation covalently bound to the oxygen of the zeolite, ZO(-)-C5H11+. The product of the C-C bond-breaking process is propene plus an ethyl cation bound to a neighboring oxygen. The energy of the transition state relative from B3LYP calculations is 60 kcal/mol relative to the pentyl cationic reactant. For the case of the branched olefin methyl pentene, the transition state energy is slightly lower (55 kcal/mol), but the overall reaction energy is essentially the same as for pentene. The results are compared to the case of the gas phase pentyl carbenium ion. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Redondo, A (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, T-12,MS B268, Los Alamos, NM 87545 USA. NR 23 TC 27 Z9 27 U1 0 U2 15 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5861 J9 CATAL TODAY JI Catal. Today PD MAY 12 PY 1999 VL 50 IS 3-4 BP 517 EP 523 PG 7 WC Chemistry, Applied; Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA 192VF UT WOS:000080099700006 ER PT J AU Goldbach, A Johnson, J Meisel, D Curtiss, LA Saboungi, ML AF Goldbach, A Johnson, J Meisel, D Curtiss, LA Saboungi, ML TI On the constituents of aqueous polyselenide electrolytes: A combined theoretical and Raman spectroscopic study SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID PHOTOELECTROCHEMICAL CELLS; CRYSTAL-STRUCTURE; SELENIUM; IONS; ANIONS; SPECIATION; SE-2(-); STATE AB The speciation of aqueous polyselenide solutions at high pH values has been investigated by Raman and UV/vis absorption spectroscopy. Complementary, ab initio molecular orbital calculations at the HF/6-31+G* level of theory have been carried out on the vibrational frequencies of polyselenide dianions Se-x(2-) (x = 2-4), polyselenide radical anions Se-x(-) (x = 2, 3), and protonated polyselenides HSex- (x = 1-3) in order to substantiate the assignment of the experimental Raman spectra. Although the optical spectra suggest the successive formation of Se-2(2-), Se-3(2-), and Se-4(2-) with progressive oxidation of the solutions, only two characteristic Raman bands are observed at 269 and 324 cm(-1). A sequence of overtones of the 269 cm(-1) band is observed after excitation with blue light. Likewise strong overtones of the 324 cm(-1) band appear after excitation with green light. The 269 cm(-1) feature is assigned to Se-4(2-) while uhe 324 cm(-1) band is attributed to the radical anion Se-2(-). The occurrence of polyselenide radicals in aqueous solution is without precedent, and the formation of Se-2(-) is ascribed to a photolytic process in the electrolyte. The only protonated species observed in this study is HSe-, which is characterized by a Raman band at 2303 cm(-1). C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Saboungi, ML (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. EM mls@anl.gov RI Saboungi, Marie-Louise/C-5920-2013; Johnson, Jacqueline/P-4844-2014 OI Saboungi, Marie-Louise/0000-0002-0607-4815; Johnson, Jacqueline/0000-0003-0830-9275 NR 34 TC 13 Z9 13 U1 1 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD MAY 12 PY 1999 VL 121 IS 18 BP 4461 EP 4467 DI 10.1021/ja9836186 PG 7 WC Chemistry, Multidisciplinary SC Chemistry GA 200PY UT WOS:000080550100019 ER PT J AU Carey, DC AF Carey, DC TI Standardization of beam line representations SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 5th International Conference on Charged Particle Optics CY APR 14-17, 1998 CL DELFT, NETHERLANDS AB Standardization of beam line representations means that a single set of data can be used in many situations to represent a beam line. This set of data should be the same no matter what the program to be run or the calculation to be made. We have concerned ourselves with three types of standardization: (1) The same set of data should be usable by different programs. (2) The inclusion of other items in the data, such as calculations to be done, units to be used, or preliminary specifications, should be in a notation similar to the lattice specification. (3) A single set of data should be used to represent a given beam line, no matter what is being modified or calculated. The specifics of what is to be modified or calculated can be edited into the data as part of the calculation. These three requirements all have aspects not previously discussed in a public forum. Implementations into TRANSPORT [1] will be discussed. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Carey, DC (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 11 PY 1999 VL 427 IS 1-2 BP 1 EP 5 DI 10.1016/S0168-9002(98)01533-2 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 202XV UT WOS:000080678200002 ER PT J AU Wan, WS Johnstone, C Holt, J Berz, M Makino, K Lindemann, M Erdelyi, B AF Wan, WS Johnstone, C Holt, J Berz, M Makino, K Lindemann, M Erdelyi, B TI The influence of fringe fields on particle dynamics in the Large Hadron Collider SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 5th International Conference on Charged Particle Optics CY APR 14-17, 1998 CL DELFT, NETHERLANDS DE LHC; fringe fields; tune shifts; resonance strengths AB The need of maximizing luminosity in the Large Hadron Collider requires the use of high-gradient quadrupoles in the interaction region. These quadrupoles combine relatively short length, large aperture, and short focal length with a rather peculiar configuration of the return coils, all of which enhances the relevance of their fringe field effects. The influence of resulting nonlinearities on the dynamics is analyzed via high-order maps determined with differential algebraic (DA) techniques and the code COSY INFINITY. Normal form methods are utilized to determine amplitude-dependent tune shifts as well as resonance strengths. An analysis based on a detailed description of the fringe field of the superconducting quadrupoles reveals that the strength of resonances increases by more than one order of magnitude, and that amplitude-dependent tune shifts are enhanced substantially. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Fermi Natl Accelerator Lab, Beams Div, Batavia, IL 60510 USA. Michigan State Univ, E Lansing, MI 48824 USA. Natl Superconducting Cyclotron Lab, E Lansing, MI 48824 USA. RP Wan, WS (reprint author), Fermi Natl Accelerator Lab, Beams Div, POB 500, Batavia, IL 60510 USA. NR 7 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 11 PY 1999 VL 427 IS 1-2 BP 74 EP 78 DI 10.1016/S0168-9002(98)01521-6 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 202XV UT WOS:000080678200016 ER PT J AU Leitner, MA Leung, KN AF Leitner, MA Leung, KN TI Optimization of the volume H- ion source extraction system for the Spallation Neutron Source accelerator utilizing 3D magnet and ion optics codes SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 5th International Conference on Charged Particle Optics CY APR 14-17, 1998 CL DELFT, NETHERLANDS DE H- ion source; negative ion source; ion beam optics; negative ion beam extraction; plasma extraction simulation; low-energy beam transport AB The H- beam extraction from the multicusp ion source for the Spallation Neutron Source (SNS) is being simulated utilizing the 3D ion optics code KOBRA and the 3D magnet code TOSCA. Design of the extraction system for the SNS project requires proper simulation of the extraction of both electrons and H- ions. The goal is to optimize the magnetic field of the extraction system so that the electrons are completely deflected and captured at the plasma electrode. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Ernest Orlando Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Leitner, MA (reprint author), Lawrence Berkeley Nalt Lab, Div Accelerator & Fus Res, 1 Cyclotron Rd,Mailstop 5-119, Berkeley, CA 94720 USA. NR 5 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 11 PY 1999 VL 427 IS 1-2 BP 250 EP 254 DI 10.1016/S0168-9002(98)01550-2 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 202XV UT WOS:000080678200046 ER PT J AU Berz, M Erdelyi, B Wan, WS Ng, KY AF Berz, M Erdelyi, B Wan, WS Ng, KY TI Differential algebraic determination of high-order off-energy closed orbits, chromaticities, and momentum compactions SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 5th International Conference on Charged Particle Optics CY APR 14-17, 1998 CL DELFT, NETHERLANDS DE maps; differential algebraic methods; momentum compaction; off-energy closed orbit; chromaticity AB For some modern particle accelerators, including the planned muon collider, the accurate analysis of non-linear time-of-flight effects in the form of momentum compactions is critical for the preservation of bunch structure. A Differential Algebra-based (DA) method is presented that allows the determination of off-energy closed orbits and chromaticities to any order. By performing a coordinate transformation to the off-energy closed orbit, it is possible to compute momentum compactions analytically. This method has been implemented in the code COSY INFINITY and is tested for two cases where analytical solutions can be obtained by hand; agreement to machine precision is found. By contrast, comparisons are made with several codes that use conventional numerical methods for the determination of momentum compaction, and it is found that these approaches sometimes yield rather inaccurate results, especially for higher orders. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Michigan State Univ, E Lansing, MI 48824 USA. Natl Superconducting Cyclotron Lab, E Lansing, MI 48824 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Erdelyi, B (reprint author), Michigan State Univ, E Lansing, MI 48824 USA. NR 11 TC 4 Z9 4 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 11 PY 1999 VL 427 IS 1-2 BP 310 EP 314 DI 10.1016/S0168-9002(98)01538-1 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 202XV UT WOS:000080678200057 ER PT J AU Gillespie, GH Brown, TA AF Gillespie, GH Brown, TA TI Optics elements for modeling electrostatic lenses and accelerator components II. Acceleration columns SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 5th International Conference on Charged Particle Optics CY APR 14-17, 1998 CL DELFT, NETHERLANDS DE computer codes; particle optics; accelerator design; electrostatic accelerator AB A set of optical models for a variety of electrostatic lenses and accelerator columns has been developed for the computer code TRACE 3-D. TRACE 3-D is an envelope (matrix) code including space charge that is often used to model bunched beams in magnetic transport systems and radiofrequency (RF) accelerators when the effects of beam current may be important. Several new matrix models have been developed that allow the code to be used for modeling beam lines and accelerators with electrostatic components. The new models include a number of options for: (I) einzel lenses, (2) accelerator columns, (3) electrostatic deflectors (prisms), and (4) an electrostatic quadrupole. A prescription for setting up the initial beam appropriate to modeling 2-D (continuous) beams has also been developed. The new models for (2) are described in this paper, selected comparisons with other calculations are presented, and a beamline application is summarized. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 GH Gillespie Associates Inc, Del Mar, CA 92014 USA. LLNL, Ctr Accelerator Mass Spectrometry, Livermore, CA 94551 USA. RP Gillespie, GH (reprint author), GH Gillespie Associates Inc, POB 2961, Del Mar, CA 92014 USA. NR 10 TC 6 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 11 PY 1999 VL 427 IS 1-2 BP 315 EP 320 DI 10.1016/S0168-9002(98)01543-5 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 202XV UT WOS:000080678200058 ER PT J AU Yao, S Anex, DS Caldwell, WB Arnold, DW Smith, KB Schultz, PG AF Yao, S Anex, DS Caldwell, WB Arnold, DW Smith, KB Schultz, PG TI SDS capillary gel electrophoresis of proteins in microfabricated channels SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID SYSTEMS; PERFORMANCE; PROTEOMICS; TECHNOLOGY; CHIP AB Analysis of variations in the concentrations or structures of biomolecules (e.g., mRNAs, proteins, peptides, natural products) that occur either naturally or in response to environmental or genetic perturbations can provide important insight into complex biological processes. Many biological samples are mixtures that require a separation step before quantitation of variations in the individual components. Two-dimensional denaturing gel electrophoresis has been used very effectively to separate complex mixtures of proteins, but it is time consuming and requires considerable amounts of sample, Microchannel-based separations have proven very effective in rapidly separating small amounts of nucleic acids; more recently, isoelectric focusing of proteins also has been adapted to the microchannel format. Here, we describe microchannel-based SDS capillary gel electrophoresis of proteins and demonstrate the speed and high resolution it provides. This development is an important step toward the miniaturization and integration of multidimensional and array separation methods for complex protein mixtures. C1 Sandia Natl Labs, Livermore, CA 94551 USA. Scripps Res Inst, Dept Chem, La Jolla, CA 92037 USA. RP Schultz, PG (reprint author), Univ Calif Berkeley, Dept Chem, 824 Latimer Hall, Berkeley, CA 94720 USA. RI Yao, Shao/B-8825-2008 NR 27 TC 107 Z9 112 U1 1 U2 14 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD MAY 11 PY 1999 VL 96 IS 10 BP 5372 EP 5377 DI 10.1073/pnas.96.10.5372 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 195JG UT WOS:000080246500012 PM 10318890 ER PT J AU Colella, P Trebotich, DP AF Colella, P Trebotich, DP TI Numerical simulation of incompressible viscous flow in deforming domains SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID NAVIER-STOKES EQUATIONS; PROJECTION METHOD AB We present a second-order accurate finite difference method for numerical solution of the incompressible Navier-Stokes equations in deforming domains. Our approach is a generalization of the Bell-Colella-Glaz predictor-corrector method for incompressible flow. In order to treat the time-dependence and inhomogeneities in the incompressibility constraint introduced by presence of deforming boundaries, we introduce a nontrivial splitting of the velocity field into vortical and potential components to eliminate the inhomogeneous terms in the constraint and a generalization of the Bell-Colella-Glaz algorithm to treat time-dependent constraints. The method is second-order accurate in space and time, has a time step constraint determined by the advective Colella-Friedrichs-Lewy condition, and requires the solution of well behaved linear systems amenable to the use of fast iterative methods. We demonstrate the method on the specific example of viscous incompressible flow in an axisymmetric deforming tube. C1 Lawrence Berkeley Lab, Appl Numer Algorithms Grp, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mech Engn, Berkeley, CA 94720 USA. RP Colella, P (reprint author), Lawrence Berkeley Lab, Appl Numer Algorithms Grp, Berkeley, CA 94720 USA. NR 16 TC 5 Z9 5 U1 0 U2 0 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD MAY 11 PY 1999 VL 96 IS 10 BP 5378 EP 5381 DI 10.1073/pnas.96.10.5378 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 195JG UT WOS:000080246500013 PM 10318891 ER PT J AU Campbell, IH Smith, DL Neef, CJ Ferraris, JP AF Campbell, IH Smith, DL Neef, CJ Ferraris, JP TI Consistent time-of-flight mobility measurements and polymer light-emitting diode current-voltage characteristics SO APPLIED PHYSICS LETTERS LA English DT Article ID LIMITED CONDUCTION; CHARGE INJECTION; THIN-FILMS; DEVICES; TRANSPORT; ELECTROLUMINESCENCE AB We present time-of-flight mobility measurements and measured and calculated current-voltage (I-V) characteristics of structures fabricated using a soluble poly(p-phenylene vinylene) derivative. Time-of-flight measurements were used to determine the electric field dependent hole mobility. This mobility was then used, without adjustable parameters, to calculate the I-V characteristics of space-charge-limited, hole only devices. The measured and calculated I-V characteristics are in good agreement over five orders of magnitude in current. These results demonstrate that an electric field dependent mobility, without invoking trapping effects, provides an accurate description of hole transport in this polymer. (C) 1999 American Institute of Physics. [S0003-6951(99)00419-2]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Texas, Richardson, TX 75083 USA. RP Campbell, IH (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 19 TC 128 Z9 128 U1 3 U2 16 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 10 PY 1999 VL 74 IS 19 BP 2809 EP 2811 DI 10.1063/1.124021 PG 3 WC Physics, Applied SC Physics GA 193TH UT WOS:000080152700025 ER PT J AU Kwon, D Kaplar, RJ Ringel, SA Allerman, AA Kurtz, SR Jones, ED AF Kwon, D Kaplar, RJ Ringel, SA Allerman, AA Kurtz, SR Jones, ED TI Deep levels in p-type InGaAsN lattice matched to GaAs SO APPLIED PHYSICS LETTERS LA English DT Article ID CHEMICAL-VAPOR-DEPOSITION; WAVELENGTH LASER-DIODES; BEAM EPITAXY; GAINNAS AB Deep-level transient spectroscopy measurements were utilized to investigate deep-level defects in metal-organic chemical vapor deposition-grown, unintentionally doped p-type InGaAsN films lattice matched to GaAs. The as-grown material displayed a high concentration of deep levels distributed within the band gap, with a dominant hole trap at E-v +0.10 eV. Postgrowth annealing simplified the deep-level spectra, enabling the identification of three distinct hole traps at 0.10, 0.23, and 0.48 eV above the valence-band edge, with concentrations of 3.5X10(14), 3.8X10(14), and 8.2X10(14) cm(-3), respectively. A direct comparison between the as-grown and annealed spectra revealed the presence of an additional midgap hole trap, with a concentration of 4X10(14) cm(-3) in the as-grown material. The concentration of this trap is sharply reduced by annealing, which correlates with improved material quality and minority-carrier properties after annealing. Of the four hole traps detected, only the 0.48 eV level is not influenced by annealing, suggesting this level may be important for processed InGaAsN devices in the future. (C) 1999 American Institute of Physics. [S0003-6951(99)05119-0]. C1 Ohio State Univ, Dept Elect Engn, Columbus, OH 43210 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Kwon, D (reprint author), Ohio State Univ, Dept Elect Engn, Columbus, OH 43210 USA. NR 13 TC 78 Z9 78 U1 0 U2 12 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 10 PY 1999 VL 74 IS 19 BP 2830 EP 2832 DI 10.1063/1.124028 PG 3 WC Physics, Applied SC Physics GA 193TH UT WOS:000080152700032 ER PT J AU Hui, L AF Hui, L TI Recovery of the shape of the mass power spectrum from the Ly alpha forest SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : theory; intergalactic medium; large-scale structure of universe; quasars : absorption lines ID REDSHIFT-SPACE; INTERGALACTIC MEDIUM; FLUCTUATIONS; DISTORTIONS; REAL AB We propose a method for recovering the shape of the mass power spectrum on large scales from the transmission fluctuations of the Ly alpha forest that directly takes into account redshift-space distortions. The procedure, in discretized form, involves the inversion of a triangular matrix that projects the mass power spectrum in three-dimensional real space to the transmission power spectrum in one-dimensional redshift space. We illustrate the method by performing a linear calculation relating the two. A method that does not take into account redshift-space anisotropy tends to underestimate the steepness of the mass power spectrum in the case of linear distortions. The issue of the effective bias factor for the linear distortion kernel is discussed. C1 Fermi Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. RP Hui, L (reprint author), Fermi Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, POB 500, Batavia, IL 60510 USA. NR 25 TC 35 Z9 35 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 1999 VL 516 IS 2 BP 519 EP 526 DI 10.1086/307134 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 205FQ UT WOS:000080811000002 ER PT J AU Woosley, SE Eastman, RG Schmidt, BP AF Woosley, SE Eastman, RG Schmidt, BP TI Gamma-ray bursts and Type Ic supernova SN 1998bw SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts; stars : evolution; supernovae : individual (SN 1998bw) ID 25 APRIL 1998; MODELS; STARS; EMISSION; SN-1993J; IB AB Recently a Type Ic supernova, SN 1998bw, was discovered coincident with a gamma-ray burst, GRB 980425. The supernova had unusual radio, optical, and spectroscopic properties. Among other things, it was especially bright for a Type Ic both optically and in the radio, and it rose quickly to maximum. We explore here models based upon helium stars in the range 9-14 M-. and carbon-oxygen stars 6-11 M-., which experience unusually energetic explosions (kinetic energy 0.5-2.8 x 10(52) ergs). Bolometric light curves and multiband photometry are calculated and compared favorably with observations. No spectroscopic data are available at this time, but both LTE and non-LTE spectra are calculated for the model that agrees best with the light curve, a carbon-oxygen core of 6 M-. exploded with a kinetic energy of 2.2 x 10(52) ergs. We also examine potential mechanisms for producing the observed gamma-ray burst (GRB)-shock breakout and relativistic shock deceleration in circumstellar material. For spherically symmetric models, both fail to produce a GRB of even the low luminosity inferred for GRB 980425. However, the high explosion energies required to understand the supernova are in contrast to what is expected for such massive stars and indicate that a new sort of explosion may have been identified, possibly the consequence of a collapsar. Indeed a more likely explanation for what was seen is a highly asymmetric explosion in which the GRB was produced by mildly relativistic matter (Gamma approximate to 5) running into circumstellar matter along the line of sight to the Earth. The explosion itself was powered by black hole accretion and jets, but unlike "ordinary" gamma-ray bursts, the jets were not of sufficient energy and duration to effectively reach large values of Gamma. They may also not have been oriented in our direction. The ejected mass (but not the Ni-56 mass) and explosion energy are then smaller. Other associations between luminous Type Ic supernovae and GRBs may exist and should be sought, but most Type Ib and Type Ic supernovae do not make GRBs. C1 Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Australian Natl Univ, Mt Stromlo & Siding Spring Observ, Canberra, ACT, Australia. RP Woosley, SE (reprint author), Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA. OI Schmidt, Brian/0000-0001-6589-1287 NR 48 TC 248 Z9 250 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 1999 VL 516 IS 2 BP 788 EP 796 DI 10.1086/307131 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 205FQ UT WOS:000080811000025 ER PT J AU Fryer, C Benz, W Herant, M Colgate, SA AF Fryer, C Benz, W Herant, M Colgate, SA TI What can the accretion-induced collapse of white dwarfs really explain? SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; pulsars : general; stars : abundances; stars : neutron; white dwarfs ID GAMMA-RAY BURSTS; I SUPER-NOVAE; MILLISECOND PULSARS; NEUTRON-STARS; GLOBULAR-CLUSTERS; EVOLUTION; EQUATION; MODELS; STATE; BINARY AB The accretion-induced collapse (AIC) of a white dwarf into a. neutron star has been invoked to explain gamma-ray bursts, Type Ia supernovae, and a number of problematic neutron star populations and specific binary systems. The ejecta from this collapse has also been claimed as a source of r-process nucleosynthesis. So far, most AIC studies have focused on determining the event rates from binary evolution models and less attention has been directed toward understanding the collapse itself. However, the collapse of a white dwarf into a neutron star is followed by the ejection of rare neutron-rich isotopes. The observed abundance of these chemical elements may set a more reliable limit on the rate at which AICs have taken place over the history of the Galaxy. In this paper, we present a thorough study of the collapse of a massive white dwarf in one- and two-dimensions and determine the amount and composition of the ejected material. We discuss the importance of the input physics (equation of state, neutrino transport, rotation) in determining these quantities. These simulations affirm that AICs are too baryon rich to produce gamma-ray bursts and do not eject enough nickel to explain Type Ia supernovae (with the possible exception of a small subclass of extremely low-luminosity Type las). Although nucleosynthesis constraints limit the number of neutron stars formed via AICs to less than or similar to 0.1% of the total Galactic neutron star population, AICs remain a viable scenario for forming systems of neutron stars that are difficult to explain with Type II core-collapse supernovae. C1 Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95064 USA. Univ Bern, Inst Phys, CH-3012 Bern, Switzerland. Washington Univ, Sch Med, St Louis, MO 63110 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Fryer, C (reprint author), Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95064 USA. NR 52 TC 110 Z9 110 U1 1 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 1999 VL 516 IS 2 BP 892 EP 899 DI 10.1086/307119 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 205FQ UT WOS:000080811000034 ER PT J AU Kingdon, JB Ferland, GJ AF Kingdon, JB Ferland, GJ TI The effects of charge transfer on the thermal equilibrium of photoionized nebulae SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic data; atomic processes ID HYDROGEN; COLLISIONS; ATOMS; H+ AB Charge transfer can affect both the ionization and thermal balance of astrophysical plasmas. Using the most recent rate coefficients and energy defects, we calculate the heating/cooling rates for charge transfer reactions between hydrogen and elements up to Z = 30. We incorporate these values into the photoionization code CLOUDY. Results from models approximating a wide range of astrophysical objects and conditions suggest that charge transfer can make a significant contribution to the heating near the H ionization front, particularly in objects with a hard ionizing continuum or enhanced abundances. Charge transfer heating can also be important in regimes in which the usual heating/cooling agents are suppressed, such as the emission-line clouds near quasars. We list those reactions that are most important for determining the thermal balance, in the hopes of facilitating improved atomic data. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. RP Kingdon, JB (reprint author), Oak Ridge Natl Lab, Div Phys, POB 2008, Oak Ridge, TN 37831 USA. OI Ferland, Gary/0000-0003-4503-6333 NR 17 TC 33 Z9 33 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 1999 VL 516 IS 2 BP L107 EP L109 DI 10.1086/312008 PN 2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 205FV UT WOS:000080811400015 ER PT J AU Moehs, DP Church, DA AF Moehs, DP Church, DA TI Measured level lifetimes for the coronal transitions of Fe X and Fe XIV SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic data; Sun : corona; techniques : spectroscopic ID IONS; PROBABILITIES; SCHEME AB In a laboratory study, the lifetimes of the P-2 levels producing the coronal transitions of Fe X and Fe XIV have been measured. The fluorescence from the metastable levels, which were populated when the ions were produced in a source of multiply charged ions, was studied after the selected ions were injected into an electrostatic ion trap. The results are tau(Fe X, 3s(2)3p(5) P-2(1/2)o) = 13.64 +/- 0.25 ms and tau(Fe XIV, 3s(2)3p P-2(3/2)o) = 17.52 +/- 0.29 ms. The data significantly reduce the uncertainty of the lifetimes when compared with existing theory. C1 Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. RP Moehs, DP (reprint author), Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. NR 14 TC 24 Z9 24 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 1999 VL 516 IS 2 BP L111 EP L113 DI 10.1086/312006 PN 2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 205FV UT WOS:000080811400016 ER PT J AU 't Zand, JJMI Heise, J Van Paradijs, J Fenimore, EE AF 't Zand, JJMI Heise, J Van Paradijs, J Fenimore, EE TI The prompt X-ray emission of gamma-ray burst 980519 SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma-rays : bursts; X-rays : general ID 28 FEBRUARY 1997; ERROR BOX; AFTERGLOW; BEPPOSAX; GALAXY; BATSE AB The prompt X-ray emission from gamma-ray burst (GRB) 980519, as measured with the Wide Field Cameras on board BeppoSAX, is characterized by a strong soft-to-hard-to-soft evolution. An analysis of the evolution of the X-ray spectrum in terms of a single power-law model shows that the photon index evolved from -2.0 to -1.1 to -2.4. The onset of the burst has such a soft spectrum that the 2-27 keV emission appears to precede the greater than or similar to 107 keV emission of GRB 980519 (as measured with the Burst and Transient Source Experiment) by about 70 s, Nevertheless, we show that this early spectral variation is part of a smooth evolution over the whole burst and that there is no convincing evidence that the early X-rays originate from a physical process that is different from that giving rise to the remainder of the burst. C1 Space Res Org Netherlands, NL-3584 CA Utrecht, Netherlands. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Ctr High Energy Astrophys, NL-1098 SJ Amsterdam, Netherlands. Univ Alabama, Dept Phys, Huntsville, AL 35899 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP 't Zand, JJMI (reprint author), Space Res Org Netherlands, Sorbonnelaan 2, NL-3584 CA Utrecht, Netherlands. NR 37 TC 22 Z9 22 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 1999 VL 516 IS 2 BP L57 EP L60 DI 10.1086/312002 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 205FV UT WOS:000080811400003 ER PT J AU Richardson, JD Cruse, TA AF Richardson, JD Cruse, TA TI Weakly singular stress-BEM for 2D elastostatics SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING LA English DT Article DE boundary element method; elasticity; hypersingular; regularization; interpolation order ID BOUNDARY INTEGRAL-EQUATIONS; ELASTICITY; ELEMENTS; REGULARIZATION AB A weakly singular stress-BEM is presented in which the linear state regularizing field is extended over the entire surface. The algorithm employs standard conforming CO elements with Lagrangian interpolations and exclusively uses Gaussian integration without any transformation of the integrands other than the usual mapping into the intrinsic space. The linear state stress-BIE on which the algorithm is based has no free term so that the BEM treatment of external corners requires no special consideration other than to admit traction discontinuities. The self-regularizing nature of the Somigliana stress identity is demonstrated to produce a very simple and effective method for computing stresses which gives excellent numerical results for all points in the body including boundary points and interior points which may be arbitrarily close to a boundary. A key observation is the relation between BIE density functions and successful interpolation orders. Numerical results for two dimensions show that the use of quartic interpolations is required for algorithms employing regularization over an entire surface to show comparable accuracy to algorithms using local regularization and quadratic interpolations. Additionally, the numerical results show that there is no general correlation between discontinuities in elemental displacement gradients and solution accuracy either in terms of unknown boundary data or interior solutions near element junctions. (C) 1999 John Wiley & Sons, Ltd. C1 Vanderbilt Univ, Dept Engn Mech, Nashville, TN 37235 USA. RP Richardson, JD (reprint author), Oak Ridge Natl Lab, Div Math & Comp Sci, Oak Ridge, TN 37831 USA. NR 21 TC 29 Z9 29 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0029-5981 J9 INT J NUMER METH ENG JI Int. J. Numer. Methods Eng. PD MAY 10 PY 1999 VL 45 IS 1 BP 13 EP 35 DI 10.1002/(SICI)1097-0207(19990510)45:1<13::AID-NME576>3.0.CO;2-W PG 23 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA 186BR UT WOS:000079707400002 ER PT J AU Knupp, PM AF Knupp, PM TI Applications of mesh smoothing: Copy, morph, and sweep on unstructured quadrilateral meshes SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING LA English DT Article DE unstructured grid generation; hexahedral meshing; mesh smoothing; mesh sweeping; mesh copying ID GRID GENERATION AB Mesh smoothing is demonstrated to be an effective means of copying, morphing, and sweeping unstructured quadrilateral surface meshes from a source surface to a target surface. Construction of the smoother in a particular way guarantees that the target mesh will be a 'copy' of the source mesh, provided the boundary data of the target surface is a rigid body rotation, translation, and/or uniform scaling of the original source boundary data and provided the proper boundary node correspondence between source and target has been selected. Copying is not restricted to any particular smoother, but can be based on any locally elliptic second-order operator. When the bounding loops are more general than rigid body transformations the method generates high-quality, 'morphed' meshes. Mesh sweeping, if viewed as a morphing of the source surface to a set of target surfaces, can be effectively performed via this smoothing algorithm. Published in 1999 by John Wiley & Sons, Ltd. This article is a U.S, government work and is in the public domain in the United States. C1 Sandia Natl Labs, Parallel Comp Sci Dept, Albuquerque, NM 87185 USA. RP Knupp, PM (reprint author), Sandia Natl Labs, Parallel Comp Sci Dept, POB 5800,MS 0441, Albuquerque, NM 87185 USA. NR 15 TC 19 Z9 22 U1 0 U2 3 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0029-5981 J9 INT J NUMER METH ENG JI Int. J. Numer. Methods Eng. PD MAY 10 PY 1999 VL 45 IS 1 BP 37 EP 45 DI 10.1002/(SICI)1097-0207(19990510)45:1<37::AID-NME577>3.0.CO;2-F PG 9 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA 186BR UT WOS:000079707400003 ER PT J AU Sammis, CG Nadeau, RM Johnson, LR AF Sammis, CG Nadeau, RM Johnson, LR TI How strong is an asperity? SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID 1984 MORGAN-HILL; FAULT-ZONE; REPEATING EARTHQUAKES; RUPTURE HISTORY; STRESS DROP; HEAT-FLOW; CALIFORNIA; PARKFIELD; INVERSION; MOTION AB A recent study of repeating earthquakes on the San Andreas Fault in central California by Nadeau and Johnson [1998] found that the smallest events occurred on patches having a linear dimension of the order of 0.5 m, displacements of about 2 cm, and stress drops of the order of 2000 MPa, roughly 10 times larger than rock strengths measured in the laboratory. The stress drop for larger events was observed to decrease as a power law of the seismic moment reaching the commonly observed value of 10 MPa at about magnitude 6. These large strengths are shown here to be consistent with laboratory data if the preexisting microcracks are all healed. A hierarchical fractal asperity model is presented, which is based on recent laboratory observations of contact distributions in sliding friction experiments. This "Cantor dust" model is shown to be consistent with the observed power law decrease in stress drop and increase in displacement with increasing event size. The spatial distribution of hypocenters in the Parkfield area is shown to be consistent with this simple fractal model and with a hierarchical clustering of asperities having a fractal dimension of D=1 and discrete rescaling factor of about 20. C1 Univ So Calif, Dept Earth Sci, Los Angeles, CA 90089 USA. Univ Calif Berkeley, Ctr Computat Seismol, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Seismog Stn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Berkeley Seismol Lab, Berkeley, CA 94720 USA. RP Sammis, CG (reprint author), Univ So Calif, Dept Earth Sci, Los Angeles, CA 90089 USA. EM sammis@earth.usc.edu; nadeau@ccs.lbl.gov; lrj@ccs.lbl.gov NR 46 TC 34 Z9 34 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD MAY 10 PY 1999 VL 104 IS B5 BP 10609 EP 10619 DI 10.1029/1999JB900006 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 194PD UT WOS:000080202000014 ER PT J AU Achucarro, A Borrill, J Liddle, AR AF Achucarro, A Borrill, J Liddle, AR TI Formation rate of semilocal strings SO PHYSICAL REVIEW LETTERS LA English DT Article ID COSMIC STRINGS; ELECTROWEAK STRINGS; TOPOLOGICAL DEFECTS; EVOLUTION AB We carry out three-dimensional numerical simulations to investigate the formation rate of semilocal strings. We find that the backreaction of the gauge fields on the scalar field evolution is substantial, and leads to a significant formation rate in the parameter regime where the semilocal strings are classically stable. The formation rate can be as large as one-third of that for cosmic strings, depending on the model parameters. C1 Univ Basque Country, Dept Theoret Phys, Bilbao, Spain. Univ Groningen, Inst Theoret Phys, NL-9700 AB Groningen, Netherlands. Univ Calif Berkeley, Ctr Particle Astrophys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Natl Energy Res Sci Comp Ctr, Berkeley, CA 94720 USA. Univ Sussex, Ctr Astron, Brighton BN1 9QJ, E Sussex, England. RP Achucarro, A (reprint author), Univ Basque Country, Dept Theoret Phys, Bilbao, Spain. NR 20 TC 27 Z9 27 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 10 PY 1999 VL 82 IS 19 BP 3742 EP 3745 DI 10.1103/PhysRevLett.82.3742 PG 4 WC Physics, Multidisciplinary SC Physics GA 194RN UT WOS:000080207500004 ER PT J AU Bartelt, J Csorna, SE McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S Bonvicini, G Cinabro, D Greene, R Perera, LP Zhou, GJ Chan, S Eigen, G Lipeles, E Miller, JS Schmidtler, M Shapiro, A Sun, WM Urheim, J Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Gronberg, J Hill, TS Lange, DJ Morrison, RJ Nelson, HN Nelson, TK Roberts, D Behrens, BH Ford, WT Gritsan, A Krieg, H Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Boisvert, V Cassel, DG Crowcroft, DS Dickson, M von Dombrowski, S Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kandaswamy, J Kreinick, DL Lee, T Liu, Y Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Valant-Spaight, B Warburton, A Ward, C Athanas, M Avery, P Jones, CD Lohner, M Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Briere, RA Ershov, A Gao, YS Kim, DYJ Wilson, R Yamamoto, H Browder, TE Li, Y Rodriguez, JL Sahu, SK Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Selen, M Thaler, JJ Edwards, KW Bellerive, A Janicek, R Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Darling, C Davis, R Kotov, S Kravchenko, I Kwak, N Zhou, L Anderson, S Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Hart, T Honscheid, K Kagan, H Kass, R Lee, J Schwarthoff, H Wolf, A Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Bishai, M Chen, S Fast, J Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ Glenn, S Kwon, Y Lyon, AL Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T Artuso, M Dambasuren, E Kopp, S Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Titov, A Viehhauser, G Wang, JC AF Bartelt, J Csorna, SE McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S Bonvicini, G Cinabro, D Greene, R Perera, LP Zhou, GJ Chan, S Eigen, G Lipeles, E Miller, JS Schmidtler, M Shapiro, A Sun, WM Urheim, J Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Gronberg, J Hill, TS Lange, DJ Morrison, RJ Nelson, HN Nelson, TK Roberts, D Behrens, BH Ford, WT Gritsan, A Krieg, H Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Boisvert, V Cassel, DG Crowcroft, DS Dickson, M von Dombrowski, S Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kandaswamy, J Kreinick, DL Lee, T Liu, Y Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Valant-Spaight, B Warburton, A Ward, C Athanas, M Avery, P Jones, CD Lohner, M Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Briere, RA Ershov, A Gao, YS Kim, DYJ Wilson, R Yamamoto, H Browder, TE Li, Y Rodriguez, JL Sahu, SK Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Selen, M Thaler, JJ Edwards, KW Bellerive, A Janicek, R Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Darling, C Davis, R Kotov, S Kravchenko, I Kwak, N Zhou, L Anderson, S Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Hart, T Honscheid, K Kagan, H Kass, R Lee, J Schwarthoff, H Wolf, A Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Bishai, M Chen, S Fast, J Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ Glenn, S Kwon, Y Lyon, AL Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T Artuso, M Dambasuren, E Kopp, S Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Titov, A Viehhauser, G Wang, JC TI Measurement of the B -> Dl nu branching fractions and form factor SO PHYSICAL REVIEW LETTERS LA English DT Article ID DISPERSIVE BOUNDS; MESON DECAYS; HEAVY MESONS; QUARK-MODEL AB Using a sample of 3.3 x 10(6) B-meson decays collected with the CLEO detector at the Cornell Electron Storage Ring, we have studied B- --> D(0)l(-)<(nu)over bar> and (B) over bar(0) --> D(+)l(-)<(nu)over bar> decays, where l(-) can be either e(-) or mu(-). We distinguish B --> Dl nu from other B semileptonic decays by examining the net momentum and energy of the particles recoiling against D - l pairs. We find Gamma(B --> Dl nu) = (14.1 +/- 1.0 +/- 1.2) ns(-1) and derive branching fractions for B- --> D(0)l(-)<(nu)over bar> and (B) over bar(0) --> D(+)l(-)<(nu)over bar> of (2.32 +/- 0.17 +/- 0.20)% and (2.20 +/- 0.16 +/- 0.19)%, respectively, where the uncertainties are statistical and systematic. We also investigate the B --> Dl nu form factor and the implication of the result for \V-cb\. C1 Vanderbilt Univ, Nashville, TN 37235 USA. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. Wayne State Univ, Detroit, MI 48202 USA. CALTECH, Pasadena, CA 91125 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. Univ Colorado, Boulder, CO 80309 USA. Cornell Univ, Ithaca, NY 14853 USA. Univ Florida, Gainesville, FL 32611 USA. Harvard Univ, Cambridge, MA 02138 USA. Univ Hawaii Manoa, Honolulu, HI 96822 USA. Univ Illinois, Urbana, IL 61801 USA. Carleton Univ, Ottawa, ON K1S 5B6, Canada. Inst Particle Phys, Montreal, PQ, Canada. McGill Univ, Montreal, PQ H3A 2T8, Canada. Ithaca Coll, Ithaca, NY 14850 USA. Univ Kansas, Lawrence, KS 66045 USA. Univ Minnesota, Minneapolis, MN 55455 USA. SUNY Albany, Albany, NY 12222 USA. Ohio State Univ, Columbus, OH 43210 USA. Univ Oklahoma, Norman, OK 73019 USA. Purdue Univ, W Lafayette, IN 47907 USA. Univ Rochester, Rochester, NY 14627 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. So Methodist Univ, Dallas, TX 75275 USA. Syracuse Univ, Syracuse, NY 13244 USA. Univ Cincinnati, Cincinnati, OH 45221 USA. Univ Texas, Austin, TX 78712 USA. Yonsei Univ, Seoul 120749, South Korea. RP Bartelt, J (reprint author), Vanderbilt Univ, 221 Kirkland Hall, Nashville, TN 37235 USA. RI Warburton, Andreas/N-8028-2013; Briere, Roy/N-7819-2014 OI Warburton, Andreas/0000-0002-2298-7315; Briere, Roy/0000-0001-5229-1039 NR 23 TC 44 Z9 44 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 10 PY 1999 VL 82 IS 19 BP 3746 EP 3750 DI 10.1103/PhysRevLett.82.3746 PG 5 WC Physics, Multidisciplinary SC Physics GA 194RN UT WOS:000080207500005 ER PT J AU Affolder, A Alavi-Harati, A Albuquerque, IF Alexopoulos, T Arenton, M Arisaka, K Averitte, S Barker, AR Bellantoni, L Bellavance, A Belz, J Ben-David, R Bergman, DR Blucher, E Bock, GJ Bown, C Bright, S Cheu, E Childress, S Coleman, R Corcoran, MD Corti, G Cox, B Crisler, MB Erwin, AR Ford, R Golossanov, A Graham, G Graham, J Hagan, K Halkiadakis, E Hanagaki, K Hidaka, S Hsiung, YB Jejer, V Jennings, J Jensen, DA Kessler, R Kobrak, HGE LaDue, J Lath, A Ledovskoy, A McBride, PL McManus, AP Mikelsons, P Monnier, E Nakaya, T Nauenberg, U Nelson, KS Nguyen, H O'Dell, V Pang, M Pordes, R Prasad, V Qiao, C Quinn, B Ramberg, EJ Ray, RE Roodman, A Sadamoto, M Schnetzer, S Senyo, K Shanahan, P Shawhan, PS Slater, W Solomey, N Somalwar, SV Stone, RL Suzuki, I Swallow, EC Swanson, RA Taegar, SA Tesarek, RJ Thomson, GB Toale, PA Tripathi, A Tschirhart, R Wah, YW Wang, J White, HB Whitmore, J Winstein, B Winston, R Wu, JY Yamanaka, T Zimmerman, ED AF Affolder, A Alavi-Harati, A Albuquerque, IF Alexopoulos, T Arenton, M Arisaka, K Averitte, S Barker, AR Bellantoni, L Bellavance, A Belz, J Ben-David, R Bergman, DR Blucher, E Bock, GJ Bown, C Bright, S Cheu, E Childress, S Coleman, R Corcoran, MD Corti, G Cox, B Crisler, MB Erwin, AR Ford, R Golossanov, A Graham, G Graham, J Hagan, K Halkiadakis, E Hanagaki, K Hidaka, S Hsiung, YB Jejer, V Jennings, J Jensen, DA Kessler, R Kobrak, HGE LaDue, J Lath, A Ledovskoy, A McBride, PL McManus, AP Mikelsons, P Monnier, E Nakaya, T Nauenberg, U Nelson, KS Nguyen, H O'Dell, V Pang, M Pordes, R Prasad, V Qiao, C Quinn, B Ramberg, EJ Ray, RE Roodman, A Sadamoto, M Schnetzer, S Senyo, K Shanahan, P Shawhan, PS Slater, W Solomey, N Somalwar, SV Stone, RL Suzuki, I Swallow, EC Swanson, RA Taegar, SA Tesarek, RJ Thomson, GB Toale, PA Tripathi, A Tschirhart, R Wah, YW Wang, J White, HB Whitmore, J Winstein, B Winston, R Wu, JY Yamanaka, T Zimmerman, ED TI Observation of the decay Xi(0)->Sigma(+)e(-)(nu)over-bar-(e) SO PHYSICAL REVIEW LETTERS LA English DT Article ID HYPERON SEMILEPTONIC DECAYS; SU(3) SYMMETRY-BREAKING AB We present the first observation of Xi(0) beta decay, using the KTeV beam line and detector at Fermilab. We have identified 176 beta decay events after subtracting a 7 event background. Normalization to 41024 simultaneously collected Xi(0) --> Lambda(0)pi(0) decays yields a branching ratio of Gamma(Xi(0) --> Sigma(+) e(-)<(nu)over bar>(e))/Gamma(total) = (2.71 +/- 0.22(statistical) +/- 0.31(systematic)) X 10(-4). The flavor symmetric quark model calculation agrees with this result. C1 Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Univ Arizona, Tucson, AZ 85721 USA. Univ Calif Los Angeles, Los Angeles, CA 90095 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Colorado, Boulder, CO 80309 USA. Elmhurst Coll, Elmhurst, IL 60126 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Osaka Univ, Toyonaka, Osaka 560, Japan. Rice Univ, Houston, TX 77005 USA. Rutgers State Univ, Piscataway, NJ 08855 USA. Univ Virginia, Dept Phys, Charlottesville, VA 22901 USA. Univ Virginia, Inst Nucl & Particle Phys, Charlottesville, VA 22901 USA. Univ Wisconsin, Madison, WI 53706 USA. RP Monnier, E (reprint author), Univ Chicago, Enrico Fermi Inst, 5640 S Ellis Ave, Chicago, IL 60637 USA. RI Albuquerque, Ivone/H-4645-2012 OI Albuquerque, Ivone/0000-0001-7328-0136 NR 15 TC 21 Z9 21 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 10 PY 1999 VL 82 IS 19 BP 3751 EP 3754 DI 10.1103/PhysRevLett.82.3751 PG 4 WC Physics, Multidisciplinary SC Physics GA 194RN UT WOS:000080207500006 ER PT J AU Bouwhuis, M Alarcon, R Botto, T van den Brand, JFJ Bulten, HJ Dolfini, S Ent, R Ferro-Luzzi, M Higinbotham, DW de Jager, CW Lang, J de Lange, DJJ Papadakis, N Passchier, I Poolman, HR Six, E Steijger, JJM Vodinas, N de Vries, H Zhou, ZL AF Bouwhuis, M Alarcon, R Botto, T van den Brand, JFJ Bulten, HJ Dolfini, S Ent, R Ferro-Luzzi, M Higinbotham, DW de Jager, CW Lang, J de Lange, DJJ Papadakis, N Passchier, I Poolman, HR Six, E Steijger, JJM Vodinas, N de Vries, H Zhou, ZL TI Measurement of T-20 in elastic electron-deuteron scattering SO PHYSICAL REVIEW LETTERS LA English DT Article ID POLARIZED INTERNAL TARGETS; ION-EXTRACTION POLARIMETRY; TENSOR POLARIZATION; STORAGE-RING; FORM-FACTORS; RANGE AB We report on a measurement of the tensor analyzing power T-20 in elastic electron-deuteron scattering in the range of four-momentum transfer from 1.8 to 3.2 fm(-1). Electrons of 704 MeV were scattered from a polarized deuterium internal target. The tensor polarization of the deuterium nuclei was determined with an ion-extraction system, allowing an absolute measurement of T-20 The data are described well by a nonrelativistic calculation that includes the effects of meson-exchange currents. C1 Natl Inst Kernfys & Hoge Energie Fys, NL-1009 DB Amsterdam, Netherlands. Arizona State Univ, Dept Phys, Tempe, AZ 85287 USA. Free Univ Amsterdam, Dept Phys & Astron, NL-1081 HV Amsterdam, Netherlands. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. Hampton Univ, Dept Phys, Hampton, VA 23668 USA. ETH Zurich, Inst Teilchenphys, CH-8093 Zurich, Switzerland. Univ Virginia, Dept Phys, Charlottesville, VA 22901 USA. RP Bouwhuis, M (reprint author), Natl Inst Kernfys & Hoge Energie Fys, POB 41882, NL-1009 DB Amsterdam, Netherlands. RI Higinbotham, Douglas/J-9394-2014 OI Higinbotham, Douglas/0000-0003-2758-6526 NR 22 TC 66 Z9 66 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 10 PY 1999 VL 82 IS 19 BP 3755 EP 3758 DI 10.1103/PhysRevLett.82.3755 PG 4 WC Physics, Multidisciplinary SC Physics GA 194RN UT WOS:000080207500007 ER PT J AU Rudolph, D Baktash, C Brinkman, MJ Caurier, E Dean, DJ Devlin, M Dobaczewski, J Heenen, PH Jin, HQ LaFosse, DR Nazarewicz, W Nowacki, F Poves, A Riedinger, LL Sarantites, DG Satula, W Yu, CH AF Rudolph, D Baktash, C Brinkman, MJ Caurier, E Dean, DJ Devlin, M Dobaczewski, J Heenen, PH Jin, HQ LaFosse, DR Nazarewicz, W Nowacki, F Poves, A Riedinger, LL Sarantites, DG Satula, W Yu, CH TI Rotational bands in the doubly magic nucleus Ni-56 SO PHYSICAL REVIEW LETTERS LA English DT Article ID DEFORMED HARMONIC-OSCILLATOR; HARTREE-FOCK EQUATIONS; MASS REGION; TERMINATION; SHELL AB Structures of the medium- to high-spin states in the doubly magic nucleus Ni-56 have been investigated using the reaction Si-28(Ar-36, 2 alpha) and the gamma-ray spectrometer Gammasphere in conjunction with the 4 pi charged-particle detector array Microball. Two well-deformed rotational bands have been identified. There is evidence that one of the bands, which is identical to a sequence in the odd-odd neighbor Cu-58, partially decays via proton emission into the ground state of Co-55. Predictions of extensive large-scale shell-model and cranked Hartree-Fock and Hartree-Fock-Bogolyubov calculations are compared with the experimental data. C1 Univ Lund, Dept Phys, S-22100 Lund, Sweden. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Inst Natl Phys Nucl & Phys Particules, CNRS, Inst Rech Subatom, F-67037 Strasbourg, France. Univ Strasbourg 1, F-67037 Strasbourg, France. Univ Lund, Dept Phys, S-22100 Lund, Sweden. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Washington Univ, Dept Chem, St Louis, MO 63130 USA. Univ Warsaw, Inst Theoret Phys, PL-00681 Warsaw, Poland. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Joint Inst Heavy Ion Res, Oak Ridge, TN 37831 USA. ULB, Serv Phys Nucl Theor, B-1050 Brussels, Belgium. Univ Autonoma Madrid, Dept Fis Teor, E-28049 Madrid, Spain. RP Rudolph, D (reprint author), Univ Lund, Dept Phys, S-22100 Lund, Sweden. RI Rudolph, Dirk/D-4259-2009; Poves, Alfredo/L-2594-2013; Devlin, Matthew/B-5089-2013; OI Rudolph, Dirk/0000-0003-1199-3055; Poves, Alfredo/0000-0001-7539-388X; Devlin, Matthew/0000-0002-6948-2154; Dean, David/0000-0002-5688-703X NR 25 TC 140 Z9 140 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 10 PY 1999 VL 82 IS 19 BP 3763 EP 3766 DI 10.1103/PhysRevLett.82.3763 PG 4 WC Physics, Multidisciplinary SC Physics GA 194RN UT WOS:000080207500009 ER PT J AU Wallace, JM Murphy, TJ Delamater, ND Klare, KA Oertel, JA Magelssen, GR Lindman, EL Hauer, AA Gobby, P Schnittman, JD Craxton, RS Seka, W Kremens, R Bradley, D Pollaine, SM Turner, RE Landen, OL Drake, D MacFarlane, JJ AF Wallace, JM Murphy, TJ Delamater, ND Klare, KA Oertel, JA Magelssen, GR Lindman, EL Hauer, AA Gobby, P Schnittman, JD Craxton, RS Seka, W Kremens, R Bradley, D Pollaine, SM Turner, RE Landen, OL Drake, D MacFarlane, JJ TI Inertial confinement fusion with tetrahedral hohlraums at OMEGA SO PHYSICAL REVIEW LETTERS LA English DT Article ID MULTIPLE-BEAM CONES; SYMMETRY EXPERIMENTS; LASER SYSTEM; RADIATION; TARGET; NOVA; PERFORMANCE AB Indirect-drive inertial confinement fusion will require for ignition a highly symmetric x-ray flux around the capsule. To this end, the "tetrahedral hohlraum," spherical in shape with four laser entrance holes located at the vertices of a tetrahedron, has been proposed. The first experimental test of this concept, using the OMEGA laser, is reported here. Drive symmetry was probed using capsule implosion symmetries, which varied qualitatively as expected with hohlraum dimensions. Modeling of the experiments gives time-averaged flux asymmetries as low as 1% rms over a 2.2-ns laser pulse. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Rochester, Laser Energet Lab, Rochester, NY 14623 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Intersci, Germantown, MD 20875 USA. Univ Wisconsin, Madison, WI 53706 USA. RP Wallace, JM (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Schnittman, Jeremy/D-3168-2012; Murphy, Thomas/F-3101-2014 OI Murphy, Thomas/0000-0002-6137-9873 NR 30 TC 27 Z9 28 U1 0 U2 10 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 10 PY 1999 VL 82 IS 19 BP 3807 EP 3810 DI 10.1103/PhysRevLett.82.3807 PG 4 WC Physics, Multidisciplinary SC Physics GA 194RN UT WOS:000080207500020 ER PT J AU Garofalo, AM Turnbull, AD Austin, ME Bialek, J Chu, MS Comer, KJ Fredrickson, ED Groebner, RJ La Haye, RJ Lao, LL Lazarus, EA Navratil, GA Osborne, TH Rice, BW Sabbagh, SA Scoville, JT Strait, EJ Taylor, TS AF Garofalo, AM Turnbull, AD Austin, ME Bialek, J Chu, MS Comer, KJ Fredrickson, ED Groebner, RJ La Haye, RJ Lao, LL Lazarus, EA Navratil, GA Osborne, TH Rice, BW Sabbagh, SA Scoville, JT Strait, EJ Taylor, TS TI Direct observation of the resistive wall mode in a tokamak and its interaction with plasma rotation SO PHYSICAL REVIEW LETTERS LA English DT Article ID HIGH-BETA; DIII-D; STABILIZATION; STABILITY; SHELL; SHEAR AB Using newly developed techniques and improved diagnostics, rotating wall-stabilized discharges have been maintained in the DIII-D tokamak for 30 characteristic resistive wall decay times-significantly longer than was previously achieved. The terminating resistive wall mode has been directly identified using internal fluctuation diagnostics, and its correlation with the slowdown in the plasma rotation is established. C1 Columbia Univ, New York, NY 10027 USA. Gen Atom Co, San Diego, CA 92186 USA. Univ Texas, Austin, TX 78712 USA. Univ Wisconsin, Madison, WI 53706 USA. Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Garofalo, AM (reprint author), Columbia Univ, New York, NY 10027 USA. RI Sabbagh, Steven/C-7142-2011 NR 20 TC 120 Z9 120 U1 1 U2 8 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 10 PY 1999 VL 82 IS 19 BP 3811 EP 3814 DI 10.1103/PhysRevLett.82.3811 PG 4 WC Physics, Multidisciplinary SC Physics GA 194RN UT WOS:000080207500021 ER PT J AU Petkov, MP Weber, MH Lynn, KG Crandall, RS Ghosh, VJ AF Petkov, MP Weber, MH Lynn, KG Crandall, RS Ghosh, VJ TI Direct evidence of phosphorus-defect complexes in n-type amorphous silicon and hydrogenated amorphous silicon SO PHYSICAL REVIEW LETTERS LA English DT Article ID A-SI-H; POSITRON-ANNIHILATION; ELEMENTAL SPECIFICITY; SURFACES; ENERGY AB We use positron annihilation spectroscopy (PAS) to identify the phosphorus-defect complex (*D-) in n-type hydrogenated amorphous Si (a-Si:H). The positrons are attracted and localized at the small open volume associated with the dangling bond defects. The radiation detected after annihilation gives a characteristic P signature, regarded as a *D- "fingerprint." Additional evidence is obtained from a comparison to P-implanted amorphized Si, as well as from theoretical calculations. This work lays the foundation for PAS studies of impurity-defect related processes in a-Si:H. C1 Washington State Univ, Dept Phys, Pullman, WA 99164 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. RP Petkov, MP (reprint author), Washington State Univ, Dept Phys, Pullman, WA 99164 USA. NR 16 TC 23 Z9 23 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 10 PY 1999 VL 82 IS 19 BP 3819 EP 3822 DI 10.1103/PhysRevLett.82.3819 PG 4 WC Physics, Multidisciplinary SC Physics GA 194RN UT WOS:000080207500023 ER PT J AU Lee, GD Wang, CZ Lu, ZY Ho, KM AF Lee, GD Wang, CZ Lu, ZY Ho, KM TI Addimer diffusion along the trough between dimer rows on Si(001) SO SURFACE SCIENCE LA English DT Letter DE density functional calculations; low-index single crystal surfaces; semi-empirical models and model calculations; silicon; surface diffusion ID SI AD-DIMERS; SCANNING-TUNNELING-MICROSCOPY; SI(100) SURFACE; SILICON DIMER; DYNAMICS; NUCLEATION; ROTATION; BINDING AB The diffusion pathways along the trough on the Si(001) surface are investigated by tight-binding molecular dynamics calculations using the environment-dependent tight-binding silicon potential and by ab-initio calculations using the Car-Parrinello method. A new diffusion pathway is discovered, consisting of rotation of the addimer. The energy barrier is calculated to be 1.22 eV per dimer, which is in excellent agreement with the experiment. (C) 1999 Elsevier Science B.V. All rights reserved. C1 US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys, Ames, IA 50011 USA. RP Ho, KM (reprint author), US DOE, Ames Lab, Ames, IA 50011 USA. RI 上官, 敏慧/E-8964-2012; Lee, Gun-Do/L-1259-2013 OI Lee, Gun-Do/0000-0001-8328-8625 NR 13 TC 12 Z9 13 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAY 10 PY 1999 VL 426 IS 2 BP L427 EP L432 DI 10.1016/S0039-6028(99)00350-7 PG 6 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 196PU UT WOS:000080317400001 ER PT J AU Wunderlich, B Boller, A Okazaki, I Ishikiriyama, K Chen, W Pyda, M Pak, J Moon, I Androsch, R AF Wunderlich, B Boller, A Okazaki, I Ishikiriyama, K Chen, W Pyda, M Pak, J Moon, I Androsch, R TI Temperature-modulated differential scanning calorimetry of reversible and irreversible first-order transitions SO THERMOCHIMICA ACTA LA English DT Article; Proceedings Paper CT Vth Lahnwitz Seminar on Calorimetry on Investigation of Phase Transitions by Temperature-Modulated Calorimetry CY JUN 07-12, 1998 CL KUHLUNGSBORN, GERMANY DE temperature-modulated calorimetry; heat capacity; first-order transition; lissajous figures; indium; paraffin; liquid crystal; polymer ID HEAT-CAPACITY; REGION; POLY(ETHYLENE-TEREPHTHALATE); CRYSTALLIZATION; POLYETHYLENE; DSC AB Temperature-modulated differential scanning calorimetry of first-order transitions has led to many new observations. Some of these involve non-linear processes or deal with transformations of practically instantaneous response. The latter may cause serious lags within the calorimeter due to limited thermal conductivity of the sample and the instrument. In both cases the "reversing heat capacity" or a "complex heat capacity" is not a precise representation of the transition since both are computed from abbreviated Fourier transforms, limited to the evaluation of the first harmonic component. One has in these cases to work in the time-domain with the raw output. But even from these analyses in the time-domain many interesting new insights about the transition and the calorimeter performance can be generated. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Wunderlich, B (reprint author), Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. NR 40 TC 69 Z9 69 U1 3 U2 22 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0040-6031 J9 THERMOCHIM ACTA JI Thermochim. Acta PD MAY 10 PY 1999 VL 330 IS 1-2 BP 21 EP 38 DI 10.1016/S0040-6031(99)00037-4 PG 18 WC Thermodynamics; Chemistry, Analytical; Chemistry, Physical SC Thermodynamics; Chemistry GA 205RK UT WOS:000080834200003 ER PT J AU Alagia, M Balucani, N Cartechini, L Casavecchia, P Volpi, GG Pederson, LA Schatz, GC Lendvay, G Harding, LB Hollebeek, T Ho, TS Rabitz, H AF Alagia, M Balucani, N Cartechini, L Casavecchia, P Volpi, GG Pederson, LA Schatz, GC Lendvay, G Harding, LB Hollebeek, T Ho, TS Rabitz, H TI Exploring the reaction dynamics of nitrogen atoms: A combined crossed beam and theoretical study of N(D-2)+D-2 -> ND+D SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID POTENTIAL-ENERGY SURFACES; VIBRATIONAL DISTRIBUTIONS; RADIOFREQUENCY DISCHARGE; COLLISION ENERGIES; CHEMICAL-REACTIONS; MOLECULAR-BEAMS; F+H-2 REACTION; STATE; SCATTERING; RADICALS AB In the first successful reactive scattering study of nitrogen atoms, the angular and velocity distribution of the ND product from the reaction N(D-2) + D-2 at 5.1 and 3.8 kcal/mol collision energies has been obtained in a crossed molecular beam study with mass spectrometric detection. The center-of-mass product angular distribution is found to be nearly backward-forward symmetric, reflecting an insertion dynamics. About 30% of the total available energy goes into product translation. The experimental results were compared with those of quasiclassical trajectory calculations on an accurate potential energy surface obtained from large scale ab initio electronic structure computations. Good agreement was found between the experimental results and the theoretical predictions. (C) 1999 American Institute of Physics. [S0021-9606(99)02118-2]. C1 Univ Perugia, Dipartimento Chim, I-06123 Perugia, Italy. Northwestern Univ, Dept Chem, Evanston, IL 60208 USA. Hungarian Acad Sci, Inst Chem, H-1525 Budapest, Hungary. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Princeton Univ, Dept Chem, Princeton, NJ 08544 USA. RP Alagia, M (reprint author), Univ Perugia, Dipartimento Chim, I-06123 Perugia, Italy. RI Cartechini, Laura/C-6067-2009; Alagia, Michele/C-9405-2012; Balucani, Nadia/B-8211-2011; Casavecchia, Piergiorgio/F-4175-2014; Lendvay, Gyorgy/B-5397-2016 OI Cartechini, Laura/0000-0001-9834-0801; Alagia, Michele/0000-0002-8467-1842; Balucani, Nadia/0000-0001-5121-5683; Casavecchia, Piergiorgio/0000-0003-1934-7891; Lendvay, Gyorgy/0000-0002-2150-0376 NR 57 TC 75 Z9 75 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 8 PY 1999 VL 110 IS 18 BP 8857 EP 8860 DI 10.1063/1.478806 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 192HU UT WOS:000080073200001 ER PT J AU Tomaselli, M Yarger, JL Bruchez, M Havlin, RH deGraw, D Pines, A Alivisatos, AP AF Tomaselli, M Yarger, JL Bruchez, M Havlin, RH deGraw, D Pines, A Alivisatos, AP TI NMR study of InP quantum dots: Surface structure and size effects SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID NUCLEAR-MAGNETIC-RESONANCE; SEMICONDUCTOR NANOCRYSTALS; ROTATING SOLIDS; CHEMICAL-SHIFTS; CLUSTERS AB We report the results of P-31 NMR measurements on trioctylphosphine oxide (TOPO) passivated InP quantum dots. The spectra show distinct surface-capping sites, implying a manifold of crystal-ligand bonding configurations. Two In P-31 surface components are resolved and related to different electronic surroundings. With decreasing particle size the In P-31 core resonance reveals an increasing upfield chemical shift related to the overall size dependence of the InP electronic structure. (C) 1999 American Institute of Physics. [S0021-9606(99)70718-X]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Tomaselli, M (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Bruchez, Marcel/C-2271-2009; Yarger, Jeff/L-8748-2014; Alivisatos , Paul /N-8863-2015 OI Bruchez, Marcel/0000-0002-7370-4848; Yarger, Jeff/0000-0002-7385-5400; Alivisatos , Paul /0000-0001-6895-9048 NR 28 TC 46 Z9 47 U1 2 U2 21 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 8 PY 1999 VL 110 IS 18 BP 8861 EP 8864 DI 10.1063/1.478858 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 192HU UT WOS:000080073200002 ER PT J AU Lopez, MJ Jellinek, J AF Lopez, MJ Jellinek, J TI On the problem of fitting many-body potentials. I. The minimal maximum error scheme and the paradigm of metal systems SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MOLECULAR-DYNAMICS SIMULATIONS; EMBEDDED-ATOM-METHOD; INITIO MONTE-CARLO; TRANSITION-METALS; INTERATOMIC POTENTIALS; CHEMICAL DISORDER; CRYSTALLINE NIZR2; FCC TRANSITION; LI-N; CLUSTERS AB Issues involved in fitting a semiempirical potential, such as the choice of a goodness criterion, selection of fitting quantities (properties), ascription of the degree of importance to the individual members of a fitting set, etc., all of which affect the outcome of a fitting procedure, are addressed and analyzed. The minimal maximum error fitting scheme is implemented to obtain the values of the parameters of the Gupta-type potential for nickel. The subtleties of this potential, one of which is that only four of its five parameters are independent, and their implications are pointed out and discussed. The resulting values of the parameters for nickel are analyzed and compared with those obtained in earlier studies. (C) 1999 American Institute of Physics. [S0021-9606(99)00418-3]. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Lopez, MJ (reprint author), Univ Valladolid, Dept Fis Teor, E-47011 Valladolid, Spain. RI Lopez, Maria/H-2492-2013 OI Lopez, Maria/0000-0001-7698-9327 NR 68 TC 36 Z9 36 U1 1 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 8 PY 1999 VL 110 IS 18 BP 8899 EP 8911 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 192HU UT WOS:000080073200007 ER PT J AU Boldyrev, AI Simons, J Li, X Chen, WW Wang, LS AF Boldyrev, AI Simons, J Li, X Chen, WW Wang, LS TI Combined photoelectron spectroscopy and ab initio study of the hypermetallic Al3C molecule SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID GAUSSIAN-BASIS SETS; ELECTRONIC-STRUCTURE; GREEN-FUNCTION; ALUMINUM CLUSTERS; ORBITAL METHODS; SURFACES; ATOMS; APPROXIMATION; OXIDATION; EXCHANGE AB The chemical structure and bonding of the hypermetallic Al3C and Al3C- species have been studied by photoelectron spectroscopy and ab initio calculations. Al3C- is found to have a planar triangular (D-3h, (1)A(1)') structure (when averaged over zero-point vibrational modes) and Al3C is found to have a triangular distorted planar structure (C-2 upsilon, B-2(2)) with one elongated Al-C bond. Four peaks in the photoelectron spectra of Al3C- were identified at 2.56, 2.69, 3.23, and 4.08 eV. Assignment of the observed features was made on the basis of the ab initio calculations. The experimental adiabatic electron affinity of Al3C was measured to be 2.56 +/- 0.06 eV, compared to 2.47 eV calculated at the CCSD(T)OVGF/6-311 + G(2df) level of theory. The excellent agreement between the calculated and experimental electron affinity, vibrational frequencies, and excitation energies allowed us to completely elucidate the geometrical and electronic structure of the Al3C molecule and its anion. (C) 1999 American Institute of Physics. [S0021-9606(99)01018-1]. C1 Univ Utah, Dept Chem, Salt Lake City, UT 84112 USA. Washington State Univ, Dept Phys, Richland, WA 99352 USA. Pacific NW Lab, WR Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Boldyrev, AI (reprint author), Univ Utah, Dept Chem, Salt Lake City, UT 84112 USA. RI Boldyrev, Alexander/C-5940-2009 OI Boldyrev, Alexander/0000-0002-8277-3669 NR 42 TC 32 Z9 33 U1 1 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 8 PY 1999 VL 110 IS 18 BP 8980 EP 8985 DI 10.1063/1.478816 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 192HU UT WOS:000080073200015 ER PT J AU Pinnaduwage, LA Tav, C McCorkle, DL Ding, WX AF Pinnaduwage, LA Tav, C McCorkle, DL Ding, WX TI Temperature dependence of electron attachment to methylene chloride SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID LOW-ENERGY ELECTRONS; CROSS SECTIONS; PLASMA; DECOMPOSITION; CH2CL2; SWARM; MOLECULES; CHCL3; CCL4; BEAM AB Temperature dependence of dissociative electron attachment to methylene chloride in the electron energy range of 0-10 eV was studied in a high-temperature electron swarm apparatus. The measurements were made using N-2 and Ar as buffer gases. From the measured electron attachment rate constants, the electron attachment cross sections at 300, 400, and 500 K were determined using an unfolding technique. The maximum electron attachment cross sections at 300, 400, and 500 K were approximate to 3.1 x 10(-18), approximate to 8.2 x 10(-18), and approximate to 1.7 x 10(-17) cm(2), and occurred at electron energies of approximate to 0.8, approximate to 0.65, and approximate to 0.55 eV, respectively. The increase in electron attachment to methylene chloride with temperature is attributed to the increase in the vibrational energy of the molecule. (C) 1999 American Institute of Physics. [S0021-9606(99)00618-2]. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. RP Pinnaduwage, LA (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA. NR 27 TC 11 Z9 11 U1 1 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 8 PY 1999 VL 110 IS 18 BP 9011 EP 9016 DI 10.1063/1.478820 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 192HU UT WOS:000080073200019 ER PT J AU Corrales, LR AF Corrales, LR TI Dissociative model of water clusters SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MOLECULAR-DYNAMICS; AB-INITIO; SEMIEMPIRICAL METHODOLOGY; PROTON AFFINITIES; HYDROXIDE ION; LIQUID WATER; BOND; SIMULATION; ORBITALS; PRODUCTS AB A model of water is introduced that dissociates into either ionic or covalent molecular fragments. The model is based on a semiempirical calculation embedded in a molecular mechanics approach. It contains electronic degrees of freedom that allow the calculation of partial charges that vary smoothly from the bound state to the dissociated states. The hydrogen bond is modeled classically with Coulomb interactions, and shows significant improvement in predicting cluster behavior by adding directional character via an overlap between a lone pair orbital on oxygen and the hydrogen of an adjacent molecule. An implicit bond polarization is present due to stretching bonds and charge transfer when the hydrogen bonds are formed. The energetic and geometric properties of water dissociation products, molecular clusters, and ionic clusters are presented. (C) 1999 American Institute of Physics. [S0021-9606(99)51418-9]. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Corrales, LR (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. NR 42 TC 16 Z9 16 U1 0 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 8 PY 1999 VL 110 IS 18 BP 9071 EP 9080 DI 10.1063/1.478828 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 192HU UT WOS:000080073200027 ER PT J AU Pederson, LA Schatz, GC Ho, TS Hollebeek, T Rabitz, H Harding, LB Lendvay, G AF Pederson, LA Schatz, GC Ho, TS Hollebeek, T Rabitz, H Harding, LB Lendvay, G TI Potential energy surface and quasiclassical trajectory studies of the N(D-2)+H-2 reaction SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DISTRIBUTIONS; N(2(2)D); H2O; H-2 AB We present a global potential energy surface for the 1A " state of NH2 based on application of the reproducing kernel Hilbert space interpolation method to high quality ab initio (multireference configuration interaction! results. Extensive quasiclassical trajectory calculations are performed on this surface to study the N(D-2) + H-2/D-2 reaction dynamics. Comparison is made with calculations on the lower level [first order configuration interaction (FOCI)] surface of Kobayashi, Takayanagi, Yokoyama, Sato, and Tsunashima (KTYST). We find a saddle point energy of 2.3 (1.9) kcal/mol for the perpendicular approach for the second order configuration interaction (SOCI) (SOCI with Davidson correction) surfaces, and a collinear stationary point energy of 5.5 (4.6) kcal/mol. The ordering of these stationary points is reversed compared to the corresponding FOCI results, and the only true reaction path on our surface is perpendicular. The primary reaction mechanism is determined to be C-2v insertion to produce short lived (100-300 fs) NH2 intermediates. Angular distributions are found to be primarily forward-backward symmetric, with a slight bias towards backward scattering at low energies. Decay of the NH2's occurs before energy is fully randomized, so the product vibrational distributions are a little hotter than statistical-with vibrational population ratios NH(v "=1)/NH(v "=0)=0.8 and ND(v "=1)/ND(v "=0)=0.9 (near threshold). These ratios, and other aspects of the vibrational product distributions are in excellent agreement with recent laser induced fluorescence studies. (C) 1999 American Institute of Physics. [S0021-9606(99)02217-5]. C1 Northwestern Univ, Dept Chem, Evanston, IL 60208 USA. Princeton Univ, Dept Chem, Princeton, NJ 08544 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Hungarian Acad Sci, Inst Chem, H-1525 Budapest, Hungary. RP Pederson, LA (reprint author), Northwestern Univ, Dept Chem, 2145 Sheridan Rd, Evanston, IL 60208 USA. EM schatz@chem.nwu.edu RI Lendvay, Gyorgy/B-5397-2016 OI Lendvay, Gyorgy/0000-0002-2150-0376 NR 20 TC 109 Z9 109 U1 0 U2 4 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 8 PY 1999 VL 110 IS 18 BP 9091 EP 9100 DI 10.1063/1.478830 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 192HU UT WOS:000080073200029 ER PT J AU Marshall, SL AF Marshall, SL TI A rapidly convergent modified Green's function for Laplace's equation in a rectangular region SO PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES LA English DT Article DE Laplace's equation; modified Green's function; rectangular region ID NUMERICAL-METHODS; CHANNEL; FLOW; DISTRIBUTIONS; ELECTRODES; CYLINDER; PLANE AB A computationally useful expression for the modified Green's function in a rectangular region is derived. This can be used to obtain solutions of Laplace's equation or Poisson's equation for the electrical potential associated with any configuration of current sources that satisfies the condition of charge balance, and represents a generalization of a well-known result due to Newman applicable to an infinite channel. The starting point for the analysis is the very slowly converging Fourier-series expansion of the modified Green's function. This Fourier series can be separated into a Fourier series in one variable that can be summed in closed form, and a double Fourier series that can be partly summed with respect to one index and transformed by application of the Poisson summation formula and integration by residues. The result of applying the Poisson formula can be expressed either as a rapidly converging series of logarithmic functions, or as a rapidly converging Fourier series that can be integrated analytically with respect to the coordinates of the source point. The use of the modified Green's function is demonstrated first by determining potential distributions that arise from specification of uniform current density on two or more of the boundary surfaces. The potential in a cell with two electrodes embedded in opposite sides of the rectangle is then calculated, and circumstances in which this potential approaches the potential in an infinite channel are determined. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37381 USA. RP Marshall, SL (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37381 USA. RI Marshall, Simon/E-9518-2010 NR 39 TC 19 Z9 19 U1 0 U2 6 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 1364-5021 EI 1471-2946 J9 P ROY SOC A-MATH PHY JI Proc. R. Soc. A-Math. Phys. Eng. Sci. PD MAY 8 PY 1999 VL 455 IS 1985 BP 1739 EP 1766 DI 10.1098/rspa.1999.0378 PG 28 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 198AY UT WOS:000080400600006 ER PT J AU Brinker, CJ Lu, YF Sellinger, A Fan, HY AF Brinker, CJ Lu, YF Sellinger, A Fan, HY TI Evaporation-induced self-assembly: Nanostructures made easy SO ADVANCED MATERIALS LA English DT Article ID MESOPOROUS MOLECULAR-SIEVES; SILICA; FILMS; SURFACTANT; SPHERES; WATER; ROUTE AB Simple and efficient methods of organizing materials are key to the realization of a nanotech world. These authors report on recent developments in simple evaporation-induced self-assembly processes, which enable the rapid production of patterned porous or nanocomposite materials. The Figure shows a calcined particle exhibiting vesicular mesophase, which was generated by aerosol self-assembly of the tri-block copolymer P123. C1 Sandia Natl Labs, Direct Fabricat Dept 1831, Albuquerque, NM 87185 USA. Canon Res Ctr Amer Inc, Palo Alto, CA 94304 USA. Univ New Mexico, Ctr Microengineered Mat, Adv Mat Lab, Albuquerque, NM 87106 USA. RP Brinker, CJ (reprint author), Sandia Natl Labs, Direct Fabricat Dept 1831, POB 5800, Albuquerque, NM 87185 USA. RI Sellinger, Alan/C-6250-2015 OI Sellinger, Alan/0000-0001-6705-1548 NR 38 TC 1438 Z9 1458 U1 66 U2 669 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0935-9648 J9 ADV MATER JI Adv. Mater. PD MAY 7 PY 1999 VL 11 IS 7 BP 579 EP + DI 10.1002/(SICI)1521-4095(199905)11:7<579::AID-ADMA579>3.0.CO;2-R PG 8 WC Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 199UE UT WOS:000080501100019 ER PT J AU Fletcher, DE Wilkins, SD AF Fletcher, DE Wilkins, SD TI Glue secretion and adhesion by larvae of sailfin shiner (Pteronotropis hypselopterus) SO COPEIA LA English DT Article AB Pteronotropis hypselopterus (sailfin shiner) larvae attached to submerged objects with an elastic glue secreted from two pores located on their heads. The cement pores were located ventrally in hatchlings and migrated in an anterior and dorsal direction through a subterminal to a terminal position as larvae grew Larvae were adhesive and sedentary during the developmental interval from hatching until swim-up. Pteronotropis hypselopterus offspring were supplied solely by an endogenous energy source (yolk) throughout this entire developmental interval. During this interval, concurrently, yolk was depleted; the yolksac became more stream lined; and gill structures, mouth parts, lining of the gut, and posterior swimbladder all formed. Development of these features while larvae were adhesive and the subsequent inflation of the posterior swimbladder and movement into the water column were precursors to initial feeding and transition to a solely exogenous energy source. A brief period of overlap between endogenous and exogenous nourishment frequently occurred after swim-up. Adhesion and the sedentary behavior may help the young, poorly developed larvae to maintain their position in flowing water, while conserving endogenous energy stores for growth and development. Benefits may also include avoidance of predators and anoxic sediments. C1 Savannah River Ecol Lab, Aiken, SC 29802 USA. RP Fletcher, DE (reprint author), Savannah River Ecol Lab, Drawer E, Aiken, SC 29802 USA. NR 10 TC 2 Z9 2 U1 1 U2 1 PU AMER SOC ICHTHYOLOGISTS HERPETOLOGISTS PI CHARLESTON PA UNIV CHARLESTON, GRICE MARINE LABORATORY, 205 FORT JOHNSON RD, CHARLESTON, SC 29412 USA SN 0045-8511 J9 COPEIA JI Copeia PD MAY 7 PY 1999 IS 2 BP 274 EP 280 DI 10.2307/1447472 PG 7 WC Zoology SC Zoology GA 196DE UT WOS:000080293100003 ER PT J AU Fletcher, DE AF Fletcher, DE TI Male ontogeny and size-related variation in mass allocation of bluenose shiners (Pteronotropis welaka) SO COPEIA LA English DT Article ID GAMBUSIA-AFFINIS; SOCIAL-CONTROL; REPRODUCTION; POECILIIDAE; MATURATION; HOLBROOKI; STORAGE; GROWTH; CYCLE; RATES AB During the spawning season of Pteronotropis welaka (bluenose shiners), three types of males were present in the population that differed in size, coloration, morphology, and mass allotment. The smallest males (initial males) were less dimorphic in both coloration and morphology, whereas the largest males (terminal males) rep resented the peak in sexually dimorphic development. Intermediate-sized males (transitional males) were also intermediate in size and coloration. The three types of males represent phases of a continual ontogenetic sequence in which initial males were in the first phase of ontogeny of sexually mature males followed by transitional males that were in transition to the terminal phase, the climax of development. Transition into a terminal male involved the expansion of median fins and pelvic fins, formation of blue on the head, increase in iridescent patches on scales, loss of yellow pigment in the dorsal fin, and general intensification of black pigment. Variation in mass allocation among somatic, reproductive, and storage components occurred among phases of P. welaka males. Initial and terminal males allocated a similar relative amount of mass to testicular tissue. Transitional males, however, during the period of increased development of secondary sexual characters and growth allocated a lower proportion of their mass to reproduction. simultaneously, transitional males allocated the same relative mass to storage (fat deposits). Either transitional males allocated less mass to a functional testes, or delayed gonad maturation. Similar testes gross morphology observed among the types of males may indicate the former. This may represent a trade-off of current reproductive tissue development for somatic growth and development of secondary sexual characters, while not utilizing fat reserves that may be needed for future activities. C1 Savannah River Ecol Lab, Aiken, SC 29802 USA. RP Fletcher, DE (reprint author), Savannah River Ecol Lab, Drawer E, Aiken, SC 29802 USA. NR 26 TC 2 Z9 2 U1 1 U2 1 PU AMER SOC ICHTHYOLOGISTS HERPETOLOGISTS PI CHARLESTON PA UNIV CHARLESTON, GRICE MARINE LABORATORY, 205 FORT JOHNSON RD, CHARLESTON, SC 29412 USA SN 0045-8511 J9 COPEIA JI Copeia PD MAY 7 PY 1999 IS 2 BP 479 EP 486 DI 10.2307/1447495 PG 8 WC Zoology SC Zoology GA 196DE UT WOS:000080293100026 ER PT J AU Duncan, JB Nelson, DA AF Duncan, JB Nelson, DA TI The separation of tritiated water using supported polyphosphazene membranes SO JOURNAL OF MEMBRANE SCIENCE LA English DT Article DE inorganic membranes; composite membranes; ultrafiltration; polyphosphazene; tritiated water ID HEAVY-WATER; PERMEATION; LIGHT AB Carboxylated poly(diaryloxy)phosphazene was examined as the active constituent of the composite membranes to separate tritiated water (HTO) from light water. These membranes were tested with wafer containing 10 800 pCi/l and 3 mu Ci/l of tritiated water, respectively, under cross-flow filtration conditions. Reductions in the permeate of nearly 30% HTO were observed with these tritium concentrations. Low temperature (5 degrees C), low pressure (137.9-551.6 kPa), and high pH (near 10 or above) were required to obtain such reductions (rejection). Salt species (Na(2)SO(4), CaCl(2) and CaSO(4)) at various concentrations and pressures, within a 137.9-551.6 kPa range, did not appear to affect the HTO separation efficiency. Mass balances performed during these experiments indicate an unaccounted small amount of tritium (0.5-2.2%). Sorption experiments with the polyphosphazene suggest that the membrane does not operate by an ion exchange mechanism; that is, tritium accumulation within the membrane. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Pacific NW Lab, Richland, WA 99352 USA. RP Nelson, DA (reprint author), Pacific NW Lab, POB 999, Richland, WA 99352 USA. EM dave.nelson@pnl.gov NR 12 TC 3 Z9 3 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0376-7388 J9 J MEMBRANE SCI JI J. Membr. Sci. PD MAY 7 PY 1999 VL 157 IS 2 BP 211 EP 217 DI 10.1016/S0376-7388(98)00380-9 PG 7 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA 185BA UT WOS:000079647200007 ER PT J AU Segel, DJ Bachmann, A Hofrichter, J Hodgson, KO Doniach, S Kiefhaber, T AF Segel, DJ Bachmann, A Hofrichter, J Hodgson, KO Doniach, S Kiefhaber, T TI Characterization of transient intermediates in lysozyme folding with time-resolved small-angle X-ray scattering SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE SAXS; protein folding; folding intermediates; folding kinetics; lysozyme ID EGG-WHITE LYSOZYME; HEN LYSOZYME; ALPHA-LACTALBUMIN; KINETICS; STATES; DIFFRACTION; PROTEINS; PATHWAY AB We have used synchrotron radiation, together with stopped-flow and continuous-flow mixing techniques to monitor refolding of lysozyme at pH 5.2. From data measured at times which range from 14 ms to two seconds, we can monitor changes in the size, the shape and the pair distribution function of the polypeptide chain during the folding process. Comparison of the results with the properties of native and GdmCl-unfolded lysozyme shows that a major chain collapse occurs in the deadtime of mixing. During this process about 50 % of the change in radius of gyration between the unfolded protein and the native state occurs and the polypeptide chain adopts a globular shape. Time-resolved fluorescence spectra of this collapsed state suggest that the hydrophobic sidechains are still highly solvent accessible. A subsequently formed intermediate with helical structure in the cc-domain is nearly identical in size and shape with native lysozyme and has a solvent-inaccessible hydrophobic core. Despite its native-like properties, this intermediate is only slightly more stable (Delta G(0) = - 4 kJ/mol) than the collapsed state and still much less stable than native lysozyme (Delta Delta G(0) = 36 kJ/mol) at 20 degrees C. (C) 1999 Academic Press. C1 Stanford Univ, Dept Phys, Stanford, CA 94305 USA. Univ Basel, Dept Biophys Chem, Biozentrum, CH-4056 Basel, Switzerland. NIH, Chem Phys Lab, Bethesda, MD 20892 USA. Stanford Univ, Dept Chem, Stanford, CA 94305 USA. Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Doniach, S (reprint author), Stanford Univ, Dept Phys, Stanford, CA 94305 USA. RI Kiefhaber, Thomas/A-3028-2010 NR 30 TC 134 Z9 136 U1 3 U2 21 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-2836 J9 J MOL BIOL JI J. Mol. Biol. PD MAY 7 PY 1999 VL 288 IS 3 BP 489 EP 499 DI 10.1006/jmbi.1999.2703 PG 11 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 194QG UT WOS:000080204600014 PM 10329156 ER PT J AU Su, XC Kung, KY Lahtinen, J Shen, YR Somorjai, GA AF Su, XC Kung, KY Lahtinen, J Shen, YR Somorjai, GA TI 1,3- and 1,4-cyclohexadiene reaction intermediates in cyclohexene hydrogenation and dehydrogenation on Pt(111) crystal surface: a combined reaction kinetics and surface vibrational spectroscopy study using sum frequency generation SO JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL LA English DT Article DE hydrogenation; dehydrogenation; sum frequency generation ID ENERGY ELECTRON-DIFFRACTION; BISMUTH-COVERED PT(111); PLATINUM SURFACES; HREELS; CYCLOHEXADIENE; ADSORPTION; MOLECULES; BENZENE; SPECTRA; BPTDS AB The hydrogenation and dehydrogenation reactions of cyclohexene on Pt(lll) surface were investigated by surface vibrational spectroscopy via sum frequency generation (SFG) both under ultrahigh vacuum (UHV) and high pressure conditions with 10 Torr cyclohexene and various hydrogen pressures up to 590 Torr. Under UHV, cyclohexene on Pt(lll) undergoes a change from pi/sigma-bonded, sigma-bonded, and c-C6H9 surface species to adsorbed benzene when the surface was heated. A site-blocking effect was observed at saturation coverage of cyclohexene and caused the dehydrogenation to shift to higher surface temperature, At high pressures, however, none of the species observed in UHV condition were seen. 1,4-cyclohexadiene (CHD) was found to be the major species on the surface at 295 K even in the presence of nearly 600 Torr of hydrogen. Hydrogenation was the only detectable reaction at the temperature range between 300-400 K with I,3-CHD on the surface as revealed by SFG. Further increasing surface temperature results in a decrease in hydrogenation reaction rate and an increase in dehydrogenation reaction rate with both 1,3-CHD and 1,4-CHD detectable on the surface simultaneously. Monitoring the reaction kinetics and the chemical nature of surface species together allows us to postulate a reaction mechanism: cyclohexene hydrogenates to cyclohexane via a 1,3-CHD intermediate, and dehydrogenates to benzene through both 1,4-CHD and 1,3-CHD intermediates. Both 1,3- and 1,4-CHD dehydrogenate to benzene at sufficiently high temperature on Pt(111). (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Somorjai, GA (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. EM somorjai@cchem.berkeley.edu RI Lahtinen, Jouko/K-6804-2012 OI Lahtinen, Jouko/0000-0002-1192-9945 NR 28 TC 46 Z9 46 U1 0 U2 16 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1381-1169 J9 J MOL CATAL A-CHEM JI J. Mol. Catal. A-Chem. PD MAY 6 PY 1999 VL 141 IS 1-3 BP 9 EP 19 DI 10.1016/S1381-1169(98)00245-3 PG 11 WC Chemistry, Physical SC Chemistry GA 178VV UT WOS:000079290600004 ER PT J AU Dorsett, HE Watts, RO Xantheas, SS AF Dorsett, HE Watts, RO Xantheas, SS TI Probing temperature effects on the hydrogen bonding network of the Cl-(H2O)(2) cluster SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Letter ID AQUEOUS IONIC CLUSTERS; MANY-MODE SYSTEMS; WATER CLUSTERS; VIBRATIONAL SPECTROSCOPY; GAS-PHASE; MICROSCOPIC SOLVATION; SPECTRA; ENERGIES; MOLECULE; HYDRATION AB We have incorporated the flexible RWK2 water potential into the parametrization of a chloride-water interaction potential from first principles calculations and used it to investigate the temperature effects in the infrared (IR) spectrum of Cl-(H2O)(2). We have found that spectral signatures of hydrogen bonding between the two water molecules in the cluster disappear with increasing temperature, a consequence of the weak water-water interaction in the cluster. C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Univ Melbourne, Dept Chem, Parkville, Vic 3052, Australia. RP Xantheas, SS (reprint author), Pacific NW Lab, Environm Mol Sci Lab, POB 999,906 Battelle Blvd,MS K1-96, Richland, WA 99352 USA. RI Xantheas, Sotiris/L-1239-2015 NR 34 TC 57 Z9 57 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 6 PY 1999 VL 103 IS 18 BP 3351 EP 3355 DI 10.1021/jp984248a PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 196JA UT WOS:000080304200002 ER PT J AU Muntean, JV Nash, KL Rickert, PG Sullivan, JC AF Muntean, JV Nash, KL Rickert, PG Sullivan, JC TI Dynamic NMR study of ligand exchange reactions in U(VI)-phosphonic acid systems SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID CHLOROPHOSPHONAZO-III; STATISTICAL-MODEL; DISPERSION SPACE; DIPHOSPHONIC ACIDS; AQUEOUS-SOLUTIONS; COMPLEXATION; KINETICS; THERMODYNAMICS; PROBABILITY; EQUILIBRIA AB The rates of hydrogen ion exchange on phosphonic acid ligands and that of phosphonate ligand exchange on selected uranyl-phosphonate complexes have been investigated by dynamic NMR spectroscopy. The spin-spin relaxation time (In(1/T-2)) for H+ exchange on the free ligands exhibits a parabolic dependence on reciprocal temperature (1/T (K-1)). The empirical fit parameters are correlated with the activation parameters (Delta H*, Delta S*, Delta C-p*) by adapting the statistical mechanical framework developed by Braibanti ct al. to the Eyring activated complex theory. The correlation of the apparent activation enthalpy with temperature indicates that 6-11 water molecules participate in the transition from reactants to activated complex for ligand proton exchange reactions: depending on the ligand. Mechanistic details of ligand exchange reactions of phosphonic acid complexants onto the corresponding uranium(VI) complexes are not fully developed, but the negative values for Delta S* imply increased order in the transition to the activated complex. Though Delta H* for ligand exchange covers a range of 15 kJ/mol, the free energy of activation (Delta G*) is nearly constant for the series of ligands, implying substantial entropy compensation in the activation process. Application of the Marcus relationship defines a correlation between Delta G* and the thermodynamic stability (Delta G degrees) for the 1:2 uranyl complexes with methanediphosphonic acid and 1-hydroxyelhane-1,1-diphosphonic acid. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Nash, KL (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 17 TC 4 Z9 4 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 6 PY 1999 VL 103 IS 18 BP 3383 EP 3387 DI 10.1021/jp9848041 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 196JA UT WOS:000080304200007 ER PT J AU Wang, XB Ding, CF Nicholas, JB Dixon, DA Wang, LS AF Wang, XB Ding, CF Nicholas, JB Dixon, DA Wang, LS TI Investigation of free singly and doubly charged alkali metal sulfate ion pairs: M+(SO42-) and [M+(SO42-)](2) (M = Na, K) SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID WEAKLY COORDINATING ANIONS; GAS-PHASE; AB-INITIO; WATER; STABILIZATION; SPECTROSCOPY; STABILITY; SO4(2-) AB We present a combined experimental and theoretical investigation of alkali metal sulfate ion pairs and their doubly charged dimers in the gas phase: Na+SO42-, K+SO42-, (NaSO4)(2)(2-), (KSO4)(2)(2-), and NaK(SO4)(2)(2-). We produced these anions using an electrospray technique and measured their photoelectron spectra at three photon energies, 355, 266, and 193 nm. The photoelectron spectra of each anion exhibit two detachment features, which approximately correspond to detachment from the HOMO and HOMO-1 of the SO42- group perturbed by the cations. The electron binding energies of the dimer dianions are lower than those of the monomers because of the strong electron-electron repulsion in the dianions. We also observed the repulsive Coulomb barriers in the dianions and their effects on the photodetachment spectra. We used density functional theory and ab initio molecular orbital theory to obtain the geometric and electronic structure of the ion pairs. The calculated electron binding energies and orbital energy separations are in reasonable agreement with the experimental values. We found that the MSO4- ion pairs have C-3v symmetry with a C-2v structure slightly higher in energy. In the dimer dianions the two alkali metal cations bridge the two SO42- groups. C1 Washington State Univ, Dept Phys, Richland, WA 99352 USA. Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Nicholas, JB (reprint author), Washington State Univ, Dept Phys, Richland, WA 99352 USA. NR 38 TC 56 Z9 57 U1 0 U2 13 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 6 PY 1999 VL 103 IS 18 BP 3423 EP 3429 DI 10.1021/jp990071o PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 196JA UT WOS:000080304200012 ER PT J AU Czapski, G Lymar, SV Schwarz, HA AF Czapski, G Lymar, SV Schwarz, HA TI Acidity of the carbonate radical SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID AQUEOUS-SOLUTIONS; RADIOLYSIS; OH AB A pulse radiolysis study which uses a flow system to irradiate mixtures of H2CO3 and HCO3- within 50 ms of their formation has demonstrated that the carbonate radical is a strong acid, pK(a) < 0, contrary to published reports of high pK(a)s. The rate constant for reaction of the hydroxyl radical with H2CO3 is 7 x 10(4) M-1 s(-1) at about 5 degrees C. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Hebrew Univ Jerusalem, Dept Phys Chem, IL-91904 Jerusalem, Israel. RP Schwarz, HA (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. NR 15 TC 64 Z9 65 U1 5 U2 18 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 6 PY 1999 VL 103 IS 18 BP 3447 EP 3450 DI 10.1021/jp984769y PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 196JA UT WOS:000080304200016 ER PT J AU Sandrone, G Dixon, DA Hay, BP AF Sandrone, G Dixon, DA Hay, BP TI Conformational analysis of malonamide, N,N '-dimethylmalonamide, and N,N,N ',N '-tetramethylmalonamide SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID DENSITY FUNCTIONAL CALCULATIONS; NEUTRON-DIFFRACTION DATA; RETRO-INVERSO PEPTIDES; METAL-AMIDE COMPLEXES; H...O HYDROGEN-BONDS; VAN-DER-WAALS; FORCE-FIELD; BASIS-SETS; AB-INITIO; MOLECULAR CALCULATIONS AB This paper reports the results of a theoretical study to identify the stable conformers of malonamide, three geometric isomers of N,N'-dimethylmalonamide, and N,N,N'N'-tetramethylmalonamide at different levels of ab initio electronic structure theory. Two stable conformations are identified for each malonamide derivative examined. Only one of these 10 structures has previously been reported. The structural parameters and relative energies of these conformations are compared at the Hartree-Fock, local density functional theory, nonlocal density functional theory, and Moller-Plesset levels of theory. The results show that significant differences in both structure and energy are obtained at the different levels of theory. C1 Pacific NW Lab, Theory Modeling & Simulat Grp, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Pacific NW Lab, Theory Modeling & Simulat Grp, Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. NR 46 TC 28 Z9 28 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 6 PY 1999 VL 103 IS 18 BP 3554 EP 3561 DI 10.1021/jp990029t PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 196JA UT WOS:000080304200032 ER PT J AU Rajh, T Nedeljkovic, JM Chen, LX Poluektov, O Thurnauer, MC AF Rajh, T Nedeljkovic, JM Chen, LX Poluektov, O Thurnauer, MC TI Improving optical and charge separation properties of nanocrystalline TiO2 by surface modification with vitamin C SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Letter ID INTERFACIAL ELECTRON-TRANSFER; SEMICONDUCTOR PHOTOCATALYSIS; NANOPARTICLES; REDUCTION; DYNAMICS; COLLOIDS; IONS; XAFS; EPR AB The structural and electrochemical properties of nanoparticles were found to be different from those of the corresponding bulk semiconductors. Due to the specific binding of modifiers to "corner defects", the optical properties of small titania particles were red shifted 1.6 eV compared to unmodified nanocrystallites. It was found using electron paramagnetic resonance (EPR) that, as with organic charge transfer superconductors, these novel nanocrystallites operate with a charge-transfer mechanism, and exhibit semiconducting properties through both constituents (large band gap semiconductor and organic modifier). The EPR spectra were consistent with hole trapping on the surface modifier and electron trapping on shallow interstitial and partially delocalized Ti sites. These systems have an important feature in that charge pairs are instantaneously separated into two phases-the holes on the donating organic modifier and the electrons in the conduction band of TiO2. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Rajh, T (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 30 TC 249 Z9 251 U1 6 U2 57 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 6 PY 1999 VL 103 IS 18 BP 3515 EP 3519 DI 10.1021/jp9901904 PG 5 WC Chemistry, Physical SC Chemistry GA 196HW UT WOS:000080303800002 ER PT J AU Gomez, MA Pratt, LR Hummer, G Garde, S AF Gomez, MA Pratt, LR Hummer, G Garde, S TI Molecular realism in default models for information theories of hydrophobic effects SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Letter ID LIQUIDS; DENATURATION; HYDRATION; CAVITIES; SOLUTES; WATER AB This tercer considers several physical arguments about contributions to hydrophobic hydration of inert gases, constructs default models to test them within information theories, and gives information theory predictions using those default models with moment information drawn from simulation of liquid water. Tested physical features include packing or steric effects, the role of attractive forces that lower the solvent pressure, and the roughly tetrahedral coordination of water molecules in liquid water. Packing effects (hard-sphere default model) and packing effects plus attractive forces (Lennard-Jones default model) are ineffective in improving the prediction of hydrophobic hydration free energies of inert gases over the previously used fiat default model. However, a conceptually simple cluster Poisson model that incorporates tetrahedral coordination structure in the default model is effective for these predictions. These results provide a partial rationalization of the remarkable performance of the flat default model with two moments in previous applications. The cluster Poisson default model thus will be the subject of further refinement. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Gomez, MA (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RI Garde, Shekhar/C-3060-2008; Pratt, Lawrence/H-7955-2012; Hummer, Gerhard/A-2546-2013 OI Pratt, Lawrence/0000-0003-2351-7451; Hummer, Gerhard/0000-0001-7768-746X NR 21 TC 36 Z9 36 U1 1 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 6 PY 1999 VL 103 IS 18 BP 3520 EP 3523 DI 10.1021/jp990337r PG 4 WC Chemistry, Physical SC Chemistry GA 196HW UT WOS:000080303800003 ER PT J AU Cho, H Hong, J Maeda, T Donovan, SM Abernathy, CR Pearton, SJ Shul, RJ AF Cho, H Hong, J Maeda, T Donovan, SM Abernathy, CR Pearton, SJ Shul, RJ TI Novel plasma chemistries for highly selective dry etching of InxGaN1-x: BI3 and BBr3 SO MATERIALS SCIENCE AND ENGINEERING B-SOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY LA English DT Article DE novel plasma chemistries; dry etching; low damage condition ID OHMIC CONTACTS; NITRIDE; INP; CL2 AB There is increasing need for dry etching chemistries with high selectivity for one nitride over another. In high power nitride-based electronic devices, selective removal of InN or InGaN contact layers in HEMTs or HFETs, or base layers in HBTs under low damage condition is necessary. Two new plasma chemistries, BI3 and BBr3 are found to produce maximum etch selectivities of ca. 100 for InN over GaN and AlN in ICP discharges, due to the relatively high volatility of InI3 and InBr3 etch products. Surface morphology of the etched nitrides is found to depend on plasma composition, chuck power and source power, but root-mean-square roughness similar to the as-grown materials are obtained over a wide range of etching conditions. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Cho, H (reprint author), Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. NR 15 TC 3 Z9 4 U1 1 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5107 J9 MAT SCI ENG B-SOLID JI Mater. Sci. Eng. B-Solid State Mater. Adv. Technol. PD MAY 6 PY 1999 VL 59 IS 1-3 BP 340 EP 344 DI 10.1016/S0921-5107(98)00379-1 PG 5 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 203CB UT WOS:000080689000071 ER PT J AU Cao, XA Pearton, SJ Donovan, SM Abernathy, CR Ren, F Zolper, JC Cole, MW Zeitouny, A Eizenberg, M Shul, RJ Baca, AG AF Cao, XA Pearton, SJ Donovan, SM Abernathy, CR Ren, F Zolper, JC Cole, MW Zeitouny, A Eizenberg, M Shul, RJ Baca, AG TI Thermal stability of WSix and W ohmic contacts on GaN SO MATERIALS SCIENCE AND ENGINEERING B-SOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY LA English DT Article DE thermal stability; ohmic contacts; metallization AB We have sputter-deposited 500-1200 Angstrom thick WSi0.45 and W metallization onto both n(+) GaN (n = 10(19) cm(-3)) doped either during MOCVD growth or by direct Si+ ion implantation (5 x 10(15) cm(-2), 100 keV) activated by RTA at 1400 degrees C for 10 s and p(+) (N-A = 10(18) cm(-3)) GaN. In the n-type epi samples R-c values of 10(-4) Ohm cm(-2) were obtained and were stable to similar to 1000 degrees C. The annealing treatments up to 600 degrees C had little effect on the WSix/GaN interface, but the beta-W2N phase formed between 700-800 degrees C, concomitant with a strong reduction (approximately a factor of 2) in near-surface crystalline defects in the GaN. Spiking of the metallization down the threading and misfit dislocations was observed at 800 degrees C, extending > 5000 Angstrom in some cases. This can create junction shorting in bipolar or thyristor devices. R-c values of similar to 10(-6) Ohm cm(-2) were obtained on the implanted samples for 950 degrees C annealing, with values of similar to 10(-5) Ohm cm(-2) after 1050 degrees C anneals. On p-GaN, the contacts are essentially leaky Schottky diodes at 25 degrees C. but became ohmic at greater than or equal to 250 degrees C, with R-c in the 10(-3) Ohm cm(-2) range. The W-based metallization is much more thermally stable than the more common Ni/Au. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. Off Naval Res, Arlington, VA 22217 USA. USA, Res Lab, WMRD, Aberdeen Proving Ground, MD 21105 USA. Technion Israel Inst Technol, Dept Mat Engn, IL-32000 Haifa, Israel. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Pearton, SJ (reprint author), Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. NR 10 TC 3 Z9 3 U1 0 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5107 J9 MAT SCI ENG B-SOLID JI Mater. Sci. Eng. B-Solid State Mater. Adv. Technol. PD MAY 6 PY 1999 VL 59 IS 1-3 BP 362 EP 365 DI 10.1016/S0921-5107(98)00351-1 PG 4 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 203CB UT WOS:000080689000076 ER PT J AU Smith, AG Simpson, GS Billowes, J Durell, JL Dagnall, PJ Freeman, SJ Leddy, M Roach, AA Smith, JF Jungclaus, A Lieb, KP Teich, C Gall, BJP Hoellinger, F Schulz, N Ahmad, I Greene, J Algora, A AF Smith, AG Simpson, GS Billowes, J Durell, JL Dagnall, PJ Freeman, SJ Leddy, M Roach, AA Smith, JF Jungclaus, A Lieb, KP Teich, C Gall, BJP Hoellinger, F Schulz, N Ahmad, I Greene, J Algora, A TI Measurements of g-factors of excited states in Ba and Ce nuclei using gamma rays from secondary fission fragments SO PHYSICS LETTERS B LA English DT Article ID MAGNETIC-MOMENTS; 2(1)+ STATES; ISOTOPES AB Measurements of g-factors of excited states in barium and cerium fission fragments have been performed using time-integral perturbed angular correlations between secondary-fragment gamma rays. Larmor precession angles have been obtained for the first I-pi = 2(+) states in Ba-144,Ba-146 and Ce-146,Ce-148 as well as for the 9/2(-) state at 117 keV in Ba-143, the 7/2(-) state at 114 keV in Ba-145 and the first 4(+) state in Ce-150. The deduced g-factor fur the 2(+) state in Ba-146 provides substantiating evidence for a downward trend in 2(+) g-factors with increasing neutron number, in line with Interacting Boson Model predictions for the neutron-rich barium isotopes, assuming the quenching of the Z = 64 shell gap for N>88. The static hyperfine fields for implanted barium and cerium isotopes are found to be opposite in sign. These results constitute the first use of secondary-fragment gamma-ray emission in the determination of g-factors of excited states in fission fragments. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Manchester, Dept Phys & Astron, Manchester M13 9PL, Lancs, England. Univ Gottingen, Inst Phys 2, D-37073 Gottingen, Germany. Univ Strasbourg 1, CNRS, IN2P3, Inst Rech Subatom, F-67037 Strasbourg, France. Argonne Natl Lab, Argonne, IL 60439 USA. Lab Nazl Legnaro, I-35020 Legnaro, PD, Italy. RP Smith, AG (reprint author), Univ Manchester, Dept Phys & Astron, Manchester M13 9PL, Lancs, England. RI Freeman, Sean/B-1280-2010; Algora, Alejandro/E-2960-2015 OI Freeman, Sean/0000-0001-9773-4921; Algora, Alejandro/0000-0002-5199-1794 NR 16 TC 18 Z9 18 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD MAY 6 PY 1999 VL 453 IS 3-4 BP 206 EP 210 DI 10.1016/S0370-2693(99)00332-9 PG 5 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 200UD UT WOS:000080557700004 ER PT J AU Aclander, J Alster, J Barton, D Bunce, G Carroll, A Christensen, N Courant, H Durrant , S Gushue, S Heppelmann, S Kosonovsky, E Mardor, I Mardor, Y Marshak, M Makdisi, Y Minor, ED Navon, I Nicholson, H Piasetzky, E Roser, T Russell, J Sargsian, M Sutton, CS Tanaka, M White, C Wu, JY AF Aclander, J Alster, J Barton, D Bunce, G Carroll, A Christensen, N Courant, H Durrant , S Gushue, S Heppelmann, S Kosonovsky, E Mardor, I Mardor, Y Marshak, M Makdisi, Y Minor, ED Navon, I Nicholson, H Piasetzky, E Roser, T Russell, J Sargsian, M Sutton, CS Tanaka, M White, C Wu, JY TI The large momentum transfer reaction C-12(p,2 p plus n) as a new method for measuring short range NN correlations in nuclei SO PHYSICS LETTERS B LA English DT Article ID ELECTRON-SCATTERING; PROTON POLARIZATION; RESONANCE REGION; PI+ ABSORPTION; LIGHT-NUCLEI; DEPENDENCE AB The reaction C-12(p,2p + n) was measured for momentum transfers of 4.8 and 6.2 (GeV/c)(2) at beam momenta of 5.9 and 7.5 GeV/c. We measured the quasi-elastic reaction (p,2p) at theta(cm) similar or equal to 900, in a kinematically complete measurement. The neutron momentum was measured in triple coincidence with the two emerging high momentum protons. We present the correlation between the momenta of the struck target proton and the neutron. The events are associated with the high momentum components of the nuclear wave function. We present sparse data which, combined with a quasi elastic description of the (p,2p) reaction and kinematical arguments, point to a novel way for isolating two-nucleon short range correlations. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Tel Aviv Univ, Sackler Fac Exact Sci, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Minnesota, Dept Phys, Minneapolis, MN 55455 USA. Penn State Univ, Dept Phys, University Pk, PA 16802 USA. Mt Holyoke Coll, S Hadley, MA 01075 USA. Univ Massachusetts, Dept Phys, Dartmouth, MA USA. RP Aclander, J (reprint author), Tel Aviv Univ, Sackler Fac Exact Sci, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. RI Marshak, Marvin/B-8645-2008 NR 40 TC 23 Z9 23 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 EI 1873-2445 J9 PHYS LETT B JI Phys. Lett. B PD MAY 6 PY 1999 VL 453 IS 3-4 BP 211 EP 216 DI 10.1016/S0370-2693(99)00336-6 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 200UD UT WOS:000080557700005 ER PT J AU Acciarri, M Achard, P Adriani, O Aguilar-Benitez, M Alcaraz, J Alemanni, G Allaby, J Aloisio, A Alviggi, MG Ambrosi, G Anderhub, H Andreev, VP Angelescu, T Anselmo, F Arefiev, A Azemoon, T Aziz, T Bagnaia, P Baksay, L Balandras, A Ball, RC Banerjee, S Banerjee, S Banicz, K Barczyk, A Barillere, R Barone, L Bartalini, P Basile, M Battiston, R Bay, A Becattini, F Becker, U Behner, F Berdugo, J Berges, P Bertucci, B Betev, BL Bhattacharya, S Biasini, M Biland, A Blaising, JJ Blyth, SC Bobbink, GJ Bohm, A Boldizsar, L Borgia, B Bourilkov, D Bourquin, M Braccini, S Branson, JG Brigljevic, V Brochu, F Buffini, A Buijs, A Burger, JD Burger, WJ Busenitz, J Button, A Cai, XD Campanelli, M Capell, M Romeo, GC Carlino, G Cartacci, AM Casaus, J Castellini, G Cavallari, F Cavallo, N Cecchi, C Cerrada, M Cesaroni, F Chamizo, M Chang, YH Chaturvedi, UK Chemarin, M Chen, A Chen, G Chen, GM Chen, HF Chen, HS Chereau, X Chiefari, G Cifarelli, L Cindolo, F Civinini, C Clare, I Clare, R Coignet, G Colijn, AP Colino, N Costantini, S Cotorobai, F de la Cruz, B Csilling, A Dai, TS van Dalen, JA D'Alessandro, R de Asmundis, R Deglon, P Degre, A Deiters, K della Volpe, D Denes, P DeNotaristefani, F De Salvo, A Diemoz, M van Dierendonck, D Di Lodovico, F Dionisi, C Dittmar, M Dominguez, A Doria, A Dova, MT Duchesneau, D Dufournand, D Duinker, P Duran, I El Mamouni, H Engler, A Eppling, FJ Erne, FC Extermann, P Fabre, M Faccini, R Falagan, MA Falciano, S Favara, A Fay, J Fedin, O Felcini, M Ferguson, T Ferroni, F Fesefeldt, F Fiandrini, E Field, JH Filthaut, F Fisher, PH Fisk, I Ferconi, G Fredj, L Freudenreich, K Furetta, C Galaktionov, Y Ganguli, SN Garcia-Abia, P Gataullin, M Gau, SS Gentile, S Gheordanescu, N Giagu, S Goldfarb, S Gong, ZF Gruenewald, MW van Gulik, R Gupta, VK Gurtu, A Gutay, LJ Haas, D Hasan, A Hatzifotiadou, D Hebbeker, T Herve, A Hidas, P Hirschfelder, J Hofer, H Holzner, G Hoorani, H Hou, SR Iashvili, I Jin, BN Jones, LW de Jong, P Josa-Mutuberria, I Khan, RA Kamrad, D Kapustinsky, JS Kaur, M Kienzle-Focacci, MN Kim, D Kim, DH Kim, JK Kim, SC Kinnison, WW Kirkby, J Kiss, D Kittel, W Klimentov, A Konig, AC Kopp, A Korolko, I Koutsenko, V Kraemer, RW Krenz, W Kunin, A Lacentre, P de Guevara, PL Laktineh, I Landi, G Lapoint, C Lassila-Perini, K Laurikainen, P Lavorato, A Lebeau, M Lebedev, A Lebrun, P Lecomte, P Lecoq, P Le Coultre, P Lee, HJ Le Goff, JM Leiste, R Leonardi, E Levtchenko, P Li, C Lin, CH Lin, WT Linde, FL Lista, L Liu, ZA Lohmann, W Longo, E Lu, YS Lubelsmeyer, K Luci, C Luckey, D Luminari, L Lustermann, W Ma, WG Maity, M Majumder, G Malgeri, L Malinin, A Mana, C Mangeol, D Marchesini, P Marian, G Martin, JP Marzano, F Massaro, GGG Mazumdar, K McNeil, RR Mele, S Merola, L Meschini, M Metzger, WJ von der Mey, M Migani, D Mihul, A Milcent, H Mirabelli, G Mnich, J Molnar, P Monteleoni, B Moulik, T Muanza, GS Muheim, F Muijs, AJM Nahn, S Napolitano, M Nessi-Tedaldi, F Newman, H Niessen, T Nippe, A Nisati, A Nowak, H Oh, YD Organtini, G Ostonen, R Palomares, C Pandoulas, D Paoletti, S Paolucci, P Park, HK Park, IH Pascale, G Passaleva, G Patricelli, S Paul, T Pauluzzi, M Paus, C Pauss, F Peach, D Pedace, M Pei, YJ Pensotti, S Perret-Gallix, D Petersen, B Petrak, S Piccolo, D Pieri, M Piroue, PA Pistolesi, E Plyaskin, V Pohl, M Pojidaev, V Postema, H Pothier, J Produit, N Prokofiev, D Quartieri, J Rahal-Callot, G Raja, N Rancoita, PG Raven, G Razis, P Ren, D Rescigno, M Reucroft, S van Rhee, T Riemann, S Riles, K Robohm, A Rodin, J Roe, BP Romero, L Rosier-Lees, S Rubio, JA Ruschmeier, D Rykaczewski, H Sakar, S Salicio, J Sanchez, E Sanders, MP Sarakinos, ME Schafer, C Schegelsky, V Schmidt-Kaerst, S Schmitz, D Scholz, N Schopper, H Schotanus, DJ Schwenke, J Schwering, G Sciacca, C Sciarrino, D Servoli, L Shevchenko, S Shivarov, N Shoutko, V Shukla, J Shumilov, E Shvorob, A Siedenburg, T Son, D Smith, B Spillantini, P Steuer, M Stickland, DP Stone, A Stone, H Stoyanov, B Straessner, A Sudhakar, K Sultanov, G Sun, LZ Suter, H Swain, JD Szillasi, Z Tang, XW Tauscher, L Taylor, L Timmermans, C Ting, SCC Ting, SM Tonwar, SC Toth, J Tully, C Tung, KL Uchida, Y Ulbricht, J Valente, E Vesztergombi, G Vetlitsky, I Viertel, G Villa, S Vivargent, M Vlachos, S Vogel, H Vogt, H Vorobiev, I Vorobyov, AA Vorvolakos, A Wadhwa, M Wallraff, W Wang, JC Wang, XL Wang, ZM Weber, A Weber, M Wienemann, P Wilkens, H Wu, SX Wynhoff, S Xia, L Xu, ZZ Yang, BZ Yang, CG Yang, HJ Yang, M Ye, JB Yeh, SC You, JM Zalite, A Zalite, Y Zemp, P Zhang, ZP Zhu, GY Zhu, RY Zichichi, A Ziegler, F Zilizi, G Zoller, M AF Acciarri, M Achard, P Adriani, O Aguilar-Benitez, M Alcaraz, J Alemanni, G Allaby, J Aloisio, A Alviggi, MG Ambrosi, G Anderhub, H Andreev, VP Angelescu, T Anselmo, F Arefiev, A Azemoon, T Aziz, T Bagnaia, P Baksay, L Balandras, A Ball, RC Banerjee, S Banerjee, S Banicz, K Barczyk, A Barillere, R Barone, L Bartalini, P Basile, M Battiston, R Bay, A Becattini, F Becker, U Behner, F Berdugo, J Berges, P Bertucci, B Betev, BL Bhattacharya, S Biasini, M Biland, A Blaising, JJ Blyth, SC Bobbink, GJ Bohm, A Boldizsar, L Borgia, B Bourilkov, D Bourquin, M Braccini, S Branson, JG Brigljevic, V Brochu, F Buffini, A Buijs, A Burger, JD Burger, WJ Busenitz, J Button, A Cai, XD Campanelli, M Capell, M Romeo, GC Carlino, G Cartacci, AM Casaus, J Castellini, G Cavallari, F Cavallo, N Cecchi, C Cerrada, M Cesaroni, F Chamizo, M Chang, YH Chaturvedi, UK Chemarin, M Chen, A Chen, G Chen, GM Chen, HF Chen, HS Chereau, X Chiefari, G Cifarelli, L Cindolo, F Civinini, C Clare, I Clare, R Coignet, G Colijn, AP Colino, N Costantini, S Cotorobai, F de la Cruz, B Csilling, A Dai, TS van Dalen, JA D'Alessandro, R de Asmundis, R Deglon, P Degre, A Deiters, K della Volpe, D Denes, P DeNotaristefani, F De Salvo, A Diemoz, M van Dierendonck, D Di Lodovico, F Dionisi, C Dittmar, M Dominguez, A Doria, A Dova, MT Duchesneau, D Dufournand, D Duinker, P Duran, I El Mamouni, H Engler, A Eppling, FJ Erne, FC Extermann, P Fabre, M Faccini, R Falagan, MA Falciano, S Favara, A Fay, J Fedin, O Felcini, M Ferguson, T Ferroni, F Fesefeldt, F Fiandrini, E Field, JH Filthaut, F Fisher, PH Fisk, I Ferconi, G Fredj, L Freudenreich, K Furetta, C Galaktionov, Y Ganguli, SN Garcia-Abia, P Gataullin, M Gau, SS Gentile, S Gheordanescu, N Giagu, S Goldfarb, S Gong, ZF Gruenewald, MW van Gulik, R Gupta, VK Gurtu, A Gutay, LJ Haas, D Hasan, A Hatzifotiadou, D Hebbeker, T Herve, A Hidas, P Hirschfelder, J Hofer, H Holzner, G Hoorani, H Hou, SR Iashvili, I Jin, BN Jones, LW de Jong, P Josa-Mutuberria, I Khan, RA Kamrad, D Kapustinsky, JS Kaur, M Kienzle-Focacci, MN Kim, D Kim, DH Kim, JK Kim, SC Kinnison, WW Kirkby, J Kiss, D Kittel, W Klimentov, A Konig, AC Kopp, A Korolko, I Koutsenko, V Kraemer, RW Krenz, W Kunin, A Lacentre, P de Guevara, PL Laktineh, I Landi, G Lapoint, C Lassila-Perini, K Laurikainen, P Lavorato, A Lebeau, M Lebedev, A Lebrun, P Lecomte, P Lecoq, P Le Coultre, P Lee, HJ Le Goff, JM Leiste, R Leonardi, E Levtchenko, P Li, C Lin, CH Lin, WT Linde, FL Lista, L Liu, ZA Lohmann, W Longo, E Lu, YS Lubelsmeyer, K Luci, C Luckey, D Luminari, L Lustermann, W Ma, WG Maity, M Majumder, G Malgeri, L Malinin, A Mana, C Mangeol, D Marchesini, P Marian, G Martin, JP Marzano, F Massaro, GGG Mazumdar, K McNeil, RR Mele, S Merola, L Meschini, M Metzger, WJ von der Mey, M Migani, D Mihul, A Milcent, H Mirabelli, G Mnich, J Molnar, P Monteleoni, B Moulik, T Muanza, GS Muheim, F Muijs, AJM Nahn, S Napolitano, M Nessi-Tedaldi, F Newman, H Niessen, T Nippe, A Nisati, A Nowak, H Oh, YD Organtini, G Ostonen, R Palomares, C Pandoulas, D Paoletti, S Paolucci, P Park, HK Park, IH Pascale, G Passaleva, G Patricelli, S Paul, T Pauluzzi, M Paus, C Pauss, F Peach, D Pedace, M Pei, YJ Pensotti, S Perret-Gallix, D Petersen, B Petrak, S Piccolo, D Pieri, M Piroue, PA Pistolesi, E Plyaskin, V Pohl, M Pojidaev, V Postema, H Pothier, J Produit, N Prokofiev, D Quartieri, J Rahal-Callot, G Raja, N Rancoita, PG Raven, G Razis, P Ren, D Rescigno, M Reucroft, S van Rhee, T Riemann, S Riles, K Robohm, A Rodin, J Roe, BP Romero, L Rosier-Lees, S Rubio, JA Ruschmeier, D Rykaczewski, H Sakar, S Salicio, J Sanchez, E Sanders, MP Sarakinos, ME Schafer, C Schegelsky, V Schmidt-Kaerst, S Schmitz, D Scholz, N Schopper, H Schotanus, DJ Schwenke, J Schwering, G Sciacca, C Sciarrino, D Servoli, L Shevchenko, S Shivarov, N Shoutko, V Shukla, J Shumilov, E Shvorob, A Siedenburg, T Son, D Smith, B Spillantini, P Steuer, M Stickland, DP Stone, A Stone, H Stoyanov, B Straessner, A Sudhakar, K Sultanov, G Sun, LZ Suter, H Swain, JD Szillasi, Z Tang, XW Tauscher, L Taylor, L Timmermans, C Ting, SCC Ting, SM Tonwar, SC Toth, J Tully, C Tung, KL Uchida, Y Ulbricht, J Valente, E Vesztergombi, G Vetlitsky, I Viertel, G Villa, S Vivargent, M Vlachos, S Vogel, H Vogt, H Vorobiev, I Vorobyov, AA Vorvolakos, A Wadhwa, M Wallraff, W Wang, JC Wang, XL Wang, ZM Weber, A Weber, M Wienemann, P Wilkens, H Wu, SX Wynhoff, S Xia, L Xu, ZZ Yang, BZ Yang, CG Yang, HJ Yang, M Ye, JB Yeh, SC You, JM Zalite, A Zalite, Y Zemp, P Zhang, ZP Zhu, GY Zhu, RY Zichichi, A Ziegler, F Zilizi, G Zoller, M CA L3 Collaboration TI Measurement of the cross-section for the process gamma*gamma* -> hadrons at LEP SO PHYSICS LETTERS B LA English DT Article ID PHOTON-PHOTON INTERACTIONS; W-PAIR PRODUCTION; HIGH-ENERGIES; MONTE-CARLO; L3 EXPERIMENT; DETECTOR; COLLISIONS; SCATTERING; LEP2/NLC; POMERON AB Measurements of the two-photon interaction e(+)e(-) --> e(+)e(-) + hadrons at root s similar or equal to 91 GeV and root s similar or equal to 183 GeV are presented. The double-tag events, collected with the L3 detector, correspond to integrated luminosities of 140 pb(-1) at 91 GeV and 52 ph(-1) at 183 GeV. The cross-section of gamma*gamma* collisions has been measured at [Q(2)] = 3.5 GeV2 and [Q(2)] = 14 GeV2. The data agree well with predictions based on perturbative QCD, while the Quark Parton Model alone is insufficient to describe the data. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Ist Nazl Fis Nucl, Sez Milano, I-20133 Milan, Italy. Rhein Westfal TH Aachen, Inst Phys 1, D-52056 Aachen, Germany. Rhein Westfal TH Aachen, Inst Phys 3, D-52056 Aachen, Germany. NIKHEF H, Natl Inst High Energy Phys, NL-1009 DB Amsterdam, Netherlands. Univ Amsterdam, NL-1009 DB Amsterdam, Netherlands. Univ Michigan, Ann Arbor, MI 48109 USA. CNRS, IN2P3, LAPP, Lab Annecy Le Vieux Phys Particules, F-74941 Annecy Le Vieux, France. Univ Basel, Inst Phys, CH-4056 Basel, Switzerland. Louisiana State Univ, Baton Rouge, LA 70803 USA. Inst High Energy Phys, Beijing 100039, Peoples R China. Humboldt Univ, D-10099 Berlin, Germany. Univ Bologna, I-40126 Bologna, Italy. Ist Nazl Fis Nucl, Sez Bologna, I-40126 Bologna, Italy. Tata Inst Fundamental Res, Bombay 400005, Maharashtra, India. Northeastern Univ, Boston, MA 02115 USA. Inst Atom Phys, R-76900 Bucharest, Romania. Univ Bucharest, R-76900 Bucharest, Romania. Hungarian Acad Sci, Cent Res Inst Phys, H-1525 Budapest 114, Hungary. MIT, Cambridge, MA 02139 USA. Ist Nazl Fis Nucl, Sez Firenze, I-50125 Florence, Italy. Univ Florence, I-50125 Florence, Italy. World Lab, FBLJA Project, CH-1211 Geneva 23, Switzerland. CERN, European Lab Particle Phys, CH-1211 Geneva 23, Switzerland. Univ Geneva, CH-1211 Geneva 4, Switzerland. Univ Sci & Technol China, Hefei 230029, Anhui, Peoples R China. Res Inst High Energy Phys, SEFT, SF-00014 Helsinki, Finland. Univ Lausanne, CH-1015 Lausanne, Switzerland. Ist Nazl Fis Nucl, Sez Lecce, I-73100 Lecce, Italy. Univ Lecce, I-73100 Lecce, Italy. Los Alamos Natl Lab, Los Alamos, NM 87544 USA. Univ Lyon 1, CNRS, IN2P3, Inst Phys Nucl Lyon, F-69622 Villeurbanne, France. CIEMAT, E-28040 Madrid, Spain. ITEP, Moscow, Russia. Ist Nazl Fis Nucl, Sez Napoli, I-80125 Naples, Italy. Univ Naples Federico II, I-80125 Naples, Italy. Univ Cyprus, Dept Nat Sci, Nicosia, Cyprus. Catholic Univ Nijmegen, NL-6525 ED Nijmegen, Netherlands. Natl Inst Nucl Phys & High Energy Phys, NL-6525 ED Nijmegen, Netherlands. CALTECH, Pasadena, CA 91125 USA. Ist Nazl Fis Nucl, Sez Perugia, I-06100 Perugia, Italy. Univ Perugia, I-06100 Perugia, Italy. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Princeton Univ, Princeton, NJ 08544 USA. Ist Nazl Fis Nucl, Sez Roma, I-00185 Rome, Italy. Univ Roma La Sapienza, I-00185 Rome, Italy. Russian Acad Sci, Inst Nucl Phys, St Petersburg, Russia. Univ Salerno, I-84100 Salerno, Italy. Ist Nazl Fis Nucl, I-84100 Salerno, Italy. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Santiago, Dept Fis Particulas Elementales, E-15706 Santiago, Spain. Bulgarian Acad Sci, Cent Lab Mechatron & Instrumentat, BU-1113 Sofia, Bulgaria. Korea Adv Inst Sci & Technol, Ctr High Energy Phys, Taejon 305701, South Korea. Univ Alabama, University, AL 35486 USA. Univ Utrecht, NL-3584 CB Utrecht, Netherlands. NIKHEF H, NL-3584 CB Utrecht, Netherlands. Purdue Univ, W Lafayette, IN 47907 USA. Paul Scherrer Inst, CH-5232 Villigen, Switzerland. DESY, Inst Hochenergiephys, D-15738 Zeuthen, Germany. Swiss Fed Inst Technol, CH-8093 Zurich, Switzerland. Univ Hamburg, D-22761 Hamburg, Germany. Natl Cent Univ, Chungli 32054, Taiwan. Natl Tsing Hua Univ, Dept Phys, Hsinchu, Taiwan. RP Acciarri, M (reprint author), Ist Nazl Fis Nucl, Sez Milano, Via Celoria 16, I-20133 Milan, Italy. RI Achard, Pablo/C-2983-2009; Sanchez, Eusebio/H-5228-2015; Duran, Ignacio/H-7254-2015; Rancoita, Pier Giorgio/J-9896-2015; Hoorani, Hafeez/D-1791-2013; Palomares, Carmen/H-7783-2015; Fedin, Oleg/H-6753-2016; Di Lodovico, Francesca/L-9109-2016; Yang, Haijun/O-1055-2015; bertucci, bruna/J-5237-2012; Cavallo, Nicola/F-8913-2012; Cerrada, Marcos/J-6934-2014; de la Cruz, Begona/K-7552-2014; Josa, Isabel/K-5184-2014; Vogel, Helmut/N-8882-2014; Ferguson, Thomas/O-3444-2014; Berdugo, Javier/A-2858-2015; D'Alessandro, Raffaello/F-5897-2015; Fiandrini, Emanuele/C-4549-2008; Lista, Luca/C-5719-2008; Kirkby, Jasper/A-4973-2012; Servoli, Leonello/E-6766-2012; OI Achard, Pablo/0000-0002-4865-3196; Sanchez, Eusebio/0000-0002-9646-8198; Rancoita, Pier Giorgio/0000-0002-1990-4283; Palomares, Carmen/0000-0003-4374-9065; Di Lodovico, Francesca/0000-0003-3952-2175; Ambrosi, Giovanni/0000-0001-6977-9559; Longo, Egidio/0000-0001-6238-6787; Cerrada, Marcos/0000-0003-0112-1691; Vogel, Helmut/0000-0002-6109-3023; Ferguson, Thomas/0000-0001-5822-3731; Berdugo, Javier/0000-0002-7911-8532; D'Alessandro, Raffaello/0000-0001-7997-0306; Kirkby, Jasper/0000-0003-2341-9069; Servoli, Leonello/0000-0003-1725-9185; Castellini, Guido/0000-0002-0177-0643; Diemoz, Marcella/0000-0002-3810-8530; Doria, Alessandra/0000-0002-5381-2649; Faccini, Riccardo/0000-0003-2613-5141 NR 36 TC 54 Z9 54 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 EI 1873-2445 J9 PHYS LETT B JI Phys. Lett. B PD MAY 6 PY 1999 VL 453 IS 3-4 BP 333 EP 342 DI 10.1016/S0370-2693(99)00278-6 PG 10 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 200UD UT WOS:000080557700023 ER PT J AU Arko, AJ Joyce, JJ Morales, L AF Arko, AJ Joyce, JJ Morales, L TI A tunable bench top light source for photoelectron spectroscopy: first results for alpha and delta Pu SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT 4th International School and Symposium on Synchrotron Radiation in Natural Science (ISSRNS 98) CY JUN 15-20, 1998 CL USTRON JASZOWIEC, POLAND DE laser plasma light source; photoemission; plutonium ID ELECTRONS AB We report the first ever utilization of a laser plasma light source for photoelectron spectroscopy. Using a continuous mercury stream as the target, the light source is essentially debris free with intensities rivaling some second generation syncrotrons. Its primary use is likely to be in connection with hazardous materials which are undesirable at synchrotrons, such as Pu. Toward this end we report the first photoemission data on alpha- and delta-Pu. Both phases display a Sf-related feature at E-F, which is much sharper in delta-Pu than in alpha-Pu, suggestive of heavy fermion behavior. In both phases, however, the h nu-dependence of the intensity of this feature can only be understood if there exists substantial 6d-admixture. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Arko, AJ (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 12 TC 13 Z9 13 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD MAY 5 PY 1999 VL 286 IS 1-2 BP 14 EP 19 DI 10.1016/S0925-8388(98)00973-6 PG 6 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 196DM UT WOS:000080293800005 ER PT J AU Ederer, DL Kurmaev, E Shin, S Moewes, A Grush, M Callcott, TA Perera, RCC van Ek, J Stadler, S Winarski, R Terminello, LJ Zhou, L AF Ederer, DL Kurmaev, E Shin, S Moewes, A Grush, M Callcott, TA Perera, RCC van Ek, J Stadler, S Winarski, R Terminello, LJ Zhou, L TI Examples of soft X-ray emission and inelastic scattering excited by synchrotron radiation SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT 4th International School and Symposium on Synchrotron Radiation in Natural Science (ISSRNS 98) CY JUN 15-20, 1998 CL USTRON JASZOWIEC, POLAND DE soft X-ray spectroscopy; X-ray fluorescence; Raman scattering; rare-earth materials; transition metals; photoelectron spectroscopy; density of states ID EXTENDED VANHOVE SINGULARITY; ELECTRONIC-STRUCTURE; FLUORESCENCE SPECTROSCOPY; SUPERCONDUCTOR SR2RUO4; GRATING MONOCHROMATOR; UNDULATOR BEAMLINE; EXCITATION; 4D; RAMAN AB This paper is a summary of some of the recent activities of our soft X-ray spectroscopy collaboration. We are using soft X-ray emission spectroscopy to probe the electronic properties of matter, emphasizing atoms in the bull; and at interfaces. In particular we have used incoherent photon excitation to obtain a basic understanding of the electronic properties of a wide variety of materials including Sr2RuO4, a new superconductor. In this first copperless perovskite superconductor, we confirmed in-plane oxygen-ruthenium bonding by analysis using calculations and soft X-ray emission spectroscopy and photoelectron spectroscopy. In the case of the sulfides, the sulfur in FeCuS occupies a single site, and the sulfur in CuS forms dimers at two thirds of the sites. This behavior was confirmed by calculation and by measurement of soft X-ray emission spectra excited at different photon energies near the sulfur L-2.3 absorption edge, and by core photoemission measurements. Measurements of this type illustrate the importance of combining SXE and PES measurements with theoretical calculations. The ubiquitous presence of Raman scattering near the 3d and 3d ionization thresholds has been used to elucidate the excitation process in a number of rare earth and transition metal compounds. Such scattering can produce dramatic changes in the emission spectrum that can further the basic understanding of the atomic excitation process in these compounds. Photon-in photon-out soft X-ray spectroscopy is adding a new dimension to soft X-ray spectroscopy by providing many opportunities for exciting research, especially at third generation synchrotron light sources. (C) 1999 Published by Elsevier Science S.A. All rights reserved. C1 Tulane Univ, New Orleans, LA 70118 USA. Russian Acad Sci, Inst Met Phys, Ural Div, Yekaterinburg 620219, Russia. Univ Tokyo, Inst Solid State Phys, Tanashi, Tokyo, Japan. Ctr Adv Microstruct & Devices, Baton Rouge, LA 70888 USA. Univ Tennessee, Knoxville, TN 37996 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source, Berkeley, CA 94720 USA. Seagate Technol, Bloomington, MN 55435 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Ederer, DL (reprint author), Tulane Univ, New Orleans, LA 70118 USA. RI Kurmaev, Ernst/J-4254-2013 OI Kurmaev, Ernst/0000-0003-4625-4930 NR 52 TC 0 Z9 0 U1 0 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD MAY 5 PY 1999 VL 286 IS 1-2 BP 47 EP 55 DI 10.1016/S0925-8388(98)00978-5 PG 9 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 196DM UT WOS:000080293800010 ER PT J AU Schindler, JF Naranjo, PA Honaberger, DA Chang, CH Brainard, JR Vanderberg, LA Unkefer, CJ AF Schindler, JF Naranjo, PA Honaberger, DA Chang, CH Brainard, JR Vanderberg, LA Unkefer, CJ TI Haloalkane dehalogenases: Steady-state kinetics and halide inhibition SO BIOCHEMISTRY LA English DT Article ID XANTHOBACTER-AUTOTROPHICUS GJ10; X-RAY STRUCTURE; S(N)2 DISPLACEMENT; ACTIVE-SITE; CATALYTIC MECHANISM; CARBONIC-ANHYDRASE; TRANSITION-STATE; BINDING-SITE; 1,2-DICHLOROETHANE; DEGRADATION AB The substrate specificities and product inhibition patterns of haloalkane dehalogenases from Xanthobacter autotrophicus GJ10 (XaDHL) and Rhodococcus rhodochrous (RrDHL) have been compared using a pH-indicator dye assay. In contrast to XaDHL, RrDHL is efficient toward secondary allyl halides. Using steady-state kinetics, we have shown that halides are uncompetitive inhibitors of XaDHL with 1,2-dichloroethane as the varied substrate at pH 8.2 (Cl-, K-ii = 19 +/- 0.91; Br-, K-ii = 2.5 +/- 0.19 mM; I-, K-ii = 4.1 +/- 0.43 mM). Because they are uncompetitive with the substrate, halide ions do not bind to the free form of the enzyme; therefore, halide ions cannot be the last product released from the enzyme. The K-ii for chloride was pH dependent and decreased more than 20-fold from 61 mM at pH 8.9 to 2.9 mM at pH 6.5. The pH dependence of 1/K-ii showed simple titration behavior that fit to a pK(a) of approximately 7.5. The k(cat) was maximal at pH 8.2 and decreased at lower pH. A titration of k(cat) versus pH also fits to a pK(a) of approximately 7.5. Taken together, these data suggest that chloride binding and k(cat) are affected by the same ionizable group, likely the imidazole of a histidyl residue. In contrast, halides do not inhibit RrDHL. The Rhodococcus enzyme does not contain a tryptophan corresponding to W175 of XaDHL, which has been implicated in halide ion binding. The site-directed mutants W175F and W175Y of XaDHL were prepared and tested for halide ion inhibition. Halides do not inhibit either W175F or W175Y XaDHL. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Biosci & Biotechnol Grp, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. RP Unkefer, CJ (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Biosci & Biotechnol Grp, POB 1663, Los Alamos, NM 87545 USA. NR 32 TC 50 Z9 51 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD MAY 4 PY 1999 VL 38 IS 18 BP 5772 EP 5778 DI 10.1021/bi982853y PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 193YP UT WOS:000080165600012 PM 10231528 ER PT J AU Barycki, JJ O'Brien, LK Bratt, JM Zhang, RG Sanishvili, R Strauss, AW Banaszak, LJ AF Barycki, JJ O'Brien, LK Bratt, JM Zhang, RG Sanishvili, R Strauss, AW Banaszak, LJ TI Biochemical characterization and crystal structure determination of human heart short chain L-3-Hydroxyacyl-CoA dehydrogenase provide insights into catalytic mechanism SO BIOCHEMISTRY LA English DT Article ID FATTY-ACID OXIDATION; LARGE ALPHA-SUBUNIT; 3-HYDROXYACYL-COA DEHYDROGENASE; ESCHERICHIA-COLI; ANGSTROM RESOLUTION; MULTIENZYME COMPLEX; SUBSTRATE-BINDING; A DEHYDROGENASE; RAT-LIVER; COENZYME AB Human heart short chain L-3-hydroxyacyl-CoA dehydrogenase(SCHAD) catalyzes the oxidation of the hydroxyl group of L-3-hydroxyacyl-CoA to a keto group, concomitant with the reduction of NAD(+) to NADH, as part of the beta-oxidation pathway. The homodimeric enzyme has been overexpressed in Escherichia coli, purified to homogeneity, and studied using biochemical and crystallographic techniques. The dissociation constants of NAD(+) and NADH have been determined over a broad pH range and indicate that SCHAD binds reduced cofactor preferentially. Examination of apparent catalytic constants reveals that SCHAD displays optimal enzymatic activity near neutral pH, with catalytic efficiency diminishing rapidly toward pH extremes. The crystal structure of SCHAD complexed with NAD(+) has been solved using multiwavelength anomalous diffraction techniques and a selenomethionine-substituted analogue of the enzyme. The subunit structure is comprised of two domains. The first domain is similar to other alpha/beta dinucleotide folds but includes an unusual helix-turn-helix motif which extends from the central beta-sheet. The second, or C-terminal, domain is primarily alpha-helical and mediates subunit dimerization and, presumably, L-3-hydroxyacyl-CoA binding. Molecular modeling studies in which L-3-hydroxybutyryl-CoA was docked into the enzyme-NAD(+) complex suggest that His 158 serves as a general base, abstracting a proton from the 3-OH group of the substrate. Furthermore, the ability of His 158 to perform such a function may be enhanced by an electrostatic interaction with Glu 170, consistent with previous biochemical observations. These studies provide further understanding of the molecular basis of several inherited metabolic disease states correlated with L-3-hydroxyacyl-CoA dehydrogenase deficiencies. C1 Univ Minnesota, Dept Biochem Mol Biol & Biophys, Minneapolis, MN 55455 USA. Washington Univ, Sch Med, Dept Pediat, St Louis, MO 63110 USA. Argonne Natl Lab, Ctr Mech Biol & Biotechnol, Struct Biol Ctr, Argonne, IL 60439 USA. RP Banaszak, LJ (reprint author), Univ Minnesota, Dept Biochem Mol Biol & Biophys, 4-225 Millard hall,435 Delaware St SE, Minneapolis, MN 55455 USA. FU NIDDK NIH HHS [1F32-DK09759-01]; NIGMS NIH HHS [GM13925] NR 34 TC 71 Z9 74 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD MAY 4 PY 1999 VL 38 IS 18 BP 5786 EP 5798 DI 10.1021/bi9829027 PG 13 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 193YP UT WOS:000080165600014 PM 10231530 ER PT J AU Reckless, J Rubin, EM Verstuyft, JB Metcalfe, JC Grainger, DJ AF Reckless, J Rubin, EM Verstuyft, JB Metcalfe, JC Grainger, DJ TI Monocyte chemoattractant protein-1 but not tumor necrosis factor-alpha is correlated with monocyte infiltration in mouse lipid lesions SO CIRCULATION LA English DT Article DE atherosclerosis; monocytes; aorta; lipids; lesion ID TRANSGENIC APOLIPOPROTEIN(A) MICE; GROWTH-FACTOR-BETA; ATHEROSCLEROTIC LESIONS; DENSITY-LIPOPROTEIN; STRAINS C57BL/6; DEFICIENT MICE; ARTERIAL-WALL; ADHESION; CELLS; EXPRESSION AB Background-Apolipoprotein (apo)(a) transgenic mice and C57BL/6 mice fed a high fat diet develop similar-sized lipid lesions, but lesions in apo(a) mice are devoid of macrophages, We used this observation to identify which proinflammatory proteins might be involved in mediating monocyte recruitment during atherogenesis. Methods and Results-Macrophage-deficient apo(a) transgenic mouse lesions contained similar levels of several different proinflammatory proteins, both adhesion molecules (intercellular adhesion molecule-1 [ICAM-1] and vascular cell adhesion molecule-1 [VCAM-1]) and cytokines (tumor necrosis factor-alpha [TNF-alpha] and macrophage inflammatory protein-1 alpha [MIP-1 alpha]), similar to the macrophage-rich lesions of C57BL/6 mice. Conclusions-From this we conclude that ICAM-1, VCAM-1. TNF-alpha, and MIP-1 alpha may all be necessary for vascular monocyte recruitment in vivo, but they cannot be sufficient. Monocyte chemoattractant protein-1 (MCP-1) protein was undetectable in the vessel wall taken from apo(a) transgenic mice fed a high fat diet compared with high expression in mice with lipid lesions (C57BL/6 and apoE knockout mice). Therefore elevated expression of MCP-1 but not TNF-alpha, MIP-1 alpha, ICAM-1, or VCAM-1 is correlated with vascular macrophage accumulation. To test the hypothesis that monocyte infiltration during atherogenesis is MCP-1 dependent, it will be necessary to develop specific pharmacological inhibitors of MCP-1 activity. C1 Univ Cambridge, Dept Biochem, Cambridge CB2 1QW, England. Univ Cambridge, Dept Med, Cambridge CB2 1QW, England. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA USA. RP Reckless, J (reprint author), Univ Cambridge, Addenbrookes Hosp, Dept Med, Box 157,Hills Rd, Cambridge CB2 2QQ, England. FU Wellcome Trust NR 49 TC 55 Z9 56 U1 0 U2 4 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0009-7322 J9 CIRCULATION JI Circulation PD MAY 4 PY 1999 VL 99 IS 17 BP 2310 EP 2316 PG 7 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 191CW UT WOS:000080004900015 PM 10226098 ER PT J AU Agamalian, M Alamo, RG Kim, MH Londono, JD Mandelkern, L Wignall, GD AF Agamalian, M Alamo, RG Kim, MH Londono, JD Mandelkern, L Wignall, GD TI Phase behavior of blends of linear and branched polyethylenes on micron length scales via ultra-small-angle neutron scattering SO MACROMOLECULES LA English DT Article ID LOW-DENSITY POLYETHYLENE; THERMODYNAMIC INTERACTIONS; POLYMER BLENDS; SEGREGATION; SEPARATION; MIXTURES; MOLTEN; CHAIN; STATE; MELT AB Small-angle neutron scattering (SANS) experiments have indicated that mixtures of linear thigh density) and long chain branched (low density) polyethylenes (HDPE/LDPE) form a one-phase mixture in the melt. However, the maximum spatial resolution of pinhole SANS cameras is similar to 10(3) Angstrom, and it has been suggested that such experiments do not provide unambiguous evidence for a homogeneous melt. Thus, the SANS data might also be interpreted as arising from a biphasic melt with a very large particle size (similar to 3 mu m), because most of the scattering from the different phases mould not be resolved. We have addressed this hypothesis by means of ultra-small-angle neutron scattering (USANS) experiments, using a newly developed Bonse-Hart USANS facility, which can resolve particle dimensions up to 30 mu m. The experiments confirm that HDPE/LDPE blends are homogeneous in the melt on length scales probed by pinhole SANS and also by USANS. We have also studied blends of linear and short-chain branched polyethylenes, which phase separate when the branch content is sufficiently high. It is shown that USANS can directly resolve both the size of the dispersed phase (similar to 4 mu m) and the forward cross section [d Sigma/d Omega(0) similar to 10(8) cm(-1)], which is 6 orders of magnitude higher than for homogeneous blends. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37830 USA. Florida Agr & Mech Univ, Dept Chem Engn, Tallahassee, FL 32310 USA. Florida State Univ, Coll Engn, Tallahassee, FL 32310 USA. Florida State Univ, Inst Mol Biophys, Tallahassee, FL 32306 USA. RP Agamalian, M (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37830 USA. OI Wignall, George/0000-0002-3876-3244; Agamalian, Michael/0000-0002-9112-2534 NR 33 TC 48 Z9 48 U1 0 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD MAY 4 PY 1999 VL 32 IS 9 BP 3093 EP 3096 DI 10.1021/ma981091b PG 4 WC Polymer Science SC Polymer Science GA 194EM UT WOS:000080179200038 ER PT J AU Izaurralde, RC Rosenberg, NJ Brown, RA Legler, DM Lopez, MT Srinivasan, R AF Izaurralde, RC Rosenberg, NJ Brown, RA Legler, DM Lopez, MT Srinivasan, R TI Modeled effects of moderate and strong 'Los Ninos' on crop productivity in North America SO AGRICULTURAL AND FOREST METEOROLOGY LA English DT Article DE El Nino; El Nino Southern Oscillation (ENSO); EPIC; corn; wheat ID EPIC MODEL; CLIMATE; YIELD; CO2 AB The El Nino of 1997-1998 rivaled in strength that of 1982-1983 and called attention worldwide not only for that reason but also because advances in understanding of ENSO phenomena allowed for its early forecast and preparations to deal with its impacts. We used the Erosion Productivity Impact Calculator (EPIC) to evaluate the impacts of El Nino on North American agriculture through an assemblage of 140 representative farms. We distinguish between 'regular' (EN) and 'strong' (SEN) Fl Nino defined by the extent to which sea surface temperatures in the central and eastern tropical Pacific ocean deviate from the long term normal. Each condition produced a distinct geographic distribution of temperature and precipitation anomalies with respect to Neutral (N) years (within 0.5 degrees C of the long term normal). Using daily weather records, EPIC accounted for 87% of the total variation in historical yields in a sample of the farms. Yields simulated in EPIC with a stochastic weather generator predicted different geographic distributions of 'winner' and 'loser' regions for corn and wheat during EN and SEN years. Changes in water stress during EN and SEN with respect to N years was the variable that accounted for a significant proportion in the variation of simulated yield changes. Yields simulated under SEN tended to have larger variability than under EN. Further evaluation of the methodology presented here could arise from the near real-time simulation of Fl Nino events. Application of this type of methodology at a regional level could take advantage of interannual climatic variability for agricultural production. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Battelle Pacific NW Natl Lab, Washington, DC 20024 USA. Florida State Univ, Ctr Ocean Atmospher Predict Studies, Tallahassee, FL 32306 USA. Inst Invest Forestales & Agropecuarias, Morelia 58260, Michoacan, Mexico. Texas A&M Univ, Blackland Res Ctr, Temple, TX 76502 USA. RP Izaurralde, RC (reprint author), Battelle Pacific NW Natl Lab, 901 D St,SW,Suite 900, Washington, DC 20024 USA. RI Izaurralde, Roberto/E-5826-2012; Srinivasan, R/D-3937-2009 NR 21 TC 20 Z9 21 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-1923 J9 AGR FOREST METEOROL JI Agric. For. Meteorol. PD MAY 3 PY 1999 VL 94 IS 3-4 BP 259 EP 268 DI 10.1016/S0168-1923(98)00128-2 PG 10 WC Agronomy; Forestry; Meteorology & Atmospheric Sciences SC Agriculture; Forestry; Meteorology & Atmospheric Sciences GA 194RD UT WOS:000080206600008 ER PT J AU Allen, CW Birtcher, RC Donnelly, SE Furuya, K Ishikawa, N Song, M AF Allen, CW Birtcher, RC Donnelly, SE Furuya, K Ishikawa, N Song, M TI Migration and coalescence of Xe nanoprecipitates in Al induced by electron irradiation at 300 K SO APPLIED PHYSICS LETTERS LA English DT Article ID HELIUM BUBBLES; ALUMINUM AB Effects of 1 MeV electron irradiation on Xe precipitates in Al, formed by ion implantation, have been observed in situ by high-voltage transmission electron microscopy. Individual Xe precipitates undergo melting and recrystallization, migration which leads to coalescence, and shape changes. These processes are driven by the production of defects without either cascade defect production or the introduction of additional Xe atoms. Precipitate migration is due to an irradiation-induced surface diffusion process on the Xe/Al interfaces. Coalescence of close precipitates is enhanced by directed motion as a result of the net displacement of Al atoms out of the volume between them. (C) 1999 American Institute of Physics. [S0003-6951(99)03818-8]. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Univ Salford, Joule Phys Lab, Salford M5 4WT, Lancs, England. Natl Res Inst Met, High Resolut Beam Labs, Tsukuba, Ibaraki 305, Japan. RP Allen, CW (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. OI Donnelly, Stephen/0000-0002-9749-5550 NR 11 TC 25 Z9 25 U1 1 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 3 PY 1999 VL 74 IS 18 BP 2611 EP 2613 DI 10.1063/1.123913 PG 3 WC Physics, Applied SC Physics GA 190PE UT WOS:000079972400015 ER PT J AU Jimenez, I Tong, WM Shuh, DK Holloway, BC Kelly, MA Pianetta, P Terminello, LJ Himpsel, FJ AF Jimenez, I Tong, WM Shuh, DK Holloway, BC Kelly, MA Pianetta, P Terminello, LJ Himpsel, FJ TI Bonding modifications in carbon nitride films induced by thermal annealing: An x-ray absorption near edge study SO APPLIED PHYSICS LETTERS LA English DT Article ID CATHODIC ARC DEPOSITION; THIN-FILMS; NITROGEN; SOLIDS; XANES AB The thermal stability of nonstoichiometric carbon nitride films has been studied by x-ray absorption near edge spectroscopy. Amorphous carbon nitride thin films were annealed in vacuum up to 1150 degrees C revealing the presence of nitrogen in different bonding configurations. Annealing to 450 degrees C results in the loss of similar to 50% of the nitrogen. The remaining nitrogen is bonded to carbon within a graphitic framework and it evolves into a more stable configuration with increasing temperature without significant N loss up to 820 degrees C. Beyond this temperature, nitrogen loss occurs without important structural changes. (C) 1999 American Institute of Physics. [S0003-6951(99)01918-X]. C1 CSIC, Inst Ciencia Mat, E-28049 Madrid, Spain. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Stanford Univ, Stanford, CA 94305 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. RP Jimenez, I (reprint author), CSIC, Inst Ciencia Mat, E-28049 Madrid, Spain. RI Jimenez, Ignacio/F-7422-2010; Tong, William/D-2564-2010 OI Jimenez, Ignacio/0000-0001-5605-3185; NR 16 TC 49 Z9 49 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 3 PY 1999 VL 74 IS 18 BP 2620 EP 2622 PG 3 WC Physics, Applied SC Physics GA 190PE UT WOS:000079972400018 ER PT J AU Browning, ND Buban, JP Moltaji, HO Pennycook, SJ Duscher, G Johnson, KD Rodrigues, RP Dravid, VP AF Browning, ND Buban, JP Moltaji, HO Pennycook, SJ Duscher, G Johnson, KD Rodrigues, RP Dravid, VP TI The influence of atomic structure on the formation of electrical barriers at grain boundaries in SrTiO3 SO APPLIED PHYSICS LETTERS LA English DT Article ID OXIDES AB An experimental atomic resolution analysis of an undoped Sigma 5 36 degrees [001] tilt grain boundary in SrTiO3 shows that the structure contains incomplete oxygen octahedra. These incomplete octahedra act as effective oxygen vacancies and lead to a fixed, positive boundary charge. Annealing the boundary in the presence of MnO2 does not change the atomic structure of the boundary plane, and results in a high concentration of Mn3+ (acceptor) enrichment at the specific Ti4+ locations in closest proximity to the effective oxygen vacancies. This result can be explained in terms of standard charge compensation models and indicates that the formation of electrical barriers at oxide grain boundaries may be influenced by the atomic structure of the boundary plane. (C) 1999 American Institute of Physics. [S0003-6951(99)00618-X]. C1 Univ Illinois, Dept Phys, Chicago, IL 60607 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. RP Browning, ND (reprint author), Univ Illinois, Dept Phys, Chicago, IL 60607 USA. RI Dravid, Vinayak/B-6688-2009; Duscher, Gerd/G-1730-2014; OI Duscher, Gerd/0000-0002-2039-548X; Browning, Nigel/0000-0003-0491-251X NR 14 TC 76 Z9 77 U1 2 U2 25 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 3 PY 1999 VL 74 IS 18 BP 2638 EP 2640 DI 10.1063/1.123922 PG 3 WC Physics, Applied SC Physics GA 190PE UT WOS:000079972400024 ER PT J AU Bertram, D Hanna, MC Nozik, AJ AF Bertram, D Hanna, MC Nozik, AJ TI Two color blinking of single strain-induced GaAs quantum dots SO APPLIED PHYSICS LETTERS LA English DT Article ID EXCITED-STATES; LUMINESCENCE; STRESSORS; WELL; CONFINEMENT; GROWTH AB In this letter we report on a temporal instability in the ground and excited state luminescence of a single strain-induced quantum dot. Using a microscopic photoluminescence technique, we record spectra from a single strain-induced quantum dot in the GaAs/(AlGa)As material system. On a time scale of seconds the luminescence shows an increase and decrease in intensity with an increase of the ground state luminescence correlating with a decrease in the excited state luminescence intensity and vice versa. We term the observed effect two color blinking. (C) 1999 American Institute of Physics. [S0003-6951(99)02318-9]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Bertram, D (reprint author), Philips Res Labs, Weisshausstr 2, D-52066 Aachen, Germany. RI Nozik, Arthur/A-1481-2012; Nozik, Arthur/P-2641-2016 NR 25 TC 37 Z9 37 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 3 PY 1999 VL 74 IS 18 BP 2666 EP 2668 DI 10.1063/1.123932 PG 3 WC Physics, Applied SC Physics GA 190PE UT WOS:000079972400034 ER PT J AU Duewer, F Gao, C Takeuchi, I Xiang, XD AF Duewer, F Gao, C Takeuchi, I Xiang, XD TI Tip-sample distance feedback control in a scanning evanescent microwave microscope SO APPLIED PHYSICS LETTERS LA English DT Article ID NEAR-FIELD MICROSCOPY; FERROELECTRIC DOMAINS; FORCE AB We have developed a means of tip-sample distance regulation for a scanning evanescent microwave microscope over conductive samples. Changes in resonant frequency and quality factor are measured, where changes in resonant frequency are related to the tip-sample capacitance and changes in quality factor are related to microwave absorption. With the analytical expression of the tip-sample capacitance as a function of tip-sample distance, we can quantitatively regulate the tip-sample separation. We demonstrated simultaneous noncontact imaging of topography and surface resistance with high spatial resolution. (C) 1999 American Institute of Physics. [S0003-6951(99)03518-4]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Xiang, XD (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Xiang, Xiaodong/A-9445-2012; Xiang, Xiaodong/A-5936-2017 NR 10 TC 34 Z9 35 U1 1 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 3 PY 1999 VL 74 IS 18 BP 2696 EP 2698 DI 10.1063/1.123940 PG 3 WC Physics, Applied SC Physics GA 190PE UT WOS:000079972400044 ER PT J AU Han, J Baca, AG Shul, RJ Willison, CG Zhang, L Ren, F Zhang, AP Dang, GT Donovan, SM Cao, XA Cho, H Jung, KB Abernathy, CR Pearton, SJ Wilson, RG AF Han, J Baca, AG Shul, RJ Willison, CG Zhang, L Ren, F Zhang, AP Dang, GT Donovan, SM Cao, XA Cho, H Jung, KB Abernathy, CR Pearton, SJ Wilson, RG TI Growth and fabrication of GaN/AlGaN heterojunction bipolar transistor SO APPLIED PHYSICS LETTERS LA English DT Article ID CHEMICAL-VAPOR-DEPOSITION; FIELD-EFFECT TRANSISTORS; GAN; ELECTRONICS; MODFETS AB A GaN/AlGaN heterojunction bipolar transistor structure with Mg doping in the base and Si doping in the emitter and collector regions was grown by metalorganic chemical vapor deposition on c-axis Al2O3. Secondary ion mass spectrometry measurements showed no increase in the O concentration (2-3 x 10(18) cm(-3)) in the AlGaN emitter and fairly low levels of C (similar to 4 - 5 x 10(17) cm(-3)) throughout the structure. Due to the nonohmic behavior of the base contact at room temperature, the current gain of large area (similar to 90 mm diameter) devices was <3. Increasing the device operating temperature led to higher ionization fractions of the Mg acceptors in the base, and current gains of similar to 10 were obtained at 300 degrees C. (C) 1999 American Institute of Physics. [S0003-6951(99)02218-4]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. RP Han, J (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 26 TC 72 Z9 75 U1 0 U2 13 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 3 PY 1999 VL 74 IS 18 BP 2702 EP 2704 DI 10.1063/1.123942 PG 3 WC Physics, Applied SC Physics GA 190PE UT WOS:000079972400046 ER PT J AU Metzger, H Chen, HX Goldstein, B Haleem-Smith, H Inman, JK Peirce, M Torigoe, C Vonakis, B Wofsy, C AF Metzger, H Chen, HX Goldstein, B Haleem-Smith, H Inman, JK Peirce, M Torigoe, C Vonakis, B Wofsy, C TI A quantitative approach to signal transduction SO IMMUNOLOGY LETTERS LA English DT Article; Proceedings Paper CT 10th Symposium on Signals and Signal Processing in the Immune System CY SEP 13-17, 1998 CL BALATONOSZOD, HUNGARY DE IgE receptor; tyrosine phosphorylation; membrane receptors ID AFFINITY IGE RECEPTOR; PROTEIN-TYROSINE PHOSPHATASES; IMMUNOGLOBULIN-E; KINASE; CELLS; PHOSPHORYLATION; AGGREGATION; MECHANISM; ASSOCIATION; SYK AB The high affinity receptor for IgE (Fc epsilon RI), is one of a family of immunoreceptors whose antigen-induced clustering leads to a variety of cellular responses. The signaling pathways are enormously complex but by focusing on only the most initial steps, it is now possible to sketch plausible molecular models that relate the interaction of multivalent antigens with the receptor-bound IgE to the earliest cellular events. In this paper, we describe how we have combined quantitative experimentation and mathematical modeling to probe this system further. We also discuss some of the formidable challenges that remain before we can claim reasonably complete understanding of even these early events. (C) 1999 Elsevier Science B.V. All rights reserved. C1 NIAMS, Arthritis & Rheumatism Branch, NIH, Bethesda, MD 20892 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. NIAID, Immunol Lab, NIH, Bethesda, MD 20892 USA. Univ New Mexico, Dept Math, Albuquerque, NM 87131 USA. RP Metzger, H (reprint author), NIAMS, Arthritis & Rheumatism Branch, NIH, Bldg 10,Room 9N-228,10 Ctr Dr MSC 1820, Bethesda, MD 20892 USA. NR 28 TC 8 Z9 8 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-2478 J9 IMMUNOL LETT JI Immunol. Lett. PD MAY 3 PY 1999 VL 68 IS 1 BP 53 EP 57 DI 10.1016/S0165-2478(99)00030-9 PG 5 WC Immunology SC Immunology GA 206BG UT WOS:000080855700008 PM 10397156 ER PT J AU Collman, JP Harford, ST Franzen, S Marchon, JC Maldivi, P Shreve, AP Woodruff, WH AF Collman, JP Harford, ST Franzen, S Marchon, JC Maldivi, P Shreve, AP Woodruff, WH TI Resonance Raman, X-ray crystallographic, and magnetic susceptibility studies of metal-metal-bonded MoRu and WOs porphyrin dimers. 1. Evidence for an unusual MO diagram SO INORGANIC CHEMISTRY LA English DT Article ID 2-HYDROXYPYRIDINATE COMPLEXES; STRUCTURAL CHARACTERIZATION; QUADRUPLE BONDS; MULTIPLE BONDS; RUTHENIUM; MOLYBDENUM; SPECTRA; TETRAPHENYLPORPHYRIN; DIRUTHENIUM(II); DERIVATIVES AB Solution (VT NMR, Evans method magnetic susceptibility, resonance Raman) and solid-state (SQUID magnetic susceptibility, X-ray crystallography) spectroscopic studies of intertriad heterodimeric [(OEP)MoRu(OEP)] (1), [(OEP)WOs(OEP)] (2), and [(OEP)MoRu(TPP)]PF6 (3(+)) metalloporphyrins are reported (OEP = 2,3,7,8,12,13,17,18-octaethylporphyrinato; TPP = 5,10,1 5,20-tetraphenylporphyrinato). Solution and solid-state magnetic susceptibility data indicate that 1 and 2 contain two unpaired electrons in the ground electronic configuration. The presence of a delta bond in 3(+) has been confirmed by structural characterization: The experimental evidence is consistent with a molecular orbital ordering, sigma < pi < delta < pi* < delta*, which is different from that seen for homologous metalloporphyrin dimers with homometallic or intratriad heterometallic multiple metal-metal bonds. Resonance Raman data suggest that the heterometallic bonds are slightly stronger than isoelectronic homometallic species. C1 Stanford Univ, Dept Chem, Stanford, CA 94305 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. CEA Grenoble, SCIB, Dept Rech Fondamentale Mat Condensee, F-38054 Grenoble, France. RP Collman, JP (reprint author), Stanford Univ, Dept Chem, Stanford, CA 94305 USA. NR 37 TC 10 Z9 10 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD MAY 3 PY 1999 VL 38 IS 9 BP 2085 EP 2092 DI 10.1021/ic981032e PG 8 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 194LG UT WOS:000080194500021 ER PT J AU Collman, JP Harford, ST Franzen, S Shreve, AP Woodruff, WH AF Collman, JP Harford, ST Franzen, S Shreve, AP Woodruff, WH TI Resonance Raman and X-ray crystallographic studies of intertriad metal-metal bonds. 2. WRu and MoOs porphyrin dimers SO INORGANIC CHEMISTRY LA English DT Article ID QUADRUPLE BONDS; MULTIPLE BONDS; RUTHENIUM; MOLYBDENUM; DERIVATIVES; COMPLEXES; SPECTRA AB Solution (H-1 NMR, Evans method magnetic susceptibility, resonance Raman) and X-ray crystallographic spectroscopic studies of intertriad heterodimeric [(OEP)MoOs(OEP)] (3), [(OEP)WRu(OEP)] (4), [(OEP)MoOs(TPP)]PF6 (5(+)), and [(OEP)WRu(TPP)]PF6 (6(+)) metalloporphyrins are reported (OEP = 2,3,7,8,12,13,17,18-octaethylporphyrinato; TPP = 5,10,15,20-tetraphenylporphyrinato). Evans method magnetic susceptibility data indicate that 3 and 4 contain two unpaired electrons in the ground electronic configuration. Resonance Raman spectra of 3, 4, 5(+), and 6(+) suggest that WRu bonds are 5-10% stronger than corresponding MoOs species. Structural characterization of 5(+) and 6(+) demonstrates metal-metal bond lengths of 2.30 (WRu) and 2.24 (MoOs) Angstrom, respectively. The possibility of a special stability associated with polar heterometallic multiple bonds is discussed. C1 Stanford Univ, Dept Chem, Stanford, CA 94305 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Collman, JP (reprint author), Stanford Univ, Dept Chem, Stanford, CA 94305 USA. NR 22 TC 10 Z9 10 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD MAY 3 PY 1999 VL 38 IS 9 BP 2093 EP 2097 DI 10.1021/ic9810337 PG 5 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 194LG UT WOS:000080194500022 ER PT J AU Kadish, KM Van Caemelbecke, E D'Souza, F Lin, M Nurco, DJ Medforth, CJ Forsyth, TP Krattinger, B Smith, KM Fukuzumi, S Nakanishi, I Shelnutt, JA AF Kadish, KM Van Caemelbecke, E D'Souza, F Lin, M Nurco, DJ Medforth, CJ Forsyth, TP Krattinger, B Smith, KM Fukuzumi, S Nakanishi, I Shelnutt, JA TI Synthesis and electrochemical studies of a series of fluorinated dodecaphenylporphyrins SO INORGANIC CHEMISTRY LA English DT Article ID HIGHLY SUBSTITUTED PORPHYRINS; NONPLANAR PORPHYRINS; SPECTRAL CHARACTERIZATION; REDOX POTENTIALS; IRON PORPHYRINS; RING DISTORTION; TETRAPHENYLPORPHYRINS; METALLOPORPHYRINS; OXIDATION; NITROALKENES AB Dodecaphenylporphyrins with varying degrees of fluorination of the peripheral phenyl rings (F(x)DPPs) were synthesized as model compounds for studying electronic effects in nonplanar porphyrins, and detailed electrochemical studies of the chloroiron(III) complexes of these compounds were undertaken. The series of porphyrins, represented as FeDPPCl and as FeF(x)DPPCl where x = 4, 8 (two isomers), 12, 20, 28, or 36, could be reversibly oxidized by two successive one-electron transfer steps in dichloromethane to give pi-cation radicals and pi-dications, respectively. All of the compounds investigated could also be reduced by three electrons in benzonitrile or pyridine. In benzonitrile, three reversible reductions were observed for the unfluorinated compound FeDPPCl, whereas the FeF(x)DPPCl complexes generally exhibited irreversible first and second reductions which were coupled to chemical reactions. The chemical reaction associated with the first reduction involved a loss of the chloride ion after generation of [Fe(II)F(x)DPPCl](-). The second chemical reaction involved a conversion between the initially generated Fe(II) porphyrin pi-anion radical and the final Fe(I) porphyrin reduction product. In pyridine, three reversible one-electron reductions were observed with the second reduction affording stable Fe(II) porphyrin pi-anion radicals for all of the complexes investigated. C1 Univ Houston, Dept Chem, Houston, TX 77204 USA. Univ Calif Davis, Dept Chem, Davis, CA 95616 USA. Osaka Univ, Dept Mat & Life Sci, Suita, Osaka 5650871, Japan. Sandia Natl Labs, Mat Theory & Computat Dept, Albuquerque, NM 87185 USA. Univ New Mexico, Dept Chem, Albuquerque, NM 87131 USA. RP Kadish, KM (reprint author), Univ Houston, Dept Chem, Univ Pk, Houston, TX 77204 USA. RI Shelnutt, John/A-9987-2009; Smith, Kevin/G-1453-2011; Fukuzumi, Shunichi /E-4728-2010; Nakanishi, Ikuo/E-4430-2012; Medforth, Craig/D-8210-2013; REQUIMTE, FMN/M-5611-2013; REQUIMTE, UCIBIO/N-9846-2013 OI Shelnutt, John/0000-0001-7368-582X; Smith, Kevin/0000-0002-6736-4779; Nakanishi, Ikuo/0000-0001-9204-0664; Medforth, Craig/0000-0003-3046-4909; NR 53 TC 49 Z9 49 U1 0 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD MAY 3 PY 1999 VL 38 IS 9 BP 2188 EP 2198 DI 10.1021/ic9811695 PG 11 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 194LG UT WOS:000080194500036 ER PT J AU Yi, YS Bishop, AR Roder, H AF Yi, YS Bishop, AR Roder, H TI Spin-Peierls ground states in an electron-lattice periodic Anderson model SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID HEAVY-FERMION COMPOUNDS; HUBBARD MODEL; MONTE-CARLO; TRANSITION; CUPRATE; CUGEO3; SYSTEMS; ORDER AB Novel dimerized antiferromagnetic (homogeneous spin-Peierls) and inhomogeneous-lattice antiferromagnetic (inhomogeneous spin-Peierls) ground states are found in a one-dimensional (I-D) and a two-dimensional (2-D) electron-lattice periodic Anderson model, respectively. Coexistence and mutual enhancement of the Peierls lattice distortion and the anti-ferromagnetic long-range-order are emphasized. The stoichiometric (half-filling) phase diagrams for the I-D and 2-D cases are strongly dependent on the hybridization and electron-lattice coupling. For non-stoichiometric fillings, local lattice distortion (coupled spin-charge-lattice small-polaron) states are found: these are discussed in the context of, for example, Ce-based, heavy-fermion systems. Relations to volume collapse phenomena and inorganic spin-Peierls systems, and the similarity of the phase diagrams to those of organic superconductors are also described. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. RP Yi, YS (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 25 TC 7 Z9 7 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD MAY 3 PY 1999 VL 11 IS 17 BP 3547 EP 3554 DI 10.1088/0953-8984/11/17/312 PG 8 WC Physics, Condensed Matter SC Physics GA 193UB UT WOS:000080154600014 ER PT J AU Abe, F Akimoto, H Akopian, A Albrow, MG Amadon, A Amendolia, SR Amidei, D Antos, J Aota, S Apollinari, G Arisawa, T Asakawa, T Ashmanskas, W Atac, M Azzi-Bacchetta, P Bacchetta, N Bagdasarov, S Bailey, MW de Barbaro, P Barbaro-Galtieri, A Barnes, VE Barnett, BA Barone, M Bauer, G Baumann, T Bedeschi, F Behrends, S Belforte, S Bellettini, G Bellinger, J Benjamin, D Bensinger, J Beretvas, A Berge, JP Berryhill, J Bertolucci, S Bettelli, S Bevensee, B Bhatti, A Biery, K Bigongiari, C Binkley, M Bisello, D Blair, RE Blocker, C Bloom, K Busk, S Bodek, A Bokhari, W Bolla, G Bonushkin, Y Bortoletto, D Boudreau, J Brandl, A Breccia, L Bromberg, C Bruner, N Brunetti, R Buckley-Geer, E Budd, HS Burkett, K Busetto, G Byon-Wagner, A Byrum, KL Campbell, M Caner, A Carithers, W Carlsmith, D Cassada, J Castro, A Cauz, D Ceni, A Cerri, A Chang, PS Chang, PT Chao, HY Chapman, J Cheng, MT Chertok, M Chiarelli, G Chiou, CN Chlebana, F Christofek, L Cropp, R Chu, ML Cihangir, S Clark, AG Cobal, M Cocca, E Contreras, M Conway, J Cooper, J Cordelli, M Costanzo, D Couyoumtzelis, C Cronin-Hennessy, D Culbertson, R Dagenhart, D Daniels, T DeJongh, F Dell'Agnello, S Dell'Orso, M Demina, R Demortier, L Deninno, M Derwent, PF Devlin, T Dittmann, JR Donati, S Done, J Dorigo, T Eddy, N Einsweiler, K Elias, JE Ely, R Engels, E Erdmann, W Errede, D Errede, S Fan, Q Feild, RG Feng, Z Ferretti, C Fiori, I Flaugher, B Foster, GW Franklin, M Freeman, J Friedman, J Fukui, Y Gadomski, S Galeotti, S Gallinaro, M Ganel, O Garcia-Sciveres, M Garfinkel, AF Gay, C Geer, S Gerdes, DW Giannetti, P Giokaris, N Giromini, P Giusti, G Gold, M Gordon, A Goshaw, AT Gotra, Y Goulianos, K Grassmann, H Green, C Groer, L Grosso-Pilcher, C Guillian, G da Costa, JG Guo, RS Haber, C Hafen, E Hahn, SR Hamilton, R Handa, T Handler, R Hao, W Happacher, F Hara, K Hardman, AD Harris, RM Hartmann, F Hauser, J Hayashi, E Heinrich, J Heiss, A Hinrichsen, B Hoffman, KD Holck, C Hollebeek, R Holloway, L Huang, Z Huffman, BT Hughes, R Huston, J Huth, J Ikeda, H Incagli, M Incandela, J Introzzi, G Iwai, J Iwata, Y James, E Jensen, H Joshi, U Kajfasz, E Kambara, H Kamon, T Kaneko, T Karr, K Kasha, H Kato, Y Keaffaber, TA Kelley, K Kennedy, RD Kephart, R Kestenbaum, D Khazins, D Kikuchi, T Kirk, M Kim, BJ Kim, HS Kim, SH Kim, YK Kirsch, L Klimenko, S Knoblauch, D Koehn, P Kongeter, A Kondo, K Konigsberg, J Kordas, K Korytov, A Kovacs, E Kowald, W Kroll, J Kruse, M Kuhlmann, SE Kuns, E Kurino, K Kuwabara, T Laasanen, AT Lami, S Lammel, S Lamoureux, JI Lancaster, M Lanzoni, M Latino, G LeCompte, T Leone, S Lewis, JD Lindgren, M Liss, TM Liu, JB Liu, YC Lockyer, N Long, O Loreti, M Lucchesi, D Lukens, P Lusin, S Lys, J Maeshima, K Maksimovic, P Mangano, M Mariotti, M Marriner, JP Martignon, G Martin, A Matthews, JAJ Mazzanti, P McFarland, K McIntyre, P Melese, P Menguzzato, M Menzione, A Meschi, E Metzler, S Miao, C Miao, T Michail, G Miller, R Minato, H Miscetti, S Mishina, M Miyashita, S Moggi, N Moore, E Morita, Y Mukherjee, A Muller, T Munar, A Murat, P Murgia, S Musy, M Nakada, H Nakaya, T Nakano, I Nelson, C Neuberger, D Newman-Holmes, C Ngan, CYP Niu, H Nodulman, L Nomerotski, A Oh, SH Ohmoto, T Ohsugi, T Oishi, R Okabe, M Okusawa, T Olsen, J Pagliarone, C Paoletti, R Papadimitriou, V Pappas, SP Parashar, N Parri, A Partos, D Patrick, J Pauletta, G Paulini, M Perazzo, A Pescara, L Peters, MD Phillips, TJ Piacentino, G Pillai, M Pitts, KT Plunkett, R Pompos, A Pondrom, L Proudfoot, J Ptohos, F Punzi, G Ragan, K Reher, D Reischl, M Ribon, A Rimondi, F Ristori, L Robertson, WJ Robinson, A Rodrigo, R Rolli, S Rosenson, L Roser, R Saab, T Sakumoto, WK Saltzberg, D Sansoni, A Santi, L Sato, H Schlabach, P Schmidt, EE Schmidt, MP Scott, A Scribano, A Segler, S Seidel, S Seiya, Y Semeria, F Shah, T Shapiro, MD Shaw, NM Shepard, PF Shibayama, T Shimojima, M Shochet, M Siegrist, J Sill, A Sinervo, P Singh, P Sliwa, K Smith, C Snider, FD Spalding, J Speer, T Sphicas, P Spinella, F Spiropulu, M Spiegel, L Stanco, L Steele, J Stefanini, A Strohmer, R Strologas, J Strumia, F Stuart, D Sumorok, K Suzuki, J Suzuki, T Takahashi, T Takano, T Takashima, R Takikawa, K Tanaka, M Tannenbaum, B Tartarelli, F Taylor, W Tecchio, M Teng, PK Teramoto, Y Terashi, K Tether, S Theriot, D Thomas, TL Thurman-Keup, R Timko, M Tipton, P Titov, A Tkaczyk, S Toback, D Tollefson, K Tollestrup, A Toyoda, H Trischuk, W de Troconiz, JF Truitt, S Tseng, J Turini, N Uchida, T Ukegawa, F Valls, J van den Brink, SC Vejcik, S Velev, G Volobouev, I Vidal, R Vilar, R Vucinic, D Wagner, RG Wagner, RL Wahl, J Wallace, NB Walsh, AM Wang, C Wang, CH Wang, MJ Warburton, A Watanabe, T Watts, T Webb, R Wei, C Wenzel, H Wester, WC Wicklund, AB Wicklund, E Wilkinson, R Williams, HH Wilson, P Winer, BL Winn, D Wolinski, D Wolinski, J Worm, S Wu, X Wyss, J Yagil, A Yao, W Yasuoka, K Yeh, GP Yeh, P Yoh, J Yosef, C Yoshida, T Yu, I Zanetti, A Zetti, F Zucchelli, S AF Abe, F Akimoto, H Akopian, A Albrow, MG Amadon, A Amendolia, SR Amidei, D Antos, J Aota, S Apollinari, G Arisawa, T Asakawa, T Ashmanskas, W Atac, M Azzi-Bacchetta, P Bacchetta, N Bagdasarov, S Bailey, MW de Barbaro, P Barbaro-Galtieri, A Barnes, VE Barnett, BA Barone, M Bauer, G Baumann, T Bedeschi, F Behrends, S Belforte, S Bellettini, G Bellinger, J Benjamin, D Bensinger, J Beretvas, A Berge, JP Berryhill, J Bertolucci, S Bettelli, S Bevensee, B Bhatti, A Biery, K Bigongiari, C Binkley, M Bisello, D Blair, RE Blocker, C Bloom, K Busk, S Bodek, A Bokhari, W Bolla, G Bonushkin, Y Bortoletto, D Boudreau, J Brandl, A Breccia, L Bromberg, C Bruner, N Brunetti, R Buckley-Geer, E Budd, HS Burkett, K Busetto, G Byon-Wagner, A Byrum, KL Campbell, M Caner, A Carithers, W Carlsmith, D Cassada, J Castro, A Cauz, D Ceni, A Cerri, A Chang, PS Chang, PT Chao, HY Chapman, J Cheng, MT Chertok, M Chiarelli, G Chiou, CN Chlebana, F Christofek, L Cropp, R Chu, ML Cihangir, S Clark, AG Cobal, M Cocca, E Contreras, M Conway, J Cooper, J Cordelli, M Costanzo, D Couyoumtzelis, C Cronin-Hennessy, D Culbertson, R Dagenhart, D Daniels, T DeJongh, F Dell'Agnello, S Dell'Orso, M Demina, R Demortier, L Deninno, M Derwent, PF Devlin, T Dittmann, JR Donati, S Done, J Dorigo, T Eddy, N Einsweiler, K Elias, JE Ely, R Engels, E Erdmann, W Errede, D Errede, S Fan, Q Feild, RG Feng, Z Ferretti, C Fiori, I Flaugher, B Foster, GW Franklin, M Freeman, J Friedman, J Fukui, Y Gadomski, S Galeotti, S Gallinaro, M Ganel, O Garcia-Sciveres, M Garfinkel, AF Gay, C Geer, S Gerdes, DW Giannetti, P Giokaris, N Giromini, P Giusti, G Gold, M Gordon, A Goshaw, AT Gotra, Y Goulianos, K Grassmann, H Green, C Groer, L Grosso-Pilcher, C Guillian, G da Costa, JG Guo, RS Haber, C Hafen, E Hahn, SR Hamilton, R Handa, T Handler, R Hao, W Happacher, F Hara, K Hardman, AD Harris, RM Hartmann, F Hauser, J Hayashi, E Heinrich, J Heiss, A Hinrichsen, B Hoffman, KD Holck, C Hollebeek, R Holloway, L Huang, Z Huffman, BT Hughes, R Huston, J Huth, J Ikeda, H Incagli, M Incandela, J Introzzi, G Iwai, J Iwata, Y James, E Jensen, H Joshi, U Kajfasz, E Kambara, H Kamon, T Kaneko, T Karr, K Kasha, H Kato, Y Keaffaber, TA Kelley, K Kennedy, RD Kephart, R Kestenbaum, D Khazins, D Kikuchi, T Kirk, M Kim, BJ Kim, HS Kim, SH Kim, YK Kirsch, L Klimenko, S Knoblauch, D Koehn, P Kongeter, A Kondo, K Konigsberg, J Kordas, K Korytov, A Kovacs, E Kowald, W Kroll, J Kruse, M Kuhlmann, SE Kuns, E Kurino, K Kuwabara, T Laasanen, AT Lami, S Lammel, S Lamoureux, JI Lancaster, M Lanzoni, M Latino, G LeCompte, T Leone, S Lewis, JD Lindgren, M Liss, TM Liu, JB Liu, YC Lockyer, N Long, O Loreti, M Lucchesi, D Lukens, P Lusin, S Lys, J Maeshima, K Maksimovic, P Mangano, M Mariotti, M Marriner, JP Martignon, G Martin, A Matthews, JAJ Mazzanti, P McFarland, K McIntyre, P Melese, P Menguzzato, M Menzione, A Meschi, E Metzler, S Miao, C Miao, T Michail, G Miller, R Minato, H Miscetti, S Mishina, M Miyashita, S Moggi, N Moore, E Morita, Y Mukherjee, A Muller, T Munar, A Murat, P Murgia, S Musy, M Nakada, H Nakaya, T Nakano, I Nelson, C Neuberger, D Newman-Holmes, C Ngan, CYP Niu, H Nodulman, L Nomerotski, A Oh, SH Ohmoto, T Ohsugi, T Oishi, R Okabe, M Okusawa, T Olsen, J Pagliarone, C Paoletti, R Papadimitriou, V Pappas, SP Parashar, N Parri, A Partos, D Patrick, J Pauletta, G Paulini, M Perazzo, A Pescara, L Peters, MD Phillips, TJ Piacentino, G Pillai, M Pitts, KT Plunkett, R Pompos, A Pondrom, L Proudfoot, J Ptohos, F Punzi, G Ragan, K Reher, D Reischl, M Ribon, A Rimondi, F Ristori, L Robertson, WJ Robinson, A Rodrigo, R Rolli, S Rosenson, L Roser, R Saab, T Sakumoto, WK Saltzberg, D Sansoni, A Santi, L Sato, H Schlabach, P Schmidt, EE Schmidt, MP Scott, A Scribano, A Segler, S Seidel, S Seiya, Y Semeria, F Shah, T Shapiro, MD Shaw, NM Shepard, PF Shibayama, T Shimojima, M Shochet, M Siegrist, J Sill, A Sinervo, P Singh, P Sliwa, K Smith, C Snider, FD Spalding, J Speer, T Sphicas, P Spinella, F Spiropulu, M Spiegel, L Stanco, L Steele, J Stefanini, A Strohmer, R Strologas, J Strumia, F Stuart, D Sumorok, K Suzuki, J Suzuki, T Takahashi, T Takano, T Takashima, R Takikawa, K Tanaka, M Tannenbaum, B Tartarelli, F Taylor, W Tecchio, M Teng, PK Teramoto, Y Terashi, K Tether, S Theriot, D Thomas, TL Thurman-Keup, R Timko, M Tipton, P Titov, A Tkaczyk, S Toback, D Tollefson, K Tollestrup, A Toyoda, H Trischuk, W de Troconiz, JF Truitt, S Tseng, J Turini, N Uchida, T Ukegawa, F Valls, J van den Brink, SC Vejcik, S Velev, G Volobouev, I Vidal, R Vilar, R Vucinic, D Wagner, RG Wagner, RL Wahl, J Wallace, NB Walsh, AM Wang, C Wang, CH Wang, MJ Warburton, A Watanabe, T Watts, T Webb, R Wei, C Wenzel, H Wester, WC Wicklund, AB Wicklund, E Wilkinson, R Williams, HH Wilson, P Winer, BL Winn, D Wolinski, D Wolinski, J Worm, S Wu, X Wyss, J Yagil, A Yao, W Yasuoka, K Yeh, GP Yeh, P Yoh, J Yosef, C Yoshida, T Yu, I Zanetti, A Zetti, F Zucchelli, S TI Search for B-s(0)-(B)over-bar(s)(0) oscillations using the semileptonic decay B-s(0)->phi l(+)X nu SO PHYSICAL REVIEW LETTERS LA English DT Article ID B-0(B)OVER-BAR(0) AB A search for B-s(0)-(B) over bar(s)(0) oscillations is performed in a sample of B-s(0) semileptonic decays collected using dilepton triggers at the Tevatron Collider during 1992-1995. The B-s(0) is reconstructed using phi mesonlepton correlations; its initial production flavor is determined with the second lepton in the event. From a signal of 1068 with a B-s(0) purity of 61%, we obtain a limit on the B-s(0)-(B) over bar(s)(0) oscillation frequency of Delta m(s) > 5.8 ps(-1) at 95% confidence level. [S0031-9007 (99)09005-5]. C1 Kek Nat Lab High Energy Phys, Tsukuba, Ibaraki 305, Japan. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Bologna, Ist Nazl Fis Nucl, I-40127 Bologna, Italy. Brandeis Univ, Waltham, MA 02254 USA. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. Univ Chicago, Chicago, IL 60637 USA. Duke Univ, Durham, NC 27708 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Florida, Gainesville, FL 32611 USA. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Univ Geneva, CH-1211 Geneva 4, Switzerland. Harvard Univ, Cambridge, MA 02138 USA. Univ Illinois, Urbana, IL 61801 USA. Hiroshima Univ, Higashihiroshima 724, Japan. McGill Univ, Inst Particle Phys, Montreal, PQ H3A 2T8, Canada. Univ Toronto, Toronto, ON M5S 1A7, Canada. Johns Hopkins Univ, Baltimore, MD 21218 USA. Univ Karlsruhe, Inst Expt Kernphys, D-76128 Karlsruhe, Germany. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. MIT, Cambridge, MA 02139 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Michigan State Univ, E Lansing, MI 48824 USA. Univ New Mexico, Albuquerque, NM 87131 USA. Ohio State Univ, Columbus, OH 43210 USA. Osaka City Univ, Osaka 588, Japan. Univ Padua, Ist Nazl Fis Nucl, Sez Padova, I-35131 Padua, Italy. Univ Penn, Philadelphia, PA 19104 USA. Univ Pisa, Ist Nazl Fis Nucl, I-56100 Pisa, Italy. Scuola Normale Super Pisa, I-56100 Pisa, Italy. Univ Pittsburgh, Pittsburgh, PA 15260 USA. Purdue Univ, W Lafayette, IN 47907 USA. Univ Rochester, Rochester, NY 14627 USA. Rockefeller Univ, New York, NY 10021 USA. Rutgers State Univ, Piscataway, NJ 08855 USA. Acad Sinica, Taipei 11530, Taiwan. Texas A&M Univ, College Stn, TX 77843 USA. Texas Tech Univ, Lubbock, TX 79409 USA. Univ Trieste, Ist Nazl Fis Nucl, Udine, Italy. Univ Tsukuba, Tsukuba, Ibaraki 305, Japan. Tufts Univ, Medford, MA 02155 USA. Waseda Univ, Tokyo 169, Japan. Univ Wisconsin, Madison, WI 53706 USA. Yale Univ, New Haven, CT 06520 USA. RP Abe, F (reprint author), Kek Nat Lab High Energy Phys, Tsukuba, Ibaraki 305, Japan. RI Lancaster, Mark/C-1693-2008; Vucinic, Dejan/C-2406-2008; Nomerotski, Andrei/A-5169-2010; Azzi, Patrizia/H-5404-2012; Punzi, Giovanni/J-4947-2012; Chiarelli, Giorgio/E-8953-2012; Warburton, Andreas/N-8028-2013; Paulini, Manfred/N-7794-2014; Introzzi, Gianluca/K-2497-2015 OI Azzi, Patrizia/0000-0002-3129-828X; Punzi, Giovanni/0000-0002-8346-9052; Chiarelli, Giorgio/0000-0001-9851-4816; Warburton, Andreas/0000-0002-2298-7315; Paulini, Manfred/0000-0002-6714-5787; Introzzi, Gianluca/0000-0002-1314-2580 NR 8 TC 27 Z9 27 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 3 PY 1999 VL 82 IS 18 BP 3576 EP 3580 DI 10.1103/PhysRevLett.82.3576 PG 5 WC Physics, Multidisciplinary SC Physics GA 191UW UT WOS:000080040800004 ER PT J AU Lumpkin, AH Yang, BXX AF Lumpkin, AH Yang, BXX TI Use of few-angstrom radiation imaging to characterize ultrabright, multi-GeV particle beams SO PHYSICAL REVIEW LETTERS LA English DT Article ID STREAK-CAMERA; UNDULATOR RADIATION; RAY; DIFFRACTION; FELS; ESRF; VUV AB We have used the 7-GeV stored positron beam at the Advanced Photon Source to approximate relevant particle beam parameters of a diffraction-limited x-ray source and to perform measurements of few- to sub-angstrom radiation. Results are based on the 198-period diagnostics undulator optimized for low-divergence radiation cones (similar to 2.6 mu rad) at lambda similar to 0.5 Angstrom on the fundamental and on a unique synchroscan and dual-sweep x-ray streak camera (with a few picosecond resolution) that was phase locked to the accelerator's master oscillator subharmonic. Scaling of these techniques to future sources is presented. [S0031-9007(99)08983-8]. C1 Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RP Lumpkin, AH (reprint author), Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. NR 23 TC 1 Z9 1 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 3 PY 1999 VL 82 IS 18 BP 3605 EP 3608 DI 10.1103/PhysRevLett.82.3605 PG 4 WC Physics, Multidisciplinary SC Physics GA 191UW UT WOS:000080040800011 ER PT J AU Labaune, C Baldis, HA Bauer, BS Schifano, E Cohen, BI AF Labaune, C Baldis, HA Bauer, BS Schifano, E Cohen, BI TI Spatial and temporal coexistence of stimulated scattering processes under crossed-laser-beam irradiation SO PHYSICAL REVIEW LETTERS LA English DT Article ID BRILLOUIN-SCATTERING; RAMAN-SCATTERING; ENERGY-TRANSFER; PLASMA; INSTABILITIES; FLUCTUATIONS; COMPETITION; SUPPRESSION AB Spatial and temporal coexistence of ion-acoustic waves (IAW) and electron-plasma waves (EPW), driven, respectively, by stimulated Brillouin and Raman scattering, at significant levels of amplitude, has been observed under the modified conditions of a laser-plasma interaction. The results were obtained using a secondary interaction beam to modify the growth of the instabilities and the multiplexing technique of a streak camera to simultaneously record the temporal and spatial evolution of Thomson-scattered light from both the IAW and the EPW. [S0031-9007(99)09050-X]. C1 Ecole Polytech, CNRS, Lab Utilisat Lasers Intenses, F-91128 Palaiseau, France. Univ Calif Lawrence Livermore Natl Lab, Inst Laser Sci & Applicat, Livermore, CA 94550 USA. RP Labaune, C (reprint author), Ecole Polytech, CNRS, Lab Utilisat Lasers Intenses, F-91128 Palaiseau, France. NR 17 TC 8 Z9 8 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 3 PY 1999 VL 82 IS 18 BP 3613 EP 3616 DI 10.1103/PhysRevLett.82.3613 PG 4 WC Physics, Multidisciplinary SC Physics GA 191UW UT WOS:000080040800013 ER PT J AU Pedrosa, MA Hidalgo, C Carreras, BA Balbin, R Garcia-Cortes, I Newman, D van Milligen, B Sanchez, E Bleuel, J Endler, M Davies, S Matthews, GF AF Pedrosa, MA Hidalgo, C Carreras, BA Balbin, R Garcia-Cortes, I Newman, D van Milligen, B Sanchez, E Bleuel, J Endler, M Davies, S Matthews, GF TI Empirical similarity of frequency spectra of the edge-plasma fluctuations in toroidal magnetic-confinement systems SO PHYSICAL REVIEW LETTERS LA English DT Article ID SELF-ORGANIZED CRITICALITY; TURBULENT TRANSPORT; DYNAMICS; NOISE AB Frequency spectra of fluctuations of the ion saturation current, floating potential, and turbulent transport measured in the plasma edge of different fusion devices (tokamaks and stellarators) have been compared. All of the spectra show the same behavior over the whole frequency range investigated, which supports universality of plasma turbulence or turbulent transport. The results obtained are an indication of edge-plasma turbulence evolving into a critical state, independent of the size and plasma characteristics of the device. [S0031 -9007(99)09024-9]. C1 Asociac EURATOM, CIEMAT, Madrid 28040, Spain. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Max Planck Inst Plasmaphys, EURATOM Assoc, D-85740 Garching, Germany. Jet Joint Undertaking, Abingdon OX14 3EA, Oxon, England. RP Pedrosa, MA (reprint author), Asociac EURATOM, CIEMAT, Madrid 28040, Spain. RI Sanchez, Edilberto/D-4620-2009; van Milligen, Boudewijn/H-5121-2015; Garcia-Cortes, Isabel/H-3341-2015; Balbin, Rosa/F-8210-2010; Hidalgo, Carlos/H-6109-2015 OI Sanchez, Edilberto/0000-0003-1062-7870; van Milligen, Boudewijn/0000-0001-5344-6274; Garcia-Cortes, Isabel/0000-0002-5223-391X; Balbin, Rosa/0000-0001-5231-1300; NR 19 TC 70 Z9 70 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 3 PY 1999 VL 82 IS 18 BP 3621 EP 3624 DI 10.1103/PhysRevLett.82.3621 PG 4 WC Physics, Multidisciplinary SC Physics GA 191UW UT WOS:000080040800015 ER PT J AU Goodrich, RG Harrison, N Teklu, A Young, D Fisk, Z AF Goodrich, RG Harrison, N Teklu, A Young, D Fisk, Z TI Development of the high-field heavy-fermion ground state in CexLa1-xB6 intermetallics SO PHYSICAL REVIEW LETTERS LA English DT Article ID CYCLOTRON MASS; QUANTUM INTERFERENCE; ANDERSON LATTICE; MAGNETIC-FIELDS; CEB6; SURFACE; SYSTEMS; ALLOYS; LAB6 AB de Haas-van Alphen measurements in CexLa1-xB6 intermetallics reveal the existence of long-lived quasiparticles for all 0 < x < 1. This is accompanied by the enhancement of the field-dependent effective mass, together with changes to the topology of the Fermi surface developing very early in the series, and with the effective mass eventually exhibiting a maximum near x similar to 0.9. One of the spin contributions to the signal is also observed to disappear at very low x, indicating a spin polarity dependent scattering mechanism. [S0031-9007(99)09074-2]. C1 Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA. Univ Calif Los Alamos Natl Lab, Natl High Magnet Field Lab, Los Alamos, NM 87545 USA. Florida State Univ, Natl High Magnet Field Lab, Tallahassee, FL 32310 USA. RP Goodrich, RG (reprint author), Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA. NR 22 TC 43 Z9 43 U1 0 U2 7 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 3 PY 1999 VL 82 IS 18 BP 3669 EP 3672 DI 10.1103/PhysRevLett.82.3669 PG 4 WC Physics, Multidisciplinary SC Physics GA 191UW UT WOS:000080040800027 ER PT J AU Partee, J Frankevich, EL Uhlhorn, B Shinar, J Ding, Y Barton, TJ AF Partee, J Frankevich, EL Uhlhorn, B Shinar, J Ding, Y Barton, TJ TI Delayed fluorescence and triplet-triplet annihilation in pi-conjugated polymers SO PHYSICAL REVIEW LETTERS LA English DT Article ID DETECTED MAGNETIC-RESONANCE; LIGHT-EMITTING-DIODES; PHOTOEXCITED STATES; POLY(PARA-PHENYLENE VINYLENE); OPTICAL SPECTROSCOPY; EXCITON DYNAMICS; POLARON PAIRS; PHOTOLUMINESCENCE; POLY(PARAPHENYLENEVINYLENE) AB The delayed fluorescence of poly(p-phenylene vinylene) (PPV) and poly(p-phenylene ethynylene) (PPE) derivative solids and frozen solutions at 20 K is described. It provides strong evidence for triplet-triplet annihilation to singlets excitons, accounting for up to similar to 3% of the total emission in PPV films and similar to 1.5% in PPE powder. It also yields triplet lifetimes of 70 and 110 mu s in PPV films and frozen solutions, and similar to 200 and similar to 500 mu s in PPE powder and frozen solutions, respectively. [S0031-9007(99)09010-9]. C1 Iowa State Univ Sci & Technol, Ames Lab, US DOE, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames, IA 50011 USA. Iowa State Univ, Int Inst Theoret & Appl Phys, Ames, IA 50011 USA. Inst Energy Problems Chem Phys, Moscow 334, Russia. Iowa State Univ Sci & Technol, Dept Chem, Ames, IA 50011 USA. RP Iowa State Univ Sci & Technol, Ames Lab, US DOE, Ames, IA 50011 USA. NR 31 TC 87 Z9 88 U1 5 U2 30 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 3 PY 1999 VL 82 IS 18 BP 3673 EP 3676 DI 10.1103/PhysRevLett.82.3673 PG 4 WC Physics, Multidisciplinary SC Physics GA 191UW UT WOS:000080040800028 ER PT J AU Kozhevnikov, M Narayanamurti, V Zheng, C Chiu, YJ Smith, DL AF Kozhevnikov, M Narayanamurti, V Zheng, C Chiu, YJ Smith, DL TI Effect of electron scattering on second derivative ballistic electron emission spectroscopy in Au/GaAs/AlGaAs heterostructures SO PHYSICAL REVIEW LETTERS LA English DT Article ID BURIED SEMICONDUCTOR HETEROSTRUCTURES; BAND-STRUCTURE; MICROSCOPY; INTERFACES; TRANSPORT AB We present a quantitative study of the second voltage derivative (SD) of ballistic electron emission spectra of Au/GaAs/AlGaAs heterostructures to probe the effect of electron scattering on these spectra. Our analysis of the SD spectra shows that strong electron scattering occurs at the nonepitaxial Au/GaAs interface, leading to an experimentally observed redistribution of current among the electron transport channels. We also show that the effects of hot-electron scattering inside the semiconductor modify the spectra and are sensitive to the heterojunction band structure, its geometry, and temperature. [S0031-9007(99)09041-9]. C1 Univ Calif Santa Barbara, Dept Elect & Comp Engn, Santa Barbara, CA 93106 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Kozhevnikov, M (reprint author), Univ Calif Santa Barbara, Dept Elect & Comp Engn, Santa Barbara, CA 93106 USA. NR 18 TC 20 Z9 20 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 3 PY 1999 VL 82 IS 18 BP 3677 EP 3680 DI 10.1103/PhysRevLett.82.3677 PG 4 WC Physics, Multidisciplinary SC Physics GA 191UW UT WOS:000080040800029 ER PT J AU Tsouris, C Amarnath, KR Fedkiew, P AF Tsouris, C Amarnath, KR Fedkiew, P TI Electrochemical and reactive separations - Guest editors' note SO SEPARATION AND PURIFICATION TECHNOLOGY LA English DT Editorial Material C1 Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. Elect Power Res Inst, Palo Alto, CA USA. N Carolina State Univ, Dept Chem, Raleigh, NC 27695 USA. RP Tsouris, C (reprint author), Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. RI Tsouris, Costas/C-2544-2016 OI Tsouris, Costas/0000-0002-0522-1027 NR 5 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1383-5866 J9 SEP PURIF TECHNOL JI Sep. Purif. Technol. PD MAY 3 PY 1999 VL 15 IS 3 BP 193 EP 196 PG 4 WC Engineering, Chemical SC Engineering GA 187ZX UT WOS:000079820000001 ER PT J AU Slater, SA Raraz, AG Willit, JL Gay, EC AF Slater, SA Raraz, AG Willit, JL Gay, EC TI Electrochemical separation of aluminum from uranium for research reactor spent nuclear fuel applications SO SEPARATION AND PURIFICATION TECHNOLOGY LA English DT Article DE aluminum-based spent nuclear fuel; electrochemical separation; fluoride salt electrolyte; high throughput electrorefiner; uranium AB Researchers at Argonne National Laboratory (ANL) are developing an electrorefining process to treat aluminum-based spent nuclear fuel by electrochemically separating aluminum from uranium. The aluminum electrorefiner is modeled after the high-throughput electrorefiner developed at ANL. Aluminum is electrorefined, using a fluoride salt electrolyte, in a potential range of -0.1 V to -0.2 V, while uranium is electrorefined in a potential range of -0.3 V to -0.4 V; therefore, aluminum can be selectively separated electrochemically from uranium. A series of laboratory-scale experiments was performed to demonstrate the aluminum electrorefining concept. These experiments involved selecting an electrolyte (determining a suitable fluoride salt composition); selecting a crucible material for the electrochemical cell; optimizing the operating conditions; determining the effect of adding alkaline and rare earth elements to the electrolyte; and demonstrating the electrochemical separation of aluminum from uranium, using a U-Al-Si alloy as a simulant for aluminum-based spent nuclear fuel. Results of the laboratory-scale experiments indicate that aluminum can be selectively electrotransported from the anode to the cathode, while uranium remains in the anode basket. (C) 1999 Published by Elsevier Science B.V. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Slater, SA (reprint author), Argonne Natl Lab, 9700 S Cass Ave,Bldg 205, Argonne, IL 60439 USA. NR 6 TC 4 Z9 4 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1383-5866 J9 SEP PURIF TECHNOL JI Sep. Purif. Technol. PD MAY 3 PY 1999 VL 15 IS 3 BP 197 EP 205 DI 10.1016/S1383-5866(98)00101-4 PG 9 WC Engineering, Chemical SC Engineering GA 187ZX UT WOS:000079820000002 ER PT J AU Rassat, SD Sukamto, JH Orth, RJ Lilga, MA Hallen, RT AF Rassat, SD Sukamto, JH Orth, RJ Lilga, MA Hallen, RT TI Development of an electrically switched ion exchange process for selective ion separations SO SEPARATION AND PURIFICATION TECHNOLOGY LA English DT Article DE alkali cations; electroactive materials; electrochemical separation; ion exchange; pulp process stream; radioactive wastes ID CHEMICALLY DERIVATIZED INTERFACE; NICKEL ELECTRODE; CHARGE-TRANSFER; FILMS; HEXACYANOFERRATE; SURFACES; RECOVERY; CYCLE; CHLORIDE; REMOVAL AB The electrically switched ion exchange (ESIX) process, being developed at Pacific Northwest National Laboratory, provides an alternative separation method to selectively remove ions from process and waste streams. In the ESIX process, in which an electroactive ion exchange him is deposited onto a high surface area elecrotrode, uptake and elution are controlled directly by modulating the electrochemical potential of the film. This paper addresses engineering issues necessary to fully develop ESIX for specific industrial alkali cation separation challenges. The cycling and chemical stability and alkali cation selectivity of nickel hexacyanoferrate (NiHCF) electroactive films were investigated. The selectivity of NiHCF was determined using cyclic voltammetry and a quartz crystal microbalance to quantify ion uptake in the film. Separation factors indicated a high selectivity for cesium and a moderate selectivity for potassium in high sodium content solutions. A NiHCF film with improved redox cycling and chemical stability in a simulated pulp mill process stream, a targeted application for ESIX, was also prepared and tested. (C) 1999 Published by Elsevier Science B.V. C1 Pacific NW Lab, Richland, WA 99352 USA. RP Rassat, SD (reprint author), Pacific NW Lab, POB 999, Richland, WA 99352 USA. NR 35 TC 53 Z9 65 U1 2 U2 14 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1383-5866 J9 SEP PURIF TECHNOL JI Sep. Purif. Technol. PD MAY 3 PY 1999 VL 15 IS 3 BP 207 EP 222 DI 10.1016/S1383-5866(98)00102-6 PG 16 WC Engineering, Chemical SC Engineering GA 187ZX UT WOS:000079820000003 ER PT J AU Hobbs, DT AF Hobbs, DT TI Caustic recovery from alkaline nuclear waste by an electrochemical separation process SO SEPARATION AND PURIFICATION TECHNOLOGY LA English DT Article DE alkaline; ceramic; electrochemistry; membrane; organic ID HYDROXIDE AB Large quantities of highly-alkaline, radioactive liquid wastes are stored in underground tanks at the Department of Energy's Savannah River, Hanford and Oak Ridge sites. These wastes will be pre-treated to separate radionuclides and the remaining decontaminated liquid wastes will be incorporated into solid wasteforms for permanent disposal. Significant savings in disposal costs could result by recovering the sodium hydroxide for re-use. Laboratory tests demonstrated an electrochemical separation process for the recovery of sodium hydroxide from simulated and radioactive Savannah River Site (SRS) wastes. The separation process uses an electrochemical cell separated into two compartments with a cation-selective membrane. The waste solution enters the anolyte side of the cell. Sodium ions migrate across the membrane into the catholyte. Hydroxide forms at the cathode by the reduction of water. The catholyte product is thus sodium hydroxide or caustic. Hydroxide oxidizes at the anode to form oxygen and water. The anolyte product is thus a sodium hydroxide-depleted waste stream. If nitrite is present in the waste solution, the nitrite also oxidizes to nitrate. Two different membranes were evaluated: an organic-based membrane, Nafion(R) Type 324 or 350, and an inorganic-based membrane, Ceramatec(R) NASD. Initial tests with the Nafion(R) membrane with simulated waste solutions indicated that the migration of sodium across the membrane was not significantly affected by changes in the current density, temperature and the concentrations of nitrate/nitrite, hydroxide and aluminate. Both membranes successfully separated caustic from radioactive SRS waste. (C) 1999 Westinghouse Savannah River Company. Published by Elsevier Science Ltd. All rights reserved. C1 Westinghouse Savannah River Co, Savannah River Technol Ctr, Aiken, SC 29808 USA. RP Hobbs, DT (reprint author), Westinghouse Savannah River Co, Savannah River Technol Ctr, Aiken, SC 29808 USA. NR 11 TC 14 Z9 14 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1383-5866 J9 SEP PURIF TECHNOL JI Sep. Purif. Technol. PD MAY 3 PY 1999 VL 15 IS 3 BP 239 EP 253 DI 10.1016/S1383-5866(98)00105-1 PG 15 WC Engineering, Chemical SC Engineering GA 187ZX UT WOS:000079820000006 ER PT J AU Shin, WT Mirmiran, A Yiacoumi, S Tsouris, C AF Shin, WT Mirmiran, A Yiacoumi, S Tsouris, C TI Ozonation using microbubbles formed by electric fields SO SEPARATION AND PURIFICATION TECHNOLOGY LA English DT Article DE bubble column; electrostatic spraying; microbubbles; ozonation ID ELECTROSTATIC DISPERSION; ORGANIC CONTAMINANTS; NONCONDUCTIVE FLUIDS; OZONE CONCENTRATION; CONDUCTIVE FLUIDS; AQUEOUS-SOLUTION; OXIDATION; WATER; WASTEWATERS; REACTORS AB The use of ozone in water and wastewater treatment systems has been shown to be a process that is limited by mass transfer. The most effective way to overcome this limitation is to increase the interfacial area available for mass transfer by decreasing the size of the ozone gas bubbles that are dispersed in solution. Electrostatic spraying (ES) of ozone into water was investigated in this work as a method of increasing the rate of mass transfer of ozone into a solution and thereby increasing the rate of phenol oxidation. The studies were conducted in a 30 cm column of 7.5 cm internal diameter, using deionized water and phenol as the solution phase and an ozone-oxygen mixture, generated by a corona-discharge ozone generator, as the gas phase. Results were obtained for ES at input power levels ranging from 0 to 4 kV and compared with two different pore-size bubble diffusers (10-15 mu m and 40-60 mu m). It was determined that the rate of mass transfer could be increased by as much as 40% when the applied voltage was increased from 0 to 4 kV as a result of the smaller bubbles generated by ES. In addition, ES was shown to be more effective than the medium-pore-size (10-15 mu m) bubble diffuser; the best results were achieved at low gas flow rates. Phenol oxidation rates were also compared for ES and the medium-port-size bubble diffuser, and the results indicate that the increased mass transfer rate achieved by ES enhances the rate of removal of phenol from solution. (C) 1999 Elsevier Science B.V. C1 Georgia Inst Technol, Sch Civil & Environm Engn, Atlanta, GA 30332 USA. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. RP Yiacoumi, S (reprint author), Georgia Inst Technol, Sch Civil & Environm Engn, Atlanta, GA 30332 USA. RI Tsouris, Costas/C-2544-2016 OI Tsouris, Costas/0000-0002-0522-1027 NR 36 TC 31 Z9 41 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1383-5866 J9 SEP PURIF TECHNOL JI Sep. Purif. Technol. PD MAY 3 PY 1999 VL 15 IS 3 BP 271 EP 282 DI 10.1016/S1383-5866(98)00107-5 PG 12 WC Engineering, Chemical SC Engineering GA 187ZX UT WOS:000079820000008 ER PT J AU Blankenship, KD DePaoli, DW Hylton, JO Tsouris, C AF Blankenship, KD DePaoli, DW Hylton, JO Tsouris, C TI Effect of electrode configurations on phase equilibria with applied electric fields SO SEPARATION AND PURIFICATION TECHNOLOGY LA English DT Article DE electric-field distillation; electrodistillation; vapor-liquid equilibria AB Applying an electric field to some boiling binary mixtures has been shown experimentally to increase the separation factor by as much as 10%. In this work, an electric field was applied across the interface of boiling mixtures of 2-propanol-water via electrodes located in the vapor and the liquid. The shape and separation of the electrodes and the strength and polarity of the electric field were altered to investigate their effect on the vapor mole fraction, the current, and the vapor temperature. The results show that greater voltage differences, in the absence of excessive electrical current, lead to higher concentrations of 2-propanol in the vapor. However. it was found that varying the electrode separation at a given potential difference, and thus the electric field strength, has little effect on the vapor composition. The effects of the applied potential difference are reduced with elevated current and under conditions where liquid dynamics such as dripping, splashing, or jetting provide an opportunity for charge to be transferred between the electrode in the vapor and the liquid. It is also shown that directing the electric field from the vapor to the liquid produces a lower current, and the effect on the composition is larger. These findings, in combination with calculations of the interface charge density, suggest that improvements in the separation efficiency achieved by an applied potential difference are not due to effects of the electric field in the bulk fluids, but rather are induced by charge accumulation at the vapor-liquid interface. (C) 1999 Elsevier Science B.V. C1 Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Instrumentat & Controls, Oak Ridge, TN 37831 USA. RP DePaoli, DW (reprint author), Oak Ridge Natl Lab, Div Chem Technol, POB 2008, Oak Ridge, TN 37831 USA. RI Tsouris, Costas/C-2544-2016 OI Tsouris, Costas/0000-0002-0522-1027 NR 15 TC 2 Z9 3 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1383-5866 J9 SEP PURIF TECHNOL JI Sep. Purif. Technol. PD MAY 3 PY 1999 VL 15 IS 3 BP 283 EP 294 DI 10.1016/S1383-5866(98)00108-7 PG 12 WC Engineering, Chemical SC Engineering GA 187ZX UT WOS:000079820000009 ER PT J AU Cotton, FA Daniels, LM Haefner, SC Sattelberger, AP AF Cotton, FA Daniels, LM Haefner, SC Sattelberger, AP TI Metal-metal multiply-bonded complexes of technetium. Part 8. Synthesis and characterization of the alpha- and beta-isomers of Tc2Cl4(dppe)(2) SO INORGANICA CHIMICA ACTA LA English DT Article DE crystal structures; technetium complexes; metal-metal bond complexes ID RHENIUM TRIPLE BOND; STRUCTURAL CHARACTERIZATION; STAGGERED CONFORMATION; CRYSTAL-STRUCTURE; DITECHNETIUM; RE2X4(LL)2 AB The alpha- (chelated) and beta- (bridged) isomers of Tc2Cl4(dppe)(2) (dppe = Ph2PCH2CH2PPh2) have been prepared and characterized. The reaction of Tc2Cl4(PEt3)(4) or Tc2Cl4(PMe2Ph)(4) with dppe in refluxing toluene affords the pale pink p-isomer, isostructural with both the analogous Mo and Re compounds. When Tc2Cl4(PMePh2)(4) is refluxed in toluene with a large excess of dppe, the mauve alpha-isomer is produced. Spectral and electrochemical properties as well as reactivity of each isomer are reported. For each the X-ray crystal structure is also reported. The alpha-isomer has average Tc-Tc = 2.15[1] Angstrom and an eclipsed conformation. For the beta-isomer there is a twict angle of 35(2)degrees and a Tc-Tc distance of 2.117(1) Angstrom. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Texas A&M Univ, Mol Struct & Bonding Lab, Dept Chem, College Stn, TX 77842 USA. Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Cotton, FA (reprint author), Texas A&M Univ, Mol Struct & Bonding Lab, Dept Chem, POB 30012, College Stn, TX 77842 USA. NR 22 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0020-1693 J9 INORG CHIM ACTA JI Inorg. Chim. Acta PD MAY 2 PY 1999 VL 288 IS 1 BP 69 EP 73 DI 10.1016/S0020-1693(99)00036-5 PG 5 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 201DE UT WOS:000080578900010 ER PT J AU Osipiuk, J Walsh, MA Freeman, BC Morimoto, RI Joachimiak, A AF Osipiuk, J Walsh, MA Freeman, BC Morimoto, RI Joachimiak, A TI Structure of a new crystal form of human Hsp70 ATPase domain SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article ID MOLECULAR CHAPERONE DNAK AB Hsp70 proteins are highly conserved proteins induced by heat shock and other stress conditions. An ATP-binding domain of human Hsp70 protein has been crystallized in two major morphological forms at pH 7.0 in the presence of PEG 8000 and CaCl2. Both crystal forms belong to the orthorhombic space group P2(1)2(1)2(1), but show no resemblance in unit-cell parameters. Analysis of the crystal structures for both forms shows a 1-2 Angstrom shift of one of the subdomains of the protein. This conformational change could reflect a 'natural' flexibility of the protein which might be relevant to ATP binding and may facilitate the interaction of other proteins with Hsp70 protein. C1 Argonne Natl Lab, Ctr Mech Biol & Biotechnol, Argonne, IL 60439 USA. Univ Gdansk, Dept Microbiol, PL-80822 Gdansk, Poland. Northwestern Univ, Dept Biochem Mol Biol & Cell Biol, Evanston, IL 60208 USA. RP Osipiuk, J (reprint author), Argonne Natl Lab, Ctr Mech Biol & Biotechnol, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Walsh, Martin/I-1566-2013 OI Walsh, Martin/0000-0001-5683-1151 NR 13 TC 33 Z9 36 U1 0 U2 2 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0907-4449 J9 ACTA CRYSTALLOGR D JI Acta Crystallogr. Sect. D-Biol. Crystallogr. PD MAY PY 1999 VL 55 BP 1105 EP 1107 DI 10.1107/S0907444999002103 PN 5 PG 3 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 198AN UT WOS:000080399700031 PM 10216320 ER PT J AU Gong, H Chen, S He, GW AF Gong, H Chen, S He, GW TI An analysis of subgrid-resolved scale interactions with use of results from direct numerical simulations SO ACTA MECHANICA SINICA LA English DT Article DE subgrid nonlinear interaction; energy transfer; large eddy simulation (LES); subgrid scale (SGS); direct numerical simulation; isotropic turbulence ID ISOTROPIC TURBULENCE; ENERGY-TRANSFER AB Subgrid nonlinear interaction and energy transfer are analyzed using direct numerical simulations of isotropic turbulence. Influences of cutoff wave number at different ranges of scale on the energetics and dynamics have been investigated. It is observed that subgrid-subgrid interaction dominates the turbulent dynamics when cut-off wave number locates in the energy-containing range while resolved-subgrid interaction dominates if it is in the dissipation range; By decomposing the subgrid energy transfer and nonlinear interaction into 'forward' and 'backward' groups according to the sign of triadic interaction, we find that individually each group has very large contribution, but the net of them is much smaller, implying that tremendous cancellation happens between these two groups. C1 Univ Calif Los Alamos Natl Lab, Environm Safety & Hlth Div, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. Chinese Acad Sci, Inst Mech, LNM, Beijing 100080, Peoples R China. RP Gong, H (reprint author), Univ Calif Los Alamos Natl Lab, Environm Safety & Hlth Div, POB 1663, Los Alamos, NM 87545 USA. RI Chen, Shiyi/A-3234-2010 NR 9 TC 3 Z9 3 U1 0 U2 0 PU CHINESE JOURNAL MECHANICS PRESS PI BEIJING PA 15 ZHONG-GUAN-CUN ST, BEIJING 100080, PEOPLES R CHINA SN 0567-7718 J9 ACTA MECH SINICA JI Acta Mech. Sin. PD MAY PY 1999 VL 15 IS 2 BP 108 EP 115 DI 10.1007/BF02485875 PG 8 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA 210MP UT WOS:000081109500002 ER PT J AU Mazonka, O Blocki, J Jarzynski, C AF Mazonka, O Blocki, J Jarzynski, C TI A new method of calculating very small cross sections SO ACTA PHYSICA POLONICA B LA English DT Article; Proceedings Paper CT International Conference on Nuclear Physics Close to the Barrier CY JUN 30-JUL 04, 1998 CL WARSAW, POLAND AB Langevin equations are used to model many processes of physical interest, including low-energy nuclear collisions. We develop a general method for computing probabilities of very rare events (e.g. small fusion cross-sections) for processes described by Langevin dynamics. As we demonstrate with numerical examples, our method can converge to the desired answer at a rate which is orders of magnitude faster than that achieved by using direct simulations of the process in question. C1 Inst Nucl Studies, Swierk, Poland. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Mazonka, O (reprint author), Inst Nucl Studies, Swierk, Poland. RI Jarzynski, Christopher/B-4490-2009 OI Jarzynski, Christopher/0000-0002-3464-2920 NR 6 TC 0 Z9 0 U1 0 U2 0 PU ACTA PHYSICA POLONICA B, JAGELLONIAN UNIV, INST PHYSICS PI KRAKOW PA REYMONTA 4, 30-059 KRAKOW, POLAND SN 0587-4254 J9 ACTA PHYS POL B JI Acta Phys. Pol. B PD MAY PY 1999 VL 30 IS 5 BP 1577 EP 1585 PG 9 WC Physics, Multidisciplinary SC Physics GA 212AN UT WOS:000081194200044 ER PT J AU Stephenson, DJ Fairchild, CI Buchan, RM Dakins, ME AF Stephenson, DJ Fairchild, CI Buchan, RM Dakins, ME TI A fiber characterization of the natural zeolite, mordenite: A potential inhalation health hazard SO AEROSOL SCIENCE AND TECHNOLOGY LA English DT Article ID ERIONITE; RATS AB Interest in mordenite as an inhalation hazard arose when it was discovered that the mineral exists in the subsurface of Yucca Mountain, NV, the site of a federally proposed nuclear waste repository, During preliminary geologic investigations at Yucca Mountain, workers performing air coring (dry-drilling) operations were potentially exposed to aerosols of mordenite, Mordenite is also increasingly used in industrial applications, such as cation exchange, molecular absorbency, and reversible dehydration, Concern that the fibrous nature of mordenite may present an inhalation hazard is supported by the "Stanton Hypothesis," which states that the carcinogenicity of any fiber type depends upon dimension and durability rather than physicochemical properties. To date, little scientific literature is available on the inhalation health hazards of mordenite, This study initiates research in this area, Mordenite specimens collected from different geologic localities were analyzed macroscopically and microscopically. Mineral verification was performed using energy dispersive x-ray and x-ray diffraction analysis. Fibrous aerosols were generated to simulate aerosols created during air coring operations. Anderson cascade impacters were used to obtain aerosol mass median aerodynamic diameters, Electron microscopy of nucleopore filters allowed for individual aerosol fibers to be morphologically sized and applied to the Stanton Hypothesis for mesothelioma induction, Physical fiber dimensions were used to calculate aerodynamic diameters and to estimate pulmonary deposition. Results obtained from this study indicate that under similar conditions of aerosolization, using similar mordenite materials, inhalation of mordenite fibers could produce substantial deep-lung deposition. C1 Univ Utah, Rocky Mt Ctr Occupat & Environm Hlth, Ind Hyg Program, Salt Lake City, UT 84112 USA. Univ Calif Los Alamos Natl Lab, Environm Safety & Hlth Div, Ind Hyd & Safety Grp, Res & Dev Sect, Los Alamos, NM 87545 USA. Colorado State Univ, Coll Vet Med & Biomed Sci, Dept Environm Hlth, Occupat Hlth & Safety Sect, Ft Collins, CO 80523 USA. Univ Idaho, Environm Sci Program, Idaho Falls, ID 83402 USA. RP Stephenson, DJ (reprint author), Univ Utah, Rocky Mt Ctr Occupat & Environm Hlth, Ind Hyg Program, 75 S 2000 E, Salt Lake City, UT 84112 USA. NR 14 TC 6 Z9 6 U1 2 U2 3 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA SN 0278-6826 J9 AEROSOL SCI TECH JI Aerosol Sci. Technol. PD MAY PY 1999 VL 30 IS 5 BP 467 EP 476 DI 10.1080/027868299304507 PG 10 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 196GZ UT WOS:000080301800007 ER PT J AU Scripsick, RC Beckman, RJ Mokler, BV Hinds, WC Martinez, VA AF Scripsick, RC Beckman, RJ Mokler, BV Hinds, WC Martinez, VA TI In-place filter testing geometry effects on test result uncertainty: Single stage systems SO AMERICAN INDUSTRIAL HYGIENE ASSOCIATION JOURNAL LA English DT Article DE air sampling; emissions monitoring; HEPA filter; in-place filter testing; nuclear air cleaning; performance assurance AB In-place filter testing is a widely accepted practice for assuring performance of high-efficiency particulate air (HEPA) filter systems. American Society of Mechanical Engineers (ASME) standards address aspects of uncertainty in in-place filter test results through limits on spatial variation of test aerosol concentration and flow velocity. This article augments the standards by developing an approximate expression for test result uncertainty, The expression uses concentration, flow velocity, and penetration heterogeneities as indices of spatial variation, The uncertainty expression is used to evaluate testing of a hypothetical HEPA filter system meeting requirements of the standards and of an operating field HEPA filter system. At a performance acceptance limit of 5 x 10(-4) penetration, uncertainty in tests on the standard system is just over the inferred ASME system acceptance limit of 6.7%. Uncertainty for field system tests is more than twice the limit. The uncertainty expression is used to determine limits on test results that assure compliance with system performance acceptance limits and to evaluate options for modifying the field system. The approach presented here provides a potential mechanism to economically establish a correspondence between tests on qualified nonstandard systems and requirements of the standards. The correspondence assures that tests on the nonstandard systems provide performance assurance equivalent to tests on fully compliant systems, Nonstandard systems that pass these tests can be reasonably expected to meet the same health and environmental protection requirements as fully compliant systems. C1 Univ Calif Los Alamos Natl Lab, Ind Hyg & Safety Grp, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Stat Grp, Los Alamos, NM 87545 USA. Environm Hlth Sci Inc, Albuquerque, NM 87110 USA. Univ Calif Los Angeles, Sch Publ Hlth, Dept Environm Hlth Sci, Los Angeles, CA 90024 USA. Univ Calif Los Alamos Natl Lab, Air Qual Grp, Los Alamos, NM 87545 USA. RP Scripsick, RC (reprint author), Univ Calif Los Alamos Natl Lab, Ind Hyg & Safety Grp, POB 1663, Los Alamos, NM 87545 USA. NR 33 TC 0 Z9 0 U1 0 U2 3 PU AMER INDUSTRIAL HYGIENE ASSOC PI FAIRFAX PA 2700 PROSPERITY AVE #250, FAIRFAX, VA 22031-4307 USA SN 0002-8894 J9 AM IND HYG ASSOC J JI Am. Ind. Hyg. Assoc. J. PD MAY-JUN PY 1999 VL 60 IS 3 BP 300 EP 309 PG 10 WC Environmental Sciences; Public, Environmental & Occupational Health SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health GA 206YT UT WOS:000080908700005 ER PT J AU Tittiranonda, P Rempel, D Armstrong, T Burastero, S AF Tittiranonda, P Rempel, D Armstrong, T Burastero, S TI Workplace use of an adjustable keyboard: Adjustment preferences and effect on wrist posture SO AMERICAN INDUSTRIAL HYGIENE ASSOCIATION JOURNAL LA English DT Article DE adjustable keyboard; musculoskeletal disorders; user preference; wrist motion ID CARPAL-TUNNEL SYNDROME; MUSCULOSKELETAL DISORDERS; WORK AB This study presents an evaluation of an adjustable keyboard based on subjective preference and wrist joint motion during typing, Thirty-five computer users used the adjustable split design keyboard for 7-14 days during their usual work and were instructed to adjust the keyboard to the opening angle they preferred. At the end of this period, three-dimensional motion analysis was performed to compare the distribution of wrist joint angles while subjects typed on a conventional keyboard and the adjustable keyboard adjusted to the subject's preferred angle. The mean preferred opening angle was 14 degrees +/- 10, The mean ulnar deviation of the subjects who selected the opening angles between 21 and 28 degrees (n = 12) decreased from 18 degrees +/- 5 on the flat to 14 degrees +/- 5 on the adjustable (p < 0.05), while those who selected 0 to 10 degrees (n = 6) and 11 to 20 degrees (n = 17) split angles showed no significant differences in ulnar deviation. Mean wrist extension on the adjustable keyboard was 17 degrees +/- 5 and was significantly less than the 24 degrees +/- 5 observed on the conventional keyboard and most likely due to the presence of palm support. On average, subjects reported that the adjustable keyboard was more comfortable (0.5 +/- 0.5) (worse = -1, same = 0, better, = 1) in comparison with the conventional keyboard. C1 Lawrence Livermore Natl Lab, Interdisciplinary Ergon Program, Livermore, CA 94550 USA. Univ Michigan, Ctr Ergon, Ann Arbor, MI 48109 USA. Univ Calif San Francisco, Div Environm & Occupat Med, Richmond, CA 94804 USA. RP Lawrence Livermore Natl Lab, Interdisciplinary Ergon Program, Mailstop L-723, Livermore, CA 94550 USA. RI Rempel, David/E-8424-2013 NR 27 TC 13 Z9 13 U1 0 U2 5 PU AMER INDUSTRIAL HYGIENE ASSOC PI FAIRFAX PA 2700 PROSPERITY AVE #250, FAIRFAX, VA 22031-4307 USA SN 0002-8894 J9 AM IND HYG ASSOC J JI Am. Ind. Hyg. Assoc. J. PD MAY-JUN PY 1999 VL 60 IS 3 BP 340 EP 348 PG 9 WC Environmental Sciences; Public, Environmental & Occupational Health SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health GA 206YT UT WOS:000080908700010 PM 10386355 ER PT J AU Jankovic, JT Underwood, WS Goodwin, GM AF Jankovic, JT Underwood, WS Goodwin, GM TI Exposures from thorium contained in thoriated tungsten welding electrodes SO AMERICAN INDUSTRIAL HYGIENE ASSOCIATION JOURNAL LA English DT Article DE radiation; thorium; welding AB information provided in this article can be used for estimating the radiation dose associated with the use of thoriated tungsten electrodes in tungsten inert gas welding. Area and breathing zone concentrations of Th-232 generated by welding and electrode sharpening along with particle size information; isotopic composition of electrodes from two domestic manufacturers and one European manufacturer; and process variables and estimates on the number of thoriated tungsten electrodes manufactured are presented. Past literature is reviewed and compared with the results of this study. Isotopic analysis of a nominal 2% thoriated electrode found 0.6 ppm +/- 0.4 ppm Th-230 and less than 0.1 ppm Th-288. Analysis of a ceriated tungsten electrode and a lanthanated tungsten electrode for Th-232 found 124 ppm and 177 ppm, respectively. Electrode consumption during welding was primarily the result of tip sharpening. Less than 3% of the weight loss was attributable to the welding process. The in-mask concentration of respirable thorium particulate in the welder's breathing zone was 0.002 x 10(-12) mu Ci Th-232/mL. Th, concentration of respirable thorium particulate from electrode sharpening was 1.3 x 10 (12) mu Ci Th-232/mL. The measured sharpening time was 20 sec per electrode. Estimates of the activity median aerodynamic diameters for the respirable fraction of the welding and electrode sharpening aerosols were 3.5 and 5 mu m, respectively, when measured in the breathing zone at 0.3 m (12 inches) from the point of operation, The respirable fraction of the total welding and sharpening aerosols was 45 and 60%. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Jankovic, JT (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA. NR 17 TC 8 Z9 8 U1 0 U2 2 PU AMER INDUSTRIAL HYGIENE ASSOC PI FAIRFAX PA 2700 PROSPERITY AVE #250, FAIRFAX, VA 22031-4307 USA SN 0002-8894 J9 AM IND HYG ASSOC J JI Am. Ind. Hyg. Assoc. J. PD MAY-JUN PY 1999 VL 60 IS 3 BP 384 EP 389 DI 10.1080/00028899908984457 PG 6 WC Environmental Sciences; Public, Environmental & Occupational Health SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health GA 206YT UT WOS:000080908700016 PM 10386359 ER PT J AU Tanabe, JL Ezekiel, F Jagust, WJ Reed, BR Norman, D Schuff, N Weiner, MW Chui, H Fein, G AF Tanabe, JL Ezekiel, F Jagust, WJ Reed, BR Norman, D Schuff, N Weiner, MW Chui, H Fein, G TI Magnetization transfer ratio of white matter hyperintensities in subcortical ischemic vascular dementia SO AMERICAN JOURNAL OF NEURORADIOLOGY LA English DT Article ID MULTIPLE-SCLEROSIS; DISEASE; LESIONS; LEUKOARAIOSIS; MR; ROTTERDAM; IMAGES; BRAIN AB BACKGROUND AND PURPOSE: In subjects with subcortical ischemic vascular dementia (SIVD), tissue vacuolization, myelin pallor, and demyelination have been found on pathologic examination of white matter signal hyperintensities (WMSH). Magnetization transfer ratio (MTR) values provide a potential measure of compromised white matter integrity. The purpose of this study was to determine if there were differences in MTR of WMSH between subjects with SIVD and cognitively normal healthy control subjects, METHODS: Fifteen subjects with SIVD and 16 control subjects of comparable age and sex were studied, MTR images were coregistered to MR images segmented into tissue classes (gray matter, white matter, CSF, WMSH, and lacunar infarcts), MTR of WMSH was compared across groups and examined by WMSH location, size, and total burden, RESULTS: WMSH burden was greater in SIVD patients than in control subjects (2.4% vs 0.67%), MTR of WMSH did not differ between groups, but MTR of periventricular WMSH was lower in SIVD patients than in control subjects (37.6% vs 39.4%). Even after accounting for covariant effects of lesion burden, there was still a trend toward reduced periventricular WMSH MTR in the group with dementia. There was no correlation between WMSH MTR and WMSH lesion size. CONCLUSION: These findings are consistent with observations that pathologic changes in vascular dementia are most severe in the periventricular white matter and suggest that insight into the pathophysiology of SIVD might be gleaned from studies of the periventricular region. C1 Dept Vet Affairs Med Ctr, Magnet Resonance Unit, San Francisco, CA 94121 USA. NYU Med Ctr, Dept Radiol, New York, NY 10016 USA. Univ Calif San Francisco, Dept Radiol, San Francisco, CA 94143 USA. Univ Calif San Francisco, Dept Psychiat, San Francisco, CA 94143 USA. Lawrence Berkeley Lab, Ctr Funct Imaging, Berkeley, CA USA. Univ Calif Davis, Dept Neurol, Davis, CA 95616 USA. Univ So Calif, Dept Neurol, Los Angeles, CA USA. RP Fein, G (reprint author), Dept Vet Affairs Med Ctr, Magnet Resonance Unit, 4150 Clement St, San Francisco, CA 94121 USA. FU NIA NIH HHS [P01 AG12535, AG 10129, P01 AG012435, P30 AG010129, R01 AG010897, U01 AG012535]; NIDA NIH HHS [DA-05683-02, F32 DA005683] NR 32 TC 40 Z9 40 U1 0 U2 1 PU AMER SOC NEURORADIOLOGY PI OAK BROOK PA 2210 MIDWEST RD, OAK BROOK, IL 60521 USA SN 0195-6108 J9 AM J NEURORADIOL JI Am. J. Neuroradiol. PD MAY PY 1999 VL 20 IS 5 BP 839 EP 844 PG 6 WC Clinical Neurology; Neuroimaging; Radiology, Nuclear Medicine & Medical Imaging SC Neurosciences & Neurology; Radiology, Nuclear Medicine & Medical Imaging GA 198RY UT WOS:000080439000018 PM 10369354 ER PT J AU Vorobieff, P Ecke, RE AF Vorobieff, P Ecke, RE TI Fluid instabilities and wakes in a soap-film tunnel SO AMERICAN JOURNAL OF PHYSICS LA English DT Article ID TURBULENCE; VELOCITY; LAMINAR; FLOWS AB We present a compact, low-budget two-dimensional hydrodynamic flow visualization system based on a tilted, gravity-driven soap film tunnel. This system is suitable for demonstrations and studies of a variety of fluid mechanics problems, including turbulent wakes past bluff bodies and lifting surfaces, Kelvin-Helmholtz instability, and grid turbulence. (C) 1999 American Association of Physics Teachers. C1 Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Condensed Matter & Thermal Phys Grp, Los Alamos, NM 87545 USA. RP Vorobieff, P (reprint author), Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. RI Vorobieff, Peter/B-3376-2011; OI Vorobieff, Peter/0000-0003-0631-7263; Ecke, Robert/0000-0001-7772-5876 NR 21 TC 6 Z9 9 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0002-9505 J9 AM J PHYS JI Am. J. Phys. PD MAY PY 1999 VL 67 IS 5 BP 394 EP 399 DI 10.1119/1.19274 PG 6 WC Education, Scientific Disciplines; Physics, Multidisciplinary SC Education & Educational Research; Physics GA 189RJ UT WOS:000079919300007 ER PT J AU Khanna, S Roy, S Packer, L Sen, CK AF Khanna, S Roy, S Packer, L Sen, CK TI Cytokine-induced glucose uptake in skeletal muscle: redox regulation and the role of alpha-lipoic acid SO AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY LA English DT Article DE antioxidant; immune system; infection; metabolism; nitric oxide; thioctic acid ID TUMOR-NECROSIS-FACTOR; TRANSPORTER MESSENGER-RNA; JURKAT T-CELLS; INSULIN-RESISTANCE; OXIDATIVE STRESS; L6 MYOTUBES; TNF-ALPHA; SEPSIS; EXPRESSION; ANTIOXIDANT AB In L6 myotubes, glucose uptake stimulated by interferon (IFN)-gamma or lipopolysaccharides (LPS) and a combination of LPS, IFN-gamma, and tumor necrosis factor (TNF)-alpha was inhibited by the antioxidant pyrrolidinedithiocarbamate and potentiated in reduced glutathione (GSH)-deficient cells. Also, the stimulatory effect of LPS and IFN-gamma individually, and of a combination of LPS, IFN-gamma, and TNF-alpha, on glucose uptake was associated with an increased level of intracellular oxidants (dichlorofluorescein assay) and loss of intracellular GSH. Study of the individual effects of LPS, IFN-gamma, and TNF-alpha as well as of a combination of the three activators provided evidence against a role of nitric oxide in mediating the stimulatory effect of the above-mentioned agents on glucose uptake. We also observed that the insulin-mimetic nutrient alpha-lipoic acid (LA; R-enantiomer) is able to stimulate glucose uptake in cytokine-treated cells that are insulin resistant. This study shows that cytokine-induced glucose uptake in skeletal muscle cells is redox sensitive and that, under conditions of acute infection that is accompanied with insulin resistance, LA may have therapeutic implications in restoring glucose availability in tissues such as the skeletal muscle. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, EETD, Dept Mol & Cell Biol, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Biol Technol Sect, Berkeley, CA 94720 USA. Univ Kuopio, Fac Med, Dept Physiol, FIN-70211 Kuopio, Finland. RP Sen, CK (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, EETD, Dept Mol & Cell Biol, Life Sci Addit,Bldg 20A,Rm 251,Mail Stop 3200, Berkeley, CA 94720 USA. EM cksen@socrates.berkeley.edu RI Sen, Chandan/A-8762-2013; Khanna, Savita/E-3378-2011; Roy, sashwati/E-3990-2011 FU NIDDK NIH HHS [DK-50430]; NIGMS NIH HHS [GM-27345] NR 49 TC 45 Z9 49 U1 0 U2 1 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0363-6119 J9 AM J PHYSIOL-REG I JI Am. J. Physiol.-Regul. Integr. Comp. Physiol. PD MAY PY 1999 VL 276 IS 5 BP R1327 EP R1333 PG 7 WC Physiology SC Physiology GA 194PE UT WOS:000080202100013 PM 10233023 ER PT J AU Novotny, TE Seward, J Sun, RK Acree, K AF Novotny, TE Seward, J Sun, RK Acree, K TI The "sausage factory" tour of the legislative process: An interactive orientation SO AMERICAN JOURNAL OF PUBLIC HEALTH LA English DT Article C1 Ctr Dis Control & Prevent, Publ Hlth Practice Program Off, Atlanta, GA USA. Univ Calif Berkeley, Sch Publ Hlth, Berkeley, CA 94720 USA. Lawrence Livermore Natl Lab, Livermore, CA USA. Calif Dept Hlth Serv, Sacramento, CA USA. RP Novotny, TE (reprint author), World Bank, Human Dev Network, Room G-3075,1818 H St NW, Washington, DC 20433 USA. EM tnovotny@worldbank.org FU NHLBI NIH HHS [HR95-265P] NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER PUBLIC HEALTH ASSOC INC PI WASHINGTON PA 1015 FIFTEENTH ST NW, WASHINGTON, DC 20005 USA SN 0090-0036 J9 AM J PUBLIC HEALTH JI Am. J. Public Health PD MAY PY 1999 VL 89 IS 5 BP 771 EP 773 DI 10.2105/AJPH.89.5.771 PG 3 WC Public, Environmental & Occupational Health SC Public, Environmental & Occupational Health GA 189RL UT WOS:000079919600023 PM 10224995 ER PT J AU Buchholz, BA Arjomand, A Dueker, SR Schneider, PD Clifford, AJ Vogel, JS AF Buchholz, BA Arjomand, A Dueker, SR Schneider, PD Clifford, AJ Vogel, JS TI Intrinsic erythrocyte labeling and attomole pharmacokinetic tracing of C-14-labeled folic acid with accelerator mass spectrometry SO ANALYTICAL BIOCHEMISTRY LA English DT Article DE intrinsic labeling; accelerator mass spectrometry; AMS; pharmacokinetics; folate; physiologic dose ID NEURAL-TUBE DEFECTS; FOLATE; RISK; FORTIFICATION; SENSITIVITY; METABOLISM; PREGNANCY; BENEFITS; DISEASE; LEVEL AB Long-term physiologic tracing of nutrients, toxins, and drugs in healthy subjects is not possible using traditional decay counting of radioisotopes or stable isotope mass spectrometry due to radiation exposure and limited sensitivity, respectively. A physiologic dose of C-14-labeled folic acid (35 mu g, 100 nCi) was ingested by a healthy adult male and followed for 202 days in plasma, erythrocytes, urine, and feces using accelerator mass spectrometry. All samples and generated wastes were classified nonradioactive and the subject received a lifetime-integrated radiological effective dose of only II mu Sv. Radiolabeled folate appeared in plasma 10 min after ingestion but did not appear in erythrocytes until 5 days later. Approximately 0.4% of the erythrocytes were intrinsically labeled with an average of 130 C-14 atoms during erythropoiesis from the pulse of plasma [C-14]folate. An appropriate radiocarbon-labeled precursor can intrinsically label DNA or a specific protein during synthesis and obtain limits of quantitation several orders of magnitude below that of stable isotope methods. (C) 1999 Academic Press. C1 Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94551 USA. Univ Calif Davis, Dept Nutr, Davis, CA 95616 USA. Univ Calif Davis, Davis Canc Ctr, Sacramento, CA 95817 USA. RP Buchholz, BA (reprint author), Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, POB 808,L-397, Livermore, CA 94551 USA. RI Buchholz, Bruce/G-1356-2011 FU NIDDK NIH HHS [DK-45939, DK-53801] NR 33 TC 41 Z9 41 U1 1 U2 4 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0003-2697 J9 ANAL BIOCHEM JI Anal. Biochem. PD MAY 1 PY 1999 VL 269 IS 2 BP 348 EP 352 DI 10.1006/abio.1999.4041 PG 5 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 192BX UT WOS:000080059300017 PM 10222009 ER PT J AU Ingram, JC Groenewold, GS Olson, JE Gianotto, AK McCurry, MO AF Ingram, JC Groenewold, GS Olson, JE Gianotto, AK McCurry, MO TI Identification of mineral phases on basalt surfaces by imaging SIMS SO ANALYTICAL CHEMISTRY LA English DT Article ID SPECTROSCOPY; NETWORK AB A method for the identification of mineral phases on basalt surfaces utilizing secondary ion mass spectrometry (SIMS) with imaging capability is described. The goal of this work is to establish the use of imaging SIMS for characterization of the surface of basalt. The basalt surfaces were examined by interrogating the intact basalt (heterogeneous mix of mineral phases) as well as mineral phases that have been separated from the basalt samples. Mineral separates from the basalt were used to establish reference spectra for the specific mineral phases. Electron microprobe and X-ray photoelectron spectroscopy were used as supplemental techniques for providing additional characterization of the basalt. Mineral phases that make up the composition of the basalt were identified from single-ion images which were statistically grouped. The statistical grouping is performed by utilizing a program that employs a generalized learning vector quantization technique. Identification of the mineral phases on the basalt surface is achieved by comparing the mass spectra from the statistically grouped regions of the basalt to the mass spectral results from the mineral separates. The results of this work illustrate the potential for using imaging SIMS to study adsorption chemistry at the top surface of heterogeneous mineral samples. C1 Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. Idaho State Univ, Dept Geol, Pocatello, ID 83209 USA. RP Ingram, JC (reprint author), Idaho Natl Engn & Environm Lab, POB 1625, Idaho Falls, ID 83415 USA. NR 22 TC 8 Z9 8 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD MAY 1 PY 1999 VL 71 IS 9 BP 1712 EP 1719 DI 10.1021/ac9811571 PG 8 WC Chemistry, Analytical SC Chemistry GA 192QP UT WOS:000080090700023 PM 21662812 ER PT J AU Khandurina, J Jacobson, SC Waters, LC Foote, RS Ramsey, JM AF Khandurina, J Jacobson, SC Waters, LC Foote, RS Ramsey, JM TI Microfabricated porous membrane structure for sample concentration and electrophoretic analysis SO ANALYTICAL CHEMISTRY LA English DT Article ID CAPILLARY ZONE ELECTROPHORESIS; HIGH-PERFORMANCE ELECTROPHORESIS; MICROCHIP ELECTROPHORESIS; PARTICULARLY BIOPOLYMERS; POSTCOLUMN REACTOR; PCR AMPLIFICATION; MICROLITER SCALE; DILUTE SAMPLES; GLASS CHIPS; SEPARATIONS AB A microfabricated injection valve incorporating a porous membrane structure is reported that enables electrokinetic concentration of DNA samples using homogeneous buffer conditions followed by injection into a channel for electrophoretic analysis. The porous membrane was incorporated in the microchannel manifold by having two channels separated from each other by 3-12 mu m and connected by a thin porous silicate layer. This design allows the passage of current to establish an electrical connection between the separated channels but prevents large molecules, e.g., DNA, from traversing the membrane. Concentrated DNA can be injected into the separation channel and electrophoretically analyzed. Experiments exhibit a nonlinear increase in concentration with time, and DNA fragments can be concentrated up to 2 orders of magnitude as shown by comparison of peak intensities for analysis performed with and without concentration. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Ramsey, JM (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, POB 2008, Oak Ridge, TN 37831 USA. FU NHGRI NIH HHS [R01HG01398] NR 31 TC 192 Z9 196 U1 1 U2 21 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD MAY 1 PY 1999 VL 71 IS 9 BP 1815 EP 1819 DI 10.1021/ac981161c PG 5 WC Chemistry, Analytical SC Chemistry GA 192QP UT WOS:000080090700038 PM 10330910 ER PT J AU Stockwell, CA Weeks, SC AF Stockwell, Craig A. Weeks, Stephen C. TI Translocations and rapid evolutionary responses in recently established populations of western mosquitofish (Gambusia affinis) SO ANIMAL CONSERVATION LA English DT Article AB The response of quantitative traits in translocated populations has not been well explored. Evolutionary shifts in quantitative traits, such as life history characteristics, are of particular interest because of their obvious association with fitness. In a recent survey, Stockwell (1995) examined life history variation of four populations of western mosquitofish (Gambusia affinis) that were derived from a common ancestral population 55-58 years earlier. Three life history traits differed considerably among the four sites and appeared to be correlated with local environmental conditions. To test whether these differences were due to plasticity or rapid evolution, fish from the four sites were maintained under common-garden conditions for two generations. After two generations a genetic basis was inferred for two of the three traits (size at maturity and fat content), but not for the third trait (offspring size). Thus, rapid evolution had occurred for two life history traits in these recently established populations. This case of rapid life history evolution may be due to genetic drift and/or natural selection. These data suggest that translocations may lead to rapid evolutionary responses of targeted taxa. Rapid evolutionary responses are of special concern for 'refuge' populations that are maintained as a hedge against extinction. C1 [Stockwell, Craig A.] Univ Nevada, Program Ecol Evolut & Conservat Biol, Reno, NV 89557 USA. [Stockwell, Craig A.] Univ Nevada, Biol Resources Res Ctr, Dept Biol, Reno, NV 89557 USA. [Weeks, Stephen C.] Univ Akron, Dept Biol, Akron, OH 44325 USA. [Weeks, Stephen C.] Univ Georgia, Savannah River Ecol Lab, Aiken, SC 29802 USA. RP Stockwell, CA (reprint author), N Dakota State Univ, Dept Zool, Stevens Hall, Fargo, ND 58105 USA. EM cstockwe@plains.nodak.edu FU Biodiversity Research Center at the University of Nevada Reno; Sigma-Xi; U. S. Department of Energy; University of Georgia's Savannah River Ecology Laboratory; [DE-AC09-76SR00819] FX We thank S. Diaz-Conde, S. Lee, T. Miettunen and A. Yuan for assistance with the data collection. G. Meffe graciously provided laboratory space, supplies and logistical support. We are appreciative of constructive comments that were provided by P. Brussard, P. Dixon, M. Draney, K. Garrett, K. Gubista, G. Hoelzer, S. Jenkins, K. Kandl, W. Longland, G. Meffe, M. Mulvey, G. Vinyard and two anonymous reviewers. Thanks to A. Hendry for sharing an unpublished manuscript. This work was funded by the Biodiversity Research Center at the University of Nevada Reno and a Sigma-Xi Grant to C. A. S. and by contract DE-AC09-76SR00819 between the U. S. Department of Energy and the University of Georgia's Savannah River Ecology Laboratory.; We dedicate this paper to the memory of Dr Gary L. Vinyard, teacher, mentor and friend. NR 48 TC 43 Z9 46 U1 2 U2 23 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 1367-9430 J9 ANIM CONSERV JI Anim. Conserv. PD MAY PY 1999 VL 2 IS 2 BP 103 EP 110 DI 10.1111/j.1469-1795.1999.tb00055.x PG 8 WC Biodiversity Conservation; Ecology SC Biodiversity & Conservation; Environmental Sciences & Ecology GA V71EH UT WOS:000204810700004 ER PT J AU Kollman, C Baggerly, K Cox, D Picard, R AF Kollman, C Baggerly, K Cox, D Picard, R TI Adaptive importance sampling on discrete Markov chains SO ANNALS OF APPLIED PROBABILITY LA English DT Article DE adaptive procedures; exponential convergence; Monte Carlo; particle transport; zero-variance solution ID MONTE-CARLO AB In modeling particle transport through a medium, the path of a particle behaves as a transient Markov chain. We are interested in characteristics of the particle's movement conditional on its starting state, which take the form of a "score" accumulated with each transition. Importance sampling is an essential variance reduction technique in this setting, and we provide an adaptive (iteratively updated) importance sampling algorithm that converges exponentially to the solution. Examples illustrating this phenomenon are provided. C1 Natl Marrow Donor Program, Minneapolis, MN 55413 USA. Rice Univ, Dept Stat, Houston, TX 77251 USA. Univ Calif Los Alamos Natl Lab, Stat Grp, Los Alamos, NM 87545 USA. RP Kollman, C (reprint author), Natl Marrow Donor Program, Minneapolis, MN 55413 USA. NR 17 TC 37 Z9 37 U1 0 U2 1 PU INST MATHEMATICAL STATISTICS PI HAYWARD PA IMS BUSINESS OFFICE-SUITE 7, 3401 INVESTMENT BLVD, HAYWARD, CA 94545 USA SN 1050-5164 J9 ANN APPL PROBAB JI Ann. Appl. Probab. PD MAY PY 1999 VL 9 IS 2 BP 391 EP 412 PG 22 WC Statistics & Probability SC Mathematics GA 208DJ UT WOS:000080974700008 ER PT J AU Hays, DC Cho, H Jung, KB Hahn, YB Abernathy, CR Pearton, SJ Ren, F Hun, J Shul, RJ AF Hays, DC Cho, H Jung, KB Hahn, YB Abernathy, CR Pearton, SJ Ren, F Hun, J Shul, RJ TI Selective dry etching using inductively coupled plasmas Part II. InN GaN and InN AlN SO APPLIED SURFACE SCIENCE LA English DT Article DE dry etching; ICl; IBr ID NITRIDES; GROWTH AB Two interhalogen plasma chemistries, ICI and IBr, have been examined for selective dry etching of InN over GaN and AIN. Maximum selectivities of 55 for InN/GaN and 20 for InN/AlN were achieved with ICI, and 30 for InN/GaN and 14 for InN/AlN, respectively, with IBr. There are two reasons for these results-the relatively high volatility of the InI3 etch product and the lower bond strength of InN relative to the other two binary nitrides. Both interhalogen plasma chemistries appear promising for use in electronic device fabrication. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Hays, DC (reprint author), Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. NR 24 TC 11 Z9 11 U1 2 U2 11 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1999 VL 147 IS 1-4 BP 134 EP 139 DI 10.1016/S0169-4332(99)00104-X PG 6 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA 205LE UT WOS:000080821900020 ER PT J AU Hahn, YB Hays, DC Cho, H Jung, KB Abernathy, CR Pearton, SJ Shul, RJ AF Hahn, YB Hays, DC Cho, H Jung, KB Abernathy, CR Pearton, SJ Shul, RJ TI Effect of inert gas additive species on Cl-2 high density plasma etching of compound semiconductors Part I. GaAs and GaSb SO APPLIED SURFACE SCIENCE LA English DT Article DE inert gas; GaAs; GaSb ID INDUCTIVELY-COUPLED PLASMA; INP; CHEMISTRIES; DAMAGE; BCL3; ALN AB The role of the inert gas additive (He, Ar, Xe) to Cl-2 Inductively Coupled Plasmas for dry etching of GaAs and GaSb was examined through the effect on etch rate, surface roughness and near-surface stoichiometry. The etch rates for both materials go through a maximum with Cl-2% in each type of discharge (Cl-2/He, Cl-2/Ar, Cl-2/Xe), reflecting the need to have efficient ion-assisted desorption of the etch products. Etch yields initially increase strongly with source power as the chlorine neutral density increases, but decrease again at high powers as the etching becomes reactant-limited. The etched surfaces are generally smoother with Ar or Xe addition, and maintain their stoichiometry. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Pearton, SJ (reprint author), Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. NR 20 TC 15 Z9 16 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1999 VL 147 IS 1-4 BP 207 EP 214 DI 10.1016/S0169-4332(99)00114-2 PG 8 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA 205LE UT WOS:000080821900027 ER PT J AU Hahn, YB Hays, DC Cho, H Jung, KB Abernathy, CR Pearton, SJ Shul, RJ AF Hahn, YB Hays, DC Cho, H Jung, KB Abernathy, CR Pearton, SJ Shul, RJ TI Effect of inert gas additive species on Cl-2 high density plasma etching of compound semiconductors Part II. InP, InSb, InGaP and InGaAs SO APPLIED SURFACE SCIENCE LA English DT Article DE inert gas; plasma etching; etch rate; semiconductor ID V SEMICONDUCTORS; GAAS AB The effects of the additive noble gases He, Ar and Xe on chlorine-based inductively coupled plasma etching of InP, InSb, InGaP and InGaAs were studied as a function of source power, chuck power and discharge composition. The etch rates of all materials with Cl-2/He and Cl-2/Xe are greater than with Cl-2/Ar. Etch rates in excess of 4.8 mu m/min for InP and InSb with Cl-2/He or Cl-2/Xe, 0.9 mu m/min for InGaP with Cl-2/Xe, and 3.8 mu m/min for InGaAs with Cl-2/Xe were obtained at 750 W ICP power, 250 W rf power, similar to 15% Cl-2 and 5 mTorr. All three plasma chemistries produced smooth morphologies for the etched InGaP surfaces, while the etched surface of InP showed rough morphology under all conditions. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Pearton, SJ (reprint author), Univ Florida, Dept Mat Sci & Engn, POB 116400,132 Rhines Hall, Gainesville, FL 32611 USA. NR 15 TC 15 Z9 20 U1 3 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1999 VL 147 IS 1-4 BP 215 EP 221 DI 10.1016/S0169-4332(99)00115-4 PG 7 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA 205LE UT WOS:000080821900028 ER PT J AU Sherman, M AF Sherman, M TI Indoor air quality for residential buildings SO ASHRAE JOURNAL LA English DT Article AB ASHRAE has long been in the business of ventilation, but most of the focus of that effort has been in the area of commercial and institutional buildings. Residential ventilation traditionally was not a major concern because it was felt that between operable windows and envelope leakage, people were getting enough air. In the quarter of a century since the first oil shock, houses have become much more energy efficient. At the same time, the kinds of materials and functions in houses were changing in character in response to people's needs. People also were becoming more environmentally conscious not only about the resources they were consuming but about the environment in which they lived. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Energy Performance Bldg Grp, Berkeley, CA 94720 USA. RP Sherman, M (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Energy Performance Bldg Grp, Berkeley, CA 94720 USA. NR 0 TC 2 Z9 2 U1 0 U2 3 PU AMER SOC HEATING REFRIGERATING AIR-CONDITIONING ENG, INC, PI ATLANTA PA 1791 TULLIE CIRCLE NE, ATLANTA, GA 30329 USA SN 0001-2491 J9 ASHRAE J JI ASHRAE J. PD MAY PY 1999 VL 41 IS 5 BP 26 EP 30 PG 5 WC Thermodynamics; Construction & Building Technology; Engineering, Mechanical SC Thermodynamics; Construction & Building Technology; Engineering GA 234QC UT WOS:000082494900008 ER PT J AU Baker, P Benoit, R Bibel, DJ Brock, T Chung, KT Domer, J Eveleigh, D Faison, B Isenberg, H Jannasch, H Lederberg, J Schaechter, M Schmidt, M Silver, S Summer, W Whitt, D AF Baker, P Benoit, R Bibel, DJ Brock, T Chung, KT Domer, J Eveleigh, D Faison, B Isenberg, H Jannasch, H Lederberg, J Schaechter, M Schmidt, M Silver, S Summer, W Whitt, D TI Microbiology's fifty most significant events during the past 125 years ... SO ASM NEWS LA English DT Article C1 NIAID, Bethesda, MD 20892 USA. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. Elie Metchnikoff Mem Lib, San Francisco, CA USA. Univ Wisconsin, Madison, WI 53706 USA. Univ Memphis, Memphis, TN 38152 USA. Appalachian State Univ, Boone, NC 28608 USA. Rutgers State Univ, New Brunswick, NJ 08903 USA. Oak Ridge Natl Lab, Oak Ridge, TN USA. Long Isl Jewish Med Ctr, New Hyde Park, NY 11042 USA. Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA. Rockefeller Univ, New York, NY 10021 USA. San Diego State Univ, San Diego, CA 92182 USA. Med Univ S Carolina, Charleston, SC 29425 USA. Univ Illinois, Coll Med, Chicago, IL USA. Yale Univ, New Haven, CT USA. Univ Illinois, Urbana, IL 61801 USA. NR 0 TC 0 Z9 0 U1 0 U2 2 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 USA SN 0044-7897 J9 ASM NEWS JI ASM News PD MAY PY 1999 VL 65 IS 5 BP U7 EP + PG 10 WC Microbiology SC Microbiology GA 196HY UT WOS:000080304000011 ER PT J AU Revnivtsev, MG Emel'yanov, AN Borozdin, KN AF Revnivtsev, MG Emel'yanov, AN Borozdin, KN TI X-ray outburst of the symbiotic star CI Cam XTE J0421+560: RXTE observations SO ASTRONOMY LETTERS-A JOURNAL OF ASTRONOMY AND SPACE ASTROPHYSICS LA English DT Article AB The RXTE observations of the X-ray transient XTE J0421+/-560/CI Cam in early April 1998 are presented. The all-sky monitor (ASM) light curve exhibits an unusually rapid decline in the object's luminosity. The PCA and HEXTE spectra taken during a series of observations of the object are analyzed in detail. Two emission lines at energies similar to 6.5 and 8 keV were detected. The possibility of the observed X-ray emission being generated in a relativistic plasma jet is considered. An analogy with the well-known Galactic source SS 433 is noted. C1 Russian Acad Sci, Space Res Inst, Moscow 117810, Russia. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. RP Revnivtsev, MG (reprint author), Russian Acad Sci, Space Res Inst, Ul Profsoyuznaya 84-32, Moscow 117810, Russia. NR 17 TC 14 Z9 14 U1 0 U2 0 PU MAIK NAUKA/INTERPERIODICA PUBL PI WOODBURY PA C/O AMERICAN INST PHYSICS, 500 SUNNYSIDE BLVD, MEMBER SUBSCRIBER SERVICES, WOODBURY, NY 11797-2999 USA SN 1063-7737 J9 ASTRON LETT+ JI Astron. Lett.-J. Astron. Space Astrophys. PD MAY PY 1999 VL 25 IS 5 BP 294 EP 306 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 203FQ UT WOS:000080697900002 ER PT J AU Kinney, WH Riotto, A AF Kinney, WH Riotto, A TI Dynamical supersymmetric inflation SO ASTROPARTICLE PHYSICS LA English DT Article ID COSMOLOGICAL PERTURBATIONS; DENSITY PERTURBATIONS; UNIVERSE SCENARIO; SCALE; BREAKING; FLATNESS; HORIZON AB We propose a new class of inflationary models in which the scalar field potential governing inflation is generated by the same nonperturbative gauge dynamics that may lead to supersymmetry breaking. Such models satisfy constraints from cosmic microwave background measurements for natural values of the fundamental parameters in the theory. In addition, they have two particularly interesting characteristics: a "blue" spectrum of scalar perturbations, and an upper bound on the total amount of inflation possible. (C) 1999 Elsevier Science B.V. C1 NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. EM kinneyw@fnal.gov; riotto@fnas01.fnal.gov NR 25 TC 30 Z9 30 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-6505 EI 1873-2852 J9 ASTROPART PHYS JI Astropart Phys. PD MAY PY 1999 VL 10 IS 4 BP 387 EP 395 DI 10.1016/S0927-6505(98)00057-7 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 194RA UT WOS:000080206300011 ER PT J AU Arav, N Korista, KT De Kool, M Junkkarinen, VT Begelman, MC AF Arav, N Korista, KT De Kool, M Junkkarinen, VT Begelman, MC TI Hubble Space Telescope observations of the broad absorption line quasar PG 0946+301 SO ASTROPHYSICAL JOURNAL LA English DT Article DE quasars : absorption lines; quasars : individual (PG 0946+301) ID ACTIVE GALACTIC NUCLEI; RADIATIVE ACCELERATION; STELLAR OBJECTS; ATOMIC DATA; DISK WINDS; BAL QSOS; X-RAY; OUTFLOWS; MODELS; IONIZATION AB We analyze Hubble Space Telescope (HST) and ground-based spectra of the brightest broad absorption line (BAL) quasar in the UV: PG 0946 + 301. A detailed study of the absorption troughs as a function of velocity is presented, facilitated by the use of a new algorithm to solve for the optical depth as a function of velocity for multiplet lines. We find convincing evidence for saturation in parts of the troughs. This supports our previous assertion that saturation is common in BALs and therefore cast doubts on claims for very high metallicity in BAL flows. Because of the importance of BAL saturation we also discuss its evidence in other objects. In PG 0946+301 large differences in ionization as a function of velocity are detected, and our findings support the hypothesis that the line of sight intersects a number of flow components that combine to give the appearance of the whole trough. Based on the optical depth profiles, we develop a geometrical-kinematical model for the flow. We have positively identified 16 ions of eight elements (H I, C III, C IV, N III, N IV, N V, O III, O IV, O V, O VI, Ne V, Ne VIII, P V, Si IV, S V, S VI) and have probable identifications of Mg x and S Iv. Unlike earlier analysis of IUE data, we find no evidence for BALs arising from excited ionic states in the HST spectrum of PG 0946 + 301. C1 Univ Calif Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. Western Michigan Univ, Dept Phys, Kalamazoo, MI 49008 USA. Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. ANU, Astrophys Theory Ctr, Canberra, ACT 0200, Australia. Univ Calif San Diego, Ctr Astrophys & Space Sci, La Jolla, CA 92093 USA. Univ Colorado, Dept Astrophys, Boulder, CO 80309 USA. RP Arav, N (reprint author), Univ Calif Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, L-413,POB 808, Livermore, CA 94550 USA. NR 40 TC 86 Z9 86 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1999 VL 516 IS 1 BP 27 EP 46 DI 10.1086/307073 PN 1 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 202NX UT WOS:000080660000004 ER PT J AU Tran, HD Brotherton, MS Stanford, SA van Breugel, W Dey, A Stern, D Antonucci, R AF Tran, HD Brotherton, MS Stanford, SA van Breugel, W Dey, A Stern, D Antonucci, R TI A polarimetric search for hidden quasars in three radio-selected ultraluminous infrared galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : Seyfert; galaxies : starburst; infrared : galaxies; polarization ID ACTIVE GALACTIC NUCLEI; SEYFERT 2 GALAXIES; BROAD-LINE REGIONS; IRAS F15307+3252; SKY SURVEY; CYGNUS-A; EMISSION; SPECTROPOLARIMETRY; POLARIZATION; ORIGIN AB We have carried out a spectropolarimetric search far hidden broad-line quasars in three ultraluminous infrared galaxies (ULIRGs) discovered in the positional correlations between sources detected in deep radio surveys and the IRAS Faint Source Catalog. Only the high-ionization Seyfert 2 galaxy TF J1736 + 1122 is highly polarized, displaying a broad-line spectrum visible in polarized light. The other two objects, TF J1020 + 6436 and FF J1614 + 3234, display spectra dominated by a population of young (A type) stars similar to those of "E + A" galaxies. They are unpolarized, showing no sign of hidden broad-line regions. The presence of young starburst components in all three galaxies indicates that the ULIRG phenomenon encompasses both active galactic nuclei (AGNs) and starburst activity, but the most energetic ULIRGs do not necessarily harbor "buried quasars." We find that a luminous infrared galaxy is most likely to host an obscured quasar if it exhibits a high-ionization ([O III] lambda 5007/H beta greater than or similar to 5) spectrum typical of a "classic" Seyfert 2 galaxy with little or no Balmer absorption lines, is "ultraluminous" (L(IR) greater than or similar to 10(12) L(.)), and has a "warm" IR color (f(25)/f(60) greater than or similar to 0.25). The detection of hidden quasars in this group but not in the low-ionization, starburst-dominated ULIRGs (classified as LINERs or H II galaxies) may indicate an evolutionary connection, with the latter being found in younger systems. C1 Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. RP Tran, HD (reprint author), Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, 7000 E Ave,POB 808,L413, Livermore, CA 94550 USA. EM htran@igpp.llnl.gov NR 94 TC 25 Z9 25 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1999 VL 516 IS 1 BP 85 EP 96 DI 10.1086/307103 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 202NX UT WOS:000080660000008 ER PT J AU Carr, BJ Sakellariadou, M AF Carr, BJ Sakellariadou, M TI Dynamical constraints on dark matter in compact objects SO ASTROPHYSICAL JOURNAL LA English DT Review DE black hole physics; dark matter; galaxies : star clusters ID MASSIVE BLACK-HOLES; VELOCITY-DISPERSION-RELATION; LIGHT-ELEMENT NUCLEOSYNTHESIS; BIG-BANG NUCLEOSYNTHESIS; LARGE-MAGELLANIC-CLOUD; POPULATION-III STARS; LYMAN-ALPHA FOREST; GALACTIC DISK; GLOBULAR-CLUSTERS; DEUTERIUM ABUNDANCE AB Many of the baryons in the universe are dark and at least some of the dark baryons could be in the form of compact objects. Such objects could be in various locations-galactic disks, galactic halos, clusters of galaxies, or intergalactic space-and each of these is associated with a dark matter problem. For each site we consider the various dynamical constraints that can be placed on the fraction of the dark matter in compact objects of different mass. Small compact objects in the Galaxy are constrained by upper limits on their encounter rate with the Earth and solar system since they would resemble meteors or comets. Larger objects are constrained by the disruptive or disturbing effects they would have on various astronomical systems. For disk objects, time most interesting constraints come from the disruption of binary stars or open star clusters. For halo objects, they come from the disruption of globular clusters, the heating of the Galactic disk, and their accumulation in the Galactic nucleus as a result of dynamical friction. For cluster objects, they come from the tidal distortion and disruption of galaxies. For intergalactic objects, they come from the upper limit on the peculiar motions induced in galaxies. We also apply these limits to the situation in which the compact objects are clusters of smaller objects. C1 Queen Mary Univ London, Astron Unit, London E1 4NS, England. NASA, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. Univ Geneva, Dept Phys Theor, CH-1211 Geneva 4, Switzerland. RP Carr, BJ (reprint author), Queen Mary Univ London, Astron Unit, Mile End Rd, London E1 4NS, England. NR 176 TC 38 Z9 38 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1999 VL 516 IS 1 BP 195 EP 220 DI 10.1086/307071 PN 1 PG 26 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 202NX UT WOS:000080660000017 ER PT J AU Kraeft, WD Arndt, S Dappen, W Nayfonov, A AF Kraeft, WD Arndt, S Dappen, W Nayfonov, A TI A comment on "On density-dependent and temperature-dependent ground-state and continuum effects in the equation of state for stellar interiors" SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic processes; equation of state; stars : interiors ID ENERGY AB Misunderstandings have occurred regarding the conclusions of the paper "On Density-dependent and Temperature-dependent Ground-State and Continuum Effects in the Equation of State for Stellar Interiors" by S. Arndt, W. Dappen, & A. Nayfonov (1998, ApJ, 498, 349). On occasion, its results have been interpreted as if it showed basic flaws in the general theory of dynamical screening. The aim of this comment is to emphasize the context in which the conclusions of the paper must be understood in order to avoid misinterpretations. C1 Univ Greifswald, Inst Phys, D-17489 Greifswald, Germany. Max Planck Inst Plasmaphys, D-17489 Greifswald, Germany. Univ So Calif, Dept Phys & Astron, Los Angeles, CA 90089 USA. Aarhus Univ, Inst Phys & Astron, Theoret Astrophys Ctr, DK-8000 Aarhus C, Denmark. Univ Calif Lawrence Livermore Natl Lab, IGPP, Livermore, CA 94550 USA. RP Kraeft, WD (reprint author), Univ Greifswald, Inst Phys, D-17489 Greifswald, Germany. NR 4 TC 4 Z9 4 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1999 VL 516 IS 1 BP 369 EP 370 DI 10.1086/307088 PN 1 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 202NX UT WOS:000080660000034 ER PT J AU Jong, M Zhu, Y Gong, E Frazer, K Cheng, JF Rubin, E AF Jong, M Zhu, Y Gong, E Frazer, K Cheng, JF Rubin, E TI A targeted 450 kappa b deletion in mouse chromosome 11 identifies a novel gene that dramatically impacts on triglyceride production SO ATHEROSCLEROSIS LA English DT Meeting Abstract C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Genome Sci, Div Life Sci, Berkeley, CA 94720 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCI IRELAND LTD PI CLARE PA CUSTOMER RELATIONS MANAGER, BAY 15, SHANNON INDUSTRIAL ESTATE CO, CLARE, IRELAND SN 0021-9150 J9 ATHEROSCLEROSIS JI Atherosclerosis PD MAY PY 1999 VL 144 SU 1 BP 18 EP 19 DI 10.1016/S0021-9150(99)80066-5 PG 2 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 203BM UT WOS:000080687500067 ER PT J AU Campos, E Blanche, PJ Kotite, L Krauss, RM Havel, RJ AF Campos, E Blanche, PJ Kotite, L Krauss, RM Havel, RJ TI Characterization of remnant-like lipoprotein particles isolated by immunoaffinity gel from subjects with LDL subclass phenotypes A and B SO ATHEROSCLEROSIS LA English DT Meeting Abstract C1 Univ Calif San Francisco, Inst Cardiovasc Res, San Francisco, CA 94143 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCI IRELAND LTD PI CLARE PA CUSTOMER RELATIONS MANAGER, BAY 15, SHANNON INDUSTRIAL ESTATE CO, CLARE, IRELAND SN 0021-9150 J9 ATHEROSCLEROSIS JI Atherosclerosis PD MAY PY 1999 VL 144 SU 1 BP 88 EP 88 DI 10.1016/S0021-9150(99)80336-0 PG 1 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 203BM UT WOS:000080687500337 ER PT J AU Krauss, RM Dreon, DM Blanche, PJ Cantor, RM Davis, R Lanning, CD Rawlings, RS Fernstrom, HS Holl, LG Orr, JR Scheuner, MT Wen, PZ Lusis, AJ Rotter, JI AF Krauss, RM Dreon, DM Blanche, PJ Cantor, RM Davis, R Lanning, CD Rawlings, RS Fernstrom, HS Holl, LG Orr, JR Scheuner, MT Wen, PZ Lusis, AJ Rotter, JI TI Genetic influences on dietary fat-induced changes in low density lipoprotein subclass phenotypes SO ATHEROSCLEROSIS LA English DT Meeting Abstract C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Cedars Sinai Res Inst, Los Angeles, CA USA. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCI IRELAND LTD PI CLARE PA CUSTOMER RELATIONS MANAGER, BAY 15, SHANNON INDUSTRIAL ESTATE CO, CLARE, IRELAND SN 0021-9150 J9 ATHEROSCLEROSIS JI Atherosclerosis PD MAY PY 1999 VL 144 SU 1 BP 90 EP 91 DI 10.1016/S0021-9150(99)80347-5 PG 2 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 203BM UT WOS:000080687500348 ER PT J AU Jong, M Zhu, Y Gong, E Frazer, K Cheng, JF Rubin, E AF Jong, M Zhu, Y Gong, E Frazer, K Cheng, JF Rubin, E TI A targeted 450 Kb deletion in mouse chromosome 11 identifies a novel gene that dramatically impacts on triglyceride production SO ATHEROSCLEROSIS LA English DT Meeting Abstract C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Genome Sci, Div Life Sci, Berkeley, CA 94720 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCI IRELAND LTD PI CLARE PA CUSTOMER RELATIONS MANAGER, BAY 15, SHANNON INDUSTRIAL ESTATE CO, CLARE, IRELAND SN 0021-9150 J9 ATHEROSCLEROSIS JI Atherosclerosis PD MAY PY 1999 VL 144 SU 1 BP 167 EP 167 DI 10.1016/S0021-9150(99)80640-6 PG 1 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 203BM UT WOS:000080687500642 ER PT J AU Garten, CT Post, WM Hanson, PJ Cooper, LW AF Garten, CT Post, WM Hanson, PJ Cooper, LW TI Forest soil carbon inventories and dynamics along an elevation gradient in the southern Appalachian Mountains SO BIOGEOCHEMISTRY LA English DT Article DE climate; C/N ratios; light-fraction organic matter; particulate organic matter; soil C turnover ID NATURAL C-13 ABUNDANCE; ORGANIC-MATTER; LIGHT-FRACTION; PHYSICAL SEPARATION; LAND-USE; TURNOVER; NITROGEN; ECOSYSTEMS; STORAGE; TEMPERATURE AB Soil organic carbon (SOC) was partitioned between unprotected and protected pools in six forests along an elevation gradient in the southern Appalachian Mountains using two physical methods: flotation in aqueous CaCl2 (1.4 g/mL) and wet sieving through a 0.053 mm sieve. Both methods produced results that were qualitatively and quantitatively similar. Along the elevation gradient, 28 to 53% of the SOC was associated with an unprotected pool that included forest floor O-layers and other labile soil organic matter (SOM) in various stages of decomposition. Most (71 to 83%) of the C in the mineral soil at the six forest sites was identified as protected because of its association with a heavy soil fraction (> 1.4 g/mL) or a silt-clay soil fraction. Total inventories of SOC in the forests (to a depth of 30 cm) ranged from 384 to 1244 mg C/cm(2). The turnover time of the unprotected SOC was negatively correlated (r = -0.95, p < 0.05) with mean annual air temperature (MAT) across the elevation gradient. Measured SOC inventories, annual C returns to the forest floor, and estimates of C turnover associated with the protected soil pool were used to parameterize a simple model of SOC dynamics. Steady-state predictions with the model indicated that, with no change in C inputs, the low- (235-335 m), mid- (940-1000 m), and high- (1650-1670 m) elevation forests under study might surrender approximate to 40 to 45% of their current SOC inventory following a 4 degrees C increase in MAT. Substantial losses of unprotected SOM as a result of a warmer climate could have long term impacts on hydrology, soil quality, and plant nutrition in forest ecosystems throughout the southern Appalachian Mountains. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Garten, CT (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. RI Hanson, Paul J./D-8069-2011; Post, Wilfred/B-8959-2012; Cooper, Lee/E-5251-2012 OI Hanson, Paul J./0000-0001-7293-3561; Cooper, Lee/0000-0001-7734-8388 NR 44 TC 89 Z9 130 U1 3 U2 27 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0168-2563 J9 BIOGEOCHEMISTRY JI Biogeochemistry PD MAY PY 1999 VL 45 IS 2 BP 115 EP 145 DI 10.1007/BF01106778 PG 31 WC Environmental Sciences; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Geology GA 186EZ UT WOS:000079716600001 ER PT J AU Hlavacek, WS Perelson, AS Sulzer, B Bold, J Paar, J Gorman, W Posner, RG AF Hlavacek, WS Perelson, AS Sulzer, B Bold, J Paar, J Gorman, W Posner, RG TI Quantifying aggregation of IgE-Fc epsilon RI by multivalent antigen SO BIOPHYSICAL JOURNAL LA English DT Article ID BASOPHILIC LEUKEMIA-CELLS; BIVALENT PENICILLOYL HAPTENS; HISTAMINE-RELEASE; IMMUNOGLOBULIN-E; CROSS-LINKING; MAST-CELLS; EQUILIBRIUM BINDING; RECEPTOR COMPLEXES; ZETA-PHOSPHORYLATION; MONOCLONAL-ANTIBODY AB Aggregation of cell surface receptors by multivalent ligand can trigger a variety of cellular responses. A well-studied receptor that responds to aggregation is the high affinity receptor for IgE (Fc epsilon RI), which is responsible for initiating allergic reactions. To quantify antigen-induced aggregation of IgE-Fc epsilon RI complexes, we have developed a method based on multiparameter flow cytometry to monitor both occupancy of surface IgE combining sites and association of antigen with the cell surface. The number of bound IgE combining sites in excess of the number of bound antigens, the number of bridges between receptors, provides a quantitative measure of IgE-Fc epsilon RI aggregation. We demonstrate our method by using it to study the equilibrium binding of a haptenated fluorescent protein, 2,4-dinitrophenol-coupled B-phycoerythrin (DNP25-PE), to fluorescein isothiocyanate-labeled anti-DNP IgE on the surface of rat basophilic leukemia cells. The results, which we analyze with the aid of a mathematical model, indicate how IgE-FceRI aggregation depends on the total concentrations of DNP25-PE and surface IgE. As expected, we find that maximal aggregation occurs at an optimal antigen concentration. We also find that aggregation varies qualitatively with the total concentration of surface IgE as predicted by an earlier theoretical analysis. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. No Arizona Univ, Dept Chem, Flagstaff, AZ 86011 USA. No Arizona Univ, Dept Biol, Flagstaff, AZ 86011 USA. RP Perelson, AS (reprint author), Los Alamos Natl Lab, POB 1663,MS K710, Los Alamos, NM 87545 USA. FU NCRR NIH HHS [RR06555]; NIAID NIH HHS [AI35997, AI28433] NR 70 TC 26 Z9 27 U1 0 U2 5 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD MAY PY 1999 VL 76 IS 5 BP 2421 EP 2431 PG 11 WC Biophysics SC Biophysics GA 195XZ UT WOS:000080278600009 PM 10233059 ER PT J AU Soukoulis, V Savikhin, S Xu, W Chitnis, PR Struve, WS AF Soukoulis, V Savikhin, S Xu, W Chitnis, PR Struve, WS TI Electronic spectra of PSI mutants: The peripheral subunits do not bind red chlorophylls in Synechocystis sp PCC 6803 SO BIOPHYSICAL JOURNAL LA English DT Article ID PHOTOSYSTEM-I; CORE ANTENNA; TEMPERATURE-DEPENDENCE; EXCITATION DYNAMICS; ENERGY-TRANSFER; SPECTROSCOPY; SIMULATIONS; PARTICLES; PCC-6803 AB Steady-state fluorescence and absorption spectra have been obtained in the Q(y) spectral region (690-780 nm and 600-750 nm, respectively) for several subunit-deficient photosystem I mutants from the cyanobacterium Synechocystis sp. PCC 6803. The 77 K fluorescence spectra of the wild-type and subunit-deficient mutant photosystem I particles are all very similar, peaking at similar to 720 nm with essentially the same excitation spectrum. Because emission from far-red chlorophylls absorbing near 708 nm dominates low-temperature fluorescence in Synechocystis sp., these pigments are not coordinated to any the subunits PsaF, Psa I, PsaJ, PsaK, PsaL, or psaM. The room temperature (wild-type-mutant) absorption difference spectra for trimeric mutants lacking the PsaF/J, PsaK, and PsaM subunits suggest that these mutants are deficient in core antenna chlorophylls (Chls) absorbing near 685, 670, 675, and 700 nm, respectively. The absorption difference spectrum for the PsaF/J/I/L-deficient photosystem I complexes at 5 K reveals considerably more structure than the room-temperature spectrum. The integrated absorbance difference spectra (when normalized to the total PS I Q(y) spectral area) are comparable to the fractions of Chls bound by the respective (groups of) subunits, according to the 4-Angstrom density map of PS I from Synechococcus elongatus. The spectrum of the monomeric PsaL-deficient mutant suggests that this subunit may bind pigments absorbing near 700 nm. C1 Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, Dept Biochem & Biophys, Ames, IA 50011 USA. US DOE, Ames Lab, Ames, IA 50011 USA. RP Struve, WS (reprint author), Iowa State Univ, Dept Chem, Gilman Hall, Ames, IA 50011 USA. NR 16 TC 25 Z9 25 U1 0 U2 4 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD MAY PY 1999 VL 76 IS 5 BP 2711 EP 2715 PG 5 WC Biophysics SC Biophysics GA 195XZ UT WOS:000080278600035 PM 10233085 ER PT J AU Fishman, MA Perelson, AS AF Fishman, MA Perelson, AS TI Th1/Th2 differentiation and cross-regulation SO BULLETIN OF MATHEMATICAL BIOLOGY LA English DT Article ID ANTIGEN-PRESENTING CELLS; CD4(+) T-CELLS; DENDRITIC CELLS; CYTOKINE PRODUCTION; MEDIATED-IMMUNITY; LEISHMANIA-MAJOR; INTERFERON-GAMMA; IN-VIVO; FUNCTIONAL DIVERSITY; AUTOIMMUNE-DISEASE AB The T helper (Th) phenotypes, Th1/Th2, are acquired upon interaction of a naive T helper cell and an antigen presenting cell (APC). Naive T helper cells may differentiate into either phenotype, and the actual outcome is determined by the density and avidity of the antigenic determinants presented by the APC, and the APCs inherent costimulatory properties. Until recently it was thought that differentiation is further affected by cytokines. However, Murphy et al. (1996, J. Exp. Med. 183, 901) have demonstrated that the experimental results, formerly interpreted as Th1/Th2 differentiation, in effect comprise an observation of two consecutive processes. (i) An interaction between naive T cells and APC creates a mixture of mature cells irreversibly committed to Th1 or Th2 phenotype. (ii) Subsequent addition of regulatory cytokines, promotes expansion of one phenotype while suppressing the other. The consequent shift in the per culture production of marker cytokines mimics the appearance of a cellular phenotype switch. We present and analyse a mathematical model that extrapolates these experimental facts into systemic behavior during an immune response. Despite the fact that differentiation produces cells of Th1 and Th2 phenotypes with the same receptor specificity, our results indicate that competition for antigenic stimulation, mediated by the APCs, combines with cytokine mediated cross-suppression between phenotypes to yield a response that is eventually dominated by T helper cells that are uniform in both receptor specificity (clonotype) and in cytokine secretion phenotype. (C) 1999 Society for Mathematical Biology. C1 Tel Aviv Univ, Fac Life Sci, Dept Zool, IL-69978 Tel Aviv, Israel. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Fishman, MA (reprint author), Tel Aviv Univ, Fac Life Sci, Dept Zool, IL-69978 Tel Aviv, Israel. EM maf@reef.tau.ac.il; maf@tl0.lanl.gov FU NIAID NIH HHS [AI28433] NR 69 TC 36 Z9 37 U1 3 U2 7 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0092-8240 J9 B MATH BIOL JI Bull. Math. Biol. PD MAY PY 1999 VL 61 IS 3 BP 403 EP 436 DI 10.1006/bulm.1998.0074 PG 34 WC Biology; Mathematical & Computational Biology SC Life Sciences & Biomedicine - Other Topics; Mathematical & Computational Biology GA 202VW UT WOS:000080673700001 PM 17883225 ER PT J AU Nishide, H Mizuma, H Tsuchida, E McBreen, J AF Nishide, H Mizuma, H Tsuchida, E McBreen, J TI Reversible stretching of a polymer-supported cobalt-chelate film in response to oxygen SO BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN LA English DT Article ID X-RAY ABSORPTION; COMPLEXES AB The polymer-supported N,N'-di(salicylidene)ethylenediaminatocobalt(II) [Co(salen)] took up oxygen through 2/1 Co/dioxygen adduct formation. The composite film of the polymer-supported [Co(salen)] and polymer layers reversibly bent under an oxygen and nitrogen atmosphere. The stretching was caused by a structural change in the [Co(salen)] crystal before and after the oxygen-binding, which was analyzed based on the near-IR spectral and density change as well as EXAFS. C1 Brookhaven Natl Lab, Div Mat Sci, Upton, NY 11973 USA. Waseda Univ, Dept Polymer Chem, Tokyo 1698555, Japan. RP Nishide, H (reprint author), Brookhaven Natl Lab, Div Mat Sci, Upton, NY 11973 USA. RI Nishide, Hiroyuki/A-8221-2012 OI Nishide, Hiroyuki/0000-0002-4036-4840 NR 21 TC 6 Z9 6 U1 0 U2 0 PU CHEMICAL SOC JAPAN PI TOKYO PA 1-5 KANDA-SURUGADAI CHIYODA-KU, TOKYO, 101-8307, JAPAN SN 0009-2673 EI 1348-0634 J9 B CHEM SOC JPN JI Bull. Chem. Soc. Jpn. PD MAY PY 1999 VL 72 IS 5 BP 1123 EP 1127 DI 10.1246/bcsj.72.1123 PG 5 WC Chemistry, Multidisciplinary SC Chemistry GA 206ZC UT WOS:000080909800031 ER PT J AU Finnin, MS Seltzer, S AF Finnin, MS Seltzer, S TI The secondary alpha-deuterium isotope effect at the site of the enzyme-catalyzed cis-trans isomerization of maleylacetone. Mechanistic implications SO CANADIAN JOURNAL OF CHEMISTRY-REVUE CANADIENNE DE CHIMIE LA English DT Article DE enzyme-catalyzed cis-trans isomerization; secondary alpha-deuterium isotope effect; maleylacetoacetate cis-trans isomerase; cis-trans isomerization mechanism ID ONE-STEP; ISOMERASE; GLUTATHIONE; SUBSTRATE; ACID; PUMP AB An equal mixture of monodeuterated isotopomers of maleylacetone, viz., 4-hydroxy-6-oxo-2,4-heptadienoic-2-d(1) acid (1) and 4-hydroxy-6-oxo-2,4-heptadienoic-3-d(1) acid (2) was synthesized and subjected to catalyzed cia-trans isomerization by the maleylacetoacetate cia-trans isomerase-glutathione system. These studies were designed to probe the detailed mechanism of enzyme-catalyzed cis-trans isomerization about the C-2-C-3 bond of the substrate. In the competitive reaction, 2 accumulates with respect to 1 at high extent of reaction. H-1 NMR analysis indicates that 1 reacts 15% faster than 2 in line with a nucleophilic addition mechanism at C-2 rather than a conjugate addition mechanism at C-2 and C-3, to convert the C-2-C-3 double bond to a single bond to allow facile internal rotation. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Seltzer, S (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. NR 28 TC 1 Z9 1 U1 0 U2 0 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0008-4042 J9 CAN J CHEM JI Can. J. Chem.-Rev. Can. Chim. PD MAY-JUN PY 1999 VL 77 IS 5-6 BP 557 EP 564 PG 8 WC Chemistry, Multidisciplinary SC Chemistry GA 219ND UT WOS:000081612600007 ER PT J AU Lee, HS Yang, XQ McBreen, J Vyprachticky, D Okamoto, Y AF Lee, HS Yang, XQ McBreen, J Vyprachticky, D Okamoto, Y TI New chloride anion receptors: trifluoromethyl sulfonylated polyamines SO CANADIAN JOURNAL OF CHEMISTRY-REVUE CANADIENNE DE CHIMIE LA English DT Article DE Cl- anion receptor; trifluoromethyl sulfonated tetraamine; ion pair dissociation ID <12>MERCURACARBORAND-4; MACROCYCLES; INCLUSION; COMPLEXES; BINDING; HOSTS; TIN AB A new chloride anion receptor, derivatized oligoethylene oxide CF3SO2 substituted tetraamine (3), was synthesized. This compound exhibited strong Cl-1 ion binding properties in nonpolar solvents such as benzene. Neutral red and Nile blue chloride dye molecules do not dissolve in benzene. However, when compound (3) was added to a benzene solution containing the solid dye compounds, the color of the solution immediately turned to dark blue, and the intensity of the color proportionally increased with the concentration of (3). The phenomena indicated that the Cl- ions of Neutral red or Nile blue chloride are complexed with (3), thereby resulting in an increase in the solubility of the Neutral red or Nile blue cations in benzene. The dissociation of chloride anions from 4,4',4 "-trimethoxytriphenyl chloromethane in a benzene solution proceeded with addition of compound (3) and increased with increasing time at room temperature. In contrast, another tetraamine compound (4) which was substituted with a less electron withdrawing group, CH3SO2, did not complex with Cl- anions in a benzene solution. C1 Polytech Univ, Dept Chem, Brooklyn, NY 11201 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Okamoto, Y (reprint author), Polytech Univ, Dept Chem, 6 Metrotech Ctr, Brooklyn, NY 11201 USA. RI Vyprachticky, Drahomir/H-2493-2014 OI Vyprachticky, Drahomir/0000-0003-4590-7522 NR 16 TC 2 Z9 2 U1 0 U2 3 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0008-4042 J9 CAN J CHEM JI Can. J. Chem.-Rev. Can. Chim. PD MAY-JUN PY 1999 VL 77 IS 5-6 BP 738 EP 743 PG 6 WC Chemistry, Multidisciplinary SC Chemistry GA 219ND UT WOS:000081612600030 ER PT J AU Vodovotz, Y Chesler, L Chong, HY Kim, SJ Simpson, JT DeGraff, W Cox, GW Roberts, AB Wink, DA Barcellos-Hoff, MH AF Vodovotz, Y Chesler, L Chong, HY Kim, SJ Simpson, JT DeGraff, W Cox, GW Roberts, AB Wink, DA Barcellos-Hoff, MH TI Regulation of transforming growth factor beta 1 by nitric oxide SO CANCER RESEARCH LA English DT Article ID CEREBRAL ENDOTHELIAL-CELLS; COLON CANCER LINES; MURINE MACROPHAGES; TUMOR-CELLS; TGF-BETA; FACTOR-ALPHA; TNF-ALPHA; RIBONUCLEOTIDE REDUCTASE; MOUSE MACROPHAGES; IL-8 EXPRESSION AB Many tumor cells or their secreted products suppress the function of tumor-infiltrating macrophages, Tumor cells often produce abundant transforming growth factor beta 1 (TGF-beta 1), which in addition to other immunosuppressive actions suppresses the inducible isoform of NO synthase, TGF-beta 1 is secreted in a latent form, which consists of TGF-beta 1 noncovalently associated with latency-associated peptide (LAP) and which can be activated efficiently by exposure to reactive oxygen species, Coculture of the human lung adenocarcinoma cell line A549 and ANA-1 macrophages activated with IFN-gamma plus lipopolysaccharide resulted in increased synthesis and activation of latent TGF-beta 1 protein by both A549 and ANA-1 cells, whereas unstimulated cultures of either cell type alone expressed only latent TGF-beta 1, We investigated whether exposure of tumor cells to NO influences the production, activation, or activity of TGF-beta 1. A549 human lung adenocarcinoma cells exposed to the chemical NO donor diethylamine-NONOate showed increased immunoreactivity of cell-associated latent and active TGF-beta 1 in a time- and dose-dependent fashion at 24-48 h after treatment. Exposure of latent TGF-beta 1 to solution sources of NO neither led to recombinant latent TGF-beta 1 activation nor modified recombinant TGF-beta 1 activity. A novel mechanism was observed, however: treatment of recombinant LAP with NO resulted in its nitrosylation and interfered with its ability to neutralize active TGF-beta 1, These results provide the first evidence that nitrosative stress influences the regulation of TGF-beta 1 and raise the possibility that NO production may augment TGP-beta 1 activity by modifying a naturally occurring neutralizing peptide. C1 NCI, Radiat Biol Branch, Bethesda, MD 20892 USA. NCI, Lab Cell Regulat & Carcinogenesis, Bethesda, MD 20892 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. NIMH, Lab Neurotoxicol, Bethesda, MD 20892 USA. Uniformed Serv Univ Hlth Sci, Dept Pharmacol, Bethesda, MD 20814 USA. RP Vodovotz, Y (reprint author), Cardiovasc Res Fdn, 110 Irving St NW,Suite 4B-1, Washington, DC 20010 USA. NR 78 TC 107 Z9 116 U1 0 U2 2 PU AMER ASSOC CANCER RESEARCH PI BIRMINGHAM PA PO BOX 11806, BIRMINGHAM, AL 35202 USA SN 0008-5472 J9 CANCER RES JI Cancer Res. PD MAY 1 PY 1999 VL 59 IS 9 BP 2142 EP 2149 PG 8 WC Oncology SC Oncology GA 192EW UT WOS:000080066300024 PM 10232601 ER PT J AU Melnick, RL Sills, RC Portier, CJ Roycroft, JH Chou, BJ Grumbein, SL Miller, RA AF Melnick, RL Sills, RC Portier, CJ Roycroft, JH Chou, BJ Grumbein, SL Miller, RA TI Multiple organ carcinogenicity of inhaled chloroprene (2-chloro-1,3-butadiene) in F344/N rats and B6C3F(1) mice and comparison of dose-response with 1,3-butadiene in mice SO CARCINOGENESIS LA English DT Article ID NATIONAL-TOXICOLOGY-PROGRAM; INHALATION EXPOSURE; MUTAGENICITY; CHLORIDE; ISOPRENE; TOXICITY; CHEMICALS; INFECTION; MORTALITY; PRODUCTS AB Chloroprene (2-chloro-1,3-butadiene) is a high production chemical used almost exclusively in the production of polychloroprene (neoprene) elastomer. Because of its structural similarity to 1,3-butadiene, a trans-species carcinogen, inhalation studies were performed with chloroprene to evaluate its carcinogenic potential in rats and mice. Groups of 50 male and female F344/N rats and 50 male and female B6C3F(1) mice were exposed to 0, 12.8, 32 or 80 p.p.m. chloroprene (6 h/day, 5 days/week) for 2 years. Under these conditions, chloroprene was carcinogenic to the oral cavity, thyroid gland, lung, kidney and mammary gland of rats, and to the lung, circulatory system (hemangiomas and hemangiosarcomas), Harderian gland, kidney, forestomach, liver, mammary gland, skin, mesentery and Zymbal's gland of mice. Survival adjusted tumor rates in mice were fit to a Weibull model for estimation of the shape of the dose-response curves, estimation of ED10 values (the estimated exposure concentration associated with an increased cancer risk of 10%) and comparison of these parameters with those for 1,3-butadiene. Butadiene has been identified as a potent carcinogen in mice and has been associated with increased risk of lymphatic and hematopoietic cancer in exposed workers. Shape parameter values for most of the neoplastic effects of chloroprene and 1,3-butadiene were consistent with linear or supralinear responses in the area near the lowest tested exposures. The most potent carcinogenic effect of 1,3-butadiene was the induction of lung neoplasms in female mice, which had an ED10 value of 0.3 p.p.m. Since the ED10 value for that same response in chloroprene exposed mice was also 0.3 p.p.m., we conclude that the carcinogenic potency of chloroprene in mice is similar to that of 1,3-butadiene. Cancer potency of chloroprene is greater in the mouse lung than in the rat lung, but greater in the rat kidney than in the mouse kidney and nearly equivalent in the mammary gland of each species. C1 NIEHS, Res Triangle Pk, NC 27709 USA. Pacific NW Lab, Richland, WA 99352 USA. RP Melnick, RL (reprint author), NIEHS, POB 12233, Res Triangle Pk, NC 27709 USA. RI Portier, Christopher/A-3160-2010 OI Portier, Christopher/0000-0002-0954-0279 NR 49 TC 26 Z9 26 U1 0 U2 2 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0143-3334 J9 CARCINOGENESIS JI Carcinogenesis PD MAY PY 1999 VL 20 IS 5 BP 867 EP 878 DI 10.1093/carcin/20.5.867 PG 12 WC Oncology SC Oncology GA 191KY UT WOS:000080022700017 PM 10334205 ER PT J AU Boorman, GA Anderson, LE Morris, JE Sasser, LB Mann, PC Grumbein, SL Hailey, JR McNally, A Sills, RC Haseman, JK AF Boorman, GA Anderson, LE Morris, JE Sasser, LB Mann, PC Grumbein, SL Hailey, JR McNally, A Sills, RC Haseman, JK TI Effect of 26 week magnetic field exposures in a DMBA initiation-promotion mammary gland model in Sprague-Dawley rats SO CARCINOGENESIS LA English DT Article ID BREAST-CANCER; ELECTROMAGNETIC-FIELDS; FEMALE RATS; CARCINOGENICITY; 50-HZ; TUMORIGENESIS; MORTALITY; WORKERS AB Several studies have suggested that exposure to 50 Hz magnetic fields promote chemically induced breast cancer in rats. Groups of 100 female Sprague-Dawley rats were initiated with a single 10 mg gavage dose of 7,12-dimethylbenz[a]anthracene (DMBA) at 50 days of age followed by exposure to ambient fields (sham exposed), 50 Hz magnetic fields at either 1 or 5 Gauss (G) field intensity or 60 Hz fields at 1 G for 18.5 h/day, 7 days/week for 26 weeks. A vehicle control group without DMBA was included. Rats were palpated weekly for the presence of tumors. There was no effect of magnetic field exposure on body weight gains or the time of appearance of mammary tumors, At the end of 26 weeks, the animals were killed and the mammary tumors counted and measured. Mammary gland masses found grossly were examined histologically, The mammary gland carcinoma incidence was 96, 90, 95 and 85% (P < 0.05, decrease) for the DMBA controls, 1 G 50 Hz, 5 G 50 Hz and 1 G 60 Hz groups, respectively. The total numbers of carcinomas were 649, 494 (P < 0.05, decrease), 547 and 433 (P < 0.05, decrease) for the DMBA controls, 1 G 50 Hz, 5 G 50 Hz and 1 G 60 Hz groups, respectively. The number of fibroadenomas varied from 276 to 319, with the lowest number in the 1 G 60 Hz exposure group. Measurement of the tumors revealed no difference in tumor size between groups. In this breast cancer initiation-promotion study in female Sprague-Dawley rats, there was no evidence that 50 or 60 Hz magnetic fields promoted breast cancer under the conditions of this assay. This study does not support the hypothesis that magnetic field exposure can promote breast cancer in this rat model. C1 NIEHS, Res Triangle Pk, NC 27709 USA. Pacific NW Lab, Richland, WA 99352 USA. Expt Pathol Lab, Res Triangle Pk, NC 27709 USA. RP Boorman, GA (reprint author), NIEHS, POB 12233, Res Triangle Pk, NC 27709 USA. FU NIEHS NIH HHS [N01-ES-65397] NR 26 TC 28 Z9 29 U1 0 U2 2 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0143-3334 J9 CARCINOGENESIS JI Carcinogenesis PD MAY PY 1999 VL 20 IS 5 BP 899 EP 904 DI 10.1093/carcin/20.5.899 PG 6 WC Oncology SC Oncology GA 191KY UT WOS:000080022700021 PM 10334209 ER PT J AU Sen, CK Roy, S Packer, L AF Sen, CK Roy, S Packer, L TI Fas mediated apoptosis of human Jurkat T-cells: intracellular events and potentiation by redox-active alpha-lipoic acid SO CELL DEATH AND DIFFERENTIATION LA English DT Article DE antioxidant; calcium; caspase; cell death; protein kinase c; signal transduction ID HUMAN-MALIGNANT GLIOMA; (CD95)-MEDIATED APOPTOSIS; CPP32-LIKE PROTEASES; CASPASE ACTIVITY; GENE-TRANSFER; NITRIC-OXIDE; CD95 LIGAND; IN-VIVO; ACTIVATION; KINASE AB Activation of caspases is required in Fas receptor mediated apoptosis. Maintenance of a reducing environment inside the cell has been suggested to be necessary for caspase activity during apoptosis. We explored the possibility to potentiate Fas mediated killing of tumor cells by alpha-lipoic acid (LA), a redox-active drug and nutrient that is intracellularly reduced to a potent reductant dihydrolipoic acid. Treatment of cells with 100 mu M LA for 72 h markedly potentiated Pas-mediated apoptosis of leukemic Jurkat cells but not that of peripheral blood lymphocytes from healthy humans. In Jurkat, Pas activation was followed by rapid loss of cell thiols, decreased mitochondrial membrane potential, increased [Ca2+](i) and increased PKC activity; all these responses were potentiated in LA pretreated cells. PKC delta played an important role in mediating the effect of LA on Pas-mediated cell death. In response to Pas activation LA treatment potentiated caspase 3 activation by over 100%. The ability of LA to potentiate Pas mediated killing of leukemic cells was abrogated by a caspase 3 inhibitor suggesting that increased caspase 3 activity in LA-treated Pas-activated cells played an important role in potentiating cell death. This work provides first evidence showing that inducible caspase 3 activity may be pharmacologically up regulated by reducing agents such as dihydrolipoic acid. C1 Univ Calif Berkeley, Dept Cell & Mol Biol, Berkeley, CA 94720 USA. Univ Kuopio, Dept Physiol, FIN-70211 Kuopio, Finland. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Sen, CK (reprint author), Univ Calif Berkeley, Dept Cell & Mol Biol, 251 Life Sci Addit, Berkeley, CA 94720 USA. RI Sen, Chandan/A-8762-2013 FU NIGMS NIH HHS [GM27345] NR 40 TC 63 Z9 64 U1 0 U2 0 PU STOCKTON PRESS PI BASINGSTOKE PA HOUNDMILLS, BASINGSTOKE RG21 6XS, HAMPSHIRE, ENGLAND SN 1350-9047 J9 CELL DEATH DIFFER JI Cell Death Differ. PD MAY PY 1999 VL 6 IS 5 BP 481 EP 491 DI 10.1038/sj.cdd.4400514 PG 11 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 195VH UT WOS:000080272500013 PM 10381641 ER PT J AU Kriesel, JW Tilley, TD AF Kriesel, JW Tilley, TD TI Dendrimers as building blocks for nanostructured materials: Micro- and mesoporosity in dendrimer-based xerogels SO CHEMISTRY OF MATERIALS LA English DT Article ID ORGANIC-INORGANIC MATERIALS; STATE NMR-SPECTROSCOPY; MASS-SPECTROMETRY; GELS; ALKOXYSILANES; COMPLEXES; CHEMISTRY; AEROGELS; SIZE AB Second and third generation silylalkoxy-terminated carbosilane dendrimers have been used to make high surface area xerogels via an acid-catalyzed sol-gel protocol. These xerogels are micro- and mesoporous and contain a high degree of -OH functionality. An unexpected xerogel surface area is described. These xerogels may have applications as (for example) catalyst supports and porous membranes. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Tilley, TD (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 40 TC 44 Z9 45 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD MAY PY 1999 VL 11 IS 5 BP 1190 EP + DI 10.1021/cm990058g PG 5 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 197YL UT WOS:000080394100006 ER PT J AU Lu, YF Cao, GZ Kale, RP Prabakar, S Lopez, GP Brinker, CJ AF Lu, YF Cao, GZ Kale, RP Prabakar, S Lopez, GP Brinker, CJ TI Microporous silica prepared by organic templating: Relationship between the molecular template and pore structure SO CHEMISTRY OF MATERIALS LA English DT Article ID INORGANIC MEMBRANES; KINETICS; POROSITY; REACTORS; GELS AB Microporous silica materials with a controlled pore size and a narrow pore size distribution have been prepared by sol-gel processing using an organic-templating approach. Microporous networks were formed by pyrolytic removal of organic ligands (methacryloxypropyl groups) from organic/inorganic hybrid materials synthesized by copolymerization of 3-methacryloxypropylsilane (MPS) and tetraethoxysilane (TEOS). Molecular simulations and experimental measurements were conducted to examine the relationship between the microstructural characteristics of the porous silica (e.g., pore size, total pore volume, and pore connectivity) and the size and amount of organic template ligands added. Adsorption measurements suggest that the final porosity of the microporous silica is due to both primary pores (those present in the hybrid material prior to pyrolysis) and secondary pores (those created by pyrolytic removal of organic templates). Primary pores were inaccessible to N-2 at 77 K but accessible to CO2 at 195 K; secondary pores were accessible to both N-2 (at 77 K) and CO2 (at 195 K) in adsorption measurements. Primary porosity decreases with the amount of organic ligands added because of the enhanced densification of MPS/TEOS hybrid materials as the mole fraction of trifunctional MPS moieties increases. Pore volumes measured by nitrogen adsorption experiments at 77 K suggest that the secondary (template-derived) porosity exhibits a percolation behavior as the template concentration is increased. Gas permeation experiments indicate that the secondary pores are approximately 5 Angstrom in diameter, consistent with predictions based on molecular simulations. C1 Univ New Mexico, Dept Chem & Nucl Engn, Ctr Microengn Mat, Albuquerque, NM 87131 USA. Sandia Natl Labs, Direct Fabricat Dept 1831, Albuquerque, NM 87131 USA. RP Lopez, GP (reprint author), Univ New Mexico, Dept Chem & Nucl Engn, Ctr Microengn Mat, Albuquerque, NM 87131 USA. RI Cao, Guozhong/E-4799-2011 NR 26 TC 79 Z9 79 U1 2 U2 17 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD MAY PY 1999 VL 11 IS 5 BP 1223 EP 1229 DI 10.1021/cm980517y PG 7 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 197YL UT WOS:000080394100011 ER PT J AU Li, DQ Ma, M AF Li, DQ Ma, M TI Nanosponges: From inclusion chemistry to water purifying technology SO CHEMTECH LA English DT Article ID INDUCED CIRCULAR-DICHROISM; ULTRA-PURE WATER; BETA-CYCLODEXTRIN; REVERSE-OSMOSIS; DRINKING-WATER; PURIFICATION; DERIVATIVES; COMPLEXES; BENZENES; SPECTRA C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Li, DQ (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Mail Stop G755,CST-4,POB 1663, Los Alamos, NM 87545 USA. NR 25 TC 22 Z9 22 U1 0 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0009-2703 J9 CHEMTECH JI Chemtech PD MAY PY 1999 VL 29 IS 5 BP 31 EP 37 PG 7 WC Chemistry, Applied SC Chemistry GA 195LX UT WOS:000080253300007 ER PT J AU Folland, CK Miller, C Bader, D Crowe, M Jones, P Plummer, N Richman, M Parker, DE Rogers, J Scholefield, P AF Folland, CK Miller, C Bader, D Crowe, M Jones, P Plummer, N Richman, M Parker, DE Rogers, J Scholefield, P TI Workshop on Indices and Indicators for Climate Extremes, Asheville, NC, USA, 3-6 June 1997 - Breakout Group C: Temperature indices for climate extremes SO CLIMATIC CHANGE LA English DT Article; Proceedings Paper CT Workshop on Indices and Indicators for Climate Extremes CY JUN 03-06, 1997 CL ASHEVILLE, NORTH CAROLINA SP CLIVAR, GCOS, WMO ID MINIMUM TEMPERATURE; TRENDS; VARIABILITY; INDEXES; MAXIMUM AB The "temperature" breakout group at the 1997 Asheville Workshop on Indicators and Indices for Climate Extremes reviewed and developed the rationale for a choice of temperature indices for monitoring changes in climate extremes, and the supporting data required. A set of basic and supplementary key indices was drawn up. The key indices are meant to be easy to interpret, be relevant to the practical concerns of policy makers and others in the public sector and provide potential inputs into the Third Assessment Review of the Intergovernmental Panel on Climate Change that is expected to report in 2001. The indices are expressed in various ways to facilitate spatial and temporal trend detection and impact analysis. There is flexibility in the number and the form of the indices identified and the choice for any particular application is subject to further analysis and prioritization. The success of this endeavor will depend on original work being done to further develop the indices and on the cooperation of organizations globally to provide the data necessary for the development and the implementation of the indices. This paper summarizes the group's recommendations. C1 Meteorol Off, Hadley Ctr, Bracknell RG12 2SY, Berks, England. NOAA,NESDIS,E EI, Silver Spring, MD 20910 USA. Pacific NW Natl Lab, Washington, DC 20024 USA. NOAA,NCDC, Asheville, NC 28801 USA. Univ E Anglia, Climat Res Unit, Norwich NR4 7TJ, Norfolk, England. Bur Meteorol, Natl Climat Ctr, Melbourne, Vic 3001, Australia. Univ Oklahoma, CIMMS, Norman, OK 73019 USA. Ohio State Univ, Dept Geog, Columbus, OH 43210 USA. WMO, World Climate Data & Monitoring Programme, Geneva 2, Switzerland. RP Folland, CK (reprint author), Meteorol Off, Hadley Ctr, Bracknell RG12 2SY, Berks, England. RI Jones, Philip/C-8718-2009; Bader, David/H-6189-2011; Folland, Chris/I-2524-2013 OI Jones, Philip/0000-0001-5032-5493; Bader, David/0000-0003-3210-339X; NR 22 TC 57 Z9 61 U1 0 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD MAY PY 1999 VL 42 IS 1 BP 31 EP 43 DI 10.1023/A:1005447712757 PG 13 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 236JQ UT WOS:000082596800005 ER PT J AU Zerkle, DK AF Zerkle, DK TI Phase segregation effects on the calculation of ODTX in HMX spheres SO COMBUSTION AND FLAME LA English DT Article C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Chem React Kinet & Dynam Grp, Los Alamos, NM 87545 USA. RP Zerkle, DK (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Chem React Kinet & Dynam Grp, POB 1663, Los Alamos, NM 87545 USA. NR 8 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD MAY PY 1999 VL 117 IS 3 BP 657 EP 659 DI 10.1016/S0010-2180(98)00130-8 PG 3 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 167XJ UT WOS:000078659900016 ER PT J AU White, DA AF White, DA TI Solution of capacitance systems using incomplete Cholesky fixed point iteration SO COMMUNICATIONS IN NUMERICAL METHODS IN ENGINEERING LA English DT Article DE finite element; electromagnetics; linear systems; iterative methods AB Application of the Galerkin finite element method to the electromagnetic vector wave equation yields an implicit system of equations that must be evolved in time. The left-hand matrix has units of capacitance and is analogous to the mass matrix in continuum mechanics. In this letter we point out the interesting fact that for a Cartesian grid the Cholesky decomposition of the capacitance matrix has the same sparsity as the original matrix, i.e. there is no zero-fill during the course of the Cholesky decomposition. Therefore an iterative method using the incomplete Cholesky decomposition as a preconditioner is quite efficient for nearly orthogonal quadrilateral or hexahedral grids. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Univ Calif Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, Livermore, CA 94551 USA. RP White, DA (reprint author), Univ Calif Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, MS L-560,POB 808, Livermore, CA 94551 USA. NR 4 TC 2 Z9 2 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 1069-8299 J9 COMMUN NUMER METH EN JI Commun. Numer. Methods Eng. PD MAY PY 1999 VL 15 IS 5 BP 375 EP 380 PG 6 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA 199WQ UT WOS:000080507400007 ER PT J AU Gauldie, RW Romanek, CR AF Gauldie, RW Romanek, CR TI Orange roughy otolith growth rates: a direct experimental test of the Romanek-Gauldie otolith growth model (vol 120, pg 649, 1998) SO COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR AND INTEGRATIVE PHYSIOLOGY LA English DT Correction C1 Univ Georgia, Savannah River Ecol Lab, Aiken, SC USA. RP Gauldie, RW (reprint author), 76 Inglis St, Wellington, New Zealand. NR 1 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 1095-6433 J9 COMP BIOCHEM PHYS A JI Comp. Biochem. Physiol. A-Mol. Integr. Physiol. PD MAY PY 1999 VL 123 IS 1 BP 111 EP 112 DI 10.1016/S1095-6433(99)00066-5 PG 2 WC Biochemistry & Molecular Biology; Physiology; Zoology SC Biochemistry & Molecular Biology; Physiology; Zoology GA 211LW UT WOS:000081163400013 ER PT J AU Boyle, JM Resler, RA Winter, VL AF Boyle, JM Resler, RA Winter, VL TI Do you trust your compiler? SO COMPUTER LA English DT Article AB As our society becomes more technologically complex, computer systems are finding an alarming number of uses in safety-critical applications. In many such systems, the software component's reliability is essential to the system's safe operation, so it becomes natural to ask, "How can software be made to behave correctly when executed?" Using Program transformations to produce trusted software simplifies verification. Program transformations use proven laws to manipulate programs in a manner analogous to algebraic transformations. The authors have sketched how a formal method based on program transformations can be used to construct a verified compiler. Such a compiler has been proved to correctly compile any correct program into assembly language. While the compiler itself may not execute efficiently-after all, you need only use the verified compiler the last time you compile a program-the transformational approach should enable the verified compiler to produce efficient assembly code. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Virginia Commonwealth Univ, Richmond, VA USA. Sandia Natl Labs, Livermore, CA 94550 USA. RP Boyle, JM (reprint author), Argonne Natl Lab, Argonne, IL 60439 USA. NR 10 TC 5 Z9 6 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 0018-9162 J9 COMPUTER JI Computer PD MAY PY 1999 VL 32 IS 5 BP 65 EP + DI 10.1109/2.762804 PG 10 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering SC Computer Science GA 193FY UT WOS:000080126300016 ER PT J AU Sternberg, M Galli, G Frauenheim, T AF Sternberg, M Galli, G Frauenheim, T TI NOON - a non-orthogonal localised orbital order-N method SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article ID ELECTRONIC-STRUCTURE CALCULATIONS; DENSITY-FUNCTIONAL CALCULATIONS; MOLECULAR-DYNAMICS; SIMULATIONS AB We present the implementation of an orbital-based linear scaling method for total energy calculations within a Tight-Binding approach. Our scheme explicitly incorporates charge self-consistency for both single- and multiple-species systems and uses non-orthogonal basis sets to construct non-orthogonal orbitals. The energy functional of Kim et al, [Phys. Rev. B 52 (1995) 1640] is minimised within a hierarchical iteration scheme for wave functions and the Lagrangian parameter. A number of Safeguard mechanisms are applied to stabilise the algorithms on both levels. Compared to exact diagonalisations using extended states we reproduce the total energy typically within 100 meV when localizing wave functions within second neighbours and within 30 meV when including third neighbours. The charge transfer effects and related energies for self-consistent-charge corrections are reproduced accurately. (C) 1999 Elsevier Science B.V. C1 Univ Gesamthsch Paderborn, Dept Phys, D-33098 Paderborn, Germany. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. RP Sternberg, M (reprint author), Univ Gesamthsch Paderborn, Dept Phys, D-33098 Paderborn, Germany. RI Frauenheim, Thomas/C-5653-2015 OI Frauenheim, Thomas/0000-0002-3073-0616 NR 12 TC 14 Z9 14 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD MAY PY 1999 VL 118 IS 2-3 BP 200 EP 212 DI 10.1016/S0010-4655(99)00202-7 PG 13 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 205GV UT WOS:000080813700009 ER PT J AU Coriano, C Savkli, C AF Coriano, C Savkli, C TI QCD evolution equations: numerical algorithms from the Laguerre expansion SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article DE parton distribution; evolution; Altarelli-Parisi ID PARTON DISTRIBUTIONS; DRELL-YAN; SPIN; SCATTERING AB A complete numerical implementation, in both singlet and nonsinglet sectors, of a very elegant method to solve the QCD Evolution equations, due to Furmanski and Petronzio, is presented. The algorithm is directly implemented in x-space by a Laguerre expansion of the parton distributions. All the leading-twist distributions are evolved: longitudinally polarized, transversely polarized and unpolarized, to NLO accuracy. The expansion is optimal at finite x, up to reasonably small x-values (x approximate to 10(-3)), below which the convergence of the expansion slows down. The polarized evolution is smoother, due to the less singular structure of the polarized DGLAP kernels at small-x. In the region of fast convergence, which covers most of the usual perturbative applications, high numerical accuracy is achieved by expanding over a set of approximately 30 polynomials, with a very modest running time. (C) 1999 Published by Elsevier Science B.V. C1 Jefferson Lab, Theory Grp, Newport News, VA 23606 USA. Coll William & Mary, Dept Phys, Williamsburg, VA 23187 USA. RP Coriano, C (reprint author), Jefferson Lab, Theory Grp, Newport News, VA 23606 USA. OI Coriano', Claudio/0000-0003-0479-8075 NR 28 TC 21 Z9 21 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD MAY PY 1999 VL 118 IS 2-3 BP 236 EP 258 DI 10.1016/S0010-4655(98)00158-1 PG 23 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 205GV UT WOS:000080813700012 ER PT J AU Castillo, JE Otto, JS AF Castillo, JE Otto, JS TI A practical guide to direct optimization for planar grid-generation SO COMPUTERS & MATHEMATICS WITH APPLICATIONS LA English DT Article DE variational grid-generation; length functional; folding; alignment; vector field ID EQUATIONS AB In this paper, we provide a guide to using the direct optimization formulation of variational grid-generation. Particular emphasis is placed on the smoothness, or length, functional; this is undoubtedly the most important functional in variational grid-generation, producing smooth grids and ensuring well-posedness of the minimization problem when combined with more unruly Functionals. Unfortunately, in its most primary form, length can produce folded grids when used with nonconvex geometries. Historically, there have been two solutions to this dilemma: using an inverse mapping (the famous Winslow generator), or augmenting the functional with others that promote unicity. Both strategies have the drawback that the resulting minimization problem becomes complicated and expensive. As another alternative, we introduce a generalized strategy for length which does not use inverse mappings or auxiliary functionals, but makes strong use of reference grids. This strategy provides flexibility in controlling grid quality, and its minimization problems can be solved using a simple multigrid algorithm, yielding a robust grid-generation scheme with optimal complexity. We also survey recent developments in the use of variational grid-generation (in the form of direct optimization) for the alignment problem. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ New Mexico, Dept Comp Sci, Albuquerque, NM 87131 USA. RP Castillo, JE (reprint author), Sandia Natl Labs, Org 9223,MS 1110, Albuquerque, NM 87185 USA. NR 31 TC 8 Z9 9 U1 1 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0898-1221 J9 COMPUT MATH APPL JI Comput. Math. Appl. PD MAY PY 1999 VL 37 IS 9 BP 123 EP 156 DI 10.1016/S0898-1221(99)00118-2 PG 34 WC Mathematics, Applied SC Mathematics GA 191GB UT WOS:000080013200012 ER PT J AU Plum, CA Wilson, AK Bhattacharyya, MH AF Plum, CA Wilson, AK Bhattacharyya, MH TI A nest box to facilitate excreta collection from mouse dams through pregnancy, parturition, and lactation SO CONTEMPORARY TOPICS IN LABORATORY ANIMAL SCIENCE LA English DT Article ID RATS AB Standard metabolism cages are inadequate for collecting excreta from dams during parturition because newborn pups can fall through the grating into the excreta collection area and out of reach of the dam. A nest box was designed that facilitates excreta collection from mouse dams continuously housed in metabolism cages from conception, through parturition, and into lactation and provides a safe, warm environment for pups during their first week of life. The nest box was tested by using pregnant and lactating mice of two varieties of strain 129/SvJ, metallothionein-normal and metallothionein-knockout; non-pregnant mice were used as controls. Pregnant mice (with nest box) and non-pregnant mice (without nest box) each twice received a solution of (CdCl2)-Cd-109 by gavage, Dams with nest boxes fastidiously urinated and defecated outside the nest box. The percentage of gavage Cd-109 dose recovered in dam feces was the same after the first gavage (mean+/-SE, with nest box through parturition, 95%+/-6%; n=5) as after the second gavage (mean+/-SE, without nest box, 95%+/-6%; n=5), Weights and percentage weight gain of mouse dams were independent of housing conditions (metabolic cage with next box vs, conventional polycarbonate caging). Furthermore, pup growth and survival were unaffected by the inclusion of the nest box or by its removal at 1 week after birth. Therefore, the described nest box provides for the first time a way to quantitatively collect excreta from mouse dams through pregnancy, parturition, and the early postnatal period. Additional experiments are needed to test its application to other animal species and strains of mice, including those with poor mothering behavior. C1 Oregon State Univ, Dept Toxicol, Corvallis, OR 97331 USA. Benedictine Univ, Dept Biol Sci, Lisle, IL 60532 USA. Argonne Natl Lab, Div Biosci, Argonne, IL 60439 USA. RP Plum, CA (reprint author), Oregon State Univ, Dept Toxicol, Corvallis, OR 97331 USA. NR 15 TC 0 Z9 0 U1 0 U2 0 PU AMER ASSOC LABORATORY ANIMAL SCIENCE PI MEMPHIS PA 9190 CRESTWYN HILLS DR, MEMPHIS, TN 38125 USA SN 1060-0558 J9 CONTEMP TOP LAB ANIM JI Contemp. Top. Lab. Anim. Sci. PD MAY PY 1999 VL 38 IS 3 BP 71 EP 77 PG 7 WC Veterinary Sciences; Zoology SC Veterinary Sciences; Zoology GA 198MJ UT WOS:000080427700005 ER PT J AU Putirka, K AF Putirka, K TI Clinopyroxene plus liquid equilibria to 100 kbar and 2450 K SO CONTRIBUTIONS TO MINERALOGY AND PETROLOGY LA English DT Article ID MIDOCEAN RIDGE BASALT; SILICATE MELTS; EXPERIMENTAL PETROLOGY; PHASE-RELATIONS; TRACE-ELEMENTS; PRESSURE; PERIDOTITE; PYROXENE; GLASSES; MANTLE AB One of the most active issues in igneous petrology is the investigation of mantle melting, and subsequent differentiation. To evaluate alternative hypotheses for melting and differentiation it is essential to accurately predict clinopyroxene compositions in natural systems. Expressions have thus been derived that describe clinopyroxene-melt equilibria, and allow equilibrium clinopyroxene compositions to be calculated. These equations were constructed from least-squares regression analysis of experimental clinopyroxene-liquid pairs. The calibration database included clinopyroxenes synthesized from both natural and synthetic basalt compositions; experimental conditions ranged from 0 to 100 kbar and 1350 to 2450 K. Regression equations were based on thermodynamic functions. Empirical expressions were also derived, since such models yield more precise estimates of clinopyroxene compositions, and may be easily incorporated into existing liquid line-of-descent models. Such equations may be useful for calculation of high pressure liquid fractionation, or for constraining P-T conditions for basalts produced by partial melting of a pyroxene-bearing source. Models of mantle melting often rely on expressions involving simple element ratios. Partition coefficients (K-d(cpx/liq)) for the minor elements, Na and Ti, were thus also calibrated as a function of P, T and composition. K-Ti(cpx/liq), while sensitive to composition was relatively insensitive to P and T. In constrast, K-Na(cpx/liq) increases substantially with increasing. P, and exceeded 1 in some experiments. Since oceanic basalts show variations in Na/Ti ratios, the potential exists for partial melting depths to be inferred from K-Na(cpx/liq). C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Putirka, K (reprint author), Univ Calif Lawrence Livermore Natl Lab, L-202,700 E Ave, Livermore, CA 94550 USA. NR 56 TC 90 Z9 92 U1 1 U2 18 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0010-7999 J9 CONTRIB MINERAL PETR JI Contrib. Mineral. Petrol. PD MAY PY 1999 VL 135 IS 2-3 BP 151 EP 163 DI 10.1007/s004100050503 PG 13 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA 200VA UT WOS:000080559700004 ER PT J AU Fujita, E AF Fujita, E TI Photochemical carbon dioxide reduction with metal complexes SO COORDINATION CHEMISTRY REVIEWS LA English DT Article; Proceedings Paper CT XXXIII International Conference on Coordination Chemistry CY AUG 30-SEP 04, 1998 CL FLORENCE, ITALY DE carbon dioxide reduction; small molecule activation; photocatalysis; carboxylates; macrocycles; diimine ID VISIBLE-LIGHT IRRADIATION; PORPHYRIN-CATALYZED REDUCTION; CO2 REDUCTION; ELECTROCATALYTIC REDUCTION; ELECTROCHEMICAL REDUCTION; HOMOGENEOUS CATALYSTS; PHOTOSENSITIZED REDUCTION; PHOTOINDUCED REDUCTION; COBALT MACROCYCLES; COORDINATION MODE AB Transition-metal complexes, CoHMD2+ (HMD = 5,7,7, 12,14,14-hexametethyl-1,4,8, 11-tetraazacyclotetradeca-4, Il-diene) and Ru(bpy)(2)(CO)Xn+ (bpy = 2,2'-bipyridine, X = CO, Cl, H, etc.), mediate electron transfer in the photochemical reduction of CO2. The thermodynamics and kinetics of CO2 binding to CoHMD+, and spectroscopic characterization of the CO2 adducts of CoHMD+ and [Ru-I(bpy)(bpy(-))(CO)] are described. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Fujita, E (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. EM fujita@bnl.gov RI Fujita, Etsuko/D-8814-2013 NR 57 TC 148 Z9 150 U1 9 U2 115 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0010-8545 J9 COORDIN CHEM REV JI Coord. Chem. Rev. PD MAY PY 1999 VL 185-6 BP 373 EP 384 DI 10.1016/S0010-8545(99)00023-5 PG 12 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 203GX UT WOS:000080701200023 ER PT J AU Fish, RH AF Fish, RH TI Bioorganometallic chemistry: synthesis, structure, and molecular recognition chemistry of (eta(5)-pentamethylcyclopentadienyl)-rhodium-DNA/RNA complexes in water SO COORDINATION CHEMISTRY REVIEWS LA English DT Article; Proceedings Paper CT XXXIII International Conference on Coordination Chemistry CY AUG 30-SEP 04, 1998 CL FLORENCE, ITALY DE Cp*Rh aqua complexes; Cp*Rh-DNA/RNA complexes; molecular recognition ID NONCOVALENT PI-PI; (ETA-5-PENTAMETHYLCYCLOPENTADIENYL)RHODIUM AQUA COMPLEX; AQUEOUS COORDINATION CHEMISTRY; BIOLOGICALLY IMPORTANT LIGANDS; METALLOCENE ANTITUMOR AGENTS; CARBOXYLIC-ACID GUESTS; AROMATIC AMINO-ACID; CYCLIC TRIMER HOSTS; METAL-COMPLEXES; ORGANOMETALLIC CHEMISTRY AB A review of the aqueous bioorganometallic chemisty of DNA/RNA nucleobases and of the co;factor, nicotinamide adenine dinucleotide, with an (eta(5)-pentamethylcyclopentadienyl)rhodium aqua complex, [Cp*Rh(H2O)(3)](OTf)(2), at various pH values, will be presented. The unique structures of the Cp*Rh complexes with adenine, guanine, cytosine, thymine, and nicotinamide adenine dinucleotide bioligands were determined by a combination of H-1- and P-31-NMR, ESI/MS, and single crystal X-ray crystallography. Competitive reactivity studies; principally with the more reactive adenine: and guanine derivatives, showed the important bonding characteristics with these nucleobases, while a novel cyclic trimer structure with 9-substituted adenine derivatives provided a new supramolecular receptor for molecular recognition studies with a variety of biologically important guests. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Fish, RH (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. EM rhfish@lbl.gov NR 33 TC 92 Z9 92 U1 1 U2 8 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0010-8545 J9 COORDIN CHEM REV JI Coord. Chem. Rev. PD MAY PY 1999 VL 185-6 BP 569 EP 584 DI 10.1016/S0010-8545(99)00011-9 PG 16 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 203GX UT WOS:000080701200032 ER PT J AU Rose, KA Rutherford, ES McDermot, DS Forney, JL Mills, EL AF Rose, KA Rutherford, ES McDermot, DS Forney, JL Mills, EL TI Individual-based model of yellow perch and walleye populations in Oneida Lake SO ECOLOGICAL MONOGRAPHS LA English DT Review DE compensation; density dependence; fish; individual-based; population dynamics; predator-prey; recruitment; simulation model; stability; walleye; yellow perch ID STIZOSTEDION-VITREUM-VITREUM; PREDATOR-PREY SYSTEMS; NEW-YORK; DENSITY-DEPENDENCE; FUNCTIONAL RESPONSE; FOOD-CONSUMPTION; LARVAL WALLEYES; HIGH MORTALITY; MARINE FISH; FLAVESCENS AB Predator-prey dynamics and density dependence are fundamental issues in ecology. We use a detailed, individual-based model of walleye and yellow perch to investigate the effects of alternative prey and compensatory responses on predator and prey population dynamics. Our analyses focus on the numerical and developmental responses of the predator, rather than the traditional emphasis on functional responses. The extensive database for Oneida Lake, New York, USA was used to configure the model and ensure its realism. The model follows the daily growth, mortality, and spawning of individuals of each species through their lifetime. Three ecologically distinct periods in the history of Oneida Lake were simulated: baseline, high mayfly densities, and high forage fish densities. Mayflies and forage fish act as alternative prey for walleye. For model corroboration, the three periods were simulated sequentially as they occurred in Oneida Lake. Model predictions of abundances, size at age, and growth and survival rates compared favorably with Oneida Lake data. Three hypotheses suggested by the data were evaluated: alternative prey stabilizes yellow perch and walleye populations; alternative prey increases yellow perch and walleye recruitment; and density-dependent growth and survival compensate for changes in young-of-the-year mortality. Model simulations were performed under increased mayfly densities, increased forage fish densities, and increased egg mortality rates. Predicted recruitment and population stability depended on the magnitude of increased walleye prey and differed between mayflies and forage fish. Compensation was driven by density-dependent growth, resulting in younger age at maturation and increased fecundity. We compare our results using a detailed, size-structured model capable of numerical and developmental responses of predators to results from classical predator-prey theory. Weaknesses in the current version of the individual-based model and knowledge gaps that require additional empirical data collection are also discussed. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Univ Michigan, Fisheries Res Inst, Ann Arbor, MI 48109 USA. Univ Tennessee, Dept Ecol & Evolutionary Biol, Knoxville, TN 37796 USA. Cornell Univ, Biol Stn, Bridgeport, NY 13030 USA. RP Rose, KA (reprint author), Louisiana State Univ, Coastal Fisheries Inst, Wetlands Resources Bldg, Baton Rouge, LA 70803 USA. OI Rutherford, Edward/0000-0002-7282-6667 NR 101 TC 81 Z9 83 U1 1 U2 24 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 1990 M STREET NW, STE 700, WASHINGTON, DC 20036 USA SN 0012-9615 EI 1557-7015 J9 ECOL MONOGR JI Ecol. Monogr. PD MAY PY 1999 VL 69 IS 2 BP 127 EP 154 DI 10.1890/0012-9615(1999)069[0127:IBMOYP]2.0.CO;2 PG 28 WC Ecology SC Environmental Sciences & Ecology GA 194CY UT WOS:000080175600001 ER PT J AU Bhattacharya, RN Batchelor, W Noufi, RN AF Bhattacharya, RN Batchelor, W Noufi, RN TI Electroless deposition of Cu-In-Ga-Se thin films SO ELECTROCHEMICAL AND SOLID STATE LETTERS LA English DT Article AB Copper-indium-gallium-selenium thin films have been prepared by electroless deposition technique on an Mo/glass substrate. Electroless precursors are prepared by short-circuiting the Mo substrate to the Fe counter electrode. The films are characterized by inductively coupled plasma and X-ray analysis. The device fabricated using electroless precursor films resulted in a solar cell efficiency of 12.4%. (C) 1999 The Electrochemical Society. S1099-0062(98)12-082-5. All rights reserved. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Bhattacharya, RN (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. NR 7 TC 5 Z9 7 U1 1 U2 7 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 65 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 1099-0062 J9 ELECTROCHEM SOLID ST JI Electrochem. Solid State Lett. PD MAY PY 1999 VL 2 IS 5 BP 222 EP 223 DI 10.1149/1.1390790 PG 2 WC Electrochemistry; Materials Science, Multidisciplinary SC Electrochemistry; Materials Science GA 186UT UT WOS:000079749100006 ER PT J AU Sigalas, MM Biswas, R Ho, KM Leung, W Tuttle, G Crouch, DD AF Sigalas, MM Biswas, R Ho, KM Leung, W Tuttle, G Crouch, DD TI The effect of photonic crystals on dipole antennas SO ELECTROMAGNETICS LA English DT Article ID BAND-GAP CRYSTALS AB We study the radiation patterns of antennas placed on top and inside three dimensional photonic band-gap (PBG) materials. The Finite Difference Time Domain method has been used for the calculation of the radiation patterns. Measurements are in good agreement with theoretical results. The different factors influencing the patterns (position, height, and frequency) have been studied. C1 Iowa State Univ, Ames Lab, Ctr Microelect Res, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. Raytheon Corp, AET Ctr, Rancho Cucamonga, CA 91720 USA. RP Sigalas, MM (reprint author), Iowa State Univ, Ames Lab, Ctr Microelect Res, Ames, IA 50011 USA. NR 21 TC 5 Z9 5 U1 0 U2 1 PU HEMISPHERE PUBL CORP PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 USA SN 0272-6343 J9 ELECTROMAGNETICS JI Electromagnetics PD MAY-JUN PY 1999 VL 19 IS 3 BP 291 EP 303 DI 10.1080/02726349908908645 PG 13 WC Engineering, Electrical & Electronic SC Engineering GA 201KB UT WOS:000080593000006 ER PT J AU Turgeon, JL Van Patten, SM Shyamala, G Waring, DW AF Turgeon, JL Van Patten, SM Shyamala, G Waring, DW TI Steroid regulation of progesterone receptor expression in cultured rat gonadotropes SO ENDOCRINOLOGY LA English DT Article ID BREAST-CANCER-CELLS; LUTEINIZING-HORMONE SECRETION; MESSENGER-RIBONUCLEIC-ACID; PITUITARY-CELLS; ANTERIOR-PITUITARY; GENE-EXPRESSION; ESTROUS-CYCLE; TARGET TISSUES; IMMATURE RAT; FEMALE RAT AB During the preovulatory period. the pituitary action of progesterone is biphasic, moving from a severalfold augmentation of the gonadotropin release action of GnRH to a suppression of GnRH efficacy, which occurs in rats over a period of about 12 h, but the extent to which these biphasic effects are dependent on alterations in progesterone receptor (PR) expression is not known. To address this, as well as the localization of PR in cultured rat pituitary cells, we used cells from ovariectomized rats cultured +/- 0.2 nM E-2 with acute progesterone treatment on day 3. Northern blot of poly(A(+)) RNA extracts showed multiple PR messenger RNA (mRNA) transcripts between 4.8-10.2 kb; E-2 treatment led to a 5- to g-fold increase in the predominant PR mRNA, transcripts !5.1 and 110.1 kb. In the presence of E-2, 200 nM progesterone resulted in a decrease in steady-state PR mRNA levels by 3 h of exposure, with the greatest decrease around 6 h (50% of E-2, control) and recovery by 12 h. Similarly treated pituitary cultures were subjected to dual immunofluorescence staining for LH and PR. In the absence of E-2, PR was undetectable. In the presence of E-2 essentially all LH-positive cells were positive for PR and only 1-2% of PR-immunopositive cells were negative for LH, possibly reflecting FSH-exclusive gonadotropes, PR staining was predominantly nuclear, but 20 nM progesterone led to a gradual increase in cytoplasmic staining, with the nuclear-to-cytoplasmic ratio decreasing to near unity by 9-12 h of exposure. In summary, we show for the first time, that PR colocalizes with LH in cultured female rat pituitary cells and that E-2 induces expression of PR mRNA, as well as PR protein, in rat gonadotropes. In the presence of E-2, progesterone causes a rapid but transient down-regulation of PR message; recovery of PR mRNA is accompanied by an increase in cytoplasmic PR, suggestive of an increase in synthesis. These dynamic changes implicate the gonadotrope PR as having a significant role within the temporal context of the rat preovulatory period. C1 Univ Calif Davis, Sch Med, Dept Human Physiol, Davis, CA 95616 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP Turgeon, JL (reprint author), Univ Calif Davis, Sch Med, Dept Human Physiol, Davis, CA 95616 USA. EM jlturgeon@ucdavis.edu FU NCI NIH HHS [CA-66541]; NICHD NIH HHS [HD-12137] NR 45 TC 31 Z9 31 U1 0 U2 0 PU ENDOCRINE SOC PI CHEVY CHASE PA 8401 CONNECTICUT AVE, SUITE 900, CHEVY CHASE, MD 20815-5817 USA SN 0013-7227 EI 1945-7170 J9 ENDOCRINOLOGY JI Endocrinology PD MAY PY 1999 VL 140 IS 5 BP 2318 EP 2325 DI 10.1210/en.140.5.2318 PG 8 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA 187RP UT WOS:000079801200044 PM 10218985 ER PT J AU Akbari, H Konopacki, S Pomerantz, M AF Akbari, H Konopacki, S Pomerantz, M TI Cooling energy savings potential of reflective roofs for residential and commercial buildings in the United States SO ENERGY LA English DT Article ID URBAN HEAT ISLANDS AB We make quantitative estimates of the impact of roof reflectivity on cooling and heating energy use for buildings in the US. Prototypical buildings are simulated with reflective (light in color) and absorptive (dark in color) roofs. Differences of annual cooling and heating energy use and peak electricity demand between dark and light roofs yield the savings. The DOE-2 building energy simulation program is used for these calculations. Monetary savings are calculated using local utility rates. Savings are estimated for 11 US metropolitan statistical areas (MSAs) in a variety of climates. The total savings for all 11 MSAs are: annual electricity savings, 2.6 terawatt hours (TWh); net annual savings, $194 M; and peak electricity demand savings, 1.7 gigawatt (GW), Extrapolating the savings from the 11 MSAs to the entire United States, we estimate annual electricity savings of about 10 TWh and a net savings of about $750 M in annual energy payments. Peak electricity power reduction is estimated to be about 7 GW. Published by Elsevier Science Ltd. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Heat Isl Grp, Berkeley, CA 94720 USA. RP Akbari, H (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Heat Isl Grp, Berkeley, CA 94720 USA. NR 20 TC 81 Z9 85 U1 1 U2 21 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0360-5442 J9 ENERGY JI Energy PD MAY PY 1999 VL 24 IS 5 BP 391 EP 407 DI 10.1016/S0360-5442(98)00105-4 PG 17 WC Thermodynamics; Energy & Fuels SC Thermodynamics; Energy & Fuels GA 194TJ UT WOS:000080209400003 ER PT J AU Rothenberger, KS Cugini, AV Thompson, RL Pugmire, RJ Solum, MS AF Rothenberger, KS Cugini, AV Thompson, RL Pugmire, RJ Solum, MS TI Polyolefin degradation in a continuous coal liquefaction reactor SO ENERGY & FUELS LA English DT Article ID WASTE PLASTICS; POLYETHYLENE; CRACKING; MODEL AB A novel solvent extraction method to isolate and recover polyolefin materials from coal-plastics coprocessing product streams is reported. The method was applied to samples obtained from a bench-scale continuous unit, coprocessing coal with polyethylene (PE), polypropylene (PP), and polystyrene (PS) feed. Recovered PE and PP have been characterized by infrared (IR) and nuclear magnetic resonance (NMR) spectroscopies, and gel permeation chromatography (GPC); PS is completely converted to distillable product. The results indicate that PP undergoes fairly rapid and essentially quantitative reaction and its conversion is complete before reaching the downstream portion of the process. On the other hand, PE undergoes some degradation in the coal liquefaction reactor, with an average reduction in molecular weight distribution for the "unconverted" material by a factor of 10 to 30. GPC can definitively distinguish between fresh (feed) and recycled PE in the process stream and has established that most of the PE degradation occurs in the first-stage liquefaction reactor. This partially converted, but undistillable material then passes into the atmospheric still bottoms stream. The two solid separation methods examined had very different effects on the incompletely reacted PE. Vacuum distillation sequesters the PE in the unconvertable (ashy) fraction, whereas pressure filtration allows most of it to pass through into the recycle stream. A qualitative mechanism for PE breakdown is proposed in which rapid scission occurs at the branching points of the paraffin backbone, followed by eventual breakdown to distillable products. C1 US DOE, Fed Energy Technol Ctr, Pittsburgh, PA 15236 USA. Parsons Infrastruct & Technol Grp Inc, Library, PA 15129 USA. Univ Utah, Dept Chem & Fuels Engn, Salt Lake City, UT 84112 USA. RP Rothenberger, KS (reprint author), US DOE, Fed Energy Technol Ctr, POB 10940, Pittsburgh, PA 15236 USA. NR 18 TC 0 Z9 0 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0887-0624 J9 ENERG FUEL JI Energy Fuels PD MAY-JUN PY 1999 VL 13 IS 3 BP 710 EP 718 DI 10.1021/ef980230n PG 9 WC Energy & Fuels; Engineering, Chemical SC Energy & Fuels; Engineering GA 197YD UT WOS:000080393200022 ER PT J AU Damste, JSS White, CM Green, JB de Leeuw, JW AF Damste, JSS White, CM Green, JB de Leeuw, JW TI Organosulfur compounds in sulfur-rich Rasa coal SO ENERGY & FUELS LA English DT Article ID PYROLYSIS-GAS CHROMATOGRAPHY; ORGANICALLY-BOUND SULFUR; FLASH PYROLYSIS; GEOCHEMICAL SIGNIFICANCE; ARTIFICIAL MATURATION; MOLECULAR CHARACTERIZATION; AROMATIC-HYDROCARBONS; HEAVY PETROLEUM; FOSSIL-FUELS; FORMS AB The organosulfur compounds in the extract and pyrolysate of the unusually organic sulfur-rich (11.4 wt %) Upper Palaeocene Rasa coal have been identified by gas chromatography-high-resolution mass spectrometry. The major organosulfur compounds (OSC) present in the extract are alkylated benzo[b]- and dibenzothiophenes and in the pyrolysates alkylated thiophenes and benzo[b]thiophenes. In addition, a large suite of sulfur-containing polyaromatics were identified, which sometimes contain more than one sulfur atom per molecule. The degree of alkylation of many homologous series was found to maximize at either three, four, or five alkyl carbons. The dominance of polyaromatic sulfur compounds is consistent with the relatively mature stage of the coal (R-o approximate to 0.7%), and their abundance at this rank indicates that the initial peat must have been extremely organic sulfur-rich (atomic S-org/C ratio approximate to 0.15). This together with the very low abundance of lignin-derived components in the coal pyrolysate indicates that Rasa coal should not be considered a typical coal. Nevertheless, our results represent a starting point that can be used as a guide for analysis of other coals. C1 Univ Utrecht, Inst Earth Sci, Dept Geochem, NL-3508 TA Utrecht, Netherlands. Netherlands Inst Sea Res, Dept Marine Biogeochem & Toxicol, NL-1790 AB Den Burg, Netherlands. Fed Energy Technol Ctr, Pittsburgh, PA 15236 USA. BDM Petr Technol, Bartlesville, OK 74005 USA. RP Damste, JSS (reprint author), Univ Utrecht, Inst Earth Sci, Dept Geochem, POB 80021, NL-3508 TA Utrecht, Netherlands. RI de Leeuw, Jan/F-6471-2011; Sinninghe Damste, Jaap/F-6128-2011 OI Sinninghe Damste, Jaap/0000-0002-8683-1854 NR 57 TC 33 Z9 33 U1 0 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0887-0624 J9 ENERG FUEL JI Energy Fuels PD MAY-JUN PY 1999 VL 13 IS 3 BP 728 EP 738 PG 11 WC Energy & Fuels; Engineering, Chemical SC Energy & Fuels; Engineering GA 197YD UT WOS:000080393200024 ER PT J AU Daisey, JM AF Daisey, JM TI Tracers for assessing exposure to environmental tobacco smoke: What are they tracing? SO ENVIRONMENTAL HEALTH PERSPECTIVES LA English DT Article; Proceedings Paper CT Workshop on Environmental Tobacco Smoke Exposure Assessment CY SEP 12-13, 1997 CL BALTIMORE, MARYLAND DE complex mixture; environmental tobacco smoke; exposure; indoor air quality; nicotine; semivolatile organic compounds; sorption; volatile organic compounds ID VOLATILE ORGANIC-COMPOUNDS; POLYCYCLIC AROMATIC-HYDROCARBONS; INDOOR AIR; EMISSION FACTORS; CHEMICAL-COMPOSITION; NICOTINE; SEMIVOLATILE; VENTILATION; CONVECTION; DESORPTION AB The effectiveness of various tracers for measurements of exposure to environmental tobacco smoke (ETS) as a complex chemical mixture is based on the physicochemical properties of four major organic components and their dynamic behavior in indoor environments. For the particulate matter (PM) component and the very volatile organic compounds, emission and ventilation rates are generally the most important processes controlling indoor concentrations and exposures of nonsmokers. For the volatile organic compounds (VOCs) and semivolatile organic compounds (SVOCs), sorption on and desorption from indoor surfaces are additional processes that influence exposures. Laboratory and modeling studies of the dynamic behavior of nicotine, an SVOC, and PM indicate that nicotine can be used to estimate PM exposures from ETS in indoor environments when certain criteria are met: a) smoking occurs regularly in the environment, b) the system is near quasi-steady state, and c) sampling time is longer than the characteristic times for removal processes. Measurements in residential and workplace buildings also support the use of nicotine as a tracer for PM in ETS. Recent laboratory and field data indicate that the VOCs from ETS can be traced using compounds with similar physicochemical properties, such as 3-ethenylpyridine, pyrrole, or pyridine. The effectiveness of nicotine for estimating exposures to the VOCs and SVOCs has not been determined, although these constitute major mass fractions of ETS. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Environ Energy Technol Div, Indoor Environm Dept, Berkeley, CA 94720 USA. RP Daisey, JM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Environ Energy Technol Div, Indoor Environm Dept, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 59 TC 55 Z9 57 U1 4 U2 17 PU US DEPT HEALTH HUMAN SCIENCES PUBLIC HEALTH SCIENCE PI RES TRIANGLE PK PA NATL INST HEALTH, NATL INST ENVIRONMENTAL HEALTH SCIENCES, PO BOX 12233, RES TRIANGLE PK, NC 27709-2233 USA SN 0091-6765 J9 ENVIRON HEALTH PERSP JI Environ. Health Perspect. PD MAY PY 1999 VL 107 SU 2 BP 319 EP 327 DI 10.2307/3434424 PG 9 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA 195YK UT WOS:000080280000016 PM 10350517 ER PT J AU Jenkins, RA Counts, RW AF Jenkins, RA Counts, RW TI Occupational exposure to environmental tobacco smoke: Results of two personal exposure studies SO ENVIRONMENTAL HEALTH PERSPECTIVES LA English DT Article; Proceedings Paper CT Workshop on Environmental Tobacco Smoke Exposure Assessment CY SEP 12-13, 1997 CL BALTIMORE, MARYLAND DE area sampling; environmental tobacco smoke; ETS; exposure; nicotine; personal monitoring; solanesol ID INDOOR ENVIRONMENTS; WORKPLACE AB Personal monitoring is a more accurate measure of individual exposure to airborne constituents because it incorporates human activity patterns and collects actual breathing zone samples to which subjects are exposed. Two recent studies conducted by our laboratory offer perspective on occupational exposure to environmental tobacco smoke (ETS) from a personal exposure standpoint. In a study of nearly 1600 workers, levels of ETS were lower than or comparable to those in earlier studies. Limits on smoking in designated areas also acted to reduce overall exposure of workers. In facilities where smoking is permitted, ETS exposures are 10 to 20 times greater than in facilities in which smoking is banned. Service workers were exposed to higher levels of ETS than workers in white-collar occupations. For the narrower occupational category of waiters, waitresses, and bartenders, a second study in one urban location indicated that ETS levels to which wait staff are exposed are not considerably different from those exposure levels of subjects in the larger study who work in environments in which smoking is unrestricted. Bartenders were exposed to higher ETS levels, but there is a distinction between bartenders working in smaller facilities and those working in multiroom restaurant bars, with the former exposed to higher levels of ETS than the latter. in addition, ETS levels encountered by these more highly exposed workers are lower that those estimated by the Occupational Safety and Health Administration. Concomitant area monitoring in the smaller study suggests that area samples can only be used to estimate individual personal exposure to within an order of magnitude or greater. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Comp Sci & Math, Oak Ridge, TN 37831 USA. RP Jenkins, RA (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, POB 2008,MS 6120,Bldg 4500S,Bethel Valley Rd,X-10, Oak Ridge, TN 37831 USA. NR 19 TC 38 Z9 40 U1 0 U2 2 PU US DEPT HEALTH HUMAN SCIENCES PUBLIC HEALTH SCIENCE PI RES TRIANGLE PK PA NATL INST HEALTH, NATL INST ENVIRONMENTAL HEALTH SCIENCES, PO BOX 12233, RES TRIANGLE PK, NC 27709-2233 USA SN 0091-6765 J9 ENVIRON HEALTH PERSP JI Environ. Health Perspect. PD MAY PY 1999 VL 107 SU 2 BP 341 EP 348 DI 10.2307/3434426 PG 8 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA 195YK UT WOS:000080280000018 PM 10350519 ER PT J AU Salk, MS Tolbert, VR Dickerman, JA AF Salk, MS Tolbert, VR Dickerman, JA TI Guidelines and techniques for improving the NEPA process SO ENVIRONMENTAL MANAGEMENT LA English DT Article ID SCIENCE AB The Council on Environmental Quality's (CEQ's) principal aims in implementing the National Environmental Policy Act (NEPA) are (I)to reduce paperwork, (2) to avoid delay and most importantly (3) to produce better decisions that protect, restore, and enhance the environment. This paper presents lour strategies for improving the NEPA process along with tools that can be used to implement each strategy. The tools include guidelines for project management and problem definition, tips for acquiring existing information and identifying issues of public concern, worksheets on how to identify and analyze potential impacts on resources, ideas for enhancing NEPA documents, and a NEPA process checklist. The tools can be used at various stages of the NEPA process and provide a toolbox of guidelines and techniques to improve implementation of the NEPA process by focusing the pertinent information for decisionmakers and stakeholders. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Salk, MS (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008,MS-6036, Oak Ridge, TN 37831 USA. NR 22 TC 1 Z9 1 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0364-152X J9 ENVIRON MANAGE JI Environ. Manage. PD MAY PY 1999 VL 23 IS 4 BP 467 EP 476 DI 10.1007/s002679900201 PG 10 WC Environmental Sciences SC Environmental Sciences & Ecology GA 180JQ UT WOS:000079382800005 ER PT J AU Dahlgran, J AF Dahlgran, J TI Performance evaluation soil samples for volatile organic compounds utilizing solvent encapsulation technology SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article AB A mixture of volatile organic compounds (VOCs) was encapsulated and mixed with a soil to produce a product suitable for use as a double blind source of VOCs in a soil performance evaluation sample. Two independent laboratories analyzed the standard encapsulated VOC/soil mixture for benzene, toluene, ethylbenzene, and xylene by using U.S. EPA SW-846 Method 5035 in conjunction with SW-846 Method 8020. One laboratory received the sample as a single blind standard, while the other laboratory received the sample as a double blind standard. The percent relative standard deviation (%RSD) for triplicate analyses ranged from 2 to 13%. The lowest %RSD was for m/p-xylene (2%) from the sample analyzed as a double blind sample. Analytical results from these pilot studies indicate that it is possible to prepare standard soil samples contaminated with known amounts of VOCs which will enable soil samples to be submitted to environmental analytical laboratories as a truly blind sample. C1 US Dept Energy, Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83401 USA. Thies Technol, St Louis, MO 63401 USA. RP Dahlgran, J (reprint author), US Dept Energy, Idaho Natl Engn & Environm Lab, 850 Energy Dr,MS 4149, Idaho Falls, ID 83401 USA. NR 8 TC 1 Z9 1 U1 1 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD MAY 1 PY 1999 VL 33 IS 9 BP 1534 EP 1537 DI 10.1021/es9807845 PG 4 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 192YH UT WOS:000080107000048 ER PT J AU Johnson, MS Franke, LS Lee, RB Holladay, SD AF Johnson, MS Franke, LS Lee, RB Holladay, SD TI Bioaccumulation of 2,4,6-trinitrotoluene and polychlorinated biphenyls through two routes of exposure in a terrestrial amphibian: Is the dermal route significant? SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE salamander; dermal; 2,4,6-trinitrotoluene; bioaccumulation; Ambystoma tigrinum ID SALAMANDER AB Tiger salamanders (Ambystoma tigrinum) were exposed via soil and/or food (earthworms) to 2,4,6-trinitrotoluene (TNT) and a PCB mixture (Aroclor 1260) at environmentally relevant concentrations. Four exposures were considered: (1) uncontaminated food + uncontaminated soil (control group); (2) contaminated soil + uncontaminated food (dermal group); (3) contaminated food + uncontaminated soil (oral group); and, (4) contaminated soil + contaminated food (dual-exposure group). The chemical exposure was estimated for each group by analysis of both soil and earthworms. Body burdens of TNT and its primary metabolites were highest in the dermal groups while PCB burdens were highest in the oral groups. Concentrations of the primary TNT metabolites evaluated, 2-amino-dinitrotoluene (DNT) and 4-amino-DNT, exceeded that of unmetabolized TNT and accumulated to 116 and 670 ng/g, respectively. These results provide evidence that dermal exposures to nitroaromatics in terrestrial salamanders may make an important contribution to total body burden and thus may be important when considering the health consequences of such exposures. Further, the demonstration of the accumulation of TNT and TNT metabolites in a primitive vertebrate may have food web modeling implications. C1 Oak Ridge Inst Sci & Educ, Oak Ridge, TN 37831 USA. DAKKRO Corp, Littleton, CO 80161 USA. Virginia Tech, Virginia Maryland Reg Coll Vet Med, Blacksburg, VA 24061 USA. RP Johnson, MS (reprint author), USA, Ctr Hlth Promot & Prevent Med, Toxicol Directorate, 5158 Blackhawk Rd, Aberdeen Proving Ground, MD 21010 USA. NR 32 TC 34 Z9 34 U1 0 U2 9 PU SETAC PRESS PI PENSACOLA PA 1010 NORTH 12TH AVE, PENSACOLA, FL 32501-3370 USA SN 0730-7268 J9 ENVIRON TOXICOL CHEM JI Environ. Toxicol. Chem. PD MAY PY 1999 VL 18 IS 5 BP 873 EP 878 DI 10.1897/1551-5028(1999)018<0873:BOTAPB>2.3.CO;2 PG 6 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 187RQ UT WOS:000079801300009 ER PT J AU Zywicz, E AF Zywicz, E TI On the equivalence of stress- and strain-based failure criteria in Elastic Media SO EUROPEAN JOURNAL OF MECHANICS A-SOLIDS LA English DT Article DE failure criteria; fiber direction ID TENSOR AB Conditions for which strain-based and stress-based failure criteria are mathematically equivalent in elastic media are explored by expressing the criteria in the spectral eigenspace of the elasticity tensor. For scalar-valued quadratic criteria that are homogeneous functions of degree one, stress-based and strain-based criteria are most likely to be mathematically equivalent when the criteria's operators are linear combinations of the elasticity's spectral eigenbasis tensors. For the commonly employed fiber-direction sb:ain-based and fiber-direction stress-based "composite" failure criteria, the equivalence conditions are explicitly examined for orthotropic and transversely isotropic material symmetry. The difference between the two criteria decreases as the degree of extensional anisotropy increases but, in general, is unbounded for arbitrary deformation states. Over a moderate, but restricted, range of loading conditions, the difference between the criteria is small for high-modulus fiber-reinforced uni-directional lamina, often less than the uncertainties in either the elastic coefficients or failure values, and the two criteria appear interchangeable. (C) Elsevier, Paris. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Zywicz, E (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94550 USA. NR 7 TC 1 Z9 1 U1 0 U2 1 PU GAUTHIER-VILLARS/EDITIONS ELSEVIER PI PARIS PA 23 RUE LINOIS, 75015 PARIS, FRANCE SN 0997-7538 J9 EUR J MECH A-SOLID JI Eur. J. Mech. A-Solids PD MAY-JUN PY 1999 VL 18 IS 3 BP 391 EP 398 DI 10.1016/S0997-7538(99)00129-1 PG 8 WC Mechanics SC Mechanics GA 222KE UT WOS:000081783000002 ER PT J AU Batchelder, JC Toth, KS Bingham, CR Brown, LT Conticchio, LF Davids, CN Irvine, RJ Seweryniak, D Walters, WB Wauters, J Zganjar, EF Wood, JL DeCoster, C Decroix, B Heyde, K AF Batchelder, JC Toth, KS Bingham, CR Brown, LT Conticchio, LF Davids, CN Irvine, RJ Seweryniak, D Walters, WB Wauters, J Zganjar, EF Wood, JL DeCoster, C Decroix, B Heyde, K TI Behavior of intruder based states in light Bi and Tl isotopes: the study of Bi-187 alpha decay SO EUROPEAN PHYSICAL JOURNAL A LA English DT Article ID MASS NUCLEI; ODD-MASS; COEXISTENCE AB The excitation energies of the single-particle normal and intruder levels in both Tl-183 and Bi-187 were measured for the first time via the alpha decay of Bi-187 produced in the Mo-97(Mo-92,pn)Bi-187 reaction. The previously unobserved Bi-187 ground state (h(g/2)) to Tl-183 ground state (s(1/2)) alpha transition was identified, establishing the Bi-187 intruder state excitation energy to be 112(21) keV, 70 keV less than that of the same level in Bi-189. C1 Oak Ridge Associated Univ, UNIRIB, Oak Ridge, TN 37831 USA. Louisiana State Univ, Baton Rouge, LA 70803 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Tennessee, Knoxville, TN 37996 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Vanderbilt Univ, Nashville, TN 37235 USA. Univ Maryland, College Pk, MD 20742 USA. Univ Edinburgh, Edinburgh EH9 3JZ, Midlothian, Scotland. Georgia Inst Technol, Atlanta, GA 30332 USA. Inst Theoret Phys, B-9000 Ghent, Belgium. Inst Nucl Phys, B-9000 Ghent, Belgium. RP Batchelder, JC (reprint author), Oak Ridge Associated Univ, UNIRIB, Oak Ridge, TN 37831 USA. NR 13 TC 22 Z9 22 U1 0 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1434-6001 J9 EUR PHYS J A JI Eur. Phys. J. A PD MAY PY 1999 VL 5 IS 1 BP 49 EP 52 DI 10.1007/s100500050255 PG 4 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 200KD UT WOS:000080538100008 ER PT J AU Breitweg, J Derrick, M Krakauer, D Magill, S Mikunas, D Musgrave, B Repond, J Stanek, R Talaga, RL Yoshida, R Zhang, H Mattingly, MCK Anselmo, F Antonioli, P Bari, G Basile, M Bellagamba, L Boscherini, D Bruni, A Bruni, G Romeo, CG Castellini, G Cifarelli, L Cindolo, F Contin, A Coppola, N Corradi, M De Pasquale, S Giusti, P Iacobucci, G Laurenti, G Levi, G Margotti, A Massam, T Nania, R Palmonari, F Pesci, A Polini, A Sartorelli, G Garcia, YZ Zichichi, A Amelung, C Bornheim, A Brock, I Coboken, K Crittenden, J Deffner, R Eckert, M Grothe, M Hartmann, H Heinloth, K Heinz, L Hilger, E Jakob, HP Kappes, A Katz, UF Kerger, R Paul, E Pfeiffer, M Stamm, J Wedemeyer, R Wieber, H Bailey, DS Campbell-Robson, S Cottingham, WN Foster, B Hall-Wilton, R Heath, GP Heath, HF McFall, JD Piccioni, D Roff, DG Tapper, RJ Ayad, R Capua, M Garfagnini, A Iannotti, L Schioppa, M Susinno, G Kim, JY Lee, JH Lim, IT Pac, MY Caldwell, A Cartiglia, N Jing, Z Liu, W Mellado, B Parsons, JA Ritz, S Sampson, S Sciulli, F Straub, PB Zhu, Q Borzemski, P Chwastowski, J Eskreys, A Figiel, J Klimek, K Przybycien, MB Zawiejski, L Adamczyk, L Bednarek, B Bukowy, M Czermak, AM Jelen, K Kisielewska, D Kowalski, T Przybycien, M Rulikowska-Zarebska, E Suszycki, L Zajac, J Dulinski, Z Kotanski, A Abbiendi, G Bauerdick, LAT Behrens, U Beier, H Bienlein, JK Cases, G Desler, K Drews, G F'ricke, U Gialas, I Goebel, F Gottlicher, P Graciani, R Haas, T Hain, W Hasell, D Hebbel, K Johnson, KF Kasemann, M Koch, W Kotz, U Kowalski, H Lindemann, L Lohr, B Milewski, J Monteiro, T Ng, JST Notz, D Park, IH Pellegrino, A Pelucchi, F Piotrzkowski, K Rohde, M Roldan, J Ryan, JJ Savin, AA Schneekloth, U Schwarzer, O Selonke, F Stonjek, S Surrow, B Tassi, E Westphal, D Wolf, G Wollmer, U Youngman, C Zeuner, W Burow, BD Coldewey, C Grabosch, HJ Meyer, A Schlenstedt, S Barbagli, G Gallo, E Pelfer, P Maccarrone, G Votano, L Bamberger, A Eisenhardt, S Markun, P Raach, H Trefzger, T Wolfle, S Bromley, JT Brook, NH Bussey, PJ Doyle, AT Macdonald, N Saxon, DH Sinclair, LE Strickland, E Waugh, R Bohnet, I Gendner, N Holm, U Meyer-Larsen, A Salehi, H Wick, K Gladilin, LK Horstmann, D Kcira, D Klanner, R Lohrmann, E Poelz, G Schott, W Zetsche, F Bacon, TC Butterworth, I Cole, JE Howell, G Lamberti, L Long, KR Miller, DB Pavel, N Prinias, A Sedgbeer, JK Sideris, D Walker, R Mallik, U Wang, SM Wu, JT Cloth, P Filges, D Fleck, JI Ishii, T Kuze, M Suzuki, I Tokushuku, K Yamada, S Yamauchi, K Yamazaki, Y Hong, SJ Lee, SB Nam, SW Park, SK Barreiro, F Fernandez, JP Garcia, G Glasman, C Hernandez, JM Hervas, L Labarga, L Martinez, M del Peso, J Puga, J Terron, J de Troconiz, JF Corriveau, F Hanna, DS Hartmann, J Hung, LW Murray, WN Ochs, A Riveline, M Stairs, DG St-Laurent, M Ullmann, R Tsurugai, T Bashkirov, V Dolgoshein, BA Stifutkin, A Bashindzhagyan, GL Ermolov, PF Golubkov, YA Khein, LA Korotkova, NA Krozhavina, IA Kuzmin, VA Lukina, OY Proskuryakov, AS Shcheglova, LM Solomin, AN Zotkin, SA Bokel, C Botje, M Brummer, N Engelen, J Koffeman, E Kooijman, P van Sighem, A Tiecke, H Tuning, N Verkerke, W Vossebeld, J Wiggers, L de Wolf, E Acosta, D Bylsma, B Durkin, LS Gilmore, J Ginsburg, CM Kim, CL Ling, TY Nylander, P Romanowski, TA Blaikley, HE Cashmore, RJ Cooper-Sarkar, AM Devenish, RCE Edmonds, JK Grosse-Knetter, J Harnew, N Nath, C Noyes, VA Quadt, A Ruske, O Tickner, JR Uijterwaal, H Walczak, R Waters, DS Bertolin, A Brugnera, R Carlin, R Dal Corso, F Dosselli, U Limentani, S Morandin, M Posocco, M Stanco, L Stroili, R Voci, C Bulmahn, J Oh, BY Okrasinski, JR Toothacker, WS Whitmore, JJ Iga, Y D'Agostini, G Marini, G Nigro, A Raso, M Hart, JC McCubbin, NA Shah, TP Epperson, D Heusch, C Rahn, JT Sadrozinski, HFW Seiden, A Wichmann, R Williams, DC Abramowicz, H Briskin, G Dagan, S Kananov, S Levy, A Abe, T Fusayasu, T Inuzuka, M Nagano, K Umemori, K Yamashita, T Hamatsu, R Hirose, T Homma, K Kitamura, S Matsushita, T Arneodo, M Cirio, R Costa, M Ferrero, MI Maselli, S Monaco, V Peroni, C Petrucci, MC Ruspa, M Sacchi, R Solano, A Staiano, A Dardo, M Bailey, DC Fagerstroem, CP Galea, R Hartner, GF Joo, KK Levman, GM Martin, JF Orr, RS Polenz, S Sabetfakhri, A Simmons, D Teuscher, RJ Butterworth, JM Catterall, CD Hayes, ME Jones, TW Lane, J Saunders, RL Sutton, MR Wing, M Ciborowski, J Grzelak, G Kasprzak, M Nowak, RJ Pawlak, JM Pawlak, R Tymieniecka, T Wroblewski, AK Zakrzewski, JA Zarnecki, AF Adamus, M Deppe, O Eisenberg, Y Hochman, D Karshon, U Badgett, WF Chapin, D Cross, R Dasu, S Foudas, C Loveless, RJ Mattingly, S Reeder, DD Smith, WH Vaiciulis, A Wodarczyk, M Deshpande, A Dhawan, S Hughes, VW Bhadra, S Frisken, WR Khakzad, M Schmidke, WB AF Breitweg, J Derrick, M Krakauer, D Magill, S Mikunas, D Musgrave, B Repond, J Stanek, R Talaga, RL Yoshida, R Zhang, H Mattingly, MCK Anselmo, F Antonioli, P Bari, G Basile, M Bellagamba, L Boscherini, D Bruni, A Bruni, G Romeo, CG Castellini, G Cifarelli, L Cindolo, F Contin, A Coppola, N Corradi, M De Pasquale, S Giusti, P Iacobucci, G Laurenti, G Levi, G Margotti, A Massam, T Nania, R Palmonari, F Pesci, A Polini, A Sartorelli, G Garcia, YZ Zichichi, A Amelung, C Bornheim, A Brock, I Coboken, K Crittenden, J Deffner, R Eckert, M Grothe, M Hartmann, H Heinloth, K Heinz, L Hilger, E Jakob, HP Kappes, A Katz, UF Kerger, R Paul, E Pfeiffer, M Stamm, J Wedemeyer, R Wieber, H Bailey, DS Campbell-Robson, S Cottingham, WN Foster, B Hall-Wilton, R Heath, GP Heath, HF McFall, JD Piccioni, D Roff, DG Tapper, RJ Ayad, R Capua, M Garfagnini, A Iannotti, L Schioppa, M Susinno, G Kim, JY Lee, JH Lim, IT Pac, MY Caldwell, A Cartiglia, N Jing, Z Liu, W Mellado, B Parsons, JA Ritz, S Sampson, S Sciulli, F Straub, PB Zhu, Q Borzemski, P Chwastowski, J Eskreys, A Figiel, J Klimek, K Przybycien, MB Zawiejski, L Adamczyk, L Bednarek, B Bukowy, M Czermak, AM Jelen, K Kisielewska, D Kowalski, T Przybycien, M Rulikowska-Zarebska, E Suszycki, L Zajac, J Dulinski, Z Kotanski, A Abbiendi, G Bauerdick, LAT Behrens, U Beier, H Bienlein, JK Cases, G Desler, K Drews, G F'ricke, U Gialas, I Goebel, F Gottlicher, P Graciani, R Haas, T Hain, W Hasell, D Hebbel, K Johnson, KF Kasemann, M Koch, W Kotz, U Kowalski, H Lindemann, L Lohr, B Milewski, J Monteiro, T Ng, JST Notz, D Park, IH Pellegrino, A Pelucchi, F Piotrzkowski, K Rohde, M Roldan, J Ryan, JJ Savin, AA Schneekloth, U Schwarzer, O Selonke, F Stonjek, S Surrow, B Tassi, E Westphal, D Wolf, G Wollmer, U Youngman, C Zeuner, W Burow, BD Coldewey, C Grabosch, HJ Meyer, A Schlenstedt, S Barbagli, G Gallo, E Pelfer, P Maccarrone, G Votano, L Bamberger, A Eisenhardt, S Markun, P Raach, H Trefzger, T Wolfle, S Bromley, JT Brook, NH Bussey, PJ Doyle, AT Macdonald, N Saxon, DH Sinclair, LE Strickland, E Waugh, R Bohnet, I Gendner, N Holm, U Meyer-Larsen, A Salehi, H Wick, K Gladilin, LK Horstmann, D Kcira, D Klanner, R Lohrmann, E Poelz, G Schott, W Zetsche, F Bacon, TC Butterworth, I Cole, JE Howell, G Lamberti, L Long, KR Miller, DB Pavel, N Prinias, A Sedgbeer, JK Sideris, D Walker, R Mallik, U Wang, SM Wu, JT Cloth, P Filges, D Fleck, JI Ishii, T Kuze, M Suzuki, I Tokushuku, K Yamada, S Yamauchi, K Yamazaki, Y Hong, SJ Lee, SB Nam, SW Park, SK Barreiro, F Fernandez, JP Garcia, G Glasman, C Hernandez, JM Hervas, L Labarga, L Martinez, M del Peso, J Puga, J Terron, J de Troconiz, JF Corriveau, F Hanna, DS Hartmann, J Hung, LW Murray, WN Ochs, A Riveline, M Stairs, DG St-Laurent, M Ullmann, R Tsurugai, T Bashkirov, V Dolgoshein, BA Stifutkin, A Bashindzhagyan, GL Ermolov, PF Golubkov, YA Khein, LA Korotkova, NA Krozhavina, IA Kuzmin, VA Lukina, OY Proskuryakov, AS Shcheglova, LM Solomin, AN Zotkin, SA Bokel, C Botje, M Brummer, N Engelen, J Koffeman, E Kooijman, P van Sighem, A Tiecke, H Tuning, N Verkerke, W Vossebeld, J Wiggers, L de Wolf, E Acosta, D Bylsma, B Durkin, LS Gilmore, J Ginsburg, CM Kim, CL Ling, TY Nylander, P Romanowski, TA Blaikley, HE Cashmore, RJ Cooper-Sarkar, AM Devenish, RCE Edmonds, JK Grosse-Knetter, J Harnew, N Nath, C Noyes, VA Quadt, A Ruske, O Tickner, JR Uijterwaal, H Walczak, R Waters, DS Bertolin, A Brugnera, R Carlin, R Dal Corso, F Dosselli, U Limentani, S Morandin, M Posocco, M Stanco, L Stroili, R Voci, C Bulmahn, J Oh, BY Okrasinski, JR Toothacker, WS Whitmore, JJ Iga, Y D'Agostini, G Marini, G Nigro, A Raso, M Hart, JC McCubbin, NA Shah, TP Epperson, D Heusch, C Rahn, JT Sadrozinski, HFW Seiden, A Wichmann, R Williams, DC Abramowicz, H Briskin, G Dagan, S Kananov, S Levy, A Abe, T Fusayasu, T Inuzuka, M Nagano, K Umemori, K Yamashita, T Hamatsu, R Hirose, T Homma, K Kitamura, S Matsushita, T Arneodo, M Cirio, R Costa, M Ferrero, MI Maselli, S Monaco, V Peroni, C Petrucci, MC Ruspa, M Sacchi, R Solano, A Staiano, A Dardo, M Bailey, DC Fagerstroem, CP Galea, R Hartner, GF Joo, KK Levman, GM Martin, JF Orr, RS Polenz, S Sabetfakhri, A Simmons, D Teuscher, RJ Butterworth, JM Catterall, CD Hayes, ME Jones, TW Lane, J Saunders, RL Sutton, MR Wing, M Ciborowski, J Grzelak, G Kasprzak, M Nowak, RJ Pawlak, JM Pawlak, R Tymieniecka, T Wroblewski, AK Zakrzewski, JA Zarnecki, AF Adamus, M Deppe, O Eisenberg, Y Hochman, D Karshon, U Badgett, WF Chapin, D Cross, R Dasu, S Foudas, C Loveless, RJ Mattingly, S Reeder, DD Smith, WH Vaiciulis, A Wodarczyk, M Deshpande, A Dhawan, S Hughes, VW Bhadra, S Frisken, WR Khakzad, M Schmidke, WB CA ZEUS Collaboration TI Measurement of jet shapes in high-Q(2) deep inelastic scattering at HERA SO EUROPEAN PHYSICAL JOURNAL C LA English DT Article ID P(P)OVER-BAR COLLISIONS; CROSS-SECTIONS; PARTON DISTRIBUTIONS; HADRON COLLIDERS; 3-JET EVENTS; QCD CASCADES; EP; PHOTOPRODUCTION; QUARK; TEV AB The shapes of jets with transverse energies, E(T)(jet), up to 45 GeV produced in neutral- and charged-current deep inelastic e(+)p scattering (DIS) at Q(2) > 100 GeV(2) have been measured with the ZEUS detector at HERA. Jets are identified using a cane algorithm in the eta-phi plane with a cone radius of one unit. The jets become narrower as E(T)(jet) increases. The jet, shapes in neutral- and charged-current DIS are found to be very similar. The jets in neutral-current DIS are narrower than those in resolved processes in photoproduction and closer to those in direct-photon processes for the same ranges in E(T)(jet) and jet pseudorapidity. The jet shapes in DIS are observed to be similar to those in e(+)e(-) interactions and narrower than those in (p) over bar p collisions for comparable E(T)(jet). Since the jets in e(+)e(-) interactions and e(+)p DIS are predominantly quark initiated in both cases, the similarity in the jet shapes indicates that the pattern of QCD radiation within a quark jet is to a large extent independent of the hard scattering process in these reactions. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Andrews Univ, Berrien Springs, MI 49104 USA. Univ Bologna, Bologna, Italy. Ist Nazl Fis Nucl, I-40126 Bologna, Italy. Univ Bonn, Inst Phys, D-5300 Bonn, Germany. Univ Bristol, HH Wills Phys Lab, Bristol BS8 1TL, Avon, England. Univ Calabria, Dept Phys, I-87036 Cosenza, Italy. Ist Nazl Fis Nucl, I-87036 Cosenza, Italy. Chonnam Natl Univ, Kwangju 500757, South Korea. Columbia Univ, Nevis Labs, Irvington, NY USA. Inst Nucl Phys, Krakow, Poland. Acad Min & Met Cracow, Fac Phys & Nucl Tech, Krakow, Poland. Jagiellonian Univ, Dept Phys, Krakow, Poland. DESY, D-2000 Hamburg, Germany. DESY, IfH, Zeuthen, Germany. Univ Florence, Florence, Italy. Ist Nazl Fis Nucl, I-50125 Florence, Italy. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Univ Freiburg, Fak Phys, D-7800 Freiburg, Germany. Univ Glasgow, Dept Phys & Astron, Glasgow, Lanark, Scotland. Univ Hamburg, Inst Expt Phys 1, Hamburg, Germany. Univ Hamburg, Inst Expt Phys 2, D-2000 Hamburg, Germany. Univ London Imperial Coll Sci Technol & Med, High Energy Nucl Phys Grp, London, England. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. Forschungszentrum Julich, Inst Kernphys, D-5170 Julich, Germany. KEK, Inst Particle & Nucl Studies, Tsukuba, Ibaraki, Japan. Korea Univ, Seoul 136701, South Korea. Univ Autonoma Madrid, Dept Fis Teor, Madrid, Spain. McGill Univ, Dept Phys, Montreal, PQ, Canada. Meiji Gakuin Univ, Fac Gen Educ, Yokohama, Kanagawa, Japan. Moscow Phys Engn Inst, Moscow, Russia. Moscow MV Lomonosov State Univ, Inst Nucl Phys, Moscow, Russia. Univ Amsterdam, Amsterdam, Netherlands. NIKHEF, Amsterdam, Netherlands. Ohio State Univ, Dept Phys, Columbus, OH 43210 USA. Univ Oxford, Dept Phys, Oxford, England. Univ Padua, Dipartimento Fis, Padua, Italy. Ist Nazl Fis Nucl, Padua, Italy. Penn State Univ, Dept Phys, University Pk, PA 16802 USA. Polytech Univ, Sagamihara, Kanagawa, Japan. Univ Roma La Sapienza, Dipartimento Fis, I-00185 Rome, Italy. Ist Nazl Fis Nucl, Rome, Italy. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, Sch Phys, Tel Aviv, Israel. Univ Tokyo, Dept Phys, Tokyo 113, Japan. Tokyo Metropolitan Univ, Dept Phys, Tokyo, Japan. Ist Nazl Fis Nucl, I-10125 Turin, Italy. Univ Turin, Dipartimento Fis Sperimentale, Turin, Italy. Univ Turin, Fac Sci 2, Alessandria, Italy. Ist Nazl Fis Nucl, Alessandria, Italy. Univ Toronto, Dept Phys, Toronto, ON, Canada. UCL, Dept Phys & Astron, London, England. Univ Warsaw, Inst Expt Phys, Warsaw, Poland. Inst Nucl Studies, PL-00681 Warsaw, Poland. Weizmann Inst Sci, Dept Particle Phys, IL-76100 Rehovot, Israel. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Yale Univ, Dept Phys, New Haven, CT USA. York Univ, Dept Phys, N York, ON M3J 1P3, Canada. IROE, Florence, Italy. RP Breitweg, J (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Solomin, Anatoly/C-3072-2016; Graciani Diaz, Ricardo/I-5152-2016; Capua, Marcella/A-8549-2015; Gladilin, Leonid/B-5226-2011; De Pasquale, Salvatore/B-9165-2008; Wing, Matthew/C-2169-2008; Bashkirov, Vladimir/A-4818-2008; Doyle, Anthony/C-5889-2009; Golubkov, Yury/E-1643-2012; Proskuryakov, Alexander/J-6166-2012; Katz, Uli/E-1925-2013; Wiggers, Leo/B-5218-2015; Hernandez Calama, Jose Maria/H-9127-2015; Tassi, Enrico/K-3958-2015; Morandin, Mauro/A-3308-2016 OI Graciani Diaz, Ricardo/0000-0001-7166-5198; Castellini, Guido/0000-0002-0177-0643; Capua, Marcella/0000-0002-2443-6525; Arneodo, Michele/0000-0002-7790-7132; Abbiendi, Giovanni/0000-0003-4499-7562; Gladilin, Leonid/0000-0001-9422-8636; De Pasquale, Salvatore/0000-0001-9236-0748; Doyle, Anthony/0000-0001-6322-6195; Katz, Uli/0000-0002-7063-4418; Wiggers, Leo/0000-0003-1060-0520; Hernandez Calama, Jose Maria/0000-0001-6436-7547; Morandin, Mauro/0000-0003-4708-4240 NR 56 TC 25 Z9 25 U1 0 U2 4 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1434-6044 J9 EUR PHYS J C JI Eur. Phys. J. C PD MAY PY 1999 VL 8 IS 3 BP 367 EP 380 DI 10.1007/s100520050471 PG 14 WC Physics, Particles & Fields SC Physics GA 203AP UT WOS:000080685100001 ER PT J AU Huang, T Jin, HY Zhang, AL AF Huang, T Jin, HY Zhang, AL TI The masses of the 0(++) and 0(-+) light-quark hybrids using QCD sum rules SO EUROPEAN PHYSICAL JOURNAL C LA English DT Article ID EXOTIC MESONS; HERMAPHRODITE MESONS; BAG MODEL; JPC =1-+; STATES AB We calculate the masses of the light-quark hybrid mesons with the quantum numbers 0(++) and 0(-+) by using the QCD sum rules. Two kinds of interpolated currents with the same quantum numbers are employed. We find that approximately equal masses are predicted for the 0(++) hybrid state using the different currents, and different masses are obtained for the 0(++) hybrid state using the different currents. The prediction depends on the interaction between the gluon and the quarks in the low-lying hybrid mesons. The mixing effect on the mass of the light-quark hybrid mesons through the low-energy theorem has also been examined, and it is found that this mixing shifts the masses of the hybrid mesons and the glueball a little. C1 CCAST, World Lab, Beijing 100080, Peoples R China. Inst High Energy Phys, Beijing 100039, Peoples R China. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Huang, T (reprint author), CCAST, World Lab, POB 8730, Beijing 100080, Peoples R China. NR 24 TC 7 Z9 7 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1434-6044 J9 EUR PHYS J C JI Eur. Phys. J. C PD MAY PY 1999 VL 8 IS 3 BP 465 EP 471 PG 7 WC Physics, Particles & Fields SC Physics GA 203AP UT WOS:000080685100010 ER PT J AU Fitzgerald, M Picard, RR Silver, RN AF Fitzgerald, M Picard, RR Silver, RN TI Canonical transition probabilities for adaptive Metropolis stimulation SO EUROPHYSICS LETTERS LA English DT Article ID MONTE-CARLO METHOD; FREE-ENERGY; PHASE-TRANSITIONS; SPIN-GLASS; SIMULATIONS; ALGORITHMS AB We examine non-Boltzmann Monte Carlo algorithms used to study slowly relaxing systems. By adding a simple bookkeeping step to the Metropolis algorithm, we obtain statistical estimators of canonical macrostate probabilities. These estimators enable a natural accumulation of statistics from simulations having different importance weights, enable temperature extrapolation without using energy to define macrostate labels, improve parallelization, and reduce variance. We illustrate with an Ising model example. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Fitzgerald, M (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 24 TC 88 Z9 88 U1 2 U2 5 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0295-5075 J9 EUROPHYS LETT JI Europhys. Lett. PD MAY 1 PY 1999 VL 46 IS 3 BP 282 EP 287 DI 10.1209/epl/i1999-00257-1 PG 6 WC Physics, Multidisciplinary SC Physics GA 194ZY UT WOS:000080225700002 ER PT J AU Tanaka, TJ AF Tanaka, TJ TI Measurements of the effects of smoke on active circuits SO FIRE AND MATERIALS LA English DT Article AB Smoke has long been recognized as the most common source of fire damage to electrical equipment; however, most failures have been analysed after the fire was out and the smoke vented. The effects caused while the smoke is still in the air have not been explored. Such effects have implications for new digital equipment being installed in nuclear reactors. The US Nuclear Regulatory Commission is sponsoring work to determine the impact of smoke on digital instrumentation and control. As part of this programme, Sandia National Laboratories has tested simple active circuits to determine how smoke affects them. These tests included the study of three possible failure modes on a functional board: (1) circuit bridging, (2) corrosion (metal loss), and (3) induction of stray capacitance. The performance of nine different circuits was measured continuously on bare and conformally coated boards during smoke exposures lasting 1 h each and continued for 24 h after the exposure started, The circuit that was most affected by smoke (100% change in measured values) was the one most sensitive to circuit bridging. Its high impedance (50 M Omega) was shorted during the exposure, but in some cases recovered after the smoke was vented, The other two failure modes, corrosion and induced stray capacitance, caused little change in the function of the circuits. The smoke permanently increased resistance, of the circuit tested for corrosion, implying that the contacts were corroded. However, the change was very small (< 2%). The stray-capacitance test circuit showed very little change after a smoke exposure in either the short or long term. The results of the tests suggest that conformal coatings and type of circuit are major considerations when designing digital circuitry to be used in critical control systems. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Sandia Natl Labs, Accid & Consequence Anal Dept, Albuquerque, NM 87185 USA. RP Tanaka, TJ (reprint author), Sandia Natl Labs, Accid & Consequence Anal Dept, POB 5800, Albuquerque, NM 87185 USA. NR 13 TC 3 Z9 3 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0308-0501 J9 FIRE MATER JI Fire Mater. PD MAY-JUN PY 1999 VL 23 IS 3 BP 103 EP 108 DI 10.1002/(SICI)1099-1018(199905/06)23:3<103::AID-FAM670>3.0.CO;2-P PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA 241GD UT WOS:000082873500001 ER PT J AU Hwang, CK Hong, BG Swain, D AF Hwang, CK Hong, BG Swain, D TI Fast sweep of current phases in ICH antenna straps SO FUSION ENGINEERING AND DESIGN LA English DT Article DE ICRF heating; KSTAR; ICRF antenna; fast sweep of phases; tuning method AB Ion cyclotron (IC) system for KSTAR (Korean Superconducting Tokamak Advanced Research) tokamak has been designed to be capable of fast sweeping the phase intervals of the antenna strap currents with all the mechanical tuners fixed. It is shown that the fast sweep is possible by use of proper decoupler circuits. Design and tuning method for the decoupler circuit are described. We show that the circuit works satisfactorily by examining its behavior under the fast sweep. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Korea Atom Energy Res Inst, Taejon 305600, South Korea. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Hong, BG (reprint author), Korea Atom Energy Res Inst, POB 105, Taejon 305600, South Korea. NR 4 TC 9 Z9 9 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0920-3796 J9 FUSION ENG DES JI Fusion Eng. Des. PD MAY PY 1999 VL 45 IS 2 BP 127 EP 135 DI 10.1016/S0920-3796(99)00003-4 PG 9 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 212PB UT WOS:000081224500001 ER PT J AU MacLaren, DC Gambhir, SS Satyamurthy, N Barrio, JR Sharfstein, S Toyokuni, T Wu, L Berk, AJ Cherry, SR Phelps, ME Herschman, HR AF MacLaren, DC Gambhir, SS Satyamurthy, N Barrio, JR Sharfstein, S Toyokuni, T Wu, L Berk, AJ Cherry, SR Phelps, ME Herschman, HR TI Repetitive, non-invasive imaging of the dopamine D-2 receptor as a reporter gene in living animals SO GENE THERAPY LA English DT Article DE reporter gene; dopamine receptor; positron emission tomography ID POSITRON-EMISSION-TOMOGRAPHY; VIRUS THYMIDINE KINASE; ADENOVIRUS-MEDIATED TRANSFER; CONSERVED SERINE RESIDUES; IN-VITRO; MAMMALIAN-CELLS; TRANSGENIC MICE; EXPRESSION; THERAPY; PET AB Reporter genes (eg beta-galactosiclase, chloramphenicol-acetyltransferase, green fluorescent protein, luciferase)play roles in investigating mechanisms of gene expression in transgenic animals and in developing gene delivery systems for gene therapy However, measuring expression of these reporter genes requires biopsy or death. We now report a procedure to image reporter gene expression repetitively and non-invasively in living animals with positron emission tomography (PET)I using the dopamine type 2 receptor (D2R) as a reporter gene and 3-(2'[18F]fluoroethyl)spiperone (FESP) as a reporter probe. We use a viral delivery system to demonstrate the ability of this PET reporter gene/PET reporter probe system to image repoter gene expression following somatic:gene transfer. in mice injected intravenously with replication-deficient adenovirus carrying a D2R reporter gene, PET in vivo measures of hepatic [18F] retention are proportional to in vitro measures of hepatic FESP retention, D2R ligand binding and D2R mRNA. We use tumor-forming cells carrying a stably transfected D2R gene to demonstrate imaging : of this PET reporter gene/PET reporter probe system in 'tissues'. Tumors expressing the transfected D2R reporter gene retain substantially more FESP than control tumors. The D2R/FESP reporter gene/reporter probe system should be a valuable technique to monitor, in vivo, expression from both gene therapy Vectors and transgenes. C1 Univ Calif Los Angeles, Inst Mol Biol, Sch Med, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Biomath, Sch Med, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Jonsson Comprehens Canc Ctr, Sch Med, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Mol & Med Pharmacol, Sch Med, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, US DOE, Sch Med, Lab Struct Biol & Mol Med, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Crump Inst Biol Imaging, Sch Med, Los Angeles, CA 90095 USA. RP Herschman, HR (reprint author), Univ Calif Los Angeles, Inst Mol Biol, Sch Med, 611 Circle Dr E,Room 341 MBI, Los Angeles, CA 90095 USA. RI Sharfstein, Susan/G-1707-2014; OI Sharfstein, Susan/0000-0002-0908-4197 NR 44 TC 253 Z9 272 U1 0 U2 6 PU STOCKTON PRESS PI BASINGSTOKE PA HOUNDMILLS, BASINGSTOKE RG21 6XS, HAMPSHIRE, ENGLAND SN 0969-7128 J9 GENE THER JI Gene Ther. PD MAY PY 1999 VL 6 IS 5 BP 785 EP 791 DI 10.1038/sj.gt.3300877 PG 7 WC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity; Medicine, Research & Experimental SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity; Research & Experimental Medicine GA 194HN UT WOS:000080186700011 PM 10505102 ER PT J AU Rinchik, EM Carpenter, DA AF Rinchik, EM Carpenter, DA TI N-ethyl-N-nitrosourea mutagenesis of a 6-to 11-cM subregion of the Fah-Hbb interval of mouse chromosome 7: Completed testing of 4557 gametes and deletion mapping and complementation analysis of 31 mutations SO GENETICS LA English DT Article ID STRUCTURE FUNCTIONAL-ANALYSIS; EMBRYONIC STEM-CELLS; ALBINO-LOCUS REGION; LETHAL MUTATIONS; MICE; GENE; EED; RADIATION; SURVIVAL; ECTODERM AB An interval of mouse chromosome (Chr) 7 surrounding the albino (Tyr; c) locus, and corresponding to a long 6- to 11-cM Tyr deletion, has been the target of a large-scale mutagenesis screen with the chemical supermutagen N-ethyl-N-nitrosourea (ENU). A segment of Chr 7, from a mutagenized genome bred from ENU-treated males, was made hemizygous opposite the long deletion for recognition and recovery of new recessive mutations that map within the albino deletion complex. Over 6000 pedigrees were analyzed, and 4557 of these were completely tested for mutations specifying both lethal and gross visible phenotypes. Thirty-one nonclustered mutations were identified and assigned to 10 complementation groups by pairwise trans-complementation crosses. Deletion-mapping analyses, using the extensive series of radiation-induced Tyr deletions, placed the loci defined by each of these complementation groups into defined intervals of the Tyr-region deletion map, which facilitates the identification of each locus on physical and transcription maps of the region. These mutations identified seven new loci and provided new ENU-induced alleles at three previously defined loci. Interestingly, no mutations were recovered that recapitulated three phenotypes defined by analysis of homozygous or partially complementing albino deletions. On the basis of our experience with this screen, we discuss a number of issues (e.g., locus mutability, failure to saturate, number of gametes to screen, allelic series) of concern when application of chemical mutagenesis screens to megabase regions of the mouse genome is considered. C1 Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. RP Rinchik, EM (reprint author), Oak Ridge Natl Lab, Div Life Sci, POB 713, Holmes, NY 12531 USA. FU NHGRI NIH HHS [HG 00370] NR 34 TC 82 Z9 87 U1 0 U2 3 PU GENETICS PI BALTIMORE PA 428 EAST PRESTON ST, BALTIMORE, MD 21202 USA SN 0016-6731 J9 GENETICS JI Genetics PD MAY PY 1999 VL 152 IS 1 BP 373 EP 383 PG 11 WC Genetics & Heredity SC Genetics & Heredity GA 194XB UT WOS:000080219100030 PM 10224267 ER PT J AU White, PS Tatum, OL Deaven, LL Longmire, JL AF White, PS Tatum, OL Deaven, LL Longmire, JL TI New, male-specific microsatellite markers from the human Y chromosome SO GENOMICS LA English DT Article ID HUMAN GENOME; HUMAN-POPULATION; DNA LIBRARIES; CONSTRUCTION; INSERTION AB Seven novel microsatellite markers have been developed from a new cosmid library constructed from how-sorted human Y chromosomes. These microsatellites are tetranucleotide GATA repeats and are polymorphic among unrelated individuals. Five of the seven markers are male-specific, with no PCR product being generated from female DNA. One marker produces male-specific, polymorphic PCR products but occasionally produces a much larger, invariant product from female DNA. The remaining marker is polymorphic in both males and females with many shared alleles between the sexes. This report of six new, male-specific markers doubles the number of tetranucleotide markers that are currently available for the human Y chromosome. These new markers will be valuable where nonrecombining, gender-specific DNA markers are desired, including forensic investigations as well as studies of populations and their evolutionary histories. (C) 1999 Academic Press. C1 Univ Calif Los Alamos Natl Lab, Div Life Sci, Genom Grp, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Life Sci, Ctr Human Genome Studies, Los Alamos, NM 87545 USA. RP Longmire, JL (reprint author), Univ Calif Los Alamos Natl Lab, Div Life Sci, Genom Grp, POB 1663, Los Alamos, NM 87545 USA. NR 14 TC 84 Z9 93 U1 1 U2 4 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0888-7543 J9 GENOMICS JI Genomics PD MAY 1 PY 1999 VL 57 IS 3 BP 433 EP 437 DI 10.1006/geno.1999.5782 PG 5 WC Biotechnology & Applied Microbiology; Genetics & Heredity SC Biotechnology & Applied Microbiology; Genetics & Heredity GA 197CX UT WOS:000080348000013 PM 10329011 ER PT J AU Regnier, P Steefel, CI AF Regnier, P Steefel, CI TI A high resolution estimate of the inorganic nitrogen flux from the Scheldt estuary to the coastal North Sea during a nitrogen-limited algal bloom, spring 1995 SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID ECOSYSTEM MODEL MOSES; TRACE-METALS; WESTERSCHELDE ESTUARY; PHAEOCYSTIS; WATERS; RIVER; PHYTOPLANKTON; GEOCHEMISTRY; NETHERLANDS; TRANSPORT AB Massive short-term (4-8 wk) blooms of Phaeocystis have been observed in coastal North Sea waters in the spring for a number of years now. Researchers have shown that these algal blooms, which lead to eutrophication of the local water mass, are limited by the supply of inorganic nitrogen from the various bordering estuaries. We demonstrate using the case of a typical heavily polluted macrotidal estuary, the Scheldt in Belgium and the Netherlands, that the short duration of the algal blooms requires estuarine flux estimation methods with a high temporal resolution. We use the fully transient, multicomponent reactive transport model CONTRASTE to compute inorganic nitrogen fluxes through the mouth of the Scheldt estuary into the North Sea. The model simulations use a detailed dataset of upstream river discharges and solute concentrations along with tidal forcings for a 210 day period between December 1, 1994 and June 30, 1995. Our temporally resolved estimate shows that widely used estuarine flux estimation methods which rely on a steady-state approximation underestimate the inorganic nitrogen loading available to sustain primary production in the North Sea during the period of the algal bloom by 100%. Copyright (C) 1999 Elsevier Science Ltd. C1 Free Univ Brussels, Dept Oceanog, Brussels, Belgium. Natl Univ Ireland Univ Coll Cork, Dept Civil & Environm Engn, Cork, Ireland. Lawrence Livermore Natl Lab, Geosci & Environm Technol Div, Livermore, CA 94550 USA. RP Regnier, P (reprint author), Danish Hydraul Inst, Ecol Modelling Ctr, Agern Alle 5, DK-2970 Horsholm, Denmark. RI Steefel, Carl/B-7758-2010 NR 69 TC 31 Z9 31 U1 1 U2 8 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 1999 VL 63 IS 9 BP 1359 EP 1374 DI 10.1016/S0016-7037(99)00034-4 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 218PP UT WOS:000081561200008 ER PT J AU Seitz, JC Blencoe, JG AF Seitz, JC Blencoe, JG TI The CO2-H2O system. I. Experimental determination of volumetric properties at 400 degrees C, 10-100 MPa SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID CARBON-DIOXIDE; THERMODYNAMIC PROPERTIES; TEMPERATURE RELATION; HIGH-PRESSURE; 99.93 MPA; CH4-CO2-H2O SYSTEM; H2O-CO2 MIXTURES; TRIPLE-POINT; 573.15 K; EQUATION AB Densities of pure CO2 and CO2-H2O mixtures were experimentally determined at 400 degrees C, 10-100 MPa. The data were obtained with a custom-designed high-pressure, high-temperature vibrating-tube densimeter. Conservative estimates of accuracy are P, +/- 0.02 MPa, T, +/- 0.05 degrees C, and rho +/- 0.0005 to 0.0010 g.cm(-3) for low- and high-density mixtures, respectively. Excess molar volumes (V-ex) for mixtures are continuously positive, increasing sharply from 0 MPa to maximum values near 30 MPa. Above 30 MPa, V-ex decreases rapidly with increasing pressure. Peak values for V-ex are large, representing up to 37% of total volume. The isobaric data (V-ex vs. X-CO2) are nearly symmetric at pressures below 10 MPa, but become strongly asymmetric toward H2O with increasing pressure above 10 MPa. The highest degree of asymmetry coincides with P-T conditions at the critical isochore for pure H2O (similar to 29.2 MPa at 400 degrees C). With increasing pressure above 30 MPa, asymmetry of the isobaric data shifts toward CO2 Densities for pure CO(2)at 400 degrees C, 10-100 MPa, predicted by published equations of state are in fair to excellent agreement with our experimentally determined densities. Previously published density data for mixtures, and excess molar volumes calculated from equations of state, are generally in poor agreement with our results. Copyright 0 1999 Elsevier Science Ltd. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Seitz, JC (reprint author), Calif State Univ Hayward, Dept Geol Sci, 25800 Carlos Bee Blvd, Hayward, CA 94542 USA. NR 48 TC 33 Z9 34 U1 0 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 1999 VL 63 IS 10 BP 1559 EP 1569 DI 10.1016/S0016-7037(99)00050-2 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 221EG UT WOS:000081710600009 ER PT J AU Benezeth, P Palmer, DA Wesolowski, DJ AF Benezeth, P Palmer, DA Wesolowski, DJ TI The solubility of zinc oxide in 0.03 m NaTr as a function of temperature, with in situ pH measurement SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID THERMODYNAMIC PROPERTIES; ALUMINUM SPECIATION; AQUEOUS-SOLUTION; HIGH-PRESSURES; CHLORIDE; 1000-DEGREES-C; 350-DEGREES-C; 300-DEGREES-C; COMPLEXATION; HYDROLYSIS AB The solubility of zincite (ZnO) has been measured in noncomplexing solutions over a wide range of pH(m) (4-11), and temperature (75-200 degrees C) at 0.03 mol.kg(-1) ionic strength in NaTr media (sodium trifluoromethanesulfonate, a noncomplexing 1:1 electrolyte), in a hydrogen electrode concentration cell (HECC), which provided continuous in situ measurement of hydrogen ion molality. Total zinc content was analyzed by atomic absorption using graphite furnace, flame, and inductively coupled plasma (ICP) spectrometers. The direction of approach to the equilibrium saturation state was varied to demonstrate that the system was reversible thermodynamically. Separate experiments were performed in alkaline solutions (0.03 mol . kg(-1) NaOH) at 25 and 50 degrees C in polypropylene syringes, and between 50 and 290 degrees C in a Teflon-lined pressure vessel. The aim of these experiments was to reach higher pH(m) (>8 depending on the temperature) to determine the thermodynamic properties of the negatively charged species, Zn(OH)(3)(-). A least-squares regression of the results obtained at this ionic strength was used to determine the molal solubility products (Q(sn)) of zincite. The solubility products (Q(sn)) were extrapolated to infinite dilution (K-sn), permitting calculation of the thermodynamic properties of aqueous species of zinc for comparison with previous work. Copyright (C) 1999 Elsevier Science Ltd. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Benezeth, P (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RI BENEZETH, Pascale/H-7969-2014 OI BENEZETH, Pascale/0000-0002-1841-2383 NR 33 TC 32 Z9 33 U1 1 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 1999 VL 63 IS 10 BP 1571 EP 1586 DI 10.1016/S0016-7037(99)00109-X PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 221EG UT WOS:000081710600010 ER PT J AU Vasco, DW Johnson, LR Marques, O AF Vasco, DW Johnson, LR Marques, O TI Global Earth structure: inference and assessment SO GEOPHYSICAL JOURNAL INTERNATIONAL LA English DT Article DE Earth structure; heterogeneity; P wave; S wave; velocity ID INNER-CORE ANISOTROPY; DIFFERENTIAL TRAVEL-TIMES; LARGE MATRIX INVERSIONS; OUTERMOST LIQUID CORE; VELOCITY STRUCTURE; MANTLE BOUNDARY; SEISMIC TOMOGRAPHY; CONJUGATE-GRADIENT; LANCZOS-ALGORITHM; FREE OSCILLATIONS AB A suite of compressional and shear phase arrival times (P, S, PP, PcP, SS, ScS, PKPab, PKPbc, PRPdf, SKSac) and two sets of differential times (SS-S410S, SS-S660S) are used to infer lateral variations in P and S velocity structure in the entire Earth (crust, mantle and core). Volumetric heterogeneity is parametrized by 22 depth layers, each of which is subdivided into a grid of cells. In addition to volumetric heterogeneity, we determine topography on the major internal velocity discontinuities, station corrections, event relocation parameters and inner core anisotropy, a total of 96300 unknowns. The model parameters are estimated using an iterative Lanczos algorithm to obtain a partial singular value decomposition. A total of 5000 Lanczos values and vectors are used to construct model parameter estimates as well as measures of model parameter resolution and covariance. The Lanczos resolution estimates provide lower bounds on conventional SVD-based measures. Throughout most of the mantle we find that regions beneath the continents, particularly in the Northern Hemisphere, are well resolved. With the exception of Africa, velocity variations are moderately well resolved in that portion of the outer core lying beneath the continents. Velocity heterogeneity is poorly resolved in the inner core where cell dimensions are small and deviations in velocity heterogeneity trade off with variations in anisotropy. Variations in the uppermost mantle (2-3 per cent) are correlated with surface tectonics, while at greater depths high-velocity variations coincide with regions of past and present subduction. The high-velocity anomalies extend into the lower mantle, although with a reduced amplitude (0.5-1.0 per cent) until the lowest mantle (2.5 per cent). At the base of the outer core a large-scale pattern of heterogeneity (0.8 per cent) is observed, slower at the poles. In the inner core we infer a peak anisotropy of 2-3 per cent which varies laterally and with depth. However, the magnitude and distribution of the anisotropy trades off strongly with velocity heterogeneity. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Computat Seismol, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Natl Energy Res Sci Comp Ctr, Berkeley, CA 94720 USA. Univ Calif Berkeley, Berkeley Seismol Lab, Berkeley, CA 94720 USA. RP Vasco, DW (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Computat Seismol, 1 Cyclotron Rd, Berkeley, CA 94720 USA. RI Vasco, Donald/I-3167-2016 OI Vasco, Donald/0000-0003-1210-8628 NR 91 TC 22 Z9 22 U1 0 U2 1 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0956-540X J9 GEOPHYS J INT JI Geophys. J. Int. PD MAY PY 1999 VL 137 IS 2 BP 381 EP 407 DI 10.1046/j.1365-246X.1999.00823.x PG 27 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 194WX UT WOS:000080218700007 ER PT J AU Sperber, KR AF Sperber, KR CA Participating AMIP Modelling Grp TI Are revised models better models? A skill score assessment of regional interannual variability SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID INTERCOMPARISON PROJECT; MONSOON; AMIP; PRECIPITATION; SENSITIVITY; RAINFALL; GCM AB Various skill scores are used to assess the performance of revised models relative to their original configurations. The interannual variability of all-India, Sahel and Nordeste rainfall and summer monsoon windshear is examined in integrations performed under the experimental design of the Atmospheric Model Intercomparison Project. For the indices considered, the revised models exhibit greater fidelity at simulating the observed interannual variability. Interannual variability of all-India rainfall is better simulated by models that have a more realistic rainfall climatology in the vicinity of India, indicating the beneficial effect of reducing systematic model error. C1 Univ Calif Lawrence Livermore Natl Lab, PCMDI, Livermore, CA 94550 USA. Res Ctr, Bur Meteorol, Melbourne, Vic, Australia. Ctr Natl Rech Meteorol, Toulouse, France. Dept Numer Math, Moscow, Russia. DERF, Geophys Fluid Dynam Lab, Princeton, NJ USA. Meteorol Dynam Lab, Paris, France. Max Planck Inst Meteorol, Hamburg, Germany. Meteorol Res Inst, Tsukuba, Ibaraki 305, Japan. USN, Res Lab, Monterey, CA USA. SUNY Albany, SNG, Albany, NY 12222 USA. Yonsei Univ, Seoul 120749, South Korea. RP Sperber, KR (reprint author), Univ Calif Lawrence Livermore Natl Lab, PCMDI, POB 808,L-264, Livermore, CA 94550 USA. RI Sperber, Kenneth/H-2333-2012 NR 23 TC 17 Z9 17 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 1 PY 1999 VL 26 IS 9 BP 1267 EP 1270 DI 10.1029/1999GL900227 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 193EL UT WOS:000080122900021 ER PT J AU Carr, BJ Hajnal, Z AF Carr, BJ Hajnal, Z TI P- and S-wave characterization of near-surface reflectivity from glacial tills using vertical seismic profiles SO GEOPHYSICS LA English DT Article AB Fundamental reflectivity properties are established within the glacial deposits of central Saskatchewan, Canada. Multicomponent vertical seismic profile (VSP) data collected in three shallow boreholes are used to obtain detailed acoustic property information within the first 80 m of the near-surface strata. The integration of both P- and S-wave VSP data, in conjunction with other borehole geophysics, provided a unique opportunity to obtain in-situ seismic reflection response properties in layered clay and sand tills. P- and S-wave interval velocity profiles, in conjunction with P- and S-wave VSP reflectivities are analyzed to provide insight into seismic wavefield behavior within similar to 80 m of the surface. In general, shear wave energy identifies more reflective intervals than the P-wave energy because of better vertical resolution for S-wave energy (0.75 m) compared to P-wave energy (2.3 m) based on quarter wavelength criterion. For these saturated, unconsolidated glacial deposits, more details about the lithologic constituents and in-situ porosity are detectable from the S-wave reflectivity, but P-wave reflections provide a good technique for mapping the bulk changes. The principal cause of seismic reflectivity is the presence and/or amount of sand, and the degree of fluid-filled porosity within the investigated formations. C1 Univ Saskatchewan, Dept Geol Sci, Saskatoon, SK S7N 5E2, Canada. RP Carr, BJ (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. NR 10 TC 4 Z9 4 U1 0 U2 1 PU SOC EXPLORATION GEOPHYSICISTS PI TULSA PA 8801 S YALE ST, TULSA, OK 74137 USA SN 0016-8033 J9 GEOPHYSICS JI Geophysics PD MAY-JUN PY 1999 VL 64 IS 3 BP 970 EP 980 DI 10.1190/1.1444606 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 203JA UT WOS:000080703600034 ER PT J AU Adams, JM Post, WM AF Adams, JM Post, WM TI A preliminary estimate of changing calcrete carbon storage on land since the Last Glacial Maximum SO GLOBAL AND PLANETARY CHANGE LA English DT Article DE calcrete; carbonate; carbon cycle; LGM; Holocene ID SUBTROPICAL SOILS; VEGETATION; WORLD AB The glacial-to-interglacial shift in land carbon storage is important in understanding the global carbon cycle and history of the climate system. While organic carbon storage on land appears to have been much less than present during the cold, dry glacial maximum, calcrete (soil carbonate) carbon storage would have been greater. Here we attempt a global estimation of this change; we use published figures for present soil carbonate by biome to estimate changing global soil carbonate storage, on the basis of reconstruction of vegetation areas for four timeslices since the Last Glacial Maximum. It appears that there would most likely have been around a 30-45% decrease in calcrete carbon on land accompanying the transition between glacial and interglacial conditions. This represents a change of about 500-400 GtC (outer error Limits are estimated at 750-200 GtC). In order to be weathered into dissolved bicarbonate, this would take up an additional 500-400 GtC (750-200 GtC) in CO2 from ocean/atmosphere sources. An equivalent amount to the carbonate leaving the caliche reservoir on land may have accumulated in coral reefs and other calcareous marine sediments during the Holocene, liberating an equimolar quantity of CO2 back into the ocean-atmosphere system as the bicarbonate ion breaks up. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Univ Adelaide, Dept Environm & Geog Sci, Adelaide, SA 5005, Australia. RP Adams, JM (reprint author), Oak Ridge Natl Lab, Div Environm Sci, Bldg 1509,MS 6335, Oak Ridge, TN 37831 USA. RI Post, Wilfred/B-8959-2012 NR 29 TC 20 Z9 21 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8181 J9 GLOBAL PLANET CHANGE JI Glob. Planet. Change PD MAY PY 1999 VL 20 IS 4 BP 243 EP 256 DI 10.1016/S0921-8181(99)00015-6 PG 14 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 215BP UT WOS:000081362300003 ER PT J AU Becker, MW Reimus, PW Vilks, P AF Becker, MW Reimus, PW Vilks, P TI Transport and attenuation of carboxylate-modified latex microspheres in fractured rock laboratory and field tracer tests SO GROUND WATER LA English DT Article ID COLLOID TRANSPORT; SANDY AQUIFER; MIGRATION EXPERIMENTS; GRANITE FRACTURE; POROUS-MEDIA; BACTERIA; MICROORGANISMS; SEDIMENTS; PARTICLES; BEHAVIOR AB Understanding colloid transport in ground water is essential to assessing the migration of colloid-size contaminants, the facilitation of dissolved contaminant transport by colloids, in situ bioremediation, and the health risks of pathogen contamination in drinking water wells, Much has been learned through laboratory and field-scale colloid tracer tests, but progress has been hampered by a lack of consistent tracer testing methodology at different scales and fluid velocities. This paper presents laboratory and field tracer tests in fractured rock that use the same type of colloid tracer over an almost three orders-of-magnitude range in scale and fluid velocity Fluorescently-dyed carboxylate-modified latex (CML) microspheres (0.19 to 0.98 mu m diameter) were used as tracers in (1) a naturally fractured tuff sample, (2) a large block of naturally fractured granite, (3) a fractured granite field site, and (4) another fractured granite/schist field site. In all cases, the mean transport time of the microspheres was shorter than the solutes, regardless of detection limit. In all but the smallest scale test, only a fraction of the injected microsphere mass was recovered, with the smaller microspheres being recovered to a greater extent than the larger microspheres, Using existing theory, we hypothesize that the observed microsphere early arrival was due to volume exclusion and attenuation was due to aggregation and/or settling during transport. In most tests, microspheres were detected using flow cytometry, which proved to be an excellent method of analysis. CML microspheres appear to be useful tracers for fractured rock in forced gradient and short-term natural gradient tests, but longer residence times may result in small microsphere recoveries. C1 US Geol Survey, Div Water Resources, Reston, VA 20192 USA. Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Whiteshell Labs, Geochem Res Branch, Pinawa, MB R0E 1L0, Canada. RP Becker, MW (reprint author), SUNY Buffalo, Dept Geog, Buffalo, NY 14260 USA. RI Becker, Matthew/J-2711-2012 NR 33 TC 43 Z9 44 U1 1 U2 12 PU GROUND WATER PUBLISHING CO PI WESTERVILLE PA 601 DEMPSEY RD, WESTERVILLE, OH 43081 USA SN 0017-467X J9 GROUND WATER JI Ground Water PD MAY-JUN PY 1999 VL 37 IS 3 BP 387 EP 395 DI 10.1111/j.1745-6584.1999.tb01116.x PG 9 WC Geosciences, Multidisciplinary; Water Resources SC Geology; Water Resources GA 191ZA UT WOS:000080051100013 ER PT J AU Richards, NW AF Richards, NW TI Prediction of in vivo background in phoswich lung count spectra SO HEALTH PHYSICS LA English DT Article DE actinides; K-40; lungs, human; detector, phoswich AB Phoswich scintillation counters are used to detect actinides deposited in the lungs. The resulting spectra, however, contain Compton background from the decay of K-40, which occurs naturally in the striated muscle tissue of the body. To determine the counts due to actinides in a lung count spectrum, the counts due to K-40 scatter must first be subtracted out. The K-40 background in the phoswich NaI(Tl) spectrum was predicted front an energy region of interest called the monitor region (95-129 keV), which is above the Pu-238 region (11-32 keV) and the Am-241 region (40-82 keV), where photopeaks from Pu-238 and Am-241 occur. Empirical models were developed to predict the backgrounds in the Pu-238 and Am-241 regions by testing multiple linear and nonlinear regression models. The initial multiple regression models contain a monitor region variable as well as the variables gender, (weight/height)(alpha), and interaction terms. Data were collected from 64 male and 63 female subjects with no internal exposure. For the Pu-238 region, the only significant predictor was found to be the monitor region. For the Am-241 region, the monitor region was found to have the greatest effect on prediction, while gender was significant only when weight/height was included in a model. Gender-specific models were thus developed. The empirical models for the Am-241 region that contain weight/height were shown to have the best coefficients of determination (R-2) and the lowest mean squares for error (MSE). C1 Oak Ridge Natl Lab, Off Radiat Protect, Oak Ridge, TN 37831 USA. NR 12 TC 1 Z9 1 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD MAY PY 1999 VL 76 IS 5 BP 524 EP 531 DI 10.1097/00004032-199905000-00009 PG 8 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 184AZ UT WOS:000079588300008 PM 10201566 ER PT J AU Cavallo, A Hutter, A Shebell, P AF Cavallo, A Hutter, A Shebell, P TI Radon progeny unattached fraction in an atmosphere far from radioactive equilibrium SO HEALTH PHYSICS LA English DT Article DE radon progeny; uranium mines; exposure, population; ventilation AB It is often assumed that the unattached fraction of the exposure to suspended radon progeny activity can be predicted from particle concentration measurements, While this may be true in many circumstances, there are important exceptions to this rule. In particular, in an atmosphere far from radioactive equilibrium, such as a working area in a mine close to a source of radon and supplied with fresh air, the unattached fraction can be a factor of ten or more greater than indicated by a simple particle concentration measurement. Recent measurements made in a diesel powered uranium mine are presented to illustrate this effect. C1 US DOE, Environm Measurements Lab, New York, NY 10014 USA. NR 20 TC 5 Z9 6 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD MAY PY 1999 VL 76 IS 5 BP 532 EP 536 DI 10.1097/00004032-199905000-00010 PG 5 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 184AZ UT WOS:000079588300009 PM 10201567 ER PT J AU Miller, ML Cornish, RE Pomatto, CB AF Miller, ML Cornish, RE Pomatto, CB TI Calculation of the number of cancer deaths prevented by the Uranium Mill Tailings Remedial Action Project SO HEALTH PHYSICS LA English DT Article DE cancer; uranium; cost-benefit analysis; decontamination AB The Uranium Mill Tailings Remedial Action Project has completed remedial action at 22 uranium mill tailings sites and about 5,000 properties ("vicinity properties") where tailings were used in construction, at a total cost of $1.45 billion, This paper uses existing data from Environmental Impact Statements and Environmental Assessments, and vicinity property calculations, to determine the total number of cancer deaths averted by the Uranium Mill Tailings Remedial Action Project. The cost-effectiveness of remediating each site, the vicinity properties, and the entire project is calculated, The cost per cancer death averted was four orders of magnitude higher at the least cost-effective site than at the most cost-effective site. C1 Roy F Weston Inc, Albuquerque, NM 87110 USA. US DOE, Albuquerque Operat Off, Albuquerque, NM 87116 USA. NR 2 TC 1 Z9 1 U1 3 U2 3 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD MAY PY 1999 VL 76 IS 5 BP 544 EP 546 DI 10.1097/00004032-199905000-00012 PG 3 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 184AZ UT WOS:000079588300011 PM 10201569 ER PT J AU Frame, PW Abelquist, EW AF Frame, PW Abelquist, EW TI Use of smears for assessing removable contamination SO HEALTH PHYSICS LA English DT Article DE contamination; operational topics; contamination, environmental; wipe tests ID SURFACE CONTAMINATION AB It is the authors' recommendation that all non-fixed contamination limits apply to the total non-fixed surface contamination on an object or structure rather than the activity removed by a single wipe. This would bring the United States in line with the international approach, something that would be particularly helpful with respect to the international shipment of radioactive material. It would also provide a consistant approach within the United States for the characterization of non-fixed contamination, something that does not currently exist. C1 Oak Ridge Inst Sci & Educ, Oak Ridge, TN 37831 USA. EM framep@orau.gov NR 28 TC 5 Z9 5 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD MAY PY 1999 VL 76 IS 5 SU S BP S57 EP S66 DI 10.1097/00004032-199905001-00004 PG 10 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 185GX UT WOS:000079660700003 ER PT J AU Vickers, LD Wehring, BW AF Vickers, LD Wehring, BW TI Dismantlement of the US W48 nuclear warheads SO HEALTH PHYSICS LA English DT Article DE radiation protection; radiation risk; radiation dose; operational topic AB The United States Department of Energy Pantex Plant serves as the nation's only assembly facility for the nuclear weapons stockpile. There were more than 300 W48 Artillery Fired Atomic Projectile nuclear warheads dismantled between May 1995 and April 1996 at the U.S. DOE Pantex plant. There was no removable alpha contamination detected during this dismantlement period. The dismantlement of the W48 nuclear warheads necessitates only the mitigation of externa; radiation exposure. The radiological protection measures implemented for the W48 program included lead aprons, lead lined gloves, and shielded fixtures. These radiological protection measures were attributed for maintaining all exposures to personnel As Low As Reasonably Achievable (ALARA) and less than the Pantex Plant Administration Control Levels of 1,000 mrem (10mSv) total equivalent dose effective whole body and 10,000 (100 mSv) extremities. The U.S. DOE Pantex Plant continues to serve and secure the national security of the Unite States by performing safe dismantlements of the nation's nuclear weapons stockpile in a manner that protects the health and safely of employees, the public, and the environment. C1 US DOE, Pantex Plant, Risk Management Dept, Amarillo, TX 79120 USA. Univ Texas, Nucl Engn Teaching Lab, Austin, TX 78712 USA. EM lvickers@pantex.com NR 0 TC 3 Z9 3 U1 0 U2 2 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD MAY PY 1999 VL 76 IS 5 SU S BP S83 EP S86 DI 10.1097/00004032-199905001-00008 PG 4 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 185GX UT WOS:000079660700007 ER PT J AU Jong, MTC Carey, AH Caldwell, KA Lau, MH Handel, MA Driscoll, DJ Stewart, CL Rinchik, EM Nicholls, RD AF Jong, MTC Carey, AH Caldwell, KA Lau, MH Handel, MA Driscoll, DJ Stewart, CL Rinchik, EM Nicholls, RD TI Imprinting of a RING zinc-finger encoding gene in the mouse chromosome region homologous to the Prader-Willi syndrome genetic region SO HUMAN MOLECULAR GENETICS LA English DT Article ID 3' UNTRANSLATED REGION; EMBRYONIC STEM-CELLS; ANGELMAN-SYNDROME; SPERMATOGENIC CELLS; MESSENGER-RNA; NECDIN GENE; SNRPN GENE; EXPRESSION; METHYLATION; IGF2R AB A novel locus in the human Prader-Willi syndrome (PWS) region encodes the imprinted ZNF127 and anti-sense ZNF127AS genes. Here, we show that the mouse ZNF127 ortholog, Zfp127, encodes a homologous putative zinc-finger polypeptide, with a RING (C3HC4) and three C3H zinc-finger domains that suggest function as a ribonucleoprotein, By the use of RT-PCR across an in-frame hexamer tandem repeat and RNA from a Mus musculusxM.spretus F-1 interspecific cross, we show that Zfp127 is expressed only from the paternal allele in brain, heart and kidney. Similarly, Zfp127 is expressed in differentiated cells derived from androgenetic embryonic stem cells and normal embryos but not those from parthogenetic embryonic stem cells. We hypothesize that the gametic imprint may be set, at least in part, by the transcriptional activity of Zfp127 in pre- and post-meiotic male germ cells. Therefore, Zfp127 is a novel imprinted gene that may play a role in the imprinted phenotype of mouse models of PWS. C1 Case Western Reserve Univ, Sch Med, Dept Genet, Cleveland, OH 44106 USA. Univ Hosp Cleveland, Ctr Human Genet, Cleveland, OH 44106 USA. Univ Florida, Coll Med, Div Pediat Genet, RC Philips Unit, Gainesville, FL 32610 USA. Univ Florida, Coll Med, Ctr Mammalian Genet, Gainesville, FL 32610 USA. Roche Inst Mol Biol, Nutley, NJ 07110 USA. Univ Tennessee, Dept Biochem & Cellular & Mol Biol, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. RP Nicholls, RD (reprint author), Case Western Reserve Univ, Sch Med, Dept Genet, 10900 Euclid Ave, Cleveland, OH 44106 USA. FU NICHD NIH HHS [HD34191, HD36079] NR 49 TC 69 Z9 70 U1 0 U2 1 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0964-6906 J9 HUM MOL GENET JI Hum. Mol. Genet. PD MAY PY 1999 VL 8 IS 5 BP 795 EP 803 DI 10.1093/hmg/8.5.795 PG 9 WC Biochemistry & Molecular Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Genetics & Heredity GA 192ZG UT WOS:000080109200008 PM 10196368 ER PT J AU Kim, JY Lu, XC Stubbs, L AF Kim, JY Lu, XC Stubbs, L TI Zim1, a maternally expressed mouse Kruppel-type zinc-finger gene located in proximal chromosome 7 SO HUMAN MOLECULAR GENETICS LA English DT Article ID TRANSCRIPTIONAL REPRESSION; IMPRINTED EXPRESSION; ANGELMAN-SYNDROME; PRADER-WILLI; REGION; MAP; AMPLIFICATION; PROTEINS; CLUSTERS; ENCODES AB In analysis of a conserved region of proximal mouse chromosome 7 and human chromosome 19q, we have isolated a novel mouse gene, Zim1 (imprinted zinc-finger gene 1), encoding a typical Kruppel-type (C2H2) zinc-finger protein, located within 30 kb of a known imprinted gene, Peg3 (paternally expressed gene 3), Our studies demonstrate that Zim1 is also imprinted; the gene is expressed mainly from the maternal allele and at high levels only during embryonic and neonatal stages. In contrast to most tissues, Zim1 is expressed biallelically in neonatal and adult brain with slightly more input from the maternal allele, Zim1 produces multiple transcripts that range in size from 7.5 to 15 kb, The 7.5 kb transcript is expressed at highest levels and appears to be embryo specific, Whole mount in situ hybridization analysis indicates that Zim1 is expressed at significant levels in the apical ectodermal ridge of the limb buds during embryogenesis, suggesting a potential role of Zim1 in limb formation. We have identified the potential human ortholog of Zim1 near PEG3 in a conserved, gene-rich region of human chromosome 19q13.4. The close juxtaposition of reciprocally imprinted genes has also been seen in other imprinted regions, such as human 11p15.5/Mmu7 (H19/Igf2) and suggests that the two genes may be co-regulated. These and other data suggest the presence of an unexplored, conserved imprinted domain in human chromosome 19q13.4 and proximal Mmu7. C1 Univ Calif Lawrence Livermore Natl Lab, Human Genome Ctr, Biol & Biotechnol Res Program, Livermore, CA 94551 USA. RP Kim, JY (reprint author), Univ Calif Lawrence Livermore Natl Lab, Human Genome Ctr, Biol & Biotechnol Res Program, L-452,7000 E Ave, Livermore, CA 94551 USA. OI Stubbs, Lisa/0000-0002-9556-1972 NR 40 TC 45 Z9 47 U1 0 U2 2 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0964-6906 J9 HUM MOL GENET JI Hum. Mol. Genet. PD MAY PY 1999 VL 8 IS 5 BP 847 EP 854 DI 10.1093/hmg/8.5.847 PG 8 WC Biochemistry & Molecular Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Genetics & Heredity GA 192ZG UT WOS:000080109200014 PM 10196374 ER PT J AU La Roche, J McKay, RML Boyd, P AF La Roche, J McKay, RML Boyd, P TI Immunological and molecular probes to detect phytoplankton responses to environmental stress in nature SO HYDROBIOLOGIA LA English DT Article; Proceedings Paper CT Special Session on the Application of Molecular Techniques to Aquatic Communities, at the American-Society-for-Limnology-and-Oceanography-Aquatic-Sciences Meeting CY 1997 CL SANTA FE, NM SP Amer Soc Limnol & Oceanog Aquat Sci DE phytoplankton physiological status; probes for phytoplankton; nutrient deficiency; iron limitation in phytoplankton; nitrogen limitation in phytoplankton; flavodoxin; plastocyanin; trace metal toxicity; MAA; superoxide dismutase ID EQUATORIAL PACIFIC-OCEAN; LIGHT-INDUCIBLE PROTEIN; SUB-ARCTIC PACIFIC; COMPLETE NUCLEOTIDE-SEQUENCE; GLOBAL NITROGEN REGULATOR; SYNECHOCOCCUS SP WH-7803; SP STRAIN PCC7942; BLUE-GREEN-ALGAE; DISPLAY RT-PCR; MARINE-PHYTOPLANKTON AB Recent advances in using immunological and nucleic acid probes to detect the effects of environmental stress on phytoplankton growth rate and yield are reviewed here. The rationale for this approach is discussed in the context of the general response observed from microorganisms grown under stress imposed by various environmental factors. Retrenchment, or the observed down-regulation of metabolic processes under nutrient deficiency, is categorized as a general response that is of limited use in designing probes to stress induced by a specific nutrient. In contrast, compensation and the increase capacity for nutrient acquisition are specific responses that appear more promising for the development of such probes. Methods and approaches used to design immunological and nucleic acid probes for stress imposed by nutrient deficiency are reviewed. Specific examples for iron and nitrogen limitation are presented to demonstrate the potential use of nutrient stress indicators in natural populations of phytoplankton. Finally, the limitations of this approach and the importance of understanding the regulation of the genes and proteins used to prepare the probes are emphasized. C1 Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. Bowling Green State Univ, Dept Biol Sci, Bowling Green, OH 43403 USA. Univ Otago, Dept Chem, NIWA Ctr Chem & Phys Oceanog, Dunedin, New Zealand. RP Univ Kiel, Inst Meereskunde, Dusternbrooker Weg 20, D-24105 Kiel, Germany. RI LaRoche, Julie/A-1109-2010; Boyd, Philip/J-7624-2014; OI Boyd, Philip/0000-0001-7850-1911; McKay, Robert/0000-0003-2723-5371 NR 188 TC 25 Z9 26 U1 0 U2 10 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0018-8158 EI 1573-5117 J9 HYDROBIOLOGIA JI Hydrobiologia PD MAY PY 1999 VL 401 BP 177 EP 198 PG 22 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 248LR UT WOS:000083276500014 ER PT J AU Stulen, RH Sweeney, DW AF Stulen, RH Sweeney, DW TI Extreme ultraviolet lithography SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article DE lithography; semiconductor device manufacture ID PROJECTION AB Current microlithography used in high-volume integrated circuit manufacturing employs some form of optical projection technology. The most advanced tools use deep-ultraviolet (DUV) radiation having a wavelength of 248 nm and are used to print 250-nm features. These tools will likely be extended for use at the 180-nm generation and perhaps below. New DUV tools using 193-nm radiation are actively under development and are expected to be used for 130-nm generation and perhaps even 100-nm generation. Extending these DUV optical projection tools for manufacturing in the 100-200-nm region mill be paced by the development of nem high numerical aperture imaging systems and highly complex phase shift masks. For future generations of integrated circuits with minimum feature sizes below 100 nm, 193-nm tools mill have great difficulty meeting all manufacturing requirements, This paper describes an alternate optical approach, for sub-100-nm generations, based on extreme ultraviolet radiation at around 13 nm, called extreme ultraviolet lithography (EUVL), This approach uses a laser-produced plasma source of radiation, a reflective mask, and a 4x reduction all-reflective imaging system. The technology is currently in the engineering development phase for an alpha machine. This paper reviews its current status and describes the basic modules or building blocks of a generic EUVL exposure tool. C1 Sandia Natl Labs, Livermore, CA 94550 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Stulen, RH (reprint author), Sandia Natl Labs, Livermore, CA 94550 USA. NR 15 TC 145 Z9 147 U1 1 U2 19 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD MAY PY 1999 VL 35 IS 5 BP 694 EP 699 DI 10.1109/3.760315 PG 6 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 192XE UT WOS:000080104400002 ER PT J AU Attwood, DT Naulleau, P Goldberg, KA Tejnil, E Chang, C Beguiristain, R Batson, P Bokor, J Gullikson, EM Koike, M Medecki, H Underwood, JH AF Attwood, DT Naulleau, P Goldberg, KA Tejnil, E Chang, C Beguiristain, R Batson, P Bokor, J Gullikson, EM Koike, M Medecki, H Underwood, JH TI Tunable coherent radiation in the soft X-ray and extreme ultraviolet spectral regions SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article DE coherent radiation; extreme ultraviolet; radiation; soft X-rays; undulator ID SYNCHROTRON-RADIATION; INTERFEROMETRY; UNDULATORS; BEAMLINE; WIGGLER; OPTICS; ESRF AB Undulator radiation, generated by relativistic electrons traversing a periodic magnet structure, can provide a continuously tunable source of very bright and partially coherent radiation in the extreme ultraviolet (EUV), soft X-ray (SXR), and X-ray regions of the electromagnetic spectrum. Typically, 1-10 W are radiated within a 1/N relative spectral bandwidth, where N is of order 100, Monochromators are frequently used to narrow the spectral bandwidth and increase the longitudinal coherence length, albeit with a more than proportionate loss of power. Pinhole spatial filtering is employed to provide spatially coherent radiation at a power level determined by the wavelength, electron beam, and undulator parameters. In this paper, experiments are described in which broadly tunable, spatially coherent power is generated at EUV and soft X-ray wavelengths extending from about 3 to 16 nm (80-430-eV photon energies). Spatially coherent power of order 10 mu W is achieved in a relative spectral bandwidth of 9 x 10(-4), with 1.90-GeV electrons traversing an 8-cm period undulator of 55 periods. This radiation has been used in 13.4-nm interferometric tests that achieve an rms wavefront error (departure from sphericity) of lambda(euv)/330, These techniques scale in a straightforward manner to shorter soft X-ray wavelengths using 4-5-cm period undulators at 1.90 GeV and to X-ray wavelengths of order 0.1 nm using higher energy (6-8 GeV) electron beams at other facilities. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Xray Opt, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Elect Engn & Comp Sci, Berkeley, CA 94720 USA. Intel Corp, Santa Clara, CA USA. Japan Atom Energy Res Inst, Kyoto, Japan. RP Attwood, DT (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Xray Opt, Div Mat Sci, Berkeley, CA 94720 USA. RI Bokor, Jeffrey/A-2683-2011 NR 50 TC 46 Z9 46 U1 2 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD MAY PY 1999 VL 35 IS 5 BP 709 EP 720 DI 10.1109/3.760317 PG 12 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 192XE UT WOS:000080104400004 ER PT J AU Chen, HL Francis, D Nguyen, T Yuen, WP Li, G Chang-Hasnain, C AF Chen, HL Francis, D Nguyen, T Yuen, WP Li, G Chang-Hasnain, C TI Collimating diode laser beams from a large-area VCSEL-array using microlens array SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Article DE monolithic microlens arrays; monolithic VCSEL arrays; optical fiber coupling AB In this letter, rye demonstrate the fabrication and bonding of a 1 cm x I cm monolithic two-dimensional (2-D) vertical-cavity surface-emitting laser (VCSEL) array, We coupled the array to a matched microlens array to individually collimate light from each laser, We found the beam divergence of the collimated array to be 1.6 degrees (1/e(2)) for the entire array. Using st l-cm diameter F2 lens, we were able to focus the collimated beams to a spot of 400 mu m in diameter and to couple more than 75% of the array power into a I-mm core fiber. Our results show that it is possible to uniformly bond large area VCSEL arrays to heat sinks, and to collimate light from each element into parallel beams using a single 2-D microlens array, Our results also show that the brightness of the focused beam can be further increased with a lens to near 10(5)-W/cm(2) Steradian, a level that is useful for many high-power applications. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Berkeley, Berkeley, CA 94107 USA. RP Chen, HL (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 4 TC 6 Z9 6 U1 0 U2 8 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1041-1135 J9 IEEE PHOTONIC TECH L JI IEEE Photonics Technol. Lett. PD MAY PY 1999 VL 11 IS 5 BP 506 EP 508 DI 10.1109/68.759380 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 189MY UT WOS:000079910200004 ER PT J AU Clement, JJ Riege, SP Cvijetic, R Thompson, CV AF Clement, JJ Riege, SP Cvijetic, R Thompson, CV TI Methodology for electromigration critical threshold design rule evaluation SO IEEE TRANSACTIONS ON COMPUTER-AIDED DESIGN OF INTEGRATED CIRCUITS AND SYSTEMS LA English DT Article DE design rules; electromigration; interconnect; reliability ID RELIABILITY-ANALYSIS; CURRENT-DENSITY; FAILURE; LENGTH; FILMS; LINES AB We propose a methodology using nodal analysis techniques compatible with existing computer-aided design (CAD) tools for implementing critical threshold design rules for electromigration reliability, The concept underlying critical threshold design rules is the observation that a mechanical stress-induced backflow of metal atoms is created by electromigration in interconnect lines confined by a rigid dielectric, If the steady-state balance of these two atomic fluxes is achieved before critical electromigration damage is realized, then the line can be considered to be virtually immortal with negligible reliability risk. A design rule based on this critical threshold criterion has the potential to give designers added flexibility to use currents larger than present design rules typically allow in short interconnects. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Compaq Comp Corp, Shrewsbury, MA 01545 USA. MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA. RP Clement, JJ (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 19 TC 19 Z9 19 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0278-0070 J9 IEEE T COMPUT AID D JI IEEE Trans. Comput-Aided Des. Integr. Circuits Syst. PD MAY PY 1999 VL 18 IS 5 BP 576 EP 581 DI 10.1109/43.759073 PG 6 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 189ZQ UT WOS:000079937400006 ER PT J AU Simpson, ML Ericson, MN Jellison, GE Dress, WB Wintenberg, AL Bobrek, M AF Simpson, ML Ericson, MN Jellison, GE Dress, WB Wintenberg, AL Bobrek, M TI Application specific spectral response with CMOS compatible photodiodes SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article DE photodiodes; spectroscopy ID IMAGE SENSOR; FORM; CELL AB Several methods are presented for realizing photodiodes with independent spectral responses in a standard CMOS integrated circuit process. Only the masks, materials, and fabrication steps inherent to this standard process mere used. The spectral responses of the photodiodes were controlled by 1) using the SiO2 and polycrystalline Si as thin-film optical filters, 2) using photodiodes with different junction depths, and 3) controlling the density of the interfacial trapping centers by choosing which oxide forms the Si/SiO2 interface. Also presented is an example method for constructing photo-spectrometers using these spectrally-independent photodiodes. This methods forms weighted sums of the photodiodes' outputs to extract spectrographic information. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Tennessee, Knoxville, TN 37996 USA. RP Simpson, ML (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Simpson, Michael/A-8410-2011 OI Simpson, Michael/0000-0002-3933-3457 NR 23 TC 23 Z9 23 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9383 J9 IEEE T ELECTRON DEV JI IEEE Trans. Electron Devices PD MAY PY 1999 VL 46 IS 5 BP 905 EP 913 DI 10.1109/16.760396 PG 9 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 190JT UT WOS:000079960000012 ER PT J AU Ashikhmin, A Litsyn, S AF Ashikhmin, A Litsyn, S TI Upper bounds on the size of quantum codes SO IEEE TRANSACTIONS ON INFORMATION THEORY LA English DT Article DE linear programming; quantum codes; upper bounds ID ERROR-CORRECTING CODES AB This paper is concerned with bounds for quantum error-correcting codes, Using the quantum MacWilliams identities, we generalize the linear programming approach from classical coding theory to the quantum case. Using this approach, we obtain Singleton-type, Hamming-type, and the first linear-programming-type bounds for quantum codes. Using the special structure of linear quantum codes, we derive an upper bound that is better than both Hamming and the first linear programming bounds on some subinterval of rates. C1 Univ Calif Los Alamos Natl Lab, Grp CIC3, Los Alamos, NM 87545 USA. Tel Aviv Univ, Dept Elect Engn Syst, IL-69978 Tel Aviv, Israel. RP Ashikhmin, A (reprint author), Univ Calif Los Alamos Natl Lab, Grp CIC3, M-S P990, Los Alamos, NM 87545 USA. NR 27 TC 28 Z9 28 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9448 J9 IEEE T INFORM THEORY JI IEEE Trans. Inf. Theory PD MAY PY 1999 VL 45 IS 4 BP 1206 EP 1215 DI 10.1109/18.761270 PG 10 WC Computer Science, Information Systems; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 191TK UT WOS:000080037500012 ER PT J AU Ashikhmin, A Barg, A Litsyn, S AF Ashikhmin, A Barg, A Litsyn, S TI New upper bounds on generalized weights SO IEEE TRANSACTIONS ON INFORMATION THEORY LA English DT Article DE constant-weight codes; distance distribution; generalized weights; linear programming ID CODE; SUPPORTS AB We derive new asymptotic upper bounds on the generalized weights of a binary linear code of a given size. We also prove some asymptotic results on the distance distribution of binary codes. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. AT&T Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. Tel Aviv Univ, Dept Elect Engn Syst, IL-69978 Tel Aviv, Israel. RP Los Alamos Natl Lab, M-S P990, Los Alamos, NM 87545 USA. EM alexei@c3serve.c3.lanl.gov; abarg@research.bell-labs.com; litsyn@eng.tau.ac.il NR 18 TC 11 Z9 11 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9448 EI 1557-9654 J9 IEEE T INFORM THEORY JI IEEE Trans. Inf. Theory PD MAY PY 1999 VL 45 IS 4 BP 1258 EP 1263 DI 10.1109/18.761280 PG 6 WC Computer Science, Information Systems; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 191TK UT WOS:000080037500022 ER PT J AU White, DA AF White, DA TI Orthogonal vector basis functions for time domain finite element solution of the vector wave equation SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 8th Biennial IEEE Conference on Electromagnetic Field Computation (IEEE CEFC 98) CY JUN 01-03, 1998 CL TUCSON, AZ SP IEEE DE finite element methods; numerical analysis; convergence of numerical methods; electromagnetic fields; electromagnetic transient analysis ID ELECTROMAGNETIC-FIELD COMPUTATION; MAXWELLS EQUATIONS; WETD AB In this paper we consider the solution of the vector wave equation by a discrete time vector finite element method. The popular linear edge basis functions are augmented such that the resulting capacitance matrix is diagonal, resulting in an explicit method. The accuracy and efficiency of the method is investigated via computer experiments. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP White, DA (reprint author), Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. EM dwhite@llnl.gov NR 14 TC 35 Z9 37 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9464 EI 1941-0069 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAY PY 1999 VL 35 IS 3 BP 1458 EP 1461 DI 10.1109/20.767241 PN 1 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 199PM UT WOS:000080490900091 ER PT J AU Shepard, CL Burghard, BJ Friesel, LA Hildebrand, BP Xang, M Diaz, AA Enderlin, CW AF Shepard, CL Burghard, BJ Friesel, LA Hildebrand, BP Xang, M Diaz, AA Enderlin, CW TI Measurements of density and viscosity of one- and two-phase fluids with torsional waveguides SO IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL LA English DT Article ID CONCENTRATED SUSPENSIONS; MIGRATION; SENSOR AB The continuing need for in-situ measurements of physical properties of wastes contained within many high-level radioactive waste tanks within the Hanford Site has initiated experimental and theoretical investigations of candidate measurement methods. This paper describes experiments performed with acoustic waveguide sensors. This technology has potential application at the Hanford Site for in-situ measurements of density, viscosity, and temperature of liquid wastes. Waveguides of both circular and rectangular geometry were used in these studies for determination of the densities and viscosities of various fluids. The flight time of a torsional pulse through the sensing region of the waveguide forms the measured quantity. The flight time depends on the velocity of the wave through the sensing region of the waveguide, and this velocity in turn depends upon the properties of the fluid in contact with the waveguide. We performed experiments with 15 different fluids, most of which were single-phase Newtonian fluids. However, three of the fluids were particle-liquid mixtures, and one of these was non-Newtonian in behavior. Most of the wastes held in Hanford tanks contain high solids content. The results of our experiments showed that acoustic waveguides were well suited for measurements in most Newtonian fluids, in agreement with earlier research presented in the literature. However, results for two-phase Newtonian fluids containing particles indicate that, in our case, the waveguides responded primarily to the background fluid rather than the mixture. Very poor results were obtained with the non-Newtonian fluid. In addition, there was a class of fluids, which serve the community as viscosity standards, for which viscosities determined with torsional waveguides were in disagreement with viscosities obtained with standard viscometers. C1 Pacific NW Lab, Richland, WA 99352 USA. Phys Acoust Corp, Res & Applicat Dept, Lawrenceville, NJ 08648 USA. Intel Corp, Hillsboro, OR 97124 USA. RP Shepard, CL (reprint author), Pacific NW Lab, POB 999, Richland, WA 99352 USA. NR 17 TC 17 Z9 17 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0885-3010 J9 IEEE T ULTRASON FERR JI IEEE Trans. Ultrason. Ferroelectr. Freq. Control PD MAY PY 1999 VL 46 IS 3 BP 536 EP 548 DI 10.1109/58.764840 PG 13 WC Acoustics; Engineering, Electrical & Electronic SC Acoustics; Engineering GA 196WW UT WOS:000080331700008 PM 18238454 ER PT J AU Tsouris, C Borole, AP Kaufman, EN DePaoli, DW AF Tsouris, C Borole, AP Kaufman, EN DePaoli, DW TI An electrically driven gas-liquid-liquid contactor for bioreactor and other applications SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID EMULSION-PHASE CONTACTOR; OIL AB An electrically driven gas-liquid-liquid bioreactor is described here, in which an aqueous medium containing a biocatalyst is introduced as a discontinuous phase into an organic-continuous liquid phase containing a substrate to be converted by the biocatalyst. A gas discontinuous phase, which may be needed to provide oxygen or a gaseous substrate to the biocatalyst, is also introduced into the bioreactor. In contrast to previous work on electrically driven contactors, it was found that the electroconvection generated by the electric field between parallel-plate electrodes may be employed to increase the volume fraction of the discontinuous gas phase in the bioreactor, providing the means for enhanced mass transfer. The electrically driven bioreactor was utilized for oil, desulfurization experiments with Rhodococcus sp. IGTS8 bacteria as the biocatalyst. The organic phase used in the experiments was hexadecane containing dibenzothiophene, a model sulfur compound, that is oxidatively desulfurized to 2-hydroxybiphenyl (2-HBP) by the bacteria in the presence of air or oxygen. The gas volume fraction was increased by 60% by the application of a pulsed electric field, thus providing a means for increased transport of oxygen needed for oxidative desulfurization. The velocity of droplets and bubbles was measured by a phase Doppler velocimeter. The average rising velocity of bubbles was decreased from 13 to less than 3 cm/s and the average horizontal velocity was increased from 0 to 5 cm/s as the field strength was increased from 0 to 4 kV/cm. Desulfurization rates ranged from 1.0 to 5.0 mg of 2-HBP/g of dry cells/h. The desulfurization rate with aeration was doubled under the electric field as compared to the zero-field desulfurization under the same conditions. C1 Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. RP Tsouris, C (reprint author), Oak Ridge Natl Lab, Div Chem Technol, POB 2008, Oak Ridge, TN 37831 USA. RI Borole, AP/F-3933-2011; Tsouris, Costas/C-2544-2016; OI Tsouris, Costas/0000-0002-0522-1027; Borole, Abhijeet/0000-0001-8423-811X NR 18 TC 6 Z9 7 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0888-5885 J9 IND ENG CHEM RES JI Ind. Eng. Chem. Res. PD MAY PY 1999 VL 38 IS 5 BP 1877 EP 1883 DI 10.1021/ie9802515 PG 7 WC Engineering, Chemical SC Engineering GA 194LL UT WOS:000080195000017 ER PT J AU Paglieri, SN Foo, KY Way, JD Collins, JP Harper-Nixon, DL AF Paglieri, SN Foo, KY Way, JD Collins, JP Harper-Nixon, DL TI A new preparation technique for Pd alumina membranes with enhanced high-temperature stability SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID THIN PALLADIUM MEMBRANE; COMPOSITE MEMBRANES; CATALYTIC DEHYDROGENATION; ELECTROLESS DEPOSITION; HYDROGEN SEPARATION; SURFACE ALLOYS; SN/PB SOLDER; REACTORS; PROPANE; METALLIZATION AB Pd/alumina composite membranes were fabricated using the generally practiced electroless plating process involving two-step activation of a symmetric 0.2 mu m alpha-alumina microfilter with tin (Sn) chloride sensitizer (containing SnCl2 and SnCl4) and palladium(II) chloride (PdCl2). Pd films were deposited on these activated supports with a hydrazine- (N2H4-) and PdCl2-containing electroless plating bath. When these membranes were tested at 823 K for several days, the ideal H-2/N-2 separation factor (pure gas permeability ratio) declined substantially, depending on the membrane thickness. Modifications to the activation procedure minimized the amount of Sn chloride used in the sensitizing step. This reduced the selectivity decline, although the problem was not eliminated. The amount of Sn present at the Pd/ceramic interface was qualitatively related to the high-temperature performance. Possible routes for pore formation and selectivity decline are suggested. Sn chloride was removed from the process entirely with a new activation technique utilizing palladium(II) acetate (Pd(O2CCH3)(2)). Prior to electroless plating, substrates were dip-coated in a chloroform solution of Pd acetate, dried, calcined, and then reduced in flowing H-2. At 973 K, nitrogen flux through these membranes remained constant for a period of at least a week. However, hydrogen permeability decreased at 873 K and above because of annealing. C1 Colorado Sch Mines, Dept Chem Engn & Petr Refining, Golden, CO 80401 USA. Sandia Natl Labs, Adv Mat Lab, Albuquerque, NM 87106 USA. RP Way, JD (reprint author), Colorado Sch Mines, Dept Chem Engn & Petr Refining, Golden, CO 80401 USA. NR 50 TC 84 Z9 89 U1 1 U2 17 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0888-5885 J9 IND ENG CHEM RES JI Ind. Eng. Chem. Res. PD MAY PY 1999 VL 38 IS 5 BP 1925 EP 1936 DI 10.1021/ie980199c PG 12 WC Engineering, Chemical SC Engineering GA 194LL UT WOS:000080195000023 ER PT J AU Soong, Y Gamwo, IK Blackwell, AG Harke, FW Ladner, EP AF Soong, Y Gamwo, IK Blackwell, AG Harke, FW Ladner, EP TI Ultrasonic characterizations of slurries in a bubble column reactor SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID 3-PHASE FLUIDIZED-BED; SOLIDS HOLDUP; SUSPENSIONS; PHASE; PROPAGATION AB An indirect method (ultrasonic) and a direct technique were used to measure solid holdup in a bubble-column reactor. Nitrogen, water, and fine glass beads were used as the gas, liquid, and solid phases, respectively. The solid particle concentration in the slurry was varied from 5 to 30 wt %, and the gas superficial velocity was increased from 0.5 to 12 cm/s. The solid holdup measurements by the ultrasonic technique compared reasonably well with results obtained by the direct sampling technique. C1 US DOE, Fed Energy Technol Ctr, Pittsburgh, PA 15236 USA. RP Soong, Y (reprint author), US DOE, Fed Energy Technol Ctr, POB 10940, Pittsburgh, PA 15236 USA. NR 31 TC 7 Z9 8 U1 3 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0888-5885 J9 IND ENG CHEM RES JI Ind. Eng. Chem. Res. PD MAY PY 1999 VL 38 IS 5 BP 2137 EP 2143 DI 10.1021/ie970932k PG 7 WC Engineering, Chemical SC Engineering GA 194LL UT WOS:000080195000046 ER PT J AU Phillpot, SR Keblinski, P Wolf, D Cleri, F AF Phillpot, SR Keblinski, P Wolf, D Cleri, F TI Synthesis and characterization of a polycrystalline ionic thin film by large-scale molecular-dynamics simulation SO INTERFACE SCIENCE LA English DT Article DE polycrystal; ionic; oxide; molecular-dynamics; simulation; growth; thin film; structure; characterization; grain boundary ID TILT GRAIN-BOUNDARIES; FORMATION ENERGIES; OXIDE; NIO; POTENTIALS; DEFECTS; SILICON; DENSE AB A simulation methodology for the synthesis of polycrystalline, ionic thin films is developed. The method involves the preparation of a polycrystalline substrate onto which a thin film is subsequently grown by crystallization from the melt. A detailed structural analysis of a textured sixteen-grain FeO film, with a grain size of approximately 4.7 nm, shows that the interiors of the grains are almost perfect single crystals with only a very few vacancies and no interstitials. The grains are delineated by [001] tilt grain boundaries; as expected, the low-angle grain boundaries in the film consist of arrays of dislocations, while the high-angle grain boundaries are relatively narrow and well ordered. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. ENEA, Ctr Ric Casaccia, Div Mat Avanzati, I-00100 Rome, AD, Italy. EM phillpot@anl.gov RI Phillpot, Simon/J-9117-2012; OI Phillpot, Simon/0000-0002-7774-6535 NR 46 TC 19 Z9 22 U1 0 U2 5 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0927-7056 J9 INTERFACE SCI JI Interface Sci. PD MAY PY 1999 VL 7 IS 1 BP 15 EP 31 DI 10.1023/A:1008782230777 PG 17 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 209KK UT WOS:000081046600002 ER PT J AU Cleri, F Phillpot, SR Wolf, D AF Cleri, F Phillpot, SR Wolf, D TI Atomistic simulations of integranular fracture in symmetric-tilt grain boundaries SO INTERFACE SCIENCE LA English DT Article DE grain-boundary fracture; dislocation nucleation; Peierls-Nabarro model; molecular dynamics simulations ID DISLOCATION NUCLEATION; CRACK TIPS; BEHAVIOR; DUCTILE; CRYSTALS; BRITTLE AB Fracture experiments on symmetric-tilt grain boundaries in Cu are interpreted using the Peierls-Nabarro continuum model of dislocation nucleation as a starting point. Good agreement is found only when the continuum model is modified according to the results of atomistic simulations. The same experiments are also reproduced by direct Molecular Dynamics simulations of fracture propagation and dislocation emission from a microcrack placed in the interface plane of the symmetric-tilt (221)(221) grain boundary in fcc Cu. Direction-dependent fracture response is observed, namely the microcrack advancing by brittle fracture along the [11 (4) over bar] direction and being blunted by dislocation emission along the opposite [(1) over bar (1) over bar 4] direction. Moreover, the simulations allow us to establish important differences with respect to the continuum-model predictions due to the shielding of the stress field at the crack-tip and to the presence of the residual stress at the interface. C1 ENEA, Ctr Ric Casaccia, Div Mat Avanzati, I-00100 Rome, Italy. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. EM cleri@casaccia.enea.it RI Phillpot, Simon/J-9117-2012; OI Phillpot, Simon/0000-0002-7774-6535 NR 24 TC 15 Z9 15 U1 1 U2 12 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0927-7056 J9 INTERFACE SCI JI Interface Sci. PD MAY PY 1999 VL 7 IS 1 BP 45 EP 55 DI 10.1023/A:1008773913030 PG 11 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 209KK UT WOS:000081046600004 ER PT J AU Takasugi, T Liu, CT Heatherly, L Lee, EH George, EP AF Takasugi, T Liu, CT Heatherly, L Lee, EH George, EP TI Influence of grain boundary composition on the moisture-induced embrittlement of Ni-3(Si,Ti) alloys SO INTERMETALLICS LA English DT Article DE silicides, various; environmental embrittlement; interstitial content; control; grain boundaries; structure; spectroscopic methods; various ID LL2-TYPE NI3(SI,TI) INTERMETALLICS; ENVIRONMENTAL EMBRITTLEMENT; MECHANICAL-PROPERTIES; TI) ALLOYS; BORON; NI3AL; NI3SI; TEMPERATURE; FRACTURE; CARBON AB Ni-3(Si,Ti) alloys containing different levels of boron were tensile tested in air at room temperature at two different strain rates. The grain boundary compositions and fracture modes of these alloys were determined by Auger spectroscopy and scanning electron microscopy, respectively. Tensile elongation and fracture mode depend upon the fabrication procedure, heat treatment, and strain rate. Widely different boron concentrations were observed at the grain boundaries, depending on the fabrication procedure and heat treatment. In addition, silicon and titanium were depleted while nickel was enriched at the grain boundaries in all specimens examined. Tensile elongations correlated well with the grain boundary concentration of boron and also with an embrittlement parameter defined as (Si+Ti-B)/Ti. A sharp brittle-ductile transition was found to occur with increasing grain boundary concentration of boron and with decreasing values of the embrittlement parameter (Si+Ti-B)/Ti. The critical grain boundary concentrations corresponding to this transition were found to be sensitive to the strain rate. All the results can be explained in terms of the effect of grain-boundary composition on moisture-induced environmental embrittlement. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Takasugi, T (reprint author), Tohoku Univ, Inst Mat Res, Aoba Ku, Katahira 2-1-1, Sendai, Miyagi 9808577, Japan. RI George, Easo/L-5434-2014 NR 21 TC 6 Z9 6 U1 0 U2 5 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0966-9795 J9 INTERMETALLICS JI Intermetallics PD MAY PY 1999 VL 7 IS 5 BP 543 EP 551 DI 10.1016/S0966-9795(98)00072-7 PG 9 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 185AA UT WOS:000079644900003 ER PT J AU Chu, F Thoma, DJ McClellan, K Peralta, P He, Y AF Chu, F Thoma, DJ McClellan, K Peralta, P He, Y TI Synthesis and properties of MO5Si3 single crystals SO INTERMETALLICS LA English DT Article DE molybdenum silicides; mechanical properties at ambient temperatures; thermal properties; crystal growth ID MOSI2 AB The ultra-high temperature structural intermetallic Mo5Si3 has been studied for alloy processing, physical properties, and mechanical behavior. High purity single crystals of Mo5Si3 have been synthesized by both optical floating zone and Czochralski methods. Structural, thermal, and elastic properties of Mo5Si3 single crystals were measured by X-ray powder diffraction, thermal mechanical analysis, and resonant ultrasound spectroscopy, respectively. Results show that the thermal expansion of MO5Si3, a tetragonal structure with I4/mcm symmetry, is strongly anisotropic along the a and c directions with alpha(c)/alpha(a) = 2.2. Single crystal elastic moduli of Mo5Si3 indicate that it has less elastic anisotropy and lower shear modulus than most transition metal disilicides. The impacts of these physical properties on alloy processing and mechanical behavior are discussed. Room temperature Vickers indentation tests on the (100) and (001) planes have been performed for different orientations of the indenter diagonal and the corresponding hardness, fracture toughness, and deformation behavior have been obtained as a function of the crystallography. Finally, the physical properties and mechanical behavior of Mo5Si3 are compared with those of other high temperature structural silicides, e.g. MoSi2. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Chu, F (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Mail Stop G755, Los Alamos, NM 87545 USA. NR 24 TC 69 Z9 72 U1 2 U2 21 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0966-9795 J9 INTERMETALLICS JI Intermetallics PD MAY PY 1999 VL 7 IS 5 BP 611 EP 620 DI 10.1016/S0966-9795(98)00059-4 PG 10 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 185AA UT WOS:000079644900010 ER PT J AU Sobolev, VN Taylor, LA Snyder, GA Jerde, EA Neal, CR Sobolev, NV AF Sobolev, VN Taylor, LA Snyder, GA Jerde, EA Neal, CR Sobolev, NV TI Quantifying the effects of metasomatism in mantle xenoliths: Constraints from secondary chemistry and mineralogy in Udachnaya Eclogites, Yakutia SO INTERNATIONAL GEOLOGY REVIEW LA English DT Article ID RARE-EARTH ELEMENTS; BENEATH WESTERN VICTORIA; SOUTH-AFRICA; PERIDOTITE XENOLITHS; BELLSBANK KIMBERLITE; OCEANIC CRUSTAL; AQUEOUS FLUIDS; TRACE-ELEMENT; GEOCHEMISTRY; ISOTOPE AB In mantle xenoliths, metasomatism is recorded by compositional variations within and between minerals, and by the introduction of secondary minerals. However, metasomatism has not been quantitatively evaluated as a process with respect to the fluid composition involved. Diamondiferous eclogites from the Udachnaya kimberlite provide a unique suite of samples that allow a semiquantitative estimation of metasomatic fluid composition. The basis of our analysis involves comparison of reconstructed whole-rock compositions with measured whole-rock analyses. Primary minerals in these samples are relatively homogeneous, and permit the use of modal analyses and mineral chemistry for reconstruction of "pristine" whole-rock compositions. The metasomatic overprint. which is similiar in all samples studied, has produced depletions in SiO2, Na2O, and FeO and enrichments in TiO2, K2O, MgO, and LREE. Secondary minerals from the samples are interpreted as the direct result of metasomatism (i.e., typical metasomatic minerals such as phlogopite, amphibole, djerfisherite, and sodalite are present in these xenoliths). Enrichment/depletion signatures demonstrate that the major metasomatic source for Udachnaya eclogites was not derived from the host kimberlite. These metasomatic agents appear to have been more enriched in TiO2, K2O, CI, FeO, and LREE than are kimberlites, and may have contained significant amounts of F, CO2, and H2O. The high Ca contents of two samples are interpreted to be the product of metasomatism by a carbonatite-like fluid. C1 Univ Tennessee, Dept Geol Sci, Planetary Geosci Inst, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37830 USA. Univ Notre Dame, Dept Civil Engn & Geol Sci, Notre Dame, IN 46556 USA. Russian Acad Sci, Siberian Branch, Inst Mineral & Petrog, Novosibirsk 630309, Russia. RP Sobolev, VN (reprint author), Univ Tennessee, Dept Geol Sci, Planetary Geosci Inst, Knoxville, TN 37996 USA. RI Sobolev, Nikolay/A-3850-2014 NR 63 TC 19 Z9 20 U1 1 U2 2 PU V H WINSTON & SON INC PI PALM BEACH PA 360 SOUTH OCEAN BLVD, PH-B, PALM BEACH, FL 33480 USA SN 0020-6814 J9 INT GEOL REV JI Int. Geol. Rev. PD MAY PY 1999 VL 41 IS 5 BP 391 EP 416 PG 26 WC Geology SC Geology GA 195LM UT WOS:000080252400002 ER PT J AU Zauche, TH Espenson, JH AF Zauche, TH Espenson, JH TI Kinetics of oxidation and comproportionation reactions involving an oxammonium ion, benzyl alcohol and methyltrioxorhenium(VII) SO INTERNATIONAL JOURNAL OF CHEMICAL KINETICS LA English DT Article ID METHYLRHENIUM TRIOXIDE; HYDROGEN-PEROXIDE; ALDEHYDES; SYSTEM AB The reactions of 4-hydroxy-2,2,6,6-tetramethylpiperidinium N-oxide, an oxammonium ion abbreviated R2NO+, have been studied. The previously unreported triflate salt was used in this study because the anions of the usual chloride and bromide salts can themselves be oxidized. Reactions between R2NO+ and alcohols produce ketones and aidehydes; the rate constant for PhCH2OH is 4.4 x 10(-3) L mol(-1) s(-1) in acetonitrile at 298 K. The immediate product is the hydroxylamine, R2NOH, but its further comproportionation reaction with R2NO+ yields the stable piperidinyl oxyl radical, R2NO.. The rate constant of this reaction is 1.78 x 10(3) L mol(-1) s(-1) at 298 K. The possibility of using R2NO+ and MTO as co-catalysts for the oxidation of alcohols was explored, but the competitive rates are such that the resultant is not particularly attractive. (C) 1999 John Wiley & Sons, Inc. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP Espenson, JH (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 20 TC 3 Z9 3 U1 0 U2 3 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0538-8066 J9 INT J CHEM KINET JI Int. J. Chem. Kinet. PD MAY PY 1999 VL 31 IS 5 BP 381 EP 385 DI 10.1002/(SICI)1097-4601(1999)31:5<381::AID-KIN7>3.0.CO;2-F PG 5 WC Chemistry, Physical SC Chemistry GA 192XC UT WOS:000080104200007 ER PT J AU Murty, KL Miraglia, PQ Mathew, MD Shah, VN Haggag, FM AF Murty, KL Miraglia, PQ Mathew, MD Shah, VN Haggag, FM TI Characterization of gradients in mechanical properties of SA-533B steel welds using ball indentation SO INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING LA English DT Article DE steel welds; automated ball indentation; stress-strain behavior; energy to fracture AB Gradients in mechanical and fracture properties of SA-533B steel welds were studied using ball indentation technique. The local stress-strain behaviors of different microstructural zones of the weld were determined at various temperatures. Gradients in the strength of the base metal, weld metal and the different positions in the heat affected zone were observed to be consistent with the changes in the microstructure. The maximum in yield and the corresponding minimum in indentation energy to fracture occurred at around 1 mm from the fusion line. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 N Carolina State Univ, Raleigh, NC 27695 USA. Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. Adv Technol Corp, Oak Ridge, TN 37830 USA. RP Murty, KL (reprint author), N Carolina State Univ, Raleigh, NC 27695 USA. NR 11 TC 30 Z9 30 U1 0 U2 9 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0308-0161 J9 INT J PRES VES PIP JI Int. J. Pressure Vessels Pip. PD MAY PY 1999 VL 76 IS 6 BP 361 EP 369 DI 10.1016/S0308-0161(99)00006-X PG 9 WC Engineering, Multidisciplinary; Engineering, Mechanical SC Engineering GA 196WN UT WOS:000080333600004 ER PT J AU Lucas, JN AF Lucas, JN TI Translocation frequencies for low to moderate doses remain constant over time SO INTERNATIONAL JOURNAL OF RADIATION BIOLOGY LA English DT Letter ID RADIATION-INDUCED TRANSLOCATIONS; IN-SITU HYBRIDIZATION; BODY IRRADIATION; PERSISTENCE; STABILITY; WHOLE; DAMAGE C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Lucas, JN (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94551 USA. NR 9 TC 5 Z9 5 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0955-3002 J9 INT J RADIAT BIOL JI Int. J. Radiat. Biol. PD MAY PY 1999 VL 75 IS 5 BP 655 EP 656 PG 2 WC Biology; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 199YM UT WOS:000080511700015 PM 10374948 ER PT J AU Popeko, GS Ter-Akopian, GM Hamilton, J Konnicki, J Daniel, AV Oganessian, YT Ramayya, AV Hwang, JK Sandulescu, A Florescu, A Greiner, W Kliman, J Morch, M Rasmussen, J Stoyer, MA Cole, JD AF Popeko, GS Ter-Akopian, GM Hamilton, J Konnicki, J Daniel, AV Oganessian, YT Ramayya, AV Hwang, JK Sandulescu, A Florescu, A Greiner, W Kliman, J Morch, M Rasmussen, J Stoyer, MA Cole, JD TI Fragment angular momentum and discent dynamics in Cf-252 spontaneous fission SO IZVESTIYA AKADEMII NAUK SERIYA FIZICHESKAYA LA Russian DT Article; Proceedings Paper CT XLVIII International Conference on Nuclear Spectroscopy and on the Nuclear Structure CY JUL 16-19, 1998 CL MOSCOW, RUSSIA C1 Joint Inst Nucl Res, Dubna, Russia. Vanderbilt Univ, Nashville, TN 37235 USA. Joint Inst Heavy Ion Res, Oak Ridge, TN 37831 USA. Inst Theoret Phys, Frankfurt, Germany. Inst Atom Phys, R-76900 Bucharest, Romania. Slovak Acad Sci, Inst Phys, Bratislava, Slovakia. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 95616 USA. Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Popeko, GS (reprint author), Joint Inst Nucl Res, Dubna, Russia. NR 8 TC 0 Z9 0 U1 0 U2 0 PU MEZHDUNARODNAYA KNIGA PI MOSCOW PA 39 DIMITROVA UL., MOSCOW, 113095, RUSSIA SN 1026-3489 J9 IZV AKAD NAUK FIZ+ JI Izv. Akad. Nauk Ser. Fiz. PD MAY PY 1999 VL 63 IS 5 BP 879 EP 882 PG 4 WC Physics, Multidisciplinary SC Physics GA 217RU UT WOS:000081513400005 ER PT J AU L'Eplattenier, P Spielman, RB AF L'Eplattenier, P Spielman, RB TI Double-shell capsule implosion trials on the Z generator of Sandia National Laboratories SO JOURNAL DE PHYSIQUE IV LA French DT Article; Proceedings Paper CT 4th Colloquium on Coherent and Incoherent Sources of UV, VUV and X-Ray Radiation - Applications and Recent Developments CY OCT 06-09, 1998 CL COLLONGES LA ROUGE, FRANCE C1 Ctr Etud Gramat, DT HP, F-46500 Gramat, France. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP L'Eplattenier, P (reprint author), Ctr Etud Gramat, DT HP, F-46500 Gramat, France. NR 1 TC 0 Z9 0 U1 0 U2 1 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 1155-4339 J9 J PHYS IV JI J. Phys. IV PD MAY PY 1999 VL 9 IS P5 BP 39 EP 42 DI 10.1051/jp4:1999514 PG 4 WC Physics, Multidisciplinary SC Physics GA 216XU UT WOS:000081470400015 ER PT J AU Richter, S Alonso, A Wellum, R Taylor, PDP AF Richter, S Alonso, A Wellum, R Taylor, PDP TI The isotopic composition of commercially available uranium chemical reagents SO JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY LA English DT Article AB The uranium isotopic compositions of 12 commercially available uranium chemicals, obtained from various suppliers, were measured by high accuracy isotope mass spectrometry. The goal was to establish the range of isotopic compositions in currently available commercial uranium chemicals, offered in different chemical forms and used for different purposes (e.g., atomic absorption spectrometry or inductively coupled plasma mass spectrometry). The relative isotope abundances of U-234, U-235, U-236 and U-238 were determined by thermal ionisation mass spectrometry with high abundance sensitivity (Finnigan MAT262-RPQ-Plus), using the n(235U)ln(238U) amount ratio measurements of a gravimetrically prepared Isotopic Reference Material (IRMM-183) for mass fractionation correction. All uncertainties were calculated according to the ISO Guide to the Expression of Uncertainty in Measurement (International Standards Organization, Geneva, Switzerland), using a coverage factor k = 2. For n(U-235)/n(U-238) relative uncertainties of 0.2-0.3% and for n(U-234)/n(U-238) and n(U-236)/n(U-238) of 0.4-3.0%, depending on the relative amounts of the U-234 and U-236 isotopes, were achieved. All samples were found to be depleted in U-235 by a factor of two compared with its natural molar abundance (0.72%). The non-natural isotope 236U was present in all samples analyzed. The range found for the molar abundances of U-234 is 0.0022-0.00081%, for U-235 0.35-0.21%, for U-236 0.021-0.000011% and for U-238 99.788-99.634%. C1 Commiss European Communities, Inst Reference Mat & Measurements, JRC, B-2440 Geel, Belgium. RP Richter, S (reprint author), New Brunswick Lab, 9800 S Cass Ave, Argonne, IL 60439 USA. NR 6 TC 9 Z9 9 U1 2 U2 3 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD,, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND SN 0267-9477 J9 J ANAL ATOM SPECTROM JI J. Anal. At. Spectrom. PD MAY PY 1999 VL 14 IS 5 BP 889 EP 891 DI 10.1039/a900774a PG 3 WC Chemistry, Analytical; Spectroscopy SC Chemistry; Spectroscopy GA 198EC UT WOS:000080408900017 ER PT J AU Kwok, TK Zhang, T Chu, PK Bilek, MMM Brown, IG AF Kwok, TK Zhang, T Chu, PK Bilek, MMM Brown, IG TI Computed electron oscillation inside the duct of a vacuum arc source SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID IMMERSION ION-IMPLANTATION; CATHODIC ARC; TRANSPORT; PLASMA; DEPOSITION; COATINGS; FILTERS AB A three-dimensional numerical model has been developed to simulate the motion of electrons inside the duct of a vacuum arc metal source. It is found that electrons will travel back and forth along the center axis inside the duct tube. This phenomenon of electron oscillation can be explained by the combined effects of the electric and magnetic fields. The electron oscillation will increase the charge state of the positive ions and the ions will gain more energy. Due to the influence of electron oscillation, the plasma throughput of the duct will be different from that of a duct under the influence of only the magnetic field. This finding should be taken into account when designing metal arc sources and optimizing their performance. (C) 1999 American Institute of Physics. [S0021-8979(99)05209-3]. C1 City Univ Hong Kong, Dept Phys & Mat Sci, Kowloon, Hong Kong. Univ Cambridge, Dept Engn, Cambridge CB2 1PZ, England. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Chu, PK (reprint author), City Univ Hong Kong, Dept Phys & Mat Sci, 83 Tat Chee Ave, Kowloon, Hong Kong. RI Chu, Paul/B-5923-2013 OI Chu, Paul/0000-0002-5581-4883 NR 18 TC 6 Z9 6 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 1999 VL 85 IS 9 BP 6381 EP 6384 DI 10.1063/1.370103 PG 4 WC Physics, Applied SC Physics GA 188WA UT WOS:000079871200014 ER PT J AU Pike, C Fernandez, A AF Pike, C Fernandez, A TI An investigation of magnetic reversal in submicron-scale Co dots using first order reversal curve diagrams SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB First order reversal curve (FORC) diagrams are a powerful method of investigating the physical mechanisms giving rise to hysteresis in magnetic systems. We have acquired FORC diagrams for an array of submicron-scale Co dots fabricated by interference lithography. These dots reverse magnetization through the nucleation and annihilation of a single-vortex state. Using FORC diagrams, we are able to obtain precise values for the nucleation and annihilation fields involved in magnetic reversal. Our results indicate, however, that there are actually two distinct paths for vortex annihilation: When a complete magnetic reversal takes place, a vortex enters on one side of a dot and exits out the opposite side. But if the magnetization is returned to its original orientation before a complete reversal has occurred, then the vortex will exit on the same side from which it has entered. We are unable to obtain a precise field value for this later path of annihilation; however, it is shown that, statistically, the vortex annihilates with greater ease when it exits out the same side from which it has entered. (C) 1999 American Institute of Physics. [S0021-8979(99)08409-1]. C1 Univ Calif Davis, Dept Geol, Davis, CA 95616 USA. Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Univ Calif Davis, Dept Geol, Davis, CA 95616 USA. EM pike@geology.ucdavis.edu NR 6 TC 65 Z9 66 U1 3 U2 20 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 1999 VL 85 IS 9 BP 6668 EP 6676 DI 10.1063/1.370177 PG 9 WC Physics, Applied SC Physics GA 188WA UT WOS:000079871200061 ER PT J AU Petrik, NG Taylor, DP Orlando, TM AF Petrik, NG Taylor, DP Orlando, TM TI Laser-stimulated luminescence of yttria-stabilized cubic zirconia crystals SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ELECTRICAL-PROPERTIES; TEMPERATURE-DEPENDENCE; DEFECT STRUCTURE; SINGLE-CRYSTALS; THIN-FILMS; ZRO2; PHOTOLUMINESCENCE; CENTERS; DECAY; PHOTOEMISSION AB The kinetics of laser-stimulated luminescence (LSL) of yttria-stabilized cubic zirconia single crystals is investigated. Excitation of ZrO2 . 9.5% Y2O3 (100) and (110) using ns pulses of 213 nm (5.82 eV), 266 nm (4.66 eV), and 355 nm (3.49 eV) photons produce LSL bands with Gaussian profiles and peak maxima at 460 nm (2.69 eV), 550 nm (2.25 eV), and 600 nm (2.07 eV), respectively. LSL involves a single-photon process for energy densities below similar to 1.0 MW/cm(2). Decay times vary from 0.1 to 100 mu s depending on the excitation energy and temperature. Decay kinetics are hyperbolic indicating that all LSL bands result from recombination. The LSL quenches with increasing temperature and activation energies obtained using the Mott approximation are 0.10+/-0.01, 0.20+/-0.02, and 0.45+/-0.04 eV for the 2.69, 2.25, and 2.07 eV LSL bands, respectively. The various activation energies, decay kinetics, and excitation/emission energies correspond to the presence of several emission centers which can be associated with anion vacancies. We tentatively assign these to intrinsic F centers and extrinsic F-type centers. The latter are associated with one and two Y3+ ions in the nearest neighborhood positions. Since the normalized temperature dependencies of the decay coefficients are similar for all the LSL bands, we suggest that recombination primarily involves electrons, trapped at intrinsic and extrinsic defect sites, and mobilized holes. [S0021-8979(99)01709-0]. C1 Pacific NW Lab, WR Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Orlando, TM (reprint author), Pacific NW Lab, WR Wiley Environm Mol Sci Lab, POB 999,MS K8-88, Richland, WA 99352 USA. RI Petrik, Nikolay/G-3267-2015 OI Petrik, Nikolay/0000-0001-7129-0752 NR 60 TC 98 Z9 105 U1 3 U2 14 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 1999 VL 85 IS 9 BP 6770 EP 6776 DI 10.1063/1.370192 PG 7 WC Physics, Applied SC Physics GA 188WA UT WOS:000079871200077 ER PT J AU Perry, MD Stuart, BC Banks, PS Feit, MD Yanovsky, V Rubenchik, AM AF Perry, MD Stuart, BC Banks, PS Feit, MD Yanovsky, V Rubenchik, AM TI Ultrashort-pulse laser machining of dielectric materials SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID GAP OPTICAL-MATERIALS; MULTIPHOTON IONIZATION; IMPACT IONIZATION; INDUCED BREAKDOWN; INDUCED DAMAGE; NANOSECOND; ELECTRONS; SOLIDS; SIO2; FS AB There is a strong deviation from the usual tau(1/2) scaling of laser damage fluence for pulses below 10 ps in dielectric materials. This behavior is a result of the transition from a thermally dominated damage mechanism to one dominated by plasma formation on a time scale too short for significant energy transfer to the lattice. This new mechanism of damage (material removal) is accompanied by a qualitative change in the morphology of the interaction site and essentially no collateral damage. High precision machining of all dielectrics (oxides, fluorides, explosives, teeth, glasses, ceramics, SiC, etc.) with no thermal shock or distortion of the remaining material by this mechanism is described. (C) 1999 American Institute of Physics. [S0021-8979(99)01109-3]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Perry, MD (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-477, Livermore, CA 94550 USA. RI Yanovsky, Victor/B-5899-2008; Feit, Michael/A-4480-2009; Stuart, Brent/K-4988-2015 NR 26 TC 317 Z9 332 U1 8 U2 69 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 1999 VL 85 IS 9 BP 6803 EP 6810 DI 10.1063/1.370197 PG 8 WC Physics, Applied SC Physics GA 188WA UT WOS:000079871200083 ER PT J AU Garcia, E Nedialkov, YA Elliott, J Motin, VL Brubaker, RR AF Garcia, E Nedialkov, YA Elliott, J Motin, VL Brubaker, RR TI Molecular characterization of KatY (Antigen 5), a thermoregulated chromosomally encoded catalase-peroxidase of Yersinia pestis SO JOURNAL OF BACTERIOLOGY LA English DT Article ID LOW-CALCIUM RESPONSE; ESCHERICHIA-COLI; NUCLEOTIDE-SEQUENCE; TRANSCRIPTIONAL ACTIVATOR; MYCOBACTERIUM-TUBERCULOSIS; SALMONELLA-TYPHIMURIUM; ISONIAZID RESISTANCE; MEMBRANE-PROTEINS; OUTER-MEMBRANE; PH-6 ANTIGEN AB The first temperature-dependent proteins (expressed at 37 degrees C, but not 26 degrees C) to be identified in Yersinia pestis were antigens 3 (fraction 1), 4 (pH 6 antigen), and 5 (hereafter termed KatY). Antigens 3 and 4 are now established virulence factors, whereas little is known about KatY, except that it is encoded chromosomally, produced in abundance, possesses modest catalase activity, and is shared by Yersinia pseudotuberculosis, but not Yersinia enteracolitica. We report here an improved chromatographic method (DEAE-cellulose, calcium hydroxylapatite, and Sephadex G-150) that yields enzymatically active KatY (2,423 U/mg of protein). Corresponding mouse monoclonal antibody 1B70.1 detected plasminogen activator-mediated hydrolysis of KatY, and a polyclonal rabbit antiserum raised against outer membranes of Y, pestis was enriched for anti-KatY. A sequenced similar to 16-kb Y. pestis DNA insert of a positive pLG338 clone indicated that katY encodes an 81.4-kDa protein (pI 6.98) containing a leader sequence of 2,6 kDa; the deduced molecular mass and pi of processed KatY were 78.8 kDa and 6.43, respectively. A minor truncated variant (predicted molecular mass of 53.6 kDa) was also expressed. KatY is similar (39 to 59% identity) to vegetative bacterial catalase-peroxidase (KatG in Escherichia coli) and is closely related to plasmid-encoded KatP of enterohemorrhagic E. coli O157:H7 (75% identity). katY encoded a putative Ca2+-binding site, and its promoter contained three homologues to the consensus recognition sequence of the pCD-encoded transcriptional activator LcrF. rbsA was located upstream of katY, and cybB, cybC, dmsABC, and araD were mapped downstream. These genes are not linked to katG or katP in E. coli. C1 Michigan State Univ, Dept Microbiol, E Lansing, MI 48824 USA. Lawrence Livermore Natl Lab, Human Genome Ctr, Livermore, CA 94550 USA. RP Brubaker, RR (reprint author), Michigan State Univ, Dept Microbiol, 57 Giltner Hall, E Lansing, MI 48824 USA. EM brubake3@pilot.msu.edu RI Motin, Vladimir/O-1535-2013 NR 64 TC 36 Z9 42 U1 0 U2 1 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0021-9193 EI 1098-5530 J9 J BACTERIOL JI J. Bacteriol. PD MAY PY 1999 VL 181 IS 10 BP 3114 EP 3122 PG 9 WC Microbiology SC Microbiology GA 197AQ UT WOS:000080342800016 PM 10322012 ER PT J AU Connolly, KM Wojciak, JM Clubb, RT AF Connolly, KM Wojciak, JM Clubb, RT TI Letter to the Editor: Resonance assignments of the Tn916 integrase DNA-binding domain and the integrase : DNA complex SO JOURNAL OF BIOMOLECULAR NMR LA English DT Letter DE integrase; NMR assignments; protein-DNA complex; Tn916 ID NMR C1 Univ Calif Los Angeles, Dept Chem & Biochem, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, OCLA DOE Lab Struct Biol & Genet, Los Angeles, CA 90095 USA. RP Clubb, RT (reprint author), Univ Calif Los Angeles, Dept Chem & Biochem, 405 Hilgard Ave, Los Angeles, CA 90095 USA. FU NIGMS NIH HHS [R01GM57487] NR 10 TC 2 Z9 2 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0925-2738 J9 J BIOMOL NMR JI J. Biomol. NMR PD MAY PY 1999 VL 14 IS 1 BP 95 EP 96 DI 10.1023/A:1008328323180 PG 2 WC Biochemistry & Molecular Biology; Spectroscopy SC Biochemistry & Molecular Biology; Spectroscopy GA 204CE UT WOS:000080744700014 PM 10382314 ER PT J AU Lieu, JG Liu, MJ Frechet, JMJ Prausnitz, JM AF Lieu, JG Liu, MJ Frechet, JMJ Prausnitz, JM TI Vapor-liquid equilibria for dendritic-polymer solutions SO JOURNAL OF CHEMICAL AND ENGINEERING DATA LA English DT Article ID SYSTEMS; DENDRIMERS; SOLVENT; THERMODYNAMICS; BEHAVIOR; TUMORS AB Vapor-liquid equilibria for dendritic-polymer solutions were obtained using a classic gravimetric-sorption method; the amount of solvent absorbed by the dendrimer was measured as a function of solvent vapor pressure. Three series of dendrimers, each with the same tertiary amine core structure, but different surface groups, were investigated in a variety of organic solvents in the range 50-75 degrees C. The dendrimer surface groups were dodecylamines, octadecyl amides, and polyisobutylene. Solvent absorption depends strongly on dendrimer composition and generation number. C1 Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Prausnitz, JM (reprint author), Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. OI Frechet, Jean /0000-0001-6419-0163 NR 23 TC 14 Z9 14 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0021-9568 J9 J CHEM ENG DATA JI J. Chem. Eng. Data PD MAY-JUN PY 1999 VL 44 IS 3 BP 613 EP 620 DI 10.1021/je980214k PG 8 WC Thermodynamics; Chemistry, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA 200DV UT WOS:000080525100047 ER PT J AU Bryan, JC Sachleben, RA Gakh, AA Bunick, GJ AF Bryan, JC Sachleben, RA Gakh, AA Bunick, GJ TI Molecular gears: Structures of (9,10-triptyceno) crown ethers SO JOURNAL OF CHEMICAL CRYSTALLOGRAPHY LA English DT Article DE nanotechnology; molecular devices; triptycene; crown ether; crystal structure; thallium ID CATION-PI INTERACTIONS; X-RAY; CRYSTAL-STRUCTURES; ION SELECTIVITY; MACHINES AB The incorporation of 9,10-triptycene unit in a crown ether is examined from a structural perspective. Insertion of a triptycene group into 18-crown-6 stretches the crown into an ellipse, as seen in structures presented here of 9,10-triptyceno-22-crown-6 and its thallium complex. Symmetric addition of two triptycene groups into 18-crown-6 results in the sterically congested bis(9,10-triptyceno)-26-crown-6, whose crown cavity is filled with the pi-clouds of two arene groups. The larger bis(9,10-triptyceno)-32-crown-8 is more sterically relaxed. The structures of these bis(triptyceno)crown ether molecules are the first with two triptycene groups simultaneously linked through their 9 and 10 positions, thereby forming a simple molecular gearing mechanism. The compound 9,10-triptyceno-22-crown-6 (1) crystallizes in the orthorhombic space group Pbca with a = 10.7962(7), b = 15.826(3), c = 31.147(5) Angstrom, V = 5321.8(12) Angstrom(3), and Z = 8; its complex with TlNO3 (Tl-1) crystallizes in the monoclinic space group P2(1)/c with a = 8.1884(14), b = 19.552(2), c = 20.575(4) Angstrom, beta = 97.062(8)degrees, V = 3269.2(9) Angstrom(3), and Z = 4; bis(9,10-triptyceno)-26-crown-6 (2) crystallizes in the triclinic space group with a = 8.6488(11), b = 10.7718(12), c = 12.3324(12) Angstrom, alpha = 111.58(1), beta = 100.55(1), gamma = 106.43(1)degrees, V = 970.3(5) Angstrom(3), and Z = 1; and bis(9,10-triptyceno)-32-crown-8 (3) crystallizes in the orthorhombic space group Pna2(1) with a = 20.186(3), b = 8.558(2), c = 25.623(2) Angstrom, V = 4426.2(14) Angstrom(3), and Z = 4. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. RP Bryan, JC (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RI G, Neela/H-3016-2014 NR 35 TC 14 Z9 15 U1 1 U2 5 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1074-1542 J9 J CHEM CRYSTALLOGR JI J. Chem. Crystallogr. PD MAY PY 1999 VL 29 IS 5 BP 513 EP 521 DI 10.1023/A:1009535632237 PG 9 WC Crystallography; Spectroscopy SC Crystallography; Spectroscopy GA 259HQ UT WOS:000083888800001 ER PT J AU Wang, XB Ding, CF Wang, LS AF Wang, XB Ding, CF Wang, LS TI High resolution photoelectron spectroscopy of C-60(-) SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ELECTRONIC-STRUCTURE; DOPED C-60; SPECTRA; SUPERCONDUCTIVITY; BUCKMINSTERFULLERENE; PHOTODETACHMENT; PHASE; IONS; C60 AB Vibrationally resolved photoelectron spectra of C-60(-) are reported at three photon energies: 355, 266, and 193 nm. Complicated vibrational structures were observed for the transition to the C-60 ground state with both the A(g) and H-g modes being active. An extra feature was observed in the energy gap region between the highest occupied and lowest unoccupied orbitals of C-60 in the 266 nm spectra only and it was attributed to an autodetachment process. We also report the most accurate measurement of the electron affinity of C-60 (2.689+/-0.008 eV). (C) 1999 American Institute of Physics. [S0021-9606(99)02517-9]. C1 Washington State Univ, Dept Phys, Richland, WA 99352 USA. Pacific NW Natl Lab, WR WIley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Wang, LS (reprint author), Washington State Univ, Dept Phys, 2710 Univ Dr, Richland, WA 99352 USA. NR 25 TC 141 Z9 142 U1 2 U2 17 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 1 PY 1999 VL 110 IS 17 BP 8217 EP 8220 DI 10.1063/1.478732 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 189PD UT WOS:000079913000001 ER PT J AU Wolf, D Keblinski, P Phillpot, SR Eggebrecht, J AF Wolf, D Keblinski, P Phillpot, SR Eggebrecht, J TI Exact method for the simulation of Coulombic systems by spherically truncated, pairwise r(-1) summation SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID COMPUTER-SIMULATION; BOUNDARY-CONDITIONS; LATTICE SUMS; SURFACE; RECONSTRUCTION; ALGORITHM; MGO AB Based on a recent result showing that the net Coulomb potential in condensed ionic systems is rather short ranged, an exact and physically transparent method permitting the evaluation of the Coulomb potential by direct summation over the r(-1) Coulomb pair potential is presented. The key observation is that the problems encountered in determining the Coulomb energy by pairwise, spherically truncated r(-1) summation are a direct consequence of the fact that the system summed over is practically never neutral. A simple method is developed that achieves charge neutralization wherever the r(-1) pair potential is truncated. This enables the extraction of the Coulomb energy, forces, and stresses from a spherically truncated, usually charged environment in a manner that is independent of the grouping of the pair terms. The close connection of our approach with the Ewald method is demonstrated and exploited, providing an efficient method for the simulation of even highly disordered ionic systems by direct, pairwise r(-1) summation with spherical truncation at rather short range, i.e., a method which fully exploits the short-ranged nature of the interactions in ionic systems. The method is validated by simulations of crystals, liquids, and interfacial systems, such as free surfaces and grain boundaries. (C) 1999 American Institute of Physics. [S0021-9606(99)51517-1]. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Wolf, D (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Phillpot, Simon/J-9117-2012 NR 34 TC 553 Z9 557 U1 2 U2 79 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 1 PY 1999 VL 110 IS 17 BP 8254 EP 8282 DI 10.1063/1.478738 PG 29 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 189PD UT WOS:000079913000008 ER PT J AU Huang, YH Hoffman, DK Kouri, DJ AF Huang, YH Hoffman, DK Kouri, DJ TI A minimal subspace residual method for large-scale eigenvalue problems SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SYMMETRIC-MATRICES; NUMERICAL-SOLUTION; ALGORITHM AB We present an iterative method for treating extremely large-scale eigenvalue problems. Based on an exact formula and the GMRES method, our approach generates a subspace which has the property that the residual of interior eigenpairs in the subspace is minimized. The result is that the corresponding large matrix is block-diagonalized iteratively. The accuracy of the final eigenpairs of interest is directly controlled by the accuracy of the GMRES procedure. Our method limits the number of Arnoldi iterations involved, and the dimension of the subspace, by including the residual in the subspace and minimizing it at each step of the iteration. (C) 1999 American Institute of Physics. [S0021-9606(99)01516-0]. C1 Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Univ Houston, Dept Chem, Houston, TX 77204 USA. Univ Houston, Dept Phys, Houston, TX 77204 USA. RP Huang, YH (reprint author), Iowa State Univ, Dept Chem, Ames, IA 50011 USA. NR 19 TC 8 Z9 8 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 1 PY 1999 VL 110 IS 17 BP 8303 EP 8308 DI 10.1063/1.478740 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 189PD UT WOS:000079913000011 ER PT J AU Feller, D Peterson, KA AF Feller, D Peterson, KA TI Re-examination of atomization energies for the Gaussian-2 set of molecules SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID CONFIGURATION-INTERACTION CALCULATIONS; DENSITY-FUNCTIONAL THEORIES; BOND-DISSOCIATION ENERGY; WAVE-FUNCTIONS; BENCHMARK CALCULATIONS; MODEL CHEMISTRY; ELECTRON-AFFINITIES; DIATOMIC-MOLECULES; 2ND-ROW COMPOUNDS; FIRST-ROW AB Atomization energies were computed for 73 molecules, many of them chosen from the GAUSSIAN-2 and G2/97 test sets. A composite theoretical approach was adopted which incorporated estimated complete basis set binding energies based on frozen core coupled cluster theory with a quasiperturbative treatment of triple excitations and three corrections: (1) a coupled cluster core/ valence correction; (2) a configuration interaction scalar relativistic correction; and (3) an atomic spin-orbital correction. A fourth correction, corresponding to more extensive correlation recovery via coupled cluster theory with an approximate treatment of quadruple excitations, was examined in a limited number of cases. For the molecules and basis sets considered in this study, failure to consider any of these contributions to the atomization energy can introduce errors on the order of 1-2 kcal/mol. Although some cancellation of error is common, it is by no means universal and cannot be relied upon for high accuracy. With the largest available basis sets (including, in some cases, up through aug-cc-pV6Z), the mean absolute deviation with respect to experiment was found to lie in the 0.7-0.8 kcal/mol range, neglecting the effects of higher order excitations. Worst case errors were 2-3 kcal/mol. Several complete basis set extrapolations were tested with regard to their effectiveness at improving agreement with experiment, but the statistical difference among the various approaches was small. (C) 1999 American Institute of Physics. [S0021-9606(99)31517-8]. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Washington State Univ, Dept Chem, Pullman, WA 99164 USA. RP Feller, D (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, MS K1-96,POB 999, Richland, WA 99352 USA. NR 94 TC 217 Z9 218 U1 0 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 1 PY 1999 VL 110 IS 17 BP 8384 EP 8396 DI 10.1063/1.478747 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 189PD UT WOS:000079913000019 ER PT J AU Londono, JD Annis, BK Habenschuss, A Smith, GD Borodin, O Tso, C Hsieh, ET Soper, AK AF Londono, JD Annis, BK Habenschuss, A Smith, GD Borodin, O Tso, C Hsieh, ET Soper, AK TI Hydrogen-hydrogen intermolecular structure of polyethylene in the melt SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SATURATED-HYDROCARBON POLYMERS; MOLECULAR-DYNAMICS SIMULATIONS; MOLTEN POLYETHYLENE; NEUTRON-SCATTERING; LOCAL-STRUCTURE; BLENDS; CHAIN; MODEL; THERMODYNAMICS; DIFFRACTION AB Three polyethylene samples, which differed in their degree of deuteration, were studied in neutron diffraction isotopic substitution (NDIS) experiments at 428 K. These results were complemented at small wavevectors by small angle neutron measurements. The intermolecular hydrogen-hydrogen (HH) structure function, h(HH)(Q), was obtained without recourse to intramolecular structure models, as demonstrated in a prior report. The PE experimental results are compared to computer simulation results for the alkanes C100 at 509 K and C44 at 350, 400, and 450 K. The small temperature dependence of the HH intermolecular radial distribution functions, g(HH) (r) for C44 indicates that the differences observed between the PE, C100, and C44 (450 K) results are, for the most part, not due to just temperature differences. It is shown that the string model, an analytic result from an integral equation theory of polymers (PRISM), can account approximately for the overall shape of the g(HH)(r) functions, and that this overall shape is dependent on the radius of gyration of the molecule. Further analysis shows that there are two other contributions to g(HH)(r), both of which are independent of chain length to first order. The first is due to chain-chain packing, and the second is due to local HH intermolecular correlations. These results are significant because they demonstrate that h(HH)(Q) is a useful function for studying intermolecular polymer structure, which has been shown to underpin phase behavior in polyolefin blends. (C) 1999 American Institute of Physics. [S0021-9606(99)51017-9]. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37830 USA. Univ Utah, Dept Mat Sci & Engn, Salt Lake City, UT 84112 USA. Univ Utah, Dept Chem & Fuels Engn, Salt Lake City, UT 84112 USA. Phillips Petr Co, Res & Dev, Bartlesville, OK 74004 USA. Rutherford Appleton Lab, ISIS Sci Div, Didcot OX11 0QX, Oxon, England. RP Annis, BK (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37830 USA. RI Borodin, Oleg/B-6855-2012 OI Borodin, Oleg/0000-0002-9428-5291 NR 39 TC 9 Z9 9 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 1 PY 1999 VL 110 IS 17 BP 8786 EP 8791 DI 10.1063/1.478785 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 189PD UT WOS:000079913000062 ER PT J AU Mosher, JC Baillet, S Leahy, RM AF Mosher, JC Baillet, S Leahy, RM TI EEG source localization and imaging using multiple signal classification approaches SO JOURNAL OF CLINICAL NEUROPHYSIOLOGY LA English DT Article DE source localization; MUSIC (multiple signal classification); image reconstruction; current dipole source models; electroencephalography; magnetoencephalography ID BIOMAGNETIC INVERSE PROBLEM; HUMAN-BRAIN; MEG; MAGNETOENCEPHALOGRAPHY; HEAD; ELECTROENCEPHALOGRAM; POTENTIALS; SPHERES; MODELS; BOUNDS AB Equivalent current dipoles are a powerful tool for modeling focal sources. The dipole is often sufficient to adequately represent sources of measured scalp potentials, even when the area of activation exceeds 1 cm(2) of cortex. Traditional least-squares fitting techniques involve minimization of an error function with respect to the location and orientation of the dipoles. The existence of multiple local minima in this error function can result in gross errors in the computed source locations. The problem is further compounded by the requirement that the model order, i.e. the number of dipoles, be determined before error minimization can be performed. An incorrect model order can produce additional errors in the estimated source parameters. Both of these problems can be avoided using alternative search strategies based on the MUSIC (multiple signal classification) algorithm. Here the authors review the MUSIC approach and demonstrate its application to the localization of multiple current dipoles from EEG data. The authors also show that the number of detectable sources can be determined in a recursive manner from the data. Also, in contrast to least-squares, the method can find dipolar sources in the presence of additional non-dipolar sources. Finally, extensions of the MUSIC approach to allow the modeling of distributed sources are discussed. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ So Calif, Signal & Image Proc Inst, Los Angeles, CA USA. RP Mosher, JC (reprint author), Los Alamos Natl Lab, D454, Los Alamos, NM 87545 USA. FU NIMH NIH HHS [R01-MH53213] NR 48 TC 75 Z9 76 U1 0 U2 5 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0736-0258 J9 J CLIN NEUROPHYSIOL JI J. Clin. Neurophysiol. PD MAY PY 1999 VL 16 IS 3 BP 225 EP 238 DI 10.1097/00004691-199905000-00004 PG 14 WC Clinical Neurology; Neurosciences SC Neurosciences & Neurology GA 212KT UT WOS:000081216400004 PM 10426406 ER PT J AU Broyde, S Hingerty, BE AF Broyde, S Hingerty, BE TI Effective computational strategies for determining structures of carcinogen-damaged DNA SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE molecular mechanics; molecular dynamics; carcinogen-DNA structures ID DEOXYADENOSINE N-6-AMINO GROUP; (+)-ANTI-BENZOPYRENE DIOL EPOXIDE; COVALENTLY ATTACHED BENZOPYRENE; NMR SOLUTION STRUCTURE; DG MISMATCH OPPOSITE; PARTICLE MESH EWALD; SOLUTION CONFORMATION; ADDUCT OPPOSITE; MODIFIED DEOXYGUANOSINE; BASE DISPLACEMENT AB To determine three-dimensional conformations of DNA damaged by environmental chemical carcinogens, effective molecular mechanics search techniques have been developed to deal with the large system sizes and computational demands. First, extensive surveys of the potential energy surface are carried out by energy minimization. These search strategies rely on (1) using the reduced variable domain of torsion-angle (rather than Cartesian) space, (2) building larger units (about 12 base pairs) on the basis of structures of small modified subunits, and (3) employing penalty functions to search for selected hydrogen bonding patterns and to incorporate interproton distance bounds when available from experimental high-resolution nuclear magnetic resonance (NMR) studies. Second, molecular dynamics simulations with solvent can subsequently be employed to probe conformational features in the presence of polymerase enzyme responsible for DNA replication, using structures computed in the energy minimization searches as initial coordinates. A key structure-function relationship involving mirror-image molecules with very differing experimentally determined tumorigenic potencies has been deduced: the members of the pairs align oppositely when bound to DNA, making it likely that their treatment by replication and repair enzymes differ. This opposite orientation phenomenon, first predicted computationally (Singh et al., 1991), has been observed in experimental high-resolution NMR studies combined with our molecular mechanics computations in a number of different examples and has recently been confirmed experimentally in other laboratories as well (reviewed in Geacintov et al., 1997), Elucidation of this conformational feature has paved the way to uncovering the structural origin underlying very different biological outcomes stemming from chemically identical but mirror-image molecules. (C) 1999 Academic Press. C1 NYU, Dept Biol, New York, NY 10003 USA. Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37830 USA. RP Broyde, S (reprint author), NYU, Dept Biol, New York, NY 10003 USA. NR 77 TC 2 Z9 2 U1 0 U2 0 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD MAY 1 PY 1999 VL 151 IS 1 BP 313 EP 332 DI 10.1006/jcph.1998.6172 PG 20 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 194FM UT WOS:000080181500014 ER PT J AU Bodvarsson, GS Boyle, W Patterson, R Williams, D AF Bodvarsson, GS Boyle, W Patterson, R Williams, D TI Overview of scientific investigations at Yucca Mountain - the potential repository for high-level nuclear waste SO JOURNAL OF CONTAMINANT HYDROLOGY LA English DT Article DE Yucca Mountain; radioactive waste; conceptual model; repository safety strategy ID FLOW AB The US Department of Energy (DOE) has been evaluating the unsaturated zone (UZ) at Yucca Mountain, Nevada, as a potential repository site for high level nuclear waste. A large number of boreholes have been drilled at the site, and an underground tunnel, the exploratory studies facility (ESF), has been constructed. A variety of boreholes and underground tests have been conducted that have provided large amounts of data from the UZ. This paper summarizes some of the current knowledge of geological and hydrological characteristics of the site and provides the framework for a series of technical papers that follow in this issue. A brief discussion is also given to the repository safety strategy for Yucca Mountain and the UZ site-scale flow model. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. US Dept Energy, Las Vegas, NV 89109 USA. RP Bodvarsson, GS (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. NR 41 TC 63 Z9 64 U1 2 U2 16 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7722 J9 J CONTAM HYDROL JI J. Contam. Hydrol. PD MAY PY 1999 VL 38 IS 1-3 BP 3 EP 24 DI 10.1016/S0169-7722(99)00009-1 PG 22 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA 203CL UT WOS:000080690000002 ER PT J AU Bandurraga, TM Bodvarsson, GS AF Bandurraga, TM Bodvarsson, GS TI Calibrating hydrogeologic parameters for the 3-D site-scale unsaturated zone model of Yucca Mountain, Nevada SO JOURNAL OF CONTAMINANT HYDROLOGY LA English DT Article DE model calibration; Yucca Mountain; Nevada AB An important issue in the evaluation of the unsaturated zone (UZ) at Yucca Mountain, Nevada is the calibration of the parameters used in the 3-D site-scale numerical flow model. The hydrogeologic parameters are calibrated using an inversion code (ITOUGH2) to fit measured core sample and in situ data according to statistical criteria. The available data include saturations, water potentials, pneumatic pressure records, and pore water age estimates based on geochemical analyses. Five 1-D columns are extracted from the 3-D site-scale model and used in an inversion that matches data from the five boreholes simultaneously. This results in layer-averaged fracture and matrix permeabilities and van Genuchten fitting parameters. The columns are then refined and individual inversions are performed with each I-D model to develop a spatially varying parameter set. A number of sensitivity studies are performed to evaluate the effects of modeling assumptions on the calibrated parameters. Several fracture-matrix interaction formulations are also investigated during the study. The results show that the calibrated parameter set concluded to be most consistent with the conceptual model provides a good fit to the ambient data. The study also shows that the choice of the fracture-matrix interaction formulation has a significant effect on the calibrated parameter set. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Bodvarsson, GS (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. NR 24 TC 39 Z9 39 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7722 J9 J CONTAM HYDROL JI J. Contam. Hydrol. PD MAY PY 1999 VL 38 IS 1-3 BP 25 EP 46 DI 10.1016/S0169-7722(99)00010-8 PG 22 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA 203CL UT WOS:000080690000003 ER PT J AU Ahlers, CF Finsterle, S Bodvarsson, GS AF Ahlers, CF Finsterle, S Bodvarsson, GS TI Characterization and prediction of subsurface pneumatic response at Yucca Mountain, Nevada SO JOURNAL OF CONTAMINANT HYDROLOGY LA English DT Article DE Yucca Mountain; TOUGH2; pneumatic diffusivity; inverse modeling AB Yucca Mountain, Nevada is being investigated as the proposed site for geologic disposal of the United States' high level nuclear waste. A massive effort to collect data for characterization of the thermo-hydrologic behavior of the unsaturated zone is being conducted at the site. Several boreholes have been instrumented by the United States Geological Survey and the Nye County Nuclear Waste Repository Project Office for passive pneumatic monitoring of the subsurface. One-, two- and three-dimensional numerical models are used to simulate the observed subsurface pressure variations. The data are inverted using these models in order to characterize the unsaturated system and estimate the pneumatic diffusivity of important geologic features. Blind predictions of subsurface response and subsequent comparison to recorded data have built confidence in the models of Yucca Mountain. Inversions show that the pneumatic response of the system is dominated by the Paintbrush non-welded unit (PTn). Faults are shown to be fast pathways for gas flow but affect subsurface response only on a relatively local scale. Estimates of the diffusivity of the tuffs that comprise Yucca Mountain range from a low of 0.008 m(2)/s in the non-welded pre-Yucca bedded tuff layer to a high of 4 m(2)/s in the densely welded, fractured Topopah Spring tuff. Estimates of diffusivity in fault zones at Yucca Mountain range between 0.03 m(2)/s and 1500 m(2)/s with the highest being in the Drill Hole Wash fault where it intersects the Topopah Spring tuff. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Nucl Waster Dept, Berkeley, CA 94720 USA. RP Ahlers, CF (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Nucl Waster Dept, Berkeley, CA 94720 USA. RI Finsterle, Stefan/A-8360-2009 OI Finsterle, Stefan/0000-0002-4446-9906 NR 20 TC 33 Z9 34 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7722 J9 J CONTAM HYDROL JI J. Contam. Hydrol. PD MAY PY 1999 VL 38 IS 1-3 BP 47 EP 68 DI 10.1016/S0169-7722(99)00011-X PG 22 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA 203CL UT WOS:000080690000004 ER PT J AU Doughty, C AF Doughty, C TI Investigation of conceptual and numerical approaches for evaluating moisture, gas, chemical, and heat transport in fractured unsaturated rock SO JOURNAL OF CONTAMINANT HYDROLOGY LA English DT Article DE fracture-matrix interaction; vadose-zone hydrology; numerical modeling; dual-permeability; Yucca Mountain; NV ID THERMOHYDROLOGIC CONDITIONS; FLOW; TUFF AB We investigate the utility and appropriateness of various conceptual and numerical approaches for modeling several flow and transport processes in the unsaturated zone (UZ) at Yucca Mountain, NV, using a one-dimensional (I-D) column extracted from a three-dimensional (3-D) UZ site-scale model. Simulations of steady-state and transient moisture flow, transient gas now, tracer transport, and thermal loading scenarios are performed, using a variety of numerical approaches to treat fracture-matrix (F-M) interactions, including an effective continuum model (ECM) and several varieties of dual-continua models. For the dual-continua models, we investigate the effect of varying the number of matrix,gridblocks per fracture gridblock, the formulation applied for calculating F-M interface area, and whether or not global matrix-to-matrix flow occurs (dual-permeability vs. dual-porosity models). The key findings of the work based on a 1-D column are as follows. For steady-state moisture flow, most of the numerical and conceptual models provide similar results for saturation and fracture flow profiles. The ECM adequately models the steady-state processes because the system is not too far away from F-M equilibrium. For both transient moisture flaw and transient transport in a steady flow field, the ECM is not adequate in general. Within the dual-continua models, the formulation for F-M interface area can have a major effect on the hydrodynamic response to an infiltration pulse and tracer arrival at various horizons, with fracture responses becoming earlier as F-M interface area decreases. The number of matrix blocks also has a significant effect on response time, with the more accurate multi-matrix-gridblock models yielding slower fracture response times. For transient gas flow arising from barometric pressure variations, the ECM adequately models the process, because F-M gas flow occurs rapidly compared to the time scale of the barometric pressure variations. For thermal loading, preliminary studies indicate that the ECM does not capture all the significant physical processes, because rapid fluid and heat flow can occur in the fractures before the matrix has a chance to equilibrate. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. EM cadoughty@lbl.gov RI Doughty, Christine/G-2389-2015 NR 37 TC 56 Z9 57 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7722 EI 1873-6009 J9 J CONTAM HYDROL JI J. Contam. Hydrol. PD MAY PY 1999 VL 38 IS 1-3 BP 69 EP 106 DI 10.1016/S0169-7722(99)00012-1 PG 38 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA 203CL UT WOS:000080690000005 ER PT J AU Sonnenthal, EL Bodvarsson, GS AF Sonnenthal, EL Bodvarsson, GS TI Constraints on the hydrology of the unsaturated zone at Yucca Mountain, NV from three-dimensional models of chloride and strontium geochemistry SO JOURNAL OF CONTAMINANT HYDROLOGY LA English DT Article DE chloride; strontium; unsaturated zone; Yucca Mountain; modeling ID NEVADA; USA AB Three-dimensional (3-D) simulations of the spatial and temporal variations in chloride and strontium concentrations in porewaters were performed to constrain infiltration rates, flow paths, and mixing processes in the unsaturated zone (UZ) at Yucca Mountain, NV. Chloride concentrations in infiltrating water were calculated from aerial distributions of precipitation and infiltration rates for the current climatic conditions and for the last glacial maximum, combined with effective chloride concentrations in precipitation. Modeled concentrations are roughly similar to measured porewater chloride concentrations from the Paintbrush nonwelded tuffs in the Exploratory Studies Facility (ESF) tunnel and in boreholes suggesting that the mean infiltration rate over the site is unlikely to be higher than the calculated mean infiltration rate for the modern climate (similar to 5 mm/year; [Flint, A.L., Hevesi, J.A., Flint, L.E., 1996. Conceptual and Numerical Model of Infiltration for the Yucca Mountain Area, Nevada. Milestone 3GU1623M. U.S. Geol. Surv. Water Res. Invest. Rep. U.S. Geological Survey, Denver, CO]). Porewaters from the late Pleistocene (> 10 ka) could be present in the Paintbrush bedded tuffs and in the underlying Topopah Spring welded tuffs (TSw), predominately under regions of thick alluvium having little infiltration. However, porewaters at the potential repository level may have a higher proportion of Holocene recharge due to the higher calculated infiltration rate in this region. Dual-permeability simulations shaw that in low infiltration regions chemical disequilibrium can exist between fracture and matrix porewaters, as a result of the climate change 10,000 years ago. Below the potential repository level, simulations show significant mixing due to lateral flow on top of the low permeability basal vitrophyre in the Topopah Spring unit and on zeolitized tuffs in the Calico Hills unit. Perched water chloride concentrations are closely matched using the calculated conditions for the last glacial maximum climate, with some component of Holocene recharge. Measured strontium concentrations in the UZ and in the perched water bodies can be roughly matched by assuming conservative behavior in nonzeolitic units and strong ion exchange in zeolitic units, and indicate that the perched water bodies are poorly mixed. Differences in the Cl contents of samples having a bomb-pulse Cl-36 signature and those with a modem ratio indicate that waters of intermediate Cl-36/Cl ratios may be mixtures, that without other isotopic data could be inferred as either Pleistocene or Holocene age waters. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, 1 Cyclotron Rd,MS90-1116, Berkeley, CA 94720 USA. EM elsonnenthal@lbl.gov RI Sonnenthal, Eric/A-4336-2009 NR 63 TC 30 Z9 30 U1 1 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7722 EI 1873-6009 J9 J CONTAM HYDROL JI J. Contam. Hydrol. PD MAY PY 1999 VL 38 IS 1-3 BP 107 EP 156 DI 10.1016/S0169-7722(99)00013-3 PG 50 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA 203CL UT WOS:000080690000006 ER PT J AU Wu, YS Ritcey, AC Bodvarsson, GS AF Wu, YS Ritcey, AC Bodvarsson, GS TI A modeling study of perched water phenomena in the unsaturated zone at Yucca Mountain SO JOURNAL OF CONTAMINANT HYDROLOGY LA English DT Article DE perched water; vadose zone hydrology; numerical modeling; unsaturated flow; fractured porous media; Yucca Mountain ID SATURATED FRACTURED TUFF; THERMOHYDROLOGIC CONDITIONS; EQUATION; MEDIA; SOILS; FLOW AB The purpose of this paper is to illustrate the use of a multiphase subsurface flow model to study perched water phenomena in vadose zones. Modeling studies are based on field investigations of the unsaturated zone (UZ) at Yucca Mountain, Nevada. Perched water data have been compiled, analyzed, and incorporated into a three-dimensional (3-D) UZ flow model developed to investigate perched water phenomena at Yucca Mountain. A conceptual model of perched water occurrences is discussed, and a series of comprehensive computer modeling studies on perched water at the site are presented. The model has been calibrated using perched water data observed in six boreholes, and reproduces water-perching conditions in the unsaturated zone of the mountain. Both steady-state and transient simulations have been conducted. The steady-state simulation results are in agreement with the observed perched water data, including water saturation and potential profiles and perched water elevations. Transient numerical pumping tests were performed using pumping testing data collected in the field from two boreholes. The numerical pumping test results match observed water levels collected during pumping and recovery periods. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. EM yswu@lbl.gov RI Wu, Yu-Shu/A-5800-2011 NR 51 TC 18 Z9 18 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7722 EI 1873-6009 J9 J CONTAM HYDROL JI J. Contam. Hydrol. PD MAY PY 1999 VL 38 IS 1-3 BP 157 EP 184 DI 10.1016/S0169-7722(99)00015-7 PG 28 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA 203CL UT WOS:000080690000007 ER PT J AU Wu, YS Haukwa, C Bodvarsson, GS AF Wu, YS Haukwa, C Bodvarsson, GS TI A site-scale model for fluid and heat flow in the unsaturated zone of Yucca Mountain, Nevada SO JOURNAL OF CONTAMINANT HYDROLOGY LA English DT Article DE numerical reservoir simulation; unsaturated zone; Yucca Mountain; site-scale numerical model; multiphase flow; heat transfer ID SATURATED FRACTURED TUFF; THERMOHYDROLOGIC CONDITIONS; POROUS-MEDIA; SIMULATION AB A three-dimensional unsaturated-zone numerical model has been developed to simulate flow and distribution of moisture, gas and heat at Yucca Mountain, Nevada, a potential repository site for high-level radioactive waste. The model takes into account the simultaneous flow dynamics of liquid water, vapor, air and heat in the highly heterogeneous, fractured porous rock in the unsaturated zone (UZ). This model is intended for use in the prediction of the current and future conditions in the UZ so as to aid in the assessment of the system performance of the proposed repository. The modeling approach is based on a mathematical formulation of coupled multiphase, multicomponent fluid and heat flow through porous and fractured rock. Fracture and matrix flow is treated using both dual-permeability and effective-continuum modeling approaches. The model domain covers a total area of approximately 43 km(2), and uses the land surface and the water table as its top and bottom boundaries. In addition, site-specific data, representative surface infiltration, and geothermal conditions are incorporated into the model. The reliability and accuracy of the model have been the subject of a comprehensive model calibration study, in which the model was calibrated against measured data, including liquid saturation, water potential and temperature. It has been found that the model is generally able to reproduce the overall system behavior at Yucca Mountain with respect to moisture profiles, pneumatic pressure variations in different geological units, and ambient geothermal conditions. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. EM yswu@lbl.gov RI Wu, Yu-Shu/A-5800-2011 NR 56 TC 73 Z9 78 U1 1 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7722 EI 1873-6009 J9 J CONTAM HYDROL JI J. Contam. Hydrol. PD MAY PY 1999 VL 38 IS 1-3 BP 185 EP 215 DI 10.1016/S0169-7722(99)00014-5 PG 31 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA 203CL UT WOS:000080690000008 ER PT J AU Haukwa, CB Wu, YS Bodvarsson, GS AF Haukwa, CB Wu, YS Bodvarsson, GS TI Thermal loading studies using the Yucca Mountain unsaturated zone model SO JOURNAL OF CONTAMINANT HYDROLOGY LA English DT Article DE unsaturated zone thermohydrology; repository-flux; effective continuum model (ECM); dual-permeability (dual-k) ID SATURATED FRACTURED TUFF; DRIVEN HYDROTHERMAL FLOW; THERMOHYDROLOGIC CONDITIONS; REPOSITORY AB A systematic modeling study of the effect of thermal loading on moisture, gas, and heat flow in the unsaturated zone of Yucca Mountain has been carried out. The study is based on a two-dimensional (2-D) north-south vertical cross-section, using both the effective continuum and the dual-permeability modeling approaches. A study was also conducted on a three-dimensional (3-D) model using the effective continuum approach. The 2-D model conducted in 1996 uses a average uniform infiltration rate of 4.4 mm/year and a thermal load of 83 kW/acre. The 3-D model uses an spatially varying infiltration rate and a revised average thermal load of 87.6 kW/acre. For the rock properties used in the Topopah Springs (TSw) hydrogeological unit, heat pipe conditions develop above and below the repositary in 10-100 years in both models. The average temperature of the boiling zone is about 96 degrees C. This boiling zone is confined to the TSw hydrogeological unit and lasts about 1000 years. At the top of the CHn (vitric/zeolitic interface), predicted maximum temperature is about 70-75 degrees C after about 2000 years. The model predicts a temperature increase of approximately 30 degrees C at the water table. The results show that thermal loading at the repository also results in significant changes in the moisture distributions at the repository horizon and the zone directly above and below it. A large increase in liquid and gas flux, several orders of magnitude above ambient conditions, is predicted near the repository. This study indicates the ECM and dual-k modeling approaches provide similar simulation results, in terms of temperature and moisture flow and distribution. The only difference is that at early times, the ECM model predicts more extensive boiling conditions. Localized dry-out is predicted in areas with low infiltration flux within the central part of the repository. However, because coarse grids were used, average saturation in the matrix blocks representing the repository indicates will remain high even when the regions near repository are completely dry. Analysis of the flux pattern at the top and bottom boundaries of the repository shows that the liquid always flows into the repository for most the thermal loading period (up to 10,000 years). (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Haukwa, CB (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RI Wu, Yu-Shu/A-5800-2011 NR 52 TC 19 Z9 19 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7722 J9 J CONTAM HYDROL JI J. Contam. Hydrol. PD MAY PY 1999 VL 38 IS 1-3 BP 217 EP 255 DI 10.1016/S0169-7722(99)00016-9 PG 39 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA 203CL UT WOS:000080690000009 ER PT J AU Ritcey, AC Wu, YS AF Ritcey, AC Wu, YS TI Evaluation of the effect of future climate change on the distribution and movement of moisture in the unsaturated zone at Yucca Mountain, NV SO JOURNAL OF CONTAMINANT HYDROLOGY LA English DT Article DE unsaturated-zone; hydrology; climate; modeling ID GREAT-BASIN; CAPILLARY BARRIERS; VEIN CALCITE; DEVILS-HOLE; RECORD; NEVADA AB The objective of this paper is to predict the effect of changes in future climatic conditions on the distribution and movement of moisture in the unsaturated zone (UZ) at Yucca Mountain. Modeling is conducted as part of a continuing effort (Wittwer et al., 1995; Bodvarsson and Bandurraga, 1996; Bodvarsson et al., 1997) using TOUGH2, a multiphase, integrated finite difference numerical model (Pruess, 1991) calibrated using available saturation, water potential and pneumatic data from six boreholes (Bodvarsson et al., 1997). Modeling results indicate that wetter future climatic conditions may increase lateral diversion above low permeability units of the Calico Hills nonwelded (CHn) hydrogeologic unit, and decrease lateral diversion above the Paintbrush nonwelded (PTn) hydrogeologic unit. The existence of lateral diversion above the CHn hydrogeologic unit is important if this diversion allow moisture to bypass altered zeolitic layers where radionuclides potentially released from the repository could be sorbed. Lateral diversion within the PTn hydrogeologic unit is important because it could redistribute the spatial distribution of net infiltration above the repository horizon. Nevertheless, no field evidence of lateral diversion in the PTn unit has been observed, suggesting that faulting or interface heterogeneities limit lateral flow. Collection and analysis of additional,geochemical data may decrease uncertainty in capability of the PTn and altered CHn hydrogeologic units to create barriers to vertical flow, improving confidence in future climatic predictions. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Wu, YS (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RI Wu, Yu-Shu/A-5800-2011 NR 40 TC 8 Z9 8 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7722 J9 J CONTAM HYDROL JI J. Contam. Hydrol. PD MAY PY 1999 VL 38 IS 1-3 BP 257 EP 279 DI 10.1016/S0169-7722(99)00017-0 PG 23 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA 203CL UT WOS:000080690000010 ER PT J AU Pruess, K Faybishenko, B Bodvarsson, GS AF Pruess, K Faybishenko, B Bodvarsson, GS TI Alternative concepts and approaches for modeling flow and transport in thick unsaturated zones of fractured rocks SO JOURNAL OF CONTAMINANT HYDROLOGY LA English DT Review DE fast preferential flow; conceptual models; numerical simulation; robust performance assessment ID WETTING FRONT INSTABILITY; LATTICE-GAS AUTOMATA; POROUS-MEDIA; HETEROGENEOUS SOILS; STOCHASTIC-ANALYSIS; RELATIVE PERMEABILITY; INVASION PERCOLATION; FRACTAL DIMENSION; SOLUTE TRANSPORT; STRATIFIED SOILS AB There is growing evidence that water seepage in thick unsaturated zones in fractured rocks may occur in non-volume-averaged fashion, as relatively 'slow' flow in the rock matrix, and 'fast' flow along localized preferential pathways in fractures. This poses difficult challenges for mathematical modeling. We summarize recent field observations of subsurface flow and transport from semi-arid regions, discuss alternative approaches for modeling fast preferential flow, and evaluate prospects for resolving current uncertainties. It is concluded that modeling of flow in fractured unsaturated zones is complex, but feasible, while modeling of transport processes is more difficult and less certain. We emphasize that successful modeling requires clear and specific objectives, but does not necessarily require a complete and detailed understanding of all processes and properties of a system. In order to achieve a robust modeling capability, as needed for engineering assessment and design of waste containment systems, it is suggested that two or more alternative modeling approaches be developed simultaneously for a given site. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Pruess, K (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RI Faybishenko, Boris/G-3363-2015 OI Faybishenko, Boris/0000-0003-0085-8499 NR 171 TC 58 Z9 63 U1 1 U2 15 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7722 J9 J CONTAM HYDROL JI J. Contam. Hydrol. PD MAY PY 1999 VL 38 IS 1-3 BP 281 EP 322 DI 10.1016/S0169-7722(99)00018-2 PG 42 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA 203CL UT WOS:000080690000011 ER PT J AU Wang, JSY Trautz, RC Cook, PJ Finsterle, S James, AL Birkholzer, J AF Wang, JSY Trautz, RC Cook, PJ Finsterle, S James, AL Birkholzer, J TI Field tests and model analyses of seepage into drift SO JOURNAL OF CONTAMINANT HYDROLOGY LA English DT Article DE drift seepage; capillary barrier; fracture flow paths; tracer tests; air permeability; Yucca Mountain ID EXCLUSION PROBLEM; CYLINDRICAL CAVITIES; CAPILLARY BARRIERS; POROUS-MEDIA; FLUID; FLOW AB This paper focuses on field test results and model analyses of the first set of five niche seepage tests conducted in the Exploratory Studies Facility at Yucca Mountain. The test results suggest that (1) a niche opening (short drift excavated for this study) acts as a capillary barrier; (2) a seepage threshold exists; and (3) the seepage is a fraction of the liquid released above the ceiling. Before seepage quantification, air injection and liquid release tests at two niche locations were conducted to characterize the fracture flow paths. Nearly two-order-af-magnitude changes in air permeability values were measured before and after niche excavation. The dyed liquid flow paths, together with a localized wet feature potentially associated with an ambient flow path, were mapped during dry excavation operations. After niche excavation, the seepage is quantified by the ratio of the water mass dripped into a niche to the mass released above the opening at selected borehole intervals. For the first set of five tests conducted at Niche 3650 site, the ratios range from 0% (no dripping for two tests) to 27.2%. Changes in flow path distributions and water accumulation near seepage threshold were observed on the niche ceiling. The seepage test results compare reasonably well with model results without parameter adjustments, using capillary barrier boundary condition in the niche and two-dimensional and three-dimensional conceptualizations to represent discrete fracture and fracture network for the flow paths. Model analyses of the niche tests indicate that the seepage is very sensitive to the niche boundary condition and is moderately sensitive to the heterogeneity of the fracture flow paths and to the strengths of matrix imbibition. Strong capillary strength and large storage capacity of the fracture flow paths limit the seepage. High permeability value also enhances diversion and reduces seepage for low liquid release rate. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Wang, JSY (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, MS 90-1116,1 Cyclotron Rd, Berkeley, CA 94720 USA. RI Birkholzer, Jens/C-6783-2011; Finsterle, Stefan/A-8360-2009; James, April/D-1415-2012 OI Birkholzer, Jens/0000-0002-7989-1912; Finsterle, Stefan/0000-0002-4446-9906; NR 24 TC 44 Z9 47 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7722 J9 J CONTAM HYDROL JI J. Contam. Hydrol. PD MAY PY 1999 VL 38 IS 1-3 BP 323 EP 347 DI 10.1016/S0169-7722(99)00019-4 PG 25 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA 203CL UT WOS:000080690000012 ER PT J AU Birkholzer, J Li, GM Tsang, CF Tsang, Y AF Birkholzer, J Li, GM Tsang, CF Tsang, Y TI Modeling studies and analysis of seepage into drifts at Yucca mountain SO JOURNAL OF CONTAMINANT HYDROLOGY LA English DT Article DE unsaturated flow; drift seepage; heterogeneity; fractured tuff; Yucca Mountain; Nevada ID EXCLUSION PROBLEM; UNSATURATED FLOW; HETEROGENEOUS SOILS; STOCHASTIC-ANALYSIS; HYDRAULIC CONDUCTIVITY; CYLINDRICAL CAVITIES; CAPILLARY BARRIERS; POROUS-MEDIA AB An important issue for the long-term performance of underground nuclear waste repositories is the rate of water seepage into the waste emplacement drifts. A prediction of the seepage rate is particularly complicated for the potential repository site at Yucca Mountain, NV, which is located in a thick sequence of unsaturated, fractured tuffs. Underground openings in unsaturated media might act as capillary barriers, diverting water around them. In the present work, we study the potential rates of seepage into drifts as a function of predicted percolation flux at Yucca Mountain, based on a stochastic model of the fractured rock mass in the drift vicinity. A variety of now scenarios are considered, assuming estimated present-day and predicted future climate conditions. We show that the heterogeneity in the flow domain is a key factor controlling seepage rates, since it causes channelized flow and local pending in the unsaturated flow field. The rates of seepage are related in a complex non-linear manner to the rock properties, the size and shape of the drift, the degree of heterogeneity, and the assumed percolation scenario. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Lawrence Berkeley Lab, ESD, Berkeley, CA 94720 USA. RP Tsang, CF (reprint author), Lawrence Berkeley Lab, ESD, Berkeley, CA 94720 USA. RI Birkholzer, Jens/C-6783-2011 OI Birkholzer, Jens/0000-0002-7989-1912 NR 36 TC 43 Z9 47 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7722 J9 J CONTAM HYDROL JI J. Contam. Hydrol. PD MAY PY 1999 VL 38 IS 1-3 BP 349 EP 384 DI 10.1016/S0169-7722(99)00020-0 PG 36 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA 203CL UT WOS:000080690000013 ER PT J AU Tsang, YW Birkholzer, JT AF Tsang, YW Birkholzer, JT TI Predictions and observations of the thermal-hydrological conditions in the Single Heater Test SO JOURNAL OF CONTAMINANT HYDROLOGY LA English DT Article DE thermal; hydrological; fractured rock; field test; Yucca Mountain; Nevada ID DRIVEN HYDROTHERMAL FLOW; SATURATED FRACTURED TUFF; HYDRAULIC CONDUCTIVITY; YUCCA MOUNTAIN; REPOSITORY AB The Single Heater Test (SHT) is one of two in-situ thermal tests included in the site characterization program for the potential underground nuclear waste repository at Yucca Mountain. Coupled thermal-hydrological-mechanical-chemical processes in the fractured rock mass around the heater were monitored by numerous sensors emplaced among 30 boreholes. Periodic active testing of cross-hole radar tomography, neutron logging, electrical resistivity tomography, and interference air permeability tests probed the change of moisture content in the rock mass. Thermal-hydrological processes in the SHT have been simulated using a 3-D numerical model and compared to the monitored data. The good agreement between the temperature data and simulated results indicates that the thermal-hydrological responses of the SHT in the 9 months of heating are well-represented by the coupled thermal-hydrological numerical model. The dominant heat transfer process is by conduction and the signature of vapor and liquid counter flow is subtle in the temperature data. The simulated result of a dry-out zone of about 1 m (at the end of the heating phase) around the heater hole, and a condensation zone of increased liquid saturation outside of the dry-out zone, is consistent with the radar tomography and air permeability data. Tomography data and post-test laboratory measurements indicate that the moisture content is larger below than above the heater horizon, suggesting gravity drainage of condensate in the fractures. Model studies show that gravity drainage occurs in simulations using the dual permeability conceptual model, but is absent in the effective-continuum model, where matrix and fractures are required to be in thermodynamic equilibrium at all times. (C) 1999 Elsevier Science B.V. Ail rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Tsang, YW (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RI Birkholzer, Jens/C-6783-2011 OI Birkholzer, Jens/0000-0002-7989-1912 NR 38 TC 36 Z9 37 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7722 J9 J CONTAM HYDROL JI J. Contam. Hydrol. PD MAY PY 1999 VL 38 IS 1-3 BP 385 EP 425 DI 10.1016/S0169-7722(99)00021-2 PG 41 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA 203CL UT WOS:000080690000014 ER PT J AU Reid, JW Strayer, DL McArthur, JV Stibbe, SE Lewis, JJ AF Reid, JW Strayer, DL McArthur, JV Stibbe, SE Lewis, JJ TI Rheocyclops, a new genus of copepods from the southeastern and central USA (Copepoda : Cyclopoida : Cyclopidae) SO JOURNAL OF CRUSTACEAN BIOLOGY LA English DT Article AB The new genus Rheocyclops is proposed to accommodate the cyclopoid copepods Diacyclops virginianus Reid, from Virginia, and the new species R. carolinianus from South Carolina, R. talladega and R. hatchiensis ham Alabama, and R. indiana from indiana, U.S.A. Most species were collected from the hyporheic zones of stream beds, except R. indiana which was found in a drip pool in a cave. The new genus is distinguished by a combination of characters: anal operculum produced; antennule 11-segmented; antenna lacking exopodite seta; rami of legs 1-4 all 3-segmented, pr some rami 2-segmented; leg 5 with proximal segment fused to somite and reduced to small protrusion bearing seta inserted near distal (free) segment, and free segment cylindrical with 2 terminal setae. C1 Smithsonian Inst, Natl Museum Amer Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. Inst Ecosyst Studies, Millbrook, NY 12545 USA. Univ Georgia, Savannah River Ecol Lab, Aiken, SC 29802 USA. RP Reid, JW (reprint author), Smithsonian Inst, Natl Museum Amer Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. RI Strayer, David/H-3788-2011 NR 27 TC 15 Z9 15 U1 0 U2 0 PU CRUSTACEAN SOC PI SAN ANTONIO PA 840 EAST MULBERRY, SAN ANTONIO, TX 78212 USA SN 0278-0372 J9 J CRUSTACEAN BIOL JI J. Crustac. Biol. PD MAY PY 1999 VL 19 IS 2 BP 384 EP 396 DI 10.2307/1549246 PG 13 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 196GC UT WOS:000080299800020 ER PT J AU Williamson, AJ Franceschetti, A Fu, H Wang, LW Zunger, A AF Williamson, AJ Franceschetti, A Fu, H Wang, LW Zunger, A TI Indirect band gaps in quantum dots made from direct-gap bulk materials SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT 40th Electronic Materials Conference (EMC-40) CY JUN 24-26, 1998 CL UNIV VIRGINIA, CHARLOTTESVILLE, VIRGINIA SP TMS HO UNIV VIRGINIA DE heterostructures; nanostructures; quantum dots ID BEAM EPITAXIAL-GROWTH; ELECTRONIC-STRUCTURE; SEMICONDUCTOR DOTS; INAS; TRANSITION; DENSITY; ISLANDS; ENERGY; STATE; GAAS AB The conditions under which the band gaps of free standing and embedded semiconductor quantum dots are director indirect are discussed. Semiconductor quantum dots are classified into three categories; (i) free standing dots, (ii) dots embedded in a direct gap matrix, and (iii) dots embedded in an indirect gap matrix. For each category, qualitative predictions are first discussed, followed by the results of both recent experiments and state of the art pseudopotential calculations. We show that: Free standing dots of InP, InAs, and CdSe will remain direct for all sizes, while dots made of GaAs and InSb will turn indirect below a critical size. Dots embedded within a direct gap matrix material will either stay direct (InAs/GaAs at zero pressure) or will become indirect at a critical size (InSb/InP). Dots embedded within an indirect gap matrix material will exhibit a transition to indirect gap for sufficiently small dots (GaAs/AlAs and InP/GaP quantum well) or will be always indirect (InP/GaP dots, InAs/GaAs above 43 kbar pressure and GeSi/Si dots). In indirect nanostructures, charge separation can occur with electrons and holes localized on different materials (flat InP/GaP quantum well) or with electrons and holes localized in different layers of the same material(concentric cylindrical GaAs/A1As layers). C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Williamson, AJ (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Zunger, Alex/A-6733-2013 NR 50 TC 20 Z9 20 U1 0 U2 13 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 USA SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD MAY PY 1999 VL 28 IS 5 BP 414 EP 425 DI 10.1007/s11664-999-0089-8 PG 12 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA 195UC UT WOS:000080269700004 ER PT J AU Lee, H Yang, WD Sercel, PC Norman, AG AF Lee, H Yang, WD Sercel, PC Norman, AG TI The shape of self-assembled InAs islands grown by molecular beam epitaxy SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT 40th Electronic Materials Conference (EMC-40) CY JUN 24-26, 1998 CL UNIV VIRGINIA, CHARLOTTESVILLE, VIRGINIA SP TMS HO UNIV VIRGINIA DE {136} facets; atomic force microscopy (AFM); cross-section transmission electron microscopy (TEM); InAs quantum dot shape; polarization-resolved photoluminescence (PL); reflection high energy electron diffraction (RHEED) ID INAS/GAAS QUANTUM DOTS; TRANSMISSION-ELECTRON-MICROSCOPY; STRAIN DISTRIBUTION; GAAS; PHOTOLUMINESCENCE; DIFFRACTION; GE; SUPERLATTICES; TEMPERATURE; DEPENDENCE AB We have determined the shape of InAs quantum dots using reflection high energy electron diffraction. Our results indicate that self-assembled InAs islands possess a pyramidal shape with {136} bounding facets. This shape is characterized by C-2 upsilon symmetry and a parallelogram base, which is elongated along the [1(1) over bar 0] direction. Cross-sectional transmission electron microscopy images taken along the [110] and [1(1) over bar 0] directions as well as atomic force microscopy images strongly support the {136} shape. Furthermore, polarization-resolved photoluminescence spectra show-strong in-plane anisotropy, with emission predominantly polarized along the [1(1) over bar 0] direction, consistent with the proposed quantum dot shape. C1 Univ Oregon, Inst Mat Sci, Dept Phys, Eugene, OR 97403 USA. Univ Oregon, Oregon Ctr Opt, Eugene, OR 97403 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Lee, H (reprint author), Univ Oregon, Inst Mat Sci, Dept Phys, Eugene, OR 97403 USA. RI Norman, Andrew/F-1859-2010 OI Norman, Andrew/0000-0001-6368-521X NR 38 TC 13 Z9 13 U1 0 U2 1 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 USA SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD MAY PY 1999 VL 28 IS 5 BP 481 EP 485 DI 10.1007/s11664-999-0098-7 PG 5 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA 195UC UT WOS:000080269700013 ER PT J AU Paulino, GH Gray, LJ AF Paulino, GH Gray, LJ TI Galerkin residuals for adaptive symmetric-Galerkin boundary element methods SO JOURNAL OF ENGINEERING MECHANICS-ASCE LA English DT Article ID MESH REFINEMENT; HYPERSINGULAR INTEGRALS; LINEAR ELASTICITY; ERROR INDICATORS; H-VERSION; P-VERSION; FORMULATION; EQUATIONS; SENSITIVITIES; BEM AB This paper presents a simple a posteriori error estimator and an effective adaptive mesh refinement procedure for the symmetric Galerkin boundary element method. The "hypersingular residuals," developed for error estimation in a standard collocation BEM; are extended to the symmetric Galerkin setting. This leads to the formulation of "Galerkin residuals," which are intrinsic to the symmetric Galerkin boundary integral approach and form the basis of the present error estimation scheme. Several computational experiments are conducted to test both the accuracy and the reliability of the proposed technique. These experiments involve potential theory and various problem configurations including mixed boundary conditions, corners, and nonconvex domains. The numerical results indicate that reliable solutions to practical engineering problems can be obtained with this method. C1 Univ Illinois, Dept Civil & Environm Engn, Urbana, IL 61801 USA. Oak Ridge Natl Lab, Math Sci Sect, Div Math & Comp Sci, Oak Ridge, TN 37831 USA. RP Paulino, GH (reprint author), Univ Illinois, Dept Civil & Environm Engn, Urbana, IL 61801 USA. RI Paulino, Glaucio/A-2426-2008 NR 57 TC 21 Z9 21 U1 0 U2 0 PU ASCE-AMER SOC CIVIL ENGINEERS PI RESTON PA 1801 ALEXANDER BELL DR, RESTON, VA 20191-4400 USA SN 0733-9399 J9 J ENG MECH-ASCE JI J. Eng. Mech.-ASCE PD MAY PY 1999 VL 125 IS 5 BP 575 EP 585 DI 10.1061/(ASCE)0733-9399(1999)125:5(575) PG 11 WC Engineering, Mechanical SC Engineering GA 188PY UT WOS:000079858300011 ER PT J AU Siegrist, RL Lowe, KS Murdoch, LC Case, TL Pickering, DA AF Siegrist, RL Lowe, KS Murdoch, LC Case, TL Pickering, DA TI In situ oxidation by fracture emplaced reactive solids SO JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE LA English DT Article ID ZERO-VALENT IRON; FIELD EXPERIMENTS; REMOVAL; ELECTROOSMOSIS; CONTAMINANTS; REMEDIATION; REDUCTION; METAL; SOILS; MEDIA AB In low permeability but naturally fractured media. vertical leaching or volatilization of toxic organic compounds can lead to high exposures and unacceptable human health or environmental risk. A field test was recently completed to evaluate in situ remediation at such sites by using hydraulic fracturing to emplace iron metal (Fe-0) and permanganate (KMnO4) solids in the subsurface to chemically treat trichloroethylene (TCE). At an old land treatment site, two test cells were installed in silty day soils with hydraulic fractures filled with either iron metal or permanganate solids at 1.8, 2.4, and 3.6 m depths. Fracture emplacement was monitored, and soil and ground water conditions were characterized. After 3, 10, and 15 mo of emplacement, continuous cores were collected and morphologic and geochemical data were taken across the fracture zones. Controlled degradation tests were completed using site ground water with TCE concentrations near 53, 144, and 480 mg/L, equivalent to 0.5, 1.2, and 4.1 g TCE per kg media, respectively. The iron-filled fractures formed a discrete reactive seam less than 1 cm thick, wherein the Eh decreased and reductive dechlorination could occur, but effects in the adjacent silty clay soils were negligible. Though the emplaced iron exhibited some surface corrosion after extended emplacement in the subsurface, its reactivity was unaffected. Iron from the fractures degraded TCE at efficiencies of as much as 36% after 24-48 ht of contact, which is consistent with Fe-0 packed bed degradation half-lives of 1 to 2 hr. The permanganate-filled fractures yielded a diffuse reactive zone that expanded over time, reaching 40 cm in thickness after 10 mo. Throughout this oxidizing zone, the degradation efficiency was >99% after 2 hr of contact for dissolved TCE at 0.5 and 1.2 mg TCE per g of media. When exposed to higher TCE loadings (i.e., 4.1 mg per g), degradation efficiencies after 10 mo dropped to 70% as the TCE load exceeded the oxidant capacity remaining. These efficiencies and rates are consistent with oxidation stoichiometry and previously determined half-lives of <2 min for permanganate oxidation of TCE. In both test cells there were no marked effects on the chemistry or contamination levels in the ground water beneath the cells. Though the results of this research are promising for emplacement of horizontal treatment zones, further work is required to support full-scale application. C1 Colorado Sch Mines, Oak Ridge Natl Lab, Envir Sci & Engn Div, Golden, CO 80401 USA. Clemson Univ, Dept Geosci, Clemson, SC 29634 USA. Am Water Works Assoc Res Found, Denver, CO 80235 USA. Oak Ridge Natl Lab, Div Life Sci, Grand Junction, CO USA. RP Siegrist, RL (reprint author), Colorado Sch Mines, Oak Ridge Natl Lab, Envir Sci & Engn Div, Coolbaugh Hall, Golden, CO 80401 USA. NR 36 TC 56 Z9 56 U1 1 U2 15 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 USA SN 0733-9372 J9 J ENVIRON ENG-ASCE JI J. Environ. Eng.-ASCE PD MAY PY 1999 VL 125 IS 5 BP 429 EP 440 DI 10.1061/(ASCE)0733-9372(1999)125:5(429) PG 12 WC Engineering, Environmental; Engineering, Civil; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 188RE UT WOS:000079861600006 ER PT J AU Johnson, KN Agee, J Beschta, R Dale, V Hardesty, L Long, J Nielsen, L Noon, B Sedjo, R Shannon, M Trosper, R Wilkinson, C Wondolleck, J AF Johnson, KN Agee, J Beschta, R Dale, V Hardesty, L Long, J Nielsen, L Noon, B Sedjo, R Shannon, M Trosper, R Wilkinson, C Wondolleck, J TI Sustaining the people's lands - Recommendations for stewardship of the national forests and grasslands into the next century SO JOURNAL OF FORESTRY LA English DT Article AB in December 1997, Secretary of Agriculture Dan Glickman convened an interdisciplinary committee of 13 scientists to provide scientific and technical advice on the Forest Service's land and resource management planning process. The committee was asked to recommend how best to accomplish resource planning within the existing:environmental laws and statutory mission of the Forest Service; to provide technical advice on planning and provide material for the agency to consider in revising planning regulations;to recommend improvements in coordination with other federal agencies, state and local government agencies. and tribal governments; and to suggest a new planning framework that could last a generation. The committee rook field trips and met in cities and towns around the country to hear from Forest Service employees, representatives of tribes, state and local governments, related federal natural resource agencies, and members of the public. Drawing on many of the approaches and improvements to planning it observed, the committee has made its recommendations. C1 Oregon State Univ, Coll Forestry, Corvallis, OR 97331 USA. Univ Washington, Seattle, WA 98195 USA. Oak Ridge Natl Lab, Oak Ridge, TN USA. Washington State Univ, Pullman, WA 99164 USA. Utah State Univ, Logan, UT 84322 USA. Penn State Univ, University Pk, PA 16802 USA. Colorado State Univ, Ft Collins, CO 80523 USA. Resources Future Inc, Washington, DC 20036 USA. Buffalo Sch Law, Buffalo, NY USA. No Arizona Univ, Flagstaff, AZ 86011 USA. Univ Colorado, Boulder, CO 80309 USA. Univ Michigan, Ann Arbor, MI 48109 USA. RP Johnson, KN (reprint author), Oregon State Univ, Coll Forestry, Corvallis, OR 97331 USA. RI Dale, Virginia/B-6023-2009 NR 0 TC 15 Z9 17 U1 0 U2 2 PU SOC AMER FORESTERS PI BETHESDA PA 5400 GROSVENOR LANE, BETHESDA, MD 20814 USA SN 0022-1201 J9 J FOREST JI J. For. PD MAY PY 1999 VL 97 IS 5 BP 6 EP 12 PG 7 WC Forestry SC Forestry GA 192BZ UT WOS:000080059500004 ER PT J AU Riley, P Gosling, JT McComas, DJ Pizzo, VJ Luhmann, JG Biesecker, D Forsyth, RJ Hoeksema, JT Lecinski, A Thompson, BJ AF Riley, P Gosling, JT McComas, DJ Pizzo, VJ Luhmann, JG Biesecker, D Forsyth, RJ Hoeksema, JT Lecinski, A Thompson, BJ TI Relationship between Ulysses plasma observations and solar observations during the Whole Sun Month campaign SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID HELIOSPHERIC CURRENT SHEET; WIND VARIABILITY; LATITUDES; MISSION; STREAM; MODELS; BAND AB In this report, we summarize measurements made by the plasma experiment on the Ulysses spacecraft during the period designated as "Whole Sun Month" (WSM, August 10 to September 8; 1996). This interval coincided with the return of solar wind variability at Ulysses. Ulysses was located at similar to 28 degrees N heliographic latitude, at a heliocentric distance of 4.25 AU, and on the opposite side of the Sun from Earth. In particular: we explore the evolution of the solar wind between the Sun and Ulysses for several rotations surrounding WSM. Specifically, we map Ulysses measurements back toward the Sun by applying a two-dimensional inverse MHD algorithm. This approach is compared with the commonly used constant speed (or ballistic) approximation. We find that the MHD mapping technique produces substantially better results when compared with solar observations. Both the Ulysses MHD-mapped results and the solar observations are consistent with a picture of a modestly tilted streamer belt (< 10 degrees) that was deformed northward by an active region at 240 degrees - 270 degrees longitude. C1 ScriberNet Inc, San Diego, CA 92121 USA. Univ Calif Los Alamos Natl Lab, Space & Atmospher Sci Grp, Los Alamos, NM 87545 USA. NOAA, Space Environm Lab, Boulder, CO 80303 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Birmingham, Sch Phys & Space Res, Birmingham B15 2TT, W Midlands, England. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London SW7 2BZ, England. Stanford Univ, Wilcox Solar Observ, Ctr Astrophys & Space Sci, Hansen Expt Phys Lab, Stanford, CA 94305 USA. Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Riley, P (reprint author), Sci Applicat Int Corp, San Diego, CA 92121 USA. RI Thompson, Barbara/C-9429-2012 NR 23 TC 23 Z9 23 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1999 VL 104 IS A5 BP 9871 EP 9879 DI 10.1029/1998JA900078 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 192BQ UT WOS:000080058600017 ER PT J AU Kahler, SW Crooker, NU Gosling, JT AF Kahler, SW Crooker, NU Gosling, JT TI A magnetic polarity and chirality analysis of ISEE 3 interplanetary magnetic clouds SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID CORONAL MASS EJECTIONS; SECTOR BOUNDARIES; SOLAR-WIND; FIELDS; ELECTRONS; AU AB We have used solar wind electron heat fluxes to determine the magnetic polarities of the 14 magnetic clouds observed with the ISEE 3 spacecraft in 1978-1982. The clouds have been modeled as single magnetic flux ropes, and it is generally assumed that they are magnetically closed structures with each end of the flux rope connected to the Sun. In that case, the magnetic polarity of each cloud should be unchanged during the passage of ISEE 3; through the cloud. We use the dominant heat flux in bidirectional electron heat fluxes to determine the cloud polarities and find that the polarity changes in at least 2 and possibly 6 of the 14 clouds, meaning that those clouds cannot fit the popular model of a single flux rope. We have also examined the large-scale fields with bidirectional electron fluxes that follow some magnetic clouds. We recently conjectured that these following fields were the trailing legs of flux rope loops. For that picture to be valid, the clouds and their trailing fields must have opposite polarities and matching magnetic chiralities. We use a simple scheme to test for magnetic chiralities of those clouds and their trailing fields and find that only 1 of 8 may have the flux rope loop geometry. C1 USAF, Res Lab, VSBS, Hanscom AFB, MA 01731 USA. Boston Univ, Ctr Space Phys, Boston, MA 02215 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Kahler, SW (reprint author), USAF, Res Lab, VSBS, 29 Randolph Rd, Hanscom AFB, MA 01731 USA. EM kahler@plh.af.mil NR 29 TC 11 Z9 11 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1999 VL 104 IS A5 BP 9911 EP 9918 DI 10.1029/1999JA900040 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 192BQ UT WOS:000080058600021 ER PT J AU Kahler, SW Crooker, NU Gosling, JT AF Kahler, SW Crooker, NU Gosling, JT TI The polarities and locations of interplanetary coronal mass ejections in large interplanetary magnetic sectors SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID EVENTS; BOUNDARIES; TOPOLOGY; CLOUDS; FIELD; ELECTRONS; SHEETS AB We have surveyed the ISEE 3 electron heat flux data to determine the polarities of the interplanetary magnetic field for the period 1978-1982. Many intervals of bidirectional electron (BDE) heat fluxes, signatures of the closed fields of interplanetary coronal mass ejections (ICMEs), were distributed among the magnetic sectors, often carrying sector boundaries. Here we examine the distribution of BDE intervals within the longest lived sectors of the ISEE 3 period to determine where ICMEs occur relative to the heliospheric current sheet (HCS). The intrasector BDE intervals, with polarities matching those of the sectors, appear to be uniformly distributed within the sectors, indicating that those ICMEs are not closely confined to the HCS. We estimate the ratio of intrasector matching polarity BDE intervals to opposite polarity BDE intervals to be about 10. The small number and short duration of opposite polarity BDE intervals suggest that injections of opposite polarity coronal mass ejections into sectors are rare. We found a number of mixed polarity BDE intervals, containing both matching and opposite polarities. These mixed polarity BDE intervals occur a factor of 5 less often than the single polarity BDE intervals alone do but are statistically more than twice as long in duration. We discuss possible origins of mixed polarity BDE intervals. C1 USAF, Res Lab, VSBS, Hanscom AFB, MA 01731 USA. Boston Univ, Ctr Space Phys, Boston, MA 02215 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Kahler, SW (reprint author), USAF, Res Lab, VSBS, 29 Randolph Rd, Hanscom AFB, MA 01731 USA. NR 28 TC 19 Z9 19 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1999 VL 104 IS A5 BP 9919 EP 9924 DI 10.1029/1999JA900084 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 192BQ UT WOS:000080058600022 ER PT J AU Toivanen, PK Pulkkinen, TI Friedel, RHW Reeves, GD Korth, A Mouikis, C Koskinen, HEJ AF Toivanen, PK Pulkkinen, TI Friedel, RHW Reeves, GD Korth, A Mouikis, C Koskinen, HEJ TI Time-dependent modeling of particles and electromagnetic fields during the substorm growth phase: Anisotropy of energetic electrons SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID PITCH ANGLE DISTRIBUTIONS; TAIL CURRENT SHEET; MAGNETIC-FIELD; SYNCHRONOUS ORBIT; PLASMA SHEET; MARCH 24; 1991 SSC; MAGNETOSPHERE; SIMULATION; DYNAMICS AB We use a bounce-averaged drift model with realistic electromagnetic fields together with magnetic field and electron data obtained by CRRES to study energetic electron distributions during the growth phase of an isolated substorm on December 12, 1990. The magnetic field model includes the actual time evolution of the geomagnetic field as measured by CRRES. The inductive electric field caused by the time evolution of the magnetic field configuration is included in the drift model to consider fully electromagnetic fields. The drift motion is computed for all pitch angles and for the entire energy range covered by the medium-energy spectrometer on CRRES. By using the Liouville theorem we are able to map electron distributions from orbit to orbit to model their time evolution in the model fields. To test the model predictions, we examine the substorm growth phase on December 12, 1990: A quiet period of about 20 hours preceded the growth phase that led to the expansion phase of a 500-nT substorm. The outer belt energetic electron distributions showed a clear development of magnetic field-aligned pitch angle anisotropy. This period was covered by two CRRES orbits, 339 and 340. During orbit 339, CRRES measured a quiet time distribution of energetic electrons. During orbit 340 the substorm onset was seen as a rapid dipolarization of the magnetic field and by a dispersionless electron injection. The quiet time fluxes were used as initial conditions for the model for fluxes during the growth phase. conclude that pitch angle dependent energization of the drifting electrons caused by the inductive electric field plays an essential role in development of the outer belt electron distributions during the substorm growth phase. C1 Finnish Meteorol Inst, FIN-00101 Helsinki, Finland. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Max Planck Inst Aeron, D-37189 Katlenburg Lindau, Germany. Univ Helsinki, Dept Phys, FIN-00014 Helsinki, Finland. RP Toivanen, PK (reprint author), Univ Colorado, Atmospher & Space Phys Lab, 1234 Innovat Dr, Boulder, CO 80309 USA. RI Friedel, Reiner/D-1410-2012; Reeves, Geoffrey/E-8101-2011; Pulkkinen, Tuija/D-8403-2012; Koskinen, Hannu/B-4971-2017 OI Friedel, Reiner/0000-0002-5228-0281; Reeves, Geoffrey/0000-0002-7985-8098; Pulkkinen, Tuija/0000-0002-6317-381X; Koskinen, Hannu/0000-0003-3839-6461 NR 48 TC 1 Z9 1 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1999 VL 104 IS A5 BP 10205 EP 10220 DI 10.1029/1998JA900138 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 192BQ UT WOS:000080058600046 ER PT J AU Hurricane, OA Fong, BH Cowley, SC Coroniti, FV Kennel, CF Pellat, R AF Hurricane, OA Fong, BH Cowley, SC Coroniti, FV Kennel, CF Pellat, R TI Substorm detonation SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID INTERPLANETARY MAGNETIC-FIELD; LOW-FREQUENCY PERTURBATIONS; NEAR-EARTH MAGNETOTAIL; SYNCHRONOUS ALTITUDE; STOCHASTIC PLASMA; INSTABILITY; MAGNETOSPHERE; STORM; SHEET; MAGNETOHYDRODYNAMICS AB The rapid, Alfvenic timescale of "onset" has been an enigma ever since magnetospheric substorms were first identified. Investigators have proposed a variety of trigger mechanisms in an effort to account for the abrupt reconfiguration observed. No one mechanism clearly stands out as the single cause of substorms. Recent analysis has demonstrated that field lines in the tail of the magnetosphere are metastable to ballooning type instabilities via a process called "nonlinear magnetohydrodynamic detonation." Furthermore, the perturbation amplitude necessary to activate the nonlinear instability is not large. Thus a variety of external and internal perturbations can trigger the same basic nonlinear instability. The evidence for detonation as a medium for the unification of substorm triggers is discussed. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08540 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. CEA, F-75752 Paris 15, France. RP Lawrence Livermore Natl Lab, POB 808,L-312, Livermore, CA 94550 USA. EM hurricane1@llnl.gov; bhl-fong@physics.ucla.edu; cow-ley@physics.ucla.edu; coroniti@physics.ucla.edu; cken-nel@ucsd.edu; pel-latr@portos.cea.fr NR 55 TC 42 Z9 43 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1999 VL 104 IS A5 BP 10221 EP 10231 DI 10.1029/1999JA900012 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 192BQ UT WOS:000080058600047 ER PT J AU Korotova, GI Sibeck, DG Moretto, T Reeves, GD AF Korotova, GI Sibeck, DG Moretto, T Reeves, GD TI Tracking transient events through geosynchronous orbit SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID FLUX-TRANSFER EVENTS; DYNAMIC PRESSURE VARIATIONS; MAGNETIC-FIELD SIGNATURES; LATITUDE BOUNDARY-LAYER; MAGNETOSPHERIC PULSATIONS; IONOSPHERIC CONVECTION; DAYSIDE MAGNETOSPHERE; IMPULSIVE PENETRATION; MAGNETOPAUSE; MOTION AB Impulsive events in high-latitude dayside ground magnetograms provide evidence for one or more modes of unsteady solar wind-magnetosphere interaction. We use geosynchronous magnetic field and energetic electron observations to demonstrate that the events correspond to abrupt global variations in both the magnetospheric magnetic field strength and the energetic electron flux and that these variations are particularly marked in the dayside magnetosphere. The multiple spacecraft observations suggest that the events move both dawnward and duskward from a point of origin on the prenoon magnetopause during periods of orthospiral, duskward, and northward interplanetary magnetic field orientation. Event properties are consistent with an interpretation in terms of widespread solar wind pressure fronts striking the bow shock and magnetopause. C1 Inst Terr Magnetism Ionosphere & Radiowave Propag, Troitsk, Moscow Region, Russia. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Danish Space Res Inst, DK-2100 Copenhagen, Denmark. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Korotova, GI (reprint author), IZMIRAN, Troitsk 142092, Moscow Region, Russia. RI Sibeck, David/D-4424-2012; Moretto, Therese/B-6846-2013; Reeves, Geoffrey/E-8101-2011 OI Moretto, Therese/0000-0002-2403-5561; Reeves, Geoffrey/0000-0002-7985-8098 NR 33 TC 15 Z9 15 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1999 VL 104 IS A5 BP 10265 EP 10273 DI 10.1029/1999JA900098 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 192BQ UT WOS:000080058600051 ER PT J AU Lee, S Choi, SUS Li, S Eastman, JA AF Lee, S Choi, SUS Li, S Eastman, JA TI Measuring thermal conductivity of fluids containing oxide nanoparticles SO JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME LA English DT Article DE conduction; enhancement; heat transfer; nanoscale; two-phase ID CONTACT RESISTANCE; COMPOSITES; PARTICLES AB Oxide nanofluids were produced and their thermal conductivities were measured by a transient hot-wire method. The experimental results show that these nanofluids, containing a small amount of nanoparticles, have substantially higher thermal conductivities than the same liquids without nanoparticles. Comparisons between experiments and the Hamilton and Crosser model show that the model can predict the thermal conductivity of nanofluids containing large agglomerated Al2O3 particles. However, the model appears to be inadequate for nanofluids containing CuO particles. This suggests that not only particle shape but size is considered to be dominant in enhancing the thermal conductivity of nanofluids. C1 Kyonggi Univ, Dept Mech Engn, Suwon, Kyonggi Do, South Korea. Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Lee, S (reprint author), Kyonggi Univ, Dept Mech Engn, Suwon, Kyonggi Do, South Korea. RI Eastman, Jeffrey/E-4380-2011; OI Eastman, Jeff/0000-0002-0847-4265 NR 38 TC 1326 Z9 1384 U1 19 U2 188 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0022-1481 J9 J HEAT TRANS-T ASME JI J. Heat Transf.-Trans. ASME PD MAY PY 1999 VL 121 IS 2 BP 280 EP 289 DI 10.1115/1.2825978 PG 10 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 207TN UT WOS:000080952000004 ER PT J AU Hon, YC Cheung, KF Mao, XZ Kansa, EJ AF Hon, YC Cheung, KF Mao, XZ Kansa, EJ TI Multiquadric solution for shallow water equations SO JOURNAL OF HYDRAULIC ENGINEERING-ASCE LA English DT Article ID PARTIAL-DIFFERENTIAL EQUATIONS; COMPUTATIONAL FLUID-DYNAMICS; POSITIVE DEFINITE FUNCTIONS; DATA APPROXIMATION SCHEME; FINITE-ELEMENT MODEL; SCATTERED DATA; INTERPOLATION; TIDES AB A computational algorithm based on the multiquadric, which is a continuously differentiable radial basis function, is devised to solve the shallow water equations. The numerical solutions are evaluated at scattered collocation points and the spatial partial derivatives are formed directly from partial derivatives of the radial basis function, not by any difference scheme. The method does not require the generation of a grid as in the finite-element method and allows easy editing and refinement of the numerical model. To increase confidence in the multiquadric solution, a sensitivity and convergence analysis is performed using numerical models of a rectangular channel. Applications of the algorithm are made to compute the sea surface elevations and currents in Tolo Harbour, Hong Kong, during a typhoon attack. The numerical solution is shown to be robust and stable. The computed results are compared with measured data and good agreement is indicated. C1 City Univ Hong Kong, Dept Math, Hong Kong, Hong Kong. Univ Hawaii Manoa, Dept Occupat Engn, Honolulu, HI 96822 USA. Zhejiang Prov Inst Estuarine & Coast Engn Res, Hangzhou, Zhejiang, Peoples R China. Univ Calif Lawrence Livermore Natl Lab, Dept Earth & Environm Sci, Livermore, CA 94551 USA. RP Hon, YC (reprint author), City Univ Hong Kong, Dept Math, Hong Kong, Hong Kong. OI Hon, Benny/0000-0001-5224-6238 NR 34 TC 140 Z9 141 U1 0 U2 2 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 USA SN 0733-9429 J9 J HYDRAUL ENG-ASCE JI J. Hydraul. Eng.-ASCE PD MAY PY 1999 VL 125 IS 5 BP 524 EP 533 DI 10.1061/(ASCE)0733-9429(1999)125:5(524) PG 10 WC Engineering, Civil; Engineering, Mechanical; Water Resources SC Engineering; Water Resources GA 189UB UT WOS:000079923600010 ER PT J AU Martinez, RA Silks, LA Unkefer, CJ AF Martinez, RA Silks, LA Unkefer, CJ TI Synthesis of tert-butyl-[1-C-13]glycolic acid SO JOURNAL OF LABELLED COMPOUNDS & RADIOPHARMACEUTICALS LA English DT Article DE tert-butyl-[1-C-13]glycolic acid; alkoxy-methyl anion; tert-butylmethyl ether; [C-13]carbon dioxide ID DEOXYRIBOSE-5-PHOSPHATE ALDOLASE; CATALYST AB A one step synthesis of tert-butyl-[1-C-13]glycolic acid was accomplished by a modification of the Corey and Eckrich procedure, tert-Butyl methyl ether was metallated by treatment with sec-butyl lithium and potassium tert-butoxide at -78 degrees C. Carbonation with (CO2)-C-13 yielded tert-butyl-[1-C-13]glycolic acid. C1 Univ Calif Los Alamos Natl Lab, Natl Stable Isotope Resource, Los Alamos, NM 87545 USA. RP Martinez, RA (reprint author), Univ Calif Los Alamos Natl Lab, Natl Stable Isotope Resource, CST-4,MS G758, Los Alamos, NM 87545 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0362-4803 J9 J LABELLED COMPD RAD JI J. Label. Compd. Radiopharm. PD MAY PY 1999 VL 42 IS 5 BP 505 EP 508 PG 4 WC Biochemical Research Methods; Chemistry, Medicinal; Chemistry, Analytical; Pharmacology & Pharmacy SC Biochemistry & Molecular Biology; Pharmacology & Pharmacy; Chemistry GA 192QC UT WOS:000080089500011 ER PT J AU Bielicki, JK Forte, TM AF Bielicki, JK Forte, TM TI Evidence that lipid hydroperoxides inhibit plasma lecithin : cholesterol acyltransferase activity SO JOURNAL OF LIPID RESEARCH LA English DT Article DE phospholipid hydroperoxides; lecithin : cholesterol acyltransferase; high density lipoproteins; minimally oxidized LDL; atherogenesis ID LOW-DENSITY-LIPOPROTEIN; OXIDATIVE MODIFICATION; OXIDIZED LDL; A-I; HDL; APOLIPOPROTEINS; ATHEROGENESIS; PARAOXONASE; RECRUITMENT; MACROPHAGES AB The oxidation of low density lipoproteins (LDL) has been implicated in the development of atherosclerosis, Recently, we found that polar lipids isolated from minimally oxidized LDL produced a dramatic inhibition of lecithin: cholesterol acyltransferase (LCAT) activity, suggesting that HDL-cholesterol transport may be impaired during early atherogenesis, In this study, we have identified molecular species of oxidized lipids that are potent inhibitors of LCAT activity, Treatment of LDL with soybean lipoxygenase generated small quantities of lipid hydroperoxides (20 +/- 4 nmol/mg LDL protein, n = 3); but when lipoxygenase-treated LDL (1 mg protein/ml) was recombined with the d > 1.063 g/ml fraction of human plasma, LCAT activity was rapidly inhibited (25 +/- 1 and 65 +/- 16% reductions by I and 3 h, respectively). As phospholipid hydroperoxides (PL-OOH) are the principal oxidation products associated with lipoxygenase-treated LDL, we directly tested whether PL-OOH inhibited plasma LCAT activity. Detailed dose-response curves revealed that as little as 0.2 and 1.0 mole % enrichment of plasma with PL-OOH produced 20 and 50% reductions in LCAT activity by 2 h, respectively To gain insight into the mechanism of LCAT impairment, the enzyme's free cysteines (Cys31 and Cys184) and active site residues were "capped" with the reversible sulfhydryl compound, DTNB, during exposure to either minimally oxidized LDL or PL-OOH. Reversal of the DTNB "cap" after such exposures revealed that the enzyme was completely protected from both sources of peroxidized pbospholipids. We, therefore, conclude that PL-OOH inhibited plasma LCAT activity by modifying the enzyme's free cysteine and/or catalytic residues. These studies are the first to suggest that PL-OOH may accelerate the atherogenic process by impairing LCAT activity. C1 Univ Calif Berkeley, Div Life Sci, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Bielicki, JK (reprint author), Univ Calif Berkeley, Div Life Sci, Lawrence Berkeley Natl Lab, 1 Cyclotron Rd, Berkeley, CA 94720 USA. FU NHLBI NIH HHS [HL07279, HL18754] NR 39 TC 54 Z9 57 U1 0 U2 0 PU LIPID RESEARCH INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0022-2275 J9 J LIPID RES JI J. Lipid Res. PD MAY PY 1999 VL 40 IS 5 BP 948 EP 954 PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 193XT UT WOS:000080163600018 PM 10224164 ER PT J AU Brunner, E Haake, M Kaiser, L Pines, A Reimer, JA AF Brunner, E Haake, M Kaiser, L Pines, A Reimer, JA TI Gas flow MRI using circulating laser-polarized Xe-129 SO JOURNAL OF MAGNETIC RESONANCE LA English DT Article DE laser-polarized Xe-129; MRI; gas flow imaging; continuous flow ID HYPERPOLARIZED HE-3; NMR; DIFFUSION; GRADIENT; XENON AB We describe an experimental approach that combines multidimensional NMR experiments with a steadily renewed source of laser-polarized Xe-129. Using a continuous flow system to circulate the gas mixture, gas phase NMR signals of laser-polarized Xe-129 can be observed with an enhancement of three to four orders of magnitude compared to the equilibrium Xe-129 NMR signal. Due to the fact that the gas flow recovers the nonequilibrium Xe-129 nuclear spin polarization in 0.2 to 4 s, signal accumulation on the time scale of seconds is feasible, allowing previously inaccessible phase cycling and signal manipulation. Several possible applications of MRI of laser-polarized Xe-129 under continuous flow conditions are presented here. The spin density images of capillary tubes demonstrate the feasibility of imaging under continuous how. Dynamic displacement profiles, measured by a pulsed gradient spin echo experiment, show entry flow properties of the gas passing through a constriction under laminar flow conditions. Further, dynamic displacement profiles of Xe-129, flowing through polyurethane foams with different densities and pore sizes, are presented. (C) 1999 Academic Press. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. RP Kaiser, L (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. NR 15 TC 43 Z9 43 U1 2 U2 6 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1090-7807 J9 J MAGN RESON JI J. Magn. Reson. PD MAY PY 1999 VL 138 IS 1 BP 155 EP 159 DI 10.1006/jmre.1998.1675 PG 5 WC Biochemical Research Methods; Physics, Atomic, Molecular & Chemical; Spectroscopy SC Biochemistry & Molecular Biology; Physics; Spectroscopy GA 196HX UT WOS:000080303900021 PM 10329238 ER PT J AU Lewis, LH Panchanathan, V AF Lewis, LH Panchanathan, V TI The influence of chromium additions on the magnetic properties of Nd-2(Fe,Co)(14)B-based nanocomposites SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article; Proceedings Paper CT 7th European Magnetic Materials and Applications Conference (EMMA 98) CY SEP 09-12, 1998 CL ZARAGOZA, SPAIN SP Comis Interministerial Ciencia & Tecnoloiga, Consejo Super Investigaciones Cientificas, Diputac Gen Aragon, OPEL-Espana, Univ Zaragoza DE nanocomposite; metastable phases; intermetallic compounds; magnetic properties; rapid solidification; exchange spring AB The phase transformation behavior of melt-spun nanocomposite alloys of composition Nd-2[Co-0.06 (Fe1-xCrx)(0.94)](23.2)B-1.48 (0 less than or equal to X < 0.09) as a function of chromium content ultimately controls the final phase constitution, character and chemistry of the alloys, which in turn control their room-temperature hysteretic magnetic properties. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Dept Appl Sci, Div Mat Sci, Upton, NY 11973 USA. Magnequench Int Inc, Anderson, IN 46013 USA. RP Lewis, LH (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Div Mat Sci, Bldg 480, Upton, NY 11973 USA. EM lhlewis@bnl.gov NR 3 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD MAY PY 1999 VL 196 BP 299 EP 301 DI 10.1016/S0304-8853(98)00720-3 PG 3 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 195VB UT WOS:000080271900114 ER PT J AU Bartolome, F Tonnerre, JM Seve, L Raoux, D Chaboy, J Garcia, LM Krisch, M Kao, CC AF Bartolome, F Tonnerre, JM Seve, L Raoux, D Chaboy, J Garcia, LM Krisch, M Kao, CC TI Resonant inelastic X-ray scattering study of rare-earth electronic excitation on R2Fe14B SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article; Proceedings Paper CT 7th European Magnetic Materials and Applications Conference (EMMA 98) CY SEP 09-12, 1998 CL ZARAGOZA, SPAIN SP Comis Interministerial Ciencia & Tecnoloiga, Consejo Super Investigaciones Cientificas, Diputac Gen Aragon, OPEL-Espana, Univ Zaragoza DE X-ray spectroscopy; RIXS; XMCD ID CIRCULAR-DICHROISM AB Resonant inelastic X-ray scattering spectra are recorded at the L-3 absorption edge of rare-earth ions in R2Fe14B. In all cases, weak resonances are observed at energies below the dipolar whiteline, ascribed to 2p --> 4f quadrupolar excitations. Their energy position is in excellent agreement with the pre-edge features in the XMCD spectra of the same samples. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Zaragoza, Fac Ciencias, CSIC, Inst Ciencia Mat Aragon, E-50009 Zaragoza, Spain. CNRS, Cristallog Lab, F-38042 Grenoble, France. European Synchrotron Radiat Facil, F-38043 Grenoble, France. Brookhaven Natl Lab, NSLS, Upton, NY 11973 USA. RP Bartolome, F (reprint author), Univ Zaragoza, Fac Ciencias, CSIC, Inst Ciencia Mat Aragon, E-50009 Zaragoza, Spain. EM bartolome@posta.unizar.es RI Bartolome, Fernando/K-1700-2014 OI Bartolome, Fernando/0000-0002-0047-1772 NR 9 TC 0 Z9 0 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD MAY PY 1999 VL 196 BP 779 EP 781 DI 10.1016/S0304-8853(98)00959-7 PG 3 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 195VB UT WOS:000080271900296 ER PT J AU You, CY Bader, SD AF You, CY Bader, SD TI Prediction of switching rotation of the magnetization direction with applied voltage in a controllable interlayer exchange coupled system SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article DE controllable interlayer exchange coupling; tunneling; quantum well; magnetization direction; bias voltage AB We propose a ferromagnetic/spacer/insulator/ferromagnetic system whose magnetization direction can be controlled by an applied bias voltage. An analytic expression for controllable exchange coupling in this system is shown within a simple free-electron-like, one-dimensional approximation. According to the approach, the magnetic configurations of two magnetic layers oscillate from antiferromagnetic to ferromagnetic with applied bias voltage. This implies that we can switch/rotate the magnetization direction without an external magnetic field. Possible applications of such a system are discussed. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP You, CY (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI You, Chun-Yeol/B-1734-2010; Bader, Samuel/A-2995-2013 OI You, Chun-Yeol/0000-0001-9549-8611; NR 10 TC 23 Z9 23 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD MAY PY 1999 VL 195 IS 2 BP 488 EP 500 DI 10.1016/S0304-8853(99)00233-4 PG 13 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 196HH UT WOS:000080302600030 ER PT J AU Lankalapalli, KN Tu, JF Leong, KH Gartner, M AF Lankalapalli, KN Tu, JF Leong, KH Gartner, M TI Laser weld penetration estimation using temperature measurements SO JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article ID KEYHOLE; MODEL AB Penetration depth is an important factor critical to the quality of a laser weld. This paper presents a 3D heat conduction model with a moving line source to correlate the temperature measured on the bottom surface of the workpiece to the weld penetration, weld bend width and welding speed. Temperatures on the bottom surface of the workpiece are measured using infrared thermocouples located behind the laser beam. The averaging effect due to the temperature measurement spot size is analyzed. This paper provides a model-based approach for laser weld penetration monitoring instead of a pure empirical correlation between a measured signal (e.g., acoustic, infrared) and the penetration depth. Experiments were conducted to compare the depth estimation based on the model to bead-on-plate welds on low carbon steel plates of varying thickness at different laser power levels and speeds. It is shown that the temperature on the bottom surface is a consistent indicator of penetration depth and that the correlation is also sensitive to the sensor location as well as other process conditions such as weld shape, width, and the plate thickness. The proposed model is computationally efficient and is suitable for on-line process monitoring application. C1 FANUC Robot N Amer Inc, Rochester Hills, MI 48307 USA. Purdue Univ, Sch Ind Engn, W Lafayette, IN 47907 USA. Argonne Natl Lab, Laser Applicat Lab, Technol Dev Div, Argonne, IL 60439 USA. Ford Motor Co, Livonia, MI 48150 USA. RP Lankalapalli, KN (reprint author), FANUC Robot N Amer Inc, Rochester Hills, MI 48307 USA. NR 33 TC 7 Z9 8 U1 1 U2 8 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1087-1357 J9 J MANUF SCI E-T ASME JI J. Manuf. Sci. Eng.-Trans. ASME PD MAY PY 1999 VL 121 IS 2 BP 179 EP 188 DI 10.1115/1.2831202 PG 10 WC Engineering, Manufacturing; Engineering, Mechanical SC Engineering GA 201AD UT WOS:000080571700004 ER PT J AU Preisler, J Yeung, ES AF Preisler, J Yeung, ES TI Derivatization of amino acids for enhanced ion yield in laser desorption/post-ionization mass spectrometry SO JOURNAL OF MASS SPECTROMETRY LA English DT Letter ID RESONANT 2-PHOTON IONIZATION; MULTIPHOTON IONIZATION; PHOTON IONIZATION; ORGANIC-MOLECULES; AQUEOUS-SOLUTION; 193 NM; BIOMOLECULES; PHOTOIONIZATION; SPECTROSCOPY; PHOTOLYSIS C1 US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP Yeung, ES (reprint author), US DOE, Ames Lab, Ames, IA 50011 USA. RI Preisler, Jan/B-2005-2009 OI Preisler, Jan/0000-0002-9819-1284 NR 32 TC 0 Z9 0 U1 0 U2 1 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 1076-5174 J9 J MASS SPECTROM JI J. Mass Spectrom. PD MAY PY 1999 VL 34 IS 5 BP 563 EP 565 DI 10.1002/(SICI)1096-9888(199905)34:5<563::AID-JMS796>3.0.CO;2-K PG 3 WC Biophysics; Chemistry, Organic; Spectroscopy SC Biophysics; Chemistry; Spectroscopy GA 198FU UT WOS:000080413100013 ER PT J AU Narula, CK Allard, LF Graham, GW AF Narula, CK Allard, LF Graham, GW TI Sol-gel processed fluorite-structured PrOy-ZrO2 mixed oxides deposited on alumina SO JOURNAL OF MATERIALS CHEMISTRY LA English DT Article ID OXYGEN AVAILABILITY AB Preparation of PrOy (Pr6O11) or single-phase fluorite-structured PrOy-ZrO2 mixed oxide, supported on high-surface-area gamma-alumina, was achieved for the first time by impregnation of gamma-alumina powder with Pr((OC3H7)-C-1)(3) or a mixture of Pr((OC3H7)-C-1)(3)and Zr((OC3H7)-C-1)(4)(C3H7OH)-C-.1 and calcination 600 degrees C. Subsequent calculation at 900 degrees C caused partial transformation of Pr6O11 to PrAlO3 but only improved the crystallinity of the mixed oxide. Further calcination at 1200 degrees C led to complete transformation df Pr6O11 but only partial disproportionation of PrOy-ZrO2 to PrAlO3 and ZrO2, transformation of gamma- to alpha-alumina was also inhibited in the case of the mixed oxide. In contrast, there was no evidence of any crystalline phase containing praseodymium upon calcination of gamma-alumina powder impregnated with a mixture of praseodymium nitrate and zirconium chloride in a 1 :0 or 1 : 1 molar ratio. These results show that praseodymium oxide can be supported on alumina and stabilized against reaction with the alumina by the incorporation of zirconium in the form of the mixed oxide, PrOy,ZrO2, provided it is deposited using alkoxide precursors. This stabilization should allow praseodymia to undergo redox processes and thus provide oxygen storage capacity when supported on alumina in a catalyst washcoat. C1 Ford Motor Co, Dept Chem, Dearborn, MI 48121 USA. Oak Ridge Natl Lab, HTML, Oak Ridge, TN 37831 USA. RP Narula, CK (reprint author), Ford Motor Co, Dept Chem, MD3083,SRL,POB 2053, Dearborn, MI 48121 USA. NR 13 TC 6 Z9 6 U1 1 U2 1 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD,, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND SN 0959-9428 J9 J MATER CHEM JI J. Mater. Chem. PD MAY PY 1999 VL 9 IS 5 BP 1155 EP 1159 DI 10.1039/a809200a PG 5 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 198FK UT WOS:000080411900019 ER PT J AU Zeuch, DH Montgomery, ST Holcomb, DJ AF Zeuch, DH Montgomery, ST Holcomb, DJ TI The effects of nonhydrostatic compression and applied electric field on the electromechanical behavior of poled lead zirconate titanate 95/5-2Nb ceramic during the ferroelectric to antiferroelectric polymorphic transformation SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID SOLID-SOLUTION SYSTEM; THERMODYNAMIC THEORY; PHASE-TRANSFORMATION; STRESS AB We conducted hydrostatic compression and constant-stress-difference experiments, with and without an applied electric field, on poled, niobium-doped lead zirconate titanate ceramic. The objective was to quantify the effects of nonhydrostatic stress and electric field bias on electromechanical behavior of the ceramic during the ferroelectric, rhombohedral -->, antiferroelectric, orthorhombic phase transformation. Increasing stress difference (shear stress) decreases the mean stress at which the transformation occurs. Increasing shear stress also retards the rate of transformation, causing reductions in both the rate of charge release and peak voltage attained during depoling. Application of the electric field bias slightly increases the transformation pressure for poled ceramic. Previously, we showed that under nonhydrostatic stress, the transformation took place in unpoled ceramic when the maximum compressive stress equalled the hydrostatic pressure at which the transformation would otherwise occur. This simple stress criterion does not apply to poled ceramic. However, poled material has a preferred crystallographic orientation and mechanical anisotropy, whereas unpoled ceramic is isotropic. We present a qualitative model for the transformation under nonhydrostatic stress-related to that anisotropy, which resolves these seemingly disparate observations. C1 Sandia Natl Labs, Geomech Dept 6117, Albuquerque, NM 87185 USA. Sandia Natl Labs, Integrated Prod Dev Dept 1567, Albuquerque, NM 87185 USA. RP Zeuch, DH (reprint author), Sandia Natl Labs, Geomech Dept 6117, POB 5800, Albuquerque, NM 87185 USA. NR 27 TC 20 Z9 22 U1 1 U2 4 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD MAY PY 1999 VL 14 IS 5 BP 1814 EP 1827 DI 10.1557/JMR.1999.0245 PG 14 WC Materials Science, Multidisciplinary SC Materials Science GA 235PD UT WOS:000082550500021 ER PT J AU Indacochea, JE Smith, JL Litko, KR Karell, EJ AF Indacochea, JE Smith, JL Litko, KR Karell, EJ TI Corrosion performance of ferrous and refractory metals in molten salts under reducing conditions SO JOURNAL OF MATERIALS RESEARCH LA English DT Article AB A lithium reduction technique to condition spent fuel for disposal has been developed at the Argonne National Laboratory. There is a need to ensure adequate vessel longevity through corrosion testing and, if necessary, materials development. Several ferrous alloys and tantalum specimens were submitted to a corrosion test at 725 degrees C for thirty days in an argon atmosphere, using a lithium-chloride salt saturated with lithium metal and containing small amounts of lithium oxide and lithium nitride. The samples did not show dimensional or weight change, nor could corrosion attack be detected metallographically. The lithium-saturated salt system did not show any behavior similar to that of liquid lithium corrosion. From testing in other gas compositions, it appears that the presence of oxygen in the system is necessary to produce severe corrosion. C1 Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. RP Indacochea, JE (reprint author), Argonne Natl Lab, Div Chem Technol, Bldg 205,9700 S Cass Ave, Argonne, IL 60439 USA. NR 29 TC 19 Z9 27 U1 0 U2 3 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD MAY PY 1999 VL 14 IS 5 BP 1990 EP 1995 DI 10.1557/JMR.1999.0268 PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA 235PD UT WOS:000082550500044 ER PT J AU He, XM Lee, DH Walter, KC Li, DQ Nastasi, M AF He, XM Lee, DH Walter, KC Li, DQ Nastasi, M TI Structure and optical properties of diamondlike carbon synthesized by plasma immersion ion processing SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID ELECTRON-CYCLOTRON-RESONANCE; CHEMICAL-VAPOR-DEPOSITION; AMORPHOUS HYDROGENATED CARBON; FILM GROWTH; BIAS AB Hard and transparent diamondlike carbon (DLC) films have been prepared on room-temperature substrates by using a C2H2-Ar plasma immersion ion processing (PIIP) method. The optical properties of the DLC films with different thicknesses deposited on PMMA (polymethyl methacrylate), silicon wafers, and glass plates were systematically examined. It was found that careful control of substrate bias voltage was needed for favorable growth of DLC films with low atomic hydrogen content, high hardness and wear resistance, and excellent optical properties. The resultant DLC films exhibited a low friction coefficient, high optical gap energy, and very high optical transmittance both in infrared and visible light ranges. The study confirmed that C2H2-Ar PIIP with low negative bias voltages and suitable C2H2/Ar gas ratios can produce optically transparent and hard DLC films on optical materials. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Dept Chem Sci & Technol, Los Alamos, NM 87545 USA. RP He, XM (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, POB 1663, Los Alamos, NM 87545 USA. NR 27 TC 8 Z9 8 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD MAY PY 1999 VL 14 IS 5 BP 2080 EP 2087 DI 10.1557/JMR.1999.0280 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA 235PD UT WOS:000082550500056 ER PT J AU Shen, TD He, Y Schwarz, RB AF Shen, TD He, Y Schwarz, RB TI Bulk amorphous Pd-Ni-Fe-P alloys: Preparation and characterization SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID SOFT-MAGNETIC PROPERTIES; METALLIC-GLASS; LIQUID; SYSTEM; STABILITY; STRENGTH; STATE AB Bulk amorphous alloys of PdxNiyFe80-x-yP20 (25 less than or equal to x less than or equal to 60, 20 less than or equal to y less than or equal to 55, x + y greater than or equal to 60) were prepared by a flux-melting and water-quenching method. Seven-mm diameter glassy rods of Pd40Ni40-xFexP20 (0 less than or equal to x less than or equal to 20) were studied in greater detail. For these alloys, the difference between the crystallization and glass transition temperatures ranges from 102 K for x = 0 to 53 K for x = 20. In this composition range, the reduced glass transition temperature, T-rg, ranges from 0.66 to 0.57. The change in density upon crystallization ranges from 0.24 +/- 0.04% for x = 0 to 1.33 +/- 0.24% for x = 10. The partial molar volume of Fe in amorphous Pd40Ni40-xFexP20 alloys is significantly larger than the molar volume of (metastable) fee Fe. This, as well as a comparison with the molar volumes of crystalline compounds, suggests chemically selective Fe-Pd bonding in these glasses. C1 Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Los Alamos Natl Lab, Div Mat Sci & Technol, MS K765, Los Alamos, NM 87545 USA. NR 35 TC 43 Z9 45 U1 1 U2 5 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0884-2914 EI 2044-5326 J9 J MATER RES JI J. Mater. Res. PD MAY PY 1999 VL 14 IS 5 BP 2107 EP 2115 DI 10.1557/JMR.1999.0285 PG 9 WC Materials Science, Multidisciplinary SC Materials Science GA 235PD UT WOS:000082550500061 ER PT J AU Brosha, EL Davey, J Garzon, FH Gottesfeld, S AF Brosha, EL Davey, J Garzon, FH Gottesfeld, S TI Irreversible hydrogenation of solid C-60 with and without catalytic metals SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID BUCKMINSTERFULLERENE C-60; HARD CARBONS; VEHICLES AB The dehydrogenation of C-60. H-18.7 was studied using thermogravimetric and powder x-ray diffraction analysis. C-60. H-18.7 was found to be stable up to 430 degrees C in Ar at which point the release of hydrogen initiated the collapse of a fraction of fullerene molecules. X-ray diffraction analysis performed on C-60. H-18.7 samples dehydrogenated at 454, 475, and 600 degrees C displayed an increasing volume fraction of amorphous material. The decomposition product comprises randomly oriented, single-layer graphite sheets. Evolved gas analysis using gas chromatograph (GC) mass spectroscopy confirmed the presence of both H-2 and methane upon dehydrogenation. Attempts to improve reversibility or reduce hydrogenation/dehydrogenation temperatures by addition of Ru and Pt catalysts were unsuccessful. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Brosha, EL (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 24 TC 16 Z9 16 U1 0 U2 2 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD MAY PY 1999 VL 14 IS 5 BP 2138 EP 2146 DI 10.1557/JMR.1999.0289 PG 9 WC Materials Science, Multidisciplinary SC Materials Science GA 235PD UT WOS:000082550500065 ER PT J AU Nastasi, M Kodali, P Walter, KC Embury, JD Raj, R Nakamura, Y AF Nastasi, M Kodali, P Walter, KC Embury, JD Raj, R Nakamura, Y TI Fracture toughness of diamondlike carbon coatings SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID INDENTATION FRACTURE; SILICON; STRESSES; FILMS AB The fracture behavior of diamondlike carbon (DLC) coatings on Si substrates has been examined using microindentation. The presence of DLC coatings reduces the radial crack length to less than one-half the crack length observed in uncoated Si at the same indenter load. A total work of fracture analysis of the radial cracks formed in the DLC-coating/Si-substrate system gives 10.1 MPa m(1/2) as the average fracture toughness for DLC alone. A bond-breaking calculation for DLC suggests that the elastic limit fracture toughness should be 1.5 MPa (m)(1/2). The higher value obtained from experiment and total work analysis suggests that plastic work and/or a tortuous path crack evolution occurred during DLC fracture process. C1 Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. Univ Colorado, Dept Mech Engn, Boulder, CO 80309 USA. Kagoshima Univ, Dept Engn Mech, Kagoshima 8900065, Japan. RP Nastasi, M (reprint author), Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. NR 31 TC 28 Z9 28 U1 0 U2 7 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0884-2914 EI 2044-5326 J9 J MATER RES JI J. Mater. Res. PD MAY PY 1999 VL 14 IS 5 BP 2173 EP 2180 DI 10.1557/JMR.1999.0293 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA 235PD UT WOS:000082550500069 ER PT J AU Wei, B Komvopoulos, K Brown, IG AF Wei, B Komvopoulos, K Brown, IG TI Microstructure modification of amorphous carbon films by ion-implantation techniques SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID A-C-H; HYDROGENATED DIAMONDLIKE CARBON; THIN-FILMS; DEPOSITION PARAMETERS; PLASMA DECOMPOSITION; RAMAN-SPECTROSCOPY; VACUUM; BOMBARDMENT; SCATTERING; COATINGS AB Microstructure modification of amorphous carbon films containing about 30 at.% hydrogen (a-CHx) and nonhydrogenated amorphous carbon (a-C) films was accomplished with a vacuum are metal plasma implanter and a cathodic are plasma system, respectively. The films were implanted with Si, Ti, Hf, W, and Al of ion doses approximately equal to 1 and 3 X 10(16) ions/cm(2) and mean ion kinetic energies in the range of 3-70 keV, depending on the implantation method. Simulation results demonstrated a profound effect of the size of implant species, ion dose, mean ion kinetic energy, and implantation processes on the implant spatial distributions. Statistical roughness results showed a negligible effect of ion implantation on the film surface topography. Elastic recoil spectroscopy revealed a decrease in the hydrogen content of the a-CHx films due to the ion bombardment. A monotonic decrease in the Raman scattering intensities and a downward shift of the carbon peak position occurred with increasing ion dose for both types of films and implantation techniques. Nanoindentation experiments demonstrated an effect of ion implantation on the apparent film hardness, depending on the flux and kinetic energy of implanted species. Changes in the hardness characteristics of the implanted films are interpreted in terms of the chemical reactivity of implant elements and microstructure modifications caused by irradiation damage, dehydrogenation, and higher contents of tetrahedral (sp(3)) carbon hybridization due to carbide bond formation. C1 Univ Calif Berkeley, Dept Mech Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Wei, B (reprint author), Univ Calif Berkeley, Dept Mech Engn, Berkeley, CA 94720 USA. NR 37 TC 3 Z9 3 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD MAY PY 1999 VL 14 IS 5 BP 2181 EP 2190 DI 10.1557/JMR.1999.0294 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA 235PD UT WOS:000082550500070 ER PT J AU Sugama, T Milian-Jimenez, S AF Sugama, T Milian-Jimenez, S TI Dextrine-modified chitosan marine polymer coatings SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID STARCH AB In trying to modify partially acetylated chitosan (CS) marine polymers ground from crab or shrimp shells for use as environmentally benign water-base coatings for aluminum (Al) substrates, CS was dissolved in a solution of HCL acid, and then mixed with corn starch-derived dextrine (DEX) containing Ce nitrate as oxidizing agent in aqueous medium. This blend of polysaccharides was deposited on Al surfaces by a simple dip-withdrawing method, and then heated at 200 degrees C to transform the liquid layer into a solid film. The solution --> solid phase transition provided the changes in the molecular conformation of CS and DEX; the former was transformed into deacetylated poly(D-glucosamine) and the latter referred to the formation of Ce-complexed carboxylate fragments. Furthermore, the chemical reactions between the NH2 groups in deacetylated CS and the carboxylate fragments led to the creation of amide linkages that served in grafting DEX fragments onto the CS. Such fragment-grafted CS polymer coating films deduced from the proper proportions of CS to DEX offered great film-forming performance, low susceptibility to moisture, and low ionic conductivity, conferring a salt-spray resistance of 720 hours. (C) 1999 Kluwer Academic Publishers. C1 Brookhaven Natl Lab, Dept Appl Sci, Energy Efficiency & Conservat Div, Upton, NY 11973 USA. RP Sugama, T (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Energy Efficiency & Conservat Div, Upton, NY 11973 USA. NR 18 TC 6 Z9 6 U1 1 U2 7 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD MAY 1 PY 1999 VL 34 IS 9 BP 2003 EP 2014 DI 10.1023/A:1004530920222 PG 12 WC Materials Science, Multidisciplinary SC Materials Science GA 197VX UT WOS:000080387600004 ER PT J AU Bruck, HA Rabin, BH AF Bruck, HA Rabin, BH TI Evaluating microstructural and damage effects in rule-of-mixtures predictions of the mechanical properties of Ni-Al2O3 composites SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID FINITE-ELEMENT ANALYSIS; THERMAL RESIDUAL-STRESSES; CERAMIC-METAL INTERFACES; MATRIX COMPOSITE; STRAIN BEHAVIOR; PARTICLES; GRADIENTS; ALLOYS AB 0Ni-Al2O3 composites containing 0 to 100 vol % Ni were fabricated using powder processing techniques. By varying the metal : ceramic particle size ratio, either particle-reinforced or interpenetrating-phase microstructures were obtained. The mechanical properties of the composites were characterized and compared with rule-of-mixtures (ROM) predictions. For certain particle-reinforced composites, the elastic moduli measured ultrasonically did not obey the ROM. This result was attributed to the presence of damage that could be accounted for using existing models. In four-point bending, most composites exhibited linear elastic behavior, however significant inelastic deformation was observed for composites containing 60 and 80 vol % Ni. The inelastic deformation was reasonably well described using ROM models, except when substantial damage was present. Damaged materials were modeled as two phase composites containing one damage-free phase and one completely damaged phase that was assumed to behave like a porous material. The failure strains of composites with continuous ceramic phases were explained using a semi-empirical model that included bath damage and residual stress effects. Fracture stresses were calculated from predicted fracture strains using a new ROM deformation model. The model was modified to include constraint effects in order to accurately describe the deformation behavior of the ductile continuous-ceramic composites. (C) 1999 Kluwer Academic Publishers. C1 Idaho Natl Engn Labs, Idaho Falls, ID 83415 USA. RP Bruck, HA (reprint author), Idaho Natl Engn Labs, POB 1625, Idaho Falls, ID 83415 USA. NR 31 TC 30 Z9 30 U1 1 U2 12 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD MAY 1 PY 1999 VL 34 IS 9 BP 2241 EP 2251 DI 10.1023/A:1004509220648 PG 11 WC Materials Science, Multidisciplinary SC Materials Science GA 197VX UT WOS:000080387600032 ER PT J AU Lee, SR Millunchick, JM Twesten, RD Follstaedt, DM Reno, JL Ahrenkiel, SP Norman, AG AF Lee, SR Millunchick, JM Twesten, RD Follstaedt, DM Reno, JL Ahrenkiel, SP Norman, AG TI Reciprocal-space analysis of compositional modulation in short-period superlattices using position-sensitive x-ray detection SO JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS LA English DT Article ID LATERAL COMPOSITION MODULATION; MOLECULAR-BEAM EPITAXY; LAYER ORDERING PROCESS; QUANTUM-WELLS; ALLOYS; GAXIN1-XP; GROWTH; LASERS AB Epitaxial growth of AlAs-InAs short-period superlattices on (0 0 1) InP can lead to heterostructures exhibiting strong, quasi-periodic, lateral modulation of the alloy composition; transverse satellites arise in reciprocal space as a signature of the compositional modulation. Using an x-ray diffractometer equipped with a position-sensitive x-ray detector, we demonstrate reciprocal-space mapping of these satellites as an efficient, non-destructive means for detecting and characterizing the occurrence of compositional modulation. Systematic variations in the compositional modulation due to the structural design and the growth conditions of the short-period superlattice are characterized by routine mapping of the lateral satellites. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. EM srlee@sandia.gov RI Norman, Andrew/F-1859-2010 OI Norman, Andrew/0000-0001-6368-521X NR 22 TC 15 Z9 15 U1 0 U2 8 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0957-4522 EI 1573-482X J9 J MATER SCI-MATER EL JI J. Mater. Sci.-Mater. Electron. PD MAY PY 1999 VL 10 IS 3 BP 191 EP 197 DI 10.1023/A:1008991827724 PG 7 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Engineering; Materials Science; Physics GA 204ER UT WOS:000080751500004 ER PT J AU Bender, CM Boettcher, S Meisinger, PN AF Bender, CM Boettcher, S Meisinger, PN TI PT-symmetric quantum mechanics SO JOURNAL OF MATHEMATICAL PHYSICS LA English DT Article ID FIELD THEORY; LOCALIZATION AB This paper proposes to broaden the canonical formulation of quantum mechanics. Ordinarily, one imposes the condition H dagger = H on the Hamiltonian, where dagger represents the mathematical operation of complex conjugation and matrix transposition. This conventional Hermiticity condition is sufficient to ensure that the Hamiltonian H has a real spectrum. However, replacing this mathematical condition by the weaker and more physical requirement H double dagger = H, where double dagger represents combined parity reflection and time reversal PT, one obtains new classes of complex Hamiltonians whose spectra are still real and positive. This generalization of Hermiticity is investigated using a complex deformation H = p(2) + x(2)(ix)(epsilon) of the harmonic oscillator Hamiltonian, where e is a real parameter. The system exhibits two phases: When epsilon greater than or equal to 0, the energy spectrum of H is real and positive as a consequence of PT symmetry. However, when -1 < epsilon < 0, the spectrum contains an infinite number of complex eigenvalues and a finite number of real, positive eigenvalues because PT symmetry is spontaneously broken. The phase transition that occurs at epsilon = 0 manifests itself in both the quantum-mechanical system and the underlying classical system. Similar qualitative features are exhibited by complex deformations of other standard real Hamiltonians H = p(2) + x(2)(ix)(epsilon) with N integer and epsilon > -N; each of these complex Hamiltonians exhibits a phase transition at epsilon = 0. These PT symmetric theories may be viewed as analytic continuations of conventional theories from real to complex phase space. (C) 1999 American Institute of Physics. [S0022-2488(99)00105-X]. C1 Washington Univ, Dept Phys, St Louis, MO 63130 USA. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. Clark Atlanta Univ, CTSPS, Atlanta, GA 30314 USA. RP Bender, CM (reprint author), Washington Univ, Dept Phys, St Louis, MO 63130 USA. RI Boettcher, Stefan/G-2640-2010 OI Boettcher, Stefan/0000-0003-1273-6771 NR 18 TC 649 Z9 654 U1 11 U2 51 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0022-2488 J9 J MATH PHYS JI J. Math. Phys. PD MAY PY 1999 VL 40 IS 5 BP 2201 EP 2229 DI 10.1063/1.532860 PG 29 WC Physics, Mathematical SC Physics GA 188XB UT WOS:000079873600001 ER PT J AU Ichinose, S Ikeda, N AF Ichinose, S Ikeda, N TI Weyl anomaly in higher dimensions and Feynman rules in coordinate space SO JOURNAL OF MATHEMATICAL PHYSICS LA English DT Article ID NONLINEAR SIGMA-MODELS; PATH-INTEGRAL MEASURE; CONFORMAL ANOMALIES; TRACE ANOMALIES; GRAPHICAL REPRESENTATION; LOOP CALCULATIONS; GAUGE-THEORIES; COCYCLES; CLASSIFICATION; INVARIANTS AB An algorithm to obtain the Weyl anomaly in higher dimensions is presented. It is based on the heat-kernel method. Feynman rules, such as the vertex rule and the propagator rule, are given in (regularized) coordinate space. A graphical calculation is introduced. The six-dimensional scalar-gravity theory is taken as an example, and its explicit result is obtained. (C) 1999 American Institute of Physics. [S0022-2488(99)01805-8]. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Kyoto Univ, Math Sci Res Inst, Kyoto 60601, Japan. RP Ichinose, S (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RI Ichinose, Shoichi/E-8277-2013 NR 47 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0022-2488 J9 J MATH PHYS JI J. Math. Phys. PD MAY PY 1999 VL 40 IS 5 BP 2259 EP 2290 DI 10.1063/1.532863 PG 32 WC Physics, Mathematical SC Physics GA 188XB UT WOS:000079873600004 ER PT J AU Nolte, J Wagner, HG Sears, TJ Temps, F AF Nolte, J Wagner, HG Sears, TJ Temps, F TI The far-infrared laser magnetic resonance spectrum of CH2F SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID ASYMMETRIC-TOP MOLECULES; ROTATIONAL SPECTRUM; MICROWAVE-SPECTRUM; DIODE-LASER; SPECTROSCOPY; HCO; TRANSITIONS; LINE; BAND; HO2 AB Far-infrared laser magnetic resonance (FIR-LMR) spectra due to the CH2F radical have been recorded on seven laser Lines at wavelengths between 301 and 568 mu m. Observed resonances were assigned to fine and hyperfine components of pure rotational transitions of CH2F in the ground vibrational state and the first excited state of the nu(4) out-of-plane bending mode. All assigned transitions obey a-dipole selection rules. The data were combined with previously reported microwave results (Y. Endo, C. Yamada, S. Saito, and E. Hirota, J. Chern. Phys. 79, 1605 (1983)) and subjected to a least-squares fit to determine the parameters of the effective Hamiltonian describing the nu(4) = 0 and 1 vibrational levels of the CH2F radical. (C) 1999 Academic Press. C1 Max Planck Inst Stromungsforsch, D-37073 Gottingen, Germany. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Univ Kiel, Inst Phys Chem, D-24098 Kiel, Germany. RP Nolte, J (reprint author), Max Planck Inst Stromungsforsch, Bunsenstr 10, D-37073 Gottingen, Germany. RI Sears, Trevor/B-5990-2013 OI Sears, Trevor/0000-0002-5559-0154 NR 33 TC 6 Z9 6 U1 0 U2 2 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD MAY PY 1999 VL 195 IS 1 BP 43 EP 53 DI 10.1006/jmsp.1999.7813 PG 11 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 189UN UT WOS:000079924700004 ER EF