FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Yu, KM Shan, W Glover, CJ Ridgway, MC Wong, WS Yang, W AF Yu, KM Shan, W Glover, CJ Ridgway, MC Wong, WS Yang, W TI Local structures of free-standing AlxGa1-xN thin films studied by extended x-ray absorption fine structure SO APPLIED PHYSICS LETTERS LA English DT Article ID RANDOM SEMICONDUCTOR ALLOYS; RANDOM SOLID-SOLUTIONS; GROUP-III-NITRIDES; LENGTH MISMATCH; EXAFS; GA1-XINXAS AB Local structural information for the first two atomic shells surrounding Ga atoms in free standing AlxGa1-xN alloy films has been obtained by extended x-ray absorption fine structure spectroscopy. For an AlN mole fraction ranging from 0 to 0.6, we found that the first shell Ga-N bond length had only a weak composition dependence, roughly one quarter of that predicted by Vegard's Law. In the second shell, the Ga-Ga bond length was significantly longer than that of Ga-Al (Delta similar to 0.04-0.065 Angstrom). A bond-type specific composition dependence was observed for the second shell cation-cation distances. While the composition dependence of the Ga-Ga bond length is similar to 70% of that predicted by Vegard's Law, the Ga-Al bond length was essentially composition independent. These results suggested that local strain in AlxGa1-xN was also accommodated by lattice distortion in the Al cation sublattice. (C) 1999 American Institute of Physics. [S0003-6951(99)03852-8]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Mat Sci Lab, Ctr Adv Mat, Berkeley, CA 94720 USA. Australian Natl Univ, Res Sch Phys Sci, Dept Elect Mat Engn, Canberra, ACT, Australia. Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. Honeywell Technol Ctr, Plymouth, MN 55420 USA. RP Yu, KM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Mat Sci Lab, Ctr Adv Mat, Berkeley, CA 94720 USA. RI Yu, Kin Man/J-1399-2012; Ridgway, Mark/D-9626-2011 OI Yu, Kin Man/0000-0003-1350-9642; Ridgway, Mark/0000-0002-0642-0108 NR 25 TC 13 Z9 13 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 DEC 27 PY 1999 VL 75 IS 26 BP 4097 EP 4099 DI 10.1063/1.125548 PG 3 WC Physics, Applied SC Physics GA 269YH UT WOS:000084504700017 ER PT J AU Liliental-Weber, Z Benamara, M Swider, W Washburn, J Grzegory, I Porowski, S Lambert, DJH Eiting, CJ Dupuis, RD AF Liliental-Weber, Z Benamara, M Swider, W Washburn, J Grzegory, I Porowski, S Lambert, DJH Eiting, CJ Dupuis, RD TI Mg-doped GaN: Similar defects in bulk crystals and layers grown on Al2O3 by metal-organic chemical-vapor deposition SO APPLIED PHYSICS LETTERS LA English DT Article ID ALUMINUM NITRIDE; OXYGEN; POLYTYPOIDS AB Defects were observed in GaN:Mg grown on sapphire substrates using metal-organic chemical-vapor deposition (MOCVD) with Mg-delta doping similar to those previously observed in bulk GaN:Mg grown from Ga solution under high hydrostatic pressure of nitrogen. Pyramidal defects (pinholes) with (<1(1)over bar>00) hexagonal facets on the (0001) base plane and six {11(2) over bar 2} side facets, and defects with a rectangular shape also delineated by planar facets on the basal (0001) planes, were observed for growth with Ga polarity for both of these very different growth methods. The Mg dopant is apparently responsible for their formation since the oxygen concentration in the MOCVD-grown samples was orders of magnitude lower than in the bulk samples. Mg segregation on these planes apparently does not allow uniform continuous growth on these planes leading to these hollow defects. Some defects in the heterolayers also develop into longer nanotubes elongated along the c axis. Change of polarity from Ga to N followed by a change back to Ga polarity also resulted in formation of planar defects previously observed in bulk samples for growth with N polarity. (C) 1999 American Institute of Physics. [S0003-6951(99)01850-1]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Polish Acad Sci, High Pressure Res Ctr Unipress, Warsaw, Poland. Univ Texas, Microelect Res Ctr, Austin, TX 78712 USA. RP Liliental-Weber, Z (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RI Liliental-Weber, Zuzanna/H-8006-2012 NR 18 TC 63 Z9 63 U1 2 U2 22 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 DEC 27 PY 1999 VL 75 IS 26 BP 4159 EP 4161 DI 10.1063/1.125568 PG 3 WC Physics, Applied SC Physics GA 269YH UT WOS:000084504700038 ER PT J AU te Velthuis, SGET Felcher, GP Jiang, JS Inomata, A Nelson, CS Berger, A Bader, SD AF te Velthuis, SGET Felcher, GP Jiang, JS Inomata, A Nelson, CS Berger, A Bader, SD TI Magnetic configurations in exchange-biased double superlattices SO APPLIED PHYSICS LETTERS LA English DT Article ID 100 SUPERLATTICES; INTERFACES; BILAYERS; FILMS; ANISOTROPY; LAYER; MODEL AB The layer-by-layer magnetization of a "double-superlattice" Fe/Cr(211) exchange-bias junction was determined by polarized neutron reflectometry. An n-layered [Fe/Cr](n) antiferromagnetic (AF) superlattice is coupled with an m-layered [Fe/Cr](m) ferromagnetic (F) superlattice, to provide a controlled exchange bias. In low magnetic fields, the magnetizations of the two superlattices are collinear. The two magnetized states (along or opposite to the bias field) differ only in the relative orientation of the F and adjacent AF layer. At higher fields, the AF moments flop to the direction perpendicular to the applied field. The structure, thus determined, explains the magnitude of the bias field. (C) 1999 American Institute of Physics. [S0003-6951(99)03052-1]. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. EM tevelthuis@anl.gov RI te Velthuis, Suzanne/I-6735-2013; Berger, Andreas/D-3706-2015; Bader, Samuel/A-2995-2013 OI te Velthuis, Suzanne/0000-0002-1023-8384; Berger, Andreas/0000-0001-5865-6609; NR 21 TC 34 Z9 34 U1 1 U2 1 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 DEC 27 PY 1999 VL 75 IS 26 BP 4174 EP 4176 DI 10.1063/1.125573 PG 3 WC Physics, Applied SC Physics GA 269YH UT WOS:000084504700043 ER PT J AU Findikoglu, AT Jia, QX Kwon, C Reagor, DW Kaduchak, G Rasmussen, KO Bishop, AR AF Findikoglu, AT Jia, QX Kwon, C Reagor, DW Kaduchak, G Rasmussen, KO Bishop, AR TI Comparative study of broadband electrodynamic properties of single-crystal and thin-film strontium titanate SO APPLIED PHYSICS LETTERS LA English DT Article ID DIELECTRIC LOSS; SRTIO3 AB We have used a coplanar waveguide structure to study broadband electrodynamic properties of single-crystal and thin-film strontium titanate. We have incorporated both time- and frequency-domain measurements to determine small-signal effective refractive index and loss tangent as functions of frequency (up to 4 GHz), dc bias (up to 10(6) V/m), and cryogenic temperature (17 and 60 K). The large-signal impulse response of the devices and the associated phenomenological nonlinear wave equation illustrate how dissipation and nonlinearity combine to produce the overall response in the large-signal regime. (C) 1999 American Institute of Physics. [S0003-6951(99)02952-6]. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Findikoglu, AT (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RI Rasmussen, Kim/B-5464-2009; Jia, Q. X./C-5194-2008 OI Rasmussen, Kim/0000-0002-4029-4723; NR 16 TC 1 Z9 1 U1 0 U2 0 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 DEC 27 PY 1999 VL 75 IS 26 BP 4189 EP 4191 DI 10.1063/1.125578 PG 3 WC Physics, Applied SC Physics GA 269YH UT WOS:000084504700048 ER PT J AU Cinco, RM Rompel, A Visser, H Aromi, G Christou, G Sauer, K Klein, MP Yachandra, VK AF Cinco, RM Rompel, A Visser, H Aromi, G Christou, G Sauer, K Klein, MP Yachandra, VK TI Comparison of the manganese cluster in oxygen-evolving photosystem II with distorted cubane manganese compounds through X-ray absorption spectroscopy SO INORGANIC CHEMISTRY LA English DT Article ID PHOTOSYNTHETIC WATER OXIDATION; BOND VALENCE SUMS; ELECTRON-PARAMAGNETIC RESONANCE; INDEPENDENT R-0 VALUES; FINE-STRUCTURE; O2-EVOLVING COMPLEX; MULTIPLE-SCATTERING; MODEL COMPLEXES; MN CLUSTER; STATE AB X-ray absorption spectroscopy has been employed to assess the degree of similarity between the oxygen-evolving complex (OEC) in photosystem II (PS II) and a family of synthetic manganese complexes containing the distorted cubane [Mn4O3X] core (X = benzoate, acetate, methoxide, hydroxide, azide, fluoride, chloride, or bromide). These [Mn-4(mu(3)-O)(3)(mu(3)-X)] cubanes possess C-3 nu symmetry except for the X = benzoate species, which is slightly more distorted with only C-s symmetry. In addition, Mn4O3Cl complexes containing three or six terminal Cl ligands at three of the Mn were included in this study. The Mn K-edge X-ray absorption near edge structure (XANES) from the oxygen-ligated complexes begin to resemble general features of the PS II (S-1 state) spectrum, although the second derivatives are distinct from those in PS II. The extended X-ray absorption fine structure (EXAFS) of these Mn compounds also displays superficial resemblance to that of PS II, but major differences emerge on closer examination of the phases and amplitudes. The most obvious distinction is the smaller magnitude of the Fourier transform (FT) of the PS Il EXAFS compared to the FTs from the distorted cubanes. Curve fitting of the Mn EXAFS spectra verifies the known core structures of the Mn cubanes, and shows that the number of the crucial 2.7 and 3.3 Angstrom Mn-Mn distances differs from that observed in the OEC. The EXAFS method detects small changes in the core structures as X is varied in this series, and serves to exclude the distorted cubane of C-3 nu symmetry as a topological model for the Mn catalytic cluster of the OEC. Instead, the method shows that even more distortion of the cubans framework, altering the ratio of the Mn-Mn distances, is required to resemble the Mn cluster in PS II. C1 Indiana Univ, Dept Chem, Bloomington, IN 47405 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Melvin Calvin Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Christou, G (reprint author), Indiana Univ, Dept Chem, Bloomington, IN 47405 USA. RI Aromi, Guillem/I-2483-2015; Christou, George /A-3072-2014 OI Aromi, Guillem/0000-0002-0997-9484; FU NIGMS NIH HHS [R01 GM055302, R56 GM055302] NR 76 TC 66 Z9 66 U1 0 U2 16 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 DEC 27 PY 1999 VL 38 IS 26 BP 5988 EP 5998 DI 10.1021/ic991003j PG 11 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 270FU UT WOS:000084525400011 PM 11671305 ER PT J AU Suszcynsky, DM Strabley, R Roussel-Dupre, R Symbalisty, EMD Armstrong, RA Lyons, WA Taylor, M AF Suszcynsky, DM Strabley, R Roussel-Dupre, R Symbalisty, EMD Armstrong, RA Lyons, WA Taylor, M TI Video and photometric observations of a sprite in coincidence with a meteor-triggered jet event SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ELECTROSTATIC THUNDERCLOUD FIELDS; BLUE JETS; ELECTROMAGNETIC PULSES; AIRCRAFT CAMPAIGN; LOWER IONOSPHERE; IONIZATION; EMISSIONS AB Video and photometric observations of a meteor-triggered "jet" event in association with the occurrence of a sprite were collected during the SPRITES '98 campaign. The event raises interest in the question of possible meteoric triggering of upper atmospheric transients as originally suggested by Muller [1995]. The event consisted of three stages: (1) the observation of a moderately bright meteor, (2) the development of a sprite in the immediate vicinity of the meteor as the meteor reached no lower than similar to 70 km altitude, and (3) a slower-forming jet of luminosity that appeared during the late stages of the sprite and propagated back up the ionization trail of the meteor. The event is analyzed in terms of its geometry, its relevance to the meteor, and the implications to existing theories for sprite formation. C1 Mission Res Corp, Nashua, NH 03062 USA. FMA Res Inc, Ft Collins, CO USA. Los Alamos Natl Lab, Atmostpher & Climate Sci Grp, Los Alamos, NM 87545 USA. Los Alamos Natl Lab, Space & Atmostpher Sci Grp, Los Alamos, NM 87545 USA. Utah State Univ, Space Dynam Lab, Logan, UT 84322 USA. RP Suszcynsky, DM (reprint author), Mission Res Corp, Suite 302,1 Tara Blvd, Nashua, NH 03062 USA. EM dsuszcynsky@lanl.gov; rroussel-dupre@lanl.gov; esymbalisty@lanl.gov; mtaylor@cc.usu.gov NR 31 TC 16 Z9 16 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 27 PY 1999 VL 104 IS D24 BP 31361 EP 31367 DI 10.1029/1999JD900962 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 273DQ UT WOS:000084692900034 ER PT J AU Lenkeit, B AF Lenkeit, B CA CERES Collaboration TI Recent results from Pb-Au collisions at 158 GeV/c per nucleon obtained with the CERES spectrometer SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate ID CENTRAL PB+PB COLLISIONS; PAIR PRODUCTION AB During the 1996 lead run time, CERES has accumulated 42 million events, corresponding to a factor of 5 more statistics than in 1995 and 2.5 million events of a special photon-run. We report on the results of the low-mass e(+)e(-)-pair analysis. Since the most critical item is the poor signal-to-background ratio we also discuss the understanding of this background, in absolute terms, with the help of a detailed Monte Carlo simulation. We show preliminary results of the photon analysis and summarize the results of the hadron analysis preliminarily reported on already at QM'97 [1]. C1 GSI Darmstadt, D-6100 Darmstadt, Germany. JINR, Dubna, Russia. CERN, CH-1211 Geneva 23, Switzerland. Max Planck Inst Kernphys, D-69117 Heidelberg, Germany. Univ Heidelberg, Heidelberg, Germany. Weizmann Inst Sci, IL-76100 Rehovot, Israel. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Lenkeit, B (reprint author), GSI Darmstadt, D-6100 Darmstadt, Germany. NR 16 TC 52 Z9 53 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 23C EP 32C DI 10.1016/S0375-9474(99)00437-6 PG 10 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600004 ER PT J AU Sikler, F AF Sikler, F CA NA49 collaboration TI Hadron production in nuclear collisions from the NA49 experiment at 158GeV/c center dot A SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate ID PB+PB COLLISIONS AB With its large acceptance and particle identification coverage the NA49 experiment (Fig. 1) can study hadron production in a wide range of high energy reactions [1]. Originally aimed at examining central Pb+Pb collisions for signatures of quark-gluon plasma formation, the scope of the experiment has been enhanced with the systematic study of impact parameter and projectile size dependence, as well as the inclusion. of the more elementary p+p and p+A interactions. The question is: are predicted signals of the quarkgluon plasma observed and are there discontinuities which would support the concept of hadronic phase transition?. C1 CERN, CH-1211 Geneva 23, Switzerland. Univ Athens, Dept Phys, Athens, Greece. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Birmingham, Birmingham, W Midlands, England. Slovak Acad Sci, Inst Phys, Bratislava, Slovakia. Res Inst Particle & Nucl Phys, KFKI, Budapest, Hungary. Inst Nucl Phys, Krakow, Poland. Gesell Schwerionenforsch GmbH, D-6100 Darmstadt, Germany. Univ Calif Davis, Davis, CA 95616 USA. Joint Inst Nucl Res, Dubna, Russia. Univ Frankfurt, Fachbereich Phys, D-6000 Frankfurt, Germany. Univ Houston, Houston, TX 77004 USA. Kent State Univ, Kent, OH 44242 USA. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. Univ Marburg, Fachbereich Phys, D-3550 Marburg, Germany. Max Planck Inst Phys, D-80805 Munich, Germany. Inst Nucl Studies, PL-00681 Warsaw, Poland. Univ Warsaw, Inst Expt Phys, Warsaw, Poland. Univ Washington, Nucl Phys Lab, Seattle, WA 98195 USA. Yale Univ, New Haven, CT 06520 USA. Rudjer Boskovic Inst, Zagreb, Croatia. RP Sikler, F (reprint author), CERN, CH-1211 Geneva 23, Switzerland. NR 8 TC 88 Z9 88 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 45C EP 54C DI 10.1016/S0375-9474(99)00439-X PG 10 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600006 ER PT J AU Hofman, DJ AF Hofman, DJ CA E917 collaboration TI Results from experiment E917 for Au+Au collisions at the AGS SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate ID GEV/C AB The effects of baryon stopping and its resulting energy deposition on the dynamics of Au + Au collisions at 6, 8 and 10.8 GeV/nucleon are explored with recent results from the AGS experiment E917. Current analyses of stopping, collective flow; signals and HBT parameters are presented. Strangeness and anti-baryon production is examined using the yields of anti-lambdas and anti-protons. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Hofman, DJ (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 12 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 75C EP 81C DI 10.1016/S0375-9474(99)00442-X PG 7 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600009 ER PT J AU Rai, G AF Rai, G CA E895 Collaboration TI Results from the experiment E895 at the BNL AGS SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate ID HEAVY-ION COLLISIONS; NUCLEAR-EQUATION; EXPANSION; EMISSION; MATTER; STATE; FLOW AB We present some of the latest results from the E895 experiment conducted at the BNL ACS accelerator. Au+Au collisions were recorded ly the EOS Time Projection Chamber (TPC) at beam energies of 2, 4, 6, and 8 A GeV. The TPC detector permitted the reconstruction of individual collision events with almost 4 pi acceptance and good particle indentification. This capability allowed E895 to study global observables and two particle correlations with respect to symmetries of the client. Flow excitation functions are examined and discussed in the context of the Nuclear Equation of Slate. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Rai, G (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 22 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 162C EP 169C DI 10.1016/S0375-9474(99)00450-9 PG 8 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600017 ER PT J AU Caines, H Albergo, S Bellwied, R Bennett, M Boemi, D Bonner, B Caccia, Z Christie, W Cina, G Costa, S Crawford, H Cronqvist, M Debbe, R Engelage, J Flores, I Greiner, L Hallman, T Hoffman, G Huang, H Humanic, TJ Igo, G Insolia, A Jensen, P Judd, E Kainz, K Kaplan, M Kelly, S Kotov, I Kunde, G Lindstrom, P Ljubicic, T Llope, W Lo Curto, G Longacre, R Lynn, D Madansky, L Mahzeh, N Milosevich, Z Mitchell, JT Mitchell, J Nehmeh, S Nociforo, C Paganis, S Pandey, SU Potenza, R Platner, E Riley, P Russ, D Saulys, A Schambach, J Sheen, J Stokley, C Sugarbaker, E Takahashi, J Tang, J Trentalange, S Tricomi, A Tull, C Tuve, C Whitfield, J Wilson, K AF Caines, H Albergo, S Bellwied, R Bennett, M Boemi, D Bonner, B Caccia, Z Christie, W Cina, G Costa, S Crawford, H Cronqvist, M Debbe, R Engelage, J Flores, I Greiner, L Hallman, T Hoffman, G Huang, H Humanic, TJ Igo, G Insolia, A Jensen, P Judd, E Kainz, K Kaplan, M Kelly, S Kotov, I Kunde, G Lindstrom, P Ljubicic, T Llope, W Lo Curto, G Longacre, R Lynn, D Madansky, L Mahzeh, N Milosevich, Z Mitchell, JT Mitchell, J Nehmeh, S Nociforo, C Paganis, S Pandey, SU Potenza, R Platner, E Riley, P Russ, D Saulys, A Schambach, J Sheen, J Stokley, C Sugarbaker, E Takahashi, J Tang, J Trentalange, S Tricomi, A Tull, C Tuve, C Whitfield, J Wilson, K TI First results from the H-0 di-baryon search and hyperon production measurements by the AGS Experiment 896. SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate ID H-DIBARYON; COLLISIONS AB The AGS Experiment 896 was designed to study strangeness production in Au-Au collisions at 11.6A GeV/c, in particular the formation of a six-quark di-baryon the H-0. Heavy ion collisions provide favorable conditions for the H-0 formation either via coalescence of two Lambda particles (owing to the large Lambda production cross section) or direct production from the possible formation of a quark-gluon plasma. E896 also measured strange meson and baryon distributions from mid-rapidity. Preliminary results from this experiment are presented as well as details of the expected sensitivity for the H-0 search. C1 Ohio State Univ, Columbus, OH 43210 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Calif Los Angeles, Los Angeles, CA 90095 USA. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Univ Catania, I-95129 Catania, Italy. Johns Hopkins Univ, Baltimore, MD 21218 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Space Sci Lab, Berkeley, CA 94720 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Rice Univ, Houston, TX 77251 USA. Univ Texas, Austin, TX 78712 USA. Wayne State Univ, Detroit, MI 48201 USA. Yale Univ, New Haven, CT 06520 USA. RP Caines, H (reprint author), Ohio State Univ, Columbus, OH 43210 USA. RI Takahashi, Jun/B-2946-2012; Insolia, Antonio/M-3447-2015; TUVE', Cristina/P-3933-2015 OI Takahashi, Jun/0000-0002-4091-1779; Insolia, Antonio/0000-0002-9040-1566; TUVE', Cristina/0000-0003-0739-3153 NR 11 TC 5 Z9 5 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 170C EP 176C DI 10.1016/S0375-9474(99)00451-0 PG 7 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600018 ER PT J AU Bass, SA Bleicher, M Cassing, W Dumitru, A Drescher, HJ Eskola, KJ Gyulassy, M Kharzeev, D Kovchegov, YV Lin, Z Molnar, D Ollitrault, JY Pratt, S Schlei, BR Sorge, H Rafelski, J Rapp, R Rischke, DH Schaffner, JB Snigirev, AM Srivastava, DK Stachel, J Teaney, D Thews, R Vance, SE Vitev, I Vogt, R Wang, XN Zhang, B Zimanyi, J AF Bass, SA Bleicher, M Cassing, W Dumitru, A Drescher, HJ Eskola, KJ Gyulassy, M Kharzeev, D Kovchegov, YV Lin, Z Molnar, D Ollitrault, JY Pratt, S Schlei, BR Sorge, H Rafelski, J Rapp, R Rischke, DH Schaffner, JB Snigirev, AM Srivastava, DK Stachel, J Teaney, D Thews, R Vance, SE Vitev, I Vogt, R Wang, XN Zhang, B Zimanyi, J TI Last call for RHIC predictions SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate ID HEAVY-ION COLLISIONS; QUARK-GLUON-PLASMA; NUCLEUS-NUCLEUS COLLISIONS; RADIATIVE ENERGY-LOSS; WEIZSACKER-WILLIAMS FIELD; PARTON CASCADE MODELS; SPACE-TIME EVOLUTION; PB+PB COLLISIONS; HADRONIC MATTER; MONTE-CARLO C1 Duke Univ, Dept Phys, Durham, NC 27706 USA. Goethe Univ Frankfurt, Inst Theor Phys, D-6000 Frankfurt, Germany. Univ Giessen, Inst Theor Phys, Giessen, Germany. Yale Univ, Dept Phys, New Haven, CT 06520 USA. Univ Nantes, Nantes, France. Univ Jyvaskyla, Jyvaskyla, Finland. Columbia Univ, Dept Phys, New York, NY 10027 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Brookhaven Natl Lab, RBRC, Upton, NY 11973 USA. Univ Minnesota, Dept Phys, Minneapolis, MN 55455 USA. TAM, Dept Phys, College Stn, TX USA. Michigan State Univ, Dept Phys, E Lansing, MI 48824 USA. Los Alamos Natl Lab, Theor Div, Los Alamos, NM USA. SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. Univ Arizona, Dept Phys, Tucson, NM USA. Brookhaven Natl Lab, RIKEN, Res Ctr, Upton, NY 11973 USA. Moscow MV Lomonosov State Univ, Inst Nucl Phys, Moscow, Russia. Ctr Variable Energy Cyclotron, Kolkata, W Bengal, India. Heidelberg Univ, Dept Phys, Heidelberg, Germany. LBNL, Div Nucl Sci, Berkeley, CA USA. RMKI, Budapest, Hungary. RP Duke Univ, Dept Phys, Durham, NC 27706 USA. RI Ollitrault, Jean-Yves/B-3709-2010; Bleicher, Marcus/A-2758-2010; Snigirev, Alexander/D-8912-2012; Rafelski, Johann/E-4678-2013 OI Ollitrault, Jean-Yves/0000-0001-6037-7975; NR 146 TC 48 Z9 48 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 EI 1873-1554 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 205C EP 260C DI 10.1016/S0375-9474(99)00456-X PG 56 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600023 ER PT J AU Baltz, AJ AF Baltz, AJ TI Coherent electromagnetic heavy ion reactions: (1) exact treatment of pair production and ionization; (2) mutual Coulomb dissociation SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate ID ELECTRON-CAPTURE; FIXED TARGETS; SULFUR IONS; COLLISIONS AB Sense recent theoretical results on coherent electromagnetic processes in ultrarelativistic heavy ion reactions are surveyed. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Baltz, AJ (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 23 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 317C EP 320C DI 10.1016/S0375-9474(99)00462-5 PG 4 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600029 ER PT J AU Poskanzer, AM Voloshin, SA AF Poskanzer, AM Voloshin, SA CA NA49 Collaboration TI Centrality dependence of directed and elliptic flow at the SPS SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate ID COLLISIONS; SIGNATURE AB New data with a minimum Lias trigger for 158 GeV/nucleon Pb+Pb have been analyzed. Directed and elliptic flow as a function of rapidity of the particles and centrality of the collision are presented. The centrality dependence of the ratio of elliptic flow to the initial space elliptic anisotropy is compared to models. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Poskanzer, AM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RI Voloshin, Sergei/I-4122-2013 NR 11 TC 28 Z9 29 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 341C EP 344C DI 10.1016/S0375-9474(99)00468-6 PG 4 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600035 ER PT J AU Cooper, GE AF Cooper, GE CA NA49 Collaboration TI Stopping: from peripheral to central nuclear collisions st the SPS SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate AB New results on baryon stopping at the CERN SPS! measured Ly the inclusive net proton (p-IS) rapidity distribution, are presented for centrality selected Pb+Pb and Pb+Pb, as well as minimum bias p+p collisions. A smooth evolution in the degree of stopping is observed when going from small to large systems, with the greatest stopping in the most central p+Pb collisions. On the other hand, longitudinal distributions of produced particles vary little with the size of the system, and the total yield of pions scales approximately with the number of participating nucleons. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Cooper, GE (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 6 TC 17 Z9 17 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 362C EP 365C DI 10.1016/S0375-9474(99)00473-X PG 4 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600040 ER PT J AU Tannenbaum, MJ AF Tannenbaum, MJ CA E802 Collaboration TI Centrality definition using mid-rapidity E-T distributions from p + Be to Au + Au at AGS energies SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate ID TRANSVERSE ENERGY-DISTRIBUTIONS; 14.6A GEV/C; MULTIPLICITY DISTRIBUTIONS; COLLISIONS; INTERMITTENCY; O-16+CU AB Measurements by the E802 Collaboration of the A-dependence and pseudorapidity interval (Sri) dependence of mid-rapidity Er distributions in a half-azimuth electromagnetic calorimeter are presented for p+Be, p+Au, O+Cu, Si+Au and Au+Au collisions at the BNL-AGS. The issues addressed are 1) whether the shapes of the upper edges of the Er distributions vary with delta eta similarly to the variation in shapes of mid-rapidity charged particle distributions and 2) hom small a delta eta interval would still give a meaningful characterization of the 'nuclear geometry' of a reaction. A new way of plotting ET distributions was found from which the reaction dynamics could be read directly. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. RP Tannenbaum, MJ (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. OI Tannenbaum, Michael/0000-0002-8840-5314 NR 6 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 411C EP 414C DI 10.1016/S0375-9474(99)00485-6 PG 4 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600052 ER PT J AU Soltz, RA Baker, M Lee, JH AF Soltz, RA Baker, M Lee, JH TI Systematic investigation of two-pion correlations at the AGS SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate ID QUARK-GLUON PLASMA; COLLISIONS; INTERFEROMETRY AB We summarize recent HBT results from the Henry Higgins and Forward Spectrometers of BNL E866. These measurements are for pions of both signs in the mid- and forward-rapidity regions. 1.2 < Y < 2.3, for a range of mean pair momenta, 0.1 < k(T) < 0.5, spanning the full range of system-size and centrality from peripheral Si+Al to central Au+Au. All particles are identified as pions by time-of-Right to better than 3 sigma. Source radii are fit using Bertsch-Pratt and Yano-Koonin parameterizations. The transverse momentum dependences imply transverse expansion in all systems. The radii scaling with centrality is consistent with both geometric and freeze-out interpretations. Comparisons to geometric overlap of the projectile-target system also give evidence for expansion. Emission durations are in the range, 2-4 fm/c, and for the first time show a linear correlation with geometric size. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Soltz, RA (reprint author), Univ Calif Lawrence Livermore Natl Lab, 7000 East Ave,L-50, Livermore, CA 94550 USA. NR 14 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 439C EP 443C DI 10.1016/S0375-9474(99)00492-3 PG 5 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600059 ER PT J AU Lo Curto, G Albergo, S Bellwied, R Bennett, M Boemi, D Bonner, B Caccia, Z Caines, H Christie, W Cina, G Costa, S Crawford, H Cronqvist, M Debbe, R Engelage, J Flores, I Greiner, L Hallman, T Hoffman, G Huang, H Humanic, TJ Igo, G Insolia, A Jensen, P Judd, E Kainz, K Kaplan, M Kelly, S Kotov, I Kunde, G Lindstrom, P Ljubicic, T Llope, W Longacre, R Lynn, D Madansky, L Mahzeh, N Milosevich, Z Mitchell, JT Mitchell, J Nehmeh, S Nociforo, C Paganis, S Pandey, SU Potenza, R Platner, E Riley, P Russ, D Saulys, A Schambach, J Sheen, J Stokley, C Sugarbaker, E Takahashi, J Tang, J Trentalange, S Tricomi, A Tull, C Tuve, C Whitfield, J Wilson, K AF Lo Curto, G Albergo, S Bellwied, R Bennett, M Boemi, D Bonner, B Caccia, Z Caines, H Christie, W Cina, G Costa, S Crawford, H Cronqvist, M Debbe, R Engelage, J Flores, I Greiner, L Hallman, T Hoffman, G Huang, H Humanic, TJ Igo, G Insolia, A Jensen, P Judd, E Kainz, K Kaplan, M Kelly, S Kotov, I Kunde, G Lindstrom, P Ljubicic, T Llope, W Longacre, R Lynn, D Madansky, L Mahzeh, N Milosevich, Z Mitchell, JT Mitchell, J Nehmeh, S Nociforo, C Paganis, S Pandey, SU Potenza, R Platner, E Riley, P Russ, D Saulys, A Schambach, J Sheen, J Stokley, C Sugarbaker, E Takahashi, J Tang, J Trentalange, S Tricomi, A Tull, C Tuve, C Whitfield, J Wilson, K TI Strange and multi-strange baryon measurement in Au plus Au collisions at 11.6A(GeV/c) with the silicon drift detector array from the AGS experiment E896 SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate AB The main purpose of experiment E896 is to study the production of strange hadrons, in particular the predicted six-quark di-baryon, the H-0. The placement of the silicon drift detector array (SDDA) close to the target in a 6.2T magnetic field is optimized for the reconstruction of a short lived H-0 as well as of strange baryons (Lambda, <(Lambda)over bar>, Xi(-)). Simulations show that with the present data sample a detailed study of the A and Xi(-) yields and distributions may be performed and a clear <(Lambda)over bar> signal might be detected. Simulations as well as a preliminary analysis of the SDDA data will be presented. C1 Ohio State Univ, Columbus, OH 43210 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Univ Catania, Catania, Italy. Johns Hopkins Univ, Baltimore, MD 21218 USA. Lawrence Berkeley Lab, Space Sci Lab, Berkeley, CA USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Rice Univ, Houston, TX 77251 USA. Univ Texas, Austin, TX 78712 USA. Wayne State Univ, Detroit, MI 48202 USA. Yale Univ, New Haven, CT 06520 USA. RP Lo Curto, G (reprint author), Ohio State Univ, Columbus, OH 43210 USA. RI Takahashi, Jun/B-2946-2012; Insolia, Antonio/M-3447-2015; TUVE', Cristina/P-3933-2015 OI Takahashi, Jun/0000-0002-4091-1779; Insolia, Antonio/0000-0002-9040-1566; TUVE', Cristina/0000-0003-0739-3153 NR 10 TC 1 Z9 1 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 489C EP 492C DI 10.1016/S0375-9474(99)00504-7 PG 4 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600071 ER PT J AU van Hecke, H Sorge, H Xu, N AF van Hecke, H Sorge, H Xu, N TI Evidence of early multi-strange hadron freeze-out in high energy nuclear collisions SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate ID HEAVY-ION COLLISIONS; PB COLLISIONS; PHASE-TRANSITION; EXPANSION; MATTER; EQUILIBRATION; PLASMA; GEV/C C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. SUNY Stony Brook, Dept Phys, Stony Brook, NY 11794 USA. LBNL, Div Nucl Sci, Berkeley, CA 94720 USA. RP van Hecke, H (reprint author), Univ Calif Los Alamos Natl Lab, MS H846, Los Alamos, NM 87545 USA. NR 25 TC 14 Z9 14 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 493C EP 496C DI 10.1016/S0375-9474(99)00505-9 PG 4 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600072 ER PT J AU Fujii, H Kharzeev, D AF Fujii, H Kharzeev, D TI Interactions of quarkonium at low energies SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate ID HADRONIC TRANSITIONS; STATES; VAN; QCD AB We present two examples of the short-distance QCD calculations for the quarkonium (Phi) interactions; 1) pi Phi elastic and pi Phi -> pi Phi cross sections, and 2) the potential between two Phi's. The former is relevant for the Phi suppression in heavy ion collisions; we find that the corresponding cross sections are very small. For the latter we derive the sum rule which relates the strength of the potential to the energy density of the QCD vacuum. The key starting point in both cases is that the leading operator in the operator product expansion (OPE) for the ion-energy scattering amplitude is the trace of the QCD stress tensor whose matrix elements are unambiguously fixed LS the lon energy theorem. The resonances in the two-pion scalar channel are taken into account as a formfactor. C1 Univ Tokyo, Inst Phys, Tokyo 1538902, Japan. Brookhaven Natl Lab, RIKEN, BNL, Upton, NY 11973 USA. RP Fujii, H (reprint author), Univ Tokyo, Inst Phys, 4-6-1 Komaba, Tokyo 1538902, Japan. NR 16 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 542C EP 545C DI 10.1016/S0375-9474(99)00517-5 PG 4 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600084 ER PT J AU Leitch, MJ Lee, WM Beddo, ME Brown, CN Carey, TA Chang, TH Cooper, WE Gagliardi, CA Garvey, GT Geesaman, DF Hawker, EA He, XC Isenhower, LD Kaufman, SB Kaplan, DM Koetke, DD McGaughey, PL Moss, JM Mueller, BA Papavassiliou, V Peng, JC Petitt, G Reimer, PE Sadler, ME Stankus, PW Sondheim, WE Towell, RS Tribble, RE Vasiliev, MA Webb, JC Willis, JL Young, GR Christian, A AF Leitch, MJ Lee, WM Beddo, ME Brown, CN Carey, TA Chang, TH Cooper, WE Gagliardi, CA Garvey, GT Geesaman, DF Hawker, EA He, XC Isenhower, LD Kaufman, SB Kaplan, DM Koetke, DD McGaughey, PL Moss, JM Mueller, BA Papavassiliou, V Peng, JC Petitt, G Reimer, PE Sadler, ME Stankus, PW Sondheim, WE Towell, RS Tribble, RE Vasiliev, MA Webb, JC Willis, JL Young, GR Christian, A CA FNAL E866 NuSea Collaboration TI J/psi and psi ' suppression in p-A collisions at 800 GeV/c SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate ID DEPENDENCE C1 LANL, Los Alamos, NM 87545 USA. Abilene Christian Univ, Abilene, TX 79699 USA. IIT, Chicago, IL 60616 USA. ORNL, Oak Ridge, TN USA. Texas A&M Univ, College Stn, TX 77843 USA. RP LANL, Los Alamos, NM 87545 USA. EM leitch@lanl.gov; muller@phy.duke.edu RI Reimer, Paul/E-2223-2013 NR 18 TC 2 Z9 2 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 EI 1873-1554 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 554C EP 557C DI 10.1016/S0375-9474(99)00520-5 PG 4 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600087 ER PT J AU Gale, C Jeon, S Kapusta, J AF Gale, C Jeon, S Kapusta, J TI Drell-Yan and J/psi production in high energy proton-nucleus and nucleus-nucleus collisions SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate ID QUARK-GLUON PLASMA; J-PSI-SUPPRESSION; CROSS-SECTIONS; DEPENDENCE; PHOTOPRODUCTION; HADRON; GEV/C AB The distributions of outgoing protons and charged hadrons in high energy proton-nucleus collisions are described rather well by a linear extrapolation from proton-proton collisions. This linear extrapolation is applied to precisely measured Drell-Yan cross sections for 800 GeV protons incident on a variety of nuclear targets. The deviation from linear scaling in the atomic number A can be accounted for by energy degradation of the proton as it passes through the nucleus if account is taken of the time delay of particle production due to quantum coherence. We infer an average proper coherence time of 0.4+/-0.1 fm/c. Then we apply the linear extrapolation to measured J/psi production cross sections for 200 and 450 GeV/c protons incident on a variety of nuclear targets. Our analysis takes into account energy loss of the beam proton, the time delay of particle production due to quantum coherence, and absorption of the J/psi, On nucleons. The best representation is obtained for a coherence time of 0.5 fm/c, which is consistent with Drell-Yan production, and an absorption cross section of 3.6 mb, which is consistent with the value deduced from photoproduction of the J/psi on nuclear targets. Finally, we compare to recent J/psi, data from S+U and Pb+Pb collisions at the SPS. The former are reproduced reasonably well with no new parameters, but not the latter. C1 McGill Univ, Dept Phys, Montreal, PQ H3A 2T8, Canada. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. RP Gale, C (reprint author), McGill Univ, Dept Phys, 3600 Univ St, Montreal, PQ H3A 2T8, Canada. NR 27 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 558C EP 567C DI 10.1016/S0375-9474(99)00521-7 PG 10 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600088 ER PT J AU Kharzeev, D Satz, H Syamtomov, A Zinovjev, G AF Kharzeev, D Satz, H Syamtomov, A Zinovjev, G TI J/psi-photoproduction and the gluon structure of the nucleon SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate ID QUARKONIUM AB Using QCD sum rule method based on the operator product expansion, we calculate the J/psi photoproduction cross section in terms of the gluon distribution function of the nucleon. Comparing the results with the data, we show that experimental behaviour of the cross section correctly reflects the x-dependence of the gluon distribution obtained from deep inelastic scattering. C1 Brookhaven Natl Lab, RIKEN, BNL Inst, Upton, NY 11973 USA. Univ Bielefeld, Fak Phys, D-33501 Bielefeld, Germany. Natl Acad Sci Ukraine, Inst Theoret Phys, UA-252143 Kiev, Ukraine. RP Kharzeev, D (reprint author), Brookhaven Natl Lab, RIKEN, BNL Inst, Upton, NY 11973 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 568C EP 572C DI 10.1016/S0375-9474(99)00522-9 PG 5 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600089 ER PT J AU Ayala, A Jeon, S Kapusta, J AF Ayala, A Jeon, S Kapusta, J TI Coulomb distortion of pi(+)/pi(-) as a tool to determine the fireball radius in central high energy heavy ion collisions SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate ID SINGLE-PARTICLE; DISTRIBUTIONS; SPECTRA; NA49 AB We compute the Coulomb distortion produced by an expanding and highly charged fireball on the spectra of low transverse momenta and mid rapidity pions produced in central high energy heavy ion collisions. We compare to data on Au+Au at 11.6A GeV from E866 at the BNL AGS and of Pb+Pb at 158A GeV from NA44 at the CERN SPS. We match the fireball expansion velocity with the average transverse momentum of protons and find a best fit to the charged pion ratio when the fireball radius is about 10 fm at freeze-out. This value is common to both AGS and SPS data. C1 Natl Autonomous Univ Mexico, Inst Ciencias Nucl, Mexico City 04510, DF, Mexico. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. RP Ayala, A (reprint author), Natl Autonomous Univ Mexico, Inst Ciencias Nucl, Apartado Postal 70-543, Mexico City 04510, DF, Mexico. NR 18 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 573C EP 576C DI 10.1016/S0375-9474(99)00523-0 PG 4 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600090 ER PT J AU Li, Q Pang, Y Xu, N AF Li, Q Pang, Y Xu, N TI Origin of collectivity in heavy ion collisions SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate AB Collective flow observables at SPS and RHIC are studied. The question on the origin of collectivity is addressed by detailed analysis of transport models. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Columbia Univ, Dept Phys, New York, NY 10027 USA. RP Li, Q (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 583C EP 586C DI 10.1016/S0375-9474(99)00525-4 PG 4 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600092 ER PT J AU Srivastava, DK Geiger, K AF Srivastava, DK Geiger, K TI Scaling of particle production with number of participants in high-energy A plus A collisions in the parton-cascade model SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate AB In view of the recent WA98 data of pi(0) spectra from central Pb + Pb collisions at the CERN SPS, we analyze the production of neutral pions for A + A collisions across the periodic table at root s = 17 AGeV and 200 AGeV within the framework of the parton-cascade model for relativistic heavy ion collisions. The multiplicity of the pions (having p(T) > 0.5 GeV) in the central rapidity region, is seen to scale as similar to (N-part)(alpha), where N-part is the number of participating nucleons, which we have approximated as 2A for central collisions of identical nuclei. We argue that the deviation of alpha (similar or equal to 1.2) from unity may have its origin in the multiple scattering suffered by the partons. We also find that the constant of proportionality in the above scaling relation increases substantially in going from SPS to RHIC' energies. This would imply that the (semi)hard partonic activity becomes a much cleaner signal above the soft particle production at the higher energy of RHIC, and thus much less dependent on the (lack of) understanding of the underlying soft physics background. C1 AF Bidhan Nagar, Ctr Variable Energy Cyclotron, Calcutta 700064, W Bengal, India. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Srivastava, DK (reprint author), AF Bidhan Nagar, Ctr Variable Energy Cyclotron, Calcutta 700064, W Bengal, India. NR 6 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 592C EP 595C DI 10.1016/S0375-9474(99)00527-8 PG 4 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600094 ER PT J AU Wang, XN AF Wang, XN TI High p(T) hadron spectra in high-energy heavy-ion collisions SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate ID TRANSVERSE-MOMENTUM; NUCLEAR COLLISIONS; JET AB We calculate the hadron spectra in high-energy pp, pA and AA collisions within a pQCD parton model. Analyses of experimental data show that the modification of the spectra in pA and AA as compared to that in pp collisions is consistent with multiple parton scattering scenario and is dictated by the transition from absorptive soft interaction at low P-T to incoherent hard parton scattering at high p(T). This analysis not only sheds new light on the limits to the physics analysis based on thermal fire-ball models but also provides a more quantitative baseline results on which one can study the effects of parton energy loss in the hadron spectra at high p(T). C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Wang, XN (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, MS 70A-3307, Berkeley, CA 94720 USA. NR 9 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 609C EP 612C DI 10.1016/S0375-9474(99)00531-X PG 4 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600098 ER PT J AU Emel'yanov, V Khodinov, A Klein, SR Vogt, R AF Emel'yanov, V Khodinov, A Klein, SR Vogt, R TI Shadowing effects on particle and transverse energy production SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate ID QUARK PRODUCTION; NUCLEAR; COLLISIONS AB The effect of shadowing on the early state of ultrarelativistic heavy ion collisions and transverse energy production is discussed. Results are presented for RHIC Au+Au collisions at root s(NN) = 200 GeV and LHC Pb+Pb collisions at root s(NN) = 5.5 TeV. C1 Moscow State Tech Univ, Inst Engn Phys, Moscow 115409, Russia. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. RP Emel'yanov, V (reprint author), Moscow State Tech Univ, Inst Engn Phys, Kashirskoe Ave 31, Moscow 115409, Russia. RI KHODINOV, ALEKSANDR/D-6269-2015 OI KHODINOV, ALEKSANDR/0000-0003-3551-5808 NR 12 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 649C EP 652C DI 10.1016/S0375-9474(99)00541-2 PG 4 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600108 ER PT J AU Bennett, MJ AF Bennett, MJ CA PHENIX MVD Grp TI The PHENIX Multiplicity and Vertex Detector SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate AB We describe the design and expected performance of the PHENIX Multiplicity and Vertex Detector (MVD) sub-system of the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Calif Riverside, Riverside, CA 92521 USA. Yonsei Univ, Seoul 120749, South Korea. Univ Alabama, Huntsville, AL 35899 USA. RP Bennett, MJ (reprint author), Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NR 3 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 661C EP 664C DI 10.1016/S0375-9474(99)00544-8 PG 4 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600111 ER PT J AU Nilsson, PB AF Nilsson, PB CA PHENIX Pad Chamber Grp TI The pixel readout system for the PHENIX pad chambers SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate AB A new concept for two-dimensional position readout of wire chambers is described. The basic idea is to use a cathode segmented into small pixels that are read out in specific groups (pads). The electronics is mounted on the outer face of the chamber with a chip-on-board technique, pushing the material thickness to a minimum. The system described here, containing 210 000 readout channels, will be used to read out the pad chambers in the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC). C1 Univ Lund, Dept Phys, Div Cosm & Subat Phys, S-22100 Lund, Sweden. Brookhaven Natl Lab, Upton, NY 11973 USA. McGill Univ, Montreal, PQ, Canada. Oak Ridge Natl Lab, Oak Ridge, TN USA. SUNY Stony Brook, Stony Brook, NY 11794 USA. Vanderbilt Univ, Nashville, TN USA. Weizmann Inst Sci, IL-76100 Rehovot, Israel. RP Nilsson, PB (reprint author), Univ Lund, Dept Phys, Div Cosm & Subat Phys, Box 118, S-22100 Lund, Sweden. NR 1 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 665C EP 668C DI 10.1016/S0375-9474(99)00545-X PG 4 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600112 ER PT J AU Rosati, M AF Rosati, M CA Time Expansion Chamber Grp TI The PHENIX Time Expansion Chamber SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate AB The TEC/TRD subs :stem will track all charged particles and contribute to the particle identification by the measurement of energy loss. The design, construction and testing of the TEC chambers are described. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Iowa State Univ, Ames, IA 50011 USA. Univ Sao Paulo, Sao Paulo, Brazil. Univ Calif Riverside, Riverside, CA 92521 USA. RP Rosati, M (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 669C EP 672C DI 10.1016/S0375-9474(99)00546-1 PG 4 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600113 ER PT J AU Marin, A AF Marin, A CA CERES Collaboration TI First results from the CERES radial TPC SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate AB The CERES/NA45 experiment at the CERN SPS was upgraded in 1998 by the addition of a cylindrical Time Projection Chamber. The aim is to improve the mass resolution of e(+)e(-) pairs in the rho/omega/phi region to Delta m/m < 2%. A progress report is given on the TPC performance during the 1998 commissioning runs (laser rays, beam halo muons, and particles produced by proton/pi and lead beams hitting Pb and Au targets). C1 Joint Inst Nucl Res Dubna, Dubna, Russia. Univ Heidelberg, D-6900 Heidelberg, Germany. GSI Darmstadt, D-6100 Darmstadt, Germany. SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY USA. Weizmann Inst Sci, IL-76100 Rehovot, Israel. Max Planck Inst Kernphys, D-69117 Heidelberg, Germany. ASCR, NPI, Rez, Czech Republic. Brookhaven Natl Lab, Upton, NY 11973 USA. CERN, Geneva, Switzerland. RP Marin, A (reprint author), Joint Inst Nucl Res Dubna, Dubna, Russia. NR 6 TC 11 Z9 11 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 673C EP 676C DI 10.1016/S0375-9474(99)00547-3 PG 4 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600114 ER PT J AU Ackerman, KH Adams, N Adler, N Aluyshin, M Ananeva, MA Anderson, M Averichev, G Bacher, A Balewski, J Balrannikova, O Baudot, J Bekele, S Bellwied, R Bennett, S Berger, J Betts, W Bichsel, H Bieser, F Bland, L Blyth, C Bogdanov, A Bonner, BE Bossingham, R Boucham, A Bouvier, S Brady, FP Braithwaite, E Braithwaite, W Brown, RL Budilov, Y Byrd, C Caines, H Carlin, N Carroll, J Cebra, D Chen, ML Chen, W Chen, Y Chernenko, S Cherney, M Chikanian, A Chrin, JTM Christie, W Coffin, JP Conin, L Cormier, TM Cramer, J Crawford, HJ Das, A Deng, W Derevschikov, AA Didenko, L Dominik, W Draper, JE Dunin, V Dunlop, J Dyke, H Edwards, WR Eckardt, V Efremov, AV Emelianov, V Engelage, J Eppley, G Erazmus, B Etkin, A Fachini, P Faine, V Ferguson, MI Fessler, H Finch, E Fisyak, Y Flierl, D Foley, KJ Fritz, D Gagunashvili, N Germain, M Ghazikhanian, V Gilkes, M Giliberto, S Grabski, J Grachov, O Greiner, D Greiner, LC Grigoriev, V Gushin, E Gutbrod, H Hallman, TJ Hardtke, D Harris, JW Heffner, M Heppelmann, S Hirsch, A Hjort, E Hoffmann, GW Horsley, M Huang, H Humanic, T Huemmler, H Huyck, T Igo, GJ Ivanshin, YI Jacobs, P Jacobs, W Jacobson, S Jared, R Jones, P Judd, EG Jundt, F Kaplan, M Kaplin, V Keane, D Khodyrev, V Klay, J Klein, S Kolobashkin, L Konstantinov, A Kotchenda, L Kotov, I Kramer, M Kravtsov, P Kuhn, K Kunde, GJ Kutuev, R Lamont, M Lange, JS Lasiuk, B Laue, F Lebedev, A Lee, Z LeCompte, T Leonhardt, B Leontiev, V Leszczynski LeVine, MJ Li, Q Li, Z Liaw, CJ Lin, J Lindenbaum, SJ Liu, H Lisa, M Ljubicic, A Llope, W LoCurto, G Long, H Longacre, RS Love, WA Lutz, JR Lynn, D Madansky, L Majka, R Makarenko, TM Maliszewski, A Margetis, S Marks, K Martin, L Marx, J Matis, HS Matulenko, Y McShane, TS Meshanin, A Melnik, Y Michalon, A Miller, B Milosevich, Z Minaev, N Minor, RM Mitchell, J Moiseenko, VA Moltz, D Moore, CF Munhoz, MG Mutchler, GS Nelson, JM Nevski, P Nikitin, V Nilsen, B Nogach, L Nurushev, S Nystrand, J Odyniec, G Ogawa, A Ogilvie, CA Okorokov, V Olson, D Oltchak, A Ott, G Paic, G Pandey, S Panebratsev, Y Panitkin, SY Pavlinov, A Pawlak, T Peryt, W Perevoztchikov, V Petrov, VA Petukhov, Y Pinganaud, W Platner, E Pluta, J Porile, N Porter, J Poskanzer, AM Przewlocki, M Prindle, D Potrebenikova, E Pruneau, C Rai, G Ravel, O Ray, RL Razin, D Razin, S Reid, J Retiere, F Ridiger, A Riso, J Ritter, HG Roberts, JB Roehrich, D Rogachevskiy, O Rollefson, A Romero, JL Roy, C Runco, M Russ, DE Rykov, V Sakrejda, I Saltz, P Sandweiss, J Saulys, AC Savin, I Schambach, JJ Scharenberg, RP Schmitz, N Schroeder, LS Schuettauf, A Schulz, M Seger, J Seliverstov, D Seyboth, J Seyboth, P Shalnov, A Shestermanov, K Shi, Y Shvetsov, VS Silin, IN Smirnoff, N Snellings, R Soloviev, L Sowinski, J Spinka, HM Srivastava, B Stephenson, E Stock, R Strikhanov, M Stringfellow, B Stroebele, H Struck, C Sugarbaker, E Suire, C Sustich, A Symons, TJ Szanto, EM de Toledo, AS Takahashi, J Tang, A Thein, D Thomas, JH Tikhomirov, V Tikhonov, V Tonjes, MB Trainor, T Trentalange, S Tokarev, M Trofimov, V Tsai, O Tull, C Turner, K Ullrich, T Underwood, DG VanBuren, G VanderMolen, AM Vanyashin, A Vasiliev, A Vasilevski, LM Vigdor, S Voloshin, S Vu, CQ Wang, F Ward, HJ Weerasundra, D Wells, R Wells, R Wenaus, T Westfall, GD Whitfield, JP Whitten, C Wieman, H Willson, R Wissink, S Witt, R Wood, L Xu, N Xu, Z Yakutin, A Yamamoto, E Yang, J Yepes, P Yokosawa, A Yurevich, V Zhang, J Zhang, WM Zhidkov, N Zimmerman, D Zoulkarneev, R Zubarev, A AF Ackerman, KH Adams, N Adler, N Aluyshin, M Ananeva, MA Anderson, M Averichev, G Bacher, A Balewski, J Balrannikova, O Baudot, J Bekele, S Bellwied, R Bennett, S Berger, J Betts, W Bichsel, H Bieser, F Bland, L Blyth, C Bogdanov, A Bonner, BE Bossingham, R Boucham, A Bouvier, S Brady, FP Braithwaite, E Braithwaite, W Brown, RL Budilov, Y Byrd, C Caines, H Carlin, N Carroll, J Cebra, D Chen, ML Chen, W Chen, Y Chernenko, S Cherney, M Chikanian, A Chrin, JTM Christie, W Coffin, JP Conin, L Cormier, TM Cramer, J Crawford, HJ Das, A Deng, W Derevschikov, AA Didenko, L Dominik, W Draper, JE Dunin, V Dunlop, J Dyke, H Edwards, WR Eckardt, V Efremov, AV Emelianov, V Engelage, J Eppley, G Erazmus, B Etkin, A Fachini, P Faine, V Ferguson, MI Fessler, H Finch, E Fisyak, Y Flierl, D Foley, KJ Fritz, D Gagunashvili, N Germain, M Ghazikhanian, V Gilkes, M Giliberto, S Grabski, J Grachov, O Greiner, D Greiner, LC Grigoriev, V Gushin, E Gutbrod, H Hallman, TJ Hardtke, D Harris, JW Heffner, M Heppelmann, S Hirsch, A Hjort, E Hoffmann, GW Horsley, M Huang, H Humanic, T Huemmler, H Huyck, T Igo, GJ Ivanshin, YI Jacobs, P Jacobs, W Jacobson, S Jared, R Jones, P Judd, EG Jundt, F Kaplan, M Kaplin, V Keane, D Khodyrev, V Klay, J Klein, S Kolobashkin, L Konstantinov, A Kotchenda, L Kotov, I Kramer, M Kravtsov, P Kuhn, K Kunde, GJ Kutuev, R Lamont, M Lange, JS Lasiuk, B Laue, F Lebedev, A Lee, Z LeCompte, T Leonhardt, B Leontiev, V Leszczynski LeVine, MJ Li, Q Li, Z Liaw, CJ Lin, J Lindenbaum, SJ Liu, H Lisa, M Ljubicic, A Llope, W LoCurto, G Long, H Longacre, RS Love, WA Lutz, JR Lynn, D Madansky, L Majka, R Makarenko, TM Maliszewski, A Margetis, S Marks, K Martin, L Marx, J Matis, HS Matulenko, Y McShane, TS Meshanin, A Melnik, Y Michalon, A Miller, B Milosevich, Z Minaev, N Minor, RM Mitchell, J Moiseenko, VA Moltz, D Moore, CF Munhoz, MG Mutchler, GS Nelson, JM Nevski, P Nikitin, V Nilsen, B Nogach, L Nurushev, S Nystrand, J Odyniec, G Ogawa, A Ogilvie, CA Okorokov, V Olson, D Oltchak, A Ott, G Paic, G Pandey, S Panebratsev, Y Panitkin, SY Pavlinov, A Pawlak, T Peryt, W Perevoztchikov, V Petrov, VA Petukhov, Y Pinganaud, W Platner, E Pluta, J Porile, N Porter, J Poskanzer, AM Przewlocki, M Prindle, D Potrebenikova, E Pruneau, C Rai, G Ravel, O Ray, RL Razin, D Razin, S Reid, J Retiere, F Ridiger, A Riso, J Ritter, HG Roberts, JB Roehrich, D Rogachevskiy, O Rollefson, A Romero, JL Roy, C Runco, M Russ, DE Rykov, V Sakrejda, I Saltz, P Sandweiss, J Saulys, AC Savin, I Schambach, JJ Scharenberg, RP Schmitz, N Schroeder, LS Schuettauf, A Schulz, M Seger, J Seliverstov, D Seyboth, J Seyboth, P Shalnov, A Shestermanov, K Shi, Y Shvetsov, VS Silin, IN Smirnoff, N Snellings, R Soloviev, L Sowinski, J Spinka, HM Srivastava, B Stephenson, E Stock, R Strikhanov, M Stringfellow, B Stroebele, H Struck, C Sugarbaker, E Suire, C Sustich, A Symons, TJ Szanto, EM de Toledo, AS Takahashi, J Tang, A Thein, D Thomas, JH Tikhomirov, V Tikhonov, V Tonjes, MB Trainor, T Trentalange, S Tokarev, M Trofimov, V Tsai, O Tull, C Turner, K Ullrich, T Underwood, DG VanBuren, G VanderMolen, AM Vanyashin, A Vasiliev, A Vasilevski, LM Vigdor, S Voloshin, S Vu, CQ Wang, F Ward, HJ Weerasundra, D Wells, R Wells, R Wenaus, T Westfall, GD Whitfield, JP Whitten, C Wieman, H Willson, R Wissink, S Witt, R Wood, L Xu, N Xu, Z Yakutin, A Yamamoto, E Yang, J Yepes, P Yokosawa, A Yurevich, V Zhang, J Zhang, WM Zhidkov, N Zimmerman, D Zoulkarneev, R Zubarev, A TI The STAR Time Projection Chamber SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 14th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions CY MAY 10-15, 1999 CL TURIN, ITALY SP Ist Nazl Fica Nucleare, Univ Torino, Univ Piemonte Orientale, Regione Piemonte, Provincia Torino, Compagnia San Paolo, Cassa Risparmio Torino, Caen, Hamamatsu, Canberra, Tecnol Avanzate C1 Argonne Natl Lab, Argonne, IL 60439 USA. Univ Arkansas, Little Rock, AR 72204 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Birmingham, Birmingham B15 2TT, W Midlands, England. Univ Calif Berkeley, Berkeley, CA 94720 USA. Univ Calif Davis, Davis, CA USA. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Creighton Univ, Omaha, NE 68178 USA. Joint Inst Nucl Res Dubna, Lab High Energy, Dubna, Russia. Joint Inst Nucl Res Dubna, Particle Phys Lab, Dubna, Russia. Univ Frankfurt, D-6000 Frankfurt, Germany. Indiana Univ, Bloomington, IN 47405 USA. Johns Hopkins Univ, Baltimore, MD 21218 USA. Kent State Univ, Kent, OH USA. Lawrence Berkeley Lab, Berkeley, CA USA. MIT, Cambridge, MA 02139 USA. Max Planck Inst Phys, D-80805 Munich, Germany. Michigan State Univ, E Lansing, MI 48824 USA. Moscow Phys Engn Inst, Moscow, Russia. CUNY City Coll, New York, NY 10031 USA. Ohio State Univ, Columbus, OH 43210 USA. Penn State Univ, University Pk, PA 16802 USA. Inst High Energy Phys, Protvino, Russia. Purdue Univ, W Lafayette, IN 47907 USA. Rice Univ, Houston, TX 77251 USA. Univ Sao Paulo, BR-05508 Sao Paulo, Brazil. SUBATECH, Nantes, France. Univ Texas, Austin, TX 78712 USA. Warsaw Univ, Warsaw, Poland. Warsaw Univ Technol, PL-00661 Warsaw, Poland. Univ Washington, Seattle, WA 98195 USA. Wayne State Univ, Detroit, MI 48202 USA. Yale Univ, New Haven, CT 06520 USA. RP Ackerman, KH (reprint author), Argonne Natl Lab, Argonne, IL 60439 USA. RI Takahashi, Jun/B-2946-2012; Carlin Filho, Nelson/C-2187-2012; Chen, Yu/E-3788-2012; Witt, Richard/H-3560-2012; Vanyashin, Aleksandr/H-7796-2013; Voloshin, Sergei/I-4122-2013; Strikhanov, Mikhail/P-7393-2014; Tikhomirov, Vladimir/M-6194-2015 OI Takahashi, Jun/0000-0002-4091-1779; Vanyashin, Aleksandr/0000-0002-0367-5666; Strikhanov, Mikhail/0000-0003-2586-0405; Tikhomirov, Vladimir/0000-0002-9634-0581 NR 0 TC 51 Z9 51 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 27 PY 1999 VL 661 BP 681C EP 685C DI 10.1016/S0375-9474(99)00549-7 PG 5 WC Physics, Nuclear SC Physics GA 277XJ UT WOS:000084958600116 ER PT J AU Armstrong, TA Barish, KN Batsouli, S Bennett, SJ Chikanian, A Coe, SD Cormier, TM Davies, R Dover, CB Fachini, P Fadem, B Finch, LE George, NK Greene, SV Haridas, P Hill, JC Hirsch, AS Hoversten, R Huang, HZ Jaradat, H Kumar, BS Lainis, T Lajoie, JG Lewis, RA Li, Q Libby, B Majka, RD Miller, TE Munhoz, MG Nagle, JL Pless, IA Pope, JK Porile, NT Pruneau, CA Rabin, MSZ Reid, JD Rimai, A Rose, A Rotondo, FS Sandweiss, J Scharenberg, RP Slaughter, AJ Smith, GA Tincknell, ML Toothacker, WS Van Buren, G Wohn, FK Xu, Z AF Armstrong, TA Barish, KN Batsouli, S Bennett, SJ Chikanian, A Coe, SD Cormier, TM Davies, R Dover, CB Fachini, P Fadem, B Finch, LE George, NK Greene, SV Haridas, P Hill, JC Hirsch, AS Hoversten, R Huang, HZ Jaradat, H Kumar, BS Lainis, T Lajoie, JG Lewis, RA Li, Q Libby, B Majka, RD Miller, TE Munhoz, MG Nagle, JL Pless, IA Pope, JK Porile, NT Pruneau, CA Rabin, MSZ Reid, JD Rimai, A Rose, A Rotondo, FS Sandweiss, J Scharenberg, RP Slaughter, AJ Smith, GA Tincknell, ML Toothacker, WS Van Buren, G Wohn, FK Xu, Z CA E864 Collaboration TI Mass dependence of light-nucleus production in ultrarelativistic heavy-ion collisions SO PHYSICAL REVIEW LETTERS LA English DT Article ID SEARCH; MATTER; AGS AB Light nuclei can be produced in the central reaction zone via coalescence in relativistic heavy-ion collisions. Experiment 864 at BNL has measured the production of ten light nuclei with nuclear number A = 1 to A = 7 at rapidity y similar or equal to 1.9 and p(T)/A similar or equal to 300 MeV/c. Data were taken with a Au beam of momentum of 11.5A GeV/c on a Pb or Pt target with different experimental settings. The invariant yields show a striking exponential dependence on nuclear number with a penalty factor of about 50 per additional nucleon. Detailed analysis reveals that the production may depend on the spin factor of the nucleus and the nuclear binding energy as well. C1 Penn State Univ, University Pk, PA 16802 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Calif Los Angeles, Los Angeles, CA 90095 USA. Univ Calif Riverside, Riverside, CA 92521 USA. Columbia Univ, Nevis Lab, Irvington, NY 10533 USA. Iowa State Univ, Ames, IA 50011 USA. Univ Massachusetts, Amherst, MA 01003 USA. MIT, Cambridge, MA 02139 USA. Purdue Univ, W Lafayette, IN 47907 USA. US Mil Acad, W Point, NY 10996 USA. Vanderbilt Univ, Nashville, TN 37235 USA. Wayne State Univ, Detroit, MI 48201 USA. Yale Univ, New Haven, CT 06520 USA. RP Armstrong, TA (reprint author), Vanderbilt Univ, 221 Kirkland Hall, Nashville, TN 37235 USA. NR 26 TC 20 Z9 20 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 DEC 27 PY 1999 VL 83 IS 26 BP 5431 EP 5434 DI 10.1103/PhysRevLett.83.5431 PG 4 WC Physics, Multidisciplinary SC Physics GA 268GQ UT WOS:000084406300007 ER PT J AU Jeon, S Koch, V AF Jeon, S Koch, V TI Fluctuations of particle ratios and the abundance of hadronic resonances SO PHYSICAL REVIEW LETTERS LA English DT Article ID COLLISIONS AB We argue that the event-by-event fluctuations of the ratio-of positively charged over negatively charged pions provides a measurement of the number of rho and omega mesons right after hadronization. This finding can be utilized to put the hypothesis,of chemical equilibration in relativistic heavy ion collisions to a test. The fluctuation may also serve as an indicator for new physics to be discovered in relativistic heavy-ion collisions. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Jeon, S (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 15 TC 126 Z9 130 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 DEC 27 PY 1999 VL 83 IS 26 BP 5435 EP 5438 DI 10.1103/PhysRevLett.83.5435 PG 4 WC Physics, Multidisciplinary SC Physics GA 268GQ UT WOS:000084406300008 ER PT J AU Lerma, F Devlin, M LaFosse, DR Sarantites, DG Wyss, R Baktash, C Clark, RM Lee, IY Macchiavelli, AO MacLeod, RW Soltysik, D Tabor, SL AF Lerma, F Devlin, M LaFosse, DR Sarantites, DG Wyss, R Baktash, C Clark, RM Lee, IY Macchiavelli, AO MacLeod, RW Soltysik, D Tabor, SL TI Accurate lifetime measurements of superdeformed bands in A similar to 80 nuclei SO PHYSICAL REVIEW LETTERS LA English DT Article ID REGION; SR-82 AB Comparative measurements of the lifetimes of yrast superdeformed (SD) states in Sr80-83, Y-83, and Zr-84 have been performed using the Doppler-shift attenuation method. Thus, the transition quadrupole moments (Q(t)) of these structures have been determined accurately. The yrast SD bands in Sr80-83 possess Q(t) similar to 3.5 e b, while the Y-83 and Zr-84 Cases display Q(t) = 4.4 e b and 5.6 e b, respectively. Intruder orbital assignments based on these results demonstrate a previously unnoticed transition in the structure of the SD bands when the proton number changes from Z = 38 to Z greater than or equal to 39. C1 Washington Univ, Dept Chem, St Louis, MO 63130 USA. KTH, Dept Phys Frescati, S-10405 Stockholm, Sweden. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37830 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. RP Lerma, F (reprint author), Washington Univ, Dept Chem, St Louis, MO 63130 USA. RI Devlin, Matthew/B-5089-2013 OI Devlin, Matthew/0000-0002-6948-2154 NR 21 TC 24 Z9 24 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 DEC 27 PY 1999 VL 83 IS 26 BP 5447 EP 5450 DI 10.1103/PhysRevLett.83.5447 PG 4 WC Physics, Multidisciplinary SC Physics GA 268GQ UT WOS:000084406300011 ER PT J AU Varga, K AF Varga, K TI Multipositronic systems SO PHYSICAL REVIEW LETTERS LA English DT Article ID QUANTUM MONTE-CARLO; POSITRONIUM HYDRIDE; GROUND-STATE; BIEXCITONS; COMPLEXES; STABILITY; LITHIUM; ATOMS AB The stability and structure of systems comprising a negative ion and positrons are investigated by the stochastic variational method. It is shown that the H- and the Li- ions can bind not only one but two positrons. The binding energies of these double positronic atoms, E(H-, e(+), e(+)) = 0.57 eV, and E(Li-, e(+) , e(+)) 0.15 eV are somewhat smaller than those of their single positronic counterparts [E(-HPs) = 1.06 eV and E(LiPs) =0.32 eV]. We have also-found that two Ps(-)'s can form a bound system with a proton. C1 Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. RP Varga, K (reprint author), Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. RI Varga, Kalman/A-7102-2013 NR 25 TC 24 Z9 24 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 DEC 27 PY 1999 VL 83 IS 26 BP 5471 EP 5474 DI 10.1103/PhysRevLett.83.5471 PG 4 WC Physics, Multidisciplinary SC Physics GA 268GQ UT WOS:000084406300017 ER PT J AU Cherfils, C Glendinning, SG Galmiche, D Remington, BA Richard, AL Haan, S Wallace, R Dague, N Kalantar, DH AF Cherfils, C Glendinning, SG Galmiche, D Remington, BA Richard, AL Haan, S Wallace, R Dague, N Kalantar, DH TI Convergent Rayleigh-Taylor experiments on the Nova laser SO PHYSICAL REVIEW LETTERS LA English DT Article ID INSTABILITY GROWTH-RATES; HYDRODYNAMIC INSTABILITY; PLANAR TARGETS; DRIVEN; FEEDTHROUGH; IMPLOSIONS; CAMERAS AB Experiments have been done on the Nova laser to investigate the effects of convergence on Rayleigh-Taylor growth. We ablatively accelerated planar CH(Br) foils or hemispherical CH(Ge) capsules with identical initial perturbations. Experimental results showed: the decrease of the effective wavelength of results. the perturbation and the early onset of nonlinearity in the converging case compared to the planar case. Numerical simulations using the 2D Lagrangian code FCI2 are m good agreement with the experimental results. C1 CEA, DAM Ile France, F-91680 Bruyeres Le Chatel, France. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Cherfils, C (reprint author), CEA, DAM Ile France, BP 12, F-91680 Bruyeres Le Chatel, France. NR 28 TC 37 Z9 39 U1 2 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 DEC 27 PY 1999 VL 83 IS 26 BP 5507 EP 5510 DI 10.1103/PhysRevLett.83.5507 PG 4 WC Physics, Multidisciplinary SC Physics GA 268GQ UT WOS:000084406300026 ER PT J AU Sanford, TWL Olson, RE Bowers, RL Chandler, GA Derzon, MS Hebron, DE Leeper, RJ Mock, RC Nash, TJ Peterson, DL Ruggles, LE Simpson, WW Struve, KW Vesey, RA AF Sanford, TWL Olson, RE Bowers, RL Chandler, GA Derzon, MS Hebron, DE Leeper, RJ Mock, RC Nash, TJ Peterson, DL Ruggles, LE Simpson, WW Struve, KW Vesey, RA TI Z pinch-generated x rays demonstrate potential for indirect-drive ICF experiments SO PHYSICAL REVIEW LETTERS LA English DT Article ID NATIONAL-IGNITION-FACILITY; POWER; DESIGN AB Hohlraums measuring 6 mm in diameter by 7 mm height have been heated by x rays from a Z pinch. Over the measured x-ray input powers P of 0.7 to lj TW, the hohlraum radiation temperature T increases from similar to 55 to similar to 130 eV, and is in agreement with the Planckian relation T similar to P-1/4. The results suggest that indirect-drive inertial-confinement-fusion experiments involving National Ignition Facility relevant pulse shapes and <2 mm diameter capsules can be studied using this arrangement. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Sanford, TWL (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 18 TC 76 Z9 83 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 DEC 27 PY 1999 VL 83 IS 26 BP 5511 EP 5514 DI 10.1103/PhysRevLett.83.5511 PG 4 WC Physics, Multidisciplinary SC Physics GA 268GQ UT WOS:000084406300027 ER PT J AU Yoo, CS Cynn, H Gygi, F Galli, G Iota, V Nicol, M Carlson, S Hausermann, D Mailhiot, C AF Yoo, CS Cynn, H Gygi, F Galli, G Iota, V Nicol, M Carlson, S Hausermann, D Mailhiot, C TI Crystal structure of carbon dioxide at high pressure: "Superhard" polymeric carbon dioxide SO PHYSICAL REVIEW LETTERS LA English DT Article ID PHASE-TRANSITIONS; SOLID CO2; TRIDYMITE; TEMPERATURE AB The crystal structures of two molecular phases (I and III) and a polymeric phase (V) of CO2 have been investigated to 60 GPa. CO2-I (Pa3) transforms to CO2-III (Cmca) at 12 GPa with almost no I:change of density. Although CO2-III persists in Cmca to at least 60 GPa at ambient temperature, it transforms when heated to 1800 K above 49 GPa to-tridymite, (P2(1)2(1)2(1)) CO2-V with 15.3% volume change. Each carbon atom of CO2-V is tetrahedrally bonded to four oxygen atoms. CO2-V is likely superhard with low compressibility B-0 = 365 GPa, similar to cubic BN. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Univ Nevada, High Pressure Sci Ctr, Las Vegas, NV 89154 USA. European Synchrotron Radiat Facil, F-38043 Grenoble, France. RP Yoo, CS (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NR 22 TC 160 Z9 163 U1 4 U2 26 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 DEC 27 PY 1999 VL 83 IS 26 BP 5527 EP 5530 DI 10.1103/PhysRevLett.83.5527 PG 4 WC Physics, Multidisciplinary SC Physics GA 268GQ UT WOS:000084406300031 ER PT J AU von Laszewski, G AF von Laszewski, G TI A loosely coupled metacomputer: co-operating job submissions across multiple supercomputing sites SO CONCURRENCY-PRACTICE AND EXPERIENCE LA English DT Article AB This paper introduces a general metacomputing framework for submitting jobs across a variety of distributed computational resources, A first-come, first-served scheduling algorithm distributes the jobs across the computer resources, Because dependencies between jobs are expressed via a dataflow graph, the framework is more than just a uniform interface to the independently running queuing systems and interactive shells on each computer system. Using the dataflow approach extends the concept of sequential batch and interactive processing to running programs across multiple computers and computing sites in co-operation, We present results from a Grand Challenge case study showing that the turnaround time was dramatically reduced by having access to several supercomputers at runtime. The framework is applicable to other complex scientific problems that are coarse grained, Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. RP von Laszewski, G (reprint author), Argonne Natl Lab, Div Math & Comp Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI von Laszewski, Gregor/C-2808-2012 OI von Laszewski, Gregor/0000-0001-9558-179X NR 17 TC 7 Z9 7 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 1040-3108 J9 CONCURRENCY-PRACT EX JI Concurrency-Pract. Exp. PD DEC 25 PY 1999 VL 11 IS 15 BP 933 EP 948 DI 10.1002/(SICI)1096-9128(19991225)11:15<933::AID-CPE461>3.0.CO;2-J PG 16 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA 307BF UT WOS:000086633000004 ER PT J AU Heinze, S Nie X Blugel, S Weinert, M AF Heinze, S Nie, X Blugel, S Weinert, M TI Electric-field-induced changes in scanning tunneling microscopy images of metal surfaces SO CHEMICAL PHYSICS LETTERS LA English DT Article ID SPECTROSCOPY; STATES AB Electric-field-dependent changes of scanning tunneling microscopy (STM) images of metal surfaces, metallic surface alloys, and ultra-thin magnetic films are predicted. We present a two-state model that demonstrates the general conditions leading to an inversion of the corrugation pattern as a function of field strength, and relate the effects to field-induced changes of the potential barrier. This image reversal for a pure metal surface corresponds to a change from a normal to an anticorrugated STM image. For ordered surface alloys, a switch of the imaged chemical species is possible and may even cause a change from a p(1 X 1) to a c(2 X 2) image at different fields. We explicitly demonstrate the effects by first-principles calculations of the Fe(001) surface. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Forschungszentrum Julich, Inst Festkorperforsch, D-52425 Julich, Germany. Univ Hamburg, Zentrum Mikrostrukturforsch, D-20355 Hamburg, Germany. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Blugel, S (reprint author), Forschungszentrum Julich, Inst Festkorperforsch, Postfach 1913, D-52425 Julich, Germany. RI Blugel, Stefan/J-8323-2013 OI Blugel, Stefan/0000-0001-9987-4733 NR 14 TC 19 Z9 19 U1 0 U2 5 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 DEC 24 PY 1999 VL 315 IS 3-4 BP 167 EP 172 DI 10.1016/S0009-2614(99)01210-5 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 269TF UT WOS:000084493100003 ER PT J AU Wang, HL McBranch, DW Klimov, VI Helgeson, R Wudl, F AF Wang, HL McBranch, DW Klimov, VI Helgeson, R Wudl, F TI Controlled unidirectional energy transfer in luminescent self-assembled conjugated polymer superlattices SO CHEMICAL PHYSICS LETTERS LA English DT Article ID FILMS AB We report the synthesis and characterization of multi-layered organic superlattices made by polyelectrolyte self-assembly. Self-assembled films were formed from a water-soluble form of poly(phenylene vinylene) with high-photoluminescence quantum efficiency (QE). We observed a self-quenching of the luminescence with increasing film thickness. This quenching can be reversed by inserting spacer layers between each active conjugated layer. A red shift of the luminescence was also observed as additional poly(phenylene vinylene) layers were added. We attribute the red shift and increasing QE to changing polymer conformation, together with efficient unidirectional energy transfer. We rule out quantum confinement as the origin of the red shift. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Univ Calif Los Angeles, Exot Mat Inst, Dept Chem & Biochem, Los Angeles, CA 90095 USA. RP McBranch, DW (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, MS J567, Los Alamos, NM 87545 USA. NR 13 TC 37 Z9 39 U1 0 U2 7 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 DEC 24 PY 1999 VL 315 IS 3-4 BP 173 EP 180 DI 10.1016/S0009-2614(99)01176-8 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 269TF UT WOS:000084493100004 ER PT J AU Fohlisch, A Hasselstrom, J Karis, O Vaterlein, P Martensson, N Nilsson, A Heske, C Stichler, M Keller, C Wurth, W Menzel, D AF Fohlisch, A Hasselstrom, J Karis, O Vaterlein, P Martensson, N Nilsson, A Heske, C Stichler, M Keller, C Wurth, W Menzel, D TI Franck-Condon breakdown in core-level photoelectron spectroscopy of chemisorbed CO SO CHEMICAL PHYSICS LETTERS LA English DT Article ID VIBRATIONALLY RESOLVED PHOTOELECTRON; MOLECULAR PHOTO-IONIZATION; ANGULAR-DISTRIBUTIONS; SHAPE RESONANCES; THRESHOLD REGION; EXCITED-STATES; PHOTOIONIZATION; PHOTOEMISSION; SPECTRA; CHANNEL AB The photon energy dependence of the vibrational fine structure in the Cls and Ols X-ray photoelectron main lines of chemisorbed CO on Ni(100) and Ru(0001) has been measured from 6 to 150 eV above the core-level thresholds. Significant deviations from the behavior in gas-phase CO are found. A strong dominance of the adiabatic peak towards threshold is found for the Cls, but not the Ols, lines. In the Cls lines, we observe a broad maximum of vibrational excitation 5 eV above the shape resonance. At high photon energies, Franck-Condon behavior is observed in both the Cls and Ols lines. This behavior is discussed in terms of the adsorbate electronic structure and the dynamic metallic screening upon core ionization. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Uppsala, Dept Phys, S-75121 Uppsala, Sweden. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Tech Univ Munich, Phys Dept E20, D-85747 Garching, Germany. RP Fohlisch, A (reprint author), Univ Uppsala, Dept Phys, Box 530, S-75121 Uppsala, Sweden. RI Nilsson, Anders/E-1943-2011; OI Nilsson, Anders/0000-0003-1968-8696; Menzel, Dietrich/0000-0002-7188-8532; Alexander, Fohlisch/0000-0003-4126-8233 NR 25 TC 17 Z9 17 U1 0 U2 8 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 DEC 24 PY 1999 VL 315 IS 3-4 BP 194 EP 200 DI 10.1016/S0009-2614(99)01194-X PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 269TF UT WOS:000084493100007 ER PT J AU Christoffel, KM Kim, K Skokov, S Bowman, JM Gray, SK AF Christoffel, KM Kim, K Skokov, S Bowman, JM Gray, SK TI Quantum and quasiclassical reactive scattering of O(D-1)+HCl using an ab initio potential SO CHEMICAL PHYSICS LETTERS LA English DT Article ID UNIMOLECULAR DISSOCIATION; RATE CONSTANTS; HCL; HOCL; O(1D2)+HCL->OH+CL; DYNAMICS; SURFACE; O(1D2); STATE AB We report quasiclassical trajectory and quantum wavepacket calculations for the reaction of O(D-1) + HCl using a recent ab initio potential energy surface. The quantum calculations, done only for zero total angular momentum and HCl (v = j = 0), agree well with corresponding trajectory results in terms of total reactivity and the ClO/OH branching ratio. Quasiclassical trajectory cross-sections to final vibrational states of the OH and ClO products, the ClO/OH branching ratio, and the CIO translational energy distribution at one collision energy are also reported. The latter two quantities are compared with results of recent molecular beam experiments. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Emory Univ, Dept Chem, Atlanta, GA 30322 USA. Emory Univ, Cherry L Emerson Ctr Sci Computat, Atlanta, GA 30322 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Bowman, JM (reprint author), Emory Univ, Dept Chem, 1515 Pierce Dr, Atlanta, GA 30322 USA. NR 25 TC 36 Z9 36 U1 0 U2 0 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 DEC 24 PY 1999 VL 315 IS 3-4 BP 275 EP 281 DI 10.1016/S0009-2614(99)01185-9 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 269TF UT WOS:000084493100017 ER PT J AU Thanos, CD Faham, S Goodwill, KE Cascio, D Phillips, M Bowie, JU AF Thanos, CD Faham, S Goodwill, KE Cascio, D Phillips, M Bowie, JU TI Monomeric structure of the human EphB2 sterile alpha motif domain SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID RECEPTOR TYROSINE KINASE; PROTEIN-KINASE; IN-VITRO; LIGAND; BINDING; SAM; EXPRESSION; GUIDANCE; SYSTEM; ELF-1 AB The sterile a motif (SAM) domain is a protein module found in many diverse signaling proteins. SAM domains in some systems have been shown to self-associate. Previous crystal structures of an EphA4-SAM domain dimer (Stapleton, D,, Balan, I., Pawson, T,, and Sicheri, F, (1999) Not, Struct. Biol. 6, 44-49) and a possible EphB2-SAM oligomer (Thanos, C, D,, Goodwill, K, E,, and Bowie, J, U, (1999) Science 283, 833-836) both revealed large interfaces comprising an exchange of N-terminal peptide arms. Within the arm, a conserved hydrophobic residue (Tyr-8 in the EphB2-SAM structure or Phe-910 in the EphA4-SAM structure) is anchored into a hydrophobic cleft on a neighboring molecule. Here we have solved a new crystal form of the human EphB2-SAM domain that has the same overall SARI domain fold yet has no substantial intermolecular contacts. In the new structure, the N-terminal peptide arm of the EphB2-SAM domain protrudes out from the core of the molecule, leaving both the arm (including Tyr-8) and the hydrophobic cleft solvent-exposed, To verify that Tyr-8 is solvent-exposed in solution, we made a Tyr-8 to Ala-8 mutation and found that the EphB2-SAM domain structure and stability were only slightly altered. These results suggest that Tyr-8 is not part of the hydrophobic core of the EphB2-SAM domain and is conserved for functional reasons. Cystallographic evidence suggests a possible role for the N-terminal arm in oligomerization, In the absence of a direct demonstration of biological relevance, however, the functional role of the N-terminal arm remains an open question. C1 Univ Calif Los Angeles, DOE Lab Struct Biol & Mol Med, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Chem & Biochem, Los Angeles, CA 90095 USA. RP Bowie, JU (reprint author), Univ Calif Los Angeles, DOE Lab Struct Biol & Mol Med, Los Angeles, CA 90095 USA. NR 41 TC 33 Z9 34 U1 0 U2 2 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD DEC 24 PY 1999 VL 274 IS 52 BP 37301 EP 37306 DI 10.1074/jbc.274.52.37301 PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 267WR UT WOS:000084382700067 PM 10601296 ER PT J AU Rescigno, TN Baertschy, M Isaacs, WA McCurdy, CW AF Rescigno, TN Baertschy, M Isaacs, WA McCurdy, CW TI Collisional breakup in a quantum system of three charged particles SO SCIENCE LA English DT Article ID DIFFERENTIAL CROSS-SECTIONS; ELECTRON-IMPACT IONIZATION; HYDROGEN SCATTERING; FORM AB Since the invention of quantum mechanics, even the simplest example of the collisional breakup of a system of charged particles, e(-) + H --> H+ + e(-) + e(-) (where e(-) is an electron and H is hydrogen), has resisted solution and is now one of the Last unsolved fundamental problems in atomic physics. A complete solution requires calculation of the energies and directions for a final state in which all three particles are moving away from each other. Even with supercomputers, the correct mathematical description of this state has proved difficult to apply, A framework for solving ionization problems in many areas of chemistry and physics is finally provided by a mathematical transformation of the Schrodinger equation that makes the final state tractable, providing the key to a numerical solution of this problem that reveals its full dynamics. C1 Lawrence Livermore Natl Lab, Phys Directorate, Livermore, CA 94551 USA. Lawrence Livermore Natl Lab, Dept Appl Sci, Livermore, CA 94550 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Rescigno, TN (reprint author), Lawrence Livermore Natl Lab, Phys Directorate, POB 5508, Livermore, CA 94551 USA. NR 26 TC 366 Z9 373 U1 2 U2 11 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 EI 1095-9203 J9 SCIENCE JI Science PD DEC 24 PY 1999 VL 286 IS 5449 BP 2474 EP 2479 DI 10.1126/science.286.5449.2474 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 268RQ UT WOS:000084429700038 ER PT J AU Wu, K Iedema, MJ Cowin, JP AF Wu, K Iedema, MJ Cowin, JP TI Ion penetration of the water-oil interface SO SCIENCE LA English DT Article ID DYNAMICS AB Ions typically pass with difficulty from water into organic phases because of water's superior solvation power. This inhibits such processes as ion transport in batteries or in Lipid bilayers of cells. ion penetration across such an interface was studied with unusual structural control. Hydronium ions were soft-landed at 1 electron volt on cold films of 3-methylpentane ("oil") on a metal substrate. The field produced by these ions drove them through the films when warmed. Coadsorption of water (0.14 to 35 bilayers) inhibited the ion penetration by creating a solvation energy trap. A Born solvation model successfully predicted the trapping energies (0 to 38 kilojoules per mole). C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Cowin, JP (reprint author), Pacific NW Natl Lab, Box 999,Mail Stop K8-88, Richland, WA 99352 USA. RI Wu, Kai/A-4903-2011 OI Wu, Kai/0000-0002-5016-0251 NR 20 TC 24 Z9 25 U1 2 U2 15 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 DEC 24 PY 1999 VL 286 IS 5449 BP 2482 EP 2485 DI 10.1126/science.286.5449.2482 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 268RQ UT WOS:000084429700040 ER PT J AU Matskevich, NI McCallum, RW AF Matskevich, NI McCallum, RW TI The 1 : 2 : 3-phases in the Y(Ho, Gd, Nd)-Ba-Cu-O: calorimetric investigations, correlations between thermodynamic and structural properties SO THERMOCHIMICA ACTA LA English DT Article DE calorimetry; Re-Ba-Cu-O system; stability; thermodynamics ID SYSTEM AB On the basis of dissolution enthalpies of Y2O3, Gd2O3, Nd2O3, Ho2O3, CUO, BaCO3, YBa2Cu3O6.9, HoBa2Cu3O6.9, GdBa2Cu3O6.9, NdBa2Cu3O6.98 measured by solution calorimetry in 6 N HCl at 323.15 K the following values were determined. (1) enthalpies of formation of Rel 2 3 phases from binary oxides: Delta(ox)H(o)(Y123, 323.15 K) = - 127.5 +/- 4.6 kJ mol(-1); Delta(ox)H(o)(Ho123, 323.15K) = -131.4 +/- 8.6 kJ mol(-1); Delta(ox)H(o)(Gd123, 323.15K) = -180.0 +/- 7.3 kJ mol(-1) Delta(ox)H(o)(Nd123, 323.15 K) = -165.0 +/- 8.8 kJ mol(-1); (2) enthalpies of formation of Rel 2 3 phases from mixtures of Re2O3, BaCO3, CuO; (3)enthalpies of formation of Rel 2 3 phases from mixtures of Re2O3, BaCuO2, CuO; (4) standard formation enthalpies of Rel 2 3 phases Delta(f)H(o)(Y123, 323.15K) = -2643.5 +/- 9.6 kJ mol(-1); Delta(f)H(o)(Ho123, 323.15 K) = -2635.3 +/- 12.2 kJ mol(-1); Delta(f)H(o)(Gd123, 323.15 K) = -2663.4 +/- 11.0 kJ mol(-1); Delta(f)H(o)(Y123, 323.15 K) = -2632.6 +/- 12.0 kJ mol(-1). The correlations between thermodynamic data and structural parameters of Rel 2 3 phases were established. It had been noted that the stability increase was correlated with the relative difference decrease of lattice parameters of Re2O3 and BaO layers from 4.65% for BaO-Ho2O3 to 4.37% for BaO-Y2O3, 3.86% for BaO-Nd2O3, 2.42% for BaO-Gd2O3. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Russian Acad Sci, Inst Organ Chem, Siberian Branch, Novosibirsk 630090, Russia. Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. RP Matskevich, NI (reprint author), Russian Acad Sci, Inst Organ Chem, Siberian Branch, Novosibirsk 630090, Russia. NR 9 TC 11 Z9 11 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0040-6031 J9 THERMOCHIM ACTA JI Thermochim. Acta PD DEC 24 PY 1999 VL 342 IS 1-2 BP 41 EP 46 DI 10.1016/S0040-6031(99)00314-7 PG 6 WC Thermodynamics; Chemistry, Analytical; Chemistry, Physical SC Thermodynamics; Chemistry GA 266PE UT WOS:000084307700005 ER PT J AU Overbury, SH Mullins, DR Huntley, DR Kundakovic, L AF Overbury, SH Mullins, DR Huntley, DR Kundakovic, L TI Chemisorption and reaction of sulfur dioxide with oxidized and reduced ceria surfaces SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID SO2; ADSORPTION; OXIDES; TIO2(110) AB The interaction of SO2 with highly oriented ceria films is studied as a function of coverage, temperature, and degree of oxidation of the ceria. Soft X-ray photoemission (SXPS) is used to analyze the oxidation state of the ceria and the evolution of the SO2-derived species, while thermal desorption spectroscopy is used to analyze the desorption products. The principle interaction is chemisorption of SO2 at oxygen anions, which reversibly desorbs as SO2 over a broad temperature range from 200 to 600 K. This interaction is characterized as a Lewis acid-base interaction and occurs with approximately equal facility if the surface is hydroxylated or sulfided. On reduced ceria the adsorption is more heterogeneous, suggesting a variety of local bending environments, including a small, distinguishable amount of adsorption at Ce3+ sites. A significant portion of the chemisorbed SO2 converts to sulfide above 300 K, and the resulting sulfide then equilibrates between bulk and surface sites above 600 K. Adsorption at a sulfide site leads to a 1.5 eV shift in the sulfide S 2p state toward higher binding energy. Thermal conversion of chemisorbed SO2 to sulfate is not observed. The results are compared with previous studies of NO adsorption on ceria films and with similar studies of SO2 chemisorption on titania. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Overbury, SH (reprint author), Oak Ridge Natl Lab, POB 2008,Bldg 4500 N,MS 6201, Oak Ridge, TN 37831 USA. RI Overbury, Steven/C-5108-2016 OI Overbury, Steven/0000-0002-5137-3961 NR 25 TC 50 Z9 50 U1 1 U2 12 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 DEC 23 PY 1999 VL 103 IS 51 BP 11308 EP 11317 DI 10.1021/jp992240a PG 10 WC Chemistry, Physical SC Chemistry GA 271NY UT WOS:000084601400012 ER PT J AU Kern, D Volkman, BF Luginbuhl, P Nohaile, MJ Kustu, S Wemmer, DE AF Kern, D Volkman, BF Luginbuhl, P Nohaile, MJ Kustu, S Wemmer, DE TI Structure of a transiently phosphorylated switch in bacterial signal transduction SO NATURE LA English DT Article ID RESPONSE REGULATOR; 3-DIMENSIONAL STRUCTURE; RECEIVER DOMAIN; NMR STRUCTURE; PROTEIN CHEY; CHEMOTAXIS; ACTIVATION; CONFORMATION; MECHANISM; DYNAMICS AB Receiver domains are the dominant molecular switches in bacterial signalling(1,2), Although several structures of non-phosphorylated receiver domains have been reported(3-8), a detailed structural understanding of the activation arising from phosphorylation has been impeded by the very short half-lives of the aspartyl-phosphate linkages. Here we present the first structure of a receiver domain in its active state, the phosphorylated receiver domain of the bacterial enhancer-binding protein NtrC (nitrogen regulatory protein C), Nuclear magnetic resonance spectra were taken during steady-state autophosphorylation/dephosphorylation, and three-dimensional spectra from multiple samples were combined. Phosphorylation induces a large conformational change involving a displacement of beta-strands 4 and 5 and alpha-helices 3 and 4 away from the active site, a register shift and an axial rotation in helix 4, This creates an exposed hydrophobic surface that is likely to transmit the signal to the transcriptional activation domain. C1 Brandeis Univ, Dept Biochem, Waltham, MA 02454 USA. Univ Wisconsin, Dept Biochem, Natl Magnet Resonance Facil, Madison, WI 53706 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Plant & Microbial Sci, Berkeley, CA 94720 USA. RP Kern, D (reprint author), Brandeis Univ, Dept Biochem, Waltham, MA 02454 USA. NR 29 TC 159 Z9 162 U1 1 U2 10 PU MACMILLAN PUBLISHERS LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD DEC 23 PY 1999 VL 402 IS 6764 BP 894 EP 898 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 269ML UT WOS:000084482000037 PM 10622255 ER PT J AU Bearden, I Boggild, H Boissevain, J Conin, L Dodd, J Erazmus, B Esumi, S Fabjan, CW Ferenc, D Fields, DE Franz, A Gaardhoje, JJ Hansen, AG Hansen, O Hardtke, D van Hecke, H Holzer, EB Humanic, TJ Hummel, P Jacak, BV Jayanti, R Kaimi, K Kaneta, M Kohama, T Kopytine, ML Leltchouk, M Ljubicic, A Lorstad, B Maeda, N Martin, L Medvedev, A Murray, M Ohnishi, H Paic, G Pandey, SU Piuz, F Pluta, J Polychronakos, V Potekhin, M Poulard, G Reichhold, D Sakaguchi, A Schmidt-Sorensen, J Simon-Gillo, J Sondheim, W Sugitate, T Sullivan, JP Sumi, Y Willis, WJ Wolf, KL Xu, N Zachary, DS AF Bearden, I Boggild, H Boissevain, J Conin, L Dodd, J Erazmus, B Esumi, S Fabjan, CW Ferenc, D Fields, DE Franz, A Gaardhoje, JJ Hansen, AG Hansen, O Hardtke, D van Hecke, H Holzer, EB Humanic, TJ Hummel, P Jacak, BV Jayanti, R Kaimi, K Kaneta, M Kohama, T Kopytine, ML Leltchouk, M Ljubicic, A Lorstad, B Maeda, N Martin, L Medvedev, A Murray, M Ohnishi, H Paic, G Pandey, SU Piuz, F Pluta, J Polychronakos, V Potekhin, M Poulard, G Reichhold, D Sakaguchi, A Schmidt-Sorensen, J Simon-Gillo, J Sondheim, W Sugitate, T Sullivan, JP Sumi, Y Willis, WJ Wolf, KL Xu, N Zachary, DS CA NA44 Collaboration TI Strange meson enhancement in PbPb collisions SO PHYSICS LETTERS B LA English DT Article DE relativistic heavy ion collisions; particle production; kaon; pion; strangeness enhancement; quark-gluon plasma ID SPECTRA; MATTER AB The NA44 Collaboration has measured yields and differential distributions of K+, K-, pi(+), pi(-) in transverse kinetic energy and rapidity, around the center-of-mass rapidity in 158 A GeV/c Pb + Pb collisions at the CERN SPS. A considerable enhancement of K+ production per pi is observed, as compared to p + p collisions at this energy. To illustrate the importance of secondary hadron rescattering as an enhancement mechanism, we compare strangeness production at the SPS and AGS with predictions of the transport model RQMD. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Niels Bohr Inst, DK-2100 Copenhagen, Denmark. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Columbia Univ, New York, NY 10027 USA. Nucl Phys Lab, F-44072 Nantes, France. Hiroshima Univ, Higashihiroshima 739, Japan. CERN, CH-1211 Geneva 23, Switzerland. Rudjer Boskovic Inst, Zagreb, Croatia. Texas A&M Univ, College Stn, TX 77843 USA. Ohio State Univ, Columbus, OH 43210 USA. SUNY Stony Brook, Stony Brook, NY 11794 USA. Univ Lund, S-22362 Lund, Sweden. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Bearden, I (reprint author), Niels Bohr Inst, Blegdamsvej 17, DK-2100 Copenhagen, Denmark. RI Bearden, Ian/M-4504-2014; OI Bearden, Ian/0000-0003-2784-3094; Gaardhoje, Jens-Jorgen/0000-0001-6122-4698 NR 23 TC 34 Z9 34 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 DEC 23 PY 1999 VL 471 IS 1 BP 6 EP 12 DI 10.1016/S0370-2693(99)01327-1 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 272JJ UT WOS:000084646500002 ER PT J AU Hirata, S Head-Gordon, M Bartlett, RJ AF Hirata, S Head-Gordon, M Bartlett, RJ TI Configuration interaction singles, time-dependent Hartree-Fock, and time-dependent density functional theory for the electronic excited states of extended systems SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID BODY PERTURBATION-THEORY; EXCITATION-ENERGIES; RESPONSE THEORY; HYDROGEN-FLUORIDE; DERIVATIVE DISCONTINUITIES; DYNAMIC POLARIZABILITIES; ABINITIO CALCULATIONS; NORMAL VIBRATIONS; ORBITAL THEORY; CHAIN MODELS AB A general formalism for time-dependent linear response theory is presented within the framework of linear-combination-of-atomic-orbital crystalline orbital theory for the electronic excited states of infinite one-dimensional lattices (polymers). The formalism encompasses those of time-dependent Hartree-Fock theory (TDHF), time-dependent density functional theory (TDDFT), and configuration interaction singles theory (CIS) (as the Tamm-Dancoff approximation to TDHF) as particular cases. These single-excitation theories are implemented by using a trial-vector algorithm, such that the atomic-orbital-based two-electron integrals are recomputed as needed and the transformation of these integrals from the atomic-orbital basis to the crystalline-orbital basis is avoided. Convergence of the calculated excitation energies with respect to the number of unit cells taken into account in the lattice summations (N) and the number of wave vector sampling points (K) is studied taking the lowest singlet and triplet exciton states of all-trans polyethylene as an example. The CIS and TDHF excitation energies of polyethylene show rapid convergence with respect to K and they are substantially smaller than the corresponding Hartree-Fock fundamental band gaps. In contrast, the excitation energies obtained from TDDFT and its modification, the Tamm-Dancoff approximation to TDDFT, show slower convergence with respect to K and the excitation energies to the lowest singlet exciton states tend to collapse to the corresponding Kohn-Sham fundamental band gaps in the limit of K -->infinity. We consider this to be a consequence of the incomplete cancellation of the self-interaction energy in the matrix elements of the TDDFT matrix eigenvalue equation, and to be a problem inherent to the current approximate exchange-correlation potentials that decay too rapidly in the asymptotic region. (C) 1999 American Institute of Physics. [S0021- 9606(99)30248-8]. C1 Univ Florida, Quantum Theory Project, Gainesville, FL 32611 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Hirata, S (reprint author), Univ Florida, Quantum Theory Project, Gainesville, FL 32611 USA. RI Bartlett, Rodney/F-6781-2011 OI Bartlett, Rodney/0000-0003-3865-9639 NR 80 TC 138 Z9 138 U1 5 U2 40 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 DEC 22 PY 1999 VL 111 IS 24 BP 10774 EP 10786 DI 10.1063/1.480443 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 265KB UT WOS:000084242200008 ER PT J AU Skinner, DE Miller, WH AF Skinner, DE Miller, WH TI Application of the forward-backward initial value representation to molecular energy transfer SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID THERMAL RATE CONSTANTS; SEMICLASSICAL APPROXIMATIONS; INELASTIC-COLLISIONS; VIBRATIONAL-MODES; TIME; DYNAMICS; SCATTERING; PROPAGATION; SYSTEMS AB It is shown how the forward-backward (FB) approximation to the semiclassical initial value representation (IVR) can be used to calculate the probability (or cross section) for molecular energy transfer. Specifically, the probability P(Delta E-A) for a molecule A to gain (or lose) an amount of internal energy Delta E-A by collision with a bath molecule B is given by the Fourier transform of a time correlation function C(t), which is in turn given by a single phase space average over the initial conditions of classical trajectories of the A+B collision system. Application to energy transfer of H-2 by collision with He is carried out to demonstrate that the FB-IVR provides a good description of quantum effects in P(Delta E-A). (C) 1999 American Institute of Physics. [S0021- 9606(99)01847-4]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Skinner, DE (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 55 TC 25 Z9 25 U1 0 U2 3 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 DEC 22 PY 1999 VL 111 IS 24 BP 10787 EP 10793 DI 10.1063/1.480444 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 265KB UT WOS:000084242200009 ER PT J AU Jacobson, GB Lee, CT Johnston, KP Tumas, W AF Jacobson, GB Lee, CT Johnston, KP Tumas, W TI Enhanced catalyst reactivity and separations using water/carbon dioxide emulsions SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID WATER; HYDROGENATION; MICROEMULSIONS; ENVIRONMENT; CHEMISTRY C1 Univ Calif Los Alamos Natl Lab, Catalysis Initiat Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Univ Texas, Dept Chem Engn, Austin, TX 78712 USA. RP Johnston, KP (reprint author), Univ Calif Los Alamos Natl Lab, Catalysis Initiat Chem Sci & Technol Div, POB 1663, Los Alamos, NM 87545 USA. NR 22 TC 96 Z9 98 U1 0 U2 12 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 DEC 22 PY 1999 VL 121 IS 50 BP 11902 EP 11903 DI 10.1021/ja993208x PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 270AF UT WOS:000084512700042 ER PT J AU Malinow, MR Bostom, AG Krauss, RH AF Malinow, MR Bostom, AG Krauss, RH TI Homocysteine and cardiovascular diseases - Response SO CIRCULATION LA English DT Letter C1 Oregon Reg Primate Res Ctr, Beaverton, OR 97006 USA. Brown Univ, Mem Hosp Rhode Isl, Div Gen & Internal Med, Pawtucket, RI 02860 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Malinow, MR (reprint author), Oregon Reg Primate Res Ctr, Beaverton, OR 97006 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0009-7322 J9 CIRCULATION JI Circulation PD DEC 21 PY 1999 VL 100 IS 25 BP E151 EP E151 PG 1 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 268AL UT WOS:000084391400047 ER PT J AU Hlavacek, WS Wofsy, C Perelson, AS AF Hlavacek, WS Wofsy, C Perelson, AS TI Dissociation of HIV-1 from follicular dendritic cells during HAART: Mathematical analysis SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID IMMUNODEFICIENCY-VIRUS TYPE-1; ANTIRETROVIRAL THERAPY; LYMPH-NODES; COMPLEMENT ACTIVATION; ASYMPTOMATIC PATIENTS; LIGAND-BINDING; PLASMA VIRUS; CR-2; RECEPTOR; INFECTION AB Follicular dendritic cells (FDC) provide a reservoir for HIV type 1 (HIV-1) that may reignite infection if highly active antiretroviral therapy (HAART) is withdrawn before virus on FDC is cleared. To estimate the treatment time required to eliminate HIV-1 on FDC, we develop deterministic and stochastic models for the reversible binding of HIV-1 to FDC via ligand-receptor interactions and examine the consequences of reducing the virus available for binding to FDC, Analysis of these models shows that the rate at which HIV-1 dissociates from FDC during HAART is biphasic, with an initial period of rapid decay followed by a period of slower exponential decay. The speed of the slower second stage of dissociation and the treatment time required to eradicate the FDC reservoir of HIV-1 are insensitive to the number of virions bound and their degree of attachment to FDC before treatment. In contrast, the expected time required for dissociation of an individual virion from FDC varies sensitively with the number of ligands attached to the virion that are available to interact with receptors on FDC. Although most virions may dissociate from FDC on the time scale of days to weeks, virions coupled to a higher-than-average number of ligands may persist on FDC for years. This result suggests that HAART may not be able to clear all HIV-1 trapped on FDC and that, even if clearance is possible, years of treatment will be required. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ New Mexico, Dept Math & Stat, Albuquerque, NM 87131 USA. RP Perelson, AS (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. FU NCRR NIH HHS [R01 RR006555, RR06555]; NIAID NIH HHS [AI28433, R01 AI028433, R37 AI028433] NR 44 TC 58 Z9 60 U1 0 U2 2 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 DEC 21 PY 1999 VL 96 IS 26 BP 14681 EP 14686 DI 10.1073/pnas.96.26.14681 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 267TM UT WOS:000084375400005 PM 10611272 ER PT J AU Yan, D Cho, HS Hastings, CA Igo, MM Lee, SY Pelton, JG Stewart, V Wemmer, DE Kustu, S AF Yan, D Cho, HS Hastings, CA Igo, MM Lee, SY Pelton, JG Stewart, V Wemmer, DE Kustu, S TI Beryllofluoride mimics phosphorylation of NtrC and other bacterial response regulators SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID ENHANCER-BINDING PROTEIN; ESCHERICHIA-COLI K-12; SIGNAL-TRANSDUCTION PROTEIN; 3-DIMENSIONAL STRUCTURE; SECONDARY STRUCTURE; ALUMINUM FLUORIDE; RECEIVER DOMAIN; Y PROTEIN; ACTIVATION; CHEMOTAXIS AB Two-component systems, sensor kinase-response regulator pairs, dominate bacterial signal transduction. Regulation is exerted by phosphorylation of an Asp in receiver domains of response regulators. Lability of the acyl phosphate linkage has limited structure determination for the active, phosphorylated forms of receiver domains. As assessed by both functional and structural criteria, beryllofluoride yields an excellent analogue of aspartyl phosphate in response regulator NtrC, a bacterial enhancer-binding protein. Beryllofluoride also appears to activate the chemotaxis, sporulation, osmosensing, and nitrate/nitrite response regulators CheY, SpoOF, OmpR, and NarL, respectively. NMR spectroscopic studies indicate that beryllofluoride will facilitate both biochemical and structural characterization of the active forms of receiver domains. C1 Univ Calif Berkeley, Dept Plant & Microbial Biol, Berkeley, CA 94720 USA. Univ Calif Berkeley, Grad Grp Biophys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA. Univ Calif Davis, Microbiol Sect, Davis, CA 95616 USA. RP Yan, D (reprint author), Univ Calif Berkeley, Dept Plant & Microbial Biol, Berkeley, CA 94720 USA. FU NIGMS NIH HHS [GM38361, R01 GM038361, R37 GM038361] NR 66 TC 108 Z9 109 U1 3 U2 7 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 DEC 21 PY 1999 VL 96 IS 26 BP 14789 EP 14794 DI 10.1073/pnas.96.26.14789 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 267TM UT WOS:000084375400024 PM 10611291 ER PT J AU Hillson, N Onuchic, JN Garcia, AE AF Hillson, N Onuchic, JN Garcia, AE TI Pressure-induced protein-folding/unfolding kinetics SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE pressure denaturation; hydrophobic effect; activation volumes; water penetration; energy landscape ID EGG-WHITE LYSOZYME; MOLECULAR-DYNAMICS; HYDROPHOBIC INTERACTIONS; STAPHYLOCOCCAL NUCLEASE; HYDROSTATIC-PRESSURE; FOLDING FUNNELS; MODEL; THERMODYNAMICS; STABILIZATION; DENATURATION AB We use an off-lattice minimalist model to describe the effects of pressure in slowing down the folding/unfolding kinetics of proteins when subjected to increasingly larger pressures. The potential energy function used to describe the interactions between beads in the model includes the effects of pressure on the pairwise interaction of hydrophobic groups in water. We show that pressure affects the participation of contacts in the transition state, More significantly, pressure exponentially decreases the chain reconfigurational diffusion coefficient. These results are consistent with experimental results on the kinetics of pressure-denaturation of staphylococcal nuclease. C1 Univ Calif Los Alamos Natl Lab, Theoret Biol & Biophys Grp, Los Alamos, NM 87545 USA. Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. RP Garcia, AE (reprint author), Univ Calif Los Alamos Natl Lab, Theoret Biol & Biophys Grp, POB 1663, Los Alamos, NM 87545 USA. RI Hillson, Nathan/F-9957-2012 OI Hillson, Nathan/0000-0002-9169-3978 NR 26 TC 91 Z9 91 U1 1 U2 13 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 DEC 21 PY 1999 VL 96 IS 26 BP 14848 EP 14853 DI 10.1073/pnas.96.26.14848 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 267TM UT WOS:000084375400034 PM 10611301 ER PT J AU Bailey, SM Meyne, J Chen, DJ Kurimasa, A Li, GC Lehnert, BE Goodwin, EH AF Bailey, SM Meyne, J Chen, DJ Kurimasa, A Li, GC Lehnert, BE Goodwin, EH TI DNA double-strand break repair proteins are required to cap the ends of mammalian chromosomes SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID SACCHAROMYCES-CEREVISIAE; TELOMERE LENGTH; MINOR SATELLITE; RECOMBINATION; YEAST; MOUSE; CELLS; MICE; GENE; IDENTIFICATION AB Recent findings intriguingly place DNA double-strand break repair proteins at chromosome ends in yeast, where they help maintain normal telomere length and structure. In the present study, an essential telomere function, the ability to cap and thereby protect chromosomes from end-to-end fusions, was assessed in repair-deficient mouse cell lines. By using fluorescence in situ hybridization with a probe to telomeric DNA, spontaneously occurring chromosome aberrations were examined for telomere signal at the points of fusion, a clear indication of impaired end-capping. Telomeric fusions were not observed in any of the repair-proficient controls and occurred only rarely in a p53 null mutant. In striking contrast, chromosomal end fusions that retained telomeric sequence were observed in nontransformed DNA-PKcs-deficient cells, where they were a major source of chromosomal instability. Metacentric chromosomes created by telomeric fusion became even more abundant in these cells after spontaneous immortalization. Restoration of repair proficiency through transfection with a functional cDNA copy of the human DNA-PKcs gene reduced the number of fusions compared with a negative transfection control. Virally transformed cells derived from Ku70 and Ku80 knockout mice also displayed end-to-end fusions, These studies demonstrate that DNA double-strand break repair genes play a dual role in maintaining chromosomal stability in mammalian cells, the known role in repairing incidental DNA damage, as well as a new protective role in telomeric end-capping. C1 Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Mem Sloan Kettering Canc Ctr, Dept Phys Med, New York, NY 10021 USA. RP Goodwin, EH (reprint author), Univ Calif Los Alamos Natl Lab, Div Life Sci, MS M888, Los Alamos, NM 87545 USA. FU NCI NIH HHS [R37 CA050519, CA50519, CA56909, CA78497, R01 CA050519, R01 CA056909] NR 43 TC 314 Z9 324 U1 0 U2 4 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 DEC 21 PY 1999 VL 96 IS 26 BP 14899 EP 14904 DI 10.1073/pnas.96.26.14899 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 267TM UT WOS:000084375400043 PM 10611310 ER PT J AU Blain, MG Stevens, JE Woodworth, JR AF Blain, MG Stevens, JE Woodworth, JR TI High-resolution submicron retarding field energy analyzer for low-temperature plasma analysis SO APPLIED PHYSICS LETTERS LA English DT Article AB A retarding potential energy analyzer having 750 nm diameter, self-aligned grid apertures and micron scale grid separation has been fabricated using polycrystalline silicon and silicon dioxide. High-resolution in situ measurements of ion velocity distributions have been demonstrated in inductively coupled argon plasmas. Measurement results agree well with those from a macroscopic analyzer. Important differences are observed in the energies of plasma ions when measured with respect to chamber wall versus those measured with respect to the plasma floating potential. Preliminary measurements under rf bias conditions have also been made and results follow the expected trends. (C) 1999 American Institute of Physics. [S0003-6951(99)00451-9]. C1 Sandia Natl Labs, Microelect Dev Lab, Albuquerque, NM 87185 USA. RP Blain, MG (reprint author), Sandia Natl Labs, Microelect Dev Lab, POB 5800, Albuquerque, NM 87185 USA. NR 6 TC 9 Z9 9 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 DEC 20 PY 1999 VL 75 IS 25 BP 3923 EP 3925 DI 10.1063/1.125495 PG 3 WC Physics, Applied SC Physics GA 265KG UT WOS:000084242700007 ER PT J AU Hochbauer, T Nastasi, M Mayer, JW AF Hochbauer, T Nastasi, M Mayer, JW TI Hydrogen blister depth in boron and hydrogen coimplanted n-type silicon SO APPLIED PHYSICS LETTERS LA English DT Article AB We have studied the depths of hydrogen surface blisters in < 100 > n-type silicon, which formed after B+H coimplantation and heat treatment. The silicon substrates had three different dopant levels, ranging from 10(14) to 10(19) cm(-3). The Si substrates were first implanted with B+ ions at 147 keV to a dose of 10(15) cm(-2). Some of the B-implanted samples were left in their as-implanted state; others were electrically activated by a rapid thermal anneal. The samples were then implanted with 40 keV H+ to a dose of 5x10(16) cm(-2). At the chosen implantation energies, the hydrogen- and boron-implantation distributions overlap. Following H+ implantation, all the samples were vacuum annealed and examined by ion-beam analysis and scanning electron microscopy. In all cases, the blister depth was consistently found to be strongly correlated with the H damage profile rather than the H or B concentration profiles. (C) 1999 American Institute of Physics. [S0003-6951(99)00851-7]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Arizona State Univ, Tempe, AZ 85287 USA. RP Hochbauer, T (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 16 TC 18 Z9 18 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 DEC 20 PY 1999 VL 75 IS 25 BP 3938 EP 3940 PG 3 WC Physics, Applied SC Physics GA 265KG UT WOS:000084242700012 ER PT J AU Oluseyi, HM Walker, ABC Santiago, DI Hoover, RB Barbee, TW AF Oluseyi, HM Walker, ABC Santiago, DI Hoover, RB Barbee, TW TI Observation and modeling of the solar transition region. II. Identification of new classes of solutions of coronal loop models SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : chromosphere; Sun : corona; Sun : transition region ID RAY BRIGHT POINTS; ENERGY-BALANCE; DIAGNOSTIC SPECTROMETER; MAGNETIC-STRUCTURE; ACTIVE REGIONS; FAST DOWNFLOWS; SCALING LAW; NETWORK; SUN; CHROMOSPHERE AB In the present work we undertake a study of the quasi-static loop model and the observational consequences of the various solutions found. We obtain the most general solutions consistent with certain initial conditions. Great care is exercised in choosing these conditions to be physically plausible (motivated by observations). We show that the assumptions of previous quasi-static loop models, such as the models of Rosner, Tucker, & Vaiana (RTV) and Veseckey, Antiochos, & Underwood, (VAU) are not necessarily valid for small loops at transition region temperatures. We find three general classes of solutions for the quasi-static loop model, which we denote radiation-dominated loops, conduction-dominated loops, and classical loops. These solutions are then compared with observations. Departures from the classical scaling law of RTV are found for the solutions obtained. It is shown that loops of the type that we model here can make a significant contribution to lower transition regions emission via thermal conduction from the upper transition region. C1 Stanford Univ, Dept Phys, Stanford, CA 94305 USA. Stanford Univ, Ctr Space Sci & Astrophys, Stanford, CA 94305 USA. Stanford Univ, Dept Phys & Appl Phys, Stanford, CA 94305 USA. NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. Lawrence Livermore Natl Lab, Dept Chem & Mat Sci, Livermore, CA 94550 USA. RP Stanford Univ, Dept Phys, Stanford, CA 94305 USA. EM Hakeem@Banneker.Stanford.edu; Walker@Banneker.Stanford.edu; David@spacetime.stanford.edu; Ricard.Hoover@msfc.nasa.gov; barbee2@llnl.gov NR 69 TC 15 Z9 15 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 1999 VL 527 IS 2 BP 992 EP 999 DI 10.1086/308113 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 270XD UT WOS:000084561700042 ER PT J AU Evslin, J Halpern, MB Wang, JE AF Evslin, J Halpern, MB Wang, JE TI General Virasoro construction on orbifold affine algebra SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article ID CONFORMAL FIELD-THEORY; MASTER EQUATION; MODELS; PRODUCTS AB We obtain the orbifold Virasoro master equation (OVME) at integer order lambda, which summarizes the general Virasoro construction on orbifold affine algebra. The OVME includes the Virasoro master equation when lambda = 1 and contains large classes of stress tensors of twisted sectors of conventional orbifolds at higher lambda. The generic construction is like a twisted sector of an orbifold (with nonzero ground state conformal weight) but new constructions are obtained for which we have so far found no conventional orbifold interpretation. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RP Evslin, J (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NR 34 TC 26 Z9 26 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD DEC 20 PY 1999 VL 14 IS 31 BP 4985 EP 5015 DI 10.1142/S0217751X99002360 PG 31 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 268YU UT WOS:000084448900007 ER PT J AU Abrikosov, AA AF Abrikosov, AA TI Theory of high-T-c superconducting cuprates based on experimental evidence SO INTERNATIONAL JOURNAL OF MODERN PHYSICS B LA English DT Article; Proceedings Paper CT 2nd International Conference on New Theories, Discoveries and Applicatins of Superconductors and Relates Materials (New3SC-2) CY MAY 31-JUN 04, 1999 CL LAS VEGAS, NEVADA ID HIGH-TEMPERATURE SUPERCONDUCTORS; SADDLE-POINT MODEL; UPPER CRITICAL-FIELD; ORDER-PARAMETER; FERMI-SURFACE; IMPURITIES; YBA2CU3O7; PARITY AB A model of superconductivity in layered high-temperature superconducting cuprates is proposed, based on the extended saddle point singularities in the electron spectrum, weak screening of the Coulomb interaction and phonon-mediated interaction between electrons plus a small short-range repulsion of Hund's, or spin-fluctuation, origin. This permits to explain the large values of T-c, features of the isotope effect on oxygen and copper, the existence of two types of the order parameter, the peak in the inelastic neutron scattering, the positive curvature of the upper critical field, as function of temperature etc. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Abrikosov, AA (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 26 TC 9 Z9 9 U1 1 U2 2 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0217-9792 J9 INT J MOD PHYS B JI Int. J. Mod. Phys. B PD DEC 20 PY 1999 VL 13 IS 29-31 BP 3405 EP 3418 DI 10.1142/S0217979299003118 PG 14 WC Physics, Applied; Physics, Condensed Matter; Physics, Mathematical SC Physics GA 273QT UT WOS:000084718900002 ER PT J AU Klemm, RA Arnold, G Bille, A Rieck, CT Scharnberg, K AF Klemm, RA Arnold, G Bille, A Rieck, CT Scharnberg, K TI c-axis twist Bi2Sr2CaCu2O8+delta Josephson junctions: A new phase-sensitive test of order parameter symmetry SO INTERNATIONAL JOURNAL OF MODERN PHYSICS B LA English DT Article; Proceedings Paper CT 2nd International Conference on New Theories, Discoveries and Applicatins of Superconductors and Relates Materials (New3SC-2) CY MAY 31-JUN 04, 1999 CL LAS VEGAS, NEVADA ID SUPERCONDUCTORS AB Li et al. found that the critical current density J(c)(J) across atomically clean c-axis twist junctions of Bi2Sr2CaCu2O8+delta is the same as that of the constituent single crystal, J(c)(S), independent of the twist angle phi(o), even at and below T-c. We investigated theoretically if a d(x)(2)-(2)(y)-wave order parameter might twist by mixing in d(xy)-wave components, but found that such mixing cannot possibly explain the data near to T-c. Combined with group theoretical arguments, we then conclude that the order parameter contains at least a substantial s- wave component, but does not contain any purported d(x)(2)-(2)(y)- wave component, except possibly below a second, unobserved phase transition. By studying tunneling models, we further conclude that the intrinsic c-axis Josephson tunneling in Bi2Sr2CaCu2O8+delta is likely to be mostly incoherent. We also propose a c-axis junction version of a tricrystal experiment, which does not rely upon expensive substrates. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. Univ Hamburg, Fachbereich Phys, D-20355 Hamburg, Germany. RP Klemm, RA (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 11 TC 11 Z9 11 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0217-9792 J9 INT J MOD PHYS B JI Int. J. Mod. Phys. B PD DEC 20 PY 1999 VL 13 IS 29-31 BP 3449 EP 3454 DI 10.1142/S0217979299003192 PG 6 WC Physics, Applied; Physics, Condensed Matter; Physics, Mathematical SC Physics GA 273QT UT WOS:000084718900010 ER PT J AU Brandow, B AF Brandow, B TI Characteristic features of the exotic superconductors: Evidence for a common pairing mechanism SO INTERNATIONAL JOURNAL OF MODERN PHYSICS B LA English DT Article; Proceedings Paper CT 2nd International Conference on New Theories, Discoveries and Applicatins of Superconductors and Relates Materials (New3SC-2) CY MAY 31-JUN 04, 1999 CL LAS VEGAS, NEVADA ID HEAVY-FERMION; RESISTIVITY; BEHAVIOR; CUPRATE; DENSITY AB We report on a comprehensive examination of the exotic superconductors (the materials so-labelled by Uemura and co-workers), to determine as far as possible the true systematics among their many anomalous features. In the crystal-chemistry aspects as well as in the electronic properties, we find features which appear to be universal for these materials, and also features which are clearly not universal but which are common enough to be considered typical for these materials. a number of implications are presented. There is strong evidence that all of these materials are sharing some "new" pairing mechanism, usually in addition to the conventional phonon mechanism. C1 Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. RP Brandow, B (reprint author), Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. NR 24 TC 2 Z9 2 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0217-9792 J9 INT J MOD PHYS B JI Int. J. Mod. Phys. B PD DEC 20 PY 1999 VL 13 IS 29-31 BP 3482 EP 3488 DI 10.1142/S0217979299003258 PG 7 WC Physics, Applied; Physics, Condensed Matter; Physics, Mathematical SC Physics GA 273QT UT WOS:000084718900016 ER PT J AU Graf, MJ Balatsky, AV Sauls, JA AF Graf, MJ Balatsky, AV Sauls, JA TI Spin-orbit scattering in d(x2-y2) superconductors SO INTERNATIONAL JOURNAL OF MODERN PHYSICS B LA English DT Article; Proceedings Paper CT 2nd International Conference on New Theories, Discoveries and Applicatins of Superconductors and Relates Materials (New3SC-2) CY MAY 31-JUN 04, 1999 CL LAS VEGAS, NEVADA DE spin-orbit scattering; magnetic impurities; broken time-reversal symmetry; unconventional superconductors ID UNCONVENTIONAL SUPERCONDUCTORS; MAGNETIC-IMPURITIES; TIME-REVERSAL; SYMMETRY; STATE; PHASE AB We show that spin-orbit scattering off an isolated magnetic impurity in a singlet d(x)(2)-(2)(y) superconductor generates a d(xy) order parameter with locally broken time-reversal symmetry. A consequence of the induced d(xy) component are orbital charge currents and a magnetic field in the vicinity of the magnetic impurity. C1 Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Theory, Los Alamos, NM 87545 USA. Northwestern Univ, Dept Phys & Astron, Evanston, IL 60208 USA. RP Graf, MJ (reprint author), Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. NR 14 TC 1 Z9 1 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0217-9792 J9 INT J MOD PHYS B JI Int. J. Mod. Phys. B PD DEC 20 PY 1999 VL 13 IS 29-31 BP 3513 EP 3515 DI 10.1142/S0217979299003325 PG 3 WC Physics, Applied; Physics, Condensed Matter; Physics, Mathematical SC Physics GA 273QT UT WOS:000084718900023 ER PT J AU Dessau, DS Chuang, YD Gromko, AD Aiura, Y Yamaguchi, Y Oka, K Arko, AJ Joyce, J Eisaki, H Uchida, SI Nakamura, K Ando, Y AF Dessau, DS Chuang, YD Gromko, AD Aiura, Y Yamaguchi, Y Oka, K Arko, AJ Joyce, J Eisaki, H Uchida, SI Nakamura, K Ando, Y TI A re-examination of the electronic structure and Fermi Surface of BSCCO SO INTERNATIONAL JOURNAL OF MODERN PHYSICS B LA English DT Article; Proceedings Paper CT 2nd International Conference on New Theories, Discoveries and Applicatins of Superconductors and Relates Materials (New3SC-2) CY MAY 31-JUN 04, 1999 CL LAS VEGAS, NEVADA AB We have perfomed angle-resolved photoemission (ARPES) experiments on a variety of Bi-Sr-Ca-Cu-O (BSCCO)samples. By applying a stricter set of FS crossing criteria as well as by varying the incident photon energy outside the usual range, we have found very different behavior from that previously observed. Instead of being centered around the X or Y points and having hole-like character, we argue that the FS is centered around the Gamma point and contains electron-like portions. In addition, the flat bands just below E-F around (M) over bar are not observed at the photon energy of 33eV, raising questions about the origin of these states. C1 Univ Colorado, Dept Phys, Boulder, CO 80309 USA. Electrotech Lab ETL, Tsukuba, Ibaraki 305, Japan. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Tokyo, Dept Superconductiv, Bunkyo Ku, Tokyo 113, Japan. Cent Res Inst Elect Power Ind, Tokyo 2018511, Japan. RP Dessau, DS (reprint author), Univ Colorado, Dept Phys, Boulder, CO 80309 USA. RI Ando, Yoichi/B-8163-2013 OI Ando, Yoichi/0000-0002-3553-3355 NR 5 TC 1 Z9 1 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0217-9792 J9 INT J MOD PHYS B JI Int. J. Mod. Phys. B PD DEC 20 PY 1999 VL 13 IS 29-31 BP 3597 EP 3600 DI 10.1142/S0217979299003507 PG 4 WC Physics, Applied; Physics, Condensed Matter; Physics, Mathematical SC Physics GA 273QT UT WOS:000084718900041 ER PT J AU Almasan, CC Levin, GA Cimpoiasu, E Stein, T Zhang, CL DeAndrade, MC Maple, MB Zheng, H Paulikas, AP Veal, BW AF Almasan, CC Levin, GA Cimpoiasu, E Stein, T Zhang, CL DeAndrade, MC Maple, MB Zheng, H Paulikas, AP Veal, BW TI Relationship between conductivity and phase coherence length in cuprates SO INTERNATIONAL JOURNAL OF MODERN PHYSICS B LA English DT Article; Proceedings Paper CT 2nd International Conference on New Theories, Discoveries and Applicatins of Superconductors and Relates Materials (New3SC-2) CY MAY 31-JUN 04, 1999 CL LAS VEGAS, NEVADA AB The large (10(2) - 10(5)) and strongly temperature dependent resistive anisotropy eta = (sigma(ab)/sigma(c))(1/2) of cuprates perhaps holds the key to understanding their normal state inplane sigma(ab) and out-of-plane sigma(c) conductivities. It can be shown that eta is determined by the ratio of the phase coherence lengths l(i) in the respective directions: sigma(ab)/sigma(c) = l(ab)(2)/l(c)(2). In layered crystals in which the out-of-plane transport is incoherent, l(c) is fixed, equal to the interlayer spacing. As a result, the T-dependence of eta is determined by that of l(ab), and vice verse, the in-plane phase coherence length can be obtained directly by measuring the resistive anisotropy. We present data for hole-doped YBa2Cu3Oy (6.3 < y < 6.9) and Y1-xPrxBa2Cu3O7-delta (0 < x less than or equal to 0.55) and show that sigma(ab) of crystals with different doping levels can be well described by a two parameter universal function of the in-plane phase coherence length. In the electron-doped Nd2-xCexCuO4-y, the dependence sigma(ab)(eta) indicates a crossover from incoherent to coherent transport in the c-direction. C1 Kent State Univ, Dept Phys, Kent, OH 44242 USA. Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. Univ Calif San Diego, Inst Pure & Appl Phys Sci, La Jolla, CA 92093 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Almasan, CC (reprint author), Kent State Univ, Dept Phys, Kent, OH 44242 USA. NR 3 TC 3 Z9 3 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0217-9792 J9 INT J MOD PHYS B JI Int. J. Mod. Phys. B PD DEC 20 PY 1999 VL 13 IS 29-31 BP 3618 EP 3622 DI 10.1142/S0217979299003556 PG 5 WC Physics, Applied; Physics, Condensed Matter; Physics, Mathematical SC Physics GA 273QT UT WOS:000084718900046 ER PT J AU Mesot, J Norman, MR Fretwell, HM Kaminski, A Campuzano, JC Ding, H Randeria, M Paramekanti, A Takeuchi, T Mochiku, T Yokoya, T Sato, T Takahashi, T Kadowaki, K AF Mesot, J Norman, MR Fretwell, HM Kaminski, A Campuzano, JC Ding, H Randeria, M Paramekanti, A Takeuchi, T Mochiku, T Yokoya, T Sato, T Takahashi, T Kadowaki, K TI Changes in superconducting gap anisotropy with doping and implications for the penetration depth SO INTERNATIONAL JOURNAL OF MODERN PHYSICS B LA English DT Article; Proceedings Paper CT 2nd International Conference on New Theories, Discoveries and Applicatins of Superconductors and Relates Materials (New3SC-2) CY MAY 31-JUN 04, 1999 CL LAS VEGAS, NEVADA DE superconductivity; ARPES; quasiparticle; interaction ID BI2SR2CACU2O8+DELTA; STATE AB The momentum dependence of the superconducting gap at low temperatures is precisely determined from angle resolved photoemission (ARPES) measurements on overdoped and underdoped samples of Bi2212. As the doping decreases, the maximum gap increases, but the slope of the gap near the nodes decreases. Though consistent with d-wave symmetry, the gap with underdoping cannot be fit by the simple cos(k(x)) - cos(k(y)) form. We suggest that this arises due to the increasing importance of long range interactions as one approaches the insulator. Furthermore, a comparison of our ARPES results with available penetration depth data clearly indicates that the renormalization of the linear T suppression of the superfluid density at low temperatures due to quasiparticle excitations around the d-wave nodes is large and doping dependent. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Univ Illinois, Dept Phys, Chicago, IL 60607 USA. Boston Coll, Dept Phys, Chestnut Hill, MA 02467 USA. Tata Inst Fundamental Res, Bombay 400005, Maharashtra, India. Nagoya Univ, Dept Crystalline Mat Sci, Nagoya, Aichi 46401, Japan. Natl Res Inst Met, Tsukuba, Ibaraki 305, Japan. Tohoku Univ, Dept Phys, Sendai, Miyagi 9808578, Japan. Univ Tsukuba, Inst Mat Sci, Tsukuba, Ibaraki 305, Japan. RP Mesot, J (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Tohoku, Arpes/A-4890-2010; Takahashi, Takashi/E-5080-2010; Norman, Michael/C-3644-2013; YOKOYA, Takayoshi/B-1478-2011 NR 8 TC 0 Z9 0 U1 0 U2 5 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0217-9792 J9 INT J MOD PHYS B JI Int. J. Mod. Phys. B PD DEC 20 PY 1999 VL 13 IS 29-31 BP 3709 EP 3711 DI 10.1142/S0217979299003726 PG 3 WC Physics, Applied; Physics, Condensed Matter; Physics, Mathematical SC Physics GA 273QT UT WOS:000084718900063 ER PT J AU Naugle, DG Rathnayaka, KDD Clark, K Canfield, PC AF Naugle, DG Rathnayaka, KDD Clark, K Canfield, PC TI Critical field and magnetoresistance of single crystal TmNi2B2C SO INTERNATIONAL JOURNAL OF MODERN PHYSICS B LA English DT Article; Proceedings Paper CT 2nd International Conference on New Theories, Discoveries and Applicatins of Superconductors and Relates Materials (New3SC-2) CY MAY 31-JUN 04, 1999 CL LAS VEGAS, NEVADA ID SUPERCONDUCTING PROPERTIES; TRANSPORT AB In-plane resistance as a function of magnitude and direction of the magnetic field and the temperature has been measured for TmNi2B2C from above the superconducting transition temperature at 10.7 K to below the magnetic transition T-N=1.5 K. The superconducting upper critical field H-c2(T) exhibits a large anisotropy and structure in the vicinity of T-N. The magnetoresistance above T-C is large and changes sign as the direction of the magnetic field is rotated from in-plane to parallel with the c-axis. C1 Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys, Ames, IA 50011 USA. RP Naugle, DG (reprint author), Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. RI Canfield, Paul/H-2698-2014 NR 8 TC 6 Z9 6 U1 0 U2 4 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0217-9792 J9 INT J MOD PHYS B JI Int. J. Mod. Phys. B PD DEC 20 PY 1999 VL 13 IS 29-31 BP 3715 EP 3717 DI 10.1142/S021797929900374X PG 3 WC Physics, Applied; Physics, Condensed Matter; Physics, Mathematical SC Physics GA 273QT UT WOS:000084718900065 ER PT J AU Ozyuzer, L Zasadzinski, JF Miyakawa, N AF Ozyuzer, L Zasadzinski, JF Miyakawa, N TI Tunneling spectra and superconducting gap in Bi2Sr2CaCu2O8+delta and Tl(2)ba(2)CuO(6-delta) SO INTERNATIONAL JOURNAL OF MODERN PHYSICS B LA English DT Article; Proceedings Paper CT 2nd International Conference on New Theories, Discoveries and Applicatins of Superconductors and Relates Materials (New3SC-2) CY MAY 31-JUN 04, 1999 CL LAS VEGAS, NEVADA ID OVERDOPED BI2SR2CACU2O8+DELTA; TEMPERATURE AB Tunneling spectra are reported for Bi2Sr2CaCu2O8+delta (Bi-2212) over a wide doping range using superconductor-insulator-superconductor (SIS) break junctions. The energy gap inferred from the tunneling data displays a remarkable monotonic dependence on doping, increasing to very large values in the underdoped region even as T-c decreases. This leads to unphysically large values of the strong coupling ratio (similar to 20). The tunneling spectra are qualitatively similar over the entire doping range even though the gap parameter, Delta, changes from 12 meV to 60 meV. Each spectrum exhibits dip and hump features at high bias with characteristic energies that scale with the superconducting gap. Tunneling spectra of near optimally-doped Tl2Ba2CuO6+delta (Tl-2201) also display a weak dip feature in superconductor-insulator-normal metal (SIN) junctions. Generated SIS spectra of Tl-2201 are compared with measured spectra on Bi-2212 and it is concluded that the dip and hump features are generic to high temperature superconductors. C1 Argonne Natl Lab, Argonne, IL 60439 USA. IIT, Chicago, IL 60616 USA. Sci Univ Tokyo, Tokyo 162, Japan. RP Ozyuzer, L (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Ozyuzer, Lutfi/H-3142-2011 NR 11 TC 17 Z9 17 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0217-9792 J9 INT J MOD PHYS B JI Int. J. Mod. Phys. B PD DEC 20 PY 1999 VL 13 IS 29-31 BP 3721 EP 3724 DI 10.1142/S0217979299003763 PG 4 WC Physics, Applied; Physics, Condensed Matter; Physics, Mathematical SC Physics GA 273QT UT WOS:000084718900067 ER PT J AU Rathnayaka, KDD Naugle, DG Li, S de Andrade, MC Dickey, RP Amann, A Maple, MB Bud'ko, SL Canfield, PC Beyermann, WP AF Rathnayaka, KDD Naugle, DG Li, S de Andrade, MC Dickey, RP Amann, A Maple, MB Bud'ko, SL Canfield, PC Beyermann, WP TI Transition from heavy fermion metal to 16 K superconductor in single crystal YbxLu(1-x)Ni2B2C: transport studies SO INTERNATIONAL JOURNAL OF MODERN PHYSICS B LA English DT Article; Proceedings Paper CT 2nd International Conference on New Theories, Discoveries and Applicatins of Superconductors and Relates Materials (New3SC-2) CY MAY 31-JUN 04, 1999 CL LAS VEGAS, NEVADA ID UPPER CRITICAL-FIELD; BEHAVIOR; YBNI2B2C; LUNI2B2C AB YbNi2B2C has been found to be a heavy fermion metal with neither superconductivity nor magnetic order in contrast to the other members of the borocarbide family. LuNi2B2C is a superconductor with T-c similar to 16.3K and no magnetic order. Transport studies on single crystal YbxLu(1-x)Ni2B2C show a systematic change from a heavy fermion system to a moderately high-temperature superconductor. A "giant" thermopower is observed for small x to x=1, i.e., in the transition region from a Kondo alloy to a heavy fermion metal. Measurements of H-c2(T,x) are also reported for x<0.15. C1 Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys, Ames, IA 50011 USA. Univ Calif Riverside, Dept Phys, Riverside, CA 92521 USA. RP Rathnayaka, KDD (reprint author), Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. RI Canfield, Paul/H-2698-2014 NR 12 TC 3 Z9 3 U1 0 U2 1 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0217-9792 J9 INT J MOD PHYS B JI Int. J. Mod. Phys. B PD DEC 20 PY 1999 VL 13 IS 29-31 BP 3725 EP 3728 DI 10.1142/S0217979299003775 PG 4 WC Physics, Applied; Physics, Condensed Matter; Physics, Mathematical SC Physics GA 273QT UT WOS:000084718900068 ER PT J AU Rosenkranz, S Osborn, R Mitchell, JF Vasiliu-Doloc, L Lynn, JW Sinha, SK AF Rosenkranz, S Osborn, R Mitchell, JF Vasiliu-Doloc, L Lynn, JW Sinha, SK TI Spin correlations of the magnetoresistive bilayer manganite La1.2Sr1.8Mn2O7 SO INTERNATIONAL JOURNAL OF MODERN PHYSICS B LA English DT Article; Proceedings Paper CT 2nd International Conference on New Theories, Discoveries and Applicatins of Superconductors and Relates Materials (New3SC-2) CY MAY 31-JUN 04, 1999 CL LAS VEGAS, NEVADA ID COLOSSAL-MAGNETORESISTANCE; LAYERED LA1.2SR1.8MN2O7; GIANT MAGNETORESISTANCE; RB2CRCL4; BEHAVIOR AB We review our recent neutron and X-ray scattering studies of the 40% hole doped bilayer manganite La1.2Sr1.8Mn2O7,, which exhibits colossal magnetoresistance above the ferromagnetic transition st T-C similar to 113 K. In the paramagnetic region, static diffuse scattering reveals the existence of correlated charges. However, the good agreement of the in-plane spin correlations with the conventional model for quasi two-dimensional XY magnets indicates that the metal-insulator transition is driven by the growth of magnetic correlations. Across the transition, the competition between antiferromagnetic superexchange and ferromagnetic double exchange, observed as canted correlations between spins in neighboring layers within each bilayer, is strongly reduced, indicating a direct link of the double exchange interaction to the hole mobility. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Natl Inst Stand & Technol, NIST Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Rosenkranz, S (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Rosenkranz, Stephan/E-4672-2011; Osborn, Raymond/E-8676-2011 OI Rosenkranz, Stephan/0000-0002-5659-0383; Osborn, Raymond/0000-0001-9565-3140 NR 18 TC 0 Z9 0 U1 0 U2 1 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0217-9792 J9 INT J MOD PHYS B JI Int. J. Mod. Phys. B PD DEC 20 PY 1999 VL 13 IS 29-31 BP 3820 EP 3822 DI 10.1142/S0217979299003982 PG 3 WC Physics, Applied; Physics, Condensed Matter; Physics, Mathematical SC Physics GA 273QT UT WOS:000084718900089 ER PT J AU Beeri, O Cohen, D Gavra, Z Johnson, JR Mintz, MH AF Beeri, O Cohen, D Gavra, Z Johnson, JR Mintz, MH TI High-pressure studies of Laves phase intermetallic hydrides - Adaptation of statistical thermodynamic models SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT International Symposium on Metal-Hydrogen Systems, Fundamentals and Applications CY OCT 04-09, 1998 CL ZHEJIANG, PEOPLES R CHINA SP Zhejiang Univ DE high-pressure; hydrides; TiCr1.8; thermodynamics; statistical-thermodynamics ID TEMPERATURE; HYDROGEN AB Pressure-composition isotherms of unstable intermetallic hydrides of some Laves phases (TiCr-2, TiCrMn) were measured over a wide pressure range up to 1000 atm H-2. These measurements enabled the evaluation of the critical temperatures, T-c, of the respective systems as well as the derivation of their thermodynamic characteristics above T-c. For this one-phase high-temperature range, simplified statistical-thermodynamics models can be adapted to calculate analytical forms of the corresponding isotherms. A comparison between the model-derived and the experimental isotherms then yields the average pairwise nearest neighbor H-H interaction parameter, eta, and its temperature dependence. In the present study, a rigid-metal sublattice model was utilized and solved employing the conventional Bragg-Williams (BW) and Quasi-Chemical(QC) approximations. In fact, both approximations resulted in similar eta(T) values, as well as close estimates of T-c. For the TiCr-2-H-2 system the above analysis indicated that eta changes from attractive (i.e., negative) to repulsive (i.e., positive) with increasing isotherm temperatures. This trend was qualitatively interpreted as resulting from the net interplay of two energy terms, the elastic strain contribution, which induces an effective attractive interaction, and the electrostatic contribution which adds a repulsive term. For the TiCrMn-H-2 system, it turned out that the partial substitution of chromium by manganese had only a minor effect on the stability of the hydride, however, it pronouncedly increased the critical temperature (T-c) of the system. This observation can be accounted for by the simultaneous electronic and structural effects of manganese in this compound. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Nucl Res Ctr Negev, IL-84190 Beer Sheva, Israel. Ben Gurion Univ Negev, IL-84105 Beer Sheva, Israel. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Beeri, O (reprint author), Nucl Res Ctr Negev, POB 9001, IL-84190 Beer Sheva, Israel. OI cohen, dror/0000-0001-9197-6030 NR 15 TC 7 Z9 7 U1 0 U2 2 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 DEC 20 PY 1999 VL 293 BP 14 EP 18 DI 10.1016/S0925-8388(99)00382-5 PG 5 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 262KD UT WOS:000084065500005 ER PT J AU Shanahan, KL Holder, JS Wermer, JR AF Shanahan, KL Holder, JS Wermer, JR TI Tritium aging effects in palladium on kieselguhr SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT International Symposium on Metal-Hydrogen Systems, Fundamentals and Applications CY OCT 04-09, 1998 CL ZHEJIANG, PEOPLES R CHINA SP Zhejiang Univ DE tritium; palladium; kieselguhr; silica; aging; hydride ID HELIUM RELEASE; DECAY AB Fifty wt% Pd on kieselguhr (Pd/k) is used in hydrogen isotope separation processes at the Savannah River Site. Long-term aging studies on this material were undertaken in June 1992. P-c-T data showing the aging effect of tritium loading for long periods will be presented and discussed covering from June 1992 to March 1998. Lowering of plateau pressures and increasing indications of inhomogeneities have been observed in both tritium and deuterium absorption isotherms at 0 degrees C, and desorption isotherms at 80 and 120 degrees C. (C) 1999 Westinghouse Savannah River Company. Published by Elsevier Science S.A. All rights reserved. C1 Westinghouse Savannah River Co, Savannah River Technol Ctr, Aiken, SC 29808 USA. RP Shanahan, KL (reprint author), Westinghouse Savannah River Co, Savannah River Technol Ctr, Aiken, SC 29808 USA. NR 12 TC 11 Z9 13 U1 1 U2 6 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 DEC 20 PY 1999 VL 293 BP 62 EP 66 DI 10.1016/S0925-8388(99)00302-3 PG 5 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 262KD UT WOS:000084065500014 ER PT J AU Heung, LK Wicks, CG AF Heung, LK Wicks, CG TI Silica embedded metal hydrides SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT International Symposium on Metal-Hydrogen Systems, Fundamentals and Applications CY OCT 04-09, 1998 CL ZHEJIANG, PEOPLES R CHINA SP Zhejiang Univ DE metal hydride; silica composite; porous AB A new class of composite materials were developed which encapsulate metal hydride particles in a porous silica matrix. The particles were embedded in two different types of silica matrices, which successfully converted the small metal hydride particles into large granules suitable for packing gas separation columns. The granules absorbed hydrogen readily and withstood many hydrogen absorption cycles without producing fines. The porosity of the silica matrices was optimized so that the pores were large enough to allow hydrogen to easily move within the matrix and react with the metal hydride particles, but small enough to art as a filter to prevent passage of larger molecule including harmful impurities. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Westinghouse Savannah River Co, Aiken, SC 29808 USA. RP Heung, LK (reprint author), Westinghouse Savannah River Co, 773-A,Savannah River Site, Aiken, SC 29808 USA. NR 3 TC 11 Z9 13 U1 0 U2 2 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 DEC 20 PY 1999 VL 293 BP 446 EP 451 DI 10.1016/S0925-8388(99)00333-3 PG 6 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 262KD UT WOS:000084065500087 ER PT J AU Reilly, JJ Adzic, GD Johnson, JR Vogt, T Mukerjee, S McBreen, J AF Reilly, JJ Adzic, GD Johnson, JR Vogt, T Mukerjee, S McBreen, J TI The correlation between composition and electrochemical properties of metal hydride electrodes SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT International Symposium on Metal-Hydrogen Systems, Fundamentals and Applications CY OCT 04-09, 1998 CL ZHEJIANG, PEOPLES R CHINA SP Zhejiang Univ DE metal hydride electrodes; MH/Ni batteries ID ABSORPTION FINE-STRUCTURE; HYDROGEN STORAGE ALLOYS; X-RAY; INTERMETALLIC COMPOUNDS; NEUTRON-DIFFRACTION; CYCLING STABILITY; FORMING COMPOUNDS; SYSTEM; BATTERY; BEHAVIOR AB This paper is concerned with an overview of the properties of metal hydride electrodes used for battery applications. The emphasis is on the properties of AB(5) electrodes but others are treated as well. The review begins with a brief discussion of the pertinent chemistry of hydrogen in metals, the properties of intermetallic hydrides and their relation to electrochemical behavior. Systematic guidelines which permit the modification of such properties for electrochemical applications are discussed. The electrochemical behaviors of certain specific AB(5) alloy electrodes are covered in detail, emphasizing the effects of composition changes with respect to both the A and the B components. The consequences of electrode expansion and contraction with respect to hydride formation and decomposition are discussed quantitatively. Novel alloy compositions and phases are noted and evaluated. The attractive properties of cobalt-free, non-stoichiometric AB(5+x) electrodes are noted. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. RP Reilly, JJ (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. RI Vogt, Thomas /A-1562-2011 OI Vogt, Thomas /0000-0002-4731-2787 NR 67 TC 125 Z9 145 U1 3 U2 25 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 DEC 20 PY 1999 VL 293 BP 569 EP 582 DI 10.1016/S0925-8388(99)00413-2 PG 14 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 262KD UT WOS:000084065500109 ER PT J AU Zaveri, RA Peters, LK AF Zaveri, RA Peters, LK TI A new lumped structure photochemical mechanism for large-scale applications SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GAS-PHASE REACTIONS; SMOG REACTION-MECHANISMS; VOLATILE ORGANIC-COMPOUNDS; TROPOSPHERIC SULFUR CYCLE; ACID DEPOSITION MODEL; ATMOSPHERIC CHEMISTRY; CHEMICAL MECHANISM; DETAILED MECHANISM; TRANSITORY PRODUCT; CARBONYL PRODUCTS AB The lumped-structure approach for condensing organic chemical mechanisms is attractive, since it yields fewer species and reactions and reduces computational costs. This paper leads through the development of a new lumped-structure mechanism, largely based on the widely used Carbon Bond Mechanism (CBM-IV) developed by Gery et al. [1989]. The new mechanism called CBM-Z extends the original framework to function properly at larger spatial and longer timescales. The major modifications in the mechanism include revised inorganic chemistry; explicit treatment of the lesser reactive paraffins, methane and ethane; revised parameterizations of the reactive paraffin, olefin, and aromatic reactions; inclusion of alkyl and acyl peroxy radical interactions and their reactions with NO3; inclusion of organic nitrates and hydroperoxides; and refined isoprene chemistry based on the condensed one-product mechanism of Carter [1996]. CBM-Z was successfully evaluated along with the CBM-IV, a partially revised CBM-IV, and a revised Regional Acid Deposition Model (RADM2) mechanism [Stockwell et al., 1990; Kirchner and Stockwell, 1996] using the low NO, and volatile organic compound concentration smog chamber experiments of Simonaitis et al. [1997]. Box model versions of the four mechanisms were also evaluated under a variety of hypothetical urban and rural scenarios for a period of 30 days. Results from CBM-Z and revised RADM2 were found to be within +/-20% of each other, while CBM-IV and revised CBM-IV results deviated significantly by up to 50-95%. Sensitivity tests were performed to elucidate the effects of some of the new features added in CBM-Z. Relative computational memory and time requirements of these mechanisms are also discussed. C1 Pacific NW Natl Lab, Atmospher Sci Tech Grp, Richland, WA 99352 USA. Virginia Polytech Inst & State Univ, Dept Chem Engn, Blacksburg, VA 24061 USA. RP Zaveri, RA (reprint author), Pacific NW Natl Lab, Atmospher Sci Tech Grp, Richland, WA 99352 USA. EM Rahul.Zaveri@pnl.gov; petersl@vt.edu OI Zaveri, Rahul/0000-0001-9874-8807 NR 68 TC 209 Z9 229 U1 8 U2 43 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 20 PY 1999 VL 104 IS D23 BP 30387 EP 30415 DI 10.1029/1999JD900876 PG 29 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 268DR UT WOS:000084399500020 ER PT J AU Chen, JB Angelici, RJ AF Chen, JB Angelici, RJ TI Reactions of Co-4(CO)(12) and Cr(CO)(6) with dibenzothiophene and benzothiophene SO ORGANOMETALLICS LA English DT Article ID SULFUR BOND-CLEAVAGE; COMPLEXES; RUTHENIUM; THIOPHENE; MODELS; COBALT AB Reaction of Co-4(CO)(12) With dibenzothiophene (DBT) gives (eta(6)-DBT)Co-4(CO)(9) (1), in which one arene ring of DBT is eta(6)-coordinated to a Co. This cluster 1 reacts with Cr(CO)(6) to give (eta(6)-DBT)Cr(CO)(3) and [CO)(3)Cr](2)(mu-DBT) but reacts with Cr(CO)(3)(NCMe)(3) to give the desulfurized (eta(6)-benzene)Co-4(CO)(9) (4). Benzothiophene yields the same desulfurized product 4 upon reaction with Co-4(CO)(12). C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Chinese Acad Sci, Shanghai Inst Organ Chem, Shanghai 200032, Peoples R China. RP Angelici, RJ (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 19 TC 12 Z9 12 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD DEC 20 PY 1999 VL 18 IS 26 BP 5721 EP 5724 DI 10.1021/om990675e PG 4 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA 271FQ UT WOS:000084583900043 ER PT J AU Bart, S Chrien, RE Franklin, WA Fukuda, T Hayano, RS Hicks, K Hungerford, EV Michael, R Miyachi, T Nagae, T Nakano, J Naing, W Omata, K Sawafta, R Shimizu, Y Tang, L Wissink, SW AF Bart, S Chrien, RE Franklin, WA Fukuda, T Hayano, RS Hicks, K Hungerford, EV Michael, R Miyachi, T Nagae, T Nakano, J Naing, W Omata, K Sawafta, R Shimizu, Y Tang, L Wissink, SW TI Sigma Hyperons in the Nucleus SO PHYSICAL REVIEW LETTERS LA English DT Article ID HE-4(SIGMA) BOUND-STATE; 600 MEV/C AB A search for Sigma hypernuclear states in p-shell hypernuclei her; been performed with the Moby Dick spectrometer and the low energy separated beam (LESB-2) at the Brookhaven Alternating Gradient Synchrotron (BNL AGS). Unlike some previously published reports, no narrow states have been observed for targets of Li-6 and Be-9 in (K-, pi(+/-)) reactions, either for bound state or continuum regions, Together with the previously reported J = 0, T = 1/2 bound state in He-4(Sigma), these results demonstrate the crucial role of isospin in Sigma hypernuclei. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Hampton Univ, Hampton, VA 23668 USA. Indiana Univ, Cyclotron Facil, Bloomington, IN 47408 USA. KEK, Inst Particle & Nucl Studies, Tsukuba, Ibaraki 3050801, Japan. N Carolina Agr & Technol State Univ, Greensboro, NC 27411 USA. Ohio Univ, Athens, OH 45071 USA. Osaka Univ, Dept Phys, Toyonaka, Osaka 5600043, Japan. Univ Houston, Houston, TX 77204 USA. Univ Tokyo, Tokyo 1130033, Japan. RP Bart, S (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. RI Hayano, Ryugo/F-7889-2012 OI Hayano, Ryugo/0000-0002-1214-7806 NR 18 TC 91 Z9 96 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 DEC 20 PY 1999 VL 83 IS 25 BP 5238 EP 5241 DI 10.1103/PhysRevLett.83.5238 PG 4 WC Physics, Multidisciplinary SC Physics GA 266LH UT WOS:000084301100014 ER PT J AU Sheehy, B Martin, JDD DiMauro, LF Agostini, P Schafer, KJ Gaarde, MB Kulander, KC AF Sheehy, B Martin, JDD DiMauro, LF Agostini, P Schafer, KJ Gaarde, MB Kulander, KC TI High harmonic generation at long wavelengths SO PHYSICAL REVIEW LETTERS LA English DT Article ID HIGH-ORDER HARMONICS; THRESHOLD IONIZATION; LASER-PULSES AB High harmonic radiation spectra up to 19th order in alkali metal vapors excited by an intense, picosecond mid-infrared (3 -4 mu m) laser are reported and compared to theory. The strong-field dynamics in the alkali metal atoms exhibit significant differences from all previously studied systems due to the strong coupling between their ground and first excited states. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Ctr Etud Saclay, SPAM, F-91191 Gif Sur Yvette, France. Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA. Lund Inst Technol, Dept Phys, S-22100 Lund, Sweden. Univ Calif Lawrence Livermore Natl Lab, TAMP, Livermore, CA 94551 USA. RP Sheehy, B (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. NR 17 TC 71 Z9 71 U1 2 U2 16 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 DEC 20 PY 1999 VL 83 IS 25 BP 5270 EP 5273 DI 10.1103/PhysRevLett.83.5270 PG 4 WC Physics, Multidisciplinary SC Physics GA 266LH UT WOS:000084301100022 ER PT J AU Edgell, DH Kim, JS Wong, SK Pardo, RC Vondrasek, R AF Edgell, D. H. Kim, J. S. Wong, S. K. Pardo, R. C. Vondrasek, R. TI Model of charge-state distributions for electron cyclotron resonance ion source plasmas SO PHYSICAL REVIEW SPECIAL TOPICS-ACCELERATORS AND BEAMS LA English DT Article AB A computer model for the ion charge-state distribution (CSD) in an electron cyclotron resonance ion source (ECRIS) plasma is presented that incorporates non-Maxwellian distribution functions, multiple atomic species, and ion confinement due to the ambipolar potential well that arises from confinement of the electron cyclotron resonance (ECR) heated electrons. Atomic processes incorporated into the model include multiple ionization and multiple charge exchange with rate coefficients calculated for non-Maxwellian electron distributions. The electron distribution function is calculated using a Fokker-Planck code with an ECR heating term. This eliminates the electron temperature as an arbitrary user input. The model produces results that are a good match to CSD data from the ANL-ECRII ECRIS. Extending the model to 1D axial will also allow the model to determine the plasma and electrostatic potential profiles, further eliminating arbitrary user input to the model. C1 [Edgell, D. H.; Kim, J. S.; Wong, S. K.] FARTECH Inc, San Diego, CA 92122 USA. [Pardo, R. C.; Vondrasek, R.] Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. RP Edgell, DH (reprint author), FARTECH Inc, 3146 Bunche Ave, San Diego, CA 92122 USA. EM edgell@far-tech.com FU U.S. DOE-SBIR Grant [DE-FG03-97ER82381]; U.S. Department of Energy, Nuclear Physics Division [W-31-109-ENG-38] FX The authors thank Dr. M. Rensink, Dr. B. Stallard, Dr. T. Rognlien, and Dr. L. LoDestro for their help with this work. The work at FARTECH was supported by the U.S. DOE-SBIR Grant No. DE-FG03-97ER82381. The work at Argonne National Laboratory was supported by the U.S. Department of Energy, Nuclear Physics Division, under Contract No. W-31-109-ENG-38. NR 14 TC 3 Z9 3 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-4402 J9 PHYS REV SPEC TOP-AC JI Phys. Rev. Spec. Top.-Accel. Beams PD DEC 20 PY 1999 VL 2 IS 12 AR 123502 PG 6 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA V38AX UT WOS:000209317400002 ER PT J AU Le Sage, GP Cowan, TE Fiorito, RB Rule, DW AF Le Sage, G. P. Cowan, T. E. Fiorito, R. B. Rule, D. W. TI Transverse phase space mapping of relativistic electron beams using optical transition radiation SO PHYSICAL REVIEW SPECIAL TOPICS-ACCELERATORS AND BEAMS LA English DT Article AB Optical transition radiation (OTR) has proven to be a versatile and effective diagnostic for measuring the profile, divergence, and emittance of relativistic electron beams with a wide range of parameters. Diagnosis of the divergence of modern high brightness beams is especially well suited to OTR interference (OTRI) techniques, where multiple dielectric or metal foils are used to generate a spatially coherent interference pattern. Theoretical analysis of measured OTR and OTRI patterns allows precise measurement of electron beam emittance characteristics. Here we describe an extension of this technique to allow mapping of divergence characteristics as a function of transverse coordinates within a measured beam. We present the first experimental analysis of the transverse phase space of an electron beam using all optical techniques. Comparing an optically masked portion of the beam to the entire beam, we measure different angular spread and average direction of the particles. Direct measurement of the phase-space ellipse tilt angle has been demonstrated using this optical masking technique. C1 [Le Sage, G. P.; Cowan, T. E.] Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. [Fiorito, R. B.] Catholic Univ Amer, Washington, DC 20064 USA. [Rule, D. W.] Naval Surface Warfare Ctr, Carderock Div, West Bethesda, MD 20817 USA. RP Le Sage, GP (reprint author), Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RI Cowan, Thomas/A-8713-2011 OI Cowan, Thomas/0000-0002-5845-000X FU U.S. Department of Energy by the Lawrence Livermore National Laboratory [W-7405-Eng-48] FX We would like to acknowledge the expert assistance of G. G. Anderson, R. P. Hall, and W. S. Patterson in fielding these experiments. This work was performed under the auspices of the U.S. Department of Energy by the Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48. NR 6 TC 8 Z9 8 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-4402 J9 PHYS REV SPEC TOP-AC JI Phys. Rev. Spec. Top.-Accel. Beams PD DEC 20 PY 1999 VL 2 IS 12 AR 122802 PG 7 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA V38AX UT WOS:000209317400001 ER PT J AU Alber, MS Camassa, R Fedorov, YN Holm, DD Marsden, JE AF Alber, MS Camassa, R Fedorov, YN Holm, DD Marsden, JE TI On billiard solutions of nonlinear PDEs SO PHYSICS LETTERS A LA English DT Article ID INTEGRABLE HAMILTONIAN SYSTEM; PEAKED SOLITONS; GEODESICS; EQUATION; PEAKONS; LATTICE; MATRIX AB This Letter presents some special features of a class of integrable PDEs admitting billiard-type solutions, which set them apart from equations whose solutions are smooth, such as the KdV equation. These billiard solutions are weak solutions that are piecewise smooth and have first derivative discontinuities at peaks in their profiles. A connection is established between the peak locations and finite dimensional billiard systems moving inside n-dimensional quadrics under the field of Hooke potentials. Points of reflection are described in terms of theta-functions and are shown to correspond to the location of peak discontinuities in the PDEs weak solutions. The dynamics of the peaks is described in the context of the algebraic-geometric approach to integrable systems. (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. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. Univ Notre Dame, Dept Math, Notre Dame, IN 46556 USA. Univ N Carolina, Dept Math, Chapel Hill, NC 27599 USA. Univ Politecn Catalunya, Dept Matemat 2, E-08027 Barcelona, Spain. CALTECH, Pasadena, CA 91125 USA. RP Alber, MS (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, MS B284, Los Alamos, NM 87545 USA. OI Holm, Darryl D/0000-0001-6362-9912 NR 29 TC 27 Z9 28 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD DEC 20 PY 1999 VL 264 IS 2-3 BP 171 EP 178 DI 10.1016/S0375-9601(99)00784-7 PG 8 WC Physics, Multidisciplinary SC Physics GA 274NT UT WOS:000084772500015 ER PT J AU Yi, SI Liang, Y Thevuthasan, S Chambers, SA AF Yi, SI Liang, Y Thevuthasan, S Chambers, SA TI Morphological and structural investigation of the early stages of epitaxial growth of alpha-Fe2O3 (0001) on alpha-Al2O3 (0001) by oxygen-plasma-assisted MBE SO SURFACE SCIENCE LA English DT Article DE buckling; corrundum; diffraction; epitaxy; hematite; MBE; plasma; sapphire ID MOLECULAR-BEAM EPITAXY; IRON-OXIDES; FILMS; PHOTOEMISSION; SPECTROSCOPY; FE3O4(111); SURFACES AB We have investigated the early stages of alpha-Fe2O3 (0001) film growth on alpha-Al2O3 (0001) using oxygen-plasma-enhanced molecular beam epitaxy along with reflection high-energy electron diffraction, non-contact atomic force microscopy, and X-ray photoelectron spectroscopy and diffraction. A compressionally strained, fully stoichiometric alpha-Fe2O3 film three monolayers thick forms prior to the onset of three-dimensional island formation and lattice relaxation. The surface of this film appears to buckle along (<11(2)over bar 0>), giving rise to a new set of inwardly contracted diffraction spots, which, if not resolved from the substrate spots, could be interpreted as a 12% in-plane lattice parameter expansion. Such an interpretation has led prior investigators to conclude that the interfacial layer consists of a disordered cation layer with an in-plane lattice parameter similar to 6% larger than that of alpha-Fe2Oa3 [T. Fujii, D. Alders, F.C. Voogt, T. Hibma, B.T. Thole, G.A. Sawatzky, Surf. Sci. 366 (1996) 579]. Our interpretation of the diffraction data suggests that the interfacial layer is badly distorted but commensurate with the substrate. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Chambers, SA (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. NR 25 TC 28 Z9 28 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD DEC 20 PY 1999 VL 443 IS 3 BP 212 EP 220 DI 10.1016/S0039-6028(99)00992-9 PG 9 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 265GE UT WOS:000084233300009 ER PT J AU Yencha, AJ King, GC Lopes, MCA Bozek, JD Berrah, N AF Yencha, AJ King, GC Lopes, MCA Bozek, JD Berrah, N TI Photo-double ionization of deuterium chloride studied by threshold photoelectrons coincidence spectroscopy SO CHEMICAL PHYSICS LETTERS LA English DT Article ID ENERGY RELEASE SPECTROSCOPY; CHARGED IONS; INFRARED-SPECTRUM; POTENTIAL CURVES; HCL2+; DICATION; CO2+; PREDISSOCIATION; DISSOCIATION; MOLECULES AB Photo-double ionization of DCl has been investigated in the 35.5-38 eV energy range using synchrotron radiation on beamline 10.0.1.2 of the Advanced Light Source by the threshold photoelectrons coincidence (TPEsCO) method. The TPEsCO spectrum of DCl, encompassing the formation of the ground (X (3)Sigma(-)) and first-excited (a (1)Delta) states of DCl2+, was recorded at good resolution (similar to 13 meV) using a pair of penetrating-field electron spectrometers. Four vibrational bands were identified in both electronic-state systems. In addition, the threshold photoelectron (TPE) spectrum of DCl for the formation of singly-charged DCl was recorded simultaneously in the same energy range. Indirect resonance autoionization of Rydberg ion states appears to play a substantial role in the formation of the (X (3)Sigma(-)) State of DCl2+ while the (a (1)Delta) state appears to be formed primarily by direct photo-double ionization. (C) 1999 Elsevier Science B.V. All rights reserved. C1 SUNY Albany, Dept Chem, Albany, NY 12222 USA. Univ Manchester, Schuster Lab, Dept Phys & Astron, Manchester M13 9PL, Lancs, England. Univ Fed Juiz de Fora, ICE, Dept Fis, BR-36036330 Juiz de Fora, MG, Brazil. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Western Michigan Univ, Dept Phys, Kalamazoo, MI 49008 USA. RP Yencha, AJ (reprint author), SUNY Albany, Dept Chem, Albany, NY 12222 USA. RI Bozek, John/E-4689-2010; Bozek, John/E-9260-2010 OI Bozek, John/0000-0001-7486-7238 NR 33 TC 21 Z9 21 U1 1 U2 5 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 DEC 17 PY 1999 VL 315 IS 1-2 BP 37 EP 42 DI 10.1016/S0009-2614(99)01226-9 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 266VX UT WOS:000084321900007 ER PT J AU Schultz, DL AF Schultz, DL TI Comparison of lipid levels during spawning in annual and perennial darters of the subgenus Boleosoma, Etheostoma perlongum, and Etheostoma olmstedi SO COPEIA LA English DT Article ID TROUT SALMO-TRUTTA; LIFE-HISTORY; LATITUDINAL VARIATION; ADAPTIVE SIGNIFICANCE; GAMBUSIA-HOLBROOKI; BODY-COMPOSITION; FAT-CONTENT; FISH; STRATEGIES; SURVIVAL AB Etheostoma perlongum, the Waccamaw darter, is an annual species, and most adults die soon after spawning. This study compared the body composition of the Waccamaw darter to a close relative, E. olmstedi, the tessellated darter, during the spawning season. Tessellated darters are perennial, some live three years. Lipid composition of both species was quantified as the proportion of the body that could be extracted in petroleum ether. Nonlipid composition was quantified as the residual of a regression of lean dry mass on standard length. Change in lipid and nonlipid composition was followed through the spawning season. Differences in body com position were consistent with life-history differences. Waccamaw darters had less lipid in their bodies through the spawning season and some depleted nonlipid material. Tessellated darters were more conservative of lipid and few depleted nonlipid material. At the same time that adult Waccamaw darters had highly depleted bodies, their young were in good condition. Adult Waccamaw darters appear to be actively allocating lipid and nonlipid material to reproduction rather than to maintenance or storage. Mean lipid levels in Waccamaw darters during spawning were comparable to lipid levels associated with death in other fish species. The conditions required for a semelparous annual life history and the conditions that select for an iteroparous life history are discussed relative to the habitat and biology of both species. C1 Univ Georgia, Savannah River Ecol Lab, Aiken, SC 29802 USA. RP Schultz, DL (reprint author), Nicholls State Univ, Dept Biol Sci, Thibodaux, LA 70310 USA. NR 42 TC 2 Z9 2 U1 0 U2 4 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 DEC 17 PY 1999 IS 4 BP 906 EP 916 PG 11 WC Zoology SC Zoology GA 269NH UT WOS:000084484100005 ER PT J AU Jones, IM Thomas, CB Haag, K Pleshanov, P Vorobstova, I Tureva, L Nelson, DO AF Jones, IM Thomas, CB Haag, K Pleshanov, P Vorobstova, I Tureva, L Nelson, DO TI Total gene deletions and mutant frequency of the HPRT gene as indicators of radiation exposure in Chernobyl liquidators SO MUTATION RESEARCH-FUNDAMENTAL AND MOLECULAR MECHANISMS OF MUTAGENESIS LA English DT Article DE Chernobyl; molecular; deletion; mutation; HPRT; radiation; human population ID ATOMIC-BOMB SURVIVORS; HUMAN LYMPHOCYTES-T; IONIZING-RADIATION; SOMATIC MUTATIONS; CLEANUP WORKERS; GLYCOPHORIN-A; MOLECULAR ANALYSIS; CANCER-PATIENTS; MULTIPLEX-PCR; CLONING ASSAY AB This study was conducted to determine the utility of deletion spectrum and mutant frequency (MF) of the hypoxanthine phosphoribosyl transferase gene (HPRT) as indicators of radiation exposure in Russian Liquidators who served in 1986 or 1987 in the clean up effort following the nuclear power plant accident at Chernobyl. HPRT MF was determined using the cloning assay for 117 Russian Controls and 122 Liquidators whose blood samples were obtained between 1991 and 1998. Only subjects from whom mutants were obtained for deletion analysis are included. Multiplex PCR analysis was performed on cell extracts of 1080 thioguanine resistant clones from Controls and 944 clones from Liquidators. Although the deletion spectra of Liquidators and Controls were similar overall, the Liquidator deletion spectrum was heterogeneous over time. Most notable, the proportion of total gene deletions was higher in 1991-1992 Liquidators than in Russian Controls (chi(2) = 10.5, p = 0.001) and in 1993-1994 Liquidators (chi(2) = 8.3, p = 0.004), and was marginally elevated relative to 1995-1996 Liquidators (chi(2) = 3.3, p = 0.07). This type of mutation has been highly associated with radiation exposure. Total gene deletions were not increased after 1992. Band shift mutations were also increased in the 1991-1992 Liquidators but were associated with increased MF of both Liquidators and Controls (p = 0.009), not with increased MF in 1991-1992 Liquidators (p = 0.7), and hence are not believed to be associated with radiation exposure. Regression analysis demonstrated that relative to Russian Controls HPRT MF was elevated in Liquidators overall when adjusted for age and smoking status (37%, p = 0.0001), and also was elevated in Liquidators sampled in 1991-1992 (72%. p = 0.0076), 1993-1994 (22%, p = 0.037), and 1995-1996 (62%, p = 0.0001). In summary, HPRT MF was found to be the more sensitive and persistent indicator of radiation exposure, but the specificity of total gene deletions red to detection of probable heterogeneity of radiation exposure within the exposed population. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94550 USA. Minist Hlth, Appl Ecol Res Lab, Moscow 113149, Russia. Minist Hlth, Cent Res Inst Roentgenol & Radiol, St Petersburg, Russia. Tula Diagnos Ctr, Tula, Russia. RP Jones, IM (reprint author), Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, L-452,Box 808, Livermore, CA 94550 USA. FU NCI NIH HHS [P01 CA59431] NR 49 TC 11 Z9 12 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0027-5107 J9 MUTAT RES-FUND MOL M JI Mutat. Res.-Fundam. Mol. Mech. Mutagen. PD DEC 17 PY 1999 VL 431 IS 2 BP 233 EP 246 DI 10.1016/S0027-5107(99)00166-9 PG 14 WC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology SC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology GA 270LY UT WOS:000084538200008 PM 10635990 ER PT J AU Walker, VE Jones, IM Crippen, TL Meng, QX Walker, DM Bauer, MJ Reilly, AA Tates, AD Nakamura, J Upton, PB Skopek, TR AF Walker, VE Jones, IM Crippen, TL Meng, QX Walker, DM Bauer, MJ Reilly, AA Tates, AD Nakamura, J Upton, PB Skopek, TR TI Relationships between exposure, cell loss and proliferation, and manifestation of Hprt mutant T cells following treatment of preweanling, weanling, and adult male mice with N-ethyl-N-nitrosourea SO MUTATION RESEARCH-FUNDAMENTAL AND MOLECULAR MECHANISMS OF MUTAGENESIS LA English DT Article DE ethylnitrosourea; Hprt; lymphocytes; mice; molecular dosimetry; mutagenicity ID LACI TRANSGENIC MICE; IN-VIVO; INHALATION EXPOSURE; 6-THIOGUANINE-RESISTANT LYMPHOCYTES; MOUSE LYMPHOCYTES; FISCHER-344 RATS; INVIVO EXPOSURE; B6C3F1 MICE; BONE-MARROW; F344 RATS AB Experiments were performed to characterize the age-related patterns of appearance and frequency of hypoxanthine-guanine phosphoribosyl transferase (Hprt) mutant T lymphocytes in thymus and spleen following exposure of preweanling (12-day-old), weanling (22-day-old), and young adult (8-week-old) male B6C3F1 mice to ethylnitrosourea (ENU). Mice were given single i.p. injections of 0 or 40 mg ENU/kg and then groups of animals were necropsied from 2 h to 116 days after treatment to examine the relationships between exposure, cell loss and proliferation, and the frequency of Hprt mutant T cells in thymus and spleen. Hprt mutant frequency (Mf) data for thymus of ENU-exposed (0, 11.7, 35, 58, or 72 mg/kg, or five weekly doses of 1.7 mg/kg i.p.) male C57BL/6 mice (12- or 62-week-old), obtained during an earlier study of spleen cells [I.M. Jones, K. Burkhart-Schultz, C.L. Strout, T.L. Crippen, Factors that affect the frequency of thioguanine-resistant lymphocytes in mice following exposure to ethylnitrosourea, Environ. Mutagen. 9 (1987) 317-329.], were compared to results in B6C3F1 mice. Isolated T cells were cultured in the presence of mitogen, growth factor, and 6-thioguanine to detect Hprt mutants. The time required to achieve maximum Mfs in thymus was uniformly found at 2 weeks after ENU treatment, while the times needed to reach peak values in spleen were proportional to animal age at treatment. These data indicate that age-related differences in the appearance of Hprt mutant cells in spleen are largely defined by the physiologically based, age-dependent trafficking of mutant cells from or through the thymus. Three modes of handling the resulting Hprt MS data were evaluated: (i) comparing the Mfs at a single time point, (ii) comparing the maximum Mfs observed. and (iii) comparing the change in Mfs over time (or the mutant T cell 'manifestation' curves in treated vs. control mice) in each age group post-exposure. Measuring the Mfs in spleen at multiple time points after cessation of exposure and integrating the frequency of mutants as a function of time appeared to be the superior method for comparing mutagenic responses in different age groups. Some of the underlying assumptions of this approach, as well as its strengths and weaknesses, are discussed. (C) 1999 Elsevier Science B.V. All rights reserved. C1 New York State Dept Hlth, Wadsworth Ctr Labs & Res, Albany, NY 12201 USA. Univ N Carolina, Dept Environm Sci & Engn, Chapel Hill, NC 27599 USA. SUNY Albany, Sch Publ Hlth, Albany, NY 12203 USA. Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94550 USA. Leiden Univ, Med Ctr, Dept Radiat Genet & Chem Mutagenesis, NL-2300 RA Leiden, Netherlands. Univ N Carolina, Dept Pathol, Chapel Hill, NC 27599 USA. RP Walker, VE (reprint author), New York State Dept Hlth, Wadsworth Ctr Labs & Res, Albany, NY 12201 USA. FU NCI NIH HHS [CA33648-01A1]; NICHD NIH HHS [1R01 HD]; NIEHS NIH HHS [P42-ES0594801] NR 40 TC 28 Z9 29 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0027-5107 J9 MUTAT RES-FUND MOL M JI Mutat. Res.-Fundam. Mol. Mech. Mutagen. PD DEC 17 PY 1999 VL 431 IS 2 BP 371 EP 388 DI 10.1016/S0027-5107(99)00180-3 PG 18 WC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology SC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology GA 270LY UT WOS:000084538200020 PM 10636002 ER PT J AU Miller, MK AF Miller, MK TI Materials science - Imaging elusive solute atoms SO SCIENCE LA English DT Editorial Material ID PROBE C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Miller, MK (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. NR 11 TC 9 Z9 9 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 DEC 17 PY 1999 VL 286 IS 5448 BP 2285 EP 2286 DI 10.1126/science.286.5448.2285 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 266UK UT WOS:000084318500038 ER PT J AU Mora, CI Riciputi, LR Cole, DR AF Mora, CI Riciputi, LR Cole, DR TI Short-lived oxygen diffusion during hot, deep-seated meteoric alteration of anorthosite SO SCIENCE LA English DT Article ID REGIONAL METAMORPHISM; HYDROTHERMAL SYSTEMS; WATER FUGACITY; ION MICROPROBE; ISOTOPE RATIOS; STABLE-ISOTOPE; NEW-ZEALAND; IDAHO; EQUILIBRIA; BATHOLITH AB Heterogeneous oxygen isotope compositions of plagioclase from the Boehls Butte anorthosite include some of the most oxygen-18-depleted values (to -16 per mil) reported for plagioclase in meta-igneous rocks and indicate high-temperature (T > 500 degrees C) isotopic exchange between plagioclase and nearly pristine meteoric fluid. Retrograde reaction-enhanced permeability assisted influx of meteoric-hydrothermal fluids into the deep-seated anorthosite. Isotopic gradients of about 14 per mil over 600 micrometers in single crystals require short-lived (about 10(4) years) diffusional exchange of oxygen and Locally Large effective water:rock ratios, followed by rapid Loss of water and cessation of oxygen diffusion in the anorthosite. C1 Univ Tennessee, Dept Geol Sci, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Mora, CI (reprint author), Univ Tennessee, Dept Geol Sci, Knoxville, TN 37996 USA. RI Mora, Claudia/B-5511-2017 OI Mora, Claudia/0000-0003-2042-0208 NR 27 TC 10 Z9 10 U1 2 U2 5 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 DEC 17 PY 1999 VL 286 IS 5448 BP 2323 EP 2325 DI 10.1126/science.286.5448.2323 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 266UK UT WOS:000084318500055 ER PT J AU McKamey, CG George, EP Lee, EH Ohriner, EK Heatherly, L Cohron, JW AF McKamey, CG George, EP Lee, EH Ohriner, EK Heatherly, L Cohron, JW TI Impurity effects on high-temperature tensile ductility of iridium alloys at high strain rate SO SCRIPTA MATERIALIA LA English DT Article DE iridium alloys; impurity effects; tensile properties C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP McKamey, CG (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. RI George, Easo/L-5434-2014 NR 17 TC 3 Z9 3 U1 0 U2 5 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 DEC 17 PY 1999 VL 42 IS 1 BP 9 EP 15 DI 10.1016/S1359-6462(99)00339-5 PG 7 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 273PM UT WOS:000084716100003 ER PT J AU Clausen, B Leffers, T Lorentzen, T Pedersen, OB Van Houtte, P AF Clausen, B Leffers, T Lorentzen, T Pedersen, OB Van Houtte, P TI The resolved shear stress on the non-active slip systems in Taylor/Bishop-Hill models for fcc polycrystals SO SCRIPTA MATERIALIA LA English DT Article DE theory and modelling; mechanical properties; constitutive equations; crystal structure; resolved shear stress C1 Riso Natl Lab, Mat Res Dept, DK-4000 Roskilde, Denmark. Katholieke Univ Leuven, Dept MTM, B-3001 Heverlee, Belgium. RP Clausen, B (reprint author), Univ Calif Los Alamos Natl Lab, Mail Stop H805, Los Alamos, NM 87545 USA. RI Clausen, Bjorn/B-3618-2015 OI Clausen, Bjorn/0000-0003-3906-846X NR 11 TC 1 Z9 1 U1 1 U2 3 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 DEC 17 PY 1999 VL 42 IS 1 BP 91 EP 96 DI 10.1016/S1359-6462(99)00318-8 PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 273PM UT WOS:000084716100015 ER PT J AU Ayotte, P Nielsen, SB Weddle, GH Johnson, MA Xantheas, SS AF Ayotte, P Nielsen, SB Weddle, GH Johnson, MA Xantheas, SS TI Spectroscopic observation of ion-induced water dimer dissociation in the X-center dot(H2O)(2) (X = F, Cl, Br, I) clusters SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Letter ID CORRELATED MOLECULAR CALCULATIONS; GAUSSIAN-BASIS SETS; GAS-PHASE; VIBRATIONAL SPECTROSCOPY; HYDROGEN-BOND; ENERGETICS; ARGON; MICROCLUSTERS; CL-(H2O)(N); ASSOCIATION AB We elucidate the interplay between the ion-water and water-water interactions in determining the structures of halide ion-water clusters using infrared spectroscopy, interpreted with ab initio theory. Vibrational predissociation spectra of the X-.(H2O)(2). Ar-m (X = F, Cl, Br, I) clusters in the OH stretching region (2300-3800 cm(-1)) reveal a strongly halide-dependent pattern of bands. These spectra encode the incremental weakening of the interaction between the water molecules with the lighter halides, finally leading to their complete dissociation in the fluoride complex. A consequence of this is that the F-.(H2O)(2) cluster is likely to be a floppy system with high amplitude zero point motion, in contrast to the pseudo-rigid behavior of the other halide hydrates. C1 Yale Univ, Sterling Chem Lab, New Haven, CT 06520 USA. Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Johnson, MA (reprint author), Yale Univ, Sterling Chem Lab, POB 208107, New Haven, CT 06520 USA. RI Xantheas, Sotiris/L-1239-2015; Brondsted Nielsen, Steen/G-5844-2016 NR 42 TC 114 Z9 114 U1 1 U2 10 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 DEC 16 PY 1999 VL 103 IS 50 BP 10665 EP 10669 DI 10.1021/jp991963r PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 268PP UT WOS:000084425000001 ER PT J AU Schulz, JC Warr, GG Hamilton, WA Butler, PD AF Schulz, JC Warr, GG Hamilton, WA Butler, PD TI A new model for neutron reflectometry of adsorbed surfactant aggregates SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID SILICA-WATER INTERFACE; SOLID-LIQUID INTERFACES; NONIONIC SURFACTANTS; CETYLTRIMETHYLAMMONIUM BROMIDE; CATIONIC SURFACTANTS; AQUEOUS-SOLUTION; MICELLAR SOLUTIONS; COLLOIDAL SILICA; X-RAY; ADSORPTION AB A new interpretation of neutron reflectivity data for surfactants adsorbed on hydrophilic solid surfaces has been developed. Motivated by recent atomic force microscopy results, a model of the adsorbed layer is constructed based upon an adsorbed layer consisting of discrete, micelle-like surfactant aggregates of well-defined geometries. Scattering length density profiles and reflectivity curves are calculated for conventional, laterally unstructured adsorbed layers (a bilayer), as well as for cylindrical and spherical surfactant aggregates adsorbed on a hydrophilic surface. It is shown that treating such structured surfactant films as bilayers often results in a good fit to neutron reflectivity data, but that fit parameters lead one to underestimate the film thickness and overestimate the fractional surface coverage by the adsorbed film. C1 Univ Sydney, Sch Chem, Sydney, NSW 2006, Australia. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Warr, GG (reprint author), Univ Sydney, Sch Chem, Sydney, NSW 2006, Australia. RI Schulz, Jamie/B-3819-2008; Butler, Paul/D-7368-2011 NR 62 TC 16 Z9 16 U1 0 U2 4 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 DEC 16 PY 1999 VL 103 IS 50 BP 11057 EP 11063 DI 10.1021/jp990827j PG 7 WC Chemistry, Physical SC Chemistry GA 268PJ UT WOS:000084424500012 ER PT J AU Miyabe, K Guiochon, G AF Miyabe, K Guiochon, G TI Thermodynamic characteristics of surface diffusion in reversed-phase liquid chromatography SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID OCTADECYLSILYL-SILICA GEL; BONDED PHASES; ADSORPTION CHARACTERISTICS; LATERAL DIFFUSION; ACTIVATED CARBON; PERFORMANCE; DEPENDENCE; PACKINGS; TEMPERATURE; INTERFACE AB The thermodynamic properties of surface diffusion in reversed-phase liquid chromatography (RPLC) were analyzed in connection with the thermodynamics of surface diffusion;in gas chromatography systems and of phase equilibrium in RPLC. The results suggest that the activation energy of surface diffusion in RPLC consists of only two contributions, corresponding to a hole-making and a bend-breaking process. The former is dose to the activation energy of the mobile phase viscosity; the latter is correlated with the isosteric heat of adsorption (Q(st)), by a numerical coefficient between 0.5 and 0.6. The validity of these results was proved by the analysis of correlations between the surface diffusion coefficient (D-s) and the adsorption equilibrium constant (linear free energy relation), between D-s and the boiling point of the sample components, and between the ratio of D-s to the molecular diffusivity and Q(st). These results support a restricted diffusion model, proposed earlier as an approximation of the mass transfer mechanism of surface diffusion. The restricted diffusion model provides consistent interpretations for the intrinsic thermodynamic properties of surface diffusion in RPLC. C1 Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Guiochon, G (reprint author), Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. NR 48 TC 46 Z9 46 U1 0 U2 2 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 DEC 16 PY 1999 VL 103 IS 50 BP 11086 EP 11097 DI 10.1021/jp991725w PG 12 WC Chemistry, Physical SC Chemistry GA 268PJ UT WOS:000084424500016 ER PT J AU Brown, DA Wang, FQ Danielewicz, P AF Brown, DA Wang, FQ Danielewicz, P TI Implications of the unusual structure in the pp correlation from Pb plus Pb collisions at 158 AGeV SO PHYSICS LETTERS B LA English DT Article ID HEAVY-ION REACTIONS AB The recent NA49 measurement of two-proton correlation function shows an interesting and unexpected structure at large relative momentum. Applying source imaging techniques to the measurement, we find an unusually steep drop-off in the two-proton source function. We show that the steep drop-off is due to the structure in the correlation and the drop-off cannot be explained using conventional correlation analysis. We suggest possible physics reasons for the unusual source function. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Washington, Inst Nucl Theory, Seattle, WA 98195 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Michigan State Univ, Natl Superconducting Cyclotron Lab, E Lansing, MI 48824 USA. Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. RP Brown, DA (reprint author), Univ Washington, Inst Nucl Theory, Box 351550, Seattle, WA 98195 USA. NR 17 TC 7 Z9 8 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 DEC 16 PY 1999 VL 470 IS 1-4 BP 33 EP 38 DI 10.1016/S0370-2693(99)01293-9 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 268BH UT WOS:000084394100006 ER PT J AU Barkhuff, DH Armstrong, CS Bertozzi, W Chen, JP Dale, D Dodson, G Dow, KA Epstein, MB Farkhondeh, M Finn, JM Gilad, S Jones, MK Joo, K Kelly, JJ Kowalski, S Liu, D Lourie, RW McIntyre, JI Madey, R Margaziotis, DJ Markowitz, P Mertz, C Milbrath, BD Mitchell, J Mukhopadhyay, S Perdrisat, CF Punjabi, V Qin, L Rutt, PM Sarty, AJ Tieger, D Tschalaer, C Turchinetz, W Ulmer, PE Van Verst, SP Vellidis, C Warren, G Weinstein, LB Woo, RJ AF Barkhuff, DH Armstrong, CS Bertozzi, W Chen, JP Dale, D Dodson, G Dow, KA Epstein, MB Farkhondeh, M Finn, JM Gilad, S Jones, MK Joo, K Kelly, JJ Kowalski, S Liu, D Lourie, RW McIntyre, JI Madey, R Margaziotis, DJ Markowitz, P Mertz, C Milbrath, BD Mitchell, J Mukhopadhyay, S Perdrisat, CF Punjabi, V Qin, L Rutt, PM Sarty, AJ Tieger, D Tschalaer, C Turchinetz, W Ulmer, PE Van Verst, SP Vellidis, C Warren, G Weinstein, LB Woo, RJ TI Measurement of recoil proton polarizations in the electrodisintegration of deuterium by polarized electrons SO PHYSICS LETTERS B LA English DT Article ID ANALYZING POWER; SCATTERING; NUCLEI; OBSERVABLES AB In order to test modem theories of two-nucleon bound and scattering states, we have measured the spin polarization of ejectile protons in the electrodisintegration reaction d((e) over right arrow, e'(p) over right arrow)n. Compared with spin-averaged observations, these observables offer the potential of enhanced sensitivity to details of the reaction process. The experiment was carried out in quasielastic kinematics (q(mu)q(mu)= -2m(p) omega= -0.38GeV(2)/c(2)). Protons were detected at two angles corresponding to neutron recoil momenta p(r) of 0 and 100MeV/c. Full nonrelativistic calculations of the polarization transfer components s(l) and s(t), including leading order relativistic contributions, describe our measurements well, but calculations of the induced polarization s(n) at p(r) = 100 MeV/c underpredict the experimental result. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 MIT, Cambridge, MA 02139 USA. Univ Virginia, Charlottesville, VA 22901 USA. Coll William & Mary, Williamsburg, VA 23187 USA. Calif State Univ Los Angeles, Los Angeles, CA 90032 USA. Univ Maryland, College Pk, MD 20742 USA. Kent State Univ, Kent, OH 44242 USA. Arizona State Univ, Tempe, AZ 85281 USA. Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. Norfolk State Unif, Norfolk, VA 23504 USA. Old Dominion Univ, Norfolk, VA 23529 USA. Rutgers State Univ, Piscataway, NJ 08855 USA. Univ Athens, Athens, Greece. RP Barkhuff, DH (reprint author), MIT, 77 Massachusetts Ave, Cambridge, MA 02139 USA. RI Sarty, Adam/G-2948-2014; McIntyre, Justin/P-1346-2014 OI McIntyre, Justin/0000-0002-3706-4310 NR 23 TC 11 Z9 11 U1 0 U2 2 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 DEC 16 PY 1999 VL 470 IS 1-4 BP 39 EP 44 DI 10.1016/S0370-2693(99)01294-0 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 268BH UT WOS:000084394100007 ER PT J AU Henry, MR Stevens, PW Sun, J Kelso, DM AF Henry, MR Stevens, PW Sun, J Kelso, DM TI Real-time measurements of DNA hybridization on microparticles with fluorescence resonance energy transfer SO ANALYTICAL BIOCHEMISTRY LA English DT Article ID BIOMOLECULAR INTERACTION ANALYSIS; NUCLEIC-ACID HYBRIDIZATION; SURFACE-PLASMON RESONANCE; COATED POLYSTYRENE LATEX; OLIGONUCLEOTIDE ARRAYS; SANDWICH HYBRIDIZATION; OPTICAL BIOSENSOR; BINDING-KINETICS; BIOTINYLATED DNA; POLYNUCLEOTIDES AB When capture oligonucleotides are tethered on planar surfaces, mass transport limitations influence the kinetics of solid-phase nucleic acid hybridizations. By diffusion theory, however, hybridization of oligonucleotides on microparticles should be reaction-rate limited. In an initial effort to understand the kinetics of microparticle hybridization reactions, we developed a fluorescence resonance energy transfer method for monitoring oligonucleotide hybridization on microparticles. Microparticles were coated with a fluoresceinated oligomer at surface densities of 20, 40, and 80% saturation, hybridized to a complementary oligonucleotide labeled with tetramethylrhodamine, and monitored over time for quenching of the fluorescein signal as hybridization occurred on the particle surface. Association rate constants were compared for microparticle-based hybridization and solution-phase hybridization. Rate constants for hybridizations on the particle surface were about an order of magnitude less than those for hybridization in solution, but decreasing the surface density of the capture oligonucleotide to 20% saturation improved particle hybridization rates. Although a bimolecular reaction model adequately described solution-phase hybridization kinetics, oligonucleotide hybridization on microparticles did not fit this model but exhibited biphasic reaction kinetics. Based on two different lines of reasoning, we argue that microparticle-based oligonucleotide hybridization was indeed reaction-rate limited in our system and not diffusion-rate Limited. (C) 1999 Academic Press. C1 Northwestern Univ, Robert R McCormick Sch Engn & Appl Sci, Dept Biomed Engn, Evanston, IL 60208 USA. Argonne Natl Lab, Biosci Div, Argonne, IL 60439 USA. RP Henry, MR (reprint author), Northwestern Univ, Robert R McCormick Sch Engn & Appl Sci, Dept Biomed Engn, 2145 Sheridan Rd, Evanston, IL 60208 USA. EM mrh244@nwu.edu RI Kelso, David/B-7619-2009; Kelso, David/F-5622-2013 NR 57 TC 98 Z9 99 U1 1 U2 17 PU ACADEMIC PRESS INC ELSEVIER SCIENCE 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 DEC 15 PY 1999 VL 276 IS 2 BP 204 EP 214 DI 10.1006/abio.1999.4344 PG 11 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 266DC UT WOS:000084284500013 PM 10603244 ER PT J AU Yan, XM Grace, WK Yoshida, TM Habbersett, RC Velappan, N Jett, JH Keller, RA Marrone, BL AF Yan, XM Grace, WK Yoshida, TM Habbersett, RC Velappan, N Jett, JH Keller, RA Marrone, BL TI Characteristics of different nucleic acid staining dyes for DNA fragment sizing by flow cytometry SO ANALYTICAL CHEMISTRY LA English DT Article ID DOUBLE-STRANDED DNA; THIAZOLE ORANGE-DYE; PHOTOPHYSICAL PROPERTIES; FLUORESCENCE DETECTION; BIS-INTERCALATION; CYANINE DYES; SENSITIVITY; MOLECULES; BINDING; YOYO AB An efficient and reliable double-stranded DNA (dsDNA) staining protocol for DNA fragment sizing by flow cytometry is presented, The protocol employs 0.8 phl of PicoGreen to label a dde range of DNA concentrations (0.5 ng/mL to 10000 ng/mL) without regard to the solution dye/bp ratios and without initial quantification of the DNA analyte concentration. Using a combination of spectrofluorometry and flow cytometry experiments, we found that PicoGreen exhibited better overall performance than all the tested dsDNA binding dyes, such as TOTO-1. Fluorometric titration revealed that typical DNA staining protocols designed on the basis of the dye/bp ratio were highly dependent upon the DNA concentration for optimal results. PicoGreen was the least sensitive to the solution dye/bp ratio and was highly fluorescent in the presence of dsDNA. Using this new protocol, accurate histograms of HindIII digested lambda. DNA were demonstrated for DNA concentrations ranging from 5 to 2000 ng/mL, and for dye/bp ratios from 106:1 to 1:4 at 0.8 mu M of PicoGreen. The new one-step protocol is broadly applicable to any sensitive, laser-induced fluorescence method for detection of nucleic acids. C1 Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Marrone, BL (reprint author), Univ Calif Los Alamos Natl Lab, Div Life Sci, MS M888, Los Alamos, NM 87545 USA. FU OCPHP CDC HHS [PR-01315] NR 40 TC 48 Z9 49 U1 2 U2 14 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 DEC 15 PY 1999 VL 71 IS 24 BP 5470 EP 5480 DI 10.1021/ac990780y PG 11 WC Chemistry, Analytical SC Chemistry GA 265MV UT WOS:000084248700004 PM 10624155 ER PT J AU Griffiths, SK Nilson, RH AF Griffiths, SK Nilson, RH TI Hydrodynamic dispersion of a neutral nonreacting solute in electroosmotic flow SO ANALYTICAL CHEMISTRY LA English DT Article AB Analytical methods are employed to determine the axial dispersion of a neutral nonreacting solute in an incompressible electroosmotic flow. In contrast to previous approaches, the dispersion is obtained here by solving the time-dependent diffusion-advection equation in transformed spatial and temporal coordinates to obtain the two-dimensional late-time concentration field. The coefficient of dispersion arises as a separation eigenvalue, and its value is obtained as a necessary condition for satisfying all of the required boundary conditions. Solutions based on the Debye-Huckel approximation are presented for both a circular tube and a channel of infinite width. These results recover the well-known solutions for dispersion in pressure-driven flows when the Debye length is very large, In this limit, the axial dispersion is proportional to the square of the Peclet number based on the characteristic transverse dimension of the tube or channel, In the limit of very small Debye lengths, we find that the dispersion varies as the square of the Peclet number based on the Debye length, Simple approximations to the coefficient of dispersion as functions of the Debye length and Peclet number are also presented. C1 Sandia Natl Labs, Livermore, CA 94551 USA. RP Griffiths, SK (reprint author), Sandia Natl Labs, Livermore, CA 94551 USA. NR 5 TC 69 Z9 69 U1 1 U2 4 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 DEC 15 PY 1999 VL 71 IS 24 BP 5522 EP 5529 DI 10.1021/ac990714w PG 8 WC Chemistry, Analytical SC Chemistry GA 265MV UT WOS:000084248700010 ER PT J AU Willig, TN Draptchinskaia, N Dianzani, I Ball, S Niemeyer, C Ramenghi, U Orfali, K Gustavsson, P Garelli, E Brusco, A Tiemann, C Perignon, JL Bouchier, C Cicchiello, L Dahl, N Mohandas, N Tchernia, G AF Willig, TN Draptchinskaia, N Dianzani, I Ball, S Niemeyer, C Ramenghi, U Orfali, K Gustavsson, P Garelli, E Brusco, A Tiemann, C Perignon, JL Bouchier, C Cicchiello, L Dahl, N Mohandas, N Tchernia, G TI Mutations in ribosomal protein S19 gene and Diamond Blackfan anemia: Wide variations in phenotypic expression SO BLOOD LA English DT Article ID ADENOSINE-DEAMINASE; CHROMOSOME 19Q13; KIT GENES; C-KIT; PROGENITORS; SEQUENCE; DNA AB Mutations of the ribosomal protein S19 (RPS19) gene were recently identified in 10 patients with Diamond Blackfan anemia (DBA). To determine the prevalence of mutations in this gene in DBA and to begin to define the molecular basis for the observed variable clinical phenotype of this disorder, the genomic sequence of the 6 exons and the 5' untranslated region of the RPS19 gene was directly assessed in DBA index cases from 172 new families. Mutations affecting the coding sequence of RPS19 or splice sites were found in 34 cases (19.7%), whereas mutations in noncoding regions were found in 8 patients (4.6%). Mutations included nonsense, missense, splice sites, and frameshift mutations. A hot spot for missense mutations was identified between codons 52 and 62 of the RPS19 gene in a new sequence consensus motif W-[YFW][YF]-x-R-[AT]-A-[SA]-x-[AL]-R-[HRK]-[ILV]-Y. No correlation between the nature of mutations and the different patterns of clinical expression, including age at presentation, presence of malformations, and therapeutic outcome, could be documented. Moreover, RPS19 mutations were also found in some first-degree relatives presenting only with isolated high erythrocyte adenosine deaminase activity and/or macrocytosis. The lack of a consistent relationship between the nature of the mutations and the clinical phenotype implies that yet unidentified factors modulate the phenotypic expression of the primary genetic defect in families with RPS19 mutations. (C) 1999 by The American Society of Hematology. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Univ Paris 11, Hop Bicetre, Dept Pediat, Assistance Publ Hop Paris, Bicetre, France. Univ Paris 11, Hop Bicetre, Hematol Lab, Assistance Publ Hop Paris, Bicetre, France. Univ Paris 11, Fac Med Paris Sud, Bicetre, France. Uppsala Univ, Childrens Hosp, Dept Genet & Pathol, Clin Genet Unit, Uppsala, Sweden. Univ Turin, Dept Pediat, I-10124 Turin, Italy. Univ Turin, Dept Genet, I-10124 Turin, Italy. Univ Eastern Piedmont, Dept Med Sci, Novara, Italy. St George Hosp, Sch Med, Dept Cellular & Mol Sci, DBA Study Grp,Div Haematol, London, England. Univ Freiburg, Kinderklin, D-7800 Freiburg, Germany. Hop Necker Enfants Malad, Assistance Publ Hop Paris, Biochim Lab, Paris, France. Banque ADN, Genethon 3, Evry, France. RP Willig, TN (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Mail Stop 74-217,1 Cyclotron Rd, Berkeley, CA 94720 USA. RI Brugnara, Carlo/A-8041-2010; Brusco, Alfredo/A-1811-2013 OI Brugnara, Carlo/0000-0001-8192-8713; Brusco, Alfredo/0000-0002-8318-7231 FU NIDDK NIH HHS [DK26263, DK32094]; Telethon [E.0619] NR 37 TC 136 Z9 140 U1 0 U2 3 PU AMER SOC HEMATOLOGY PI WASHINGTON PA 1200 19TH ST, NW, STE 300, WASHINGTON, DC 20036-2422 USA SN 0006-4971 J9 BLOOD JI Blood PD DEC 15 PY 1999 VL 94 IS 12 BP 4294 EP 4306 PG 13 WC Hematology SC Hematology GA 263TD UT WOS:000084140600036 PM 10590074 ER PT J AU Spancake, KM Anderson, CB Weaver, VM Matsunami, N Bissell, MJ White, RL AF Spancake, KM Anderson, CB Weaver, VM Matsunami, N Bissell, MJ White, RL TI E7-transduced human breast epithelial cells show partial differentiation in three-dimensional culture SO CANCER RESEARCH LA English DT Article ID RETINOBLASTOMA PROTEIN; BASEMENT-MEMBRANE; GENE-EXPRESSION; E7; CARCINOMA; CANCER; MOUSE; IMMORTALIZATION; FAMILY; CYCLE AB Disruption of the retinoblastoma (RB) tumor suppressor pathway is a common and important event in breast carcinogenesis, To examine the role of the retinoblastoma protein (pRB) in this process, we created human mammary epithelial cells (HMEC) deficient for pRB by infecting primary outgrowth from breast organoids with the human papillomavirus type 16 (HPV16) E7 gene, HPV16 E7 binds to and inactivates pRB and also causes a significant down-regulation of the protein. Culturing normal HMEC in a reconstituted basement membrane (rBM) provides a correct environment and signaling cues for the formation of differentiated, acinilike structures, When cultured in this rBM, HMEC+E7 were found to respond morphologically as normal HMEC and form acinar structures. In contrast to normal HMEC, many of the cells within the HMEC+E7 structures were not growth arrested, as determined by a 5-bromo-2'-deoxyuridine incorporation assay. pRB deficiency did not affect polarization of these structures, as indicated by the normal localization of the cell-cell adhesion marker E-cadherin and the basal deposition of a collagen IV membrane, However, in HMEC+E7 acini, we were unable to detect by immunofluorescence microscopy the milk protein lactoferrin or cytokeratin 19, both markers of differentiation expressed in the normal HMEC structures, These data suggest that loss of RB in vivo would compromise differentiation, predisposing these cells to future tumor-promoting actions. C1 Univ Utah, Huntsman Canc Inst, Salt Lake City, UT 84112 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Spancake, KM (reprint author), Univ Utah, Huntsman Canc Inst, 2000 Circle Hope,Bldg 555,Room 567B, Salt Lake City, UT 84112 USA. NR 26 TC 28 Z9 28 U1 0 U2 0 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 DEC 15 PY 1999 VL 59 IS 24 BP 6042 EP 6045 PG 4 WC Oncology SC Oncology GA 270HT UT WOS:000084530400006 PM 10626787 ER PT J AU Gonzalez-Leon, A Merdink, JL Bull, RJ Schultz, IR AF Gonzalez-Leon, A Merdink, JL Bull, RJ Schultz, IR TI Effect of pre-treatment with dichloroacetic or trichloroacetic acid in drinking water on the pharmacokinetics of a subsequent challenge dose in B6C3F1 mice SO CHEMICO-BIOLOGICAL INTERACTIONS LA English DT Article DE pre-treatment; dichloroacetic or trichloroacetic acid; drinking water ID TRICHLOROETHYLENE; METABOLISM; RATS; BIOTRANSFORMATION; CARCINOGENICITY; LIVER; MOUSE AB Dichloroacetate (DCA) and trichloroacetate (TCA) are prominent by-products of chlorination of drinking water. Both chemicals have been shown to be hepatic carcinogens in mice. Prior work has demonstrated that DCA inhibits its own metabolism in rats and humans. This study focuses on the effect of prior administration of DCA or TCA in drinking water on the pharmacokinetics of a subsequent challenge dose of DCA or TCA in male B6C3F1 mice. Mice were provided with DCA or TCA in their drinking water at 2 g/l for 14 days and then challenged with a 100 mg/kg i.v. (non-labeled) or gavage (C-14-labeled) dose of DCA or TCA. The challenge dose was administered after 16 h fasting and removal of the haloacetate pre-treatment. The haloacetate blood concentration-time profile and the disposition of C-14 were characterized and compared with controls. The effect of pre-treatment on the in vitro metabolism of DCA in hepatic S9 was also evaluated. Pre-treatment with DCA caused a significant increase in the blood concentration-time profiles of the challenge dose of DCA. No effect on the blood concentration-time profile of DCA was observed after pre-treatment with TCA. Pre-treatment with TCA had no effect on subsequent doses of DCA. Pre-treatment with DCA did not have a significant effect on the formation of (CO2)-C-14 from radiolabeled DCA. In vitro experiments with liver S9 from DCA-pre-treated mice demonstrated that DCA inhibits it own metabolism. These results indicate that DCA metabolism in mice is also susceptible to inhibition by prior treatment with DCA, however the impact on clearance is less marked in mice than in F344 rats. In contrast, the metabolism and pharmacokinetics of TCA is not affected by pre-treatment with either DCA or TCA. (C) Published by 1999 Elsevier Science Ireland Ltd. All rights reserved. C1 Battelle, Pacific NW Div, Mol Biosci Dept, Richland, WA 99352 USA. Washington State Univ, Pharmacol Toxicol Grad Program, Pullman, WA 99164 USA. RP Schultz, IR (reprint author), Battelle, Pacific NW Div, Mol Biosci Dept, POB 999 P7-56, Richland, WA 99352 USA. NR 21 TC 19 Z9 19 U1 0 U2 1 PU ELSEVIER SCI IRELAND LTD PI CLARE PA CUSTOMER RELATIONS MANAGER, BAY 15, SHANNON INDUSTRIAL ESTATE CO, CLARE, IRELAND SN 0009-2797 J9 CHEM-BIOL INTERACT JI Chem.-Biol. Interact. PD DEC 15 PY 1999 VL 123 IS 3 BP 239 EP 253 DI 10.1016/S0009-2797(99)00140-4 PG 15 WC Biochemistry & Molecular Biology; Pharmacology & Pharmacy; Toxicology SC Biochemistry & Molecular Biology; Pharmacology & Pharmacy; Toxicology GA 273TA UT WOS:000084722400004 PM 10654841 ER PT J AU Kaszuba, JP Runde, WH AF Kaszuba, JP Runde, WH TI The aqueous geochemistry of neptunium: Dynamic control of soluble concentrations with applications to nuclear waste disposal SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID CARBONATE COMPLEXES; SOLUBILITY; NP(V); EQUILIBRIA; HYDROLYSIS; CHEMISTRY; ION; DIOXONEPTUNIUM(V); COPRECIPITATION; 1000-DEGREES-C AB The valence state of neptunium, one of the most important radionuclides of concern for long-term emplacement of nuclear waste, primarily defines its geochemical reactions and migration behavior. We evaluate how redox potential and solid-phase stability interact and influence neptunium solubility and aqueous speciation in natural systems. Neptunium thermodynamic data for the most important valence states for natural waters, +IV and +V, are updated to correct database inconsistencies. The most significant changes are as follows: (1) Np2O5(cr) is 2 orders of magnitude more stable than reported previously, (2) the stability of NpO2OH(aq) is reduced, (3) NpO2(OH)(2)(-) and mixed Np(V) hydroxo-carbonato species become important at high pH, and (4) Np(OH)(5)(-) is disregarded as a valid species. As a result, NP2O5 and Np(OH)(4)(am) are the stable solids in aquifers of low ionic strength, neptunium solubility decreases in the pH range 10-12 and increases at pH above 12, and both redox potential and Np(OH)(4)(am) solubility product control soluble neptunium Concentrations at neutral pH and Eh between -0.2 and 0.3. These relationships are important for effective nuclear waste package design, such as including cement as an engineered barrier and evaluating impacts of discharged solutions on natural waters in release scenarios at nuclear waste storage facilities. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Runde, WH (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, CST-7,Mail Stop J514, Los Alamos, NM 87545 USA. NR 88 TC 101 Z9 103 U1 6 U2 44 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 DEC 15 PY 1999 VL 33 IS 24 BP 4427 EP 4433 DI 10.1021/es990470x PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 265PJ UT WOS:000084252300012 ER PT J AU Shannon, M Lamerdin, JE Richardson, L McCutchen-Maloney, SL Hwang, MH Handel, MA Stubbs, L Thelen, MP AF Shannon, M Lamerdin, JE Richardson, L McCutchen-Maloney, SL Hwang, MH Handel, MA Stubbs, L Thelen, MP TI Characterization of the mouse Xpf DNA repair gene and differential expression during spermatogenesis SO GENOMICS LA English DT Article ID NUCLEOTIDE-EXCISION-REPAIR; CDXA HOMEOBOX GENE; XERODERMA-PIGMENTOSUM; SACCHAROMYCES-CEREVISIAE; MEIOTIC RECOMBINATION; MOLECULAR-CLONING; RAD1; CELLS; ENDONUCLEASE; PROTEINS AB The human XPF protein, an endonuclease subunit essential for DNA excision repair, may also function in homologous recombination, To investigate a possible link between mammalian XPF and recombination that occurs during meiosis, we isolated, characterized, and determined an expression profile for the mouse Xpf gene. The predicted mouse XPF protein, encoded by a 3.4-kb cDNA, contains 917 amino acids and is 86% identical to human XPF. Appreciable similarity also exists between mouse XPF and homologous proteins in budding yeast (Rad1), fission yeast (Rad16), and fruit fly (Mei-9), all of which have dual functions in excision repair and recombination. Sequence analysis of the 38.3-kb Xpf gene, localized to a region in proximal mouse chromosome 16, revealed greater than 72% identity to human XPF in 16 regions. Of these conserved elements, 11 were exons and 5 were noncoding sequence within introns, Xpf transcript and protein levels were specifically elevated in adult mouse testis. Moreover, increased levels of Xpf and Ercc1 mRNAs correlated with meiotic and early postmeiotic spermatogenic cells. These results support a distinct role for the XPF/ERCC1 junction-specific endonuclease during meiosis, most likely in the resolution of heteroduplex intermediates that arise during recombination, (C) 1999 Academic Press. C1 Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Mol & Struct Biol Div, Livermore, CA 94550 USA. Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Ctr Human Genome, Livermore, CA 94550 USA. Univ Tennessee, Dept Biochem & Cellular & Mol Biol, Knoxville, TN 37996 USA. RP Thelen, MP (reprint author), Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Mol & Struct Biol Div, POB 808,L-452, Livermore, CA 94550 USA. RI Thelen, Michael/C-6834-2008; Thelen, Michael/G-2032-2014; OI Thelen, Michael/0000-0002-2479-5480; Thelen, Michael/0000-0002-2479-5480; Stubbs, Lisa/0000-0002-9556-1972 FU NICHD NIH HHS [HD31376]; NIGMS NIH HHS [GM52120] NR 42 TC 16 Z9 17 U1 0 U2 0 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 DEC 15 PY 1999 VL 62 IS 3 BP 427 EP 435 DI 10.1006/geno.1999.6016 PG 9 WC Biotechnology & Applied Microbiology; Genetics & Heredity SC Biotechnology & Applied Microbiology; Genetics & Heredity GA 280EN UT WOS:000085089400012 PM 10644440 ER PT J AU Vining, CB Mahan, GD AF Vining, CB Mahan, GD TI The B factor in multilayer thermionic refrigeration SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID THERMAL-CONDUCTIVITY; SUPERLATTICES; TRANSPORT; FIGURE; MERIT AB The figure of merit for multilayer thermionic refrigeration is discussed in terms of an effective B factor, which has a similar definition as the B factor in thermoelectrics. We show that high efficiencies for cooling or power generation are only obtained with very high values of this B factor. Such high values can only be attained because of the low thermal conductivity of multilayers. The B factor for thermionics is usually less than the one for thermoelectrics. (C) 1999 American Institute of Physics. [S0021-8979(99)05824-7]. C1 ZT Serv, Auburn, AL 36830 USA. Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Vining, CB (reprint author), ZT Serv, 2203 Johns Circle, Auburn, AL 36830 USA. NR 16 TC 50 Z9 52 U1 1 U2 6 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 DEC 15 PY 1999 VL 86 IS 12 BP 6852 EP 6853 DI 10.1063/1.371762 PG 2 WC Physics, Applied SC Physics GA 259VX UT WOS:000083915600037 ER PT J AU Gao, Y Mueller, AH Irene, EA Auciello, O Krauss, AR Schultz, JA AF Gao, Y Mueller, AH Irene, EA Auciello, O Krauss, AR Schultz, JA TI Real-time study of oxygen in c-axis oriented YBa2Cu3O7-delta thin films using in situ spectroscopic ellipsometry SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID HIGH-TC; TEMPERATURE-DEPENDENCE; INSITU GROWTH; TRANSITION; SUPERCONDUCTOR; VACANCIES; PRESSURE AB The oxygen transport process in c-axis oriented YBa2Cu3O7-delta thin films was investigated in real time during deposition and postdeposition oxidation using in situ spectroscopic ellipsometry (SE). Two transport regimes dominated by oxygen out- and in-diffusion have been observed during deposition by ion beam sputtering at 700 degrees C. The effect of oxygen partial pressure on the extent of oxidation of as-deposited films has also been studied during the postdeposition cooling process. The thermodynamic stability of the grown films was examined by real time SE during the postannealing process. The relaxation time for oxygen diffusion has been found to decrease with higher oxygen partial pressures. The imaginary part of the pseudodielectric function at an absorption peak was quantitatively correlated to the oxygen concentration. The pseudodielectric functions of oxygen deficient YBa2Cu3O6 films in the temperature range from 27 to 700 degrees C have been modeled using Lorentz oscillators. (C) 1999 American Institute of Physics. [S0021-8979(99)05224-X]. C1 Univ N Carolina, Dept Chem, Chapel Hill, NC 27599 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Ionwerks, Houston, TX 77005 USA. RP Gao, Y (reprint author), Univ N Carolina, Dept Chem, Chapel Hill, NC 27599 USA. NR 24 TC 1 Z9 1 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 DEC 15 PY 1999 VL 86 IS 12 BP 6979 EP 6984 DI 10.1063/1.371782 PG 6 WC Physics, Applied SC Physics GA 259VX UT WOS:000083915600057 ER PT J AU Asmis, KR Taylor, TR Neumark, DM AF Asmis, KR Taylor, TR Neumark, DM TI Anion photoelectron spectroscopy of B3N- SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID BORON-NITRIDE NANOTUBES; ELECTRON-AFFINITIES; HARMONIC VIBRATIONS; LASER VAPORIZATION; CARBON CLUSTERS; BASIS-SETS; ATOMS; STABILITY; NANOPARTICLES; IRRADIATION AB Vibrationally resolved negative ion photoelectron spectra of B3N- at 355 and 266 nm are presented. Two intense bands are observed with adiabatic detachment energies (ADEs) of 2.923 +/- 0.008 eV and 3.063 +/- 0.008 eV and markedly different photoelectron angular distributions. Aided by electronic structure calculations, the two bands are assigned to transitions from the linear (X) over tilde (4)Sigma(-) state of B3N- to the linear (3)Pi and (5)Sigma(-) electronically excited states of neutral B3N, with all three states having a B-N-B-B structure. Weak signal observed at lower electron binding energies is tentatively assigned to two additional linear-to-linear transitions from the low-lying electronically excited (2)Pi state of B3N- to the (1)Sigma(+) and (3)Pi states of neutral B3N. Based on these assignments the electron affinity of linear B-N-B-B is 2.098 +/- 0.035 eV. It remains uncertain if the (1)Sigma(+) state of linear B-N-B-B or the (3)A(1) state of cyclic B3N is the overall ground state. At the highest level of theory used here, CCSD(T)/aug-cc-pVTZ, the (1)Sigma(+) state is predicted to lie 0.09 eV below the (3)A(1) state. (C) 1999 American Institute of Physics. [S0021-9606(99)00746-1]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Asmis, KR (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Asmis, Knut/N-5408-2014; Neumark, Daniel/B-9551-2009 OI Asmis, Knut/0000-0001-6297-5856; Neumark, Daniel/0000-0002-3762-9473 NR 45 TC 25 Z9 25 U1 0 U2 5 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 DEC 15 PY 1999 VL 111 IS 23 BP 10491 EP 10500 DI 10.1063/1.480402 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 260AY UT WOS:000083927200014 ER PT J AU Greenblatt, BJ Zanni, MT Neumark, DM AF Greenblatt, BJ Zanni, MT Neumark, DM TI Femtosecond photoelectron spectroscopy of I-2(-)(Ar)(n) clusters (n=6,9,12,16,20) SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID NONADIABATIC MOLECULAR-DYNAMICS; GEMINATE RECOMBINATION DYNAMICS; VIBRATIONAL-RELAXATION; CHARGE FLOW; SOLVENT DYNAMICS; PHOTODISSOCIATION; IONS; I-2(-); ANION; I2 AB The photodissociation of I-2(-) embedded in mass-selected I-2(-)(Ar)(n) clusters (n = 6-20) was studied using femtosecond photoelectron spectroscopy. The (A) over tilde'<--(X) over tilde transition in the I-2(-) chromophore was excited using a femtosecond pump pulse, and the subsequent dynamics were followed by photodetachment with a femtosecond probe pulse and measurement of the resulting photoelectron spectrum. In all clusters, dissociation of the I-2(-) is complete by 300 fs. From 300 fs to 1 ps, the spectra yield the number of Ar atoms interacting with the I- fragment. At later times, recombination of I-2(-) occurs in I-2(-)(Ar)(n greater than or equal to 12) on both the (X) over tilde and (A) over tilde states. Analysis of the spectra yields the time scale for (X) over tilde state vibrational relaxation and solvent evaporation. In I-2(-)(Ar)(20), energy transfer from I-2(-) to Ar atoms through vibrational relaxation is slightly faster than energy loss from the cluster through Ar evaporation, indicating the temporary storage of energy within Ar cluster modes. (C) 1999 American Institute of Physics. [S0021-9606(99)01245-3]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Greenblatt, BJ (reprint author), NASA, Ames Res Ctr, Atmospher Chem & Dynam Branch, Mail Stop 245-5, Moffett Field, CA 94035 USA. RI Zanni, Martin/K-2707-2013; Neumark, Daniel/B-9551-2009 OI Neumark, Daniel/0000-0002-3762-9473 NR 49 TC 37 Z9 37 U1 0 U2 5 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 DEC 15 PY 1999 VL 111 IS 23 BP 10566 EP 10577 DI 10.1063/1.480433 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 260AY UT WOS:000083927200023 ER PT J AU Gao, HR Angelici, RJ AF Gao, HR Angelici, RJ TI Rhodium-phosphine complex catalysts tethered on silica-supported heterogeneous metal catalysts: arene hydrogenation under atmospheric pressure SO JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL LA English DT Article DE rhodium-phosphine complex; supported metal catalysts; TCSM; tethered complex catalysts; silica; palladium; nickel; gold ID HOMOGENEOUS HYDROGENATION; ASYMMETRIC HYDROGENATION; SELECTIVE HYDROGENATION; AROMATIC-HYDROCARBONS; SPILLOVER; ZEOLITES; LIGANDS; DERIVATIVES; OLEFINS; BENZENE AB The rhodium-phosphine complex, RhCl(CO)[Ph2P(CH2)(3)Si(OC2H5)(3)](2) (Rh-P), was tethered to silica-supported metal heterogeneous catalysts, Pd-SiO2, Ni-SiO2 and Au-SiO2, to give the tethered complex catalysts Rh-P/Pd-SiO2, Rh-P/Ni-SiO2 and Rh-P/Au-SiO2. An IR (DRIFTS) study shows that the structure of the tethered rhodium-phosphine complex (Rh-P) in all of these combination catalysts is the same as that of the free Rh-P complex. These heterogenized complex catalysts consisting of a tethered complex on a supported metal (TCSM) were used to catalyze the hydrogenation of arenas under the mild conditions of 40 degrees C and 1 arm of H-2. The most active TCSM catalyst Rh-P/Pd-SiO2 is not only much more active than the homogeneous Rh-P complex and Pd-SiO2 but also much more active than the rhodium-phosphine complex tethered on just SiO2 (Rh-P/SiO2). The Rh-P/Pd-SiO2 catalyst gives a maximum turnover frequency (TOF, mol H-2/mol Rh min) of 2.9 and a turnover (TO, mol H-2/mol Rh) of 1940 during a 23 h period in the hydrogenation of toluene. When the tethered rhodium-phosphine complex catalyst stands in air for 2 months or longer, the phosphine ligand is oxidized to the phosphine oxide. This air-aged Rh-P/Pd-SiO2 is much more active than the fresh catalyst for the hydrogenation of toluene, but the air-aged Rh-P/SiO2 becomes inactive for this reaction. These two air-aged catalysts were characterized by solid state P-31 NMR and DRIFTS using CO as a probe. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Iowa State Univ, Dept Chem, Ames, IA 50011 USA. EM angelici@iastate.edu NR 50 TC 30 Z9 31 U1 1 U2 14 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1381-1169 EI 1873-314X J9 J MOL CATAL A-CHEM JI J. Mol. Catal. A-Chem. PD DEC 15 PY 1999 VL 149 IS 1-2 BP 63 EP 74 DI 10.1016/S1381-1169(99)00182-X PG 12 WC Chemistry, Physical SC Chemistry GA 263WU UT WOS:000084148900007 ER PT J AU Perera, MADN Angelici, RJ AF Perera, MADN Angelici, RJ TI Rhodium amine complexes tethered on silica-supported gold-palladium bimetal catalysts. Arene hydrogenation SO JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL LA English DT Article DE TCSM; tethered complex catalysts; bimetallic catalysts; toluene hydrogenation; palladium; gold ID AROMATIC-HYDROCARBONS; METAL COMPLEXES; LIGANDS; ENANTIOSELECTIVITY; CHEMISORPTION; DERIVATIVES; REACTIVITY; MILD AB Arene hydrogenation activities of catalysts prepared by:tethering. Rh(COD)[H2NCH2CH2NHCH2CH2CH2Si(OCH3)(3)](X) on the silica support of the bimetal catalyst Au:Pb-SiO2 were studied under the mild conditions of 40 degrees C and 1 atm H-2 pressure. The most active catalyst PF6-Rh(N-N)/Au:Pd-SiO2, with the weakly coordinating PF6 anion, remains highly active for toluene hydrogenation through at least three catalytic cycles involving 2900 mol H-2/mol Rh turnovers over a 19-h period. As compared with the activity of the Pd-supported catalyst PF6-Rh(N-N)/Pd-SiO2, the catalysts with added Au are less active only by a factor of two. But the activity depends strongly on the Pd and Rh complex loadings, Although the detailed functioning of these TCSM catalysts (tethered complex on a supported metal) is not known, a mechanism that is consistent with the results involves dissociative adsorption of H-2 On the supported Pd. The hydrogen spills over onto the silica surface where the Rh complex uses it to hydrogenate the arene substrate. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Angelici, RJ (reprint author), Iowa State Univ, Dept Chem, Gilman Hall, Ames, IA 50011 USA. NR 42 TC 8 Z9 8 U1 1 U2 7 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 DEC 15 PY 1999 VL 149 IS 1-2 BP 99 EP 111 DI 10.1016/S1381-1169(99)00209-5 PG 13 WC Chemistry, Physical SC Chemistry GA 263WU UT WOS:000084148900010 ER PT J AU Monar, K Habenschuss, A AF Monar, K Habenschuss, A TI Modeling the principal amorphous halo in quiescent melts of polyethylene and ethylene copolymers using wide-angle X-ray scattering and its implications SO JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS LA English DT Article; Proceedings Paper CT Meeting of the American-Physical-Society-Division-of-High-Polymer-Physics CY MAR, 1999 CL ATLANTA, GEORGIA SP Amer Phys Soc Div High Polymer Phys DE wide-angle X-ray scattering; polyethylene; glass transition; free volume; amorphous halo ID DIFFRACTION; POLYMERS; TEMPERATURE; POLY(ETHYLENE-TEREPHTHALATE); CRYSTALLINITY; TRANSITION; ALKANES AB Wide-angle X-ray scattering (WAXS) studies of the melts of polyethylenes indicate that the low-angle amorphous halo (LAH) retains "sensible" information regarding the liquid state, which can be used to model the amorphous fraction in the semicrystalline state. The LAH was found to consist of a temperature-independent and a temperature-dependent region. A linear relationship was observed for the temperature dependence of the LAH peak value below 135 degrees C in branched ethylene copolymers, and was found dependent on comonomer concentration. When combined with group contribution theory, a simple model of average intermolecular separation determined from the WAXS-LAH peak value is consistent with free volume considerations, both with respect to predicting T-g(infinity) and the free volume expansion coefficient. The polyethylene, without branches, shows a different behavior in the region 131-160 degrees C. A semiquantitative method is proposed to model the scattering from the LAH for use in the phase analysis of the copolymers through the separation of the temperature-dependent (intermolecular) and temperature-independent (intramolecular) fractions. (C) 1999 John Wiley & Sons, Inc. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Monar, K (reprint author), Oak Ridge Natl Lab, 4500 C8,MS 6197, Oak Ridge, TN 37831 USA. NR 38 TC 14 Z9 14 U1 2 U2 9 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0887-6266 J9 J POLYM SCI POL PHYS JI J. Polym. Sci. Pt. B-Polym. Phys. PD DEC 15 PY 1999 VL 37 IS 24 BP 3401 EP 3410 DI 10.1002/(SICI)1099-0488(19991215)37:24<3401::AID-POLB3>3.3.CO;2-P PG 10 WC Polymer Science SC Polymer Science GA 261ZW UT WOS:000084042100003 ER PT J AU Yew, WS Kolatkar, PR Kuhn, P Khoo, HE AF Yew, WS Kolatkar, PR Kuhn, P Khoo, HE TI Crystallization and preliminary crystallographic study of stonustoxin, a protein lethal factor isolated from the stonefish (Synanceja horrida) venom SO JOURNAL OF STRUCTURAL BIOLOGY LA English DT Article AB Crystals of stonustoxin have been obtained and diffract to 3.4 Angstrom resolution. Stonustoxin is a protein lethal factor isolated from the venom of the stonefish, Synanceja horrida. The crystals belong to the tetragonal space group P422, with unit cell constants a = b = 109.0 Angstrom, c = 245.7 Angstrom. A native stonustoxin molecule has two subunits, designated alpha and beta, respectively, and there is one stonustoxin molecule per asymmetric unit. (C) 1999 Academic Press. C1 Natl Univ Singapore, Fac Med, Dept Biochem, Singapore 119260, Singapore. Natl Univ Singapore Hosp, Bioinformat Ctr, Singapore 119074, Singapore. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Khoo, HE (reprint author), Natl Univ Singapore, Fac Med, Dept Biochem, 10 Kent Ridge Crescent, Singapore 119260, Singapore. EM bchkhe@nus.edu.sg OI kolatkar, prasanna/0000-0003-4970-5944 NR 13 TC 2 Z9 5 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1047-8477 EI 1095-8657 J9 J STRUCT BIOL JI J. Struct. Biol. PD DEC 15 PY 1999 VL 128 IS 2 BP 216 EP 218 DI 10.1006/jsbi.1999.4193 PG 3 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 273GV UT WOS:000084700300009 PM 10600575 ER PT J AU Choi, CH Gordon, MS AF Choi, CH Gordon, MS TI Cycloaddition reactions of 1,3-cyclohexadiene on the silicon(001) surface SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID MM3 FORCE-FIELD; DEGENERATE PERTURBATION-THEORY; DIELS-ALDER REACTIONS; MOLECULAR MECHANICS; SI(100)-2X1 SURFACE; SI(001) SURFACE; DOUBLE-BOND; HYDROCARBONS; CHEMISTRY; ETHYLENE AB [2+2] and [4+2] cycloaddition reactions of 1,3-cyclohexadiene on the Si(001) surface were studied. It is shown that not only the [4+2] cycloaddition reaction but also the [2+2] cycloadditions can occur on the Si(001) surface. Surface isomerization reactions connecting [4+2] and [2+2] are very unlikely due to a high energy barrier, implying that the surface reactions are kinetically controlled. Therefore the final surface reaction products are determined during the initial stage of the reactions in contrast with earlier assumptions that the "product distribution is thermodynamically determined". Our interpretations are consistent with the new experimental results by the Hamers group. According to our CASSCF(6,6) calculations, the nonsymmetric ct-complex transition states along the [2+2] cycloaddition mechanism, which has been suggested by many theoretical studies, seem to be an artifact. Nevertheless, the very soft Si dimer buckling motion of the Si(001) surface certainly facilitates the [2+2] reaction. C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. RP Gordon, MS (reprint author), Iowa State Univ Sci & Technol, Ames Lab, 201 Spedding Hall, Ames, IA 50011 USA. NR 50 TC 114 Z9 114 U1 0 U2 4 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 DEC 15 PY 1999 VL 121 IS 49 BP 11311 EP 11317 DI 10.1021/ja9914285 PG 7 WC Chemistry, Multidisciplinary SC Chemistry GA 266NT UT WOS:000084306600008 ER PT J AU Berning, DE Noll, BC DuBois, DL AF Berning, DE Noll, BC DuBois, DL TI Relative hydride, proton, and hydrogen atom transfer abilities of [HM(diphosphine)(2)]PF6 complexes (M = Pt, Ni) SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID TRANSITION-METAL COMPLEXES; BOND-DISSOCIATION ENERGIES; COORDINATED CARBON-MONOXIDE; HIGHER OXIDATION-STATES; THERMODYNAMIC ACIDITY; REACTION ENTROPIES; REDOX COUPLES; DIHYDROGEN COMPLEXES; TRIHYDRIDE COMPLEXES; ELECTRODE-POTENTIALS AB A series of [M(diphosphine)(2)]X-2, [HM(diphosphine)(2)]X, and M(diphosphine)(2) complexes have been prepared for the purpose of determining the relative thermodynamic hydricities of the [HM(diphosphine)(2)]X complexes (M = Ni, Pt; X = BF4, PF6; diphosphine = bis(diphenylphosphino)ethane (dppe), bis(diethylphosphino)ethane (depe), bis(dimethylphosphino)ethane (dmpe), bis(dimethylphosphino)propane (dmpp)). Measurements of the half-wave potentials (E-1/2) for the M(II) and M(O) complexes and pK(a) measurements for the metal hydride complexes have been used in a thermochemical cycle to obtain quantitative thermodynamic information on the relative hydride donor abilities of the metal-hydride complexes. The hydride donor strengths vary by 23 kcal/mol and are influenced by the metal, the ligand substituents, and the size of the chelate bite of the diphosphine Ligand. The best hydride donor of the complexes prepared is [HPt(dmpe)(z)](PF6), a third-row transition metal with basic substituents and a diphosphine ligand with a small chelate bite. The best hydride accepters have the opposite characteristics. X-ray diffraction studies were carried out on eight complexes: [Ni(dmpe)(2)](BF4)(2), [Ni(depe)(2)](BF4)(2), [Ni(dmpp)(2)](BF4)(2), [Pt(dmpp)(2)](PF6)(2), [Ni(dmpe)(2)(CH3CN)] (BF4)(2), [Ni(dmpp)(2)(CH3CN)](BF4)(2), Ni(dmpp)(2), and Pt(dmpp)(2). The cations [Ni(dmpp)(2)](2+) and [Pt(dmpp)(2)](2+) exhibit significant tetrahedral distortions from a square-planar geometry arising from the larger chelate bite of dmpp compared to that of dmpe. This tetrahedral distortion produces a decrease in the energy of the lowest unoccupied molecular orbital of the [M(dmpp)(2)](2+) complexes, stabilizes the +1 oxidation state, and makes the [HM(dmpp)(2)](+) complexes poorer hydride donors than their dmpe analogues. Another interesting structural feature is the shortening of the M-P bond upon reduction from M(II) to M(O). C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP DuBois, DL (reprint author), Natl Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80401 USA. NR 93 TC 146 Z9 146 U1 3 U2 25 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 DEC 15 PY 1999 VL 121 IS 49 BP 11432 EP 11447 DI 10.1021/ja991888y PG 16 WC Chemistry, Multidisciplinary SC Chemistry GA 266NT UT WOS:000084306600021 ER PT J AU Saxena, A Sanati, M Albers, RC AF Saxena, A Sanati, M Albers, RC TI Domain walls in bcc to hcp reconstructive phase transformations SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT International Conference on Martensitic Transformations CY DEC 07-11, 1998 CL SAN CARLOS BARILO, ARGENTINA SP Fdn Antorchas, Consejo Nacl Invest Cient Tecnicas, Inst Invest Cient & Tecnicas Fuerzas Armadas DE Landau-Ginzburg model; domain walls; reconstructive phase transformations; bcc/hcp; shear/shuffle ID GROUP-IV METALS; LANDAU-GINZBURG MODEL; INTERPHASE BOUNDARIES; PHONON-DISPERSION; TRANSITIONS; BAND; ZR AB The bcc (body-centered cubic) phase to hcp (hexagonal closed pack) phase transformation in certain elements (e.g. Ti) and alloys is induced either by quenching or application of pressure. To study domain walls in these materials we have extended the Landau model of Lindgard and Mouritsen by including a spatial gradient (Ginzburg) term of the scalar order parameter. Through first-principles calculations, we show that the bcc structure is unstable with respect to the shuffle of atoms rather than the shear. Therefore, we can reduce the multiple (two) order parameter (OP) Landau free energy (LFE) to an effective one OP (shuffle) potential, which is a reasonable approximation. In general, the effective LFE is a triple-well potential. From the variational derivative of the total free energy we obtain a static equilibrium condition. By solving this equation for different physical parameters and boundary conditions, we obtain different quasi-one-dimensional soliton-like solutions which correspond to four types of domain walls between the bcc phase and the hcp phase. (C) 1999 Published by Elsevier Science S.A. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Cincinnati, Dept Phys, Cincinnati, OH 45221 USA. RP Saxena, A (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. EM avadh@lanl.gov NR 25 TC 4 Z9 4 U1 1 U2 4 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 DEC 15 PY 1999 VL 273 SI SI BP 226 EP 230 DI 10.1016/S0921-5093(99)00376-7 PG 5 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 270WP UT WOS:000084560400026 ER PT J AU Vaidyanathan, R Bourke, MAM Dunand, DC AF Vaidyanathan, R Bourke, MAM Dunand, DC TI Stress-induced martensitic transformations in NiTi and NiTi-TiC composites investigated by neutron diffraction SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT International Conference on Martensitic Transformations CY DEC 07-11, 1998 CL SAN CARLOS BARILO, ARGENTINA SP Fdn Antorchas, Consejo Nacl Invest Cient Tecnicas, Inst Invest Cient & Tecnicas Fuerzas Armadas DE shape-memory; superelasticity; metal matrix composites; neutron diffraction; Rietveld refinement; phase transformation ID SHAPE-MEMORY RECOVERY; BEHAVIOR; ALLOY AB Superelastic NiTi (51.0 at.% Ni) specimens reinforced with 0, 10 and 20 vol.% TiC particles were deformed under uniaxial compression while neutron diffraction spectra were collected. The experiments yielded in-situ measurements of the thermoelastic stress-induced transformation. The evolution of austenite/martensite phase fractions and of elastic strains in the reinforcing TiC particles and the austenite matrix were obtained by Rietveld refinement [1] during the loading cycle as the austenite transforms to martensite (and its subsequent back transformation during unloading). Phase fractions and strains are discussed in terms of load transfer in composites where the matrix undergoes a stress-induced phase transformation. (C) 1999 Elsevier Science S.A. All rights reserved. C1 MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA. Univ Calif Los Alamos Natl Lab, MST, LANSCE, Los Alamos, NM 87545 USA. RP Dunand, DC (reprint author), Northwestern Univ, Dept Mat Sci & Engn, 2225 N Campus Dr, Evanston, IL 60208 USA. EM dunand@nwu.edu RI Dunand, David/B-7515-2009; OI Dunand, David/0000-0001-5476-7379 NR 29 TC 16 Z9 16 U1 0 U2 4 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 DEC 15 PY 1999 VL 273 SI SI BP 404 EP 409 DI 10.1016/S0921-5093(99)00307-X PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 270WP UT WOS:000084560400063 ER PT J AU Williams, RM Kelly, JF Hartman, JS Sharpe, SW Taubman, MS Hall, JL Capasso, F Gmachl, C Sivco, DL Baillargeon, JN Cho, AY AF Williams, RM Kelly, JF Hartman, JS Sharpe, SW Taubman, MS Hall, JL Capasso, F Gmachl, C Sivco, DL Baillargeon, JN Cho, AY TI Kilohertz linewidth from frequency-stabilized mid-infrared quantum cascade lasers SO OPTICS LETTERS LA English DT Article ID SPECTROSCOPY; PHASE AB Frequency stabilization of mid-IR quantum cascade (QC) lasers to the kilohertz level has been accomplished by use of electronic servo techniques. With this active feedback, an 8.5-mu m QC distributed-feedback laser is locked to the side of a rovibrational resonance of nitrous oxide (N2O) at 1176.61 cm(-1). A stabilized frequency-noise spectral density of 42 Hz/root Hz has been measured at 100 kHz; the calculated laser linewidth is 12 kHz. (C) 1999 Optical Society of America OCIS codes: 000.2170, 120.5050, 120.4820, 140.5960, 000.2170. C1 Pacific NW Lab, Richland, WA 99352 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. RP Williams, RM (reprint author), Pacific NW Lab, MS K5-25,POB 999, Richland, WA 99352 USA. NR 15 TC 82 Z9 82 U1 0 U2 10 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 DEC 15 PY 1999 VL 24 IS 24 BP 1844 EP 1846 DI 10.1364/OL.24.001844 PG 3 WC Optics SC Optics GA 269TL UT WOS:000084493600018 PM 18079950 ER PT J AU McGuire, JA Beck, W Wei, X Shen, YR AF McGuire, JA Beck, W Wei, X Shen, YR TI Fourier-transform sum-frequency surface vibrational spectroscopy with femtosecond pulses SO OPTICS LETTERS LA English DT Article ID GENERATION AB We present a Fourier-transform spectroscopic technique for investigation of surfaces and interfaces based on IR-visible sum-frequency generation with femtosecond light pulses. The observed spectrum has a resolution that is independent of the input pulse characteristics. (C) 1999 Optical Society of America OCIS codes: 190.4350, 300.6300, 190.7110, 300.6490. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat & Chem Sci, Berkeley, CA 94720 USA. RP McGuire, JA (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI McGuire, John/C-3380-2015 OI McGuire, John/0000-0002-0682-0953 NR 5 TC 25 Z9 25 U1 1 U2 7 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 DEC 15 PY 1999 VL 24 IS 24 BP 1877 EP 1879 DI 10.1364/OL.24.001877 PG 3 WC Optics SC Optics GA 269TL UT WOS:000084493600029 PM 18079961 ER PT J AU Manciu, M Sen, S Hurd, AJ AF Manciu, M Sen, S Hurd, AJ TI The propagation and backscattering of soliton-like pulses in a chain of quartz beads and related problems. (I). Propagation SO PHYSICA A LA English DT Article ID GENERALIZED LANGEVIN EQUATION; RECURRENCE RELATIONS; GRANULAR COLUMNS; WAVES; MEDIA AB We confirm that for vanishingly small loading and large impact condition, it may be possible to generate solitons in a chain of grains that are characterized by Hertzian contacts. For uniform or progressive loading conditions throughout the chain, one generates soft-solitons which are weakly dispersive in space and time. Under conditions of weak impact, one generates acoustic pulses through the chain. We describe the displacements, velocities and accelerations suffered by the individual grains when subjected to solitons, soft-solitons and acoustic pulses and describe the effects of restitution on the propagating pulse. (C) 1999 Elsevier Science B.V. All rights reserved. C1 SUNY Buffalo, Dept Phys, Buffalo, NY 14260 USA. SUNY Buffalo, Ctr Adv Photon & Elect Mat, Buffalo, NY 14260 USA. Sandia Natl Labs, Dept 1841, Albuquerque, NM 87185 USA. RP Sen, S (reprint author), SUNY Buffalo, Dept Phys, Buffalo, NY 14260 USA. RI Manciu, Marian/C-7247-2017 OI Manciu, Marian/0000-0003-4821-4131 NR 25 TC 34 Z9 34 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4371 J9 PHYSICA A JI Physica A PD DEC 15 PY 1999 VL 274 IS 3-4 BP 588 EP 606 DI 10.1016/S0378-4371(99)00371-4 PG 19 WC Physics, Multidisciplinary SC Physics GA 268BG UT WOS:000084394000020 ER PT J AU Manciu, M Sen, S Hurd, AJ AF Manciu, M Sen, S Hurd, AJ TI The propagation and backscattering of soliton-like pulses in a chain of quartz beads and related problems. (II). Backscattering SO PHYSICA A LA English DT Article AB We demonstrate that the propagation of solitons, soliton-like excitations and acoustic pulses discussed in the preceding article (M, Manciu, S. Sen and A.J. Hurd, Physica A, preceding article) can be used to detect buried impurities in a chain of elastic grains with Hertzian contacts. We also present preliminary data for 3D granular beds, where soliton-like objects can form and can be used to probe for buried impurities, thus suggesting that soliton-pulse spectroscopy! has the potential to become a valuable tool for probing the structural properties of granular assemblies. The effects of restitution are briefly discussed. We refer to available experiments which support our contention, (C) 1999 Elsevier Science B.V. All rights reserved. C1 SUNY Buffalo, Dept Phys, Buffalo, NY 14260 USA. SUNY Buffalo, Ctr Adv Photon & Elect Mat, Buffalo, NY 14260 USA. Sandia Natl Labs, Dept 1841, Albuquerque, NM 87185 USA. RP Sen, S (reprint author), SUNY Buffalo, Dept Phys, Buffalo, NY 14260 USA. RI Manciu, Marian/C-7247-2017 OI Manciu, Marian/0000-0003-4821-4131 NR 9 TC 39 Z9 39 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4371 J9 PHYSICA A JI Physica A PD DEC 15 PY 1999 VL 274 IS 3-4 BP 607 EP 618 DI 10.1016/S0378-4371(99)00372-6 PG 12 WC Physics, Multidisciplinary SC Physics GA 268BG UT WOS:000084394000021 ER PT J AU Marinescu, DC Quinn, JJ AF Marinescu, DC Quinn, JJ TI Coupling of spin waves with charge- and spin-density excitations in spin-polarized quantum wells SO PHYSICAL REVIEW B LA English DT Article ID ELECTRON-GAS AB The coupling of spin waves with charge- and spin-density waves is shown to be induced by a spin-dependent interaction in a quantum well, which is spin polarized by a de magnetic field at an angle theta to the symmetry axis. The mixing of the plasmonic and magnonic modes, which occurs for both intra- and intersubband transitions, depends on the coupling constant of the spin-spin interaction, the tilt angle theta, and the initial spin polarization zeta. [S0163-1829(99)08247-8]. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Phys, Knoxville, TN 37906 USA. RP Marinescu, DC (reprint author), Clemson Univ, Dept Phys, Clemson, SC 29634 USA. NR 7 TC 2 Z9 2 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 DEC 15 PY 1999 VL 60 IS 23 BP 15566 EP 15569 DI 10.1103/PhysRevB.60.15566 PG 4 WC Physics, Condensed Matter SC Physics GA 272BZ UT WOS:000084631800026 ER PT J AU Watanabe, M Itoh, KM Ootuka, Y Haller, EE AF Watanabe, M Itoh, KM Ootuka, Y Haller, EE TI Metal-insulator transition of isotopically enriched neutron-transmutation-doped Ge-70 : Ga in magnetic fields SO PHYSICAL REVIEW B LA English DT Article ID DISORDERED-SYSTEMS; MOBILITY EDGE; SI-B; CONDUCTIVITY; GERMANIUM AB We have investigated the temperature dependence of the electrical conductivity sigma(N,B,T) of nominally uncompensated, neutron-transmutation-doped Ge-70:Ga samples in magnetic fields up to B = 8 T at low temperatures (T = 0.05 - 0.5 K). In our earlier studies at B = 0, the critical exponent mu = 0.5 defined by sigma(N,0,0)proportional to(N-N-c)(mu) has been determined for the same series of Ge-70:Ga samples with the doping concentration N ranging from 1.861 X 10(17) cm(-3) to 2.434 X 10(17) cm(-3). In magnetic fields, the motion of carriers loses time-reversal symmetry, the universality class may change and with it the value of mu. In this work, we show that magnetic fields indeed affect the value of mu (mu changes from 0.5 at B = 0 to 1.1 at B greater than or equal to 4 T). The same exponent mu' = 1.1 is also found in the magnetic-field-induced MIT for three different Ge-70: Ga samples, i.e., sigma(N,B,0)proportional to[B-c(N)-B](mu') where B-c(N) is the concentration-dependent critical magnetic induction. We show that sigma(N,B,0) obeys a simple scaling rule on the (N,B) plane. Based on this finding, we derive from a simple mathematical argument that mu = mu' as has been observed in our experiment. [S0163-1829(99)10447-8]. C1 Keio Univ, Dept Appl Phys & Physicoinformat, Kohoku Ku, Yokohama, Kanagawa 2238522, Japan. JST, PRESTO, Kohoku Ku, Yokohama, Kanagawa 2238522, Japan. Univ Tsukuba, Inst Phys, Tsukuba, Ibaraki 3058571, Japan. Univ Calif Berkeley, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Watanabe, M (reprint author), Keio Univ, Dept Appl Phys & Physicoinformat, Kohoku Ku, 3-14-1 Hiyoshi, Yokohama, Kanagawa 2238522, Japan. RI Itoh, Kohei/C-5738-2014 NR 26 TC 10 Z9 10 U1 1 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 DEC 15 PY 1999 VL 60 IS 23 BP 15817 EP 15823 DI 10.1103/PhysRevB.60.15817 PG 7 WC Physics, Condensed Matter SC Physics GA 272BZ UT WOS:000084631800067 ER PT J AU Shinar, J Shinar, R Williamson, DL Mitra, S Kavak, H Dalal, VL AF Shinar, J Shinar, R Williamson, DL Mitra, S Kavak, H Dalal, VL TI Microstructure and hydrogen dynamics in hydrogenated amorphous silicon carbides SO PHYSICAL REVIEW B LA English DT Article ID A-SI-H; X-RAY-SCATTERING; MEYER-NELDEL RELATION; DISPERSIVE DIFFUSION; STRUCTURAL RELAXATION; INFRARED-ABSORPTION; GERMANIUM ALLOYS; CARBON ALLOYS; MICROVOIDS; DEPOSITION AB Small angle x-ray scattering (SAXS) and deuterium secondary-ion-mass spectrometry (DSIMS) studies of the microstructure and hydrogen dynamics in undoped rf-sputter-deposited (RFS) and undoped and boron-doped electron-cyclotron-resonance-deposited (ECR) hydrogenated amorphous silicon carbides (a-Sil-xCx:H) are described. In the RFS carbides with x less than or equal to 9 at. %, the SAXS indicated that the films contained elongated features larger than 20 nm with preferred orientation, consistent with a residual columnarlike growth of the films. In addition, the SAXS also included a clear nanostructural component consistent with roughly spherical nanovoids similar to 1.1 nm in diameter, of total content 0.5 less than or equal to C(nv)less than or equal to 1.0 vol. %. C-nV increased by similar to 100% after isochronal 1-h annealing at 300, 350, and 375 degrees C, followed by further annealing for 2-15 hours at 375 degrees C. The growth of C-nV was apparently due largely to a similar to 20% increase in the average void diameter. This growth was noticeably weaker than in similarly fabricated a-Si:H. In RFS carbides with x less than or equal to 3 at. %, the DSIMS yielded power-law time dependent H diffusion constants D(t)= D-00(omega t)(-alpha), where the dispersion parameter ct varied from 0 to similar to 0.5+/-0.1 among the samples, but was temperature independent at 350 degrees less than or equal to T less than or equal to 475 degrees C. The moderate values of a are consistent with the moderate initial nanovoid contents C(nV)less than or equal to 1.0 vol. % determined by SAXS. The weak dependence of cu on Tis consistent with the weaker growth of the SAXS with annealing as compared to a-Si:H. The values of activation energy E-a(1000 Angstrom) for a diffusion length L=1000 Angstrom among the different films were similar to 1.7, similar to 1.4, and similar to 0.65 eV. While the first two values are similar to those found in a-Si:H, the nature of the anomalously low value of -0.65 eV is not clear. In undoped ECR a-Si0.86C0.14:H, D(t) exhibited a similar power-law time dependence, but alpha decreased from similar to 0.3 at 350 degrees C and 400 degrees C to similar to 0.1 at 450 degrees C, also consistent with a low C-nV. Thus, in spite of the high-C content, the behavior of Lu was similar to that of typical a-Si:H at lower temperatures, where it decreases at T less than or equal to 350 degrees C. However, E-a(1000 Angstrom)was an anomalously low similar to 1.0 eV. The evolution of the infrared (IR) spectra of both the RFS and ECR films showed that during annealing the Si-bonded H content decreases relative to the C-bonded H content, consistent with a transfer of H from Si- to C-bonded sites or hydrogen evolution. In addition, the reduction in the 2000-cm(-1) band characteristic of bulk-like Si-H group was much greater than the reduction of the 2100-cm(-1) band characteristic of surface Si-H, O-Si-H, and C-Si-H groups. Boron doping of the ECR carbides also reduced the bulklike Si-bonded H content, suggesting that it induces nanovoids, consistent with the observed suppression of long-range motion of most of the H and D atoms. However, a small fraction of the H atoms appeared to undergo fast diffusion, reminiscent of the fast diffusion in B-doped a-Si:H. [S0163-1829(99)07247-1]. C1 USDOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. Iowa State Univ, Ctr Microelect Res, Ames, IA 50011 USA. Colorado Sch Mines, Dept Phys, Golden, CO 80401 USA. Univ Tulsa, Dept Engn Phys, Tulsa, OK 74104 USA. Cukurova Univ, Dept Phys, TR-101330 Adana, Turkey. Iowa State Univ, Dept Elect & Comp Engn, Ames, IA 50011 USA. RP Shinar, J (reprint author), USDOE, Ames Lab, Ames, IA 50011 USA. NR 51 TC 11 Z9 11 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 DEC 15 PY 1999 VL 60 IS 23 BP 15875 EP 15889 DI 10.1103/PhysRevB.60.15875 PG 15 WC Physics, Condensed Matter SC Physics GA 272BZ UT WOS:000084631800073 ER PT J AU McMahon, WE Olson, JM AF McMahon, WE Olson, JM TI Atomic-resolution STM study of a structural phase transition of steps on vicinal As/Ge(100) SO PHYSICAL REVIEW B LA English DT Article ID MOLECULAR-BEAM EPITAXY; ANTIPHASE DOMAINS; SILICON SURFACES; GROWTH; GAAS; GE AB Scanning tunneling microscope images of arsenic-exposed vicinal Ge(100) surfaces show that most As/Ge steps are reconstructed and that a variety of different step structures exist. The entire family of reconstructed As/Ge steps can be divided into two types, which we have chosen to call "single-row" (SR) steps and "double-row" (DR) steps. By changing the sample preparation conditions, we are able to consistently change the ratio of SR/DR steps. In other words, we have observed a structural phase transition in the reconstruction of As/Ge steps at atomic resolution. [S0163-1829(99)02847-7]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP McMahon, WE (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. NR 16 TC 9 Z9 11 U1 1 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 DEC 15 PY 1999 VL 60 IS 23 BP 15999 EP 16005 DI 10.1103/PhysRevB.60.15999 PG 7 WC Physics, Condensed Matter SC Physics GA 272BZ UT WOS:000084631800091 ER PT J AU Benedek, R Seidman, DN Minkoff, M Yang, LH Alavi, A AF Benedek, R Seidman, DN Minkoff, M Yang, LH Alavi, A TI Atomic and electronic structure and interatomic potentials at a polar ceramic/metal interface: {222}MgO/Cu SO PHYSICAL REVIEW B LA English DT Article ID HETEROPHASE INTERFACES; MOLECULAR-DYNAMICS; FIRST-PRINCIPLES; CHARGE-TRANSFER; MGO INTERFACES; POINT-DEFECTS; METAL; MICROSCOPY; ADHESION; SURFACE AB Local density functional theory (LDFT) calculations, within the plane-wave-pseudopotential framework, are performed for the {222}MgO/Cu polar interface, with the objective of elucidating the atomic and electronic structure of the interface, as well as interface interatomic potentials. Calculations are performed for both coherent interfaces and semicoherent interfaces that approximate the lattice constant mismatch of the true system. Calculations of local electronic density of states and adhesive energies are performed primarily for coherent interfaces. The density of electronic states at the interface for the oxygen-terminated configuration exhibits a peak in the bulk MgO energy gap that results from O(2p)-Cu(3d) hybridization. The calculated interface adhesive energies for coherent interfaces as a function of the interface spacing and translation state are well reproduced by a simple analytical expression that combines an attractive Rydberg-function term and a repulsive pairwise Born-Mayer potential across the interface. Calculations are performed for a semicoherent interface with 5x5 Cu layer unit cells opposite 4x4 MgO layer unit cells, an approximation to the true system with lattice constant ratio of 7/6, to investigate the relaxation at the interface in the presence of misfit. The terminating oxygen layer as well as the interface Cu layer exhibits warping albeit on a scale of less than 0.1 Angstrom. [S0163-1829(99)12047-2]. C1 Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. Lawrence Livermore Natl Lab, Condensed Matter Phys Div, Livermore, CA 94551 USA. Queens Univ Belfast, Sch Math & Phys, Belfast BT7 1NN, Antrim, North Ireland. RP Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. RI Seidman, David/B-6697-2009 NR 67 TC 46 Z9 46 U1 2 U2 19 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD DEC 15 PY 1999 VL 60 IS 23 BP 16094 EP 16102 DI 10.1103/PhysRevB.60.16094 PG 9 WC Physics, Condensed Matter SC Physics GA 272BZ UT WOS:000084631800105 ER PT J AU Bergara, A Pitarke, JM Ritchie, RH AF Bergara, A Pitarke, JM Ritchie, RH TI Hydrodynamic approximation for the nonlinear response of a metal surface SO PHYSICAL REVIEW B LA English DT Article ID ELECTRON-GAS; CHARGED-PARTICLES; STOPPING POWER; ENERGY-LOSS; IONS; MODEL; SOLIDS; FIELD AB We present semiclassical and quantized hydrodynamic models to obtain the quadratic electronic response of a plane-bounded electron gas. Explicit expressions for the dynamic image potential experienced by charged particles moving near a jellium surface are derived, up to third order in the projectile charge. These expressions are employed to compute the image potential at all distances outside the surface. Though nonlinear corrections are found to be more important far inside the solid than outside, our results indicate that the nonlinear image potential is enhanced with respect to the linear image potential by a factor that is for Al as large as similar to 1.15 near the surface in the case of a stationary particle (v --> 0) with positive unit charge e. [S0163-1829(99)08847-5]. C1 Euskal Herriko Unibertsitatea, Zientzi Fak, Mat Kondentsatuaren Fis Saila, Bilbao 48080, Basque Country, Spain. UPV, EHU, CSIC, Donostia Int Phys Ctr, Donostia San Sebastian, Basque Country, Spain. UPV, EHU, CSIC, Ctr Mixto, Donostia San Sebastian, Basque Country, Spain. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Euskal Herriko Unibertsitatea, Zientzi Fak, Mat Kondentsatuaren Fis Saila, 644 Posta Kutxatila, Bilbao 48080, Basque Country, Spain. RI Pitarke, Jose/C-8602-2009; DONOSTIA INTERNATIONAL PHYSICS CTR., DIPC/C-3171-2014; Bergara, Aitor/G-2434-2016; CSIC-UPV/EHU, CFM/F-4867-2012 OI Pitarke, Jose/0000-0002-8253-8028; NR 39 TC 6 Z9 6 U1 0 U2 8 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD DEC 15 PY 1999 VL 60 IS 23 BP 16176 EP 16185 DI 10.1103/PhysRevB.60.16176 PG 10 WC Physics, Condensed Matter SC Physics GA 272BZ UT WOS:000084631800117 ER PT J AU Haffner, S Olson, CG Lynch, DW AF Haffner, S Olson, CG Lynch, DW TI Evidence for replicate 5p core levels in photoelectron spectra of Eu metal due to nonconstant kinetic-energy resonant Auger decay SO PHYSICAL REVIEW B LA English DT Article ID PHOTOEMISSION SPECTRA; 4F AB Satellites on the low-binding-energy side of core-level photoelectron emission due to extra 4f screening are a well-known feature in the x-ray photoelectron spectra of valence fluctuation materials and rare-earth metals. A notable exception is Eu metal, where up to now no low-binding-energy satellite has been observed. In this paper we show that in Eu metal the 4d-4f resonance can decay via a resonant Auger decay, which is not a constant kinetic-energy feature due to a rapid change of the strength of 4f screening with excitation energy, establishing a low-binding-energy replica of the 5p care-level photoelectron emission. [S0163-1829(99)01348-X]. C1 Iowa State Univ, US DOE, Dept Phys, Ames, IA 50011 USA. Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA. RP Haffner, S (reprint author), Iowa State Univ, US DOE, Dept Phys, Ames, IA 50011 USA. NR 16 TC 5 Z9 5 U1 2 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 DEC 15 PY 1999 VL 60 IS 24 BP 16346 EP 16349 DI 10.1103/PhysRevB.60.16346 PG 4 WC Physics, Condensed Matter SC Physics GA 274XX UT WOS:000084791300025 ER PT J AU Muller, S Wang, LW Zunger, A Wolverton, C AF Muller, S Wang, LW Zunger, A Wolverton, C TI Coherent phase stability in Al-Zn and Al-Cu fcc alloys: The role of the instability of fcc Zn SO PHYSICAL REVIEW B LA English DT Article ID SHORT-RANGE-ORDER; TOTAL-ENERGY CALCULATIONS; AT-PERCENT ZN; SINGLE-CRYSTALS; BRILLOUIN-ZONE; SPECIAL POINTS; ELASTIC-CONSTANTS; FIRST-PRINCIPLES; LOCAL STABILITY; SOLID-SOLUTIONS AB The coherent phase stability of fee-based Al-Zn and Al-Cu alloys is studied theoretically by first-principles total energy calculations, a mixed-space cluster expansion approach, and Monte Carlo thermodynamic simulations. We find that a large portion of the differences between Al-Zn and AI-Cu can be explained by the differences between fcc-Zn and fcc-Cu: While Zn is stable in the hcp structure, fcc-Zn shows an instability when deformed rhombohedrally along (111). In contrast, fcc-Cu is the stable form of Cu and is elastically extremely soft when deformed along (100). These elastically soft directions of the constituents permeate the phase stability of the alloys: (111) superlattices are the lowest energy coherent structures in Al-Zn, while (100) superlattices are stable coherent phases in AI-Cu. The short-range order of both Al-rich solid solutions show clustering tendencies, with the diffuse intensity due to short-range order in Al-Zn and AI-Cu showing streaks along (111) and (100), respectively. The mixing enthalpies and coherent phase boundaries are also calculated and found to be in good agreement with experimental data, where available. [S0163-1829(99)01146-7]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. Ford Motor Co, Res Lab, Dearborn, MI 48121 USA. RP Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Wolverton, Christopher/B-7542-2009; Zunger, Alex/A-6733-2013 NR 75 TC 52 Z9 52 U1 1 U2 11 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD DEC 15 PY 1999 VL 60 IS 24 BP 16448 EP 16462 DI 10.1103/PhysRevB.60.16448 PG 15 WC Physics, Condensed Matter SC Physics GA 274XX UT WOS:000084791300038 ER PT J AU Enachescu, M Schleef, D Ogletree, DF Salmeron, M AF Enachescu, M Schleef, D Ogletree, DF Salmeron, M TI Integration of point-contact microscopy and atomic-force microscopy: Application to characterization of graphite/Pt(111) SO PHYSICAL REVIEW B LA English DT Article ID SCANNING-TUNNELING MICROSCOPY; SURFACE FORCES; ADHESION; PT(111); CORRUGATIONS; IMAGES; LEED; STM AB The electrical current through the point-contact junction of an AFM tip is used to image the surfaces of bulk graphite (HOPG) and the surface of a graphitized carbon monolayer on Pt(111) under ultra-high-vacuum (UHV) conditions. Lattice-resolved images are obtained simultaneously in topography, lateral friction, and contact current channels. Lattice resolution in current maps persisted up to 0.9 mA and pressures of up to 5 GPa. In both bulk graphite and the case of graphitized carbon monolayer on Pt(111), the current images show only one maximum per unit cell. In addition, the contact current images of the graphite monolayer reveal local conductivity variations. We observed local conductivity variations in the form of moire superstructures resulting from high order commensurability with the Pt lattice. [S0163-1829(99)03248-8]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Bucharest, Dept Phys, Bucharest, Romania. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RP Salmeron, M (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. EM MBSalmeron@lbl.gov RI Enachescu, Marius/C-4963-2011; Ogletree, D Frank/D-9833-2016 OI Ogletree, D Frank/0000-0002-8159-0182 NR 34 TC 57 Z9 57 U1 2 U2 21 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 DEC 15 PY 1999 VL 60 IS 24 BP 16913 EP 16919 DI 10.1103/PhysRevB.60.16913 PG 7 WC Physics, Condensed Matter SC Physics GA 274XX UT WOS:000084791300091 ER PT J AU Hochstrasser, M Gilman, N Willis, RF Schumann, FO Tobin, JG Rotenberg, E AF Hochstrasser, M Gilman, N Willis, RF Schumann, FO Tobin, JG Rotenberg, E TI Photoemission study of Fermi surfaces of pseudomorphic Co, Ni, and CoxNi1-x films on Cu(100) SO PHYSICAL REVIEW B LA English DT Article ID MAGNETIC-BEHAVIOR; ULTRATHIN FILMS; EXCHANGE; LAYERS; LEVEL; OSCILLATIONS; INSTABILITY; GROWTH; NICKEL; PERIOD AB The k-space electronic structure of CoxNi1-x alloy films epitaxially grown on Cu(100) has been investigated with changing stoichiometry in angle-resolved photoemission, and is compared to the electronic structure of fee films of Co and Ni, and single-crystalline Cu. We have monitored changes in the Fermi surface with changing stoichiometry and changing magnetic behavior. The measurements show that the sp band is a prominent feature of the Fermi surface throughout k space for all of the alloys and the magnetic 3d pseudomorphic fee films. A band-structure calculation of Ni allows us to identify d-hole pockets which increase in size with changing stoichiometry. Minority spin states highlight specific regions of k space associated with key spanning vectors that determine the oscillatory exchange coupling, which underpins the giant magnetoresistance effect in heterostructures. [S0163-1829(99)03948-X]. C1 Penn State Univ, Dept Phys, University Pk, PA 16802 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Hochstrasser, M (reprint author), Penn State Univ, Dept Phys, 104 Davey Lab, University Pk, PA 16802 USA. RI Rotenberg, Eli/B-3700-2009; Schumann, Frank /K-9364-2014; Tobin, James/O-6953-2015 OI Rotenberg, Eli/0000-0002-3979-8844; NR 27 TC 13 Z9 13 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 DEC 15 PY 1999 VL 60 IS 24 BP 17030 EP 17036 DI 10.1103/PhysRevB.60.17030 PG 7 WC Physics, Condensed Matter SC Physics GA 274XX UT WOS:000084791300105 ER PT J AU Naumovic, D Aebi, P Schlapbach, L Beeli, C Lograsso, TA Delaney, DW AF Naumovic, D Aebi, P Schlapbach, L Beeli, C Lograsso, TA Delaney, DW TI Quasicrystalline nature of quasicrystal surfaces: A photoemission study SO PHYSICAL REVIEW B LA English DT Article ID PHOTOELECTRON-DIFFRACTION DATA; ICOSAHEDRAL QUASI-CRYSTALS; ELECTRONIC-STRUCTURE; FERMI-LEVEL; SPECTROSCOPY; AL68PD23MN9; HOLOGRAPHY; PSEUDOGAP; SYMMETRY; PHASE AB Differently prepared surfaces of quasicrystalline i-Al-Pd-Mn are analyzed using angle-resolved photoemission in the x-ray and ultraviolet range of photon energies. Depending on the preparation, we find both surfaces with crystalline structure and metallic character, and surfaces with quasicrystalline structural fingerprints and a suppressed density of states at the Fermi level, compatible with a pseudogap. [S0163-1829(99)51048-5]. C1 Univ Fribourg, Inst Phys, CH-1700 Fribourg, Switzerland. ETH Zentrum, Solid State Phys Lab, Zurich, Switzerland. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Naumovic, D (reprint author), Univ Fribourg, Inst Phys, Perolles, CH-1700 Fribourg, Switzerland. NR 32 TC 10 Z9 10 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 DEC 15 PY 1999 VL 60 IS 24 BP R16330 EP R16333 DI 10.1103/PhysRevB.60.R16330 PG 4 WC Physics, Condensed Matter SC Physics GA 274XX UT WOS:000084791300021 ER PT J AU Pesola, M von Boehm, J Sammalkorpi, V Mattila, T Nieminen, RM AF Pesola, M von Boehm, J Sammalkorpi, V Mattila, T Nieminen, RM TI Microscopic structure of oxygen defects in gallium arsenide SO PHYSICAL REVIEW B LA English DT Article ID SEMI-INSULATING GAAS; SUBSTITUTIONAL OXYGEN; MODE SPECTROSCOPY; ABSORPTION-BANDS; VACANCY COMPLEX; LOCAL MODE; AB-INITIO; PSEUDOPOTENTIALS; CENTERS AB Accurate total-energy pseudopotential methods an used to study the structures, binding energies, and local vibrational modes of various models for the Ga-O-Ga defect in GaAs. We find that the previously proposed models, O-As (an off-centered substitutional oxygen in arsenic vacancy) and O-.(1) (an oxygen atom occupying a tetrahedral interstitial site), are inconsistent with experimental data. We introduce a model, (As-Ga)(2)-O-As (two arsenic antisites and one off-centered substitutional oxygen in arsenic vacancy), the properties of which are in excellent agreement with experimental characterizations. [S0163-1829(99)51648-2]. C1 Aalto Univ, Phys Lab, FIN-02015 Espoo, Finland. Aalto Univ, LTAM, FIN-02015 Espoo, Finland. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Aalto Univ, Phys Lab, POB 1100, FIN-02015 Espoo, Finland. RI Nieminen, Risto/I-5573-2012 OI Nieminen, Risto/0000-0002-1032-2711 NR 29 TC 0 Z9 0 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 DEC 15 PY 1999 VL 60 IS 24 BP R16267 EP R16270 DI 10.1103/PhysRevB.60.R16267 PG 4 WC Physics, Condensed Matter SC Physics GA 274XX UT WOS:000084791300005 ER PT J AU Drukker, N Gross, DJ Ooguri, H AF Drukker, N Gross, DJ Ooguri, H TI Wilson loops and minimal surfaces SO PHYSICAL REVIEW D LA English DT Article ID EQUATION AB The AdS-CFT correspondence suggests that the Wilson loop of the large N gauge theory with N=4 supersymmetry in four dimensions is described by a minimal surface in AdS(5)XS(5). We examine various aspects of this proposal, comparing gauge theory expectations with computations of minimal surfaces. There is a distinguished class of loops, which we call BPS loops, whose expectation Values are free from ultraviolet divergence. We formulate the loop equation for such loops. To the extent that we have checked, the minimal surface in AdS(5)xS(5) gives a solution of the equation. We also discuss the zigzag symmetry of the loop operator. In the N=4 gauge theory, we expect the zigzag symmetry to hold when the loop does not couple the scalar fields in the supermultiplet. We will show how this is realized for the minimal surface. [S0556-2821(99)08718-4]. C1 Univ Calif Santa Barbara, Inst Theoret Phys, Santa Barbara, CA 93106 USA. Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Drukker, N (reprint author), Univ Calif Santa Barbara, Inst Theoret Phys, Santa Barbara, CA 93106 USA. EM drukker@itp.ucsb.edu; gross@itp.ucsb.edu; hooguri@lbl.gov RI Ooguri, Hirosi/A-4407-2011; OI Ooguri, Hirosi/0000-0001-6021-3778 NR 30 TC 302 Z9 302 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 DEC 15 PY 1999 VL 60 IS 12 AR 125006 DI 10.1103/PhysRevD.60.125006 PG 20 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 268PK UT WOS:000084424600042 ER PT J AU Kaplinghat, M Lopez, RE Dodelson, S Scherrer, RJ AF Kaplinghat, M Lopez, RE Dodelson, S Scherrer, RJ TI Improved treatment of cosmic microwave background fluctuations induced by a late-decaying massive neutrino SO PHYSICAL REVIEW D LA English DT Article ID DEGREE ANGULAR SCALES; ANISOTROPY MEASUREMENT; RADIATION; CONSTRAINTS; MATTER AB A massive neutrino which decays after recombination ((t greater than or equal to 10(13) sec) into relativistic decay products produces an enhanced integrated Sachs-Wolfe effect, allowing constraints to be placed on such neutrinos from present cosmic microwave background anisotropy data. Previous treatments of this problem have approximated the decay products as an additional component of the neutrino background. This approach violates energy-momentum conservation, and we show that it leads to serious errors for some neutrino masses and lifetimes. We redo this calculation more accurately, by correctly incorporating the spatial distribution of the decay products. For low neutrino masses and long lifetimes, we obtain a much smaller distortion in the CMB. fluctuation spectrum than have previous treatments. We combine these new results with a recent set of CMB data to exclude the mass and lifetime range m(h) > 100 eV, tau > 10(12) sec. Masses as low as 30 eV are excluded for a narrower range in Lifetime. [S0556-2821(99)04824-9]. C1 Ohio State Univ, Dept Phys, Columbus, OH 43210 USA. Univ Chicago, Enrico Fermi Inst, Dept Phys, Chicago, IL 60637 USA. Fermi Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. RP Kaplinghat, M (reprint author), Ohio State Univ, Dept Phys, Columbus, OH 43210 USA. NR 65 TC 37 Z9 37 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 DEC 15 PY 1999 VL 60 IS 12 AR 123508 DI 10.1103/PhysRevD.60.123508 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 268PK UT WOS:000084424600013 ER PT J AU Mungiole, M Pickle, LW Simonson, KH AF Mungiole, M Pickle, LW Simonson, KH TI Application of a weighted head-banging algorithm to mortality data maps SO STATISTICS IN MEDICINE LA English DT Article ID ROBUST AB Smoothed data maps permit the reader to identify general spatial trends by removing the background noise of random variability often present in raw data. To smooth mortality data from 798 small areas comprising the contiguous United States, we extended the head-banging algorithm to allow for differential weighting of the values to be smoothed. Actual and simulated data sets were used to determine how head-banging smoothed spike and edge features in the data, and to observe the degree to which weighting affected the results. As expected, spikes were generally removed while edges and clusters of high rates near the U.S. borders were maintained by the unweighted head-banging algorithm. Incorporating weights inversely proportional to standard errors had a substantial effect on smoothed data, for example determining whether observed spikes were retained or removed. The process used to obtain the smoothed data, including the choice of head-banging parameters, is discussed. Results are considered in the context of general spatial trends, 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 Ctr Dis Control & Prevent, Natl Ctr Hlth Stat, Hyattsville, MD 20782 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Mungiole, M (reprint author), USA, Res Lab, 2800 Powder Mill Rd, Adelphi, MD 20783 USA. NR 10 TC 40 Z9 40 U1 0 U2 1 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0277-6715 J9 STAT MED JI Stat. Med. PD DEC 15 PY 1999 VL 18 IS 23 BP 3201 EP + DI 10.1002/(SICI)1097-0258(19991215)18:23<3201::AID-SIM310>3.0.CO;2-U PG 14 WC Mathematical & Computational Biology; Public, Environmental & Occupational Health; Medical Informatics; Medicine, Research & Experimental; Statistics & Probability SC Mathematical & Computational Biology; Public, Environmental & Occupational Health; Medical Informatics; Research & Experimental Medicine; Mathematics GA 262QF UT WOS:000084077400005 PM 10602145 ER PT J AU Gelman, A Price, PN AF Gelman, A Price, PN TI All maps of parameter estimates are misleading SO STATISTICS IN MEDICINE LA English DT Article ID INDOOR RADON CONCENTRATIONS; EMPIRICAL BAYES METHODS; CANCER MORTALITY-RATES; VALUES; STATES; MODELS AB Maps are frequently used to display spatial distributions of parameters of interest, such as cancer rates or average pollutant concentrations by county. It is well known that plotting observed rates can have serious drawbacks when sample sizes vary by area, since very high (and low) observed rates are found disproportionately in poorly-sampled areas. Unfortunately, adjusting the observed rates to account for the effects of small-sample noise can introduce an opposite effect, in which the highest adjusted rates tend to be found disproportionately in well-sampled areas. In either case, the maps can be difficult to interpret because the display of spatial variation in the underlying parameters of interest is confounded with spatial variation in sample sizes. As a result, spatial patterns occur in adjusted rates even if there is no spatial structure in the underlying parameters of interest, and adjusted rates tend to look too uniform in areas with little data. We introduce two models (normal and Poisson) in which parameters of interest have no spatial patterns, and demonstrate the existence of spatial artefacts in inference from these models. We also discuss spatial models and the extent to which they are subject to the same artefacts. We present examples from Bayesian modelling, but, as we explain, the artefacts occur generally. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Columbia Univ, Dept Stat, New York, NY 10027 USA. RP Price, PN (reprint author), Lawrence Berkeley Natl Lab, LBNL 90-3058, Berkeley, CA 94720 USA. NR 27 TC 51 Z9 51 U1 1 U2 7 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0277-6715 J9 STAT MED JI Stat. Med. PD DEC 15 PY 1999 VL 18 IS 23 BP 3221 EP 3234 PG 14 WC Mathematical & Computational Biology; Public, Environmental & Occupational Health; Medical Informatics; Medicine, Research & Experimental; Statistics & Probability SC Mathematical & Computational Biology; Public, Environmental & Occupational Health; Medical Informatics; Research & Experimental Medicine; Mathematics GA 262QF UT WOS:000084077400007 PM 10602147 ER PT J AU Muller-Dieckmann, HJ Grantz, AA Kim, SH AF Muller-Dieckmann, HJ Grantz, AA Kim, SH TI The structure of the signal receiver domain of the Arabidopsis thaliana ethylene receptor ETR1 SO STRUCTURE WITH FOLDING & DESIGN LA English DT Article DE ethylene receptor; ethylene pathway in plants; ETR; signal transduction; two-component system ID BACTERIAL CHEMOTAXIS; RESPONSE REGULATOR; BACILLUS-SUBTILIS; ESCHERICHIA-COLI; PROTEIN; TRANSDUCTION; PHOSPHORYLATION; BINDING; CHEY; PATHWAY AB Background: In Arabidopsis thaliana, ethylene perception and signal transduction into the cell are carried out by a family of membrane-bound receptors, one of which is ethylene resistant 1 (ETR1). The large cytoplasmic domain of the receptor showed significant sequence homology to the proteins of a common bacterial regulatory pathway, the two-component system. This system consists of a transmitter histidine kinase and a response regulator (or signal receiver). We present the crystal structures of the first plant receiver domain ETRRD (residues 604-738) of ETR1 in two conformations. Results: The monomeric form of ETRRD resembles the known structure of the bacterial receiver domain. ETRRD forms a homodimer in solution and in the crystal, an interaction that has not been described previously. Dimerization is mediated by the C terminus, which forms an extended beta sheet with the dimer-related beta-strand core. Furthermore, the loop immediately following the active site adopts an exceptional conformation. Conclusions: The three-dimensional structure of ETRRD shows the expected conformational conservation to prokaryotic receiver proteins, such as CheY and CheB, both of which are part of the chemotaxis signaling pathway. ETRRD provides the first detailed example of a dimerized receiver domain. Given that the dimer interface of ETRRD coincides with the phosphorylation-dependent interfaces of CheY and CheB, we suggest that the monomerization of ETRRD is phosphorylation-dependent too. In the Mg2+-free form of ETRRD, the gamma-loop conformation does not allow a comparable interaction as observed in the active-site architectures of Mg2+-bound CheY from Escherichia coli and Salmonella typhimurium. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Dept Phyts Biochem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Phys Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Grad Grp Comparat Biochem, Berkeley, CA 94720 USA. RP Kim, SH (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Dept Phyts Biochem, Berkeley, CA 94720 USA. NR 55 TC 61 Z9 63 U1 1 U2 12 PU CURRENT BIOLOGY LTD PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 0969-2126 J9 STRUCT FOLD DES JI Struct. Fold. Des. PD DEC 15 PY 1999 VL 7 IS 12 BP 1547 EP 1556 DI 10.1016/S0969-2126(00)88345-8 PG 10 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 268TB UT WOS:000084430700013 PM 10647185 ER PT J AU Polley, TA Carter, WB Poker, DB AF Polley, TA Carter, WB Poker, DB TI Deposition of zinc oxide thin films by combustion CVD SO THIN SOLID FILMS LA English DT Article DE combustion chemical vapor deposition; zinc oxide ID CHEMICAL-VAPOR-DEPOSITION; ZNO FILMS; TEMPERATURE; GROWTH AB Combustion chemical vapor deposition (combustion CVD) has been developed to produce zinc oxide thin films. Combustion CVD is different from conventional CVD in that it is performed in a flame. The flame provides the energy, primarily in the form of heat, necessary to deposit ceramic thin films. Zinc 2-ethylhexanoate was dissolved in an organic solvent to produce the flammable solutions used to deposit zinc oxide films onto amorphous silica substrates. Zinc ion concentrations in the solutions were 0.01 M. Substrate temperatures were monitored and controlled during the depositions. Several substrate temperatures, ranging from 190-850 degrees C, were used. Crystalline films up to 1.4 mu m-thick were produced at deposition rates up to 5 mu m/h. The films were of the hexagonal wurtzite structure and displayed a strong preferred orientation of (002) normal to the substrate surfaces. A variety of microstructures were produced depending on substrate temperature during deposition. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction and Rutherford backscattering spectrometry were used to characterize the films. (C) 1999 Published by Elsevier Science S.A. All rights reserved. C1 Georgia Inst Technol, Sch Mat Sci & Engn, Atlanta, GA 30332 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Carter, WB (reprint author), Georgia Inst Technol, Sch Mat Sci & Engn, Atlanta, GA 30332 USA. NR 20 TC 25 Z9 41 U1 3 U2 8 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 DEC 15 PY 1999 VL 357 IS 2 BP 132 EP 136 DI 10.1016/S0040-6090(99)00646-X PG 5 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 270BG UT WOS:000084515100007 ER PT J AU Gao, YG Robinson, H Sanishvili, R Joachimiak, A Wang, AHJ AF Gao, YG Robinson, H Sanishvili, R Joachimiak, A Wang, AHJ TI Structure and recognition of sheared tandem G center dot A base pairs associated with human centromere DNA sequence at atomic resolution SO BIOCHEMISTRY LA English DT Article ID HAMMERHEAD RIBOZYME; CRYSTAL-STRUCTURE; RIBOSOMAL-RNA; B-DNA; MISMATCHES; STABILITY; DUPLEX; MOTIFS; REFINEMENT; BINDING AB G . A mismatched base pairs are frequently found in nucleic acids. Human centromere DNA sequences contain unusual repeating motifs, e.g., (GAATG)(n).(CATTC)(n), found in the human chromosome. The purine-rich strand of this repeating pentamer sequence forms duplex and hairpin structures with unusual stability. The high stability of these structures is contributed by the "sheared" G A base pairs which present a novel recognition surface for ligands and proteins. We have solved the crystal structure, by the multiple-wavelength anomalous diffraction (MAD) method of d(CCGAATGAGG) in which the centromere core sequence motif GAATG is embedded. Three crystal forms were refined to near-atomic resolution. The structures reveal the detailed conformation of tandem G A base pairs whose unique hydrogen-bonding surface has interesting interactions with bases, hydrated magnesium ions, cobalt(III)hexaammine, spermine, and water molecules. The results are relevant in understanding the structure associated with human centromere sequence in particular and G . A base pairs in nucleic acids (including RNA, like ribozyme) in general. C1 Univ Illinois, Dept Cell & Struct Biol, Urbana, IL 61801 USA. Argonne Natl Lab, Struct Biol Ctr, Biosci Div, Argonne, IL 60439 USA. Northwestern Univ, Dept Biochem Mol Biol & Cell Biol, Evanston, IL 60208 USA. RP Wang, AHJ (reprint author), Univ Illinois, Dept Cell & Struct Biol, Urbana, IL 61801 USA. FU NIGMS NIH HHS [GM41612] NR 49 TC 42 Z9 42 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 DEC 14 PY 1999 VL 38 IS 50 BP 16452 EP 16460 DI 10.1021/bi9914614 PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 266FE UT WOS:000084289300006 PM 10600106 ER PT J AU Paxson, V AF Paxson, V TI Bro: a system for detecting network intruders in real-time SO COMPUTER NETWORKS-THE INTERNATIONAL JOURNAL OF COMPUTER AND TELECOMMUNICATIONS NETWORKING LA English DT Article DE network intrusion detection; passive network monitoring; network monitoring evasion; domain-specific languages AB We describe Bro, a stand-alone system for detecting network intruders in real-time by passively monitoring a network link over which the intruder's traffic transits. We give an overview of the system's design, which emphasizes high-speed (FDDI-rate) monitoring, real-time notification, clear separation between mechanism and policy, and extensibility. To achieve these ends, Bro is divided into an 'event engine' that: reduces a kernel-filtered network traffic stream into a series of higher-level events, and a 'policy script interpreter' that interprets event handlers written in a specialized language used to express a site's security policy. Event handlers can update state information, synthesize new events, record information to disk, and generate real-time notifications via syslog. We also discuss a number of attacks that attempt to subvert passive monitoring systems and defenses against these, and give particulars of how Bro analyzes the six applications integrated into it so far: Finger, FTP, Portmapper, Ident, Telnet and Rlogin. The system is publicly available in source code form. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. AT&T Ctr Internet Res, ICSI, Berkeley, CA USA. RP Paxson, V (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RI Pagna Disso, Jules Ferdinand/A-6712-2009 OI Pagna Disso, Jules Ferdinand/0000-0001-8388-0418 NR 30 TC 499 Z9 534 U1 5 U2 22 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1389-1286 J9 COMPUT NETW JI Comput. Netw. PD DEC 14 PY 1999 VL 31 IS 23-24 BP 2435 EP 2463 DI 10.1016/S1389-1286(99)00112-7 PG 29 WC Computer Science, Hardware & Architecture; Computer Science, Information Systems; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA 275HJ UT WOS:000084814500002 ER PT J AU Smith, MD Green, PF Saunders, R AF Smith, MD Green, PF Saunders, R TI Anisochemical homopolymer/diblock copolymer thin film blends SO MACROMOLECULES LA English DT Article ID BINARY POLYMER MIXTURES; DIRECTED SPINODAL DECOMPOSITION; BISPHENOL-A POLYCARBONATE; BLOCK-COPOLYMER; DIBLOCK COPOLYMER; PHASE-SEPARATION; MOLECULAR-WEIGHT; ORDERED STRUCTURE; SURFACE SEGREGATION; BEHAVIOR AB We examined the effect of the addition of homopolymers tetramethylbisphenol A polycarbonate, TMPC, and poly(norbornene-methyl-d(3)-carboxylate), NBMC, on the interlamellar spacing and the phase stability of symmetric poly(styrene-b-methyl methacrylate) diblock copolymer thin films on silicon substrates. The films were of thickness h, L < h < 5L, where L is the interlamellar spacing of the microphase separated PS-b-PMMA diblock copolymer. The homopolymers considered had degrees of polymerization, N-TMPC and N-NBMC, comparable to one-half of the degree of polymerization of the diblock. In the TMPC/diblock blend, for low TMPC homopolymer concentrations, phi(TMPC) < 0.2, the homopolymer chains were localized in the middle of the PS micro-ordered domains, and the interlamellar spacing increased as L/(1 - phi(TMPC)). For phi(TMPC) > 0.2 the morphology of the diblock copolymer changed to accommodate higher volume fractions of TMPC. This behavior is contrasted with earlier observations in the PS-b-PMMA/PS homopolymer system where this diblock accommodated considerably higher PS homopolymer volume fractions while maintaining a lamellar phase. In the NBMC/diblock system the interlamellar spacing increased as L/(1 - phi(NBMC)) for homopolymer concentrations up to phi(NBMC) approximate to 0.05. For phi(NBMC) > 0.05, the NBMC formed a pure layer on the substrate, with the diblock maintaining its microphase separated structure on this layer. These results are discussed in light of mean field theory and in terms of the effect of the interfacial constraints on the phase behavior. C1 Univ Texas, Texas Mat Inst, Dept Chem Engn, Austin, TX 78712 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Green, PF (reprint author), Univ Texas, Texas Mat Inst, Dept Chem Engn, Austin, TX 78712 USA. NR 53 TC 17 Z9 17 U1 1 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 DEC 14 PY 1999 VL 32 IS 25 BP 8392 EP 8398 DI 10.1021/ma9908494 PG 7 WC Polymer Science SC Polymer Science GA 266ZC UT WOS:000084329300026 ER PT J AU Dickey, FM Holswade, SC Hornak, LA Brown, KS AF Dickey, FM Holswade, SC Hornak, LA Brown, KS TI Optical methods for micromachine monitoring and feedback SO SENSORS AND ACTUATORS A-PHYSICAL LA English DT Article DE micromachines; actuators; optical probe; feedback; performance analysis ID PERFORMANCE; MICROENGINE; SYSTEMS; FRICTION; MEMS; INTERCONNECTIONS; MOTION; PROBE AB Understanding the mechanisms that impact the performance of Microelectromechanical Systems (MEMS) is essential to the development of optimized designs and fabrication processes, as well as the qualification of devices for commercial applications. Silicon micromachines include engines that consist of orthogonally oriented linear comb drive actuators mechanically connected to a rotating gear. These gears are as small as 50 mu m in diameter and can be driven at rotation rates exceeding 300,000 rpm. Optical techniques offer the potential for measuring long term statistical performance data and transient responses needed to optimize designs and manufacturing techniques. Optical techniques can also be used to provide feedback signals needed for engine control and state determination. We describe the development of Micromachine Optical Probe (MOP) technology for the evaluation of micromachine performance. The MOP approach is based on the detection of optical signals scattered by the gear teeth or other physical structures. We present experimental results for a prototype system designed to measure engine parameters as well as long term performance data. We also present the extension of the MOP technique to LIGA-fabricated milliengines. Concepts and technologies for the development of integrated micromachine metrology are detailed. This work is targeted at enabling routine use of optical feedback at the microelectromechanical device level for MEMS optimal control and lifetime monitoring. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. W Virginia Univ, Dept Comp Sci & Elect Engn, Microelect Syst Res Ctr, Morgantown, WV 26506 USA. RP Dickey, FM (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 46 TC 17 Z9 18 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0924-4247 J9 SENSOR ACTUAT A-PHYS JI Sens. Actuator A-Phys. PD DEC 14 PY 1999 VL 78 IS 2-3 BP 220 EP 235 DI 10.1016/S0924-4247(99)00207-1 PG 16 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 269WK UT WOS:000084500400023 ER PT J AU Datskos, PG Sauers, I AF Datskos, PG Sauers, I TI Detection of 2-mercaptoethanol using gold-coated micromachined cantilevers SO SENSORS AND ACTUATORS B-CHEMICAL LA English DT Article DE mercaptans; microcantilever; molecular adsorption; resonance frequency; bimaterial bending ID QUARTZ CRYSTAL MICROBALANCE; ADSORPTION; SENSORS; MICROCANTILEVERS; STRESS AB We have measured the response of gold-coated silicon nitride microcantilevers to 2-mercaptoethanol (HS-CH2-CH2-OH) vapors and found that they respond rather sensitively to 2-mercaptoethanol vapors. Such microcantilevers can be used to develop sensitive micromechanical chemical sensors for detecting sulfur-containing compounds. Microcantilevers with a gold coating on one side respond to adsorption of molecules by changes in their resonance frequency and/or bending. The bending induced from adsorption of 2-mercaptoethanol molecules on microcantilevers is at least an order of magnitude more sensitive than any corresponding resonance frequency changes resulting from mass loading. In the present studies, we used the adsorption-induced bending and placed a lower limit in the minimum detectable concentration of mercaptan vapor at < 50 parts per billion (ppb). (C) 1999 Elsevier Science S.A. All rights reserved. C1 Oak Ridge Natl Lab, Engn Technol Div, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. RP Datskos, PG (reprint author), Oak Ridge Natl Lab, Engn Technol Div, MS 8039,POB 2009, Oak Ridge, TN 37831 USA. NR 25 TC 60 Z9 61 U1 2 U2 10 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 DEC 14 PY 1999 VL 61 IS 1-3 BP 75 EP 82 DI 10.1016/S0925-4005(99)00251-8 PG 8 WC Chemistry, Analytical; Electrochemistry; Instruments & Instrumentation SC Chemistry; Electrochemistry; Instruments & Instrumentation GA 273PX UT WOS:000084717000012 ER PT J AU Serkland, DK Choquette, KD Hadley, GR Geib, KM Allerman, AA AF Serkland, DK Choquette, KD Hadley, GR Geib, KM Allerman, AA TI Two-element phased array of antiguided vertical-cavity lasers SO APPLIED PHYSICS LETTERS LA English DT Article ID SURFACE-EMITTING LASER; LOCKED ARRAYS; DISCRIMINATION; OPERATION AB We demonstrate antiguided coupling of two adjacent vertical-cavity surface-emitting lasers (VCSELs), obtaining a 1x2 phase-locked array at 869 nm. The lateral index modification required for antiguiding is achieved by a patterned 3 nm etch performed between two epitaxial growths. In contrast with prior coupled VCSELs, adjacent antiguided VCSELs can emit in phase and produce a single on-axis lobe in the far field. Greater than 2 mW of in-phase output power is demonstrated with two VCSELs separated by 8 mu m. Moreover, phase locking of two VCSELs separated by 20 mu m is observed, indicating the possibility of a promising class of optical circuits based upon VCSELs that interact horizontally and emit vertically. (C) 1999 American Institute of Physics. [S0003-6951(99)04050-4]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Serkland, DK (reprint author), Sandia Natl Labs, POB 5800,MS 0603, Albuquerque, NM 87185 USA. NR 12 TC 56 Z9 56 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 DEC 13 PY 1999 VL 75 IS 24 BP 3754 EP 3756 DI 10.1063/1.125445 PG 3 WC Physics, Applied SC Physics GA 265KF UT WOS:000084242600006 ER PT J AU Record, KA Palmieri, DR Haegel, NM Wynne, D AF Record, KA Palmieri, DR Haegel, NM Wynne, D TI Imaging near-contact transport in the planar-collector geometry for a Schottky contact on high-purity GaAs SO APPLIED PHYSICS LETTERS LA English DT Article ID DIFFUSION-LENGTH AB Variable temperature electron beam induced current (EBIC) and cathodoluminescence (CL) were combined to image electric fields and charge transport for a Schottky contact on high purity epitaxial GaAs in the planar-collector geometry. Simultaneous EBIC and CL imaging proves that the near-contact EBIC signal is dominated by depletion effects, even in material where the bulk diffusion length greatly exceeds the intercontact distance. In forward bias, an EBIC dipole is observed, providing direct spatial indication of the transition between drift and diffusion transport of locally generated charge. (C) 1999 American Institute of Physics. [S0003-6951(99)00150-3]. C1 Fairfield Univ, Dept Phys, Fairfield, CT 06430 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. RP Haegel, NM (reprint author), Fairfield Univ, Dept Phys, Fairfield, CT 06430 USA. NR 16 TC 4 Z9 4 U1 0 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 DEC 13 PY 1999 VL 75 IS 24 BP 3829 EP 3831 DI 10.1063/1.125470 PG 3 WC Physics, Applied SC Physics GA 265KF UT WOS:000084242600031 ER PT J AU Carlson, CM Parilla, PA Siegal, MP Ginley, DS Wang, YT Blaugher, RD Price, JC Overmyer, DL Venturini, EL AF Carlson, CM Parilla, PA Siegal, MP Ginley, DS Wang, YT Blaugher, RD Price, JC Overmyer, DL Venturini, EL TI LaNiO3 buffer layers for high critical current density YBa2Cu3O7-delta and Tl2Ba2CaCu2O8-delta films (vol 75, pg 2479, 1999) SO APPLIED PHYSICS LETTERS LA English DT Correction C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Carlson, CM (reprint author), Univ Colorado, Dept Phys, Boulder, CO 80309 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 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 DEC 13 PY 1999 VL 75 IS 24 BP 3886 EP 3886 DI 10.1063/1.124249 PG 1 WC Physics, Applied SC Physics GA 265KF UT WOS:000084242600050 ER PT J AU McCleskey, TM Burns, CJ Tumas, W AF McCleskey, TM Burns, CJ Tumas, W TI Uranyl photochemistry with alkenes: Distinguishing between H-atom abstraction and electron transfer SO INORGANIC CHEMISTRY LA English DT Article ID TRANSITION-METAL COMPLEXES; ORGANIC-COMPOUNDS; EXCITED-STATES; HYDROCARBONS; OXIDATION; IONS; ENERGIES; OXYGEN AB Uranyl Photochemistry with Alkenes: Distinguishing between H-Atom Abstraction and Electron Transfer We have studied the quenching of the uranyl ion in aqueous acetonitrile with a series of alkenes. The quenching rate constant (k(q)) increases linearly with decreasing ionization potential (IP) for a series of hexene isomers, as seen in a plot of In (k(q)) vs IP; no correlation is observed between the quenching rate and the bond dissociation energy of the allylic C-H bond. These results demonstrate that the mechanism of quenching for alkenes is electron transfer from the alkene to uranyl. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP McCleskey, TM (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI McCleskey, Thomas/J-4772-2012; OI Mccleskey, Thomas/0000-0003-3750-3245 NR 24 TC 27 Z9 28 U1 1 U2 5 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 DEC 13 PY 1999 VL 38 IS 25 BP 5924 EP + DI 10.1021/ic9909126 PG 3 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 265LF UT WOS:000084245200046 ER PT J AU Thorning, M AF Thorning, M TI How climate change policy could shrink the federal budget surplus and stifle US economic growth SO OIL & GAS JOURNAL LA English DT Article C1 Amer Council Capital Format, Ctr Policy Res, Washington, DC 20006 USA. US DOE, Washington, DC 20585 USA. US Dept Commerce, Washington, DC 20230 USA. Fed Trade Commiss, Washington, DC 20580 USA. RP Thorning, M (reprint author), Amer Council Capital Format, Ctr Policy Res, Washington, DC 20006 USA. NR 17 TC 0 Z9 0 U1 0 U2 1 PU PENNWELL PUBL CO ENERGY GROUP PI TULSA PA 1421 S SHERIDAN RD PO BOX 1260, TULSA, OK 74101 USA SN 0030-1388 J9 OIL GAS J JI Oil Gas J. PD DEC 13 PY 1999 VL 97 IS 50 BP 22 EP 26 PG 5 WC Energy & Fuels; Engineering, Petroleum SC Energy & Fuels; Engineering GA 264ZY UT WOS:000084214800004 ER PT J AU Rose, B AF Rose, B TI Consolidation, changing core competencies alter offshore drilling responsibilities SO OIL & GAS JOURNAL LA English DT Article C1 Global Marine Inc, Houston, TX 77210 USA. US DOE, Natl Petr Council, Washington, DC 20585 USA. Amer Bur Shipping, New York, NY 10048 USA. Amer Petr Inst, Washington, DC USA. RP Rose, B (reprint author), Global Marine Inc, Houston, TX 77210 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU PENNWELL PUBL CO ENERGY GROUP PI TULSA PA 1421 S SHERIDAN RD PO BOX 1260, TULSA, OK 74101 USA SN 0030-1388 J9 OIL GAS J JI Oil Gas J. PD DEC 13 PY 1999 VL 97 IS 50 BP 52 EP + PG 3 WC Energy & Fuels; Engineering, Petroleum SC Energy & Fuels; Engineering GA 264ZY UT WOS:000084214800009 ER PT J AU Kagan, AL Neubert, M AF Kagan, AL Neubert, M TI Large Delta I=3/2 contribution to epsilon '/epsilon in supersymmetry SO PHYSICAL REVIEW LETTERS LA English DT Article ID CHANGING NEUTRAL CURRENTS; CP-VIOLATION; CONSTRAINTS AB We show that in supersymmetric extensions of the standard model gluino box diagrams can yield a large CP-violating Delta I = 3/2 contribution to s --> d (q) over bar q flavor-changing neutral current processes, which feeds into the I = 2 isospin amplitude in K --> pi pi decays. This contribution requires only moderate mass splitting between the right-handed squarks (u) over tilde(R) and (d) over tilde(R) and persists for squark masses of order 1 TeV. Taking into account current bounds from K-(K) over bar mixing, the reulting contribution to epsilon(1)/epsilon could naturally be an order of magnitude larger than the measured value. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Kagan, AL (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 26 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 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD DEC 13 PY 1999 VL 83 IS 24 BP 4929 EP 4932 DI 10.1103/PhysRevLett.83.4929 PG 4 WC Physics, Multidisciplinary SC Physics GA 263YC UT WOS:000084152000006 ER PT J AU Abbott, B Abolins, M Abramov, V Acharya, BS Adam, I Adams, DL Adams, M Ahn, S Alves, GA Amos, N Anderson, EW Baarmand, MM Babintsev, VV Babukhadia, L Baden, A Baldin, B Banerjee, S Bantly, J Barberis, E Baringer, P Bartlett, JF Belyaev, A Beri, SB Bertram, I Bezzubov, VA Bhat, PC Bhatnagar, V Bhattacharjee, M Biswas, N Blazey, G Blessing, S Bloom, P Boehnlein, A Bojko, NI Borcherding, F Boswell, C Brandt, A Breedon, R Briskin, G Brock, R Bross, A Buchholz, D Burtovoi, VS Butler, JM Carvalho, W Casey, D Casilum, Z Castilla-Valdez, H Chakraborty, D Chekulaev, SV Chen, W Choi, S Chopra, S Choudhary, BC Christenson, JH Chung, M Claes, D Clark, AR Cobau, WG Cochran, J Coney, L Cooper, WE Coppage, D Cretsinger, C Cullen-Vidal, D Cummings, MAC Cutts, D Dahl, OI Davis, K De, K Del Signore, K Demarteau, M Denisov, D Denisov, SP Diehl, HT Diesburg, M Di Loreto, G Draper, P Ducros, Y Dudko, LV Dugad, SR Dyshkant, A Edmunds, D Ellison, J Elvira, VD Engelmann, R Eno, S Eppley, G Ermolov, P Eroshin, OV Evdokimov, VN Fahland, T Fatyga, MK Feher, S Fein, D Ferbel, T Fisk, HE Fisyak, Y Flattum, E Forden, GE Fortner, M Frame, KC Fuess, S Gallas, E Galyaev, AN Gartung, P Gavrilov, V Geld, TL Genik, RJ Genser, K Gerber, CE Gershtein, Y Gibbard, B Gobbi, B Gomez, B Gomez, G Goncharov, PI Solis, JLG Gordon, H Goss, LT Gounder, K Goussiou, A Graf, N Grannis, PD Green, DR Greenlee, H Grinstein, S Grudberg, P Grunendahl, S Guglielmo, G Guida, JA Guida, JM Gupta, A Gurzhiev, SN Gutierrez, G Gutierrez, P Hadley, NJ Haggerty, H Hagopian, S Hagopian, V Hahn, KS Hall, RE Hanlet, P Hansen, S Hauptman, JM Hebert, C Hedin, D Heinson, AP Heintz, U Hernandez-Montoya, R Heuring, T Hirosky, R Hobbs, JD Hoeneisen, B Hoftun, JS Hsieh, F Hu, T Ito, AS Jaques, J Jerger, SA Jesik, R Joffe-Minor, T Johns, K Johnson, M Jonckheere, A Jones, M Jostlein, H Jun, SY Jung, CK Kahn, S Kalbfleisch, G Karmanov, D Karmgard, D Kehoe, R Kim, SK Klima, B Klopfenstein, C Ko, W Kohli, JM Koltick, D Kostritskiy, AV Kotcher, J Kotwal, AV Kozelov, AV Kozlovsky, EA Krane, J Krishnaswamy, MR Krzywdzinski, S Kuleshov, S Kulik, Y Kunori, S Landry, F Landsberg, G Lauer, B Leflat, A Li, J Li, QZ Lima, JGR Lincoln, D Linn, SL Linnemann, J Lipton, R Lobkowicz, F Lucotte, A Lueking, L Lyon, AL Maciel, AKA Madaras, RJ Madden, R Magana-Mendoza, L Manankov, V Mani, S Mao, HS Markeloff, R Marshall, T Martin, MI Mauritz, KM May, B Mayorov, AA McCarthy, R McDonald, J McKibben, T McKinley, J McMahon, T Melanson, HL Merkin, M Merritt, KW Miao, C Miettinen, H Mincer, A Mishra, CS Mokhov, N Mondal, NK Montgomery, HE Mooney, P Mostafa, M da Motta, H Murphy, C Nang, F Narain, M Narasimham, VS Narayanan, A Neal, HA Negret, JP Nemethy, P Norman, D Oesch, L Oguri, V Oshima, N Owen, D Padley, P Para, A Parashar, N Park, YM Partridge, R Parua, N Paterno, M Pawlik, B Perkins, J Peters, M Piegaia, R Piekarz, H Pischalnikov, Y Pope, BG Prosper, HB Protopopescu, S Qian, J Quintas, PZ Raja, R Rajagopalan, S Ramirez, O Reucroft, S Rijssenbeek, M Rockwell, T Roco, M Rubinov, P Ruchti, R Rutherfoord, J Sanchez-Hernandez, A Santoro, A Sawyer, L Schamberger, RD Schellman, H Sculli, J Shabalina, E Shaffer, C Shankar, HC Shivpuri, RK Shpakov, D Shupe, M Singh, H Singh, JB Sirotenko, V Smith, E Smith, RP Snihur, R Snow, GR Snow, J Snyder, S Solomon, J Sosebee, M Sotnikova, N Souza, M Steinbruck, G Stephens, RW Stevenson, ML Stichelbaut, F Stoker, D Stolin, V Stoyanova, DA Strauss, M Streets, K Strovink, M Sznajder, A Tamburello, P Tarazi, J Tartaglia, M Thomas, TLT Thompson, J Trippe, TG Tuts, PM Vaniev, V Varelas, N Varnes, EW Volkov, AA Vorobiev, AP Wahl, HD Wang, G Warchol, J Watts, G Wayne, M Weerts, H White, A White, JT Wightman, JA Willis, S Wimpenny, SJ Wirjawan, JVD Womersley, J Won, E Wood, DR Wu, Z Yamada, R Yamin, P Yasuda, T Yepes, P Yip, K Yoshikawa, C Youssef, S Yu, J Yu, Y Zhang, B Zhou, Z Zhu, ZH Zielinski, M Zieminska, D Zieminski, A Zverev, EG Zylberstejn, A AF Abbott, B Abolins, M Abramov, V Acharya, BS Adam, I Adams, DL Adams, M Ahn, S Alves, GA Amos, N Anderson, EW Baarmand, MM Babintsev, VV Babukhadia, L Baden, A Baldin, B Banerjee, S Bantly, J Barberis, E Baringer, P Bartlett, JF Belyaev, A Beri, SB Bertram, I Bezzubov, VA Bhat, PC Bhatnagar, V Bhattacharjee, M Biswas, N Blazey, G Blessing, S Bloom, P Boehnlein, A Bojko, NI Borcherding, F Boswell, C Brandt, A Breedon, R Briskin, G Brock, R Bross, A Buchholz, D Burtovoi, VS Butler, JM Carvalho, W Casey, D Casilum, Z Castilla-Valdez, H Chakraborty, D Chekulaev, SV Chen, W Choi, S Chopra, S Choudhary, BC Christenson, JH Chung, M Claes, D Clark, AR Cobau, WG Cochran, J Coney, L Cooper, WE Coppage, D Cretsinger, C Cullen-Vidal, D Cummings, MAC Cutts, D Dahl, OI Davis, K De, K Del Signore, K Demarteau, M Denisov, D Denisov, SP Diehl, HT Diesburg, M Di Loreto, G Draper, P Ducros, Y Dudko, LV Dugad, SR Dyshkant, A Edmunds, D Ellison, J Elvira, VD Engelmann, R Eno, S Eppley, G Ermolov, P Eroshin, OV Evdokimov, VN Fahland, T Fatyga, MK Feher, S Fein, D Ferbel, T Fisk, HE Fisyak, Y Flattum, E Forden, GE Fortner, M Frame, KC Fuess, S Gallas, E Galyaev, AN Gartung, P Gavrilov, V Geld, TL Genik, RJ Genser, K Gerber, CE Gershtein, Y Gibbard, B Gobbi, B Gomez, B Gomez, G Goncharov, PI Solis, JLG Gordon, H Goss, LT Gounder, K Goussiou, A Graf, N Grannis, PD Green, DR Greenlee, H Grinstein, S Grudberg, P Grunendahl, S Guglielmo, G Guida, JA Guida, JM Gupta, A Gurzhiev, SN Gutierrez, G Gutierrez, P Hadley, NJ Haggerty, H Hagopian, S Hagopian, V Hahn, KS Hall, RE Hanlet, P Hansen, S Hauptman, JM Hebert, C Hedin, D Heinson, AP Heintz, U Hernandez-Montoya, R Heuring, T Hirosky, R Hobbs, JD Hoeneisen, B Hoftun, JS Hsieh, F Hu, T Ito, AS Jaques, J Jerger, SA Jesik, R Joffe-Minor, T Johns, K Johnson, M Jonckheere, A Jones, M Jostlein, H Jun, SY Jung, CK Kahn, S Kalbfleisch, G Karmanov, D Karmgard, D Kehoe, R Kim, SK Klima, B Klopfenstein, C Ko, W Kohli, JM Koltick, D Kostritskiy, AV Kotcher, J Kotwal, AV Kozelov, AV Kozlovsky, EA Krane, J Krishnaswamy, MR Krzywdzinski, S Kuleshov, S Kulik, Y Kunori, S Landry, F Landsberg, G Lauer, B Leflat, A Li, J Li, QZ Lima, JGR Lincoln, D Linn, SL Linnemann, J Lipton, R Lobkowicz, F Lucotte, A Lueking, L Lyon, AL Maciel, AKA Madaras, RJ Madden, R Magana-Mendoza, L Manankov, V Mani, S Mao, HS Markeloff, R Marshall, T Martin, MI Mauritz, KM May, B Mayorov, AA McCarthy, R McDonald, J McKibben, T McKinley, J McMahon, T Melanson, HL Merkin, M Merritt, KW Miao, C Miettinen, H Mincer, A Mishra, CS Mokhov, N Mondal, NK Montgomery, HE Mooney, P Mostafa, M da Motta, H Murphy, C Nang, F Narain, M Narasimham, VS Narayanan, A Neal, HA Negret, JP Nemethy, P Norman, D Oesch, L Oguri, V Oshima, N Owen, D Padley, P Para, A Parashar, N Park, YM Partridge, R Parua, N Paterno, M Pawlik, B Perkins, J Peters, M Piegaia, R Piekarz, H Pischalnikov, Y Pope, BG Prosper, HB Protopopescu, S Qian, J Quintas, PZ Raja, R Rajagopalan, S Ramirez, O Reucroft, S Rijssenbeek, M Rockwell, T Roco, M Rubinov, P Ruchti, R Rutherfoord, J Sanchez-Hernandez, A Santoro, A Sawyer, L Schamberger, RD Schellman, H Sculli, J Shabalina, E Shaffer, C Shankar, HC Shivpuri, RK Shpakov, D Shupe, M Singh, H Singh, JB Sirotenko, V Smith, E Smith, RP Snihur, R Snow, GR Snow, J Snyder, S Solomon, J Sosebee, M Sotnikova, N Souza, M Steinbruck, G Stephens, RW Stevenson, ML Stichelbaut, F Stoker, D Stolin, V Stoyanova, DA Strauss, M Streets, K Strovink, M Sznajder, A Tamburello, P Tarazi, J Tartaglia, M Thomas, TLT Thompson, J Trippe, TG Tuts, PM Vaniev, V Varelas, N Varnes, EW Volkov, AA Vorobiev, AP Wahl, HD Wang, G Warchol, J Watts, G Wayne, M Weerts, H White, A White, JT Wightman, JA Willis, S Wimpenny, SJ Wirjawan, JVD Womersley, J Won, E Wood, DR Wu, Z Yamada, R Yamin, P Yasuda, T Yepes, P Yip, K Yoshikawa, C Youssef, S Yu, J Yu, Y Zhang, B Zhou, Z Zhu, ZH Zielinski, M Zieminska, D Zieminski, A Zverev, EG Zylberstejn, A CA D0 Collaboration TI Search for squarks and gluinos in events containing jets and a large imbalance in transverse energy SO PHYSICAL REVIEW LETTERS LA English DT Article ID FERMILAB TEVATRON COLLIDER; SUPERSYMMETRIC PARTICLES; P(P)OVER-BAR COLLISIONS; HADRON COLLIDERS; ROOT-S=1.8 TEV; SUPERGRAVITY; BREAKING; DECAYS AB Using data corresponding to an integrated luminosity of 79 pb(-1), D0 has searched for events containing multiple jets and large missing transverse energy in p (p) over bar collisions at root s = 1.8 TeV at the Fermilab Tevatron collider. Observing no significant excess beyond what is expected from the standard model, we set limits on the masses of squarks and gluinos and on the model parameters m(0) and m(1/2), in the framework of the minimal low-energy supergravity models of supersymmetry. For tan beta = 2 and A(0) = 0, with mu < 0, we exclude all models with m(q) < 250 GeV/c(2). For models with equal squark and gluino masses, we exclude m < 260 GeV/c(2). C1 Univ Buenos Aires, Buenos Aires, DF, Argentina. Ctr Brasileiro Pesquisas Fis, LAFEX, Rio De Janeiro, Brazil. Univ Estado Rio de Janeiro, Rio De Janeiro, Brazil. Univ Los Andes, Bogota, Colombia. CEA, Serv Phys Particules, DAPNIA, Saclay, France. Panjab Univ, Chandigarh 160014, India. Univ Delhi, Delhi 110007, India. Tata Inst Fundamental Res, Mumbai, India. Kyungsung Univ, Pusan 608736, South Korea. Seoul Natl Univ, Seoul, South Korea. CINVESTAV, Mexico City 14000, DF, Mexico. Inst Nucl Phys, Krakow, Poland. Inst Theoret & Expt Phys, Moscow 117259, Russia. Moscow State Univ, Moscow, Russia. Inst High Energy Phys, Protvino, Russia. Univ Arizona, Tucson, AZ 85721 USA. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Berkeley, CA 94720 USA. Univ Calif Davis, Davis, CA 95616 USA. Univ Calif Irvine, Irvine, CA 92697 USA. Univ Calif Riverside, Riverside, CA 92521 USA. Florida State Univ, Tallahassee, FL 32306 USA. Univ Hawaii, Honolulu, HI 96822 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Illinois, Chicago, IL 60607 USA. No Illinois Univ, De Kalb, IL 60115 USA. Northwestern Univ, Evanston, IL 60208 USA. Indiana Univ, Bloomington, IN 47405 USA. Univ Notre Dame, Notre Dame, IN 46556 USA. Purdue Univ, W Lafayette, IN 47907 USA. Iowa State Univ, Ames, IA 50011 USA. Univ Kansas, Lawrence, KS 66045 USA. Louisiana Tech Univ, Ruston, LA 71272 USA. Univ Maryland, College Pk, MD 20742 USA. Boston Univ, Boston, MA 02215 USA. Northeastern Univ, Boston, MA 02115 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Michigan State Univ, E Lansing, MI 48824 USA. Univ Nebraska, Lincoln, NE 68588 USA. Columbia Univ, New York, NY 10027 USA. NYU, New York, NY 10003 USA. Univ Rochester, Rochester, NY 14627 USA. SUNY Stony Brook, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Langston Univ, Langston, OK 73050 USA. Univ Oklahoma, Norman, OK 73019 USA. Brown Univ, Providence, RI 02912 USA. Univ Texas, Arlington, TX 76019 USA. Texas A&M Univ, College Stn, TX 77843 USA. Rice Univ, Houston, TX 77005 USA. RP Abbott, B (reprint author), Univ Buenos Aires, Buenos Aires, DF, Argentina. RI Sznajder, Andre/L-1621-2016; Yip, Kin/D-6860-2013; Kuleshov, Sergey/D-9940-2013; De, Kaushik/N-1953-2013; Oguri, Vitor/B-5403-2013; Alves, Gilvan/C-4007-2013; Belyaev, Alexander/F-6637-2015; Kim, Sun Kee/G-2042-2015; Chekulaev, Sergey/O-1145-2015; Shivpuri, R K/A-5848-2010; Gutierrez, Phillip/C-1161-2011; Dudko, Lev/D-7127-2012; Leflat, Alexander/D-7284-2012; Merkin, Mikhail/D-6809-2012 OI Sznajder, Andre/0000-0001-6998-1108; Baarmand, Marc/0000-0002-9792-8619; Yip, Kin/0000-0002-8576-4311; Kuleshov, Sergey/0000-0002-3065-326X; De, Kaushik/0000-0002-5647-4489; Belyaev, Alexander/0000-0002-1733-4408; Kim, Sun Kee/0000-0002-0013-0775; Dudko, Lev/0000-0002-4462-3192; NR 31 TC 60 Z9 60 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 DEC 13 PY 1999 VL 83 IS 24 BP 4937 EP 4942 DI 10.1103/PhysRevLett.83.4937 PG 6 WC Physics, Multidisciplinary SC Physics GA 263YC UT WOS:000084152000008 ER PT J AU Vaitaitis, A Drucker, RB Formaggio, J Koutsoliotas, S Adams, T Alton, A Avvakumov, S de Barbaro, L de Barbaro, P Bernstein, RH Bodek, A Bolton, T Brau, J Buchholz, D Budd, H Bugel, L Conrad, J Fleming, BT Frey, R Goldman, J Goncharov, M Harris, DA Johnson, RA Kim, JH Lamm, MJ Marsh, W Mason, D McFarland, KS McNulty, C Monroe, J Naples, D Nienaber, P Romosan, A Sakumoto, WK Schellman, H Shaevitz, MH Spentzouris, P Stern, EG Vakili, M Wu, V Yang, UK Yu, J Zeller, GP Zimmerman, ED AF Vaitaitis, A Drucker, RB Formaggio, J Koutsoliotas, S Adams, T Alton, A Avvakumov, S de Barbaro, L de Barbaro, P Bernstein, RH Bodek, A Bolton, T Brau, J Buchholz, D Budd, H Bugel, L Conrad, J Fleming, BT Frey, R Goldman, J Goncharov, M Harris, DA Johnson, RA Kim, JH Lamm, MJ Marsh, W Mason, D McFarland, KS McNulty, C Monroe, J Naples, D Nienaber, P Romosan, A Sakumoto, WK Schellman, H Shaevitz, MH Spentzouris, P Stern, EG Vakili, M Wu, V Yang, UK Yu, J Zeller, GP Zimmerman, ED TI Search for neutral heavy leptons in a high-energy neutrino beam SO PHYSICAL REVIEW LETTERS LA English DT Article ID DECAYS; SCATTERING AB A search for neutral heavy leptons (NHLs) has:been performed using an instrumented decay channel at the NuTeV (E-815) experiment at Fermilab. The data were examined for NHLs decaying into muonic final states (mu mu v, mu ev, mu pi, and mu p); no evidence has been found for NHLs in the 0.25-2.0 GeV mass range. This analysis places limits on the mixing of NHLs with standard light neutrinos at a level up to an order of magnitude more restrictive than previous search limits in this mass range. C1 Univ Cincinnati, Cincinnati, OH 45221 USA. Columbia Univ, New York, NY 10027 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Kansas State Univ, Manhattan, KS 66506 USA. Northwestern Univ, Evanston, IL 60208 USA. Univ Oregon, Eugene, OR 97403 USA. Univ Rochester, Rochester, NY 14627 USA. RP Vaitaitis, A (reprint author), Univ Cincinnati, Cincinnati, OH 45221 USA. RI Frey, Raymond/E-2830-2016; OI Frey, Raymond/0000-0003-0341-2636; Bernstein, Robert/0000-0002-7610-950X NR 17 TC 58 Z9 58 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 DEC 13 PY 1999 VL 83 IS 24 BP 4943 EP 4946 DI 10.1103/PhysRevLett.83.4943 PG 4 WC Physics, Multidisciplinary SC Physics GA 263YC UT WOS:000084152000009 ER PT J AU Hansen, CT Wilks, SC Young, PE AF Hansen, CT Wilks, SC Young, PE TI Spectral evidence for collisionless absorption in subpicosecond laser-solid interactions SO PHYSICAL REVIEW LETTERS LA English DT Article ID RESONANT ABSORPTION; PLASMAS; PULSES; GENERATION; TARGETS AB Second-harmonic emission produced by the interaction of a 130-fs laser pulse with solid aluminum has been spectrally analyzed. For an angle of incidence near 20 degrees, the specular second harmonic is blueshifted when the laser intensity exceeds 5 x 10(16) W/cm(2). This effect is also observed in particle-in-cell simulations of the experiment. The blueshift is interpreted as a signature of the onset of absorption due to the anomalous skin effect. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Hansen, CT (reprint author), Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94550 USA. NR 18 TC 22 Z9 23 U1 0 U2 1 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 DEC 13 PY 1999 VL 83 IS 24 BP 5019 EP 5022 DI 10.1103/PhysRevLett.83.5019 PG 4 WC Physics, Multidisciplinary SC Physics GA 263YC UT WOS:000084152000028 ER PT J AU McEuen, PL Bockrath, M Cobden, DH Yoon, YG Louie, SG AF McEuen, PL Bockrath, M Cobden, DH Yoon, YG Louie, SG TI Disorder, pseudospins, and backscattering in carbon nanotubes SO PHYSICAL REVIEW LETTERS LA English DT Article ID SINGLE-WALL; BACK SCATTERING; QUANTUM WIRES; TRANSPORT; ABSENCE AB We address the effects of disorder on the conducting properties of metal and semiconducting carbon nanotubes. Experimentally, the mean free path is found to be much larger in metallic tubes than in doped semiconducting tubes. We show that this result can be understood theoretically if the disorder potential is long ranged. The effects of a pseudospin index that describes the internal sublattice structure of the states lead to a suppression of scattering in metallic tubes, but not in semiconducting tubes. This conclusion is supported by tight-binding calculations. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP McEuen, PL (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Yoon, Young-Gui/C-2978-2008 OI Yoon, Young-Gui/0000-0002-1071-8628 NR 21 TC 335 Z9 338 U1 2 U2 31 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 DEC 13 PY 1999 VL 83 IS 24 BP 5098 EP 5101 DI 10.1103/PhysRevLett.83.5098 PG 4 WC Physics, Multidisciplinary SC Physics GA 263YC UT WOS:000084152000048 ER PT J AU Lorenzana, J Eroles, J Sorella, S AF Lorenzana, J Eroles, J Sorella, S TI Does the Heisenberg model describe the multimagnon spin dynamics in antiferromagnetic CuO layers? SO PHYSICAL REVIEW LETTERS LA English DT Article ID LAMELLAR COPPER OXIDES; 2-MAGNON RAMAN-SCATTERING; CYCLIC 4-SPIN EXCHANGE; OPTICAL-ABSORPTION; QUANTUM ANTIFERROMAGNETS; HUBBARD-MODEL; EXCITATIONS; FLUCTUATIONS; TEMPERATURE; INSULATORS AB We compute the absorption spectrum for multimagnon excitations assisted by phonons in insulating layered cuprates using exact diagonalization in clusters of up to 32 sites. The resulting line shape is very sensitive to the underlying magnetic Hamiltonian describing the spin dynamics. For the usual Heisenberg description of undoped Cu-O planes we find, in accordance with experiment, a two-magnon peak followed by high energy sidebands. However the relative weight of the sidebands is too small to reproduce the experiment. An extended Heisenberg model including a sizable four-site cyclic exchange term is shown to be consistent with the experimental data. C1 Univ Rome La Sapienza, Dipartimento Fis, Ist Nazl Fis Mat, I-00185 Rome, Italy. Ctr Atom Bariloche, RA-8400 Bariloche, Rio Negro, Argentina. Inst Balseiro, RA-8400 Bariloche, Rio Negro, Argentina. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. SISSA, Ist Nazl Fis Mat, I-34014 Trieste, Italy. RP Lorenzana, J (reprint author), Univ Rome La Sapienza, Dipartimento Fis, Ist Nazl Fis Mat, Piazzale A Moro 2, I-00185 Rome, Italy. RI Lorenzana, Jose/A-2809-2008 OI Lorenzana, Jose/0000-0001-7426-2570 NR 29 TC 60 Z9 60 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 DEC 13 PY 1999 VL 83 IS 24 BP 5122 EP 5125 DI 10.1103/PhysRevLett.83.5122 PG 4 WC Physics, Multidisciplinary SC Physics GA 263YC UT WOS:000084152000054 ER PT J AU Klintenberg, M AF Klintenberg, M TI On the Coulomb operator for embedded cluster calculations in periodic systems SO PHYSICS LETTERS A LA English DT Article DE Coulomb operator; embedded cluster; periodic systems AB In performing ab-initio or DFT embedded cluster calculations in infinite periodic systems one unsolved problem is how to embed the quantum cluster in the general case. We show that the Ewald real space sum can be implemented as an operator in the Hamiltonian when the reciprocal space sum is made small. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Klintenberg, M (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, 1 Cyclotron Rd 55-121, Berkeley, CA 94720 USA. NR 12 TC 0 Z9 0 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD DEC 13 PY 1999 VL 264 IS 1 BP 57 EP 62 DI 10.1016/S0375-9601(99)00767-7 PG 6 WC Physics, Multidisciplinary SC Physics GA 270CA UT WOS:000084516800009 ER PT J AU Assamagan, KA Buck, WW Chen, SY Ent, R Green, RN Gueye, P Keppel, C Mourou, G Umstadter, D Wagner, R AF Assamagan, KA Buck, WW Chen, SY Ent, R Green, RN Gueye, P Keppel, C Mourou, G Umstadter, D Wagner, R TI Electron beam characteristics of a laser-driven plasma wakefield accelerator SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB The properties of an electron beam trapped and accelerated in a laser wakefield have been investigated. Plastic scintillating fibers were employed together with position sensitive photomultiplier tubes (PMT) and a series of dipole electro-magnets to study the beam. The measured momentum spectrum peaks around 7 MeV/c with an exponential fall-off at high moments up to (70.3 +/- 19.9) MeV/c. The number of electrons detected per bunch is determined to be (2.6 +/- 0.3) x 10(11). (C) 1999 Elsevier Science B.V. All rights reserved. C1 Hampton Univ, Nucl High Energy Phys Res Ctr, Dept Phys, Hampton, VA 23668 USA. Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. Univ Michigan, Ctr Ultrafast Opt Sci, Ann Arbor, MI 48109 USA. RP Assamagan, KA (reprint author), CERN, Div EP, CH-1211 Geneva 23, Switzerland. RI Chen, Szu-yuan/F-7555-2012; Umstadter, Donald/A-1581-2016 OI Umstadter, Donald/0000-0002-2182-4346 NR 6 TC 3 Z9 3 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 DEC 11 PY 1999 VL 438 IS 2-3 BP 265 EP 276 DI 10.1016/S0168-9002(99)00882-7 PG 12 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 265RH UT WOS:000084256800004 ER PT J AU Shigaki, K Akiba, Y Chasman, C Chen, Z Hamagaki, H Kumagai, A Kurita, K Miake, Y Sako, H Sasaki, O Ueno-Hayashi, S Wegner, HE Zhu, F AF Shigaki, K Akiba, Y Chasman, C Chen, Z Hamagaki, H Kumagai, A Kurita, K Miake, Y Sako, H Sasaki, O Ueno-Hayashi, S Wegner, HE Zhu, F CA Forward Spectrometer Team BNL-AGS TI A forward magnetic spectrometer system for high-energy heavy-ion experiments SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE magnetic spectrometer; relativistic heavy-ion collision; tracking chambers; particle identification ID TIME PROJECTION CHAMBER; SI+A COLLISIONS; ANTIPROTON PRODUCTION; PARTICLE-PRODUCTION; AU+AU COLLISIONS; GEV/C; DENSITY AB A small aperture magnetic spectrometer has been built to study hadron production in Au-197 + Au-197 collisions at the AGS energy of 11.6A GeV/c. It operates in the forward angular range from 6 to 30 degrees with respect to the incident beam axis and covers the mid-rapidity region for heavy particles such as protons. The detector components of the spectrometer system include two time projection chambers, four drift chamber modules and a time-of-flight scintillation counter wall. A few new technologies are implemented in the design of the system to achieve the performance goals. The spectrometer has proved to function properly under the high particle-density environment encountered in experiments with the heavy-ion colliding system. The achieved momentum resolution is 1.3% in r.m.s. for pions at 1 GeV/c and 1.6% for protons at the same momentum. With the time-of-flight resolution of 76 ps in r.m.s., the particle identification momentum limit extends to 4 GeV/c for pions, 3 GeV/c for kaons, 5 GeV/c for protons, and 4.5 GeV/c for anti-protons. The tracking efficiency stays above 86% for tracks up to 5 GeV/c with as many as 10 tracks in the spectrometer aperture. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Tokyo, Dept Phys, Tokyo 1130033, Japan. Univ Tokyo, Inst Nucl Study, Tokyo 1880002, Japan. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Univ Tsukuba, Inst Phys, Tsukuba, Ibaraki 3058571, Japan. KEK, Tsukuba, Ibaraki 3050801, Japan. RP Shigaki, K (reprint author), KEK, Tsukuba, Ibaraki 3050801, Japan. RI HAMAGAKI, HIDEKI/G-4899-2014 NR 28 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 DEC 11 PY 1999 VL 438 IS 2-3 BP 282 EP 301 DI 10.1016/S0168-9002(99)00680-4 PG 20 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 265RH UT WOS:000084256800006 ER PT J AU Snellings, RJM Hulsbergen, W Prendergast, EP van den Brink, A de Haas, AP Habets, JJLM Kamermans, R Koopmans, M Kuijer, PG de Laat, CTAM Ostendorf, RW Peghaire, A Rossewij, M AF Snellings, RJM Hulsbergen, W Prendergast, EP van den Brink, A de Haas, AP Habets, JJLM Kamermans, R Koopmans, M Kuijer, PG de Laat, CTAM Ostendorf, RW Peghaire, A Rossewij, M TI An analytic solution for energy loss and time-of-flight calculations for intermediate-energy light ions SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE Bethe-Bloch formula; intermediate energies; Birks' law; Huygens detector ID READ-OUT; DETECTOR AB Particle identification in intermediate heavy-ion collisions, using a modern 4 pi detector which contains several active layers, relies on a parametrisation or numerical integration of the energy loss in thick layers of detector material for different ions. Here an analytical solution applicable over an energy range of a few MeV up to a 100A MeV and for ions up to at least Z = 8 is presented. Also, the consequences for time-of-flight measurements (TOF) in detectors behind several thick layers of detector material are discussed. The solution is applied to the data of the Huygens detector, which uses a TPC (dE/dx) and plastic scintillators for particle identification(E and TOF or dE/dx and TOF). (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Utrecht, Dept Subatom Phys, NIKHEF, Vakgrp Subatom Fys, NL-3508 TA Utrecht, Netherlands. LBNL, Berkeley, CA 94720 USA. Kernfys Versneller Inst, NL-9747 AA Groningen, Netherlands. GANIL, F-14021 Caen, France. RP Kamermans, R (reprint author), Univ Utrecht, Dept Subatom Phys, NIKHEF, Vakgrp Subatom Fys, POB 80-000, NL-3508 TA Utrecht, Netherlands. NR 18 TC 0 Z9 0 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 DEC 11 PY 1999 VL 438 IS 2-3 BP 368 EP 375 DI 10.1016/S0168-9002(99)00804-9 PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 265RH UT WOS:000084256800015 ER PT J AU Job, PK Pisharody, M Semones, E AF Job, PK Pisharody, M Semones, E TI Measurement of absorbed dose by 7-GeV bremsstrahlung in a PMMA phantom SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID ELECTRON STORAGE-RINGS; GAS BREMSSTRAHLUNG AB High-energy electron storage rings generate energetic bremsstrahlung photons through radiative interaction of the particle beam with the residual gas molecules and other components inside the storage ring. At synchrotron radiation facilities, where beamlines are channeled out of the storage ring, a continuous bremsstrahlung spectrum, with a maximum energy of the stored particle beam, will be present. At the advanced photon source (APS), where the stored beam energy is 7 GeV, bremsstrahlung generated in the straight sections of the insertion device beamlines, which are a total of 15.38 m in length, can be significant. The contribution from each bremsstrahlung interaction adds up to produce a narrow mono-directional bremsstrahlung beam that comes down through the insertion device beamlines. The resulting absorbed dose distributions by this radiation in a 300 mm x 300 mm x 300 mm tissue substitute cube phantom were measured with LiF:Mg,Ti (TLD-700) thermoluminescent dosemeters. The normalized absorbed dose, in a cross-sectional area of 100 mm(2) at a depth of 150 mm of the PMMA phantom, was measured as 3.3 x 10(6) mGy h(-1)W(-1) for 7-GeV bremsstrahlung spectrum. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Adv Photon Source, Expt Facil Div, Argonne, IL 60439 USA. RP Job, PK (reprint author), Argonne Natl Lab, Adv Photon Source, Expt Facil Div, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 13 TC 4 Z9 4 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 DEC 11 PY 1999 VL 438 IS 2-3 BP 540 EP 547 DI 10.1016/S0168-9002(99)00806-2 PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 265RH UT WOS:000084256800030 ER PT J AU Chang, SY Apichartpiyakul, C Kuiken, CL Essex, M Lee, TH AF Chang, SY Apichartpiyakul, C Kuiken, CL Essex, M Lee, TH TI Sequence features downstream of the primer-binding site of HIV type 1 subtype E shared by subtype G and a subset of subtype A SO AIDS RESEARCH AND HUMAN RETROVIRUSES LA English DT Article ID HUMAN-IMMUNODEFICIENCY-VIRUS; THAILAND AB Two distinct sequence features downstream of the primer-binding site (PBS) were identified in a full-length HIV-1 subtype E clone amplified in this study. Both features are frequently found in HIV-1 subtypes A and G and in more than half of the full-length intersubtype recombinant clones. One of these is the absence of a trinucleotide sequence, which is located 14 nucleotides downstream of the PBS and found only in subtypes B, C, D, F, and H. The other is an insertion of 24 nucleotides immediately downstream of the PBS, which was previously reported as a sequence feature shared by subtypes A, E, and G, The analysis conducted here revealed that this 24-nucleotide insertion contained two sequence motifs duplicated in adjacent regions and was not found in all HIV-1 subtype A clones, Furthermore, our finding suggests that the PBS region of all known full-length subtype E clones, which are A/E intersubtype recombinants, is derived from the group of HIV-1 subtype A, which contains a similar insertion. C1 Harvard Univ, Sch Publ Hlth, Dept Immunol & Infect Dis, Boston, MA 02115 USA. Chiang Mai Univ, Fac Med, Dept Microbiol, Chiang Mai 50002, Thailand. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Lee, TH (reprint author), Harvard Univ, Sch Publ Hlth, Dept Immunol & Infect Dis, 651 Huntington Ave, Boston, MA 02115 USA. FU FIC NIH HHS [D43 TW 00004-10]; NCI NIH HHS [CA-39805] NR 8 TC 10 Z9 11 U1 0 U2 0 PU MARY ANN LIEBERT INC PUBL PI LARCHMONT PA 2 MADISON AVENUE, LARCHMONT, NY 10538 USA SN 0889-2229 J9 AIDS RES HUM RETROV JI Aids Res. Hum. Retrovir. PD DEC 10 PY 1999 VL 15 IS 18 BP 1703 EP 1706 DI 10.1089/088922299309748 PG 4 WC Immunology; Infectious Diseases; Virology SC Immunology; Infectious Diseases; Virology GA 263VV UT WOS:000084146700043 PM 10606093 ER PT J AU Naulleau, PP Goldberg, KA Lee, SH Chang, C Attwood, D Bokor, J AF Naulleau, PP Goldberg, KA Lee, SH Chang, C Attwood, D Bokor, J TI Extreme-ultraviolet phase-shifting point-diffraction interferometer: a wave-front metrology tool with subangstrom reference-wave accuracy SO APPLIED OPTICS LA English DT Article ID AT-WAVELENGTH INTERFEROMETRY; LITHOGRAPHY; RADIATION; OPTICS; SYSTEM AB The phase-shifting point-diffraction interferometer (PS/PDI) was recently developed and implemented at Lawrence Berkeley National Laboratory to characterize extreme-ultraviolet (EUV) projection optical systems for lithography. Here we quantitatively characterize the accuracy and precision of the PS/PDI. Experimental measurements are compared with theoretical results. Two major classes of errors affect the accuracy of the interferometer: systematic effects arising from measurement geometry and systematic and random errors due to an imperfect reference wave. To characterize these effects, and hence to calibrate the interferometer, a null test is used. This null test also serves as a measure of the accuracy of the interferometer. We show the EUV PS/PDI, as currently implemented, to have a systematic error-limited reference-wave accuracy of 0.0028 waves (lambda/357 or 0.038 mo at lambda = 13.5 nm) within a numerical aperture of 0.082. (C) 1999 Optical Society of America. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Elect Engn & Comp Sci, Berkeley, CA 94720 USA. RP Naulleau, PP (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. EM pnaulleau@lbl.gov RI Bokor, Jeffrey/A-2683-2011 NR 16 TC 73 Z9 81 U1 2 U2 13 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 DEC 10 PY 1999 VL 38 IS 35 BP 7252 EP 7263 DI 10.1364/AO.38.007252 PG 12 WC Optics SC Optics GA 265CA UT WOS:000084222500010 PM 18324274 ER PT J AU Scoccimarro, R Zaldarriaga, M Hui, L AF Scoccimarro, R Zaldarriaga, M Hui, L TI Power spectrum correlations induced by nonlinear clustering SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : clusters : general; large-scale structure of universe; methods : numerical; methods : statistical ID LARGE-SCALE STRUCTURE; REDSHIFT SURVEYS; COSMOLOGICAL PERTURBATIONS; FLUCTUATIONS; EVOLUTION; STATISTICS; GALAXIES AB Gravitational clustering is an intrinsically nonlinear process that generates significant non-Gaussian signatures in the density field. We consider how these affect power spectrum determinations from galaxy and weak-lensing surveys. Non-Gaussian effects not only increase the individual error bars compared to the Gaussian case but, most importantly, lead to nontrivial cross-correlations between different band powers, correlating small-scale band powers both among themselves and with those at large scales. We calculate the power-spectrum covariance matrix in nonlinear perturbation theory (weakly nonlinear regime), in the hierarchical model (strongly nonlinear regime), and from numerical simulations in real and redshift space. In particular, we show that the hierarchical Ansatz cannot be strictly valid for the configurations of the trispectrum involved in the calculation of the power-spectrum covariance matrix. We discuss the impact of these results on parameter estimation from power-spectrum measurements and their dependence on the size of the survey and the choice of band powers. We show that the non-Gaussian terms in the covariance matrix become dominant for scales smaller than the nonlinear scale k(nl) similar to 0.2 h(-1) Mpc(-1), depending somewhat on power normalization. Furthermore, we find that crosscorrelations mostly deteriorate the determination of the amplitude of a rescaled power spectrum, whereas its shape is less affected. In weak lensing surveys the projection tends to reduce the importance of non-Gaussian effects. Even so, for background galaxies at redshift z similar to 1, the non-Gaussian contribution rises significantly around l similar to 1000 and could become comparable to the Gaussian terms depending upon the power spectrum normalization and cosmology. The projection has another interesting effect: the ratio between non-Gaussian and Gaussian contributions saturates and can even decrease at small enough angular scales if the power spectrum of the three-dimensional field falls faster than k(-2). C1 CITA, McLennan Phys Labs, Toronto, ON M5S 3H8, Canada. Inst Adv Study, Sch Nat Sci, Princeton, NJ 08540 USA. NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Scoccimarro, R (reprint author), CITA, McLennan Phys Labs, 60 St George St, Toronto, ON M5S 3H8, Canada. NR 34 TC 116 Z9 116 U1 1 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 DEC 10 PY 1999 VL 527 IS 1 BP 1 EP 15 DI 10.1086/308059 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 265EA UT WOS:000084227300001 ER PT J AU Krokidis, X Moriarty, NW Lester, WA Frenklach, M AF Krokidis, X Moriarty, NW Lester, WA Frenklach, M TI Propargyl radical: an electron localization function study SO CHEMICAL PHYSICS LETTERS LA English DT Article ID TOPOLOGICAL ANALYSIS; BONDS; APPROXIMATION; SPECTROSCOPY; POTENTIALS; ALLENE; H2CCCH; ATOMS AB Bonding in the C3H3 radical has been determined using the topological analysis of the electron localization function (ELF) calculated with various wavefunctions (HF, LSDA, MP?, CASSCF, QCISD, BLYP, B3LYP). Not only is ELF independent of quantum chemical approximation, but also produced topologically equivalent molecular partitions. The ELF partition of space into localization domains provides an objective characterization of bonding in C3H3, supporting a resonance description of almost equal contributions of propargyl and allenyl forms. Moreover, it explains the reported difference between the frequencies of the in-plane and out-of-plane bending modes ( suggest a tendency to follow RSHP. Most significantly, the scaling exponent of <(delta(r)theta\(chi r,epsilon r))over bar> over epsilon(r) was shown to be approximately -1/6 in the inertial subrange, confirming a dynamical aspect of RSHP. In agreement with recent experimental results (Zhu et al. 1995; Stolovitzky et al. 1995), the probability distributions of the random variable beta(s) = delta(r)theta\(chi r,epsilon r)/(chi(r)(1/2) epsilon(r)(-1/6) r(1/3)) were found to be nearly Gaussian. However, contrary to the experimental results, we find that the moments of beta(s) are almost identical to those for the velocity field found in Part 1 of this study (Wang et al. 1996) and are insensitive to Reynolds number, large-scale forcing, and subgrid modelling. C1 Univ Delaware, Dept Mech Engn, Spencer Lab 126, Newark, DE 19716 USA. Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Penn State Univ, Dept Mech Engn, University Pk, PA 16802 USA. RP Wang, LP (reprint author), Univ Delaware, Dept Mech Engn, Spencer Lab 126, Newark, DE 19716 USA. EM lwang@me.udel.edu RI Chen, Shiyi/A-3234-2010; Wang, Lian-Ping/N-7516-2016 OI Wang, Lian-Ping/0000-0003-4276-0051 NR 68 TC 42 Z9 42 U1 0 U2 8 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD DEC 10 PY 1999 VL 400 BP 163 EP 197 DI 10.1017/S0022112099006448 PG 35 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 265CL UT WOS:000084223600006 ER PT J AU Trewhella, J Parkin, DM AF Trewhella, J Parkin, DM TI A day in the World Science Alliance SO SCIENCE LA English DT Editorial Material C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Trewhella, J (reprint author), Univ Calif Los Alamos Natl Lab, Mail Stop G758, Los Alamos, NM 87545 USA. OI Trewhella, Jill/0000-0002-8555-6766 NR 0 TC 0 Z9 0 U1 0 U2 1 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 DEC 10 PY 1999 VL 286 IS 5447 BP 2104 EP 2106 DI 10.1126/science.286.5447.2104 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 264AK UT WOS:000084157300039 ER PT J AU Andel, F Ladurner, AG Inouye, C Tjian, R Nogales, E AF Andel, F Ladurner, AG Inouye, C Tjian, R Nogales, E TI Three-dimensional structure of the human TFIID-IIA-IIB complex SO SCIENCE LA English DT Article ID RNA-POLYMERASE-II; TATA-BINDING-PROTEIN; MEDIATE TRANSCRIPTIONAL ACTIVATION; YEAST TFIIA/TBP/DNA COMPLEX; CRYSTAL-STRUCTURE; PROMOTER SELECTIVITY; IN-VITRO; COACTIVATOR; INITIATION; DROSOPHILA AB The multisubunit transcription factor IID (TFIID) is an essential component of the eukaryotic RNA polymerase II machinery that works in concert with TFIIA (IIA) and TFIIB (IIB) to assemble initiation complexes at core eukaryotic promoters. Here the structures of human TFIID and the TFIID-IIA-IIB complex that were obtained by electron microscopy and image analysis to 35 angstrom resolution are presented. TFIID is a trilobed, horseshoe-shaped structure, with TFIIA and TFIIB bound on opposite Lobes and flanking a central cavity. Antibody studies Locate the TATA-binding protein (TBP) between TFIIA and TFIIB at the top of the cavity that most Likely encompasses the TATA DNA binding region of the supramolecular complex. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mol & Cellular Biol, Berkeley, CA 94720 USA. Univ Calif Berkeley, Howard Hughes Med Inst, Berkeley, CA 94720 USA. RP Nogales, E (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. NR 47 TC 96 Z9 97 U1 0 U2 0 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 DEC 10 PY 1999 VL 286 IS 5447 BP 2153 EP 2156 DI 10.1126/science.286.5447.2153 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 264AK UT WOS:000084157300051 PM 10591646 ER PT J AU Lee, B AF Lee, B TI First-order system least-squares for elliptic problems with robin boundary conditions SO SIAM JOURNAL ON NUMERICAL ANALYSIS LA English DT Article DE first-order system least-squares; Robin boundary conditions; multigrid; preconditioning ID FINITE-ELEMENT METHOD; ONE INNER-PRODUCT; STOKES EQUATIONS AB This paper studies a least-squares approach to scalar second-order elliptic partial differential equations with Robin boundary conditions. As in several earlier papers by Bramble, Lazarov, and Pasciak [Math. Comp., 66 (1997), pp. 935-955]; Cai et al. [SIAM J. Numer Anal., 31 (1994), pp. 1785-1799]; Cai, Manteuffel, and McCormick [SIAM J. Numer. Anal., 34 (1997), pp. 425-454, 1727-1741]; Chang [SIAM J. Numer Anal., 29 (1992), pp. 452-461]; and Jiang and Povinelli [Comput. Methods Appl. Mech. Engrg., 102 (1993), pp. 199-212], the scalar equation is first recast into a first-order system by introducing velocity or flux variables, where some norm is then applied to the residual of this system to create a least-squares functional. We show here that a least-squares principle based on an L-2 norm produces optimal discretization error estimates in the H-1 norm for all variables in the system. We further show that a least-squares principle based on a combination of L-2 and H-1 norms yields optimal discretization error in a corresponding combination of H-1 and L-2 norms for the variables. Finally, a regularity result for the L-2 least-squares formulation and numerical examples for both formulations are given. C1 L661 Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, Livermore, CA 94550 USA. RP Lee, B (reprint author), L661 Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, Livermore, CA 94550 USA. NR 27 TC 4 Z9 4 U1 0 U2 1 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 0036-1429 J9 SIAM J NUMER ANAL JI SIAM J. Numer. Anal. PD DEC 10 PY 1999 VL 37 IS 1 BP 70 EP 104 DI 10.1137/S0036142997325313 PG 35 WC Mathematics, Applied SC Mathematics GA 273JM UT WOS:000084704200005 ER PT J AU Ahdjoudj, J Martinsky, C Minot, C Van Hove, MA Somorjai, GA AF Ahdjoudj, J Martinsky, C Minot, C Van Hove, MA Somorjai, GA TI Theoretical study of the termination of the Fe3O4 (111) surface SO SURFACE SCIENCE LA English DT Article DE CRYSTAL; iron oxide; polar surface; relaxation; UHF ID IRON-OXIDE FILMS; SCANNING-TUNNELING-MICROSCOPY; ELECTRONIC-STRUCTURE; CRYSTAL SURFACES; TOTAL-ENERGY; PT(111); ALPHA-FE2O3; STABILITY; GROWTH; PSEUDOPOTENTIALS AB Ab-initio periodic Hartree-Fock calculations for the structure of the (111) surface of Fe3O4 (magnetite) are presented. The slabs that are derived by an ideal bulk truncation that leaves one or two iron monolayers outside oxygen layers are found to be more stable than others since they preserve most of the coordination of the surface atoms. The stability of the slabs that represent the surface layers depends on the overall composition, specifically on the deviation from stoichiometry, and on the dipole moment perpendicular to the surface. The symmetrical slab with the layer sequence Fe2O4Fe3O4Fe2, terminated on each side by iron bilayers, is the best compromise since symmetry insures the neutrality of the dipole moment. This slab is oxygen-deficient. The energetically preferred structure relaxes so that one of the two outermost iron layers moves toward the slab center plane, exchanging sequence with the oxygen layer. The slab with the layer sequence FeO4Fe3O4Fe, which is also symmetric, is terminated by iron single monolayers, would represent an excessive oxidation of the iron atoms. This slab may be reduced by hydrogenation; it is then strongly stabilized and the vertical displacement of the oxygen atoms agrees with the structure determined by LEED (the LEED study would not have detected hydrogen). (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Paris 06, Chim Theor Lab, CNRS, UMR 7616, F-75252 Paris 05, France. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Minot, C (reprint author), Univ Paris 06, Chim Theor Lab, CNRS, UMR 7616, Tour 23-22,Boite 137, F-75252 Paris 05, France. EM minot@lct.jussieu.fr RI Van Hove, Michel/A-9862-2008 OI Van Hove, Michel/0000-0002-8898-6921 NR 60 TC 46 Z9 47 U1 1 U2 32 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD DEC 10 PY 1999 VL 443 IS 1-2 BP 133 EP 153 DI 10.1016/S0039-6028(99)01008-0 PG 21 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 267XW UT WOS:000084385400017 ER PT J AU Keller, GR Hatcher, RD AF Keller, GR Hatcher, RD TI Some comparisons of the structure and evolution of the southern Appalachian-Ouachita orogen and portions of the Trans-European Suture Zone region SO TECTONOPHYSICS LA English DT Article; Proceedings Paper CT XXIIIrd Annual Meeting of the European-Geophysical-Society CY 1998 CL NICE, FRANCE SP European Geophys Soc DE structure; tectonics; geophysics; Appalachian-Ouachita orogen; Trans-European suture zone ID SOUTHEASTERN UNITED-STATES; GRENVILLE BASEMENT BENEATH; COAST MAGNETIC-ANOMALIES; NEW-ENGLAND APPALACHIANS; CRUSTAL STRUCTURE; SEISMIC-REFLECTION; NORTHERN APPALACHIANS; CONTINENTAL-MARGIN; GRAVITY-ANOMALIES; DEEP-STRUCTURE AB Many aspects of the tectonic history of the Appalachian-Ouachita orogen and the Trans-European suture region are similar. In a tectonic sense, they are geographically linked, because at the end of the Paleozoic, one could travel from Texas to Poland following a continuous orogenic belt. Much of each of these orogenic belts is, however, buried by younger strata, and thus geophysical studies are a key element of efforts to better understand them. Many more geophysical data are needed to provide a comprehensive picture of the deep structure, but in several areas new models of the lithospheric structure are emerging. In this paper, we review some of these models and introduce two new ones for the southern Appalachians. In addition, we explore the implications of these models for the evolution of these orogenic belts, drawing attention to similarities and differences in their structure and evolution. The Appalachian and Caledonian orogens represent temporally parallel development along irregular Late Proterozoic continental mal:gins, but the crustal structure is different because of different accretionary elements and complications in the geometry of the original margins. Lateral transport via thrusting can confuse efforts to tie geologic structures identified on the surface with deep structures. For example, in the Appalachian-Ouachita orogen, the thrust-related transport distance for major features such as the Blue Ridge-Piedmont sheet and the Benton uplift is at least 200 km, On a crustal scale, deformation in the Appalachian-Ouachita orogen varies greatly in style and intensity. In the Ouachita orogen, the Late Proterozoic continental margin seems to be preserved, while in the northern Appalachians crustal-scale deformation is intense. Along the US Appalachians, the major crustal structure variation is the thin, dense crust of Avalonia abutting the relatively thick crust of Laurentia. Along the Ouachita orogen, several large crustal blocks can be identified that are unlike anything seen along the Appalachians. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Texas, Dept Geol Sci, El Paso, TX 79968 USA. Univ Tennessee, Dept Geol Sci, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Keller, GR (reprint author), Univ Texas, Dept Geol Sci, El Paso, TX 79968 USA. NR 144 TC 36 Z9 38 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0040-1951 J9 TECTONOPHYSICS JI Tectonophysics PD DEC 10 PY 1999 VL 314 IS 1-3 BP 43 EP 68 DI 10.1016/S0040-1951(99)00236-X PG 26 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 284XB UT WOS:000085357200004 ER PT J AU Goods, SH Neuschwanger, CL Whinnery, LL Nix, WD AF Goods, SH Neuschwanger, CL Whinnery, LL Nix, WD TI Mechanical properties of a particle-strengthened polyurethane foam SO JOURNAL OF APPLIED POLYMER SCIENCE LA English DT Article DE mechanical properties; foam; particle-strengthening; modulus ID COMPOSITES AB Quasi-static compression tests have been performed on polyurethane foam specimens. The modulus of the foam exhibited a power-law dependence with respect to density of the form: E* proportional to (rho*)(n), where n = 1.7. The modulus data are described well by a simple geometric model (based on the work of Gibson and Ashby) for a closed-cell foam in which the stiffness of the foam is governed by the flexure of the cell struts and cell walls. The compressive strength of the foam is also found to follow a power-law behavior with respect to foam density. In this instance, Euler buckling is used to explain the density dependence. The modulus of the foam was modified by addition of gas-atomized, spherical, aluminum powder. Additions of 30 and 50 wt % Al measurably increased the foam modulus, but without a change in the density dependence. However, there was no observable increase in modulus with 5 and 10 wt % additions of the metal powder. Strength was also increased at high loading fractions of powder. The increase in modulus and strength could be predicted by combining the Gibson-Ashby model, referred to above, with a well-known model describing the effect on modulus of a rigid dispersoid in a compliant matrix. (C) 1999 John Wiley & Sons, Inc. C1 Sandia Natl Labs, Livermore, CA 94550 USA. Hewlett Packard Co, Palo Alto, CA 94304 USA. Stanford Univ, Dept Mat Sci & Engn, Stanford, CA 94350 USA. RP Goods, SH (reprint author), Sandia Natl Labs, Livermore, CA 94550 USA. NR 26 TC 54 Z9 63 U1 1 U2 30 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 DEC 9 PY 1999 VL 74 IS 11 BP 2724 EP 2736 DI 10.1002/(SICI)1097-4628(19991209)74:11<2724::AID-APP20>3.0.CO;2-1 PG 13 WC Polymer Science SC Polymer Science GA 243MU UT WOS:000083002500020 ER PT J AU Guo, Y Thompson, DL Miller, WH AF Guo, Y Thompson, DL Miller, WH TI Thermal and microcanonical rates of unimolecular reactions from an energy diffusion theory approach SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID DISSOCIATION; MOLECULES; DYNAMICS; KRAMERS; RDX AB We present an energy diffusion theory approach for computing thermal and microcanonical unimolecular reaction rates by solving the general energy diffusion equation. The solution naturally provides the rates in the diffusion limit for fast reactions and the transition state theory (TST) limit for slow reactions. The reaction rates between the two limits can be easily obtained by solving a one-dimensional Schrodinger-like equation transformed from the diffusion equation. Employing a model system consisting of a set of harmonic oscillators interacting with a heat bath, the thermal rates from the low-temperature TST regime to the high-temperature diffusion regime are calculated to demonstrate their dependence on the size of the molecule. The approach also provides a practical means of obtaining microcanonical rates at considerable savings of computer time compared to trajectory simulations. The method is applied to the unimolecular dissociation of RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), and its accuracy is demonstrated by comparison with the results from trajectory and Monte Carlo variational transition state theory calculations. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Oklahoma State Univ, Dept Chem, Stillwater, OK 74078 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 18 TC 3 Z9 3 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 DEC 9 PY 1999 VL 103 IS 49 BP 10308 EP 10311 DI 10.1021/jp991592e PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 266UM UT WOS:000084318700035 ER PT J AU Xu, QH Scholes, GD Yang, M Fleming, GR AF Xu, QH Scholes, GD Yang, M Fleming, GR TI Probing solvation and reaction coordinates of ultrafast photoinduced electron-transfer reactions using nonlinear spectroscopies: Rhodamine 6G in electron-donating solvents SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID CHARGE-TRANSFER COMPLEX; GEMINATE ION-PAIR; POLAR-SOLVENTS; TRANSFER DYNAMICS; FLASH-PHOTOLYSIS; LIQUID ANILINES; PHOTON-ECHO; N,N-DIMETHYLANILINE; DYES; RECOMBINATION AB The reaction kinetics as well as the solvation dynamics of the photoinduced electron-transfer (ET) reaction from the electron-donating solvents dimethylaniline (DMA) and diethylaniline (DEA) to rhodamine 6G (R6G) are elucidated using complementary information from transient grating (TG) and three-pulse photon echo peak shift (3PEPS) measurements. The data are contrasted with those obtained from TG and 3PEPS studies in the "unreactive" solvents ethanol and dimethyl sulfoxide. New methods are employed to model these data using nonlinear response functions expressed in terms of both solvation dynamics and reaction kinetics. A three-level model, including a component in the response function to account for excited-state absorption, is used to model the 3PEPS and TG data. It is also demonstrated that 3PEPS retrieves information concerning the reaction coordinate as well as solvation information. We conclude that for R6G/DMA, rapid photoinduced ET occurs on a time scale of tau(a) similar to 85 fs and for the R6G/DEA system tau(a) similar to 160 fs, An excited-state absorption contribution to the signals that we associate with back-electron transfer was observed with time constants tau(b) = 4.0 ps for R6G/DMA (15% contribution) and tau(b) = 6.9 ps for R6G/DEA (20% contribution). Subsequently, the cooling and relaxation (i.e. ground-state recovery) occurs on a time scale of tau(c) = 19 ps (R6G/DMA) and tau(c) = 50 ps (R6G/DEA). We attribute the tau(c) to solvent-limited reequilibration on the ground-state free energy curve. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA. RP Fleming, GR (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Chem, Berkeley, CA 94720 USA. RI Xu, Qing-Hua/B-1478-2013; OI Xu, Qing-Hua/0000-0002-4153-0767; Yang, Mino/0000-0001-9504-0280 NR 74 TC 83 Z9 85 U1 0 U2 29 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 DEC 9 PY 1999 VL 103 IS 49 BP 10348 EP 10358 DI 10.1021/jp991852s PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 266UM UT WOS:000084318700040 ER PT J AU Neyer, DW Heck, AJR Chandler, DW Teule, JM Janssen, MHM AF Neyer, DW Heck, AJR Chandler, DW Teule, JM Janssen, MHM TI Speed-dependent alignment and angular distributions of O(D-1(2))from the ultraviolet photodissociation of N2O SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID ENHANCED MULTIPHOTON IONIZATION; STATE-RESOLVED STEREODYNAMICS; STRATOSPHERIC NITROUS-OXIDE; DYNAMICS; SPECTRA; DISSOCIATION; EXCITATION; OXYGEN; NO2 AB Photofragment ion imaging has been used to study the O(D-1(2)) atoms produced in the ultraviolet (similar to 200 nm) photodissociation of nitrous oxide (N2O) in a molecular beam. The images of O(D-1(2)) reveal a speed-dependent angular distribution resulting from both variation in the spatial anisotropy of the recoil and alignment of the electronic angular momentum of the O(D-1(2)) fragment. The orbital alignment effects are revealed by a change in the images when different transitions of the O atom are employed in the resonance enhanced multiphoton ionization (REMPI) process. By correlating the O atom anisotropies with previously measured values for the complementary N-2 fragments and comparing images collected on two different REMPI transitions, we calculate the relative branching ratios and anisotropies for the three different \m\ values (defined along the product recoil axis) of the electronic angular momentum of the O(D-1(2)) fragment. While m = 0 fragments have the highest probability for most O atom speeds, there is a significant change in the alignment and angular distributions for the slower O atoms. We use a simplified dynamical model supported by previous theoretical structure calculations to explain the measured trends and to estimate the relative branching in the excitation to two N2O electronic states. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. Univ Utrecht, Dept Chem, NL-3584 CH Utrecht, Netherlands. Univ Utrecht, Dept Pharm, NL-3584 CH Utrecht, Netherlands. Vrije Univ Amsterdam, Ctr Laser, Amsterdam, Netherlands. Vrije Univ Amsterdam, Dept Chem, Amsterdam, Netherlands. RP Chandler, DW (reprint author), Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. RI Heck, Albert/D-7098-2011 OI Heck, Albert/0000-0002-2405-4404 NR 38 TC 42 Z9 43 U1 0 U2 15 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 DEC 9 PY 1999 VL 103 IS 49 BP 10388 EP 10397 DI 10.1021/jp9922918 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 266UM UT WOS:000084318700045 ER PT J AU Snee, PT Yang, H Kotz, KT Payne, CK Harris, CB AF Snee, PT Yang, H Kotz, KT Payne, CK Harris, CB TI Ultrafast infrared studies of the reaction mechanism of silicon-hydrogen bond activation by eta(5)-CpV(CO)(4) SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID TRANSITION-METAL ATOMS; MOLECULAR-ORBITAL METHODS; EFFECTIVE CORE POTENTIALS; AB-INITIO CALCULATIONS; GAS-PHASE; TUNGSTEN PENTACARBONYL; BASIS-SET; CA 12-K; COMPLEXES; PHOTOCHEMISTRY AB The photochemical Si-H bond activation reaction by the group VB, d(4) organometallic compound eta(5)-CpV(CO)(4) (Cp = C5H5) has been studied in neat triethylsilane under ambient conditions, The spectral evolutions of the metal-bended CO stretching bands were monitored from 300 fs to 800 ps following UV photolysis using femtosecond pump-probe spectroscopic methods. The reactive intermediates observed on the ultrafast time scale were also studied using density functional theory as well as ab initio quantum chemical modeling. It was found that photolysis of vanadium tetracarbonyl resulted in the formation of tricarbonyls in either the singlet or triplet electronic state following CO loss. The subsequent reaction was partitioned into two pathways by the initial solvation of the tricarbonyls through the Si-H bond or an ethyl group of the solvent molecule. Knowledge of the elementary reaction steps including changes in molecular morphology and electronic multiplicity allowed a comprehensive description of the chemical reactivity. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Ernest Orlando Lawrence Berkeley Natl Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Harris, CB (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Payne, Christine/E-5954-2010; OI Yang, Haw/0000-0003-0268-6352 NR 57 TC 23 Z9 23 U1 0 U2 11 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 DEC 9 PY 1999 VL 103 IS 49 BP 10426 EP 10432 DI 10.1021/jp991964j PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 266UM UT WOS:000084318700049 ER PT J AU Schenter, GK Lu, HP Xie, XS AF Schenter, GK Lu, HP Xie, XS TI Statistical analyses and theoretical models of single-molecule enzymatic dynamics SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID SPECTRAL DIFFUSION; IMPURITY MOLECULES; CHEMICAL-REACTIONS; PROTEINS; FLUORESCENCE; SPECTROSCOPY AB Real-time observation of enzymatic turnovers-of single molecules has revealed non-Markovian dynamical behavior. Although chemical kinetics (such as the Michaelis-Menten mechanism) are sufficient to describe the average behavior of an ensemble of molecules, statistical analysis of the single-molecule fluorescence time trace reveals fluctuations in the rate of the activation step. These fluctuations are attributed to slow fluctuations of protein conformations. In this paper, we discuss models of the dynamical disorder behavior and relate them to observables of single molecule experiments. Simulations based on a discrete multistate model and a diffusive model are compared with experiment data. The role of various correlation functions, including higher order time correlation functions, in the interpretation of the underlying dynamics is discussed. C1 Pacific NW Lab, William R Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. Harvard Univ, Dept Chem & Biol Chem, Cambridge, MA 02138 USA. RP Schenter, GK (reprint author), Pacific NW Lab, William R Wiley Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. RI Schenter, Gregory/I-7655-2014 OI Schenter, Gregory/0000-0001-5444-5484 NR 46 TC 116 Z9 119 U1 0 U2 19 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 DEC 9 PY 1999 VL 103 IS 49 BP 10477 EP 10488 DI 10.1021/jp992324j PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 266UM UT WOS:000084318700056 ER PT J AU Bardeen, CJ Rosenthal, SJ Shank, CV AF Bardeen, CJ Rosenthal, SJ Shank, CV TI Ultrafast solvation processes in polar liquids probed with large organic molecules SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID TIME-DEPENDENT FLUORESCENCE; STIMULATED PHOTON-ECHO; STOKES SHIFT; ABSORPTION-SPECTROSCOPY; PEAK SHIFT; DYNAMICS; SOLVENT; SOLUTE; BACTERIORHODOPSIN; SIMULATION AB Several optical techniques are used to characterize the ultrafast solvation dynamics of two structurally different molecules, LD690 and LDS750. Linear absorption, fluorescence, resonance Raman, and time-resolved four-wave mixing experiments have been performed on both molecules in a variety of solvents. The combination of different experiments is necessary to characterize the femtosecond dynamics. We find that both molecules exhibit very fast dephasing, due to sub-100 fs decays of the solvation correlation function M(t). The LD690 data is analyzed in depth, using a multimode oscillator model to treat both intramolecular vibrations and the solvent coordinates. The dynamics are solvent-dependent, but this dependence cannot be explained in a straightforward manner using quantities such as inertial solvent rotational motion or a simple dielectric continuum response. Various aspects of the spectroscopy, both linear and nonlinear, provide clues that the dynamics are influenced by molecular-level interactions that are not taken into account by theories that only consider bulk solvent properties. C1 Univ Calif Berkeley, Dept Biochem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Shank, CV (reprint author), Univ Calif Berkeley, Dept Biochem, Berkeley, CA 94720 USA. NR 52 TC 33 Z9 33 U1 4 U2 14 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 DEC 9 PY 1999 VL 103 IS 49 BP 10506 EP 10516 DI 10.1021/jp991974k PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 266UM UT WOS:000084318700058 ER PT J AU Berthold, T Bechtold, M Heinen, U Link, G Poluektov, O Utschig, L Tang, J Thurnauer, MC Kothe, G AF Berthold, T Bechtold, M Heinen, U Link, G Poluektov, O Utschig, L Tang, J Thurnauer, MC Kothe, G TI Magnetic-field-induced orientation of photosynthetic reaction centers as revealed by time-resolved W-band EPR of spin-correlated radical pairs SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Letter ID BACTERIAL REACTION CENTERS; ELECTRON-PARAMAGNETIC-RESONANCE; I SINGLE-CRYSTALS; PHOTOSYSTEM-I; STATE P(700)(CENTER-DOT+)A(1)(CENTER-DOT-); PULSED EPR; SPECTROSCOPY; RESOLUTION; SPECTRA; SYSTEMS AB The spin-polarized W-band EPR spectra of the secondary radical pair in plant photosystem I indicate a magnetic-field-induced orientation of the photosynthetic reaction centers in the field of the EPR spectrometer. This orientation arises due to the anisotropy of the diamagnetic susceptibility of the reaction center protein. Analysis of the angular-dependent EPR spectra on the basis of the spin-correlated radical pair concept provides new information on the cofactor arrangement in plant photosystem I. C1 Univ Freiburg, Dept Chem Phys, D-79104 Freiburg, Germany. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Kothe, G (reprint author), Univ Freiburg, Dept Chem Phys, Albertstr 21, D-79104 Freiburg, Germany. RI Tang, Jau/D-8382-2012 OI Tang, Jau/0000-0003-2078-1513 NR 27 TC 21 Z9 23 U1 2 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 DEC 9 PY 1999 VL 103 IS 49 BP 10733 EP 10736 DI 10.1021/jp992011o PG 4 WC Chemistry, Physical SC Chemistry GA 266UL UT WOS:000084318600002 ER PT J AU Aggarwal, MM Agnihotri, A Ahammed, Z Angelis, ALS Antonenko, V Arefiev, V Astakhov, V Avdeitchikov, V Awes, TC Baba, PVKS Badyal, SK Baldine, A Barabach, L Barlag, C Bathe, S Batiounia, B Bernier, T Bhalla, KB Bhatia, VS Blume, C Bock, R Bohne, EM Borocz, Z Bucher, D Buijs, A Busching, H Carlen, L Chalyshev, V Chattopadhyay, S Cherbatchev, R Chujo, T Claussen, A Das, AC Decowski, MP Delagrange, H Djordjadze, V Donni, P Doubovik, I Dutt, S Majumdar, MRD El Chenawi, K Eliseev, S Enosawa, K Foka, P Fokin, S Frolov, V Ganti, MS Garpman, S Gavrishchuk, O Geurts, FJM Ghosh, TK Glasow, R Gupta, SK Guskov, B Gustafsson, HA Gutbrod, HH Higuchi, R Hrivnacova, I Ippolitov, M Kalechofsky, H Kamermans, R Kampert, KH Karadjev, K Karpio, K Kato, S Kees, S Kolb, BW Kosarev, I Koutcheryaev, I Krumpel, T Kugler, A Kulinich, P Kurata, M Kurita, K Kuzmin, N Langbein, I Lebedev, A Lee, YY Lohner, H Luquin, L Mahapatra, DP Manko, V Martin, M Martinez, G Maximov, A Mehdiyev, R Mgebrichvili, G Miake, Y Mikhalev, D Mir, MF Mishra, GC Miyamoto, Y Morrison, D Mohanty, B Mukhopadhyay, DS Myalkovski, V Naef, H Nandi, BK Nayak, SK Nayak, TK Neumaier, S Nianine, A Nikitine, V Nikolaev, S Nilsson, P Nishimura, S Nomokonov, P Nystrand, J Obenshain, FE Oskarsson, A Otterlund, I Pachr, M Parfenov, A Pavliouk, S Peitzmann, T Petracek, V Plasil, F Pinganaud, W Purschke, ML Raeven, B Rak, J Raniwala, R Raniwala, S Ramamurthy, VS Rao, NK Retiere, F Reygers, K Roland, G Rosselet, L Roufanov, I Roy, C Rubio, JM Sako, H Sambyal, SS Santo, R Sato, S Schlagheck, H Schmidt, HR Schutz, Y Shabratova, G Shah, TH Sibiriak, I Siemiarczuk, T Silvermyr, D Sinha, BC Salvine, N Soderstrom, K Solomey, N Sorensen, SP Stankus, P Stefanek, G Steinberg, P Stenlund, E Stuken, D Sumbera, M Svensson, T Trivedi, MD Tsvetkov, A Tykarski, L Urbahn, J vander Pijll, EC von Eijndhoven, N von Nieuwenhuizen, GJ Vinogradov, A Viyogi, YP Vodopianov, A Voros, S Wyslouch, B Yagi, K Yokota, Y AF Aggarwal, MM Agnihotri, A Ahammed, Z Angelis, ALS Antonenko, V Arefiev, V Astakhov, V Avdeitchikov, V Awes, TC Baba, PVKS Badyal, SK Baldine, A Barabach, L Barlag, C Bathe, S Batiounia, B Bernier, T Bhalla, KB Bhatia, VS Blume, C Bock, R Bohne, EM Borocz, Z Bucher, D Buijs, A Busching, H Carlen, L Chalyshev, V Chattopadhyay, S Cherbatchev, R Chujo, T Claussen, A Das, AC Decowski, MP Delagrange, H Djordjadze, V Donni, P Doubovik, I Dutt, S Majumdar, MRD El Chenawi, K Eliseev, S Enosawa, K Foka, P Fokin, S Frolov, V Ganti, MS Garpman, S Gavrishchuk, O Geurts, FJM Ghosh, TK Glasow, R Gupta, SK Guskov, B Gustafsson, HA Gutbrod, HH Higuchi, R Hrivnacova, I Ippolitov, M Kalechofsky, H Kamermans, R Kampert, KH Karadjev, K Karpio, K Kato, S Kees, S Kolb, BW Kosarev, I Koutcheryaev, I Krumpel, T Kugler, A Kulinich, P Kurata, M Kurita, K Kuzmin, N Langbein, I Lebedev, A Lee, YY Lohner, H Luquin, L Mahapatra, DP Manko, V Martin, M Martinez, G Maximov, A Mehdiyev, R Mgebrichvili, G Miake, Y Mikhalev, D Mir, MF Mishra, GC Miyamoto, Y Morrison, D Mohanty, B Mukhopadhyay, DS Myalkovski, V Naef, H Nandi, BK Nayak, SK Nayak, TK Neumaier, S Nianine, A Nikitine, V Nikolaev, S Nilsson, P Nishimura, S Nomokonov, P Nystrand, J Obenshain, FE Oskarsson, A Otterlund, I Pachr, M Parfenov, A Pavliouk, S Peitzmann, T Petracek, V Plasil, F Pinganaud, W Purschke, ML Raeven, B Rak, J Raniwala, R Raniwala, S Ramamurthy, VS Rao, NK Retiere, F Reygers, K Roland, G Rosselet, L Roufanov, I Roy, C Rubio, JM Sako, H Sambyal, SS Santo, R Sato, S Schlagheck, H Schmidt, HR Schutz, Y Shabratova, G Shah, TH Sibiriak, I Siemiarczuk, T Silvermyr, D Sinha, BC Salvine, N Soderstrom, K Solomey, N Sorensen, SP Stankus, P Stefanek, G Steinberg, P Stenlund, E Stuken, D Sumbera, M Svensson, T Trivedi, MD Tsvetkov, A Tykarski, L Urbahn, J vander Pijll, EC von Eijndhoven, N von Nieuwenhuizen, GJ Vinogradov, A Viyogi, YP Vodopianov, A Voros, S Wyslouch, B Yagi, K Yokota, Y CA WA98 Collaboration TI Elliptic emission of K+ and pi(+) in 158 A center dot GeV Pb + Pb collisions SO PHYSICS LETTERS B LA English DT Article ID HEAVY-ION COLLISIONS; RELATIVISTIC NUCLEAR COLLISIONS; OF-PLANE EMISSION; PB+PB COLLISIONS; AU+AU COLLISIONS; COLLECTIVE FLOW; ANISOTROPIC FLOW; KAON FLOW; MATTER; ENERGY AB An event-by-event analysis of the azimuthal angular correlation with respect to the reaction plane has been carried out for K+ and pi(+) emission near mid-rapidity in 158 A . GeV Pb + Pb collisions. In semi-central collisions, K+ mesons are found to be preferentially emitted out of the reaction plane, while pi(+) mesons are emitted in the reaction plane. The results suggest that the kaon emission is influenced by in-medium potential effects in addition to collective flow effects. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Panjab Univ, Chandigarh 160014, India. Univ Rajasthan, Jaipur 302004, Rajasthan, India. Ctr Variable Energy Cyclotron, Calcutta 700064, W Bengal, India. Univ Geneva, CH-1211 Geneva 4, Switzerland. RRC Kurchatov Inst, RU-123182 Moscow, Russia. Joint Nucl Res Inst, RU-141980 Dubna, Russia. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Jammu, Jammu 180001, India. Univ Munster, D-48149 Munster, Germany. Ecole Mines, SUBATECH, Nantes, France. Gesell Schwerionenforsch GmbH, D-64220 Darmstadt, Germany. Univ Utrecht, NIKHEF, NL-3508 TA Utrecht, Netherlands. Univ Lund, SE-22100 Lund, Sweden. Univ Tsukuba, Tsukuba, Ibaraki 305, Japan. Inst Phys Nucl, CZ-25068 Rez, Czech Republic. Univ Groningen, KVI, NL-9747 AA Groningen, Netherlands. Inst Nucl Studies, PL-00681 Warsaw, Poland. MIT, Cambridge, MA 02139 USA. Inst Phys, Bhubaneswar 751005, Orissa, India. Univ Tennessee, Knoxville, TN 37966 USA. RP Aggarwal, MM (reprint author), Panjab Univ, Chandigarh 160014, India. RI Decowski, Patrick/A-4341-2011; Peitzmann, Thomas/K-2206-2012; Mehdiyev, Rashid/H-6299-2013; Lohner, Herbert/B-2397-2014; Sumbera, Michal/O-7497-2014; OI Peitzmann, Thomas/0000-0002-7116-899X; Lohner, Herbert/0000-0002-7441-739X; Sumbera, Michal/0000-0002-0639-7323; Mohanty, Bedangadas/0000-0001-9610-2914 NR 44 TC 14 Z9 14 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 DEC 9 PY 1999 VL 469 IS 1-4 BP 30 EP 36 DI 10.1016/S0370-2693(99)01289-7 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 265BZ UT WOS:000084222400006 ER PT J AU Abele, A Adomeit, J Amsler, C Anisovich, AV Baker, CA Barnett, BM Batty, CJ Berdoz, A Bischoff, S Blum, P Braune, K Bugg, DV Case, T Cramer, O Crede, V Crowe, KM Degener, T Doser, M Dunnweber, W Ehmanns, A Engelhardt, D Faessler, MA Giarritta, P Haddock, RP Heinsius, FH Heinzelmann, M Herbstrith, A Herz, M Hessey, NP Hidas, P Hodd, C Holtzhaussen, C Jamnik, D Kalinowsky, H Kammel, P Kisiel, J Klempt, E Koch, H Kunze, M Kurilla, U Lakata, M Landua, R Matthay, H McCrady, R Meier, J Meyer, CA Ouared, R Peters, K Pick, B Ratajczak, M Regenfus, C Roethel, W Spanier, S Stock, H Strassburger, C Strohbusch, U Suffert, M Suh, JS Thoma, U Tischhauser, M Uman, I Volcker, C Wallis-Plachner, S Walther, D Wiedner, U Wittmack, K Zou, BS AF Abele, A Adomeit, J Amsler, C Anisovich, AV Baker, CA Barnett, BM Batty, CJ Berdoz, A Bischoff, S Blum, P Braune, K Bugg, DV Case, T Cramer, O Crede, V Crowe, KM Degener, T Doser, M Dunnweber, W Ehmanns, A Engelhardt, D Faessler, MA Giarritta, P Haddock, RP Heinsius, FH Heinzelmann, M Herbstrith, A Herz, M Hessey, NP Hidas, P Hodd, C Holtzhaussen, C Jamnik, D Kalinowsky, H Kammel, P Kisiel, J Klempt, E Koch, H Kunze, M Kurilla, U Lakata, M Landua, R Matthay, H McCrady, R Meier, J Meyer, CA Ouared, R Peters, K Pick, B Ratajczak, M Regenfus, C Roethel, W Spanier, S Stock, H Strassburger, C Strohbusch, U Suffert, M Suh, JS Thoma, U Tischhauser, M Uman, I Volcker, C Wallis-Plachner, S Walther, D Wiedner, U Wittmack, K Zou, BS TI The rho-mass, width and line shape in (p)over-barp annihilation at rest into pi(+)pi(-)pi(0) SO PHYSICS LETTERS B LA English DT Article AB A high-statistics data sample on (p) over bar p --> pi(+)pi(-)pi(0) is studied to deduce the mass, width, and Line shape of charged and neutral rho mesons. We find that the line shape is well described by a relativistic Breit-Wigner function. We find mass degeneracy of the rho(+/-) and rho(0) masses when mixing with the omega in its pi(+)pi(-) decay mode is taken into account. A fit with one mass and width for the three rho charge states yields m(rho) = (763.0 +/- 1.3) MeV and Gamma(rho) = (149.5 +/- 1.3) MeV. The mass difference between charged and neutral rho's is determined to be (1.6 +/- 0.6 +/- 1.7) MeV. A possible influence on the rho mass due to the isobar approximation is discussed. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Karlsruhe, D-76021 Karlsruhe, Germany. Univ Calif Berkeley, LBNL, Berkeley, CA 94720 USA. Univ Bochum, D-44780 Bochum, Germany. Univ Bonn, D-53115 Bonn, Germany. Hungarian Acad Sci, H-1525 Budapest, Hungary. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. CERN, CH-1211 Geneva 4, Switzerland. Univ Hamburg, D-22761 Hamburg, Germany. Univ London Queen Mary & Westfield Coll, London E1 4NS, England. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. Univ Munich, D-80333 Munich, Germany. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Ctr Rech Nucl, F-67037 Strasbourg, France. Univ Zurich, CH-8057 Zurich, Switzerland. RP Abele, A (reprint author), Univ Karlsruhe, D-76021 Karlsruhe, Germany. RI Peters, Klaus/C-2728-2008; Meyer, Curtis/L-3488-2014 OI Peters, Klaus/0000-0001-7133-0662; Meyer, Curtis/0000-0001-7599-3973 NR 11 TC 9 Z9 9 U1 0 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 DEC 9 PY 1999 VL 469 IS 1-4 BP 270 EP 275 DI 10.1016/S0370-2693(99)01284-8 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 265BZ UT WOS:000084222400041 ER PT J AU Abele, A Adomeit, J Amsler, C Baker, CA Barnett, BM Batty, CJ Benayoun, M Berdoz, A Bischoff, S Blum, P Braune, K Bugg, DV Case, T Cramer, O Crowe, KM Degener, T Djaoshvili, N Doser, M Dunnweber, W Engelhardt, D Faessler, MA Giarritta, P Haddock, RP Heinsius, FH Heinzelmann, M Herbstrith, A Herz, M Hessey, NP Hidas, P Hodd, C Holtzhaussen, C Jamnik, D Kalinowsky, H Kammel, P Kisiel, J Klempt, E Koch, H Kunze, M Kurilla, U Lakata, M Landua, R Matthay, H McCrady, R Meier, J Meyer, CA Montanet, L Ouared, R Peters, K Pick, B Ratajczak, M Regenfus, C Roethel, W Seibert, R Spanier, S Stock, H Strassburger, C Strohbusch, U Suffert, M Suh, JS Thoma, U Tischhauser, M Uman, I Volcker, C Wallis-Plachner, S Walther, D Wiedner, U Wittmack, K Zou, BS Zupancic, C AF Abele, A Adomeit, J Amsler, C Baker, CA Barnett, BM Batty, CJ Benayoun, M Berdoz, A Bischoff, S Blum, P Braune, K Bugg, DV Case, T Cramer, O Crowe, KM Degener, T Djaoshvili, N Doser, M Dunnweber, W Engelhardt, D Faessler, MA Giarritta, P Haddock, RP Heinsius, FH Heinzelmann, M Herbstrith, A Herz, M Hessey, NP Hidas, P Hodd, C Holtzhaussen, C Jamnik, D Kalinowsky, H Kammel, P Kisiel, J Klempt, E Koch, H Kunze, M Kurilla, U Lakata, M Landua, R Matthay, H McCrady, R Meier, J Meyer, CA Montanet, L Ouared, R Peters, K Pick, B Ratajczak, M Regenfus, C Roethel, W Seibert, R Spanier, S Stock, H Strassburger, C Strohbusch, U Suffert, M Suh, JS Thoma, U Tischhauser, M Uman, I Volcker, C Wallis-Plachner, S Walther, D Wiedner, U Wittmack, K Zou, BS Zupancic, C TI Observation of Pontecorvo reactions with open strangeness: (p)over-bard -> Lambda K-0 and (p)over-bard -> Sigma K-0(0) SO PHYSICS LETTERS B LA English DT Article ID ANTIPROTON ANNIHILATION; NUCLEI; SPECTROMETER; DEUTERIUM; LEAR AB We report the first observation of antiproton annihilation on the deuteron into two-body channels with open strangeness. These reactions are of the Pontecorvo type, designating annihilations kinematically not possible on a free nucleon. With antiprotons stopped in a liquid deuterium target, a K-S(0) and Lambda enriched sample of events, corresponding to about 10(9) annihilations, was recorded with the Crystal Barrel experiment, using a Silicon microstrip detector for triggering on secondary decays. The final states Lambda K-S(0) and Sigma(0)K(S)(0), with Sigma(0) --> Lambda gamma, Lambda --> p pi(-), K-S(0) --> pi(+)pi(-), and the equivalent final states Lambda K-L(0) and Sigma(0)K(L)(0), with noninteracting K-L(0), were identified. The (p) over bar d branching fraction into Lambda K-0 and Sigma(0)K(0) are (2.35 +/- 0.45) X 10(-6) and (2.15 +/- 0.45) X 10(-6), respectively. This similarity disagrees strongly with two-step model predictions and supports the statistical (fireball) model. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, LBNL, Berkeley, CA 94720 USA. Univ Bochum, D-44780 Bochum, Germany. Univ Bonn, D-53115 Bonn, Germany. Hungarian Acad Sci, H-1525 Budapest, Hungary. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. CERN, CH-1211 Geneva 4, Switzerland. Univ Hamburg, D-22761 Hamburg, Germany. Univ Karlsruhe, D-76021 Karlsruhe, Germany. Univ London Queen Mary & Westfield Coll, London E1 4NS, England. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. Univ Munich, D-80333 Munich, Germany. LPNHE Paris 6, F-75252 Paris, France. LPNHE Paris 7, F-75252 Paris, France. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Ctr Rech Nucl, F-67037 Strasbourg, France. Univ Zurich, CH-8057 Zurich, Switzerland. RP Abele, A (reprint author), Univ Calif Berkeley, LBNL, Berkeley, CA 94720 USA. RI Peters, Klaus/C-2728-2008; Meyer, Curtis/L-3488-2014 OI Peters, Klaus/0000-0001-7133-0662; Meyer, Curtis/0000-0001-7599-3973 NR 23 TC 9 Z9 9 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 DEC 9 PY 1999 VL 469 IS 1-4 BP 276 EP 286 DI 10.1016/S0370-2693(99)01225-3 PG 11 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 265BZ UT WOS:000084222400042 ER PT J AU Lee, HS McCoy, AB Harding, LB Carter, CC Miller, TA AF Lee, HS McCoy, AB Harding, LB Carter, CC Miller, TA TI An empirical potential energy surface for the Ne-OH/D complexes SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID RESOLUTION ELECTRONIC SPECTROSCOPY; CORRELATED MOLECULAR CALCULATIONS; GAUSSIAN-BASIS SETS; VIBRATIONAL DEPENDENCE; VANDERWAALS COMPLEXES; DYNAMICS; SPECTRA; NE.OH AB An empirical potential energy surface has been developed for the Ne-OH/D complexes from the experimentally observed vibrational and rotational energy levels with the results of ab initio calculations being used to provide initial estimates of the values of the parameters in the empirical potential. To determine the final surface a reassignment of the (A) over tilde (2)Sigma(+)-X (2)Pi bend-stretch combination bands, to fundamentals of the bend, was made, and the experimental data for both the Ne-OH and Ne-OD complexes were fit simultaneously due to the small number of available values. The vibrational energies and rotational constants resulting from the fit surface are within 0.2 and 0.0013 cm(-1), respectively, of the experimental values. The details of the potential energy surface are discussed in relationship to those of other inert gas complexes containing OH and SH, as well as HCl and HF. (C) 1999 American Institute of Physics. [S0021-9606(99)01646-3]. C1 Ohio State Univ, Dept Chem, Columbus, OH 43210 USA. Argonne Natl Lab, Dept Chem, Argonne, IL 60439 USA. RP Ohio State Univ, Dept Chem, 120 W 18th Ave, Columbus, OH 43210 USA. RI Miller, Terry/F-6607-2014 OI Miller, Terry/0000-0003-0731-8006 NR 33 TC 10 Z9 10 U1 0 U2 1 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 DEC 8 PY 1999 VL 111 IS 22 BP 10053 EP 10060 DI 10.1063/1.480391 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 258RK UT WOS:000083852700017 ER PT J AU Yoo, CS Cynn, H AF Yoo, CS Cynn, H TI Equation of state, phase transition, decomposition of beta-HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) at high pressures SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article AB Pressure-volume relations and vibrational Raman spectra of unreacted HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) have been obtained in both quasihydrostatic conditions to 45 GPa and nonhydrostatic conditions to 10 GPa by using diamond-anvil cell, angle-resolved synchrotron x-ray diffraction, and micro-Raman spectroscopy. The results show that the high-pressure behavior of HMX strongly depends on the stress conditions. HMX is more compressible in hydrostatic conditions (B-0=12.4 GPa and B-'=10.4) than in nonhydrostatic conditions (B-0=14.4 GPa, B-'=13.3). This discrepancy in HMX compressibility can be explained in terms of chemical reactions occurring in nonhydrostatic conditions. The static isotherm is in good agreement with the shock Hugoniot, suggesting little temperature effect on the pressure-volume relation. The hydrostatic data suggest that beta(monoclinic)-HMX undergoes two phase transitions: (i) a conformational transition at 12 GPa with no apparent abrupt volume change and (ii) a discontinuous one at 27 GPa with a 4% volume change. At 40 GPa, the b and c axes become nearly identical with the c/a ratio 1.62 and beta=123 degrees, approaching a nearly close-packed structure. (C) 1999 American Institute of Physics. [S0021-9606(99)51025-8]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Yoo, CS (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NR 21 TC 105 Z9 111 U1 2 U2 23 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 DEC 8 PY 1999 VL 111 IS 22 BP 10229 EP 10235 DI 10.1063/1.480341 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 258RK UT WOS:000083852700037 ER PT J AU Omotowa, BA Keefer, KD Kirchmeier, RL Shreeve, JM AF Omotowa, BA Keefer, KD Kirchmeier, RL Shreeve, JM TI Preparation and characterization of nonpolar fluorinated carbosilane dendrimers by APcI mass spectrometry and small-angle X-ray scattering SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID END-GROUPS; MACROMOLECULES; NANOCLUSTERS; MOLECULES; BONDS AB The following highly fluorinated nonpolar dendrimers were obtained in high yields from multiple hydrosilylation reactions between core hydride terminated carbosilane dendrimers and ally1-1,1-dihydrofluoroethyl ether or ally1-1,1-dihydroheptadecafluorononyl ether through divergent synthetic routes: Si[CH2CH2SiMe2(CH2CH2CH2OCH2CF3)](4) (7),Si{CH2CH2SiMe[CH2CH2SiMe(CH2CH2CH2OCH2CF3)(2)](2)}(4) (8), Si[CH2CH2Si(CH2CH2CH2OCH2C8F17)(3)]4 (9), Si[CH2CH2SiMe2(CH2CH2CH2OCH2C8F17)](4) (10), and Si{CH2CH2Si[CH2CH2Si(CH2CH2CH2OCH2C8F17)(3)](3)}(4) (11) These compounds were characterized by elemental and spectroscopic analyses. Valuable mass spectral data were obtained by using atmospheric pressure chemical ionization (APcI). The fluorinated dendrimer molecule and the nonfluorinated core scatter X-ray light differently and present unique slopes on the Guinier Plot of data from small-angle X-ray light scattering (SAXS) in hexafluorobenzene. Glass transition temperatures (T-g) and thermogravimetric analyses (TGA) of the dendrimers were determined. C1 Univ Idaho, Dept Chem, Moscow, ID 83844 USA. Pacific NW Lab, William R Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Shreeve, JM (reprint author), Univ Idaho, Dept Chem, Moscow, ID 83844 USA. NR 32 TC 30 Z9 31 U1 3 U2 7 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 DEC 8 PY 1999 VL 121 IS 48 BP 11130 EP 11138 DI 10.1021/ja992794r PG 9 WC Chemistry, Multidisciplinary SC Chemistry GA 263ZN UT WOS:000084155300014 ER PT J AU Modine, NA Kaxiras, E AF Modine, NA Kaxiras, E TI Theory of the (3 x 2) reconstruction of the GaAs(001) surface SO MATERIALS SCIENCE AND ENGINEERING B-SOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY LA English DT Article; Proceedings Paper CT 1st Lawrence Symposium on Critical Issues in Epitaxy CY JAN 06-09, 1999 CL UNIV ARIZONA, CTR SOLID STATE SCI, MESA, ARIZONA HO UNIV ARIZONA, CTR SOLID STATE SCI DE density functional theory; (3 x 2) reconstruction; GaAs(001) surface ID SCANNING-TUNNELING-MICROSCOPY; SPACE ELECTRONIC-STRUCTURE; POLAR SEMICONDUCTOR SURFACES; ADAPTIVE-COORDINATE; GAAS(100) SURFACES; ATOMIC-STRUCTURE; MODEL; ENERGIES; 2X2 AB We discuss an ab initio density functional theory investigation of a (3 x 2) reconstruction of the Ga-rich GaAs(001) surface. Recent experiments identified this new reconstruction as a stable surface of epitaxially grown GaAs doped with indium or carbon (L. Li, et al., Appl. Phys. A 66 (1998) S501; L. Li, et al., Ultramicroscopy 73 (1998) 229). Using our recently developed real-space pseudopotential density functional code, we investigate this (3 x 2) reconstruction and evaluate stabilization mechanisms for the model proposed by the experimentalists, which does not satisfy the electron counting rule. In order to study the effect of In substitution, we consider the dependence of the surface energies of competing reconstructions on surface strain and relative chemical potentials. The effects of carbon substitution are modeled using a charged (3 x 2) reconstruction. These studies support and clarify the proposed structure and stabilization mechanisms. We provide a simple physical explanation for the behavior of the surface energy of the (3 x 2) reconstruction. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Harvard Univ, Dept Phys, Cambridge, MA 02138 USA. RP Modine, NA (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 26 TC 3 Z9 3 U1 0 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 DEC 8 PY 1999 VL 67 IS 1-2 BP 1 EP 6 DI 10.1016/S0921-5107(99)00202-0 PG 6 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 266PY UT WOS:000084309400002 ER PT J AU Newman, J Peat, TS Richard, R Kan, L Swanson, PE Affholter, JA Holmes, IH Schindler, JF Unkefer, CJ Terwilliger, TC AF Newman, J Peat, TS Richard, R Kan, L Swanson, PE Affholter, JA Holmes, IH Schindler, JF Unkefer, CJ Terwilliger, TC TI Haloalkane dehalogenases: Structure of a Rhodococcus enzyme SO BIOCHEMISTRY LA English DT Article ID XANTHOBACTER-AUTOTROPHICUS GJ10; HISTIDINE-ASPARTATE COUPLE; HALIDE-BINDING-SITE; X-RAY; S(N)2 DISPLACEMENT; TRANSITION-STATE; ACTIVE-SITE; 1,2-DICHLOROETHANE; DEGRADATION; KINETICS AB The hydrolytic haloalkane dehalogenases are promising bioremediation and biocatalytic agents. Two:general classes of dehalogenases have been reported from Xanthobacter and Rhodococcus, While these enzymes share 30% amino acid sequence identity, they have significantly different substrate specificities and halide-binding properties. We report the 1.5 Angstrom resolution crystal structure of the Rhodococcus dehalogenase at pH 5.5, pH 7.0, and pH 5.5 in the presence of NaI, The Rhodococcus and Xanthobacter enzymes have significant structural homology in the alpha/beta hydrolase core, but differ considerably in the cap domain. Consistent with its broad specificity for primary, secondary, and cyclic haloalkanes, the Rhodococcus enzyme has a substantially larger active site cavity. Significantly, the Rhodococcus dehalogenase has a different catalytic triad topology than the Xanthobacter enzyme. In the Xanthobacter dehalogenase, the third carboxylate functionality in the triad is provided by D260, which is positioned on the loop between beta 7 and the penultimate helix. The carboxylate functionality in the Rhodococcus catalytic tried is donated from E141, a model of the enzyme cocrystallized with sodium iodide shows two iodide binding sites; one that defines the normal substrate and product-binding site and a second within the active site region. In the substrate and product complexes, the halogen binds to the Xanthobacter enzyme via hydrogen bonds with the (NH)-H-eta of both W125 and W175. The Rhodococcus enzyme does not have a tryptophan analogous to W175. Instead, bound halide is stabilized with hydrogen bonds to the (NH)-H-eta of W118 and to (NH)-H-delta of N52, It appears that when cocrystallized with NaI the Rhodococcus enzyme has a rare stable S-I covalent bond to S-y of C187. C1 Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Theory, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Dow Chem Co, Midland, MI 48674 USA. RP Unkefer, CJ (reprint author), Univ Calif Los Alamos Natl Lab, Div Life Sci, MS G 758, Los Alamos, NM 87545 USA. RI Terwilliger, Thomas/K-4109-2012; Peat, Thomas/F-9817-2010; Newman, Janet/D-1857-2011; OI Terwilliger, Thomas/0000-0001-6384-0320; Peat, Thomas/0000-0002-6488-0831; Newman, Janet/0000-0003-2666-3219; Holmes, Ian/0000-0001-7639-5369 NR 51 TC 120 Z9 126 U1 2 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD DEC 7 PY 1999 VL 38 IS 49 BP 16105 EP 16114 DI 10.1021/bi9913855 PG 10 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 263TK UT WOS:000084141200009 PM 10587433 ER PT J AU Bluhm, EA Bauer, E Chamberlin, RM Abney, KD Young, JS Jarvinen, GD AF Bluhm, EA Bauer, E Chamberlin, RM Abney, KD Young, JS Jarvinen, GD TI Surface effects on cation transport across porous alumina membranes SO LANGMUIR LA English DT Article ID NANOFILTRATION MEMBRANES; SELECTIVITY; REJECTION AB Transport behavior of monovalent and divalent solutes across mesoporous Anopore gamma-alumina membranes was investigated as a function of pore diameter, pH, ionic strength, and nature of the salt or complexing species in solution. Radiotracers Cs-137, Sr-85, Na-22, and Ca-45 were present in the feed solutions at very low concentrations, ranging from 10(-9) to 10(-12) M and total salt concentrations from 0.1 to 10(-4) M. The divalent cations Ca2+ and Sr2+ exhibit lower diffusion rates (3-7 times slower) than the monovalent cations Cs+ and Na+ for membranes with 20 nm diameter pores. Differences between monovalent and divalent cation diffusion rates for the membranes can be explained in terms of a Donnan exclusion effect from the positively charged alumina surface. The rate of Sr2+ transport across the 20 nm alumina membranes was greatly increased by raising the pH (reducing the membrane surface charge) from 5 to 8 for both the feed and receive sides. Increased ionic strengths and the addition of complexing agents or specific salt solutions also facilitated divalent ion transport. Diffusion coefficients for divalent cations increased 3-fold for the 100 nm pore diameter membranes. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Nucl Mat Technol, Los Alamos, NM 87545 USA. RP Abney, KD (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, MS J514, Los Alamos, NM 87545 USA. RI Chamberlin, Rebecca/A-1335-2011 OI Chamberlin, Rebecca/0000-0001-6468-7778 NR 18 TC 60 Z9 60 U1 0 U2 16 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD DEC 7 PY 1999 VL 15 IS 25 BP 8668 EP 8672 DI 10.1021/la9902441 PG 5 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 263GK UT WOS:000084116900020 ER PT J AU Grigoriev, IV Kim, SH AF Grigoriev, IV Kim, SH TI Detection of protein fold similarity based on correlation of amino acid properties SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID MYCOPLASMA-GENITALIUM PROTEINS; SECONDARY-STRUCTURE; STRUCTURE PREDICTION; SEQUENCE; RECOGNITION; ALIGNMENT; DATABASE; MATRICES; SEARCH; CLASSIFICATION AB An increasing number of proteins with weak sequence similarity have bean found to assume similar three-dimensional fold and often have similar or related biochemical or biophysical functions. We propose a method for detecting the fold similarity between two proteins with low sequence similarity based on their amino acid properties alone. The method, the proximity correlation matrix (PCM) method, is built on the observation that the physical properties of neighboring amino acid residues in sequence at structurally equivalent positions of two proteins of similar fold are often correlated even when amino acid sequences are different. The hydrophobicity is shown to be the most strongly correlated property for all protein fold classes. The PCM method was tested on 420 proteins belonging to 64 different known folds, each having at least three proteins with little sequence similarity. The method was able to detect fold similarities for 40% of the 420 sequences. Compared with sequence comparison and several fold-recognition methods, the method demonstrates good performance in detecting fold similarities among the proteins with low sequence identity. Applied to the complete genome of Methanococcus jannaschii, the method recognized the folds for 22 hypothetical proteins. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, E O Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Kim, SH (reprint author), Univ Calif Berkeley, Melvin Calvin Lab 220, Berkeley, CA 94720 USA. NR 36 TC 27 Z9 27 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 DEC 7 PY 1999 VL 96 IS 25 BP 14318 EP 14323 DI 10.1073/pnas.96.25.14318 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 263XC UT WOS:000084149700034 PM 10588703 ER PT J AU Miksovska, J Schiffer, M Hanson, DK Sebban, P AF Miksovska, J Schiffer, M Hanson, DK Sebban, P TI Proton uptake by bacterial reaction centers: The protein complex responds in a similar manner to the reduction of either quinone acceptor SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE proton transfer; site-specific mutagenesis; membrane protein; water channel ID PHOTOSYNTHETIC REACTION CENTERS; CARBONIC-ANHYDRASE-V; RHODOBACTER-SPHAEROIDES; RHODOPSEUDOMONAS-VIRIDIS; ELECTRON-TRANSFER; BINDING-SITE; STRUCTURAL-CHANGES; SECONDARY QUINONE; Q(B); PATHWAY AB In bacterial photosynthetic reaction centers, the protonation events associated with the different reduction states of the two quinone molecules constitute intrinsic probes of both the electrostatic interactions and the different kinetic events occurring within the protein in response to the light-generated introduction of a charge. The kinetics and stoichiometries of proton uptake on formation of the primary semiquinone Q(A)(-) and the secondary acceptor Q(B)(-) after the first end second flashes have been measured, at pH 7.5, in reaction centers from genetically modified strains and from the wild type. The modified strains are mutated at the L212Glu and/or at the L213Asp sites near Q(B); some of them carry additional mutations distant from the quinone sites (M231Arg --> Leu, M43Asn --> Asp, M5Asn --> Asp) that compensate for the loss of L213Asp. Our data show that the mutations perturb the response of the protein system to the formation of a semiquinone, how distant compensatory mutations fan restore the normal response, and the activity of a tyrosine residue (M247Ala --> Tyr) in increasing and accelerating proton uptake. The data demonstrate a direct correlation between the kinetic events of proton uptake that are observed with the formation of either Q(A)(-) or Q(B)(-), suggesting that the same residues respond to the generation of either semiquinone species. Therefore, the efficiency of transferring the first proton to Q(B) is evident from examination of the pattern of H+/Q(A)(-) proton uptake. This delocalized response of the protein complex to the introduction of a charge is coordinated by an interactive network that links the Q(-) species, polarizable residues, and numerous water molecules that are located in this region of the reaction center structure. This could be a general property of transmembrane redox proteins that couple electron transfer to proton uptake/release reactions. C1 CNRS, Ctr Genet Mol, F-91198 Gif Sur Yvette, France. Argonne Natl Lab, Biosci Div, Argonne, IL 60439 USA. RP Sebban, P (reprint author), CNRS, Ctr Genet Mol, Bat 24, F-91198 Gif Sur Yvette, France. NR 43 TC 31 Z9 31 U1 0 U2 1 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 DEC 7 PY 1999 VL 96 IS 25 BP 14348 EP 14353 DI 10.1073/pnas.96.25.14348 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 263XC UT WOS:000084149700039 PM 10588708 ER PT J AU Foltyn, SR Jia, QX Arendt, PN Kinder, L Fan, Y Smith, JF AF Foltyn, SR Jia, QX Arendt, PN Kinder, L Fan, Y Smith, JF TI Relationship between film thickness and the critical current of YBa2Cu3O7-delta-coated conductors SO APPLIED PHYSICS LETTERS LA English DT Article ID DEPOSITION AB During the development of YBa2Cu3O7-delta (YBCO) coatings on flexible metal tapes, it has become evident that the achievable critical current (I-c) reaches a maximum value of about 200 A per cm of conductor width at a coating thickness of 1-2 mu m. Additional YBCO beyond this thickness can actually reduce I-c. To investigate, critical current density (J(c)) has been measured for samples with YBCO ranging from 0.39 to 6.3 mu m in thickness. Several films were thinned by ion milling and remeasured with two significant results: almost no supercurrent is carried at thickness levels above 2 mu m; and for films thicker than 3 mu m, J(c) is drastically reduced near the substrate as well. (C) 1999 American Institute of Physics. [S0003-6951(99)04249-7]. C1 Univ Calif Los Alamos Natl Lab, Superconduct Technol Ctr, Los Alamos, NM 87545 USA. RP Foltyn, SR (reprint author), Univ Calif Los Alamos Natl Lab, Superconduct Technol Ctr, Mail Stop K763, Los Alamos, NM 87545 USA. RI Jia, Q. X./C-5194-2008 NR 13 TC 181 Z9 186 U1 3 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 DEC 6 PY 1999 VL 75 IS 23 BP 3692 EP 3694 DI 10.1063/1.125431 PG 3 WC Physics, Applied SC Physics GA 259UR UT WOS:000083912800034 ER PT J AU Schlenga, K McDermott, R Clarke, J de Souza, RE Wong-Foy, A Pines, A AF Schlenga, K McDermott, R Clarke, J de Souza, RE Wong-Foy, A Pines, A TI Low-field magnetic resonance imaging with a high-T-c dc superconducting quantum interference device SO APPLIED PHYSICS LETTERS LA English DT Article ID MAGNETOMETER; NOISE; MRI AB A spectrometer incorporating a high transition temperature dc superconducting quantum interference device (SQUID) is used to obtain nuclear magnetic resonance signals from protons in mineral oil at room temperature in fields up to 3 mT. The spatial separation between the SQUID magnetometer at 77 K and the sample at room temperature is less than 1 mm. At 2 mT, the signal is easily resolved in a single scan. Two-dimensional images of samples consisting of pieces of lucite or glass immersed in mineral oil are obtained at 2 mT. (C) 1999 American Institute of Physics. [S0003-6951(99)03649-9]. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Schlenga, K (reprint author), Bruker Analyt GMBH, Wikingerstr 13, D-76189 Karlsruhe, Germany. NR 19 TC 51 Z9 52 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 DEC 6 PY 1999 VL 75 IS 23 BP 3695 EP 3697 DI 10.1063/1.125432 PG 3 WC Physics, Applied SC Physics GA 259UR UT WOS:000083912800035 ER PT J AU Rokhinson, LP Chen, CJ Choi, KK Tsui, DC Vawter, GA Yan, L Jiang, M Tamir, T AF Rokhinson, LP Chen, CJ Choi, KK Tsui, DC Vawter, GA Yan, L Jiang, M Tamir, T TI Optimization of blazed quantum-grid infrared photodetectors SO APPLIED PHYSICS LETTERS LA English DT Article ID PERFORMANCE; DIFFRACTION; DEPTH AB In a quantum-grid infrared photodetector (QGIP), the active multiple quantum well material is patterned into a grid structure. The purposes of the grid are, on the one hand, to create additional lateral electron confinement and, on the other, to convert part of the incident light into parallel propagation. With these two unique functions, a QGIP allows intersubband transition to occur in all directions. In this work, we focused on improving the effectiveness of a QGIP in redirecting the propagation of light using a blazed structure. The optimization of the grid parameters in terms of the blaze angle and the periodicity was performed by numerical simulation using the modal transmission-line theory and verified by experiment. With a blazed structure, the sensitivity of a QGIP can be improved by a factor of 1.8 compared with a regular QGIP with rectangular profiles. (C) 1999 American Institute of Physics. [S0003-6951(99)02049-5]. C1 Princeton Univ, Dept Elect Engn, Princeton, NJ 08544 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Polytech Univ, Dept Elect Engn, Brooklyn, NY 11201 USA. RP Rokhinson, LP (reprint author), Princeton Univ, Dept Elect Engn, Princeton, NJ 08544 USA. RI Choi, Kwong-Kit/K-9205-2013 NR 15 TC 4 Z9 4 U1 0 U2 0 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 DEC 6 PY 1999 VL 75 IS 23 BP 3701 EP 3703 DI 10.1063/1.125434 PG 3 WC Physics, Applied SC Physics GA 259UR UT WOS:000083912800037 ER PT J AU Setlow, RB AF Setlow, RB TI The US National Research Council's views of the radiation hazards in space SO MUTATION RESEARCH-FUNDAMENTAL AND MOLECULAR MECHANISMS OF MUTAGENESIS LA English DT Article; Proceedings Paper CT International-Space-Lifesciences-Working-Group-on-Radiation-Biology Results of a Workshop CY NOV, 1997 CL BANFF, CANADA SP Int Space Lifesciences Working Grp Radiat Biology DE high-energy high-atomic-number nuclei; deterministic effects; stochastic effects; dosimetry; cancer induction; central nervous system effects AB The author was the Chairman of a Task Group on the Biological Effects of Space Radiation formed as a result of discussions between NASA and the U.S. National Research Council's Committee on Space Biology and Medicine - a committee under the U.S. National Research Council's Space Studies Board. The Task Group was asked to review current knowledge on the effects of long-term exposure to radiation in space and to consider NASA radiation shielding requirements for orbital and interplanetary spacecraft. The group was charged with assessing the adequacy of NASA planning for the protection of humans from radiation in space and with making recommendations regarding needed research and/or new shielding requirements. This manuscript is a summary of the findings and recommendations of the Task Group. Beyond the protection of the Earth's atmosphere and its magnetosphere, the exposure to ionizing radiations far exceeds that on Earth. Of all the risks astronauts may face, this one is probably the most straightforward to control - by providing adequate shielding. However, because shielding adds weight, cost and complexity to space vehicles, it is important for designers to have a good quantitative understanding of the true risk and its degree of uncertainty so as not to under- or overshield spacecrafts. The extrapolations from our knowledge of ionizing radiation effects of low linear energy transfer (LET) to the risks from high-atomic-number high-energy energetic (HZE) cosmic rays are very uncertain because the necessary experiments on the effects of such particles have not been carried out and the extrapolation from low-LET to very high-LET has great uncertainties. These uncertainties were enumerated by the Task Group, and the types of experiments needed to minimize the uncertainties were described. The report found that, because of the small amounts of available time for biological research at HZE accelerators, it would take more than a decade of effort to obtain the answers to a narrow set of key questions that would facilitate reduction in risks and identification of the types of shielding needed. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Setlow, RB (reprint author), Brookhaven Natl Lab, Dept Biol, Box 5000, Upton, NY 11973 USA. NR 13 TC 21 Z9 26 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0027-5107 J9 MUTAT RES-FUND MOL M JI Mutat. Res.-Fundam. Mol. Mech. Mutagen. PD DEC 6 PY 1999 VL 430 IS 2 BP 169 EP 175 DI 10.1016/S0027-5107(99)00127-X PG 7 WC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology SC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology GA 268BU UT WOS:000084395100002 PM 10631330 ER PT J AU Rossbach, D Wilson, AN Barton, C Carpenter, MP Cullen, DM Hubel, H Janssens, RVF King, SL Korichi, A Reed, AT AF Rossbach, D Wilson, AN Barton, C Carpenter, MP Cullen, DM Hubel, H Janssens, RVF King, SL Korichi, A Reed, AT TI Superdeformation in Pb-193: Observation of three additional excited bands SO NUCLEAR PHYSICS A LA English DT Article DE superdeformation; cranked shell model; g factors; configurations ID QUADRUPOLE-MOMENTS; NUCLEI; TRANSITIONS; STATES; SPIN AB The superdeformed nucleus Pb-193 has been studied following a heavy-ion fusion-evaporation reaction with the Gammasphere spectrometer array. Three new superdeformed bands, two of them probably signature partners, have been observed, bringing the total number of superdeformed bands known in this nucleus to nine. An estimate of the g-factor associated with one of the previously known pairs of strongly coupled excited bands has been made, confirming their configuration. The properties of the bands are compared with the results of cranked shell model calculations; good agreement is found and configurations are assigned to each band. The two new signature partner bands are suggested to be based on the two signatures of the [512]5/2 neutron orbital. The third new band is probably based on the 7(3)' intruder orbital. In addition, the high-energy region of the spectrum in coincidence with the yrast superdeformed bands has been carefully studied. The current data provide no evidence for the previously reported transitions linking the superdeformed and normal-deformed states with energies around 2.2-2.4 MeV. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Bonn, Inst Strahlen & Kernphys, D-53115 Bonn, Germany. Yale Univ, WNSL, New Haven, CT 06520 USA. Argonne Natl Lab, Argonne, IL 60439 USA. CSNSM Orsay, F-91405 Orsay, France. Univ Liverpool, Dept Phys, Liverpool L69 7ZE, Merseyside, England. RP Rossbach, D (reprint author), Univ Bonn, Inst Strahlen & Kernphys, Nussallee 14-16, D-53115 Bonn, Germany. RI Carpenter, Michael/E-4287-2015; OI Carpenter, Michael/0000-0002-3237-5734; Wilson, Anna/0000-0001-6928-1689 NR 20 TC 8 Z9 8 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD DEC 6 PY 1999 VL 660 IS 4 BP 393 EP 405 DI 10.1016/S0375-9474(99)00415-7 PG 13 WC Physics, Nuclear SC Physics GA 271ZQ UT WOS:000084625900002 ER PT J AU Cheng, HC Matchev, KT AF Cheng, HC Matchev, KT TI New Higgs signals from flavor physics in large extra dimensions SO NUCLEAR PHYSICS B LA English DT Article DE Higgs boson; large extra dimensions; flavor theory ID STANDARD MODEL; COLLISIONS; HIERARCHY; COLLIDERS; DECAYS AB In a realistic theory with large extra dimensions and TeV scale gravity, there are often other particles living in the extra dimensions in addition to gravitons. A well-motivated candidate is the flavon in a flavor theory which explains the smallness of the fermion masses by the large volume of the extra dimensions. The flavon interactions involve the Higgs field and can therefore give rise to new mechanisms of Higgs boson production. We study these new Higgs signals, including both real flavon emission and virtual flavon exchange. They could provide powerful probes of the string scale which are comparable to the extensively studied graviton production, if the flavons and the graviton feel the same number of extra dimensions. If the flavons only live in a subspace of the extra dimensions, they can yield even stronger bounds and may generate spectacular displaced vertex signals. Our study also applies to a four-dimensional flavor theory with light flavons as well as to any theory with bulk scalar fields coupled to the Higgs and fermions. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Fermilab Natl Accelerator Lab, Dept Theoret Phys, Batavia, IL 60510 USA. RP Fermilab Natl Accelerator Lab, Dept Theoret Phys, Batavia, IL 60510 USA. NR 48 TC 3 Z9 3 U1 2 U2 3 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 DEC 6 PY 1999 VL 563 IS 1-2 BP 21 EP 44 DI 10.1016/S0550-3213(99)00599-4 PG 24 WC Physics, Particles & Fields SC Physics GA 268BB UT WOS:000084393500002 ER PT J AU Bardakci, K AF Bardakci, K TI Conformal models of Thirring type and the affine Virasoro construction SO NUCLEAR PHYSICS B LA English DT Article DE conformal theories; Thirring model AB We investigate a class of models in 1 + 1 dimensions with four fermion interaction term. At each order of the perturbation expansion, the models are ultraviolet finite and Lorentz non-invariant. We show that for certain privileged values of the coupling constants, Lorentz symmetry is restored, and indeed the model tunas out to be conformally invariant. This phenomenon is both quantum mechanical and non-perturbative. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Theoret Phys Grp, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Bardakci, K (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NR 15 TC 0 Z9 0 U1 0 U2 0 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 DEC 6 PY 1999 VL 563 IS 1-2 BP 437 EP 447 DI 10.1016/S0550-3213(99)00547-7 PG 11 WC Physics, Particles & Fields SC Physics GA 268BB UT WOS:000084393500019 ER PT J AU Kincaid, K Gerlach, CP Giesbrecht, GR Hagadorn, JR Whitener, GD Shafir, A Arnold, J AF Kincaid, K Gerlach, CP Giesbrecht, GR Hagadorn, JR Whitener, GD Shafir, A Arnold, J TI Synthesis, structure, and coordination chemistry of a tridentate, six-electron-donor amidinate ligand SO ORGANOMETALLICS LA English DT Article ID CRYSTAL-STRUCTURES; COMPLEXES; BENZYL; DERIVATIVES; ALUMINUM; TITANIUM AB The coordination chemistry of ancillary amidinate ligands with a pendant pyridine functionality is described. Reaction of p-toluoyl- or p-Bu-t-benzoyl chloride with 2-aminoethylpyridine generates the amides 2-Py-(CH2)(2)NHCO(p-RPh) (R = Me 1a; Bu-t 1b); these amides are then converted to the amidines 2-Py-(CH2)(2)NHC(p-RPh)NR' (R = Me, R' = Ph (2a) ((LH)-H-Me); R = tBu, R' = 3,5-dimethylphenyl (2b) ((LH)-H-tBu)) by reaction with PCl5 followed by R'NH2. The amidines 2a,b were characterized by H-1 NMR and IR spectroscopy and elemental analyses, and 2b was characterized by X-ray crystallography. Reaction of 2a or 2b with homoleptic metal-alkyls or -amides yields the mono- or bis(amidinate) complexes (L-Me)(2)Mg (3a), (L-tBu)AlMe2 (4), (L-tBu)Zr(CH2Ph)(3) (5), and (L-Me)(2)La[N(SiMe3)(2)] (6). All metal complexes were characterized by 1H NMR and IR spectroscopy, elemental analyses, and X-ray crystallography. The X-ray crystal structures of compounds 3-6 show them to be monomeric, with the pendant pyridine coordinated intramolecularly in all cases. The tridentate amidinate coordinates meridionally to the metal center except in the case of the lanthanum derivative 6, where an approximate facial geometry is observed. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Arnold, J (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Shafir, Alexandr/D-1676-2009; Arnold, John/F-3963-2012 OI Shafir, Alexandr/0000-0002-8127-2299; Arnold, John/0000-0001-9671-227X NR 32 TC 73 Z9 73 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD DEC 6 PY 1999 VL 18 IS 25 BP 5360 EP 5366 DI 10.1021/om990365w PG 7 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA 264GH UT WOS:000084171900022 ER PT J AU Huang, RL Guzei, IA Espenson, JH AF Huang, RL Guzei, IA Espenson, JH TI Two routes to bis(mu-diphenylphosphino)methane diplatinum halides bridged by sulfur monoxide SO ORGANOMETALLICS LA English DT Article ID COMPLEXES; BIS(DIPHENYLPHOSPHINO)METHANE; OXIDATION; DIOXIDE; SULFIDE AB The new compounds Pt-2(mu-diphenylphosphinomethane)(2)(mu-SO)X-2, with X = Cl and I, have been prepared and characterized. One route was to use Pt-2(mu-dppm)(2)X-2 to trap the sulfur monoxide Liberated from decomposition of a sultine intermediate formed from the oxidation. of a thioketone sulfoxide with hydrogen peroxide, catalyzed by CH3ReO3 (MTO). The second and preferable route consists of the oxidation of Pt-2(mu-dppm)(2)(mu-S)X-2 With hydrogen peroxide, catalyzed by CH3ReO3 (MTO). The X-ray structural analysis of Pt-2(mu-dppm)(2)(mu-SO)Cl-2 showed that it has an "A-frame" structure in. which the bridge sulfur atom has the geometry of a distorted trigonal bipyramid. 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 27 TC 16 Z9 16 U1 1 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD DEC 6 PY 1999 VL 18 IS 25 BP 5420 EP 5422 DI 10.1021/om9905815 PG 3 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA 264GH UT WOS:000084171900030 ER PT J AU Abdurashitov, JN Bowles, TJ Cherry, ML Cleveland, BT Davis, R Elliott, SR Gavrin, VN Girin, SV Gorbachev, VV Ibragimova, TV Kalikhov, AV Khairnasov, NG Knodel, TV Lande, K Mirmov, IN Nico, JS Shikhin, AA Teasdale, WA Veretenkin, EP Vermul, VM Wark, DL Wildenhain, PS Wilkerson, JF Yants, VE Zatsepin, GT AF Abdurashitov, JN Bowles, TJ Cherry, ML Cleveland, BT Davis, R Elliott, SR Gavrin, VN Girin, SV Gorbachev, VV Ibragimova, TV Kalikhov, AV Khairnasov, NG Knodel, TV Lande, K Mirmov, IN Nico, JS Shikhin, AA Teasdale, WA Veretenkin, EP Vermul, VM Wark, DL Wildenhain, PS Wilkerson, JF Yants, VE Zatsepin, GT CA SAGE Collaboration TI Measurement of the solar neutrino capture rate by SAGE and implications for neutrino oscillations in vacuum SO PHYSICAL REVIEW LETTERS LA English DT Article ID FLUX AB The Russian-American solar neutrino experiment has measured the capture rate of neutrinos on metallic gallium in a radiochemical experiment at the Baksan Neutrino Observatory. Eight years of measurement give the result 67.2(-7.0-3.0)(+7.2+3.5) solar neutrino units, where the uncertainties are statistical and systematic, respectively. The restrictions these results impose on vacuum neutrino oscillation parameters are given. C1 Russian Acad Sci, Inst Nucl Res, Moscow 117312, Russia. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Louisiana State Univ, Baton Rouge, LA 70803 USA. Univ Penn, Philadelphia, PA 19104 USA. Univ Washington, Seattle, WA 98195 USA. NIST, Gaithersburg, MD 20899 USA. RP Abdurashitov, JN (reprint author), Russian Acad Sci, Inst Nucl Res, 60th October Anniversary Prospect 7, Moscow 117312, Russia. RI Abdurashitov, Dzhonrid/B-2206-2014; Yants, Viktor/C-1038-2014; OI Abdurashitov, Dzhonrid/0000-0002-1577-1364; Wilkerson, John/0000-0002-0342-0217 NR 17 TC 151 Z9 151 U1 1 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 DEC 6 PY 1999 VL 83 IS 23 BP 4686 EP 4689 DI 10.1103/PhysRevLett.83.4686 PG 4 WC Physics, Multidisciplinary SC Physics GA 261PU UT WOS:000084018200003 ER PT J AU Smolanczuk, R AF Smolanczuk, R TI Production of even-even superheavy nuclei in cold fusion reactions SO PHYSICAL REVIEW LETTERS LA English DT Article ID SPONTANEOUS-FISSION; ELEMENTS; ISOTOPES AB We investigate the possibilities of the formation of even-even superheavy nuclei in the cold fusion reactions Pb-207(125)(HI,1n). We reproduce the measured cross sections of the reactions Pb-207(125)(Ti-50(28),1n)(256)Rf(152), Pb-207(125)(Cr-54(30),1n)(260)Sg(154), and Pb-207(125)(Fe-58(32),1n)(264)Hs(156) within a factor of 2.9 on average. We predict the optimal bombarding energies and the formation cross sections of even-even superheavy nuclei with Z = 110-120. C1 Soltan Inst Nucl Studies, Nucl Theory Dept, PL-00681 Warsaw, Poland. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Smolanczuk, R (reprint author), Soltan Inst Nucl Studies, Nucl Theory Dept, Hoza 69, PL-00681 Warsaw, Poland. NR 30 TC 19 Z9 19 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 DEC 6 PY 1999 VL 83 IS 23 BP 4705 EP 4708 DI 10.1103/PhysRevLett.83.4705 PG 4 WC Physics, Multidisciplinary SC Physics GA 261PU UT WOS:000084018200008 ER PT J AU Kwiat, PG White, AG Mitchell, JR Nairz, O Weihs, G Weinfurter, H Zeilinger, A AF Kwiat, PG White, AG Mitchell, JR Nairz, O Weihs, G Weinfurter, H Zeilinger, A TI High-efficiency quantum interrogation measurements via the quantum Zeno effect SO PHYSICAL REVIEW LETTERS LA English DT Article ID PARADOX AB The phenomenon of quantum interrogation allows one to optically detect the presence of an absorbing object, without the measuring light interacting with it. In an application of the quantum Zeno effect, the object inhibits the otherwise coherent evolution of the light, such that the probability that an interrogating photon is absorbed can in principle be arbitrarily small. We have implemented this technique, achieving efficiencies of up to 73%, and consequently exceeding the 50% theoretical maximum of the original "interaction-free" measurement proposal. We have also predicted and experimentally verified a previously unsuspected dependence on loss. C1 Los Alamos Natl Lab, Div Phys, Los Alamos, NM 87545 USA. Univ Innsbruck, Inst Expt Phys, A-6020 Innsbruck, Austria. RP Kwiat, PG (reprint author), Los Alamos Natl Lab, Div Phys, P-23, Los Alamos, NM 87545 USA. EM Kwiat@lanl.gov RI Weinfurter, Harald/F-8225-2015; White, Andrew/A-1088-2009; Weihs, Gregor/G-2564-2013 OI Weinfurter, Harald/0000-0001-6882-3909; White, Andrew/0000-0001-9639-5200; Weihs, Gregor/0000-0003-2260-3008 NR 19 TC 95 Z9 97 U1 2 U2 11 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 DEC 6 PY 1999 VL 83 IS 23 BP 4725 EP 4728 DI 10.1103/PhysRevLett.83.4725 PG 4 WC Physics, Multidisciplinary SC Physics GA 261PU UT WOS:000084018200013 ER PT J AU Dugdale, SB Alam, MA Wilkinson, I Hughes, RJ Fisher, IR Canfield, PC Jarlborg, T Santi, G AF Dugdale, SB Alam, MA Wilkinson, I Hughes, RJ Fisher, IR Canfield, PC Jarlborg, T Santi, G TI Nesting properties and anisotropy of the Fermi surface of LuNi2B2C SO PHYSICAL REVIEW LETTERS LA English DT Article ID UPPER CRITICAL-FIELD; SUPERCONDUCTING LUNI2B2C; POSITRON-ANNIHILATION; ELECTRONIC-STRUCTURE; MAGNETIC-STRUCTURE; T-C; YNI2B2C; LATTICE; STATE; SCATTERING AB The rare-earth nickel borocarbides, with the generic formula RNi2B2C, have recently been shown to display a rich variety of phenomena. Most striking has been the competition between, and even coexistence of, antiferromagnetism and superconductivity. We have measured the Fermi surface (FS) of LuNi2B2C, and shown that it possesses nesting features capable of explaining some of the phenomena experimentally observed. In particular, it had previously been conjectured that a particular sheet of FS is responsible for the modulated magnetic structures manifest in some of the series. We report the first direct experimental observation of this sheet. C1 Univ Bristol, HH Wills Phys Lab, Bristol BS8 1TL, Avon, England. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. Univ Geneva, Dept Phys Mat Condensee, CH-1211 Geneva 4, Switzerland. RP Dugdale, SB (reprint author), Univ Bristol, HH Wills Phys Lab, Tyndall Ave, Bristol BS8 1TL, Avon, England. RI Dugdale, Stephen/F-4066-2011; Canfield, Paul/H-2698-2014 OI Dugdale, Stephen/0000-0002-2738-2235; NR 45 TC 90 Z9 90 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 DEC 6 PY 1999 VL 83 IS 23 BP 4824 EP 4827 DI 10.1103/PhysRevLett.83.4824 PG 4 WC Physics, Multidisciplinary SC Physics GA 261PU UT WOS:000084018200038 ER PT J AU Kopnin, NB Vinokur, VM AF Kopnin, NB Vinokur, VM TI Effects of pinning on the flux flow Hall resistivity SO PHYSICAL REVIEW LETTERS LA English DT Article ID SCALING BEHAVIOR; COLUMNAR DEFECTS; TRANSVERSE FORCE; STATE; SUPERCONDUCTORS; DEPENDENCE; FILMS AB We demonstrate that pinning strongly renormalizes both longitudinal and Hall resistivity in the flux flow regime. Using a simple model for the pinning potential we show that the magnitude of the vortex contribution to the Hall voltage decreases with increase in the pinning strength. The Hall resistivity rho(xy) scales as rho(xx)(2) only for a weak pinning. On the contrary, a strong pinning breaks the scaling relation and can even result in a sign reversal of rho(xy). C1 LD Landau Theoret Phys Inst, Moscow 117334, Russia. Argonne Natl Lab, Argonne, IL 60439 USA. RP Kopnin, NB (reprint author), LD Landau Theoret Phys Inst, Kosygina 2, Moscow 117334, Russia. NR 11 TC 32 Z9 33 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 DEC 6 PY 1999 VL 83 IS 23 BP 4864 EP 4867 DI 10.1103/PhysRevLett.83.4864 PG 4 WC Physics, Multidisciplinary SC Physics GA 261PU UT WOS:000084018200048 ER PT J AU von Zimmermann, M Hill, JP Gibbs, D Blume, M Casa, D Keimer, B Murakami, Y Tomioka, Y Tokura, Y AF von Zimmermann, M Hill, JP Gibbs, D Blume, M Casa, D Keimer, B Murakami, Y Tomioka, Y Tokura, Y TI Interplay between charge, orbital, and magnetic order in Pr1-xCax/MnO3 SO PHYSICAL REVIEW LETTERS LA English DT Article ID X-RAY-SCATTERING; PR1-XCAXMNO3; DIFFRACTION AB We report resonant x-ray scattering studies of charge and orbital order in Pr1-xCaxMnO3 with x = 0.4 and 0.5. Below the ordering temperature, T-0 = 245 K, the charge and orbital order intensities follow the same temperature dependence, including an increase at the antiferromagnetic ordering temperature, T-N. High resolution measurements reveal, however, that long range orbital order is never achieved. Rather, an orbital domain state is formed. Above T-0, the charge order fluctuations are more highly correlated than the orbital fluctuations. We conclude that the charge order dl ives the orbital order at the transition. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. Max Planck Inst Festkorperforsch, D-70569 Stuttgart, Germany. High Energy Accelerator Res Org, Photon Factory, Inst Mat Struct Sci, Tsukuba, Ibaraki 3050801, Japan. Joint Res Ctr Atom Technol, Tsukuba, Ibaraki 3050046, Japan. Univ Tokyo, Dept Appl Phys, Tokyo 1130033, Japan. RP von Zimmermann, M (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RI Hill, John/F-6549-2011; Tokura, Yoshinori/C-7352-2009; Casa, Diego/F-9060-2016 NR 21 TC 106 Z9 106 U1 1 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 DEC 6 PY 1999 VL 83 IS 23 BP 4872 EP 4875 PG 4 WC Physics, Multidisciplinary SC Physics GA 261PU UT WOS:000084018200050 ER PT J AU Henning, PF Homes, CC Maslov, S Carr, GL Basov, DN Nikolic, B Strongin, M AF Henning, PF Homes, CC Maslov, S Carr, GL Basov, DN Nikolic, B Strongin, M TI Infrared studies of the onset of conductivity in ultrathin Pb films SO PHYSICAL REVIEW LETTERS LA English DT Article ID SUPERCONDUCTOR-INSULATOR TRANSITION; LOCALIZATION; YBA2CU3O7-DELTA; DESTRUCTION; SYSTEMS AB In this paper we report the first experimental measurement of the low-temperature, normal-state infrared conductivity of ultrathin quenched-condensed Pb films. For de sheet resistances such that omega tau << 1 the ac conductance increases with frequency but is in disagreement with the predictions of weak localization. We attribute this behavior to the effects of an inhomogeneous granular structure in these films when they are first formed, which is manifested at the very small probing scale of infrared measurements. Our data are consistent with predictions of two-dimensional percolation theory. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. SUNY Stony Brook, Dept Phys, Stony Brook, NY 11794 USA. RP Henning, PF (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RI Maslov, Sergei/C-2397-2009 OI Maslov, Sergei/0000-0002-3701-492X NR 24 TC 37 Z9 37 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 DEC 6 PY 1999 VL 83 IS 23 BP 4880 EP 4883 DI 10.1103/PhysRevLett.83.4880 PG 4 WC Physics, Multidisciplinary SC Physics GA 261PU UT WOS:000084018200052 ER PT J AU Viola, L Lloyd, S Knill, E AF Viola, L Lloyd, S Knill, E TI Universal control of decoupled quantum systems SO PHYSICAL REVIEW LETTERS LA English DT Article ID COMPUTATION; DECOHERENCE; CODES AB We show that if one can perform a restricted set of fast manipulations on a quantum system, one can implement a large class of dynamical evolutions by effectively removing or introducing selected Hamiltonians. The procedure can be used to achieve universal noise-tolerant control based on purely unitary open-loop transformations of the dynamics. As a result, it is in principle possible to perform noise-protected universal quantum computation using no extra space resources. C1 MIT, Dept Mech Engn, dArbeloff Lab Informat Syst & Technol, Cambridge, MA 02139 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Viola, L (reprint author), MIT, Dept Mech Engn, dArbeloff Lab Informat Syst & Technol, Cambridge, MA 02139 USA. NR 21 TC 218 Z9 220 U1 0 U2 18 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 DEC 6 PY 1999 VL 83 IS 23 BP 4888 EP 4891 DI 10.1103/PhysRevLett.83.4888 PG 4 WC Physics, Multidisciplinary SC Physics GA 261PU UT WOS:000084018200054 ER PT J AU Gross, AG Harmon, JE AF Gross, AG Harmon, JE TI What's right about scientific writing SO SCIENTIST LA English DT Editorial Material C1 Univ Minnesota, Minneapolis, MN 55455 USA. Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. RP Gross, AG (reprint author), Univ Minnesota, Minneapolis, MN 55455 USA. NR 4 TC 5 Z9 6 U1 0 U2 3 PU SCIENTIST INC PI PHILADELPHIA PA 3600 MARKET ST SUITE 450, PHILADELPHIA, PA 19104 USA SN 0890-3670 J9 SCIENTIST JI Scientist PD DEC 6 PY 1999 VL 13 IS 24 BP 20 EP 20 PG 1 WC Information Science & Library Science; Multidisciplinary Sciences SC Information Science & Library Science; Science & Technology - Other Topics GA 261PK UT WOS:000084017400015 ER PT J AU Bhatt, S Greenberg, D Leighton, T Liu, PF AF Bhatt, S Greenberg, D Leighton, T Liu, PF TI Tight bounds for on-line tree embeddings SO SIAM JOURNAL ON COMPUTING LA English DT Article DE graph embedding; randomized algorithm ID HYPERCUBES AB Tree-structured computations are relatively easy to process in parallel. As leaf processes are recursively spawned they can be assigned to independent processors in a multicomputer network. However, to achieve good performance the on-line mapping algorithm must maintain load balance, i.e., distribute processes equitably among processors. Additionally, the algorithm itself must be distributed in nature, and process allocation must be completed via message-passing with minimal communication overhead. This paper investigates bounds on the performance of deterministic and randomized algorithms for on-line tree embeddings. In particular, we study trade-offs between computation overhead (load imbalance) and communication overhead (message congestion). We give a simple technique to derive lower bounds on the congestion that any on-line allocation algorithm must incur in order to guarantee load balance. This technique works for both randomized and deterministic algorithms. We prove that the advantage of randomization is limited. Optimal bounds are achieved for several networks, including multidimensional grids and butterflies. C1 BELLCORE, Morristown, NJ 07960 USA. CALTECH, Pasadena, CA 91125 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. MIT, Cambridge, MA 02139 USA. Natl Chung Cheng Univ, Chiayi 621, Taiwan. RP Bhatt, S (reprint author), BELLCORE, 445 South St, Morristown, NJ 07960 USA. OI LIU, PANGFENG/0000-0002-5466-9960 NR 10 TC 3 Z9 3 U1 0 U2 0 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 0097-5397 J9 SIAM J COMPUT JI SIAM J. Comput. PD DEC 6 PY 1999 VL 29 IS 2 BP 474 EP 491 DI 10.1137/S0097539796308710 PG 18 WC Computer Science, Theory & Methods; Mathematics, Applied SC Computer Science; Mathematics GA 265XP UT WOS:000084271800008 ER PT J AU Shapira, Y AF Shapira, Y TI Multigrid for locally refined meshes SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article DE diffusion equation; discontinuous coefficients; local mesh refinement; multigrid method ID PARTIAL-DIFFERENTIAL EQUATIONS; MULTILEVEL ADAPTIVE METHODS; INDEFINITE PROBLEMS; ELLIPTIC PROBLEMS; PRECONDITIONERS; MULTIPROCESSORS; COEFFICIENTS; ALGORITHMS; SOLVER AB A multilevel method for the solution of finite element schemes on locally refined meshes is introduced. For isotropic diffusion problems, the condition number of the two-level method is bounded independently of the mesh size and the discontinuities in the diffusion coefficient. The curves of discontinuity need not be aligned with the coarse mesh. Indeed, numerical applications with 10 levels of local refinement yield a rapid convergence of the corresponding 10-level, multigrid V-cycle and other multigrid cycles which are more suitable for parallelism even when the discontinuities are invisible on most of the coarse meshes. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Shapira, Y (reprint author), Univ Calif Los Alamos Natl Lab, Mail Stop B-256, Los Alamos, NM 87545 USA. NR 29 TC 4 Z9 4 U1 0 U2 1 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 1064-8275 J9 SIAM J SCI COMPUT JI SIAM J. Sci. Comput. PD DEC 6 PY 1999 VL 21 IS 3 BP 1168 EP 1190 DI 10.1137/S1064827597316564 PG 23 WC Mathematics, Applied SC Mathematics GA 265XX UT WOS:000084272500020 ER PT J AU Erkmen, ZE AF Erkmen, ZE TI The effect of heat treatment on the morphology of D-Gun sprayed hydroxyapatite coatings SO JOURNAL OF BIOMEDICAL MATERIALS RESEARCH LA English DT Article DE detonation gun spraying; hydroxyapatite; heat-treatment; porosity; crystallinity ID TITANIUM; PHASE AB In this study, the morphology of the Hydroxyapatite (HA) coatings sprayed on Ti alloy samples by Detonation Gun Spray (D-Gun) and the effect of aging before and after heat treatment in physiological solution were observed. Cross-sectional porosity and percentages of amorphous and crystal phase were measured using optical, electron microscopy, and X-ray diffraction analysis. Differential Thermogravimetric Analysis (DTA) was performed to estimate the glass-crystalline phase transformation temperatures. Heat-treatment at 300, 500, 700, 800 and 1200 degrees C were carried out to confirm DTA results. As a final analysis, the aging effect using Ringer's solution for 1 week on heat-treated and non-heat-treated samples was measured, It was observed that, in D-Gun sprayed samples, the cross-sectional porosity stayed in the accepted 5% range as reported for other spraying techniques,(1-5) On the other hand, surface porosity measured using the water immersion method remained in the conventional porosity limit of 15% for non-heat-treated samples. Heat-treatment had a small influence on the porosity while the crystallinity increased considerably; in addition, aging had little effect on HA crystallinity for heat treated samples. This work showed that D-gun sprayed HA coatings had lower porosity and better integrity than other coatings, due to which we can expect better performance during in vivo applications. (C) 1999 John Wiley & Sons, Inc. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Erkmen, ZE (reprint author), Istanbul Univ, Dept Mat & Met Engn, Avcilar Campus, TR-34950 Istanbul, Turkey. NR 20 TC 22 Z9 22 U1 0 U2 1 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0021-9304 J9 J BIOMED MATER RES JI J. Biomed. Mater. Res. PD DEC 5 PY 1999 VL 48 IS 6 BP 861 EP 868 DI 10.1002/(SICI)1097-4636(1999)48:6<861::AID-JBM15>3.0.CO;2-H PG 8 WC Engineering, Biomedical; Materials Science, Biomaterials SC Engineering; Materials Science GA 257FQ UT WOS:000083772200015 PM 10556852 ER PT J AU Schnabel, RC Scott, BL Smith, WH Burns, CJ AF Schnabel, RC Scott, BL Smith, WH Burns, CJ TI Synthesis and structural characterization of uranium ansa-metallocene complexes containing organoimido functional groups; electronic effects of ancillary ligands SO JOURNAL OF ORGANOMETALLIC CHEMISTRY LA English DT Article DE uranium; organoimido; ansa-metallocene ID ORGANOACTINIDE COORDINATIVE UNSATURATION; ACTINIDE PHOSPHINIDENE COMPLEXES; VALENT ORGANOURANIUM COMPLEXES; X-RAY STRUCTURE; C-H ACTIVATION; REVERSIBLE 1,2-RH-ELIMINATION; HYDROCARBON ACTIVATION; CRYSTAL-STRUCTURES; CHEMISTRY; HYDRIDES AB Complexes of U(IV) employing the chelating bis(cyclopentadienyl) ligand sets [Me2Si(eta(5)-C5Me4)(2)](2-) and [Me2Si(eta(5)-C5Me4)(eta(5)-C5H4)](2-) have been prepared to examine their utility in generating organoimido complexes of uranium. The chloride complexes [Me2Si(C5Me4)(2)]UCl2. 2LiCl.4(Et2O) (1) and [Me2Si(C5Me4)(C5H4)]-UCl(2.)2LiCl . 4(THF) (2) may be generated at ro om temperature by reaction of UCl4 with the corresponding bis(cyclopentadienyl) dilithio salt in diethyl ether and tetrahydrofuran, respectively. Complex 1 may be recrystallized from toluene in the presence of TMEDA to yield the complex [Me2Si(C5Me4)(2)]U(mu-Cl-4){Li(TMEDA)}(2) (1.TMEDA). The molecular structure of this complex has been determined by single-crystal X-ray diffraction. Compounds 1 and 2 may be alkylated by Grignard reagents. While the dimethyl complex [Me2Si(C5Me4)(2)]UMe2 (3) may be isolated, the analogous complex and [Me2Si(C5Me4)(C5H4)]UMe2 appears to be thermally unstable. Benzyl derivatives employing both ligand sets (4, 5) have been prepared. These alkyl complexes are protonated by N,N'-diphenylhydrazine to yield phenylimido-containing products. Surprisingly, while reaction of compounds 3 or 4 with N,N'-diphenylhydrazine yields the expected U(VI) complex [Me2Si(C5Me4)(2)]U(NC6H5)(2), reactions employing 5 generate only the U(IV) monoimido dimer [Me2Si(C5Me4)(C5H4)]U(NC6H5)](2) (8). The molecular structure of 8 has been determined, the compound exists as a dimer with asymmetric organoimido bridging ligands. Electrochemical investigations of the chloride compounds 1 and 2 suggest that the ancillary ligands have the capacity to significantly alter the redox activity of the metal center. The use of electron-rich ancillary ligands appears to be important in the isolation of high-valent organouranium complexes. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Eckerd Coll, Dept Chem, St Petersburg, FL USA. Univ Calif Los Alamos Natl Lab, Nucl Mat Technol Div, Los Alamos, NM 87545 USA. RP Burns, CJ (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, POB 1663,MS J514, Los Alamos, NM 87545 USA. RI Scott, Brian/D-8995-2017 OI Scott, Brian/0000-0003-0468-5396 NR 52 TC 38 Z9 38 U1 0 U2 7 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0022-328X J9 J ORGANOMET CHEM JI J. Organomet. Chem. PD DEC 5 PY 1999 VL 591 IS 1-2 BP 14 EP 23 DI 10.1016/S0022-328X(99)00525-2 PG 10 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA 263HD UT WOS:000084118500003 ER PT J AU Hirata, S Head-Gordon, M AF Hirata, S Head-Gordon, M TI Time-dependent density functional theory within the Tamm-Dancoff approximation SO CHEMICAL PHYSICS LETTERS LA English DT Article ID ELECTRONICALLY EXCITED-STATES; CORRECT ASYMPTOTIC-BEHAVIOR; EXCITATION-ENERGIES; CONFIGURATION-INTERACTION; DYNAMIC POLARIZABILITIES; RESPONSE THEORY; EIGENVALUES; EXCHANGE; IMPLEMENTATION; FORMALDEHYDE AB A computationally simple method for molecular excited states, namely, the Tamm-Dancoff approximation to time-dependent density functional theory, is proposed and implemented. This method yields excitation energies for several closed-and open-shell molecules that are essentially of the same quality as those obtained from time-dependent density functional theory itself, when the same exchange-correlation functional is used. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Hirata, S (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 31 TC 669 Z9 673 U1 5 U2 67 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 DEC 3 PY 1999 VL 314 IS 3-4 BP 291 EP 299 DI 10.1016/S0009-2614(99)01149-5 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 264WD UT WOS:000084205200015 ER PT J AU Shannon, M Richardson, L Christian, A Handel, MA Thelen, MP AF Shannon, M Richardson, L Christian, A Handel, MA Thelen, MP TI Differential gene expression of mammalian SPO11/TOP6A homologs during meiosis SO FEBS LETTERS LA English DT Article DE SPO11/TOP6A homologs; meiosis ID DOUBLE-STRAND BREAKS; MEIOTIC RECOMBINATION; SACCHAROMYCES-CEREVISIAE; TOPOISOMERASE-II; GENERATION; CHROMOSOME; MECHANISM; PROTEINS; COMPLEX; MOUSE AB As the initiator of DNA double-strand breaks during meiosis in Saccharomyces cerevisiae, the SPO11 protein is essential for recombination. Similarity between SPO11 and archaebacterial TOP6A proteins points to evolutionary specialization of a DNA cleavage function for meiotic recombination, To determine whether this extends to mammals, we isolated and characterized mouse and human SPO11 cDNAs, Mammalian SPO11 genes were found to be expressed at high levels only in testis, wherein mouse Spell transcript is restricted primarily to meiotic germ cells and is maximally expressed at mid-pachynema, Mouse Spell is located near the distal end of chromosome 2, while human SPO11 is found in the homologous position of chromosome 20q13.2-13.3, a region that is amplified in some breast cancers. Sequence homology and differential expression together support a highly conserved role for SPO11 in the enzymatic cleavage of DNA that accompanies meiotic recombination, (C) 1999 Federation of European Biochemical Societies. C1 Univ Calif Lawrence Livermore Natl Lab, Mol & Struct Biol Div, Biol & Biotechnol Res Program, Livermore, CA 94550 USA. Univ Tennessee, Dept Biochem & Cellular & Mol Biol, Knoxville, TN 37996 USA. RP Thelen, MP (reprint author), Univ Calif Lawrence Livermore Natl Lab, Mol & Struct Biol Div, Biol & Biotechnol Res Program, L452,POB 808, Livermore, CA 94550 USA. RI Thelen, Michael/C-6834-2008; Thelen, Michael/G-2032-2014 OI Thelen, Michael/0000-0002-2479-5480; Thelen, Michael/0000-0002-2479-5480 FU NICHD NIH HHS [HD31376] NR 25 TC 35 Z9 37 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0014-5793 J9 FEBS LETT JI FEBS Lett. PD DEC 3 PY 1999 VL 462 IS 3 BP 329 EP 334 DI 10.1016/S0014-5793(99)01546-X PG 6 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 263XU UT WOS:000084151200020 PM 10622720 ER PT J AU Sivakumaran, K Kim, CH Tayon, R Kao, CC AF Sivakumaran, K Kim, CH Tayon, R Kao, CC TI RNA sequence and secondary structural determinants in a minimal viral promoter that directs replicase recognition and initiation of genomic plus-strand RNA synthesis SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE RNA replication; viral replicase; RNA promoter; RdRp; brome mosaic virus ID BROME MOSAIC-VIRUS; STEM-LOOP STRUCTURE; ROSS RIVER VIRUS; SUBGENOMIC RNA; MOTTLE VIRUS; NUCLEOTIDE-SEQUENCE; MUTATIONAL ANALYSIS; IN-VITRO; POLYMERASE; PURIFICATION AB Viral RNA replication provides a useful system to study the structure and function of RNAs and the mechanism of RNA synthesis from RNA templates. Previously we demonstrated that a 27 nt RNA from brome mosaic virus (BMV) can direct correct initiation of genomic plus-strand RNA synthesis by the BMV replicase. In this study, using biochemical, nuclear magnetic resonance, and thermodynamic analyses, we determined that the secondary structure of this 27 nt RNA can be significantly altered and retain the ability to direct RNA synthesis. In contrast, we find that position-specific changes in the RNA sequence will affect replicase recognition, modulate the polymerization process, and contribute to the differential accumulation of viral RNAs. These functional results are in agreement with the phylogenetic analysis of BMV and related viral sequences and suggest that a similar mechanism of RNA synthesis takes place for members of the alphavirus superfamily. (C) 1999 Academic Press. C1 Indiana Univ, Dept Biol, Bloomington, IN 47405 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Phys Biosci, Berkeley, CA 94720 USA. RP Kao, CC (reprint author), Indiana Univ, Dept Biol, Bloomington, IN 47405 USA. FU NIGMS NIH HHS [GM10840] NR 79 TC 44 Z9 46 U1 1 U2 1 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 DEC 3 PY 1999 VL 294 IS 3 BP 667 EP 682 DI 10.1006/jmbi.1999.3297 PG 16 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 264TH UT WOS:000084197200005 PM 10610788 ER PT J AU Reinherz, EL Tan, KM Tang, L Kern, P Liu, JH Xiong, Y Hussey, RE Smolyar, A Hare, B Zhang, RG Joachimiak, A Chang, HC Wagner, G Wang, JH AF Reinherz, EL Tan, KM Tang, L Kern, P Liu, JH Xiong, Y Hussey, RE Smolyar, A Hare, B Zhang, RG Joachimiak, A Chang, HC Wagner, G Wang, JH TI The crystal structure of a T cell receptor in complex with peptide and MHC class II SO SCIENCE LA English DT Review ID TOXIC LYMPHOCYTES-T; BOUND SINGLE PEPTIDES; MYELIN BASIC-PROTEIN; TCR FAB FRAGMENT; ALPHA-CHAIN; ANTIGEN RECEPTOR; 3-DIMENSIONAL STRUCTURE; BETA-CHAIN; SUPERANTIGEN RECOGNITION; POSITIVE SELECTION AB The crystal structure of a complex involving the D10 T cell receptor (TCR), 16-residue foreign peptide antigen, and the I-A(k) self major histocompatibility complex (MHC) class II molecule is reported at 3.2 angstrom resolution. The D10 TCR is oriented in an orthogonal mode relative to its peptide-MHC (pMHC) Ligand, necessitated by the amino-terminal extension of peptide residues projecting from the MHC class II antigen-binding groove as part of a mini beta sheet. Consequently, the disposition of D10 complementarity-determining region Loops is altered relative to that of most pMHCI-specific TCRs; the Latter TCRs assume a diagonal orientation, although with substantial variability. Peptide recognition, which involves P-1 to P8 residues, is dominated by the V alpha domain, which also binds to the class II MHC beta(1) helix. That docking is Limited to one segment of MHC-bound peptide offers an explanation for epitope recognition and altered peptide Ligand effects, suggests a structural basis for alloreactivity, and illustrates how bacterial superantigens can span the TCR-pMHCII surface. C1 Harvard Univ, Sch Med, Dana Farber Canc Inst, Immunobiol Lab, Boston, MA 02115 USA. Harvard Univ, Sch Med, Dept Med, Boston, MA 02115 USA. Harvard Univ, Sch Med, Dept Pathol, Boston, MA 02115 USA. Harvard Univ, Sch Med, Dept Pediat, Boston, MA 02115 USA. Harvard Univ, Sch Med, Dept Biol Chem & Mol Pharmacol, Boston, MA 02115 USA. Argonne Natl Lab, Biosci Div, Argonne, IL 60439 USA. RP Harvard Univ, Sch Med, Dana Farber Canc Inst, Immunobiol Lab, 44 Binney St, Boston, MA 02115 USA. EM ellis_reinherz@dfci.harvard.edu; jwang@red.dfci.harvard.edu FU NIAID NIH HHS [AI19807, AI/CA37581]; NIGMS NIH HHS [GM56008] NR 127 TC 322 Z9 330 U1 3 U2 11 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 EI 1095-9203 J9 SCIENCE JI Science PD DEC 3 PY 1999 VL 286 IS 5446 BP 1913 EP 1921 DI 10.1126/science.286.5446.1913 PG 9 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 261HH UT WOS:000084003400040 PM 10583947 ER PT J AU Chalmers, G Schalm, K AF Chalmers, G Schalm, K TI Quantization and scattering in the IIB SL(2,Z) covariant superstring SO JOURNAL OF HIGH ENERGY PHYSICS LA English DT Article DE superstrings and heterotic strings; string duality; supersymmetric effective theories ID IIB S-DUALITY; 4-GRAVITON AMPLITUDE; D-INSTANTONS; ONE-LOOP; SUPERGRAVITY; STRINGS; TENSION; BRANES AB We rewrite the SL(2; Z) covariant worldsheet action for the IIB string proposed by Townsend in a Polyakov form. In a at background the formalism yields separate (p; q) sectors. In each one the action is that of the IIB string action with the string slope parameter alpha' replaced by its SL(2; Z) analogue alpha'(pq). SL(2; Z) invariant graviton scattering amplitudes are obtained from those of the fundamental (1; 0) string by summing over the different sectors. The tree-level four-graviton amplitude in this formalism differs from a previously conjectured non-perturbative form; both yield the same expansion in order alpha'(3). C1 Argonne Natl Lab, Div High Energy Phys, Argonne, IL 60439 USA. SUNY Stony Brook, CN Yang Inst Theoret Phys, Stony Brook, NY 11794 USA. RP Argonne Natl Lab, Div High Energy Phys, 9700 S Cass Ave, Argonne, IL 60439 USA. EM chalmers@pc19.hep.anl.gov; konrad@insti.physics.sunysb.edu NR 27 TC 1 Z9 1 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 DEC 2 PY 1999 IS 10 AR 016 PG 15 WC Physics, Particles & Fields SC Physics GA 280RV UT WOS:000085116700016 ER PT J AU Grossman, Y Neubert, M Kagan, AL AF Grossman, Y Neubert, M Kagan, AL TI Trojan penguins and isospin violation in hadronic B decays SO JOURNAL OF HIGH ENERGY PHYSICS LA English DT Article DE weak decays; beyond standard model; CP violation ID DIRECT CP VIOLATION; SEMILEPTONIC BRANCHING RATIO; CKM-ANGLE-GAMMA; ELECTROWEAK PENGUINS; LEADING LOGARITHMS; STANDARD MODEL; B->PI-K DECAYS; HIGGS SECTOR; RESCATTERING; PHYSICS AB Some rare hadronic decays of B mesons, such as B --> pi K, are sensitive to isospin-violating contributions from physics beyond the Standard Model. Although commonly referred to as electroweak penguins, such contributions can often arise through tree-level exchanges of heavy particles, or through strong-interaction loop diagrams. The Wilson coefficients of the corresponding electroweak penguin operators are calculated in a large class of New Physics models, and in many cases are found not to be suppressed with respect to the QCD penguin coefficients. Several tests for these effects using observables in B+/- pi K decays are discussed, and nontrivial bounds on the couplings of the various New Physics models are derived. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Univ Cincinnati, Dept Phys, Cincinnati, OH 45221 USA. RP Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. EM yuval@slac.stanford.edu; neubert@slac.stanford.edu; kagan@physics.uc.edu NR 81 TC 44 Z9 44 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 DEC 2 PY 1999 IS 10 AR 029 PG 43 WC Physics, Particles & Fields SC Physics GA 280RV UT WOS:000085116700029 ER PT J AU Hollowood, TJ Khoze, VV Mattis, MP AF Hollowood, TJ Khoze, VV Mattis, MP TI Summing the instanton series in N=2 superconformal large-N QCD SO JOURNAL OF HIGH ENERGY PHYSICS LA English DT Article DE solitons monopoles and instantons; 1/N expansion; duality in gauge field theories; brane dynamics in gauge theories ID MULTIINSTANTON MEASURE; SUPERSYMMETRY AB We consider the multi-instanton collective coordinate integration measure in N = 2 supersymmetric SU(N) gauge theory with N-F fundamental hypermultiplets. In the large-N limit, at the superconformal point where N-F = 2N and all VEVs are turned off, the k-instanton moduli space collapses to a single copy of AdS(5) x S-1. The resulting k-instanton effective measure is proportional to root N-g(4)(Z) over cap(k)((6)), where (Z) over cap(k)((6)) is the partition function of N = (1;0) SYM theory in six dimensions reduced to zero dimensions. The multi-instanton can in fact be summed in closed form. As a hint of an AdS/CFT duality, with the usual relation between the gauge theory and string theory parameters, this precisely matches the normalization of the charge-k D-instanton measure in type IIB string theory compactified to six dimensions on K3 with a vanishing two-cycle. C1 Los Alamos Natl Lab, Theoret Div T8, Los Alamos, NM 87545 USA. Univ Durham, Dept Phys, Durham DH1 3LE, England. Univ Coll Swansea, Dept Phys, Swansea SA2 8PP, W Glam, Wales. RP Los Alamos Natl Lab, Theoret Div T8, POB 1663, Los Alamos, NM 87545 USA. EM pyth@schwinger.lanl.gov; valya.khoze@durham.ac.uk; mattis@lanl.gov NR 22 TC 9 Z9 9 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 DEC 2 PY 1999 IS 10 AR 019 PG 12 WC Physics, Particles & Fields SC Physics GA 280RV UT WOS:000085116700019 ER PT J AU Friedrich, DM Wang, Z Joly, AG Peterson, KA Callis, PR AF Friedrich, DM Wang, Z Joly, AG Peterson, KA Callis, PR TI Ground-state proton-transfer tautomer of the salicylate anion SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID SOLVENT POLARIZATION DYNAMICS; ENOL-KETO TAUTOMERIZATION; HYDROGEN-ATOM TRANSFER; EXCITED-STATE; ORTHO-HYDROXYBENZALDEHYDE; METHYL SALICYLATE; AQUEOUS-SOLUTION; PHOTOCHEMICAL-REACTIONS; DISUBSTITUTED BENZENES; TRIPLE FLUORESCENCE AB Solutions of sodium salicylate in anhydrous polar solvents exhibit a weak, temperature-dependent absorption band (lambda(max) approximate to 325 nm) lying in the Stakes gap between the main absorption (296 nm) and the fluorescence band (396 nm, acetonitrile). This weak, longer wavelength absorption band is hardly observable in aqueous solution, but its intensity increases with temperature and increases with polarity in anhydrous organic solvents in the order of ethanol < acetonitrile < dimethyl sulfoxide at room temperature. After correction for solvent thermal contraction, the temperature-dependent absorption spectrum of salicylate in acetonitrile solutions reveals a clear isosbestic point (epsilon(310) = 2000 M-1 cm(-1)) characteristic of an equilibrium between two salicylate species with band-maximum extinction coefficients of epsilon(325) = 3400 M-1 cm(-1) and epsilon(296) = 3586 M-1 cm(-1). In acetonitrile at room temperature (298 K) the concentration equilibrium constant (minor/major) for the interconversion reaction between the two species is K-298 = 0.11 With Delta H = 1.6 kcal mol(-1) and Delta S = 0.97 cal.mol(-1) K-1. The fluorescence lifetime (4.8 ns in acetonitrile) and the shape of the fluorescence spectrum are independent of excitation wavelength. The fluorescence quantum yield for excitation in the long-wavelength shoulder (340 nn) is approximately 60% larger than the yield for excitation in the main band at 296 nm (phi(340) = 0.29, phi(296) = 0.18) in acetonitrile at room temperature. These results are consistent with assignment of the shoulder band to the proton-transfer tautomer of the salicylate anion. Electronic structure calculations support assignment of the 325 nm absorption band to the ground-slate tautomer (phenoxide anion form) of the salicylate anion. Absorption transition moments for both the normal and tautomer forms are parallel to the emission transition moment, are electronically allowed, and are consistent with L-1(b) assignment for both absorbing and emitting transitions. The static dipole moments are in the order of mu(N*) greater than or equal to mu(N) > mu(T*) > mu(T) for the normal (N) and tautomer (T) ground and electronic excited states. C1 Pacific NW Lab, Environm & Mol Sci Lab, Richland, WA 99352 USA. Washington State Univ, Dept Chem, Richland, WA 99352 USA. Montana State Univ, Dept Chem, Bozeman, MT 59717 USA. RP Friedrich, DM (reprint author), Opt Coating Lab Inc, 2789 Northpoint Pkwy, Santa Rosa, CA 95407 USA. EM dfriedrich@ocli.com RI Wang, Zheming/E-8244-2010 OI Wang, Zheming/0000-0002-1986-4357 NR 80 TC 20 Z9 20 U1 2 U2 11 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 DEC 2 PY 1999 VL 103 IS 48 BP 9644 EP 9653 DI 10.1021/jp990405+ PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 263EX UT WOS:000084113100011 ER PT J AU Taatjes, CA Christensen, LK Hurley, MD Wallington, TJ AF Taatjes, CA Christensen, LK Hurley, MD Wallington, TJ TI Absolute and site-specific abstraction rate coefficients for reactions of Cl with CH3CH2OH, CH3CD2OH, and CD3CH2OB between 295 and 600 K SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID HYDROGEN-DEUTERIUM ABSTRACTION; CHLORINE ATOMS; TEMPERATURE-DEPENDENCE; BRANCHING RATIO; C2H5O+ ISOMERS; HCL PRODUCTION; BOND-ENERGIES; KINETICS; RADICALS; MECHANISMS AB Absolute rate coefficients for reactions of Cl atoms with selectively deuterated ethanols have been measured between 295 and 600 K by a laser-photolysis/CW infrared absorption method. Yields of HCl are determined by comparison with the Cl + ethane or Cl + propane reaction, permitting site-specific branching fractions to be derived. Smog chamber experiments with Fourier transform infrared (FTIR) detection are performed to determine products of the room-temperature Cl + C2H5OH reaction. The rate coefficients for all ethanols display only a slight temperature dependence and can be parametrized by simple Arrhenius expressions: k(CH3CH2OH) = (9.4 +/- 1.4) x 10(-11)e((45 +/- 32)/T), k(CD3CH2OH) = (6.6 +/- 0.9) x 10(-11)e((90 +/- 40)/T), and k(CH3CD2OH) = (6.9 +/- 0.7) x 10(-11)e((-76 +/- 40)/T) cm(3) molecule(-1) s(-1) (error bars +/-2 sigma). Combining the results from the present work with literature data, we recommend k(CH3CH2OH) = (9.5 +/- 1.9) x 10(-11) cm(3) molecule(-1) s(-1) at 298 K. The room-temperature contribution of abstraction at the methyl site is found to be 0.07 +/- 0.02 from FTIR product analysis of the Cl + CH3CH2OH reaction and 0.08 +/- 0.02 from laser photolysis/CW infrared absorption measurements (error bars +/-2 sigma). Abstraction of the hydroxyl hydrogen is negligible. A small but significant amount of HCl (upsilon = 1) is produced in the Cl + CD3CH2OH and Cl + CH3CH2OH reactions at room temperature. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. Ford Motor Co, Res Staff, Dearborn, MI 48121 USA. RP Taatjes, CA (reprint author), Sandia Natl Labs, Combust Res Facil, Mail Stop 9055, Livermore, CA 94551 USA. NR 44 TC 49 Z9 49 U1 1 U2 11 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 DEC 2 PY 1999 VL 103 IS 48 BP 9805 EP 9814 DI 10.1021/jp992465l PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 263EX UT WOS:000084113100027 ER PT J AU Nicholas, JB Hay, BP AF Nicholas, JB Hay, BP TI Anisole as an ambidentate ligand: Ab initio molecular orbital study of alkali metal cations binding to anisole SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID PI INTERACTIONS; COORDINATION CHEMISTRY; MACROCYCLE INTERACTION; ION SELECTIVITY; KINETIC DATA; COMPLEXES; DESIGN; ETHER; CALIXARENE; ABINITIO AB We present optimized geometries and binding energies for alkali metal cation complexes with anisole (methoxybenzene). Results are obtained for Li+ through Cs+ at the RHF/6-311G* and MP2/6-311+G* levels of theory, with K+, Rb+, and Cs+ represented by relativistic ECPs and associated valence basis sets. RHF/6-311G* frequencies are used to verify that the optimized geometries are minima and to calculate binding enthalpies. The effects of basis set superposition error (BSSE) are estimated at both the RHF and MP2 levels. We find that the alkali metals bind to anisole in two ways, either predominantly through interactions with the aromatic ring or with the ether oxygen. For binding to the ring, we obtain BSSE-corrected MP2/6-311+G* binding enthalpies (in kcal/mol) of -38.1 (Li+), -23.6 (Na+), -18.3 (K+), -15.4 (Rb+), and -13.6 (Cs+). The average distances (in Angstrom) between the ring carbons and the cations are 2.33 (Li+), 2.79 (Na+), 3.20 (K+), 3.44 (Rb+), and 3.70 (Cs+). For binding to the ether oxygen, the BSSE-corrected MP2/6-311G* binding enthalpies (in kcal/mol) are -37.6 (Li+), -25.2 (Na+), -19.4 (K+), -16.4 (Rb+), and -14.3 (Cs+). The distances (in Angstrom) between the ether oxygen and the cations are 1.82 (Li+), 2.24 (Na+), 2.62 (K+), 2.87 (Rb+), and 3.10 (Cs+). Although the differences in binding energy between the two sites are small, the cations generally prefer to bind to the oxygen. C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Nicholas, JB (reprint author), Pacific NW Lab, Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. NR 36 TC 52 Z9 52 U1 0 U2 1 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 DEC 2 PY 1999 VL 103 IS 48 BP 9815 EP 9820 DI 10.1021/jp990570p PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 263EX UT WOS:000084113100028 ER PT J AU Hrbek, J de la Figuera, J Pohl, K Jirsak, T Rodriguez, JA Schmid, AK Bartelt, NC Hwang, RQ AF Hrbek, J de la Figuera, J Pohl, K Jirsak, T Rodriguez, JA Schmid, AK Bartelt, NC Hwang, RQ TI A prelude to surface chemical reaction: Imaging the induction period of sulfur interaction with a strained Cu layer SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Letter ID METAL-METAL INTERFACES; RECONSTRUCTION; FILMS; DISLOCATIONS; MICROSCOPY AB The induction period of the chemical reaction between Cu and S was visualized with STM, revealing a complex interplay between strain relief and reaction mechanism. Copper sulfide formation, monitored by high-resolution soft X-ray photoemission, started only after adsorption of similar to 0.2 ML of S on a two-atom thick Cu layer supported by a Ru(0001) substrate. The pre-sulfide stages of sulfur interaction were investigated by in situ STM. Sulfur decorated the Cu surface by adsorbing at pseudo it-fold hollow sites pf the striped Cu phase and restructured the Cu layer to create additional adsorption sites of this type. Several self-organized structures of adsorbed S on the dynamically responding strained Cu layer were observed. Significant structural changes of both adsorbate and adsorbent occurred within the induction period of this surface chemical reaction. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Sandia Natl Labs, Surface Chem Dept, Livermore, CA 94551 USA. RP Hrbek, J (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RI de la Figuera, Juan/E-7046-2010; Hrbek, Jan/I-1020-2013 OI de la Figuera, Juan/0000-0002-7014-4777; NR 26 TC 23 Z9 23 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 DEC 2 PY 1999 VL 103 IS 48 BP 10557 EP 10561 DI 10.1021/jp992564z PG 5 WC Chemistry, Physical SC Chemistry GA 263EZ UT WOS:000084113300002 ER PT J AU Brozik, JA Scott, BL Swanson, BI AF Brozik, JA Scott, BL Swanson, BI TI Preparation and spectroscopic characterization of [Pt(en)(2)I-2][Pt(CN)(4)]: A new quasi-one-dimensional mixed valence chain material in a completely ordered lattice SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID SUBPICOSECOND DYNAMICS; SOLID PTCL; TRANSITION; EXCITONS; POLARONS AB The unique linear chain compound [Pt(en)(2)I-2][Pt(CN)(4)] {where en = ethylenediamine} has been synthesized through a standard method. The results of a structural analysis by X-ray crystallography reveal this new MX compound to be quasi-one-dimensional with complete chain-to-chain registry to give a completely ordered structure. The results of resonance Raman, IR, diffuse reflectance, and X-ray crystallography reveal that the Pt centers are highly charge disproportionated with a large commensurate distortion of the iodide sublattice about the Pt center of higher charge. These results reveal that this material is the strongest CDW MX compound, containing iodide bridges, reported to date. Resonance Raman experiments have shown that five A(g) (C-2h Site symmetry) Raman bands are strongly enhanced. These correspond to three in-chain Pt-I modes and two (chain perpendicular) CN stretches and are interpreted in terms of strong phonon coupling to the IVCT band. C1 Univ New Mexico, Dept Chem, Albuquerque, NM 87131 USA. Univ Calif Los Alamos Natl Lab, Chem Sch & Technol Div, Los Alamos, NM 87545 USA. RP Brozik, JA (reprint author), Univ New Mexico, Dept Chem, Albuquerque, NM 87131 USA. RI Scott, Brian/D-8995-2017 OI Scott, Brian/0000-0003-0468-5396 NR 18 TC 7 Z9 7 U1 0 U2 2 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 DEC 2 PY 1999 VL 103 IS 48 BP 10566 EP 10571 DI 10.1021/jp990460i PG 6 WC Chemistry, Physical SC Chemistry GA 263EZ UT WOS:000084113300004 ER PT J AU Radyushkin, AV AF Radyushkin, AV TI Skewed parton distributions SO ACTA PHYSICA POLONICA B LA English DT Article; Proceedings Paper CT XXXIXth Cracow School of Theoretical Physics CY MAY 29-JUN 08, 1999 CL ZAKOPANE, POLAND SP Jagellonian Univ, Inst Phys, Polish St Comm Sci Res, Polish Phys Soc ID VIRTUAL COMPTON-SCATTERING; QCD SUM-RULES; HADRONIC FORM-FACTORS; MAGNETIC-MOMENTS; PERTURBATIVE QCD; WAVE-FUNCTIONS; NUCLEON; ELECTROPRODUCTION; MESONS; FACTORIZATION AB Applications of perturbative QCD to deeply virtual Compton scattering and hard exclusive electroproduction processes require a generalization of usual parton distributions for the case when long-distance information is accumulated in nonforward matrix elements of quark and gluon light-cone operators. We describe two types of nonperturbative functions parametrizing such matrix elements: double distributions F(x, y; t) and skewed distribution functions F-zeta(X; t), discuss their properties, and basic uses in the QCD description of hard exclusive processes. C1 Old Dominion Univ, Dept Phys, Norfolk, VA 23529 USA. Jefferson Lab, Newport News, VA 23606 USA. Joint Inst Nucl Res Dubna, Theoret Phys Lab, Dubna, Russia. RP Radyushkin, AV (reprint author), Old Dominion Univ, Dept Phys, Norfolk, VA 23529 USA. NR 49 TC 5 Z9 5 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 DEC PY 1999 VL 30 IS 12 BP 3647 EP 3678 PG 32 WC Physics, Multidisciplinary SC Physics GA 277UT UT WOS:000084952500008 ER PT J AU McLerran, L AF McLerran, L TI Two lectures on small x and high gluon density SO ACTA PHYSICA POLONICA B LA English DT Article; Proceedings Paper CT XXXIXth Cracow School of Theoretical Physics CY MAY 29-JUN 08, 1999 CL ZAKOPANE, POLAND SP Jagellonian Univ, Inst Phys, Polish St Comm Sci Res, Polish Phys Soc ID COLLISIONS; NUCLEUS; FIELD AB In these lectures, I shall discuss small x physics and the consequences of the high gluon density which arises as x decreases. I argue that an understanding of this problem would lead to knowledge of the high energy asymptotics of hadronic processes. The high gluon density should allow a first principles computation of these asymptotics from QCD. This physics might be experimentally probed in heavy ion colliders or in high energy electron-nuclear collisions. C1 Brookhaven Natl Lab, Nucl Theory Grp, Upton, NY 11973 USA. RP McLerran, L (reprint author), Brookhaven Natl Lab, Nucl Theory Grp, Upton, NY 11973 USA. NR 17 TC 7 Z9 7 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 DEC PY 1999 VL 30 IS 12 BP 3707 EP 3729 PG 23 WC Physics, Multidisciplinary SC Physics GA 277UT UT WOS:000084952500010 ER PT J AU Venugopalan, R AF Venugopalan, R TI Classical methods in DIS and nuclear scattering at small x SO ACTA PHYSICA POLONICA B LA English DT Article; Proceedings Paper CT XXXIXth Cracow School of Theoretical Physics CY MAY 29-JUN 08, 1999 CL ZAKOPANE, POLAND SP Jagellonian Univ, Inst Phys, Polish St Comm Sci Res, Polish Phys Soc ID GLUON DISTRIBUTION-FUNCTIONS; DEEP-INELASTIC-SCATTERING; WEIZSACKER-WILLIAMS FIELD; HEAVY-ION COLLISIONS; HIGH-ENERGY; PARTON DISTRIBUTIONS; TRANSVERSE-MOMENTUM; QCD; MODEL; DENSITIES AB In hadrons and nuclei at very small x, parton distributions saturate at a scale Q(s)(x). Since the occupation number is large, and Q(s)(x) much greater than Lambda(QCD), classical weak coupling methods may be used to study this novel regime of non-linear classical fields in QCD. In these lectures, we apply these methods to compute structure functions in deeply inelastic scattering (DIS) and the energy density of gluons produced in high energy nuclear collisions. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 75 TC 61 Z9 61 U1 0 U2 0 PU JAGIELLONIAN UNIV PRESS PI KRAKOW PA UL MICHALOWSKIEGO 9-2, KRAKOW, 31126, POLAND SN 0587-4254 EI 1509-5770 J9 ACTA PHYS POL B JI Acta Phys. Pol. B PD DEC PY 1999 VL 30 IS 12 BP 3731 EP 3761 PG 31 WC Physics, Multidisciplinary SC Physics GA 277UT UT WOS:000084952500011 ER PT J AU Czarnecki, A AF Czarnecki, A TI Positronium properties SO ACTA PHYSICA POLONICA B LA English DT Article; Proceedings Paper CT XXXIXth Cracow School of Theoretical Physics CY MAY 29-JUN 08, 1999 CL ZAKOPANE, POLAND SP Jagellonian Univ, Inst Phys, Polish St Comm Sci Res, Polish Phys Soc ID ORTHOPOSITRONIUM DECAY-RATE; PRECISION-MEASUREMENT; ORDER M-ALPHA(6); GROUND-STATE; SEARCH AB This talk gives an elementary introduction to the basic properties of positronium. Recent progress in theoretical studies of the hyperfine splitting and lifetime of the ground state is reviewed. Sensitivity of these precisely measured quantities to some New Physics effects is discussed. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Czarnecki, A (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 26 TC 3 Z9 4 U1 2 U2 4 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 DEC PY 1999 VL 30 IS 12 BP 3837 EP 3847 PG 11 WC Physics, Multidisciplinary SC Physics GA 277UT UT WOS:000084952500015 ER PT J AU Dziarmaga, J AF Dziarmaga, J TI Topological defects from an inhomogeneous quench: Second and first order transitions SO ACTA PHYSICA POLONICA B LA English DT Article; Proceedings Paper CT XXXIXth Cracow School of Theoretical Physics CY MAY 29-JUN 08, 1999 CL ZAKOPANE, POLAND SP Jagellonian Univ, Inst Phys, Polish St Comm Sci Res, Polish Phys Soc ID COSMOLOGICAL EXPERIMENTS; VORTEX FORMATION; SUPERFLUID HE-3; SYMMETRY BREAKS; COSMIC STRINGS; ANALOG; PIECES; HELIUM; BIG AB Kibble-Zurek scenario of topological defects formation is extended to inhomogeneous first and second order transitions. In both cases there is characteristic threshold velocity of critical front propagation below which no topological defects are produced. Instead oriented condensate is grown behind moving temperature or pressure front. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Jagiellonian Univ, Inst Phys, PL-30059 Krakow, Poland. RP Dziarmaga, J (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 22 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 DEC PY 1999 VL 30 IS 12 BP 3909 EP 3919 PG 11 WC Physics, Multidisciplinary SC Physics GA 277UT UT WOS:000084952500020 ER PT J AU Martin, MZ Cheng, MD Martin, RC AF Martin, MZ Cheng, MD Martin, RC TI Aerosol measurement by laser-induced plasma technique: A review SO AEROSOL SCIENCE AND TECHNOLOGY LA English DT Review ID INDUCED BREAKDOWN SPECTROSCOPY; INDUCTIVELY COUPLED PLASMA; INDUCED AIR BREAKDOWN; SPECTROCHEMICAL ANALYSIS; WAVELENGTH DEPENDENCE; EMISSION SPECTROMETRY; METAL EMISSIONS; FLUORESCENCE; LIQUIDS; SAMPLES AB Literature on laser-induced plasma spectroscopy (LIPS) published since the 1960s is reviewed and presented in this report, although LIPS of solid samples has been emphasized in the past. The LIPS is found to be the most convenient technique for in-situ and real-time measurement of metal species in the gaseous and aerosol phases, This technique is a strong candidate for the development of a next-generation field portable instrument for characterizing metal species from the emission sources as well as ambient environments, The instrument can provide a highly resolved spatial and temporal data of significance to environmental and health research on metal and particle toxicity, an instrument based on LIPS can be a viable tool for continuously monitoring toxic metal emissions at an industrial source, for example, The wide range of lasers used and other experimental anti theoretical factors to be considered in the design of a LIPS instrument for aerosol measurements was discussed in this report. Experimental results from different studies on the high-energy laser interaction with aerosols and breakdown thresholds as a function of particle size, particle density, and wavelength are presented and the physical processes are discussed. Although it is not meant to be an exhaustive survey, this review serves as the basis for our ongoing development of a miniaturized LIPS-based instrument at the Oak Ridge National Laboratory. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Oak Ridge Inst Sci & Technol, Oak Ridge, TN USA. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN USA. RP Cheng, MD (reprint author), Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RI Martin, Madhavi/A-5268-2011; Cheng, Meng-Dawn/C-1098-2012; OI Martin, Madhavi/0000-0002-6677-2180; Cheng, Meng-Dawn/0000-0003-1407-9576 NR 56 TC 39 Z9 40 U1 0 U2 14 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 DEC PY 1999 VL 31 IS 6 BP 409 EP 421 DI 10.1080/027868299303968 PG 13 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 259GR UT WOS:000083886600001 ER PT J AU Schilling, CH Gray, JN AF Schilling, CH Gray, JN TI NDE: Needs, opportunities in ceramic processing SO AMERICAN CERAMIC SOCIETY BULLETIN LA English DT Article AB A new generation of process development tools is needed to provide a better fundamental understanding of defect evolution during processing, tools that involve the combined use of manufacturing process simulations and NDE. C1 Iowa State Univ, Dept Mat Sci & Engn, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Ctr Nondestruct Evaluat, Ames, IA 50011 USA. Iowa State Univ, Dept Mech Engn, Ames, IA 50011 USA. RP Schilling, CH (reprint author), Iowa State Univ, Dept Mat Sci & Engn, Ames Lab, Ames, IA 50011 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7812 J9 AM CERAM SOC BULL JI Am. Ceram. Soc. Bull. PD DEC PY 1999 VL 78 IS 12 BP 74 EP 80 PG 7 WC Materials Science, Ceramics SC Materials Science GA 291WU UT WOS:000085763000008 ER PT J AU Williams, PT Krauss, RM AF Williams, PT Krauss, RM TI Low-fat diets, lipoprotein subclasses, and heart disease risk SO AMERICAN JOURNAL OF CLINICAL NUTRITION LA English DT Editorial Material ID PATTERNS; MEN C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Dept Mol Med, Div Life Sc,Donner Lab, Berkeley, CA 94720 USA. RP Krauss, RM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Dept Mol & Nucl Med, Div Life Sci,Donner Lab, Room 459,1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 10 TC 7 Z9 7 U1 0 U2 0 PU AMER SOC CLINICAL NUTRITION PI BETHESDA PA 9650 ROCKVILLE PIKE, SUBSCRIPTIONS, RM L-3300, BETHESDA, MD 20814-3998 USA SN 0002-9165 J9 AM J CLIN NUTR JI Am. J. Clin. Nutr. PD DEC PY 1999 VL 70 IS 6 BP 949 EP 950 PG 2 WC Nutrition & Dietetics SC Nutrition & Dietetics GA 360VV UT WOS:000089688800001 PM 10584036 ER PT J AU Vidal, R Goni, F Stevens, F Aucouturier, P Kumar, A Frangione, B Ghiso, J Gallo, G AF Vidal, R Goni, F Stevens, F Aucouturier, P Kumar, A Frangione, B Ghiso, J Gallo, G TI Somatic mutations of the l12a gene in V-kappa(1) light chain deposition disease - Potential effects on aberrant protein conformation and deposition SO AMERICAN JOURNAL OF PATHOLOGY LA English DT Article ID GLOMERULAR BASEMENT-MEMBRANE; MONOCLONAL KAPPA-CHAIN; AMINO-ACID-SEQUENCE; AMYLOIDOSIS; SUBGROUP; IDENTITY; PATIENT; MYELOMA AB Light chain deposition disease (LCDD) and light chain amyloidosis (AL) are disorders of monoclonal immunoglobulin deposition in which normally soluble serum precursors form insoluble deposits in tissues. A common feature in both is the clonal proliferation of B-cells that produce pathogenic light chains. However, the deposits in LCDD differ from those in AL in that they are ultrastructurally granular rather than fibrillar and do not bind Congo red or colocalize with amyloid P component or apolipoprotein E. The reason(s) for their differences are unknown but are likely multifactorial and related to their protein conformation and their interaction with other molecules and tissue factors in the microenvironment. Knowledge of the primary structure of the light chains in LCDD is very limited. In the present study two new kappa(1) light chains from patients with LCDD are described and compared to seven other reported kappa-LCDD proteins. The N-terminal amino acid sequences of light chain GLA extracted from the renal biopsy and light chain CHO from myocardial tissue were each identical to the respective light chains isolated from the urines and to the V-region amino acid sequences translated from the cloned cDNAs obtained from bone marrow cells. The germline V-region sequences, determined from the genomic DNA in both and in MCM, a previously reported kappa(1) LCDD Light chain, were identical and related to the L12a germline gene. The expressed Light chains in all three exhibit amino acid substitutions that arise from somatic mutation and result in increased hydrophobicity with the potential for protein destabilization and disordered conformation. C1 NYU Med Ctr, Sch Med, Dept Pathol, New York, NY 10016 USA. Univ Republ Oriental Uruguay, Fac Quim, Montevideo, Uruguay. Argonne Natl Lab, Biosci Div, Argonne, IL 60439 USA. RP Gallo, G (reprint author), NYU Med Ctr, Sch Med, Dept Pathol, 560 1st Ave, New York, NY 10016 USA. FU NIAMS NIH HHS [R01 AR002594, AR 02594]; NIDDK NIH HHS [DKY 3757] NR 39 TC 31 Z9 35 U1 0 U2 2 PU AMER SOC INVESTIGATIVE PATHOLOGY, INC PI BALTIMORE PA 428 EAST PRESTON ST, BALTIMORE, MD 21202-3993 USA SN 0002-9440 J9 AM J PATHOL JI Am. J. Pathol. PD DEC PY 1999 VL 155 IS 6 BP 2009 EP 2017 DI 10.1016/S0002-9440(10)65520-4 PG 9 WC Pathology SC Pathology GA 262XD UT WOS:000084092800027 PM 10595931 ER PT J AU Lemons, DS Lund, CM AF Lemons, DS Lund, CM TI Thermodynamics of high temperature, Mie-Gruneisen solids SO AMERICAN JOURNAL OF PHYSICS LA English DT Article AB We construct a set of equations of state for condensed matter at temperatures well above the Debye temperature. These equations incorporate the Mie-Gruneisen equation of state and generic properties of high temperature solids. They are simple enough to provide an alternative to the ideal gas and the van der Waals equations of state for illustrating thermodynamic concepts. (C) 1999 American Association of Physics Teachers. C1 Bethel Coll, N Newton, KS 67117 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Lemons, DS (reprint author), Bethel Coll, N Newton, KS 67117 USA. NR 13 TC 10 Z9 10 U1 0 U2 1 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 DEC PY 1999 VL 67 IS 12 BP 1105 EP 1108 DI 10.1119/1.19091 PG 4 WC Education, Scientific Disciplines; Physics, Multidisciplinary SC Education & Educational Research; Physics GA 261RW UT WOS:000084023600012 ER PT J AU Luban, M Luscombe, JH AF Luban, M Luscombe, JH TI Equilibrium time correlation functions and the dynamics of fluctuations SO AMERICAN JOURNAL OF PHYSICS LA English DT Article ID DIFFUSION AB Equilibrium time correlation functions are of great importance because they probe the equilibrium dynamical response to external perturbations. We discuss the properties of time correlation functions for several systems that are simple enough to illustrate the calculational steps involved. The discussion underscores the need for avoiding language which misleadingly suggests that thermal equilibrium is associated with a quiescent or moribund state of the system. (C) 1999 American Association of Physics Teachers. C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames, IA 50011 USA. USN, Postgrad Sch, Dept Phys, Monterey, CA 93943 USA. RP Luban, M (reprint author), Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. NR 37 TC 8 Z9 8 U1 1 U2 5 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 DEC PY 1999 VL 67 IS 12 BP 1161 EP 1169 DI 10.1119/1.19102 PG 9 WC Education, Scientific Disciplines; Physics, Multidisciplinary SC Education & Educational Research; Physics GA 261RW UT WOS:000084023600023 ER PT J AU Van Berkel, GJ Giles, GE Bullock, JS Gray, LJ AF Van Berkel, GJ Giles, GE Bullock, JS Gray, LJ TI Computational simulation of redox reactions within a metal electrospray emitter SO ANALYTICAL CHEMISTRY LA English DT Article ID IONIZATION MASS-SPECTROMETRY; CURRENT ELECTROLYTIC PROCESS; ION-SOURCE; CELL; MECHANISM; ANALYTES; INHERENT AB A computational simulation of the oxidation of chemical species inside a metal emitter electrospray ion source, in the context of electrospray mass spectrometry (ES-MS), has been developed. The analysis code employs a boundary integral method for the solution of the Laplace equation for the electric potential and current and incorporates standard activation and concentration polarization functions for the redox-active species in the system to define the boundary conditions. This paper provides a demonstration of the capability of this simulation method. Due to the approximate nature of some of the input data, and certain simplifying assumptions, the present results must be considered semiquantitative, The specific system modeled consisted of a 100-mu m-i.d., inert metal capillary ES emitter and a spray solution composed of an analyte dissolved in CH(3)CN/H(2)O (90/10 v/v), Variable parameters included the concentration (i.e., 5.0, 10, 20, and 50 mu M) of the easily oxidized analyte ferrocene (Fc, dicyclopentadienyl iron) in the solution, and solution conductivities of 1.9, 3.8, and 7.6 x 10(-7) Omega(-1)/cm, with an operational flow rate of 5.0 mu L/min and ES currents on the order of 0.05 mu A. Under these defined conditions, the two most prominent reactions at the emitter metal/ solution interface were assumed to be H(2)O oxidation (2H(2)O = O(2) + 4H(+-) + 4e(-)) and ferrocene oxidation (Fc Fc(+) + e(-)). Using this model, it was possible to predict the interfacial potentials, as well as the current density for each of the reactions, as a function of axial position from the emitter spray tip back upstream, under the various operational conditions. The simulations show that the majority of the current from the redox reactions is generated within a 200-300-mu m region near the spray tip. The lower the value of E(0) for a specific reaction, the further upstream from the tip the reaction extends. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Computat Phys & Engn Div, Oak Ridge, TN 37831 USA. Oak Ridge Y-12 Plant, Dev Div, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Math & Comp Sci, Oak Ridge, TN 37831 USA. RP Van Berkel, GJ (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. EM vanberkelgj@ornl.gov; geg@ornl.gov; jsb@ornl.gov NR 34 TC 46 Z9 46 U1 1 U2 7 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 DEC 1 PY 1999 VL 71 IS 23 BP 5288 EP 5296 DI 10.1021/ac9905266 PG 9 WC Chemistry, Analytical SC Chemistry GA 260YW UT WOS:000083981900012 PM 21662726 ER PT J AU Shen, YF Xiang, F Veenstra, TD Fung, EN Smith, RD AF Shen, YF Xiang, F Veenstra, TD Fung, EN Smith, RD TI High-resolution capillary isoelectric focusing of complex protein mixtures from lysates of microorganisms SO ANALYTICAL CHEMISTRY LA English DT Article AB High-resolution capillary isoelectric focusing separations of complex protein mixtures have been obtained for cellular lysates of Saccharomyces cerevisiae, Eschericia coli, and Deinococcus radiodurans, High quality separations are shown to be achievable for total protein concentrations of <0.1 mg/mL. The separation reproducibility was examined, and the influence of the capillary inner wall coating on resolution investigated using fused-silica capillaries coated with various hydrophilic polymers including hydroxypropyl cellulose, poly(vinyl alcohol), and linear polyacrylamide. Proteins having an isoelectric point (pI) difference of 0.004 are shown to be separated using a linear carrier ampholyte (linear pH gradient between two electrodes) of 3-10. Approximately 45 discrete peaks in the pi range of 5-7 were obtained for S. cereuisiae, similar to 80 peaks in the pi range of 4.5-8.5 for E. coli, and similar to 210 peaks in the pi range of 3-8.8 for D. radiodurans. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Pacific NW Natl Lab, Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. RI Smith, Richard/J-3664-2012 OI Smith, Richard/0000-0002-2381-2349 NR 13 TC 65 Z9 67 U1 0 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 EI 1520-6882 J9 ANAL CHEM JI Anal. Chem. PD DEC 1 PY 1999 VL 71 IS 23 BP 5348 EP 5353 DI 10.1021/ac9909305 PG 6 WC Chemistry, Analytical SC Chemistry GA 260YW UT WOS:000083981900021 PM 10596214 ER PT J AU Egorov, OB Fiskum, SK O'Hara, MJ Grate, JW AF Egorov, OB Fiskum, SK O'Hara, MJ Grate, JW TI Radionuclide sensors based on chemically selective scintillating microspheres: Renewable column sensor for analysis of Tc-99 in water SO ANALYTICAL CHEMISTRY LA English DT Article ID SOLID-PHASE EXTRACTION; SEQUENTIAL INJECTION; NUCLEAR WASTE; AUTOMATED-ANALYSIS; ACIDIC MEDIA; FLOW-CELL; SEPARATION; PRECONCENTRATION; ACTINIDES; SYSTEM AB A method for chemically selective radiometric sensing of non-gamma-emitting radionuclides in solution is described. Using scintillating microspheres with selective radionuclide uptake properties, radiochemical separation and radiometric detection steps are integrated within a sensor device. These microspheres are loaded into a renewable minicolumn that serves to capture, preconcentrate, and separate radionuclides. The preconcentrating minicolumn also localizes and retains radionuclides within a detector of well-defined geometry and emits a photometric signal. The sensor material in the column can either be regenerated with eluent chemistries or be renewed by fluidic replacement of the beads. The latter method allows the use of materials that bind analytes irreversibly or are unstable under regeneration conditions. Radionuclide-selective scintillating microspheres were prepared by coimmobilization of scintillating fluors and selective organic extractants within the pores of an inert polymeric support. Preparation and characterization of microspheres, and their use for selective quantitative sensing of Tc-99(VII), is described in detail. A sensor-based procedure for Tc-99(VII) analysis was developed and successfully applied toward the determination of Tc-99(VII) in groundwater samples from the Hanford site, using standard addition techniques for quantification, Using a 50-mL sample volume and signal accumulation time of 30 min, the detection limit for Tc-99(VII) was 0.37 dpm/mL (9.8 pg/mL). C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Pacific NW Natl Lab, Appl Geol & Geochem Grp, Richland, WA 99352 USA. Pacific NW Natl Lab, Radiochem Proc Lab, Richland, WA 99352 USA. RP Grate, JW (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. RI O'Hara, Matthew/I-4967-2013; OI O'Hara, Matthew/0000-0003-3982-5897 NR 52 TC 41 Z9 41 U1 0 U2 9 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 DEC 1 PY 1999 VL 71 IS 23 BP 5420 EP 5429 DI 10.1021/ac990735q PG 10 WC Chemistry, Analytical SC Chemistry GA 260YW UT WOS:000083981900032 PM 21662739 ER PT J AU Nakamura, R Haerendel, G Baumjohann, W Vaivads, A Kucharek, H Klecker, B Georgescu, E Birn, J Kistler, LM Mukai, T Kokubun, S Eglitis, P Frank, LA Sigwarth, JB AF Nakamura, R Haerendel, G Baumjohann, W Vaivads, A Kucharek, H Klecker, B Georgescu, E Birn, J Kistler, LM Mukai, T Kokubun, S Eglitis, P Frank, LA Sigwarth, JB TI Substorm observations in the early morning sector with Equator-S and Geotail SO ANNALES GEOPHYSICAE-ATMOSPHERES HYDROSPHERES AND SPACE SCIENCES LA English DT Article DE magnetospheric physics (magnetospheric; configuration and dynamics; plasma sheet; storms and substorms) ID PLASMA SHEET; MAGNETOTAIL; INJECTIONS; SATELLITE; ONSET; ORBIT; MODEL AB Data from Equator-S and Geotail are used to study the dynamics of the plasma sheet observed during a substorm with multiple intensifications on 25 April 1998, when both spacecraft were located in the early morning sector (03-04 MLT) at a radial distance of 10-11 RE In association with the onset of a poleward expansion of the aurora and the westward electrojet in the premidnight and midnight sector, both satellites in the morning sector observed plasma sheet thinning and changes toward a more tail-like field configuration. During the subsequent poleward expansion in a wider local time sector (20-04 MLT), on the other hand, the magnetic field configuration at both satellites changed into a more dipolar configuration and both satellites encountered again the hot plasma sheet. High-speed plasma flows with velocities of up to 600 km/s and lasting 2-5 min were observed in the plasma sheet and near its boundary during this plasma sheet expansion. These high-speed flows included significant dawn-dusk flows and had a shear structure. They may have been produced by an induced electric field at the local dipolarization region and/or by an enhanced pressure gradient associated with the injection in the midnight plasma sheet. C1 Max Planck Inst Extraterr Phys, D-37075 Garching, Germany. Inst Space Sci, Bucharest, Romania. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA. Inst Space & Astronaut Sci, Sagamihara, Kanagawa 229, Japan. Nagoya Univ, Solar Terr Environm Lab, Nagoya, Aichi, Japan. Swedish Inst Space Phys, Uppsala, Sweden. Finnish Meteorol Inst, FIN-00101 Helsinki, Finland. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. RP Nakamura, R (reprint author), Max Planck Inst Extraterr Phys, D-37075 Garching, Germany. EM rumi@mpe.mpg.de RI Baumjohann, Wolfgang/A-1012-2010; Nakamura, Rumi/I-7712-2013; OI Baumjohann, Wolfgang/0000-0001-6271-0110; Nakamura, Rumi/0000-0002-2620-9211; Vaivads, Andris/0000-0003-1654-841X NR 24 TC 7 Z9 7 U1 0 U2 2 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0992-7689 J9 ANN GEOPHYS-ATM HYDR JI Ann. Geophys.-Atmos. Hydrospheres Space Sci. PD DEC PY 1999 VL 17 IS 12 BP 1602 EP 1610 DI 10.1007/s00585-999-1602-3 PG 9 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA 272CX UT WOS:000084633900011 ER PT J AU Takai, K Horikoshi, K AF Takai, K Horikoshi, K TI Molecular phylogenetic analysis of archaeal intron-containing genes coding for rRNA obtained from a deep-subsurface geothermal water pool SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID RIBOSOMAL-RNA GENE; SP-NOV; REDUCING BACTERIUM; SEQUENCES; DIVERSITY; BIOSPHERE; RESERVOIR; SEA AB Molecular phylogenetic analysis of a naturally occurring microbial community in a deep-subsurface geothermal environment indicated that the phylogenetic diversity of the microbial population in the environment was extremely limited and that only hyperthermophilic archaeal members closely related to Pyrobaculum were present. All archaeal ribosomal DNA sequences contained intron-like sequences, some of which had open reading frames with repeated homing-endonuclease motifs. The sequence similarity analysis and the phylogenetic analysis of these homing endonucleases suggested the possible phylogenetic relationship among archaeal rRNA-encoded homing endonucleases. C1 Japan Marine Sci & Technol Ctr, Deep Sea Microorganisms Res Grp, Yokosuka, Kanagawa 2370061, Japan. RP Takai, K (reprint author), Pacific NW Lab, POB 999,Mail Stop P7-50, Richland, WA 99352 USA. EM Ken.Takai@pnl.gov NR 34 TC 29 Z9 31 U1 0 U2 1 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD DEC PY 1999 VL 65 IS 12 BP 5586 EP 5589 PG 4 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 261XV UT WOS:000084036800058 PM 10584021 ER PT J AU Kim, BM Eichler, J Da Silva, LB AF Kim, BM Eichler, J Da Silva, LB TI Frequency doubling of ultrashort laser pulses in biological tissues SO APPLIED OPTICS LA English DT Article ID 2ND-HARMONIC GENERATION; 3RD-HARMONIC GENERATION; MICROSCOPY AB Theoretical and experimental studies of second-harmonic generation (SHG) in biological tissues was performed by use of ultrashort laser pulses (<1 ps). A simplified one-dimensional model for the generation and the propagation of frequency-doubled light inside tissue was developed. This model was tested in vitro against measurements of pig and chicken tissue and human tooth. The experimental results indicate that the intensity of SHG varies significantly among tissue types and between test sites in individual tissue. Possibilities of using this nonlinear tissue property in imaging and diagnostics are discussed. (C) 1999 Optical Society of America. OCIS codes: 140.7090, 170.6930, 190.4160, 190.7110. C1 Lawrence Livermore Natl Lab, Med Technol Program, Livermore, CA 94550 USA. Univ Appl Sci, Tech Fachhsch Berlin, D-13347 Berlin, Germany. RP Kim, BM (reprint author), Lawrence Livermore Natl Lab, Med Technol Program, 7000 E Ave L-399, Livermore, CA 94550 USA. EM kim12@llnl.gov NR 24 TC 40 Z9 42 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 DEC 1 PY 1999 VL 38 IS 34 BP 7145 EP 7150 DI 10.1364/AO.38.007145 PG 6 WC Optics SC Optics GA 261RV UT WOS:000084023500021 PM 18324261 ER PT J AU Banks, PS Feit, MD Rubenchik, AM Stuart, BC Perry, MD AF Banks, PS Feit, MD Rubenchik, AM Stuart, BC Perry, MD TI Material effects in ultra-short pulse laser drilling of metals SO APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING LA English DT Article; Proceedings Paper CT 5th International Conference on Laser Ablation COLA'99 CY JUL 19-23, 1999 CL GOTTINGEN, GERMANY ID FEMTOSECOND; PICOSECOND; ABLATION AB Although hole drilling using ultra-short laser pulses has been shown to produce holes of excellent quality, we have observed that during the evolution of the hole, the morphology of the hole bottom has a dependence on fluence, number of shots, and polarization. We describe the nature of this structure within the hole and under what conditions it is observed. C1 Univ Calif Lawrence Livermore Natl Lab, Laser Program, Livermore, CA 94550 USA. RP Banks, PS (reprint author), Univ Calif Lawrence Livermore Natl Lab, Laser Program, POB 808,L-477, Livermore, CA 94550 USA. RI Feit, Michael/A-4480-2009; Stuart, Brent/K-4988-2015 NR 9 TC 29 Z9 30 U1 1 U2 12 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0947-8396 J9 APPL PHYS A-MATER JI Appl. Phys. A-Mater. Sci. Process. PD DEC PY 1999 VL 69 SU S BP S377 EP S380 DI 10.1007/s003390051420 PG 4 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 287WV UT WOS:000085530400076 ER PT J AU Banks, PS Dinh, L Stuart, BC Feit, MD Komashko, AM Rubenchik, AM Perry, MD McLean, W AF Banks, PS Dinh, L Stuart, BC Feit, MD Komashko, AM Rubenchik, AM Perry, MD McLean, W TI Short-pulse laser deposition of diamond-like carbon thin films SO APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING LA English DT Article; Proceedings Paper CT 5th International Conference on Laser Ablation COLA'99 CY JUL 19-23, 1999 CL GOTTINGEN, GERMANY ID ABLATION; ENERGY AB The high intensities present in and the non-thermal nature of ultrashort-pulse laser ablation provide a nearly ideal source for thin-film deposition. The high kinetic energies and high ion content in the ablation plume suggest that it would be useful for the creation of diamond thin films. We used a 120 fs, 3 W, 1 kHz laser to ablate a graphite target and characterized the resulting films. We were able to grow amorphous films of up to 18 mu m thick and free from graphite particulates with no annealing necessary and at rates up to 25 mu m/hr. The films had 40%-50% sp(3) bonds as measured by using EELS and had properties typical of PLD-generated diamond-like carbon films. C1 Univ Calif Lawrence Livermore Natl Lab, Laser Program, Livermore, CA 94550 USA. RP Banks, PS (reprint author), Univ Calif Lawrence Livermore Natl Lab, Laser Program, POB 808,L-477, Livermore, CA 94550 USA. RI Feit, Michael/A-4480-2009; Stuart, Brent/K-4988-2015 NR 14 TC 30 Z9 32 U1 0 U2 3 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0947-8396 J9 APPL PHYS A-MATER JI Appl. Phys. A-Mater. Sci. Process. PD DEC PY 1999 VL 69 SU S BP S347 EP S353 DI 10.1007/s003390051415 PG 7 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 287WV UT WOS:000085530400071 ER PT J AU Dawes, ML Hess, W Kawaguchi, Y Langford, SC Dickinson, JT AF Dawes, ML Hess, W Kawaguchi, Y Langford, SC Dickinson, JT TI Laser-induced positive ion and neutral atom/molecule emission from single-crystal CaHPO4 center dot 2 H2O: The role of electron-beam-induced defects SO APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING LA English DT Article; Proceedings Paper CT 5th International Conference on Laser Ablation COLA'99 CY JUL 19-23, 1999 CL GOTTINGEN, GERMANY ID EFFLORESCENCE; SURFACES; MGO AB We examine laser-induced ion and neutral emissions from single-crystal CaHPO4 . 2H(2)O (brushite), a wideband-gap, hydrated inorganic single crystal, with 248-nm excimer laser radiation. Both laser-induced ion and neutral emissions are several orders of magnitude higher following exposure to 2 keV electrons at current densities of 200 mu A/cm(2) and doses of 1 C/cm(2). In addition to intense Ca+ signals, electron-irradiated surfaces yield substantial CaO+, PO+, and pf signals. As-grown and as-cleaved brushite show only weak neutral O-2 and Ca emissions, whereas electron-irradiated surfaces yield enhanced O-2, Ca, PO, PO2, and P emissions. Electron irradiation (i) significantly heats the sample, leading to thermal dehydration (CaHPO4 formation) and pyrolysis (Ca2P2O7 formation) and (ii) chemically reduces the surface via electron stimulated desorption. The thermal effects are accompanied by morphological changes, including recrystallization. Although complex, these changes lead to high defect densities, which are responsible for the dramatic enhancements in the observed laser desorption. C1 Washington State Univ, Surface Dynam Lab, Dept Phys, Pullman, WA 99164 USA. Pacific NW Lab, William R Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Kawaguchi, Y (reprint author), Washington State Univ, Surface Dynam Lab, Dept Phys, Pullman, WA 99164 USA. RI Kawaguchi, Yoshizo/K-9353-2016 OI Kawaguchi, Yoshizo/0000-0002-9509-8316 NR 14 TC 4 Z9 4 U1 0 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0947-8396 J9 APPL PHYS A-MATER JI Appl. Phys. A-Mater. Sci. Process. PD DEC PY 1999 VL 69 SU S BP S547 EP S552 DI 10.1007/s003390051468 PG 6 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 287WV UT WOS:000085530400115 ER PT J AU Hess, WP Joly, AG Beck, KM Williams, RM Dickinson, JT AF Hess, WP Joly, AG Beck, KM Williams, RM Dickinson, JT TI Femtosecond time-resolved laser-induced desorption of positive ions from MgO SO APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING LA English DT Article; Proceedings Paper CT 5th International Conference on Laser Ablation COLA'99 CY JUL 19-23, 1999 CL GOTTINGEN, GERMANY ID ELECTRON-HOLE PAIRS; SURFACE; CRYSTALS; EXCITATION; RELAXATION; RADIATION; EMISSION; DYNAMICS; EXCITONS; BULK AB We have used the pump-probe technique to measure the photostimulated positive ion yield as a funct:ion of time delay between two sub-threshold femtosecond laser pulses. We find that the ion yield from UV femtosecond irradiated MgO depends critically on the laser pulse delay, Delta t, in two-pulse experiments. In single-pulse experiments, excitation of MgO produces a variety of ions including Mg+, MgO+, and a significant yield of H+. In contrast, if the femtosecond laser pulse is split into two sub-threshold beams and then recombined with a variable time delay, the ion yield may be drastically altered depending on the delay between pulses. The Mg+ desorption yield displays three distinct lifetimes and persists for laser delays of over 100 ps. A pulse delay of only Delta t = 500 fs nearly eliminates ion desorption except for Mg+. The use of a pair of delayed femtosecond laser pulses can thus control the species of the desorbed ion. The mechanism for femtosecond laser desorption is clearly different from nanosecond laser desorption. We hypothesize that the creation of electron-hole pairs by nonresonant two-photon excitation contributes to the ultrafast desorption mechanism. C1 Pacific NW Lab, Richland, WA 99352 USA. Washington State Univ, Dept Phys, Pullman, WA 99164 USA. RP Hess, WP (reprint author), Pacific NW Lab, POB 999, Richland, WA 99352 USA. NR 33 TC 10 Z9 10 U1 0 U2 4 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0947-8396 J9 APPL PHYS A-MATER JI Appl. Phys. A-Mater. Sci. Process. PD DEC PY 1999 VL 69 SU S BP S389 EP S393 DI 10.1007/s003390051423 PG 5 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 287WV UT WOS:000085530400079 ER PT J AU Joly, AG Beck, KM Hess, WP AF Joly, AG Beck, KM Hess, WP TI Ultrafast and nanosecond laser-induced desorption of positive ions from lithium fluoride single crystals SO APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING LA English DT Article; Proceedings Paper CT 5th International Conference on Laser Ablation COLA'99 CY JUL 19-23, 1999 CL GOTTINGEN, GERMANY ID ELECTRON-STIMULATED DESORPTION; ALKALI-HALIDE CRYSTALS; GROUND-STATE; EXCITED ATOMS; AUGER DECAY; METAL ATOMS; BOMBARDMENT; EXCITATION; DEPENDENCE; EMISSION AB We compare desorption of positive ions from lithium fluoride single crystals following pulsed laser excitation using either femtosecond (180 fs, 265 nm) or nanosecond (3 ns, 266 nm) sources. Following optical excitation, desorbed ions are mass analyzed using standard time-of-flight techniques. Several important differences between nanosecond and femtosecond excitation are revealed. Femtosecond excitation produces higher kinetic energy Li+ than does nanosecond excitation (10 eV vs. 5 eV) while nanosecond excitation yields significant quantities of impurity ions Na+ and K+, in addition to efficient Li+ emission. The Li+ desorption threshold is similar for both, laser sources. This similarity is a surprising result, as sub-bandgap nanosecond pulses are only likely to excite defect states efficiently (via linear excitation), while the ultrahigh peak-power femtosecond pulses could in principle induce multiphoton and avalanche excitation. Femtosecond excitation results in much less complicated time-of-flight spectra, as predominantly Li+ is detected with some H+ also observed. We have measured the Li+ yield as a function of time delay between two sub-threshold femtosecond laser pulses. We find that the majority of the Li+ yield decays rapidly, largely within the fs pulse duration. However, a weak but measurable decay component of approximately 2 ps is indicated. C1 Pacific NW Lab, William R Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Hess, WP (reprint author), Pacific NW Lab, William R Wiley Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. NR 26 TC 8 Z9 8 U1 0 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0947-8396 J9 APPL PHYS A-MATER JI Appl. Phys. A-Mater. Sci. Process. PD DEC PY 1999 VL 69 SU S BP S153 EP S157 DI 10.1007/s003399900205 PG 5 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 287WV UT WOS:000085530400029 ER PT J AU Komashko, AM Feit, MD Rubenchik, AM Perry, MD Banks, PS AF Komashko, AM Feit, MD Rubenchik, AM Perry, MD Banks, PS TI Simulation of material removal efficiency with ultrashort laser pulses SO APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING LA English DT Article; Proceedings Paper CT 5th International Conference on Laser Ablation COLA'99 CY JUL 19-23, 1999 CL GOTTINGEN, GERMANY ID SOLID TARGETS; SIMPLE METAL; ABSORPTION; ABLATION AB Understanding physical processes accompanying ablation is necessary for the optimal use of ultrashort laser pulse (USLP) material processing. We describe the implementation of self-consistent electromagnetic propagation-energy absorption in our numerical models. We evaluate absorption as a function of the pulse duration, energy, angle of incidence and polarization. We formulate a measure of material removal and use it to estimate the effect of energy, pulselength and prepulses on material removal. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Komashko, AM (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,Mail Stop L-477, Livermore, CA 94550 USA. RI Feit, Michael/A-4480-2009 NR 15 TC 30 Z9 30 U1 0 U2 4 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0947-8396 J9 APPL PHYS A-MATER JI Appl. Phys. A-Mater. Sci. Process. PD DEC PY 1999 VL 69 SU S BP S95 EP S98 DI 10.1007/s003399900217 PG 4 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 287WV UT WOS:000085530400017 ER PT J AU Langford, SC Dickinson, JT Alexander, ML AF Langford, SC Dickinson, JT Alexander, ML TI The production of sub-micron sodium nitrate particles by laser ablation SO APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING LA English DT Article; Proceedings Paper CT 5th International Conference on Laser Ablation COLA'99 CY JUL 19-23, 1999 CL GOTTINGEN, GERMANY ID DEFECTS; MGO AB Laser ablation is a useful source of particles for chemical analysis by inductively coupled mass spectroscopy in many applications. Optimum particle transport and ionization requires particles with sizes in the range 0.1-2 mu m. Significant questions remain as to the mechanisms behind particle production by laser ablation. In this work, we collect and observe particles produced from single-crystal sodium nitrate during irradiation at 1.06 mu m as a function of fluence and explore the possibility that laser-induced fracture may produce suitable particles. At fluences between 3 and 4 J/cm(2) single laser pulses incident on cleaved samples produce large numbers of fracture particles as a result of the fracture of undercut cleavage steps. Polished samples, lacking cleavage steps, yield few, if any, particles. As the fluence is raised to 5 J/cm(2), a small breakdown plume is observed and large melted droplets (similar to 10 mu m in diameter) are produced from both cleaved and polished targets, presumably by spallation of a thick melted layer. Particle generation by fracture has the potential to produce particles whose composition closely matches the local sample composition. C1 Washington State Univ, Dept Phys, Pullman, WA 99164 USA. Pacific NW Lab, Richland, WA 99352 USA. RP Langford, SC (reprint author), Washington State Univ, Dept Phys, Pullman, WA 99164 USA. NR 10 TC 1 Z9 1 U1 2 U2 3 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0947-8396 J9 APPL PHYS A-MATER JI Appl. Phys. A-Mater. Sci. Process. PD DEC PY 1999 VL 69 SU S BP S647 EP S650 DI 10.1007/s003390051496 PG 4 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 287WV UT WOS:000085530400139 ER PT J AU Pedraza, AJ Fowlkes, JD Lowndes, DH AF Pedraza, AJ Fowlkes, JD Lowndes, DH TI Self-organized silicon microcolumn arrays generated by pulsed laser irradiation SO APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING LA English DT Article; Proceedings Paper CT 5th International Conference on Laser Ablation COLA'99 CY JUL 19-23, 1999 CL GOTTINGEN, GERMANY ID FILMS; DEPOSITION; SURFACE; GROWTH; ARF AB Cumulative nanosecond pulsed excimer laser irradiation of silicon produces an array of high-aspect-ratio microcolumns that protrude well above the initial surface. The growth of these microcolumns is strongly affected by the gas environment, being enhanced in air or in other oxygen-containing atmosphere. An array of very large and complex conical structures that also protrude above the surface is formed if the irradiation is performed in sulfur hexafluoride (SF(6)). Kinetics studies of microcolumn growth show that: (i) A certain number of pulses is required to initiate growth of microcolumns; (ii) column nucleation is inhomogeneous, taking place al ways at the edges of deep grooves or pits; (iii)growth is fast with the earlier pulses but slows down to a halt when the columns reach a certain length. These studies show that columns nucleate and grow by continuous influx of silicon with each laser pulse. It is proposed that the axial growth of microcolumns and cones is due to the deposition of atoms or clusters at their tips. The column/cone tips are melted during irradiation and act as preferred sites for deposition, resulting in a very high axial growth rate. The contribution of etching and ablation to the flux of silicon-rich vapor produced during irradiation is discussed. The mechanism of columnar growth is compared with the vapor-liquid-solid method to grow silicon whiskers. C1 Univ Tennessee, Dept Mat Sci & Engn, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Pedraza, AJ (reprint author), Univ Tennessee, Dept Mat Sci & Engn, Knoxville, TN 37996 USA. EM apedraza@utk.edu; vdh@ornl.gov NR 32 TC 32 Z9 33 U1 1 U2 3 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0947-8396 J9 APPL PHYS A-MATER JI Appl. Phys. A-Mater. Sci. Process. PD DEC PY 1999 VL 69 SU S BP S731 EP S734 DI 10.1007/s003390051517 PG 4 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 287WV UT WOS:000085530400160 ER PT J AU Rouleau, CM Kang, S Lowndes, DH AF Rouleau, CM Kang, S Lowndes, DH TI Pulsed KrF laser deposited GaN/TiN/Si(111) heterostructures by sequential TiN and liquid Ga laser ablation SO APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING LA English DT Article; Proceedings Paper CT 5th International Conference on Laser Ablation COLA'99 CY JUL 19-23, 1999 CL GOTTINGEN, GERMANY ID CHEMICAL-VAPOR-DEPOSITION; NITRIDE THIN-FILMS; EPITAXIAL-GROWTH; SILICON; SUBSTRATE; SAPPHIRE; ORIENTATION; LAYERS AB GaN/TiN heterostructures were deposited on 4 degrees miscut Si(lll) substrates by pulsed KrF laser ablation of TiN through vacuum, followed by reactive pulsed KrF laser ablation of liquid Ga through 70-75 mTorr of microwave-activated NH3. Deposition temperatures of 950 degrees C and 1050 degrees C were employed for the TiN layer while 900 degrees C was employed for the GaN layer. The targets were positioned 5 cm from the substrate and ablated by using a reimaging beamline at a nominal energy density of 3-4 J/cm(2). X-ray diffraction (XRD) revealed a highly textured heterostructure with GaN(0001)//TiN(111)//Si(111) and with a rocking curve width for both GaN(0001) and TiN(111) equal to similar to 1.1 degrees. The mosaic spread through the TiN(001) reflection was similar to 1.3 degrees, whereas that of the GaN(1011) was undetectable because of low S/N. Scanning electron microscopy revealed large oriented 10 mu m-sized hexagonal crystallites decorating large depressions in the TiN film with many smaller pits also present. The effect of substrate processing and TiN film processing on pit formation was explored. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. RP Rouleau, CM (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. RI Rouleau, Christopher/Q-2737-2015 OI Rouleau, Christopher/0000-0002-5488-3537 NR 26 TC 6 Z9 6 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0947-8396 J9 APPL PHYS A-MATER JI Appl. Phys. A-Mater. Sci. Process. PD DEC PY 1999 VL 69 SU S BP S441 EP S445 DI 10.1007/s003390051434 PG 5 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 287WV UT WOS:000085530400090 ER PT J AU Russo, RE Mao, XL Liu, HC Yoo, JH Mao, SS AF Russo, RE Mao, XL Liu, HC Yoo, JH Mao, SS TI Time-resolved plasma diagnostics and mass removal during single-pulse laser ablation SO APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING LA English DT Article; Proceedings Paper CT 5th International Conference on Laser Ablation COLA'99 CY JUL 19-23, 1999 CL GOTTINGEN, GERMANY AB Laser ablation processes occurring over several orders of magnitude in time were investigated by using time-resolved spectroscopy, shadowgraphs and interferograms. A picosecond ablation plasma was measured with an electron density on the order of 10(20) cm(-3) originating from the breakdown of air. The longitudinal expansion of this plasma was suppressed due to the development of a strong space- charge field. At post-pulse times, the lateral (radial) expansion of the plasma was found to follow the relation, r similar to t(1/2), consistent with the expansion from an instantaneous line source of energy. The electron number density and temperature were deduced by measuring spectroscopic emission-line broadening during the early phase (30-300 ns) of a mass (atomic/ionic) plasma. These properties were measured as a function of the delay time and irradiance. Possible mechanisms such as inverse bremsstrahlung and self-regulation were used to describe the data before an explosion threshold of 20 GW/cm(2). The laser self-focusing and critical temperature are discussed to explain dramatic changes in these properties after the irradiance threshold. On the microsecond time scale, the surface explodes and large (> mu m) particles are ejected. Mass removed from single-crystal silicon by high power (10(9)-10(11)W/cm(2)) single-pulse laser ablation is studied by measuring the crater morphology. Time-resolved shadowgraph images show that the rapid increase in the crater depth at the threshold corresponds to large-size droplets leaving the surface; This rapid growth of the crater volume is attributed to explosive boiling. C1 Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Chinese Acad Sci, Guangzhou Inst Geochem, Canton 510640, Peoples R China. RP Russo, RE (reprint author), Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. NR 21 TC 60 Z9 62 U1 4 U2 21 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0947-8396 J9 APPL PHYS A-MATER JI Appl. Phys. A-Mater. Sci. Process. PD DEC PY 1999 VL 69 SU S BP S887 EP S894 DI 10.1007/s003390051553 PG 8 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 287WV UT WOS:000085530400196 ER PT J AU Russo, RE Klunder, GL Grant, P Andresen, BD AF Russo, RE Klunder, GL Grant, P Andresen, BD TI Laser ablation ion-storage time-of-flight mass spectrometry SO APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING LA English DT Article; Proceedings Paper CT 5th International Conference on Laser Ablation COLA'99 CY JUL 19-23, 1999 CL GOTTINGEN, GERMANY AB A new mass spectrometer system was developed for studying laser ablation and performing analytical chemistry. The system is based on an ion trap geometry used in ion-storage (IS) mode, coupled with a reflectron time-of-flight mass spectrometer (TOFMS). The LA-IS/TOF-MS can be used for MALDI or direct ionization of samples on a probe tip. The system configuration and related operating principles for accurately measuring low concentrations of isotopes will be described. Preliminary measurements identified ultra-trace contaminants of Ag, Sn, and Sb in a Pb target with single laser-shot experiments. Survey analyses of uranyl acetate, hair samples, and mushrooms demonstrated that this technology can be applied to a wide range of sample materials. C1 Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Lawrence Livermore Natl Lab, Forens Sci Ctr, Livermore, CA 94550 USA. RP Russo, RE (reprint author), Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 6 TC 10 Z9 10 U1 0 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0947-8396 J9 APPL PHYS A-MATER JI Appl. Phys. A-Mater. Sci. Process. PD DEC PY 1999 VL 69 SU S BP S895 EP S897 DI 10.1007/s003390051554 PG 3 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 287WV UT WOS:000085530400197 ER PT J AU Sasaki, T Koshizaki, N Beck, KM AF Sasaki, T Koshizaki, N Beck, KM TI Comparison of Pt/TiO2 nanocomposite films prepared by sputtering and pulsed laser deposition SO APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING LA English DT Article; Proceedings Paper CT 5th International Conference on Laser Ablation COLA'99 CY JUL 19-23, 1999 CL GOTTINGEN, GERMANY ID TIO2 FILMS; OPTICAL-PROPERTIES; ANATASE; AU AB Pt/TiO2 nanocomposite films were prepared by sputtering and pulsed laser deposition (PLD). The Pt/Ti atomic ratios in the films deposited by the PLD were smaller than those in the ablation targets and those in the films prepared by sputtering. At low Pt concentration, Pt is deposited as PtO2 in the films prepared by sputtering, whereas metallic Pt is deposited in the films prepared by PLD. The Pt nanoparticle size in the as-deposited Pt/TiO2 nanocomposite films prepared by PLD was about 30 nm, which is quite large compared to the 1-2-nm size in the sputter-deposited films. Pt nanoparticles were produced in the growth processes via surface diffusion, which can be reflected by the kinetic energy of the chemical species spread from the target. It can be inferred from the optical measurements of heated Pt/TiO2 nanocomposite films that new energy levels are produced in the band gap of TiO2 by the homogeneous dispersion of Pt nanoparticles in the TiO2 matrix. C1 Natl Inst Mat & Chem Res, Tsuchiura, Ibaraki 3058565, Japan. Pacific NW Natl Lab, William R Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Sasaki, T (reprint author), Natl Inst Mat & Chem Res, 1-1 Higashi, Tsuchiura, Ibaraki 3058565, Japan. RI Koshizaki, Naoto/E-2024-2011 NR 17 TC 6 Z9 6 U1 1 U2 7 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0947-8396 J9 APPL PHYS A-MATER JI Appl. Phys. A-Mater. Sci. Process. PD DEC PY 1999 VL 69 SU S BP S771 EP S774 DI 10.1007/s003390051526 PG 4 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 287WV UT WOS:000085530400169 ER PT J AU Wang, ZQ Yeung, ES AF Wang, ZQ Yeung, ES TI Fluorescence imaging of glutamate release in neurons SO APPLIED SPECTROSCOPY LA English DT Article DE imaging; glutamate; microscopy; neurons ID AMINO-ACID NEUROTRANSMITTERS; GAMMA-AMINOBUTYRIC ACID; CENTRAL NERVOUS-SYSTEM; CAPILLARY ELECTROPHORESIS; LIQUID-CHROMATOGRAPHY; SYNAPTIC VESICLES; PROTEIN-KINASE; SINGLE CELLS; BRAIN; ASTROCYTES AB A noninvasive detection scheme based on glutamate dehydrogenase (GDH) enzymatic assay combined with microscopy was developed to measure the glutamate release in cultured cells from the central nervous system (CNS). The enzyme reaction is very specific and sensitive. The detection limit with charge-coupled device (CCD) imaging is down to mu M levels of glutamate with reasonable response time (similar to 30 s). The standard glutamate test shows a linear response over 3 orders of magnitude, from mu M to 0.1 mM range. The kt vitro monitoring of glutamate release from cultured neuron cells demonstrated excellent spatial and temporal resolution. 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. NR 49 TC 4 Z9 4 U1 2 U2 3 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA 201B BROADWAY ST, FREDERICK, MD 21701 USA SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD DEC PY 1999 VL 53 IS 12 BP 1502 EP 1506 DI 10.1366/0003702991946235 PG 5 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA 272JU UT WOS:000084647400007 ER PT J AU Rusak, DA Anderson, JE Keller, RA Wilkerson, CW Kunhardt, EE AF Rusak, DA Anderson, JE Keller, RA Wilkerson, CW Kunhardt, EE TI Signal dependence on light modulation frequency in optogalvanic spectroscopy SO APPLIED SPECTROSCOPY LA English DT Article DE optogalvanic spectroscopy; modulation; direct-current discharge; noise power spectrum C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Stevens Inst Technol, Dept Phys & Engn Phys, Hoboken, NJ 07030 USA. RP Wilkerson, CW (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. NR 8 TC 2 Z9 2 U1 0 U2 0 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA 201B BROADWAY ST, FREDERICK, MD 21701 USA SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD DEC PY 1999 VL 53 IS 12 BP 1651 EP 1653 DI 10.1366/0003702991946154 PG 3 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA 272JU UT WOS:000084647400027 ER PT J AU Hayter, SJ Torcellini, PA Judkoff, P AF Hayter, SJ Torcellini, PA Judkoff, P TI Optimizing building and HVAC systems SO ASHRAE JOURNAL LA English DT Article C1 Natl Renewable Energy Lab, Low Energy Bldg Res Project, Golden, CO 80401 USA. NREL, Ctr Bldg & Thermal Syst, Golden, CO USA. RP Hayter, SJ (reprint author), Natl Renewable Energy Lab, Low Energy Bldg Res Project, Golden, CO 80401 USA. NR 0 TC 3 Z9 3 U1 0 U2 0 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 DEC PY 1999 VL 41 IS 12 BP 46 EP 49 PG 4 WC Thermodynamics; Construction & Building Technology; Engineering, Mechanical SC Thermodynamics; Construction & Building Technology; Engineering GA 263XM UT WOS:000084150600012 ER PT J AU Gray, RO Kaye, AB AF Gray, RO Kaye, AB TI HR 8799: A link between gamma Doradus variables and gamma Bootis stars SO ASTRONOMICAL JOURNAL LA English DT Article DE stars : abundances; stars : chemically peculiar; stars : individual (HR 8799); stars : variables : other ID SPECTRAL CLASSIFICATION; LAMBDA AB On the basis of a new classification-resolution spectrum, we find that HR 8799, a known member of the newly discovered gamma Doradus variable star class, is a lambda Bootis star. Spectral synthesis, in conjunction with fluxes from visible spectrophotometry and the TD-1 satellite, yields T-eff = 7430 K, log g = 4.35, microturbulent velocity xi(t) = 2.7 km s(-1), and metallicity [M/H] = -0.47 for HR 8799, confirming its metal-weak nature. HR 8799 is also a "Vega-like" star in that it shows excess flux at 60 mu m, probably due to a circumstellar dust shell or disk. Thus, this star links three astrophysically interesting classes of stars and may provide potentially important constraints on the physics of, and the interconnections between, the lambda Bootis phenomenon and the gamma Doradus pulsation phenomenon. C1 Appalachian State Univ, Dept Phys & Astron, Boone, NC 28608 USA. Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Los Alamos, NM 87545 USA. RP Gray, RO (reprint author), Appalachian State Univ, Dept Phys & Astron, Boone, NC 28608 USA. NR 31 TC 62 Z9 62 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD DEC PY 1999 VL 118 IS 6 BP 2993 EP 2996 DI 10.1086/301134 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 274KY UT WOS:000084766100032 ER PT J AU Kaye, AB Henry, GW Fekel, FC Gray, RO Rodriguez, E Martin, S Gies, DR Bagnuolo, WG Hall, DS AF Kaye, AB Henry, GW Fekel, FC Gray, RO Rodriguez, E Martin, S Gies, DR Bagnuolo, WG Hall, DS TI HD 62454 and HD 68192: Two new gamma Doradus variables SO ASTRONOMICAL JOURNAL LA English DT Article DE stars : oscillations; stars : variables : other ID TOMOGRAPHIC SEPARATION; COMPOSITE SPECTRA; STARS; PHOTOMETRY; UVBY AB We present multilongitude, multicolor photometry and simultaneous high-resolution, high signal-to-noise spectroscopy of the newly discovered gamma Doradus variables HD 62454 and HD 68192. From combined Johnson and Stromgren data, we are able to identify five independent periods in HD 62454 and two stable periods in HD 68192. The data presented are sufficient to rule out all physically meaningful types of variations, with the one exception of the high-order, low-degree, nonradial gravity-mode pulsations that are believed to be at work in gamma Doradus stars. We also find that HD 62454 is a double-lined spectroscopic binary and we present an orbital solution. C1 Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Los Alamos, NM 87545 USA. Tennessee State Univ, Ctr Excellence Informat Syst, Nashville, TN 37203 USA. Appalachian State Univ, Dept Phys & Astron, Boone, NC 28608 USA. CSIC, Inst Astrofis Andalucia, E-18080 Granada, Spain. Georgia State Univ, Dept Phys & Astron, Atlanta, GA 30303 USA. Vanderbilt Univ, Dyer Observ, Brentwood, TN USA. RP Kaye, AB (reprint author), Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, X-TA,MS B-220, Los Alamos, NM 87545 USA. RI Lujan Center, LANL/G-4896-2012; Martin-Ruiz, Susana/B-6768-2013; OI Rodriguez, Eloy/0000-0001-6827-9077 NR 29 TC 15 Z9 15 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD DEC PY 1999 VL 118 IS 6 BP 2997 EP 3005 DI 10.1086/301136 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 274KY UT WOS:000084766100033 ER PT J AU Gliozzi, M Brinkmann, W Laurent-Muehleisen, SA Takalo, LO Sillanpaa, A AF Gliozzi, M Brinkmann, W Laurent-Muehleisen, SA Takalo, LO Sillanpaa, A TI ROSAT HRI observations of radio-loud AGN SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : active; galaxies : fundamental parameters; galaxies : ISM; galaxies : nuclei; X-rays : galaxies ID BL LACERTAE OBJECTS; ALL-SKY SURVEY; ACTIVE GALAXIES; IDENTIFICATIONS; CLUSTER AB We present the results of three ROSAT HRI observations of AGN expected to reside in clusters of galaxies. Although the exposures were truncated by the premature end of the ROSAT mission, valuable information could be achieved which greatly improved upon the previous PSPC results. For RGB 1745+398 we could separate the cluster emission from that of the BL Lac and could confirm the cluster parameters obtained from optical follow-up observations. In MRC 0625-536 the flux from the central point source contributes less than 3% to the total X-ray flux and the eastern component of the dumbbell galaxy seems to be the X-ray emitter. RXJ1234.6+2350 appears to be extended in X-rays. The X-ray flux is centered on a quasar, but optical spectroscopy indicates that the nearby radio galaxies reside in a previously unknown cluster at redshift z similar to 0.134. C1 Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. Univ Calif Davis, Livermore, CA 94450 USA. Univ Calif Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94450 USA. Univ Turku, Tuorla Observ, Piikkio 215000, Finland. RP Gliozzi, M (reprint author), Max Planck Inst Extraterr Phys, Postfach 1603, D-85740 Garching, Germany. EM mgliozzi@xray.mpe.mpg.de NR 23 TC 6 Z9 6 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD DEC PY 1999 VL 352 IS 2 BP 437 EP 442 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 271ZF UT WOS:000084625000021 ER PT J AU De Breuck, C van Breugel, W Minniti, D Miley, G Rottgering, H Stanford, SA Carilli, C AF De Breuck, C van Breugel, W Minniti, D Miley, G Rottgering, H Stanford, SA Carilli, C TI VLT spectroscopy of the z=4.11 Radio Galaxy TN J1338-1942 SO ASTRONOMY & ASTROPHYSICS LA English DT Letter DE galaxies : active; galaxies : individual : TN J1338-1942; cosmology : observations ID STELLAR POPULATIONS; ALPHA EMISSION; REDSHIFT; DUST; ABSORPTION; UNIVERSE; QUASARS AB We present optical. infrared and radio data of the z = 4.11 radio galaxy TN J1338-1942 including an intermediate resolution spectrum obtained with FORS1 on the VLT Antu telescope. TN J1338-1942 was the first z > 4 radio galaxy to be discovered in the southern hemisphere and is one of the most luminous Ly alpha objects in its class. The Ly alpha and rest-frame optical emission-appear co-spatial with the brightest radio hotspot of this very asymmetric radio source, suggesting extremely strong interaction with dense ambient clouds. The Ly alpha is spatially extended by similar to 4 " (30 kpc), has an enormous rest-frame equivalent width, W-lambda(rest) = 210 +/- 50 Angstrom, and has a spectral profile that is very asymmetric with a deficit towards the blue. We interpret this blue-ward asymmetry as being due to absorption of the Ly alpha photons by cold gas in a turbulent halo surrounding the radio galaxy and show that the required neutral hydrogen column density must be in the range 3.5-13 x 10(19) cm(-2). The two-dimensional spectrum indicates that the extent of the absorbing gas is comparable (or even larger) than the: 4 " (30 kpc) Ly alpha emitting region. The VLT observations are sufficiently sensitive to detect the continuum flux both blue-ward and red-ward of the Ly alpha emission, allowing us to measure the Ly alpha forest continuum break (Ly alpha 'discontinuity', D-A) and the Lyman limit. We measure a D-A = 0.37 +/- 0.1, which is similar to 0.2 lower than the values found for quasars at this redshift. We interpret this difference as possibly due to a bias towards large D-A introduced in high-redshift quasar samples that are selected on the basis of specific optical colors. If such a bias would exist in optically selected quasars, and even in samples of Lyman break galaxies -, then the space density of both classes of object will be underestimated. Furthermore, the average H I column density along cosmological lines of sight as determined using quasar absorption lines would be overestimated. Because of their radio-based selection, we argue that z > 4 radio galaxies are excellent objects for investigating D-A statistics. C1 Sterrewacht Leiden, NL-2300 RA Leiden, Netherlands. Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. Pontificia Univ Catolica Chile, Santiago 22, Chile. Natl Radio Astron Observ, Socorro, NM 87801 USA. RP De Breuck, C (reprint author), Sterrewacht Leiden, Postbus 9513, NL-2300 RA Leiden, Netherlands. EM debreuck@strw.leidenuniv.nl; will@igpp.llnl.gov; dante@astro.puc.cl; miley@strw.leidenuniv.nl; rottgeri@strw.leideuniv.nl; adam@igpp.llnl.gov; ccarilli@nrao.edu NR 42 TC 35 Z9 36 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD DEC PY 1999 VL 352 IS 1 BP L51 EP L56 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 266AX UT WOS:000084279400011 ER PT J AU Stancil, PC Schultz, DR Kimura, M Gu, JP Hirsch, G Buenker, RJ AF Stancil, PC Schultz, DR Kimura, M Gu, JP Hirsch, G Buenker, RJ TI Charge transfer in collisions of O(+) with H and H(+) with O SO ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES LA English DT Article DE atomic processes; ISM : atoms; interplanetary medium; comets : general; planets and satellites : individual : Jupiter ID FINE-STRUCTURE EXCITATION; SINGLE-ELECTRON-CAPTURE; TOTAL CROSS-SECTIONS; ASYMMETRIC COLLISIONS; ATOMIC OXYGEN; MULTIELECTRON ATOMS; FAST PROTONS; IONS; HYDROGEN; APPROXIMATION AB Cross sections and rate coefficients for total and fine-structure resolved charge transfer in collisions of Of with H and H(+) with O are presented for collision energies between 0.1 meV/u and 10 MeV/u and temperatures between 10 and 10(7) K. The results are obtained utilizing new quantal and semiclassical molecular-orbital close-coupling, classical trajectory Monte Carlo, and continuum distorted wave calculations in conjunction with previous experimental and theoretical data. Applications to various astrophysical and atmospheric environments are discussed. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Yamaguchi Univ, Grad Sch Sci & Engn, Ube, Yamaguchi 755, Japan. Berg Univ Wuppertal, D-42097 Wuppertal, Germany. RP Stancil, PC (reprint author), Oak Ridge Natl Lab, Div Phys, POB 2008, Oak Ridge, TN 37831 USA. EM stancil@mail.phy.ornl.gov; schultz@mail.phy.ornl.gov; mineo@rikaxp.riken.go.jp; jgu@ist.ucf.edu; buenker@wrcs1.urz.uni-wuppertal.de NR 60 TC 67 Z9 67 U1 1 U2 3 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0365-0138 J9 ASTRON ASTROPHYS SUP JI Astron. Astrophys. Suppl. Ser. PD DEC PY 1999 VL 140 IS 2 BP 225 EP 234 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 264PD UT WOS:000084189900009 ER PT J AU Fan, XH Strauss, MA Gunn, JE Lupton, RH Carilli, CL Rupen, MP Schmidt, GD Moustakas, LA Davis, M Annis, J Bahcall, NA Brinkmann, J Brunner, RJ Csabai, I Doi, M Fukugita, M Heckman, TM Hennessy, GS Hindsley, RB Ivezic, Z Knapp, GR Lamb, DQ Munn, JA Pauls, AG Pier, JR Rockosi, CM Schneider, DP Szalay, AS Tucker, DL York, DG AF Fan, XH Strauss, MA Gunn, JE Lupton, RH Carilli, CL Rupen, MP Schmidt, GD Moustakas, LA Davis, M Annis, J Bahcall, NA Brinkmann, J Brunner, RJ Csabai, I Doi, M Fukugita, M Heckman, TM Hennessy, GS Hindsley, RB Ivezic, Z Knapp, GR Lamb, DQ Munn, JA Pauls, AG Pier, JR Rockosi, CM Schneider, DP Szalay, AS Tucker, DL York, DG TI The discovery of a high-redshift quasar without emission lines from Sloan Digital Sky Survey commissioning data SO ASTROPHYSICAL JOURNAL LA English DT Article DE quasars : individual (SDSS 1533-00); radio continuum : galaxies; X-rays : galaxies ID BL LACERTAE OBJECTS; SPECTROPHOTOMETRY; EVOLUTION AB We report observations of a luminous unresolved object at redshift z = 4.62, with a featureless optical spectrum redward of the Ly alpha forest region, discovered from Sloan Digital Sky Survey commissioning data. The redshift is determined by the onset of the Ly alpha forest at lambda similar to 6800 Angstrom and a Lyman limit system at lambda = 5120 Angstrom. A strong Ly alpha absorption system with weak metal absorption lines at z = 4.58 is also identified in the spectrum. The object has a continuum absolute magnitude of -26.6 at 1450 Angstrom in the rest frame (h(0) = 0.5, q(0) = 0.5) and therefore cannot be an ordinary galaxy. It shows no radio emission (the 3 sigma upper limit of its flux at 6 cm is 60 mu Jy), indicating a radio-to-optical flux ratio at least as small as that of the radio-weakest BL Lacertae objects known. It is also not linearly polarized to a 3 sigma upper limit of 4% in the observed I band. Therefore, it is either the most distant BL Lac object known to date, with very weak radio emission, or a new type of unbeamed quasar, whose broad emission line region is very weak or absent. C1 Princeton Univ Observ, Princeton, NJ 08544 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Univ Oxford, Dept Astrophys, Oxford OX1 3RH, England. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Apache Point Observ, Sunspot, NM 88349 USA. Johns Hopkins Univ, Henry A Rowland Dept Phys & Astron, Baltimore, MD 21218 USA. CALTECH, Dept Astron, Pasadena, CA 91125 USA. Eotvos Lorand Univ, Dept Phys Complex Syst, H-1117 Budapest, Hungary. Univ Tokyo, Dept Astron, Tokyo 1130033, Japan. Univ Tokyo, Inst Cosm Ray Res, Tokyo 1888502, Japan. USN Observ, Washington, DC 20392 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. USN Observ, Flagstaff Stn, Flagstaff, AZ 86002 USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Univ Tokyo, Res Ctr Early Universe, Tokyo 1130033, Japan. RP Fan, XH (reprint author), Princeton Univ Observ, Peyton Hall, Princeton, NJ 08544 USA. RI Csabai, Istvan/F-2455-2012 NR 26 TC 73 Z9 73 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 1 PY 1999 VL 526 IS 2 BP L57 EP L60 DI 10.1086/312382 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 263GG UT WOS:000084116600001 ER PT J AU Iwamoto, K Brachwitz, F Nomoto, K Kishimoto, N Umeda, H Hix, WR Thielemann, FK AF Iwamoto, K Brachwitz, F Nomoto, K Kishimoto, N Umeda, H Hix, WR Thielemann, FK TI Nucleosynthesis in Chandrasekhar mass models for type IA supernovae and constraints on progenitor systems and burning-front propagation SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Review DE nuclear reactions, nucleosynthesis, abundances; stars : interiors; supernovae : general ID WHITE-DWARF MODELS; METAL-POOR STARS; CARBON DEFLAGRATION SUPERNOVAE; WEAK-INTERACTION RATES; EXTREME HALO STARS; X-RAY SOURCES; CHEMICAL EVOLUTION; LIGHT CURVES; EXPLOSIVE NUCLEOSYNTHESIS; PRESUPERNOVA EVOLUTION AB The major uncertainties involved in the Chandrasekhar mass models for Type Ia supernovae (SNe Ia) are related to the companion star of their accreting white dwarf progenitor (which determines the accretion rate and consequently the carbon ignition density) and the flame speed after the carbon ignition. We calculate explosive nucleosynthesis in relatively slow deflagrations with a variety of deflagration speeds and ignition densities to put new constraints on the above key quantities. The abundance of the Fe group, in particular of neutron-rich species like (48)Ca, (50)Ti, (54)Cr, (54,58)Fe, and (58)Ni, is highly sensitive to the electron captures taking place in the central layers. The yields obtained from such a slow central deflagration, and from a fast deflagration or delayed detonation in the outer layers, are combined and put to comparison with solar isotopic abundances. To avoid excessively large ratios of (54)Cr/(56)Fe and (50)Ti/(56)Fe, the central density of the "average" white dwarf progenitor at ignition should be as low as less than or similar to 2 x 10(9) g cm(-3). To avoid the overproduction of (58)Ni and (54)Fe, either the flame speed should not exceed a few percent of the sound speed in the central low Y(e) layers or the metallicity of the average progenitors has to be lower than solar. Such low central densities can be realized by a rapid accretion as fast as (M) over dot greater than or similar to 1 x 10(-7) M. yr(-1). In order to reproduce the solar abundance of (48)Ca, one also needs progenitor systems that undergo ignition at higher densities. Even the smallest laminar flame speeds after the low-density ignitions would not produce sufficient amount of this isotope. We also found that the total amount of (56)Ni, the Si-Ca/Fe ratio, and the abundance of some elements like Mn and Cr (originating from incomplete Si burning), depend on the density of the deflagration-detonation transition in delayed detonations. Our nucleosynthesis results favor transition densities slightly below 2.2 x 10(7) g cm(-3). C1 Univ Tokyo, Dept Astron, Tokyo 1130033, Japan. Univ Tokyo, Sch Sci, Res Ctr Early Universe, Tokyo 1130033, Japan. Univ Calif Santa Barbara, Inst Theoret Phys, Santa Barbara, CA 93106 USA. Univ Basel, Dept Phys & Astron, CH-4056 Basel, Switzerland. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Iwamoto, K (reprint author), Univ Tokyo, Dept Astron, Tokyo 1130033, Japan. RI Hix, William/E-7896-2011; Nomoto, Ken'ichi/A-4393-2011 OI Hix, William/0000-0002-9481-9126; NR 140 TC 664 Z9 665 U1 1 U2 9 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD DEC PY 1999 VL 125 IS 2 BP 439 EP 462 DI 10.1086/313278 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 277PA UT WOS:000084940900008 ER PT J AU Saylor, RD Easter, RC Chapman, EG AF Saylor, RD Easter, RC Chapman, EG TI Simulation of the tropospheric distribution of carbon monoxide during the 1984 MAPS experiment SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE numerical simulation; atmospheric chemistry modeling; biomass burning; satellite measurements ID GLOBAL CO PRODUCTION; SOUTHERN-HEMISPHERE; CLOUD TRANSPORT; REFERENCE SCALE; TRACE GASES; MODEL; EMISSIONS; OZONE; CHEMISTRY; AIR AB A global, three-dimensional tropospheric chemistry model was used to perform simulations of the tropospheric distribution of carbon monoxide (CO) coinciding with NASA's Measurement of Air Pollution from Satellites (MAPS) experiment which took place during 5-13 October 1984. Archived meteorological data for September and October, 1984, were obtained from the European Centre for Medium-Range Weather Forecasting and used to drive the offline chemical transport model simulations. Base-case CO emissions were generated by applying emission factors to compiled inventories for related or co-emitted trace species. Simulation results from September and October have been compared with a recent re-release of the 1984 MAPS data and with in situ correlative data taken during the MAPS mission. Because of unrealistically large spatial variability in N(2)O mixing ratios measured concurrently by MAPS, model results were also compared with an adjusted CO data set generated by assuming that errors in N(2)O measured mixing ratios were correlated with errors in the MAPS CO data. These comparisons, in conjunction with simulations probing model sensitivities, led to the conclusion that biomass burning CO emissions from central and southern Africa may have been larger during September and October, 1984, than our initial best estimate based on the CO(2) emissions data of Hao et al. (1990. Fire in the Tropical Biota; Ecosystem Processes and Global Challenges. Springer, Berlin, pp. 440-462; 1994. Global Biogeochemical Cycles 8, 495-503). This result is in disagreement with recent estimates of biomass burning emissions from Africa (Scholes et al., 1996, Journal of Geophysical Research 101, 23677-23682) which are smaller than previously thought for emissions from this region. Although unknown model deficiencies cannot be conclusively ruled out, model sensitivity studies indicate that increased CO emissions from central and southern Africa offer the best explanation for reducing observed differences between model results and MAPS data for this time period. Our results, in combination with a disparity in recent CO emission estimates from this region (Scholes et al., 1996; Hao et al., 1996, Journal of Geophysical Research 101, 23577-23584), and in light of recent indications of highly variable biomass burning activities from the tropical western Pacific (Folkins et al., 1997, Journal of Geophysical Research 102, 13291-13299), seem to suggest that biomass burning emissions exhibit significant year-to-year variability. This large variability of emissions sources makes the accurate simulation of specific time periods very difficult and suggests that biomass burning trace species inventories may have to be developed specifically for each simulated time period, employing satellite-derived information on fire coverage and flame intensity. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. Pacific NW Lab, Richland, WA 99352 USA. RP Saylor, RD (reprint author), Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. RI Chapman, Elaine/K-8756-2012; Saylor, Rick/D-1252-2014 OI Saylor, Rick/0000-0003-4835-8290 NR 70 TC 2 Z9 2 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD DEC PY 1999 VL 33 IS 28 BP 4675 EP 4694 DI 10.1016/S1352-2310(99)00244-7 PG 20 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 247YU UT WOS:000083249200012 ER PT J AU Gaffney, JS Marley, NA Cunningham, MM Doskey, PV AF Gaffney, JS Marley, NA Cunningham, MM Doskey, PV TI Measurements of peroxyacyl nitrates (PANS) in Mexico City: implications for megacity air quality impacts on regional scales SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE peroxyacyl nitrates; peroxyacetyl nitrate; Mexico City air quality; megacities; butene sources; nonmethane hydrocarbons ID NONMETHANE ORGANIC-COMPOUNDS; LIQUEFIED PETROLEUM GAS; METROPOLITAN-AREA; FORMALDEHYDE; HYDROCARBONS; ATMOSPHERE; EMISSIONS; BASIN; SITE AB Peroxyacyl nitrates (PANs) were measured using gas chromatography with electron capture detection (GC/ECD) in north central Mexico City during February-March of 1997. Peroxyacetyl nitrate (PAN) was observed to exceed 30 ppb during five days of the study, with peroxypropionyl nitrate (PPN) and peroxybutryl nitrate (PBN) reaching 6 and 1 ppb maximum, respectively. Levels of total PANs typically exceeded 10 ppb during the period of measurement and showed a very strong diurnal variation with PANs maximum during the early afternoon and falling to less than 0.1 ppb during the evening hours. These levels of PANs are the highest reported values in North America (and the world) for an urban center, since levels of approximately 30 ppb were reported during the late 1970s in the Los Angeles area (South Coast Air Basin, Tuazon et al., 1978), Hydrocarbon measurements indicate that the levels of olefins, specifically butenes are significant in Mexico City. A time series taken of source indicator hydrocarbons taken before and during a Mexican National Holiday with reduced automobile traffic clearly show that mobile sources of butenes are as important as liquefied petroleum gas. Observations of 10-40 ppb C methyl-t-butyl ether (MTBE) are consistent with MTBE/gasoline fuel usage as a source of isobutene and formaldehyde. Both these reactive species can lead to increased oxidant and PAN formation. The strong diurnal profiles of PANs are consistent with regional clearing of the Mexico City air basin on a daily basis. Estimates are given using a simple box model calculation for a number of key primary and secondary pollutant emissions From this megacity on an annual basis. These calculations indicate that megacities can be important sources of both primary and secondary pollutants: and that PANs produced in megacity environments are likely to contribute strongly to regional scale ozone and aerosol productions during long range transport. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. RP Gaffney, JS (reprint author), Argonne Natl Lab, Div Environm Res, Bldg 203-ER,9700 S Cass Ave, Argonne, IL 60439 USA. NR 27 TC 46 Z9 46 U1 3 U2 11 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD DEC PY 1999 VL 33 IS 30 BP 5003 EP 5012 DI 10.1016/S1352-2310(99)00263-0 PG 10 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 263YX UT WOS:000084153800004 ER PT J AU Mohandas, N Gascard, P AF Mohandas, N Gascard, P TI What do mouse gene knockouts tell us about the structure and function of the red cell membrane? SO BEST PRACTICE & RESEARCH CLINICAL HAEMATOLOGY LA English DT Article DE red cell; cytoskeletal proteins; knockout mice; haemolytic anaemias; membrane structure ID HUMAN-ERYTHROCYTE-MEMBRANE; INHERITED HEMOLYTIC-ANEMIAS; SPECTRIN-ACTIN-BINDING; PROTEIN 4.1; GLYCOPHORIN-A; BLOOD-CELLS; HEREDITARY ELLIPTOCYTOSIS; CYTOSKELETAL PROTEIN; TARGETED DISRUPTION; ROTATIONAL MOBILITY AB Recent development of knockout mice with targeted deletion of specific genes encoding various red cell membrane proteins has added valuable armamentarium to red cell membrane structure-function studies. In this chapter we will summarize the various recent developments regarding the structure and function of the red cell membrane derived from studies using knockout mice. In addition to being expressed in red cells, all major red cell membrane proteins are also expressed in cells of various tissues. The potential use of knockout mice to decipher the biological functions of red cell membrane proteins in non-erythroid cells is also explored. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP Mohandas, N (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. NR 80 TC 10 Z9 10 U1 0 U2 0 PU BAILLIERE TINDALL PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 1521-6926 J9 BEST PRACT RES CL HA JI Best Pract. Res. Clin. Haematol. PD DEC PY 1999 VL 12 IS 4 BP 605 EP 620 DI 10.1053/beha.1999.0044 PG 16 WC Hematology SC Hematology GA 326VV UT WOS:000087758500002 PM 10895255 ER PT J AU Parsons, SF Spring, FA Chasis, JA Anstee, DJ AF Parsons, SF Spring, FA Chasis, JA Anstee, DJ TI Erythroid cell adhesion molecules Lutheran and LW in health and disease SO BEST PRACTICE & RESEARCH CLINICAL HAEMATOLOGY LA English DT Review DE Lutheran; LW; blood groups; laminin; integrins; cell adhesion; erythropoiesis; sickle cell disease ID BLOOD-GROUP ANTIGENS; INTEGRIN-ASSOCIATED PROTEIN; LAMININ ALPHA-5 CHAIN; MARROW STROMAL CELLS; IMMUNOGLOBULIN SUPERFAMILY; ENDOTHELIAL-CELLS; BONE-MARROW; HEMATOPOIETIC PROGENITORS; SURFACE GLYCOPROTEIN; SICKLE RETICULOCYTES AB The Lutheran and LW glycoproteins are blood group-active proteins found at the surface of human red cells. The Lutheran glycoprotein (Lu gp) is a member of the immunoglobulin superfamily (IgSF) that binds the extracellular matrix protein laminin, in particular, laminin isoforms containing the alpha 5 subunit. The LW glycoprotein (LW gp), also an IgSF member, has substantial sequence homology with the family of intercellular adhesion molecules (ICAMs). LW gp binds the integrin very late antigen-4 (VLA-4, alpha(4)beta(1)) and alpha(v)-containing integrins. Studies on the expression of LW and Lu gps during erythropoiesis utilizing in vitro cultures of haemopoietic progenitor cells have shown that LW gp expression precedes that of Lu gp. These observations have led to the suggestion that LW gp on erythroblasts may interact with VLA-4 on macrophages to stabilize erythroblastic islands in normal bone marrow and that Lu gp may facilitate trafficking of more mature erythroid cells to the sinusoidal endothelium where alpha 5-containing laminins are known to be expressed. Levels of Lu gp and LW gp expression on sickle red cells are greater than on normal red cells and sickle red cells adhere to alpha 5-containing laminins. These data suggest that the Lu and LW molecules may contribute to the vaso-occlusive events associated with episodes of acute pain in sickle cell disease. C1 Bristol Inst Transfus Sci, Bristol BS10 5ND, Avon, England. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP Parsons, SF (reprint author), Bristol Inst Transfus Sci, Southmead Rd, Bristol BS10 5ND, Avon, England. NR 109 TC 35 Z9 37 U1 0 U2 0 PU BAILLIERE TINDALL PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 1521-6926 J9 BEST PRACT RES CL HA JI Best Pract. Res. Clin. Haematol. PD DEC PY 1999 VL 12 IS 4 BP 729 EP 745 DI 10.1053/beha.1999.0050 PG 17 WC Hematology SC Hematology GA 326VV UT WOS:000087758500008 PM 10895261 ER PT J AU Cariaso, M Folta, P Wagner, M Kuczmarski, T Lennon, G AF Cariaso, M Folta, P Wagner, M Kuczmarski, T Lennon, G TI IMAGEne I: clustering and ranking of IMAGE. cDNA clones corresponding to known genes SO BIOINFORMATICS LA English DT Article ID EXPRESSED SEQUENCE TAGS AB Motivation: To enhance the usefulness of the I.M.A.G.E. Consortium (Lennon et al., 1996 Genomics, 33, 151-152) cDNA clone collection by directed analysis and organization of their associated Expressed Sequence Tags (ESTs), thus enabling effective mining of the immense amounts of public cDNA information. Results: This paper introduces the IMAGEne suite of tools, which clusters ESTs around known genes, then ranks each clone within a cluster IMAGEne filters data from known gene sequence databases and the GenBank's EST database (Boguski and Shuler, 1995, Nature Genet., 10, 369-371). It applies biological criteria in connection with judicious use of the BLAST (Altschul et al., 1990, J. Mol. Biol., 215), FASTA (Pearson and Lipman, 1988, Proc. Natl Acad. Sci. USA, 85, 2444-2448; Pearson, 1990 Methods Enzymol., 183, 63-98; Gusfield, 1997, Algorithms on Strings, Trees, and Sequences, Cambridge University Press), and SIM (Huang et al., 1990 Comput. Appl. Biosci., 6, 373-381) tools to form known gene clusters. It then applies criteria derived from experienced biologists to select the best representative I.M.A.G.E. clone for a gene. The tool provides an intuitive Java interface for query and display of the gene and its associated clones, thus directing researchers in selecting a clone that will best enhance their research. An important product is a listing of clones that best represent all known genes. The listing will be used for re-arraying clones into minimally redundant Master Arrays. Both the listings and Master Arrays will be made available to the public, which will be a valuable resource to the genomic community in furthering discovery in the area of gene function. C1 Lawrence Livermore Natl Lab, Biol & Biotechnol Program, Livermore, CA 94550 USA. RP Folta, P (reprint author), Lawrence Livermore Natl Lab, Biol & Biotechnol Program, Livermore, CA 94550 USA. EM folta2@llnl.gov NR 11 TC 4 Z9 5 U1 0 U2 1 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 1367-4803 EI 1460-2059 J9 BIOINFORMATICS JI Bioinformatics PD DEC PY 1999 VL 15 IS 12 BP 965 EP 973 DI 10.1093/bioinformatics/15.12.965 PG 9 WC Biochemical Research Methods; Biotechnology & Applied Microbiology; Computer Science, Interdisciplinary Applications; Mathematical & Computational Biology; Statistics & Probability SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Computer Science; Mathematical & Computational Biology; Mathematics GA 293DJ UT WOS:000085836000003 PM 10745985 ER PT J AU Singh, AK Flounders, AW Volponi, JV Ashley, CS Wally, K Schoeniger, JS AF Singh, AK Flounders, AW Volponi, JV Ashley, CS Wally, K Schoeniger, JS TI Development of sensors for direct detection of organophosphates. Part I: immobilization, characterization and stabilization of acetylcholinesterase and organophosphate hydrolase on silica supports SO BIOSENSORS & BIOELECTRONICS LA English DT Article DE organophosphate; sensor; organophosphate hydrolase; acetylcholinesterase; enzyme; immobilization; sol-gel; FET; ISFET; pHFET; EnFET; AChE; OPH ID PSEUDOMONAS-DIMINUTA; PROTEIN; ANTIBODIES; SURFACES; PHOSPHOTRIESTERASE; ENCAPSULATION; AGENTS; GLASS AB Biosensors for organophosphates in solution may be constructed by monitoring the activity of acetylcholinesterase (AChE) or organophosphate hydrolase (OPH) immobilized to a variety of microsensor platforms. The area available for enzyme immobilization is small (<1 mm(2)) for microsensors. In order to construct microsensors with increased surface area for enzyme immobilization, we used a sol-gel process to create highly porous and stable silica matrices. Surface porosity of sol-gel coated surfaces was characterized using scanning electron microscopy; pore structure was found to be very similar to that of commercially available porous silica supports. Based upon this analysis, porous and non-porous silica beads were used as model substrates of sol-gel coated and uncoated sensor surfaces. Two different covalent chemistries were used to immobilize AChE and OPH to these porous and non-porous silica beads. The first chemistry used amine-silanization of silica followed by enzyme attachment using the homobifunctional linker glutaraldehyde. The second chemistry used sulfhydryl-silanization followed by enzyme attachment using the heterobifunctional linker N-gamma-maleimidobutyryloxy succinimide ester (GMBS). Surfaces were characterized in terms of total enzyme immobilized, total and specific enzyme activity, and long term stability of enzyme activity. Amine derivitization followed by glutaraldehyde linking yielded supports with greater amounts of immobilized enzyme and activity. Use of porous supports not only yielded greater amounts of immobilized enzyme and activity, but also significantly improved long term stability of enzyme activity. Enzyme was also immobilized to sol-gel coated glass slides. The mass of immobilized enzyme increased linearly with thickness of coating. However, immobilized enzyme activity saturated at a porous silica thickness of approximately 800 nm. Published by Elsevier Science S.A. C1 Sandia Natl Labs, Chem & Radiat Detect Lab, Livermore, CA 94551 USA. RP Schoeniger, JS (reprint author), Sandia Natl Labs, Chem & Radiat Detect Lab, POB 969,MS 9671, Livermore, CA 94551 USA. NR 23 TC 114 Z9 129 U1 2 U2 27 PU ELSEVIER ADVANCED TECHNOLOGY PI OXFORD PA OXFORD FULFILLMENT CENTRE THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0956-5663 J9 BIOSENS BIOELECTRON JI Biosens. Bioelectron. PD DEC PY 1999 VL 14 IS 8-9 BP 703 EP 713 DI 10.1016/S0956-5663(99)00044-5 PG 11 WC Biophysics; Biotechnology & Applied Microbiology; Chemistry, Analytical; Electrochemistry; Nanoscience & Nanotechnology SC Biophysics; Biotechnology & Applied Microbiology; Chemistry; Electrochemistry; Science & Technology - Other Topics GA 265UU UT WOS:000084264800006 PM 10641290 ER PT J AU Flounders, AW Singh, AK Volponi, JV Carichner, SC Wally, K Simonian, AS Wild, JR Schoeniger, JS AF Flounders, AW Singh, AK Volponi, JV Carichner, SC Wally, K Simonian, AS Wild, JR Schoeniger, JS TI Development of sensors for direct detection of organophosphates. Part II: sol-gel modified field effect transistor with immobilized organophosphate hydrolase SO BIOSENSORS & BIOELECTRONICS LA English DT Article DE organophosphate; sensor; organophosphate hydrolase; acetylcholinesterase; enzyme; immobilization; sol-gel; field effect transistors; ISFET; pHFET; EnFET; acetylcholinesterase; organophosphate hydrolase ID STATIC ENZYME SENSOR; PSEUDOMONAS-DIMINUTA; NERVE AGENTS; PHOSPHOTRIESTERASE; PESTICIDES; BIOSENSOR; CHOLINESTERASE; NEUROTOXINS; EXPRESSION; INHIBITION AB pH-sensitive field effect transistors (FET) were modified with organophosphate hydrolase (OPH) and used for direct detection of organophosphate compounds. OPH is the organophosphate degrading gene product isolated from Pseudomonas diminuta. OPH was selected as an alternative to acetylcholinesterase, which requires inhibition mode sensor operation, enzyme regeneration before reuse, long sample incubation times, and a constant source of acetylcholine substrate. OPH was covalently immobilized directly to the exposed silicon nitride gate insulator of the FET. Alternatively, silica microspheres of 20 or 200 nm were formed via a base catalyzed sol-gel process acid were dip-coated onto the gate surface; enzyme was then covalently immobilized to this modified surface. All sensors were tested with paraoxon and displayed rapid response (<10 s), with a detection limit of approximately 1 x 10(-6) molar. The 200 nm sol-gel gale modification enhanced the signal of enzyme-modified devices without effecting device pH sensitivity. Sensors were stored at 4 degrees C in buffer and tested multiple times. Devices coated with 200 nm silica microspheres maintained significant enzymatic activity over a period of 10 weeks while uncoated devices lost all enzyme activity during the same period. The 20 nm sol-gel modification did not enhance device response or enzyme stability. Successful reuse of sensor chips was demonstrated after stripping inactive enzyme with an RF oxygen plasma system and reimmobilizing active enzyme. Published by Elsevier Science S.A. C1 Sandia Natl Labs, Chem & Radiat Detect Lab, Livermore, CA 94551 USA. Texas A&M Univ, Dept Biochem & Biophys, College Stn, TX 77843 USA. RP Flounders, AW (reprint author), Sandia Natl Labs, Chem & Radiat Detect Lab, POB 969,MS 9671, Livermore, CA 94551 USA. NR 54 TC 46 Z9 50 U1 4 U2 17 PU ELSEVIER ADVANCED TECHNOLOGY PI OXFORD PA OXFORD FULFILLMENT CENTRE THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0956-5663 J9 BIOSENS BIOELECTRON JI Biosens. Bioelectron. PD DEC PY 1999 VL 14 IS 8-9 BP 715 EP 722 DI 10.1016/S0956-5663(99)00045-7 PG 8 WC Biophysics; Biotechnology & Applied Microbiology; Chemistry, Analytical; Electrochemistry; Nanoscience & Nanotechnology SC Biophysics; Biotechnology & Applied Microbiology; Chemistry; Electrochemistry; Science & Technology - Other Topics GA 265UU UT WOS:000084264800007 ER PT J AU Nasarabadi, S Milanovich, F Richards, J Belgrader, P AF Nasarabadi, S Milanovich, F Richards, J Belgrader, P TI Simultaneous detection of TaqMan((R)) probes containing Fam and Tamra reporter fluorophores SO BIOTECHNIQUES LA English DT Article ID PCR C1 Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94550 USA. RP Nasarabadi, S (reprint author), Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, L-452,7000 East Ave, Livermore, CA 94550 USA. NR 11 TC 20 Z9 21 U1 1 U2 2 PU EATON PUBLISHING CO PI NATICK PA 154 E. CENTRAL ST, NATICK, MA 01760 USA SN 0736-6205 J9 BIOTECHNIQUES JI Biotechniques PD DEC PY 1999 VL 27 IS 6 BP 1116 EP + PG 2 WC Biochemical Research Methods; Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 263YN UT WOS:000084153000005 PM 10631486 ER PT J AU Praissman, JL Sutherland, JC AF Praissman, JL Sutherland, JC TI Laboratory voice data entry system SO BIOTECHNIQUES LA English DT Article AB We have assembled a system using a personal computer workstation equipped with standard office software, an audio system, speech recognition software and an inexpensive radio-based wireless microphone that permits laboratory workers to enter. or modify, data while performing other work. Speech recognition permits users to enter data while their hands are holding equipment or they ale otherwise unable to operate a keyboard. The wireless microphone allows unencumbered movement around the laboratory without a "tether" that might interfere with equipment or experimental procedures. To evaluate the potential of voice data entry in a laboratory environment, we developed a prototype relational database that records the disposal of radionuclides and/or hazardous chemicals. Current regulations in our laboratory require that each such item being discarded must be inventoried and documents must be prepared that summarize the contents of each container used for disposal. using voice commands, the user enters items into the database as each is discarded. Subsequently, the program prepares the required documentation. C1 Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Sutherland, JC (reprint author), Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. NR 2 TC 1 Z9 1 U1 0 U2 0 PU EATON PUBLISHING CO PI NATICK PA 154 E. CENTRAL ST, NATICK, MA 01760 USA SN 0736-6205 J9 BIOTECHNIQUES JI Biotechniques PD DEC PY 1999 VL 27 IS 6 BP 1202 EP + PG 5 WC Biochemical Research Methods; Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 263YN UT WOS:000084153000018 PM 10631499 ER PT J AU Lyness, JN Joe, S AF Lyness, JN Joe, S TI A constructive approach to lattice rule canonical forms SO BIT LA English DT Article DE constructing canonical forms; lattice rules; Sylow p-decomposition AB The rank and invariants of a general lattice rule are conventionally defined in terms of the group-theoretic properties of the rule. Here we give a constructive definition of the rank and invariants using integer matrices. This underpins a nonabstract algorithm set in matrix algebra for obtaining the Sylow precomposition of a lattice rule. This approach is particularly useful when it is not known whether the form in which the lattice rule is specified is canonical or even repetitive. A new set of necessary and sufficient conditions for recognizing a canonical form is given. AMS subject classification: 65D30. C1 Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. Univ Waikato, Dept Math, Hamilton, New Zealand. OI Joe, Stephen/0000-0002-7652-9205 NR 9 TC 1 Z9 1 U1 0 U2 0 PU SWETS ZEITLINGER PUBLISHERS PI LISSE PA P O BOX 825, 2160 SZ LISSE, NETHERLANDS SN 0006-3835 J9 BIT JI Bit PD DEC PY 1999 VL 39 IS 4 BP 701 EP 715 DI 10.1023/A:1022391207786 PG 15 WC Computer Science, Software Engineering; Mathematics, Applied SC Computer Science; Mathematics GA 273YC UT WOS:000084736100006 ER PT J AU Kinney, JH AF Kinney, JH TI Untitled SO BONE LA English DT Letter ID TRABECULAR BONE; CONNECTIVITY C1 Univ Calif Lawrence Livermore Natl Lab, Dept Chem & Mat Sci, Livermore, CA 94550 USA. RP Kinney, JH (reprint author), Univ Calif Lawrence Livermore Natl Lab, Dept Chem & Mat Sci, Livermore, CA 94550 USA. NR 7 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 8756-3282 J9 BONE JI Bone PD DEC PY 1999 VL 25 IS 6 BP 741 EP 741 DI 10.1016/S8756-3282(99)00230-6 PG 1 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA 260AF UT WOS:000083925600015 PM 10593420 ER PT J AU Barnett, TP Hasselmann, K Chelliah, M Delworth, T Hegerl, G Jones, P Rasmusson, E Roeckner, E Ropelewski, C Santer, B Tett, S AF Barnett, TP Hasselmann, K Chelliah, M Delworth, T Hegerl, G Jones, P Rasmusson, E Roeckner, E Ropelewski, C Santer, B Tett, S TI Detection and attribution of recent climate change: A status report SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID GENERAL-CIRCULATION MODEL; SURFACE-TEMPERATURE; GREENHOUSE-GAS; FINGERPRINT METHOD; ATMOSPHERE; SIGNALS; VARIABILITY; TRENDS; SIMULATION; AEROSOL AB This paper addresses the question of where we now stand with respect to detection and attribution of an anthropogenic climate signal. Our ability to estimate natural climate variability, against which claims of anthropogenic signal detection must be made, is reviewed. The current situation suggests control runs of global climate models may give the best estimates of natural variability on a global basis, estimates that appear to be accurate to within a factor of 2 or 3 at multidecadal timescales used in detection work. Present uncertainties in both observations and model-simulated anthropogenic signals in near-surface air temperature are estimated. The uncertainty in model simulated signals is, in places, as large as the signal to be detected. Two different, but complementary, approaches to detection and attribution are discussed in the context of these uncertainties. Applying one of the detection strategies, it is found that the change in near-surface, June through August air temperature field over the last 50 years is generally different at a significance level of 5% from that expected from model-based estimates of natural variability. Greenhouse gases alone cannot explain the observed change. Two of four climate models forced by greenhouse gases and direct sulfate aerosols produce results consistent with the current climate change observations, while the consistency of the other two depends on which model's anthropogenic fingerprints are used. A recent integration with additional anthropogenic forcings (the indirect effects of sulfate aerosols and tropospheric ozone) and more complete tropospheric chemistry produced results whose signal amplitude and pattern were consistent with current observations, provided the model's fingerprint is used and detection carried out over only the last 30 years of annually averaged data. This single integration currently cannot be corroborated and provides no opportunity to estimate the uncertainties inherent in the results, uncertainties that are thought to be large and poorly known. These results illustrate the current large uncertainty in the magnitude and spatial pattern of the direct and indirect sulfate forcing and climate response. They also show detection statements depend on model-specific fingerprints, time period, and seasonal character of the signal, dependencies that have not been well explored. Most, but not all, results suggest that recent changes in global climate inferred from surface air temperature are likely not due solely to natural causes. At present it is not possible to make a very confident statement about the relative contributions of specific natural and anthropogenic forcings to observed climate change. One of the main reasons is that fully realistic simulations of climate change due to the combined effects of all anthropogenic and natural forcings mechanisms have yet to be computed. A List of recommendations for reducing some of the uncertainties that currently hamper detection and attribution studies is presented. C1 Univ Calif San Diego, Scripps Inst Oceanog, Div Climate Res, Dept 0224, La Jolla, CA 92093 USA. Max Planck Inst Meteorol, Hamburg, Germany. Natl Ctr Environm Predict, Washington, DC USA. Geophys Fluid Dynam Lab, Princeton, NJ USA. Univ Washington, JISAO, Seattle, WA 98195 USA. Univ E Anglia, Norwich NR4 7TJ, Norfolk, England. Univ Maryland, College Pk, MD 20742 USA. Lamont Doherty Earth Observ, Int Res Inst, Palisades, NY 10964 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. Meteorol Off, Hadley Ctr Climate Predict & Res, Bracknell RB12 2SZ, Berks, England. RP Barnett, TP (reprint author), Univ Calif San Diego, Scripps Inst Oceanog, Div Climate Res, Dept 0224, La Jolla, CA 92093 USA. RI Jones, Philip/C-8718-2009; Santer, Benjamin/F-9781-2011; Tett, Simon/B-1504-2013; Delworth, Thomas/C-5191-2014 OI Jones, Philip/0000-0001-5032-5493; Tett, Simon/0000-0001-7526-560X; NR 68 TC 113 Z9 115 U1 1 U2 21 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD DEC PY 1999 VL 80 IS 12 BP 2631 EP 2659 DI 10.1175/1520-0477(1999)080<2631:DAAORC>2.0.CO;2 PG 29 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 261PA UT WOS:000084016500003 ER PT J AU Hartzell, S Harmsen, S Frankel, A Larsen, S AF Hartzell, S Harmsen, S Frankel, A Larsen, S TI Calculation of broadband time histories of ground motion: Comparison of methods and validation using strong-ground motion from the 1994 Northridge earthquake SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID EMPIRICAL GREENS-FUNCTIONS; LOS-ANGELES BASIN; NONLINEAR SOIL RESPONSE; STOCHASTIC FAULT MODEL; SAN-FERNANDO VALLEY; SEISMIC-WAVES; SITE-RESPONSE; FINITE-FAULT; S-WAVE; CALIFORNIA AB This article compares techniques for calculating broadband time histories of ground motion in the near field of a finite fault by comparing synthetics with the strong-motion data set for the 1994 Northridge earthquake. Based on this comparison, a preferred methodology is presented. Ground-motion-simulation techniques are divided into two general methods: kinematic- and composite-fault models. Green's functions of three types are evaluated: stochastic, empirical, and theoretical. A hybrid scheme is found to give the best fit to the Northridge data. Low frequencies (< 1 Hz) are calculated using a kinematic-fault model and a 3D finite-difference code to propagate energy through a realistic 3D velocity structure. High frequencies (> 1 Hz) are calculated using a composite-fault model with a fractal subevent size distribution and stochastic, bandlimited, white-noise Green's functions, At frequencies below 1 Hz, theoretical elastic-wave-propagation synthetics introduce proper seismic-phase arrivals of body waves and surface waves. The 3D velocity structure more accurately reproduces record durations for the deep sedimentary basin structures found in the Los Angeles region. At frequencies above I Hz, scattering effects become important and wave propagation is more accurately represented by stochastic Green's functions. A fractal subevent size distribution for the composite fault model ensures an omega(-2) spectral shape over the entire frequency band considered (0.1-20 Hz). C1 US Geol Survey, Denver Fed Ctr, Denver, CO 80225 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Hartzell, S (reprint author), US Geol Survey, Denver Fed Ctr, Box 25046 MS 966, Denver, CO 80225 USA. NR 92 TC 107 Z9 113 U1 1 U2 14 PU SEISMOLOGICAL SOC AMER PI EL CERRITO PA PLAZA PROFESSIONAL BLDG, SUITE 201, EL CERRITO, CA 94530 USA SN 0037-1106 J9 B SEISMOL SOC AM JI Bull. Seismol. Soc. Amer. PD DEC PY 1999 VL 89 IS 6 BP 1484 EP 1504 PG 21 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 276PP UT WOS:000084886800008 ER PT J AU Phillips, WS Pearson, DC Yang, XN Stump, BW AF Phillips, WS Pearson, DC Yang, XN Stump, BW TI Aftershocks of an explosively induced mine collapse at White Pine, Michigan SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID SOURCE PARAMETERS; SEISMIC EVENTS; MINING DISTRICT; UNITED-STATES; STRESS; MECHANISM; EARTHQUAKES; SPECTRA; TREMORS; PLANES AB We recorded an explosively induced, 320-m-deep mine collapse and subsequent aftershocks at White Pine, Michigan, using an array of 12 seismic stations, sited within 1 km of surface ground zero. The collapse, which followed the rubblizing of a 2 x 10(4) m(2) panel of a room-and-pillar copper mine, was induced to facilitate leaching operations. The explosions produced little seismic energy; however, fracturing and collapse stages produced large signals that were observed at distances up to 900 km, yielding a magnitude (m(bLg)) of 2.8. Previous work showed the initial collapse to be an expanding seismic source, interpreted as an opening tensile crack, opposite to the implosional character most often observed for natural mine collapses (Yang et al., 1998). We counted over 4000 aftershocks; their occurrence rate followed the modified Omori law: rate = 560 (time - 0.01)(-1.3), with time in hours. Based on P-wave polarities, we identified events of shear-slip, implosional, and tensile character in the aftershock sequence. For shear-slip events, we found stress drops of 1 bar or less, seismic moments of 10(15)-10(17) dyne cm, (M-w - 0.8-0.5) and source radii of 10-50 m. Corner frequencies for implosional events were relatively low, an indication that the collapsed cavity played a role in the source process. This caused implosional events to separate from other events in source parameter plots, providing a technique for classifying events of unknown type. We obtained locations of 135 aftershocks using P- and S-wave data. The aftershock zone was less than 100-m thick, situated just above and along the western, mined edge of the collapsed mine panel. Implosional events occurred at the bottom of the active volume, while shear-slip events were distributed throughout. Shear-slip focal mechanisms indicated thrusting along north-striking planes, consistent with the high, east-west regional compressive stress, coupled with a local decrease in vertical stress. The inferred deficit of vertical stress above the western panel edge following collapse indicated that overburden load shifted preferentially to the surrounding, unmined areas, consistent with lower-than-predicted stresses measured in the first row of intact pillars. C1 Los Alamos Natl Lab, Seism Res Ctr, Los Alamos, NM 87545 USA. So Methodist Univ, Dept Geol Sci, Dallas, TX 75275 USA. RP Los Alamos Natl Lab, Seism Res Ctr, POB 1663, Los Alamos, NM 87545 USA. NR 33 TC 6 Z9 6 U1 0 U2 1 PU SEISMOLOGICAL SOC AMER PI ALBANY PA 400 EVELYN AVE, SUITE 201, ALBANY, CA 94706-1375 USA SN 0037-1106 EI 1943-3573 J9 B SEISMOL SOC AM JI Bull. Seismol. Soc. Amer. PD DEC PY 1999 VL 89 IS 6 BP 1575 EP 1590 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 276PP UT WOS:000084886800014 ER PT J AU Pfromm, PH Tsai, SP Henry, MP AF Pfromm, PH Tsai, SP Henry, MP TI Electrodialysis for bleach effluent recycling in kraft pulp production: Simultaneous control of chloride and other non-process elements SO CANADIAN JOURNAL OF CHEMICAL ENGINEERING LA English DT Article DE electrodialysis; bleach effluent; bleached kraft pulp; chloride; non-process elements ID RECOVERY; MILL; CLOSURE; CYCLE AB In the United States, more than 50 million tons of kraft pulp are produced per year. A strong effort by kraft pulp producers has been under way for several years to reduce water use. The in-process recycling of the acidic bleach effluent carrying metals, transition metals, calcium, and often large amounts of chloride is still a significant challenge. The simultaneous selective removal of chloride, and detrimental cations from the acidic bleach effluent of bleached kraft pulp mills by electrodialysis was investigated. The laboratory results with actual effluents show that very good removal levels can be achieved in an economical process. The chloride removal From acidic bleach effluent will aid significantly in keeping chloride levels acceptable in the recovery cycle. C1 Inst Paper Sci & Technol, Atlanta, GA 30318 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP Pfromm, PH (reprint author), Inst Paper Sci & Technol, 575 14th St NW, Atlanta, GA 30318 USA. RI Pfromm, Peter/I-3526-2013 OI Pfromm, Peter/0000-0003-4869-9503 NR 31 TC 3 Z9 3 U1 0 U2 8 PU CANADIAN SOC CHEMICAL ENGINEERING PI OTTAWA PA 130 SLATER ST, STE 550, OTTAWA, ONTARIO K1P 6E2, CANADA SN 0008-4034 J9 CAN J CHEM ENG JI Can. J. Chem. Eng. PD DEC PY 1999 VL 77 IS 6 BP 1231 EP 1238 PG 8 WC Engineering, Chemical SC Engineering GA 283EC UT WOS:000085262300021 ER PT J AU Peacor, DR Rouse, RC Essene, EJ Lauf, RJ AF Peacor, DR Rouse, RC Essene, EJ Lauf, RJ TI Coskrenite-(Ce), (Ce,Nd,La)(2)(SO4)(2)(C2O4)center dot 8H(2)O, a new rare-earth oxalate mineral from Alum Cave Bluff, Tennessee: Characterization and crystal structure SO CANADIAN MINERALOGIST LA English DT Article DE coskrenite-(Ce); new mineral species; rare-earth oxalate; X-ray data; crystal-structure determination; Alum Cave Bluff; Tennessee ID VALENCE AB The new mineral species coskrenite-(Ce) [(Ce,Nd,La)(2)(SO4)(2)(C2O4). 8H(2)O] occurs as transparent, pink- to cream-colored clusters of tabular crystals 0.1 to 1.0 mm across embedded within, or in cavities in, epsomite and "hair salts" (principally apjohnite) at Alum Cave Bluff, Great Smoky Mountains, Tennessee. A complex suite of sulfates occurs in the soil or on the ceiling of a rock shelter, as a result of weathering of pyritic phyllite and evaporation of the resulting solutions. Coskrenite-(Ce) is closely associated with two other new minerals, levinsonite-(Y) [(Y,Nd,Ce)Al(SO3)(2)(C2O4). 12H(2)O] and zugshunstite-(Ce) [(Ce,Nd,La)Al(SO4)(2)(C2O4). 12H(2)O]. They are the first natural examples of rare-earth oxalate salts. Coskrenite-(Ce) is triclinic, space group P1, a 6.007(1), b 8.368(2), c 9.189(2) Angstrom, a 99.90(2), beta 105.55 (2), gamma 107.71(2)degrees V407.4(2) Angstrom(3), and Z = 1. The basic structural unit is a four-membered ring of two REE(O,H2O)(9) polyhedra and two SO4 tetrahedra, each sulfate tetrahedron sharing two of its vertices with two REE polyhedra. These rings are linked into chains, and adjacent chains are linked by oxalate groups and hydrogen bonds into sheets oriented parallel to {001}. Adjacent sheets are weakly bonded together through hydrogen bonds. The REE site is nine-coordinated by a distorted monocapped square antiprism of five O and four H2O, with an average REE-O distance of 2.518 Angstrom. The strongest lines in the powder-diffraction pattern [d in Angstrom(I)(hkl)] are: 5.48(100)(110), 8.52(70)(001), 6.72(60)(011), 3.84(60)(020,110), 4.26(50)(002,012), 3.35(40)(022), and 2.744(40)(122,212,130,220). Coskrenite-(Ce) is biaxial negative, alpha = 1.544(4), beta = 1.578(4), gamma = 1.602(4), 2V(obs.) = 65(10)degrees. 2V(calc.)= 69(3)degrees dispersion medium (r > v), and Z' c = 21 degrees (in plane of cleavage). The mineral is named after its discoverer, T. Dennis Coskren. C1 Univ Michigan, Dept Geol Sci, Ann Arbor, MI 48109 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Peacor, DR (reprint author), Univ Michigan, Dept Geol Sci, 1006 CC Little Bldg, Ann Arbor, MI 48109 USA. EM drpeacor@umich.edu NR 21 TC 9 Z9 9 U1 0 U2 0 PU MINERALOGICAL ASSOC CANADA PI QUEBEC PA 490, RUE DE LA COURONNE, QUEBEC, QC G1K 9A9, CANADA SN 0008-4476 EI 1499-1276 J9 CAN MINERAL JI Can. Mineral. PD DEC PY 1999 VL 37 BP 1453 EP 1462 PN 6 PG 10 WC Mineralogy SC Mineralogy GA 287JM UT WOS:000085502800012 ER PT J AU Sugama, T Weber, L Brothers, LE AF Sugama, T Weber, L Brothers, LE TI Resistance of sodium polyphosphate-modified fly ash/calcium aluminate blend cements to hot H2SO4 solution SO CEMENT AND CONCRETE RESEARCH LA English DT Article DE calcium phosphate cement; sulfate attack; fly ash; calcium aluminate cement; sodium polyphosphate; geothermal cement ID HYDROXYAPATITE AB Sodium polyphosphate-modified Class F fly ash/calcium aluminate blend (SFCB) cements were prepared at room temperature and their resistance to hot acid erosion was evaluated by submerging them in H2SO4, solution (pH 1.6) at 90 degrees C. Sodium polyphosphate preferentially reacted with calcium aluminate cement (CAC) to form amorphous Ca(HPO4). xH(2)O and Al2O3. xH(2)O gel, rather than fly ash. These amorphous reaction products, which bound the partially reacted and unreacted CAC and fly ash particles into a coherent mass, were responsible for strengthening and densifying the SFCB specimens at room temperature, playing an essential role in mitigating their acid erosion. In these cements, the extent of acid erosion depended primarily on the ratio of fly ash/CAC; namely, those with a higher ratio underwent a severe erosion. This effect was due to the formation of a porous structure, which allowed acid to permeate the cement easily, diminishing the protective activity of Ca(HPO4). xH(2)O and Al2O3. xH(2)O gel against H2SO4. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Brookhaven Natl Lab, Dept Appl Sci, Div Mat & Chem Sci, Upton, NY 11973 USA. Unocal Corp, Sugar Land, TX 77478 USA. Halliburton Energy Serv, Duncan, OK 73536 USA. RP Sugama, T (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Div Mat & Chem Sci, Upton, NY 11973 USA. RI Chen, Wei/A-5694-2010 NR 11 TC 6 Z9 6 U1 1 U2 8 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0008-8846 J9 CEMENT CONCRETE RES JI Cem. Concr. Res. PD DEC PY 1999 VL 29 IS 12 BP 1969 EP 1976 DI 10.1016/S0008-8846(99)00220-3 PG 8 WC Construction & Building Technology; Materials Science, Multidisciplinary SC Construction & Building Technology; Materials Science GA 275NH UT WOS:000084825900013 ER PT J AU Pelissier, H Rodriguez, J Vollhardt, KPC AF Pelissier, H Rodriguez, J Vollhardt, KPC TI Cobalt-mediated [2+2+2] cycloadditions of pyrimidine derivatives to alkynes SO CHEMISTRY-A EUROPEAN JOURNAL LA English DT Article DE alkynes; cobalt; cyclo-oligomerizations; heterocyles ID NUCLEAR MAGNETIC-RESONANCE; NUCLEOSIDE ANALOGS; BOND; CONFORMATIONS; SPECTROSCOPY; THIOPHENE; CHEMISTRY; CLEAVAGE; COMPLEX; PRODUCT AB The scope and limitations of the cobalt-mediated [2+2+2] cycloaddition of pyrimidine derivatives to alkynes has been investigated. The 5,6-double bond of these heterocyclic nuclei has been found to participate in an entirely intermolecular fashion to generate chemo- and stereoselectively novel, fused and substituted 5,6-dihydropyrimidine cobalt complexes, which upon oxidative demetallation liberate the corresponding new heterocyclic ligand. On the other hand, 1-alkynyl pyrimidines have been found to be suitable partners in the cocyclization with disubstituted alkynes, such as bis(trimethylsilyl)acetylene (BTMSA) or dimethyl 2-butyn-1,4-dioate (DMAD), to allow the direct preparation of hitherto unknown dihydropyrido[3,2-ij]quinazoline cobalt complexes. Effects of the substitution on the pyrimidine nucleus, the cocyclization partner, the complex auxiliary, and the reaction conditions were examined, and in some cases competing pathways that lead to [CpCo(cyclobutadienes) ], cyclopentadienone complexes, and compounds that arise from a C-H activation-type reaction were observed. C1 Ctr St Jerome, Lab ReSo React & Synthese Organ, CNRS, UMR 6516, F-13397 Marseille, France. Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. CNRS, Organ Synth Lab, ESA 6009, F-13397 Marseille 20, France. RP Rodriguez, J (reprint author), Ctr St Jerome, Lab ReSo React & Synthese Organ, CNRS, UMR 6516, Boite D12, F-13397 Marseille, France. NR 71 TC 28 Z9 28 U1 1 U2 8 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0947-6539 J9 CHEM-EUR J JI Chem.-Eur. J. PD DEC PY 1999 VL 5 IS 12 BP 3549 EP 3561 DI 10.1002/(SICI)1521-3765(19991203)5:12<3549::AID-CHEM3549>3.0.CO;2-V PG 13 WC Chemistry, Multidisciplinary SC Chemistry GA 264CU UT WOS:000084163400016 ER PT J AU Woodward, PM Cox, DE Vogt, T Rao, CNR Cheetham, AK AF Woodward, PM Cox, DE Vogt, T Rao, CNR Cheetham, AK TI Effect of compositional fluctuations on the phase transitions in (Nd1/2Sr1/2)MnO3 SO CHEMISTRY OF MATERIALS LA English DT Article ID ANTIFERROMAGNETIC METALLIC STATE; CHARGE-ORDERED STRIPES; COLOSSAL MAGNETORESISTANCE; PEROVSKITE MANGANITES; ELECTRONIC MODELS; SEPARATION; TEMPERATURE; DIAGRAM; SUPERCONDUCTORS; LA1-XCAXMNO3 AB High-resolution synchrotron X-ray and neutron powder diffraction techniques have been used to investigate the structural and magnetic phase transitions in two polycrystalline samples with nominal composition (Nd0.5Sr0.5)MnO3. The first sample separates into three coexisting macroscopic phases at low temperature: a ferromagnetic (FM) phase, an orbitally ordered antiferromagnetic A-type (AFM-A) phase, and the majority phase, which shows charge, orbital, and antiferromagnetic CE-type (AFM-CE) ordering. The second sample shows a clean transition from the FM state into the AFM-CE state. The unusual behavior of the first sample is associated with a slight excess of Mn4+ and a wider compositional range with respect to the second sample and illustrates the very delicate competition between these three states near a Mn4+:Mn3+ ratio of unity, where both electron delocalization and charge-ordering are known to occur. The charge-ordered structure of Nd0.5Sr0.5MnO3 is reported. C1 Ohio State Univ, Dept Chem, Columbus, OH 43210 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Indian Inst Sci, Solid State & Struct Chem Unit, Bangalore 560012, Karnataka, India. Univ Calif Santa Barbara, Mat Res Lab, Santa Barbara, CA 93106 USA. RP Woodward, PM (reprint author), Ohio State Univ, Dept Chem, 120 W 18Th Ave, Columbus, OH 43210 USA. RI Rao, C.N.R./B-1569-2009; Vogt, Thomas /A-1562-2011; Ahirwal, Ashish /F-2532-2013 OI Rao, C.N.R./0000-0003-4088-0615; Vogt, Thomas /0000-0002-4731-2787; Ahirwal, Ashish /0000-0002-9127-6541 NR 47 TC 112 Z9 114 U1 0 U2 24 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 DEC PY 1999 VL 11 IS 12 BP 3528 EP 3538 DI 10.1021/cm990281d PG 11 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 269EA UT WOS:000084462500023 ER PT J AU Ma, Y Suib, SL Ressler, T Wong, J Lovallo, M Tsapatsis, M AF Ma, Y Suib, SL Ressler, T Wong, J Lovallo, M Tsapatsis, M TI Synthesis of porous CrOx pillared octahedral layered manganese oxide materials SO CHEMISTRY OF MATERIALS LA English DT Article ID ALPHA-ZIRCONIUM PHOSPHATE; RAY-ABSORPTION SPECTROSCOPY; CLAY CATALYSTS; MONTMORILLONITE CATALYST; OXIDATIVE DEPROTECTION; STRUCTURAL CHEMISTRY; CONVENIENT PROCEDURE; AQUEOUS-SOLUTION; HYDROUS OXIDES; CHROMIUM(III) AB Chromium oxide pillared manganese oxide materials were prepared by intercalating layered manganese oxide with chromium hydroxyl acetate clusters under reflux condition. The as-synthesized materials were heated at 209 degrees C in flowing nitrogen for Ih to result in chromium oxide pillared manganese oxides. X-ray diffraction, UV-vis, FTIR, BET surface area and pore size distribution, temperature programmed desorption, elemental analysis, and X-ray absorption spectrometry were used to study the intercalating process and the structures of the pillared materials. Porous materials with a high specific surface area and a narrow pore size distribution (18 Angstrom) were obtained. The removal of bound water and dehydroxylated water was responsible for the production of high surface area in the pillared material. The decomposition of acetate groups bidentate-linked to Cr starting at 200 degrees C in Na resulted in a concomitant decrease in porosity. Although the ordering of the layers was largely destroyed and the materials remained "amorphous" under XRD study, TEM morphology studies suggest that the material was still layered. EXAFS studies indicate the formation of Cr-O-Mn bonds in the resultant materials via corner-shared linkages of CrO6 and MnO6 octahedra. C1 Univ Connecticut, Dept Chem, Storrs, CT 06269 USA. Univ Connecticut, Dept Chem Engn, Storrs, CT 06269 USA. Univ Connecticut, Inst Sci Mat, Storrs, CT 06269 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Univ Massachusetts, Dept Chem Engn, Goessmann Lab 159, Amherst, MA 01003 USA. RP Suib, SL (reprint author), Univ Connecticut, Dept Chem, U-60, Storrs, CT 06269 USA. NR 59 TC 32 Z9 34 U1 3 U2 10 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 DEC PY 1999 VL 11 IS 12 BP 3545 EP 3554 DI 10.1021/cm990326a PG 10 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 269EA UT WOS:000084462500025 ER PT J AU Yang, CS Kauzlarich, SM Wang, YC AF Yang, CS Kauzlarich, SM Wang, YC TI Synthesis and characterization of germanium/Si-alkyl and germanium/silica core-shell quantum dots SO CHEMISTRY OF MATERIALS LA English DT Article ID POROUS SILICON; VISIBLE PHOTOLUMINESCENCE; LIGHT-EMISSION; SIO2 MATRIX; ELECTRONIC-STRUCTURE; OPTICAL-PROPERTIES; COLLOIDAL SILICON; NANOCRYSTALS; CONFINEMENT; PARTICLES AB Ge/Si-R and Ge/SiO(2) core-shell nanoparticles have been synthesized by a solution route from the stepwise reactions of the Zintl salt, Mg(2)Ge, with SiCl(4) and subsequently either RLi (R = butyl) or H(2)O(2). High-resolution transmission electron microscopy (HRTEM) images show that the core part of these Ge/Si-R and Ge/SiO(2) nanoparticles is crystalline and the d spacing of lattice fringes agrees with the {111} crystal pane (3.27 Angstrom) of Ge. The average sizes (diameter) are 5.8(2.3) and 6.8(2.8) nm for Ge/Si-R and Ge/SiO(2), respectively. Fourier transform-infrared (FTIR) spectra are consistent with alkyl groups bonded to the silicon surface in Ge/Si-R nanoclusters. Off-axis holography was performed for several Ge/SiO(2) nanoparticles. The characterization of the ratio of radii and geometry between the core part and the outer sphere of Ge/SiO(2) is presented. The reconstructed phase image from the hologram offers detailed information concerning the ratio of the shell thickness (R - r) to the radius of the core (r), Rr = (R - r)/r, by measuring the phase shift and the resultant phase contrast. The Rr value from the deconvoluted phase image of a 16 nm spherelike Ge/SiO(2) is 0.264 (0.065). Photoluminescence (PL) spectra of both Ge/Si-R and Ge/SiO(2) nanoclusters show a strong UV-blue PL with a peak centered between 400 and 410 nm. These results suggest that the UV-blue PL may be attributed to the core part of these nanoparticles. C1 Univ Calif Davis, Dept Chem, Davis, CA 95616 USA. Lawrence Berkeley Natl Lab, Natl Ctr Electron Microscopy, Berkeley, CA 94720 USA. RP Kauzlarich, SM (reprint author), FEI Co, Applicat Lab, 7541 NW Evergreen Pkwy, Hillsboro, OR 97124 USA. NR 46 TC 42 Z9 42 U1 0 U2 18 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 DEC PY 1999 VL 11 IS 12 BP 3666 EP 3670 DI 10.1021/cm9905949 PG 5 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 269EA UT WOS:000084462500041 ER PT J AU Li, DQ Duan, L Freimuth, P O'Malley, BW AF Li, DQ Duan, L Freimuth, P O'Malley, BW TI Variability of adenovirus receptor density influences gene transfer efficiency and therapeutic response in head and neck cancer SO CLINICAL CANCER RESEARCH LA English DT Article ID SQUAMOUS-CELL CANCER; IN-VIVO; CARCINOMA; INFECTION; TYPE-2; GROWTH; MODEL; P53 AB Despite encouraging preclinical studies in many tumor types including head and neck squamous cell carcinoma (HNSCC), initial clinical trials with adenovirus-mediated gene therapy have been disappointing. Although the adenovirus is a "highly efficient vector," it is still limited by the extent of effective in. vivo transduction, In our studies,vith multiple human HNSCC cell lines, we have noted a variation in both in vitro and in vivo responses to the same recombinant adenovirus therapeutic construct. We hypothesize that adenovirus receptor density among tumor cell populations, even of the same histology, greatly influences transduction efficiency and therapeutic results of a variety of adenovirus-based gene therapy strategies. To investigate this hypothesis, the numbers of adenovirus receptors on three well-characterized HNSCC cell lines were determined. Marker and cytokine gene transfer efficiencies as well as therapeutic outcomes after adenovirus-mediated tumor suppressor gene and suicide gene therapies were evaluated and correlated with receptor status. A 5-fold variation in adenovirus receptor density was identified among the HNSCC cell lines (P < 0.002, t test). This variation directly correlated with adenovirus type 5 (Ad5)-mediated green fluorescent protein marker gene and Ad5-interleukin 2 cytokine gene transfer efficiency and resulting protein expression in each individual cell line, The receptor density also directly correlated with therapeutic response after Ad5-thymidine kinase or Ad5-p16 gene transfer in each HNSCC line. The role of the adenovirus receptor in gene transfer efficiency was further supported by recombinant Ad5 fiber knob blocking experiments. The marker gene transfer was increasingly blocked by the same concentration of Ad5 recombinant fiber knob in relation to decreasing levels of adenovirus receptor in the HNSCC lines. An Ad5 recombinant construct that carries the shared coxsackie and adenovirus receptor (CAR) was created and used to up-regulate receptors on each cell line. Ad5-CAR infection significantly increased Ad5-beta-Gal gene transfer efficiency and expression (P = 0.0003, Mann-Whitney test). This increased marker gene expression remained consistent with the established pattern of gene transfer efficiency among the HNSCC cell lines. These data confirm the importance of the adenovirus receptor on individual tumor cell lines with respect to investigating novel adenovirus-mediated gene therapy strategies. This work further supports consideration of assaying adenovirus receptor status, even in tumors of the same histology from patients enrolled in gene therapy clinical trials. Adenovirus receptor status may prove valuable for selecting or stratifying patients as well as assessing outcomes among patients within adenovirus-based cancer gene therapy trials. C1 Univ Maryland, Sch Med, Div Otolaryngol Head & Neck Surg, Baltimore, MD 21201 USA. Univ Maryland, Sch Med, Greenebaum Canc Ctr, Baltimore, MD 21201 USA. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP O'Malley, BW (reprint author), Univ Maryland, Sch Med, Div Otolaryngol Head & Neck Surg, 16 S Eutaw St,Suite 500, Baltimore, MD 21201 USA. FU NIDCR NIH HHS [R29 DE11 772-03] NR 28 TC 113 Z9 122 U1 0 U2 1 PU AMER ASSOC CANCER RESEARCH PI BIRMINGHAM PA PO BOX 11806, BIRMINGHAM, AL 35202 USA SN 1078-0432 J9 CLIN CANCER RES JI Clin. Cancer Res. PD DEC PY 1999 VL 5 IS 12 BP 4175 EP 4181 PG 7 WC Oncology SC Oncology GA 267TR UT WOS:000084375800040 PM 10632357 ER PT J AU Im, IG Chen, JH AF Im, IG Chen, JH TI Structure and propagation of triple flames in partially premixed hydrogen-air mixtures SO COMBUSTION AND FLAME LA English DT Article ID DIFFUSION FLAMES; STABILIZATION; JET AB The characteristics of triple flames in a hydrogen-air mixing layer are studied using direct numerical simulation with detailed chemistry. Triple flames are initiated by imposing a temperature ignition source in the center of a scalar mixing layer of nonuniform thickness, thereby forming a pair of freely propagating triple flames. Two different Fuel streams are studied: pure hydrogen and hydrogen diluted with nitrogen. During the ignition stage, the initial ignition runaway is followed by a secondary peak as the ignition kernel transitions to a triple flame, consistent with previous observations. For both diluted and undiluted cases, the triple flame structure exhibits more similarity with a diffusion flame than with a premixed flame, such that the triple point, defined as the location of maximum heat release, is always in the proximity of the stoichiometric mixture fraction line. Similar to a previous study of methanol-air triple flames, the enhancement in the stabilization speed is attributed mainly to how divergence, and its value is proportional to the square root of the density ratio across the flame. In the undiluted case, however, the asymmetric flame structure results in distinct locations where the stabilization speed and the displacement speed are maximum. The effect of unsteady strain rate is also studied by imposing a pair of vortices on the propagating triple flames. The negative strain rate results in the: collapse of the premixed flame branches onto the diffusion flame, forming an edge flame structure. Excessive compressive strain and curvature at the triple flame tip leads to a negative displacement speed. A mixture fraction/temperature parameterization is shown to be useful in representing the structure of a triple flame subjected to unsteady strain rate, (C) 1999 by The Combustion Institute. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. RP Im, IG (reprint author), Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. NR 20 TC 3 Z9 3 U1 2 U2 7 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 DEC PY 1999 VL 119 IS 4 BP 436 EP 454 PG 19 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 251AN UT WOS:000083422600004 ER PT J AU Margolis, SB AF Margolis, SB TI Pulsating hydrodynamic instability and thermal coupling in an extended Landau/Levich model of liquid-propellant combustion: I. Inviscid analysis SO COMBUSTION THEORY AND MODELLING LA English DT Article ID FLAMES; STABILITY AB Hydrodynamic (Landau) instability in combustion is typically associated with the onset of wrinkling of a flame surface, corresponding to the formation of steady cellular structures as the stability threshold is crossed. In the context of liquid-propellant combustion, such instability has recently been shown to occur for critical values of the pressure sensitivity of the burning rate and the disturbance wavenumber, significantly generalizing previous classical results for this problem that assumed a constant normal burning rate. Additionally, however, a pulsating form of hydrodynamic instability has been shown to occur as well, corresponding to the onset of temporal oscillations in the location of the liquid/gas interface. In the present work, we consider the realistic influence of a non-zero temperature sensitivity in the local burning rate on both types of stability thresholds. It is found that for sufficiently small Values of this parameter, there exists a stable range of pressure sensitivities for steady, planar burning such that the classical cellular form of hydrodynamic instability and the more recent pulsating form of hydrodynamic instability can each occur as the corresponding stability threshold is crossed. Far larger thermal sensitivities, however, the pulsating stability boundary evolves into a C-shaped curve in the (disturbance-wavenumber, pressure-sensitivity) plane, indicating loss of stability to pulsating perturbations for all sufficiently large disturbance wavelengths. It is thus concluded, based on characteristic parameter values, that an equally likely form of hydrodynamic instability in liquid-propellant combustion is of a nonsteady, long-wave nature, distinct from the steady, cellular form originally predicted by Landau. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. RP Margolis, SB (reprint author), Sandia Natl Labs, Combust Res Facil, MS 9052, Livermore, CA 94551 USA. NR 17 TC 1 Z9 1 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 1364-7830 J9 COMBUST THEOR MODEL JI Combust. Theory Model. PD DEC PY 1999 VL 3 IS 4 BP 613 EP 635 DI 10.1088/1364-7830/3/4/302 PG 23 WC Thermodynamics; Energy & Fuels; Engineering, Chemical; Mathematics, Interdisciplinary Applications SC Thermodynamics; Energy & Fuels; Engineering; Mathematics GA 277JX UT WOS:000084931400002 ER PT J AU Najm, HN Knio, OM Paul, PH Wyckoff, PS AF Najm, HN Knio, OM Paul, PH Wyckoff, PS TI Response of stoichiometric and rich premixed methane-air flames to unsteady strain rate and curvature SO COMBUSTION THEORY AND MODELLING LA English DT Article ID TURBULENT COMBUSTION; VORTEX; VORTICITY; SIMULATIONS; GENERATION; CHEMISTRY AB The interaction of a premixed methane-air dame with a two-dimensional counterrotating vortex pair is studied under stoichiometric and rich conditions using a detailed C1C2 chemical mechanism. The flame structure and transient response are examined, both at curved cusps and on the vortex-pair centreline. Differences between the two flames are observed in the unsteady behaviour of species mole fractions and production rates. In contrast with earlier one-dimensional opposed-jet flame data, the present results show that the rich flame exhibits a faster response to unsteady strain-rate disturbances than does the stoichiometric flame. Analysis of the results suggest this may be due to the increased dependence of the dame on H, and the decreased role of OH, under rich conditions. Results are also presented from an experimental V-flame vortex-pair interaction study. Measured peak CH and OH data are also found to exhibit a faster flame response under rich conditions. C1 Sandia Natl Labs, Livermore, CA 94551 USA. Johns Hopkins Univ, Baltimore, MD 21218 USA. RP Najm, HN (reprint author), Sandia Natl Labs, Livermore, CA 94551 USA. RI Knio, Omar/A-3318-2010 NR 30 TC 15 Z9 15 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 1364-7830 J9 COMBUST THEOR MODEL JI Combust. Theory Model. PD DEC PY 1999 VL 3 IS 4 BP 709 EP 726 DI 10.1088/1364-7830/3/4/306 PG 18 WC Thermodynamics; Energy & Fuels; Engineering, Chemical; Mathematics, Interdisciplinary Applications SC Thermodynamics; Energy & Fuels; Engineering; Mathematics GA 277JX UT WOS:000084931400006 ER PT J AU Gustafson, J Todi, R AF Gustafson, J Todi, R TI Operations are free; Data motion isn't SO COMPUTER LA English DT Letter C1 US Dept Energy, Ames Lab, Scalable Comp Lab, Ames, IA 50011 USA. RP Gustafson, J (reprint author), US Dept Energy, Ames Lab, Scalable Comp Lab, Ames, IA 50011 USA. NR 1 TC 0 Z9 0 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 DEC PY 1999 VL 32 IS 12 BP 4 EP 4 PG 1 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering SC Computer Science GA 261YU UT WOS:000084039600001 ER PT J AU Foster, I Insley, J von Laszewski, G Kesselman, C Thiebaux, M AF Foster, I Insley, J von Laszewski, G Kesselman, C Thiebaux, M TI Distance visualization: Data exploration on the grid SO COMPUTER LA English DT Article AB Our increased ability to model and measure a wide variety of phenomena has left us awash in data. In the immediate future, the authors anticipate collecting data at the rate of terabytes per day from many classes of applications, including simulations running on teraflop-class computers and experimental data produced by increasingly more sensitive and accurate instruments such as telescopes, microscopes, particle accelerators, and satellites. Generating or acquiring data is not an end in itself but a vehicle for obtaining insights. While data analysis and reduction have a role to play, in many situations we achieve understanding only when a human being interprets the data. Visualization has emerged as an important tool for extracting meaning from the large volumes of data that scientific instruments and simulations produce. The authors describe an online system that supports three-dimensional tomographic image reconstruction-and subsequent collaborative analysis - of data from remote scientific instruments. C1 Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. Univ Chicago, Chicago, IL 60637 USA. Univ So Calif, Inst Informat Sci, Los Angeles, CA 90089 USA. RP Foster, I (reprint author), Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. RI von Laszewski, Gregor/C-2808-2012; OI von Laszewski, Gregor/0000-0001-9558-179X; Kesselman, Carl/0000-0003-0917-1562 NR 11 TC 26 Z9 27 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 DEC PY 1999 VL 32 IS 12 BP 36 EP + DI 10.1109/2.809249 PG 9 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering SC Computer Science GA 261YU UT WOS:000084039600013 ER PT J AU Wendroff, B AF Wendroff, B TI A two-dimensional HLLE Riemann solver and associated Godunov-type difference scheme for gas dynamics SO COMPUTERS & MATHEMATICS WITH APPLICATIONS LA English DT Article DE Riemann solver; Godunov; gas dynamics; two dimensions ID CONSERVATION-LAWS AB The approximate three-state Riemann solver HLLE is formally extended to a nine-state two-dimensional solver. The associated Godunov scheme is outlined and applied to two test problems. Published by Elsevier Science Ltd. C1 Univ Calif Los Alamos Natl Lab, Grp T7, Los Alamos, NM 87544 USA. RP Wendroff, B (reprint author), Univ Calif Los Alamos Natl Lab, Grp T7, POB 1663, Los Alamos, NM 87544 USA. NR 7 TC 25 Z9 25 U1 0 U2 2 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 DEC PY 1999 VL 38 IS 11-12 BP 175 EP 185 DI 10.1016/S0898-1221(99)00296-5 PG 11 WC Mathematics, Applied SC Mathematics GA 262ZZ UT WOS:000084099300017 ER PT J AU Santos, JM Touzet, C AF Santos, JM Touzet, C TI Dynamic update of the reinforcement function during learning SO CONNECTION SCIENCE LA English DT Article DE reinforcement function; reinforcement learning; robot learning; autonomous robot; behaviour-based approach AB During the last decade, numerous contributions have been made to the use of reinforcement learning in the robot learning field. They have focused mainly on the generalization, memorization and exploration issues-mandatory for dealing with real robots. However: it is our opinion that the most difficult task today is to obtain the definition of the reinforcement function (RF). A first attempt in this direction was made by introducing a method-the update parameters algorithm (UPA)-for tuning a RF in such a way that it would be optimal during the exploration phase. The only requirement is to conform to a particular expression of RE in this article, we propose Dynamic-UPA, an algorithm able to tune the RF parameters during the whole learning phase (exploration and exploitation). It allows one to undertake the so-called exploration versus exploitation dilemma through careful computation of the RF parameter values by controlling the ratio between positive and negative reinforcement during learning. Experiments with the mobile robot Khepera in tasks of synthesis of obstacle avoidance and wall-following behaviors validate our proposals. C1 Univ Buenos Aires, FCE&N, Dept Computat, RA-1428 Buenos Aires, DF, Argentina. Oak Ridge Natl Lab, Ctr Engn Sci Adv Res, Oak Ridge, TN 37831 USA. RP Santos, JM (reprint author), Univ Buenos Aires, FCE&N, Dept Computat, Pabellon I, RA-1428 Buenos Aires, DF, Argentina. NR 35 TC 1 Z9 1 U1 2 U2 3 PU CARFAX PUBLISHING PI BASINGSTOKE PA RANKINE RD, BASINGSTOKE RG24 8PR, HANTS, ENGLAND SN 0954-0091 J9 CONNECT SCI JI Connect. Sci. PD DEC PY 1999 VL 11 IS 3-4 BP 267 EP 289 PG 23 WC Computer Science, Artificial Intelligence; Computer Science, Theory & Methods SC Computer Science GA 272HE UT WOS:000084643800004 ER PT J AU Albala, JS Humphery-Smith, I AF Albala, JS Humphery-Smith, I TI Array-based proteomics: High-throughput expression and purification of IMAGE consortium cDNA clones SO CURRENT OPINION IN MOLECULAR THERAPEUTICS LA English DT Article DE bioinformatics; genomics; proteomics ID SINGLE-STEP PURIFICATION; PROTEIN LINKAGE MAP; ESCHERICHIA-COLI; MASS-SPECTROMETRY; GENOMICS; COMPLEX; BACULOVIRUSES; POLYPEPTIDES; PRODUCTS; LIBRARY AB As the sequencing efforts of the Human Genome Project approach closure, the next frontier in the quest to understand how specific genes function will rely upon technical advances in protein analysis. An understanding of protein function will be essential to this process. The development of high-throughput genomic strategies has led to the design of new schemes for genome-scale protein science. Thus, the field of proteomics, the protein complement of genomics, has emerged. Here, we outline the role of proteomics within the genomic sciences, with emphasis toward array-based approaches. A high-throughput protein expression system has been developed for the analysis of the human proteome. This methodology facilitates improved functional and structural analysis of novel genes identified by expressed sequence tag (EST) sequencing and the Human Genome Project. C1 Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94550 USA. Univ Utrecht, Dept Pharmaceut Proteom, NL-3508 TB Utrecht, Netherlands. RP Albala, JS (reprint author), Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, 7000 E Ave L-452, Livermore, CA 94550 USA. NR 32 TC 15 Z9 15 U1 0 U2 1 PU PHARMAPRESS LTD PI LONDON PA MIDDLESEX HOUSE, 34-42 CLEVELAND ST, LONDON W1P 6LB, ENGLAND SN 1464-8431 J9 CURR OPIN MOL THER JI Curr. Opin. Mol. Ther. PD DEC PY 1999 VL 1 IS 6 BP 680 EP 684 PG 5 WC Biotechnology & Applied Microbiology; Medicine, Research & Experimental SC Biotechnology & Applied Microbiology; Research & Experimental Medicine GA 342HL UT WOS:000088639100003 PM 19629864 ER PT J AU Steinkamp, JA Lehnert, NM Keij, JF Lehnert, BE AF Steinkamp, JA Lehnert, NM Keij, JF Lehnert, BE TI Enhanced immunofluorescence measurement resolution of surface antigens on highly autofluorescent, glutaraldehyde-fixed cells analyzed by phase-sensitive flow cytometry SO CYTOMETRY LA English DT Article DE cellular autofluorescence; fibroblasts; glutaraldehyde; fluorescence lifetime; phase-sensitive detection; fluorescent microspheres ID CELLULAR AUTOFLUORESCENCE; BACKGROUND AUTOFLUORESCENCE; FLUORESCENCE LIFETIME; LABELED CELLS; PARTICLES; FLAVINS; SIGNALS; SYSTEMS; NUMBER; LASER AB Background: The primary source of interference in immunofluorescence measurements by flow cytometry is background autofluorescence. Methods: Using human lung fibroblasts (HLFs) as an autofluorescent cell model, unfixed HLFs and HLFs fixed in methanol, ethanol, formaldehyde, paraformaldehyde and glutaraldehyde were analyzed by phase-sensitive flow cytometry to compare their fluorescence intensity and lifetime histograms. Based on these results, a surface antigen on HLFs was labeled with a fluorescein isothiocyanate (FITC) conjugated antibody and fixed in glutaraldehyde, and the cells were analyzed by conventional and phase-resolved methods. Results: The lifetimes of unfixed and ethanol-, methanol-, paraformaldehyde- and formaldehyde-fixed HLFs were in the 1.7-1.9 nanosecond (ns) range, with coefficients of variation 25-35%. Since the autofluorescence lifetime histograms of unfixed and fixed HLFs partially overlapped the 3.5 ns lifetime histogram of FITC-labeled microspheres, which were used to approximate FITC-antibody labeling of HLFs, the ability to resolve FITC-labeled probe, based on differences in the FITC and autofluorescence lifetimes, was severely Limited. When HLFs labeled with an FITC-antibody cell-surface marker were fixed in glutaraldehyde (autofluorescence lifetime 0.9-1.4 ns, coefficient of variation approximate to 11%) and analyzed by phase-resolved methods, the results showed that FITC-antibody labeling could be readily resolved from background autofluorescence. Conclusions: Phase-sensitive detection improves the immunofluorescence measurement resolution of surface antigens on highly autofluorescent, glutaraldehyde-fixed cells. Cytometry 37: 275-283, 1999. Published 1999 Wiley-Liss, Inc.dagger C1 Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. RP Steinkamp, JA (reprint author), Univ Calif Los Alamos Natl Lab, Div Life Sci, M-S M888, Los Alamos, NM 87545 USA. FU NCRR NIH HHS [R01-RR07855, P41-RR013150] NR 33 TC 14 Z9 14 U1 0 U2 2 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0196-4763 J9 CYTOMETRY JI Cytometry PD DEC 1 PY 1999 VL 37 IS 4 BP 275 EP 283 DI 10.1002/(SICI)1097-0320(19991201)37:4<275::AID-CYTO4>3.0.CO;2-U PG 9 WC Biochemical Research Methods; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 260FH UT WOS:000083938500004 PM 10547612 ER PT J AU O'Neill, RV Riitters, KH Wickham, JD Jones, KB AF O'Neill, RV Riitters, KH Wickham, JD Jones, KB TI Landscape pattern metrics and regional assessment SO ECOSYSTEM HEALTH LA English DT Article ID LAND-USE CHANGE; DEVELOPMENT POLICIES; MULTISCALE ANALYSIS; SPATIAL PATTERNS; ECOLOGICAL RISK; SCALE; CONTAGION; FOREST; DEFORESTATION; ENVIRONMENT AB The combination of remote imagery data, geographic information systems software, and landscape ecology theory provides a unique basis for monitoring and assessing large-scale ecological systems. The unique feature of the work has been the need to develop and interpret quantitative measures of spatial pattern-the landscape indices. This article reviews what is known about the statistical properties of these pattern metrics and suggests some additional metrics based on island biogeography, percolation theory, hierarchy theory, and economic geography. Assessment applications of this approach have required interpreting the pattern metrics in terms of specific environmental endpoints, such as wildlife and water quality, and research into how to represent synergystic effects of many overlapping sources of stress. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. N Carolina State Univ, US Geol Survey, Raleigh, NC 27695 USA. US EPA, Res Triangle Pk, NC 27711 USA. US EPA, Las Vegas, NV 89193 USA. RP O'Neill, RV (reprint author), Oak Ridge Natl Lab, Bldg 1505 MS-4036, Oak Ridge, TN 37831 USA. NR 77 TC 81 Z9 109 U1 5 U2 29 PU BLACKWELL SCIENCE INC PI MALDEN PA 350 MAIN ST, MALDEN, MA 02148 USA SN 1076-2825 J9 ECOSYST HEALTH JI Ecosyst. Health PD DEC PY 1999 VL 5 IS 4 BP 225 EP 233 DI 10.1046/j.1526-0992.1999.09942.x PG 9 WC Ecology; Environmental Studies SC Environmental Sciences & Ecology GA 279RR UT WOS:000085059400002 ER PT J AU Boughton, DA Smith, ER O'Neill, RV AF Boughton, DA Smith, ER O'Neill, RV TI Regional vulnerability: A conceptual framework SO ECOSYSTEM HEALTH LA English DT Editorial Material ID DYNAMICS; QUALITY AB Regional vulnerability assessment, or ReVA, is an approach to place-based ecological risk assessment that is currently under development by the off ice of Research and Development of the U.S. Environmental Protection Agency (EPA). The assessment is done at the scale of EPA regions and builds on data collected for the Environmental Monitoring and Assessment Program (EMAP) of the EPA. The pilot ReVA is being developed for the U.S, mid-Atlantic region to identify those ecosystems, together with the ecological goods and services they provide, that are most vulnerable to being lost in the next 20 years. The project is currently exploring different conceptual approaches to integrated assessment. In this article, we give an operational approach to estimating ecosystem vulnerability and discuss important issues arising from it. The first issue is estimating vulnerability at the regional scale as opposed to the more familiar local scale. The second issue is integrating information about different sorts of risks in order to prioritize them at the regional scale. The challenge of integration is considerable because of the possibility of synergistic (mutually reinforcing) interactions between different environmental stresses. Synergistic effects are often too poorly known to include, yet potentially too important to ignore. Vulnerability at the regional scale may provide a pragmatic, middle-road approach to this problem by highlighting and characterizing geographic areas that are expected to change the most in the future. The goal is not exact predictions, but a first-cut early warning system to identify and prioritize the risks of undesirable environmental changes over the next few decades. C1 US EPA, Off Res & Dev, Natl Exposure Res Lab, Res Triangle Pk, NC 27711 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Smith, ER (reprint author), US EPA, Off Res & Dev, Natl Exposure Res Lab, MD-75, Res Triangle Pk, NC 27711 USA. NR 33 TC 27 Z9 32 U1 2 U2 14 PU BLACKWELL SCIENCE INC PI MALDEN PA 350 MAIN ST, MALDEN, MA 02148 USA SN 1076-2825 J9 ECOSYST HEALTH JI Ecosyst. Health PD DEC PY 1999 VL 5 IS 4 BP 312 EP 322 DI 10.1046/j.1526-0992.1999.09949.x PG 11 WC Ecology; Environmental Studies SC Environmental Sciences & Ecology GA 279RR UT WOS:000085059400009 ER PT J AU Wilson, RE Zevenbergen, GA Mah, DL Murphy, AJ AF Wilson, RE Zevenbergen, GA Mah, DL Murphy, AJ TI Calculation of transmission line parameters from synchronized measurements SO ELECTRIC MACHINES AND POWER SYSTEMS LA English DT Article AB Accurate knowledge of transmission system parameters, such as series impedance, optimizes distance relay settings and impedance-based fault location. A new method is developed to measure transmission line impedances and admittances from synchronized phasor measurements. Power system voltage and current phasors were recorded during commissioning tests of a 525 kV transmission system containing shunt and series compensation. Steady-state phase angles (delta) and magnitudes of line-side voltages and currents were measured relative to a satellite-based global time standard at two substations. Fairs of synchronized measurements were used to directly calculate real-time steady-state ABCD parameters. For comparison, two-port ABCD transmission system parameters were derived by classical methods and from an ElectroMagnetics Transients Program (EMTP) transmission system design model. To verify the accuracy of the measured parameters, a new method comparing field measured with calculated power flows was developed. Sending-end power flow was measured from accurate recordings and was compared with pourer flow calculated using the three estimates of ABCD parameters, sending-end voltages, and receiving-end voltages. Close agreement was found between field-measured pourer flows and calculations using the measured ABCD parameters. C1 US DOE, Western Area Power Adm, Golden, CO USA. RP Wilson, RE (reprint author), US DOE, Western Area Power Adm, Golden, CO USA. NR 16 TC 20 Z9 22 U1 0 U2 2 PU HEMISPHERE PUBL CORP PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 USA SN 0731-356X J9 ELECTR MACH POW SYST JI Electr. Mach. Power Syst. PD DEC PY 1999 VL 27 IS 12 BP 1269 EP 1278 DI 10.1080/073135699268560 PG 10 WC Engineering, Electrical & Electronic SC Engineering GA 260AN UT WOS:000083926300002 ER PT J AU Stauber, RE Perkins, JD Parilla, PA Ginley, DS AF Stauber, RE Perkins, JD Parilla, PA Ginley, DS TI Thin film growth of transparent p-type CuAlO2 SO ELECTROCHEMICAL AND SOLID STATE LETTERS LA English DT Article AB Recent results suggest that CuAlO2 may be a p-type transparent conductor, but thin film synthesis is difficult because of the complex Cu: Al:O phase diagram. We report a robust method of making c-axis oriented CuAlO2 thin films. Thin film precursors of CuAlO2 were deposited on sapphire (001) substrates by radio-frequency sputtering and by pulsed-laser deposition. Subsequent annealing in air at 1050 degrees C in a closed crucible containing Al2O3 and CuO powders yielded nearly phase-pure, biaxially textured CuAlO2. The films were p-type and transparent with a gap of 3.5 eV. (C) 1999 The Electrochemical Society. S1099-0062(99)08-006-2. All rights reserved. C1 Univ Colorado, Boulder, CO 80309 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Stauber, RE (reprint author), Univ Colorado, Boulder, CO 80309 USA. NR 10 TC 65 Z9 69 U1 1 U2 29 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 DEC PY 1999 VL 2 IS 12 BP 654 EP 656 DI 10.1149/1.1390938 PG 3 WC Electrochemistry; Materials Science, Multidisciplinary SC Electrochemistry; Materials Science GA 249QN UT WOS:000083343900017 ER PT J AU Murphy, FV Sweet, RM Churchill, MEA AF Murphy, FV Sweet, RM Churchill, MEA TI The structure of a chromosomal high mobility group protein-DNA complex reveals sequence-neutral mechanisms important for non-sequence-specific DNA recognition SO EMBO JOURNAL LA English DT Article DE chromatin; DNA binding; HMG domain; nonsequence-specific; X-ray crystallography ID ARCHITECTURE-SPECIFIC PROTEIN; DETERMINING FACTOR SRY; CO-CRYSTAL STRUCTURE; HMG-D; NUCLEOPROTEIN STRUCTURES; DROSOPHILA-MELANOGASTER; TRANSCRIPTION FACTORS; BINDING PROPERTIES; MOLECULAR-BASIS; NUCLEIC-ACIDS AB The high mobility group (HMG) chromosomal proteins, which are common to all eukaryotes, bind DNA in a non-sequence-specific fashion to promote chromatin function and gene regulation. They interact directly with nucleosomes and are believed to be modulators of chromatin structure. They are also important in V(D)J recombination and in activating a number of regulators of gene expression, including p53, Hox transcription factors and steroid hormone receptors, by increasing their affinity for DNA. The X-ray crystal structure, at 2.2 Angstrom resolution, of the HMG domain of the Drosophila melanogaster protein, HMG-D, bound to DNA provides the first detailed view of a chromosomal HMG domain interacting with linear DNA and reveals the molecular basis of non-sequence-specific DNA recognition. Ser10 forms water-mediated hydrogen bonds to DNA bases, and Va132 with Thr33 partially intercalates the DNA, These two 'sequence-neutral' mechanisms of DNA binding substitute for base-specific hydrogen bonds made by equivalent residues of the sequence-specific HMG domain protein, lymphoid enhancer factor-1. The use of multiple intercalations and water-mediated DNA contacts may prove to be generally important mechanisms by which chromosomal proteins bind to DNA in the minor groove. C1 Univ Colorado, Hlth Sci Ctr, Dept Pharmacol, Denver, CO 80262 USA. Univ Illinois, Dept Biochem, Urbana, IL 61801 USA. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Churchill, MEA (reprint author), Univ Colorado, Hlth Sci Ctr, Dept Pharmacol, 4200 E 9th Ave, Denver, CO 80262 USA. RI Churchill, Mair/C-5549-2014 OI Churchill, Mair/0000-0003-0862-235X FU NCRR NIH HHS [RR12408-01A1]; NIGMS NIH HHS [GM-53163, R01 GM059456, R01 GM059456-02, R01 GM059456-03, R01 GM059456-04, R01 GM059456-05, R01-GM59456] NR 66 TC 149 Z9 152 U1 0 U2 4 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0261-4189 J9 EMBO J JI Embo J. PD DEC 1 PY 1999 VL 18 IS 23 BP 6610 EP 6618 DI 10.1093/emboj/18.23.6610 PG 9 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 264JQ UT WOS:000084177700003 PM 10581235 ER PT J AU Bulavin, DV Saito, S Hollander, MC Sakaguchi, K Anderson, CW Appella, E Fornace, AJ AF Bulavin, DV Saito, S Hollander, MC Sakaguchi, K Anderson, CW Appella, E Fornace, AJ TI Phosphorylation of human p53 by p38 kinase coordinates N-terminal phosphorylation and apoptosis in response to UV radiation SO EMBO JOURNAL LA English DT Article DE apoptosis; DNA damage; p38; p53; phosphorylation ID DNA-DAMAGE; ULTRAVIOLET-RADIATION; GAMMA-RADIATION; ACTIVATES P53; GROWTH ARREST; IN-VIVO; PROTEIN; STRESS; ACETYLATION; STABILIZES AB Components of the ras signaling pathway contribute to activation of cellular p53, In MCF-7 cells, p38 kinase activated p53 more effectively than other members of the ras pathway. p53 and p38 kinase exist in the same physical complex, and co-expression of p38 stabilized p53 protein. In vitro, p38 kinase phosphorylated p53 at Ser33 and Ser46, a newly identified site, Mutation of these sites decreased p53-mediated and UV-induced apoptosis, and the reduction correlated with total abrogation of UV-induced phosphorylation on Ser37 and a significant decrease in Ser15 phosphorylation in mutant p53 containing alanine at Ser33 and Ser46, Inhibition of p38 activation after UV irradiation decreased phosphorylation of Ser33, Ser37 and Ser15, and also markedly reduced UV-induced apoptosis in a p53-dependent manner. These results suggest that p38 kinase plays a prominent role in an integrated regulation of N-terminal phosphorylation that regulates p53-mediated apoptosis after UV radiation. C1 NCI, Div Basic Sci, NIH, Bethesda, MD 20892 USA. NCI, Cell Biol Lab, NIH, Bethesda, MD 20892 USA. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Fornace, AJ (reprint author), NCI, Div Basic Sci, NIH, Bethesda, MD 20892 USA. RI Fornace, Albert/A-7407-2008 OI Fornace, Albert/0000-0001-9695-085X FU NIGMS NIH HHS [GM52825] NR 35 TC 487 Z9 498 U1 4 U2 22 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0261-4189 J9 EMBO J JI Embo J. PD DEC 1 PY 1999 VL 18 IS 23 BP 6845 EP 6854 DI 10.1093/emboj/18.23.6845 PG 10 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 264JQ UT WOS:000084177700026 PM 10581258 ER PT J AU Scott, MJ Sands, RD Edmonds, J Liebetrau, AM Engel, DW AF Scott, MJ Sands, RD Edmonds, J Liebetrau, AM Engel, DW TI Uncertainty in integrated assessment models: modeling with MiniCAM 1.0 SO ENERGY POLICY LA English DT Article DE climate change; policy; integrated assessment; uncertainty ID POLICY ANALYSIS; CLIMATE; EMISSIONS; AEROSOLS AB Human-initiated climate change remains one of the major science-based public policy issues facing the nations of the world. One feature of the issue that inhibits effective decisions is the ubiquity of uncertainty: many if not most of the parameters of mathematical relationships that forecast emissions, atmospheric processes, impacts, and effectiveness of countermeasures are uncertain. We have added a stochastic simulation capability to the commonly used integrated assessment model MiniCAM 1.0 to analyze the sources of uncertainty and their relative importance and to help devise strategies for depicting and coping with uncertainty. The analysis shows that: (1) the projected range of uncertainty in global temperature increase during the next century is greater than previously supposed, but the central tendency is not dramatically higher; (2) many of the major sources of uncertainty previously discussed in the literature remain significant, but not all; (3) an adaptive policy of "act, then learn, then act" appears to offer better prospects for balancing uncertain costs and benefits of controlling greenhouse gas emissions than do rigid precautionary measures; and (4) current targets for atmospheric stabilization appear excessively ambitious. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Scott, MJ (reprint author), Pacific NW Natl Lab, POB 999,Mail Stop K8-17, Richland, WA 99352 USA. NR 45 TC 13 Z9 13 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0301-4215 EI 1873-6777 J9 ENERG POLICY JI Energy Policy PD DEC PY 1999 VL 27 IS 14 BP 855 EP 879 DI 10.1016/S0301-4215(99)00057-9 PG 25 WC Energy & Fuels; Environmental Sciences; Environmental Studies SC Energy & Fuels; Environmental Sciences & Ecology GA 285UB UT WOS:000085405500004 ER PT J AU Teotia, A Vyas, A Cuenca, R Stodolsky, F Eberhardt, J AF Teotia, A Vyas, A Cuenca, R Stodolsky, F Eberhardt, J TI CAFE compliance by light trucks: economic impacts of clean diesel engine SO ENERGY POLICY LA English DT Article DE CAFE standards; truck diesels; economic impacts AB With the popularity of light trucks increasing in the United States, their share of the US light vehicle market had doubled between 1980 and 1996, climbing from 20 to 40%. By 1996, annual energy consumption for light trucks had risen to 5.97 x 10(15) Btu [5.97 quadrillion Btu, or "quad," or 6.30 x 10(18) joule (J)], compared to 7.94 quad (8.38 x 10(18) J) for cars. In recent years (since 1995), the fuel economy of US-manufactured light trucks (almost 99% of which use gasoline engines) has been below the Corporate Average Fuel Economy (CAFE) standards. This paper analyzes a strategy to reduce the CAFE shortfalls by adopting the new, highly energy-efficient clean diesel engine. Research on such engines has been funded by the US Department of Energy, Office of Heavy Vehicle Technologies, under its Light Truck Clean Diesel Engine Program. A clean diesel engine market penetration trajectory is developed, representing an industry response to meet the CAFE standards. Whether the engine will be produced inside the country or imported remains uncertain, so two cases are defined. Values of exports/imports of dean diesel engines/trucks under these cases are estimated. The macroeconomic benefits are estimated by using a model of the US economy developed by Standard & Poor's Data Resources, Inc. On the basis of gains in the gross domestic product projected under the alternative cases, domestic production of the clean diesel engine is favored over importing it. (C) 2000 Elsevier Science Ltd, All rights reserved. C1 Argonne Natl Lab, Div Energy Syst, Argonne, IL 60439 USA. US DOE, Washington, DC 20585 USA. RP Teotia, A (reprint author), Argonne Natl Lab, Div Energy Syst, 9700 S Cass Ave,Bldg 362, Argonne, IL 60439 USA. NR 18 TC 3 Z9 4 U1 1 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0301-4215 J9 ENERG POLICY JI Energy Policy PD DEC PY 1999 VL 27 IS 15 BP 889 EP 900 DI 10.1016/S0301-4215(99)00090-7 PG 12 WC Energy & Fuels; Environmental Sciences; Environmental Studies SC Energy & Fuels; Environmental Sciences & Ecology GA 286PD UT WOS:000085453600002 ER PT J AU Tonn, B AF Tonn, B TI Sustainable cities and energy policies SO ENVIRONMENT AND PLANNING C-GOVERNMENT AND POLICY LA English DT Book Review C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Tennessee, Sch Planning, Knoxville, TN 37996 USA. RP Tonn, B (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU PION LTD PI LONDON PA 207 BRONDESBURY PARK, LONDON NW2 5JN, ENGLAND SN 0263-774X J9 ENVIRON PLANN C JI Environ. Plan. C-Gov. Policy PD DEC PY 1999 VL 17 IS 6 BP 773 EP 774 PG 2 WC Environmental Studies; Public Administration SC Environmental Sciences & Ecology; Public Administration GA 267MG UT WOS:000084361300008 ER PT J AU Munro, NB Talmage, SS Griffin, GD Waters, LC Watson, AP King, JF Hauschild, V AF Munro, NB Talmage, SS Griffin, GD Waters, LC Watson, AP King, JF Hauschild, V TI The sources, fate, and toxicity of chemical warfare agent degradation products SO ENVIRONMENTAL HEALTH PERSPECTIVES LA English DT Review DE anticholinesterase; blood agent; CK; cyanogen chloride; decontamination; GA; GB; GD; HD; HN; hydrolysis; Lewisite; microbial degradation; nerve agent; nitrogen mustard; oxidation; sarin; soman; sulfur mustard; tabun; VX; vesicant ID CHROMATOGRAPHY-MASS-SPECTROMETRY; SISTER-CHROMATID EXCHANGES; SALMONELLA MUTAGENICITY TESTS; MUSTARD HYDROLYSIS PRODUCTS; DOMINANT LETHAL ASSAY; MOUSE LYMPHOMA-CELLS; HAMSTER OVARY CELLS; ORGANOPHOSPHORUS COMPOUNDS; CHROMOSOME ABERRATION; METHYL-METHACRYLATE AB We include in this review an assessment of the formation, environmental fate, and mammalian and ecotoxicity of CW agent degradation products relevant to environmental and occupational health. These parent CW agents include several vesicants: sulfur mustards [undistilled sulfur mustard (H), sulfur mustard (HD), and an HD/agent T mixture (HT)]; nitrogen mustards [ethylbis(2-chloroethyl)amine (HN1), methylbis(2-chloroethyl)amine (HN2), tris(2-chloroethyl)amine (HN3)], and Lewisite; four nerve agents {O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate (VX), tabun (GA), sarin (GB), and soman (GD)}; and the blood agent cyanogen chloride. The degradation processes considered here include hydrolysis, microbial degradation, oxidation, and photolysis. We also briefly address decontamination but not combustion processes. Because CW agents are generally not considered very persistent, certain degradation products of significant persistence, even those that are not particularly toxic, may indicate previous CW agent presence or that degradation has occurred. Of those products for which there are data on both environmental fate and toxicity, only a few are both environmentally persistent and highly toxic. Major degradation products estimated to be of significant persistence (weeks to years) include thiodiglycol for HD; Lewisite oxide for Lewisite; and ethyl methyl phosphonic acid, methyl phosphonic acid, and possibly S-(2-diisopropylaminoethyl) methylphosphonothioic acid (EA 2192) for VX. Methyl phosphonic acid is also the ultimate hydrolysis product of both GB and GD. The GB product, isopropyl methylphosphonic acid, and a closely related contaminant of GB, diisopropyl methylphosphonate, are also persistent. Of all of these compounds, only Lewisite oxide and EA 2192 possess high mammalian toxicity. Unlike other CW agents, sulfur mustard agents (e.g., HD) are somewhat persistent; therefore, sites or conditions involving potential HD contamination should include an evaluation of both the agent and thiodiglycol. C1 Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37830 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37830 USA. USA, Ctr Environm, Aberdeen Proving Ground, MD USA. USA, Ctr Hlth Promot & Prevent Med, Aberdeen Proving Ground, MD USA. RP Talmage, SS (reprint author), Oak Ridge Natl Lab, Div Life Sci, 1060 Commerce Pk, Oak Ridge, TN 37830 USA. NR 398 TC 287 Z9 298 U1 24 U2 132 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 DEC PY 1999 VL 107 IS 12 BP 933 EP 974 PG 42 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA 271DL UT WOS:000084578900015 PM 10585900 ER PT J AU McNab, WW AF McNab, WW TI Comparisons of geochemical signatures of biotransformation of fuel hydrocarbons in groundwater SO ENVIRONMENTAL MONITORING AND ASSESSMENT LA English DT Article DE biodegradation; groundwater geochemistry ID CONTAMINATED AQUIFER; SULFATE REDUCTION; BENZENE; DEGRADATION; TOLUENE; OXIDATION; SAND; IRON AB Biotransformation processes play an active role in reducing the environmental impact of fuel hydrocarbon releases to groundwater. Because monitoring data at release locations are typically sparse, spatial variations in geochemical indicator parameters are often called upon as indirect evidence of biotransformation. These parameters include concentrations of electron acceptors (O-2, NO3-, SO42-), reduced redox reaction by-products (Fe2+, Mn2+, CH4), as well as bicarbonate alkalinity, pH and E-h. However, background variability in a number of these parameters complicates the task of data interpretation, particularly in the case of small data sets. In this study, correlation analyses are applied to geochemical indicator data at six hydrocarbon groundwater contamination sites in California to identify which parameters are the most reliable indicators. The results of the analyses suggest that the most direct indicators of the local redox environment - Fe2+, Mn2+, CH4, E-h - yield the most consistent evidence of hydrocarbon biotransformation. Indicators which rely largely on mass balance - O-2, NO3-, SO42-, alkalinity - appear to be less reliable. These findings may provide guidance in both the collection and interpretation of groundwater monitoring data at hydrocarbon contamination sites. C1 Univ Calif Lawrence Livermore Natl Lab, Environm Restorat Div, Livermore, CA 94550 USA. RP McNab, WW (reprint author), Univ Calif Lawrence Livermore Natl Lab, Environm Restorat Div, POB 808,L-530, Livermore, CA 94550 USA. NR 19 TC 2 Z9 3 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-6369 J9 ENVIRON MONIT ASSESS JI Environ. Monit. Assess. PD DEC PY 1999 VL 59 IS 3 BP 257 EP 274 DI 10.1023/A:1006113520693 PG 18 WC Environmental Sciences SC Environmental Sciences & Ecology GA 248KZ UT WOS:000083274900002 ER PT J AU Marano, JJ Rogers, S AF Marano, JJ Rogers, S TI Process system optimization for life cycle improvement SO ENVIRONMENTAL PROGRESS LA English DT Article AB Life Cycle Assessment (LCA) is an analytic tool for quantifying the environmental impacts of all processes used in converting raw materials into a final product. The LCA consists of three parts. Life cycle inventory quantifies all material and energy use, and environmental emissions for the entire product life cycle, while impact assessment evaluates actual and potential environmental and human health consequences of the activities identified in the inventory phase. Most importantly, life cycle improvement aims at reducing the risk of these consequences occurring to make the product more benign. When the LCA is performed in conjunction with a technoeconomic analysis, the total economic and environmental benefits and shortcomings of a product or process can be quantified. A methodology has been developed incorporating process performance, economics, and life cycle inventory data to synthesize process systems, which meet life cycle impact-improvement targets at least cost. The method relies on a systematic description of the product life cycle and utilizes successive Linear Programming to formulate and optimize the non-linear, constrained problem which results. The practicality and power of this approach have been demonstrated by examining options for the reduction of emissions of the greenhouse gas CO2 from petroleum-based fuels. C1 Fed Energy Technol Ctr, Pittsburgh, PA 15236 USA. RP Marano, JJ (reprint author), Fed Energy Technol Ctr, POB 10940, Pittsburgh, PA 15236 USA. NR 8 TC 1 Z9 2 U1 0 U2 1 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0278-4491 J9 ENVIRON PROG JI Environ. Prog. PD WIN PY 1999 VL 18 IS 4 BP 267 EP 272 DI 10.1002/ep.670180413 PG 6 WC Engineering, Environmental; Engineering, Chemical; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 274XB UT WOS:000084789400008 ER PT J AU Tatara, CP Mulvey, M Newman, MC AF Tatara, CP Mulvey, M Newman, MC TI Genetic and demographic responses of mosquitofish (Gambusia holbrooki) populations exposed to mercury for multiple generations SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE genetics; mercury; allozymes; selection; Gambusia holbrooki ID KREBS CYCLE METABOLITES; ALLOZYME GENOTYPE; ISOMERASE ALLOZYMES; INORGANIC MERCURY; AFFINIS BAIRD; GIRARD 1859; SUSCEPTIBILITY; VERIFICATION; GLYCOLYSIS; SELECTION AB Genetic and demographic responses of mosquitofish were examined after multiple generations of exposure to mercury. Previous studies of acute lethal exposures of mosquitofish to either mercury or arsenic demonstrated a consistent correlation between time to death and genotype at the glucosephosphate isomerase-2 (Gpi-2) locus. A mesocosm study involving mosquitofish populations exposed to mercury for ill d showed significant female sexual selection and fecundity selection at the Gpi-2 locus. Here the mesocosm study was extended to populations exposed to mercury for several (approx, four) generations. After 2 years, control and mercury-exposed populations met Hardy-Weinberg expectations and showed no evidence of generic bottlenecks. The mean number of heterozygous loci did not differ significantly between the mercury-exposed and control populations. Significant differences in allele frequencies at the Gpi-2 locus were observed between the mercury-exposed and control populations. Relative to the initial and control allele frequencies, the Gpi-2(100) allele frequency was lower, the Gpi-2(66) allele frequency increased, but the Gpi-2(38) allele frequency did not change in mercury-exposed populations. No significant differences were found in standard length, weight, sex ratio, or age class ratio between the control and mercury-exposed populations. Allele frequency changes at the Gpi-2 locus suggest population-level response to chronic mercury exposure. Changes in allele frequency may be useful as indicators of population response to contaminants, provided that the population in question is well understood. C1 Univ Georgia, Savannah River Ecol Lab, Aiken, SC 29802 USA. Virginia Inst Marine Sci, Coll William & Mary, Sch Marine Sci, Gloucester Point, VA 23062 USA. RP Tatara, CP (reprint author), Univ Georgia, Savannah River Ecol Lab, PO Drawer E, Aiken, SC 29802 USA. RI Langerhans, R./A-7205-2009 NR 26 TC 21 Z9 24 U1 1 U2 10 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 DEC PY 1999 VL 18 IS 12 BP 2840 EP 2845 DI 10.1897/1551-5028(1999)018<2840:GADROM>2.3.CO;2 PG 6 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 258ZV UT WOS:000083870300026 ER PT J AU Moore, DRJ Sample, BE Suter, GW Parkhurst, BR Teed, RS AF Moore, DRJ Sample, BE Suter, GW Parkhurst, BR Teed, RS TI A probabilistic risk assessment of the effects of methylmercury and PCBS on mink and kingfishers along East Fork Poplar Creek, Oak Ridge, Tennessee, USA SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE probabilistic risk assessment; mink; kingfisher; mercury; polychlorinated biphenyls ID GENERALIZED LINEAR-MODELS; POLYCHLORINATED-BIPHENYLS; MERCURY ACCUMULATION; STREAM HABITAT; CERYLE-ALCYON; AROCLOR 1254; REPRODUCTION; BIOACCUMULATION; TOXICITY; FISH AB Over fifty years of operations, storage, and disposal of wastes from the U.S. Department of Energy (U.S. DOE) Y-12 nuclear weapons facility at Oak Ridge, Tennessee, USA, has resulted in the contamination of water sediment, biota, and floodplain soils of East Fork Poplar Creek. A preliminary assessment revealed that methylmercury and polychlorinated biphenyls (PCBs) were the contaminants of most concern. Because these contaminants are persistent, accumulate in tissues, and biomagnify up the food chain, piscivorous wildlife are the biota at greatest risk of exposure. The objective of this study was to estimate the risks posed by methylmercury and PCBs to two piscivorous species: mini; and belted kingfishers. We conducted Monte Carlo simulations to estimate total daily intakes of each contaminant by each species and then integrated the resulting distributions with their respective dose-response curves to estimate risks. The results indicate that methylmercury poses a moderate risk to female mink (24% probability of at least 15% mortality) and kingfishers (50% probability of at least a 12-28% decline in fecundity depending on location). The PCBs pose a very serious risk to mink (52% probability of at least a 50% decline in reproductive fecundity), a species known to be especially sensitive to the effects of organochlorine substances, but little risk to kingfishers (<5% probability of a decline in reproductive fecundity greater than 10% at any location). C1 Cadmus Grp, Ottawa, ON K2A 3X9, Canada. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Cadmus Grp, Laramie, WY 82070 USA. RP Moore, DRJ (reprint author), Cadmus Grp, 411 Roosevelt Ave,Suite 204, Ottawa, ON K2A 3X9, Canada. EM dmoore@cadmusgroup.com NR 69 TC 31 Z9 33 U1 4 U2 15 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0730-7268 EI 1552-8618 J9 ENVIRON TOXICOL CHEM JI Environ. Toxicol. Chem. PD DEC PY 1999 VL 18 IS 12 BP 2941 EP 2953 DI 10.1897/1551-5028(1999)018<2941:APRAOT>2.3.CO;2 PG 13 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 258ZV UT WOS:000083870300041 ER PT J AU Moore, DRJ Sample, BE Suter, GW Parkhurst, BR Teed, RS AF Moore, DRJ Sample, BE Suter, GW Parkhurst, BR Teed, RS TI Risk-based decision making: The East Fork Poplar Creek case study SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE decision making; mink; kingfishers; mercury; polychlorinated biphenyls ID UNCERTAINTY AB A probabilistic risk assessment revealed that methylmercury released from the U.S. Department of Energy (DOE) Y-12 weapons facility at Oak Ridge, Tennessee, USA, poses moderate risks to mink and kingfishers residing near the receiving waters of East Fork Poplar Creek. Polychlorinated biphenyls (PCBs) released from this facility Dose severe risks to mink but little risk to kingfishers. The objective of this study was to use a risk-based decision-making approach to select remedial cleanup levels for each of these contaminants. We conducted Monte Carlo simulations to estimate total daily intakes of each contaminant by mink (mercury and PCBs) and kingfishers (PCBs only) for a range of exposure-reduction scenarios. The resulting exposure distributions were then integrated with their respective dose-response curves to estimate postremediation risks. The results indicated that total mercury levels in surface water would need to be reduced from current levels (mean = 0.225 mu g/L) to 0.03 to 0.05 mu g/L to reduce risks to very low levels (<5% probability of greater than or equal to 10% mortality) for both mink and kingfishers. If interested parties define acceptable risk as, for example, a 20% probability of greater than or equal to 10% mortality, then mercury levels would need to be reduced to 0.14 mu g/L. The PCBs analysis indicated that reducing water-borne exposures would produce only a modest reduction in risk to mink because much of the current exposure is through terrestrial exposure pathways. C1 Cadmus Grp, Ottawa, ON K2A 3X9, Canada. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Cadmus Grp, Laramie, WY 82070 USA. RP Moore, DRJ (reprint author), Cadmus Grp, 411 Roosevelt Ave,Suite 204, Ottawa, ON K2A 3X9, Canada. NR 11 TC 3 Z9 3 U1 1 U2 5 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 DEC PY 1999 VL 18 IS 12 BP 2954 EP 2958 DI 10.1897/1551-5028(1999)018<2954:RBDMTE>2.3.CO;2 PG 5 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 258ZV UT WOS:000083870300042 ER PT J AU Hoellinger, F Gall, BJP Schulz, N Urban, W Ahmad, I Bentaleb, M Durell, JL Jones, MA Leddy, M Lubkiewicz, E Morss, LR Phillips, WR Smith, AG Varley, BJ AF Hoellinger, F Gall, BJP Schulz, N Urban, W Ahmad, I Bentaleb, M Durell, JL Jones, MA Leddy, M Lubkiewicz, E Morss, LR Phillips, WR Smith, AG Varley, BJ TI First observation of excited states in the neutron-rich nucleus Te-138 SO EUROPEAN PHYSICAL JOURNAL A LA English DT Article ID ISOTOPES AB The very neutron-rich nucleus Te-138 produced in the spontaneous fission of Cm-248 has been investigated using the EUROGAM II gamma-ray multidetector array. The excited states of 138Te observed for the first time indicate that the region of ground state deformation beyond the doubly magic nucleus Sn-132 has vet not been reached. C1 Inst Rech Subatom, CNRS, UMR 7500, IN2P3, F-67037 Strasbourg, France. Univ Strasbourg 1, F-67037 Strasbourg, France. Univ Warsaw, Inst Expt Phys, PL-00681 Warsaw, Poland. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Manchester, Dept Phys & Astron, Manchester M13 9PL, Lancs, England. Jagiellonian Univ, Dept Nucl Phys, PL-30059 Krakow, Poland. RP Hoellinger, F (reprint author), Inst Rech Subatom, CNRS, UMR 7500, IN2P3, F-67037 Strasbourg, France. NR 11 TC 9 Z9 9 U1 0 U2 0 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 DEC PY 1999 VL 6 IS 4 BP 375 EP 376 DI 10.1007/s100500050357 PG 2 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 272UC UT WOS:000084668500003 ER PT J AU Back, T Cederwall, B Wyss, R Johnson, A Cederkall, J Devlin, M Elson, J LaFosse, DR Lerma, F Sarantites, DG Clark, RM Fallon, P Lee, IY Macchiavelli, AO Macleod, RW AF Back, T Cederwall, B Wyss, R Johnson, A Cederkall, J Devlin, M Elson, J LaFosse, DR Lerma, F Sarantites, DG Clark, RM Fallon, P Lee, IY Macchiavelli, AO Macleod, RW TI Observation of superdeformed states in Mo-88 SO EUROPEAN PHYSICAL JOURNAL A LA English DT Article ID QUADRUPOLE-MOMENT MEASUREMENT; DEFORMED INTRUDER BANDS; MASS REGION; TRANSITIONS; NUCLEI AB High-spin states in Mo-88 were studied using the GAMMASPHERE germanium detector array in conjunction with the MICROBALL CsI(TI) charged-particle detector system. Three gamma-ray cascades with dynamic moments of inertia showing similar characteristics to superdeformed rotational bands observed in the neighbouring A = 80 region have been identified and assigned to the nucleus Mo-88. The quadrupole moment of the strongest band, deduced by the Residual Doppler Shift Method, corresponds to a quadrupole deformation of beta(2) approximate to 0.6. This confirms the superdeformed nature of this band. The experimental data are interpreted in the framework of total routhian surface calculations. All three hands are assigned to two-quasi-particle proton configurations at superdeformed shape. C1 Royal Inst Technol, Dept Phys, S-10405 Stockholm, Sweden. Washington Univ, Dept Chem, St Louis, MO 63130 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Back, T (reprint author), Royal Inst Technol, Dept Phys, S-10405 Stockholm, Sweden. RI Cederwall, Bo/M-3337-2014; Devlin, Matthew/B-5089-2013; OI Cederwall, Bo/0000-0003-1771-2656; Devlin, Matthew/0000-0002-6948-2154; Back, Torbjorn/0000-0003-1996-0805 NR 32 TC 8 Z9 8 U1 0 U2 0 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 DEC PY 1999 VL 6 IS 4 BP 391 EP 397 DI 10.1007/s100500050361 PG 7 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 272UC UT WOS:000084668500007 ER PT J AU Niemoller, T Ichikawa, N Frello, T Hunnefeld, H Andersen, NH Uchida, S Schneider, JR Tranquada, JM AF Niemoller, T Ichikawa, N Frello, T Hunnefeld, H Andersen, NH Uchida, S Schneider, JR Tranquada, JM TI Charge stripes seen with X-rays in La1.45Nd0.4Sr0.15CuO4 SO EUROPEAN PHYSICAL JOURNAL B LA English DT Article ID INCOMMENSURATE MAGNETIC FLUCTUATIONS; SUPERCONDUCTIVITY; LA2-XSRXCUO4; ORDER; LA1.6-XND0.4SRXCUO4; LA2-XBAXCUO4; YBA2CU3O6.6; TEMPERATURE AB Superstructure reflections due to the ordering of holes into stripes in La1.45Nd0.4Sr0.15CuO4 have been studied with high energy X-ray diffraction. These reflections have been observed clearly for the first time in a sample which is superconducting at low temperatures (T-c similar to 10 K). The stripe peaks vanish above 62(5)X whereas the magnetic signal of the stripe ordering which has been seen with neutrons before is already suppressed at similar to 45 K. Our results confirm that the ordering of spins and holes is driven by the charges as it is found in the case of La1.6-xNd0.4SrxCuO4 at the doping level of x = 0.12. C1 DESY, Hamburger Synchrontronstschlungslab HASYLAB, D-22603 Hamburg, Germany. Univ Tokyo, Dept Supercond, Bunkyo Ku, Tokyo 1138656, Japan. Riso Natl Lab, Condensed Matter Phys & Chem Dept, DK-4000 Roskilde, Denmark. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Niemoller, T (reprint author), DESY, Hamburger Synchrontronstschlungslab HASYLAB, Notkestr 85, D-22603 Hamburg, Germany. RI Tranquada, John/A-9832-2009; Andersen, Niels/A-3872-2012 OI Tranquada, John/0000-0003-4984-8857; NR 24 TC 40 Z9 40 U1 0 U2 3 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1434-6028 J9 EUR PHYS J B JI Eur. Phys. J. B PD DEC PY 1999 VL 12 IS 4 BP 509 EP 513 DI 10.1007/s100510051032 PG 5 WC Physics, Condensed Matter SC Physics GA 271WX UT WOS:000084618700006 ER PT J AU Breitweg, J Chekanov, S Derrick, R Krakauer, D Magill, S Musgrave, B Pellegrino, A Repond, J Stanek, R Yoshida, R Mattingly, MCK Abbiendi, G Anselmo, F Antonioli, P Bari, G Basile, M Bellagamba, L Boscherini, D Bruni, A Bruni, G Romeo, GC 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 Hartmann, H Heinloth, K Heinz, L Hilger, E Jakob, HP Kappes, A Katz, UF Kerger, R Paul, E Pfeiffer, R Rautenberg, J Schnurbusch, H Stifutkin, A Tandler, J Weber, A Wieber, H Bailey, DS Barret, O Cottingham, WN Foster, B Heath, GP Heath, HF McFall, JD Piccioni, D Scott, J Tapper, RJ Capua, M Mastroberardino, A Schioppa, M Susinno, G Jeoung, HY Kim, JY Lee, JH Lim, IT Ma, KJ Pac, MY Caldwell, A Cartiglia, N Jing, Z Liu, W Mellado, B Parsons, JA Ritz, S Sacchi, R Sampson, S Sciulli, F Zhu, Q Borzemski, P Chwastowski, J Eskreys, A Figiel, J Klimek, K Olkiewicz, K Przybycien, MB Zawiejski, L Adamczyk, L Bednarek, B Jelen, K Kisielewska, D Kowal, AM Kowalski, T Przybycien, M Rulikowska-Zarebska, E Suszycki, L Zajac, J Dulinski, Z Kotanski, A Bauerdick, LAT Behrens, U Bienlein, JK Burgard, C Desler, K Drews, G Fox-Murphy, A Fricke, U Goebel, F Gottlicher, P Graciani, R Haas, T Hain, W Hartner, GF Hasell, D Hebbel, K Johnson, KF Kasemann, M Koch, W Kotz, U Kowalski, H Lindemann, L Lohr, B Martinez, M Milewski, J Milite, M Monteiro, T Moritz, M Notz, D Pelucchi, F Piotrzkowski, K Rohde, M Saull, PRB Savin, AA Schneekloth, U Schwarzer, O Selonke, F Sievers, M Stonjek, S Tassi, E Wolf, G Wollmer, U Youngman, C Zeuner, W Burow, BD Coldewey, C Grabosch, HJ Viani, ALD Meyer, A Monig, K Schlenstedt, S Straub, PB Barbagli, G Gallo, E Pelfer, P Maccarrone, G Votano, L Bamberger, A Eisenhardt, S Markun, P Raach, H Wolfle, S Brook, NH Bussey, PJ Doyle, AT Lee, SW Macdonald, N McCance, GJ Saxon, DH Sinclair, LE Skillicorn, IO Strickland, E Waugh, R Bohnet, I Gendner, N Holm, U Meyer-Larsen, A Salehi, H Wick, K Garfagnini, A Gialas, I Gladilin, LK Kcira, D Klanner, R Lohrmann, E Poelz, G Zetsche, F Bacon, TC Cole, JE Howell, G Lamberti, L Long, KR Miller, DB Prinias, A Sedgbeer, JK Sideris, D Tapper, AD Walker, R Mallik, U Wang, SM Cloth, P Filges, D Ishii, T Kuze, M Suzuki, I Tokushuku, K Yamada, S Yamauchi, K Yamazaki, Y Ahn, SH An, SH Hong, SJ Lee, SB Nam, SW Park, SK Lim, H Park, IH Son, D Barreiro, F Fernandez, JP Garcia, G Glasman, C Hernandez, JM Labarga, L del Peso, J Puga, J Redondo, I Terron, J Corriveau, F Hanna, DS Hartmann, J Murray, WN Ochs, A Padhi, S Riveline, M Stairs, DG St-Laurent, M Wing, M Tsurugai, T Bashkirov, V Dolgoshein, BA Bashindzhagyan, GL Ermolov, PF Golubkov, YA Khein, LA Korotkova, NA Korzhavina, 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 Velthuis, JJ 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 Blaikley, HE Boogert, S Cashmore, RJ Cooper-Sarkar, AM Devenish, RCE Edmonds, JK Grosse-Knetter, J Harnew, N Matsushita, T Noyes, VA Quadt, A Ruske, O Sutton, MR Walczak, R Waters, DS Bertolin, A Brugnera, R Carlin, R Dal Corso, F Dondana, S Dosselli, U Dusini, S Limentani, S Morandin, M Posocco, M Stanco, L Stroili, R Voci, V Iannotti, L Oh, BY Okrasinski, JR Toothacker, WS Whitmore, JJ Iga, Y D'Agostini, G Marini, G Nigro, A Raso, M Cormack, C Hart, JC McCubbin, NA Shah, TP Epperson, D Heusch, C Sadrozinski, HFW Seiden, A Wichmann, R Williams, DC Pavel, N Abramowicz, H Dagan, S Kananov, S Kreisel, A Levy, A Schechter, A Abe, T Fusayasu, T Inuzuka, M Nagano, K Umemori, K Yamashita, T Hamatsu, R Hirose, T Homma, K Kitamura, S Nishimura, T Arneodo, M Cirio, R Costa, M Ferrero, MI Maselli, S Monaco, V Peroni, C Petrucci, MC Ruspa, M Solano, A Staiano, A Dardo, M Bailey, DC Fagerstroem, CP Galea, R Koop, T Levman, GM Martin, JF Orr, RS Polenz, S Sabetfakhri, A Simmons, D Butterworth, JM Catterall, CD Hayes, ME Heaphy, EA Jones, TW Lane, JB Ciborowski, J Grzelak, G Nowak, RJ Pawlak, JM Pawlak, R Smalska, B Tymieniecka, T Wroblewski, AK Zakrzewski, JA Zarnecki, AF Adamus, M Gadaj, T Deppe, O Eisenberg, Y Hochman, D Karshon, U Badgett, WF Chapin, D Cross, R Foudas, C Mattingly, S Reeder, DD Smith, WH Vaiciulis, A Wildschek, T Wodarczyk, M Deshpande, A Dhawan, S Hughes, VW Bhadra, S Frisken, WR Hall-Wilton, R Khakzad, M Menary, S Schmidke, WB AF Breitweg, J Chekanov, S Derrick, R Krakauer, D Magill, S Musgrave, B Pellegrino, A Repond, J Stanek, R Yoshida, R Mattingly, MCK Abbiendi, G Anselmo, F Antonioli, P Bari, G Basile, M Bellagamba, L Boscherini, D Bruni, A Bruni, G Romeo, GC 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 Hartmann, H Heinloth, K Heinz, L Hilger, E Jakob, HP Kappes, A Katz, UF Kerger, R Paul, E Pfeiffer, R Rautenberg, J Schnurbusch, H Stifutkin, A Tandler, J Weber, A Wieber, H Bailey, DS Barret, O Cottingham, WN Foster, B Heath, GP Heath, HF McFall, JD Piccioni, D Scott, J Tapper, RJ Capua, M Mastroberardino, A Schioppa, M Susinno, G Jeoung, HY Kim, JY Lee, JH Lim, IT Ma, KJ Pac, MY Caldwell, A Cartiglia, N Jing, Z Liu, W Mellado, B Parsons, JA Ritz, S Sacchi, R Sampson, S Sciulli, F Zhu, Q Borzemski, P Chwastowski, J Eskreys, A Figiel, J Klimek, K Olkiewicz, K Przybycien, MB Zawiejski, L Adamczyk, L Bednarek, B Jelen, K Kisielewska, D Kowal, AM Kowalski, T Przybycien, M Rulikowska-Zarebska, E Suszycki, L Zajac, J Dulinski, Z Kotanski, A Bauerdick, LAT Behrens, U Bienlein, JK Burgard, C Desler, K Drews, G Fox-Murphy, A Fricke, U Goebel, F Gottlicher, P Graciani, R Haas, T Hain, W Hartner, GF Hasell, D Hebbel, K Johnson, KF Kasemann, M Koch, W Kotz, U Kowalski, H Lindemann, L Lohr, B Martinez, M Milewski, J Milite, M Monteiro, T Moritz, M Notz, D Pelucchi, F Piotrzkowski, K Rohde, M Saull, PRB Savin, AA Schneekloth, U Schwarzer, O Selonke, F Sievers, M Stonjek, S Tassi, E Wolf, G Wollmer, U Youngman, C Zeuner, W Burow, BD Coldewey, C Grabosch, HJ Viani, ALD Meyer, A Monig, K Schlenstedt, S Straub, PB Barbagli, G Gallo, E Pelfer, P Maccarrone, G Votano, L Bamberger, A Eisenhardt, S Markun, P Raach, H Wolfle, S Brook, NH Bussey, PJ Doyle, AT Lee, SW Macdonald, N McCance, GJ Saxon, DH Sinclair, LE Skillicorn, IO Strickland, E Waugh, R Bohnet, I Gendner, N Holm, U Meyer-Larsen, A Salehi, H Wick, K Garfagnini, A Gialas, I Gladilin, LK Kcira, D Klanner, R Lohrmann, E Poelz, G Zetsche, F Bacon, TC Cole, JE Howell, G Lamberti, L Long, KR Miller, DB Prinias, A Sedgbeer, JK Sideris, D Tapper, AD Walker, R Mallik, U Wang, SM Cloth, P Filges, D Ishii, T Kuze, M Suzuki, I Tokushuku, K Yamada, S Yamauchi, K Yamazaki, Y Ahn, SH An, SH Hong, SJ Lee, SB Nam, SW Park, SK Lim, H Park, IH Son, D Barreiro, F Fernandez, JP Garcia, G Glasman, C Hernandez, JM Labarga, L del Peso, J Puga, J Redondo, I Terron, J Corriveau, F Hanna, DS Hartmann, J Murray, WN Ochs, A Padhi, S Riveline, M Stairs, DG St-Laurent, M Wing, M Tsurugai, T Bashkirov, V Dolgoshein, BA Bashindzhagyan, GL Ermolov, PF Golubkov, YA Khein, LA Korotkova, NA Korzhavina, 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 Velthuis, JJ 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 Blaikley, HE Boogert, S Cashmore, RJ Cooper-Sarkar, AM Devenish, RCE Edmonds, JK Grosse-Knetter, J Harnew, N Matsushita, T Noyes, VA Quadt, A Ruske, O Sutton, MR Walczak, R Waters, DS Bertolin, A Brugnera, R Carlin, R Dal Corso, F Dondana, S Dosselli, U Dusini, S Limentani, S Morandin, M Posocco, M Stanco, L Stroili, R Voci, V Iannotti, L Oh, BY Okrasinski, JR Toothacker, WS Whitmore, JJ Iga, Y D'Agostini, G Marini, G Nigro, A Raso, M Cormack, C Hart, JC McCubbin, NA Shah, TP Epperson, D Heusch, C Sadrozinski, HFW Seiden, A Wichmann, R Williams, DC Pavel, N Abramowicz, H Dagan, S Kananov, S Kreisel, A Levy, A Schechter, A Abe, T Fusayasu, T Inuzuka, M Nagano, K Umemori, K Yamashita, T Hamatsu, R Hirose, T Homma, K Kitamura, S Nishimura, T Arneodo, M Cirio, R Costa, M Ferrero, MI Maselli, S Monaco, V Peroni, C Petrucci, MC Ruspa, M Solano, A Staiano, A Dardo, M Bailey, DC Fagerstroem, CP Galea, R Koop, T Levman, GM Martin, JF Orr, RS Polenz, S Sabetfakhri, A Simmons, D Butterworth, JM Catterall, CD Hayes, ME Heaphy, EA Jones, TW Lane, JB Ciborowski, J Grzelak, G Nowak, RJ Pawlak, JM Pawlak, R Smalska, B Tymieniecka, T Wroblewski, AK Zakrzewski, JA Zarnecki, AF Adamus, M Gadaj, T Deppe, O Eisenberg, Y Hochman, D Karshon, U Badgett, WF Chapin, D Cross, R Foudas, C Mattingly, S Reeder, DD Smith, WH Vaiciulis, A Wildschek, T Wodarczyk, M Deshpande, A Dhawan, S Hughes, VW Bhadra, S Frisken, WR Hall-Wilton, R Khakzad, M Menary, S Schmidke, WB CA ZEUS Collaboration TI Measurement of high-Q(2) neutral-current e(+)p deep inelastic scattering cross-sections at HERA SO EUROPEAN PHYSICAL JOURNAL C LA English DT Article ID DEUTERON STRUCTURE FUNCTIONS; HIGH STATISTICS MEASUREMENT; CENTRAL TRACKING DETECTOR; ZEUS BARREL CALORIMETER; MONTE-CARLO GENERATOR; LARGE RAPIDITY GAP; PARTON DISTRIBUTIONS; MUON SCATTERING; GLOBAL ANALYSIS; LEADING ORDER AB The e(+)p neutral-current deep inelastic scattering differential cross-sections d sigma/dQ(2), for Q(2) > 400 GeV2, d sigma/dx and d sigma/dy, for Q(2) > 400, 2500 and 10000 GeV2, have been measured with the ZEUS detector at HERA. The data sample of 47.7 pb(-1) was collected at a center-of-mass energy of 300 GeV. The cross-section, d sigma/dQ(2), falls by six orders of magnitude between Q(2) = 400 and 40000 GeV2. The predictions of the Standard Model are in very good agreement with the data. Complementing the observations of time-like Z(0) contributions to fermion-antifermion annihilation! the data provide direct evidence for the presence of Z(0) exchange in the space-like region explored by deep inelastic scattering. 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, South Korea. Columbia Univ, Nevis Labs, Irvington, NY USA. Inst Nucl Phys, Krakow, Poland. Acad Min & Met, Fac Phys & Nucl Tech, Krakow, Poland. Jagiellonian Univ, Dept Phys, Krakow, Poland. DESY, D-2000 Hamburg, Germany. DESY, 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 Exp 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. Kyungpook Natl Univ, Taegu 702701, 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. NIKHEF H, NL-1009 DB Amsterdam, Netherlands. Univ Amsterdam, 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, I-00185 Rome, Italy. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. Univ Siegen, Fachbereich Phys, D-5900 Siegen, Germany. Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, Sch Phys, IL-69978 Tel Aviv, Israel. Univ Tokyo, Dept Phys, Tokyo 113, Japan. Tokyo Metropolitan Univ, Dept Phys, Tokyo, Japan. Univ Turin, Dipartimento Fis Sperimentale, Turin, Italy. Ist Nazl Fis Nucl, I-10125 Turin, Italy. Univ Turin, Fac Sci 2, Turin, Italy. INFN Alessandria, Alessandria, Italy. Univ Toronto, Dept Phys, Toronto, ON, Canada. UCL, Dept Phys & Astron, London, England. Warsaw Univ, Inst Phys Expt, 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, Toronto, ON M3J 2R7, Canada. IROE, Florence, Italy. RP Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Solomin, Anatoly/C-3072-2016; dusini, stefano/J-3686-2012; Graciani Diaz, Ricardo/I-5152-2016; Capua, Marcella/A-8549-2015; 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; Gladilin, Leonid/B-5226-2011; Morandin, Mauro/A-3308-2016 OI dusini, stefano/0000-0002-1128-0664; Graciani Diaz, Ricardo/0000-0001-7166-5198; Castellini, Guido/0000-0002-0177-0643; Capua, Marcella/0000-0002-2443-6525; 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; Gladilin, Leonid/0000-0001-9422-8636; Morandin, Mauro/0000-0003-4708-4240 NR 70 TC 62 Z9 62 U1 0 U2 2 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1434-6044 EI 1434-6052 J9 EUR PHYS J C JI Eur. Phys. J. C PD DEC PY 1999 VL 11 IS 3 BP 427 EP 445 DI 10.1007/s100520050645 PG 19 WC Physics, Particles & Fields SC Physics GA 266TV UT WOS:000084317100003 ER PT J AU Asmis, KR Taylor, TR Neumark, DM AF Asmis, KR Taylor, TR Neumark, DM TI Anion photoelectron spectroscopy of small boron nitride clusters: adiabatic detachment energies and vibrational frequencies of low-lying electronic states in B2N and B3N SO EUROPEAN PHYSICAL JOURNAL D LA English DT Article; Proceedings Paper CT 9th International Symposium of Small Particles and Inorganic Clusters CY SEP 01-05, 1998 CL LAUSANNE, SWITZERLAND SP Swiss Fed Inst Technol, Dept Phys, Swiss Natl Sci Fdn, Swiss Acad Sci, Univ Lausanne, Schweizer Gesell Nanowissensch & Nanotechn ID HARMONIC VIBRATIONS; NITROGEN CLUSTERS; BN; TRANSITION; ENERGETICS; PLASMA; MATRIX; ATOMS; ARGON AB Vibrationally resolved photoelectron spectra of B2N- and B3N- at 266 nm are reported. The spectroscopy of B3N was studied experimentally for the first time. The spectra allow us to determine adiabatic detachment energies and vibrational frequencies for several low-lying electronic states of the neutral species. Both ground state anions are shown to have linear geometries. For B2N- transitions to two electronic states of the neutral are observed. The electron affinity of B2N ((X) over tilde(2)Sigma(u)(+)) is 3.098 +/- 0.010 eV. The term energy of the electronically excited state ((A) over tilde(2)Sigma(g)(+)) is 0.785 eV. Transitions to three electronic states of B3N are observed, of which the first two show vibrational structure. The adiabatic detachment energies for these two states are 2.919 eV and 3.062 eV. Preliminary calculations indicate that the photodetachment transition between the electronic ground states of B3N- and B3N is spin-forbidden and therefore not observed in our spectra. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Asmis, KR (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Asmis, Knut/N-5408-2014; Neumark, Daniel/B-9551-2009 OI Asmis, Knut/0000-0001-6297-5856; Neumark, Daniel/0000-0002-3762-9473 NR 25 TC 13 Z9 15 U1 0 U2 4 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1434-6060 J9 EUR PHYS J D JI Eur. Phys. J. D PD DEC PY 1999 VL 9 IS 1-4 SI SI BP 257 EP 261 DI 10.1007/s100530050436 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 319AP UT WOS:000087317100050 ER PT J AU Taylor, TR Asmis, KR Gomez, H Neumark, DM AF Taylor, TR Asmis, KR Gomez, H Neumark, DM TI Vibrationally resolved anion photoelectron spectra of the low-lying electronic states of GaP2-, Ga2P-, and Ga2P3- SO EUROPEAN PHYSICAL JOURNAL D LA English DT Article; Proceedings Paper CT 9th International Symposium of Small Particles and Inorganic Clusters CY SEP 01-05, 1998 CL LAUSANNE, SWITZERLAND SP Swiss Fed Inst Technol, Dept Phys, Swiss Natl Sci Fdn, Swiss Acad Sci, Univ Lausanne, Schweizer Gesell Nanowissensch & Nanotechn ID GALLIUM-PHOSPHIDE; SPECTROSCOPY; CLUSTERS AB Anion photoelectron spectra of GaP2-, Ga2P-, and Ga2P3- have been taken at photodetachment wavelengths of 266 nm (4.657 eV), 355 nm (3.493 eV), 416 nm (2.977 eV), and 498 nm (2.491 eV). Using this variety of wavelengths has allowed us to vibrationally resolve the low-lying electronic states of these species. We report electron affinities, term values, and vibrational frequencies of the corresponding neutral and anion states where possible. Results are in qualitative agreement with current ab initio studies. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Taylor, TR (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Asmis, Knut/N-5408-2014; Neumark, Daniel/B-9551-2009 OI Asmis, Knut/0000-0001-6297-5856; Neumark, Daniel/0000-0002-3762-9473 NR 13 TC 26 Z9 27 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1434-6060 J9 EUR PHYS J D JI Eur. Phys. J. D PD DEC PY 1999 VL 9 IS 1-4 SI SI BP 317 EP 321 DI 10.1007/s100530050447 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 319AP UT WOS:000087317100061 ER PT J AU Gutierrez, E Powell, RD Furuya, FR Hainfeld, JF Schaaff, TG Shafigullin, MN Stephens, PW Whetten, RL AF Gutierrez, E Powell, RD Furuya, FR Hainfeld, JF Schaaff, TG Shafigullin, MN Stephens, PW Whetten, RL TI Greengold, a giant cluster compound of unusual electronic structure SO EUROPEAN PHYSICAL JOURNAL D LA English DT Article; Proceedings Paper CT 9th International Symposium of Small Particles and Inorganic Clusters CY SEP 01-05, 1998 CL LAUSANNE, SWITZERLAND SP Swiss Fed Inst Technol, Dept Phys, Swiss Natl Sci Fdn, Swiss Acad Sci, Univ Lausanne, Schweizer Gesell Nanowissensch & Nanotechn ID STABILIZED METAL-CLUSTERS; GOLD CLUSTERS; SPECTRA; MOLECULES; BULK AB We report the isolation of a previously elusive giant gold-cluster compound with unusual electronic structure and excellent solid-state ordering properties. Greengold is a water-soluble Au:PR3 compound (R=p-C6H4-CONHCH3) formed in high yield in the solution-phase reduction of R3PAuCl. Following chromatographic isolation, it has been investigated by electron microscopy (STEM), optical spectroscopy, mass spectrometry (MALDI), and X-ray diffraction, from which emerges a consistent picture of Greengold's intrinsic characteristics as (i) a single compound of similar to 22 000 amu molecular weight, containing a strongly bound globular metal core of mass 14800 (AU(75), 1.3-nm equivalent diameter); (ii) a highly ordered solid, exhibiting diffraction through 21 orders of a 2.47-nm spacing; and (iii) a carrier of a highly structured optical absorption across the entire visible and near-infrared spectrum (to similar to 1.0 eV), including relative transparency in the blue and yellow regions, giving rise to its eponymous green tint. C1 Nanoprobes Inc, Stony Brook, NY 11790 USA. Brookhaven Natl Lab, Div Biol, Stony Brook, NY 11794 USA. Georgia Inst Technol, Sch Phys & Chem, Atlanta, GA 30332 USA. SUNY Stony Brook, Dept Phys, Stony Brook, NY 11794 USA. RP Gutierrez, E (reprint author), Nanoprobes Inc, Stony Brook, NY 11790 USA. NR 26 TC 38 Z9 38 U1 1 U2 5 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1434-6060 J9 EUR PHYS J D JI Eur. Phys. J. D PD DEC PY 1999 VL 9 IS 1-4 SI SI BP 647 EP 651 DI 10.1007/s100530050519 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 319AP UT WOS:000087317100133 ER PT J AU Cantu-Paz, E Goldberg, DE AF Cantu-Paz, Erick Goldberg, David E. TI On the Scalability of Parallel Genetic Algorithms SO EVOLUTIONARY COMPUTATION LA English DT Article DE Master-slave genetic algorithms; multiple demes; island model; deme size; topology; migration rate; bounding cases AB This paper examines the scalability of several types of parallel genetic algorithms (GAs). The objective is to determine the optimal number of processors that can be used by each type to minimize the execution time. The first part of the paper considers algorithms with a single population. The investigation focuses on an implementation where the population is distributed to several processors, but the results are applicable to more common master-slave implementations, where the population is entirely stored in a master processor and multiple slaves are used to evaluate the fitness. The second part of the paper deals with parallel GAs with multiple populations. It first considers a bounding case where the connectivity, the migration rate, and the frequency of migrations are set to their maximal values. Then, arbitrary regular topologies with lower migration rates are considered and the frequency of migrations is set to its lowest value. The investigation is mainly theoretical, but experimental evidence with an additively-decomposable function is included to illustrate the accuracy of the theory. In all cases, the calculations show that the optimal number of processors that minimizes the execution time is directly proportional to the square root of the population size and the fitness evaluation time. Since these two factors usually increase as the domain becomes more difficult, the results of the paper suggest that parallel GAs can integrate large numbers of processors and significantly reduce the execution time of many practical applications. C1 [Cantu-Paz, Erick] Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, Livermore, CA 94551 USA. [Goldberg, David E.] Univ Illinois, Dept Gen Engn, Urbana, IL 61801 USA. [Cantu-Paz, Erick] Univ Illinois, Dept Comp Sci, Chicago, IL 60680 USA. RP Cantu-Paz, E (reprint author), Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, POB 808,L-551, Livermore, CA 94551 USA. EM cantupaz@llnl.gov; deg@illigal.ge.uiuc.edu FU Fulbright-Garcia Robles Fellowship; Air Force Office of Scientific Research, Air Force Materiel Command, USAF [F49620-97-1-0050]; US Army Research Laboratory [DAAL01-96-2-003] FX Erick Cantu-Paz was partially supported by a Fulbright-Garcia Robles Fellowship. The work was sponsored by the Air Force Office of Scientific Research, Air Force Materiel Command, USAF, under grant number F49620-97-1-0050. Research funding for this project was also provided by a grant from the US Army Research Laboratory Program, Cooperative Agreement DAAL01-96-2-003. The US Government is authorized to reproduce and distribute reprints for governmental purposes notwithstanding any copyright notation thereon. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies and endorsements, either expressed or implied, of the Air Force Office of Scientific Research or the US Government. NR 26 TC 27 Z9 27 U1 0 U2 3 PU MIT PRESS PI CAMBRIDGE PA ONE ROGERS ST, CAMBRIDGE, MA 02142-1209 USA SN 1063-6560 EI 1530-9304 J9 EVOL COMPUT JI Evol. Comput. PD WIN PY 1999 VL 7 IS 4 SI SI BP 429 EP 449 DI 10.1162/evco.1999.7.4.429 PG 21 WC Computer Science, Artificial Intelligence; Computer Science, Theory & Methods SC Computer Science GA V21ZM UT WOS:000208245500006 PM 10578030 ER PT J AU Garland, JL Lehman, RM AF Garland, JL Lehman, RM TI Dilution/extinction of community phenotypic characters to estimate relative structural diversity in mixed communities SO FEMS MICROBIOLOGY ECOLOGY LA English DT Article DE diversity; microbial community; functional richness ID SUBSTRATE UTILIZATION PATTERNS; MICROBIAL COMMUNITIES; BACTERIAL DIVERSITY; EVOLUTION; ECOLOGY AB Recent interest in microbial diversity has led to increased emphasis on the development of appropriate techniques. Structural diversity encompasses the number and distribution of separate or interacting biological entities responsible for a given function within the overall set of functions of a community. This study evaluated an approach for estimating the relative degree of structural diversity in heterotrophic microbial communities by dilution to extinction of community phenotypic traits. Serial dilutions of environmental samples (rhizosphere, stream) were tested for community phenotypic traits (i.e. carbon source respiration). The non-linear relationship between the number of positive responses (i.e. functional richness or R) and inoculum density in each sample dilution (I) fit the simple rectangular hyperbola model, allowing estimation of the maximal richness (R-max) and the inoculum density at half-maximal richness (K-1). The later term appears to be useful in assessing relative structural diversity as evidenced by significantly higher values for communities with higher predicted species diversity. The examination of community functional characteristics across a series of dilutions, particularly in conjunction with other techniques, may be a useful approach for the study of microbial diversity and related ecological parameters such as niche width and metabolic redundancy. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Dynamac Corp, Kennedy Space Ctr, FL 32899 USA. Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Garland, JL (reprint author), Dynamac Corp, Mail Code DYN-3, Kennedy Space Ctr, FL 32899 USA. OI Lehman, Michael/0000-0002-3391-3178 NR 31 TC 44 Z9 50 U1 1 U2 24 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-6496 J9 FEMS MICROBIOL ECOL JI FEMS Microbiol. Ecol. PD DEC PY 1999 VL 30 IS 4 BP 333 EP 343 DI 10.1111/j.1574-6941.1999.tb00661.x PG 11 WC Microbiology SC Microbiology GA 260CT UT WOS:000083932500006 ER PT J AU Zhang, CL Stapleton, RD Zhou, JZ Palumbo, AV Phelps, TJ AF Zhang, CL Stapleton, RD Zhou, JZ Palumbo, AV Phelps, TJ TI Iron reduction by psychotrophic enrichment cultures SO FEMS MICROBIOLOGY ECOLOGY LA English DT Article DE psychrotroph; iron reduction; H-2; organic acid; permafrost; deep marine sediment ID DISSIMILATORY FE(III) REDUCTION; SP-NOV; FE(III)-REDUCING BACTERIA; GEN-NOV; MICROORGANISM; OXIDATION; MANGANESE; RESPIRATION; SUBSURFACE AB Psychrotrophic (<20 degrees C) enrichment cultures from deep Pacific marine sediments and Alaskan tundra permafrost reduced ferric iron when using organic acids or H-2 as electron donors. The representative culture W3-7 from the Pacific sediments grew fastest at 10 degrees C, which was 5-fold faster than at 25 degrees C and more than 40-fold faster than at 4 degrees C. Fe(III) reduction was also the fastest at 10 degrees C, which was 2-fold faster than at 25 degrees C and 12-fold faster than at 4 degrees C. Overall, about 80% of the enrichment cultures exhibited microbial Fe(III) reduction under psychrotrophic conditions. These results indicated that microbial iron reduction is likely widespread in cold natural environments and may play important roles in cycling of iron and organic matter over geological times. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Univ Missouri, Dept Geol Sci, Columbia, MO 65211 USA. RP Zhou, JZ (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. RI Palumbo, Anthony/A-4764-2011; phelps, tommy/A-5244-2011 OI Palumbo, Anthony/0000-0002-1102-3975; NR 25 TC 13 Z9 14 U1 1 U2 12 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-6496 J9 FEMS MICROBIOL ECOL JI FEMS Microbiol. Ecol. PD DEC PY 1999 VL 30 IS 4 BP 367 EP 371 DI 10.1111/j.1574-6941.1999.tb00664.x PG 5 WC Microbiology SC Microbiology GA 260CT UT WOS:000083932500009 ER PT J AU Li, D Ma, M AF Li, D Ma, M TI Nanoporous polymers: New nanosponge absorbent media SO FILTRATION & SEPARATION LA English DT Article AB Researchers at the Los Alamos National Laboratory, USA have developed a completely new class of organic nanoporous Polymers with narrow pore size distributions using cyclodextrins as basic building blocks. DeQuan Li and Min Ma provide more details of the polymers that are proving very efficient in absorbing organic molecules in water. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Li, D (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 0 TC 15 Z9 15 U1 1 U2 9 PU ELSEVIER ADVANCED TECHNOLOGY PI OXFORD PA OXFORD FULFILLMENT CENTRE THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0015-1882 J9 FILTR SEPARAT JI Filtr. Sep. PD DEC PY 1999 VL 36 IS 10 BP 26 EP 28 PG 3 WC Engineering, Chemical SC Engineering GA 266EL UT WOS:000084287600003 ER PT J AU Isbell, DT Gusev, AI Taranenko, NI Chen, CH Hercules, DM AF Isbell, DT Gusev, AI Taranenko, NI Chen, CH Hercules, DM TI Analysis of nucleotides directly from TLC plates using MALDI-MS detection SO FRESENIUS JOURNAL OF ANALYTICAL CHEMISTRY LA English DT Article ID THIN-LAYER CHROMATOGRAPHY; ASSISTED LASER-DESORPTION; IONIZATION MASS-SPECTROMETRY; CARCINOGEN-DNA ADDUCTS; MODIFIED OLIGONUCLEOTIDES; FAST-EVAPORATION; MATRIX; SENSITIVITY; RESOLUTION; OLIGODEOXYRIBONUCLEOTIDES AB The methodology for the detection of picogram quantities of nucleotides directly from TLC plates without the use of radioactive labeling has been developed. The method couples thin-layer chromatography (TLC) separation with matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) detection. The TLC/MALDI coupling protocol was studied and optimized for the separation and detection of deoxyribonucleotides. Several ammonia based solvents were examined as potential extraction solvents for the TLC/MALDI coupling protocol. It was found that in order to obtain maximum TLC/MALDI signal intensity and minimal analyte spreading, the extraction solvent should produce R-f-values for the analytes in the range of 0.3-0.4. R-f-values above this range led to extensive analyte spreading and those below this range resulted in poor extraction. Various MALDI matrices and co-matrices were investigated, the best results were obtained using 2',4',6'-trihydroxyacetophenone (THA) as a matrix. The extraction solvent chosen was an ammonium hydroxide/methanol (100 mM/30%, R-f = 0.28-0.38) solvent system which was found to provide the best sensitivity, minimal lateral spreading and excellent matrix transfer. Using the optimized coupling protocol, the detection limits for the deoxyribonucleotide monophosphates were established at or better than 10 picograms. C1 Vanderbilt Univ, Dept Chem, Nashville, TN 37235 USA. Oak Ridge Natl Lab, Oak Ridge, TN USA. RP Hercules, DM (reprint author), Vanderbilt Univ, Dept Chem, Box 1583, Nashville, TN 37235 USA. NR 47 TC 19 Z9 19 U1 1 U2 7 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0937-0633 J9 FRESEN J ANAL CHEM JI Fresenius J. Anal. Chem. PD DEC PY 1999 VL 365 IS 7 BP 625 EP 630 DI 10.1007/s002160051534 PG 6 WC Chemistry, Analytical SC Chemistry GA 262QX UT WOS:000084078900011 ER PT J AU Smith, DL Meadows, JW Gomes, IC AF Smith, DL Meadows, JW Gomes, IC TI Cross-sections for hydrogen production from vanadium in a fusion neutron environment SO FUSION ENGINEERING AND DESIGN LA English DT Article DE fusion-reactor technology; fusion neutrons; hydrogen gas production; radiation damage; vanadium; nuclear-model calculations; evaluated cross-sections; experimental neutron cross-sections ID ALPHA-PARTICLES AB The experimental and evaluated information available from the literature on neutron cross-sections for hydrogen production from vanadium in a fusion neutron environment has been reviewed. Discrepancies in these results were identified and likely explanations for their existence are suggested. Nuclear-model calculations were performed using the statistical pre-compound code GNASH. The results from this analysis are compared with existing information. Revised cross-section values for use in contemporary calculations of hydrogen gas production in fusion reactors are recommended. The impact of these revisions on other neutron cross-sections of vanadium that affect neutronic calculations for fusion reactors is also discussed. Finally, integral calculations of hydrogen production were performed for a typical fusion reactor using the present recommended cross-section values. It was found that this alternative cross-section set leads to a calculated value of hydrogen production at the fusion reactor first wall which is a factor of 3.25 smaller than obtained from similar calculations that employ evaluated cross-sections from the ENDF/B-6.4 Library exclusively. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Argonne Natl Lab, Technol Dev Div, Argonne, IL 60439 USA. RP Smith, DL (reprint author), Argonne Natl Lab, Technol Dev Div, TD-360-L106,9700 S Cass Ave, Argonne, IL 60439 USA. NR 57 TC 3 Z9 3 U1 0 U2 1 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 DEC PY 1999 VL 47 IS 1 BP 61 EP 84 DI 10.1016/S0920-3796(99)00075-7 PG 24 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 261NM UT WOS:000084015300004 ER PT J AU Andrew, P Brennan, PD Coad, JP Ehrenberg, J Gadeberg, M Gibson, A Hillis, DL How, J Jarvis, ON Jensen, H Lasser, R Marcus, F Monk, R Morgan, P Orchard, J Peacock, A Pearce, R Pick, M Rossi, A Schild, P Schunke, B Stork, D AF Andrew, P Brennan, PD Coad, JP Ehrenberg, J Gadeberg, M Gibson, A Hillis, DL How, J Jarvis, ON Jensen, H Lasser, R Marcus, F Monk, R Morgan, P Orchard, J Peacock, A Pearce, R Pick, M Rossi, A Schild, P Schunke, B Stork, D TI Tritium retention and clean-up in JET SO FUSION ENGINEERING AND DESIGN LA English DT Article DE JET; torus; tritium retention ID FUSION TEST REACTOR; 1ST WALL; DEUTERIUM; CARBON; BERYLLIUM; RELEASE AB During 1997 JET operation with D-T plasmas, 35 g of tritium were introduced into the torus, mainly by gas puffing. It was found that during this period, the torus tritium inventory would accumulate at a rate of about 40% of the input. After tritium operation ceased,;he experimental program continued with deuterium- and hydrogen-fuelled experiments, during which time the tritium inventory decreased to about 17% of the total input. Techniques aimed at detritiation of the torus included methods using deuterium gas (such as deuterium pulsing) which were used in the middle of the experimental campaign, and methods which could adversely affect the torus vacuum conditions (such as air purges) which were reserved for the period after the experimental campaign. Whilst it was found that the plasma tritium fraction could be reduced to below the 1% level in a few days, the tritium inventory reached a virtually steady level of about 6 g by the end of the campaign. (C) 1999 JET Joint Undertaking. Published by Elsevier Science S.A. All rights reserved. C1 Jet Joint Undertaking, Abingdon OX14 3EA, Oxon, England. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Andrew, P (reprint author), Univ Wisconsin, Dept Phys, 1150 Univ Ave, Madison, WI 53706 USA. NR 38 TC 116 Z9 117 U1 2 U2 9 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 DEC PY 1999 VL 47 IS 2-3 BP 233 EP 245 DI 10.1016/S0920-3796(99)00084-8 PG 13 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 268TK UT WOS:000084431500007 ER PT J AU Maas, AC Andrew, P Coad, P Edwards, A Ehrenberg, J Gibson, A Gunther, K Harbour, P von Hellermann, MG Hillis, D Howman, A Jarvis, ON Junger, JF Konig, RWT Lingertat, J Loughlin, MJ Morgan, PD Orchard, J Sadler, G Stamp, MF Wilson, CH AF Maas, AC Andrew, P Coad, P Edwards, A Ehrenberg, J Gibson, A Gunther, K Harbour, P von Hellermann, MG Hillis, D Howman, A Jarvis, ON Junger, JF Konig, RWT Lingertat, J Loughlin, MJ Morgan, PD Orchard, J Sadler, G Stamp, MF Wilson, CH TI Diagnostic experience during deuterium-tritium experiments in JET, techniques and measurements SO FUSION ENGINEERING AND DESIGN LA English DT Article DE diagnostic techniques; diagnostic systems; deuterium; tritium ID PLASMAS AB During 1997 JET was operated for an extensive period using a D-T mixture (DTE1). Changes in the design and operation of diagnostic systems made over the years in preparation for this phase are described. A number of diagnostic techniques have been deployed to measure the deuterium and tritium content of the plasma during DTE1 and their results an compared. All diagnostics with a direct vacuum interface with the main vessel have been fitted with tritium compatible pumps and their exhaust gases have been re-routed to the active gas handling plant. All items on the torus which could lead to a significant leak in the event of failure, were required to have double containment. Therefore, all windows, and a majority of bellows and feedthroughs, were designed and installed with a double barrier. Heated fibre hoses were installed to transmit plasma light beyond the biological shield for spectroscopic purposes. Blind fibres and fibre loops were also installed to study the effects of higher neutron fluxes on these fibres. A radiation-hardened video camera was installed to monitor the plasma during the DTE1 discharges. Extra shielding was installed on a number of diagnostics to deal with the higher neutron fluxes during DTE1. The effect of neutron radiation on electronics in the Torus Hall was studied. During DTE1 the tritium fraction was measured at the edge and in the core using several diagnostic methods. High resolution Balmer ct line spectroscopy gave a measurement typical of the plasma edge region. In the JET sub-divertor volume the tritium concentration of the neutral gas was measured using Balmer a spectroscopy of a Penning gauge discharge. Using Neutral Particle Analysis, the tritium concentration was measured typically in a zone 20-40 cm from the plasma edge. Local core measurements of the tritium fraction have been made using active Balmer a charge exchange spectroscopy. The error on this measurement is, however, large, similar to 30%. After the discharge the tritium fraction of the exhaust was measured using the exhaust monitoring system. Using short deuterium neutral injection pulses allowed neutron rate measurements of the tritium concentration in the core region. A further technique used the measured neutron rate and calculated neutron rate from other plasma parameters to determine the tritium concentration. (C) 1999 JET Joint Undertaking, Published by Elsevier Science S.A. All rights reserved. C1 Jet Joint Undertaking, Abingdon OX14 3EA, Oxon, England. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Maas, AC (reprint author), Jet Joint Undertaking, Abingdon OX14 3EA, Oxon, England. EM acm@jet.uk RI shao, chongyun/M-6620-2013 NR 35 TC 20 Z9 22 U1 0 U2 7 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 DEC PY 1999 VL 47 IS 2-3 BP 247 EP 265 DI 10.1016/S0920-3796(99)00085-X PG 19 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 268TK UT WOS:000084431500008 ER PT J AU Peterson, ET Sutherland, R Robinson, DL Chasteen, L Gersh, M Overhauser, J Deaven, LL Moyzis, RK Grady, DL AF Peterson, ET Sutherland, R Robinson, DL Chasteen, L Gersh, M Overhauser, J Deaven, LL Moyzis, RK Grady, DL TI An integrated physical map for the short arm of human chromosome 5 SO GENOME RESEARCH LA English DT Article ID YAC CONTIG MAP; YEAST ARTIFICIAL CHROMOSOMES; RADIATION HYBRID MAP; CHAT CRITICAL REGION; HUMAN-GENOME; DNA-SEQUENCES; X-CHROMOSOME; GENES; LOCALIZATION; DELETIONS AB The short arm of human chromosome 5 contains similar to 48 Mb of DNA and comprises 1.5% of the genome. We have constructed a mega-YAC/ STS map of this region that includes 436 YACs anchored by 216 STSs. By combining and integrating our map with the 5p maps of other groups using the same recombinant DNA library, a comprehensive map was constructed that includes 552 YACs and 504 markers. The YAC map covers >94% of 5p in four YAC contigs, bridges the centromere, and includes an additional 5 Mb of 5q DNA. The average marker density is 95 kb. This integrated 5p map will serve as a resource for the continuing Localization of genes on the short arm of human chromosome 5 and as a framework for both generating and aligning the DNA sequence of this region. C1 Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Ctr Human Genome Studies, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Software Design & Dev Grp, Los Alamos, NM 87545 USA. Thomas Jefferson Univ, Dept Mol Pharmacol & Biochem, Philadelphia, PA 19107 USA. Univ Calif Irvine, Coll Med, Dept Biol Chem, Irvine, CA 92697 USA. RP Grady, DL (reprint author), Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. NR 53 TC 5 Z9 7 U1 0 U2 1 PU COLD SPRING HARBOR LAB PRESS PI PLAINVIEW PA 1 BUNGTOWN RD, PLAINVIEW, NY 11724 USA SN 1088-9051 J9 GENOME RES JI Genome Res. PD DEC PY 1999 VL 9 IS 12 BP 1250 EP 1267 DI 10.1101/gr.9.12.1250 PG 18 WC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity GA 270RU UT WOS:000084550600012 PM 10613848 ER PT J AU Rojas, K de la Pena, LS Gallardo, T Simmons, A Nyce, K McGrath, R Considine, E Vasko, AJ Peterson, E Grady, D Cox, R Andrew, LJ Lovett, M Overhauser, J Williams, CJ AF Rojas, K de la Pena, LS Gallardo, T Simmons, A Nyce, K McGrath, R Considine, E Vasko, AJ Peterson, E Grady, D Cox, R Andrew, LJ Lovett, M Overhauser, J Williams, CJ TI Physical map and characterization of transcripts in the candidate interval for familial chondrocalcinosis at chromosome 5p15.1 SO GENOMICS LA English DT Article ID PYROPHOSPHATE ARTHROPATHY; ARTICULAR-CARTILAGE; MOLECULAR-CLONING; HUMAN DNA; FRAGMENTS; CDNAS; REGIONS; VECTOR; GENE AB The gene for familial chondrocalcinosis (MIM 118600; gene symbol CCAL2) has been localized to a 0.8-cM interval on the short arm of chromosome 5, between the polymorphic microsatellite markers D5S416 and D5S2114. We have undertaken the physical and transcript mapping of this interval, as well as regions telomeric to the interval, in an attempt to define ultimately the gene for this disorder. The physical map is composed of YAC, BAG, PAC, and cosmid resources and spans a physical distance of approximately 0.3 Mb. Using cDNA selection, we have identified eight novel transcripts in and around the interval; two of the selected transcripts reside in the candidate interval. We have also more precisely placed several expressed sequence tags (ESTs) that were previously mapped by radiation hybrid analysis and were reported to reside in or near the candidate interval. Two of the ESTs analyzed overlap with the selected cDNAs that reside in the candidate interval. All of the selected cDNAs are expressed partial transcripts, as determined by Northern blot analysis, and using RT-PCR analysis, me have determined that the cDNAs that reside in the candidate interval are expressed in cartilage and synovium, tissues that are presumably relevant to the chondrocalcinosis phenotype. (C) 1999 Academic Press. C1 Thomas Jefferson Univ, Dept Biochem & Mol Pharmacol, Philadelphia, PA 19107 USA. Thomas Jefferson Univ, Dept Med, Div Rheumatol, Philadelphia, PA 19107 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Texas, SW Med Ctr, Dallas, TX 75235 USA. Univ Oxford, Wellcome Trust Ctr Human Genet, Oxford, England. RP Williams, CJ (reprint author), Thomas Jefferson Univ, Dept Biochem & Mol Pharmacol, BLSB508,233 S 10th St, Philadelphia, PA 19107 USA. FU NHGRI NIH HHS [R01 HG00368]; NIAMS NIH HHS [R01 AR44360]; Wellcome Trust NR 18 TC 10 Z9 11 U1 0 U2 0 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 DEC 1 PY 1999 VL 62 IS 2 BP 177 EP 183 DI 10.1006/geno.1999.5997 PG 7 WC Biotechnology & Applied Microbiology; Genetics & Heredity SC Biotechnology & Applied Microbiology; Genetics & Heredity GA 275MZ UT WOS:000084825100007 PM 10610710 ER PT J AU Sims, KWW DePaolo, DJ Murrell, MT Baldridge, WS Goldstein, S Clague, D Jull, M AF Sims, KWW DePaolo, DJ Murrell, MT Baldridge, WS Goldstein, S Clague, D Jull, M TI Porosity of the melting zone and variations in the solid mantle upwelling rate beneath Hawaii: Inferences from U-238-Th-230-Ra-226 and U-235-Pa-231 disequilibria SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article; Proceedings Paper CT Conference on The Chemical History of the Earth CY MAY, 1997 CL PARIS, FRANCE SP MaxPlanck Postdoctoral Fellowship ID IONIZATION MASS-SPECTROMETRY; URANIUM SERIES DISEQUILIBRIA; U-238 TH-230 DISEQUILIBRIUM; DIVERSE BASALT TYPES; JUAN-DE-FUCA; DECAY-SERIES; RADIOACTIVE DISEQUILIBRIA; ISOTOPIC SYSTEMATICS; FEMTOGRAM QUANTITIES; PA-231 DISEQUILIBRIA AB Measurements of U-238-Th-230-Ra-226 and U-235-Pa-231 disequilibria in a suite of tholeiitic-to-basanitic lavas provide estimates of porosity, solid mantle upwelling rate and melt transport times beneath Hawaii. The observation that (Th-230/U-238) > 1 indicates that garnet is required as a residual phase in the magma sources for all of the lavas. Both chromatographic porous flow and dynamic melting of a garnet peridotite source can adequately explain the combined U-Th-Ra and U-Pa data for these Hawaiian basalts. For chromatographic porous flow, the calculated maximum porosity in the melting zone ranges from 0.3-3% for tholeiites and 0.1-1% for alkali basalts and basanites, and solid mantle upwelling rates range from 40 to 100 cm yr(-1) for tholeiites and from 1 to 3 cm yr(-1) for basanites. For dynamic melting, the escape or threshold porosity is 0.5-2% for tholeiites and 0.1-0.8% for alkali basalts and basanites, and solid mantle upwelling rates range from 10 to 30 cm yr(-1) for tholeiites and from 0.1 to 1 cm yr(-1) for basanites. Assuming a constant melt productivity, calculated total melt fractions range from 15% for the tholeiitic basalts to 3% for alkali basalts and basanites. Copyright (C) 1999 Elsevier Science Ltd. C1 Univ Calif Berkeley, Dept Geol & Geophys, Berkeley Ctr Isotope Geochem, Berkeley, CA 94720 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Woods Hole Oceanog Inst, Dept Geol & Geophys, Woods Hole, MA 02543 USA. Monterey Bay Aquarium Res Inst, Moss Landing, CA 95039 USA. RP Sims, KWW (reprint author), Univ Calif Berkeley, Dept Geol & Geophys, Berkeley Ctr Isotope Geochem, Berkeley, CA 94720 USA. EM ksims@mail.whoi.edu NR 69 TC 126 Z9 127 U1 1 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 EI 1872-9533 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD DEC PY 1999 VL 63 IS 23-24 BP 4119 EP 4138 DI 10.1016/S0016-7037(99)00313-0 PG 20 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 268CY UT WOS:000084397800017 ER PT J AU Yang, XN Stump, BW Pearson, DC AF Yang, XN Stump, BW Pearson, DC TI Moment tensor inversion of single-hole mining cast blasts SO GEOPHYSICAL JOURNAL INTERNATIONAL LA English DT Article DE explosion seismology; inversion; moment tensor ID QUARRY BLASTS; EXPLOSIONS; SPECTRA; DISCRIMINATION; EARTHQUAKES; DISTANCES AB We carried out a controlled held experiment to characterize the single-hole shots typically used in multishot mining blasts. Eight single-hole mining shots were detonated on an overburden bench, and near-source (49-154 m) ground accelerations were recorded. The sources were characterized by their cylindrical geometry, proximity (6 m) to an 11-m vertical free face and the Earth's free surface, and lack of confinement at the horizontal free surface and the vertical free face. Charge sizes ranged from 59 to 296 kg. The ground motion data, supplemented with standard refraction data, were used to constrain the local velocity model. The resultant Green's functions and the observational data were used to invert for the second-order, time-dependent source moment tensors with a frequency domain method. Despite the large isotropic component (similar to 80 per cent), the source moment tensors show a significant degree of asymmetry among the diagonal components. The first peak of the vertical component M(33) is 39 per cent (+/-15 per cent) larger than the first peaks of the two horizontal components, which have similar amplitudes. This observation cannot be explained by the cylindrical geometry of the source or the presence of the vertical free face in the source region. The complex source time history, an associated spectral peak and the increase of the degree of asymmetry with time among diagonal moment tensor components are indicative of secondary source effects. Together with the source asymmetry, they could be explained by the effects of a vertical spall source that includes both the vertical cast of the burden and, more importantly, the vertical spallation of the strata around the source. The horizontal cast of the burden was not resolved in the inverted source moment tensors, possibly due to their long period and low seismic efficiency. Although the off-diagonal moment tensor components are much smaller than the diagonal components, they contribute significantly to the seismic wave generation. Further studies are required to interpret their generating mechanisms. C1 Los Alamos Natl Lab, Geoanal Grp, Los Alamos, NM 87545 USA. So Methodist Univ, Dept Geol Sci, Dallas, TX 75275 USA. Los Alamos Natl Lab, Geophys Grp, Los Alamos, NM 87545 USA. RP Yang, XN (reprint author), Los Alamos Natl Lab, Geoanal Grp, MS D443, Los Alamos, NM 87545 USA. EM xyang@lanl.gov NR 42 TC 4 Z9 4 U1 0 U2 1 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0956-540X J9 GEOPHYS J INT JI Geophys. J. Int. PD DEC PY 1999 VL 139 IS 3 BP 679 EP 690 DI 10.1046/j.1365-246x.1999.00958.x PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 265BP UT WOS:000084219400007 ER PT J AU Swenson, JL Beck, SL Zandt, G AF Swenson, JL Beck, SL Zandt, G TI Regional distance shear-coupled PL propagation within the northern Altiplano, central Andes SO GEOPHYSICAL JOURNAL INTERNATIONAL LA English DT Article DE body waves; crustal structure; seismic wave propagation; sensitivity; synthetic seismograms ID SEISMOGRAMS; WAVES AB Properties of the shear-coupled P wavetrain (SPL) from regional earthquakes provide important information about the structure of the crust and upper mantle. We investigate broad-band seismic data from intermediate-depth earthquakes and develop a grid search technique using synthetic seismograms to study the sensitivity of SPL and to model the crustal structure of the northern Altiplano, central Andes. Waveforms from an earthquake that occurred on 1994 December 12 within the Nazca slab beneath the Altiplano display a clear SPL wavetrain at the temporary stations deployed during the BANJO and SEDA experiments. We relocate this event and determine the moment tensor by inverting the complete long-period waveforms. With these source parameters fixed, we perform sensitivity analyses using a reflectivity technique to compute synthetic seismograms at a distance of 313 km (BANJO station 2, SALI). We find that, at this distance, the long-period SPL wavetrain is sensitive to the following model parameters, in order of decreasing sensitivity: crustal V-P/V-S, mantle V-P/V-S, average crustal velocity, crustal thickness, focal depth, distance (location), crustal Q(alpha) and Q(beta), and mantle velocity. We develop a grid search method to investigate the four parameters of the crust/upper mantle model to which the synthetic seismograms are most sensitive at SALI (crustal V-P/V-S, mantle V-P/V-S, average crustal velocity, crustal thickness). Trade-offs exist among all four of the model parameters, resulting in a range of acceptable crustal models that provide excellent fits between the data and synthetic seismograms in the passband of 15-100 s at a single station. However, by using data at a range of distances (150-450 km) we find that the model that provides the best overall fit between the data and synthetic seismograms, and thus best approximates the average characteristics of the crust and upper mantle structure of the northern Altiplano, is characterized by an average crustal velocity of 6.0 km s(-1), a crustal Poisson's ratio (sigma(crust)) of 0.25 and a mantle Poisson's ratio (sigma(mantle)) of 0.27. The resulting models confirm previous estimates of low Poisson's ratios, low average crustal velocity and thick crust in the Altiplano. C1 Univ Arizona, Dept Geosci, So Arizona Seism Observ, Tucson, AZ 85721 USA. RP Swenson, JL (reprint author), Univ Calif Lawrence Livermore Natl Lab, Geophys & Global Secur Div, POB 808,L-206, Livermore, CA 94550 USA. NR 18 TC 6 Z9 6 U1 0 U2 2 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 DEC PY 1999 VL 139 IS 3 BP 743 EP 753 DI 10.1046/j.1365-246x.1999.00968.x PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 265BP UT WOS:000084219400011 ER PT J AU Durham, WB Kirby, SH Stern, LA AF Durham, WB Kirby, SH Stern, LA TI Steady-state flow of solid CO2: Preliminary results SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID METHANE AB To help answer the question of how much solid CO2 exists in the Martian south polar cap, we performed a series of laboratory: triaxial deformation experiments at constant displacement rate in compression on jacketed cylinders of pure, polycrystalline CO2. Test conditions were temperatures 150 < T< 190 K, hydrostatic confining pressures 5 less than or equal to P less than or equal to 40 MPa, and strain rates 4.5 x 10(-8) less than or equal to (epsilon) over dot less than or equal to 4.3 x 10(-4) s(-1). Most of the measurements follow a constitutive law of the form epsilon =A sigma(n)exp(-Q/RT), where sigma is the applied differential stress, R is the gas constant, and the other constants have values as follows: A = 10(3.86) MPa(-n)s(-1) n = 5.6, and Q = 33 kJ/mol. Solid CO2 is markedly weaker than water ice. Our results suggest that the:south polar cap on Mars is unlikely to be predominately solid CO2, because the elevation and estimated age of the cap is difficult to reconcile with the very weak rheology of the material. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. US Geol Survey, Menlo Park, CA 94025 USA. RP Durham, WB (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 12 TC 18 Z9 18 U1 0 U2 1 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 DEC 1 PY 1999 VL 26 IS 23 BP 3493 EP 3496 DI 10.1029/1999GL008373 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 261LN UT WOS:000084010800018 ER PT J AU Sedivy, RA Shafer, JM Bilbrey, LC AF Sedivy, RA Shafer, JM Bilbrey, LC TI Design screening tools for passive funnel and gate systems SO GROUND WATER MONITORING AND REMEDIATION LA English DT Article AB The funnel and gate remediation concept (Starr and Cherry 1993) represents a promising, yet relatively under-developed, technology for the passive control and in situ remediation of contaminated ground water. Effective design and implementation of such a system may, however. prove difficult under conditions of large or unpredictable variations in contaminant migration or ground water flow Numerical modeling of two-dimensional ground water flow has been used to predict the hydraulic performance of passive, straight, or winged funnel and gate configurations over a range of hydrogeologic and ambient ent ground water flow conditions. The results of these analyses were used to construct generic correlation diagrams relating upstream capture zone or gate throughput to the barrier, gate, and aquifer characteristics. These diagrams serve as useful screening tools to (1) quantitatively estimate the capture zone of predetermined funnel and gate configurations, or (2) develop preliminary funnel and gate designs that will yield a desired capture zone, independent of aquifer characteristics. C1 Argonne Natl Lab, Div Environm Res, Appl Geosci & Environm Management Sect, Argonne, IL 60439 USA. RP Sedivy, RA (reprint author), Argonne Natl Lab, Div Environm Res, Appl Geosci & Environm Management Sect, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 16 TC 15 Z9 15 U1 0 U2 1 PU GROUND WATER PUBLISHING CO PI WESTERVILLE PA 601 DEMPSEY RD, WESTERVILLE, OH 43081 USA SN 1069-3629 J9 GROUND WATER MONIT R JI Ground Water Monit. Remediat. PD WIN PY 1999 VL 19 IS 1 BP 125 EP 133 DI 10.1111/j.1745-6592.1999.tb00195.x PG 9 WC Water Resources SC Water Resources GA 170NG UT WOS:000078811700010 ER PT J AU Landa, ER Beals, DR Halverson, JE Michel, RL Cefus, GR AF Landa, ER Beals, DR Halverson, JE Michel, RL Cefus, GR TI Tritium and plutonium in waters from the Bering and Chukchi Seas SO HEALTH PHYSICS LA English DT Article DE tritium; Pu-239; Pu-240; radioactivity, environmental ID ARCTIC-OCEAN; FALLOUT PLUTONIUM; NORTH PACIFIC; DEEP-SEA; DISTRIBUTIONS; TRANSPORT; ISOTOPES; ATLANTIC AB During the summer of 1993, seawater in the Bering and (Chukchi Seas was sampled on a joint Russian-American cruise [BERPAC] of the RV Okean to determine concentrations of tritium, Pu-239 and Pu-240. Concentrations of tritium were determined by electrolytic enrichment and liquid scintillation counting. Tritium levels ranged up to 420 mBq L-1 and showed no evidence of inputs other than those attributed to atmospheric nuclear weapons testing. Plutonium was recovered from water samples hy ferric hydroxide precipitation, and concentrations were determined by thermal ionization mass spectrometry. Pu239+240 concentrations ranged from <1 to 5.5 mu Bq L-1. These concentrations are lower than those measured in water samples from other parts of the ocean during the mid-1960's to the late 1980's. The Pu-240:Pu-239 ratios, although associated with large uncertainties, suggest that most of the plutonium is derived from world-wide fallout, As points of comparison, the highest concentrations of tritium and plutonium observed here were about five orders of magnitude lower than the maximum permissible concentrations allowed in water released to the off-site environs from licensed nuclear facilities in the United States. This study and others sponsored by the international Atomic Energy Agency and the Office of Naval Research's Arctic Nuclear Waste Assessment Program are providing data for the assessment of potential radiological impacts in the Arctic regions associated with nuclear waste disposal by the former Soviet Union. C1 US Geol Survey, Reston, VA 20192 USA. Westinghouse Savannah River Co, Savannah River Technol Ctr, Measurement Technol Dept, Aiken, SC 29808 USA. US Geol Survey, Menlo Park, CA 94025 USA. EM erlanda@usgs.gov NR 34 TC 1 Z9 1 U1 1 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 DEC PY 1999 VL 77 IS 6 BP 668 EP 676 DI 10.1097/00004032-199912000-00011 PG 9 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 255HD UT WOS:000083662700010 PM 10568546 ER PT J AU Carlton, WH Murphy, CE Jannik, GT Simpkins, AA AF Carlton, WH Murphy, CE Jannik, GT Simpkins, AA TI Radiostrontium in the Savannah River Site environment SO HEALTH PHYSICS LA English DT Article DE water; strontium; contamination, environmental; dose AB The Savannah River Site has produced plutonium, tritium, and other special nuclear materials for national defense, other government programs, and some civilian purposes. Strontium has been released to the environment during the operation of five reactors, two radiochemical processing facilities, and other supporting facilities. During the period 1954-1996, 110 GBq of Sr-90 were released to the atmosphere and 5,400 GBq were released to site streams. The maximum individual effective dose equivalent at the site boundary was estimated to be 72 mu Sv from atmospheric releases and 25 mu Sv from liquid releases. The 80-km population dose was 0.3 person-Sv. C1 Westinghouse Savannah River Co, Savannah River Technol Ctr, Aiken, SC 29808 USA. EM gerald.jannick@srs.gov NR 21 TC 1 Z9 1 U1 1 U2 1 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 DEC PY 1999 VL 77 IS 6 BP 677 EP 685 DI 10.1097/00004032-199912000-00012 PG 9 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 255HD UT WOS:000083662700011 PM 10568547 ER PT J AU Ma, WX Liu, LC Kisslinger, LS Shen, PN AF Ma, WX Liu, LC Kisslinger, LS Shen, PN TI Gluonic content of the Pomeron SO HIGH ENERGY PHYSICS AND NUCLEAR PHYSICS-CHINESE EDITION LA English DT Letter DE Pomeron; gluon; glueball ID J/PSI RADIATIVE DECAYS; ELASTIC-SCATTERING AB It is shown that the Pomeron could be regarded as a Reggeized Tensor Glueball with a trajectory of alpha(P)(t) = 1.08 + 0.2GeV(-2)t. Under this theory, the total cross section measured for pp elastic scattering at high energies is reproduced successfully. The best fits to experimental data lead to a Gamma(xi-->p (p) over bar) = 9 +/- 3MeV and Gamma(xi) > 50MeV, and J = 4 for spin of the tensor glueball m(xi)(2230) is precluded. C1 Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China. Chinese Acad Sci, Inst Modern Phys, Lanzhou 730000, Peoples R China. Chinese Acad Sci, Inst Theoret Phys, Beijing 100080, Peoples R China. CCAST, World Lab, Ctr Theoret Phys, Beijing 100080, Peoples R China. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15213 USA. RP Ma, WX (reprint author), Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China. NR 13 TC 0 Z9 0 U1 0 U2 1 PU SCIENCE PRESS PI BEIJING PA 16 DONGHUANGCHENGGEN NORTH ST, BEIJING 100717, PEOPLES R CHINA SN 0254-3052 J9 HIGH ENERG PHYS NUC JI High Energy Phys. Nucl. Phys.-Chin. Ed. PD DEC PY 1999 VL 23 IS 12 BP 1253 EP 1256 PG 4 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 271VK UT WOS:000084614500020 ER PT J AU Ma, WX Liu, LC Liu, B Shen, PN Jiang, HQ AF Ma, WX Liu, LC Liu, B Shen, PN Jiang, HQ TI A new relativistic and singularity free form factor of baryon vertex SO HIGH ENERGY PHYSICS AND NUCLEAR PHYSICS-CHINESE EDITION LA English DT Letter DE formfactor; baryon; coupling vertex AB A new relativistic and singularity free form factor for baryon vertex is suggested. The form factor satisfies the crossing symmetry of scattering amplitude transfered from t-channel to s-channel for strong interaction processes. C1 Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China. Chinese Acad Sci, Inst Modern Phys, Lanzhou 730000, Peoples R China. Chinese Acad Sci, Inst Theoret Phys, Beijing 100080, Peoples R China. CCAST, World Lab, Ctr Theoret Phys, Beijing 100080, Peoples R China. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Ma, WX (reprint author), Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China. NR 4 TC 0 Z9 0 U1 0 U2 0 PU SCIENCE PRESS PI BEIJING PA 16 DONGHUANGCHENGGEN NORTH ST, BEIJING 100717, PEOPLES R CHINA SN 0254-3052 J9 HIGH ENERG PHYS NUC JI High Energy Phys. Nucl. Phys.-Chin. Ed. PD DEC PY 1999 VL 23 IS 12 BP 1257 EP 1259 PG 3 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 271VK UT WOS:000084614500021 ER PT J AU Kim, WH AF Kim, WH TI Adaptive lossless coding scheme of lattice vector quantisation SO IEE PROCEEDINGS-VISION IMAGE AND SIGNAL PROCESSING LA English DT Article ID QUANTIZATION AB In the process of quantisation, a lattice vector quantiser (LVQ) generates radius and index sequences. In lossless coding, the radius sequence is run-length coded and then Huffman or arithmetic coded, and the index sequence is represented by fixed binary bits. The author has improved the LVQ lossless coding by removing the redundant information between radius sequence and index sequence. An algorithm is developed that redistributes radius and index sequences. The algorithm adaptively shifts down large indices to smaller values and reduces the index bits. Hence, the proposed LVQ lossless coding method reduces the gap between actual coding bit rates and the optimal bit rate boundary For a Laplacian source the proposed lossless coding scheme achieves more than 10% of bit reduction at bit rates higher than 0.7 bits/sample over the traditional lossless coding method. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Myongji Univ, Informat & Commun Dis, San 38, Yongin, Kyoungki Do, South Korea. NR 9 TC 2 Z9 2 U1 0 U2 0 PU INST ENGINEERING TECHNOLOGY-IET PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 1350-245X J9 IEE P-VIS IMAGE SIGN JI IEE Proc.-Vis. Image Signal Process. PD DEC PY 1999 VL 146 IS 6 BP 317 EP 325 DI 10.1049/ip-vis:19990723 PG 9 WC Engineering, Electrical & Electronic SC Engineering GA 294FY UT WOS:000085901900005 ER PT J AU Kim, WH AF Kim, WH TI Estimating the distortion and entropy-coded bit rate of lattice vector quantiser for a Laplacian source SO IEE PROCEEDINGS-VISION IMAGE AND SIGNAL PROCESSING LA English DT Article ID QUANTIZATION AB For practical use of lattice vector quantisers (LVQs), the codebook sizes are pre-decided and the lattice is scaled to control quantisation distortion and bit rate. Formulas are derived estimating both the distortion and the bit rate as functions of a scaling factor of a LVQ, while a lossless coding method is specified as the rotational coordinate method and input sources are assumed to be Laplacian sources. Unlike conventional approaches based on asymptotical assumptions, the codebook size is limited first, and then the vector space is partitioned according to the characteristic of the source distribution. The proposed estimates are more realistic for practical applications because they handle practical codebook sizes. The lattice points are also counted at each surface on which lattice points exist. The Monte Carlo simulation verifies that the proposed estimates are accurate enough for determining the optimal scaling factor. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Myongji Univ, Informat & Commun Div, San 38, Nam Dong Yong In, Kyoungki Do, South Korea. NR 18 TC 0 Z9 0 U1 0 U2 1 PU INST ENGINEERING TECHNOLOGY-IET PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 1350-245X J9 IEE P-VIS IMAGE SIGN JI IEE Proc.-Vis. Image Signal Process. PD DEC PY 1999 VL 146 IS 6 BP 326 EP 333 DI 10.1049/ip-vis:19990706 PG 8 WC Engineering, Electrical & Electronic SC Engineering GA 294FY UT WOS:000085901900006 ER PT J AU Pu, R Wilmsen, CW Geib, KM Choquette, KD AF Pu, R Wilmsen, CW Geib, KM Choquette, KD TI Thermal resistance of VCSEL's bonded to integrated circuits SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Article DE thermal resistance; vertical cavity surface emitting lasers; semiconductor lasers ID ARRAYS AB The thermal resistance of vertical-cavity surface-emitting lasers (VCSEL's) hip chip bonded to GaAs substrates and CMOS integrated circuits has been measured. The measurements on GaAs show that if the bonding is done properly, the bonding does not add significantly to the thermal resistance. However, the SiO2 under the CMOS bonding pad can double the thermal resistance unless measures are taken to improve the thermal conductance of these layers, Finite element simulations indicate that the thermal resistance of bonded VCSEL's increases rapidly as the solder bond size and the aperture size decrease below similar to 10 mu m. C1 Colorado State Univ, Dept Elect & Comp Engn, Ft Collins, CO 80523 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Pu, R (reprint author), Colorado State Univ, Dept Elect & Comp Engn, Ft Collins, CO 80523 USA. NR 13 TC 27 Z9 30 U1 1 U2 1 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 DEC PY 1999 VL 11 IS 12 BP 1554 EP 1556 DI 10.1109/68.806844 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 263AL UT WOS:000084100400010 ER PT J AU Sathaye, J Sinton, J Heller, T AF Sathaye, J Sinton, J Heller, T TI Doing better with less energy SO IEEE SPECTRUM LA English DT Article C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Int Energy Studies Grp, Berkeley, CA 94720 USA. Stanford Univ, Sch Law, Stanford, CA 94305 USA. RP Sathaye, J (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Int Energy Studies Grp, Berkeley, CA 94720 USA. NR 12 TC 2 Z9 2 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 0018-9235 J9 IEEE SPECTRUM JI IEEE Spectr. PD DEC PY 1999 VL 36 IS 12 BP 42 EP 49 DI 10.1109/6.809123 PG 8 WC Engineering, Electrical & Electronic SC Engineering GA 261WV UT WOS:000084034200014 ER PT J AU Logan, J AF Logan, J TI Balancing the books on energy pricing SO IEEE SPECTRUM LA English DT Article C1 Battelle Pacific NW Natl Lab, Richland, WA 99352 USA. RP Logan, J (reprint author), Battelle Pacific NW Natl Lab, Richland, WA 99352 USA. NR 0 TC 0 Z9 0 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 0018-9235 J9 IEEE SPECTRUM JI IEEE Spectr. PD DEC PY 1999 VL 36 IS 12 BP 59 EP 61 DI 10.1109/6.809126 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA 261WV UT WOS:000084034200017 ER PT J AU Bretz, EA Singh, V AF Bretz, EA Singh, V TI India restructures tariffs and oversight SO IEEE SPECTRUM LA English DT Article C1 Pacific NW Natl Lab, Adv Int Studies Unit, Washington, DC USA. RP Bretz, EA (reprint author), Pacific NW Natl Lab, Adv Int Studies Unit, Washington, DC USA. NR 9 TC 0 Z9 0 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 0018-9235 J9 IEEE SPECTRUM JI IEEE Spectr. PD DEC PY 1999 VL 36 IS 12 BP 61 EP 63 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA 261WV UT WOS:000084034200018 ER PT J AU Sheth, A Lasrado, V White, M Paranthaman, M AF Sheth, A Lasrado, V White, M Paranthaman, M TI Bench scale evaluation of batch mode dip-coating of sol-gel LaAlO3 buffer material (vol 9, pg 1514, 1999) SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Correction C1 Univ Tennessee, Inst Space, Tullahoma, TN 37388 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Sheth, A (reprint author), Univ Tennessee, Inst Space, Tullahoma, TN 37388 USA. RI Paranthaman, Mariappan/N-3866-2015 OI Paranthaman, Mariappan/0000-0003-3009-8531 NR 1 TC 0 Z9 0 U1 1 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD DEC PY 1999 VL 9 IS 4 BP 4733 EP 4733 DI 10.1109/TASC.1999.819345 PG 1 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 284BM UT WOS:000085310900015 ER PT J AU De Broe, AM Drouilhet, S Gevorgian, V AF De Broe, AM Drouilhet, S Gevorgian, V TI A peak power tracker for small wind turbines in battery charging applications SO IEEE TRANSACTIONS ON ENERGY CONVERSION LA English DT Article DE wind turbine; battery charging; DC/DC converter ID SPEED AB This paper describes the design, implementation and testing of a prototype version of a peak power tracking system for small wind turbines in battery charging applications. The causes for the poor performance of small wind turbines in battery charging applications are explained and previously proposed configurations to increase the power output of the wind turbines are discussed. Through computer modeling of the steady-state operation the potential performance gain of the proposed system in comparison with existing systems is calculated. It is shown that one configuration consisting of reactive compensation by capacitors and a DC/DC converter is able to optimally load the wind turbine and thus obtain maximum energy capture over the whole range of wind speeds. A proof of concept of the peak power tracking system is provided by building and testing a prototype version The peak power tracking system is tested in combination with a typical small wind turbine generator on a dynamometer. Steady-state operating curves confirming the performance improvement predicted by calculations are presented. C1 Natl Wind Technol Ctr, Natl Renewable Energy Lab, Golden, CO USA. RP De Broe, AM (reprint author), Netherlands Energy Res Fdn, Petten, Netherlands. NR 7 TC 97 Z9 98 U1 0 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0885-8969 J9 IEEE T ENERGY CONVER JI IEEE Trans. Energy Convers. PD DEC PY 1999 VL 14 IS 4 BP 1630 EP 1635 DI 10.1109/60.815116 PG 6 WC Energy & Fuels; Engineering, Electrical & Electronic SC Energy & Fuels; Engineering GA 271HV UT WOS:000084588900139 ER PT J AU Wohlberg, B de Jager, G AF Wohlberg, B de Jager, G TI A review of the fractal image coding literature SO IEEE TRANSACTIONS ON IMAGE PROCESSING LA English DT Review DE fractals; image coding ID ITERATED FUNCTION SYSTEMS; WAVELET-BASED THEORY; DELAUNAY TRIANGULATION; VECTOR QUANTIZATION; DECODING ALGORITHM; COMPRESSION; PERFORMANCE; TRANSFORMS; SUBTREES; SEARCH AB Fractal image compression is a relatively recent technique based on the representation of an image by a contractive transform, on the space of images, for which the fixed point Is close to the original image. This broad principle encompasses a very wide variety of coding schemes, many of which have been explored in the rapidly growing body of published research. While certain theoretical aspects of this representation are well established, relatively little attention has been given to the construction of a coherent underlying image model that would justify its use. Most purely fractal-based schemes are not competitive with the current state of the art, but hybrid schemes incorporating fractal compression and alternative techniques have achieved considerably greater success. This review represents a survey of the most significant advances, both practical and theoretical, since the publication in 1990 of Jacquin's original fractal coding scheme. C1 Univ Cape Town, Dept Elect Engn, Digital Imaging Proc Lab, ZA-7701 Rondebosch, South Africa. RP Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. EM brendt@cnls.lanl.gov RI Wohlberg, Brendt/M-7764-2015 OI Wohlberg, Brendt/0000-0002-4767-1843 NR 139 TC 159 Z9 191 U1 2 U2 21 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1057-7149 EI 1941-0042 J9 IEEE T IMAGE PROCESS JI IEEE Trans. Image Process. PD DEC PY 1999 VL 8 IS 12 BP 1716 EP 1729 DI 10.1109/83.806618 PG 14 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 261VP UT WOS:000084031200006 PM 18267449 ER PT J AU Tantawi, SG Loewen, RJ Nantista, CD Vlieks, AE AF Tantawi, SG Loewen, RJ Nantista, CD Vlieks, AE TI The generation of 400-MW RF pulses at X-band using resonant delay lines SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article; Proceedings Paper CT 1999 IEEE MTT-S International Microwave Symposium CY JUN 13-19, 1999 CL ANAHEIM, CALIFORNIA SP IEEE, Microwave Theory & Techniques Soc AB In this paper, we present theory and experimental data for a resonant-delay-line pulse-compression system. The system is fed by two high-power klystrons at X-band. The peak output power is four times the input power. The system produces pat-top output pulses. It uses evacuated room-temperature copper delay lines as a means of storing energy. These lines achieved a quality factor greater than 4.3 x 10(5), with total losses due to external components measured at 4%, We compare theory with experimental results. The system produced 150-ns pulses at power levels around 470 MW. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Cairo Univ, Commun & Elect Dept, Giza, Egypt. RP Tantawi, SG (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 9 TC 15 Z9 15 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 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD DEC PY 1999 VL 47 IS 12 BP 2539 EP 2546 DI 10.1109/22.809004 PG 8 WC Engineering, Electrical & Electronic SC Engineering GA 264VZ UT WOS:000084204800049 ER PT J AU Chadwick, MB Normand, E AF Chadwick, MB Normand, E TI Use of new ENDF/B-VI proton and neutron cross sections for single event upset calculations SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1999 IEEE Nuclear and Space Radiation Effects Conference (NSREC 99) CY JUL 12-16, 1999 CL NORFOLK, VIRGINIA SP IEEE Nuclear & Plasma Sci Soc, Raduat Effects Comm, Def Threat Redyct Agcy, Sandia Natl Lab, NASA Goddard Space Flight Ctr, Jet Propuls Lab, Air Force Res Lab ID INDUCED SEU; MEMORIES; RATES AB Single-event upsets (SEU) in microelectronics are calculated from newly-developed silicon nuclear reaction recoil data for incident protons and neutrons with energies up to 150 MeV. This paper focusses on the nuclear reaction physics that is important for calculating recoil spectra, and burst generation rate spectra. Comparisons are made with previous results, obtained from intranuclear cascade calculations as well as from previous ENDF data below 20 MeV, to demonstrate new features in the present calculations. Calculated SEU cross sections are compared with measured data. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Boeing Mil Aircraft & Missle Syst, Seattle, WA 98124 USA. RP Chadwick, MB (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 23 TC 31 Z9 32 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1999 VL 46 IS 6 BP 1386 EP 1394 DI 10.1109/23.819097 PN 1 PG 9 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 279RG UT WOS:000085058500011 ER PT J AU Winokur, PS Lum, GK Shaneyfelt, MR Sexton, FW Hash, GL Scott, L AF Winokur, PS Lum, GK Shaneyfelt, MR Sexton, FW Hash, GL Scott, L TI Use of COTS microelectronics in radiation environments SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1999 IEEE Nuclear and Space Radiation Effects Conference (NSREC 99) CY JUL 12-16, 1999 CL NORFOLK, VIRGINIA SP IEEE Nuclear & Plasma Sci Soc, Raduat Effects Comm, Def Threat Redyct Agcy, Sandia Natl Lab, NASA Goddard Space Flight Ctr, Jet Propuls Lab, Air Force Res Lab ID HARDNESS ASSURANCE; CIRCUITS; SEU; TECHNOLOGIES; DEVICE; ION AB This paper addresses key issues for the cost-effective use of COTS (Commercially available Off The Shelf) microelectronics in radiation environments that enable circuit or system designers to manage risks and ensure mission success. We review several factors and tradeoffs affecting the successful application of COTS parts including (1) hardness assurance and qualification issues, (2) system hardening techniques, and (3) life-cycle costs. The paper also describes several experimental studies that address trends in total-dose, transient, and single-event radiation hardness as COTS technology scales to smaller feature sizes. As an example, the level at which dose-rate upset occurs in Samsung SRAMs increases from 1.4x10(8) rad(Si)/s for a 256K SRAM to 7.7x10(9) rad(Si)/s for a 4M SRAM, indicating unintentional hardening improvements in the design or process of a commercial technology. Additional experiments were performed to quantify variations in radiation hardness for COTS parts. In one study, only small (10-15%) variations were found in the dose-rate upset and latchup thresholds for Samsung 4M SRAMs from three different date codes. In another study, irradiations of 4M SRAMs from Samsung, Hitachi, and Toshiba indicate large differences in total-dose radiation hardness. The paper attempts to carefully define terms and clear up misunderstandings about the definitions of "COTS" and "radiation-hardened (RH)" technology. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Lockheed Martin Missles & Space, Sunnyvale, CA 94088 USA. RP Winokur, PS (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 43 TC 19 Z9 20 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 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1999 VL 46 IS 6 BP 1494 EP 1503 DI 10.1109/23.819113 PN 1 PG 10 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 279RG UT WOS:000085058500027 ER PT J AU Fleetwood, DM Winokur, PS Riewe, LC Flament, O Paillet, P Leray, JL AF Fleetwood, DM Winokur, PS Riewe, LC Flament, O Paillet, P Leray, JL TI The role of electron transport and trapping in MOS total-dose modeling SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1999 IEEE Nuclear and Space Radiation Effects Conference (NSREC 99) CY JUL 12-16, 1999 CL NORFOLK, VIRGINIA SP IEEE Nuclear & Plasma Sci Soc, Raduat Effects Comm, Def Threat Redyct Agcy, Sandia Natl Lab, NASA Goddard Space Flight Ctr, Jet Propuls Lab, Air Force Res Lab ID OXIDE-SEMICONDUCTOR DEVICES; BORDER TRAPS; INTERFACE STATES; SILICON DIOXIDE; AMORPHOUS SIO2; RADIATION; CHARGE; DEPENDENCE; FIELD; SIMULATION AB Radiation-induced hole and electron transport and trapping are fundamental to MOS total-dose models. Here we separate the effects of electron-hole annihilation and electron trapping on the neutralization of radiation-induced charge during switched-bias irradiation for hard and soft oxides, via combined thermally stimulated current (TSC) and capacitance-voltage measurements. We also show that present total-dose models cannot account for the thermal stability of trapped electrons near the Si/SiO2 interface, or the inability of electrons in deep or shallow traps to contribute to TSC at positive bias following (1) room-temperature, (2) elevated temperature, or (3) switched..bias irradiation. These results require modifications to modeling parameters and boundary conditions for hole and electron transport in SiO2. Possible types of deep and shallow electron traps in the near-interfacial SiO2 are discussed. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. CEA DAM, F-91680 Bruyeres Le Chatel, France. RP Fleetwood, DM (reprint author), Vanderbilt Univ, Dept Elect Engn, Stn B,POB 92, Nashville, TN 37235 USA. NR 50 TC 15 Z9 16 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1999 VL 46 IS 6 BP 1519 EP 1525 DI 10.1109/23.819116 PN 1 PG 7 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 279RG UT WOS:000085058500030 ER PT J AU Flament, O Paillet, P Leray, JL Fleetwood, DM AF Flament, O Paillet, P Leray, JL Fleetwood, DM TI Considerations on isochronal anneal technique: from measurement to physics SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1999 IEEE Nuclear and Space Radiation Effects Conference (NSREC 99) CY JUL 12-16, 1999 CL NORFOLK, VIRGINIA SP IEEE Nuclear & Plasma Sci Soc, Raduat Effects Comm, Def Threat Redyct Agcy, Sandia Natl Lab, NASA Goddard Space Flight Ctr, Jet Propuls Lab, Air Force Res Lab ID BORDER TRAPS; INTERFACE TRAPS; DEVICES AB The isochronal anneal technique used to predict isothermal anneal behavior of MOS devices is analyzed as a function of experimental parameters (bias during irradiation and anneal). This methodology is applied to different oxide types (hardened and unhardened) with different thickness. Net oxide trapped charge is estimated through I-V or C-V measurements, and electron and hole contributions are determined using the TSC technique. The effects of detrapping of trapped holes and compensating electrons are discussed. The prediction of long term post irradiation response can be accurately done when anneals are performed under positive bias. This prediction is more complex for other bias conditions. The difficulty is related to competitive effects of trapped hole annealing and buildup of compensating electrons as a function of temperature. To enable a precise modeling of long term annealing, a complete model must include, among other things, compensation of holes through tunneling, and/or thermally injected electrons. C1 CEA, DAM, F-91680 Bruyeres Le Chatel, France. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Flament, O (reprint author), CEA, DAM, BP 12, F-91680 Bruyeres Le Chatel, France. NR 19 TC 8 Z9 8 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 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1999 VL 46 IS 6 BP 1526 EP 1533 DI 10.1109/23.819117 PN 1 PG 8 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 279RG UT WOS:000085058500031 ER PT J AU Vanheusden, K Korambath, PP Kurtz, HA Karna, SP Fleetwood, DM Shedd, WM Pugh, RD AF Vanheusden, K Korambath, PP Kurtz, HA Karna, SP Fleetwood, DM Shedd, WM Pugh, RD TI The effect of near-interface network strain on proton trapping in SiO2 SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1999 IEEE Nuclear and Space Radiation Effects Conference (NSREC 99) CY JUL 12-16, 1999 CL NORFOLK, VIRGINIA SP IEEE Nuclear & Plasma Sci Soc, Raduat Effects Comm, Def Threat Redyct Agcy, Sandia Natl Lab, NASA Goddard Space Flight Ctr, Jet Propuls Lab, Air Force Res Lab ID ANNEALED SI/SIO2/SI STRUCTURES; MOBILE PROTONS; THIN-FILMS; GENERATION AB The buildup of positive charge during annealing in forming gas at 600 degrees C was compared for various types of Si/SiO2 interfaces. Our data suggest a correlation between the presence of stressed bonds in the SiO2 network near the Si/SiO2 interface, and the ratio of fixed vs, mobile positive charge (protons) detected near the interface after performing a forming-gas-annealing. We further propose that the presence-of these stressed bonds near the interface is correlated with the oxygen deficiency at the interface and with the confinement of the oxide due to the presence of a Si cover layer. A model based on first-principles quantum mechanical calculations shows a significant decrease in the overall proton binding energy with increasing network strain near the interface. These calculations support our model of mobile proton generation at Si/SiO2 interfaces with large densities of stressed bonds. C1 USAF, Res Lab, Kirtland AFB, NM 87117 USA. Univ Memphis, Dept Chem, Memphis, TN 38152 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Vanheusden, K (reprint author), USAF, Res Lab, 3550 Aberdeen Ave SE, Kirtland AFB, NM 87117 USA. NR 14 TC 16 Z9 16 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 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1999 VL 46 IS 6 BP 1562 EP 1567 DI 10.1109/23.819121 PN 1 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 279RG UT WOS:000085058500035 ER PT J AU Rosenfeld, AB Kaplan, GI Kron, T Allen, BJ Dilmanian, A Orion, I Ren, B Lerch, MLF Holmes-Siedle, A AF Rosenfeld, AB Kaplan, GI Kron, T Allen, BJ Dilmanian, A Orion, I Ren, B Lerch, MLF Holmes-Siedle, A TI MOSFET dosimetry of an X-ray microbeam. SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1999 IEEE Nuclear and Space Radiation Effects Conference (NSREC 99) CY JUL 12-16, 1999 CL NORFOLK, VIRGINIA SP IEEE Nuclear & Plasma Sci Soc, Raduat Effects Comm, Def Threat Redyct Agcy, Sandia Natl Lab, NASA Goddard Space Flight Ctr, Jet Propuls Lab, Air Force Res Lab ID RADIOCHROMIC FILM; RADIATION DOSIMETER; GAMMA; DEVICES; THERAPY; BEAMS AB A metal-oxide-semiconductor field effect transistor (MOSFET) has been used as a radiation monitor to map the profile of a variety of X-ray radiation microbeams. The present work studies the role of the topology of the MOSFET gate oxide when mapping radiation microbeams. The "edge-on" MOSFET has been introduced for microbeam mapping and the spatial resolution of the "edge-on" MOSFET is investigated. Comparison is made with other mapping techniques including, Gafchromic(TM) film, radiographic film, ionization chamber. The results clearly demonstrate the superiority of the "edge-on" MOSFET when applied to mapping of narrow radiation beams. The spatial resolution of the "edge-on" MOSFET is estimated to be 1 mu m and appears to be limited by the width of the gate oxide thickness. C1 Univ Wollongong, Radiat Phys Grp, Wollongong, NSW 2522, Australia. Univ Newcastle, Dept Phys, Newcastle, NSW 2310, Australia. Brookhaven Natl Lab, Upton, NY 11973 USA. RFM Oxford Ltd, Oxford OX8 1PD, England. RP Rosenfeld, AB (reprint author), Univ Wollongong, Radiat Phys Grp, Wollongong, NSW 2522, Australia. RI ORION, ITZHAK/F-2034-2012; Lerch, Michael/C-3303-2014; Rosenfeld, Anatoly/D-1989-2014 NR 22 TC 28 Z9 28 U1 1 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1999 VL 46 IS 6 BP 1774 EP 1780 DI 10.1109/23.819153 PN 1 PG 7 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 279RG UT WOS:000085058500067 ER PT J AU Schwank, JR Shaneyfelt, MR Draper, BL Dodd, PE AF Schwank, JR Shaneyfelt, MR Draper, BL Dodd, PE TI BUSFET - A radiation-hardened SOI transistor SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1999 IEEE Nuclear and Space Radiation Effects Conference (NSREC 99) CY JUL 12-16, 1999 CL NORFOLK, VIRGINIA SP IEEE Nuclear & Plasma Sci Soc, Raduat Effects Comm, Def Threat Redyct Agcy, Sandia Natl Lab, NASA Goddard Space Flight Ctr, Jet Propuls Lab, Air Force Res Lab ID SIMOX BURIED OXIDES; MOS DEVICES AB The total-dose hardness of SOI technology is limited by radiation-induced charge trapping in gate, field, and SOI buried oxides. Charge trapping in the buried oxide can lead to back-channel leakage and makes hardening SOI transistors more challenging than hardening bulk-silicon transistors. Two avenues for hardening the back-channel are 1) to use specially prepared SOI buried oxides that reduce the net amount of trapped positive charge or 2) to design transistors that are less sensitive to the effects of trapped charge in the buried oxide. In this work, we propose a partially-depleted SOI transistor structure for mitigating the effects of trapped charge in the buried oxide on radiation hardness. We call this structure the BUSFET - Body Under Source FET. The BUSFET utilizes a shallow source and a deep drain. As a result, the silicon depletion region at the back channel caused by radiation-induced charge trapping in the buried oxide does not form a conducting path between source and drain. Thus, the BUSFET structure design can significantly reduce radiation-induced back-channel leakage without using specially prepared buried oxides. Total dose hardness is achieved without degrading the intrinsic SEU or dose rate hardness of SOI technology. The effectiveness of the BUSFET structure for reducing total-dose back-channel leakage depends on several variables, including the top silicon film thickness and doping concentration, and the depth of the source. 3-D simulations show that for a body doping concentration of 10(18) cm(-3) a drain bias of 3 V, and a source depth of 90 nm, a silicon film thickness of 180 nm is sufficient to almost completely eliminate radiation-induced back-channel leakage. However, for a doping concentration of 3x10(17) cm(-3), a thicker silicon film (300 nm) must be used. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Schwank, JR (reprint author), Sandia Natl Labs, POB 5800,MS-1083, Albuquerque, NM 87185 USA. NR 16 TC 27 Z9 31 U1 2 U2 6 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1999 VL 46 IS 6 BP 1809 EP 1816 DI 10.1109/23.819158 PN 1 PG 8 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 279RG UT WOS:000085058500072 ER PT J AU Manfredi, PF Abbott, B Clark, A DeWitt, J Dow, S Eisner, A Fan, Q Frey, A Johnson, R Karcher, A Kipnis, I Kroeger, W Leona, A Levi, M Mandelli, E Luo, L Morsani, F Nyman, M Perazzo, A Pedrali-Noy, M Re, V Roe, N Spencer, N AF Manfredi, PF Abbott, B Clark, A DeWitt, J Dow, S Eisner, A Fan, Q Frey, A Johnson, R Karcher, A Kipnis, I Kroeger, W Leona, A Levi, M Mandelli, E Luo, L Morsani, F Nyman, M Perazzo, A Pedrali-Noy, M Re, V Roe, N Spencer, N TI Functional characteristics and radiation tolerance of AToM, the front-end chip of BaBar Silicon Vertex Tracker SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1998 Nuclear Science Symposium (NSS) CY NOV 08-14, 1998 CL TORONTO, CANADA SP IEEE AB The readout chip designed to process the microstrip signals in the BaBar Silicon Vertex Tracker (SVT), after being realized twice in a radsoft technology has been transferred into the final radhard process. So far the circuit has gone through four different radhard submissions, one aiming at providing a preliminary insight into the characteristics of the radhard chip, the other ones constituting pre-production and production runs. Chips from these submissions have undergone a thorough set of tests addressing functional aspects, noise parameters and effects of radiation on signal and noise behavior. The present paper discusses the results of these tests and describes the final version of the circuit which has been proven to successfully meet the experiment requirements. C1 Univ Pavia, Dipartimento Elettr, Ist Nazl Fis Nucl, I-27100 Pavia, Italy. EO Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Calif Santa Cruz, Santa Cruz Inst Particle Phys, Santa Cruz, CA 95064 USA. Ist Nazl Fis Nucl, I-56010 S Piero A Grado, Italy. Univ Bergamo, Dipartimento Ingn, I-24044 Dalmine, BG, Italy. RP Manfredi, PF (reprint author), Univ Pavia, Dipartimento Elettr, Ist Nazl Fis Nucl, Via Palestro 3, I-27100 Pavia, Italy. OI Re, Valerio/0000-0003-0697-3420 NR 8 TC 6 Z9 6 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 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1999 VL 46 IS 6 BP 1865 EP 1870 DI 10.1109/23.819242 PN 2 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 279RH UT WOS:000085058600002 ER PT J AU Dorfan, D Dubbs, T Grillo, AA Ipe, NE Mao, S Rowe, W Sadrozinski, HFW Seiden, A Spencer, E Stromberg, S Wichmann, R AF Dorfan, D Dubbs, T Grillo, AA Ipe, NE Mao, S Rowe, W Sadrozinski, HFW Seiden, A Spencer, E Stromberg, S Wichmann, R TI Measurement of dose rate dependence of radiation induced damage to the current gain in bipolar transistors SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1998 Nuclear Science Symposium (NSS) CY NOV 08-14, 1998 CL TORONTO, CANADA SP IEEE ID DEVICES AB We report the study of radiation induced change in the current gain of bipolar transistors for three different gamma dose rates. The dose rates differed by a factor of 60 with the lowest close to that anticipated for the LHC, and the highest at a rate we have been routinely using for radiation damage tests. The maximum dose attained was 200kRad, which is high enough to compare with other measurements. The importance of annealing high dose rate data is demonstrated. C1 Univ Calif Santa Cruz, Santa Cruz Inst Particle Phys, Santa Cruz, CA 95064 USA. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Dorfan, D (reprint author), Univ Calif Santa Cruz, Santa Cruz Inst Particle Phys, Santa Cruz, CA 95064 USA. NR 16 TC 5 Z9 5 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 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1999 VL 46 IS 6 BP 1884 EP 1890 DI 10.1109/23.819246 PN 2 PG 7 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 279RH UT WOS:000085058600006 ER PT J AU Fabris, L Allen, PG Bucher, JJ Edelstein, NM Landis, DA Madden, NW Shuh, DK AF Fabris, L Allen, PG Bucher, JJ Edelstein, NM Landis, DA Madden, NW Shuh, DK TI Fast peak detector stretchers for use in XAFS applications SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1998 Nuclear Science Symposium (NSS) CY NOV 08-14, 1998 CL TORONTO, CANADA SP IEEE AB In this paper we present two different design approaches to the implementation of fast peak detector-stretchers for Xray absorption fine structure fluorescence applications (XAFS). After describing the motivations for using peak detector-stretchers in high rate applications, we discuss in detail the design and benefits of their use in a modern nuclear spectroscopy system. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Fabris, L (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, 1 Cyclotron Rd, Berkeley, CA 94720 USA. RI Fabris, Lorenzo/E-4653-2013 OI Fabris, Lorenzo/0000-0001-5605-5615 NR 3 TC 6 Z9 6 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 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1999 VL 46 IS 6 BP 1891 EP 1893 DI 10.1109/23.819247 PN 2 PG 3 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 279RH UT WOS:000085058600007 ER PT J AU Mahler, GJ Radeka, V Schaknowski, NA Smith, GC Yu, B Zojceski, Z AF Mahler, GJ Radeka, V Schaknowski, NA Smith, GC Yu, B Zojceski, Z TI A new thermal neutron detector for protein crystallography SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1998 Nuclear Science Symposium (NSS) CY NOV 08-14, 1998 CL TORONTO, CANADA SP IEEE AB A new position-sensitive detector is being developed for protein crystallography studies at a spallation source. Based on eight, independent, wire proportional chamber segments housed in a curved pressure vessel, the device covers a scattering angle of 120 degrees, and has a collecting area of 1.5m by 20cm. The position resolution will be about 1.3 mm FWHM, with a total counting rate in excess of one million per second. Timing resolution, essential for a spallation source application, is of order 1 mu s and provides neutron energy determination that is well suited for crystallography. Advanced features of this device include a digital centroid finding scheme, a seamless readout between segments, and a wire array design that minimizes anode modulation. Details of the mechanical design are given, together with digital centroid measurements that illustrate accurate, uniform response. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. RP Brookhaven Natl Lab, Upton, NY 11973 USA. NR 6 TC 7 Z9 7 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9499 EI 1558-1578 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1999 VL 46 IS 6 BP 1916 EP 1919 DI 10.1109/23.819253 PN 2 PG 4 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 279RH UT WOS:000085058600013 ER PT J AU Park, IJ Cho, HS Hong, WS Perez-Mendez, V Kadyk, J AF Park, IJ Cho, HS Hong, WS Perez-Mendez, V Kadyk, J TI Moisture proof columnar cesium iodide (CsI) layers for gas avalanche microdetectors SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1998 Nuclear Science Symposium (NSS) CY NOV 08-14, 1998 CL TORONTO, CANADA SP IEEE AB Cesium iodide columnar layers having a diameter of approximate to 3 mu m, and wall spacing of approximate to 1 mu m act as secondary electron emitters and can be used for detection of radiation: charged particles, X-rays and gamma rays. With a large enough electric field across the columnar layers, approximate to 400 mu m in thickness, gas avalanche gain is evident when placed in a suitable gas, such as P10 or argon-ethane mixtures. The cesium iodide columns are damaged by ambient moisture. This damage can be prevented by evaporating protective layers of insoluble, low boiling point inorganic materials, such as mercuric iodide. Columnar layers with 20 nm coatings of mercuric iodide yield more than 30,000 electrons on average when traversed by electrons from a Sr-90 beta source. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Engn, Berkeley, CA 94720 USA. RP Park, IJ (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Phys, Berkeley, CA 94720 USA. NR 7 TC 1 Z9 1 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 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1999 VL 46 IS 6 BP 1938 EP 1942 DI 10.1109/23.819258 PN 2 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 279RH UT WOS:000085058600018 ER PT J AU Castoldi, A Gatti, E Guazzoni, C Longoni, A Rehak, P Struder, L AF Castoldi, A Gatti, E Guazzoni, C Longoni, A Rehak, P Struder, L TI Analysis and characterisation of the confining mechanism of the Controlled-Drift Detector SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1998 Nuclear Science Symposium (NSS) CY NOV 08-14, 1998 CL TORONTO, CANADA SP IEEE ID DEVICE AB The Controlled-Drift Detector is a recently designed position-sensing X-ray detector. It operates by switching between integration and drift mode. The basic idea is to generate potential wells within the otherwise linear drift potential. During the integration mode signal electrons are being accumulated within these wells. The removal of the barriers in an externally controlled way restores a uniform drift field that sweeps the electrons towards the readout anodes. The height of the confining barrier depends on the drift field and on the amplitude of the potential perturbation at the surface. An experimental study of the charge handling capability has been carried out as a function of the amplitude of the surface perturbation (up to 2.1 V) and as a function of the drift field (250-400 V/cm). The study provides a sensitive measurement of the actual potential barrier of the integration well in different operating conditions. A detailed analysis and characterisation of the mechanisms to confine the signal electrons in the 3D well is presented. For a drift field of 300 V/cm, storage of more than 10(5) electrons in 180 x 180 mu m(2) pixels has been achieved with 1.67 V surface perturbation. C1 Politecn Milan, Dipartimento Ingn Nucl, CeSNEF, I-20133 Milan, Italy. Politecn Milan, Dipartimento Elettr & Informaz, I-20133 Milan, Italy. Brookhaven Natl Lab, Upton, NY 11973 USA. MPI Halbleiterlabor, D-81245 Munich, Germany. RP Castoldi, A (reprint author), Politecn Milan, Dipartimento Ingn Nucl, CeSNEF, Pza L da Vinci 32, I-20133 Milan, Italy. RI Guazzoni, Chiara/A-5070-2008 OI Guazzoni, Chiara/0000-0001-6399-8670 NR 5 TC 6 Z9 6 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 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1999 VL 46 IS 6 BP 1943 EP 1947 DI 10.1109/23.819259 PN 2 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 279RH UT WOS:000085058600019 ER PT J AU Cannara, R Dezillie, B Dubbs, T Hancock, J Kroeger, W Li, Z Nissen, T Onodera, M Rowe, WA Sadrozinski, HFW Wan, QS Zhao, LJ AF Cannara, R Dezillie, B Dubbs, T Hancock, J Kroeger, W Li, Z Nissen, T Onodera, M Rowe, WA Sadrozinski, HFW Wan, QS Zhao, LJ TI Depletion voltage and charge collection for highly irradiated silicon microstrip detectors with various initial resistivities SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1998 Nuclear Science Symposium (NSS) CY NOV 08-14, 1998 CL TORONTO, CANADA SP IEEE AB We have irradiated p-on-n silicon microstrip detectors of initial bulk resistivity between 0.2 and 2.7 k Omega-cm with 55MeV protons to fluences of 0.7, 2 and 11x10(13) p/cm(2) (equivalent to twice the fluence in high energy protons), and have measured the depletion voltage before and after irradiation using C-V methods. In addition, we have measured the charge collection of minimum ionization on a single strip with a fast amplifier as a function of bias voltage. We compare the depletion voltage deduced from both methods for samples with different initial resistivities. C1 Univ Calif Santa Cruz, SCIPP, Santa Cruz, CA 95064 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Cannara, R (reprint author), Univ Calif Santa Cruz, SCIPP, Santa Cruz, CA 95064 USA. NR 7 TC 0 Z9 0 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 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1999 VL 46 IS 6 BP 1964 EP 1968 DI 10.1109/23.819263 PN 2 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 279RH UT WOS:000085058600023 ER PT J AU Derenzo, SE Klintenberg, M Weber, MJ AF Derenzo, SE Klintenberg, M Weber, MJ TI Ab-initio cluster calculations of hole formation and trapping in PbF2 and PbF4 SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1998 Nuclear Science Symposium (NSS) CY NOV 08-14, 1998 CL TORONTO, CANADA SP IEEE AB We have used nb-initio quantum chemistry computer codes to model the formation of holes and the energy barriers for their diffusion in two lead fluoride hosts of potential interest for scintillation-PbF2 and PbF4. The crystals were modeled by Pb24F48 and Pb14F56 atomic clusters embedded in arrays of several thousand point charges to reproduce the Madelung potential to an accuracy of several mV throughout the cluster. Cubic PbF2 has the same crystal structure as CaF2, however their electronic structures are different. It is known experimentally that in CaF2 holes travel easily along rows of F atoms which accounts for the high luminous efficiency of the scintillator CaF2:Eu. In contrast, these calculations show that in PbF2 holes are trapped on the Pb atoms by an energy barrier of similar to 1 eV. This result is consistent with the failure of PbF2 as an activated scintillator. Similar calculations on the experimentally unexplored crystal PbF4 predict that the holes are trapped on F atoms with an energy barrier of similar to 1 eV and is therefore not a promising host for an activated scintillator. These computational techniques can be applied to other crystals to find those with mobile holes for new heavy-atom scintillators and solid-state detectors. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Derenzo, SE (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 8 TC 1 Z9 1 U1 1 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1999 VL 46 IS 6 BP 1969 EP 1973 DI 10.1109/23.819264 PN 2 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 279RH UT WOS:000085058600024 ER PT J AU Smith, MC Bryan, WL Smith, D Jagadish, U McMillan, D Walker, J Young, GR Oskarsson, A Osterman, L Greene, V Nikkinen, L AF Smith, MC Bryan, WL Smith, D Jagadish, U McMillan, D Walker, J Young, GR Oskarsson, A Osterman, L Greene, V Nikkinen, L TI A front-end electronics module for the PHENIX Pad Chamber SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1998 Nuclear Science Symposium (NSS) CY NOV 08-14, 1998 CL TORONTO, CANADA SP IEEE AB A front-end electronics module (FEM) has been developed for the PHENIX Pad Chamber. The module's control functions are performed by the heap manager unit, an FPGA-based circuit on the FEM. Each FEM processes signals from 2160 channels of front-end electronics (FEE). Data readout and formatting are performed by an additional FPGA-based circuit on the FEM. Three external systems provide initialization timing, and data information via serial interfaces. This paper discusses the application of the heap manager, data formatter, and serial interfaces to meet the specific control and data readout needs of the Pad Chamber subsystem. Unit functions, interfaces, timing, data format, and communication rates will be discussed. In addition, subsystem issues regarding mode control, serial architecture and functions, error handling and FPGA implementation and programming will be presented. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Lund, S-22362 Lund, Sweden. Vanderbilt Univ, Nashville, TN 37235 USA. McGill Univ, Montreal, PQ, Canada. RP Smith, MC (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 2 TC 3 Z9 3 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 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1999 VL 46 IS 6 BP 1998 EP 2002 DI 10.1109/23.819270 PN 2 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 279RH UT WOS:000085058600030 ER PT J AU Berenyi, A Chen, HK Dao, K Dow, SF Gehrig, SK Gill, MS Grace, C Jared, RC Johnson, JK Karcher, A Kasen, D Kirsten, FA Kral, JF LeClerc, CM Levi, ME von der Lippe, H Liu, TH Marks, KM Meyer, AB Minor, R Montgomery, AH Romosan, A AF Berenyi, A Chen, HK Dao, K Dow, SF Gehrig, SK Gill, MS Grace, C Jared, RC Johnson, JK Karcher, A Kasen, D Kirsten, FA Kral, JF LeClerc, CM Levi, ME von der Lippe, H Liu, TH Marks, KM Meyer, AB Minor, R Montgomery, AH Romosan, A TI Design and implementation of the level 1 charged particle trigger for the BABAR detector SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1998 Nuclear Science Symposium (NSS) CY NOV 08-14, 1998 CL TORONTO, CANADA SP IEEE AB The environment of the high-luminosity PEP-II machine poses unique design challenges for the trigger system of the BABAR detector. These led to the adoption of a real-time parallel pipelined architecture for the trigger electronics which departs significantly from previous implementations at conventional e(+)e(-) experiments. One challenge for the trigger designer lies in detecting low multiplicity physics events with high efficiency while keeping the background rate within the data acquisition limits. To achieve this difficult task, creative and innovative high-speed trigger algorithms were designed, simulated and implemented in Field Programmable Gate Arrays, using advanced CAD/CAE tools. The simulation results indicate that these algorithms will be able to perform all required tasks quickly and efficiently. This paper describes the design of the Level 1 Drift Chamber Trigger System of the BABAR detector, including the trigger algorithms, design and test methodology of the implementation, as well as test and simulation results. C1 EO Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Berenyi, A (reprint author), EO Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RI Montgomery, Alexander/B-4969-2009 OI Montgomery, Alexander/0000-0003-4166-0534 NR 9 TC 3 Z9 3 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 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1999 VL 46 IS 6 BP 2006 EP 2010 DI 10.1109/23.819272 PN 2 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 279RH UT WOS:000085058600032 ER PT J AU Bennett, MJ Bernardin, J Boissevain, J Britton, C Chang, J Clark, D Conway, R Cunningham, R Emery, M Ericson, N Fung, SY Hahn, S van Hecke, H Jaffe, D Kang, JH Kim, SY Kim, YG Lind, R Marek, L McCabe, K Moore, T Park, JH Richardson, G Ryu, SS Schlei, B Seto, R Shiina, T Simon-Gillo, J Simpson, M Smith, G Sullivan, JP Takahashi, Y Wintenberg, A Xu, G AF Bennett, MJ Bernardin, J Boissevain, J Britton, C Chang, J Clark, D Conway, R Cunningham, R Emery, M Ericson, N Fung, SY Hahn, S van Hecke, H Jaffe, D Kang, JH Kim, SY Kim, YG Lind, R Marek, L McCabe, K Moore, T Park, JH Richardson, G Ryu, SS Schlei, B Seto, R Shiina, T Simon-Gillo, J Simpson, M Smith, G Sullivan, JP Takahashi, Y Wintenberg, A Xu, G TI Simulations of the performance of the MVD in PHENIX SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1998 Nuclear Science Symposium (NSS) CY NOV 08-14, 1998 CL TORONTO, CANADA SP IEEE ID COLLISIONS AB The PHENIX Multiplicity Vertex Detector (MVD) provides event characterization, a centrality trigger, collision vertex position, and measures fluctuations in charged particle multiplicities. The design criteria include a large rapidity coverage, good azimuthal coverage and granularity, minimizing material in the electron arm acceptance, and minimizing costs. The MVD contains two concentric barrels of Si strip detectors with two disk-shaped Si pad detector endcaps. Simulations will show that the vertex position can be located to within a few hundred microns using hits in the barrels. A channel multiplicity signal is formed for use in the Level-1 trigger. The effect of the expected discriminator performance on this trigger signal will be shown. The pad and strip detectors are read-out with identical electronics. The influence of the performance of the electronics on the detector's performance will be discussed. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87544 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Calif Riverside, Riverside, CA 92521 USA. Univ Alabama, Huntsville, AL 35899 USA. Yonsei Univ, Seoul 120749, South Korea. RP Bennett, MJ (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87544 USA. RI Simpson, Michael/A-8410-2011 OI Simpson, Michael/0000-0002-3933-3457 NR 7 TC 1 Z9 1 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 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1999 VL 46 IS 6 BP 2022 EP 2026 DI 10.1109/23.819275 PN 2 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 279RH UT WOS:000085058600035 ER PT J AU Albert, J Bajic, A Bard, R Beaulieu, M Blinov, V Boyarski, A Broomer, B Coupal, D Dal Corso, F Dolinsky, S Dorfan, D Dow, S Dubrovin, M Dusatko, J Erdos, E Faccini, R Fernandez, JP Ford, WT Galeazzi, F Haller, G Innes, W Jawahery, A Kreig, H Lankford, AJ Levi, M von der Lippe, H MacFarlane, DB Martin, JP Momayezi, M Morandin, M Morii, M Nelson, D Nguyen, P Palrang, M Roy, J Sadrozinski, H Schumm, B Sciolla, G Seiden, A Smith, AJS Spencer, E Soha, A Taras, P Varnes, E Weinstein, A Wilson, F Yushkov, A AF Albert, J Bajic, A Bard, R Beaulieu, M Blinov, V Boyarski, A Broomer, B Coupal, D Dal Corso, F Dolinsky, S Dorfan, D Dow, S Dubrovin, M Dusatko, J Erdos, E Faccini, R Fernandez, JP Ford, WT Galeazzi, F Haller, G Innes, W Jawahery, A Kreig, H Lankford, AJ Levi, M von der Lippe, H MacFarlane, DB Martin, JP Momayezi, M Morandin, M Morii, M Nelson, D Nguyen, P Palrang, M Roy, J Sadrozinski, H Schumm, B Sciolla, G Seiden, A Smith, AJS Spencer, E Soha, A Taras, P Varnes, E Weinstein, A Wilson, F Yushkov, A TI Electronics for the BaBar central drift chamber SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1998 Nuclear Science Symposium (NSS) CY NOV 08-14, 1998 CL TORONTO, CANADA SP IEEE AB The central drift chamber for the BaBar detector at the SLAG B-factory is based on a hexagonal cell design with 7104 cells arranged in 40 layers and drift gas Helium:isobutane (80%:20%). Performance optimization and integration requirements led to an electronics design that mounts the amplifier-discriminator and digitizing circuitry directly on the endplate. High channel density is achieved using a 4-channel custom amplifier-discriminator IC and an 8-channel custom CMOS TDC/FADC IC on a single circuit board. Data read from the front ends are multiplexed on 4 fiber optic links, and prompt trigger data are sent out continuously on 24 links. Analysis of cosmic ray data demonstrates that the electronics design meets the performance goals for the BaBar drift chamber. The final electronics were installed on the drift chamber in July, 1998. Installation of BaBar on beamline is scheduled for March, 1999. C1 Budker Inst Nucl Phys, Novosibirsk 630090, Russia. Univ Calif Irvine, Irvine, CA 92697 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Colorado, Boulder, CO 80309 USA. Ist Nazl Fis Nucl, I-35131 Padua, Italy. Univ Padua, I-35131 Padua, Italy. Univ Maryland, College Pk, MD 20742 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Montreal, Montreal, PQ H3C 3J7, Canada. Princeton Univ, Princeton, NJ 08544 USA. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Albert, J (reprint author), Budker Inst Nucl Phys, Novosibirsk 630090, Russia. RI Morandin, Mauro/A-3308-2016; OI Morandin, Mauro/0000-0003-4708-4240; Dolinsky, Sergei/0000-0002-2789-453X; Galeazzi, Fulvio/0000-0002-6830-9982; Faccini, Riccardo/0000-0003-2613-5141 NR 4 TC 2 Z9 2 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1999 VL 46 IS 6 BP 2027 EP 2032 DI 10.1109/23.819276 PN 2 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 279RH UT WOS:000085058600036 ER PT J AU Gruber, GJ Moses, WW Derenzo, SE AF Gruber, GJ Moses, WW Derenzo, SE TI Monte Carlo simulation of breast tumor imaging properties with compact, discrete gamma cameras SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1998 Medical Imaging Conference CY NOV 12-14, 1998 CL TORONTO, CANADA ID SCINTIMAMMOGRAPHY AB We describe Monte Carlo simulation results for breast tumor imaging using a compact, discrete gamma camera. The simulations were designed to analyze and optimize camera design, particularly collimator configuration and detector pixel size. Simulated planar images of 5-15 mm diameter tumors in a phantom patient (including a breast, torso, and heart) were generated for imaging distances of 5-55 mm, pixel sizes of 2x2-4x4 mm(2), and hexagonal and square hole collimators with sensitivities from 4000 to 16,000 counts/mCi/sec. Other factors considered included T/B (tumor-to-background tissue uptake ratio) and detector energy resolution. Image properties were quantified by computing the observed tumor fwhm (full-width at half-maximum) and S/N (sum of detected tumor events divided by the statistical noise). Results suggest that hexagonal and square hole collimators perform comparably, that higher sensitivity collimators provide higher tumor S/N with little increase in the observed tumor fwhm, that smaller pixels only slightly improve tumor fwhm and S/N, and that improved detector energy resolution has little impact on either the observed tumor fwhm or the observed tumor S/N. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Gruber, GJ (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. NR 13 TC 31 Z9 31 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 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1999 VL 46 IS 6 BP 2119 EP 2123 DI 10.1109/23.819292 PN 3 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 279RJ UT WOS:000085058700011 ER PT J AU Mescher, MJ Hoburg, JF Schlesinger, TE James, RB AF Mescher, MJ Hoburg, JF Schlesinger, TE James, RB TI Analyses on the measurement of leakage currents in CdZnTe radiation detectors SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article DE cadmium zinc telluride; electrostatic field modeling; leakage current; surface passivation ID CDTE SURFACES; PERFORMANCE; PASSIVATION; OXIDATION; ETCHANTS AB Models that place design constraints on devices which are used to measure the leakage currents in high-resistivity semiconductor materials are presented. If these design constraints are met, these models can then be used to quantitatively predict the surface sheet resistance of devices which are dominated by surface leakage currents. As a result, a means is provided to directly compare passivation techniques which are developed to decrease surface leakage currents. Furthermore, these models illustrate the necessity for inclusion of relevant geometrical data on sample size and shape and electrode configuration when reporting results of surface passivation techniques. These models specifically examine the case where a de potential is applied across two electrodes on the surface of a semiconductor substrate which has a surface layer with lower resistivity than the bulk material. We describe several of the more common configurations used in analyzing passivation techniques for compounds of Cd1-xZnxTe (CZT) used for room-temperature radiation detection. C1 Carnegie Mellon Univ, Dept Elect & Comp Engn, Pittsburgh, PA 15213 USA. Sandia Natl Labs, Livermore, CA USA. RP Mescher, MJ (reprint author), Carnegie Mellon Univ, Dept Elect & Comp Engn, Pittsburgh, PA 15213 USA. NR 19 TC 12 Z9 13 U1 0 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1999 VL 46 IS 6 BP 2289 EP 2296 DI 10.1109/23.819319 PN 4 PG 8 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 279RL UT WOS:000085058900003 ER PT J AU Das, B Pitzer, KS AF Das, B Pitzer, KS TI Thermodynamics of aqueous solutions of p-toluenesulphonic acid and its some alkali metal salts in the temperature range of 298.15 K to 353.15 K SO INDIAN JOURNAL OF CHEMISTRY SECTION A-INORGANIC BIO-INORGANIC PHYSICAL THEORETICAL & ANALYTICAL CHEMISTRY LA English DT Article ID ELECTROLYTES AB The available experimental osmotic coefficients for aqueous solutions of p-toluenesulphonic acid and its lithium sodium and potassium salts have been analyzed in the framework of the Pitzer ion-interaction model in the temperature range of 298.15 K to 353.15 K. The standard deviation of fit (in the osmotic coefficient) ranges from 0.0013 to 0.0044. Parameters derived from the fit have been used to calculate the activity coefficients. These activity coefficients are compared with those reported earlier from osmotic coefficients by an integration procedure and a good agreement is found. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Das, B (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 8 TC 2 Z9 2 U1 0 U2 0 PU NATL INST SCIENCE COMMUNICATION PI NEW DELHI PA DR K S KRISHNAN MARG, NEW DELHI 110 012, INDIA SN 0376-4710 J9 INDIAN J CHEM A JI Indian J. Chem. Sect A-Inorg. Bio-Inorg. Phys. Theor. Anal. Chem. PD DEC PY 1999 VL 38 IS 12 BP 1261 EP 1263 PG 3 WC Chemistry, Multidisciplinary SC Chemistry GA 278EN UT WOS:000084975100013 ER PT J AU Seppanen, OA Fisk, WJ Mendell, MJ AF Seppanen, OA Fisk, WJ Mendell, MJ TI Association of ventilation rates and CO2 concentrations with health and other responses in commercial and institutional buildings SO INDOOR AIR-INTERNATIONAL JOURNAL OF INDOOR AIR QUALITY AND CLIMATE LA English DT Article DE ventilation rates; carbon dioxide; health effects; SBS symptoms; air exchange rate; relative risks ID INDOOR AIR-QUALITY; OFFICE BUILDINGS; PERSONAL FACTORS; EXCHANGE-RATE; SYNDROME SBS; SYMPTOMS; SCHOOLS; RISK; REQUIREMENTS; TEMPERATURE AB This paper reviews current literature on the associations of ventilation rates and carbon dioxide concentrations in nonresidential and non-industrial buildings (primarily offices) with health and other human outcomes. Twenty studies, with close to 30,000 subjects, investigated the association of ventilation rates with human responses, and 21 studies, with over 30,000 subjects, investigated the association of carbon dioxide concentration with these responses. Almost all studies found that ventilation rates below 10 Ls(-1) per person in all building types were associated with statistically significant worsening in one or more health or perceived air quality outcomes. Some studies determined that increases in ventilation rates above 10 Ls(-1) per person, up to approximately 20 Ls(-1) per person, were associated with further significant decreases in the prevalence of sick building syndrome (SBS) symptoms or with further significant improvements in perceived air quality. The carbon dioxide studies support these findings. About half of the carbon dioxide studies suggest that the risk of sick building syndrome symptoms continued to decrease significantly with decreasing carbon dioxide concentrations below 800 ppm. The ventilation studies reported relative risks of 1.5-2 for respiratory illnesses and 1.1-6 for sick building syndrome symptoms for low compared to high low ventilation rates. C1 Lawrence Berkeley Natl Lab, Indoor Environm Dept, Environm Energy Technol Div, Berkeley, CA 94720 USA. Helsinki Univ Technol, Lab Heating Ventilating & Air Conditioning, Helsinki, Finland. NIOSH, Cincinnati, OH 45226 USA. RP Fisk, WJ (reprint author), Lawrence Berkeley Natl Lab, Indoor Environm Dept, Environm Energy Technol Div, Berkeley, CA 94720 USA. NR 94 TC 241 Z9 246 U1 6 U2 52 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0905-6947 J9 INDOOR AIR JI Indoor Air-Int. J. Indoor Air Qual. Clim. PD DEC PY 1999 VL 9 IS 4 BP 226 EP 252 DI 10.1111/j.1600-0668.1999.00003.x PG 27 WC Construction & Building Technology; Engineering, Environmental; Public, Environmental & Occupational Health SC Construction & Building Technology; Engineering; Public, Environmental & Occupational Health GA 320GN UT WOS:000087393600003 PM 10649857 ER PT J AU Faulkner, D Fisk, WJ Sullivan, DP Wyon, DP AF Faulkner, D Fisk, WJ Sullivan, DP Wyon, DP TI Ventilation efficiencies of desk-mounted task/ambient conditioning systems SO INDOOR AIR-INTERNATIONAL JOURNAL OF INDOOR AIR QUALITY AND CLIMATE LA English DT Article DE task/ambient conditioning; air change effectiveness; pollutant removal efficiency; ventilation; indoor air quality ID INDOOR AIR-FLOW; POLLUTANT REMOVAL; ROOM AB In laboratory experiments, we investigated two task/ambient conditioning systems with air supplied from desk-mounted air outlets to efficiently ventilate the breathing zone of heated manikins seated at desks. In most experiments, the task conditioning systems provided outside air while a conventional ventilation system provided additional space cooling but no outside air. Air change effectiveness (i.e., exhaust air age divided by age of air at the manikin's face) was measured with a tracer gas step-up procedure. Other tracer gases simulated the release of pollutants from nearby occupants and from the floor covering, and the associated pollutant removal efficiencies (i.e., exhaust air concentrations divided by concentrations at manikin's face) were calculated. High values of air change effectiveness (similar to 1.3 to 1.9) and high values of pollutant removal efficiency (similar to 1.2 to 1.6) were measured when these task conditioning systems supplied 100% outdoor air at a flow rate of 7 to 9 L s(-1) per occupant. Air change effectiveness was reasonably well correlated with the pollutant removal efficiency. Overall, the experimental data suggest that these task/ambient conditioning systems can be used to improve ventilation and air quality or to save energy while maintaining a typical level of IAQ at the breathing zone. C1 Lawrence Berkeley Nat Lab, Indoor Environm Dept, Berkeley, CA 94720 USA. Johnson Controls Inc, Controls Grp, Milwaukee, WI 53201 USA. RP Faulkner, D (reprint author), Lawrence Berkeley Nat Lab, Indoor Environm Dept, 1 Cyclotron Rd,MS 90-3058, Berkeley, CA 94720 USA. NR 20 TC 30 Z9 30 U1 2 U2 6 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0905-6947 J9 INDOOR AIR JI Indoor Air-Int. J. Indoor Air Qual. Clim. PD DEC PY 1999 VL 9 IS 4 BP 273 EP 281 DI 10.1111/j.1600-0668.1999.00007.x PG 9 WC Construction & Building Technology; Engineering, Environmental; Public, Environmental & Occupational Health SC Construction & Building Technology; Engineering; Public, Environmental & Occupational Health GA 320GN UT WOS:000087393600007 PM 10649861 ER PT J AU Dell'Orco, P Eaton, E McInroy, R Flesner, R Walker, T Muske, K AF Dell'Orco, P Eaton, E McInroy, R Flesner, R Walker, T Muske, K TI Hydrothermal treatment of C-N-O-H wastes: Reaction kinetics and pathways for hydrolysis products of high explosives SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID SUPERCRITICAL WATER; HYDROGEN-PEROXIDE; FORMIC-ACID; DECOMPOSITION; OXIDATION; HMX AB Bench-scale studies demonstrated the efficacy of hydrothermal oxidation for the treatment of wastes derived from the alkaline hydrolysis of the high explosive PBX 9404 (94% HMX, 3% nitrocellulose, and 3% chloroethyl phosphate). Specifically, chemical kinetics studies were used to deduce major global reaction pathways, End to develop a kinetic model. Although the hydrolysis liquor is a complicated waste matrix, a three-parameter kinetic model captured major reaction paths. The kinetic model used total organic carbon (TOC) as a bulk parameter for dissolved organic materials, while NOx- was used to represent the oxidized nitrogen species in solution (NO2- and NO3-). With the use of the kinetic model, an optimal treatment strategy using two oxidation stages was derived. The first stage involved balancing NOx- and O-2 redox chemistry to minimize aqueous nitrogen in the effluent, while the second stage mineralized the remaining TOC. C1 SmithKline Beecham Pharmaceut, King Of Prussia, PA 19406 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Villanova Univ, Dept Chem Engn, Villanova, PA 19085 USA. RP Dell'Orco, P (reprint author), SmithKline Beecham Pharmaceut, 709 Swedeland Rd UE1125, King Of Prussia, PA 19406 USA. NR 28 TC 9 Z9 9 U1 1 U2 7 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 DEC PY 1999 VL 38 IS 12 BP 4585 EP 4593 DI 10.1021/ie9901022 PG 9 WC Engineering, Chemical SC Engineering GA 263LV UT WOS:000084126900010 ER PT J AU Granite, EJ Pennline, HW Hoffman, JS AF Granite, EJ Pennline, HW Hoffman, JS TI Effects of photochemical formation of mercuric oxide SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article AB The photochemistry of elemental mercury and oxygen was examined using quartz flow reactors. Germicidal bulbs were used as the source of 253.7-nm ultraviolet radiation. The formation of mercuric oxide, as visually detected by yellow-brown stains on the quartz walls, was confirmed by both ICP-AES and SEM-EDX analyses. In addition, a high surface area calcium silicate sorbent was used to capture the mercuric oxide in one of the experiments. The implications of mercuric oxide formation with respect to analysis of gases for mercury content, atmospheric reactions, and direct; ultraviolet irradiation of flue gas for mercury sequestration are discussed. C1 US DOE, Fed Energy Technol Ctr, Pittsburgh, PA 15236 USA. RP Granite, EJ (reprint author), US DOE, Fed Energy Technol Ctr, POB 10940, Pittsburgh, PA 15236 USA. NR 23 TC 41 Z9 42 U1 1 U2 5 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 DEC PY 1999 VL 38 IS 12 BP 5034 EP 5037 DI 10.1021/ie9904495 PG 4 WC Engineering, Chemical SC Engineering GA 263LV UT WOS:000084126900061 ER PT J AU Nishiyama, Y Okano, T Langan, P Chanzy, H AF Nishiyama, Y Okano, T Langan, P Chanzy, H TI High resolution neutron fibre diffraction data on hydrogenated and deuterated cellulose SO INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES LA English DT Article; Proceedings Paper CT 19th International Carbohydrate Symposium CY AUG 09-14, 1998 CL SAN DIEGO, CALIFORNIA DE cellulose; neutron high-angle fibre diffraction; deuteration ID D-CELLOTETRAOSE HEMIHYDRATE; CRYSTAL-STRUCTURE; NATIVE CELLULOSE; PACKING ANALYSIS; ELECTRON-DIFFRACTION; FIBER DIFFRACTION; I-ALPHA; POLYSACCHARIDES; MODEL AB High-resolution fibre neutron diffraction data were recorded from cellulose samples on a D19 diffractometer at the Institut Laue-Langevin (Grenoble). Highly crystalline cellulose I samples from Cladophora (cellulose I alpha + I beta) or Halocynthia (cellulose IF) origin were prepared in the form of oriented films. Samples were studied in a hydrogenated form and in a hydrogen-deuterium exchanged deuterated form corresponding to all OH moieties being replaced by ODs. These samples, which diffracted to a resolution of around 0.9 Angstrom, save diffraction diagrams consisting of several hundred independent diffraction spots. Crystalline cellulose II fibres resulting from the mercerization of flax were also studied in a hydrogenated form using NaOH/H2O as mercerizing medium and in a deuterated form using NaOD/D2O. Both of these samples diffracted to around 1.2 Angstrom, giving fibre diffraction diagrams slightly less reserved than those of cellulose I, but still consisting of more than one hundred independent diffraction spots. For cellulose I as well as for cellulose II, significant differences between the hydrogenated and deuterated patterns were observed and recorded. These new data should lead to improved structures for cellulose and direct identification of the position of hydrogen atoms involved in hydrogen bonding. (C) 1999 Elsevier Science B.V. All rights reserved. C1 CNRS, Ctr Rech Macromol Vegetales, F-38041 Grenoble 9, France. Inst Max Von Laue Paul Langevin, F-38042 Grenoble, France. Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. Univ Tokyo, Grad Sch Agr & Life Sci, Tokyo 1138256, Japan. RP Chanzy, H (reprint author), CNRS, Ctr Rech Macromol Vegetales, BP 53, F-38041 Grenoble 9, France. RI Nishiyama, Yoshiharu/A-3492-2012; Chanzy, Henri/A-3526-2012; Langan, Paul/N-5237-2015 OI Nishiyama, Yoshiharu/0000-0003-4069-2307; Langan, Paul/0000-0002-0247-3122 NR 29 TC 23 Z9 23 U1 1 U2 19 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0141-8130 J9 INT J BIOL MACROMOL JI Int. J. Biol. Macromol. PD DEC 1 PY 1999 VL 26 IS 4 BP 279 EP 283 DI 10.1016/S0141-8130(99)00094-X PG 5 WC Biochemistry & Molecular Biology; Chemistry, Applied; Polymer Science SC Biochemistry & Molecular Biology; Chemistry; Polymer Science GA 255LP UT WOS:000083670500010 PM 10569290 ER PT J AU Hadley, MA Morris, GJ Richards, G Upadhyay, PC AF Hadley, MA Morris, GJ Richards, G Upadhyay, PC TI Frequency response of bodies with combined convective and radiative heat transfer SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article DE mixed-mode heat transfer; temperature sensors; frequency response of sensors AB An analytical model for solving the problem of frequency response of bodies with combined convective and radiative heat transfer is presented. The issue of two conflicting types of conclusions existing in the literature regarding the effect of radiative heat transfer on the frequency response of bodies has been addressed and explained. It is shown how both types of conclusions are possible depending upon the type of assumptions involved in the solution of the problem or the scope and limitations of experimental observations. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 W Virginia Univ, Dept Mech & Aerosp Engn, Morgantown, WV 26506 USA. US DOE, Fed Energy Technol Ctr, Morgantown, WV 26507 USA. Banaras Hindu Univ, Varanasi, Uttar Pradesh, India. RP Morris, GJ (reprint author), W Virginia Univ, Dept Mech & Aerosp Engn, Morgantown, WV 26506 USA. NR 15 TC 2 Z9 2 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0017-9310 J9 INT J HEAT MASS TRAN JI Int. J. Heat Mass Transf. PD DEC PY 1999 VL 42 IS 23 BP 4287 EP 4297 DI 10.1016/S0017-9310(99)00093-9 PG 11 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA 236ZY UT WOS:000082630200003 ER PT J AU Tilson, JL Minkoff, M Wagner, AK Shepard, R Sutton, P Harrison, RJ Kendall, RA Wong, AT AF Tilson, JL Minkoff, M Wagner, AK Shepard, R Sutton, P Harrison, RJ Kendall, RA Wong, AT TI High performance computational chemistry: Hartree-Fock electronic structure calculations on massively parallel processors SO INTERNATIONAL JOURNAL OF HIGH PERFORMANCE COMPUTING APPLICATIONS LA English DT Article ID CONSISTENT-FIELD CALCULATIONS; DIRECT-SCF; COMPUTERS; INTEGRALS AB The parallel performance of the NWChem version 1.2 alpha parallel direct-SCF code has been characterized on five massively parallel supercomputers (IBM SP, Kendall Square KSR-2, CRAY T3D and T3E, and Intel Touchstone DELTA) using single-point energy calculations on seven molecules of varying size (up to 389 atoms) and composition (first-row atoms, halogens, and transition metals). The authors compare the performance using both replicated-data and distributed-data algorithms and the original McMurchie-Davidson and recently incorporated TEXAS integrals packages. C1 Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. Pacific NW Lab, Environm & Mol Sci Lab, Richland, WA 99352 USA. RP Minkoff, M (reprint author), Argonne Natl Lab, Div Math & Comp Sci, Bldg 221 D239, Argonne, IL 60439 USA. NR 19 TC 8 Z9 8 U1 0 U2 4 PU SAGE PUBLICATIONS INC PI THOUSAND OAKS PA 2455 TELLER RD, THOUSAND OAKS, CA 91320 USA SN 1094-3420 J9 INT J HIGH PERFORM C JI Int. J. High Perform. Comput. Appl. PD WIN PY 1999 VL 13 IS 4 BP 291 EP 302 DI 10.1177/109434209901300401 PG 12 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications; Computer Science, Theory & Methods SC Computer Science GA 247CV UT WOS:000083203800001 ER PT J AU Byrne, GD Hindmarsh, AC AF Byrne, GD Hindmarsh, AC TI PVODE, an ODE solver for parallel computers SO INTERNATIONAL JOURNAL OF HIGH PERFORMANCE COMPUTING APPLICATIONS LA English DT Letter AB PVODE is a general-purpose solver for ordinary differential equation (ODE) systems that implements methods for both stiff and nonstiff systems. The code is designed for single-program multiple-data environments. It is written in ANSI standard C, with a highly modular structure. The version being distributed uses the message-passing interface (MPI) system for communication. In the stiff case, PVODE uses a backward differentiation formula method combined with preconditioned GMRES iteration. Parallelism is achieved by distributing the ODE solution vector into user-specified segments and parallelizing a set of vector kernels accordingly. For PDE-based ODE systems, we provide a module that generates a band block-diagonal preconditioner for use with the GMRES iteration. We also provide a set of interfaces to accommodate Fortran applications. The paper includes a stiff example problem and test results on a Cray-T3D with three different message-passing systems. PVODE is publicly available. C1 Univ Calif Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, Livermore, CA 94551 USA. IIT, Dept Appl Math, Chicago, IL 60616 USA. IIT, Chem & Environm Engn Dept, Chicago, IL 60616 USA. RP Hindmarsh, AC (reprint author), Univ Calif Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, L-561, Livermore, CA 94551 USA. NR 10 TC 41 Z9 41 U1 0 U2 0 PU SAGE PUBLICATIONS INC PI THOUSAND OAKS PA 2455 TELLER RD, THOUSAND OAKS, CA 91320 USA SN 1094-3420 J9 INT J HIGH PERFORM C JI Int. J. High Perform. Comput. Appl. PD WIN PY 1999 VL 13 IS 4 BP 354 EP 365 DI 10.1177/109434209901300405 PG 12 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications; Computer Science, Theory & Methods SC Computer Science GA 247CV UT WOS:000083203800005 ER PT J AU Vosen, SR Keller, JO AF Vosen, SR Keller, JO TI Hybrid energy storage systems for stand-alone electric power systems: optimization of system performance and cost through control strategies SO INTERNATIONAL JOURNAL OF HYDROGEN ENERGY LA English DT Article ID PHOTOVOLTAIC SYSTEMS; HYDROGEN STORAGE AB The development of remote, renewable-based energy is hindered in part by the lack of affordable energy storage. Requiring power-on-demand from an energy system powered by intermittent or seasonal sources may necessitate one-month's energy storage-an expensive proposition using conventional storage technologies. If multiple energy storage devices with complementary performance characteristics are used together, the resulting 'hybrid energystorage system' can dramatically reduce the cost of energy storage over single storage systems. The coupling of conventional storage batteries with emerging hydrogen technologies provides one such hybrid system. Hydrogen energy storage in this context includes an electrolyzer, hydrogen storage tank, and a fuel cell. An additional component that must be considered is the control system that determines when the various components are used. Since the control system has an effect on component sizes and thus system and operating costs, the control algorithm must be carefully considered for any system with energy storage. For this study, a time-dependent model of a stand-alone, solar powered, battery-hydrogen hybrid energy storage system was developed to investigate energy storage options for cases where supply and demand of energy are not well matched daily or seasonally. Simulations were performed for residential use with measured solar fluxes and simulated hourly loads for a site at Yuma, Arizona, USA, a desert climate at 32.7 N latitude. Renewable-based power not needed to satisfy the load is stored for later use. Two hybrid energy-storage algorithms were considered. The first is a conventional 'state-of-charge' control system that uses the current state of the storage system for control. The second control system presumes knowledge of future demand through a feed-forward, neural net or other 'intelligent' control systems. Both algorithms use battery storage to provide much of the daily energy shifting and hydrogen to provide seasonal energy shifting, thus using each storage technology to its best advantage. The cost of storing energy with a hybrid energystorage scheme was found to be much less expensive than either single storage method, with a hybrid system storage costing 48% of the cost of a hydrogen-only system and only 9% of the cost of a conventional, battery-only system. In addition, the neural-net control system is compared to a standard battery state-of-charge control scheme, and it is shown that neural-net control systems better utilize expensive components and result in less expensive electric power than state-of-charge control systems. (C) 1999 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved. C1 Sandia Natl Labs, Livermore, CA 94551 USA. RP Vosen, SR (reprint author), Sandia Natl Labs, Livermore, CA 94551 USA. NR 16 TC 114 Z9 114 U1 3 U2 46 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0360-3199 J9 INT J HYDROGEN ENERG JI Int. J. Hydrog. Energy PD DEC PY 1999 VL 24 IS 12 BP 1139 EP 1156 DI 10.1016/S0360-3199(98)00175-X PG 18 WC Chemistry, Physical; Electrochemistry; Energy & Fuels SC Chemistry; Electrochemistry; Energy & Fuels GA 258RZ UT WOS:000083854100003 ER PT J AU Asay, JR Hall, CA Konrad, CH Trott, WM Chandler, GA Fleming, KJ Holland, KG Chhabildas, LC Mehlhorn, TA Vesey, R Trucano, TG Hauer, A Cauble, R Foord, M AF Asay, JR Hall, CA Konrad, CH Trott, WM Chandler, GA Fleming, KJ Holland, KG Chhabildas, LC Mehlhorn, TA Vesey, R Trucano, TG Hauer, A Cauble, R Foord, M TI Use of Z-pinch sources for high-pressure equation-of-state studies SO INTERNATIONAL JOURNAL OF IMPACT ENGINEERING LA English DT Article; Proceedings Paper CT 6th Symposium on Hypervelocity Impact (HVIS 98) CY NOV 17-19, 1998 CL HUNTSVILLE, AL SP Army Res Lab, Army Res Off, Ernst Mach Inst, European Res Off, Lawrence Livermore Natl Lab, NASA Marshall Space Flight Ctr, Sandia Natl Lab, Univ Alabama, Huntsville, US Army Aviat & Missile Command ID SHOCK-WAVE; TRANSITION AB In this paper, we describe a new technique for using a pulsed power source (Z pinch) to produce planar shock waves for high-pressure equation of state (EOS) studies. Initial EOS experiments indicate that these sources are effective for shock wave studies in samples with diameters of a few millimeters and thicknesses of a fraction of one millimeter, and thus provide the possibility for achieving accuracy in shock and particle velocity measurements of a few percent. We have used the Z pinch source to produce the first in-situ time-resolve particle velocity profiles obtained with pulsed radiation sources in the Mbar regime. Particle velocity profiles obtained with a VISAR interferometer are compared with 1-D numerical simulations performed with a radiation-hydrodynamics code, ALEGRA. Good agreement with experimental results was achieved in the simulations and suggests that the Z pinch source should be a valuable tool for high-pressure EOS studies in thermodynamic regimes important to hypervelocity impact. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Asay, JR (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 17 TC 13 Z9 13 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0734-743X EI 1879-3509 J9 INT J IMPACT ENG JI Int. J. Impact Eng. PD DEC PY 1999 VL 23 IS 1 BP 27 EP 38 DI 10.1016/S0734-743X(99)00059-7 PN 1 PG 12 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA 270EB UT WOS:000084521500006 ER PT J AU Cauble, R Remington, BA Campbell, EM AF Cauble, R Remington, BA Campbell, EM TI Laboratory measurements of materials in extreme conditions: The use of high energy radiation sources for high pressure studies SO INTERNATIONAL JOURNAL OF IMPACT ENGINEERING LA English DT Article; Proceedings Paper CT 6th Symposium on Hypervelocity Impact (HVIS 98) CY NOV 17-19, 1998 CL HUNTSVILLE, ALABAMA SP Army Res Lab, Army Res Off, Ernst Mach Inst, European Res Off, Lawrence Livermore Natl Lab, NASA Marshall Space Flight Ctr, Sandia Natl Lab, Univ Alabama, Huntsville, US Army Aviat & Missile Command ID SHOCK-WAVE EXPERIMENTS; RAYLEIGH-TAYLOR INSTABILITY; MU-M WAVELENGTH; OF-STATE DATA; LIQUID DEUTERIUM; HIGH-DENSITY; MOLECULAR-HYDROGEN; ABSOLUTE EQUATION; FLUID HYDROGEN; SINGLE-MODE AB High energy lasers and pulsed power radiation sources are now being used to study material conditions that have never been explored in the laboratory. Future facilities, like the National Ignition Facility (NIF), designed as a high energy multi-beam laser to achieve thermonuclear ignition of a mm-scale DT-filled target, will offer even more extreme and interesting opportunities. NIF will provide the physics community with a unique tool for the study of high energy density matter at states unreachable by any other laboratory technique. Here we describe how existing lasers and pulsed power devices contribute to investigations of high energy density matter in the areas of material properties and equations of state, augment laboratory shock techniques such as high-speed jets to new regimes, and allow study of extreme conditions found in astrophysical phenomena. We will also describe how such studies are extensible to NIF. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Cauble, R (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 74 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0734-743X J9 INT J IMPACT ENG JI Int. J. Impact Eng. PD DEC PY 1999 VL 23 IS 1 BP 87 EP 99 DI 10.1016/S0734-743X(99)00065-2 PN 1 PG 13 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA 270EB UT WOS:000084521500012 ER PT J AU Chhabildas, LC Konrad, CH Mosher, DA Reinhart, WD Duggins, BD Trucano, TG Summers, RM Peery, JS AF Chhabildas, LC Konrad, CH Mosher, DA Reinhart, WD Duggins, BD Trucano, TG Summers, RM Peery, JS TI A methodology to validate 3D arbitrary Lagrangian Eulerian codes with applications to ALEGRA SO INTERNATIONAL JOURNAL OF IMPACT ENGINEERING LA English DT Article; Proceedings Paper CT 6th Symposium on Hypervelocity Impact (HVIS 98) CY NOV 17-19, 1998 CL HUNTSVILLE, ALABAMA SP Army Res Lab, Army Res Off, Ernst Mach Inst, European Res Off, Lawrence Livermore Natl Lab, NASA Marshall Space Flight Ctr, Sandia Natl Lab, Univ Alabama, Huntsville, US Army Aviat & Missile Command AB In this study we provided an experimental test bed for validating features of the Arbitrary Lagrangian Eulerian Grid for Research Applications (ALEGRA) code over a broad range of strain rates with overlapping diagnostics that encompass the multiple responses. A unique feature of the ALEGRA code is that it allows simultaneous computational treatment, within one code, of a wide range of strain-rates varying from hydrodynamic to structural conditions. This range encompasses strain rates characteristic of shock-wave propagation (10(7)/s) and those characteristics of structural response (10(2)/s). Most previous code validation experimental studies, however, have been restricted to simulating or investigating a single strain-rate regime. What is new and different in this investigation is that we have performed well-controlled and well-instrumented experiments, which capture features relevant to both hydrodynamic and structural response in a single experiment. Aluminum was chosen for use in this study because it is a well-characterized material. The current experiments span strain rate regimes of over 10(7)/s to less than 10(2)/s in a single experiment. The input conditions were extremely well defined. Velocity interferometers were used to record the high strain-rate response, while low strain rate data were collected using strain gauges. Although the current tests were conducted at a nominal velocity of similar to 1.5 km/s, it is the test methodology that is being emphasized herein. Results of a three-dimensional experiment are also presented. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Sandia Natl Labs, Shock Phys Applicat Dept, Albuquerque, NM 87185 USA. RP Chhabildas, LC (reprint author), Sandia Natl Labs, Shock Phys Applicat Dept, POB 5800, Albuquerque, NM 87185 USA. NR 9 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0734-743X J9 INT J IMPACT ENG JI Int. J. Impact Eng. PD DEC PY 1999 VL 23 IS 1 BP 101 EP 112 DI 10.1016/S0734-743X(99)00066-4 PN 1 PG 12 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA 270EB UT WOS:000084521500013 ER PT J AU Crawford, DA Schultz, PH AF Crawford, DA Schultz, PH TI Electromagnetic properties of impact-generated plasma, vapor and debris SO INTERNATIONAL JOURNAL OF IMPACT ENGINEERING LA English DT Article; Proceedings Paper CT 6th Symposium on Hypervelocity Impact (HVIS 98) CY NOV 17-19, 1998 CL HUNTSVILLE, ALABAMA SP Army Res Lab, Army Res Off, Ernst Mach Inst, European Res Off, Lawrence Livermore Natl Lab, NASA Marshall Space Flight Ctr, Sandia Natl Lab, Univ Alabama, Huntsville, US Army Aviat & Missile Command ID MAGNETIC-FIELDS AB Plasma, vapor and debris associated with an impact or explosive event have been demonstrated in the laboratory to produce radiofrequency and optical electromagnetic emissions that can be diagnostic of the event. Such effects could potentially interfere with communications or remote sensing equipment if an impact occurred, for example, on a satellite. More seriously, impact generated plasma could end the life of a satellite by mechanisms that are not well understood and not normally taken into account in satellite design. For example, arc/discharge phenomena resulting from highly conductive plasma acting as a current path across normally shielded circuits may have contributed to the loss of the Olympus experimental communications satellite on August 11, 1993. The possibility of significant storm activity during the Leonid meteor showers of November 1998, 1999 and 2000 (impact velocity, 72 km/s) has heightened awareness of potential vulnerabilities from hypervelocity electromagnetic effects to orbital assets. The concern is justified. The amount of plasma, electrostatic charge and the magnitude of the resulting currents and electric fields scale nearly as the cube of the impact velocity (proportional to(v)(2,6)). Even for microscopic Leonid impacts, the amount of plasma approaches levels that could be dangerous to spacecraft electronics. The degree of charge separation that occurs during hypervelocity impacts scales linearly with impactor mass. The resulting magnetic fields increase linearly with impactor radius and could play a significant role in our understanding of the paleomagnetism of planetary surfaces. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Sandia Natl Labs, Dept Computat Phys & Mech 9232, Albuquerque, NM 87185 USA. Brown Univ, Dept Geol Sci, Providence, RI 02912 USA. RP Crawford, DA (reprint author), Sandia Natl Labs, Dept Computat Phys & Mech 9232, POB 5800, Albuquerque, NM 87185 USA. NR 10 TC 58 Z9 59 U1 0 U2 8 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0734-743X J9 INT J IMPACT ENG JI Int. J. Impact Eng. PD DEC PY 1999 VL 23 IS 1 BP 169 EP 180 DI 10.1016/S0734-743X(99)00070-6 PN 1 PG 12 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA 270EB UT WOS:000084521500017 ER PT J AU Furnish, MD Chhabildas, LC Reinhart, WD AF Furnish, MD Chhabildas, LC Reinhart, WD TI Time-resolved particle velocity measurements at impact velocities of 10 km/s SO INTERNATIONAL JOURNAL OF IMPACT ENGINEERING LA English DT Article; Proceedings Paper CT 6th Symposium on Hypervelocity Impact (HVIS 98) CY NOV 17-19, 1998 CL HUNTSVILLE, ALABAMA SP Army Res Lab, Army Res Off, Ernst Mach Inst, European Res Off, Lawrence Livermore Natl Lab, NASA Marshall Space Flight Ctr, Sandia Natl Lab, Univ Alabama, Huntsville, US Army Aviat & Missile Command ID HYPERVELOCITY AB Hypervelocity launch capabilities (9 - 16 km/s) with macroscopic plates have become available in recent years. It is now feasible to conduct instrumented plane-wave tests using this capability. Successfully conducting such tests requires a planar launch and impact at hypervelocities, appropriate triggering for recording systems, and time-resolved measurements of motion or stress at a particular point or set of points within the target or projectile during impact. We have conducted the first time-resolved wave-profile experiments using velocity interferometric techniques at impact velocities of 10 km/s. These measurements show that aluminum continues to exhibit normal release behavior to 161 cpa shock pressure, with complete loss of strength of the shocked state. These experiments have allowed a determination of shockwave window transparency in conditions produced by a hypervelocity impact. In particular, lithium fluoride appears to lose transparency at a shock stress of 200 GPa; this appears to be the upper limit for conventional wave profile measurements using velocity interferometric techniques. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Furnish, MD (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 23 TC 39 Z9 47 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0734-743X J9 INT J IMPACT ENG JI Int. J. Impact Eng. PD DEC PY 1999 VL 23 IS 1 BP 261 EP 270 DI 10.1016/S0734-743X(99)00078-0 PN 1 PG 10 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA 270EB UT WOS:000084521500025 ER PT J AU Hall, CA Chhabildas, LC Reinhart, WD AF Hall, CA Chhabildas, LC Reinhart, WD TI Shock Hugoniot and release in concrete with different aggregate sizes from 3 to 23 GPa SO INTERNATIONAL JOURNAL OF IMPACT ENGINEERING LA English DT Article; Proceedings Paper CT 6th Symposium on Hypervelocity Impact (HVIS 98) CY NOV 17-19, 1998 CL HUNTSVILLE, ALABAMA SP Army Res Lab, Army Res Off, Ernst Mach Inst, European Res Off, Lawrence Livermore Natl Lab, NASA Marshall Space Flight Ctr, Sandia Natl Lab, Univ Alabama, Huntsville, US Army Aviat & Missile Command AB A series of controlled impact experiments has been performed to determine the shock loading and release behavior of two types of concrete, differentiated by aggregate size, but with average densities varying by less than 2 percent. Hugoniot stress and subsequent release data was collected over a range of approximately 3 to 25 GPa using a plate reverberation technique in combination with velocity interferometry. The results of the current data are compared to those obtained in previous studies on concrete with a different aggregate size but similar density. Results indicate that the average loading and release behavior are comparable for the three types of concrete discussed in this paper. Residual strain is also indicated from these measurements. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Hall, CA (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 13 TC 9 Z9 12 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0734-743X J9 INT J IMPACT ENG JI Int. J. Impact Eng. PD DEC PY 1999 VL 23 IS 1 BP 341 EP 351 DI 10.1016/S0734-743X(99)00085-8 PN 1 PG 11 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA 270EB UT WOS:000084521500032 ER PT J AU Kalantar, DH Remington, BA Chandler, EA Colvin, JD Gold, DM Mikaelian, KO Weber, SV Wiley, LG Wark, JS Hauer, AA Meyers, MA AF Kalantar, DH Remington, BA Chandler, EA Colvin, JD Gold, DM Mikaelian, KO Weber, SV Wiley, LG Wark, JS Hauer, AA Meyers, MA TI High pressure solid state experiments on the Nova laser SO INTERNATIONAL JOURNAL OF IMPACT ENGINEERING LA English DT Article; Proceedings Paper CT 6th Symposium on Hypervelocity Impact (HVIS 98) CY NOV 17-19, 1998 CL HUNTSVILLE, ALABAMA SP Army Res Lab, Army Res Off, Ernst Mach Inst, European Res Off, Lawrence Livermore Natl Lab, NASA Marshall Space Flight Ctr, Sandia Natl Lab, Univ Alabama, Huntsville, US Army Aviat & Missile Command AB An x-ray drive has been developed to shock compress metal foils in the solid state in order to study the material strength under high compression. The drive has been characterized and hydrodynamics experiments designed to study growth of the Rayleigh-Taylor (RT) instability in Cu foils at 3 Mbar peak pressures have been started. Pre-imposed modulations with an initial wavelength of 20-50 mu m, and amplitudes of 1.0-2.5 mu m show growth consistent with simulations. In this parameter regime, the fluid and solid states are expected to behave similarly for Cu. An analytic stability analysis is used to motivate an experimental design with an Al foil where the effects of material strength on the RT growth are significantly enhanced. Improved x-ray drive design will allow the material to stay solid under compression throughout the experiment, and dynamic diffraction techniques are being developed to verify the compressed state. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Oxford, Dept Phys, Clarendon Lab, Oxford OX1 3PU, England. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Calif San Diego, La Jolla, CA 92043 USA. RP Kalantar, DH (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RI Meyers, Marc/A-2970-2016 OI Meyers, Marc/0000-0003-1698-5396 NR 19 TC 4 Z9 5 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0734-743X J9 INT J IMPACT ENG JI Int. J. Impact Eng. PD DEC PY 1999 VL 23 IS 1 BP 409 EP 419 DI 10.1016/S0734-743X(99)00091-3 PN 1 PG 11 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA 270EB UT WOS:000084521500038 ER PT J AU Kanel, GI Asay, JR Baumung, K Bluhm, H Chhabildas, LC Fortov, VE Goel, B Hoppe, P Mehlhorn, T Razorenov, SV Rusch, D Utkin, AV AF Kanel, GI Asay, JR Baumung, K Bluhm, H Chhabildas, LC Fortov, VE Goel, B Hoppe, P Mehlhorn, T Razorenov, SV Rusch, D Utkin, AV TI Applications of the ion beam technique for investigations of hypervelocity impacts SO INTERNATIONAL JOURNAL OF IMPACT ENGINEERING LA English DT Article; Proceedings Paper CT 6th Symposium on Hypervelocity Impact (HVIS 98) CY NOV 17-19, 1998 CL HUNTSVILLE, ALABAMA SP Army Res Lab, Army Res Off, Ernst Mach Inst, European Res Off, Lawrence Livermore Natl Lab, NASA Marshall Space Flight Ctr, Sandia Natl Lab, Univ Alabama, Huntsville, US Army Aviat & Missile Command ID DIAGNOSTICS; PRESSURES; EQUATION; TARGETS; RELEASE; STATE AB In the presentation we report on experiments at the Karlsruhe Light Ion Facility KALIF employing high-resolution laser-Doppler velocimetry. The schemes of possible EOS experiments using interferometry and the dynamics and the limiting factors of the ablative hypervelocity launching are discussed as well as advantages of the ion beam technique for investigations in the field of hypervelocity impacts and equations of state. So far, we have accelerated aluminum foils of 10 to 30 mu m thickness to velocities beyond 12 km/s. Besides the beam power, the limiting factors for the launching are melting of the accelerated flyer plate as a result of shock-wave heating and the heat transfer from the energy deposition zone. The experiments considered include the Hugoniot measurements and measurements at unloading of shock-compressed state down to the vaporization region. Parameters of shock waves that cause melting of aluminum, copper, molybdenum and titanium in release have been measured with a pulse proton beam on KALIF. A way of measurements in the vaporization region has been tested with explosive facilities. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 High Energy Dens Res Ctr, Moscow 127412, Russia. Sandia Natl Labs, Target & Pinch Theory Dept Z, Albuquerque, NM 87185 USA. Forschungszentrum Karlsruhe, D-76021 Karlsruhe, Germany. Inst Chem Phys Res, Chernogolovka 142432, Russia. RP Kanel, GI (reprint author), High Energy Dens Res Ctr, Izhorskaya 13-19, Moscow 127412, Russia. RI Kanel, Gennady/K-1657-2013; Razorenov, Sergei/O-6450-2014 NR 24 TC 6 Z9 6 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0734-743X J9 INT J IMPACT ENG JI Int. J. Impact Eng. PD DEC PY 1999 VL 23 IS 1 BP 421 EP 430 DI 10.1016/S0734-743X(99)00092-5 PN 1 PG 10 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA 270EB UT WOS:000084521500039 ER PT J AU Piekutowski, AJ Forrestal, MJ Poormon, KL Warren, TL AF Piekutowski, AJ Forrestal, MJ Poormon, KL Warren, TL TI Penetration of 6061-T6511 aluminum targets by ogive-nose steel projectiles with striking velocities between 0.5 and 3.0 km/s SO INTERNATIONAL JOURNAL OF IMPACT ENGINEERING LA English DT Article; Proceedings Paper CT 6th Symposium on Hypervelocity Impact (HVIS 98) CY NOV 17-19, 1998 CL HUNTSVILLE, ALABAMA SP Army Res Lab, Army Res Off, Ernst Mach Inst, European Res Off, Lawrence Livermore Natl Lab, NASA Marshall Space Flight Ctr, Sandia Natl Lab, Univ Alabama, Huntsville, US Army Aviat & Missile Command ID LONG RODS AB We performed a series of depth-of-penetration experiments using 7.11-mm-diameter, 71.12-mm-long, ogive-nose steel projectiles and 254-mm-diameter, 6061-T6511 aluminum targets. The projectiles were made from vacuum-are remelted (VAR) 4340 steel (R-C 38) and AerMet 100 steel (R-C 53), had a nominal mass of 0.021 kg, and were launched using a powder gun or a two-stage, light gas gun to striking velocities between 0.5 and 3.0 km/s. Since the tensile yield strength of AerMet 100 (R-C 53) steel is about 1.5 times greater than VAR 4340 (R-C 38) steel, we were able to demonstrate the effect of projectile strength on ballistic performance. Post-test radiographs of the targets showed three different regions of penetrator response as the striking velocity increased: (1) the projectiles remained rigid and visibly undeformed; (2) the projectiles deformed during penetration without nose erosion, deviated from the target centerline, and exited the side of the target or turned severely within the target; and (3) the projectiles eroded during penetration and lost mass. To show the effect of projectile strength, we present depth-of-penetration data as a function of striking velocity for both types of steel projectiles at striking velocities ranging from 0.5 and 3.0 km/s. In addition, we show good agreement between the rigid-projectile penetration data and a cavity-expansion model. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Dayton, Res Inst, Dayton, OH 45469 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Piekutowski, AJ (reprint author), Univ Dayton, Res Inst, 300 Coll Pk Ave, Dayton, OH 45469 USA. NR 11 TC 62 Z9 71 U1 0 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0734-743X J9 INT J IMPACT ENG JI Int. J. Impact Eng. PD DEC PY 1999 VL 23 IS 1 BP 723 EP 734 DI 10.1016/S0734-743X(99)00117-7 PN 2 PG 12 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA 270ED UT WOS:000084521700020 ER PT J AU Reaugh, JE Holt, AC Wilkins, ML Cunningham, BJ Hord, BL Kusubov, AS AF Reaugh, JE Holt, AC Wilkins, ML Cunningham, BJ Hord, BL Kusubov, AS TI Impact studies of five ceramic materials and Pyrex SO INTERNATIONAL JOURNAL OF IMPACT ENGINEERING LA English DT Article; Proceedings Paper CT 6th Symposium on Hypervelocity Impact (HVIS 98) CY NOV 17-19, 1998 CL HUNTSVILLE, ALABAMA SP Army Res Lab, Army Res Off, Ernst Mach Inst, European Res Off, Lawrence Livermore Natl Lab, NASA Marshall Space Flight Ctr, Sandia Natl Lab, Univ Alabama, Huntsville, US Army Aviat & Missile Command AB We measured the ballistic performance of five ceramic materials (alumina, silicon carbide, boron carbide, aluminum nitride, and titanium diboride) and Pyrex, when they are backed by thick steel plates. The projectile for all tests was a right-circular cylinder of tungsten sinter-alloy W2 with length 25.4 mm and diameter 6.35 mm, fired at velocities from 1.35 to 2.65 km/s. For this threat we determined the minimum areal density of each material that is needed to keep the projectile from penetrating the backup steel. For all of the facing materials studied here, this performance measure increases approximately linearly with projectile velocity. However, the rate of increase is significantly lower for aluminum nitride than for the other materials studied. Indeed, aluminum nitride is a poor performer at the lowest velocity tested, but is clearly the best at the highest velocity. Our computer simulations show the significant influence of the backing material on ceramic performance, manifested by a transition region extending two projectile diameters upstream from the material interface. Experiments with multiple material layers show that this influence also manifests itself through a significant dependence of ballistic performance on the ordering of the material layers. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Reaugh, JE (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NR 16 TC 21 Z9 23 U1 1 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0734-743X J9 INT J IMPACT ENG JI Int. J. Impact Eng. PD DEC PY 1999 VL 23 IS 1 BP 771 EP 782 DI 10.1016/S0734-743X(99)00121-9 PN 2 PG 12 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA 270ED UT WOS:000084521700024 ER PT J AU Tokheim, RE Curran, DR Seaman, L Cooper, T Anderson, AT Burnham, AK Scott, JM Latkowski, J Schirmann, D AF Tokheim, RE Curran, DR Seaman, L Cooper, T Anderson, AT Burnham, AK Scott, JM Latkowski, J Schirmann, D TI Hypervelocity shrapnel damage assessment in NIF target chamber SO INTERNATIONAL JOURNAL OF IMPACT ENGINEERING LA English DT Article; Proceedings Paper CT 6th Symposium on Hypervelocity Impact (HVIS 98) CY NOV 17-19, 1998 CL HUNTSVILLE, ALABAMA SP Army Res Lab, Army Res Off, Ernst Mach Inst, European Res Off, Lawrence Livermore Natl Lab, NASA Marshall Space Flight Ctr, Sandia Natl Lab, Univ Alabama, Huntsville, US Army Aviat & Missile Command AB In the National Ignition Facility (NIF) target chamber, hypervelocity shrapnel may be produced as the result of neutron and x-ray deposition in target and diagnostic support rods, photon shields, and other objects in the chamber. This shrapnel may pose a hazard for optics debris shields and chamber wall materials. This paper presents the results of a computational and experimental effort to develop a predictive methodology for assessing hypervelocity shrapnel damage. The methodology begins with computations of the size and velocity distributions for the shrapnel, which is typically computed to consist of sizes ranging from submicron to a few hundred micrometers and to span a velocity range from a few hundred m/s to tens of km/s. Damage algorithms were developed based on prior dimensional analyses and hydrocode cratering computations, hypervelocity data from the hypervelocity impact community, and laboratory impact data at a few hundred m/s. The predictions of the algorithms agreed well with the damage observed in the Lawrence Livermore National Laboratory NOVA and the French Commissariat a l'Energie Atomique PHEBUS laser facilities. The algorithms were then used to calculate damage maps in the NIF chamber for typical source conditions. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 SRI Int, Poulter Lab, Menlo Park, CA 94025 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. CEA, Paris, France. RP Tokheim, RE (reprint author), SRI Int, Poulter Lab, 333 Ravenswood Ave, Menlo Park, CA 94025 USA. NR 9 TC 5 Z9 5 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0734-743X J9 INT J IMPACT ENG JI Int. J. Impact Eng. PD DEC PY 1999 VL 23 IS 1 BP 933 EP 944 DI 10.1016/S0734-743X(99)00136-0 PN 2 PG 12 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA 270ED UT WOS:000084521700038 ER PT J AU Van Oers, WTH AF Van Oers, WTH TI Constraints on a parity-conserving/time-reversal-non-conserving interaction SO INTERNATIONAL JOURNAL OF MODERN PHYSICS E-NUCLEAR PHYSICS LA English DT Review ID CHARGE-SYMMETRY-BREAKING; NUCLEON-NUCLEON SYSTEM; NP ELASTIC-SCATTERING; INVARIANCE; VIOLATION; TESTS AB Time-reversal-invariance non-conservation has for the first time been unequivocally demonstrated in a direct measurement at CPLEAR. One then can ask the question: What about tests of time-reversal-invariance in systems other than the kaon system? Tests of time-reversal-invariance can be distinguished as belonging to two classes: the first one deals with parity violating (P-odd)/time-reversal-invariance-odd (T-odd) interactions, while the second one deals with P-even/T-odd interactions (assuming CPT conservation this implies C-conjugation non-conservation). Limits on a P-odd/T-odd interaction follow from measurements of the electric dipole moment of the neutron (with a present upper limit of 6 x 10(-26) e.cm [95% C.L.]). It provides a limit on a P-odd/T-odd pion-nucleon coupling constant which is less than 10(-4) times the weak interaction strength. Experimental limits on a P-even/T-odd interaction are much less stringent. Following the standard approach of describing the nucleon-nucleon interaction in terms of meson exchanges it can be shown that only charged rho-meson exchange and A(1)-meson exchange can lead to a P-even/T-odd interaction. The better constraints stem from measurements of the electric dipole moment of the neutron and from measurements of charge-symmetry breaking in neutron-proton elastic scattering. The latter experiments were executed at TRIUMF (497 and 347 MeV) and at IUCF (183 MeV). Weak decay experiments may provide limits which will possibly be comparable. All other experiments, like gamma decay experiments, detailed balance experiments, polarization-analyzing power difference determinations, and five-fold correlation experiments with polarized incident nucleons and aligned nuclear targets, have been shown to be at least an order of magnitude less sensitive. The question then emerges: is there room for further experimentation? C1 Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. Univ Manitoba, Dept Phys, Winnipeg, MB R3T 2N2, Canada. TRIUMF, Vancouver, BC V6T 2A3, Canada. RP Van Oers, WTH (reprint author), Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. NR 31 TC 1 Z9 1 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0218-3013 J9 INT J MOD PHYS E JI Int. J. Mod. Phys. E-Nucl. Phys. PD DEC PY 1999 VL 8 IS 6 BP 513 EP 526 DI 10.1142/S0218301399000355 PG 14 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 302JC UT WOS:000086361100002 ER PT J AU Dorn, O Bertete-Aguirre, H Berryman, JG Papanicolaou, GC AF Dorn, O Bertete-Aguirre, H Berryman, JG Papanicolaou, GC TI A nonlinear inversion method for 3D electromagnetic imaging using adjoint fields SO INVERSE PROBLEMS LA English DT Article ID GROUND-PENETRATING RADAR; BOUNDARY-VALUE PROBLEM; FREQUENCY-DOMAIN; TOMOGRAPHY; SCATTERING; WAVES AB Electromagnetic imaging is modelled as an inverse problem for the 3D system of Maxwell's equations of which the isotropic conductivity distribution in the domain of interest has to be reconstructed. The main application we have in mind is the monitoring of conducting contaminant plumes out of surface and borehole electromagnetic imaging data. The essential feature of the method developed here is the use of adjoint fields for the reconstruction task, combined with a splitting of the data into smaller groups which define subproblems of the inversion problem. The method works iteratively, and can be considered as a nonlinear generalization of the algebraic reconstruction technique in x-ray tomography. Starting out from some initial guess for the conductivity distribution, an update for this guess is computed by solving one forward and one adjoint problem of the 3D Maxwell system at a time. Numerical experiments are performed for a layered background medium in which one or two localized (3D) inclusions are immersed. These have to be monitored out of surface to borehole and cross-borehole electromagnetic data. We show that the algorithm is able to recover a single inclusion in the earth which has high contrast to the background, and to distinguish between two separated inclusions in the earth given certain borehole geometries. C1 Stanford Univ, Dept Math, Stanford, CA 94305 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Dorn, O (reprint author), Stanford Univ, Dept Math, Stanford, CA 94305 USA. RI Berryman, James/A-9712-2008 NR 35 TC 83 Z9 84 U1 1 U2 5 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0266-5611 J9 INVERSE PROBL JI Inverse Probl. PD DEC PY 1999 VL 15 IS 6 BP 1523 EP 1558 DI 10.1088/0266-5611/15/6/309 PG 36 WC Mathematics, Applied; Physics, Mathematical SC Mathematics; Physics GA 265ZX UT WOS:000084277100010 ER PT J AU Vasco, DW AF Vasco, DW TI Intersections, ideals, and inversion SO INVERSE PROBLEMS LA English DT Article ID POLYNOMIAL SYSTEMS; HOMOTOPIES AB Techniques from computational algebra provide a framework for treating large classes of inverse problems. In particular, the discretization of many integral equations and partial differential equations with undetermined coefficients leads to systems of polynomial equations. The structure of the solution sets of such equations may be examined using algebraic techniques. For example, the existence and dimensionality of the solution set may be determined. Furthermore, it is possible to bound the total number of solutions. The approach is illustrated by a numerical application to the inverse problem associated with the Helmholtz equation. The techniques are also applied to a set of magnetotelluric observations gathered at Battle Mountain, Nevada. Based upon 19 distinct inversions for vertical structure, an image of subsurface conductivity variations is constructed. The existence of solutions to the inverse problem is demonstrated and the number of solutions associated with each inversion is found to be finite, bounded from above at 73. The set of best fitting solutions contains features which are interpretable in terms of the local geology. In particular, a resistive body, associated with a granitic-porphyry intrusive, is imaged. In addition, conductive anomalies can be correlated with the intrusives metamorphic aureole and adjacent Tertiary gravels. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Computat Seismol, Berkeley, CA 94720 USA. RP Vasco, DW (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Computat Seismol, Berkeley, CA 94720 USA. RI Vasco, Donald/I-3167-2016 OI Vasco, Donald/0000-0003-1210-8628 NR 50 TC 2 Z9 2 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0266-5611 J9 INVERSE PROBL JI Inverse Probl. PD DEC PY 1999 VL 15 IS 6 BP 1573 EP 1602 DI 10.1088/0266-5611/15/6/311 PG 30 WC Mathematics, Applied; Physics, Mathematical SC Mathematics; Physics GA 265ZX UT WOS:000084277100012 ER PT J AU Matsuzawa, NN Oizumi, H Mori, S Irie, S Shirayone, S Yano, E Okazaki, S Ishitani, A Dixon, DA AF Matsuzawa, NN Oizumi, H Mori, S Irie, S Shirayone, S Yano, E Okazaki, S Ishitani, A Dixon, DA TI Theoretical calculation of photoabsorption of various polymers in an extreme ultraviolet region SO JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS LA English DT Article; Proceedings Paper CT 12th International Microprocesses and Nanotechnology Conference (MNC 99) CY JUL 06-08, 1999 CL YOKOHAMA, JAPAN SP Japan Soc Appl Phys, IEEE Electron Device Soc, Amer Vacuum Soc, Assoc Super Adv Electr Technologies, Inst Electr Engineers Japan, Inst Electr Informat & Commun Engineers, Japanese Soc Electron Microscope, Japanese Soc Synchrotron radiat res, Surface Sci Soc Japan, Vacuum Soc Japan, Yokohama City DE linear absorption coefficient; density; 13 nm; EUV lithography ID RAY AB We have calculated the linear absorption coefficients of various resist polymers using the mass absorption coefficients at 13 nm and the density obtained from the graph-theoretical treatment derived by Bicerano. The values indicate that the transmittance at 13 nm of conventional resists used in 193-nm, 248-nm and 365-nm lithography is about 30% when the thickness is 3000 Angstrom and 60-70% when it is 1000 Angstrom. This shows that conventional resists are suitable for an EUVL (extreme ultraviolet lithography) thin-layer resist (TLR) process using a hard-mask layer, but their large photoabsorption makes them unsuitable for a single-layer resist (SLR) process. To design polymers that are suitable for an SLR process, we further calculated the absorption of about 150 polymers. The results suggest that the introduction of aromatic groups into a polymer not only reduces the absorption at 13 nm but also increases the etching resistance. C1 Assoc Super Adv Elect Technol, Atsugi Res Ctr, NTT, Atsugi R&D Ctr, Atsugi, Kanagawa 2430198, Japan. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Sony Corp, Frontier Sci Labs, Yokohama, Kanagawa, Japan. RP Matsuzawa, NN (reprint author), Assoc Super Adv Elect Technol, Atsugi Res Ctr, NTT, Atsugi R&D Ctr, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 2430198, Japan. NR 17 TC 41 Z9 41 U1 3 U2 9 PU INST PURE APPLIED PHYSICS PI MINATO-KU TOKYO PA DAINI TOYOKAIJI BLDG, 4-24-8 SHINBASHI, MINATO-KU TOKYO, 105-004, JAPAN SN 0021-4922 J9 JPN J APPL PHYS 1 JI Jpn. J. Appl. Phys. Part 1 - Regul. Pap. Short Notes Rev. Pap. PD DEC PY 1999 VL 38 IS 12B BP 7109 EP 7113 DI 10.1143/JJAP.38.7109 PG 5 WC Physics, Applied SC Physics GA 388UQ UT WOS:000166201800031 ER PT J AU Aranson, I Nattermann, T Scheidl, S Vinokur, V AF Aranson, I Nattermann, T Scheidl, S Vinokur, V TI Depinning and stability of driven phases in a dirty environment SO JOURNAL DE PHYSIQUE IV LA English DT Meeting Abstract ID DYNAMICS C1 Univ Cologne, Inst Theoret Phys, D-50937 Cologne, Germany. Argonne Natl Lab, Argonne, IL 60439 USA. RI Aranson, Igor/I-4060-2013 NR 4 TC 0 Z9 0 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 1155-4339 J9 J PHYS IV JI J. Phys. IV PD DEC PY 1999 VL 9 IS P10 BP 63 EP 63 DI 10.1051/jp4:19991015 PG 1 WC Physics, Multidisciplinary SC Physics GA 278YT UT WOS:000085017100016 ER PT J AU Vinokur, VM AF Vinokur, VM TI Driven periodic structures in random environment SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT International Workshop on Electronic Crystals (ECRYS-99) CY MAY 31-JUN 05, 1999 CL LA COLLE-SUR-LOUP, FRANCE ID MOVING GLASS PHASE; FLUX-LINE-LATTICE; DYNAMICS; MEDIA AB We consider a lattice driven in a random environment and analyse its large-scale dynamics in the context of the driven vortex configuration. Using a perturbative coarse-graing procedure, we derive explicitely renormalized equation of motion, including Kardar-Parizi-Zhang nonlinearities and dynamic strain terms. From the generalized Lindemann criterion for the fluctuations of the neighboring sites the temperature shift of the dynamic melting is found to scale proportional to the strength of the disorder and inversly proportional to large driving forces. The presence of dislocations leads to a characteristic anisotropic distortion of the Vortex density that is controlled by a Kardar-Parisi-Zhang nonlinlearity in the coarse-grained equation of motion. This nonlinearity also implies a screening of the interaction between dislocations and thereby an instability of the vortex lattice to the proliferation of free dislocations. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Vinokur, VM (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 15 TC 0 Z9 0 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 1155-4339 J9 J PHYS IV JI J. Phys. IV PD DEC PY 1999 VL 9 IS P10 BP 85 EP 87 DI 10.1051/jp4:19991022 PG 3 WC Physics, Multidisciplinary SC Physics GA 278YT UT WOS:000085017100023 ER PT J AU Scheidl, S Rosenow, B AF Scheidl, S Rosenow, B TI Chern-Simons theory for electrons in high Landau levels SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT International Workshop on Electronic Crystals (ECRYS-99) CY MAY 31-JUN 05, 1999 CL LA COLLE-SUR-LOUP, FRANCE ID WEAK MAGNETIC-FIELD; LIQUID AB We develop a Chern-Simons-Landau-Ginzburg theory to describe a two-dimensional electron gas in intermediate magnetic fields. From this theory the formation of a charge-density wave (CDW) state at half filling of high Landau-Levels is derived. The CDW consists of incompressible stripes with diamagnetic edge currents. C1 Univ Cologne, Inst Theoret Phys, D-50937 Cologne, Germany. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Scheidl, S (reprint author), Univ Cologne, Inst Theoret Phys, Zulpichar Str 77, D-50937 Cologne, Germany. NR 10 TC 0 Z9 0 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 1155-4339 J9 J PHYS IV JI J. Phys. IV PD DEC PY 1999 VL 9 IS P10 BP 223 EP 225 DI 10.1051/jp4:19991056 PG 3 WC Physics, Multidisciplinary SC Physics GA 278YT UT WOS:000085017100057 ER PT J AU Tessema, GX Gamble, BK Kuh, J Skove, MJ Lacerda, AH Bennett, M AF Tessema, GX Gamble, BK Kuh, J Skove, MJ Lacerda, AH Bennett, M TI NbSe3: Fermi surface and magnetoresistance under uniaxial stress SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT International Workshop on Electronic Crystals (ECRYS-99) CY MAY 31-JUN 05, 1999 CL LA COLLE-SUR-LOUP, FRANCE ID FIELDS AB The Fermi surface of NbSe3 below the two CDW transitions is still not very dear. Large magnetoresistance and giant quantum oscillations have been seen at low temperature below the second CDW transition. The SdH oscillations are attributed to one or several small pieces of electron or hole pockets spared by the two CDW transitions at 145 and 59 K. In a previous low field study (mu(0)H<8T) of the transverse magnetoresistance (H in the (b,c) plane) we have shown that the extremal area of one of these pockets decreases linearly with strain, epsilon, vanishing at epsilon = 2.5%. Here we extend our study into the high magnetic field regime (pulsed 60 T) and investigate the effect of uniaxial stress on the magnetoresistance (I//H). Our high field study is consistent with the fermiology study and shows that uniaxial stress leads to the obliteration of a small closed pocket. Above 1% strain the magnetoresistance is linear with H with no sign of saturation. C1 Clemson Univ, Clemson, SC 29631 USA. Univ Calif Los Alamos Natl Lab, NHMFL, Los Alamos, NM 87544 USA. RP Tessema, GX (reprint author), Clemson Univ, Clemson, SC 29631 USA. NR 4 TC 0 Z9 0 U1 1 U2 4 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 DEC PY 1999 VL 9 IS P10 BP 255 EP 257 DI 10.1051/jp4:19991064 PG 3 WC Physics, Multidisciplinary SC Physics GA 278YT UT WOS:000085017100065 ER PT J AU Gordon, SH Jones, RW McClelland, JF Wicklow, DT Greene, RV AF Gordon, SH Jones, RW McClelland, JF Wicklow, DT Greene, RV TI Transient infrared spectroscopy for detection of toxigenic fungus in corn: Potential for on-line evaluation SO JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY LA English DT Article DE Aspergillus flavus; aflatoxin; fungi; corn; transient infrared spectroscopy; FTIR-photoacoustic spectroscopy ID GREENISH-YELLOW FLUORESCENCE; EMISSION SPECTROSCOPY; FUSARIUM-MONILIFORME; ASPERGILLUS-FLAVUS; NATURAL OCCURRENCE; AFLATOXIN; FUMONISIN-B1 AB An urgent need for rapid sensors to detect contamination of food grains by toxigenic fungi such as Aspergillus flavus prompted research and development of Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) as a highly sensitive probe for fungi growing on the surfaces of individual corn kernels. However, the photoacoustic technique has limited potential for screening bulk corn because currently available photoacoustic detectors can accommodate only a single intact kernel at a time. Transient infrared spectroscopy (TIRS), on the other hand, is a promising new technique that can acquire analytically useful infrared spectra from a moving mass of solid materials. Therefore, the potential of TIRS for on-line, noncontact detection of A. flavus contamination in a moving bed of corn kernels was explored. Early test results based on visual inspection of TIRS spectral differences predict an 85% or 95% success rate in distinguishing healthy corn from grain infected with A. flavus. Four unique infrared spectral features which identified infected corn in FTIR-PAS were also found to be diagnostic in TIRS. Although the technology is still in its infancy, the preliminary results indicate that TIRS is a potentially effective screening method for bulk quantities of corn grain. C1 ARS, USDA, Natl Ctr Agr Utilizat Res, Peoria, IL 61604 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Gordon, SH (reprint author), ARS, USDA, Natl Ctr Agr Utilizat Res, 1815 N Univ St, Peoria, IL 61604 USA. EM gordonsh@mail.ncaur.usda.gov NR 30 TC 35 Z9 35 U1 1 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0021-8561 J9 J AGR FOOD CHEM JI J. Agric. Food Chem. PD DEC PY 1999 VL 47 IS 12 BP 5267 EP 5272 DI 10.1021/jf990011f PG 6 WC Agriculture, Multidisciplinary; Chemistry, Applied; Food Science & Technology SC Agriculture; Chemistry; Food Science & Technology GA 267RZ UT WOS:000084374200071 PM 10606607 ER PT J AU Majidi, V Qvarnstrom, J Tu, Q Frech, W Thomassen, Y AF Majidi, V Qvarnstrom, J Tu, Q Frech, W Thomassen, Y TI Improving sensitivity for CE-ICP-MS using multicapillary parallel separation SO JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY LA English DT Article ID PLASMA-MASS-SPECTROMETRY; CAPILLARY ELECTROPHORESIS; ELEMENTAL SPECIATION; INTERFACE AB A multicapillary, capillary electrophoresis inductively coupled plasma mass spectrometry interface is described. This interface allows for higher sample loading to improve the overall sensitivity and analyte detection limits without sacrificing the separation efficiencies. The results obtained with this parallel system are presented for a cross flow nebulizer. A comparison of single capillary electrophoresis for both DIHEN and cross flow nebulizers is presented. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Umea Univ, Dept Chem Analyt Chem, S-90187 Umea, Sweden. Natl Inst Occupat Hlth, N-0033 Oslo, Norway. RP Majidi, V (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 13 TC 37 Z9 39 U1 0 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. PY 1999 VL 14 IS 12 BP 1933 EP 1935 DI 10.1039/a906100b PG 3 WC Chemistry, Analytical; Spectroscopy SC Chemistry; Spectroscopy GA 265MB UT WOS:000084247000022 ER PT J AU Von Dreele, RB AF Von Dreele, RB TI Combined Rietveld and stereochemical restraint refinement of a protein crystal structure SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article ID RAY-POWDER DIFFRACTION AB By combining high-resolution X-ray powder diffraction data and stereochemical restraints, Rietveld refinement of protein crystal structures has been shown to be feasible. A refinement of the 1261-atom protein metmyoglobin was achieved by combining 5338 stereochemical restraints with a 4648-step (d(min) = 3.3 Angstrom) powder diffraction pattern to give the residuals R-wp = 2.32%, R-p = 1.66%, R(F-2) = 3.10%. The resulting tertiary structure of the protein is essentially identical to that obtained from previous single-crystal studies. C1 Univ Calif Los Alamos Natl Lab, Manuel Lujan Jr Neutron Scattering Ctr, Los Alamos, NM 87545 USA. RP Von Dreele, RB (reprint author), Univ Calif Los Alamos Natl Lab, Manuel Lujan Jr Neutron Scattering Ctr, MS H805, Los Alamos, NM 87545 USA. NR 23 TC 53 Z9 53 U1 1 U2 7 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD DEC 1 PY 1999 VL 32 BP 1084 EP 1089 DI 10.1107/S002188989901064X PN 6 PG 6 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 265DW UT WOS:000084226900006 ER PT J AU Yang, P Engler, O Klaar, HJ AF Yang, P Engler, O Klaar, HJ TI Orientation relationship between Al6Mn precipitates and the Al matrix during continuous recrystallization in Al-1.3%Mn SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article ID ALLOY AB Annealing of cold-rolled supersaturated Al-1.3 wt% Mn leads to heavy precipitation of fine particles on the as-deformed microstructure. Depending on the crystallographic orientation of the deformed matrix grains, particles with different morphologies, namely spherical, rhomboidal and plate-like, have been observed. This variation in morphology could be traced back to differences in local misorientation caused by different dislocation substructures in different matrix orientations. Microstructural investigations and selected-area diffraction (SAD) analysis in a transmission electron microscopy (TEM) study were employed to, characterize the various particles and to determine their orientation relationship to the Al matrix. Independent of the particle morphology, most Mn precipitates were identified as Al6Mn; only occasionally was Al12Mn observed. Upon consideration of the various crystal symmetries, two different orientation relationships were discerned, which can be written as (110(m)parallel to(111)(p), [001](m)parallel to[(2) over bar 11](p) and (110(m)parallel to(111)(p), [1 (1) over bar 2](m)parallel to[1 (2) over bar 1](p). These orientation relationships are discused with respect to the existence of several low misfits of lattice spacings and compared to literature data. C1 Rhein Westfal TH Aachen, Inst Met Kunde & Met Phys, D-52056 Aachen, Germany. Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. Rhein Westfal TH Aachen, GFE, D-52056 Aachen, Germany. RP Yang, P (reprint author), Rhein Westfal TH Aachen, Inst Met Kunde & Met Phys, Kopernikusstr 14, D-52056 Aachen, Germany. NR 18 TC 11 Z9 11 U1 0 U2 6 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD DEC 1 PY 1999 VL 32 BP 1105 EP 1118 DI 10.1107/S0021889899010870 PN 6 PG 14 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 265DW UT WOS:000084226900009 ER PT J AU Peters, JW Bellamy, HD AF Peters, JW Bellamy, HD TI Extension of Fe MAD phases in the structure determination of a multiple [FeS] cluster containing hydrogenase SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article ID PROGRAM AB The structure of the hydrogenase (CpI) from Clostridium pasteurianum has been solved by MAD phasing taking advantage of the presence of 20 Fe atoms in the native similar to 60 kD protein. The Fe atoms in this protein are distributed into five [FeS] clusters that could easily be identified in Patterson maps. Although the individual sites for the Fe atoms within the [FeS] cluster could not be identified directly, phasing to the maximum resolution (25 Angstrom) of the MAD data was achieved by an iterative assignment and refinement of the positions of individual Fe atoms based mainly on the known structure of several of the metal clusters. After the majority of the Fe atoms had been successfully assigned and refined in this manner, excellent quality electron-density maps were obtained which allowed the amino acid chain to be traced. C1 Utah State Univ, Dept Chem & Biochem, Logan, UT 84322 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Peters, JW (reprint author), Utah State Univ, Dept Chem & Biochem, Logan, UT 84322 USA. OI Peters, John/0000-0001-9117-9568 NR 15 TC 1 Z9 1 U1 1 U2 2 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD DEC 1 PY 1999 VL 32 BP 1180 EP 1182 DI 10.1107/S0021889899010821 PN 6 PG 3 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 265DW UT WOS:000084226900018 ER PT J AU Whiteman, CD Ban, X Sutherland, JL AF Whiteman, CD Ban, X Sutherland, JL TI Wintertime surface wind patterns in the Colorado River Valley. (vol 38, pg 1118, 1999) SO JOURNAL OF APPLIED METEOROLOGY LA English DT Correction C1 Pacific NW Natl Lab, Richland, WA USA. RP Whiteman, CD (reprint author), Battelle NW Labs, K9-30,POB 999, Richland, WA 99352 USA. NR 2 TC 0 Z9 0 U1 1 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD DEC PY 1999 VL 38 IS 12 BP 1777 EP 1777 DI 10.1175/1520-0450(1999)038<1777:C>2.0.CO;2 PG 1 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 273ZB UT WOS:000084738300009 ER PT J AU Soo, YL Huang, S Kao, YH Deb, SK Ramanathan, K Takizawa, T AF Soo, YL Huang, S Kao, YH Deb, SK Ramanathan, K Takizawa, T TI Migration of constituent atoms and interface morphology in a heterojunction between CdS and CuInSe2 single crystals SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ABSORPTION FINE-STRUCTURE; X-RAY-FLUORESCENCE; SCATTERING; HETEROSTRUCTURES; ROUGHNESS AB Angular dependence of x-ray fluorescence (ADXRF), x-ray absorption fine structure (XAFS), and grazing incidence x-ray scattering measurements were carried out using synchrotron radiation for a study of the interface morphology and migration of constituent atoms in a heterojunction formed between CdS and CuInSe2 single crystals. The advantage of using a single crystal for this study is to avoid the usually complicated problems arising from multiple phases of the Cu-In-Se compounds. By a comparison of the results obtained with a bare CuInSe2 single crystal, the changes of interface microstructures in the CdS/CuInSe2 heterojunction system with well-defined stoichiometry can therefore be investigated. Prominent features in the ADXRF data clearly demonstrate that both Cu and Se atoms have migrated into the CdS layer in the heterojunction while In atoms remain intact in the CuInSe2 single crystal. The local structures around Cu in the system also show a significant change after the deposition of CdS, as manifested by the appearance of new Cd near neighbors in the XAFS spectra. (C) 1999 American Institute of Physics. [S0021-8979(99)02223-9]. C1 SUNY Buffalo, Dept Phys, Amherst, NY 14260 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. Nihon Univ, Tokyo 102, Japan. RP SUNY Buffalo, Dept Phys, Amherst, NY 14260 USA. NR 18 TC 10 Z9 10 U1 1 U2 2 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 DEC 1 PY 1999 VL 86 IS 11 BP 6052 EP 6058 DI 10.1063/1.371653 PG 7 WC Physics, Applied SC Physics GA 256ML UT WOS:000083729000019 ER PT J AU Karapetrov, G Cambel, V Kwok, WK Nikolova, R Crabtree, GW Zheng, H Veal, BW AF Karapetrov, G Cambel, V Kwok, WK Nikolova, R Crabtree, GW Zheng, H Veal, BW TI Contactless characterization of melt-textured superconducting junctions using micro-Hall sensor arrays SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SINGLE-CRYSTALS; GROWTH AB We use spatially resolved Hall-probe magnetometry and magneto-optical imaging to study current-carrying properties of melt-textured high-temperature superconducting welds at high magnetic fields. Magneto-optical images show no deterioration of the current-carrying properties of the sample in the presence of the superconducting weld. The study of the vortex dynamics near the junction using high-resolution Hall-probe magnetometry revealed enhanced relaxation of the magnetization at the junction at high temperatures. We attribute this behavior to an increased local concentration of defects near the weld that, depending on the temperature range, either facilitates enhanced relaxation or strengthens the local pinning properties. (C) 1999 American Institute of Physics. [S0021-8979(99)08223-7]. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Slovak Acad Sci, Inst Elect Engn, SK-84239 Bratislava, Slovakia. RP Karapetrov, G (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Karapetrov, Goran/C-2840-2008 OI Karapetrov, Goran/0000-0003-1113-0137 NR 16 TC 14 Z9 14 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 DEC 1 PY 1999 VL 86 IS 11 BP 6282 EP 6286 DI 10.1063/1.371686 PG 5 WC Physics, Applied SC Physics GA 256ML UT WOS:000083729000057 ER PT J AU Pecharsky, VK Gschneidner, KA AF Pecharsky, VK Gschneidner, KA TI Heat capacity near first order phase transitions and the magnetocaloric effect: An analysis of the errors, and a case study of Gd-5(Si2Ge2) and Dy SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID GADOLINIUM; TEMPERATURE; DYSPROSIUM; ERBIUM; FIELD AB The heat capacity measured in an adiabatic heat pulse calorimeter with nonzero heat capacity suffers from intrinsic errors in the vicinity of a first order phase transition. When these errors are carried over into the calculation of the magnetocaloric effect, the latter also suffers from large systematic errors. The sources of the intrinsic errors in the heat capacity near the first order phase transition temperature and the procedures to minimize them are discussed. The experimental heat capacity data of Gd-5(Si2Ge2) and ultra pure Dy, both of which exhibit first order phase transition, are used to confirm the theoretical conclusions. (C) 1999 American Institute of Physics. [S0021-8979(99)06323-9]. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. RP Pecharsky, VK (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 29 TC 41 Z9 45 U1 2 U2 9 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 DEC 1 PY 1999 VL 86 IS 11 BP 6315 EP 6321 DI 10.1063/1.371734 PG 7 WC Physics, Applied SC Physics GA 256ML UT WOS:000083729000064 ER PT J AU Hull, JR Cansiz, A AF Hull, JR Cansiz, A TI Vertical and lateral forces between a permanent magnet and a high-temperature superconductor SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID T-C SUPERCONDUCTOR; ENERGY-STORAGE; LEVITATION-SYSTEM; RESTORING FORCE; STIFFNESS; BEARINGS; FLYWHEEL; VIBRATION; FRICTION; CERAMICS AB The vertical and horizontal forces and associated stiffnesses on a permanent magnet (PM) above a high-temperature superconductor (HTS) were measured during vertical and horizontal traverses in zero-field cooling (ZFC) and in field cooling (FC). In ZFC, the vertical stiffness was greater in the first descent than in the first ascent and second descent, and the stiffness in the second descent was between those of the first descent and the first ascent. At the FC position, the vertical stiffness was two times greater than the lateral stiffness at each height, to within 1% of the vertical stiffness value. The cross stiffness of vertical force with respect to lateral position was positive for FC, but negative for ZFC. Free-spin-down experiments of a PM levitated above a HTS were also performed. These results showed that the coefficient of friction is double valued at frequencies just below the rotor resonance, a result attributed to cross stiffness in the PM/HTS interaction. A frozen-image model was used to calculate the vertical and horizontal forces and stiffnesses, and reasonable agreement with the data occurred for vertical or horizontal movements of the PM less than several mm from the FC position. (C) 1999 American Institute of Physics. [S0021-8979(99)03223-5]. C1 Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. RP Hull, JR (reprint author), Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. RI Cansiz, Ahmet/A-5885-2012 NR 31 TC 157 Z9 159 U1 3 U2 35 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 DEC 1 PY 1999 VL 86 IS 11 BP 6396 EP 6404 DI 10.1063/1.371703 PG 9 WC Physics, Applied SC Physics GA 256ML UT WOS:000083729000076 ER PT J AU Edwards, BC Anderson, JE Epstein, RI Mills, GL Mord, AJ AF Edwards, BC Anderson, JE Epstein, RI Mills, GL Mord, AJ TI Demonstration of a solid-state optical cooler: An approach to cryogenic refrigeration SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID FREQUENCY UP-CONVERSION; CONDENSED-PHASE; LASER; TEMPERATURE; GLASSES AB We report the successful operation of an optical cooler system. This device achieved 48 degrees C of cooling from room temperature and a heat lift of 25 mW when it was pumped with 1.6 W of laser light. Its performance as a function of pump laser wavelength and chamber temperature agrees well with theoretical models. This device validates the physics needed for exploiting the laser cooling of solids to develop practical optical refrigerators. (C) 1999 American Institute of Physics. [S0021-8979(99)08923-9]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Ball Aerosp & Technol Corp, Boulder, CO 80306 USA. RP Edwards, BC (reprint author), Univ Calif Los Alamos Natl Lab, Mail Stop D436, Los Alamos, NM 87545 USA. NR 22 TC 76 Z9 81 U1 1 U2 7 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 DEC 1 PY 1999 VL 86 IS 11 BP 6489 EP 6493 DI 10.1063/1.371713 PG 5 WC Physics, Applied SC Physics GA 256ML UT WOS:000083729000087 ER PT J AU Knapp, JA Myers, SM Follstaedt, DM Petersen, GA AF Knapp, JA Myers, SM Follstaedt, DM Petersen, GA TI Extreme precipitation strengthening in ion-implanted nickel SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID MECHANICAL-PROPERTIES; SINGLE-CRYSTALS; NANOINDENTATION; ALLOYS; ALUMINUM; OXYGEN; DIFFUSION; TITANIUM; HARDNESS; LAYERS AB Precipitation strengthening of nickel was investigated using ion-implantation alloying and nanoindentation testing for particle separations in the nanometer range and volume fractions extending above 10%. Ion implantation of either oxygen alone or oxygen plus aluminum at room temperature was shown to produce substantial strengthening in the ion-treated layer, with yield strengths near 5 GPa in both cases. After annealing to 550 degrees C the oxygen-alone layer loses much of the benefit, with its yield strength reduced to 1.2 GPa, but the dual ion-implanted layer retains a substantially enhanced yield strength of over 4 GPa. Examination by transmission electron microscopy showed very fine dispersions of 1-5 nm diameter NiO and gamma-Al2O3 precipitates in the implanted layers before annealing. The heat treatment at 550 degrees C induced ripening of the NiO particles to sizes ranging from 7 to 20 nm, whereas the more stable gamma-Al2O3 precipitates were little changed. The extreme strengthening we observe is in semiquantitative agreement with predictions based on the application of dispersion-hardening theory to these microstructures. (C) 1999 American Institute of Physics. [S0021-8979(99)09123-9]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Knapp, JA (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 29 TC 10 Z9 10 U1 2 U2 4 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 DEC 1 PY 1999 VL 86 IS 11 BP 6547 EP 6556 DI 10.1063/1.371620 PG 10 WC Physics, Applied SC Physics GA 256ML UT WOS:000083729000096 ER PT J AU Bose, DN Ahrenkiel, RK Bhunia, S AF Bose, DN Ahrenkiel, RK Bhunia, S TI Steady-state and time-resolved photoconductivity measurements of minority carrier lifetime in ZnTe SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID RECOMBINATION; GROWTH AB Minority carrier lifetime in ZnTe has been determined from steady-state and time-resolved photoconductivity (PC) measurements. Three types of single crystal p-ZnTe (E-G = 2.26 eV) grown by the Bridgman technique were studied: (i) as-grown, before and after hydrogen passivation, (ii) Zn annealed, and (iii) In-doped semi-insulating. Steady-state photoconductivity was studied between 80 and 300 K and showed that for as-grown samples, the lifetime went through a sharp maximum of 4.5 x 10(-7) s at 220 K, decreasing to 2.5 x 10(-8) s at 300 K. For hydrogen passivated samples, the low temperature behavior was similar but the lifetime remained high at 4.5 x 10(-7) s at 300 K, due to passivation of deep acceptors O-Te. Time-resolved photoconductivity measurements gave a value of 4.6 x 10(-8) s for as-grown ZnTe in reasonably good agreement and 3.2 x 10(-7) s for Zn annealed and 3.1 x 10(-7) s for SI-ZnTe. The radiative recombination constant B was thus found to be 1.4 x 10(-9) and 4 x 10(-10) cm(3) s(-1), respectively, at 300 K for as-grown and Zn-annealed samples. PC spectral response studies showed a maximum at 2.41 eV at 300 K corresponding to the main valence-conduction band transition as well as a feature near 3.2 eV corresponding to the splitoff band. Slight shift in peak energy to 2.43 eV occurred on H surface passivation due to reduction of surface recombination velocity. (C) 1999 American Institute of Physics. [S0021-8979(99)00223-6]. C1 Indian Inst Technol, Ctr Mat Sci, Kharagpur 721302, W Bengal, India. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Bose, DN (reprint author), Indian Inst Technol, Ctr Mat Sci, Kharagpur 721302, W Bengal, India. RI Bhunia, Satyaban/B-4213-2008 NR 8 TC 7 Z9 7 U1 0 U2 6 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 DEC 1 PY 1999 VL 86 IS 11 BP 6599 EP 6601 DI 10.1063/1.371629 PG 3 WC Physics, Applied SC Physics GA 256ML UT WOS:000083729000106 ER PT J AU Percus, JK Percus, OE Bruno, WJ Torney, DC AF Percus, JK Percus, OE Bruno, WJ Torney, DC TI Asymptotics of pooling design performance SO JOURNAL OF APPLIED PROBABILITY LA English DT Article DE approximation techniques; asymptotic analysis; combinatorial designs; discrete probability AB We analyse the expected performance of various group testing, or pooling, designs. The context is that of identifying characterized clones in a large collection of clones. Here we choose as performance criterion the expected number of unresolved 'negative' clones, and we aim to minimize this quantity. Technically, long inclusion-exclusion summations are encountered which, aside from being computationally demanding, give little inkling of the qualitative effect of parametric control on the pooling strategy. We show that readily-interpreted re-summation can be performed, leading to asymptotic forms and systematic corrections. We apply our results to randomized designs, illustrating how they might be implemented for approximating combinatorial formulae. C1 NYU, Courant Inst Math Sci, New York, NY 10021 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Percus, JK (reprint author), NYU, Courant Inst Math Sci, 251 Mercer St, New York, NY 10021 USA. NR 17 TC 3 Z9 3 U1 0 U2 0 PU APPLIED PROBABILITY TRUST PI SHEFFIELD PA THE UNIVERSITY, SCHOOL MATHEMATICS STATISTICS, SHEFFIELD S3 7RH, ENGLAND SN 0021-9002 J9 J APPL PROBAB JI J. Appl. Probab. PD DEC PY 1999 VL 36 IS 4 BP 951 EP 964 PG 14 WC Statistics & Probability SC Mathematics GA 291EZ UT WOS:000085722300001 ER PT J AU Pekour, MS Coulter, RL AF Pekour, MS Coulter, RL TI A technique for removing the effect of migrating birds in 915-MHz wind profiler data SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article AB A method is described and evaluated for decreasing artifacts in radar wind profiler data resulting from overflying, migrating birds. The method processes the prerecorded, averaged spectral data of a wind profiler to derive hourly wind profiles during conditions of frequent backscattering from birds. Comparison with in situ measurements revealed a significant improvement over the "traditional," online processing routine. When both the traditional method and the proposed new method are applied to an extended dataset, a practical procedure can be implemented to detect periods with significant bird-caused artifacts. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Coulter, RL (reprint author), Argonne Natl Lab, 9700 S Cass Ave,Bldg 203,Room J155, Argonne, IL 60439 USA. NR 12 TC 6 Z9 7 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD DEC PY 1999 VL 16 IS 12 BP 1941 EP 1948 DI 10.1175/1520-0426(1999)016<1941:ATFRTE>2.0.CO;2 PG 8 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 271EK UT WOS:000084581100005 ER PT J AU Pickering, IJ George, GN Van Fleet-Stalder, V Chasteen, TG Prince, RC AF Pickering, IJ George, GN Van Fleet-Stalder, V Chasteen, TG Prince, RC TI X-ray absorption spectroscopy of selenium-containing amino acids SO JOURNAL OF BIOLOGICAL INORGANIC CHEMISTRY LA English DT Article DE selenomethionine; selenocysteine; selenocystine; X-ray absorption spectroscopy ID ESCHERICHIA-COLI AB The selenium K-edge X-ray absorption spectra of selenomethionine, selenocysteine, selenocystine, and sulfo-selenocystine in solution are compared with the corresponding sulfur K-edge spectra of the sulfur analogues of these compounds. The selenium and sulfur spectra follow similar trends, although the latter are significantly sharper owing to the longer core hole lifetime at the lower energies where sulfur absorbs. The spectra of the selenium compounds are sufficiently distinct that it is reasonable to expect that curve fitting will allow the speciation of the forms of selenium in complex biological samples. C1 Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. Sam Houston State Univ, Dept Chem, Huntsville, TX 77341 USA. Sam Houston State Univ, Texas Res Inst Environm Studies, Huntsville, TX 77341 USA. Exxon Res & Engn Co, Annandale, NJ 08801 USA. RP Pickering, IJ (reprint author), Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RI Chasteen, Thomas/B-6601-2009; George, Graham/E-3290-2013; Pickering, Ingrid/A-4547-2013; OI Pickering, Ingrid/0000-0002-0936-2994 FU NIGMS NIH HHS [GM57375] NR 12 TC 51 Z9 51 U1 0 U2 15 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0949-8257 J9 J BIOL INORG CHEM JI J. Biol. Inorg. Chem. PD DEC PY 1999 VL 4 IS 6 BP 791 EP 794 DI 10.1007/s007750050352 PG 4 WC Biochemistry & Molecular Biology; Chemistry, Inorganic & Nuclear SC Biochemistry & Molecular Biology; Chemistry GA 262MY UT WOS:000084072100015 PM 10631611 ER PT J AU Bryan, JC Sachleben, RA AF Bryan, JC Sachleben, RA TI Synthesis of a new dibenzo-14-crown-4 lariat ether and structure of its sodium perrhenate complex SO JOURNAL OF CHEMICAL CRYSTALLOGRAPHY LA English DT Article DE crown ether; crystal structure; lariat; sodium ID CRYSTAL-STRUCTURE; PHOSPHINIC ACID; MOLECULES; LITHIUM; CATIONS; ALKALI AB A dibenzo-14-crown-4 ether with a novel monooxyacetone sidearm is prepared and its structure with sodium perrhenate is determined. The structure crystallizes in P2(1)/c with cell dimensions: a = 8.107(2) Angstrom, b = 28.138(3) Angstrom, c = 10.293(2) Angstrom, and beta = 104.173(9)degrees; giving a volume of 2276.6(7) Angstrom(3). This structure is compared to other sodium complexes of dibenzo-14-crown-4 lariat ethers and is found to be the only one with intramolecular bonding between the sidearm and the cation. Possible reasons for this observation are discussed. C1 Oak Ridge Natl Lab, Chem & Analyt Sci Div, Oak Ridge, TN 37831 USA. RP Bryan, JC (reprint author), Oak Ridge Natl Lab, Chem & Analyt Sci Div, Oak Ridge, TN 37831 USA. RI G, Neela/H-3016-2014 NR 19 TC 2 Z9 2 U1 1 U2 2 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 DEC PY 1999 VL 29 IS 12 BP 1255 EP 1259 DI 10.1023/A:1009552806586 PG 5 WC Crystallography; Spectroscopy SC Crystallography; Spectroscopy GA 347KZ UT WOS:000088929700005 ER PT J AU Skurski, P Gutowski, M Simons, J AF Skurski, P Gutowski, M Simons, J TI Mixed valence/dipole-bound dianions SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MULTIPLY-CHARGED ANIONS; ELECTRON-AFFINITIES; DIPOLE; STATES; STABILITIES AB The possibility of binding two electrons to a molecule utilizing two distinct electron binding sites (i.e., one valence- and one dipole-binding center) is studied using ab initio electronic structure methods. It is found that if the electron binding energy of the dipole-binding site is large enough to overcome the Coulomb repulsion produced by the valence-bound electron, the dianion can be electronically stable with respect to the corresponding monoanion. It is also found that, for reasonable dipole- and valence-binding strengths, the separation between the two sites can be small enough to render the species within the current realm of synthetic possibility. Numerical results are presented for the dianions of LiCN ... LiCC-PF5 and LiCN ... LiCN ... LiCC-PF5, whose vertical electronic stabilities are 0.120 and 0.808 eV, and whose stabilities with respect to fragmentation (i.e., loss of LiCN-) are 3.9 and 36.5 kcal/mol [including zero point energy (ZPE)], respectively. (C) 1999 American Institute of Physics. [S0021-9606(99)30744-3]. C1 Univ Utah, Dept Chem, Henry Eyring Ctr Theoret Chem, Salt Lake City, UT 84112 USA. Pacific NW Lab, Richland, WA 99352 USA. Univ Gdansk, Dept Chem, PL-80952 Gdansk, Poland. RP Simons, J (reprint author), Univ Utah, Dept Chem, Henry Eyring Ctr Theoret Chem, Salt Lake City, UT 84112 USA. NR 33 TC 12 Z9 12 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 DEC 1 PY 1999 VL 111 IS 21 BP 9469 EP 9474 DI 10.1063/1.480277 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 255TC UT WOS:000083685400004 ER PT J AU Jarvis, GK Song, Y Ng, CY Grant, ER AF Jarvis, GK Song, Y Ng, CY Grant, ER TI A characterization of vibrationally and electronically excited NO2+ by high-resolution threshold photoionization spectroscopy SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ENERGY PHOTOELECTRON-SPECTROSCOPY; MULTIBUNCH SYNCHROTRON-RADIATION; STRETCH FERMI RESONANCE; MOLECULES; STATE; IONS AB The pulsed-field ionization zero-electron kinetic-energy (PFI-ZEKE) threshold photoionization spectrum of NO2 from 9.58 to 20 eV is obtained using vacuum ultraviolet synchrotron radiation by means of the Chemical Dynamics Beamline at the Lawrence Berkeley National Laboratory Advanced Light Source. The high resolution afforded by PFI threshold discrimination yields new or refined spectroscopic constants for a number of known excited states of the cation, including the first estimate of the A rotational constant in the a B-3(2) state, as well as new fundamental frequencies for the A (1)A(2) and B B-1(2) states, a precise determination of the singlet-triplet splitting in the c B-3(1)-C B-1(1) complex and the first observations of the states, d (3)A(1) and D B-1(2). Most significantly, ZEKE photoelectron detection resolves vibrational structure in the linear X (1)Sigma(g)(+) ground state of NO2+. Vibrational positions in the first electron volt of the spectrum are found to conform with the predictions of a Hamiltonian that includes Fermi resonance and other anharmonic terms derived from earlier multiresonant laser spectroscopic experiments on the lower bending excited states. (C) 1999 American Institute of Physics. [S0021-9606(99)00444-4]. C1 Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Adv Light Source, Berkeley, CA 94720 USA. Iowa State Univ, Ames Lab, US DOE, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Purdue Univ, Dept Chem, W Lafayette, IN 47907 USA. RP Jarvis, GK (reprint author), Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Adv Light Source, Berkeley, CA 94720 USA. NR 28 TC 21 Z9 21 U1 0 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 DEC 1 PY 1999 VL 111 IS 21 BP 9568 EP 9573 DI 10.1063/1.480288 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 255TC UT WOS:000083685400015 ER PT J AU Kukk, E Bozek, JD Cheng, WT Fink, RF Wills, AA Berrah, N AF Kukk, E Bozek, JD Cheng, WT Fink, RF Wills, AA Berrah, N TI Auger decay of the C 1s(-1)2 pi(*) resonance in carbon monoxide: vibrationally and angularly resolved spectra SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID AUTOIONIZATION SPECTRA; SHAPE-RESONANCE; EXCITATION; MOLECULES; STATES; SPECTROSCOPY; PHOTOELECTRON; PHOTOEMISSION; IONIZATION; EDGES AB Auger electron spectra from the decay of the nu=0, 1, and 2 levels of the C 1s(-1)2 pi* state were measured with sufficiently high electron and photon energy resolution to completely resolve the vibrational structure of the final electronic states. The results are compared with ab initio calculations with emphasis on the analysis of the spectator Auger transitions. The anisotropy parameters extracted from angle-resolved spectra show variations within the vibrational envelopes of the participator Auger decay and exhibit a complex oscillating behavior for the spectator Auger transitions. In addition, two-dimensional (2D) imaging of the electron emission across the C 1s(-1)2 pi* resonance was performed. The ratio of resonant and nonresonant ionization processes is estimated from the 2D map. Strong vibrational lifetime interference effects apparent in the 2D imaging are discussed. (C) 1999 American Institute of Physics. [S0021-9606(99)00741-2]. C1 Western Michigan Univ, Dept Phys, Kalamazoo, MI 49008 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Natl Cent Univ, Dept Phys, Chungli 32054, Taiwan. Ruhr Univ Bochum, D-44780 Bochum, Germany. RP Kukk, E (reprint author), Western Michigan Univ, Dept Phys, Kalamazoo, MI 49008 USA. RI Bozek, John/E-4689-2010; Bozek, John/E-9260-2010; Fink, Reinhold/A-3239-2016 OI Bozek, John/0000-0001-7486-7238; Fink, Reinhold/0000-0002-8288-924X NR 30 TC 37 Z9 37 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 DEC 1 PY 1999 VL 111 IS 21 BP 9642 EP 9650 DI 10.1063/1.480337 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 255TC UT WOS:000083685400025 ER PT J AU Hsu, CP Head-Gordon, M Head-Gordon, T AF Hsu, CP Head-Gordon, M Head-Gordon, T TI Reaction field cavity optimization: A born-again Born model for ionic hydration SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID POLARIZABLE CONTINUUM MODEL; INITIO MOLECULAR-DYNAMICS; AQUEOUS SOLVATION; FREE-ENERGIES; SOLVENT; DENSITY; EQUILIBRIA; IMPLEMENTATION; DISTRIBUTIONS; MECHANICS AB We present a new quantum reaction field model, the electronic reaction field (ERF), which does not require the empirical specification of cavity shape and size. We demonstrate our approach on one of the simplest reaction field theories, the Born model for aqueous atomic ion solvation. The ERF model enforces complete solute-solvent separability so that the solute wave function is optimized under the boundary condition that it is fully contained within the cavity. This model imposes the exact condition necessary for treating the solute quantum mechanically and the other as a macroscopic classical dielectric, and allows the testing of the primary assumption in the dielectric continuum approximation that the molecular character of solvent is unimportant. We show that the Born theory for monovalent and divalent cations is consistent with ERF model enforcing full wave function containment, while strict solute-solvent separability gives a poor description for anions of any valency. (C) 1999 American Institute of Physics. [S0021-9606(99)51245-2]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Phys Biosci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP Head-Gordon, M (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Head-Gordon, Teresa/E-5818-2011; Hsu, Chao-Ping/E-1303-2011 OI Hsu, Chao-Ping/0000-0002-7187-427X NR 32 TC 7 Z9 7 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 DEC 1 PY 1999 VL 111 IS 21 BP 9700 EP 9704 DI 10.1063/1.480303 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 255TC UT WOS:000083685400033 ER PT J AU Barrena, E Ocal, C Salmeron, M AF Barrena, E Ocal, C Salmeron, M TI Evolution of the structure and mechanical stability of self-assembled alkanethiol islands on Au(111) due to diffusion and ripening SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ATOMIC-FORCE MICROSCOPY; SCANNING-TUNNELING-MICROSCOPY; CHAIN-LENGTH DEPENDENCE; SUPERLATTICE STRUCTURE; ORGANIC-SURFACES; IN-SITU; MONOLAYERS; GOLD; THIOLS; ADSORPTION AB An atomic force microscope (AFM) study of the structure and stability of islands of alkanethiol (C16H33SH) grown on Au(111) is presented. Ripening processes involving long-range molecular diffusion takes place at ambient temperature in the scale of days. In the partially covered surface, ripening is manifested by an enlargement of the islands as well as by molecular densification. On the well packed islands, the c(4x2) superstructure is imaged. Another manifestation of island densification is a substantial increase in mechanical stability, as shown by the resistance of the film to penetration by the tip. The threshold pressure for molecular displacement and tip penetration was found to increase by almost 70% relative to the initial value before ripening. (C) 1999 American Institute of Physics. [S0021-9606(99)70845-7]. C1 CSIC, Inst Ciencia Mat, Dept Intercaras & Crecimiento, Madrid, Spain. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Barrena, E (reprint author), CSIC, Inst Ciencia Mat, Dept Intercaras & Crecimiento, Cantoblanco, Madrid, Spain. RI Ocal, Carmen/G-8590-2013; Barrena, Esther/B-7683-2014 OI Ocal, Carmen/0000-0001-8790-8844; Barrena, Esther/0000-0001-9163-2959 NR 35 TC 76 Z9 76 U1 1 U2 11 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 DEC 1 PY 1999 VL 111 IS 21 BP 9797 EP 9802 DI 10.1063/1.480316 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 255TC UT WOS:000083685400046 ER PT J AU Rottach, DR Tillman, PA McCoy, JD Plimpton, SJ Curro, JG AF Rottach, DR Tillman, PA McCoy, JD Plimpton, SJ Curro, JG TI The diffusion of simple penetrants in tangent site polymer melts SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MOLECULAR-DYNAMICS SIMULATION; GRADIENT-DRIVEN DIFFUSION; VELOCITY AUTOCORRELATION; INTEGRAL-EQUATION; BLENDS; MOTION; THERMODYNAMICS; POLYPROPYLENE; TRANSPORT; LIQUID AB The diffuse behavior of penetrants in simple polymer melts was investigated by molecular dynamics simulation. For the case where the polymer melt consisted of pearl-necklace chains, the diffusive behavior of the loose pearl penetrants was seen to be qualitatively different than would be expected in realistic models of polymer melts. In particular, there was little or no "non-Fickian" region; the variation of the diffusion coefficient with the penetrant diameter was what one would expect for diffusion through small molecular liquids; and, finally, the long time tail of the velocity autocorrelation displayed a "-3/2" power law form, also as in the small molecular liquid case. When the chains' backbone motion was further constrained by the introduction of a bond angle potential, the qualitative nature of the penetrant diffusion became more "polymer-like." A non-Fickian region developed; the diffusion coefficient varied more rapidly with penetrant diameter; and the velocity autocorrelation function developed a "-5/2" power law tail. (C) 1999 American Institute of Physics. [S0021-9606(99)50345-0]. C1 New Mexico Inst Min & Technol, Dept Mat & Met Engn, Socorro, NM 87801 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP McCoy, JD (reprint author), New Mexico Inst Min & Technol, Dept Mat & Met Engn, Socorro, NM 87801 USA. RI McCoy, John/B-3846-2010; Rottach, Dana/E-8350-2010 OI McCoy, John/0000-0001-5404-1404; Rottach, Dana/0000-0003-0459-5980 NR 43 TC 3 Z9 3 U1 0 U2 3 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 DEC 1 PY 1999 VL 111 IS 21 BP 9822 EP 9831 DI 10.1063/1.480318 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 255TC UT WOS:000083685400049 ER PT J AU Carlisle, JA Blankenship, SR Smith, RN Chaiken, A Michel, RP van Buuren, T Terminello, LJ Jia, JJ Callcott, TA Ederer, DL AF Carlisle, JA Blankenship, SR Smith, RN Chaiken, A Michel, RP van Buuren, T Terminello, LJ Jia, JJ Callcott, TA Ederer, DL TI Electronic structure and crystalline coherence in Fe/Si multilayers SO JOURNAL OF CLUSTER SCIENCE LA English DT Article; Proceedings Paper CT 7th Annual Workshop of the Consortium for Nanostructured Materials CY OCT 29-31, 1998 CL RICHMOND, VIRGINIA DE x-ray emission spectra; magnetic multilayers; electronic structure; thin-film growth; interlayer coupling ID X-RAY FLUORESCENCE; EMISSION; SUPERLATTICES; SILICIDES; FILMS; SI AB Soft x-ray fluorescence spectroscopy has been used to examine the electronic structure of deeply buried silicide thin films that arise in Fe/Si multilayers. These systems exhibit antiferromagnetic (AF) coupling of the Fe layers, despite their lack of a noble metal spacer layer found in most GMR materials. Also, the degree of coupling is very dependent on preparation conditions, especially spacer layer thickness and growth temperature. The valence band spectra are quite different for films with different spacerlayer thickness yet are very similar for films grown at different growth temperatures. The latter result is surprising since AF coupling is strongly dependent on growth temperature. Combining near-edge x-ray absorption with the fluorescence data demonstrates that the local bonding structure in the silicide spacer layer in epitaxial films which exhibit AF coupling are metallic. These results indicate the equal roles of crystalline coherence and electronic structure in determining the magnetic properties of these systems. C1 Virginia Commonwealth Univ, Dept Phys, Richmond, VA 23284 USA. Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Univ Tennessee, Knoxville, TN 37996 USA. Tulane Univ, New Orleans, LA 70118 USA. RP Carlisle, JA (reprint author), Virginia Commonwealth Univ, Dept Phys, Richmond, VA 23284 USA. NR 16 TC 2 Z9 2 U1 1 U2 1 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1040-7278 J9 J CLUST SCI JI J. Clust. Sci. PD DEC PY 1999 VL 10 IS 4 BP 591 EP 599 DI 10.1023/A:1021917427431 PG 9 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 256AE UT WOS:000083701700011 ER PT J AU Fitts, JP Persson, P Brown, GE Parks, GA AF Fitts, JP Persson, P Brown, GE Parks, GA TI Structure and bonding of Cu(II)-glutamate complexes at the gamma-Al2O3-water interface SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article DE adsorption; infrared spectroscopy; EXAFS spectroscopy; glutamate; copper(II); gamma-Al2O3; ternary surface complex ID COPPER(II) COMPLEXES; HUMIC SUBSTANCES; OXIDE MINERALS; ORGANIC-MATTER; TRACE-METALS; SURFACE; HYDROXIDE; IONS; PRECIPITATION; ADSORPTION AB The composition and mode of attachment of Cu(II) complexes at the gamma-Al2O3-water interface in suspensions containing a simple amino acid (glutamate) were characterized with EXAFS and FTIR spectroscopies. The spectroscopic results indicate that two types of Cu(II)-glutamate-alumina interactions are primarily responsible for Cu(II) and glutamate uptake between pH 4 and 9. In acidic suspensions of alumina, glutamate forms a bridge between Cu(II) ions and the (hydr)oxide surface (Type B complex). In this Type B surface complex, Cu(II) is bonded to amino acid headgroups (i.e., +H3NCHRCOO-) of two glutamate molecules. Spectroscopic and ionic strength dependent uptake results are combined to propose that the nonbonded side chain carboxylate groups of this complex are attracted to the oxide surface through long-range forces, leading to enhanced Cu(II) uptake relative to the glutamate-free system. In alkaline suspensions the relative amount of surface-bound Cu(II) complexed by glutamate decreases, and a direct Cu(II)-surface bond becomes the dominant mode of attachment (Type A complex). These surface complexes differ markedly from the species found in the alumina-fi ee Cu(II)glutamate aqueous system under similar solution conditions, where Cu(H2O)(6)(2+) and Cu(glutamate)(2)(2-) are the dominant species in acidic and alkaline solutions, respectively. Based on these spectroscopic results, surface complexation reactions are proposed for the Cu(II) and glutamate ternary interactions with the alumina surface in this system. Similarities between the results of this study and Cu(II) uptake behavior and complexation in the presence of natural organic material (NOM) indicate that Cu(II)-glutamate interactions mimic those in more complex Cu(II)-NOM-mineral-water systems, (C) 1999 Academic Press. C1 Stanford Univ, Dept Geol & Environm Sci, Surface & Aqueous Geochem Grp, Stanford, CA 94305 USA. Umea Univ, Dept Inorgan Chem, S-90187 Umea, Sweden. Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Fitts, JP (reprint author), Stanford Univ, Dept Geol & Environm Sci, Surface & Aqueous Geochem Grp, Stanford, CA 94305 USA. EM fitts@pangea.stanford.edu RI Persson, Per/D-7388-2012; Fitts, Jeffrey/J-3633-2012 OI Persson, Per/0000-0001-9172-3068; NR 51 TC 63 Z9 65 U1 0 U2 18 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9797 EI 1095-7103 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD DEC 1 PY 1999 VL 220 IS 1 BP 133 EP 147 DI 10.1006/jcis.1999.6521 PG 15 WC Chemistry, Physical SC Chemistry GA 257GQ UT WOS:000083774500018 ER PT J AU Marone, PA Thiyagarajan, P Wagner, AM Tiede, DM AF Marone, PA Thiyagarajan, P Wagner, AM Tiede, DM TI Effect of detergent alkyl chain length on crystallization of a detergent-solubilized membrane protein: correlation of protein-detergent particle size and particle-particle interaction with crystallization of the photosynthetic reaction center from Rhodobacter sphaeroides SO JOURNAL OF CRYSTAL GROWTH LA English DT Article DE small-angle neutron scattering; reaction center; membrane protein; detergent; heptanetriol ID ANGLE NEUTRON-SCATTERING; PHOTOCHEMICAL-REACTION CENTERS; X-RAY-DIFFRACTION; RHODOPSEUDOMONAS-SPHAEROIDES; OCTYL GLUCOSIDE; CRYSTAL-GROWTH; COMPLEX; VIRIDIS; DIAGRAM; BINDING AB The effect of detergent alkyl chain length on the crystallization of detergent-solubilized membrane proteins was characterized using the reaction center (RC) from Rhodobacter sphaeroides as a model. Crystallization was performed in the presence of both n-alkyl-beta-D-glucopyranosides, C(n)G, where the alkyl chain length, n, was varied from 8 to 10, and dodecyl-dimethylamine-N-oxide (C(12)DAO). A pronounced effect of detergent chain length was found on the ability to crystallize the reaction center. Small-angle neutron scattering measurements (SANS) demonstrated that the variation in the ability to crystallize the reaction center is correlated with changes in the apparent radius of gyration, R(g), of the reaction center-detergent particle, reflecting changes in the size of the reaction center and strength of the inter-particle interactions. Specifically, reaction center crystallization in the absence of additional amphiphiles was found to occur only with octylglucoside, C(8)G. Crystallization in the presence of longer chain detergents, C(9)G, C(10)G, C(12)DAO, required the use of an additional small amphiphile, heptanetriol (HT). SANS measurements showed that the apparent R(g) of the reaction center-detergent particle increased with increasing detergent chain length, and that the addition of HT reduces his parameter. The addition of HT was found to impede crystallization in the presence of C(8)G. This inhibition could be reversed by increasing C(8)G concentration with respect to HT, resulting in the formation of alternate crystal forms. Taken together, these results suggest that detergents and small molecule amphiphiles used in membrane protein crystallization must be chosen to optimize both the size and solubility of the protein-detergent particle. Data for the reaction center suggest that crystallization occurs within a restricted range of size of the protein-detergent complex. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP Tiede, DM (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. EM tiede@anl.gov NR 53 TC 19 Z9 20 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD DEC PY 1999 VL 207 IS 3 BP 214 EP 225 DI 10.1016/S0022-0248(99)00372-3 PG 12 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 258LZ UT WOS:000083841800007 ER PT J AU Ravindra, NM Downey, DF Marcus, SD Sopori, BL AF Ravindra, NM Downey, DF Marcus, SD Sopori, BL TI Special issue on manufacturing issues in rapid thermal processing - Foreword SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Editorial Material C1 New Jersey Inst Technol, Newark, NJ 07102 USA. Varian Ion Implant Syst, Gloucester, MA 01930 USA. STEAG AST Elect, Tempe, AZ USA. Natl Renewable Energy Lab, Golden, CO USA. RP Ravindra, NM (reprint author), New Jersey Inst Technol, Newark, NJ 07102 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 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 DEC PY 1999 VL 28 IS 12 BP 1327 EP 1327 DI 10.1007/s11664-999-0116-9 PG 1 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA 268ZB UT WOS:000084449600001 ER PT J AU Sopori, B Chen, W Madjdpour, J Ravindra, NM AF Sopori, B Chen, W Madjdpour, J Ravindra, NM TI Calculation of emissivity of Si wafers SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT 3rd Conference on Rapid Thermal Processing CY MAR, 1999 CL SAN DIEGO, CALIFORNIA SP TMS EPDMD DE emissivity; temperature; dopant concentration; silicon; multilayer ID ELEVATED-TEMPERATURES; SILICON AB A computer-software, EMISSIVITY, has been developed to calculate the emissivity (epsilon) of silicon wafers of any surface morphology, for a given temperature and dopant concentration. The software uses a combination of ray- and wave-optics approaches to include the interference and the polarization effects necessary for multilayer surface coatings and multi-reflections within thin wafers. The refractive index and the absorption coefficient are calculated as a function of temperature and dopant concentration using an empirical model for an indirect bandgap semiconductor. The results of this model are compared with conventional emissivity calculations and experimental data. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. New Jersey Inst Technol, Newark, NJ 07102 USA. RP Sopori, B (reprint author), Natl Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80401 USA. NR 12 TC 14 Z9 14 U1 0 U2 6 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 DEC PY 1999 VL 28 IS 12 BP 1385 EP 1389 DI 10.1007/s11664-999-0126-7 PG 5 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA 268ZB UT WOS:000084449600011 ER PT J AU Kroon, RE Botha, JR Neethling, JH Drummond, TJ AF Kroon, RE Botha, JR Neethling, JH Drummond, TJ TI Photoluminescence of Be implanted Si-doped GaAs SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT 3rd Conference on Rapid Thermal Processing CY MAR, 1999 CL SAN DIEGO, CALIFORNIA SP TMS EPDMD DE gallium arsenide; implantation; photoluminescence; beryllium ID P-TYPE GAAS; BAND-GAP; N-TYPE; PHOTO-LUMINESCENCE; GALLIUM-ARSENIDE; RAMAN-SCATTERING; DIFFUSION; ZN; SEMICONDUCTORS; ACTIVATION AB Degenerately doped n-type GaAs produces band-to-band luminescence with the peak energy dependent on the carrier concentration. In this study the photoluminescence of Si-doped GaAs is examined after implantation with high energy Be ions and annealing. The band-to-band peak energy in the unimplanted (reference) material is shown to be smaller than reported values in Te-doped GaAs of the same carrier concentration. This is attributed to compensation in the Si doped material as a result of its amphoteric nature. For the implanted samples, no luminescence was recorded for the unannealed samples or those annealed at 400 degrees C and 500 degrees C. Comparing the relative peak intensities from material annealed at 600 degrees C for 15 min and 30 min indicates an increase in the number of As vacancies with anneal time. For samples annealed at 700 degrees C and 800 degrees C, the dominant luminescence is associated with Ga-As antisite defects. It is suggested that formation of these defects occurs predominantly only at these higher temperatures. Crystal recovery as measured by the luminescence intensity increased with both anneal temperature and time. For the implanted sample annealed at 800 degrees C for 15 min, the dominant peak height was 25% of that from the reference sample. C1 Univ Port Elizabeth, Dept Phys, ZA-6000 Port Elizabeth, South Africa. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Kroon, RE (reprint author), Univ Port Elizabeth, Dept Phys, POB 1600, ZA-6000 Port Elizabeth, South Africa. RI Kroon, Robin/A-1793-2013 OI Kroon, Robin/0000-0001-9728-9370 NR 51 TC 3 Z9 3 U1 0 U2 0 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 DEC PY 1999 VL 28 IS 12 BP 1466 EP 1471 DI 10.1007/s11664-999-0143-6 PG 6 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA 268ZB UT WOS:000084449600028 ER PT J AU Glascoe, LG Wright, SJ Abriola, LM AF Glascoe, LG Wright, SJ Abriola, LM TI Modeling the influence of heat/moisture exchange during bioventing SO JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE LA English DT Article ID LESS-VOLATILE HYDROCARBONS; WATER-STRESS; UNSATURATED ZONE; SOIL-MOISTURE; POROUS-MEDIA; TEMPERATURE; SIMULATION; GROWTH; HEAT; BIODEGRADATION AB The presented modeling investigation examines the potential influence of advection-induced evaporation and condensation on bioventing, a vadose-zone remediation technology. Currently, few soil vapor extraction or bioventing models incorporate nonisothermal effects when considering system performance. Laboratory and field measurements suggest, however, that even small changes in temperature and moisture content can influence microbial activity and could thus affect the overall efficiency of a bioventing operation. The model here is a one-dimensional simulator that describes mass and energy transport under steady, gaseous phase flow conditions. The coupled mass and energy equations are solved using a sequential iterative solver with matric potential and temperature as primary variables. A literature-derived relation is used to quantify the combined effect of water potential and temperature change on biological growth rates. Simulations indicate that the injection of air at temperatures and/or water vapor concentrations different from the initial ambient soil conditions can induce changes in matric potential and local soil temperature, which could measurably impact biological activity. C1 Univ Calif Los Alamos Natl Lab, Div Earth & Environm Sci, Los Alamos, NM 87545 USA. Univ Michigan, Dept Civil & Environm Engn, Ann Arbor, MI 48109 USA. RP Glascoe, LG (reprint author), Univ Calif Los Alamos Natl Lab, Div Earth & Environm Sci, POB 1663, Los Alamos, NM 87545 USA. RI Abriola, Linda/F-7624-2010 NR 47 TC 2 Z9 3 U1 2 U2 3 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 DEC PY 1999 VL 125 IS 12 BP 1093 EP 1102 DI 10.1061/(ASCE)0733-9372(1999)125:12(1093) PG 10 WC Engineering, Environmental; Engineering, Civil; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 255PV UT WOS:000083679300002 ER PT J AU Mahinthakumar, G Gwo, JP Moline, GR Webb, OF AF Mahinthakumar, G Gwo, JP Moline, GR Webb, OF TI Subsurface biological activity zone detection using genetic search algorithms SO JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE LA English DT Article ID CHLORINATED ALIPHATICS; INSITU BIORESTORATION; MODEL SIMULATIONS; GROUNDWATER; SOLVE AB Use of generic search algorithms for detection of subsurface biological activity zones (BAZ) is investigated through a series of hypothetical numerical biostimulation experiments. Continuous injection of dissolved oxygen and methane with periodically varying concentration stimulates the cometabolism of indigenous methanotropic bacteria. The observed breakthroughs of methane are used to deduce possible BAZ in the subsurface. The numerical experiments are implemented in a parallel computing environment to make possible the large number of simultaneous transport simulations required by the algorithm. Our results show that genetic algorithms are very efficient in locating multiple activity zones, provided the observed signals adequately sample the BAZ. C1 Oak Ridge Natl Lab, Ctr Computat Sci, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. RP Mahinthakumar, G (reprint author), Oak Ridge Natl Lab, Ctr Computat Sci, Oak Ridge, TN 37831 USA. NR 24 TC 8 Z9 8 U1 0 U2 1 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 DEC PY 1999 VL 125 IS 12 BP 1103 EP 1112 DI 10.1061/(ASCE)0733-9372(1999)125:12(1103) PG 10 WC Engineering, Environmental; Engineering, Civil; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 255PV UT WOS:000083679300003 ER PT J AU Sheffield, J Abdou, M Briggs, R Callen, J Clarke, J Forsen, H Gebbie, K Hoffman, I Lindl, J Marmar, E Nevins, W Rosenbluth, M Tang, W Valeo, E AF Sheffield, J Abdou, M Briggs, R Callen, J Clarke, J Forsen, H Gebbie, K Hoffman, I Lindl, J Marmar, E Nevins, W Rosenbluth, M Tang, W Valeo, E TI Report of the FEAC inertial fusion energy review panel: July 1996 SO JOURNAL OF FUSION ENERGY LA English DT Article DE fusion; fusion science; fusion energy; inertial fusion energy AB This report presents the results and recommendations of the U. S. Department of Energy Fusion Energy Advisory Committee (FEAC) review of its Inertial Fusion Energy (IFE) program. The subpanel charged with the review was chaired by John Sheffield of Oak Ridge National Laboratory. The FEAC, to which the subpanel reported, was chaired by Robert Conn of the University of California at San Diego. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Sci Applicat Int Corp, Mclean, VA 22102 USA. Univ Wisconsin, Madison, WI 53706 USA. Pacific NW Natl Lab, Richland, WA 99352 USA. Gesell Schwerionenforsch mbH, Darmstadt, Germany. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. MIT, Cambridge, MA 02139 USA. Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Sheffield, J (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0164-0313 J9 J FUSION ENERG JI J. Fusion Energy PD DEC PY 1999 VL 18 IS 4 BP 195 EP 211 DI 10.1023/A:1019285807930 PG 17 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 472ZV UT WOS:000171015600001 ER PT J AU Conn, RW Baldwin, DE Briggs, RJ Callen, JD Goldston, RJ Hazeltine, RD Siemon, RE Taylor, TS AF Conn, RW Baldwin, DE Briggs, RJ Callen, JD Goldston, RJ Hazeltine, RD Siemon, RE Taylor, TS TI Panel report to FESAC: Review of the 1996 ITER detailed design report SO JOURNAL OF FUSION ENERGY LA English DT Review DE international thermonuclear experimental reactor; fusion energy ID DISRUPTIONS AB This report presents the results of a U.S. review of the 1996 Detailed Design Report (DDR) of the International Thermonuclear Experimental Reactor (ITER) project. It was prepared by a panel established by the U.S. Department of Energy (USDOE) Fusion Energy Sciences Advisory Committee (FESAC) and was subsequently endorsed by FESAC and provided to the USDOE. Copies of the charge and transmittal letters are incorporated at the end of this paper. Also incorporated in this paper are the reports of several subpanels established to provide detailed review and recommendations on specific topics. The authors of those subpanel reports are acknowledged in the text. The ITER was subsequently reduced in size and scope; this review refers to the full-size ITER design as it was completed in 1996. C1 Univ Calif San Diego, La Jolla, CA 92093 USA. Gen Atom Co, San Diego, CA 92138 USA. Sci Applicat Int Corp, Mclean, VA 22102 USA. Univ Wisconsin, Madison, WI 53706 USA. Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. Univ Texas, Austin, TX 78712 USA. Los Alamos Natl Lab, Los Alamos, NM USA. RP Conn, RW (reprint author), Univ Calif San Diego, La Jolla, CA 92093 USA. NR 25 TC 0 Z9 0 U1 2 U2 4 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0164-0313 J9 J FUSION ENERG JI J. Fusion Energy PD DEC PY 1999 VL 18 IS 4 BP 213 EP 298 DI 10.1023/A:1019247924768 PG 86 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 472ZV UT WOS:000171015600002 ER PT J AU LaBelle, J McAdams, KL Trimpi, ML AF LaBelle, J McAdams, KL Trimpi, ML TI High-frequency and time resolution rocket observations of structured low- and medium-frequency whistler mode emissions in the auroral ionosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ELECTRON-CYCLOTRON WAVES; EXOS-C SATELLITE; KILOMETRIC RADIATION; GROUND FACILITIES; RADIO EMISSIONS; PLASMA-WAVES; LOW-ALTITUDE; HISS; LATITUDES; GENERATION AB High bandwidth electric field waveform measurements on a recent auroral sounding rocket reveal structured whistler mode signals at 400-800 kHz. These are observed intermittently between 300 and 500 km with spectral densities 0-10 dB above the detection threshold of 1.5 x 10(-11) V-2/m(2) Hz. The lack of correlation with local particle measurements suggests a remote source. The Signals are composed of discrete structures, in one case having bandwidths of about 10 kHz and exhibiting rapid frequency variations of the order of 200 kHz per 100 ms. In one case, emissions near the harmonic of the whistler mode signals are detected simultaneously. Current theories of auroral zone whistler mode emissions have not been applied to explain quantitatively the fine structure of these signals, which resemble auroral kilometric radiation (AKR) rather than auroral hiss. C1 Dartmouth Coll, Dept Phys & Astron, Hanover, NH 03755 USA. RP LaBelle, J (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663,MS D466, Los Alamos, NM 87545 USA. NR 25 TC 8 Z9 8 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 DEC 1 PY 1999 VL 104 IS A12 BP 28101 EP 28107 DI 10.1029/1999JA900397 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 266UN UT WOS:000084318800009 ER PT J AU McAdams, KL LaBelle, J Trimpi, ML Kintner, PM Arnoldy, RA AF McAdams, KL LaBelle, J Trimpi, ML Kintner, PM Arnoldy, RA TI Rocket observations of banded structure in waves near the Langmuir frequency in the auroral ionosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ALIGNED ELECTRON FLUX; FLICKERING AURORA; FINE-STRUCTURE; PLASMA; FREJA AB Using data from the PHAZE II sounding rocket, launched from Poker Flat, Alaska, we present high-resolution observations of structure in auroral HF waves at and below the local plasma frequency. These observations were made in the altitude range of 390-945 km where the local plasma frequency is below the electron cyclotron frequency. We observe monochromatic, long-lived, narrowband emissions occuring below the local plasma frequency during times of intense HF wave emission. We have termed these emissions "HF bands" due to their appearance in spectrogram images. These emissions are probably identical to the "spike" emissions identified by previous observers using lower time resolution data from the AUREOL/ARCAD3 satellite which showed a narrow peak spectra below the local plasma frequency. HF bands often occur when the local plasma density is varying and are associated with regions of intense Langmuir wave generation. We investigate the hypothesis that the HF bands are created when a Langmuir wave propagates from a low-density region into a higher density region. The wave moves onto the whistler mode branch and propagates as an HF band. Theoretical calculations of propagation times of whistler mode waves support this hypothesis. C1 Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA. Cornell Univ, Dept Elect Engn, Ithaca, NY 14853 USA. Dartmouth Coll, Dept Phys & Astron, Hanover, NH 03755 USA. RP McAdams, KL (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663,MS D466, Los Alamos, NM 87545 USA. NR 24 TC 21 Z9 21 U1 0 U2 3 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 DEC 1 PY 1999 VL 104 IS A12 BP 28109 EP 28122 DI 10.1029/1999JA900379 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 266UN UT WOS:000084318800010 ER PT J AU Mulligan, T Russell, CT Anderson, BJ Lohr, DA Rust, D Toth, BA Zanetti, LJ Acuna, MH Lepping, RP Gosling, JT AF Mulligan, T Russell, CT Anderson, BJ Lohr, DA Rust, D Toth, BA Zanetti, LJ Acuna, MH Lepping, RP Gosling, JT TI Intercomparison of NEAR and Wind interplanetary coronal mass ejection observations SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID MAGNETIC CLOUDS; MODELS; AU AB Nearly 4 months of continuous interplanetary magnetic field measurements September 1997 through December 1997 have allowed us to compare four interplanetary coronal mass ejection (ICME) events seen by the NEAR and Wind spacecraft. When the spacecraft are in close proximity (separated by 1 degrees in azimuth relative to the sun) the ICMEs seen by Wind and NEAR have similar signatures as expected for structures with dimensions along the solar wind flow of similar to 0.2 AU. When the NEAR spacecraft is separated by similar to 5.4 degrees in azimuth from the Earth the vector signature of ICMEs seen at NEAR begins to differ from those seen at Wind even though the magnitude of the field in the events and the background solar wind show similarities at the two spacecraft. When the spacecraft are separated by 11.3 degrees the magnetic signatures are quite different and sometimes ICMEs are seen only at one of the two locations. Nevertheless, in all cases the magnetic helicity of the cloud structures seen at NEAR is the same as at Wind. The radial speeds of the shock and ICME leading edge as they cross Wind and the time delays of those events, for which we have some assurance that they also arrived at NEAR, indicate that the ICMEs decelerate measurably as they travel near 1 AU. C1 Univ Calif Los Angeles, IGPP, Los Angeles, CA 90096 USA. Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90096 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Mulligan, T (reprint author), Univ Calif Los Angeles, IGPP, 405 Hilgard Ave, Los Angeles, CA 90096 USA. RI Anderson, Brian/I-8615-2012 NR 23 TC 27 Z9 27 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 DEC 1 PY 1999 VL 104 IS A12 BP 28217 EP 28223 DI 10.1029/1999JA900215 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 266UN UT WOS:000084318800020 ER PT J AU Haland, S Ostgaard, N Bjordal, J Stadsnes, J Ullaland, S Wilken, B Yamamoto, T Doke, T Chenette, DL Parks, GK Brittnacher, MJ Reeves, GD AF Haland, S Ostgaard, N Bjordal, J Stadsnes, J Ullaland, S Wilken, B Yamamoto, T Doke, T Chenette, DL Parks, GK Brittnacher, MJ Reeves, GD TI Magnetospheric and ionospheric response to a substorm: Geotail HEP-LD and Polar PIXIE observations SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID DEEP GEOMAGNETIC TAIL; ENERGETIC ION BURSTS; MAGNETIC-FIELD; DISTANT MAGNETOTAIL; BOUNDARY-LAYER; PLASMA SHEET; SOLAR-WIND; SIGNATURES; PRECIPITATION; SPACECRAFT AB The High Energy Particle - Low energy particle Detector experiment (HEP-LD) on board the Geotail spacecraft and the Polar Ionospheric X-ray Imaging Experiment (PIXIE) on board the Polar satellite have been used to examine a substorm event. On December 10, 1996, around 1700 UT, a substorm event with two onsets took place. The event occurred during a weak magnetic storm that started on December 9. Several of the classical substorm features were observed during the event: reconnection and neutral-line formation in the near-Earth geomagnetic tail, injection of energetic particles at geosynchronous orbit, and particle precipitation into the ionosphere. Magnetic field line mapping of the energetic precipitation area into the geomagnetic tail shows that the substorm development on ground is closely correlated with topological changes in the near-Earth tail. In the first onset, mainly soft electrons are involved, with only a transient energetic precipitation delayed relative to the onset. The second onset about 30 min later includes both soft and energetic electrons. The source regions of both onsets are found to be located near the earthward edge of the plasma sheet, while the source region of the transient energetic precipitation during the first onset is in the distant tail. Magnetic reconnection occurs sporadically and burst-like before the onsets. Both onsets appear to be triggered by northward turning of the interplanetary magnetic field. The study also demonstrates that the concept of pseudobreakups should be used with care unless global observations are available. C1 Univ Bergen, Dept Phys, N-5007 Bergen, Norway. Univ Washington, Geophys Program, Seattle, WA 98195 USA. Lockheed Martin Adv Technol Ctr, Palo Alto, CA 94304 USA. Waseda Univ, Adv Res Inst Sci & Engn, Shinjuku Ku, Tokyo 169, Japan. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Max Planck Inst Aeron, D-37189 Katlenburg Lindau, Germany. RP Haland, S (reprint author), Univ Bergen, Dept Phys, N-5007 Bergen, Norway. RI Reeves, Geoffrey/E-8101-2011 OI Reeves, Geoffrey/0000-0002-7985-8098 NR 43 TC 7 Z9 7 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 DEC 1 PY 1999 VL 104 IS A12 BP 28459 EP 28474 DI 10.1029/1999JA900216 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 266UN UT WOS:000084318800039 ER PT J AU Ober, DM Thomsen, MF Gary, SP Gallagher, DL McComas, DJ AF Ober, DM Thomsen, MF Gary, SP Gallagher, DL McComas, DJ TI Survey of pancake-shaped warm ion distributions at geosynchronous orbit SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID PITCH ANGLE DISTRIBUTIONS; EQUATORIAL MAGNETOSPHERE; CYCLOTRON INSTABILITY; PLASMA; PROTONS; WAVES; DAYSIDE; GEOS-2; MODEL; HE+ AB It has been proposed that the electromagnetic proton cyclotron instability is a strong source of heating for the anisotropic warm ions observed at geosynchronous orbit. We present here the results of a statistical study of pancake-shaped warm ion distributions using a 1-year interval of data observed with the Los Alamos magnetospheric plasma analyzer on the geosynchronous satellite 1994-084. Our results support previous findings that pancake-shaped warm ion distributions occur more frequently on the dayside of the magnetosphere and occur very close to the plasmapause. We also confirm that the electromagnetic proton cyclotron instability is operating and is constraining the hot proton temperature anisotropy. However, our results indicate that the pancake-shaped warm ion distributions observed at geosynchronous orbit are probably not generated by this instability but must be due to a different mechanism, possibly heating by lower hybrid waves. C1 Mission Res Corp, Nashua, NH 03062 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Ober, DM (reprint author), Mission Res Corp, 1 Tara Blvd,Suite 302, Nashua, NH 03062 USA. NR 28 TC 2 Z9 2 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 DEC 1 PY 1999 VL 104 IS A12 BP 28625 EP 28632 DI 10.1029/1999JA900150 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 266UN UT WOS:000084318800051 ER PT J AU Daughton, W AF Daughton, W TI Two-fluid theory of the drift kink instability SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID THIN CURRENT SHEETS; NEUTRAL SHEET; DYNAMICS; MAGNETOTAIL; MECHANISM; STABILITY; SUBSTORM; PLASMAS; TAIL AB A simple two-fluid theory of the drift kink instability is developed. The validity of the theory is restricted to the regime where the ion gyroradius is small in comparison with the sheet thickness rho(i) << L and wavelength rho(i)kappa(y) << 1. Analytic expressions are derived for the real frequency and growth rate. For the limited region of parameter space where two-fluid theory is applicable, the analytic expressions are in excellent agreement with a full Vlasov solution. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Daughton, W (reprint author), Los Alamos Natl Lab, MS B259, Los Alamos, NM 87545 USA. EM daughton@lanl.gov RI Daughton, William/L-9661-2013 NR 31 TC 40 Z9 40 U1 0 U2 6 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 DEC 1 PY 1999 VL 104 IS A12 BP 28701 EP 28707 DI 10.1029/1999JA900388 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 266UN UT WOS:000084318800058 ER PT J AU Chen, JL Murdoch, L AF Chen, JL Murdoch, L TI Effects of electroosmosis on natural soil: Field test SO JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING LA English DT Article ID ELECTRIC-FIELDS; REMOVAL; KAOLINITE AB A unique configuration of horizontal sheet-like electrodes was used in the field at a site in Ohio that was underlain by silty clay glacial drift to induce electroosmotic flow and to characterize the effects of electroosmosis on soil properties (e.g., electrical conductivity and pH). The lower electrode was created at a depth of 2.2 m by filling a flat-lying hydraulic fracture with granular graphite, and the upper one was a metallic mesh placed at a depth of 0.4 m and covered with sand. The electrodes were attached to a DC power supply, creating an electrical gradient of 20-31 V/m and a current of 42-57 A within approximately 20 m(3) of soil. Total energy applied was 5,500 kW . h during approximate 4 months of operation. Electroosmotic flow rates of 0.6-0.8 L/h were observed during tests lasting several weeks, although total flow rate (electroosmotic plus hydraulic) was strongly influenced by fluctuations of the ground-water table. The ratio of applied current to voltage decreased from 0.9 to 0.6 A/V and was mainly due to a decrease in electrical conductivity of the soil. A low pH front developed at the anode and migrated toward the cathode. The velocity of the pH front per unit voltage gradient was 0.014 (cm/day)/(V/m). This was 40 times slower than what has been reported from laboratory experiments using kaolinite as a medium. These results confirm the feasibility of using horizontal electrodes at shallow depths, but they also underscore some important differences between the geochemical effects observed during field tests in natural soils and those seen in laboratory tests using ideal materials. C1 Univ Cincinnati, Dept Civil & Environm Engn, Cincinnati, OH 45221 USA. Clemson Univ, Dept Geol Sci, Clemson, SC 29631 USA. RP Chen, JL (reprint author), Oak Ridge Inst Sci & Educ, 5995 Ctr Hill Ave, Cincinnati, OH 45224 USA. NR 22 TC 13 Z9 15 U1 1 U2 6 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 USA SN 1090-0241 J9 J GEOTECH GEOENVIRON JI J. Geotech. Geoenviron. Eng. PD DEC PY 1999 VL 125 IS 12 BP 1090 EP 1098 DI 10.1061/(ASCE)1090-0241(1999)125:12(1090) PG 9 WC Engineering, Geological; Geosciences, Multidisciplinary SC Engineering; Geology GA 255RT UT WOS:000083684500008 ER PT J AU Faber, M Greensite, J Olejnik, S Yamada, D AF Faber, M Greensite, J Olejnik, S Yamada, D TI The vortex-finding property of maximal center (and other) gauges SO JOURNAL OF HIGH ENERGY PHYSICS LA English DT Article DE confinement; lattice gauge field theories; solitons monopoles and instantons ID VORTICES AB We argue that the "vortex-finding" property of maximal center gauge, i.e. the ability of this gauge to locate center vortices inserted by hand on any given lattice, is the key to its success in extracting the vortex content of thermalized lattice configurations. We explain how this property comes about, and why it is expected not only in maximal center gauge, but also in an infinite class of gauge conditions based on adjoint-representation link variables. In principle, the vortex-finding property can be foiled by Gribov copies. This fact is relevant to a gauge-fixing procedure devised by Kovacs and Tomboulis, where we show that the loss of center dominance, found in their procedure, is explained by a corresponding loss of the vortex-finding property. The association of center dominance with the vortex-finding property is demonstrated numerically in a number of other gauges. C1 Vienna Univ Technol, Inst Kernphys, A-1040 Vienna, Austria. Univ San Francisco, Dept Phys & Astron, San Francisco, CA 94117 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theory Grp, Berkeley, CA 94720 USA. Slovak Acad Sci, Inst Phys, SK-84228 Bratislava, Slovakia. Niels Bohr Inst, DK-2100 Copenhagen, Denmark. RP Faber, M (reprint author), Vienna Univ Technol, Inst Kernphys, A-1040 Vienna, Austria. EM faber@kph.tuwien.ac.at; greensit@quark.sfsu.edu; fyziolej@savba.sk; dyamada@quark.sfsu.edu RI Olejnik, Stefan/C-6145-2008 OI Olejnik, Stefan/0000-0002-0910-7125 NR 22 TC 14 Z9 14 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 DEC PY 1999 IS 12 AR 012 PG 23 WC Physics, Particles & Fields SC Physics GA 291UV UT WOS:000085757200012 ER PT J AU Savina, M Xu, ZY Wang, Y Pellin, M Leong, K AF Savina, M Xu, ZY Wang, Y Pellin, M Leong, K TI Pulsed laser ablation of cement and concrete SO JOURNAL OF LASER APPLICATIONS LA English DT Article DE laser ablation; decontamination; cement; concrete AB Laser ablation was investigated as a means of removing radioactive contaminants from the surface and near-surface regions of concrete from nuclear facilities. We present the results of ablation tests on cement and concrete samples using a pulsed Nd:YAG laser with fiber optic beam delivery. The laser-surface interaction was studied on model systems consisting of type I portland cement with varying amounts of either fine silica or sand in an effort to understand the effect of substrate composition on ablation rates and mechanisms. The neat cement matrix melts and vaporizes when little or no sand or aggregate is present, and energy dispersive x-ray spectroscopy showed that some chemical segregation occurs in the effluent of ablated cement. The presence of sand and aggregate particles causes the material to fracture and disaggregate on ablation, with particles on the millimeter size scale Leaving the surface. (C) 1999 Laser Institute of America. [S1042-346X(99)00506-9]. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Argonne Natl Lab, Technol Dev Div, Argonne, IL 60439 USA. Penn State Univ, Appl Res Lab, State Coll, PA 16804 USA. RP Savina, M (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Pellin, Michael/B-5897-2008 OI Pellin, Michael/0000-0002-8149-9768 NR 9 TC 11 Z9 11 U1 1 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1042-346X J9 J LASER APPL JI J. Laser Appl. PD DEC PY 1999 VL 11 IS 6 BP 284 EP 287 PG 4 WC Materials Science, Multidisciplinary; Optics; Physics, Applied SC Materials Science; Optics; Physics GA 263FC UT WOS:000084113800008 ER PT J AU Almasan, CC Cimpoiasu, E Levin, GA Zheng, H Paulikas, AP Veal, BW AF Almasan, CC Cimpoiasu, E Levin, GA Zheng, H Paulikas, AP Veal, BW TI Is there a unified description of conductivity of layered cuprates? SO JOURNAL OF LOW TEMPERATURE PHYSICS LA English DT Article; Proceedings Paper CT International Conference on Physics and Chemistry of Molecular and Oxide Superconductors (MOS-99) CY JUL 28-AUG 02, 1999 CL ROYAL INST TECHNOL, STOCKHOLM, SWEDEN SP Royal Inst Technol, Royal Swedish Acad Sci, Swedish Nat Sci, Engn Sci Res Councils, SAS, Gran Gustafsson Fdn, City of Stockholm HO ROYAL INST TECHNOL AB We present a novel approach to the analysis of the normal state in-plane sigma(ab) and out-of-plane sigma(c) conductivities of anisotropic layered crystals such as oxygen deficient YBa2Cu3Ox. It can be shown that the resistive anisotropy is determined by the ratio of the phase coherence lengths in the respective directions; i.e., sigma(ab)/sigma(c) = l(ab)(2)/l(c)(2). From the idea that at all doping levels and temperatures T the out-of-plane transport in these crystals is incoherent: follows that l(c) is T-independent, equal to the spacing l(0) between the neighboring bilayers. Thus, the T-dependence of l(ab) is given by the measured anisotropy, and sigma(ab)(l(ab)) dependence is obtained by plotting sigma(ab) vs l = (sigma(ab)/sigma(c))(1/2)l(0). The analysis of several single crystals of YBa2Cu3Ox (6.35 < x < 6.93) shows that for all of them sigma(ab)(l) is described by a universal dependence sigma(ab)/<(sigma)over bar> = f(l/(l) over bar) with doping dependent parameters <(sigma)over bar> and (l) over bar. C1 Kent State Univ, Dept Phys, Kent, OH 44242 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Almasan, CC (reprint author), Kent State Univ, Dept Phys, Kent, OH 44242 USA. NR 3 TC 4 Z9 4 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-2291 J9 J LOW TEMP PHYS JI J. Low Temp. Phys. PD DEC PY 1999 VL 117 IS 5-6 BP 1307 EP 1311 DI 10.1023/A:1022508709341 PG 5 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 269PK UT WOS:000084486600052 ER PT J AU Crabtree, GW Lopez, D Kwok, WK Safar, H Paulius, LM AF Crabtree, GW Lopez, D Kwok, WK Safar, H Paulius, LM TI Dynamic correlation in driven vortex phases SO JOURNAL OF LOW TEMPERATURE PHYSICS LA English DT Article; Proceedings Paper CT International Conference on Physics and Chemistry of Molecular and Oxide Superconductors (MOS-99) CY JUL 28-AUG 02, 1999 CL ROYAL INST TECHNOL, STOCKHOLM, SWEDEN SP Royal Inst Technol, Royal Swedish Acad Sci, Swedish Nat Sci, Engn Sci Res Councils, SAS, Gran Gustafsson Fdn, City of Stockholm HO ROYAL INST TECHNOL ID FLUX-LINE-LATTICE; HIGH-TEMPERATURE SUPERCONDUCTORS; LIQUIDS; VORTICES; FLOW AB We describe transport experiments where the spatial gradient of the driving Lorentz force is controlled. The velocity profiles induced by the Lorentz force gradient in the driven liquid and lattice vortex phases are characteristic of hydrodynamic, plastic, and elastic motion. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Univ Illinois, Chicago, IL 60680 USA. Western Michigan Univ, Kalamazoo, MI 49008 USA. RP Crabtree, GW (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 23 TC 15 Z9 15 U1 0 U2 1 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-2291 J9 J LOW TEMP PHYS JI J. Low Temp. Phys. PD DEC PY 1999 VL 117 IS 5-6 BP 1313 EP 1322 DI 10.1023/A:1022560726180 PG 10 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 269PK UT WOS:000084486600053 ER PT J AU Kimura, K Koshida, R Kwok, WK Crabtree, GW Okayasu, S Sataka, M Kazumata, Y Kadowaki, K AF Kimura, K Koshida, R Kwok, WK Crabtree, GW Okayasu, S Sataka, M Kazumata, Y Kadowaki, K TI Systematic magnetization measurements on single crystalline Bi2Sr2CaCu2O8+delta with columnar defects SO JOURNAL OF LOW TEMPERATURE PHYSICS LA English DT Article; Proceedings Paper CT International Conference on Physics and Chemistry of Molecular and Oxide Superconductors (MOS-99) CY JUL 28-AUG 02, 1999 CL ROYAL INST TECHNOL, STOCKHOLM, SWEDEN SP Royal Inst Technol, Royal Swedish Acad Sci, Swedish Nat Sci, Engn Sci Res Councils, SAS, Gran Gustafsson Fdn, City of Stockholm HO ROYAL INST TECHNOL ID VORTEX AB We have performed systematic magnetization measurements on single crystalline Bi2Sr2CaCu2O8+delta with columnar defects of B-Phi = 0.005 to 1 T by using a SQUID magnetometer. Magnetization hysteresis curves of the pristine sample show a weak irreversible behavior in the vortex liquid state, suggesting the existence of the new vortex state in the vortex liquid state. This weak irreversible region persists systematically in the samples with columnar defects even up to Bs, = 1 T. It is shown that the weak hysteresis of magnetization is sensitive to the disorder level of the sample and shifts systematically to higher temperature and field region with increasing the number of columnar defects. This behavior clearly indicates that effective pinning mechanism exists even in the vortex liquid state and generates a finite critical current. C1 Univ Tsukuba, Inst Sci Mat, Tsukuba, Ibaraki 3058573, Japan. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60435 USA. Japan Atom Energy Res Inst, Naka, Ibaraki 3191195, Japan. Nihon Adv Technol Co, Naka, Ibaraki 3191106, Japan. Japan Sci & Technol Corp, JST, CREST, Yokohama, Kanagawa, Japan. RP Kimura, K (reprint author), Univ Tsukuba, Inst Sci Mat, 1-1-1 Tennodai, Tsukuba, Ibaraki 3058573, Japan. NR 9 TC 7 Z9 7 U1 0 U2 1 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-2291 J9 J LOW TEMP PHYS JI J. Low Temp. Phys. PD DEC PY 1999 VL 117 IS 5-6 BP 1471 EP 1475 DI 10.1023/A:1022514305224 PG 5 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 269PK UT WOS:000084486600079 ER PT J AU Mota, AC Dumont, E Smith, JL AF Mota, AC Dumont, E Smith, JL TI Strong vortex pinning in the low-temperature superconducting phase of (U1-xThx)Be-13 SO JOURNAL OF LOW TEMPERATURE PHYSICS LA English DT Article; Proceedings Paper CT International Conference on Physics and Chemistry of Molecular and Oxide Superconductors (MOS-99) CY JUL 28-AUG 02, 1999 CL ROYAL INST TECHNOL, STOCKHOLM, SWEDEN SP Royal Inst Technol, Royal Swedish Acad Sci, Swedish Nat Sci, Engn Sci Res Councils, SAS, Gran Gustafsson Fdn, City of Stockholm HO ROYAL INST TECHNOL ID U1-XTHXBE13; STATE AB We have found a sharp transition at T-c2 = 350 mK in the vortex creep rate of a single crystal of (U1-xThx)Be-13 with T-c = 523 mK (x = 0.0275). For T much less than T-c2, no creep of vortices is observed in a time scale of 10(5) s, while for T-c2 < T < T-c, vortices creep at very high rates (30% of decay from a metastable configuration in the first 10(5) s at T = 400 mK). The sharp transition occurs at the same temperature at which the second jump in the specific heat appears in these samples. Similar low levels of creep rates have been reported by us in the low-T superconducting phase of UPt3.(1) C1 ETH Zurich, Festkorperphys Lab, Zurich, Switzerland. Univ Calif Los Alamos Natl Lab, Superconduct Technol Ctr, Los Alamos, NM 87545 USA. RP Mota, AC (reprint author), ETH Zurich, Festkorperphys Lab, Zurich, Switzerland. NR 6 TC 4 Z9 4 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-2291 J9 J LOW TEMP PHYS JI J. Low Temp. Phys. PD DEC PY 1999 VL 117 IS 5-6 BP 1477 EP 1481 DI 10.1023/A:1022566322062 PG 5 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 269PK UT WOS:000084486600080 ER PT J AU Pan, VM Kasatkin, AL Flis, VS Komashko, VA Svetchnikov, VL Pronin, AV Snead, CL Suenaga, M Zandbergen, HW AF Pan, VM Kasatkin, AL Flis, VS Komashko, VA Svetchnikov, VL Pronin, AV Snead, CL Suenaga, M Zandbergen, HW TI Vortex pinning/dynamics in YBCO films with J(c)(77 K)> 3 center dot 10(6) A/cm(2) studied by direct transport measurements SO JOURNAL OF LOW TEMPERATURE PHYSICS LA English DT Article; Proceedings Paper CT International Conference on Physics and Chemistry of Molecular and Oxide Superconductors (MOS-99) CY JUL 28-AUG 02, 1999 CL ROYAL INST TECHNOL, STOCKHOLM, SWEDEN SP Royal Inst Technol, Royal Swedish Acad Sci, Swedish Nat Sci, Engn Sci Res Councils, SAS, Gran Gustafsson Fdn, City of Stockholm HO ROYAL INST TECHNOL ID THIN-FILMS; YBA2CU3O7-DELTA AB Critical current density, J(c), is studied for highly biaxially-oriented YBCO thin films with J(c)(77 K) > 3 MA/cm(2) in a range of magnetic fields, temperatures, angles between magnetic field vector and film c-azis. J(c)(H, theta) is shown to be dominated by vortex interaction with high density (> 10(11) lines/cm(2)) of linear pins - edge dislocations. A model is developed to describe different vortex arrays behavior in the presence of two-dimensional square network of linear pins. C1 Inst Met Phys, UA-252142 Kiev, Ukraine. Brookhaven Natl Lab, Upton, NY 11973 USA. Delft Univ Technol, Natl Ctr HREM, NL-2628 AL Delft, Netherlands. RP Pan, VM (reprint author), Inst Met Phys, Vernadsky Blvd 36, UA-252142 Kiev, Ukraine. RI Pronin, Alexasnder/B-5908-2015 OI Pronin, Alexasnder/0000-0001-5266-9783 NR 7 TC 6 Z9 6 U1 0 U2 1 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-2291 J9 J LOW TEMP PHYS JI J. Low Temp. Phys. PD DEC PY 1999 VL 117 IS 5-6 BP 1537 EP 1541 DI 10.1023/A:1022586926605 PG 5 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 269PK UT WOS:000084486600090 ER PT J AU Zuo, F Zhang, P Su, X Brooks, JS Schlueter, JA Mohtasham, J Winter, RW Gard, GL AF Zuo, F Zhang, P Su, X Brooks, JS Schlueter, JA Mohtasham, J Winter, RW Gard, GL TI Low temperature upper critical field studies in organic superconductor beta ''-(BEDT-TTF)(2)SF5CH2CF2SO3 SO JOURNAL OF LOW TEMPERATURE PHYSICS LA English DT Article; Proceedings Paper CT International Conference on Physics and Chemistry of Molecular and Oxide Superconductors (MOS-99) CY JUL 28-AUG 02, 1999 CL ROYAL INST TECHNOL, STOCKHOLM, SWEDEN SP Royal Inst Technol, Royal Swedish Acad Sci, Swedish Nat Sci, Engn Sci Res Councils, SAS, Gran Gustafsson Fdn, City of Stockholm HO ROYAL INST TECHNOL ID LAYERED SUPERCONDUCTORS AB Lour temperature upper critical field studies have been carried out in a new organic superconductor beta "-(BEDT-TTF)(2)SF5CH2CF2SO3. For field parallel to the superconducting layers, the upper critical field determined from transport measurements exceeds the BCS Pauli limit at low temperatures. The angular dependence of the resistive transition shows that the upper critical field can be best described by a quasi-two-dimensional model with a cusp near the field parallel to the plane direction. C1 Univ Miami, Dept Phys, Coral Gables, FL 33124 USA. Florida State Univ, Natl High Magnet Field Lab, Tallahassee, FL 32306 USA. Argonne Natl Lab, Div Chem & Mat Sci, Argonne, IL 60439 USA. Portland State Univ, Dept Chem, Portland, OR 97207 USA. RP Zuo, F (reprint author), Univ Miami, Dept Phys, Coral Gables, FL 33124 USA. NR 16 TC 5 Z9 5 U1 1 U2 3 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-2291 J9 J LOW TEMP PHYS JI J. Low Temp. Phys. PD DEC PY 1999 VL 117 IS 5-6 BP 1711 EP 1715 DI 10.1023/A:1022544606558 PG 5 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 269PK UT WOS:000084486600118 ER PT J AU Aligia, AA Hallberg, K Batista, CD Ortiz, G AF Aligia, AA Hallberg, K Batista, CD Ortiz, G TI Superconductivity and topological numbers in the Hubbard chain with bond-charge interaction SO JOURNAL OF LOW TEMPERATURE PHYSICS LA English DT Article; Proceedings Paper CT International Conference on Physics and Chemistry of Molecular and Oxide Superconductors (MOS-99) CY JUL 28-AUG 02, 1999 CL ROYAL INST TECHNOL, STOCKHOLM, SWEDEN SP Royal Inst Technol, Royal Swedish Acad Sci, Swedish Nat Sci, Engn Sci Res Councils, SAS, Gran Gustafsson Fdn, City of Stockholm HO ROYAL INST TECHNOL AB We determine the quantum phase diagram of the Hubbard chain with electron-hole symmetric correlated hopping at 1/2- and 1/4-filling using geometric concepts and continuum limit field theory. The long distance behavior of various correlation functions show a very rich phase diagram with several insulating, metallic, and superconducting phases, which might be relevant to (TMTSF)(2)X compounds. The closing of charge and spin gaps are accurately resolved as topological transitions (jumps in pi of Berry phases). The metallic or insulating character of each thermodynamic phase is obtained from the ground-state expectation value of a displacement operator in reciprocal space. C1 Ctr Atom Bariloche, RA-8400 Bariloche, Rio Negro, Argentina. Inst Balseiro, Comis Nacl Energia Atom, RA-8400 Bariloche, Rio Negro, Argentina. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Aligia, AA (reprint author), Ctr Atom Bariloche, RA-8400 Bariloche, Rio Negro, Argentina. RI Batista, Cristian/J-8008-2016 NR 10 TC 7 Z9 7 U1 1 U2 1 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-2291 J9 J LOW TEMP PHYS JI J. Low Temp. Phys. PD DEC PY 1999 VL 117 IS 5-6 BP 1747 EP 1751 DI 10.1023/A:1022556909284 PG 5 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 269PK UT WOS:000084486600124 ER PT J AU Rapaport, A David, V Bass, M Deka, C Boatner, LA AF Rapaport, A David, V Bass, M Deka, C Boatner, LA TI Optical spectroscopy of erbium-doped lutetium orthophosphate SO JOURNAL OF LUMINESCENCE LA English DT Article DE photoluminescence; fluorescence decay dynamics; cross relaxation; upconversion ID SCATTERING AB Experimental spectroscopic investigations of the absorption and luminescence properties of Er3+ ions doped into single crystals of the tetragonal-symmetry host LuPO4 are reported. The LuPO4 host permits the incorporation of relatively high concentrations of lanthanide dopants such as Er3+. The fluorescence decay of the I-4(13/2)-I-4(15/2) emission was found to be governed by a single exponential decay process when excited with a low-intensity pump source. However, experiments performed on samples of different concentrations show that Er3+ ions in LuPO4. experience concentration quenching as well as self-trapping. Using high-Er-concentration samples, emissions were also observed at visible wavelengths due to up-conversion processes. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Cent Florida, Sch Opt, Orlando, FL 32816 USA. Univ Cent Florida, Ctr Res & Educ Opt & Lasers, Orlando, FL 32816 USA. Beckman Coulter Inc, Miami, FL 33195 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Bass, M (reprint author), Univ Cent Florida, Sch Opt, Orlando, FL 32816 USA. RI Boatner, Lynn/I-6428-2013 OI Boatner, Lynn/0000-0002-0235-7594 NR 15 TC 34 Z9 37 U1 2 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-2313 J9 J LUMIN JI J. Lumines. PD DEC PY 1999 VL 85 IS 1-3 BP 155 EP 161 DI 10.1016/S0022-2313(99)00060-5 PG 7 WC Optics SC Optics GA 261KW UT WOS:000084009200017 ER PT J AU Jones, JA Knill, E AF Jones, JA Knill, E TI Efficient refocusing of one-spin and two-spin interactions for NMR quantum computation SO JOURNAL OF MAGNETIC RESONANCE LA English DT Article DE spin echo; hadamard; quantum computation; graph; proper coloring ID SPECTROSCOPY AB The use of spin echoes to refocus one-spin interactions (chemical shifts) and two-spin interactions (spin-spin couplings) plays a central role in both conventional NMR experiments and NMR quantum computation. Here we describe schemes for efficient refocusing of such interactions in both fully and partially coupled spin systems. (C) 1999 Academic Press. C1 Univ Oxford, Clarendon Lab, Ctr Quantum Computat, Oxford OX1 3PU, England. Oxford Ctr Mol Sci, Oxford OX1 3QT, England. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Jones, JA (reprint author), Univ Oxford, Clarendon Lab, Ctr Quantum Computat, Parks Rd, Oxford OX1 3PU, England. RI Jones, Jonathan/E-4585-2011 OI Jones, Jonathan/0000-0003-1862-587X NR 14 TC 83 Z9 83 U1 0 U2 1 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 DEC PY 1999 VL 141 IS 2 BP 322 EP 325 DI 10.1006/jmre.1999.1890 PG 4 WC Biochemical Research Methods; Physics, Atomic, Molecular & Chemical; Spectroscopy SC Biochemistry & Molecular Biology; Physics; Spectroscopy GA 263RZ UT WOS:000084140200013 PM 10579955 ER PT J AU Wind, RA Ardenkjaer-Larsen, JH AF Wind, RA Ardenkjaer-Larsen, JH TI (1)H DNP at 1.4 T of water doped with a triarylmethyl-based radical SO JOURNAL OF MAGNETIC RESONANCE LA English DT Article DE DNP; overhauser effect; TAM radical; microwave heating; MR microscopy ID DYNAMIC NUCLEAR-POLARIZATION; LOOP-GAP RESONATOR; DIELECTRIC-PROPERTIES; C-13 NMR; SAMPLES; SOLIDS; EPR AB Recently a triarylmethyl-based (TAM) radical has been developed for research in biological and other aqueous systems, and in low magnetic fields, 10 mT or less, large (1)H dynamic nuclear polarization (DNP) enhancements have been reported. In this paper the DNP properties of this radical have been investigated in a considerably larger field of 1.4 T, corresponding to proton and electron Larmor frequencies of 60 MHz and 40 GHz, respectively. To avoid excessive microwave heating of the sample, an existing DNP NMR probe was modified with a screening coil, wound around the sample capillary and with its axis perpendicular to the electric component of the microwave field. It was found that with this probe the temperature increase in the sample after 4 s of microwave irradiation with an incident power of 10 W was only 16 degrees C. For the investigations, 10 mM of the TAM radical was dissolved in deionized, but not degassed, water and put into a l-mm i.d. and 6-mm long capillary tube. At 26 degrees C the following results were obtained: (I) The relaxivity of the radical is 0.07 (mMs)(-1), in accordance with the value extrapolated from low-field results; (II) The leakage factor is 0.63, the saturation factor at maximum power is 0.85, and the coupling factor is -0.0187. It is shown that these results agree very well with an analysis where the electron-dipolar interactions are the dominant DNP mechanism, and where the relaxation transitions resulting from these interactions are governed by translational diffusion of the water molecules. Finally, the possibilities of combining DNP with magnetic resonance microscopy (MRM) are discussed. It is shown that at 26 degrees C the overall DNP-enhanced proton polarization should become maximal in an external field of 0.3 T and become comparable to the thermal equilibrium polarization in a field of 30 T, considerably larger than the largest high-resolution magnet available to date. It is concluded that DNP MRM in this field, which corresponds to a standard microwave frequency of 9 GHz, has the potential to significantly increase the sensitivity in NMR and MRI experiments of small aqueous samples doped with the TAM radical. (C) 1999 Academic Press. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. Nycomed Innovat AB, S-20512 Malmo, Sweden. RP Wind, RA (reprint author), Pacific NW Natl Lab, POB 999,MS K8-98, Richland, WA 99352 USA. EM robert.wind@pnl.gov RI Ardenkjar-Larsen, Jan Henrik/B-5765-2017 OI Ardenkjar-Larsen, Jan Henrik/0000-0001-6167-6926 NR 31 TC 32 Z9 32 U1 0 U2 15 PU ACADEMIC PRESS INC ELSEVIER SCIENCE 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 DEC PY 1999 VL 141 IS 2 BP 347 EP 354 DI 10.1006/jmre.1999.1910 PG 8 WC Biochemical Research Methods; Physics, Atomic, Molecular & Chemical; Spectroscopy SC Biochemistry & Molecular Biology; Physics; Spectroscopy GA 263RZ UT WOS:000084140200017 PM 10579959 ER PT J AU Kortright, JB Awschalom, DD Stohr, J Bader, SD Idzerda, YU Parkin, SSP Schuller, IK Siegmann, HC AF Kortright, JB Awschalom, DD Stohr, J Bader, SD Idzerda, YU Parkin, SSP Schuller, IK Siegmann, HC TI Research frontiers in magnetic materials at soft X-ray synchrotron radiation facilities SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Review DE magnetic films; synchrotron radiation; electron spectroscopy; X-ray spectroscopy; X-ray scattering; microscopy ID QUANTUM-WELL STATES; CORE-LEVEL PHOTOEMISSION; SUPERCONDUCTING TRANSITION-TEMPERATURE; NANOMETER-SCALE MAGNETS; SPIN-DENSITY-WAVE; GD-Y SUPERLATTICE; CIRCULAR-DICHROISM; GIANT MAGNETORESISTANCE; PHOTOELECTRON DIFFRACTION; ENHANCED MAGNETORESISTANCE AB Current and anticipated future research frontiers in magnetism and magnetic materials are discussed from a perspective of soft X-ray synchrotron utilization. Topics covered include dimensionality (including effects of spatial dimensions and differing time scales), magneto-electronics, structure/property relationships, and exploratory materials, with an emphasis on challenges that limit the understanding and advancement of these areas. Many soft X-ray spectroscopies can be used to study magnetism associated with transition and rare earth metals with element- and chemical-state specificity and large cross-sections associated with dipole transitions from p --> d and d --> f states. Established electron spectroscopies, including spin-resolved techniques, yield near-surface sensitivity in conjunction with linear and circular magnetic dichroism. Emerging photon-based scattering and Faraday and Kerr magneto-optical measurements can be used beyond the near-surface region and in applied magnetic fields. Microscopies based on either electron or photon spectroscopies to image the magnetization at 50 nm resolution are also emerging, as are time-resolved measurements that utilize the natural time structure of synchrotron sources. Examples of research using these techniques to impact our fundamental understanding of magnetism and magnetic materials are given, as are future opportunities. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. IBM Corp, Almaden Res Ctr, San Jose, CA 95120 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. USN, Res Lab, Washington, DC 20375 USA. Univ Calif San Diego, Phys Dept 0319, La Jolla, CA 92093 USA. Swiss Fed Inst Technol, CH-8093 Zurich, Switzerland. RP Kortright, JB (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. EM jbkortright@lbl.gov RI Parkin, Stuart/D-2521-2012; Bader, Samuel/A-2995-2013 NR 190 TC 153 Z9 154 U1 9 U2 60 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 DEC PY 1999 VL 207 IS 1-3 BP 7 EP 44 DI 10.1016/S0304-8853(99)00485-0 PG 38 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 257MQ UT WOS:000083786000002 ER PT J AU Clatterbuck, DM Gschneidner, KA AF Clatterbuck, DM Gschneidner, KA TI Magnetic properties of RMn6Sn6 (R = Tb, Ho, Er, Tm, Lu) single crystals SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article DE single crystals; rare earths; magnetic phase diagrams; ferrimagnets; antiferromagnets; AC susceptibility; DC magnetization ID NEUTRON-DIFFRACTION; TBMN6SN6 AB Single crystals of the compounds RMn6Sn6 where R = Tb, Ho, Er, Tm, and Lu have been prepared by the flux growth technique. Their magnetic properties were studied in the temperature range from 4.5 to 500 K. TbMn6Sn6 and HoMn6Sn6 order ferrimagnetically at 450 and 410 K, respectively. Both of these compounds undergo a change in the easy axis, and this transition has been mapped as a function of held and temperature for TbMn6Sn6. The other compounds studied (R = Er, Tm, Lu) order antiferromagnetically in zero held. Tn an applied DC field, a ferrimagnetic structure is found in ErMn6Sn6 while TmMn6Sn6 exhibits at least two structures at high field, a ferrimagnetic structure and a structure that appears to be half-ferrimagnetic. In LuMn6Sn6, the moments are also partially flipped by an applied field. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. RP Gschneidner, KA (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 9 TC 67 Z9 70 U1 1 U2 6 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 DEC PY 1999 VL 207 IS 1-3 BP 78 EP 94 DI 10.1016/S0304-8853(99)00571-5 PG 17 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 257MQ UT WOS:000083786000005 ER PT J AU Portisch, H Zhou, L Rawers, JC Hillert, M Li, XD Smith, JF Schwartz, M Ul Haq, A Srivatsan, TS Noebe, RD Anson, D Arata, Y Asthana, R Bhattacharyya, S Carbonara, RS Chama, CC Frazier, W Hays, C AF Portisch, H Zhou, L Rawers, JC Hillert, M Li, XD Smith, JF Schwartz, M Ul Haq, A Srivatsan, TS Noebe, RD Anson, D Arata, Y Asthana, R Bhattacharyya, S Carbonara, RS Chama, CC Frazier, W Hays, C TI What is the most important innovation in materials science and engineering of the 20th century? SO JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE LA English DT Editorial Material C1 Nanchang Univ, Nanchang, Peoples R China. US DOE, Albany Oregon Res Ctr, Washington, DC 20585 USA. Royal Inst Technol, Stockholm, Sweden. Ohio State Univ, Columbus, OH 43210 USA. Iowa State Univ, Ames, IA 50011 USA. AQ Khan Res Labs, Islamabad, Pakistan. Univ Akron, Dept Engn Mech, Akron, OH 44325 USA. Battelle Columbus Labs, Columbus, OH 43201 USA. Osaka Univ, Suita, Osaka 565, Japan. Univ Wisconsin Stout, Menomonie, WI 54751 USA. Univ Zambia, Namibia, South Africa. RI Li, Xiaodong/B-6530-2008 NR 19 TC 0 Z9 0 U1 0 U2 2 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 1059-9495 J9 J MATER ENG PERFORM JI J. Mater. Eng. Perform. PD DEC PY 1999 VL 8 IS 6 BP 621 EP 633 PG 13 WC Materials Science, Multidisciplinary SC Materials Science GA 264NE UT WOS:000084187700002 ER PT J AU Rawers, J Tylczak, J AF Rawers, J Tylczak, J TI Fractal characterization of wear-erosion surfaces SO JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE LA English DT Article DE alumina; analysis; erosion; fractal; silicon carbide; tribology; wear ID GEOMETRY; MODEL AB Wear erosion is a complex phenomenon resulting in highly distorted and deformed surface morphologies. Most wear surface features have been described only qualitatively. In this study wear surfaces features were quantified using fractal analysis. The ability to assign numerical values to wear-erosion surfaces makes possible mathematical expressions that will enable wear mechanisms to be predicted and understood. Surface characterization came from wear-erosion experiments that included varying the erosive materials, the impact velocity, and the impact angle. Seven fractal analytical techniques were applied to micrograph images of wear-erosion surfaces. Fourier analysis was the most promising. Fractal values obtained were consistent with visual observations and provided a unique wear-erosion parameter unrelated to wear rate. C1 US DOE, Albany Res Ctr, Albany, OR 97321 USA. RP Rawers, J (reprint author), US DOE, Albany Res Ctr, Albany, OR 97321 USA. RI Tylczak, Joseph/C-7956-2009 OI Tylczak, Joseph/0000-0002-0391-2350 NR 25 TC 6 Z9 7 U1 0 U2 2 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 1059-9495 J9 J MATER ENG PERFORM JI J. Mater. Eng. Perform. PD DEC PY 1999 VL 8 IS 6 BP 669 EP 676 DI 10.1361/105994999770346431 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA 264NE UT WOS:000084187700008 ER PT J AU Misra, A Nastasi, M AF Misra, A Nastasi, M TI Evolution of tensile residual stress in thin metal films during energetic particle deposition SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID MOLECULAR-DYNAMICS; VAPOR-DEPOSITION; GRAIN-GROWTH AB Physical-vapor-deposited thin metal films often exhibit tensile residual stresses. We studied the stress evolution in thin Cr films and found that increasing bombardment with energetic particles (atoms or ions) at low energies leads to an increase of tensile stress to a maximum followed by a rapid decrease. Microstructural characterization by transmission electron microscopy revealed that two different microstructures are observed for the same level of tensile stress: films processed at low bombardment had columnar porosity while no porosity was observed in films processed at higher bombardment. The observed stress evolution is interpreted by considering how the mean interatomic distance (and hence the force) in the intercolumnar regions is modified by energetic particle bombardment. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Misra, A (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RI Misra, Amit/H-1087-2012 NR 22 TC 19 Z9 19 U1 0 U2 6 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 DEC PY 1999 VL 14 IS 12 BP 4466 EP 4469 DI 10.1557/JMR.1999.0605 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA 263ZK UT WOS:000084155000004 ER PT J AU Wang, SX Begg, BD Wang, LM Ewing, RC Weber, WJ Kutty, KVG AF Wang, SX Begg, BD Wang, LM Ewing, RC Weber, WJ Kutty, KVG TI Radiation stability of gadolinium zirconate: A waste form for plutonium disposition SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID NUCLEAR WASTE; IN-SITU; DAMAGE; IMMOBILIZATION; ZIRCONOLITE; GD2TI2O7; AMORPHIZATION; PYROCHLORE; CAZRTI2O7; CERAMICS AB Zirconate and titanate pyrochlores were subjected to 1 MeV of Kr(+) irradiation. Pyrochlores in the Gd(2)(Zr(x)Ti(1-x))(2)O(7) system (x = 0, 0.25, 0.5, 0.75, 1) showed a systematic change in the susceptibility to radiation-induced amorphization with increasing Zr content. Gd(2)Ti(2)O(7) amorphized at relatively low dose (0.2 displacement per atom at room temperature), and the critical temperature for amorphization was 1100 K. With increasing zirconium content, the pyrochlores became increasingly radiation resistant, as demonstrated by the increasing dose and decreasing critical temperature for amorphization, Pyrochlores highly-enriched in Zr (Gd(2)Zr(2)O(7), Gd(2)Zr(1.8)Mg(0.2)O(6.8), Gd(1.9)Sr(0.1)Zr(1.9)Mg(0.1)O(6.85), and Gd(1.9)Sr(0.1)Zr(1.8)Mg(0.2)O(6.75)) could not be amorphized, even at temperature as low as 25 K. C1 Univ Michigan, Dept Nucl Engn & Radiol Sci, Ann Arbor, MI 48109 USA. Pacific NW Lab, Richland, WA 99352 USA. Univ Michigan, Dept Mat Sci & Engn, Ann Arbor, MI 48109 USA. Indira Gandhi Ctr Atom Res, Mat Chem Div, Kalpakkam 60312, Tamil Nadu, India. RP Wang, SX (reprint author), Univ Michigan, Dept Nucl Engn & Radiol Sci, Ann Arbor, MI 48109 USA. RI Weber, William/A-4177-2008 OI Weber, William/0000-0002-9017-7365 NR 37 TC 269 Z9 278 U1 5 U2 67 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD DEC PY 1999 VL 14 IS 12 BP 4470 EP 4473 DI 10.1557/JMR.1999.0606 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA 263ZK UT WOS:000084155000005 ER PT J AU Siegel, MP Overmyer, DL Venturini, EL Padilla, RR Provencio, PN AF Siegel, MP Overmyer, DL Venturini, EL Padilla, RR Provencio, PN TI Stability of Tl-Ba-Ca-Cu-O superconducting thin films SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID CRITICAL-CURRENT-DENSITY; SURFACE DEGRADATION; WATER DEGRADATION; LOW-TEMPERATURE; CARBON-FILMS; YBA2CU3O7; GROWTH; DEPOSITION; OPTIMIZATION; FABRICATION AB We report the stability of TlBa2CaCu2O7 and Tl2Ba2CaCu2O8 on LaAlO3(100) epitaxial thin films, under a variety of conditions. All films are stable in acetone and methanol and with repeated thermal cycling to cryogenic temperatures. Moisture, especially vapor, degrades film quality rapidly. These materials are stable to high temperatures in either N-2 or O-2 ambients. While total degradation, resulting from Tl depletion, occurs at the same temperatures for both phases, 600 degrees C in N-2 and 700 degrees C in O-2, the onset of degradation occurs at somewhat lower temperatures for TlBa2CaCu2O7 than for Tl2Ba2CaCu2O8. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Siegel, MP (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 41 TC 1 Z9 1 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 DEC PY 1999 VL 14 IS 12 BP 4482 EP 4488 DI 10.1557/JMR.1999.0609 PG 7 WC Materials Science, Multidisciplinary SC Materials Science GA 263ZK UT WOS:000084155000008 ER PT J AU Meldrum, A Sonder, E Zuhr, RA Anderson, IM Budai, JD White, CW Boatner, LA Henderson, DO AF Meldrum, A Sonder, E Zuhr, RA Anderson, IM Budai, JD White, CW Boatner, LA Henderson, DO TI A transmission electron microscopy investigation of sulfide nanocrystals formed by ion implantation SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID SEMICONDUCTOR NANOCRYSTALS; CDSE NANOCRYSTALS; ZNS NANOCRYSTALS; BEAM SYNTHESIS; QUANTUM DOTS; SELF-ORGANIZATION; FUSED-SILICA; AMORPHIZATION; SPECTROSCOPY; SIO2-FILMS AB Ion implantation was used to form compound semiconductor nanocrystal precipitates of ZnS, CdS, and PbS in both glass and crystalline matrices. The precipitate microstructures and size distributions were investigated by cross-sectional transmission electron microscopy techniques. Several unusual features were observed, including strongly depth-dependent size variations of the ZnS precipitates and central void features in the CdS nanocrystals. The morphology and crystal structure of the nanocrystal precipitates could be controlled by selection of the host material. The size distribution and microstructural complexity were significantly reduced by implanting a low concentration of ions into a noncrystalline host, and by using multi-energy implants to give a flat concentration profile of the implanted elements. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Fisk Univ, Dept Phys, Nashville, TN 37208 USA. RP Univ Alberta, Dept Phys, Edmonton, AB T6G 2J1, Canada. RI Budai, John/R-9276-2016 OI Budai, John/0000-0002-7444-1306 NR 46 TC 35 Z9 36 U1 0 U2 3 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 DEC PY 1999 VL 14 IS 12 BP 4489 EP 4502 DI 10.1557/JMR.1999.0610 PG 14 WC Materials Science, Multidisciplinary SC Materials Science GA 263ZK UT WOS:000084155000009 ER PT J AU Dickey, EC Pint, BA Alexander, KB Wright, IG AF Dickey, EC Pint, BA Alexander, KB Wright, IG TI Oxidation behavior of platinum-aluminum alloys and the effect of Zr doping SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID OXYGEN POTENTIAL GRADIENT; BARRIER COATING LIFE; OXIDE SCALE; REACTIVE ELEMENTS; GRAIN-BOUNDARIES; GROWTH; SEGREGATION; ALPHA-AL2O3; ADHESION; ADHERENCE AB The isothermal and cyclic oxidation behavior of PtAl and PtAl + Zr was studied followed by postoxidation microstructural and microchemical analyses. Their isothermal oxidation performance at 1200 degrees C was similar to that of NiAl and NiAl + Zr. In short (1-h) cycles, the cyclic oxidation resistance of undoped PtAl was found to be substantially better than NiAl. However, with longer (100-h) cycles, little improvement in the metal consumption rate was observed relative to NiAl. The addition of Zr to PtAl significantly improved cyclic oxidation performance in both short- and long-cycle tests. Spatially resolved energy dispersive spectroscopy indicated Zr segregation to both the metal-oxide interface and Al2O3 grain boundaries. C1 Univ Kentucky, Dept Chem & Mat Engn, Lexington, KY 40506 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Dickey, EC (reprint author), Univ Kentucky, Dept Chem & Mat Engn, Lexington, KY 40506 USA. RI Pint, Bruce/A-8435-2008; Dickey, Elizabeth/A-3368-2011 OI Pint, Bruce/0000-0002-9165-3335; Dickey, Elizabeth/0000-0003-4005-7872 NR 47 TC 16 Z9 16 U1 1 U2 6 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 DEC PY 1999 VL 14 IS 12 BP 4531 EP 4540 DI 10.1557/JMR.1999.0615 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA 263ZK UT WOS:000084155000014 ER PT J AU Simner, S Hardy, J Stevenson, J Armstrong, T AF Simner, S Hardy, J Stevenson, J Armstrong, T TI Sintering mechanisms in strontium doped lanthanum chromite SO JOURNAL OF MATERIALS SCIENCE LA English DT Article AB The sintering behavior of (La0.7Sr0.3)(x)CrO3 (0.95 less than or equal to x less than or equal to 1.05) is investigated to compare liquid phase sintering phenomena occuring in stoichiometric and non-stoichiometric compositions. Shrinkage analysis revealed marked contrast between the densification characteristics of the A-site enriched (x > 1.00) and A-site depleted (x < 1.00) materials. A-site depleted samples typically exhibited a single liquid phase sintering event at 1250 degrees C attributed to the melting of an exsoluted SrCrO4 phase. A-site enriched samples indicated two rapid shrinkage events due to the melting of SrCrO4, and a Sr-2.67(CrO4)(2) phase with a melting temperature of 1450 degrees C. Sr-2.67(CrO4)(2) was shown to evolve from a decomposition reaction between SrCrO4 and La2CrO6, detected together in A-site enriched samples from 800-1000 degrees C. Maximum densities (93% theoretical density) were achieved for (La0.7Sr0.3)(x)CrO3 x = 1.00 after sintering at 1700 degrees C for two hours. (C) 1999 Kluwer Academic Publishers. C1 Pacific NW Lab, Dept Chem & Mat Sci, Richland, WA 99352 USA. RP Simner, S (reprint author), Pacific NW Lab, Dept Chem & Mat Sci, POB 999, Richland, WA 99352 USA. EM Steven.Simner@pnl.gov RI Hardy, John/E-1938-2016 OI Hardy, John/0000-0002-1699-3196 NR 27 TC 30 Z9 34 U1 0 U2 3 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-2461 EI 1573-4803 J9 J MATER SCI JI J. Mater. Sci. PD DEC PY 1999 VL 34 IS 23 BP 5721 EP 5732 DI 10.1023/A:1004745915378 PG 12 WC Materials Science, Multidisciplinary SC Materials Science GA 247NW UT WOS:000083227700005 ER PT J AU Xu, K Russell, AM Chumbley, LS Laabs, FC Gantovnik, VB Tian, Y AF Xu, K Russell, AM Chumbley, LS Laabs, FC Gantovnik, VB Tian, Y TI Characterization of strength and microstructure in deformation processed Al-Mg composites SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID NB; TITANIUM; YTTRIUM; ALLOYS AB The microstructures, mechanical properties and electrical resistivity have been evaluated for deformation processed Al-20 vol % Mg and Al-13 vol % Mg composites. The Mg second phase adopts a convoluted, ribbon shape filamentary morphology after deformation. Both the size and spacing of these filaments decreases with deformation. The strength of these composites increases exponentially with reduced spacing of Mg filaments. The electrical resistivity of these Al-Mg composites is slightly higher than that of pure Al. (C) 1999 Kluwer Academic Publishers. C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Mat Sci & Engn, Ames, IA 50011 USA. RP Xu, K (reprint author), Iowa State Univ Sci & Technol, Ames Lab, 206 Wilhelm Hall, Ames, IA 50011 USA. OI Russell, Alan/0000-0001-5264-0104 NR 15 TC 6 Z9 6 U1 0 U2 0 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 DEC PY 1999 VL 34 IS 24 BP 5955 EP 5959 DI 10.1023/A:1004772526480 PG 5 WC Materials Science, Multidisciplinary SC Materials Science GA 256GB UT WOS:000083716600002 ER PT J AU Lara-Curzio, E Russ, CM AF Lara-Curzio, E Russ, CM TI On the relationship between the parameters of the distributions of fiber diameters, breaking loads, and fiber strengths SO JOURNAL OF MATERIALS SCIENCE LETTERS LA English DT Article ID COMPOSITES C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Lara-Curzio, E (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. NR 6 TC 18 Z9 18 U1 1 U2 4 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 DEC PY 1999 VL 18 IS 24 BP 2041 EP 2044 DI 10.1023/A:1006762622887 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA 269BT UT WOS:000084456400020 ER PT J AU Edwards, DA Goldstein, B Cohen, DS AF Edwards, DA Goldstein, B Cohen, DS TI Transport effects on surface-volume biological reactions SO JOURNAL OF MATHEMATICAL BIOLOGY LA English DT Article DE biomolecular reactions; rate constants; singular perturbations; asymptotics; integral equations ID PLASMON RESONANCE; MACROMOLECULAR INTERACTIONS; MASS-TRANSPORT; BINDING; DIFFUSION; CONSTANTS; KINETICS; RECEPTOR; LIGAND AB Many cellular reactions involve a reactant in solution binding to or dissociating from a reactant confined to a surface. This is true as well for a BIAcore(TM), an optical biosensor that is widely used to study the interaction of biomolecules. In the flow cell of this instrument, one of the reactants is immobilized on a flat sensor surface while the other reactant hows past the surface. Both diffusion and convection Flay important roles in bringing the reactants into contact. Usually BIAcore(TM) binding data are analyzed using well known expressions that are valid only in the reaction-limited case when the Damkohler number Da is small. Asymptotic and singular perturbation techniques are used to analyze dissociation of the bound state when Da is small and O(1). Linear and nonlinear integral equations result from the analysis explicit and asymptotic solutions are constructed for physically realizable cases. In addition, effective rate constants are derived that illustrate the effects of transport on the measured rate constants. All these expressions provide a direct way to estimate the rate constants from BIAcore(TM) binding data. C1 Univ Delaware, Dept Math Sci, Newark, DE 19716 USA. Univ Calif Los Alamos Natl Lab, Theoret Biol & Biophys Grp, Los Alamos, NM 87545 USA. CALTECH, Appl Math Opt, Pasadena, CA 91125 USA. RP Edwards, DA (reprint author), Univ Delaware, Dept Math Sci, 501 Ewing Hall, Newark, DE 19716 USA. NR 11 TC 33 Z9 33 U1 0 U2 5 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0303-6812 J9 J MATH BIOL JI J. Math. Biol. PD DEC PY 1999 VL 39 IS 6 BP 533 EP 561 DI 10.1007/s002850050011 PG 29 WC Biology; Mathematical & Computational Biology SC Life Sciences & Biomedicine - Other Topics; Mathematical & Computational Biology GA 269BC UT WOS:000084455000004 PM 10672509 ER PT J AU Hoffman, GG AF Hoffman, GG TI Even moments of a polymer chain distribution SO JOURNAL OF MATHEMATICAL PHYSICS LA English DT Article AB An algorithm is presented for the evaluation of the even moments of the end-to-end separation of a polymer chain. The only assumption made in the distribution function is that the energy of the chain depends only on the individual bond lengths of the chain. This assumption covers many of the commonly used distribution functions. (C) 1999 American Institute of Physics. [S0022-2488(99)02512-8]. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Florida Int Univ, Dept Chem, Miami, FL 33199 USA. RP Hoffman, GG (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 18 TC 0 Z9 0 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 DEC PY 1999 VL 40 IS 12 BP 6626 EP 6637 DI 10.1063/1.533111 PG 12 WC Physics, Mathematical SC Physics GA 256NG UT WOS:000083731000030 ER PT J AU Griffiths, SK Hruby, JM Ting, A AF Griffiths, SK Hruby, JM Ting, A TI The influence of feature sidewall tolerance on minimum absorber thickness for LIGA x-ray masks SO JOURNAL OF MICROMECHANICS AND MICROENGINEERING LA English DT Article AB Minimizing mask absorber thickness is an important practical concern in producing very small features by the LIGA dagger process. To assist in this minimization, we have developed coupled numerical models describing both the exposure and development of a thick polymethyl methacrylate (PMMA) resist. The exposure model addresses multi-wavelength, one-dimensional x-ray transmission through multiple beam filters, through the mask substrate and absorber, and the subsequent attenuation and photon absorption in the PMMA resist. The development model describes one-dimensional dissolution of a feature and its sidewalls, taking into account the variation in absorbed dose through the PMMA thickness. These exposure and development models are coupled in a single interactive code, permitting the automated adjustment of mask absorber thickness to yield a prescribed sidewall taper or dissolution distance. We have used this tool to compute the minimum required absorber thickness yielding a prescribed sidewall tolerance for exposures performed at the ALS, SSRL and NSLS synchrotron sources. Results are presented as a function of the absorbed dose for a range of the prescribed sidewall tolerance, feature size, PMMA thickness, mask substrate thickness and the development temperature. C1 Sandia Natl Labs, Livermore, CA 94551 USA. RP Griffiths, SK (reprint author), Sandia Natl Labs, Livermore, CA 94551 USA. NR 14 TC 11 Z9 11 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0960-1317 J9 J MICROMECH MICROENG JI J. Micromech. Microeng. PD DEC PY 1999 VL 9 IS 4 BP 353 EP 361 DI 10.1088/0960-1317/9/4/311 PG 9 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Instruments & Instrumentation; Physics, Applied SC Engineering; Science & Technology - Other Topics; Instruments & Instrumentation; Physics GA 269RN UT WOS:000084491500011 ER PT J AU Kurtis, KE Monteiro, PJM Brown, JT Meyer-Ilse, W AF Kurtis, KE Monteiro, PJM Brown, JT Meyer-Ilse, W TI High resolution transmission soft X-ray microscopy of deterioration products developed in large concrete dams SO JOURNAL OF MICROSCOPY-OXFORD LA English DT Article DE aggregate; alkali; alkali-aggregate reaction; alkali-silica reaction; concrete; dams; infrastructure; soft X-ray; X-ray microscopy ID AGGREGATE AB In concrete structures, the reaction of certain siliceous aggregates with the highly alkaline concrete pore solution produces an alkali-silicate gel that can absorb water and expand. This reaction can lead to expansion. cracking, increased permeability, and decreased strength of the concrete. Massive concrete structures, such as dams, are particularly susceptible to the damage caused by the alkali-silica reaction because of the availability of water and because massive gravity dams usually do not contain steer reinforcement to restrain the expansion. Both the cement hydration products and alkali-silica reaction products are extremely sensitive to humidity. Consequently, characterization techniques that require high vacuum or drying, as many existing techniques do, are not particularly appropriate for the study of the alkali-silica reaction because artefacts are introduced. Environmental scanning electron micrographs and scanning electron micrographs with energy dispersive X-ray analysis results demonstrate the effect of drying on the morphology and chemical composition of the alkali-silicate reaction gel. Thus, the impetus for this research was the need to observe and characterize the alkali-silica reaction and its gel product on a microscopic level in a wet environment (i.e. without introducing artefacts due to drying). Only soft X-ray transmission microscopy provides the required high spatial resolution needed to observe the reaction process in situ. The alkali-silica reaction can be observed over time, in a wet condition, and at normal pressures, features unavailable with most other high resolution techniques. Soft X-rays also reveal information on the internal structure of the sample. The purpose of this paper is to present research, obtained using transmission soft X-rap microscopy on the effect of concrete pore solution cations, namely sodium and calcium, on the product formed as a result of alkali attack. Alkali-silicate reaction (ASR) gel was obtained from the FURNAS Dam in Minas Gerais, Brazil. Images of the ASR gel in sodium hydroxide indicated dissolution and repolymerization of the silicate into a less dense form, demonstrating the expansive nature of the gel when exposed to alkalis. Ln the calcium hydroxide solution, ASR gel. silica fume, and chemical grade silica gel each reacted with the calcium ions in solution to produce a calcium silicate hydrate precursor with a lathlike, branching morphology. The distinctive spherulitic microstructure formed during this reaction was identified as the 'sheaf of wheat' morphology, previously described in the literature, In addition, the development of the sheaf of wheat morphology nas documented over time. These results suggest that of the cations studied in this investigation, it is the alkalis in concrete pore solution that produce the expansive ASR gel, while reaction with calcium ions does not result in expansion or damage to the concrete structure. More broadly, these results demonstrate the advantage of transmission soft X-ray microscopy for the study of the alkali-silica reaction, indicating the value of this technique for further studies in concrete technology. C1 Georgia Inst Technol, Sch Civil & Environm Engn, Atlanta, GA 30332 USA. Univ Calif Berkeley, Dept Civil & Environm Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. RP Kurtis, KE (reprint author), Georgia Inst Technol, Sch Civil & Environm Engn, Atlanta, GA 30332 USA. OI Kurtis, Kimberly/0000-0002-1252-7323 NR 21 TC 10 Z9 10 U1 3 U2 6 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0022-2720 J9 J MICROSC-OXFORD JI J. Microsc.-Oxf. PD DEC PY 1999 VL 196 BP 288 EP 298 PN 3 PG 11 WC Microscopy SC Microscopy GA 268VD UT WOS:000084436500003 ER PT J AU Edwards, JV Batiste, SL Gibbins, EM Goheen, SC AF Edwards, JV Batiste, SL Gibbins, EM Goheen, SC TI Synthesis and activity of NH2- and COOH-terminal elastase recognition sequences on cotton SO JOURNAL OF PEPTIDE RESEARCH LA English DT Article DE elastase; cotton; peptidocellulose; nonhealing wounds; affinity chromatography; bioconjugates; enzyme inhibition ID HUMAN-LEUKOCYTE; INHIBITORS; CELLULOSE AB The application of peptide recognition sequences of elastase to fibers of wound dressings is a possible route to inhibiting high levels of destructive elastase in the chronic wound. For this reason we have synthesized the elastase recognition sequence Val-Pro-Val on both cotton cellulose, and carboxymethylated cellulose cotton (CMC) and prepared chromatography columns of these to examine elastase retention. The tripepride was synthesized on cotton-based cellulose fibers both in sequence and as a tripeptide methyl ester. Glycine war employed as a linker of the recognition sequence to the cotton cellulose. Pretreatment of cotton cellulose with cellulase improved the substitution level of glycine. The peptidocellulose conjugates were employed asa chromatographic stationary phase to assess elastase retention. The sequence Val-Pro-Val-OMe was amino-terminally anchored to carboxymethylated cotton and demonstrated retention of up to 58% of elastase when first applied to the column. Higher repetitive retention was demonstrated subsequently. Cotton gauze similarly modified with Val-Pro-Val-Gly cellulose was compared with untreated gauze for reduction of elastase activity in buffered saline. Solutions of elastase that were treated with Val-Pro-Val-Gly cellulose cotton gauze, demonstrated reduced elastase activity. This study demonstrates the use of elastase recognition sequences as sequestering agents of elastase when attached to cotton fibers and constitutes a model far the design of peptidocellulose analogs in dressing fibers for chronic wounds. C1 USDA ARS, So Reg Res Ctr, Cotton Text Chem Res Unit, New Orleans, LA 70124 USA. Pacific NW Natl Lab, Richland, WA 99352 USA. RP Edwards, JV (reprint author), USDA ARS, So Reg Res Ctr, Cotton Text Chem Res Unit, 1100 Robert E Lee Blvd, New Orleans, LA 70124 USA. NR 23 TC 16 Z9 17 U1 0 U2 3 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 1397-002X J9 J PEPT RES JI J. Pept. Res. PD DEC PY 1999 VL 54 IS 6 BP 536 EP 543 DI 10.1034/j.1399-3011.1999.00134.x PG 8 WC Biochemical Research Methods; Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 261YZ UT WOS:000084040100010 PM 10604599 ER PT J AU Gschneidner, KA Pecharsky, VK AF Gschneidner, KA Pecharsky, VK TI The standard state of cerium SO JOURNAL OF PHASE EQUILIBRIA LA English DT Article AB Based on two studies carried out about 20 years apart, it was found that the double close-packed hexagonal beta Ce phase slowly transformed to the face-centered cubic gamma Ce phase at room temperature and ambient pressure. This indicates that gamma Ce is the stable modification at standard temperature and pressure (i.e., 298 K and 1 atm), The beta Ce <----> gamma Ce equilibrium temperature at 1 atm, the heat of transformation, the temperature/pressure phase diagram, and the heat capacities of beta Ce and gamma Ce are presented. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. RP Gschneidner, KA (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 5 TC 15 Z9 15 U1 0 U2 2 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 1054-9714 J9 J PHASE EQUILIB JI J. Phase Equilib. PD DEC PY 1999 VL 20 IS 6 BP 612 EP 614 DI 10.1361/105497199770340590 PG 3 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 262TE UT WOS:000084081900009 ER PT J AU Spieles, C Vogt, R Gerland, L Bass, SA Bleicher, M Stocker, H Greiner, W AF Spieles, C Vogt, R Gerland, L Bass, SA Bleicher, M Stocker, H Greiner, W TI Dissociation of J/psi by mesons: thermal versus nonequilibrium scenario SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Article ID HEAVY-ION COLLISIONS; QUARK-GLUON PLASMA; PB-PB INTERACTIONS; HADRONIC MATTER; NUCLEAR COLLISIONS; PSI-SUPPRESSION; 158 GEV/C; MODEL; HOT; EQUATION AB We study J/psi reaction kinetics in hadronic environments. The validity of a thermal meson gas ansatz is tested by confronting it with an alternative, nonequilibrium scenario. Heavy-ion collisions are simulated in the framework of the microscopic transport model, the ultrarelativistic quantum molecular dynamics model, taking into account the production of charmonium states through hard parton-parton interactions and subsequent rescattering with secondary hadrons assuming constant dissociation cross sections. The thermal gas and microscopic transport scenarios are shown to be very dissimilar. Estimates of J/psi survival probabilities based on thermal models of co-mover interactions in heavy-ion collisions are therefore questionable. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Univ Frankfurt, Inst Theoret Phys, D-60054 Frankfurt, Germany. Duke Univ, Dept Phys, Durham, NC 27708 USA. RP Spieles, C (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. RI Bleicher, Marcus/A-2758-2010; Stoecker, Horst/D-6173-2013 OI Stoecker, Horst/0000-0002-3282-3664 NR 31 TC 12 Z9 12 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0954-3899 J9 J PHYS G NUCL PARTIC JI J. Phys. G-Nucl. Part. Phys. PD DEC PY 1999 VL 25 IS 12 BP 2351 EP 2359 DI 10.1088/0954-3899/25/12/305 PG 9 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 268NF UT WOS:000084421900010 ER PT J AU Volkow, ND Fowler, JS Wang, GJ AF Volkow, ND Fowler, JS Wang, GJ TI Imaging studies on the role of dopamine in cocaine reinforcement and addiction in humans SO JOURNAL OF PSYCHOPHARMACOLOGY LA English DT Article DE attention-deficit disorder; cingulate gyrus; dopamine D-2 receptors; dopamine transporters; fluorodeoxyglucose; methylphenidate; orbitofrontal cortex; PET; rate dependency; ritalin ID POSITRON EMISSION TOMOGRAPHY; DEFICIT HYPERACTIVITY DISORDER; BRAIN GLUCOSE-METABOLISM; IN-VIVO MICRODIALYSIS; THREO-METHYLPHENIDATE; NONHUMAN-PRIMATES; INTRAVENOUS METHYLPHENIDATE; TRANSPORTER OCCUPANCY; ENDOGENOUS DOPAMINE; SYNAPTIC DOPAMINE AB We summarize our studies with positron emission tomography investigating the role of dopamine (DA) in the reinforcing effects of cocaine and methylphenidate in humans and its involvement in cocaine addiction. These studies have shown that the rate at which cocaine and methylphenidate enter the brain and block the dopamine transporters (DAT) is the variable associated with the 'high', rather than the presence per se of the drug in the brain. Our studies also show that, while the level of DAT blockade is important in predicting the intensity of the 'high' induced by these drugs (DAT blockade >50% is required for these drugs to induce a 'high'), the rate at which DAT are blocked determines whether the 'high' is perceived or not. Thus, oral methylphenidate, which leads to slow DAT blockade, does not induce a 'high: even at doses which block DAT more than 60%. In cocaine abusers, we have shown significant reductions in DA D-2 receptors that are associated with decreased metabolism in cingulate gyrus and in orbitofrontal cortex. We suggest that this is one of the mechanisms by which DA disruption leads to compulsive drug administration in cocaine addiction. Cocaine abusers also show significant decreases in DA release, which coupled with the reduction in D-2 receptors may result in decreased activation of reward circuits by physiological reinforcers and may perpetuate cocaine use as a means to compensate for this deficit. Thus, strategies to enhance DA brain function in ways that mimic physiological DA activity may be of help in overcoming cocaine addiction. C1 Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Volkow, ND (reprint author), Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. FU NIDA NIH HHS [DA06891, DA06278, DA09490] NR 62 TC 176 Z9 180 U1 0 U2 7 PU SAGE PUBLICATIONS LTD PI LONDON PA 6 BONHILL STREET, LONDON EC2A 4PU, ENGLAND SN 0269-8811 J9 J PSYCHOPHARMACOL JI J. Psychopharmacol. PD DEC PY 1999 VL 13 IS 4 BP 337 EP 345 PG 9 WC Clinical Neurology; Neurosciences; Pharmacology & Pharmacy; Psychiatry SC Neurosciences & Neurology; Pharmacology & Pharmacy; Psychiatry GA 276PA UT WOS:000084885600004 PM 10667609 ER PT J AU Raju, MR AF Raju, MR TI High-LET radiotherapy and experiences in improving rural health care in India SO JOURNAL OF RADIATION RESEARCH LA English DT Article; Proceedings Paper CT 4th International Symposium on Biological Effects of High LET Radiation CY OCT 12-14, 1998 CL HIROSHIMA UNIV, HIROSHIMA, JAPAN SP Hiroshima Univ HO HIROSHIMA UNIV DE high-LET; radiotherapy; rural health care; India ID RANDOMIZED CLINICAL-TRIAL; FAST-NEUTRONS; GAMMA-RAYS; TUMORS AB A brief back ground of high-LET radiotherapy developments and its current status will be presented. In addition, based on my experience in developing a program on cancer prevention and early detection in rural India, the gulf between sophisticated developments in cancer diagnosis and treatment and the basic needs in the developing world will be presented with some possible solutions. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87544 USA. Mahatma Gandhi Mem Med Trust, Bhimavaram 534204, Andhra Pradesh, India. RP Raju, MR (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87544 USA. NR 15 TC 3 Z9 3 U1 0 U2 0 PU JAPAN RADIATION RESEARCH SOC PI CHIBA PA C/O NAT INST RADIOLOGICAL SCI 9-1 ANAGAWA-4-CHOME INAGE-KU, CHIBA, 263, JAPAN SN 0449-3060 J9 J RADIAT RES JI J. Radiat. Res. PD DEC PY 1999 VL 40 SU S BP 74 EP 84 PG 11 WC Biology; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Radiology, Nuclear Medicine & Medical Imaging GA 316PU UT WOS:000087177600011 PM 10804997 ER PT J AU Jerde, EA Glasgow, DC AF Jerde, EA Glasgow, DC TI "Sleeping reactor" irradiations: The use of a shut-down reactor for the determination of elements with short-lived activation products SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article AB Neutron activation analysis utilizing the High Flux Isotope Reactor (HFIR) immediately following SCRAM is a workable solution to obtaining data for ultra-short lived species, principally Al, Ti, Mg, and V. Neutrons are produced in the HFIR core within the beryllium reflector due to gamma-ray bombardment from the spent fuel element. This neutron flux is not constant, varying by over two orders of magnitude during the first 24 hours. The problems associated with irradiation in a changing neutron flux are removed through the use of a specially tailored activation equation. This activation equation is applicable to any irradiation at HFIR in the first 24 hours after SCRAM since the fuel elements are identical from cycle to cycle, and the gamma-emitting nuclides responsible for the neutrons reach saturation during the fuel cycle. Reference material tests demonstrate that this method is successful, and detection limit estimates reveal:that it should be applicable to materials of widely ranging mass and composition. C1 Amer Technol Inc, Oak Ridge, TN 37830 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Jerde, EA (reprint author), Amer Technol Inc, 154 Fairbanks Rd, Oak Ridge, TN 37830 USA. NR 9 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD DEC PY 1999 VL 242 IS 3 BP 753 EP 759 DI 10.1007/BF02347390 PG 7 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 263WL UT WOS:000084148200025 ER PT J AU Volkan, M Stokes, DL Vo-Dinh, T AF Volkan, M Stokes, DL Vo-Dinh, T TI A new surface-enhanced Raman scattering substrate based on silver nanoparticles in sol-gel SO JOURNAL OF RAMAN SPECTROSCOPY LA English DT Article ID P-AMINOBENZOIC ACID; COLLOIDAL SILVER; GOLD PARTICLES; SPECTROSCOPY; PYRIDINE; SPECTRA; SPECTROMETRY; ELECTRODE; SERS; SILICATES AB We report for the first time the development of a new surface-enhanced Raman scattering (SERS)-active silver chloride silica-glass substrate prepared by using in situ precipitation of silver chloride particles in sol-gel films as a precursor for nanoparticles of silver. The controlled precipitation of silver chloride was achieved by the reaction of silver nitrate with trichloroacetic acid, which leads to a slow release of chloride ions. Silver chloride particles were reduced to silver nanoparticles by FeSO4. 7H(2)O. The sol-gel films prepared exhibit good optical properties and induce a strong SERS effect for several model compounds, including cresyl fast violet and brilliant cresyl blue. Optimization studies of substrate preparation and coating conditions were performed and are discussed in detail. The performance of this new substrate compares favorably with those of previously developed silver-coated alumina substrates, The SERS spectra of other compounds of environmental and biological interest, such as 1-aminonaphthalene, 2-aminopyrimidine, pyridine and p-aminobenzoic acid, were investigated to illustrate the usefulness of this novel type of SERS substrate for use in chemical and biological analysis. Copyright (C) 1999 John Whey & Sons, Ltd. C1 Oak Ridge Natl Lab, Adv Monitoring Dev Grp, Oak Ridge, TN 37831 USA. Middle E Tech Univ, Fac Arts & Sci, Dept Chem, TR-06531 Ankara, Turkey. RP Vo-Dinh, T (reprint author), Oak Ridge Natl Lab, Adv Monitoring Dev Grp, Oak Ridge, TN 37831 USA. NR 37 TC 28 Z9 28 U1 3 U2 17 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0377-0486 J9 J RAMAN SPECTROSC JI J. Raman Spectrosc. PD DEC PY 1999 VL 30 IS 12 BP 1057 EP 1065 DI 10.1002/(SICI)1097-4555(199912)30:12<1057::AID-JRS474>3.0.CO;2-0 PG 9 WC Spectroscopy SC Spectroscopy GA 265FB UT WOS:000084230500003 ER PT J AU Ling, CD AF Ling, CD TI Structural relationships among bismuth-rich phases in the Bi2O3-Nb2O5, Bi2O3-Ta2O5, Bi2O3-MoO3, and Bi2O3-WO3 systems SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article ID BI2O3-V2O5 SYSTEM; CRYSTAL-STRUCTURE; TERNARY OXIDES; SOLID-SOLUTION; DELTA-PHASE; FLUORITE; CHEMISTRY; BISMUTHSESQUIOXIDE; SUPERSTRUCTURES; FAMILY AB The crystal structures of bismuth-rich phases in the Bi2O3-M2O5(M = Nb, Ta) and B2O3-M2O6 (M = W, Mo) systems are investigated, and the most probable model for the crystal structure of each phase is used to propose a crystal-chemical scheme unifying key features of these structures in terms of their relationships to a fluorite-type delta-Bi2O3-related parent structure. This scheme is based on the incorporation of pyrochlore-type structural motifs (e.g., strings of M atoms along [1 1 0](F) directions) into the underlying fluorite-type metal atom array. The relative orientations of these M atom strings and their interactions are driven by the competing requirements of overall charge-balance (a function of mol% M2O5 or M2O6) and local coordination environment (a function of the element M) within the flexible fluorite-type oxygen atom array, These interactions interrelate the oxygen atom array, the metal atom array, and the composition. As the composition moves further from pure Bi2O3, they force the abandonment of pyrochlore-type structural motifs, and hence any meaningful relationship to a fluorite-type delta-Bi2O3- related parent structure is lost. The descriptive and predictive utilities of this crystal-chemical scheme are discussed. (C) 1999 Academic Press. C1 Australian Natl Univ, Res Sch Chem, Canberra, ACT 0200, Australia. RP Ling, CD (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Ling, Chris D/B-2228-2009 OI Ling, Chris D/0000-0003-2205-3106 NR 43 TC 47 Z9 47 U1 3 U2 16 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD DEC PY 1999 VL 148 IS 2 BP 380 EP 405 DI 10.1006/jssc.1999.8467 PG 26 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA 266WW UT WOS:000084324100028 ER PT J AU Nogales, E Chiu, W AF Nogales, E Chiu, W TI Electron crystallography of biological macromolecules SO JOURNAL OF STRUCTURAL BIOLOGY LA English DT Editorial Material C1 Univ Calif Berkeley, Dept Mol & Cell Biol, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Baylor Coll Med, Verna & Marrs Mclean Dept Biochem, Natl Ctr Macromol Imaging, Houston, TX 77030 USA. RP Nogales, E (reprint author), Univ Calif Berkeley, Dept Mol & Cell Biol, 229 Stanley Hall, Berkeley, CA 94720 USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1047-8477 J9 J STRUCT BIOL JI J. Struct. Biol. PD DEC 1 PY 1999 VL 128 IS 1 BP 1 EP 2 DI 10.1006/jsbi.1999.4190 PG 2 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 268ZQ UT WOS:000084451600001 ER PT J AU Glaeser, RM AF Glaeser, RM TI Review: Electron crystallography: Present excitement, a nod to the past, anticipating the future SO JOURNAL OF STRUCTURAL BIOLOGY LA English DT Article; Proceedings Paper CT Symposium on Electron Crystallography CY DEC, 1998 CL GRANLIBAKKEN, CALIFORNIA SP M E Muller Fdn ID S-RIBOSOMAL SUBUNITS; ESCHERICHIA-COLI; 3-DIMENSIONAL RECONSTRUCTION; CRYOELECTRON MICROSCOPY; PURPLE MEMBRANE; MICROGRAPHS; RESOLUTION; PROTEIN; CRYOMICROSCOPY; SPECIMENS AB From a modest beginning with negatively stained samples of the helical T4 bacteriophage tail, electron crystallography has emerged as a powerful tool in structural biology. High-resolution density maps, interpretable in terms of an atomic structure, can be obtained from specimens prepared as well-ordered, two-dimensional crystals, and the resolution achieved with helical specimens and icosahedral viruses is approaching the same goal. A hybrid approach to determining the molecular structure of complex biological assemblies is generating great interest, in which high-resolution structures that have been determined for individual protein components are fitted into a lower resolution envelope of the large complex. With this as background, how much more can be anticipated for the future? Considerable scope still remains to improve the quality of electron microscope images. Automation of data acquisition and data processing, together with the emergence of computational speeds of 10(12) floating point operations per second or higher, will make it possible to extend high-resolution structure determination into the realm of single-particle microscopy. As a result, computational alignment of single particles, i.e., the formation of "virtual crystals," can begin to replace biochemical crystallization. Since single-particle microscopy may remain limited to "large" structures of 200 to 300 kDa or more, however, smaller proteins will continue to be studied as helical assemblies or as two-dimensional crystals. The further development of electron crystallography is thus likely to turn increasingly to the use of single particles and small regions of ordered assemblies, emphasizing more and more the potential for faster, higher throughput. (C) 1999 Academic Press. C1 Univ Calif Berkeley, Dept Mol & Cell Biol, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Glaeser, RM (reprint author), Univ Calif Berkeley, Dept Mol & Cell Biol, Berkeley, CA 94720 USA. FU NIGMS NIH HHS [GM 51487] NR 75 TC 93 Z9 96 U1 1 U2 6 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1047-8477 J9 J STRUCT BIOL JI J. Struct. Biol. PD DEC 1 PY 1999 VL 128 IS 1 BP 3 EP 14 DI 10.1006/jsbi.1999.4172 PG 12 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 268ZQ UT WOS:000084451600002 PM 10600552 ER PT J AU Han, Y Sablin, EP Nogales, E Fletterick, RJ Downing, KH AF Han, Y Sablin, EP Nogales, E Fletterick, RJ Downing, KH TI Visualizing a new binding site of ncd-motor domain on tubulin SO JOURNAL OF STRUCTURAL BIOLOGY LA English DT Article; Proceedings Paper CT Symposium on Electron Crystallography CY DEC, 1998 CL GRANLIBAKKEN, CALIFORNIA SP M E Muller Fdn ID CRYSTAL-STRUCTURE; ELECTRON CRYSTALLOGRAPHY; MICROTUBULE-MOTOR; KINESIN; MOTILITY; PROTEIN; MICROSCOPY; DROSOPHILA; ANGSTROM; MODEL AB Ncd is a microtubule minus-end directed motor of the kinesin superfamily. Previously it has been shown that ncd and kinesin motor domains share the same major binding site on microtubules. sere we report a three-dimensional EM reconstruction of negatively stained two-dimensional Zn-induced tubulin crystal sheets (Zn-sheets) decorated with the ncd motor domain at a resolution of 16 Angstrom This work has revealed a second specific binding site for the ncd motor domain. The motor binding site on the tubulin Zn-sheets spans both alpha and beta tubulin subunits. This binding site is located at a position different from the previously identified ncd binding site on microtubules and may play a role in motor function. (C) 1999 Academic Press. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Donner Lab, Div Life Sci, Berkeley, CA 94720 USA. Univ Calif San Francisco, Dept Biochem & Biophys, San Francisco, CA 94143 USA. Univ Calif Berkeley, Dept Mol & Cellular Biol, Berkeley, CA 94720 USA. RP Downing, KH (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Donner Lab, Div Life Sci, Berkeley, CA 94720 USA. FU NIAMS NIH HHS [AR42895]; NIGMS NIH HHS [GM51487] NR 31 TC 8 Z9 9 U1 0 U2 0 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1047-8477 J9 J STRUCT BIOL JI J. Struct. Biol. PD DEC 1 PY 1999 VL 128 IS 1 BP 26 EP 33 DI 10.1006/jsbi.1999.4162 PG 8 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 268ZQ UT WOS:000084451600005 PM 10600555 ER PT J AU Schmid, MF Sherman, MB Matsudaira, P Tsuruta, H Chiu, W AF Schmid, MF Sherman, MB Matsudaira, P Tsuruta, H Chiu, W TI Scaling structure factor amplitudes in electron cryomicroscopy using X-ray solution scattering SO JOURNAL OF STRUCTURAL BIOLOGY LA English DT Article; Proceedings Paper CT Symposium on Electron Crystallography CY DEC, 1998 CL GRANLIBAKKEN, CALIFORNIA SP M E Muller Fdn ID FROZEN-HYDRATED SPECIMENS; CONTRAST TRANSFER; ACROSOMAL BUNDLE; CRYSTALLOGRAPHY; RESOLUTION; MICROSCOPY; VIRUS; VISUALIZATION; FILAMENT AB The structure factors derived from electron cryomicroscopic images are modified by the contrast transfer function of the microscope's objective lens and other influences. The phases of the structure factors can be corrected in a straightforward way when the positions of the contrast transfer function rings are determined. However, corrected amplitudes are also essential to yield an accurate distribution of mass in the reconstruction. The correct scale factors for the amplitudes are difficult to evaluate for data that are merged from many different micrographs. We opt to use X-ray solution scattering intensity from a concentrated suspension of the specimen to correct the amplitudes of the spherically averaged structure factors. When this approach is applied to the three-dimensional image data of ice-embedded acrosomal bundles, the core of a filament in a three-dimensional reconstruction of the acrosomal bundle becomes denser and matches more closely the outer density ascribed to scruin, (C) 1999 Academic Press. C1 Baylor Univ, Natl Ctr Macromol Imaging, Houston, TX 77030 USA. Baylor Univ, Verna & Marrs Mclean Dept Biochem, Houston, TX 77030 USA. MIT, Whitehead Inst Biomed Res, Dept Biol, Div Bioengn & Environm Hlth, Cambridge, MA 02142 USA. Stanford Univ, Stanford Linear Accelerator Ctr, SSRL, Stanford, CA 94309 USA. RP Schmid, MF (reprint author), Baylor Univ, Natl Ctr Macromol Imaging, Houston, TX 77030 USA. RI Matsudaira, Paul/H-1475-2012 OI Matsudaira, Paul/0000-0002-8399-3276 FU NCRR NIH HHS [P41RR01209, P41RR02250]; NIGMS NIH HHS [R01GM52703] NR 26 TC 9 Z9 10 U1 0 U2 1 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1047-8477 J9 J STRUCT BIOL JI J. Struct. Biol. PD DEC 1 PY 1999 VL 128 IS 1 BP 51 EP 57 DI 10.1006/jsbi.1999.4173 PG 7 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 268ZQ UT WOS:000084451600008 PM 10600558 ER PT J AU Carlson, BC AF Carlson, BC TI Toward symbolic integration of elliptic integrals SO JOURNAL OF SYMBOLIC COMPUTATION LA English DT Article ID TABLE AB A method is proposed by which elliptic integrals can be integrated symbolically without information regarding limits of integration and branch points of the integrand that is required in integral tables using Legendre's integrals. However, it is assumed that when all polynomials in the integrand have been factored symbolically into linear factors, the exponents of all distinct linear factors are known. The recurrence relations are one-parameter relations, all formulas are given explicitly, and the integral is eventually expressed in terms of canonical R-functions, with no increase in their number if neither limit of integration is a branch point of the integrand. It is the use of R-functions rather than Legendre's integrals that makes it possible to carry out the whole process symbolically. If (possibly complex) numerical values of the symbols are known, there are published algorithms for numerical computation of the R-functions. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Math, Ames, IA 50011 USA. RP Carlson, BC (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 17 TC 7 Z9 7 U1 0 U2 1 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0747-7171 J9 J SYMB COMPUT JI J. Symb. Comput. PD DEC PY 1999 VL 28 IS 6 BP 739 EP 753 DI 10.1006/jsco.1999.0336 PG 15 WC Computer Science, Theory & Methods; Mathematics, Applied SC Computer Science; Mathematics GA 286CK UT WOS:000085425900002 ER PT J AU Seifert, PK Kaelin, B Johnson, LR AF Seifert, PK Kaelin, B Johnson, LR TI Effect on ultrasonic signals of viscous pore fluids in unconsolidated sand SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article ID SEDIMENTARY-ROCKS; MEDIA; ATTENUATION; VELOCITY; PROPAGATION AB Ultrasonic attenuation measurements in unconsolidated: sand with pore fluids ranging in viscosity between 0.001 and 1 Pa.s were compared with the predictions of fluid how and scattering theories. Laboratory experiments were performed for P waves propagating through sand samples saturated with water, castor oil and two different silicone oils. The attenuation shows a frequency squared dependence for all measurements, regardless of viscosity,lin the:range between 100 and 1000 kHz. The results show that for unconsolidated sand, fluid how models which imply significant effects of the viscous pore fluids on ultrasonic waves cannot explain the laboratory measurements. The main attenuation effects observed in the laboratory can be Simulated with a three-dimensional generalized dynamic composite elastic medium model, which includes scattering from the pores and grains as well as intrinsic attenuation caused by the viscous pore fluids. For the studied sand samples, scattering is the main attenuation mechanism for ultrasonic P waves. (C) 1999 Acoustical Society of America. [S0001-4966(99)03612-7]. C1 Univ Calif Berkeley, Dept Geol & Geophys, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Ctr Computat Seismol, Berkeley, CA 94720 USA. RP Seifert, PK (reprint author), McKinsey & Co, Munich, Germany. NR 26 TC 10 Z9 10 U1 2 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD DEC PY 1999 VL 106 IS 6 BP 3089 EP 3094 DI 10.1121/1.428162 PG 6 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA 266YW UT WOS:000084328700007 ER PT J AU Biswas, P Senior, C Chang, R Vidic, R Laudal, D Brown, T AF Biswas, P Senior, C Chang, R Vidic, R Laudal, D Brown, T TI Mercury measurement and its control: What we know, have learned, and need to further investigate SO JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION LA English DT Editorial Material C1 Univ Cincinnati, Aerosol & Air Qual Res Lab, Crit Review Comm Chair, Cincinnati, OH 45221 USA. PSI Technol, Andover, MA USA. Univ Pittsburgh, Pittsburgh, PA 15260 USA. Univ N Dakota, Grand Forks, ND 58201 USA. US DOE, Fed Energy Technol Ctr, Washington, DC 20585 USA. RP Biswas, P (reprint author), Univ Cincinnati, Aerosol & Air Qual Res Lab, Crit Review Comm Chair, Cincinnati, OH 45221 USA. NR 2 TC 12 Z9 12 U1 0 U2 12 PU AIR & WASTE MANAGEMENT ASSOC PI PITTSBURGH PA ONE GATEWAY CENTER, THIRD FL, PITTSBURGH, PA 15222 USA SN 1047-3289 J9 J AIR WASTE MANAGE JI J. Air Waste Manage. Assoc. PD DEC PY 1999 VL 49 IS 12 BP 1469 EP 1473 PG 5 WC Engineering, Environmental; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 263RT UT WOS:000084139600010 ER PT J AU Sickafus, KE Hughes, R AF Sickafus, KE Hughes, R TI Spinel compounds: Structure and property relations SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Editorial Material C1 Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. Pala Int Collector, Fallbrook, CA 92028 USA. RP Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. NR 21 TC 22 Z9 24 U1 1 U2 12 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0002-7820 EI 1551-2916 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD DEC PY 1999 VL 82 IS 12 BP 3277 EP 3278 PG 2 WC Materials Science, Ceramics SC Materials Science GA 291XD UT WOS:000085763900001 ER PT J AU Sickafus, KE Wills, JM Grimes, NW AF Sickafus, KE Wills, JM Grimes, NW TI Structure of spinel SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article; Proceedings Paper CT 100th Annual Meeting of the American-Ceramic-Society CY MAY 03-06, 1998 CL CINCINNATI, OH SP Amer Ceram Soc ID SPACE GROUP; MGAL2O4 SPINEL; TEMPERATURE-DEPENDENCE; TRANSITION; DISORDER AB This paper reviews the crystal structure of compounds with the general formula AB(2)X(4), which crystallize with the same atomic structure as the mineral spinel, MgAl2O4. Three degrees of freedom associated with the detailed atomic arrangements of spinels are considered here: (i) the lattice parameter, a; (ii) the anion parameter, a; and (iii) the cation inversion parameter, i. Oxide spinels are used as examples to explore the interrelationships between these parameters. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Aston Univ, Birmingham B4 7ET, W Midlands, England. RP Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 75 TC 390 Z9 399 U1 19 U2 144 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0002-7820 EI 1551-2916 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD DEC PY 1999 VL 82 IS 12 BP 3279 EP 3292 PG 14 WC Materials Science, Ceramics SC Materials Science GA 291XD UT WOS:000085763900002 ER PT J AU Sheldon, RI Hartmann, T Sickafus, KE Ibarra, A Scott, BL Argyriou, DN Larson, AC Von Dreele, RB AF Sheldon, RI Hartmann, T Sickafus, KE Ibarra, A Scott, BL Argyriou, DN Larson, AC Von Dreele, RB TI Cation disorder and vacancy distribution in nonstoichiometric magnesium aluminate spinel, MgO center dot xAl(2)O(3) SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article; Proceedings Paper CT 100th Annual Meeting of the American-Ceramic-Society CY MAY 03-06, 1998 CL CINCINNATI, OHIO SP Amer Ceram Soc ID ANGLE SPINNING NMR; MGAL2O4 SPINEL AB Neutron diffractometry and X-ray diffractometry were used to characterize the cation disorder and vacancy distribution in nonstoichiometric spinel, MgO . xAl(2)O(3), where x greater than or equal to 1.0. Both synthetic and natural samples were examined. Least-squares refinements of integrated intensities for single crystals and Rietveld profile refinements for powders yielded the average scattering "power" from tetrahedral and octahedral sites within the almost-perfect cubic close-packed oxygen sublattice. The cation disorder was calculated assuming models in which the vacancies resided on tetrahedral, octahedral, or both types of sites. No degree of cation disorder was consistent with the tetrahedral vacancy model, and vacancies most likely resided on octahedral sites. C1 Univ Calif Los Alamos Natl Lab, Nucl Mat & Technol Div, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Mat Sci & Technol Div, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Los Alamos Neutron Sci Ctr, Los Alamos, NM 87545 USA. CIEMAT, E-28040 Madrid, Spain. RP Sheldon, RI (reprint author), Univ Calif Los Alamos Natl Lab, Nucl Mat & Technol Div, POB 1663, Los Alamos, NM 87545 USA. RI Scott, Brian/D-8995-2017 OI Scott, Brian/0000-0003-0468-5396 NR 24 TC 29 Z9 30 U1 2 U2 6 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD DEC PY 1999 VL 82 IS 12 BP 3293 EP 3298 PG 6 WC Materials Science, Ceramics SC Materials Science GA 291XD UT WOS:000085763900003 ER PT J AU Mitchell, TE AF Mitchell, TE TI Dislocations and mechanical properties of MgO-Al2O3 spinel single crystals SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article; Proceedings Paper CT 100th Annual Meeting of the American-Ceramic-Society CY MAY 03-06, 1998 CL CINCINNATI, OHIO SP Amer Ceram Soc ID MG-AL SPINEL; ELASTIC-CONSTANTS; DEFORMATION; DEPENDENCE; ANISOTROPY AB MgO . nAl(2)O(3) spinel single crystals can be deformed plastically at high temperatures, displaying a range of interesting features. Stress-strain curves often exhibit strong work hardening followed by prominent work softening due to glide and climb processes. The critical resolved shear stress (CRSS) at a given temperature decreases dramatically, by almost 2 orders of magnitude, with increasing deviation from stoichiometry, i.e., as n increases from 1 to 3.5. The CRSS is proportional to exp(-T/T-0) and to [V-c](-2), where T is the temperature in kelvin, T-0 a characteristic temperature, and [V-c] the concentration of charge-compensating cation vacancies. The Burgers vector is 1/2(110), and slip can occur on {111} and {110} planes. Slip on (111) planes is believed to occur between the Kagome cation layer and the adjacent anion layer. Slip on (110) planes is slightly easier (and has a higher T-0), because the planes are more widely separated. The temperature dependence of the CRSS can be explained in terms of the Peierls stress for partial dislocations, either in terms of a steep and high Peierls potential or in terms of temperature and stress-dependent kink diffusion. The dependence of CRSS on [V-c](-2) can be explained in terms of kink nucleation at cation vacancies. C1 Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. RP Mitchell, TE (reprint author), Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. NR 65 TC 68 Z9 68 U1 2 U2 19 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD DEC PY 1999 VL 82 IS 12 BP 3305 EP 3316 PG 12 WC Materials Science, Ceramics SC Materials Science GA 291XD UT WOS:000085763900005 ER PT J AU Moshopoulou, EG AF Moshopoulou, EG TI Superconductivity in the spinel compound LiTi2O4 SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article; Proceedings Paper CT 100th Annual Meeting of the American-Ceramic-Society CY MAY 03-06, 1998 CL CINCINNATI, OH SP Amer Ceram Soc ID ELECTRON-PHONON INTERACTION; NORMAL STATE PROPERTIES; PENETRATION-DEPTH; LATTICE-DYNAMICS; SINGLE-CRYSTALS; TERNARY-SYSTEM; LI1+XTI2-XO4; LI-1-XTI2O4; TRANSITION; EVOLUTION AB LiTi2O4 has been the subject of considerable experimental and theoretical interest since the discovery of its superconductivity by Johnston et al.(1) This unique, low-T-c (11.2 K) spinel oxide superconductor exhibits unusual characteristics, and interestingly, it presents properties that depend on various defects of the spinel structure. This article reviews experimental and theoretical studies of LiTi2O4 and discusses the basic, unresolved issues regarding the physics of this system. Special emphasis is given to methods for preparing the compound and to the structure-properties relationship. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 66 TC 31 Z9 31 U1 3 U2 41 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0002-7820 EI 1551-2916 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD DEC PY 1999 VL 82 IS 12 BP 3317 EP 3320 PG 4 WC Materials Science, Ceramics SC Materials Science GA 291XD UT WOS:000085763900006 ER PT J AU Thackeray, MM AF Thackeray, MM TI Spinel electrodes for lithium batteries SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article; Proceedings Paper CT 100th Annual Meeting of the American-Ceramic-Society CY MAY 03-06, 1998 CL CINCINNATI, OHIO SP Amer Ceram Soc ID DIMENSIONAL MANGANESE OXIDE; ION BATTERIES; ORTHORHOMBIC LIMNO2; CAPACITY LOSSES; NONAQUEOUS CELL; LAYERED LIMNO2; INSERTION; DIOXIDE; SYSTEM; ELECTROCHEMISTRY AB This article gives a historical account of the development of spinel electrodes for rechargeable lithium batteries. Research in the late 1970s and early 1980s on high-temperature Li/Fe3O4 cells led to the evaluation of lithium spinels Li[B-2]X-4 at room temperature (B = metal cation). This work highlighted the importance of the [B-2]X-4 spinel framework as a host electrode structure and the ability to tailor the cell voltage by selection of various B cations. Examples of lithium-ion cells that operate with spinel anode/spinel cathode couples are provided. Particular attention is given to spinels within the solid-solution system Li1+xMn2-xO4 (0 less than or equal to x less than or equal to 0.33). C1 Argonne Natl Lab, Electrochem Technol Program, Div Chem Technol, Argonne, IL 60439 USA. RP Thackeray, MM (reprint author), Argonne Natl Lab, Electrochem Technol Program, Div Chem Technol, Argonne, IL 60439 USA. NR 59 TC 119 Z9 124 U1 6 U2 52 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD DEC PY 1999 VL 82 IS 12 BP 3347 EP 3354 PG 8 WC Materials Science, Ceramics SC Materials Science GA 291XD UT WOS:000085763900011 ER PT J AU Gritsyna, VT Afanasyev-Charkin, IV Kobyakov, VA Sickafus, KE AF Gritsyna, VT Afanasyev-Charkin, IV Kobyakov, VA Sickafus, KE TI Structure and electronic states of defects in spinel of different compositions MgO center dot nAl(2)O(3): Me SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article; Proceedings Paper CT 100th Annual Meeting of the American-Ceramic-Society CY MAY 03-06, 1998 CL CINCINNATI, OHIO SP Amer Ceram Soc ID MAGNESIUM-ALUMINUM SPINEL; VACANCY DISTRIBUTION; MGAL2O4 SPINEL; OPTICAL-SPECTRA; LUMINESCENCE; TRANSITION; RADIATION; CRYSTALS; CATION; ORDER AB This paper reviews the nature of defects and optical centers in magnesium aluminate spinel. The identification of absorption and luminescence bands was used to investigate the influence of UV and electron irradiation on optical center formation. Crystals examined were nominally pure MgO-nAl(2)O(3) crystals with compositions in the series n=1.0, 1.5, 2.0, and 2.5, MgO . Al2O3 crystals doped with transition-metal ion dopants were also studied to determine the influence of impurities on the nature and concentration of lattice defects in spinel. Results strongly suggest that absorption bands at 3.78 and 4.15 eV, and luminescence bands near 5 eV, may be attributed to optical centers on antisite defects. It is also apparent that through the introduction of specific amounts of Mn and Cr ions, the concentration of optical centers (which are related to defects such as cation antisites in the spinel structure) can be considerably changed. C1 Kharkov State Univ, Dept Phys & Technol, UA-310077 Kharkov, Ukraine. Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Gritsyna, VT (reprint author), Kharkov State Univ, Dept Phys & Technol, UA-310077 Kharkov, Ukraine. NR 38 TC 26 Z9 26 U1 0 U2 4 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD DEC PY 1999 VL 82 IS 12 BP 3365 EP 3373 PG 9 WC Materials Science, Ceramics SC Materials Science GA 291XD UT WOS:000085763900013 ER PT J AU O'Brien, MJ Sheldon, BW AF O'Brien, MJ Sheldon, BW TI Porous alumina coating with tailored fracture resistance for alumina composites SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article; Proceedings Paper CT 98th Annual Meeting of the American-Ceramic-Society CY APR 14-17, 1996 CL INDIANAPOLIS, INDIANA SP Amer Ceram Soc ID BRITTLE-MATRIX COMPOSITES; BIMATERIAL INTERFACES; CERAMIC COMPOSITES; BEHAVIOR; TOUGHNESS; MECHANICS; SPECIMENS AB A porous Al2O3 coating for Al2O3 composites was prepared by aerosol-spray deposition of submicrometer-sized Al2O3 powder. A model composite specimen was hot-pressed to change the coating's porosity and, thereby, change the interphase fracture resistance. The mixed-mode fracture resistance of the interphase ranged from 0.5 to 14.8 J/m(2). The interphase fracture was characterized using electron and acoustic microscopy, Finite-element analysis (FEA) showed that the testing method possessed a short transient behavior and was immune to asymmetrical cracks. This approach provided a fundamental investigation of the relationships among interphase microstructure, processing, and fracture resistance, The results also provided a detailed test of the He-Hutchinson criterion for crack deflection. C1 Brown Univ, Div Engn, Providence, RI 02912 USA. RP O'Brien, MJ (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 37 TC 7 Z9 7 U1 0 U2 1 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD DEC PY 1999 VL 82 IS 12 BP 3567 EP 3574 PG 8 WC Materials Science, Ceramics SC Materials Science GA 291XD UT WOS:000085763900041 ER PT J AU Wereszczak, AA Scheidt, RA Ferber, MK Breder, K AF Wereszczak, AA Scheidt, RA Ferber, MK Breder, K TI Probabilistic thermal-shock strength testing using infrared imaging SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID STRESS RESISTANCE; HEAT-TRANSFER; CERAMICS; RELIABILITY; FRACTURE AB A thermal-shock strength-testing technique has been developed that uses a high-resolution, high-temperature infrared camera to capture a specimen's surface temperature distribution at fracture. Aluminum nitride (AIN) substrates are thermally shocked to fracture to demonstrate the technique. The surface temperature distribution for each test and AIN's thermal expansion are used as input in a finite-element model to determine the thermal-shock strength for each specimen. An uncensored thermal-shock strength Weibull distribution is then determined. The test and analysis algorithm show promise as a means to characterize thermal shock strength of ceramic materials. C1 Oak Ridge Natl Lab, High Temp Mat Lab, Mech Characterizat & Anal Grp, Oak Ridge, TN 37831 USA. Univ Missouri, Rolla, MO 65401 USA. RP Oak Ridge Natl Lab, High Temp Mat Lab, Mech Characterizat & Anal Grp, Oak Ridge, TN 37831 USA. RI Wereszczak, Andrew/I-7310-2016 OI Wereszczak, Andrew/0000-0002-8344-092X NR 19 TC 3 Z9 3 U1 0 U2 1 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0002-7820 EI 1551-2916 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD DEC PY 1999 VL 82 IS 12 BP 3605 EP 3608 PG 4 WC Materials Science, Ceramics SC Materials Science GA 291XD UT WOS:000085763900046 ER PT J AU Sohlberg, K Pennycook, SJ Pantelides, ST AF Sohlberg, K Pennycook, SJ Pantelides, ST TI Explanation of the observed dearth of three-coordinated Al on gamma-alumina surfaces SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID MOLECULAR-DYNAMICS; TOTAL-ENERGY; GAMMA-AL2O3; MODELS; SITES; ATOMS AB NMR data have revealed that gamma-alumina surfaces do not contain any three-coordinated Al atoms, despite the fact that their presence is expected on the basis of the bulk structure of the material. We report density-functional calculations of gamma-alumina (110) surfaces that reveal a massive spontaneous reconstruction of the ideally terminated bulk. The three-coordinated Al atoms initially in the surface layer drop into vacant octahedral interstices in the second layer where they become six-coordinated. The predicted reconstruction is also fully consistent with IR studies of hydroxylated gamma-alumina surfaces and reveals the physical origin of results obtained by earlier computational simulations. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. RP Sohlberg, K (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. NR 24 TC 51 Z9 53 U1 2 U2 18 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 DEC 1 PY 1999 VL 121 IS 47 BP 10999 EP 11001 DI 10.1021/ja9926358 PG 3 WC Chemistry, Multidisciplinary SC Chemistry GA 263ZH UT WOS:000084154800019 ER PT J AU Jones, G Yan, DX Gosztola, DJ Greenfield, SR Wasielewski, MR AF Jones, G Yan, DX Gosztola, DJ Greenfield, SR Wasielewski, MR TI Photoinduced charge migration in the picosecond regime for thianthrene-linked acridinium ions SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID INTRAMOLECULAR ELECTRON-TRANSFER; MARCUS INVERTED REGION; CATION RADICALS; SEPARATION; MOLECULES; DISTANCE; SYSTEMS C1 Boston Univ, Dept Chem, Boston, MA 02215 USA. Boston Univ, Photon Ctr, Boston, MA 02215 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Northwestern Univ, Dept Chem, Evanston, IL 60208 USA. RP Jones, G (reprint author), Boston Univ, Dept Chem, 590 Commonwealth Ave, Boston, MA 02215 USA. RI Gosztola, David/D-9320-2011 OI Gosztola, David/0000-0003-2674-1379 NR 27 TC 11 Z9 11 U1 0 U2 4 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 DEC 1 PY 1999 VL 121 IS 47 BP 11016 EP 11017 DI 10.1021/ja9927319 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 263ZH UT WOS:000084154800027 ER PT J AU Meyer, JL Sale, MJ Mulholland, PJ Poff, NL AF Meyer, JL Sale, MJ Mulholland, PJ Poff, NL TI Impacts of climate change on aquatic ecosystem functioning and health SO JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION LA English DT Review DE aquatic ecosystems; anthropogenic change; climate change; instream flow; riparian zones; surface water hydrology; water quality; water temperature ID FRESH-WATER ECOSYSTEMS; NEW-ZEALAND STREAMS; NORTH-AMERICA; UNITED-STATES; HYPORHEIC ZONE; GREAT-LAKES; COMMUNITY STRUCTURE; HABITAT TEMPLATE; FLOW VARIABILITY; WOODLAND STREAM AB We review published analyses of the effects of climate change on goods and services provided by freshwater ecosystems in the United States. Climate-induced changes must be assessed in the context of massive anthropogenic changes in water quantity and quality resulting from altered patterns of land use, water withdrawal, and species invasions; these may dwarf or exacerbate climate-induced changes. Water to meet instream needs is competing with other uses of water, and that competition is likely to be increased by climate change. We review recent predictions of the impacts of climate change on aquatic ecosystems in eight regions of North America. Impacts include warmer temperatures that alter lake mixing regimes and availability of fish habitat; changed magnitude and seasonality of runoff regimes that alter nutrient loading and limit habitat availability at low flow; and loss of prairie pothole wetlands that reduces waterfowl populations. Many of the predicted changes in aquatic ecosystems are a consequence of climatic effects on terrestrial ecosystems; shifts in riparian vegetation and hydrology are particularly critical. We review models that could be used to explore potential effects of climate change on freshwater ecosystems; these include models of instream flow, bioenergetics models, nutrient spiraling models, and models relating riverine food webs to hydrologic regime. We discuss potential ecological risks, benefits, and costs of climate change and identify information needs and model improvements that are required to improve our ability to predict and identify climate change impacts and to evaluate management options. C1 Univ Georgia, Inst Ecol, Athens, GA 30602 USA. Oak Ridge Natl Lab, Div Environm Sci, Res Staff, Oak Ridge, TN 37830 USA. Colorado State Univ, Dept Biol, Ft Collins, CO 80523 USA. RP Meyer, JL (reprint author), Univ Georgia, Inst Ecol, Athens, GA 30602 USA. RI Poff, Nathan/C-1239-2009; Mulholland, Patrick/C-3142-2012 NR 113 TC 141 Z9 146 U1 29 U2 190 PU AMER WATER RESOURCES ASSOC PI HERNDON PA 950 HERNDON PARKWAY SUITE 300, HERNDON, VA 20170-5531 USA SN 1093-474X J9 J AM WATER RESOUR AS JI J. Am. Water Resour. Assoc. PD DEC PY 1999 VL 35 IS 6 BP 1373 EP 1386 DI 10.1111/j.1752-1688.1999.tb04222.x PG 14 WC Engineering, Environmental; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA 271ZB UT WOS:000084624600008 ER PT J AU Leung, LR Wigmosta, MS AF Leung, LR Wigmosta, MS TI Potential climate chance impacts on mountain watersheds in the Pacific Northwest SO JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION LA English DT Article DE surface water hydrology; climate change impacts; dynamical downscaling; mountain water resources; snowpack; distributed hydrologic modeling; water resources planning ID OROGRAPHIC PRECIPITATION; ATMOSPHERIC CO2; MODEL AB Global climate change due to the buildup of greenhouse gases in the atmosphere has serious potential impacts on water resources in the Pacific Northwest. Climate scenarios produced by general circulation models (GCMs) do not provide enough spatial specificity for studying water resources in mountain watersheds. This study uses dynamical downscaling with a regional climate model (RCM) driven by a GCM to simulate climate change scenarios. The RCM uses a subgrid parameterization of orographic precipitation and land surface cover to simulate surface climate at the spatial scale suitable for the representation of topographic effects over mountainous regions. Numerical experiments have been performed to simulate the present-day climatology and the climate conditions corresponding to a doubling of atmospheric CO2 concentration. The RCM results indicate an average warming of about 2.5 degrees C, and precipitation generally increases over the Pacific Northwest and decreases over California. These simulations were used to drive a distributed hydrology model of two snow dominated watersheds, the American River and Middle Fork Flathead, in the Pacific Northwest to obtain more detailed estimates of the sensitivity of water resources to climate change. Results show that as more precipitation falls as rain rather than snow in the warmer climate, there is a 60 percent reduction in snowpack and a significant shift in the seasonal pattern of streamflow in the American River. Much less drastic changes are found in the Middle Fork Flathead where snowpack is only reduced by 18 percent and the seasonal pattern of streamflow remains intact. This study shows that the impacts of climate change on water resources are highly region specific. Furthermore, under the specific climate change scenario, the impacts are largely driven by the warming trend rather than the precipitation trend, which is small. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Leung, LR (reprint author), Pacific NW Natl Lab, POB 999, Richland, WA 99352 USA. NR 19 TC 55 Z9 56 U1 1 U2 15 PU AMER WATER RESOURCES ASSOC PI HERNDON PA 950 HERNDON PARKWAY SUITE 300, HERNDON, VA 20170-5531 USA SN 1093-474X J9 J AM WATER RESOUR AS JI J. Am. Water Resour. Assoc. PD DEC PY 1999 VL 35 IS 6 BP 1463 EP 1471 DI 10.1111/j.1752-1688.1999.tb04230.x PG 9 WC Engineering, Environmental; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA 271ZB UT WOS:000084624600016 ER PT J AU Miller, NL Kim, J Hartman, RK Farrara, J AF Miller, NL Kim, J Hartman, RK Farrara, J TI Downscaled climate and streamflow study of the southwestern United States SO JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION LA English DT Article DE meteorology/climatology; modeling/statistics/surface water hydrology; water management; water resources planning ID STOCHASTIC HYDROMETEOROLOGICAL MODEL; PRECIPITATION; SIMULATION; CALIFORNIA; TOPMODEL; BUDGET; FLOOD AB Downscaling coarse resolution climate data to scales that are useful for impact assessment studies is receiving increased attention. Basin-scale hydrologic processes and other local climate impacts related to water resources such as reservoir management, crop and forest productivity, and ecosystem response require climate information at scales that are much finer than current and future GCM resolutions. The Regional Climate System Model (RCSM) is a dynamic downscaling system that has been used since 1994 for short-term precipitation and streamflow predictions and seasonal hindcast analysis with good skill. During the 1997-1998 winter, experimental seasonal forecasts were made in collaboration with the NOAA Climate Prediction Center and UCLA with promising results. Preliminary studies of a control and 2xCO(2) perturbation for the southwestern U.S. have been performed. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Reg Climate Ctr, Berkeley, CA 94720 USA. Calif Nevada River Forecast Ctr, Sacramento, CA 95821 USA. Univ Calif Los Angeles, Dept Atmospher Sci, Los Angeles, CA 90095 USA. RP Miller, NL (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Reg Climate Ctr, 90-1116,1 Cyclotron Rd, Berkeley, CA 94720 USA. EM nlmiller@lbl.gov RI Miller, Norman/E-6897-2010 NR 20 TC 35 Z9 37 U1 1 U2 7 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1093-474X J9 J AM WATER RESOUR AS JI J. Am. Water Resour. Assoc. PD DEC PY 1999 VL 35 IS 6 BP 1525 EP 1537 DI 10.1111/j.1752-1688.1999.tb04235.x PG 13 WC Engineering, Environmental; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA 271ZB UT WOS:000084624600021 ER PT J AU Nolan, DS Farrell, BF AF Nolan, DS Farrell, BF TI The intensification of two-dimensional swirling flows by stochastic asymmetric forcing SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID QUASI-GEOSTROPHIC MODEL; WATER BAROTROPIC VORTEX; ROSSBY-WAVES; SPIRAL BANDS; SIMULATED TORNADOES; VORTICES; MOTION; AXISYMMETRIZATION; HURRICANES; STABILITY AB The effects of stochastically excited asymmetric disturbances on two-dimensional vortices are investigated. These vortices are maintained by the radial inflow of fixed cylindrical deformation fields, which are chosen so that both one-celled and two-celled vortices may be studied. The linearized perturbation equations are reduced to the form of a linear dynamical system with stochastic forcing, that is, dx/dt = Ax + F xi, where the columns of F are forcing functions and the elements of xi are Gaussian white-noise processes Through this formulation the stochasrically maintained variance of the perturbations, the structures that dominate the response (the empirical orthogonal functions), and the forcing functions that contribute most to this response (the stochastic optimals) can be directly calculated. For ail cases the structures that most effectively induce the transfer of energy from the mean flow to the perturbation field are close approximations to the global optimals (i.e., the initial perturbations with the maximum growth in energy in finite rime), and that the structures that account for most of the variance are close approximations to the global optimals evolved forward in time to when they reach their maximum energy. For azimuthal wavenumbers in each vortex where nearly neutral modes are present (k = 1 for the one-celled vortex and 1 k less than or equal to 4 for the two-celled vortex), the variance sustained by the stochastic forcing is large, and in these cases the variance may be greatly overestimated if the radial inflow that sustains the mean vortex is neglected in the dynamics of the perturbations. Through a modification of this technique the ensemble average eddy momentum Aux divergences associated with the stochastically maintained perturbation fields can be computed, and this information is used to determine the perturbation-induced mean how tendency in the linear limit. Examination of these results shows that the net effect of the low wavenumber perturbations is to cause downgradient eddy fluxes in both vortex types, while high wavenumber perturbations cause upgradient eddy fluxes. However, to determine how these eddy fluxes actually change the mean flow, the local accelerations caused by the eddy flux divergences must be incorporated into the equation for the steady-state azimuthal velocity. From calculations of this type, it is found that the effect of the radial inflow can be crucial in determining whether or not the vortex is intensified or weakened by the perturbations: though the net eddy fluxes are most often downgradient, the radial inflow carries the transported angular momentum back into the vortex core, resulting in an increase in the maximum wind speed. In most cases for the vortex flows studied, the net effect of stochastically forced asymmetric perturbations is to intensify the mean vortex. Applications of the same analysis techniques to vortices with azimuthal velocity profiles more like those used in previous studies give similar results. C1 Lawrence Berkeley 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 55 TC 29 Z9 29 U1 0 U2 1 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 DEC 1 PY 1999 VL 56 IS 23 BP 3937 EP 3962 DI 10.1175/1520-0469(1999)056<3937:TIOTDS>2.0.CO;2 PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 259HT UT WOS:000083889000001 ER PT J AU Striebel, KA Rougier, A Horne, CR Reade, RP Cairns, EJ AF Striebel, KA Rougier, A Horne, CR Reade, RP Cairns, EJ TI Electrochemical studies of substituted spinel thin films SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID RECHARGEABLE LITHIUM BATTERIES; MANGANESE-OXIDE; LIMN2O4; SYSTEM; INSERTION; CELLS; SPECTROSCOPY; ELECTRODES; DIFFUSION; BEHAVIOR AB Thin lithium manganese oxide spinel films, prepared with pulsed laser deposition have been used as a model system for the study of oxide electrochemical properties and performance degradation mechanisms in the absence of carbon or binder materials. Films (0.3 mu m) of LixMn2-yMeyO4, where Me = Ni, Co and y = 0, 0.1, 0.25, were crystalline as-prepared. The cyclic voltammetric response as a function of oxide composition was measured in liquid electrolyte over the range of 2 to 5.8 V vs. Li/Li+. Quantitative analysis of the two 4 V peaks, for x > 0.5 and x < 0.5, correlated well with predicted film stoichiometry. The capacity of the 4.6 V redox peaks in the Ni-substituted films were consistent with the oxidation of Ni2+ to Ni4+. No significant capacity was observed in LiMn2O4 above 4.5 V. The shape of the voltammetric peaks in the 3 V region suggested that intercalation kinetics are slowed by the Jahn-Teller distortion, while all compositions in the 4 V region showed reversible behavior, except for the LiNi0.25Mn1.75O4 film which showed lower electronic conductivity. The LiMn1.90Ni0.10O4 films showed no loss in discharge capacity after being charged up to 5.7 V vs. Li/Li+ with window-opening cyclic voltammetry. LiMn2O4 and LiMn1.75Co0.25O4 films were stable to 5.6 and 5.4 V vs. Li/Li+, respectively. Explanations for the superior stability of the films relative to powder electrodes are examined. (C) 1999 The Electrochemical Society. S0013-4651(99)04-040-9. All rights reserved. C1 Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. RP Striebel, KA (reprint author), Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. RI Cairns, Elton/E-8873-2012 OI Cairns, Elton/0000-0002-1179-7591 NR 37 TC 64 Z9 67 U1 0 U2 14 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 65 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD DEC PY 1999 VL 146 IS 12 BP 4339 EP 4347 DI 10.1149/1.1392640 PG 9 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 265PE UT WOS:000084251900002 ER PT J AU Thomas, SC Ren, X Gottesfeld, S AF Thomas, SC Ren, X Gottesfeld, S TI Influence of ionomer content in catalyst layers on direct methanol fuel cell performance SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID ELECTRODES; MICROSTRUCTURE; CARBON AB The ionomer content in catalyst layers has a marked influence on direct methanol fuel cell (DMFC) performance. In an anode which contains unsupported PtRu as the catalyst, the recast ionomer may not always be necessary because the protonic conductivity of hydrous RuOx, the presence of which is inferred from the X-ray diffraction pattern, may be sufficient to allow effective utilization of catalyst sites. To examine interpenetration of catalyst and membrane material as a possible explanation for the lack of an apparent need of added ionomer, ultramicrotomed thin sections of the membrane-electrode assembly (MEA) were examined by scanning electron microscopy. Microscopic examination of such MEA cross sections revealed significant porosity in layers made by mixing unsupported catalysts with recast ionomer Images of such sections did not reveal significant interpenetration, supporting the interpretation that hydrous RuOx may by itself provide sufficient protonic conductivity in PtRu catalyst layers prepared with no added ionomer. In contrast we: show that the presence of recast ionomer in DMFC cathodes based on unsupported Pt as the catalyst is essential for optimum DMFC performance, because the recast ionomer is the primary source of protonic conductivity in the latter case. Having shown its potential function as proton conductor, we stress that Ru oxide is apparently not the key for maximizing DMFC anodic activity. (C) 1999 The Electrochemical Society. S0013-4651(99)05-024-7. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Thomas, SC (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI ren, xiaoming/F-3953-2011 NR 16 TC 121 Z9 124 U1 6 U2 14 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 65 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD DEC PY 1999 VL 146 IS 12 BP 4354 EP 4359 DI 10.1149/1.1392642 PG 6 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 265PE UT WOS:000084251900004 ER PT J AU Buchheit, RG Montes, LP Martinez, MA Michael, J Hlava, PF AF Buchheit, RG Montes, LP Martinez, MA Michael, J Hlava, PF TI The electrochemical characteristics of bulk-synthesized Al2CuMg SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID ALLOYS; PHASE; CORROSION AB An S-phase intermetallic compound (Al2CuMg) was synthesized in bulk form to characterize its, electrochemical behavior by conventional techniques. Large S-phase crystals, suitable for analysis, were formed in an Al-Cu-Mg ingot. The structure of Al2CuMg was verified by electron-backscatter Kikuchi patterns and X-ray diffraction. The composition of Al2CuMg was verified by electron-probe microchemical analysis. Open-circuit potential and potentiodynamic polarization measurements were conducted in aerated and deaerated 0.5 M NaCl solutions. Bulk S-phase electrodes exhibited steady-state open-circuit potentials ranging from -0.920 to -0.930 V-SCE, which did not vary significantly with changes in solution aeration. In aerated solutions, the phase dissolved vigorously at modest anodic polarizations, and no passive response was detected. Limiting cathodic current densities on the order of 1.0 mA/cm(2) were measured for small cathodic polarizations, probably due to the development of a porous, catalytic surface. Overall, the S phase supports rapid anodic and cathodic reaction kinetics, which contribute to the instability of the compound and subsequent Liberation of Cu. These results implicate the presence of S-phase intermetallic particles as a key contributor to the poor corrosion resistance of Al-Cu-Mg alloys. (C) 1999 The Electrochemical Society. S0013-4651(99)01-011-3, All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Buchheit, RG (reprint author), Ohio State Univ, Dept Mat Sci & Engn, Columbus, OH 43210 USA. NR 16 TC 100 Z9 100 U1 2 U2 17 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 65 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD DEC PY 1999 VL 146 IS 12 BP 4424 EP 4428 DI 10.1149/1.1392654 PG 5 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 265PE UT WOS:000084251900016 ER EF