FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Zhong, JX Wang, EG Niu, Q Zhang, ZY AF Zhong, JX Wang, EG Niu, Q Zhang, ZY TI Morphological symmetry breaking during epitaxial growth at grazing incidence SO PHYSICAL REVIEW LETTERS LA English DT Article ID SURFACES AB It is shown that, in submonolayer growth at off-normal incidence, even much less than 1% of transfer from the condensation energy of the deposited atoms into adatom motion is sufficient to induce a net adatom current from the illuminated edge of a two-dimensional island to the other edges, thereby breaking the island symmetry. Such a symmetry breaking phenomenon is most pronounced for deposition at grazing incidence. Comparison between our theoretical predictions and existing experimental results confirms the general validity of the model. C1 Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Chinese Acad Sci, Inst Phys, Beijing 100080, Peoples R China. Chinese Acad Sci, Ctr Condensed Matter Phys, Beijing 100080, Peoples R China. Univ Texas, Dept Phys, Austin, TX 78712 USA. RP Zhong, JX (reprint author), Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. RI Niu, Qian/G-9908-2013 NR 19 TC 10 Z9 11 U1 1 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 APR 24 PY 2000 VL 84 IS 17 BP 3895 EP 3898 DI 10.1103/PhysRevLett.84.3895 PG 4 WC Physics, Multidisciplinary SC Physics GA 307CM UT WOS:000086635900041 ER PT J AU Caliebe, WA Soininen, JA Shirley, EL Kao, CC Hamalainen, K AF Caliebe, WA Soininen, JA Shirley, EL Kao, CC Hamalainen, K TI Dynamic structure factor of diamond and LiF measured using inelastic X-ray scattering SO PHYSICAL REVIEW LETTERS LA English DT Article ID AB-INITIO CALCULATION; PLASMON DISPERSION; BAND-STRUCTURE; ELECTRONS; METAL; RESOLUTION; SEMICONDUCTORS; SPECTROMETER; INSULATORS; AL AB The dynamic structure factors S((q) over right arrow, omega) of diamond and LiF have been measured using inelastic x-ray scattering. The experimental data are compared to results of ab initio calculations, which take into account the interaction of the excited electron with the remaining hole. In diamond, the vicinity of the indirect band gap and its momentum dependence are studied. In LiF, a larger energy range, which covers the fundamental exciton, the plasmon, and several interband transitions, is investigated. Calculations and measurements agree quite well and emphasize the need to properly include the interaction of the excited electron in the conduction band with the hole in the valence band. C1 Forschungszentrum, Inst Festkorperforsch, D-52425 Julich, Germany. Natl Inst Stand & Technol, Opt Technol Div, Phys Lab, Gaithersburg, MD 20899 USA. Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. Univ Helsinki, Dept Phys, FIN-00014 Helsinki, Finland. RP Forschungszentrum, Inst Festkorperforsch, D-52425 Julich, Germany. RI Hamalainen, Keijo/A-3986-2010 OI Hamalainen, Keijo/0000-0002-9234-9810 NR 30 TC 43 Z9 43 U1 1 U2 8 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 APR 24 PY 2000 VL 84 IS 17 BP 3907 EP 3910 DI 10.1103/PhysRevLett.84.3907 PG 4 WC Physics, Multidisciplinary SC Physics GA 307CM UT WOS:000086635900044 ER PT J AU Pashkevich, YG Blinkin, VA Gnezdilov, VP Tsapenko, VV Eremenko, VV Lemmens, P Fischer, M Grove, M Guntherodt, G Degiorgi, L Wachter, P Tranquada, JM Buttrey, DJ AF Pashkevich, YG Blinkin, VA Gnezdilov, VP Tsapenko, VV Eremenko, VV Lemmens, P Fischer, M Grove, M Guntherodt, G Degiorgi, L Wachter, P Tranquada, JM Buttrey, DJ TI Stripe conductivity in La1.775Sr0.225NiO4 SO PHYSICAL REVIEW LETTERS LA English DT Article ID STRUCTURAL PHASE-TRANSITION; X-RAY DIFFRACTION; CHARGE; ORDER; LA2NIO4; LA1.67SR0.33NIO4; LA2-XSRXNIO4; SCATTERING; LATTICE; SPINS AB We report Raman light-scattering and optical conductivity measurements on a single crystal of La1.775Sr0.225NiO4 which exhibits incommensurate charge-stripe order. The extra phonon peaks induced by stripe order can be understood in terms of the energies of phonons that occur at the charge-order wave vector Q(c). A strong Fano antiresonance for a Ni-O bond-stretching mode provides clear evidence for finite dynamical conductivity within the charge stripes. C1 NASU, AA Galkin Donetsk Phystech, UA-83114 Donetsk, Ukraine. NASU, Inst Single Crystals, UA-310001 Kharkov, Ukraine. NASU, BI Verkin Inst Low Temp Phys, UA-310164 Kharkov, Ukraine. Rhein Westfal TH Aachen, Inst Phys, D-52056 Aachen, Germany. ETH Zurich, Festkorperphys Lab, CH-8093 Zurich, Switzerland. Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Delaware, Newark, DE 19716 USA. RP Pashkevich, YG (reprint author), NASU, AA Galkin Donetsk Phystech, UA-83114 Donetsk, Ukraine. RI Tranquada, John/A-9832-2009; Lemmens, Peter /C-8398-2009 OI Tranquada, John/0000-0003-4984-8857; Lemmens, Peter /0000-0002-0894-3412 NR 27 TC 28 Z9 28 U1 0 U2 9 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 APR 24 PY 2000 VL 84 IS 17 BP 3919 EP 3922 DI 10.1103/PhysRevLett.84.3919 PG 4 WC Physics, Multidisciplinary SC Physics GA 307CM UT WOS:000086635900047 ER PT J AU Bao, W McQueeney, RJ Heffner, R Sarrao, JL Dai, P Zarestky, JL AF Bao, W McQueeney, RJ Heffner, R Sarrao, JL Dai, P Zarestky, JL TI Commensurate dynamic magnetic correlations in La2Cu0.9Li0.1O4 SO PHYSICAL REVIEW LETTERS LA English DT Article ID T-J MODEL; 2-DIMENSIONAL HUBBARD-MODEL; SPIN FLUCTUATIONS; NEUTRON-SCATTERING; PHASE-SEPARATION; SUPERCONDUCTING LA2-XSRXCUO4; QUANTUM ANTIFERROMAGNET; CHARGE-TRANSFER; CUO2 PLANES; EXCITATIONS AB When sufficient numbers of holes are introduced into the two-dimensional CuO2 square lattice, dynamic magnetic correlations become incommensurate with underlying lattice in all previously investigated La(2-x)A(x)Cu(1-z)B(z)O(4+y) (A = Sr or Nd, B = Zn) including high T-c superconductors and insulators, and in bilayered superconducting YBa2Cu3O6.6 and Bi2Sr2CaCu2O8. Magnetic correlations also become incommensurate in structurally related La2NiO4 when doped with Sr or O. We report an exception to this so-far well-established experimental "rule" in La2Cu1-zLizO4 in which magnetic correlations remain commensurate. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Ames Lab, Ames, IA 50011 USA. RP Bao, W (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Bao, Wei/E-9988-2011; Dai, Pengcheng /C-9171-2012; McQueeney, Robert/A-2864-2016 OI Bao, Wei/0000-0002-2105-461X; Dai, Pengcheng /0000-0002-6088-3170; McQueeney, Robert/0000-0003-0718-5602 NR 53 TC 10 Z9 10 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 APR 24 PY 2000 VL 84 IS 17 BP 3978 EP 3981 DI 10.1103/PhysRevLett.84.3978 PG 4 WC Physics, Multidisciplinary SC Physics GA 307CM UT WOS:000086635900062 ER PT J AU Fitzsimmons, MR Yashar, P Leighton, C Schuller, IK Nogues, J Majkrzak, CF Dura, JA AF Fitzsimmons, MR Yashar, P Leighton, C Schuller, IK Nogues, J Majkrzak, CF Dura, JA TI Asymmetric magnetization reversal in exchange-biased hysteresis loops SO PHYSICAL REVIEW LETTERS LA English DT Article ID FEF2-FE BILAYERS; THIN-FILMS; INTERFACES; ANISOTROPY; SYSTEMS AB Polarized neutron reflectometry is used to probe the in-plane projection of the net-magnetization Vector (M) over bar of polycrystalline Fe films exchange coupled to twinned (110) MnF2 or FeF2 antiferromagnetic (AF) layers. The magnetization reversal mechanism depends upon the orientation of the cooling field with respect to the twinned microstructure of the AF, and whether the applied field is increased to (or decreased from) a positive saturating field; i.e., the magnetization reversal is asymmetric. The reversal of the sample magnetization from one saturated state to the other occurs via either domain wall motion or magnetization rotation on opposite sides of the same hysteresis loop. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. Univ Autonoma Barcelona, Dept Fis, Bellaterra 08193, Spain. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Fitzsimmons, MR (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Dura, Joseph/B-8452-2008; Nogues, Josep/D-7791-2012; Lujan Center, LANL/G-4896-2012 OI Dura, Joseph/0000-0001-6877-959X; Nogues, Josep/0000-0003-4616-1371; NR 25 TC 273 Z9 274 U1 7 U2 63 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 APR 24 PY 2000 VL 84 IS 17 BP 3986 EP 3989 DI 10.1103/PhysRevLett.84.3986 PG 4 WC Physics, Multidisciplinary SC Physics GA 307CM UT WOS:000086635900064 ER PT J AU Strasburg, S Davidson, RC AF Strasburg, S Davidson, RC TI Macroscopic description of pressure-anisotropy-driven collective instability in intense charged particle beams SO PHYSICS LETTERS A LA English DT Article ID STABILITY; EQUILIBRIUM; FIELD; PROPAGATION AB The macroscopic warm-fluid model developed by Lund and Davidson [Phys. plasmas 5 (1998) 3028] is used in the smooth-focusing approximation to investigate detailed stability properties of an intense charged particle beam with pressure anisotropy, assuming small-amplitude electrostatic perturbations about a waterbag equilibrium. Stability properties are calculated numerically for the case of extreme pressure anisotropy with P-II(0)( r)= 0 and P-perpendicular to(0) (r) not equal 0, assuming axisymmetric wave perturbations (partial derivative/partial derivative theta = 0) of the form delta phi(x,t)= delta phi(r)exp(ik, z - iwt), where k(z) is the axial wavenumber, and Im omega > 0 corresponds to instability (temporal growth). For sufficiently large values of k(z)r(b) where r(b) is the beam radius, the analysis leads to an anistropy-driven instability (Im omega > 0) provided the normalized Debye length (Gamma(D) = lambda(D perpendicular to)/(r)b) is sufficiently large and the normalized beam intensity (s(b) = <(omega)over cap>(2)(pb)/2 gamma(b)(2)omega(beta)(perpendicular to)(2)) is sufficiently below the space-charge limit. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Princeton Univ, Plasma Phys Lab, Princeton, NJ 08543 USA. RP Davidson, RC (reprint author), Princeton Univ, Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 23 TC 4 Z9 4 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 APR 24 PY 2000 VL 269 IS 1 BP 40 EP 49 DI 10.1016/S0375-9601(00)00208-5 PG 10 WC Physics, Multidisciplinary SC Physics GA 309GB UT WOS:000086759000005 ER PT J AU Abdelouas, A Lutze, W Gong, WL Nuttall, EH Strietelmeier, BA Travis, BJ AF Abdelouas, A Lutze, W Gong, WL Nuttall, EH Strietelmeier, BA Travis, BJ TI Biological reduction of uranium in groundwater and subsurface soil SO SCIENCE OF THE TOTAL ENVIRONMENT LA English DT Article DE uranium; bioremediation; groundwater; uraninite; iron sulfide; indigenous bacteria; speciation; redox buffer ID SULFATE-REDUCING BACTERIA; NATURAL FISSION REACTORS; IN-SITU IMMOBILIZATION; DESULFOVIBRIO-DESULFURICANS; ORE-DEPOSITS; WATER; BIOREMEDIATION; MICROORGANISMS; GEOCHEMISTRY; URANINITE AB Biological reduction of uranium is one of the techniques currently studied for in situ remediation of groundwater and subsurface soil. We investigated U(VI) reduction in groundwaters and soils of different origin to verify the presence of bacteria capable of U(VI) reduction. The groundwaters originated from mill tailings sites with U concentrations as high as 50 mg/l, and from other sites where uranium is not a contaminant, but was added in the laboratory to reach concentrations up to 11 mg/l. All waters contained nitrate and sulfate. After oxygen and nitrate reduction, U(VI) was reduced by sulfate-reducing bacteria, whose growth was stimulated by ethanol and trimetaphosphate. Uranium precipitated as hydrated uraninite (UO2. xH(2)O). In the course of reduction of U(VI), Mn(IV)and Fe(III) from the soil were reduced as well. During uraninite precipitation a comparatively large mass of iron sulfides formed and served as a redox buffer. If the excess of iron sulfide is large enough, uraninite will not be oxidized by oxygenated groundwater. We show that bacteria capable of reducing U(VI) to U(IV) are ubiquitous in nature. The uranium reducers are primarily sulfate reducers and are stimulated by adding nutrients to the groundwater. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Adv Mat Lab, Ctr Radioact Waste Management, Albuquerque, NM 87106 USA. Univ New Mexico, Dept Chem & Nucl Engn, Albuquerque, NM 87131 USA. Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87544 USA. Univ Calif Los Alamos Natl Lab, Div Earth & Environm Sci, Los Alamos, NM 87544 USA. RP Abdelouas, A (reprint author), Adv Mat Lab, Ctr Radioact Waste Management, 1001 Univ Blvd,SE Suite 201, Albuquerque, NM 87106 USA. NR 62 TC 81 Z9 86 U1 3 U2 31 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0048-9697 J9 SCI TOTAL ENVIRON JI Sci. Total Environ. PD APR 24 PY 2000 VL 250 IS 1-3 BP 21 EP 35 DI 10.1016/S0048-9697(99)00549-5 PG 15 WC Environmental Sciences SC Environmental Sciences & Ecology GA 308ZX UT WOS:000086743700003 PM 10811248 ER PT J AU Wang, XB Wang, LS AF Wang, XB Wang, LS TI Probing the electronic structure of redox species and direct determination of intrinsic reorganization energies of electron transfer reactions SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID IRON-SULFUR PROTEINS; ACTIVE-SITES; CHEMISTRY; ANIONS AB An experimental technique capable of directly determining the intrinsic reorganization energies of bimolecular electron transfer reactions is described. Appropriate solution phase redox species are prepared in the gas phase using electrospray ionization and probed using photodetachment spectroscopy. Five metal complex anions involved in the Fe(2+)-Fe(3+) redox couple are investigated and the intramolecular reorganization energies are measured directly from spectral features due to removing the most loosely bound 3d electron from the Fe(II)-complexes. The photodetachment spectra also yield electronic structure information about the Fe(2+)-Fe(3+) redox couple and provide a common electronic structure origin for the reducing capability of the Fe(II)-complexes, the most common redox reagents. (C) 2000 American Institute of Physics. [S0021- 9606(00)01216-2]. C1 Washington State Univ, Dept Phys, Richland, WA 99352 USA. Pacific NW Natl Lab, WR Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Wang, XB (reprint author), Washington State Univ, Dept Phys, 2710 Univ Dr, Richland, WA 99352 USA. EM ls.wang@pnl.gov NR 30 TC 35 Z9 35 U1 2 U2 8 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 APR 22 PY 2000 VL 112 IS 16 BP 6959 EP 6962 DI 10.1063/1.481292 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 303WU UT WOS:000086450300004 ER PT J AU Dauw, XLR van den Berg, GJB van den Heuvel, DJ Poluektov, OG Groenen, EJJ AF Dauw, XLR van den Berg, GJB van den Heuvel, DJ Poluektov, OG Groenen, EJJ TI The triplet wave function of C-60 from W-band electron nuclear double resonance spectroscopy SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID 95 GHZ; STATE; SPECTRA; FULLERENES; ENDOR; EPR; C-13(60); C60 AB Electron-nuclear double resonance spectra at 95 GHz and electron-spin-echo envelope-modulation spectra at 9.5 GHz are reported for a frozen solution of fully C-13 enriched C-60 molecules in their photoexcited triplet state. Analysis of these data reveals that the triplet wave function is largely localized on a part of the molecule. Upon excitation, the C-60 molecule adopts a structure of D-5d symmetry with four symmetry inequivalent carbon atoms. The equator atoms each carry 3.8% of the spin density and the atoms next to the equator 1.1%, together accounting for 98% of the total spin density. These pi-spin densities make the hyperfine interaction mainly anisotropic. A slight s-spin density on the equator atoms adds a sizable isotropic hyperfine coupling. The triplet wave function is calculated quantum-chemically and compared with the observed spin-density distribution. (C) 2000 American Institute of Physics. [S0021-9606(00)00716-9]. C1 Leiden Univ, Huygens Lab, Ctr Study Excited States Mol, NL-2300 RA Leiden, Netherlands. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Groenen, EJJ (reprint author), Leiden Univ, Huygens Lab, Ctr Study Excited States Mol, POB 9504, NL-2300 RA Leiden, Netherlands. NR 21 TC 16 Z9 16 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 22 PY 2000 VL 112 IS 16 BP 7102 EP 7110 DI 10.1063/1.481305 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 303WU UT WOS:000086450300023 ER PT J AU Bedrov, D Smith, GD Sewell, TD AF Bedrov, D Smith, GD Sewell, TD TI Temperature-dependent shear viscosity coefficient of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX): A molecular dynamics simulation study SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID N-ALKANES AB Equilibrium molecular dynamics methods were used in conjunction with linear response theory and a recently published potential-energy surface [J. Phys. Chem. B 103, 3570 (1999)] to compute the liquid shear viscosity and self-diffusion coefficient of the high explosive HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) over the temperature domain 550-800 K. Predicted values of the shear viscosity range from 0.0055 Pa *s at the highest temperature studied up to 0.45 Pa *s for temperatures near the melting point. The results, which represent the first publication of the shear viscosity of HMX, are found to be described by an Arrhenius rate law over the entire temperature domain studied. The apparent activation energy for the shear viscosity is found to scale with the heat of vaporization in a fashion consistent with those for a wide variety of simple nonmetallic liquids. The self-diffusion coefficient, which requires significantly shorter trajectories than the shear viscosity for accurate calculation, also exhibits an Arrhenius temperature dependence over the simulated temperature domain. This has potentially important implications for predictions of the shear viscosity at temperatures near the melting point. (C) 2000 American Institute of Physics. [S0021- 9606(00)50613-8]. C1 Univ Utah, Dept Mat Sci & Engn, Salt Lake City, UT 84112 USA. Univ Utah, Dept Chem & Fuels Engn, Salt Lake City, UT 84112 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Bedrov, D (reprint author), Univ Utah, Dept Mat Sci & Engn, 122 S Cent Campus Dr,Room 304, Salt Lake City, UT 84112 USA. NR 20 TC 56 Z9 57 U1 4 U2 19 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 22 PY 2000 VL 112 IS 16 BP 7203 EP 7208 DI 10.1063/1.481285 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 303WU UT WOS:000086450300035 ER PT J AU Altschuler, EL Hud, NV Mazrimas, JA Rupp, B AF Altschuler, EL Hud, NV Mazrimas, JA Rupp, B TI Structure of polyglutamine SO FEBS LETTERS LA English DT Letter ID PEPTIDES; CONFORMATION C1 Univ Calif San Diego, Inst Neural Computat, La Jolla, CA 92093 USA. Georgia Inst Technol, Sch Chem & Biochem, Atlanta, GA 30332 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Altschuler, EL (reprint author), Univ Calif San Diego, Inst Neural Computat, 9500 Gilman Dr,0109, La Jolla, CA 92093 USA. NR 12 TC 12 Z9 12 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 APR 21 PY 2000 VL 472 IS 1 BP 166 EP 167 DI 10.1016/S0014-5793(00)01381-8 PG 2 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 308UL UT WOS:000086731200034 PM 10781826 ER PT J AU Doornbos, J Pile, P Meot, F Aoki, M Blackmore, EW Chang, IH Kost, CJ Li, KK Macdonald, JA Nakano, T AF Doornbos, J Pile, P Meot, F Aoki, M Blackmore, EW Chang, IH Kost, CJ Li, KK Macdonald, JA Nakano, T TI Optics design and performance of LESB3, a two-stage separated 800-MeV/c kaon beamline SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE brookhaven AGS; secondary beam; kaon beam; separated beam; Wien filter; beam optics AB The optics design and the measured performance are described for LESB3, the 800-MeV/c kaon beamline at the Brookhaven AGS used by E787 to search for rare K+ decays. The beamline provides a flux of similar to 5 x 10(5)K(+)/10(12) protons on target, with a Kin ratio of > 3. (C) 2000 Elsevier Science B.V. All rights reserved. C1 TRIUMF, Vancouver, BC V6T 2A3, Canada. Brookhaven Natl Lab, Upton, NY 11973 USA. CEA Saclay, DSM, DAPNIA, SEA, F-91191 Gif Sur Yvette, France. RP Doornbos, J (reprint author), TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3, Canada. NR 7 TC 17 Z9 17 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 21 PY 2000 VL 444 IS 3 BP 546 EP 556 DI 10.1016/S0168-9002(99)01178-X PG 11 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 307GB UT WOS:000086644100003 ER PT J AU Peng, H Asztalos, S Daw, E Golubev, NA Hagmann, C Kinion, D LaVeigne, J Moltz, DM Nezrick, F Powell, J Rosenberg, LJ Sikivie, P Stoeffl, W Sullivan, NS Tanner, DB Turner, MS van Bibber, K AF Peng, H Asztalos, S Daw, E Golubev, NA Hagmann, C Kinion, D LaVeigne, J Moltz, DM Nezrick, F Powell, J Rosenberg, LJ Sikivie, P Stoeffl, W Sullivan, NS Tanner, DB Turner, MS van Bibber, K TI Cryogenic cavity detector for a large-scale cold dark-matter axion search SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE axions; dark matter; microwave detector ID COSMIC AXIONS; INVISIBLE-AXION; HARMLESS AXION; CP INVARIANCE; AMPLIFIER; COSMOLOGY; PARTICLES AB An axion detector consisting of a tunable high-e cavity, a superconducting magnet, and a superheterodyne receiver with an ultra-low noise pre-amplifier has been built to search for galactic halo axions in the mass range of 1.3-13 mu eV. The detector instrumentation, search process, and data analysis are described. For the first time, this class of detector has reached sufficient sensitivity to detect halo axions with high confidence. (C) 2000 Elsevier Science B.V. All rights reserved. C1 MIT, Dept Phys, Cambridge, MA 02139 USA. MIT, Nucl Sci Lab, Cambridge, MA 02139 USA. Russian Acad Sci, Inst Nucl Res, Moscow 117312, Russia. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Florida, Dept Phys, Gainesville, FL 32611 USA. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Chicago, Enrico Fermi Inst, Dept Astron & Astrophys, FNAL,NASA Astrophys Ctr, Chicago, IL 60637 USA. Univ Chicago, Enrico Fermi Inst, Dept Phys, FNAL,NASA Astrophys Ctr, Chicago, IL 60637 USA. RP Asztalos, S (reprint author), MIT, Dept Phys, 77 Massachusetts Ave, Cambridge, MA 02139 USA. NR 28 TC 29 Z9 29 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 21 PY 2000 VL 444 IS 3 BP 569 EP 583 DI 10.1016/S0168-9002(99)00971-7 PG 15 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 307GB UT WOS:000086644100005 ER PT J AU Toporkov, DK Wojtsekhowski, BB AF Toporkov, DK Wojtsekhowski, BB TI Mechanical filter for alkali atoms SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE laser-driven polarized source; atoms separation; Monte Carlo simulation AB A device for separating gases of different mass is discussed. Such a device could be used in a laser-driven spin exchange source of polarized hydrogen atoms to reduce the contamination of alkali atoms. A Monte Carlo simulation has shown that the suggested apparatus based on a commercial turbo pump could reduce by a factor of 10-15 the concentration of the alkali-metal atoms in the hydrogen flow from a laser driven polarized source. This would greatly enhance the effective polarization in hydrogen targets. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Budker Inst Nucl Phys, Novosibirsk 630090, Russia. Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. RP Toporkov, DK (reprint author), Budker Inst Nucl Phys, Novosibirsk 630090, Russia. NR 2 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 21 PY 2000 VL 444 IS 3 BP 631 EP 634 DI 10.1016/S0168-9002(99)01174-2 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 307GB UT WOS:000086644100012 ER PT J AU Rofer, CK Kaasik, T Waclawek, Z AF Rofer, CK Kaasik, T Waclawek, Z TI Physical hazards of tailings dams SO SCIENCE LA English DT Letter C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. OkoSil Ltd, EE-10134 Tallinn, Estonia. Natl Atom Energy Agcy, PL-00921 Warsaw, Poland. RP Rofer, CK (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 1 TC 2 Z9 2 U1 2 U2 3 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 APR 21 PY 2000 VL 288 IS 5465 BP 439 EP 439 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 306YJ UT WOS:000086626000016 PM 10798977 ER PT J AU Quigg, C AF Quigg, C TI Thinking about physics SO SCIENCE LA English DT Book Review C1 Fermi Natl Accelerator Lab, Dept Theoret Phys, Batavia, IL 60510 USA. RP Quigg, C (reprint author), Fermi Natl Accelerator Lab, Dept Theoret Phys, POB 500, Batavia, IL 60510 USA. NR 1 TC 0 Z9 0 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 APR 21 PY 2000 VL 288 IS 5465 BP 447 EP 447 DI 10.1126/science.288.5465.447 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 306YJ UT WOS:000086626000023 ER PT J AU Orenstein, J Millis, AJ AF Orenstein, J Millis, AJ TI Advances in the physics of high-temperature superconductivity SO SCIENCE LA English DT Review ID 2-DIMENSIONAL HUBBARD-MODEL; A-B PLANE; NORMAL-STATE; CUPRATE SUPERCONDUCTORS; SURFACE IMPEDANCE; FLUX-QUANTIZATION; PENETRATION DEPTH; DOPING DEPENDENCE; PHASE-SEPARATION; GAP ANISOTROPY AB The high-temperature copper oxide superconductors are of fundamental and enduring interest. They not only manifest superconducting transition temperatures inconceivable 15 years ago, but also exhibit many other properties apparently incompatible with conventional metal physics. The materials expand our notions of what is possible, and compel us to develop new experimental techniques and theoretical concepts, This article provides a perspective on recent developments and their implications for our understanding of interacting electrons in metals. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA. RP Orenstein, J (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Orenstein, Joseph/I-3451-2015 NR 96 TC 582 Z9 589 U1 23 U2 181 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 APR 21 PY 2000 VL 288 IS 5465 BP 468 EP 474 DI 10.1126/science.288.5465.468 PG 9 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 306YJ UT WOS:000086626000034 ER PT J AU Fuhrer, MS Nygard, J Shih, L Forero, M Yoon, YG Mazzoni, MSC Choi, HJ Ihm, J Louie, SG Zettl, A McEuen, PL AF Fuhrer, MS Nygard, J Shih, L Forero, M Yoon, YG Mazzoni, MSC Choi, HJ Ihm, J Louie, SG Zettl, A McEuen, PL TI Crossed nanotube junctions SO SCIENCE LA English DT Article ID CARBON NANOTUBES; SINGLE-WALL AB Junctions consisting of two crossed single-walled carbon nanotubes were fabricated with electrical contacts at each end of each nanotube. The individual nanotubes were identified as metallic (M) or semiconducting (S), based on their two-terminal conductances; MM, MS, and SS four-terminal devices were studied. The MM and SS junctions had high conductances, on the order of 0.1 e(2)/h (where e is the electron charge and h is Planck's constant). For an MS junction, the semiconducting nanotube was depleted at the junction by the metallic nanotube, forming a rectifying Schottky barrier. We used two- and three-terminal experiments to fully characterize this junction. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Seoul Natl Univ, Dept Phys, Seoul 151742, South Korea. Seoul Natl Univ, Ctr Theoret Phys, Seoul 151742, South Korea. RP McEuen, PL (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Fuhrer, Michael/E-7634-2010; Yoon, Young-Gui/C-2978-2008; Nygard, Jesper/F-5113-2014; Choi, Hyoung Joon/N-8933-2015; Zettl, Alex/O-4925-2016 OI Fuhrer, Michael/0000-0001-6183-2773; Yoon, Young-Gui/0000-0002-1071-8628; Nygard, Jesper/0000-0002-4639-5314; Choi, Hyoung Joon/0000-0001-8565-8597; Zettl, Alex/0000-0001-6330-136X NR 17 TC 910 Z9 928 U1 14 U2 135 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 APR 21 PY 2000 VL 288 IS 5465 BP 494 EP 497 DI 10.1126/science.288.5465.494 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 306YJ UT WOS:000086626000039 ER PT J AU Nelson, DH Walters, DL MacKerrow, EP Schmitt, MJ Quick, CR Porch, WM Petrin, RR AF Nelson, DH Walters, DL MacKerrow, EP Schmitt, MJ Quick, CR Porch, WM Petrin, RR TI Wave optics simulation of atmospheric turbulence and reflective speckle effects in CO2 lidar SO APPLIED OPTICS LA English DT Article ID DIFFERENTIAL ABSORPTION; NUMERICAL-SIMULATION; PHASE-SCREEN; RANDOM-MEDIA; PROPAGATION; BEAM; SCINTILLATION; STATISTICS; BACKSCATTER; IRRADIANCE AB Laser speckle can influence lidar measurements from a diffuse hard target. Atmospheric optical turbulence will also affect the lidar return signal. We present a numerical simulation that models the propagation of a lidar beam and accounts for both reflective speckle and atmospheric turbulence effects. Our simulation is based on implementing a Huygens-Fresnel approximation to laser propagation. A series of phase screens, with the appropriate atmospheric statistical characteristics, are used to simulate the effect of atmospheric turbulence. A single random phase screen is used to simulate scattering of the entire beam from a rough surface. We compare the output of our numerical model with separate CO2 lidar measurements of atmospheric turbulence and reflective speckle. We also compare the output of our model with separate analytical predictions for atmospheric turbulence and reflective speckle. Good agreement was found between the model and the experimental data. Good agreement was also found with analytical predictions. Finally, we present results of a simulation of the combined effects on a finite-aperture lidar system that are qualitatively consistent with previous experimental observations of increasing rms noise with increasing turbulence level. (C) 2000 Optical Society of America. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. USN, Postgrad Sch, Dept Phys, Monterey, CA 93943 USA. RP Nelson, DH (reprint author), Raytheon Co, Bldg 801,MS E6A,POB 11337, Tucson, AZ 85734 USA. EM dnelson1@notes.west.raytheon.com; rrp@lanl.gov NR 54 TC 15 Z9 17 U1 0 U2 3 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 APR 20 PY 2000 VL 39 IS 12 BP 1857 EP 1871 DI 10.1364/AO.39.001857 PG 15 WC Optics SC Optics GA 306LQ UT WOS:000086598500001 PM 18345082 ER PT J AU Cote, P Marzke, RO West, MJ Minniti, D AF Cote, P Marzke, RO West, MJ Minniti, D TI Evidence for the hierarchical formation of the galactic spheroid SO ASTROPHYSICAL JOURNAL LA English DT Review DE galaxies : halos; galaxies : spiral; Galaxy : evolution; Galaxy : halo; Galaxy : structure; globular clusters : general ID GLOBULAR-CLUSTER SYSTEM; DWARF ELLIPTIC GALAXIES; HALO METALLICITY DISTRIBUTION; LARGE-SCALE STRUCTURE; PROPER-MOTION STARS; COLD DARK MATTER; RR-LYRAE STARS; LOCAL GROUP; LUMINOSITY FUNCTION; MILKY-WAY AB The possibility that the Galactic spheroid was assembled from isolated, chemically distinct proto-Galactic fragments is investigated using a Monte Carlo technique designed to simulate the chemical evolution of the Galaxy in hierarchical formation scenarios which involve no gas dissipation. By comparing the observed and simulated metallicity distributions of Galactic globular clusters and halo field stars, we estimate the level of fragmentation in the collapsing proto-Galaxy. Although the formation process is highly stochastic, the simulations frequently show good agreement with the observed metallicity distributions, provided the luminosity function of proto-Galactic fragments had the form dN proportional to L-alpha dL, where alpha similar to -2. While this steep slope is strongly at odds with the presently observed luminosity function of the Local Group, it is in close agreement with the predictions of semianalytic and numerical models of hierarchical galaxy formation. We discuss a number of possible explanations for this discrepancy. These simulations suggest that the Galactic halo and its globular cluster system were assembled via the accretion and disruption of similar to 10(3) metal-poor, proto-Galactic fragments by the dominant building block: a protobulge whose own metal-rich globular clusters system has been preferentially eroded by dynamical processes. This formation scenario may provide a simple explanation for the different shapes of the Galactic globular cluster and halo star metallicity distributions. Based on the similar properties of globular clusters belonging to spiral and giant elliptical galaxies, we argue that the same process (e.g., hierarchical growth involving little gas dissipation) is responsible for the formation of both giant elliptical galaxies and the bulge-halo components of spiral galaxies. C1 CALTECH, Pasadena, CA 91125 USA. Carnegie Inst Washington Observ, Pasadena, CA 91101 USA. St Marys Univ, Dept Phys & Astron, Halifax, NS B3H 3C3, Canada. Univ Hawaii, Dept Phys & Astron, Hilo, HI 96720 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Pontificia Univ Catolica Chile, Dept Astron & Astrophys, Santiago 22, Chile. RP Cote, P (reprint author), CALTECH, Mail Stop 105-24, Pasadena, CA 91125 USA. NR 133 TC 88 Z9 88 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2000 VL 533 IS 2 BP 869 EP 883 DI 10.1086/308709 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 313GA UT WOS:000086990900022 ER PT J AU Hurley, K Laros, J Brandt, S Fenimore, EE Klebesadel, RW Terrell, J Cline, T Barat, C Boer, M Dezalay, JP Sunyaev, R Terekhov, O Kuznetsov, A Sazonov, S Lund, N Claret, A Paul, J Castro-Tirado, A AF Hurley, K Laros, J Brandt, S Fenimore, EE Klebesadel, RW Terrell, J Cline, T Barat, C Boer, M Dezalay, JP Sunyaev, R Terekhov, O Kuznetsov, A Sazonov, S Lund, N Claret, A Paul, J Castro-Tirado, A TI Gamma-ray burst arrival-time localizations: Simultaneous observations by Ulysses, Pioneer Venus Orbiter, SIGMA, WATCH, and PHEBUS SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts ID CATALOG; SUPPLEMENT; REDSHIFT AB Between the launch of the Ulysses spacecraft in 1990 October and the entry of Pioneer Venus Orbiter (PVO) into the atmosphere of Venus in 1992 October, concurrent coverage by Ulysses, PVO, the WATCH experiments aboard the Granat and Eureca spacecraft, and the SIGMA and PHEBUS experiments aboard the Granat spacecraft was obtained for numerous gamma-ray bursts. Fifteen of them were detected by three or more instruments on spacecraft separated by distances of several AU and could therefore be accurately localized by triangulation. In some cases, independent, accurate locations were obtained by SIGMA and/or WATCH. We present these localizations, which range in area from 0.9 to 530 arcmin(2). C1 Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85715 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Ctr Etud Spatiale Rayonnements, F-31029 Toulouse, France. Moscow Space Res Inst, Moscow 117810, Russia. Danish Space Res Inst, DK-2100 Copenhagen, Denmark. Ctr Etud Saclay, F-91191 Gif Sur Yvette, France. Inst Nacl Invest Agr, LAEFF, E-28080 Madrid, Spain. RP Hurley, K (reprint author), Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. OI Castro-Tirado, A. J./0000-0003-2999-3563; Boer, Michel/0000-0001-9157-4349 NR 21 TC 20 Z9 20 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2000 VL 533 IS 2 BP 884 EP 889 DI 10.1086/308675 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 313GA UT WOS:000086990900023 ER PT J AU Li, H Finn, JM Lovelace, RVE Colgate, SA AF Li, H Finn, JM Lovelace, RVE Colgate, SA TI Rossby wave instability of thin accretion disks. II. Detailed linear theory SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; hydrodynamics; instabilities; waves ID DIFFERENTIALLY ROTATING-DISKS; AXISYMMETRIC UNSTABLE MODES; ANGULAR-MOMENTUM; DYNAMICAL STABILITY; SLENDER TORI; SIMULATIONS; REDISTRIBUTION; TURBULENCE; TRANSPORT; FLOW AB In an earlier work we identified a global, nonaxisymmetric instability associated with the presence of an extreme in the radial profile of the key function L(r) drop (Sigma Omega/k(2))S-2/Gamma in a thin, inviscid, nonmagnetized accretion disk. Here Sigma(r) is the surface mass density of the disk, Omega(r) is the angular rotation rate, S(r) is the specific entropy, Gamma is the adiabatic index, and kappa(r) is the radial epicyclic frequency. The dispersion relation of the instability was shown to be similar to that of Rossby waves in planetary atmospheres. In this paper, we present the detailed linear theory of this Rossby wave instability and show that it exists for a wider range of conditions, specifically, for the case where there is a "jump" over some range of r in Sigma(r) or in the pressure P(r). We elucidate the physical mechanism of this instability and its dependence on various parameters, including the magnitude of the "bump" or "jump," the azimuthal mode number, and the sound speed in the disk. We find a large parameter range where the disk is stable to axisymmetric perturbations but unstable to the nonaxisymmetric Rossby waves. We find that growth rates of the Rossby wave instability can be high, similar to 0.2 Omega(K) for relative small jumps or bumps. We discuss possible conditions which can lead to this instability and the consequences of the instability. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. RP Li, H (reprint author), Univ Calif Los Alamos Natl Lab, T-6,MS B288, Los Alamos, NM 87545 USA. NR 37 TC 144 Z9 146 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 APR 20 PY 2000 VL 533 IS 2 BP 1023 EP 1034 DI 10.1086/308693 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 313GA UT WOS:000086990900037 ER PT J AU Atkins, R Benbow, W Berley, D Chen, ML Coyne, DG Dingus, BL Dorfan, DE Ellsworth, RW Evans, D Falcone, A Fleysher, L Fleysher, R Gisler, G Goodman, JA Haines, TJ Hoffman, CM Hugenberger, S Kelley, LA Leonor, I McConnell, M McCullough, JF McEnery, JE Miller, RS Mincer, AI Morales, MF Nemethy, P Ryan, JM Shen, B Shoup, A Sinnis, C Smith, AJ Sullivan, GW Tumer, T Wang, K Wascko, MO Westerhoff, S Williams, DA Yang, T Yodh, GB AF Atkins, R Benbow, W Berley, D Chen, ML Coyne, DG Dingus, BL Dorfan, DE Ellsworth, RW Evans, D Falcone, A Fleysher, L Fleysher, R Gisler, G Goodman, JA Haines, TJ Hoffman, CM Hugenberger, S Kelley, LA Leonor, I McConnell, M McCullough, JF McEnery, JE Miller, RS Mincer, AI Morales, MF Nemethy, P Ryan, JM Shen, B Shoup, A Sinnis, C Smith, AJ Sullivan, GW Tumer, T Wang, K Wascko, MO Westerhoff, S Williams, DA Yang, T Yodh, GB TI Evidence for TeV emission from GRB 970417a SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts; gamma rays : observations ID GAMMA-RAY BURST; VERY-HIGH-ENERGY; SEARCH; ABSORPTION; ASTRONOMY; ARRAY AB Milagrito, a detector sensitive to very high energy gamma rays, monitored the northern sky from 1997 February through 1998 May. With a large field of view and a high duty cycle, this instrument was well suited to perform a search for TeV gamma-ray bursts (GRBs). We report on a search made for TeV counterparts to GRBs observed by BATSE. BATSE detected 54 GRBs within the field of view of Milagrito during this period. An excess of events coincident in time and space with one of these bursts, GRB 970417a, was observed by Milagrito. The excess has a chance probability of 2.8 x 10(-5) of being a fluctuation of the background. The probability for observing an excess at least this large from any of the 54 bursts is 1.5 x 10(-3). No significant correlations were detected from the other bursts. C1 Univ Utah, Salt Lake City, UT 84112 USA. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. Univ Maryland, College Pk, MD 20742 USA. Natl Sci Fdn, Arlington, VA 22230 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. George Mason Univ, Fairfax, VA 22030 USA. Univ New Hampshire, Durham, NH 03824 USA. NYU, New York, NY 10003 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Calif Irvine, Irvine, CA 92697 USA. Univ Calif Riverside, Riverside, CA 92521 USA. RP Atkins, R (reprint author), Univ Utah, Salt Lake City, UT 84112 USA. NR 24 TC 128 Z9 131 U1 1 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2000 VL 533 IS 2 BP L119 EP L122 DI 10.1086/312629 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 313GC UT WOS:000086991100012 ER PT J AU Blasi, P Epstein, RI Olinto, AV AF Blasi, P Epstein, RI Olinto, AV TI Ultra-high-energy cosmic rays from young neutron star winds SO ASTROPHYSICAL JOURNAL LA English DT Article DE acceleration of particles; magnetic fields; MHD; plasmas ID PULSAR WINDS; MICROWAVE-RADIATION; SUPERNOVA-REMNANTS; CRAB-NEBULA; SPECTRUM; ACCELERATION; INSTABILITY; CUTOFF AB The long-held notion that the highest energy cosmic rays are of distant extragalactic origin is challenged by observations that events above similar to 10(20) eV do not exhibit the expected high-energy cutoff from photopion production off the cosmic microwave background. We suggest that these unexpected ultra-high-energy events are due to iron nuclei accelerated from young strongly magnetized neutron stars through relativistic MHD winds. We find that neutron stars whose initial spin periods are shorter than similar to 10 ms and whose surface magnetic fields are in the 10(12)-10(14) G range can accelerate iron cosmic rays to greater than similar to 10(20) eV. These ions can pass through the remnant of the supernova explosion that produced the neutron star without suffering significant spallation reactions or energy loss. For plausible models of the Galactic magnetic field, the trajectories of the iron ions curve sufficiently to be consistent with the observed, largely isotropic arrival directions of the highest energy events. C1 NASA, Fermilab Astrophys Grp, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. RP Blasi, P (reprint author), NASA, Fermilab Astrophys Grp, Fermi Natl Accelerator Lab, Box 500, Batavia, IL 60510 USA. RI Blasi, Pasquale/O-9345-2015 OI Blasi, Pasquale/0000-0003-2480-599X NR 47 TC 92 Z9 93 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2000 VL 533 IS 2 BP L123 EP L126 DI 10.1086/312626 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 313GC UT WOS:000086991100013 ER PT J AU Borozdin, KN Trudolyubov, SP AF Borozdin, KN Trudolyubov, SP TI Detection of a 5 Hz quasi-periodic oscillation from X-ray nova GRS 1739-278 SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : close; black hole physics; stars : individual (GRS 1739-278); X-rays : stars ID RXTE OBSERVATIONS; HIGH STATE; GRS-1739-278; TRANSIENT; VARIABILITY; SCORPIUS; GX-339-4 AB The X-ray nova GRS 1739-278 flared up near the Galactic center in the spring of 1996. Here we report on the discovery of an similar to 5 Hz quasi-periodic oscillation (QPO) in Rossi X-Ray Timing Explorer/PCA observations of GRS 1739-278. The QPO was only present when the source was in its very high state and disappeared later, when it made a transition down into the high state. We present the energy spectra of this black hole candidate measured in both high and very high states and discuss the similarities between this system and other X-ray transients. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Russian Acad Sci, Inst Space Res, Moscow V71, Russia. RP Borozdin, KN (reprint author), Univ Calif Los Alamos Natl Lab, NIS-2, Los Alamos, NM 87545 USA. NR 35 TC 7 Z9 7 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2000 VL 533 IS 2 BP L131 EP L134 DI 10.1086/312625 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 313GC UT WOS:000086991100015 ER PT J AU Mathur, S Green, PJ Arav, N Brotherton, M Crenshaw, M DeKool, M Elvis, M Goodrich, RW Hamann, F Hines, DC Kashyap, V Korista, K Peterson, BM Shields, JC Shlosman, I van Breugel, W Voit, M AF Mathur, S Green, PJ Arav, N Brotherton, M Crenshaw, M DeKool, M Elvis, M Goodrich, RW Hamann, F Hines, DC Kashyap, V Korista, K Peterson, BM Shields, JC Shlosman, I van Breugel, W Voit, M TI Thomson thick X-ray absorption in a broad absorption line quasar, PG 0946+301 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; quasars : absorption lines; quasars : individual (PG 0946+301); X-rays : galaxies ID ABUNDANCES; PHL-5200 AB We present a deep ASCA observation of a broad absorption line quasar (BALQSQ) PG 0946+301. The source was clearly detected in one of the gas imaging spectrometers, but not in any other detector. If BALQSOs have intrinsic X-ray spectra similar to normal radio-quiet quasars, our observations imply that there is Thomson thick X-ray absorption (N-H greater than or similar to 10(24) cm(-2)) toward PG 0946+301. This is the largest column density estimated so far toward a BALQSO. The absorber must be at least partially ionized and may be responsible for attenuation in the optical and UV. If the Thomson optical depth toward BALQSOs is close to 1, as inferred here, then spectroscopy in hard X-rays with large telescopes like XMM would be feasible. C1 Ohio State Univ, Columbus, OH 43220 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Calif Berkeley, Berkeley, CA 94720 USA. Natl Opt Astron Observ, Tucson, AZ 85726 USA. Catholic Univ, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Australian Natl Univ, Res Sch Astron & Astrophys, Weston Creek, ACT 2611, Australia. WM Keck Observ, Kamuela, HI 96743 USA. Univ Florida, Gainesville, FL 32611 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Western Michigan Univ, Kalamazoo, MI 49008 USA. Ohio Univ, Athens, OH 45701 USA. Univ Kentucky, Lexington, KY 40506 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. RP Mathur, S (reprint author), Ohio State Univ, Columbus, OH 43220 USA. NR 22 TC 30 Z9 30 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2000 VL 533 IS 2 BP L79 EP L82 DI 10.1086/312617 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 313GC UT WOS:000086991100003 ER PT J AU Paerels, F Cottam, J Sako, M Liedahl, DA Brinkman, AC van der Meer, RLJ Kaastra, JS Predehl, P AF Paerels, F Cottam, J Sako, M Liedahl, DA Brinkman, AC van der Meer, RLJ Kaastra, JS Predehl, P TI High-resolution spectroscopy of the X-ray-photoionized wind in Cygnus X-3 with the Chandra high-energy transmission grating spectrometer SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic processes; stars : individual (Cygnus X-3); techniques : spectroscopic; X-rays : stars ID LINE; EMISSION; IRON AB We present a preliminary analysis of the 1-10 keV spectrum of the massive X-ray binary Cygnus X-3, obtained with the high-energy transmission grating spectrometer on the Chandra X-Ray Observatory. The source reveals a richly detailed discrete emission spectrum, with clear signatures of photoionization-driven excitation. Among the spectroscopic novelties in the data are the first astrophysical detections of a number of He like "triplets" (Si, S, Ar) with emission-line ratios characteristic of photoionization equilibrium, fully resolved narrow radiative recombination continua of Mg, Si, and S, the presence of the H-like Fe Balmer series, and a clear detection of an similar to 800 km s(-1) large-scale velocity field as well as an similar to 1500 km s(-1) FWHM Doppler broadening in the source. We briefly touch on the implications of these findings for the structure of the Wolf-Rayet wind. C1 Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. SRON, Space Res Lab, NL-3584 CA Utrecht, Netherlands. Univ Calif Lawrence Livermore Natl Lab, Dept Phys, Livermore, CA 94550 USA. Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. RP Paerels, F (reprint author), Columbia Univ, Columbia Astrophys Lab, 538 W 120th St, New York, NY 10027 USA. NR 13 TC 55 Z9 55 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2000 VL 533 IS 2 BP L135 EP L138 DI 10.1086/312608 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 313GC UT WOS:000086991100016 ER PT J AU Shigemori, K Ditmire, T Remington, BA Yanovsky, V Ryutov, D Estabrook, KG Edwards, MJ MacKinnon, AJ Rubenchik, AM Keilty, KA Liang, E AF Shigemori, K Ditmire, T Remington, BA Yanovsky, V Ryutov, D Estabrook, KG Edwards, MJ MacKinnon, AJ Rubenchik, AM Keilty, KA Liang, E TI Developing a radiative shock experiment relevant to astrophysics SO ASTROPHYSICAL JOURNAL LA English DT Article DE conduction; hydrodynamics; ISM : kinematics and dynamics; radiative transfer; shock waves; supernova remnants ID SUPERNOVA-REMNANTS; INTERSTELLAR CLOUD; ATOMIC CLUSTERS; PLASMA; HYDRODYNAMICS; WAVES AB We report on the initial results of experiments being developed on the Falcon laser to simulate radiative astrophysical shocks. Cylindrically diverging blast waves were produced in low-density (similar to 10(18) cm(-3)), high-Z gas by laser-irradiating Xe gas jets containing atomic clusters. The blast-wave trajectory was measured by Michelson interferometry. The velocity for the blast wave is slightly less than the adiabatic Sedov-Taylor prediction, and an ionization precursor is observed ahead of the shock front. This suggests energy loss through radiative cooling and reduced compression due to preheat deposited ahead of the shock, both consistent with one-dimensional radiation hydrodynamics simulations. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Osaka Univ, Inst Laser Engn, Suita, Osaka 5650871, Japan. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Rice Univ, Dept Space Phys & Astron, Houston, TX 77005 USA. RP Shigemori, K (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94551 USA. RI Yanovsky, Victor/B-5899-2008; MacKinnon, Andrew/P-7239-2014 OI MacKinnon, Andrew/0000-0002-4380-2906 NR 25 TC 35 Z9 36 U1 0 U2 4 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 APR 20 PY 2000 VL 533 IS 2 BP L159 EP L162 DI 10.1086/312621 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 313GC UT WOS:000086991100022 ER PT J AU Stern, D Spinrad, H Eisenhardt, P Bunker, AJ Dawson, S Stanford, SA Elston, R AF Stern, D Spinrad, H Eisenhardt, P Bunker, AJ Dawson, S Stanford, SA Elston, R TI Discovery of a color-selected quasar at z=5.50 SO ASTROPHYSICAL JOURNAL LA English DT Article DE early universe; quasars : general; quasars : individual (RD J030117+002025) ID SPECTROSCOPIC CCD-SURVEYS; HIGH-REDSHIFT QUASARS; HUBBLE DEEP FIELD; LUMINOSITY FUNCTION; SKY SURVEY; GALAXIES; EVOLUTION; EMISSION AB We present observations of RD J030117+002025, a quasar at z = 5.50 discovered from deep, multicolor, ground-based observations covering 74 arcmin(2). This is the most distant quasar or active galaxy currently known. The object was targeted as an R-band dropout, with R-AB > 26.3 (3 sigma limit in a 3 " diameter region), I-AB = 23.8, and z(AB) = 23.4. The Kecknow-Resolution Imaging Spectrometer spectrum shows broad Ly alpha/N v lambda 1240 emission and sharp absorption decrements from the highly redshifted hydrogen forests. The fractional continuum depression due to the Ly alpha forest is D-A = 0.90. RD J030117+002025 is the least luminous high-redshift quasar known (M-B approximate to -22.7). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Inst Astron, Cambridge CB3 0HA, England. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Univ Calif Lawrence Livermore Natl Lab, Davis, CA 95616 USA. Univ Florida, Dept Astron, Gainesville, FL 32611 USA. RP Stern, D (reprint author), CALTECH, Jet Prop Lab, Mail Stop 169-327, Pasadena, CA 91109 USA. NR 32 TC 46 Z9 46 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2000 VL 533 IS 2 BP L75 EP L78 DI 10.1086/312614 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 313GC UT WOS:000086991100002 ER PT J AU McAdams, HH Arkin, A AF McAdams, HH Arkin, A TI Gene regulation: Towards a circuit engineering discipline SO CURRENT BIOLOGY LA English DT Article AB Genetic circuits can now be engineered that perform moderately complicated switching functions or exhibit predictable dynamical behavior. These 'forward engineering' techniques may have to be combined with directed evolution techniques to produce robustness comparable with naturally occurring circuits. C1 Stanford Univ, Med Ctr, Sch Med, Dept Dev Biol, Stanford, CA 94305 USA. Univ Calif Berkeley, Dept Bioengn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, EO Lawrence Berkeley Natl Lab, Phys Biosci Div, Berkeley, CA 94720 USA. RP McAdams, HH (reprint author), Stanford Univ, Med Ctr, Sch Med, Dept Dev Biol, Stanford, CA 94305 USA. RI Arkin, Adam/A-6751-2008 OI Arkin, Adam/0000-0002-4999-2931 NR 13 TC 63 Z9 64 U1 0 U2 3 PU CURRENT BIOLOGY LTD PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 0960-9822 J9 CURR BIOL JI Curr. Biol. PD APR 20 PY 2000 VL 10 IS 8 BP R318 EP R320 DI 10.1016/S0960-9822(00)00440-1 PG 3 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 348GX UT WOS:000088978100012 PM 10801411 ER PT J AU Golde, WT Wood, J Dunn, JJ Dattwyler, RJ Luft, BJ Coyle, P Kalish, R AF Golde, WT Wood, J Dunn, JJ Dattwyler, RJ Luft, BJ Coyle, P Kalish, R TI T cell antigen reactivity to recombinant OspA and the homologous self peptide of LFA-I in patients with Lyme disease. SO FASEB JOURNAL LA English DT Meeting Abstract C1 USDA ARS, Plum Isl Anim Dis Ctr, Greenport, NY 11944 USA. SUNY Stony Brook, Dept Dermatol, Stony Brook, NY 11794 USA. SUNY Stony Brook, Dept Med, Stony Brook, NY 11794 USA. SUNY Stony Brook, Dept Neurol, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD APR 20 PY 2000 VL 14 IS 6 SU S BP A950 EP A950 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 307FQ UT WOS:000086643100226 ER PT J AU Bartels, DM Crowell, RA AF Bartels, DM Crowell, RA TI Photoionization yield vs energy in H2O and D2O SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID GEMINATE PAIR RECOMBINATION; PURE LIQUID WATER; ELECTRONIC-STRUCTURE; RELAXATION DYNAMICS; MOLECULAR-DYNAMICS; AQUEOUS HALIDE; IONIZATION; DISSOCIATION; PHOTODETACHMENT; RADIOLYSIS AB A simple conductivity jump method was used to measure the escaped solvated electron yield following two-photon excitation of water with Raman-shifted light from an amplified mode-locked Nd:YAG laser. Between 7.8 and 9.3 eV, the quantum efficiency for the escape yields changes from 1.9% to 22%, with an almost exponential dependence on the excitation energy. Quantum efficiency in D2O is smaller and resembles the H2O behavior at 0.35 eV lower energy. The quantum yield measured for one-photon excitation near the water absorption edge at 6.4 eV is a surprisingly large 1.3%. We propose that the mechanism for low energy photoionizaton of water is best described as a dissociative proton-coupled electron transfer to a preexisting trap. C1 Argonne Natl Lab, Argonne, IL 60517 USA. RP Bartels, DM (reprint author), Argonne Natl Lab, Chem Div Bldg 200, Argonne, IL 60517 USA. NR 39 TC 64 Z9 65 U1 1 U2 20 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 APR 20 PY 2000 VL 104 IS 15 BP 3349 EP 3355 DI 10.1021/jp9941460 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 307LZ UT WOS:000086655900011 ER PT J AU Franceschetti, A Williamson, A Zunger, A AF Franceschetti, A Williamson, A Zunger, A TI Addition spectra of quantum dots: the role of dielectric mismatch SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Letter ID SEMICONDUCTOR NANOCRYSTALLITES; ELECTRON; COULOMB; ENERGIES; SILICON; MATRIX AB Using atomistic pseudopotential wave functions, we calculate the electron and hole addition energies and the quasi-particle gap of InAs quantum dots. We find that the addition energies and the quasi-particle gap depend strongly on the dielectric constant epsilon(out) of the surrounding material, and that when epsilon(out) is much smaller than the dielectric constant of the dot the electron-electron and hole-hole interactions are dominated by surface polarization effects. We predict the addition energies and the quasi-particle gap as a function of size and epsilon(out), and compare our results with recent single-dot tunneling spectroscopy experiments. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Franceschetti, A (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. NR 18 TC 70 Z9 70 U1 0 U2 10 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 APR 20 PY 2000 VL 104 IS 15 BP 3398 EP 3401 DI 10.1021/jp0000026 PG 4 WC Chemistry, Physical SC Chemistry GA 307LW UT WOS:000086655600004 ER PT J AU Edman, L Doeff, MM Ferry, A Kerr, J De Jonghe, LC AF Edman, L Doeff, MM Ferry, A Kerr, J De Jonghe, LC TI Transport properties of the solid polymer electrolyte system P(EO)(n)LiTFSI SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID TRANSFERENCE NUMBER MEASUREMENTS; POLY(ETHYLENE OXIDE); OXIDE)-LICF3SO3 SYSTEM; CONDUCTIVITY BEHAVIOR; RUBBERY ELECTROLYTES; SALT COMPLEXES; PHASE-DIAGRAMS; PEO; LICF3SO3; DIFFUSION AB Values for the lithium ion transference number (t(+)(0)) are reported for the solid polymer electrolyte system poly(ethylene oxide) (PEO) complexed with Li(CF3SO2)(2)N (LiTFSI). t(+)(0),ranges from 0.17 +/- 0.17 to 0.60 +/- 0.03 in the salt concentration (c) region of 742 to 2982 mol/m(3) at 85 degrees C. The concentration dependence of t(+)(0) and the molar ionic conductivity (Lambda) are shown to be in good agreement with a free volume approach over the salt-rich composition range investigated. The present t(+)(0) results were obtained using an electrochemical technique based on concentrated solution theory. This experimentally straightforward method is herein demonstrated to give accurate results for a highly concentrated SPE system, without relying on any dubious simplifications regarding the state of the electrolyte. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. Monash Univ, Dept Mat Engn, Clayton, Vic 3168, Australia. RP Edman, L (reprint author), Umea Univ, Dept Expt Phys, S-90187 Umea, Sweden. RI Doeff, Marca/G-6722-2013 OI Doeff, Marca/0000-0002-2148-8047 NR 47 TC 76 Z9 76 U1 5 U2 44 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 APR 20 PY 2000 VL 104 IS 15 BP 3476 EP 3480 DI 10.1021/jp993897z PG 5 WC Chemistry, Physical SC Chemistry GA 307LW UT WOS:000086655600017 ER PT J AU Grigsby, JJ Blanch, HW Prausnitz, JM AF Grigsby, JJ Blanch, HW Prausnitz, JM TI Diffusivities of lysozyme in aqueous MgCl2 solutions from dynamic light-scattering data: Effect of protein and salt concentrations SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID PREFERENTIAL INTERACTIONS; CORRELATION SPECTROSCOPY; INTEGRAL-EQUATIONS; SELF-ASSOCIATION; CRYSTAL-GROWTH; PHASE-BEHAVIOR; CRYSTALLIZATION; DIFFUSION; HYDRATION; PARTICLES AB Dynamic light-scattering (DLS) studies are reported for lysozyme in aqueous magnesium chloride solutions at ionic strengths 0.6, 0.8, and 1.0 M for a temperature range 10-30 degrees C at pH 4.0. The diffusion coefficient of lysozyme was calculated as a function of protein concentration, salt concentration, temperature, and scattering angle. A Zimm-plot analysis provided the infinitely-dilute diffusion coefficient and the protein-concentration dependence of the diffusion coefficient. The hydrodynamic radius of a lysozyme monomer was obtained from the Stokes-Einstein equation; it is 18.6 +/- 1.0 Angstrom. The difference (1.4 Angstrom) between the hydrodynamic and the crystal-structure radius is attributed to binding of Mg2+ ions to the protein surface and subsequent water structuring. The effect of protein concentration on the diffusion coefficient indicates that attractive interactions increase as the temperature falls at fixed salt concentration. However, when plotted against ionic strength, attractive interactions exhibit a maximum at ionic strength 0.84 M, probably because Mg2+-protein binding and water structuring become increasingly important as the concentration of magnesium ion rises. The present work suggests that inclusion of ion binding and water structuring at the protein surface in a pair-potential model is needed to achieve accurate predictions of protein-solution phase behavior. C1 Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Prausnitz, JM (reprint author), Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. NR 43 TC 39 Z9 39 U1 1 U2 10 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 APR 20 PY 2000 VL 104 IS 15 BP 3645 EP 3650 DI 10.1021/jp993177s PG 6 WC Chemistry, Physical SC Chemistry GA 307LW UT WOS:000086655600039 ER PT J AU Shkrob, IA Sauer, MC Trifunac, AD AF Shkrob, IA Sauer, MC Trifunac, AD TI Reversible reactions of cycloalkane solvent holes. 1. Complexation of cis- and trans-decalin(center dot+) with alcohols SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID HIGH-MOBILITY IONS; TRANS-DECALIN; RADICAL CATIONS; IRRADIATED CYCLOHEXANE; LIQUID ALKANES; HYDROCARBONS; SPECTROSCOPY; VISCOSITY; MOLECULES; INJECTION AB It is shown that solvent holes in cis- and trans-decalin form complexes with aliphatic alcohols that live 1-100 ns, depending on the solute and the solvent temperature. This complexation has near-zero activation energy and occurs with rate constants of (1-1.2) x 10(11) M-1 s(-1) in trans-decalin and 3 x 10(10) M-1 s(-1) in cis-decalin. The metastable complex decays by proton transfer (for alcohols higher than ethanol); in concentrated solutions a diffusion-controlled reaction of the complex with a second alcohol molecule occurs. While the stability of the complex increases with the carbon number of the alcohol, the standard heat of the complexation decreases in the opposite direction (Delta H degrees changes from -39 kJ/mol for ethanol to -25 kJ/mol for tert-butanol). The decrease in the standard entropy is small (Delta S degrees(298) > -80 J mol(-1) K-1), approaching zero for higher alcohols. We argue that this thermochemistry is due to the polaronic nature of the solvent holes. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Shkrob, IA (reprint author), Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. NR 49 TC 5 Z9 5 U1 1 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 APR 20 PY 2000 VL 104 IS 15 BP 3752 EP 3759 DI 10.1021/jp993988w PG 8 WC Chemistry, Physical SC Chemistry GA 307LW UT WOS:000086655600051 ER PT J AU Shkrob, IA Sauer, MC Trifunac, AD AF Shkrob, IA Sauer, MC Trifunac, AD TI Reversible reactions of cycloalkane solvent holes. 2. Scavenging of cis- and trans-decalin(center dot+) by benzene SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID ELECTRONIC-ENERGY TRANSFER; DIMER CATION (C6H6)2+; HIGH-MOBILITY IONS; AROMATIC-HYDROCARBONS; PULSE-RADIOLYSIS; RADICAL CATIONS; DECALIN; CYCLOHEXANE; KINETICS; LIQUIDS AB Solvent holes in liquid cis- and trans-decalin form metastable complexes with benzene, which are probably solvation complexes of monomer radical cations of benzene. At 25 degrees C, the rate constants of formation of the complexes are, for trans- and cis-decalin respectively 1.1 x 10(11) and 3.6 x 10(10) M-1 s(-1), and the natural lifetime of the complex is 7 ns for trans- and 50 ns for cis-decalin. Thermodynamic potentials for the complexation are determined. The heat of the complex formation is approximate to-26 kJ/mol for trans- and approximate to-18 kJ/mol for cis-decalin. In cis-decalin, the complexes are more stable because of near-zero entropy of the complex formation. The complex decays by proton or H atom transfer with activation energy approximate to 10 kJ/mol (which yields a benzonium cation) or in a reactive encounter with a second benzene molecule (which yields a benzene dimer cation). Laser excitation of the dimer cation with a 1.165- or 2.33 eV photon causes valence band electron transfer and injection of a free solvent hole. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Shkrob, IA (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 40 TC 3 Z9 3 U1 0 U2 0 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 APR 20 PY 2000 VL 104 IS 15 BP 3760 EP 3765 DI 10.1021/jp993989o PG 6 WC Chemistry, Physical SC Chemistry GA 307LW UT WOS:000086655600052 ER PT J AU Breitweg, J Chekanov, S Derrick, M 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 Hartmann, H Heinloth, K Hilger, E Irrgang, P Jakob, HP Kappes, A Katz, UF Kerger, R Paul, E Schnurbusch, H Stifutkin, A Tandler, J Voss, KC Weber, A Wieber, H Bailey, DS Barret, O Brook, NH Foster, B Heath, GP Heath, HF McFall, JD Piccioni, D Rodrigues, E 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 Liu, W Liu, X Mellado, B Paganis, S Sacchi, R Sampson, S Sciulli, F Chwastowski, J Eskreys, A Figiel, J Klimek, K Olkiewicz, K Piotrzkowski, K Przybycien, MB Stopa, P Zawiejski, L Adamczyk, L Bednarek, B Jelen, K Kisielewska, D Kowal, AM Kowalski, T Przybycien, M Rulikowska-Zarebska, E Suszycki, L Szuba, D 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 Milite, M Monteiro, T Moritz, M Notz, D Pelucchi, F Petrucci, MC Rohde, M Saull, PRB Savin, AA Schneekloth, U Selonke, F Sievers, M Stonjek, S Tassi, E Wolf, G Wollmer, U Youngman, C Zeuner, W Coldewey, C Grabosch, HJ Viani, ALD Meyer, A Schlenstedt, S Straub, PB Barbagli, G Gallo, E Pelfer, P Maccarrone, G Votano, L Bamberger, A Benen, A Eisenhardt, S Markun, P Raach, P Wolfle, S Bussey, PJ Doyle, AT Lee, SW Macdonald, N McCance, GJ Saxon, DH Sinclair, LE Skillicorn, IO Waugh, R Bohnet, I Gendner, N Holm, U Meyer-Larsen, A Salehi, H Wick, K Dannheim, D Garfagnini, A Gialas, I Gladilin, LK Kcira, D Klanner, R Lohrmann, E Poelz, G Zetsche, F Goncalo, R Long, KR Miller, DB Tapper, AD Walker, R Mallik, U Cloth, P Filges, D Ishii, T Kuze, M Nagano, K Tokushuku, K Yamada, S Yamazaki, Y Ahn, SH An, SH Hong, SJ Lee, SB Nam, SW Park, SK Lim, H Park, IH Son, D Barreiro, F Garcia, G Glasman, C Gonzalez, O Labarga, L del Peso, J Redondo, I Terron, J Barbi, M Corriveau, F Hanna, DS Ochs, A Padhi, S Riveline, M Stairs, DG Wing, M Tsurugai, T Bashkirov, V Dolgoshein, BA Dementiev, RK Ermolov, PF Golubkov, YA Katkov, II Khein, LA Korotkova, NA Korzhavina, IA Kuzmin, VA Lukina, OY Proskuryakov, AS Shcheglova, LM Solomin, AN Vlasov, NN Zotkin, SA Bokel, C Botje, M Brummer, N Engelen, J Grijpink, S Koffeman, E Kooijman, P Schagen, S van Sighem, A Tiecke, H Tuning, N Velthuis, JJ Vossebeld, J Wiggers, L de Wolf, E Bylsma, B Durkin, LS Gilmore, J Ginsburg, CM Kim, CL Ling, TY Nylander, P Boogert, S Cooper-Sarkar, AM Devenish, RCE Grosse-Knetter, J Matsushita, T Ruske, O Sutton, MR Walczak, R Bertolin, A Brugnera, R Carlin, R Dal Corso, F Dosselli, U Dusini, S Limentani, S Morandin, M Posocco, M Stanco, L Stroili, R Voci, C Iannotti, L Oh, BY Okrasinski, JR Toothacker, WS Whitmore, JJ Iga, Y D'Agostini, G Marini, G Nigro, A 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 Abe, T Fusayasu, T Umemori, K Yamashita, T Hamatsu, R Hirose, T Inuzuka, M Kitamura, S Nishimura, T Arneodo, M Cartiglia, N Cirio, R Costa, M Ferrero, MI Maselli, S Monaco, V Peroni, C 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 West, BJ Ciborowski, J Ciesielski, R 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 Cole, JE Frisken, WR Hall-Wilton, R Khakzad, M Menary, S Schmidke, WB AF Breitweg, J Chekanov, S Derrick, M 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 Hartmann, H Heinloth, K Hilger, E Irrgang, P Jakob, HP Kappes, A Katz, UF Kerger, R Paul, E Schnurbusch, H Stifutkin, A Tandler, J Voss, KC Weber, A Wieber, H Bailey, DS Barret, O Brook, NH Foster, B Heath, GP Heath, HF McFall, JD Piccioni, D Rodrigues, E 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 Liu, W Liu, X Mellado, B Paganis, S Sacchi, R Sampson, S Sciulli, F Chwastowski, J Eskreys, A Figiel, J Klimek, K Olkiewicz, K Piotrzkowski, K Przybycien, MB Stopa, P Zawiejski, L Adamczyk, L Bednarek, B Jelen, K Kisielewska, D Kowal, AM Kowalski, T Przybycien, M Rulikowska-Zarebska, E Suszycki, L Szuba, D 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 Milite, M Monteiro, T Moritz, M Notz, D Pelucchi, F Petrucci, MC Rohde, M Saull, PRB Savin, AA Schneekloth, U Selonke, F Sievers, M Stonjek, S Tassi, E Wolf, G Wollmer, U Youngman, C Zeuner, W Coldewey, C Grabosch, HJ Viani, ALD Meyer, A Schlenstedt, S Straub, PB Barbagli, G Gallo, E Pelfer, P Maccarrone, G Votano, L Bamberger, A Benen, A Eisenhardt, S Markun, P Raach, P Wolfle, S Bussey, PJ Doyle, AT Lee, SW Macdonald, N McCance, GJ Saxon, DH Sinclair, LE Skillicorn, IO Waugh, R Bohnet, I Gendner, N Holm, U Meyer-Larsen, A Salehi, H Wick, K Dannheim, D Garfagnini, A Gialas, I Gladilin, LK Kcira, D Klanner, R Lohrmann, E Poelz, G Zetsche, F Goncalo, R Long, KR Miller, DB Tapper, AD Walker, R Mallik, U Cloth, P Filges, D Ishii, T Kuze, M Nagano, K Tokushuku, K Yamada, S Yamazaki, Y Ahn, SH An, SH Hong, SJ Lee, SB Nam, SW Park, SK Lim, H Park, IH Son, D Barreiro, F Garcia, G Glasman, C Gonzalez, O Labarga, L del Peso, J Redondo, I Terron, J Barbi, M Corriveau, F Hanna, DS Ochs, A Padhi, S Riveline, M Stairs, DG Wing, M Tsurugai, T Bashkirov, V Dolgoshein, BA Dementiev, RK Ermolov, PF Golubkov, YA Katkov, II Khein, LA Korotkova, NA Korzhavina, IA Kuzmin, VA Lukina, OY Proskuryakov, AS Shcheglova, LM Solomin, AN Vlasov, NN Zotkin, SA Bokel, C Botje, M Brummer, N Engelen, J Grijpink, S Koffeman, E Kooijman, P Schagen, S van Sighem, A Tiecke, H Tuning, N Velthuis, JJ Vossebeld, J Wiggers, L de Wolf, E Bylsma, B Durkin, LS Gilmore, J Ginsburg, CM Kim, CL Ling, TY Nylander, P Boogert, S Cooper-Sarkar, AM Devenish, RCE Grosse-Knetter, J Matsushita, T Ruske, O Sutton, MR Walczak, R Bertolin, A Brugnera, R Carlin, R Dal Corso, F Dosselli, U Dusini, S Limentani, S Morandin, M Posocco, M Stanco, L Stroili, R Voci, C Iannotti, L Oh, BY Okrasinski, JR Toothacker, WS Whitmore, JJ Iga, Y D'Agostini, G Marini, G Nigro, A 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 Abe, T Fusayasu, T Umemori, K Yamashita, T Hamatsu, R Hirose, T Inuzuka, M Kitamura, S Nishimura, T Arneodo, M Cartiglia, N Cirio, R Costa, M Ferrero, MI Maselli, S Monaco, V Peroni, C 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 West, BJ Ciborowski, J Ciesielski, R 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 Cole, JE Frisken, WR Hall-Wilton, R Khakzad, M Menary, S Schmidke, WB CA ZEUS Collaborat TI The Q(2) dependence of dijet cross sections in gamma p interactions at HERA SO PHYSICS LETTERS B LA English DT Article ID PHOTON STRUCTURE-FUNCTION; STRUCTURE-FUNCTION F-2(GAMMA); LEADING ORDER QCD; VIRTUAL PHOTON; JET PRODUCTION; PARTON DISTRIBUTIONS; HADRON-COLLISIONS; HARD SCATTERING; PHOTOPRODUCTION; GEV2 AB The dependence of the photon structure on the photon virtuality, Q(2), is studied by measuring the reaction e(+) p --> e(+) + jet + jet + X at photon-proton centre-of-mass energies 134 < W < 223 GeV. Events have been selected in the Q(2) ranges approximate to 0 GeV(2), 0.1-0.55 GeV(2), and 1.5-4.5 GeV(2), having two jets with transverse energy E(f)(jet) > 5.5 GeV in Ihe Final state. The dijet cross section has been measured as a Function of the fractional momentum of the photon participating in the hard process, x(gamma)(OBS). The ratio of the dijet cross section with x(gamma)(OBS) < 0.75 to that with x(gamma)(OBS) > 0.75 decreases as Q(2) increases. The data are compared with the predictions of NLO pQCD and leading-order Monte Carlo programs using various parton distribution functions of the photon. The measurements can be interpreted in terms of a resolved photon component that falls with Q(2) but remains present at values of Q(2) up to 4.5 GeV(2). However, none of the models considered gives a good description of the data. (C) 2000 Elsevier Science B.V. All rights reserved. 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, Cosenza, Italy. Chonnam Natl Univ, Kwangju 500757, South Korea. Columbia Univ, Nevis Labs, Irvington, NY USA. Inst Nucl Phys, Krakow, Poland. Acad Min & Met, Fac Phys & Nucl Techniques, Krakow, Poland. Jagiellonian Univ, Dept Phys, Krakow, Poland. Deutsch Elekt Synchrotron DESY, Hamburg, Germany. DESY Zeuthen, Zeuthen, Germany. Univ Florence, Florence, Italy. Ist Nazl Fis Nucl, I-50125 Florence, Italy. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Univ Freiburg, Fak Phys, D-7800 Freiburg, Germany. Univ Glasgow, Dept Phys & Astron, Glasgow, Lanark, Scotland. Univ Hamburg, Inst Expt Phys 1, Hamburg, Germany. Univ Hamburg, Inst Expt Phys 2, D-2000 Hamburg, Germany. Univ London Imperial Coll Sci Technol & Med, High Energy Nucl Phys Grp, London, England. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. Forschungszentrum Julich, Inst Kernphys, 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 Engn Phys Inst, Moscow 115409, 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, 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, Alessandria, Italy. Ist Nazl Fis Nucl, Alessandria, Italy. Univ Toronto, Dept Phys, Toronto, ON, Canada. UCL, Dept Phys & Astron, London, England. Warsaw Univ, Inst Expt Phys, Warsaw, Poland. Inst Nucl Studies, 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. CNR, IROE, I-50127 Florence, Italy. RP Breitweg, J (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Solomin, Anatoly/C-3072-2016; dusini, stefano/J-3686-2012; Goncalo, Ricardo/M-3153-2016; 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; Dementiev, Roman/K-7201-2012; Katz, Uli/E-1925-2013; Wiggers, Leo/B-5218-2015; Tassi, Enrico/K-3958-2015; Gladilin, Leonid/B-5226-2011; Morandin, Mauro/A-3308-2016 OI dusini, stefano/0000-0002-1128-0664; Goncalo, Ricardo/0000-0002-3826-3442; Castellini, Guido/0000-0002-0177-0643; Capua, Marcella/0000-0002-2443-6525; Abbiendi, Giovanni/0000-0003-4499-7562; 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; Gladilin, Leonid/0000-0001-9422-8636; Morandin, Mauro/0000-0003-4708-4240 NR 60 TC 20 Z9 20 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 APR 20 PY 2000 VL 479 IS 1-3 BP 37 EP 52 DI 10.1016/S0370-2693(00)00311-7 PG 16 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 310BP UT WOS:000086806900007 ER PT J AU Grojean, C AF Grojean, C TI T self-dual transverse space and gravity trapping SO PHYSICS LETTERS B LA English DT Article ID EXTRA DIMENSION; BULK FIELDS; COMPACTIFICATION; STABILIZATION AB We advocate that the orbifold Z(2) symmetry of the gravity trapping model proposed by Randall and Sundrum can be seen, in appropriate coordinates, as a symmetry that exchanges the short distances with the large ones. Using diffeomorphism invariance, we construct extensions defined by patch glued together. A singularity occurs at the junction and it is interpreted as a brane, the jump brane, of codimension one. We give explicit realization in ten and eleven dimensional supergravity and show that the lower dimensional Planck scale on the brane is finite. The standard model would be trapped on a supersymmetric brane located at the origin whereas the jump brane would surround it at a finite distance. The bulk interactions could transmit the supersymmetry breaking from the jump brane to the SM brane. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RP Grojean, C (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. OI grojean, christophe/0000-0002-7196-7361 NR 95 TC 20 Z9 20 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 APR 20 PY 2000 VL 479 IS 1-3 BP 273 EP 283 DI 10.1016/S0370-2693(00)00304-X PG 11 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 310BP UT WOS:000086806900034 ER PT J AU Gaillard, MK Giedt, J AF Gaillard, MK Giedt, J TI A D-moduli problem? SO PHYSICS LETTERS B LA English DT Article ID COSMOLOGICAL PROBLEMS; STRING THEORY; 4D STRINGS; SUPERGRAVITY; COUPLINGS; INFLATION AB We point out a generic problem in string-inspired supergravity models with an anomalous U(1)(X). A large number of matter multiplets charged under U(1)(X) remain massless above the supersymmetry-breaking scale because of degeneracy of vacua solving the D-flatness conditions. A toy model is analyzed as an illustration of the mechanism; we find the surprising result that many scalars remain massless after supersymmetry-breaking in a hidden sector. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RP Gaillard, MK (reprint author), Univ Calif Berkeley, Dept Phys, 50A-5101, Berkeley, CA 94720 USA. NR 14 TC 26 Z9 26 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 APR 20 PY 2000 VL 479 IS 1-3 BP 308 EP 314 DI 10.1016/S0370-2693(00)00336-1 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 310BP UT WOS:000086806900038 ER PT J AU Sieger, MT Orlando, TM AF Sieger, MT Orlando, TM TI Incident beam diffraction in electron stimulated desorption SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 8th International Workshop on Desorption Induced by Electronic Transitions CY SEP 27-OCT 01, 1999 CL LONG BRANCH, NEW JERSEY SP Army Res Off, Durham, Natl Sci Fdn, Ruters Lab Surface Modificat DE chlorine; electron-solid diffraction; electron-solid interactions; electron stimulated desorption (ESD); silicon ID SURFACE; SCATTERING; EMISSION; SPECTROSCOPY; SI(111)-7X7; MOLECULES; EJECTION AB We describe a new experimental technique utilizing incident beam diffraction in electron stimulated desorption (ESD) to determine the initial atomic bonding structure of desorbates. Diffraction in ESD can provide detailed information about the ground stale surface bonding geometry of the absorber with sub-angstrom resolution of bond vectors. We discuss the role of electron diffraction in ESD, and demonstrate these ideas with experimental measurements of Cl+ ion ESD from chlorinated Si(111)-(7 x 7) and (1 x 1) surfaces. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Sieger, MT (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, POB 999,MSIN K8-88, Richland, WA 99352 USA. RI Sieger, Matthew/B-4261-2011 OI Sieger, Matthew/0000-0001-7387-3660 NR 24 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 20 PY 2000 VL 451 IS 1-3 BP 31 EP 40 DI 10.1016/S0039-6028(00)00005-4 PG 10 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 308ZG UT WOS:000086742300006 ER PT J AU Feulner, P Romberg, R Frigo, SP Weimar, R Gsell, M Ogurtsov, A Menzel, D AF Feulner, P Romberg, R Frigo, SP Weimar, R Gsell, M Ogurtsov, A Menzel, D TI Recent progress in the investigation of core hole-induced photon stimulated desorption from adsorbates: excitation site-dependent bond breaking, and charge rearrangement SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 8th International Workshop on Desorption Induced by Electronic Transitions CY SEP 27-OCT 01, 1999 CL LONG BRANCH, NJ SP Army Res Off, Durham, Natl Sci Fdn, Ruters Lab Surface Modificat DE carbon monoxide; copper; desorption induced by electronic transitions (DIET); nitrogen atom; photon stimulated desorption (PSD); ruthenium; surface photochemistry ID SHELL PHOTOABSORPTION SPECTRA; AB-INITIO CALCULATIONS; AUGER RESONANT RAMAN; LEVEL SHIFTS; EXCITED-STATES; ION DESORPTION; METAL-SURFACES; N-2; SPECTROSCOPY; DISSOCIATION AB We report photon stimulated desorption (PSD) of neutral and ionic molecules and atoms from CO chemisorbed on Ru(001) and Cu(111), and from N(2) chemisorbed on Ru(001). Comparing branching ratios and spectral features for the O1s and N1s regions, we demonstrate that desorbing neutrals and ions are supplementary probes for the entire region of one- and multi-electron excitations, bearing valuable information on the transfer of energy and charge. For the primary [N1s]pi* excitation of N(2)/Ru(001), we find excitation site-dependent branching into desorption of N(2)(0), N(0) and N(+). PSD of neutral N atoms predominates for excitations of the N atom close to the surface, whereas mainly neutral N(2) molecules and N(+) ions are ejected for excitations of the outer N atom. At the Ru 3p substrate thresholds we find significant enhancements of the N(+) and N(2+) yields from N(2)/Ru(001), and discuss the electronic nature of the underlying energy transfer mechanism. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Tech Univ Munich, D-85747 Garching, Germany. Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. Verkin Inst Low Temp Phys & Engn, UA-310164 Kharkov, Ukraine. RP Feulner, P (reprint author), Tech Univ Munich, Phys Dept E 20, D-85747 Garching, Germany. RI Ogurtsov, Alexander/A-9601-2016; OI Ogurtsov, Alexander/0000-0003-4688-6428; Menzel, Dietrich/0000-0002-7188-8532 NR 45 TC 25 Z9 25 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 APR 20 PY 2000 VL 451 IS 1-3 BP 41 EP 52 DI 10.1016/S0039-6028(00)00006-6 PG 12 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 308ZG UT WOS:000086742300007 ER PT J AU Sieger, MT Orlando, TM AF Sieger, MT Orlando, TM TI Probing low-temperature water ice phases using electron-stimulated desorption SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 8th International Workshop on Desorption Induced by Electronic Transitions CY SEP 27-OCT 01, 1999 CL LONG BRANCH, NEW JERSEY SP Army Res Off, Durham, Natl Sci Fdn, Ruters Lab Surface Modificat DE crystalline-amorphous interfaces; crystallization; electron stimulated desorption (ESD); polycrystalline surfaces; water ID AMORPHOUS SOLID WATER; MOLECULAR-SURFACE STRUCTURE; D2O ICE; FILMS; CRYSTALLIZATION; MORPHOLOGY; ATTACHMENT; ENERGY; INDEX; D+ AB Low-energy electron-stimulated desorption (ESD) of D+ from D2O has been used to examine the phase and growth behavior of nanoscale vapor-deposited ice films grown on Pt(111) between 90-155 K. The D+ yield from porous amorphous solid water (deposited at 90 K) shows evidence for sintering near 120 K, increases between 120 and 140 K, and then drops at the amorphous-crystalline phase transition near 155 K. Ice deposited at 155 K forms an epitaxial crystalline film, with a D+ yield nearly one-third larger than the yield from crystalline films prepared by annealing the amorphous phase. This suggests that the film formed by annealing may have a different crystalline ordering or morphology than the epitaxial film deposited between 150 and 155 K. Ice deposited at 90 K on top of the epitaxial film is amorphous, but it crystallizes to a form similar to that of the underlying crystalline ice substrate. This suggests that, in this case, the buried two-dimensional interface nucleates the crystallization. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Orlando, TM (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, MS K8-88,POB 999, Richland, WA 99352 USA. RI Sieger, Matthew/B-4261-2011 OI Sieger, Matthew/0000-0001-7387-3660 NR 23 TC 13 Z9 13 U1 2 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 20 PY 2000 VL 451 IS 1-3 BP 97 EP 101 DI 10.1016/S0039-6028(00)00013-3 PG 5 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 308ZG UT WOS:000086742300014 ER PT J AU Romberg, R Frigo, SP Ogurtsov, A Feulner, P Menzel, D AF Romberg, R Frigo, SP Ogurtsov, A Feulner, P Menzel, D TI Photon stimulated desorption of neutral hydrogen atoms from condensed water and ammonia by resonant Ols and Nls excitation: search for the signature of ultrafast bond breaking SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 8th International Workshop on Desorption Induced by Electronic Transitions CY SEP 27-OCT 01, 1999 CL LONG BRANCH, NJ SP Army Res Off, Durham, Natl Sci Fdn, Ruters Lab Surface Modificat DE ammonia; desorption induced by electronic transitions (DIET); photon stimulated desorption (PSD); ruthenium; surface photochemistry; water ID CORE-LEVEL EXCITATION; SYNCHROTRON-RADIATION; HIGH-RESOLUTION; SHELL EXCITATION; AUGER DECAY; K-EDGE; SPECTROSCOPY; DISSOCIATION; HCL; ABSORPTION AB A highly sensitive detector for neutral particles has been designed and applied to photon stimulated desorption from condensed NH(3), and adsorbed and condensed H(2)O. Results on repulsive N1s and O1s core-to-bound excitations are reported, which for the isolated molecules are expected to stimulate ultrafast bond breaking and predominant emission of neutral H atoms. For NH(3) and H(2)O molecules on surfaces, strong H-atom signals are obtained for the entire O1s and N1s excitation energy range, but no selective enhancement due to ultrafast dissociation, although the previously observed enhancement of H(+) emission is well reproduced. Possible matrix effects are discussed as an explanation for this contrasting behavior of isolated and adsorbed/condensed molecules. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Tech Univ Munich, D-85747 Garching, Germany. Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. Verkin Inst Low Temp Phys & Engn, UA-310164 Kharkov, Ukraine. RP Romberg, R (reprint author), Tech Univ Munich, Physikdept E 20, D-85747 Garching, Germany. RI Ogurtsov, Alexander/A-9601-2016; OI Ogurtsov, Alexander/0000-0003-4688-6428; Menzel, Dietrich/0000-0002-7188-8532 NR 28 TC 33 Z9 33 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 20 PY 2000 VL 451 IS 1-3 BP 116 EP 123 DI 10.1016/S0039-6028(00)00016-9 PG 8 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 308ZG UT WOS:000086742300017 ER PT J AU Weimar, R Romberg, R Frigo, SP Kassuhlke, B Feulner, P AF Weimar, R Romberg, R Frigo, SP Kassuhlke, B Feulner, P TI Time-of-flight techniques for the investigation of kinetic energy distributions of ions and neutrals desorbed by core excitations SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 8th International Workshop on Desorption Induced by Electronic Transitions CY SEP 27-OCT 01, 1999 CL LONG BRANCH, NEW JERSEY SP Army Res Off, Durham, Natl Sci Fdn, Ruters Lab Surface Modificat DE carbon monoxide; desorption induced by electronic transitions (DIET); ion emission; photon stimulated desorption (PSD); ruthenium; surface photochemistry ID SURFACES; SPECTRA AB We present simple devices operating on the basis of mass spectrometers and time-of-flight techniques for the detection of kinetic energy distributions of neutrals and ions desorbed by photon excitation from adsorbates. We use data on photon stimulated desorption of O+ and O-0 from chemisorbed monolayers of CO to demonstrate the capabilities of our instruments. Different trends of the kinetic energy distributions as a function of the photon energy are revealed for the two species and explained on the basis of previously obtained results. The future potential of the methods is discussed. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Tech Univ Munich, D-85747 Garching, Germany. Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RP Weimar, R (reprint author), Tech Univ Munich, Physikdept E 20, D-85747 Garching, Germany. NR 12 TC 17 Z9 17 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 20 PY 2000 VL 451 IS 1-3 BP 124 EP 129 DI 10.1016/S0039-6028(00)00017-0 PG 6 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 308ZG UT WOS:000086742300018 ER PT J AU Beck, KM Joly, AG Hess, WP AF Beck, KM Joly, AG Hess, WP TI Time-resolved femtosecond laser-induced desorption from magnesium oxide and lithium fluoride single crystals SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 8th International Workshop on Desorption Induced by Electronic Transitions CY SEP 27-OCT 01, 1999 CL LONG BRANCH, NEW JERSEY SP Army Res Off, Durham, Natl Sci Fdn, Ruters Lab Surface Modificat DE laser methods; magnesium oxide; radiation damage; single crystal surfaces ID POSITIVE-ION EMISSION; SURFACE; MGO; EXCITATION; BULK; RADIATION; STATES; CO; NO AB We have used the pump-probe technique to measure the photostimulated positive-ion yield, as a function of time delay, between two ultraviolet laser pulses. We find that the ion yield from 265 nm femtosecond-irradiated MgO and LiF depends critically on the laser pulse delay in two-pulse correlation experiments. For example, single-pulse excitation of MgO produces a variety of ions including Mg+, MgO+ and H+. If the femtosecond laser pulse is split into two sub-threshold beams and then recombined with a variable time delay, the Mg+ desorption yield displays three distinct time regimes and persists for laser delays of over 100 ps. A pulse delay of only 500 fs nearly eliminates ion desorption except for Mg+. In contrast, the Li+ desorption yield from LiF decays more rapidly, largely within the femtosecond pulse duration. A weak but measurable decay component of approximately 2 ps is indicated, however. We hypothesize that non-resonant excitation contributes to the ultrafast desorption mechanism, possibly through the creation of surface electron-hole pairs and allows direct observation of the surface dynamics. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Hess, WP (reprint author), Pacific NW Natl Lab, POB 999, Richland, WA 99352 USA. NR 28 TC 7 Z9 7 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 20 PY 2000 VL 451 IS 1-3 BP 166 EP 173 DI 10.1016/S0039-6028(00)00023-6 PG 8 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 308ZG UT WOS:000086742300024 ER PT J AU Wirtz, L Hayderer, G Lemell, C Burgdorfer, J Hagg, L Reinhold, CO Varga, P Winter, P Aumayr, F AF Wirtz, L Hayderer, G Lemell, C Burgdorfer, J Hagg, L Reinhold, CO Varga, P Winter, P Aumayr, F TI Curve-crossing analysis for potential sputtering of insulators SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 8th International Workshop on Desorption Induced by Electronic Transitions CY SEP 27-OCT 01, 1999 CL LONG BRANCH, NJ SP Army Res Off, Durham, Natl Sci Fdn, Ruters Lab Surface Modificat DE insulating surfaces; sputtering ID HIGHLY-CHARGED IONS; ALKALI-HALIDES; LIF; SURFACES; NEUTRALIZATION; MICROBALANCE; UV AB We develop a theoretical model for the recently observed threshold for potential sputtering of LiF by slow singly and doubly charged ions. The threshold coincides with the potential energy to create a cold hole in the valence band of LiF by resonant neutralization. We calculate the level shift of the incident ion and the deformation of the valence band under the influence of the projectile. Resonant neutralization becomes possible for ions with recombination energies larger than 10 eV in agreement with the experimental findings. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Vienna Univ Technol, Inst Allgemeine Phys, A-1040 Vienna, Austria. Vienna Univ Technol, Inst Theoret Phys, A-1040 Vienna, Austria. Mid Sweden Univ, Dept Math & Phys, S-85170 Sundsvall, Sweden. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Aumayr, F (reprint author), Vienna Univ Technol, Inst Allgemeine Phys, Wiedner Hauptstr 8-10, A-1040 Vienna, Austria. EM aumayr@iap.tuwien.ac.at RI Lemell, Christoph/B-5147-2009; Varga, Peter/K-6377-2013; Aumayr, Friedrich/A-3920-2009; OI Lemell, Christoph/0000-0003-2560-4495; Aumayr, Friedrich/0000-0002-9788-0934; Reinhold, Carlos/0000-0003-0100-4962 NR 23 TC 9 Z9 9 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 20 PY 2000 VL 451 IS 1-3 BP 197 EP 202 DI 10.1016/S0039-6028(00)00027-3 PG 6 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 308ZG UT WOS:000086742300028 ER PT J AU Alexandrov, A Piacentini, M Tonkyn, RG Sieger, MT Zema, N Orlando, TM AF Alexandrov, A Piacentini, M Tonkyn, RG Sieger, MT Zema, N Orlando, TM TI Electron-stimulated desorption of iodine atoms from KI(100): an energy- and temperature-dependent study SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 8th International Workshop on Desorption Induced by Electronic Transitions CY SEP 27-OCT 01, 1999 CL LONG BRANCH, NEW JERSEY SP Army Res Off, Durham, Natl Sci Fdn, Ruters Lab Surface Modificat DE electron stimulated desorption (ESD) ID NONTHERMAL HALOGEN ATOMS; ALKALI-HALIDES; EMISSION; SURFACES; EXCITATION; PHOTODESORPTION; DISTRIBUTIONS; BOMBARDMENT; MECHANISM; NACL AB We have studied the electron-stimulated desorption (ESD) of neutral atomic iodine from single crystals of KI(100) using time-of-flight laser-resonance-enhanced multiphoton ionization spectroscopy and quadrupole mass spectrometry. The measured iodine velocity distributions have thermal and non-thermal components. The yield of the thermal component increases with increasing substrate temperature, whereas the yield of the non-thermal component decreases slightly with temperature. The ESD rate for the thermal component decreases with increasing pulse width, unlike the rate for the non-thermal component, which is independent of pulse width. Measurements of ESD yields versus incident electron energy indicate a threshold of similar to 5.5 eV. The data collectively indicate that ESD of KI involves exciton decay at the surface. The temperature and pulse-width dependencies of the thermal component are consistent with decay of bulk self-trapped excitons, thermally assisted H-center diffusion and trapping at metastable defects. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Pacific NW Natl Lab, WR Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. Univ Rome La Sapienza, Dipartimento Energet, Rome, Italy. INFM, Unita Roma 1, Rome, Italy. CNR, Ist Struttura Mat, Area Ric, Rome, Italy. RP Orlando, TM (reprint author), Pacific NW Natl Lab, WR Wiley Environm Mol Sci Lab, POB 999,MSIN K8-88, Richland, WA 99352 USA. RI Sieger, Matthew/B-4261-2011; OI Sieger, Matthew/0000-0001-7387-3660; Zema, Nicola/0000-0003-2705-6146 NR 21 TC 10 Z9 10 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 20 PY 2000 VL 451 IS 1-3 BP 208 EP 213 DI 10.1016/S0039-6028(00)00029-7 PG 6 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 308ZG UT WOS:000086742300030 ER PT J AU Kronenberg, AK Castaing, J Mitchell, TE Kirby, SH AF Kronenberg, AK Castaing, J Mitchell, TE Kirby, SH TI Hydrogen defects in alpha-Al2O3 and water weakening of sapphire and alumina ceramics between 600 and 1000 degrees C - I. - Infrared characterization of defects SO ACTA MATERIALIA LA English DT Article DE annealing; infrared spectroscopy; structural ceramics; diffusion; lattice defects ID SINGLE-CRYSTALS; DIFFUSION; QUARTZ; ABSORPTION; DEUTERONS; CORUNDUM; PROTONS; COLOR; OXIDE AB Hydrogen impurities in materials influence their properties, including flow strength, alpha-Al2O3 single crystals and polycrystalline ceramics were annealed in supercritical water between 850 and 1025 degrees C, under pressures in the range 1500-2000 MPa. A few specimens were further subjected to plastic deformation. Hydrogen penetration was examined using infrared absorption measurements of O-H bond vibrations, which revealed two kinds of hydrogen defects. In single crystals, defects are characterized by sharp O-H absorption bands assigned to interstitial protons. Hydrogen impurities of hydrothermally annealed ceramics and of all hydrothermally deformed specimens are characterized by broad O-H bands assigned to molecular water. The grain boundaries of hydrothermally annealed ceramics are severely damaged. The kinetics of hydrogen penetration is consistent with diffusion data. (C) 2000 Acta Metallurgica he. Published by Elsevier Science Ltd. All rights reserved. C1 Univ Sevilla, Dept Fis Mat Condensada, Seville 41080, Spain. Texas A&M Univ, Dept Geol & Geophys, Ctr Tectonophys, College Stn, TX 77843 USA. Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. US Geol Survey, Menlo Park, CA 94025 USA. C2RMF, LRMF, CNRS, UNR 171, F-75041 Paris 01, France. RP Castaing, J (reprint author), Univ Sevilla, Dept Fis Mat Condensada, Apartado 1065, Seville 41080, Spain. NR 37 TC 29 Z9 29 U1 4 U2 15 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD APR 19 PY 2000 VL 48 IS 7 BP 1481 EP 1494 DI 10.1016/S1359-6454(99)00448-6 PG 14 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 311EW UT WOS:000086872600006 ER PT J AU Castaing, J Kronenberg, AK Kirby, SH Mitchell, TE AF Castaing, J Kronenberg, AK Kirby, SH Mitchell, TE TI Hydrogen defects in alpha-Al2O3 and water weakening of sapphire and alumina ceramics between 600 and 1000 degrees C - II. - Mechanical properties SO ACTA MATERIALIA LA English DT Article DE stress-strain relationship measurements; structural ceramics; transmission electron microsopy (TEM); mechanical properties; dislocation mobility ID CRYSTALS; QUARTZ; SLIP AB Hydrogen impurities in alumina have been introduced by hydrothermal annealing (see part I). In this paper, we report on reductions in the Row strength of alpha-Al2O3 single crystals and polycrystals associated with hydrogen incorporation. Prior to deformation, alpha-Al2O3 single crystal and ceramic specimens were annealed in the presence of supercritical water at 850 degrees or 900 degrees C, under 1500 MPa pressure. Sapphire and alumina ceramics were plastically deformed between 600 degrees and 1000 degrees C under 1500 MPa pressure, by the addition of a uniaxial stress. Flow stresses are reduced by a factor of two, due to the presence of water, for sapphire and large grain (30-50 mu m) polycrystals, as a result of enhanced dislocation mobility. Flow stresses of fine-grained (3-5 mu m) polycrystals are reduced by water by a factor of six. This large reduction in strength is attributed to a change in mechanism from dislocation glide under dry conditions to grain boundary sliding under hydrothermal conditions. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. C1 Univ Sevilla, Dept Fis Mat Condensada, E-41080 Seville, Spain. CNRS, UMR 171, LRMF, Ctr Rech & REstaurat Musees France,C2RMF, F-75041 Paris 01, France. Texas A&M Univ, Dept Geol & Geophys, Ctr Tectonophys, College Stn, TX 77843 USA. US Geol Survey, Menlo Park, CA 94025 USA. Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. RP Castaing, J (reprint author), Univ Sevilla, Dept Fis Mat Condensada, Apartado 1065, E-41080 Seville, Spain. NR 20 TC 16 Z9 16 U1 1 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD APR 19 PY 2000 VL 48 IS 7 BP 1495 EP 1504 DI 10.1016/S1359-6454(99)00449-8 PG 10 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 311EW UT WOS:000086872600007 ER PT J AU Fessenden, RW Meisel, D Camaioni, DM AF Fessenden, RW Meisel, D Camaioni, DM TI Addition of oxide radical ions (O-) to nitrite and oxide ions (O2-) to nitrogen dioxide SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID ELECTRON-TRANSFER PROCESSES; AQUEOUS-SOLUTION; HYDRATED ELECTRONS; PULSE RADIOLYSIS; RATE CONSTANTS; WATER; ANION C1 Univ Notre Dame, Notre Dame Radiat Lab, Notre Dame, IN 46556 USA. Univ Notre Dame, Dept Chem & Biochem, Notre Dame, IN 46556 USA. Pacific NW Lab, Richland, WA 99352 USA. RP Camaioni, DM (reprint author), Univ Notre Dame, Notre Dame Radiat Lab, Notre Dame, IN 46556 USA. NR 26 TC 22 Z9 22 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 APR 19 PY 2000 VL 122 IS 15 BP 3773 EP 3774 DI 10.1021/ja994230t PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 308TT UT WOS:000086729500026 ER PT J AU Ahuja, D Vera, MD SirDeshpande, BV Morimoto, H Williams, PG Joullie, MM Toogood, PL AF Ahuja, D Vera, MD SirDeshpande, BV Morimoto, H Williams, PG Joullie, MM Toogood, PL TI Inhibition of protein synthesis by didemnin B: How EF-1 alpha mediates inhibition of translocation SO BIOCHEMISTRY LA English DT Article ID ANTIPROLIFERATIVE AGENT DIDEMNIN; ELONGATION-FACTOR 1-ALPHA; FACTOR TU; IN-VITRO; MECHANISM; COMPLEX; FACTOR-1-ALPHA; PROLIFERATION; THIOESTERASE; TRANSLATION AB The antineoplastic cyclic depsipeptide didemnin B (DB) inhibits protein synthesis in cells and in vitro. The stage at which DB inhibits protein synthesis in cells is not known, although dehydrodidemnin B arrests translation at the stage of polypeptide elongation. Inhibition of protein synthesis by DB in vitro also occurs at the elongation stage, and it was shown previously that DB prevents EF-2-dependent translocation in partial reaction models of protein synthesis. This inhibition of translocation displays an absolute requirement for EF-1 alpha; however, the dependence upon EF-1 alpha was previously unexplained. It is shown here that DB binds only weakly to EF-1 alpha/GTP in solution, but binds to ribosome.EF-1 alpha complexes with a dissociation constant K-d = 4 mu M.'Fhus, the inhibition of protein synthesis by DB appears to involve an interaction with both EF-1 alpha and ribosomes in which all three components are required. Using diphtheria toxin-mediated ADP-ribosylation to assay for EF-2, it is demonstrated that DB blocks EF-2 binding to pre-translocative ribosome EF-1 alpha complexes, thus preventing ribosomal translocation, Based on this model for protein synthesis inhibition by DB, and the proposed mechanism of action of fusidic acid, evidence is presented in support of the Grasmuk model for EF-1 alpha function in which this elongation factor does not fully depart the ribosome during polypeptide elongation. C1 Univ Michigan, Dept Chem, Willard H Dow Lab, Ann Arbor, MI 48109 USA. Univ Penn, Dept Chem, Philadelphia, PA 19104 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Natl Tritium Labeling Lab, Struct Biol Div, Berkeley, CA 94720 USA. RP Toogood, PL (reprint author), Warner Lambert Parke Davis, Parke Davis Pharmaceut Res, 2800 Plymouth Rd, Ann Arbor, MI 48105 USA. FU NCI NIH HHS [R29 CA619178, R01 CA40081] NR 50 TC 28 Z9 30 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 APR 18 PY 2000 VL 39 IS 15 BP 4339 EP 4346 DI 10.1021/bi992202h PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 304LB UT WOS:000086484200016 PM 10757982 ER PT J AU Chin, CJ Yiacoumi, S Tsouris, C Relle, S Grant, SB AF Chin, CJ Yiacoumi, S Tsouris, C Relle, S Grant, SB TI Secondary-minimum aggregation of superparamagnetic colloidal particles SO LANGMUIR LA English DT Article ID MAGNETIC FLUID; FLOCCULATION; FIELD; FLOW; DISPERSIONS; STABILITY; COAGULATION; MECHANISM; KINETICS; SPHERES AB This article investigates secondary-minimum aggregation of superparamagnetic colloidal latex particles. Chain formation and breakup are experimentally observed by using visualization techniques. The secondary minimum of the potential energy between two particles is determined from potential energy calculations, which include van der Waals, electrostatic, and magnetic dipole forces. A trajectory analysis, which incorporates these interparticle forces, hydrodynamic resistance forces, as well as gravity and magnetic induction forces, is also used to determine the secondary minimum. Furthermore, this study describes relative mobility functions caused by magnetic induction between two approaching particles. The effects of the following factors on the location of the secondary minimum are investigated: external magnetic field strength;particle size; and solution properties, such as ionic strength, zeta potential, and particle magnetic susceptibility. Both potential energy calculations and trajectory analysis lead to the same conclusion: the secondary-minimum separation decreases with increasing magnetic dipole force, decreasing electrostatic force, and increasing particle size and size ratio. After the removal of the magnetic field, three regimes of chain behavior may be identified: (i) no breakup regime, in which chains do not break, indicating primary-minimum aggregation; (ii) slow breakup regime; and (iii) fast breakup regime. Primary-minimum aggregation occurs when the chains are formed in high-ionic-strength solutions or at the pH of zero charge. Slow breakup occurs when the chains are formed under a low-strength magnetic field, while fast breakup occurs when the chains are formed under a high-strength magnetic field. C1 Georgia Inst Technol, Sch Civil & Environm Engn, Atlanta, GA 30332 USA. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. Univ Calif Irvine, Dept Civil & Environm Engn, Irvine, CA 92697 USA. RP Yiacoumi, S (reprint author), Georgia Inst Technol, Sch Civil & Environm Engn, Atlanta, GA 30332 USA. RI Tsouris, Costas/C-2544-2016; Grant, Stanley/K-8179-2016 OI Tsouris, Costas/0000-0002-0522-1027; Grant, Stanley/0000-0001-6221-7211 NR 34 TC 21 Z9 22 U1 1 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD APR 18 PY 2000 VL 16 IS 8 BP 3641 EP 3650 DI 10.1021/la991201n PG 10 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 304LA UT WOS:000086484100013 ER PT J AU Narula, CK Rokosz, M Allard, LF Kudla, RJ Chattha, MS AF Narula, CK Rokosz, M Allard, LF Kudla, RJ Chattha, MS TI Sol-gel processed silica-alumina materials for diesel engine emission reduction catalysts SO LANGMUIR LA English DT Article ID SELECTIVE REDUCTION; NITROGEN MONOXIDE; NITRIC-OXIDE; HYDROCARBONS; NOX AB The incorporation of > 30% silica in alumina prior to platinum impregnation improves the NOx conversion efficiency in the 200-300 degrees C range from 45 to 57% and reduces light-off temperature. Further increase in the amount of silica to 50% is detrimental to NOx conversion efficiency. The H-1 and Si-29 NMR of the materials suggest that this trend is probably related to the surface acidity. The analyses of these materials by X-ray powder diffraction and electron microscopy do not reveal significant differences. Additional NOx conversion in the 350-450 degrees C range with a maximum of 30% at 400 degrees C can be achieved if a rhodium-impregnated 30% silica-alumina, Rh-30% SiO2-Al2O3, is placed upstream of Pt-30% SiO2-Al2O3. it is important to note that mixing Pt-30% SiO2-Al2O3 with Rh-30%SiO2-Al2O3 does not enhance conversion efficiency or effective temperature range. C1 Ford Motor Co, Dept Chem, Dearborn, MI 48121 USA. Oak Ridge Natl Lab, High Temp Mat Lab, Oak Ridge, TN 37831 USA. Ford Motor Co, Dept Chem Engn, Dearborn, MI 48121 USA. RP Narula, CK (reprint author), Ford Motor Co, Dept Chem, MD 3083,POB 2053, Dearborn, MI 48121 USA. NR 27 TC 8 Z9 8 U1 1 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD APR 18 PY 2000 VL 16 IS 8 BP 3818 EP 3822 DI 10.1021/la991090s PG 5 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 304LA UT WOS:000086484100035 ER PT J AU Rallabandi, PS Thompson, AP Ford, DM AF Rallabandi, PS Thompson, AP Ford, DM TI A molecular modeling study of entropic and energetic selectivities in air separation with glassy polymers SO MACROMOLECULES LA English DT Article ID TRANSITION-STATE THEORY; FREE-VOLUME; DYNAMICS SIMULATION; GAS SEPARATION; ATACTIC POLYPROPYLENE; DENSE POLYMERS; DIFFUSION; MEMBRANES; PERMEABILITY; SILICALITE AB Air separation is challenging due to the similarities in the sizes and energetics of oxygen and nitrogen. Although polymer membrane-based technology has achieved some success in replacing conventional air separation methods, the effectiveness of polymers has been shown to fall short of the economically attractive region occupied by inorganic microporous materials. Koros and co-workers have recently proposed that this lack of performance is a manifestation of the low entropic selectivity in polymers, possibly due to chain mobility or free volume effects. In this work, we address the effects of chain mobility on selectivity using molecular models and transition-state theory. We employ the methodology recently developed;by Greenfield and Theodorou (Macromolecules 1998, 31, 7068) in which the polymer degrees of freedom can be explicitly included in the hopping rate calculations. About 100 oxygen and nitrogen jump events are studied in three different glassy polypropylene configurations. To examine the effects of polymer rigidity, two separate cases are considered for each jump; in the first case, the polymer model is held completely rigid during the event, while in the second the polymer torsional degrees of freedom are allowed to participate. The results show that the effects of polymer flexibility are reflected most significantly in the energy barriers, with the entropy barriers only marginally affected. Whereas the energetic selectivity can be reduced by 4 orders of magnitude in going from the rigid model to the flexible one, the entropic selectivity generally shows little change. The results are discussed in the context of current experimental and theoretical understanding of these systems. C1 Texas A&M Univ, Dept Chem Engn, College Stn, TX 77843 USA. Sandia Natl Labs, Computat Biol & Mat Technol Dept, Albuquerque, NM 87185 USA. RP Ford, DM (reprint author), Texas A&M Univ, Dept Chem Engn, College Stn, TX 77843 USA. RI Ford, David/C-4027-2008 NR 50 TC 7 Z9 7 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD APR 18 PY 2000 VL 33 IS 8 BP 3142 EP 3152 DI 10.1021/ma991599u PG 11 WC Polymer Science SC Polymer Science GA 307WG UT WOS:000086676700053 ER PT J AU Savvate'ev, V Friedl, J Zou, L Oldham, WJ Shinar, J AF Savvate'ev, V Friedl, J Zou, L Oldham, WJ Shinar, J TI Efficiency peaks in the transient electroluminescence of multilayer organic light-emitting devices SO APPLIED PHYSICS LETTERS LA English DT Article ID DIODES; EMISSION; CATHODE AB It is shown that when multilayer organic light-emitting devices (OLEDs) containing hole (h(+)) and electron (e(-)) transporting layers (HTLs and ETLs, respectively) are biased with microsecond to millisecond voltage pulses higher than a threshold value V-th, the electroluminescence (EL) intensity increases dramatically to a peak value which then relaxes to the lower dc value; the relaxation time decreases strongly with increasing pulse amplitude. Since the current waveforms are essentially rectangular, the transient EL is proportional to the external quantum efficiency eta. The value of V-th coincides with the bias for maximum dc efficiency typically observed when eta is monitored vs V. This relation and the apparent absence of the transient peak in single-layer OLEDs suggest that it is due either to internal field redistribution processes in the ETL and HTL or to space charges, e.g., trapped polarons which accumulate at the HTL/ETL interface, and quench the emitting singlet excitons. It is concluded that highly efficient OLED operation may be achieved at high brightness by pulsed bias at an optimized duty cycle. (C) 2000 American Institute of Physics. [S0003-6951(00)05616-3]. C1 Iowa State Univ Sci & Technol, Ames Lab, US DOE, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames, IA 50011 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Shinar, J (reprint author), Iowa State Univ Sci & Technol, Ames Lab, US DOE, Ames, IA 50011 USA. NR 15 TC 11 Z9 11 U1 3 U2 13 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 17 PY 2000 VL 76 IS 16 BP 2170 EP 2172 DI 10.1063/1.126287 PG 3 WC Physics, Applied SC Physics GA 302YG UT WOS:000086393600008 ER PT J AU Ahuja, R Eriksson, O Wills, JM Johansson, B AF Ahuja, R Eriksson, O Wills, JM Johansson, B TI Electronic structure of Ti3SiC2 SO APPLIED PHYSICS LETTERS LA English DT Article ID BRILLOUIN-ZONE; SPECIAL POINTS; SYSTEMS; BAND AB We have investigated the electronic structure of Ti3SiC2 by means of first-principles self-consistent total-energy calculations within the local-density approximation using the full-potential linear-muffin-tin-orbital method. Our calculated volume is in good agreement (within 4%) with experiment. Also, the calculated values for c/a and positional parameters are in excellent agreement with the experimental data. We have compared the electronic structure of Ti3SiC2 with TiC. Our calculations show that Ti3SiC2 has a chemical bonding similar to the one of TiC, which is predominantly covalent. (C) 2000 American Institute of Physics. [S0003-6951(00)01716-2]. C1 Univ Uppsala, Dept Phys, Condensed Matter Theory Grp, S-75121 Uppsala, Sweden. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Ahuja, R (reprint author), Univ Uppsala, Dept Phys, Condensed Matter Theory Grp, S-75121 Uppsala, Sweden. RI Eriksson, Olle/E-3265-2014 OI Eriksson, Olle/0000-0001-5111-1374 NR 20 TC 51 Z9 52 U1 1 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 17 PY 2000 VL 76 IS 16 BP 2226 EP 2228 DI 10.1063/1.126304 PG 3 WC Physics, Applied SC Physics GA 302YG UT WOS:000086393600027 ER PT J AU Chang, PC Baca, AG Li, NY Xie, XM Hou, HQ Armour, E AF Chang, PC Baca, AG Li, NY Xie, XM Hou, HQ Armour, E TI InGaP/InGaAsN/GaAs NpN double-heterojunction bipolar transistor SO APPLIED PHYSICS LETTERS LA English DT Article ID TEMPERATURE AB We have demonstrated a functional NpN double-heterojunction bipolar transistor (DHBT) using InGaAsN for the base layer. The InGaP/In0.03Ga0.97As0.99N0.01/GaAs DHBT has a low V-ON of 0.81 V, which is 0.13 V lower than in a InGaP/GaAs heterojunction bipolar transistor (HBT). The lower turn-on voltage is attributed to the smaller band gap (1.20 eV) of metalorganic chemical vapor deposition-grown In0.03Ga0.97As0.99N0.01 base layer. GaAs is used for the collector; thus the breakdown voltage (BVCEO) is 10 V, consistent with the BVCEO of InGaP/GaAs HBTs of comparable collector thickness and doping level. To alleviate the current blocking phenomenon caused by the larger conduction band discontinuity between InGaAsN and GaAs, a graded InGaAs layer with delta doping is inserted at the base-collector junction. The improved device has a peak current gain of seven with ideal current-voltage characteristics. (C) 2000 American Institute of Physics. [S0003-6951(00)02116-1]. C1 Sandia Natl Labs, Albuquerque, NM 87123 USA. EMCORE Corp, EMCORE Photovolta, Albuquerque, NM 87123 USA. EMCORE Corp, Somerset, NJ 08873 USA. RP Chang, PC (reprint author), Sandia Natl Labs, Albuquerque, NM 87123 USA. NR 12 TC 51 Z9 53 U1 3 U2 9 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 17 PY 2000 VL 76 IS 16 BP 2262 EP 2264 DI 10.1063/1.126315 PG 3 WC Physics, Applied SC Physics GA 302YG UT WOS:000086393600039 ER PT J AU Sigalas, MM Garcia, N AF Sigalas, MM Garcia, N TI Importance of coupling between longitudinal and transverse components for the creation of acoustic band gaps: The aluminum in mercury case SO APPLIED PHYSICS LETTERS LA English DT Article ID PERIODIC ELASTIC COMPOSITES; SOUND-ATTENUATION; CYLINDERS; WAVES AB Using the finite-difference time-domain method, we theoretically study elastic waves propagating in a two-dimensional composite consisting of aluminum cylinders embedded in mercury. The importance of the transverse components of the aluminum scatterers in the creation of the gaps is shown by switching off the transverse waves inside the aluminum. In that case, there are very narrow gaps or no gaps at all. In contrast, when the transverse components are on, as they should be, wide full band gaps appear for longitudinal incident waves. Since mercury supports only longitudinal waves, these are full elastic band gaps. (C) 2000 American Institute of Physics. [S0003-6951(00)03116-8]. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. CSIC, Lab Fis Sistemas Pequenos & Nanotecnol, E-28006 Madrid, Spain. RP Sigalas, MM (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 18 TC 44 Z9 44 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 17 PY 2000 VL 76 IS 16 BP 2307 EP 2309 DI 10.1063/1.126328 PG 3 WC Physics, Applied SC Physics GA 302YG UT WOS:000086393600054 ER PT J AU Yeo, IH Johnson, DC AF Yeo, IH Johnson, DC TI Anodic response of glucose at copper-based alloy electrodes SO JOURNAL OF ELECTROANALYTICAL CHEMISTRY LA English DT Article DE glucose; oxidation; Cu alloys; voltammetry; rotated electrodes ID POTENTIAL AMPEROMETRIC DETECTION; ALKALINE MEDIA; CAPILLARY ELECTROPHORESIS; DISSOLUTION; OXIDATION AB The anodic response of glucose is compared for three Cu-based alloy electrodes (Ni10Cu90, Fe3Cu97 and Mn5Cu95) with that observed for a pure Cu electrode in the approximate potential region 0.00-0.80 V versus SCE in 0.10 M NaOH. Only the response at the Ni10Cu90 electrode is concluded to involve a redox-mediated mechanism based on voltammetric evidence for a surface redox process in the potential region of glucose response. The anodic response for glucose at the Mn5Cu95 electrode is significantly larger than that obtained for the other electrodes. This larger sensitivity at the Mn5Cu95 electrode is attributed to the kinetic benefit that results from preadsorption of glucose molecules at Mn-sites at the surface of the oxide-covered alloy electrode. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, US DOE, Ames, IA 50011 USA. RP Johnson, DC (reprint author), Iowa State Univ, Dept Chem, 3751 Gilman Hall, Ames, IA 50011 USA. NR 24 TC 51 Z9 52 U1 0 U2 6 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0022-0728 J9 J ELECTROANAL CHEM JI J. Electroanal. Chem. PD APR 17 PY 2000 VL 484 IS 2 BP 157 EP 163 DI 10.1016/S0022-0728(00)00072-3 PG 7 WC Chemistry, Analytical; Electrochemistry SC Chemistry; Electrochemistry GA 327VE UT WOS:000087814100008 ER PT J AU Chialvo, AA Kusalik, PG Cummings, PT Simonson, JM Mesmer, RE AF Chialvo, AA Kusalik, PG Cummings, PT Simonson, JM Mesmer, RE TI Molecular approach to high-temperature solvation. Formal, integral equation and experimental results SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 4th EPS Liquid Matter Conference CY JUL 03-07, 1999 CL GRANADA, SPAIN SP EPS ID HYPERNETTED-CHAIN APPROXIMATION; AQUEOUS-ELECTROLYTE SOLUTIONS; PARTIAL MOLAR VOLUMES; INFINITE DILUTION; MIXTURES; SIMULATION; MODELS; LICL; NACL; NABR AB The solvation of infinitely dilute CsBr in high-temperature aqueous solutions is analysed by integral equation calculations, according to the recently proposed molecular-based formalism which connects the solvent environment around individual ionic species and their macroscopic solvation behaviour. Recent experimental data for infinitely dilute CsBr aqueous solutions are interpreted via the same formalism and compared with their analogous integral equation calculations. Finally, some relevant theoretical implications regarding the modelling of high-temperature aqueous electrolyte solutions are discussed and illustrated by integral equation results. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Chem Engn, Knoxville, TN 37996 USA. Dalhousie Univ, Dept Chem, Halifax, NS B3H 4J3, Canada. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Chem Engn Chem & Comp Sci, Knoxville, TN 37996 USA. RP Chialvo, AA (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, POB 2008, Oak Ridge, TN 37831 USA. RI Cummings, Peter/B-8762-2013; OI Cummings, Peter/0000-0002-9766-2216; Chialvo, Ariel/0000-0002-6091-4563 NR 28 TC 11 Z9 11 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD APR 17 PY 2000 VL 12 IS 15 BP 3585 EP 3593 DI 10.1088/0953-8984/12/15/307 PG 9 WC Physics, Condensed Matter SC Physics GA 309TE UT WOS:000086784700011 ER PT J AU Daniel, M Budnick, JI Hines, WA Zhang, YD Clark, WG Moodenbaugh, AR AF Daniel, M Budnick, JI Hines, WA Zhang, YD Clark, WG Moodenbaugh, AR TI Nuclear magnetic resonance study of polycrystalline Sr1-xCaxRuO3 (0 <= x <= 1.0) SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID SRRUO3; SUPERCONDUCTIVITY; TRANSPORT; CARUO3; LA AB A zero-field spin-echo nuclear magnetic resonance (NMR) study of Ru-99,Ru-101 nuclei in polycrystalline powder samples of magnetically ordered Sr1-xCaxRuO3 (0 less than or equal to x less than or equal to 1.0) is reported. The NMR spectrum for SrRuO3 at 1.3 K consists of two peaks at 64.4 MHz and 72.2 MHz corresponding to the Ru-99 and Ru-101 isotopes, respectively, and a hyperfine field of 329 kG. With the replacement of Sr by Ca, the peaks broaden somewhat, although there is essentially no change in the peak frequencies. However, the two resonance peaks show a significant reduction in height with intensity being shifted into the wings. Although electric quadrupole effects are present, the results suggest that the reduction of peak intensity when Ca is added is due mainly to a progressive loss of Ru moments participating in the magnetic ordering. The loss is a consequence of the dilution of the ferromagnetic exchange coupling between the moments. A measure of the spontaneous magnetization temperature dependence for SrRuO3 (less than or equal to 21 K) has been obtained from the shift of the peak frequencies. It was found that the spontaneous magnetization decreases with a Bloch law T-3/2 temperature dependence characteristic of spin-wave excitations. From the coefficient of the temperature dependence, a value of 2.4 meV was obtained for the exchange integral which is consistent with the observed ordering temperature. C1 Univ Connecticut, Dept Phys, Storrs, CT 06269 USA. Univ Connecticut, Inst Mat Sci, Storrs, CT 06269 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11977 USA. RP Daniel, M (reprint author), Univ Connecticut, Dept Phys, Storrs, CT 06269 USA. NR 25 TC 11 Z9 11 U1 1 U2 6 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD APR 17 PY 2000 VL 12 IS 16 BP 3857 EP 3869 DI 10.1088/0953-8984/12/16/308 PG 13 WC Physics, Condensed Matter SC Physics GA 314QD UT WOS:000087066300009 ER PT J AU Dodelson, S Knox, L AF Dodelson, S Knox, L TI Dark energy and the cosmic microwave background radiation SO PHYSICAL REVIEW LETTERS LA English DT Article ID GRAVITATIONAL LENS PG-1115+080; GALAXY CLUSTERS; ANISOTROPY; UNIVERSE; MODELS AB We find that current cosmic microwave background anisotropy data strongly constrain the mean spatial curvature of the Universe to be near zero, or, equivalently, the total energy density to be near critical-as predicted by inflation. This result is robust to editing of data sets, and variation of other cosmological parameters (totaling seven, including a cosmological constant). Other lines of argument indicate that the energy density of nonrelativistic matter is much less than critical. Together, these results are evidence, independent of supernovae data, for dark energy in the Universe. C1 Fermi Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. RP Dodelson, S (reprint author), Fermi Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. NR 63 TC 92 Z9 92 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 17 PY 2000 VL 84 IS 16 BP 3523 EP 3526 DI 10.1103/PhysRevLett.84.3523 PG 4 WC Physics, Multidisciplinary SC Physics GA 304VH UT WOS:000086504500005 PM 11019136 ER PT J AU Reiter, P Khoo, TL Lauritsen, T Lister, CJ Seweryniak, D Sonzogni, AA Ahmad, I Amzal, N Bhattacharyya, P Butler, PA Carpenter, MP Chewter, AJ Cizewski, JA Davids, CN Ding, KY Fotiades, N Greene, JP Greenlees, PT Heinz, A Henning, WF Herzberg, RD Janssens, RVF Jones, GD Kankaanpaa, H Kondev, FG Korten, W Leino, M Siem, S Uusitalo, J Vetter, K Wiedenhover, I AF Reiter, P Khoo, TL Lauritsen, T Lister, CJ Seweryniak, D Sonzogni, AA Ahmad, I Amzal, N Bhattacharyya, P Butler, PA Carpenter, MP Chewter, AJ Cizewski, JA Davids, CN Ding, KY Fotiades, N Greene, JP Greenlees, PT Heinz, A Henning, WF Herzberg, RD Janssens, RVF Jones, GD Kankaanpaa, H Kondev, FG Korten, W Leino, M Siem, S Uusitalo, J Vetter, K Wiedenhover, I TI Entry distribution, fission barrier, and formation mechanism of No-254(102) SO PHYSICAL REVIEW LETTERS LA English DT Article ID ELEMENTS; NUCLEI AB The entry distribution in angular momentum and excitation energy for the formation of No-254 has been measured after the Pb-208(Ca-48,2n) reaction at 215 and 219 MeV. This nucleus is populated up to spin 22h and excitation energy greater than or similar to 6 MeV above the yrast line, with the half-maximum points of the energy distributions at similar to 5 MeV for spins between 12h and 22h. This suggests that the fission barrier is greater than or similar to 5 MeV and that the shell-correction energy persists to high spin. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Univ Munich, D-85748 Garching, Germany. Univ Liverpool, Liverpool L69 7ZE, Merseyside, England. Purdue Univ, W Lafayette, IN 47907 USA. Rutgers State Univ, New Brunswick, NJ 08903 USA. CEA Saclay, DAPNIA SPhN, F-91191 Gif Sur Yvette, France. Univ Jyvaskyla, Jyvaskyla, Finland. Univ Oslo, Oslo, Norway. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Reiter, P (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Herzberg, Rolf-Dietmar/E-1558-2011; KORTEN, Wolfram/H-3043-2013; Heinz, Andreas/E-3191-2014; Carpenter, Michael/E-4287-2015; OI Carpenter, Michael/0000-0002-3237-5734; KORTEN, Wolfram/0000-0002-3940-0816; Butler, Peter/0000-0001-6080-9205 NR 24 TC 102 Z9 103 U1 0 U2 6 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 APR 17 PY 2000 VL 84 IS 16 BP 3542 EP 3545 DI 10.1103/PhysRevLett.84.3542 PG 4 WC Physics, Multidisciplinary SC Physics GA 304VH UT WOS:000086504500010 ER PT J AU Russina, M Mezei, E Lechner, R Longeville, S Urban, B AF Russina, M Mezei, E Lechner, R Longeville, S Urban, B TI Experimental evidence for fast heterogeneous collective structural relaxation in a supercooled liquid near the glass transition SO PHYSICAL REVIEW LETTERS LA English DT Article ID DYNAMIC CORRELATIONS AB We have extended the exploration of microscopic dynamics of supercooled liquids to small wave numbers Q corresponding to the scale of intermediate range order. by developing a new experimental approach for precise data correction for multiple scattering noise in inelastic coherent neutron scattering. Our results in supercooled Ca0.4K0.6(NO3)(1.4) reveal the first direct experimental evidence, after a decade of controversy, that the so-called picosecond process around the glass transition corresponds to a predicted first, faster stage of the structural relaxation. Ln addition, they show that this process takes the spatial form of fast heterogeneous collective flow of correlated groups of atoms. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Hahn Meitner Inst Kernforsch Berlin GmbH, D-14109 Berlin, Germany. RP Russina, M (reprint author), Univ Calif Los Alamos Natl Lab, MS H805, Los Alamos, NM 87545 USA. RI Russina, Margarita/E-9886-2016 OI Russina, Margarita/0000-0003-2067-606X NR 18 TC 47 Z9 48 U1 2 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 APR 17 PY 2000 VL 84 IS 16 BP 3630 EP 3633 DI 10.1103/PhysRevLett.84.3630 PG 4 WC Physics, Multidisciplinary SC Physics GA 304VH UT WOS:000086504500032 ER PT J AU Cho, JH Zhang, SB Zunger, A AF Cho, JH Zhang, SB Zunger, A TI Indium-indium pair correlation and surface segregation in InGaAs alloys SO PHYSICAL REVIEW LETTERS LA English DT Article ID SEMICONDUCTOR ALLOYS; PSEUDOPOTENTIALS; HETEROSTRUCTURES; RECONSTRUCTIONS; SUPERLATTICES; MODULATION; GAS AB In-In pair correlations and In surface segregation in InxGa1-xAs alloys are studied by first-principles total-energy calculations. By calculating the substitution energy of a single In atom, we find that the nearsurface energetics explains the observed In segregation on InGaAs(001)-beta 2(2 X 4) surfaces. Indium surface segregation further enhances the In site selectivity, thus the long-range ordering. We find that the [110] and [001] In-In pair correlations are repulsive and nearly isotropic in bulk but are highly anisotropic near the (001) surface. The sign of the [110] In-In interaction energies vs the distance from the surface is oscillatory. These findings explain the recent puzzling cross-sectional X-STM results. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Zunger, Alex/A-6733-2013; Krausnick, Jennifer/D-6291-2013; Zhang, Shengbai/D-4885-2013; Cho, Jun-Hyung/R-7256-2016 OI Zhang, Shengbai/0000-0003-0833-5860; Cho, Jun-Hyung/0000-0002-1785-1835 NR 24 TC 26 Z9 27 U1 1 U2 8 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 APR 17 PY 2000 VL 84 IS 16 BP 3654 EP 3657 DI 10.1103/PhysRevLett.84.3654 PG 4 WC Physics, Multidisciplinary SC Physics GA 304VH UT WOS:000086504500038 ER PT J AU Kwok, WK Olsson, RJ Karapetrov, G Paulius, LM Moulton, WG Hofman, DJ Crabtree, GW AF Kwok, WK Olsson, RJ Karapetrov, G Paulius, LM Moulton, WG Hofman, DJ Crabtree, GW TI Critical points in heavy ion irradiated untwinned YBa2Cu3O7-delta crystals SO PHYSICAL REVIEW LETTERS LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTORS; LATTICE-MELTING TRANSITION; PHASE-DIAGRAM; BOSON LOCALIZATION; COLUMNAR DEFECTS; VORTEX; DISORDER; VORTICES; LINE AB The critical points in untwinned YBa2Cu3O7-delta crystals with dilute columnar defects an investigated. We find a convergence of a first order vortex melting line with an irreversibility line associated with the onset of the Bose glass critical regime at the lower critical point. In addition, we find that columnar defects raise the upper critical point, implying that vortex line meandering is a basic feature controlling its position. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Sci & Technol Ctr Supercond, Argonne, IL 60439 USA. Western Michigan Univ, Dept Phys, Kalamazoo, MI 49008 USA. Florida State Univ, Dept Phys, Natl Lab High Energy Phys, Tallahassee, FL 32306 USA. Univ Illinois, Dept Phys, Chicago, IL 60607 USA. RP Kwok, WK (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 29 TC 51 Z9 51 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 APR 17 PY 2000 VL 84 IS 16 BP 3706 EP 3709 DI 10.1103/PhysRevLett.84.3706 PG 4 WC Physics, Multidisciplinary SC Physics GA 304VH UT WOS:000086504500051 ER PT J AU Luo, ZP Tang, YL Miller, DJ AF Luo, ZP Tang, YL Miller, DJ TI Comment on "Quasicrystal-crystal transformation in Zn-Mg-rare-earth alloys" SO PHYSICAL REVIEW LETTERS LA English DT Article ID ICOSAHEDRAL PHASE; QUASI-CRYSTALS; SYSTEM C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Luo, ZP (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Luo, Zhiping/C-4435-2014 OI Luo, Zhiping/0000-0002-8264-6424 NR 10 TC 5 Z9 5 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 APR 17 PY 2000 VL 84 IS 16 BP 3730 EP 3730 DI 10.1103/PhysRevLett.84.3730 PG 1 WC Physics, Multidisciplinary SC Physics GA 304VH UT WOS:000086504500057 ER PT J AU Dellago, C Hoover, WG AF Dellago, C Hoover, WG TI Are local Lyapunov exponents continuous in phase space? SO PHYSICS LETTERS A LA English DT Article DE Lyapunov exponents; ergodic systems AB Local expansion rates of small displacements in phase space are calculated for two simple ergodic model systems, one with hard elastic collisions, the other with smooth forces. We find that the local expansion rates are singular functions of the phase space coordinates. The singularities are caused by bifurcations occuring in the histories belonging to the phase-space points. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Rochester, Dept Chem, Rochester, NY 14627 USA. Univ Calif Lawrence Livermore Natl Lab, Methods Dev Grp, Livermore, CA 94551 USA. Univ Calif Davis, Dept Appl Sci, Livermore, CA 94551 USA. RP Dellago, C (reprint author), Univ Rochester, Dept Chem, Rochester, NY 14627 USA. RI Dellago, Christoph/E-1625-2011 NR 6 TC 9 Z9 9 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 APR 17 PY 2000 VL 268 IS 4-6 BP 330 EP 334 DI 10.1016/S0375-9601(00)00218-8 PG 5 WC Physics, Multidisciplinary SC Physics GA 307CJ UT WOS:000086635600020 ER PT J AU Cheng, BL Glimm, J Sharp, DH AF Cheng, BL Glimm, J Sharp, DH TI Density dependence of Rayleigh-Taylor and Richtmyer-Meshkov mixing fronts SO PHYSICS LETTERS A LA English DT Article ID 2-PHASE FLOW MODEL; INSTABILITY; EVOLUTION AB We propose a pair of ordinary differential equations to describe the motion of the two edges of a Rayleigh-Taylor (RT) or Richtmyer-Meshkov (RM) mixing zone. These model equations give a simple physics - based description of the RT and RM mixing rates. The equations are in agreement with all available experiments, including the recent LEM RT and RM experiments for spikes as well as bubbles. In particular, the model equations predict that the scaling constants alpha(s) --> 0.5 and theta --> 1 as the Atwood number A --> 1. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Appl Phys, Los Alamos, NM 87545 USA. SUNY Stony Brook, Dept Appl Math & Stat, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Ctr Data Intens Comp, Upton, NY 11793 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Cheng, BL (reprint author), Univ Calif Los Alamos Natl Lab, Div Appl Phys, Los Alamos, NM 87545 USA. NR 27 TC 46 Z9 47 U1 0 U2 6 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 APR 17 PY 2000 VL 268 IS 4-6 BP 366 EP 374 DI 10.1016/S0375-9601(00)00204-8 PG 9 WC Physics, Multidisciplinary SC Physics GA 307CJ UT WOS:000086635600025 ER PT J AU Gilmer, GH Huang, HC de la Rubia, TD Dalla Torre, J Baumann, F AF Gilmer, GH Huang, HC de la Rubia, TD Dalla Torre, J Baumann, F TI Lattice Monte Carlo models of thin film deposition SO THIN SOLID FILMS LA English DT Article DE lattice Monte Carlo models; thin film deposition; crystal growth ID VAPOR-DEPOSITION; GRAIN-GROWTH; CRYSTAL-GROWTH; SIMULATION; DIFFUSION AB Monte Carlo models of crystal growth have contributed to the theoretical understanding of thin film deposition, and are now becoming available as tools to assist in device fabrication. Because they combine efficient computation and atomic-level detail, these models can be applied to a large number of crystallization phenomena. They have played a central role in the understanding of the surface roughening transition and its effect on crystal growth kinetics. Ln addition, columnar growth, vacancy and impurity trapping, and other growth phenomena that are closely related to atomic-level structure have been investigated by these simulations. in this chapter we review some of these applications and discuss MC modeling of sputter deposition based on materials parameters derived from first principles and molecular dynamics methods. We discuss models of deposition which include the atomic scale, but can also simulate film structure evolution on time scales of the order of hours. By the use of advanced computers and algorithms, we can now simulate systems large enough to exhibit clustered, columnar, and polycrystalline film structures. The event distribution is determined from molecular dynamics simulations, which can give diffusion rates, defect production, sputtering yields, and other information needed to match real materials. We discuss simulations of deposition into small vias and trenches, and their extension to the length scale of real devices through scaling relations. (C) 2000 Published by Elsevier Science S.A. All rights reserved. C1 Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Gilmer, GH (reprint author), Bell Labs, Lucent Technol, 600 Mt Ave, Murray Hill, NJ 07974 USA. RI Huang, Hanchen/A-9323-2008 NR 31 TC 98 Z9 109 U1 4 U2 35 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 APR 17 PY 2000 VL 365 IS 2 BP 189 EP 200 DI 10.1016/S0040-6090(99)01057-3 PG 12 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 312JL UT WOS:000086940100004 ER PT J AU Theiss, SK Caturla, MJ Johnson, MD Zhu, J Lenosky, T Sadigh, B de la Rubia, TD AF Theiss, SK Caturla, MJ Johnson, MD Zhu, J Lenosky, T Sadigh, B de la Rubia, TD TI Atomic scale models of ion implantation and dopant diffusion in silicon SO THIN SOLID FILMS LA English DT Article DE ion implantation; dopant diffusion; silicon; atomic scale model; trapping ID OXIDATION-ENHANCED DIFFUSION; INITIO PSEUDOPOTENTIAL CALCULATIONS; SELF-INTERSTITIAL DIFFUSIVITIES; B-DOPING-SUPERLATTICES; POINT-DEFECT; COMPUTER-SIMULATION; ANNEALING KINETICS; GOLD DIFFUSION; SI; CARBON AB We review our recent work on an atomistic approach to the development of predictive process simulation tools. First-principles methods, molecular dynamics simulations, and experimental results are used to construct a database of defect and dopant energetics in Si. This is used as input for kinetic Monte Carlo simulations. C and B trapping of the Si self-interstitial is shown to help explain the enormous disparity in its measured diffusivity. Excellent agreement is found between experiments and simulations of transient enhanced diffusion following 20-80 keV B implants into Si, and with those of 50 keV Si implants into complex B-doped structures. Our simulations predict novel behavior of the time evolution of the electrically active B fraction during annealing. (C) 2000 Published by Elsevier Science S.A. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Theiss, SK (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RI Caturla, Maria /D-6241-2012 OI Caturla, Maria /0000-0002-4809-6553 NR 73 TC 32 Z9 32 U1 1 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 APR 17 PY 2000 VL 365 IS 2 BP 219 EP 230 DI 10.1016/S0040-6090(00)00757-4 PG 12 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 312JL UT WOS:000086940100007 ER PT J AU Coltrin, ME Ho, P Moffat, HK Buss, RJ AF Coltrin, ME Ho, P Moffat, HK Buss, RJ TI Chemical kinetics in chemical vapor deposition: growth of silicon dioxide from tetraethoxysilane (TEOS) SO THIN SOLID FILMS LA English DT Article DE chemical vapor deposition; tetraethylsiloxane; microelectronics ID SURFACE-REACTION KINETICS; LOW-PRESSURE CVD; CL-H SYSTEM; GAS-PHASE; TETRAMETHYL ORTHOSILICATE; DIAMOND GROWTH; THERMOCHEMISTRY; MOLECULES; SI; DECOMPOSITION AB Chemical reactions in the gas-phase and on surfaces are important in the chemical vapor deposition (CVD) of materials for microelectronic applications. General approaches for modeling the homogeneous and heterogeneous kinetics in CVD are discussed. A software framework for implementing the theory utilizing the CHEMKIN suite of codes is presented. Specific examples are drawn from the CVD of SiO(2) using tetraethoxysilane (TEOS). Experimental molecular beam reactive-sticking coefficient studies were employed to extract surface-reaction rate constants. Numerical simulations were used to analyze the molecular-beam experiments and low-pressure tube furnace data, illustrating the general modeling approach. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Coltrin, ME (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 68 TC 33 Z9 33 U1 2 U2 23 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 APR 17 PY 2000 VL 365 IS 2 BP 251 EP 263 DI 10.1016/S0040-6090(99)01059-7 PG 13 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 312JL UT WOS:000086940100010 ER PT J AU Meeks, E Ho, P AF Meeks, E Ho, P TI Modeling plasma chemistry for microelectronics manufacturing SO THIN SOLID FILMS LA English DT Review DE plasma chemistry; microelectronics; processor; numerical model ID INDUCTIVELY-COUPLED PLASMA; ELECTRON-IMPACT IONIZATION; SIMULATION MONTE-CARLO; 2-DIMENSIONAL FLUID MODEL; SPATIALLY-AVERAGED MODEL; CROSS-SECTIONS; RECOMMENDED DATA; DEPOSITING FILM; SILICON DIOXIDE; ETCH PROCESSES AB A methodology is presented for developing and testing plasma chemistry mechanisms needed for numerical models of microelectronics processing technologies. This includes a description of the types of data required for building a kinetic model, common sources for obtaining fundamental and kinetic data, suggestions for estimating kinetic parameters when data are not available, and approaches to validation and tuning of the model using diagnostic and sensor data. The approach focuses on the use of the CHEMIN Collection software for describing the gas-phase and surface reaction kinetics in high-density plasma simulations. (C) 2000 Elsevier Science S.A. All rights reserved. C1 React Design Inc, San Diego, CA 92121 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Meeks, E (reprint author), 304 Daisyfield Dr, Livermore, CA 94550 USA. NR 101 TC 25 Z9 25 U1 1 U2 11 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD APR 17 PY 2000 VL 365 IS 2 BP 334 EP 347 DI 10.1016/S0040-6090(99)01048-2 PG 14 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 312JL UT WOS:000086940100016 ER PT J AU Daum, PH Kleinman, LI Imre, D Nunnermacker, LJ Lee, YN Springston, SR Newman, L Weinstein-Lloyd, J Valente, RJ Imhoff, RE Tanner, RL Meagher, JF AF Daum, PH Kleinman, LI Imre, D Nunnermacker, LJ Lee, YN Springston, SR Newman, L Weinstein-Lloyd, J Valente, RJ Imhoff, RE Tanner, RL Meagher, JF TI Analysis of O-3 formation during a stagnation episode in central Tennessee in summer 1995 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SOUTHEASTERN UNITED-STATES; SOUTHERN OXIDANTS; OZONE PRODUCTION; REGIONAL OZONE; BIOGENIC HYDROCARBONS; NASHVILLE; TRANSPORT; CHEMISTRY; PEROXIDES; NITROGEN AB O-3 production in the Nashville urban plume during the O-3 episode that occurred on July 11-July 13 1995, is examined to characterize the factors that control the ozone production rate and efficiency, and to examine the relative importance of natural and anthropogenic sources of hydrocarbons to ozone production in the urban center and outlying areas. The analysis focuses on data collected during aircraft flights on July 11 when the Nashville area was sampled more or less continuously from about 1000 to 1800 LT. The instantaneous ozone production rate P(O-3) in the downtown area from late morning through midafternoon on July 11 ranged between 10 and greater than 30 pphv/h depending on location. After 1700 local time, production rates dropped to a few ppbv/h owing to the diminished solar intensity. Instantaneous production efficiencies with respect to NOx in the downtown area ranged between 2.5 and 8, linearly depending on the ratio of the hydrocarbon to NOx, OH reactivity. Integral O-3 production efficiencies corrected for NOz losses ranged between 1.5 and 4, The lowest efficiency was observed in the downtown area in the morning where NOx concentrations were high and hydrocarbon to NOx reactivity ratios were the lowest. Throughout the day, P(O-3) in the downtown area was limited by the availability of hydrocarbons. Anthropogenic hydrocarbons and CO contributed about 66% of the total hydrocarbon OR reactivity in the downtown area. In the mature urban plume downwind of Nashville, P(O-3) dropped to 6-9 ppbv/h at midafternoon and was controlled by the availability of NOx. Integral O-3 production efficiencies in the mature urban plume ranged between 3.5 and 4. When present in large quantities (1-3 ppbv), isoprene significantly increased both the rate and efficiency of ozone production as long as the photochemical system was not strongly NOx-limited. C1 Brookhaven Natl Lab, Dept Appl Sci, Environm Chem Div, Upton, NY 11973 USA. Tennessee Valley Author, Dept Atmospher Sci, Muscle Shoals, AL 35662 USA. SUNY Old Westbury, Dept Chem & Phys, Old Westbury, NY 11586 USA. RP Daum, PH (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Environm Chem Div, Upton, NY 11973 USA. EM phdaum@bnl.gov NR 17 TC 30 Z9 30 U1 0 U2 3 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 APR 16 PY 2000 VL 105 IS D7 BP 9107 EP 9119 DI 10.1029/1999JD900350 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 306FJ UT WOS:000086586400017 ER PT J AU Baumann, K Williams, EJ Angevine, WM Roberts, JM Norton, RB Frost, GJ Fehsenfeld, FC Springston, SR Bertman, SB Hartsell, B AF Baumann, K Williams, EJ Angevine, WM Roberts, JM Norton, RB Frost, GJ Fehsenfeld, FC Springston, SR Bertman, SB Hartsell, B TI Ozone production and transport near Nashville, Tennessee: Results from the 1994 study at New Hendersonville SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SOUTHEASTERN UNITED-STATES; OBSERVATORY PHOTOCHEMISTRY EXPERIMENT; BOUNDARY-LAYER; PHOTOSTATIONARY STATE; BIOGENIC HYDROCARBONS; REACTIVE NITROGEN; REGIONAL OZONE; NIWOT RIDGE; MODEL; NO2 AB During the summer of 1994 the photochemical production of ozone and the relation of this production to the photochemical precursors were studied at a suburban ground site near Nashville, Tennessee. The study, which was carried out as part of the Southern Oxidant Study (SOS), investigated the ozone produced by urban outflow during one period of high photochemical activity around July 1, 1994. Estimates of the instantaneous rate of in situ ozone production, P(O-3), are inferred from deviations of the photostationary state (PSS) for clear-sky conditions. The biggest contributor to the large errors in P(O-3) are the systematic errors in the derived, nor measured, j(NO2) levels. Ozone entrainment from aloft has been quantified by simple subtraction of calculated production and loss terms from the observed rate of ozone change. The uncertainty of this derived transport term was estimated to a factor of 2 at best and 2 orders of magnitude at worst. Entrainment provides a substantial contribution to the observed increase of [O-3] (similar to 20 ppbv h(-1)) in the mornings between 0700 and 1000 Central Standard Time (CST being 1 hour behind LT) when advection can be neglected. An average entrainment velocity of 1.5-2 cm s(-1) agreed within 30 to 50% with a result found from another, completely independent study. P(O-3) dominates the observed [O-3] increase from 1000 CST until early afternoon, when entrainment weakens and even turns into an effective ozone loss term due to cloud venting processes. The July 1 case clearly demonstrates that the morning ozone entrainment occurs on a more regional scale covering the entire study area, whereas the midday ozone exceedance was spatially more confined to the area covered by the advective outflow of the chemically processed Nashville urban plume. The data show that the entrained [O-3]-rich air aloft is the remnant of the previous day's local ozone buildup and subsequent nocturnal advective redistribution. C1 Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. Natl Ctr Atmospher Res, Adv Study Program, Boulder, CO 80307 USA. Brookhaven Natl Lab, Environm Chem Div, Upton, NY 11973 USA. Western Michigan Univ, Dept Chem, Kalamazoo, MI 49008 USA. Atmospher Res & Anal Inc, Plano, TX 75093 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Baumann, K (reprint author), Georgia Inst Technol, Sch Earth & Atmospher Sci, 221 Bobby Dodd Way,OCE 205, Atlanta, GA 30332 USA. EM kb@eas.gatech.edu; eric@al.noaa.gov; wayne@al.noaa.gov RI Roberts, James/A-1082-2009; Williams, Eric/F-1184-2010; Angevine, Wayne/H-9849-2013; Frost, Gregory/I-1958-2013; Fehsenfeld, Frederick/I-4876-2013 OI Roberts, James/0000-0002-8485-8172; Angevine, Wayne/0000-0002-8021-7116; NR 47 TC 22 Z9 22 U1 0 U2 0 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 APR 16 PY 2000 VL 105 IS D7 BP 9137 EP 9153 DI 10.1029/1999JD901017 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 306FJ UT WOS:000086586400019 ER PT J AU Daum, PH Kleinman, L Imre, DG Nunnermacker, LJ Lee, YN Springston, SR Newman, L Weinstein-Lloyd, J AF Daum, PH Kleinman, L Imre, DG Nunnermacker, LJ Lee, YN Springston, SR Newman, L Weinstein-Lloyd, J TI Analysis of the processing of Nashville urban emissions on July 3 and July 18, 1995 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID UNITED-STATES; OZONE; CHEMISTRY; MODEL; MECHANISM; NITROGEN AB This paper analyzes data obtained on July 3 and 18, 1995, during the summer 1995 Southern Oxidant Study (SOS) field campaign. In a previous paper [Nunnermacker et al., 1998] we analyzed measurements of key species that contribute to formation of O-3 in the Nashville urban plume and presented a semiquantitative picture of O-3 production in the plume from the point of emission to locations where no net O-3 was being formed. In this paper we use a box model constrained by observed concentrations of stable species to obtain a detailed mechanistic description of the instantaneous processing of urban emissions at various times in the chemical evolution of the urban plume. Instantaneous ozone production rates and efficiencies with respect to NOx and to primary radical production are examined. At high NOx concentrations in the fresh urban plume the O-3 production rate was found to be directly proportional to the hydrocarbon to NOx reactivity ratio. At lower NO, concentrations, corresponding to the mature urban plume and the background atmosphere, the O-3 production rate was found to be directly proportional to the NOx concentration and independent of the hydrocarbon reactivity. NOx was found to be most efficiently used for ozone production at low NOx concentrations. In contrast, the efficiency with which the system uses primary radicals was found to be very low at low NOx concentrations and to peak at a NO, concentration of approximately 4 ppbv. A sensitivity study of the instantaneous O-3 production rates to changes in NOx or hydrocarbon concentrations showed that the instantaneous O-3 production rate at the center of the urban plume, when half of the urban NOx emissions had been processed, is hydrocarbon sensitive. However, O-3 production becomes NOx sensitive as the plume matures. C1 Brookhaven Natl Lab, Dept Appl Sci, Environm Chem Div, Upton, NY 11973 USA. SUNY Old Westbury, Dept Chem & Phys, Old Westbury, NY 11586 USA. RP Daum, PH (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Environm Chem Div, Upton, NY 11973 USA. EM phdaum@bnl.gov NR 12 TC 22 Z9 23 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 APR 16 PY 2000 VL 105 IS D7 BP 9155 EP 9164 DI 10.1029/1999JD900997 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 306FJ UT WOS:000086586400020 ER PT J AU Nunnermacker, LJ Kleinman, LI Imre, D Daum, PH Lee, YN Lee, JH Springston, SR Newman, L Gillani, N AF Nunnermacker, LJ Kleinman, LI Imre, D Daum, PH Lee, YN Lee, JH Springston, SR Newman, L Gillani, N TI NOy lifetimes and O-3 production efficiencies in urban and power plant plumes: Analysis of field data SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CHEMICALLY REACTIVE PLUME; 1995 SOUTHERN OXIDANTS; EASTERN-UNITED-STATES; DRY DEPOSITION; TROPOSPHERIC OZONE; RURAL OZONE; NASHVILLE; TURBULENCE; EMISSIONS; AIRCRAFT AB In an effort to describe and characterize power plant plumes in the Nashville region, emissions from a small power plant (Gallatin) and a large power plant (Paradise) were examined using data obtained on the Department of Energy G-1 airborne sampling platform. Observations made on July 3, 7, 15, 17, and 18, 1995, were compiled, and a kinetic analysis of the chemical evolution of the power plant plumes was performed. Analysis of the power plant plume data revealed a very active photochemistry, as had been determined previously for the urban plume. Ozone production efficiencies (OPE), defined as the number of molecules of O-3 formed per NOx molecule consumed, were found to be 3 for Gallatin and 2 for Paradise. Lifetimes for NOx (2.8 and 4.2 hours) and NOy (7.0 and 7.7 hours) were determined for Gallatin and Paradise, respectively. These NOx and NOy lifetimes imply rapid loss of NOz (NOz is assumed to be primarily HNO3). Lifetimes for NOz are calculated to be 3 and 2.5 hours for Gallatin and Paradise, respectively. A sensitivity analysis indicates that the Gallatin NOz lifetime could be as long as 5 hours, bringing it into agreement with the value determined for the Nashville urban plume. It is unlikely that the Paradise NOz lifetime is as long as 4 hours. If NOz loss is attributed to dry deposition, a 3 hour lifetime implies a deposition velocity greater than 10 cm s(-1), which is much faster than expected based on accepted theory. Possible reasons for this discrepancy are discussed. C1 Brookhaven Natl Lab, Dept Appl Sci, Environm Chem Div, Upton, NY 11973 USA. Univ Alabama, NASA, UAH Global Hydrol & Climate Ctr, Earth Syst Sci Lab, Huntsville, AL 35806 USA. RP Nunnermacker, LJ (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Environm Chem Div, Upton, NY 11973 USA. EM lindan@bnl.gov NR 36 TC 31 Z9 33 U1 2 U2 13 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 16 PY 2000 VL 105 IS D7 BP 9165 EP 9176 DI 10.1029/1999JD900753 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 306FJ UT WOS:000086586400021 ER PT J AU Doran, JC Zhong, S AF Doran, JC Zhong, S TI A study of the effects of sub-grid-scale land use differences on atmospheric stability in prestorm environments SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GREAT-PLAINS CLOUD; SURFACE; PRECIPITATION; RADIATION; CONVECTION; MOISTURE; IMPACT; MODEL AB The effects of sub-grid-scale land use differences in modifying the stability of prestorm environments has been studied using data from the Department of Energy Cloud and Radiation Testbed (CART) in Kansas and Oklahoma and a mesoscale model. To quantify the atmospheric instability, three indices were used: the lifted index, the modified K index, and convective available potential energy. The spatial variations of these indices were calculated from simulations using spatially varying and spatially uniform surface fluxes as lower boundary conditions. The CART is approximately 10(5) km(2) in area and is characterized by large areas of contrasting vegetation cover and surface sensible and latent heat fluxes. The spatially varying fluxes were calculated with the SiB2 model using data from the CART. Six days, during which isolated thunderstorms developed, were chosen for the study. The results suggest that sub-grid-scale variations in land use differences do not modify the spatial distribution of the stability indices in the southern Great Plains to any significant degree. Predictions of areas of preferred development of deep convection, based on changes in the indices, are not improved by accounting for sub-grid-scale variations in land use. The indices were found to be potentially useful but imperfect indicators of the occurrence of deep convective precipitation at scales smaller than that of the CART. At the model resolution used (grid spacing of 2.08 km) a close correlation was not found between regions of precipitation and regions with enhanced simulated vertical updrafts related to land-use differences, but a detailed study of local triggering has not been carried out. C1 Pacific NW Lab, Richland, WA 99352 USA. RP Doran, JC (reprint author), Pacific NW Lab, POB 999,MSIN K9-30, Richland, WA 99352 USA. EM christopher.doran@pnl.gov; shiyuan.zhong@pnl.gov NR 20 TC 13 Z9 13 U1 0 U2 2 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 APR 16 PY 2000 VL 105 IS D7 BP 9381 EP 9392 DI 10.1029/1999JD901121 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 306FJ UT WOS:000086586400037 ER PT J AU Engelen, RJ Fowler, LD Gleckler, PJ Wehner, MF AF Engelen, RJ Fowler, LD Gleckler, PJ Wehner, MF TI Sampling strategies for the comparison of climate model calculated and satellite observed brightness temperatures SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GENERAL-CIRCULATION MODEL; INTERANNUAL VARIABILITY; RADIATION BUDGET; TROPICS; DATASET; SURFACE; BIASES; CLOUDS AB Brightness temperatures derived from polar-orbiting satellites are valuable for the evaluation of global climate models. However, the effect of orbital constraints must be taken into account to ensure valid comparisons. As part of the Atmospheric Model Intercomparison Project II climate model comparisons, this study seeks to evaluate the monthly mean simulated brightness temperature differences of possible model output sampling strategies with respect to the exact satellite sampling and whether they can be practically implemented to provide meaningful comparisons with these satellite observations. We compare various sampling strategies with a proxy satellite data set constructed from model output and actual TIROS operational vertical sounder orbital trajectories, rather than with the observations themselves. To a large extent, this enables isolation of the sampling error from errors caused by deficiencies in the modeled climate processes. Our results suggest that the traditional method of calculating brightness temperatures from monthly mean temperature and moisture profiles yields biases from both nonlinear effects and the removal of the diurnal cycle that may be unacceptable in many applications. However, we also find that a brightness temperature calculation every hour of the simulation provides substantially lower sampling biases provided that there are two or more properly aligned satellites. This is encouraging because it means that for many applications modelers need not accurately mimic actual satellite trajectories in the sampling of their simulations. If only one satellite is available for comparison with simulations, more sophisticated sampling seems necessary. For such circumstances, we introduce a simple procedure that serves as a useful approximation to the rather complex procedure required to sample a model exactly as a polar-orbiting satellite does the Earth. With all sampling methods, removal of biases associated with cloud cover is problematic and deserves further study. C1 Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. Lawrence Livermore Natl Lab, Program Climate Model Diag & Intercomparison, Livermore, CA 94550 USA. RP Engelen, RJ (reprint author), Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. EM richard@atmos.colostate.edu; laura@atmos.colostate.edu; gleckler@pcmdi.llnl.gov; mwehner@pcmdi.llnl.gov RI Gleckler, Peter/H-4762-2012 OI Gleckler, Peter/0000-0003-2816-6224 NR 29 TC 10 Z9 10 U1 0 U2 2 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 APR 16 PY 2000 VL 105 IS D7 BP 9393 EP 9406 DI 10.1029/1999JD901182 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 306FJ UT WOS:000086586400038 ER PT J AU Wallenborg, SR Bailey, CG AF Wallenborg, SR Bailey, CG TI Separation and detection of explosives on a microchip using micellar electrokinetic chromatography and indirect laser-induced fluorescence SO ANALYTICAL CHEMISTRY LA English DT Article ID OPEN-CHANNEL ELECTROCHROMATOGRAPHY; CAPILLARY ELECTROPHORESIS; ELECTROCHEMICAL DETECTION; NITROAROMATIC EXPLOSIVES; LIQUID-CHROMATOGRAPHY; SAMPLE INJECTION; ANALYSIS SYSTEMS; GLASS CHIPS; PERFORMANCE; NITRAMINE AB A new approach for sensitive detection on a microfabricated chip is presented. Indirect laser-induced-fluorescence (IDLIF) was used to detect explosive compounds after separation by micellar electrokinetic chromatography (MEKC), The detection setup was used in an epifluorescence configuration with excitation provided by a near-IR diode laser operating at 750 nm, To achieve indirect detection, a low concentration of a dye (5 mu M Cy7) was added to the running buffer as a visualizing agent. Using this methodology, a sample containing 14 explosives (EPA 8330 mixture) was examined. Concentrations of 1 ppm of trinitrobenzene (TNB), trinitrotoluene (TNT), dinitrobenzene (DNB), tetryl, and 2,4-dinitrotoluene (2,4-DNT) could be detected with S/N ratios between 3 and 10, Analyses showing 10 peaks, with plate numbers on the order of 60 000, were completed within 60 s using a 65 mm long separation channel. The three isomers of nitrotoluene (2-, 3-, and 4-nitrotoluene) were not resolved. Additionally, the two nitramines (HMX and RDX) could only be detected at much higher concentrations, likely due to the low fluorescence quenching efficiencies of these compounds. The analysis method was also used to separate and detect nitroaromatic compounds in extracts from spiked soil samples. The presence of 1 ppm (1 mu g of analyte/1 g of soil) of TNB, DNB, TNT, tetryl, 2,4-DNT, 2,6-DNT, 2-NH2-4,6-DNT, and 4-NH2-2,6-DNT could readily be detected. In the interest of increasing the sensitivity of the analysis, various on-chip injection schemes were evaluated. It was found that a 250 mu m double-T injector gave a 35% increase in peak signal compared to a straight-cross injector, which is less than expected based on injected volume. C1 Sandia Natl Labs, Livermore, CA 94551 USA. RP Bailey, CG (reprint author), Sandia Natl Labs, POB 969-MS9671, Livermore, CA 94551 USA. NR 44 TC 116 Z9 126 U1 1 U2 29 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 APR 15 PY 2000 VL 72 IS 8 BP 1872 EP 1878 DI 10.1021/ac991382y PG 7 WC Chemistry, Analytical SC Chemistry GA 304RD UT WOS:000086497200023 ER PT J AU Masselon, C Anderson, GA Harkewicz, R Bruce, JE Pasa-Tolic, L Smith, RD AF Masselon, C Anderson, GA Harkewicz, R Bruce, JE Pasa-Tolic, L Smith, RD TI Accurate mass multiplexed tandem mass spectrometry for high-throughput polypeptide identification from mixtures SO ANALYTICAL CHEMISTRY LA English DT Article ID PROTEINS; DISSOCIATION; PEPTIDES; IONS; ELECTROPHORESIS; EXCITATION; PROTEOME; SPECTRA AB We report a new tandem mass spectrometric approach for the improved identification of polypeptides from mixtures (e.g., using genomic databases). The approach involves the dissociation of several species simultaneously in a single experiment and provides both increased speed and sensitivity, The data analysis makes use of the known fragmentation pathways for polypeptides and highly accurate mass measurements for both the set of parent polypeptides and their fragments. The accurate mass information makes it possible to attribute most fragments to a specific parent species. We provide an initial demonstration of this multiplexed tandem MS approach using an FTICR mass spectrometer with a mixture of seven polypeptides dissociated using infrared irradiation from a CO2 laser. The peptides were added to, and then successfully identified from, the largest genomic database yet available (C. elegans), which is equivalent in complexity to that for a specific differentiated mammalian cell type. Additionally, since only a few enzymatic fragments are necessary to unambiguously identify a protein from an appropriate database, it is anticipated that the multiplexed MS/MS method will allow the more rapid identification of complex protein mixtures with on-line separation of their enzymatically produced polypeptides. C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Pacific NW Lab, Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. RI Masselon, Christophe/A-2340-2010; Smith, Richard/J-3664-2012 OI Smith, Richard/0000-0002-2381-2349 NR 28 TC 86 Z9 88 U1 0 U2 4 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 APR 15 PY 2000 VL 72 IS 8 BP 1918 EP 1924 DI 10.1021/ac991133+ PG 7 WC Chemistry, Analytical SC Chemistry GA 304RD UT WOS:000086497200029 PM 10784162 ER PT J AU Nordahl, TE Carter, C Kraft, L Baldo, J Salamat, S Salo, R Kusubov, N AF Nordahl, TE Carter, C Kraft, L Baldo, J Salamat, S Salo, R Kusubov, N TI Right anterior cingulate metabolic abnormality in chronic paranoid schizophrenia SO BIOLOGICAL PSYCHIATRY LA English DT Meeting Abstract C1 Univ Calif Davis, Napa State Res Ctr, Napa, CA 94557 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0006-3223 J9 BIOL PSYCHIAT JI Biol. Psychiatry PD APR 15 PY 2000 VL 47 IS 8 SU S MA 151 BP 45S EP 46S DI 10.1016/S0006-3223(00)00413-3 PG 2 WC Neurosciences; Psychiatry SC Neurosciences & Neurology; Psychiatry GA 304ZW UT WOS:000086515200149 ER PT J AU Maletinska, L Blakely, EA Bjornstad, KA Deen, DF Knoff, LJ Forte, TM AF Maletinska, L Blakely, EA Bjornstad, KA Deen, DF Knoff, LJ Forte, TM TI Human glioblastoma cell lines: Levels of low-density lipoprotein receptor and low-density lipoprotein receptor-related protein SO CANCER RESEARCH LA English DT Article ID HUMAN GLIOMA-CELLS; HUMAN BRAIN; ALPHA(2)-MACROGLOBULIN RECEPTOR; SUBCELLULAR-LOCALIZATION; MEDIATED ENDOCYTOSIS; CEREBROSPINAL-FLUID; CANCER-CELLS; GLIAL-CELLS; PATHWAY; EXPRESSION AB The status of the low-density lipoprotein (LDL) receptor and LDL receptor-related protein (LRP) in seven human glioma cell lines was evaluated to extend our knowledge of human glioblastoma multiforme tumor metabolism for future drug design. Cell lines SF-767, SF-763, A-172, U-87 MG, U-251 MG, U343 MG, and SF-539 were used. Binding of I-125-labeled LDL to these cells at 4 degrees C was carried out to determine the number of LDL receptors on cells and the affinity of LDL for these receptors, The content of LRP was measured by immunoblotting. The presence of specific saturable LDL receptors was proven in six of the cell lines investigated. SF-767 cells revealed high-affinity LDL binding (equilibrium dissociation constant, K-d = 7 nM) and maximum binding capacity approximating 300,000 receptors/cell, Most of the remaining cell lines had relatively lower affinity (K-d = 38-62 nM) but also had very high numbers of receptors (128,000-950,000/cell). All cell lines exhibited LRP, but the expression was variable. The cell lines SF-539, U-87 MG, and U-343 MG were particularly rich in this protein. The data suggest that glioblastoma cells have high numbers of LDL receptors; however, there is considerable variation in binding affinity. Overall, this finding suggests that LDL receptors on glioblastoma cells could potentially be useful for targeting antitumor agents. LRP, a multifunctional receptor expressed on glioblastoma cells, also has the possibility for serving as a therapeutic target. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Univ Calif San Francisco, Brain Tumor Res Ctr, San Francisco, CA 94143 USA. RP Forte, TM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, 1 Cyclotron Rd,MS 1-315A, Berkeley, CA 94720 USA. FU NCI NIH HHS [CA-13525]; NHLBI NIH HHS [HL-18574] NR 36 TC 85 Z9 88 U1 1 U2 11 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 APR 15 PY 2000 VL 60 IS 8 BP 2300 EP 2303 PG 4 WC Oncology SC Oncology GA 308EA UT WOS:000086696500039 PM 10786698 ER PT J AU Kemna, A Binley, A Ramirez, A Daily, W AF Kemna, A Binley, A Ramirez, A Daily, W TI Complex resistivity tomography for environmental applications SO CHEMICAL ENGINEERING JOURNAL LA English DT Article; Proceedings Paper CT 1st World Congress on Industrial Process Tomography CY APR 14-17, 1999 CL BUXTON, ENGLAND DE complex resistivity; inversion; relaxation ID ELECTRICAL-PROPERTIES; POLARIZATION AB Complex resistivity may provide valuable information about the structural and hydraulic nature of porous media and fluids contained within such media. The environmental value of such a property is obvious. To date most environmental applications of complex resistivity have focussed on relatively crude data analysis methods and restrictive electrode configurations. New tomographic methods are becoming available that will allow complex resistivity to be employed with arbitrary electrode arrangements. Laboratory trials of our extensions of electrical resistivity tomography to a complex form are reported. The inversion procedure is presented and demonstrated for a range of targets, with resistive and reactive characteristics. The approach is shown to provide useful magnitude and phase images, giving spectral information about the region of interest. Cole-Cole analysis of the inversion results reveals specific material relaxation characteristics. The usefulness of imaging complex resistivity is evident when compared with more conventional resistivity tomography, in particular when examined over a range of input frequencies. (C)2000 Elsevier Science S.A. All rights reserved. C1 DMT GeoTec Div, D-45307 Essen, Germany. Univ Lancaster, Lancaster LA1 4YQ, England. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Kemna, A (reprint author), DMT GeoTec Div, D-45307 Essen, Germany. RI Binley, Andrew/C-2487-2013 OI Binley, Andrew/0000-0002-0938-9070 NR 13 TC 74 Z9 78 U1 0 U2 10 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 1385-8947 J9 CHEM ENG J JI Chem. Eng. J. PD APR 15 PY 2000 VL 77 IS 1-2 BP 11 EP 18 DI 10.1016/S1385-8947(99)00135-7 PG 8 WC Engineering, Environmental; Engineering, Chemical SC Engineering GA 294PJ UT WOS:000085919400004 ER PT J AU Nasser, A Sposito, G Cheney, MA AF Nasser, A Sposito, G Cheney, MA TI Mechanochemical degradation of 2,4-D adsorbed on synthetic birnessite SO COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS LA English DT Article DE mechanochemical reaction; abiotic degradation; 2,4-dichlorophenoxyacetic acid; birnessite ID AL2O3 POWDERS; TRANSFORMATION; MANGANESE; KINETICS; SOILS; ACID AB Mechanochemical degradation of 2,4-D (2,4-dichlorophenoxyacetic acid) adsorbed on synthetic birnessite (delta-MnO2 was investigated using heat conduction calorimetry. The overall transformation kinetics of 2,4-D on birnessite after light grinding were approximately first-order, with an apparent activation energy of approximately 37 kJ mol(-1) for the range of temperatures 10-50 degrees C. The two decomposition products detected under mechanochemical degradation and incubation were 2,4-dichlorophenol and CO2, but no consumption of gaseous oxygen was detected. A positive correlation was found between Mn(II) produced and CO2 evolved, suggesting that the decomposition of 2,4-dichlorophenol involves the oxide substrate as a source of oxygen and yields Mn(II). (C) 2000 Elsevier Science B.V. All rights reserved. C1 Rutgers State Univ, Cook Coll, Dept Environm Sci, New Brunswick, NJ 08903 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Rutgers State Univ, Cook Coll, Dept Environm Sci, New Brunswick, NJ 08903 USA. EM cheney@aesop.rutgers.edu NR 19 TC 21 Z9 21 U1 1 U2 11 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-7757 EI 1873-4359 J9 COLLOID SURFACE A JI Colloid Surf. A-Physicochem. Eng. Asp. PD APR 15 PY 2000 VL 163 IS 2-3 BP 117 EP 123 DI 10.1016/S0927-7757(99)00297-6 PG 7 WC Chemistry, Physical SC Chemistry GA 285DK UT WOS:000085374200001 ER PT J AU Zhang, DX Zhang, RY Chen, SY Soll, VE AF Zhang, DX Zhang, RY Chen, SY Soll, VE TI Pore scale study of flow in porous media: Scale dependency, REV, and statistical REV SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID X-RAY MICROTOMOGRAPHY; TRANSPORT; SANDSTONE AB Flow in porous media is studied at the pore-scale with lattice Boltzmann simulations on pore geometries reconstructed from computed microtomographic images. Pore scale results are analyzed to give quantities such as permeability, porosity and specific surface area at various scales and at various locations. With this, some fundamental issues such as scale dependency and medium variability can be assessed quantitatively. More specifically, the existence and size of the well known concept, representative elementary volume (REV), can be quantified. It is found that the size of an REV varies spatially and depends on the quantity being represented. For heterogeneous media, a better measure may be the so called "statistical REV", which has weaker requirements than does the deterministic REV. C1 Univ Calif Los Alamos Natl Lab, Geoanal Grp, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. RP Zhang, DX (reprint author), Univ Calif Los Alamos Natl Lab, Geoanal Grp, MS C306, Los Alamos, NM 87545 USA. RI Zhang, Dongxiao/D-5289-2009; Chen, Shiyi/A-3234-2010 OI Zhang, Dongxiao/0000-0001-6930-5994; NR 15 TC 105 Z9 106 U1 5 U2 35 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 APR 15 PY 2000 VL 27 IS 8 BP 1195 EP 1198 DI 10.1029/1999GL011101 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 305HW UT WOS:000086534700029 ER PT J AU Rothenberg, JE AF Rothenberg, JE TI Polarization beam smoothing for inertial confinement fusion SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID GLASS LASER SYSTEM; SUPPRESSION; UNIFORMITY; PLASMA; ILLUMINATION; INSTABILITY; INCOHERENCE; DISPERSION; LIGHT AB For both direct and indirect drive approaches to inertial confinement fusion (ICF) it is imperative to obtain the best possible drive beam uniformity. The approach chosen for the National Ignition Facility uses a random-phase plate to generate a speckle pattern with a precisely controlled envelope on target. A number of temporal smoothing techniques can then be employed to utilize bandwidth to rapidly change the speckle pattern, and thus average out the small-scale speckle structure. One technique which generally can supplement other smoothing methods is polarization smoothing (PS): the illumination of the target with two distinct and orthogonally polarized speckle patterns. Since these two polarizations do not interfere, the intensity patterns add incoherently, and the rms nonuniformity can be reduced by a factor of root 2. A number of PS schemes are described and compared on the basis of the aggregate rms and the spatial spectrum of the focused illumination distribution. The root 2 rms nonuniformity reduction of PS is present on an instantaneous basis and is, therefore, of particular interest for the suppression of laser plasma instabilities, which have a very rapid response time. When combining PS and temporal methods, such as smoothing by spectral dispersion (SSD), PS can reduce the rms of the temporally smoothed illumination by an additional factor of root 2. However, it has generally been thought that in order to achieve this reduction of root 2, the increased divergence of the beam from PS must exceed the divergence of SSD. It is also shown here that, over the time scales of interest to direct or indirect drive ICF, under some conditions PS can reduce the smoothed illumination rms by nearly root 2 even when the PS divergence is much smaller than that of SSD. (C) 2000 American Institute of Physics. [S0021-8979(00)00808-2]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Rothenberg, JE (reprint author), Univ Calif Lawrence Livermore Natl Lab, L-482,POB 808, Livermore, CA 94551 USA. NR 27 TC 32 Z9 34 U1 1 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 2000 VL 87 IS 8 BP 3654 EP 3662 DI 10.1063/1.372395 PG 9 WC Physics, Applied SC Physics GA 298YU UT WOS:000086169500006 ER PT J AU Choi, IH Eom, SH Yu, PY AF Choi, IH Eom, SH Yu, PY TI The optical and vibrational properties of the quaternary chalcopyrite semiconductor alloy AgxCu1-xGaS2 SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ANOMALOUS TEMPERATURE-DEPENDENCE; RAMAN-SCATTERING; BAND-GAP; LATTICE-DYNAMICS; ENERGY-GAP; AGGAS2; CUGAS2; CRYSTALS; COEFFICIENTS; MODES AB The absorption, emission and Raman spectra of the quaternary chalcopyrite alloys AgxCu1-xGaS2 have been measured as a function of the Ag concentration. We find strong and highly nonlinear dependence on the alloy concentration in the optical band gap (a large bowing parameter). On the other hand, most of the Raman peaks exhibit either small energy shifts or large broadening with alloying. We conclude that the effect of substitution of the Ag cations by Cu in AgGaS2 on its band structure cannot be predicted by the simple virtual crystal potential approximation as a result of the large difference in electronegativity and bond length between Ag and Cu. (C) 2000 American Institute of Physics. [S0021-8979(00)00308-X]. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Chung Ang Univ, Dept Phys, Seoul 156756, South Korea. RP Yu, PY (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NR 31 TC 15 Z9 15 U1 0 U2 9 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 2000 VL 87 IS 8 BP 3815 EP 3822 DI 10.1063/1.372419 PG 8 WC Physics, Applied SC Physics GA 298YU UT WOS:000086169500031 ER PT J AU Berghout, HL Crim, FF Zyrianov, M Reisler, H AF Berghout, HL Crim, FF Zyrianov, M Reisler, H TI The electronic origin and vibrational levels of the first excited singlet state of isocyanic acid (HNCO) SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID POTENTIAL-ENERGY SURFACES; PURE ROTATIONAL SPECTRA; COUPLED-CLUSTER METHOD; INFRARED-SPECTRUM; PHOTODISSOCIATION; SPECTROSCOPY; TRANSITION; EQUATION; CHANNELS; MODEL AB The combination of vibrationally mediated photofragment yield spectroscopy, which excites molecules prepared in single vibrational states, and multiphoton fluorescence spectroscopy, which excites molecules cooled in a supersonic expansion, provides detailed information on the energetics and vibrational structure of the first excited singlet state (S-1) of isocyanic acid (HNCO). Dissociation of molecules prepared in individual vibrational states by stimulated Raman excitation probes vibrational levels near the origin of the electronically excited state. Detection of fluorescence from dissociation products formed by multiphoton excitation through S-1 of molecules cooled in a supersonic expansion reveals the vibrational structure at higher energies. Both types of spectra show long, prominent progressions in the N-C-O bending vibration built on states with different amounts of N-C stretching excitation and H-N-C bending excitation. Analyzing the spectra locates the origin of the S-1 state at 32 449 +/- 20 cm(-1) and determines the harmonic vibrational frequencies of the N-C stretch (omega(3)=1034 +/- 20 cm(-1)), the H-N-C bend (omega(4)=1192 +/- 19 cm(-1)), and the N-C-O bend (omega(5)=599 +/- 7 cm(-1)), values that are consistent with several ab initio calculations. The assigned spectra strongly suggest that the N-C stretching vibration is a promoting mode for internal conversion from S-1 to S-0. (C) 2000 American Institute of Physics. [S0021-9606(00)00212-9]. C1 Univ Wisconsin, Dept Chem, Madison, WI 53706 USA. Univ So Calif, Dept Chem, Los Angeles, CA 90089 USA. RP Berghout, HL (reprint author), Univ Calif Los Alamos Natl Lab, MS C920,DX 2, Los Alamos, NM 87545 USA. NR 48 TC 10 Z9 10 U1 0 U2 9 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 15 PY 2000 VL 112 IS 15 BP 6678 EP 6688 DI 10.1063/1.481242 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 301EV UT WOS:000086297000021 ER PT J AU He, G Tokue, I Macdonald, RG AF He, G Tokue, I Macdonald, RG TI Rotational and translational energy distributions of CN(v=0,J) from the hot atom reactions: H+XCN -> HX+CN(v=0,J), where X=Br, Cl, and CN SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID VIBRATIONALLY EXCITED HCN; BIMOLECULAR REACTIONS; REACTION-PRODUCTS; REACTION DYNAMICS; TRANSITION-STATE; HYDROGEN-ATOMS; RED SYSTEM; 193 NM; DISSOCIATION; PHOTOLYSIS AB The dynamics of the reactions of translationally energetic H atoms with BrCN, ClCN, and (CN)(2) was studied by determining both the rotational state distribution and the translational energy disposition of the CN product ground vibrational level. The reaction was carried out using H atoms with a most probable translational energy of 92 kJ mol(-1). The CN radical was monitored by time- and frequency-resolved absorption spectroscopy using the CN red system (A (2)Pi <-- X (2)Sigma) (2,0) band near 790 nm. Sub-Doppler resolution spectroscopy was used to determine the initial translational temperature of the CN(0,J) product. The fraction of the available reaction exothermicity that appeared as CN(0) rotational energy, f(R), for H+XCN --> HX+CN was 0.034 +/- 0.006, 0.061 +/- 0.02, and 0.13 +/- 0.007, for X=Br, Cl, and CN, respectively. Likewise, the fraction of the available reaction exothermicity that appeared as relative product translational energy, f(T), was 0.52 +/- 0.25, 0.52 +/- 0.20, and 0.59 +/- 0.05, for X=Br, Cl, and CN, respectively. The absolute reaction cross sections for the H+XCN --> HX+CN reactions were also measured to be 0.03, 0.02, and 0.3x10(-16) cm(2) for X=Br, Cl, and CN, respectively. (C) 2000 American Institute of Physics. [S0021-9606(00)01115-6]. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Niigata Univ, Fac Sci, Dept Chem, Niigata 95021, Japan. RP He, G (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 50 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 15 PY 2000 VL 112 IS 15 BP 6689 EP 6699 DI 10.1063/1.481243 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 301EV UT WOS:000086297000022 ER PT J AU Geller, JT Holman, HY Su, G Conrad, ME Pruess, K Hunter-Cevera, JC AF Geller, JT Holman, HY Su, G Conrad, ME Pruess, K Hunter-Cevera, JC TI Flow dynamics and potential for biodegradation of organic contaminants in fractured rock vadose zones SO JOURNAL OF CONTAMINANT HYDROLOGY LA English DT Article DE unsaturated zone; fractures; biodegradation; volatile organic compounds; non-aqueous phase liquids; multiphase flow ID PETROLEUM-HYDROCARBONS; SUBSURFACE; BIOFILMS; LIQUIDS; WATER AB We present an experimental approach for investigating the potential for bioremediation of volatile organic compounds (VOCs) in fractured rock vadose zones. The experimental work was performed with rock Samples and indigenous microocganisms from the site of the United States Department of Energy's Idaho National Engineering and Environmental Laboratory (INEEL), located in a basalt flow basin where VOC contamination threatens the Snake River Aquifer. Our approach has four components: (1) establishing a conceptual model for fluid and contaminant distribution in the geologic matrix of interest; (2) identification of important features of liquid distribution by means of seepage experiments in the fracture plane; (3) identification of the presence and activity of microorganisms by non-destructive monitoring of biotransformations on rock surfaces at the micron-scale; and (4) integration of flow and biological activity in natural rock "geocosms". Geocosms are core-scale flow cells that incorporate some aspects of natural conditions, such as liquid seepage in the fracture plane and moisture content. Fluid flow and distribution within fracture networks may be a significant factor in the ability of microorganisms to degrade VOCs, as they affect the availability of substrate, moisture and nutrients. Flow visualization and tracer breakthrough curves in transparent fracture replicas for unsaturated inlet conditions exhibited the channelized and intermittent nature of liquid seepage, The seepage of water and non-aqueous phase liquids (NAPLs) of varying physical and chemical properties into an initially dry replica showed only subtle differences in liquid distribution. In contrast, the seepage of a NAPL into the fracture replica containing residual water resulted in complex trapping of NAPL alone the solid/water/air contact lines and diversion of NAPL to previously dry parts of the fracture. We found that a mixed culture of viable bacteria exists on the natural ruck surfaces. Microbial activity measurably changed in response to changing relative humidity (RH). Biological activity in the geocosm produced changes in liquid surface tension and seepage patterns over time. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, EO Lawrence Natl Lab, Div Earth Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Civil Engn, Berkeley, CA 94720 USA. RP Geller, JT (reprint author), Univ Calif Berkeley, EO Lawrence Natl Lab, Div Earth Sci, 1 Cyclotron Rd,MS90-1116, Berkeley, CA 94720 USA. RI Conrad, Mark/G-2767-2010; Holman, Hoi-Ying/N-8451-2014 OI Holman, Hoi-Ying/0000-0002-7534-2625 NR 50 TC 19 Z9 22 U1 1 U2 13 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7722 J9 J CONTAM HYDROL JI J. Contam. Hydrol. PD APR 15 PY 2000 VL 43 IS 1 BP 63 EP 90 DI 10.1016/S0169-7722(99)00095-9 PG 28 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA 299LW UT WOS:000086200900004 ER PT J AU Teeter, K Naeemuddin, M Gasperini, R Zimmerman, E White, KP Hoskins, R Gibson, G AF Teeter, K Naeemuddin, M Gasperini, R Zimmerman, E White, KP Hoskins, R Gibson, G TI Haplotype dimorphism in a SNP collection from Drosophila melanogaster SO JOURNAL OF EXPERIMENTAL ZOOLOGY LA English DT Article ID QUANTITATIVE TRAIT LOCI; DNA-SEQUENCES; POLYMORPHISMS; RECOMBINATION; ASSOCIATIONS; POPULATIONS; DIVERGENCE; ARRAYS; TOOL AB A moderate resolution single nucleotide polymorphism (SNP) map of the genome of Drosophila melanogaster that is designed for use in quantitative genetic mapping is described. Seventeen approximately 500 nucleotide gene sequences spaced at 10 to 20 centimorgan intervals were combined with 49 shorter sequence tag sites (STSs) at 5 to 10 centimorgan intervals to generate a map that should not leave any gaps greater than one half of a chromosome arm when any two wild type lines are compared. Of 20 markers with sufficient polymorphism to construct haplotype cladograms, 13 showed evidence for two divergent classes of haplotype. The possible mechanisms for and implications of the unexpected finding that two thirds of all short gene sequences in D. melanogaster may be dimorphic are discussed, including the suggestion that admixture between two separate lineages may have been a major event in the history of the species. (C) 2000 Wiley-Liss, Inc. C1 N Carolina State Univ, Dept Genet, Raleigh, NC 27695 USA. Univ Michigan, Dept Biol, Ann Arbor, MI 48109 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley Drosophila Genome Project, Berkeley, CA 94720 USA. Stanford DNA Sequencing & Technol Ctr, Dept Biochem, Palo Alto, CA 94306 USA. RP Gibson, G (reprint author), N Carolina State Univ, Dept Genet, Gardiner Hall, Raleigh, NC 27695 USA. RI Gasperini, Rob/J-7804-2014 NR 32 TC 29 Z9 30 U1 0 U2 0 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0022-104X J9 J EXP ZOOL JI J. Exp. Zool. PD APR 15 PY 2000 VL 288 IS 1 BP 63 EP 75 DI 10.1002/(SICI)1097-010X(20000415)288:1<63::AID-JEZ7>3.0.CO;2-1 PG 13 WC Zoology SC Zoology GA 301NY UT WOS:000086317300007 PM 10750054 ER PT J AU Bennett, TA Edwards, BS Sklar, LA Rogelj, S AF Bennett, TA Edwards, BS Sklar, LA Rogelj, S TI Sulfhydryl regulation of L-selectin shedding: Phenylarsine oxide promotes activation-independent L-selectin shedding from leukocytes SO JOURNAL OF IMMUNOLOGY LA English DT Article ID PROTEIN-DISULFIDE-ISOMERASE; NEUTROPHIL AGGREGATION; ADHESION MOLECULE; DEFICIENT MICE; CROSS-LINKING; IN-VITRO; TYROSINE PHOSPHORYLATION; STRUCTURAL REQUIREMENTS; AFFINITY-CHROMATOGRAPHY; SIGNAL-TRANSDUCTION AB The L-selectin adhesion molecule mediates leukocyte recruitment to inflammatory sites and lymphocyte trafficking through the peripheral lymph nodes. In response to leukocyte activation, L-selectin is proteolytically released from the cell surface, disabling leukocytes from the subsequent L-selectin-dependent interactions. We have found that L-selectin shedding is sensitive to sulfhydryl chemistry; it is promoted by thiol-oxidizing or -blocking reagents and inhibited by reducing reagents. Phenylarsine oxide (PAO), a trivalent arsenical that interacts with vicinal dithiols, is most potent in inducing rapid shedding of L-selectin from isolated neutrophils, eosinophils, and lymphocytes as well as from neutrophils in whole blood. PAO does not cause cell activation, nor does it interfere with integrin function or alter the expression of several other cell Surface molecules at the low concentrations that induce L-selectin shedding, PAO is not required to enter the cell to induce L-selectin shedding. TAPI-2 ((N-(D,L-[2-(hydroxyaminocarbonyl)-methyl]-4-methylpentanoyl)-L-3-(tert-butyl)-alanyl-L-alanine, 2-aminoethyl amide), which has previously been shown to inhibit the activation dependent L-selectin shedding, is also capable of inhibiting PAO-induced L-selectin shedding. We hypothesize that PAO-induced L-selectin shedding involves a regulatory molecule, such as protein disulfide isomerase (PDI), an enzyme that plays a role in the formation and rearrangement of disulfide bonds, contains PAO-binding, vicinal dithiol-active sites, and is expressed on the neutrophil surface. Cell surface expression of PDI, L-selectin shedding induced by PDI-blocking Abs and by bacitracin, a known inhibitor of PDI activity, and direct binding of PDI to PAO, provide supporting evidence for this hypothesis. C1 Univ New Mexico, Sch Med, Dept Pathol, Div Cytometry,Canc Res Facil, Albuquerque, NM 87131 USA. Univ Calif Los Alamos Natl Lab, Natl Flow Cytometry Resource, Los Alamos, NM 87545 USA. RP Rogelj, S (reprint author), New Mexico Inst Min & Technol, Dept Biol, Jones Annex Room 315, Socorro, NM 87801 USA. FU NCRR NIH HHS [R01RR14175]; NHLBI NIH HHS [HL56384] NR 73 TC 72 Z9 74 U1 0 U2 0 PU AMER ASSOC IMMUNOLOGISTS PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0022-1767 J9 J IMMUNOL JI J. Immunol. PD APR 15 PY 2000 VL 164 IS 8 BP 4120 EP 4129 PG 10 WC Immunology SC Immunology GA 303GZ UT WOS:000086415300025 PM 10754306 ER PT J AU Fu, Q Cribb, MC Barker, HW Krueger, SK Grossman, A AF Fu, Q Cribb, MC Barker, HW Krueger, SK Grossman, A TI Cloud geometry effects on atmospheric solar absorption SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID RADIATIVE-TRANSFER; STRATOCUMULUS CLOUDS; NUMERICAL-SIMULATION; INDEPENDENT PIXEL; BOUNDARY-LAYER; BLACK CARBON; ALBEDO; BUDGET; MODEL; PARAMETERIZATIONS AB A 3D broadband solar radiative transfer scheme is formulated by integrating a Monte Carlo photon transport algorithm with the Fu-Liou radiation model, it is applied to fields of tropical mesoscale convective clouds and subtropical marine boundary layer clouds that were generated by a 2D cloud-resolving model. The effects of cloud geometry on the radiative energy budget are examined by comparing the full-resolution Monte Carlo results with those from the independent column approximation (ICA) that applies the plane-parallel radiation model to each column. For the tropical convective cloud system, it is found that cloud geometry effects always enhance atmospheric solar absorption regardless of solar zenith angle. In a large horizontal domain (512 km). differences in domain-averaged atmospheric absorption between the Monte Carlo and the ICA are less than 4 W m(2) in the daytime. However. for a smaller domain (e.g., 75 km) containing a cluster of deep convective towers, domain-averaged absorption can be enhanced by more than 20 W m(-2). For a subtropical marine boundary layer cloud system during the status-to-cumulus transition, calculations show that the ICA webs very well fur domain-averaged fluxes of the stratocumulus cloud fields even for a very small domain (4.8 km). For the trade cumulus cloud field, the effects of cloud sides and horizontal transport of photons become more significant. Calculations have also been made for both cloud systems including black carbon aerosol and a water vapor continuum. It is found that cloud geometry products no discernible effects on the absorption enhancement due to the black carbon aerosol and water vapor continuum. The current study indicates that the atmospheric absorption enhancement due to cloud-related 3D photon transport is small. This enhancement could nor explain the excess absorption suggested by recent studies. C1 Dalhousie Univ, Dept Oceanog, Atmospher Sci Program, Halifax, NS B3H 4J1, Canada. Atmospher Environm Serv, Downsview, ON, Canada. Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. Univ Calif Lawrence Livermore Natl Lab, Div Atmospher Sci, Livermore, CA USA. RP Fu, Q (reprint author), Dalhousie Univ, Dept Oceanog, Atmospher Sci Program, Halifax, NS B3H 4J1, Canada. RI Cribb, Maureen/K-1341-2013 OI Cribb, Maureen/0000-0002-9745-3676 NR 41 TC 43 Z9 44 U1 0 U2 4 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 APR 15 PY 2000 VL 57 IS 8 BP 1156 EP 1168 DI 10.1175/1520-0469(2000)057<1156:CGEOAS>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 306HU UT WOS:000086591900011 ER PT J AU Parlett, BN Marques, OA AF Parlett, BN Marques, OA TI An implementation of the dqds algorithm (positive case) SO LINEAR ALGEBRA AND ITS APPLICATIONS LA English DT Article; Proceedings Paper CT International Workshop on Accurate Solution of Eigenvalue Problems CY JUL 20-23, 1998 CL PENN STATE UNIV, STATE COLL, UNIVERSITY PK, PENNSYLVANIA SP Penn State Univ, State Coll HO PENN STATE UNIV, STATE COLL ID ACCURATE SINGULAR-VALUES; FLOWS AB The dqds algorithm was introduced in 1994 to compute singular values of bidiagonal matrices to high relative accuracy but it may also be used to compute eigenvalues of tridiagonal matrices. This paper discusses in detail the issues that have to be faced when the algorithm is to be realized on a computer: criteria for accepting a value, for splitting the matrix, and for choosing a shift to reduce the number of iterations, as well as the relative advantages of using IEEE arithmetic when available. Ways to avoid unnecessary over/underflows are described. In addition some new formulae are developed to approximate the smallest eigenvalue from a twisted factorization of a matrix. The results of extensive testing are presented at the end. The list of contents is a valuable guide to the reader interested in specific features of the algorithm. (C) 2000 Elsevier Science Inc. All rights reserved. C1 Univ Calif Berkeley, Dept Math, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept EECS, Div Comp Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Natl Energy Res Sci Comp Ctr, Berkeley, CA 94720 USA. RP Parlett, BN (reprint author), Univ Calif Berkeley, Dept Math, Berkeley, CA 94720 USA. NR 13 TC 35 Z9 35 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0024-3795 J9 LINEAR ALGEBRA APPL JI Linear Alg. Appl. PD APR 15 PY 2000 VL 309 IS 1-3 BP 217 EP 259 DI 10.1016/S0024-3795(00)00010-0 PG 43 WC Mathematics, Applied; Mathematics SC Mathematics GA 304JE UT WOS:000086479400013 ER PT J AU Jankowiak, R Roberts, K Tomasik, P Sikora, M Small, GJ Schilling, CH AF Jankowiak, R Roberts, K Tomasik, P Sikora, M Small, GJ Schilling, CH TI Probing the crystalline environment of alpha-alumina via luminescence of metal ion impurities: an optical method of ceramic flaw detection SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE luminescence; alumina; density gradients; fluorescence; cracks; green body ID SPECTROSCOPY; FLUORESCENCE; RUBY; STRESSES; POWDERS AB Optical studies of W-excited, polycrystalline alpha-alumina were performed as a function of the sintering temperature. The luminscence intensity in the 600-750 nm region increased with alumina density and originated from trace amounts of Cr3+ impurities residing in two different sites, labeled A and B. Since trace amounts of Cr3+ exist in most aluminas that are used in commercial applications, this luminescent methodology has promise as a simple, nondestructive tool for detecting packing-density-gradients and microcracks in alumina-based ceramics at different stages of shape-forming and sintering. In high-density alumina, at T = 300 K, sites A emit sharp R-1/R-2-lines at 14407.5/14436.5 cm(-1) with Delta E(R-2 - R-1) splitting of similar to 30 cm(-1), indicating a ruby-like high-field crystalline environment. The lower symmetry sites (B) are characterized by higher-energy, presumably E-2 --> (4)A(2) doublet transitions (at 14746.7 cm(-1) and similar to 14818 cm(-1)) and E-2 splitting of similar to 71 cm(-1). The larger splitting is attributed to anisotropy in the electron repulsion energy for Cr3+ ions residing in slightly larger volumes of the CrO6 and/or due to tetragonal crystal symmetry distortion. Luminescence from B sites is revealed for the first time; excitation using an argon-ion laser at 514.5 nm only reveals luminescence from A sites. UV-excited, luminescence based density calibration curves and density-dependent, color images of alumina samples, along with methodologies for density gradient mapping and microcrack detection, are described. It is shown that density gradients and microcracks can be visualized either by imaging the inherent luminescence of cc-alumina or by fluorescence from an appropriate staining dye. Published by Elsevier Science S.A. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Univ Agr, Dept Chem, PL-31120 Krakow, Poland. Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. RP Schilling, CH (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 31 TC 18 Z9 18 U1 0 U2 5 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 APR 15 PY 2000 VL 281 IS 1-2 BP 45 EP 55 DI 10.1016/S0921-5093(99)00749-2 PG 11 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 293ZF UT WOS:000085884600007 ER PT J AU Hong, SI Hill, MA AF Hong, SI Hill, MA TI Microstructural stability of Cu-Nb microcomposite wires fabricated by the bundling and drawing process SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE TEM; copper matrix; niobium; bundling process ID WORKED INSITU COMPOSITES; IN-SITU COMPOSITES; PERCENT CR ALLOY; ELECTRICAL-CONDUCTIVITY; INTERPHASE BARRIER; STRENGTH; DEFORMATION; STRAINS; POWDERS; MAGNETS AB The microstructural stability of Cu-Nb microcomposite wires fabricated by the bundling and drawing process was examined using TEM (Transmission Electron Microscopy). No flaws were observed near the interface regions between the bundled wires and the copper can, suggesting excellent bonding. Nb filaments were randomly distributed throughout the copper matrix and appeared straight or slightly curved in the bundled wires. The absence of heavily kinked filaments in the bundled wires is attributed to the break-up and cylinderization of niobium filaments during the bundling process. Niobium filaments were dissolved and numerous niobium precipitates formed in the copper matrix during high temperature bundling process. Twin bands were observed in the Cu-Nb, with the Nb filaments acting as barriers to twin propagation. Occasionally, the copper matrix on either side of the Nb filaments was found to have different texture components, which is thought to result from the reorientation of [111] into near [200] by twinning. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Chungnam Natl Univ, Dept Met Engn, Taejon 305764, South Korea. Univ Calif Los Alamos Natl Lab, Div Mat Sci, Los Alamos, NM 87545 USA. RP Hong, SI (reprint author), Chungnam Natl Univ, Dept Met Engn, Taedok Sci Town, Taejon 305764, South Korea. NR 43 TC 36 Z9 44 U1 1 U2 11 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 APR 15 PY 2000 VL 281 IS 1-2 BP 189 EP 197 PG 9 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 293ZF UT WOS:000085884600024 ER PT J AU Robinson, H Gao, YG Sanishvili, R Joachimiak, A Wang, AHJ AF Robinson, H Gao, YG Sanishvili, R Joachimiak, A Wang, AHJ TI Hexahydrated magnesium ions bind in the deep major groove and at the outer mouth of A-form nucleic acid duplexes SO NUCLEIC ACIDS RESEARCH LA English DT Article ID PHENYLALANINE TRANSFER-RNA; B-DNA; CRYSTAL-STRUCTURE; STABILIZATION; ACCESSIBILITY; RESOLUTION; SPERMINE; MOTIFS; SPINE AB Magnesium ions play important roles in the structure and function of nucleic acids, Whereas the tertiary folding of RNA often requires magnesium ions binding to tight places where phosphates are clustered, the molecular basis of the interactions of magnesium ions with RNA helical regions is less well understood. We have refined the crystal structures of four decamer oligonucleotides, d(ACCGGCCGGT), r(GCG)d(TATACGC), r(GC)d(GTATACGC) and r(G)d(GCGTATACGC) with bound hexahydrated magnesium ions at high resolution. The structures reveal that A-form nucleic acid has characteristic [Mg(H2O)(6)](2+) binding modes. One mode has the ion binding in the deep major groove of a GpN step at the O6/N7 sites of guanine bases via hydrogen bonds, Our crystallographic observations are consistent with the recent NMR observations that in solution [Co(NH3)(6)](3+), a model ion of [Mg(H2O)(6)](2+), binds in an identical manner, The other mode involves the binding of the ion to phosphates, bridging across the outer mouth of the narrow major groove. These [Mg(H2O)(6)](2+) ions are found at the most negative electrostatic potential regions of A-form duplexes. We propose that these two binding modes are important in the global charge neutralization, and therefore stability, of A-form duplexes. C1 Univ Illinois, Dept Cell & Struct Biol, Urbana, IL 61801 USA. Argonne Natl Lab, Biosci Div, Struct Biol Ctr, 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, B107 CLSL,601 S Goodwin Ave, Urbana, IL 61801 USA. FU NIGMS NIH HHS [GM-41612] NR 31 TC 52 Z9 53 U1 3 U2 9 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0305-1048 J9 NUCLEIC ACIDS RES JI Nucleic Acids Res. PD APR 15 PY 2000 VL 28 IS 8 BP 1760 EP 1766 DI 10.1093/nar/28.8.1760 PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 308FG UT WOS:000086699400012 PM 10734195 ER PT J AU Robinson, H Gao, YG Sanishvili, R Joachimiak, A Wang, AHJ AF Robinson, Howard Gao, Yi-Gui Sanishvili, Ruslan Joachimiak, Andrzej Wang, Andrew H. -J. TI Hexahydrated magnesium ions bind in the deep major groove and at the outer mouth of A-form nucleic acid duplexes SO NUCLEIC ACIDS RESEARCH LA English DT Article ID PHENYLALANINE TRANSFER-RNA; B-DNA; MOLECULAR-STRUCTURE; CRYSTAL-STRUCTURES; BASE-PAIR; RESOLUTION; STABILIZATION; ACCESSIBILITY; SPERMINE; RIBOZYME AB Magnesium ions play important roles in the structure and function of nucleic acids. Whereas the tertiary folding of RNA often requires magnesium ions binding to tight places where phosphates are clustered, the molecular basis of the interactions of magnesium ions with RNA helical regions is less well understood. We have refined the crystal structures of four decamer oligonucleotides, d(ACCGGCCGGT), r(GCG)d(TATACGC), r(GC)d(GTATACGC) and r(G)d(GCGTATACGC) with bound hexahydrated magnesium ions at high resolution. The structures reveal that A-form nucleic acid has characteristic [Mg(H2O)(6)](2+) binding modes. One mode has the ion binding in the deep major groove of a GpN step at the O6/N7 sites of guanine bases via hydrogen bonds. Our crystallographic observations are consistent with the recent NMR observations that in solution [Co(NH3)(6)](3+), a model ion of [Mg(H2O)(6)](2+), binds in an identical manner. The other mode involves the binding of the ion to phosphates, bridging across the outer mouth of the narrow major groove. These [Mg(H2O)(6)](2+) ions are found at the most negative electrostatic potential regions of A-form duplexes. We propose that these two binding modes are important in the global charge neutralization, and therefore stability, of A-form duplexes. C1 [Robinson, Howard; Gao, Yi-Gui; Wang, Andrew H. -J.] Univ Illinois, Dept Cell & Struct Biol, CLSL Bl07, Urbana, IL 61801 USA. [Sanishvili, Ruslan; Joachimiak, Andrzej] Argonne Natl Lab, Struct Biol Ctr, Biosci Div, Argonne, IL 60439 USA. [Joachimiak, Andrzej] Northwestern Univ, Dept Biochem Mol Biol & Cell Biol, Evanston, IL 60208 USA. RP Wang, AHJ (reprint author), Univ Illinois, Dept Cell & Struct Biol, CLSL Bl07, 601 S Goodwin Ave, Urbana, IL 61801 USA. EM ahjwang@uiuc.edu FU NIH [GM-41612]; NSF [MCB98-08298]; US Department of Energy, Basic Energy Sciences, Office of Science [W-31-109-Eng-38] FX This work was supported by a NIH grant (GM-41612) and a NSF grant (MCB98-08298) to A.H.-J.W. and by the US Department of Energy, Basic Energy Sciences, Office of Science, under contract W-31-109-Eng-38 to A.J. NR 31 TC 52 Z9 53 U1 3 U2 9 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0305-1048 J9 NUCLEIC ACIDS RES JI Nucleic Acids Res. PD APR 15 PY 2000 VL 28 IS 8 BP 1760 EP 1766 DI 10.1093/nar/28.8.1760 PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA V17CX UT WOS:000207916400022 PM 10734195 ER PT J AU Hsieh, HB Wang, M Lersch, RA Kim, UJ Weier, HUG AF Hsieh, Huangpin B. Wang, Mei Lersch, Robert A. Kim, Ung-Jin Weier, Heinz-Ulrich G. TI Rational design of landmark probes for quantitative DNA fiber mapping (QDFM) SO NUCLEIC ACIDS RESEARCH LA English DT Article AB Rapid construction of high-resolution physical maps requires accurate information about overlap between DNA clones and the size of gaps between clones or clone contigs. We recently developed a procedure termed 'quantitative DNA fiber mapping' (QDFM) to help construct physical maps by measuring the overlap between clones or the physical distance between non-overlapping contigs. QDFM is based on hybridization of non-isotopically labeled probes onto DNA molecules that were bound to a solid support and stretched homogeneously to similar to 2.3 kb/mu m. In this paper, we describe the design of probes that bind specifically to the cloning vector of DNA recombinants to facilitate physical mapping. Probes described here delineate the most frequently used cloning vectors such as BACs, P1s, PACs and YACs. As demonstrated in representative hybridizations, vector-specific probes provide valuable information about molecule integrity, insert size and orientation as well as localization of hybridization domains relative to specifically-marked vector sequences. C1 [Hsieh, Huangpin B.; Wang, Mei; Lersch, Robert A.; Weier, Heinz-Ulrich G.] Univ Calif Berkeley, EO Lawrence Berkeley Natl Lab, Div Life Sci, Berkeley, CA 94720 USA. [Kim, Ung-Jin] CALTECH, Div Biol, Pasadena, CA 91125 USA. RP Weier, HUG (reprint author), Univ Calif Berkeley, EO Lawrence Berkeley Natl Lab, Div Life Sci, MS 74-157,1 Cyclotron Rd, Berkeley, CA 94720 USA. EM ugweier@lbl.gov FU Office of Energy Research, Office of Health and Environmental Research, US Department of Energy [DE-AC-03-76SF00098]; U.C. Systemwide Biotechnology Research and Education Program [S96-25]; Cancer Research Foundation of America FX This work was supported by a grant from the Director, Office of Energy Research, Office of Health and Environmental Research, US Department of Energy, under contract DE-AC-03-76SF00098, a training grant from the U.C. Systemwide Biotechnology Research and Education Program (S96-25) and a postdoctoral fellowship from the Cancer Research Foundation of America to H.B.H. NR 16 TC 3 Z9 3 U1 1 U2 1 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0305-1048 J9 NUCLEIC ACIDS RES JI Nucleic Acids Res. PD APR 15 PY 2000 VL 28 IS 8 AR e30 DI 10.1093/nar/28.8.e30 PG 5 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA V17CX UT WOS:000207916400003 PM 10734207 ER PT J AU Surzhikov, SA Timofeev, EN Chernov, BK Golova, JB Mirzabekov, AD AF Surzhikov, Sergey A. Timofeev, Edward N. Chernov, Boris K. Golova, Julia B. Mirzabekov, Andrei D. TI Advanced method for oligonucleotide deprotection SO NUCLEIC ACIDS RESEARCH LA English DT Article AB A new procedure for rapid deprotection of synthetic oligodeoxynucleotides has been developed. While all known deprotection methods require purification to remove the residual protective groups (e.g. benzamide) and insoluble silicates, the new procedure based on the use of an ammonia-free reagent mixture allows one to avoid the additional purification steps. The method can be applied to deprotect the oligodeoxy-nucleotides synthesized by using the standard protected nucleoside phosphoramidites dG(iBu), dC(Bz) and dA(Bz). C1 [Mirzabekov, Andrei D.] Argonne Natl Lab, Biochip Technol Ctr, Argonne, IL 60439 USA. Russian Acad Sci, Engelhardt Inst Mol Biol, Joint Human Genome Program, Moscow 117984, Russia. RP Mirzabekov, AD (reprint author), Argonne Natl Lab, Biochip Technol Ctr, 9700 S Cass Ave, Argonne, IL 60439 USA. EM amir@everest.bim.anl.gov FU Argonne National Laboratory [9701902]; Motorolla and Packard Instruments; Defense Advanced Research Project Agency [AO-E428]; Russian Human Genome Program [123/97]; Russian Foundation of Fundamental Research [96-04-49858] FX We thank E. Novikova and C. Kaicher for editorial assistance. This work was supported by the Cooperative Research and Development Agreement 9701902 between Argonne National Laboratory, Motorolla and Packard Instruments, the Defense Advanced Research Project Agency under Interagency Agreement no. AO-E428, the Russian Human Genome Program under Grant 123/97 and the Russian Foundation of Fundamental Research under Grant 96-04-49858. NR 15 TC 10 Z9 10 U1 1 U2 5 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0305-1048 J9 NUCLEIC ACIDS RES JI Nucleic Acids Res. PD APR 15 PY 2000 VL 28 IS 8 AR e29 DI 10.1093/nar/28.8.e29 PG 5 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA V17CX UT WOS:000207916400002 PM 10734206 ER PT J AU Aniolek, KW Schmitt, RL Kulp, TJ Richman, BA Bisson, SE Powers, PE AF Aniolek, KW Schmitt, RL Kulp, TJ Richman, BA Bisson, SE Powers, PE TI Microlaser-pumped periodically poled lithium niobate optical parametric generator-optical parametric amplifier SO OPTICS LETTERS LA English DT Article ID RODS AB For what is believed to be the first time, a single-longitudinal-mode passively Q-switched Nd:YAG microlaser is used to pump a narrow-bandwidth periodically poled lithium niobate (PPLN) optical parametric generator-optical parametric amplifier (OPG-OPA). Before amplification in the OPA, the output of the OPG stage was spectrally filtered with an air-spaced etalon, resulting in spectroscopically useful radiation (bandwidth, similar to 0.05 cm(-1) FWHM) that was tunable in 15-cm(-1) segments anywhere in the signal range 6820-6220 cm(-1) and the idler range 2580-3180 cm(-1). The ability to pump an OPG-OPA with compact, high-repetition-rate, intrinsically narrow-bandwidth microlasers is made possible by the high gain of PPLN. The result is a tunable light source that is well suited for use in portable spectroscopic gas sensors. (C) 2000 Optical Society of America. OCIS codes: 130.6010, 190.4410. C1 Sandia Natl Labs, Livermore, CA 94551 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Sandia Natl Labs, Livermore, CA 94551 USA. Univ Dayton, Dept Phys, Dayton, OH 45469 USA. RP Kulp, TJ (reprint author), Sandia Natl Labs, Livermore, CA 94551 USA. NR 6 TC 27 Z9 28 U1 0 U2 8 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 APR 15 PY 2000 VL 25 IS 8 BP 557 EP 559 DI 10.1364/OL.25.000557 PG 3 WC Optics SC Optics GA 304UD UT WOS:000086501800015 PM 18064110 ER PT J AU Maslov, S AF Maslov, S TI Simple model of a limit order-driven market SO PHYSICA A LA English DT Article AB We introduce and study a simple model of a limit order-driven market. Traders in this model can either trade stock (or any other risky asset for that matter) at the market price or place a limit order, i.e., an instruction to buy (sell) a certain amount of the stock if its price falls below (raises above) a predefined level. The choice between these two options is purely random (there are no strategies involved), and the execution price of a limit order is determined simply by offsetting the most recent market price by a random amount. Numerical simulations of this model revealed that despite such minimalistic rules the price pattern generated by this model has such realistic features as "fat" tails of the probability distribution of price fluctuations, characterized by a crossover between two power law exponents, long range correlations of the volatility, and a non-trivial Hurst exponent of the price signal. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Maslov, S (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 11 TC 95 Z9 98 U1 2 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4371 J9 PHYSICA A JI Physica A PD APR 15 PY 2000 VL 278 IS 3-4 BP 571 EP 578 DI 10.1016/S0378-4371(00)00067-4 PG 8 WC Physics, Multidisciplinary SC Physics GA 306ED UT WOS:000086583600021 ER PT J AU Kursumovic, A Berghuis, P Dediu, V Evetts, JE Matacotta, FC Wagner, GA AF Kursumovic, A Berghuis, P Dediu, V Evetts, JE Matacotta, FC Wagner, GA TI Thickness-dependent oxygenation in c-axis oriented REBa2Cu3O7-delta thin films deposited on closely matched substrates SO PHYSICA C LA English DT Article DE oxygen diffusion; YBaCuO; GdBaCuO; thin films; dislocations ID TRACER DIFFUSION; RESISTIVITY MEASUREMENTS; YBA2CU3O7-DELTA FILMS; SINGLE-CRYSTAL; YBA2CU3O6+X; BA2YCU3O7-DELTA; PRESSURE; INSITU AB Epitaxial c-axis oriented thin REBa2Cu3O7-delta films were deposited on closely matched substrates: YBa2Cu3O7-delta on SrTiO3 and GdBa2Cu3O7-delta on NdGaO3. Kinetics of oxygen in-diffusion was studied by resistivity changes during corresponding isothermal annealing in a reduced oxygen atmosphere. The rate of oxygen uptake was found to be dependent on film thickness, abruptly increasing after some critical film thickness of about 40 nm. The increase continued over several orders of magnitude, as the film gets thicker, saturating for a film thickness of about 500 nm. Atomic Force Microscopy (AFM) clearly illustrates the transition from a dislocation-free to dislocation-developed microstructure at around the critical film thickness. It is believed that these dislocations serve as easy paths for c-axis diffusion. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Cambridge, Dept Mat Sci, Cambridge CB2 3QZ, England. Irc Superconduct, Cambridge CB2 3QZ, England. Argonne Natl Lab, MSD, Argonne, IL 60439 USA. CNR, Inst Spettroscopia Mol, I-40129 Bologna, Italy. RP Kursumovic, A (reprint author), Univ Cambridge, Dept Mat Sci, Cambridge CB2 3QZ, England. RI DEDIU, Valentin/F-5365-2011 OI DEDIU, Valentin/0000-0001-9567-5112 NR 30 TC 5 Z9 5 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD APR 15 PY 2000 VL 331 IS 2 BP 185 EP 190 DI 10.1016/S0921-4534(00)00013-7 PG 6 WC Physics, Applied SC Physics GA 301KY UT WOS:000086310400011 ER PT J AU Zhang, Y Mascarenhas, A Smith, S Geisz, JF Olson, JM Hanna, M AF Zhang, Y Mascarenhas, A Smith, S Geisz, JF Olson, JM Hanna, M TI Effects of spontaneous ordering and alloy statistical fluctuations on exciton linewidth in GaxIn1-xP alloys SO PHYSICAL REVIEW B LA English DT Article ID PHOTOLUMINESCENCE-EXCITATION-SPECTROSCOPY; SEMICONDUCTOR ALLOYS; RADIATIVE TRANSITIONS; MIXED-CRYSTALS; GAINP2; GA0.52IN0.48P AB We experimentally demonstrate an intrinsic statistical effect of the phenomenon of spontaneous ordering in semiconductor alloys: the reduction of alloy fluctuations as a function of the order parameter, as reflected in the exciton linewidth. A theoretical model is presented to qualitatively describe the dependence of the exciton linewidth on the order parameter. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Zhang, Y (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. NR 27 TC 20 Z9 20 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 APR 15 PY 2000 VL 61 IS 15 BP 9910 EP 9912 DI 10.1103/PhysRevB.61.9910 PG 3 WC Physics, Condensed Matter SC Physics GA 306PZ UT WOS:000086606200017 ER PT J AU Cho, JH Kim, KS Lee, SH Kang, MH Zhang, ZY AF Cho, JH Kim, KS Lee, SH Kang, MH Zhang, ZY TI Origin of contrasting surface core-level shifts at the Be(10(1)over-bar0) and Mg(10(1)over-bar0) surfaces SO PHYSICAL REVIEW B LA English DT Article ID BE(0001) SURFACE; METAL-SURFACES; PSEUDOPOTENTIALS; RELAXATION; BERYLLIUM; ABINITIO; SPECTRUM; PHYSICS AB As expected, very similar oscillatory multilayer relaxations exist at the (10 (1) over bar 0) surfaces of the isoelectronic Be and Mg. But surprisingly, these two systems exhibit drastically different behaviors in the surface core-level shift (SCLS). For Be, our density-functional theory calculations show that the SCLS persists down to the fifth layer, and depends strongly on lattice relaxation and final-state effect. In contrast, for Mg only the atoms in the first layer have a small and insensitive SCLS. The physical origin of the disparate features in the SCLS can be traced to the different bending natures of the two elements in bulk form: strongly covalentlike for Be, and nearly free-electron-like for Mg. C1 Pohang Univ Sci & Technol, Ctr Superfunct Mat, Dept Chem, Pohang 790784, South Korea. Pohang Univ Sci & Technol, Dept Phys, Pohang 790784, South Korea. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Phys, Knoxville, TN USA. RP Pohang Univ Sci & Technol, Ctr Superfunct Mat, Dept Chem, Pohang 790784, South Korea. EM cho@chem.postech.ac.kr RI Kim, Kwang/C-7538-2012; Lee, Sung-Hoon/A-9582-2011; Cho, Jun-Hyung/R-7256-2016 OI Kim, Kwang/0000-0002-6929-5359; Lee, Sung-Hoon/0000-0002-8553-8007; Cho, Jun-Hyung/0000-0002-1785-1835 NR 28 TC 22 Z9 22 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 APR 15 PY 2000 VL 61 IS 15 BP 9975 EP 9978 DI 10.1103/PhysRevB.61.9975 PG 4 WC Physics, Condensed Matter SC Physics GA 306PZ UT WOS:000086606200034 ER PT J AU Jamneala, T Madhavan, V Chen, W Crommie, MF AF Jamneala, T Madhavan, V Chen, W Crommie, MF TI Scanning tunneling spectroscopy of transition-metal impurities at the surface of gold SO PHYSICAL REVIEW B LA English DT Article ID ELECTRONIC-STRUCTURE; MAGNETIC-IMPURITIES; 3D; MODEL; ATOM; PHOTOEMISSION; RESONANCE; ALLOYS; 4D AB The magnetic properties of an impurity atom vary greatly depending on the nature of the impurity d level. We have used scanning tunneling spectroscopy to systematically probe the local electronic structure of individual transition-metal impurities having different d-level configurations. Atoms from the 3d row of the periodic table wen adsorbed onto a Au(111) substrate and spectroscopically probed with an ultrahigh vacuum scanning tunneling microscope at a temperature of 6 K. Elements near the center of the 3d row (V, Cr, Mn, and Fe) displayed featureless electronic structure over the energy range studied, while elements near the ends of the row (Ti, Co, and Ni) showed narrow resonances near the Fermi energy. These spectroscopic features are interpreted as a combination of the Kondo resonance and bare d resonance, and are consistent with trends observed in the Kondo temperature of bulk impurities. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Chen, W (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NR 32 TC 82 Z9 84 U1 0 U2 32 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 APR 15 PY 2000 VL 61 IS 15 BP 9990 EP 9993 DI 10.1103/PhysRevB.61.9990 PG 4 WC Physics, Condensed Matter SC Physics GA 306PZ UT WOS:000086606200038 ER PT J AU Lee, SJ Hong, SY Fisher, IR Canfield, PC Harmon, BN Lynch, DW AF Lee, SJ Hong, SY Fisher, IR Canfield, PC Harmon, BN Lynch, DW TI Optical properties and electronic structure of single crystals of EuAl2 and YbAl2 SO PHYSICAL REVIEW B LA English DT Article ID RARE-EARTH METALS; SPECTROSCOPIC ELLIPSOMETRY; CEAL2; LAAL2; LUAL2; YAL2 AB The optical conductivities of single crystals of LuAl2 and YbAl2 were measured by spectroscopic ellipsometry in the energy range of 1.4-5.5 eV for LuAl2 and 1.4-5.2 eV for YbAl2. The optical conductivity spectra of LuAl2 and YbAl2 show similar features except for a difference in magnitude. Both have peaks near 1.8-2.1 eV and broad shoulders between 3.0 and 4.0 eV. The shoulder is weaker in YbAl2. The band structure, density of states, and optical conductivity were calculated with the tight-binding linear muffin-tin orbital method in the atomic sphere approximation. The calculated optical conductivity with the inclusion of energy-dependent broadening agrees well with the experimental data. Oxidation effects on the surface of the sample were modeled using a three-phase model. The calculated optical conductivity of the clean surface is enhanced over that of the oxidized surface. C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames, IA 50011 USA. Kongju Natl Univ, Dept Phys, Kongju 314701, Chungnam, South Korea. RP Hong, SY (reprint author), Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. RI Canfield, Paul/H-2698-2014 NR 45 TC 17 Z9 17 U1 1 U2 13 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 2000 VL 61 IS 15 BP 10076 EP 10083 DI 10.1103/PhysRevB.61.10076 PG 8 WC Physics, Condensed Matter SC Physics GA 306PZ UT WOS:000086606200051 ER PT J AU Ghosh, VJ Alatalo, M Asoka-Kumar, P Nielsen, B Lynn, KG Kruseman, AC Mijnarends, PE AF Ghosh, VJ Alatalo, M Asoka-Kumar, P Nielsen, B Lynn, KG Kruseman, AC Mijnarends, PE TI Calculation of the Doppler broadening of the electron-positron annihilation radiation in defect-free bulk materials SO PHYSICAL REVIEW B LA English DT Article ID ELEMENTAL SPECIFICITY; MOMENTUM DISTRIBUTION; VACANCY DEFECTS; SOLIDS; CORE; IDENTIFICATION; SI; SPECTROSCOPY; LIFETIMES; SURFACES AB Results of a calculation of the Doppler broadening of the positron-electron annihilation radiation and positron Lifetimes in a large number of elemental defect-free materials an presented. A simple scheme based on the method of superimposed atoms is used for these calculations. Calculated values of the Doppler broadening are compared with experimental data for a number of elemental materials, and qualitative agreement is obtained. These results provide a database which can be used for characterizing materials and identifying impurity-vacancy complexes. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Helsinki, Helsinki Inst Phys, Helsinki 02015, Finland. Univ Helsinki, Phys Lab, Helsinki 02015, Finland. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Washington State Univ, Ctr Mat Res, Pullman, WA 99163 USA. Delft Univ Technol, Interfac Reactor Inst, NL-2629 JB Delft, Netherlands. RP Kruseman, AC (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. RI Nielsen, Bent/B-7353-2009 OI Nielsen, Bent/0000-0001-7016-0040 NR 32 TC 58 Z9 63 U1 0 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 2000 VL 61 IS 15 BP 10092 EP 10099 DI 10.1103/PhysRevB.61.10092 PG 8 WC Physics, Condensed Matter SC Physics GA 306PZ UT WOS:000086606200053 ER PT J AU Magri, R Wang, LW Zunger, A Vurgaftman, I Meyer, JR AF Magri, R Wang, LW Zunger, A Vurgaftman, I Meyer, JR TI Anticrossing semiconducting band gap in nominally semimetallic InAs/GaSb superlattices SO PHYSICAL REVIEW B LA English DT Article ID GASB SUPER-LATTICES; OPTICAL ANISOTROPY; ELECTRONIC-STRUCTURE; QUANTUM DOTS; LIGHT-HOLE; HETEROSTRUCTURES; TRANSITION; INTERFACES; STATES AB While (InAs)(n)/(GaSb)(n) (001) superlattices are semiconducting for nn(c) the InAs electron level e(InAs) is below the GaSb hole level h(GaSb), so the system is converted to a nominal semimetal. At nonzero in-plane wave vectors (k(parallel to)not equal 0), however, the wave functions e(InAs) and h(GaSb) have the same symmetry, so they anticross. This opens up a "hybridization gap'' at some k(parallel to)=k(parallel to)*. Using a pseudopotential plane-wave approach as well as a (pseudopotential fit) eight-band k.p approach, we predict the hybridization gap and its properties such as wave-function localization and out-of-plane dispersion. We find that recent model calculations underestimate this gap severely. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. USN, Res Lab, Washington, DC 20375 USA. RP Magri, R (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Zunger, Alex/A-6733-2013; Magri, Rita/O-5267-2016 OI Magri, Rita/0000-0003-2945-0374 NR 33 TC 36 Z9 36 U1 3 U2 11 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 2000 VL 61 IS 15 BP 10235 EP 10241 DI 10.1103/PhysRevB.61.10235 PG 7 WC Physics, Condensed Matter SC Physics GA 306PZ UT WOS:000086606200072 ER PT J AU Ganichev, SD Ziemann, E Prettl, W Yassievich, IN Istratov, AA Weber, ER AF Ganichev, SD Ziemann, E Prettl, W Yassievich, IN Istratov, AA Weber, ER TI Distinction between the Poole-Frenkel and tunneling models of electric-field-stimulated carrier emission from deep levels in semiconductors SO PHYSICAL REVIEW B LA English DT Article ID FAR-INFRARED RADIATION; ENHANCED EMISSION; GOLD ACCEPTOR; IONIZATION; SILICON; TRAPS; CONDUCTION; GENERATION; CENTERS; CHARGE AB The enhancement of the emission rate of charge carriers from deep-level defects in electric field is routinely used to determine the charge state of the defects. However, only a limited number of defects can be satisfactorily described by the Poole-Frenkel theory. An electric field dependence different from that expected fr om the Poole-Frenkel theory has been repeatedly reported in the literature, and no unambiguous identification of the charge state of the defect could be made. In this article, the electric field dependencies of emission of carriers from DX centers in A1(x)Ga(1-x)As:Te, Cu pairs in silicon, and Ge:Hg have been studied applying static and terahertz electric fields, and analyzed by using the models of Poole-Frenkel and phonon assisted tunneling. It is shown that phonon assisted tunneling and Poole-Frenkel emission are two competitive mechanisms of enhancement of emission of carriers, and their relative contribution is determined by the charge state of the defect and by the electric-field strength. At high-electric field strengths carrier emission is dominated by tunneling independently of the charge state of the impurity. For neutral impurities, where Poole-Frenkel lowering of the emission barrier does not occur, the phonon assisted tunneling model describes well the experimental data also in the low-field region. For charged impurities the transition from phonon assisted tunneling at high fields to Poole-Frenkel effect at low fields can be traced back. It is suggested that the Poole-Frenkel and tunneling models can be distinguished by plotting logarithm of the emission rate against the square root or against the square of the electric field, respectively. This analysis enables one to unambiguously determine the charge state of a deep-level defect. C1 Univ Regensburg, Inst Expt & Angew Phys, D-93040 Regensburg, Germany. Russian Acad Sci, AF Ioffe Phys Tech Inst, St Petersburg 194021, Russia. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Ganichev, SD (reprint author), Univ Regensburg, Inst Expt & Angew Phys, Univ Str 31, D-93040 Regensburg, Germany. NR 24 TC 126 Z9 127 U1 4 U2 30 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 APR 15 PY 2000 VL 61 IS 15 BP 10361 EP 10365 DI 10.1103/PhysRevB.61.10361 PG 5 WC Physics, Condensed Matter SC Physics GA 306PZ UT WOS:000086606200084 ER PT J AU Siegal, MP Tallant, DR Martinez-Miranda, LJ Barbour, JC Simpson, RL Overmyer, DL AF Siegal, MP Tallant, DR Martinez-Miranda, LJ Barbour, JC Simpson, RL Overmyer, DL TI Nanostructural characterization of amorphous diamondlike carbon films SO PHYSICAL REVIEW B LA English DT Article ID PULSED-LASER DEPOSITION; X-RAY REFLECTIVITY; THIN-FILMS; ELECTRONIC-PROPERTIES; RAMAN-SPECTROSCOPY; THERMAL-STABILITY; FIELD-EMISSION; ENERGETICS; GROWTH; APPROXIMATION AB Nanostructural characterization of amorphous diamondlike carl,on (a-C) films grown on silicon using pulsed-laser deposition (PLD) is correlated to both growth energetics and film thickness. Raman spectroscopy and x-ray reflectivity probe both the topological nature of three and four-fold coordinated carbon atom bonding and the topographical clustering of their distributions within a given film. In general, increasing the energetics of PLD growth results in films becoming more "diamondlike," i.e., increasing mass density and decreasing optical absorbance. However, these same properties decrease appreciably with thickness. The topology of carbon atom bonding is different for material near the substrate interface compared to material within the bulk portion of an a-C film. A simple model balancing the energy of residual stress and the free energies of resulting carbon topologies is proposed to provide an explanation of the evolution of topographical bonding clusters in a growing a-C film. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. RP Siegal, MP (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 54 TC 67 Z9 70 U1 4 U2 10 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 2000 VL 61 IS 15 BP 10451 EP 10462 DI 10.1103/PhysRevB.61.10451 PG 12 WC Physics, Condensed Matter SC Physics GA 306PZ UT WOS:000086606200095 ER PT J AU Uspenskii, YA Harmon, BN AF Uspenskii, YA Harmon, BN TI Large selective magneto-optic response from magnetic semiconducting layered structures SO PHYSICAL REVIEW B LA English DT Article AB Magneto-optic (MO) spectra are considered for layered structures consisting of a magnetic semiconductor and a metal and having a resonant state. It is found that scattering on the resonant state results in a large MO response when the difference in resonant frequencies for left and right circular waves is large enough. The response is very selective for light waves of a certain helicity, and selection is reversed with magnetization reversal. Numerical calculations carried out for the Ag/EuS/Ag structure as well as analytical estimations show that a large selective MO response should be attainable experimentally. C1 Iowa State Univ, Ames Lab, Ames, IA 50010 USA. PN Lebedev Phys Inst, Moscow 117924, Russia. RP Uspenskii, YA (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50010 USA. EM uspenski@lpi.ac.ru RI Uspenskii, Yurii/L-6205-2015 NR 8 TC 11 Z9 11 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 APR 15 PY 2000 VL 61 IS 16 BP 10571 EP 10574 PG 4 WC Physics, Condensed Matter SC Physics GA 309EP UT WOS:000086755600009 ER PT J AU Budde, K Abram, E Yeh, V Tringides, MC AF Budde, K Abram, E Yeh, V Tringides, MC TI Uniform, self-organized, seven-step height Pb/Si(111)-(7X7) islands at low temperatures SO PHYSICAL REVIEW B LA English DT Article ID ENERGY ELECTRON-DIFFRACTION; GROWTH; PB; SI(111); AG AB An unusual growth mode has been observed during low temperature growth at T=185 It in the system Pb/Si(lll)-(7 x 7) with the formation of uniform seven-step, steep-edged, flat-top islands up to coverages theta=7.5 ML. The evidence is based on the spot profile analysis-low-energy electron diffraction diffracted intensity distribution as a function of k(parallel to), k(z) the parallel and normal components of the momentum transfer which show sevenfold oscillations over the range in k(z) where single step oscillations are expected. The formation of these highly uniform, self-organized structures implies that unconventional kinetic mechanisms operate at these low temperatures. C1 Iowa State Univ Sci & Technol, Dept Phys, Ames Lab, US DOE, Ames, IA 50011 USA. RP Tringides, MC (reprint author), Iowa State Univ Sci & Technol, Dept Phys, Ames Lab, US DOE, Ames, IA 50011 USA. EM tringides@ameslab.gov NR 14 TC 148 Z9 149 U1 2 U2 14 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 2000 VL 61 IS 16 BP 10602 EP 10605 PG 4 WC Physics, Condensed Matter SC Physics GA 309EP UT WOS:000086755600017 ER PT J AU Bockrath, M Hone, J Zettl, A McEuen, PL Rinzler, AG Smalley, RE AF Bockrath, M Hone, J Zettl, A McEuen, PL Rinzler, AG Smalley, RE TI Chemical doping of individual semiconducting carbon-nanotube ropes SO PHYSICAL REVIEW B LA English DT Article ID SINGLE-WALL; TRANSPORT-PROPERTIES; BUNDLES AB We report the effects of potassium doping on the conductance of individual semiconducting single-walled carbon nanotube ropes. We are able to control the level of doping by reversibly intercalating and de-intercalating potassium. Potassium doping changes the carriers in the ropes from holes to electrons. Typical values for the carrier density are found to be similar to 100-1000 electrons/mu m. The effective mobility for the electrons is mu(eff)similar to 20-60 cm(2) V-1 s(-1), a value similar to that reported for the hole effective mobility in nanotubes [R. Martel et al., Appl. Phys. Lett. 73, 2447 (1998)]. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. Rice Univ, Rice Quantum Inst, Ctr Nanoscale Sci & Technol, Houston, TX 77251 USA. Rice Univ, Dept Chem & Phys, Houston, TX 77251 USA. RP Bockrath, M (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Hone, James/E-1879-2011; Zettl, Alex/O-4925-2016 OI Hone, James/0000-0002-8084-3301; Zettl, Alex/0000-0001-6330-136X NR 10 TC 133 Z9 135 U1 0 U2 11 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 2000 VL 61 IS 16 BP 10606 EP 10608 PG 3 WC Physics, Condensed Matter SC Physics GA 309EP UT WOS:000086755600018 ER PT J AU Woods, LM Mahan, GD AF Woods, LM Mahan, GD TI Electron-phonon effects in graphene and armchair (10,10) single-wall carbon nanotubes SO PHYSICAL REVIEW B LA English DT Article ID TUBULES; ROPES; CONDUCTIVITY; TRANSPORT AB The electron-phonon interaction in low-dimensional tight-binding systems is discussed. A sheet of graphite, which is two-dimensional, and an armchair single-wall carbon nanotube (SWNT), which is quasi-one-dimensional, are taken as examples. For the modulated hopping the matrix elements for both systems are derived in the context of a two parameter model. for the phonon vibrational spectrum. It is found that they (for both structures) display a deformation type of potential, and are reduced by a factor of (I-R), where R depends on the phonon parameters. It is also shown that the ordinary electron-phonon coupling displays a deformation type of approximation for both systems. Next, a different type of interaction is considered-the phonon modulated electron-electron interaction. It gives two contributions-random phase approximation with one phonon Line and exchange interaction with one phonon line. We find that for the two-dimensional (2D) graphene and for the quasi-ID (10,10) SWNT, the modulated hopping and exchange coupling govern the electron transport at room temperatures. C1 Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Woods, LM (reprint author), Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. NR 22 TC 80 Z9 81 U1 4 U2 23 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 APR 15 PY 2000 VL 61 IS 16 BP 10651 EP 10663 DI 10.1103/PhysRevB.61.10651 PG 13 WC Physics, Condensed Matter SC Physics GA 309EP UT WOS:000086755600024 ER PT J AU List, EJW Partee, J Shinar, J Scherf, U Mullen, K Zojer, E Petritsch, K Leising, G Graupner, W AF List, EJW Partee, J Shinar, J Scherf, U Mullen, K Zojer, E Petritsch, K Leising, G Graupner, W TI Localized triplet excitations and the effect of photo-oxidation in ladder-type poly(p-phenylene) and oligo(p-phenylene) SO PHYSICAL REVIEW B LA English DT Article ID DETECTED MAGNETIC-RESONANCE; LIGHT-EMITTING-DIODES; CONJUGATED POLYMER; LOWEST SINGLET; STIMULATED-EMISSION; CHARGED EXCITATIONS; EXCITED-STATES; CHAIN-LENGTH; FILMS; POLY(PARA-PHENYLENE) AB The photophysics of methyl-bridged poly(para-phenylene)-type ladder polymer (m-LPPP) and oligomer films and solutions is described and discussed. The spin sensitive properties, such as the formation and properties of polaron pairs and triplet excitons (TE's) were studied using X-band photoluminescence (PL) detected magnetic resonance (PLDMR). The PLDMR results and quantum chemical calculations show unambiguously that the TE wave-function extent is much smaller than that of the singlet exciton (SE). The weaker vibronic structure of the triplet photoinduced absorption (PA) band of m-LPPP relative to the singlet absorption is assigned to the small energy difference between the geometry of the lowest lying and excited triplet states. This is an additional indication of the strong localization of the triplet wave-function as compared to that of the SE. Finally, the influence of photo-oxidation on the PLDMR and PA is analyzed and discussed in relation to the photoconductivity of the materials. C1 Graz Tech Univ, Inst Festkorperphys, A-8010 Graz, Austria. Iowa State Univ, Ames Lab, US Dept Energy, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. Max Planck Inst Polymerforsch, Mainz, Germany. Virginia Tech, Dept Phys, Blacksburg, VA 24060 USA. RP List, EJW (reprint author), Graz Tech Univ, Inst Festkorperphys, Petersgasse 16, A-8010 Graz, Austria. RI Zojer, Egbert/B-3265-2010; Scherf, Ullrich/G-1552-2012; List-Kratochvil, Emil/M-5312-2013 OI Zojer, Egbert/0000-0002-6502-1721; NR 51 TC 62 Z9 62 U1 3 U2 18 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 APR 15 PY 2000 VL 61 IS 16 BP 10807 EP 10814 DI 10.1103/PhysRevB.61.10807 PG 8 WC Physics, Condensed Matter SC Physics GA 309EP UT WOS:000086755600042 ER PT J AU Gaillard, MK AF Gaillard, MK TI One-loop regularization of supergravity: The dilaton and the superfield formulation SO PHYSICAL REVIEW D LA English DT Article ID PAULI-VILLARS REGULARIZATION; YANG-MILLS MATTER; STRING EFFECTIVE THEORIES; ANOMALY CANCELLATION; GAUGE COUPLINGS; CHIRAL MATTER; FIELDS AB The on-shell regularization of the one-loop divergences of supergravity theories is generalized to include a dilaton of the type occurring in effective field theories derived from superstring theory, and the superfield structure of the one-loop corrections is given. Field theory anomalies and quantum contributions to soft supersymmetry breaking are discussed. The latter are sensitive to the precise choice of couplings that generate Pauli-Villars masses, which in turn reflect the details of the underlying theory above the scale of the effective cutoff. With a view to the implementation the Green-Schwarz and other mechanisms for canceling field theory anomalies under a U(1) gauge transformation and under the T-duality group of modular transformations, we show that the Kahler potential renormalization for the untwisted sector of orbifold compactification can be made invariant under these groups. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Phys, Berkeley, CA 94720 USA. NR 28 TC 16 Z9 16 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD APR 15 PY 2000 VL 61 IS 8 AR 084028 DI 10.1103/PhysRevD.61.084028 PG 25 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 305RM UT WOS:000086554100055 ER PT J AU Anderson, CO Niesen, JFM Blanch, HW Prausnitz, JM AF Anderson, CO Niesen, JFM Blanch, HW Prausnitz, JM TI Interactions of proteins in aqueous electrolyte solutions from fluorescence anisotropy and circular-dichroism measurements SO BIOPHYSICAL CHEMISTRY LA English DT Article DE protein-protein interactions; specific interactions; potentials of mean force; fluorescence polarization anisotropy; amyloid fibrillogenesis; circular-dichroism ID AMYLOID-BETA-PROTEIN; LYSOZYME; PEPTIDE; FIBRILLOGENESIS; AGGREGATION; SHEET AB Understanding aqueous protein-protein interactions is crucial for the development of a molecular-thermodynamic model for salt-induced protein precipitation. In addition, protein interactions are important in many disease states, including cataract formation and a-amyloid diseases. Fluorescence anisotropy provides a means to measure intermolecular interactions. In this work, monomer-dimer equilibrium of the peptide T4 LYS(11-36) was studied by fluorescence anisotropy over the pH range 4-7 and the NaCl concentration range 0.0-1.0 M, in a 25 mM sodium phosphate buffer. This 26 amino-acid peptide is derived from the P-sheet region of the T4 lysozyme molecule and has the potential to form amyloid fibrils. The association constant for dimerization increases with rising pH and ionic strength. The potential of mean force for peptide-peptide interactions was calculated from these association constants. Circular-dichroism measurements show that the peptide becomes more structured as the pH rises, possibly contributing to increased association. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Blanch, HW (reprint author), Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. NR 26 TC 9 Z9 9 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-4622 J9 BIOPHYS CHEM JI Biophys. Chem. PD APR 14 PY 2000 VL 84 IS 2 BP 177 EP 188 DI 10.1016/S0301-4622(00)00115-0 PG 12 WC Biochemistry & Molecular Biology; Biophysics; Chemistry, Physical SC Biochemistry & Molecular Biology; Biophysics; Chemistry GA 302DH UT WOS:000086349800008 PM 10796032 ER PT J AU Le Page, F Kwoh, EE Avrutskaya, A Gentil, A Leadon, SA Sarasin, A Cooper, PK AF Le Page, F Kwoh, EE Avrutskaya, A Gentil, A Leadon, SA Sarasin, A Cooper, PK TI Transcription-coupled repair of 8-oxoGuanine: Requirement for XPG, TFIIH, and CSB and implications for Cockayne syndrome (Retracted Article. See vol 123, pg 711, 2005) SO CELL LA English DT Article; Retracted Publication ID NUCLEOTIDE EXCISION-REPAIR; RNA-POLYMERASE-II; OXIDATIVE DNA-DAMAGE; GROUP-B CELLS; XERODERMA-PIGMENTOSUM; ESCHERICHIA-COLI; MAMMALIAN-CELLS; IN-VITRO; SACCHAROMYCES-CEREVISIAE; HUMAN HOMOLOG AB Analysis of transcription-coupled repair (TCR) of oxidative lesions here reveals strand-specific removal of 8-oxo-guanine (8-oxoG) and thymine glycol both in normal human cells and xeroderma pigmentosum (XP) cells defective in nucleotide excision repair. In contrast, Cockayne syndrome (CS) cells including CS-B, XP-B/CS, XP-D/CS, and XP-G/CS not only lack TCR but cannot remove 8-oxoG in a transcribed sequence, despite its proficient repair when not transcribed. The XP-G/CS defect uniquely slows lesion removal in nontranscribed sequences. Defective TCR leads to a mutation frequency at 8-oxoG of 30%-40% compared to the normal 1%-4%. Surprisingly, unrepaired 8-oxoG blocks transcription by RNA polymerase II. These data imply that TCR is required for polymerase release to allow repair and that CS results from defects in TCR of oxidative lesions. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. CNRS, UPR42, Mol Genet Lab, F-94801 Villejuif, France. Univ N Carolina, Sch Med, Dept Radiat Oncol, Chapel Hill, NC 27599 USA. RP Sarasin, A (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. EM sarasin@infobiogen.fr; pkcooper@lbl.gov FU NCI NIH HHS [CA40453, CA63503] NR 69 TC 271 Z9 272 U1 7 U2 11 PU CELL PRESS PI CAMBRIDGE PA 600 TECHNOLOGY SQUARE, 5TH FLOOR, CAMBRIDGE, MA 02139 USA SN 0092-8674 J9 CELL JI Cell PD APR 14 PY 2000 VL 101 IS 2 BP 159 EP 171 DI 10.1016/S0092-8674(00)80827-2 PG 13 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 305DP UT WOS:000086524400003 PM 10786832 ER PT J AU Kent, MS AF Kent, MS TI A quantitative study of tethered chains in various solution conditions using Langmuir diblock copolymer monolayers SO MACROMOLECULAR RAPID COMMUNICATIONS LA English DT Review ID SELF-CONSISTENT-FIELD; GRAFTED POLYMER BRUSHES; ADSORBED BLOCK COPOLYMERS; ATOMIC-FORCE MICROSCOPY; NEUTRON REFLECTIVITY; GOOD SOLVENT; POOR SOLVENT; ASSEMBLED MONOLAYERS; PHASE-TRANSITION; MOLECULAR-WEIGHT AB This article summarizes our investigations of tethered chain systems using Langmuir monolayers of poly(dimethylsiloxane)-polystyrene (PDMS-PS) diblock copolymers on organic liquids. In this system, the PDMS block absorbs strongly to the air surface while the PS block dangles into the subphase liquid. The air surface can be made either repulsive or attractive for the tethered PS chain segments by choosing a subphase liquid which has a surface tension less than or greater than that of PS, respectively. The segment profile of the PS block is determined by neutron reflection as a function of the surface density, the molecular weights of the PS and PDMS blocks, and the solution conditions. We cover the range of reduced surface density (Sigma) characteristic of the large body of data in the literature for systems of chains tethered onto solid surfaces from dilute solution in good or theta solvent conditions (Sigma < 12). We emphasize quantitative comparisons with analytical profile forms and scaling predictions. We find that the strong-stretching limit assumed in analytical self-consistent field calculations (SCF) and scaling theories is not valid over this Sigma range. On the other hand, over a large portion of this range (Sigma less than or equal to 5) tethered chain profiles are well described by a renormalization group theory for weakly interacting or noninteracting chains. Simultaneous with the study of the profile form, the free energy of the tethered chains is examined through the surface tension. A strong increase in the surface pressure is observed with increasing surface density which determines the maximum surface density which can be achieved. This effect is attributed to a combination of higher order osmotic interactions and configurational constraints. This effect may explain several outstanding discrepancies regarding the adsorption of end-functionalized chains and diblock copolymers onto solid surfaces. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Kent, MS (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 145 TC 74 Z9 74 U1 2 U2 19 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 1022-1336 J9 MACROMOL RAPID COMM JI Macromol. Rapid Commun. PD APR 14 PY 2000 VL 21 IS 6 BP 243 EP 270 DI 10.1002/(SICI)1521-3927(20000301)21:6<243::AID-MARC243>3.0.CO;2-R PG 28 WC Polymer Science SC Polymer Science GA 306RD UT WOS:000086609100001 ER PT J AU Yang, P Turman, BN Glass, SJ Halbleib, JA Voth, TE Gerstle, FP Mckenzie, B Clifford, JR AF Yang, P Turman, BN Glass, SJ Halbleib, JA Voth, TE Gerstle, FP Mckenzie, B Clifford, JR TI Braze microstructure evolution and mechanical properties of electron beam joined ceramics SO MATERIALS CHEMISTRY AND PHYSICS LA English DT Article DE scanning electron microscopy; ceramics; energy dispersive x-ray spectrometer ID ALUMINA AB A study was conducted to demonstrate the feasibility of ceramic joining using a high-energy (10 MeV) electron beam. Special emphasis was paid to define the beam operating parameters necessary to produce strong, hermetic seals. Electron beams with energies in this range penetrate through a significant thickness of ceramic (>1 cm), depositing their energy deep within a part. Thus, this process provides a special capability for producing joints at buried interfaces. Scanning electron microscopy (SEM) and an energy dispersive X-ray spectrometer (EDS) were used to evaluate the degree of reaction between buried braze metals and ceramic substrates. The mechanical integrity of cylinder joints was evaluated using a standard tensile strength test. The hermeticity of the joint was also tested. Specimens joined by electron beams were compared to specimens fabricated by conventional oven brazing. Prior to strength testing or sectioning for microstructural examination, some samples were examined non-destructively using ultrasound to evaluate the degree of bonding in the joint area. The microstructures of these ultrasonically identified 'strongly' and 'weakly' bonded regions were studied and compared. The sequence of phase formation at the ceramic-braze interface is explained in terms of changes in the chemical activity of titanium and microstructure in the solidified brazes. Mechanical strength and microstructural evolution appear to correlate well with the reaction kinetics involved at the ceramic-braze interface. (C)2000 Elsevier Science S.A. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Titan Adv Technol Grp, Albuquerque, NM USA. RP Yang, P (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 16 TC 8 Z9 15 U1 1 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0254-0584 J9 MATER CHEM PHYS JI Mater. Chem. Phys. PD APR 14 PY 2000 VL 64 IS 2 BP 137 EP 146 DI 10.1016/S0254-0584(99)00248-5 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA 294TZ UT WOS:000085927600006 ER PT J AU Hong, SI Hill, MA AF Hong, SI Hill, MA TI Mechanical properties of Cu-Nb microcomposites fabricated by the bundling and drawing process SO SCRIPTA MATERIALIA LA English DT Article DE mechanical properties; microstructure; recrystallization and recovery ID IN-SITU COMPOSITES; YIELD STRENGTH; MICROSTRUCTURE; POWDERS; STRAINS; ALLOYS C1 Chungnam Natl Univ, Dept Met Engn, Taejon 305764, South Korea. Chungnam Natl Univ, RASOM, Taejon 305764, South Korea. Univ Calif Los Alamos Natl Lab, Div Mat Sci, Los Alamos, NM 87545 USA. RP Hong, SI (reprint author), Chungnam Natl Univ, Dept Met Engn, Taedok Sci Town, Taejon 305764, South Korea. NR 18 TC 18 Z9 29 U1 1 U2 2 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 APR 14 PY 2000 VL 42 IS 8 BP 737 EP 742 DI 10.1016/S1359-6462(99)00423-6 PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 308DG UT WOS:000086694800001 ER PT J AU Martinez-Fernandez, J Dominguez-Rodriguez, A Routbort, JL Goretta, KC AF Martinez-Fernandez, J Dominguez-Rodriguez, A Routbort, JL Goretta, KC TI Creep of polycrystalline (Bi,Pb)(2)Sr2Ca2Cu3Ox SO SCRIPTA MATERIALIA LA English DT Article DE creep; constitutive equations; superconductor; microstructure ID CU-O SUPERCONDUCTORS; SINGLE-CRYSTALS; DEFORMATION; DIFFUSION; CERAMICS; BEHAVIOR; TAPES; DENSE; PHASE; (BI C1 Univ Seville, Dept Mat Condensada, Seville 41080, Spain. Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. RP Martinez-Fernandez, J (reprint author), Univ Seville, Dept Mat Condensada, Seville 41080, Spain. RI MARTINEZ FERNANDEZ, JULIAN/K-1826-2012; OI MARTINEZ FERNANDEZ, JULIAN/0000-0002-1199-6638; Dominguez-Rodriguez, Arturo/0000-0003-1598-5669 NR 24 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 1359-6462 J9 SCRIPTA MATER JI Scr. Mater. PD APR 14 PY 2000 VL 42 IS 8 BP 743 EP 747 DI 10.1016/S1359-6462(99)00424-8 PG 5 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 308DG UT WOS:000086694800002 ER PT J AU Gilbert, CJ Bloyer, DR Barsoum, MW El-Raghy, T Tomsia, AP Ritchie, RO AF Gilbert, CJ Bloyer, DR Barsoum, MW El-Raghy, T Tomsia, AP Ritchie, RO TI Fatigue-crack growth and fracture properties of coarse and fine-grained Ti3SiC2 SO SCRIPTA MATERIALIA LA English DT Article DE ceramics; Ti3SiC2; mechanical properties; fracture; fatigue ID CYCLIC FATIGUE; HARDNESS INDENTATIONS; CERAMICS; ALUMINA; MECHANISMS C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. Drexel Univ, Dept Mat Engn, Philadelphia, PA USA. RP Gilbert, CJ (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Ritchie, Robert/A-8066-2008 OI Ritchie, Robert/0000-0002-0501-6998 NR 20 TC 102 Z9 106 U1 4 U2 25 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 APR 14 PY 2000 VL 42 IS 8 BP 761 EP 767 DI 10.1016/S1359-6462(99)00427-3 PG 7 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 308DG UT WOS:000086694800005 ER PT J AU Hsueh, CH Fuller, ER AF Hsueh, CH Fuller, ER TI Analytical modeling of oxide thickness effects on residual stresses in thermal barrier coatings SO SCRIPTA MATERIALIA LA English DT Article DE modeling; thermal barrier coating; thermal expansion; stress ID OXIDATION-INDUCED STRESSES; SCALES; FILMS C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Hsueh, CH (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Hsueh, Chun-Hway/G-1345-2011 NR 9 TC 48 Z9 60 U1 2 U2 23 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 APR 14 PY 2000 VL 42 IS 8 BP 781 EP 787 DI 10.1016/S1359-6462(99)00430-3 PG 7 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 308DG UT WOS:000086694800008 ER PT J AU Yost, FG AF Yost, FG TI Kinetics of reactive wetting SO SCRIPTA MATERIALIA LA English DT Article DE reactive wetting; theory and modeling of diffusion; heterogenous phase transformations; structural ceramics; intermetallic compounds ID DROPS C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Yost, FG (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 15 TC 14 Z9 18 U1 0 U2 6 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 APR 14 PY 2000 VL 42 IS 8 BP 801 EP 806 DI 10.1016/S1359-6462(00)00298-0 PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 308DG UT WOS:000086694800011 ER PT J AU Miller, JH Minard, K Wind, RA Orner, GA Sasser, LB Bull, RJ AF Miller, JH Minard, K Wind, RA Orner, GA Sasser, LB Bull, RJ TI In vivo MRI measurements of tumor growth induced by dichloroacetate: implications for mode of action SO TOXICOLOGY LA English DT Article DE dichloroacetate; liver cancer; mice; MRI; tumor growth; tumor promotion ID DISINFECTION BY-PRODUCTS; MALE B6C3F1 MOUSE; TRICHLOROACETIC-ACID; CHLORAL HYDRATE; DRINKING-WATER; IN-VIVO; LIVER; CARCINOGENICITY; APOPTOSIS; MICE AB Dichloroacetate (DCA) is an important by-product of the chlorination of drinking water that produces liver cancer in rodents. Assessment of the risk that results from concentrations that occur in drinking water will be dependent upon the mode of action held responsible for these tumors. A study by Stauber and Bull [Stauber, A.J. and Bull, R.J (1997) Differences in phenotype and cell replicative behavior of hepatic tumors inducted by dichloroacetate (DCA) and trichloroacetate (TCA). Toxicol. Appl. Pharmacol. 144, 235-246] in mice treated with DCA demonstrated a lesion distribution that was skewed towards many small, altered foci of cells that are assumed to be precursor lesions [EPA, (1996). U.S. Environmental Protection Agency: Proposed Guidelines for carcinogen risk assessment: notice. Fed. Peg. 61, pp. 17 960-10 811]. The present study was designed to determine the extent to which the tumorigenic effects of DCA could be explained by its effect on tumor growth rates (i.e. tumor promoting activity). In vivo magnetic resonance imaging (MRI) allowed accurate determination of growth rates of individual lesions in mice that had been treated with DCA in drinking water at 2 g/l. Out Of thirty treated mice, ten were found to have hepatic tumors detectable by MRI at 48 weeks of treatment. These tumor-bearing animals were assigned to two groups matched on the size of lesions observed by in vivo MR1. Treatment with DCA continued in one group of five mice and was stopped in the other. For both groups, tumor growth rates were determined by measuring changes in size of all lesions greater than 1 mm(3) in volume during a 14-day period. Removal of DCA treatment resulted in growth rates that could not be distinguished from zero across all lesion sizes represented in the sample. These data are in agreement with previous observations of DCAs effects on replication rates within tumors (Stauber and Bull, (1997)). Tumor growth rates observed in animals maintained on treatment decreased with lesion volume in a manner that is consistent with a stochastic Gompertz birth-death process proposed by Tan [Tan, W.Y. (1986) A stochastic Gompertz birth-death process. Stat. Prob. Lett. 4, 25-28]. Parameters of this model obtained by fitting measured growth rates were used to predict the lesion-size distribution expected after one year of DCA treatment. The shape of the predicted lesion-size distribution was similar to that observed by Stauber and Bull (Stauber and Bull, (1997)) in mice sacrificed after 40 weeks of DCA treatment. We conclude that the effects of DCA on the division and/or death rates of spontaneously initiated cells can account for the predominance of small lesions in DCA-treated animals. (C) 2000 Published by Elsevier Science Ireland Ltd. All rights reserved. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Bull, RJ (reprint author), Pacific NW Natl Lab, POB 999-P7-56, Richland, WA 99352 USA. EM dick.bull@pnl.gov RI Orner, Gayle/F-6876-2013 OI Orner, Gayle/0000-0002-4812-5297 NR 31 TC 19 Z9 20 U1 1 U2 3 PU ELSEVIER IRELAND LTD PI CLARE PA ELSEVIER HOUSE, BROOKVALE PLAZA, EAST PARK SHANNON, CO, CLARE, 00000, IRELAND SN 0300-483X J9 TOXICOLOGY JI Toxicology PD APR 14 PY 2000 VL 145 IS 2-3 BP 115 EP 125 DI 10.1016/S0300-483X(00)00148-7 PG 11 WC Pharmacology & Pharmacy; Toxicology SC Pharmacology & Pharmacy; Toxicology GA 311PE UT WOS:000086892400003 PM 10771136 ER PT J AU Li, WK Lau, KC Ng, CY Baumgartel, H Weitzel, KM AF Li, WK Lau, KC Ng, CY Baumgartel, H Weitzel, KM TI Gaussian-2 and Gaussian-3 study of the energetics and structures of Cl2On and Cl2On+, n=1-7 SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID G2 AB-INITIO; GAS-PHASE; VIBRATIONAL FREQUENCIES; ROTATIONAL SPECTRUM; ELECTRON-AFFINITIES; DICHLORINE HEXOXIDE; MOLECULAR-STRUCTURE; CHLORINE DIOXIDE; OZONE DEPLETION; ISOMERIC CH3O2 AB The structures and energetics of the dichlorine oxides, Cl2On, n = 1-7, and their cations have been investigated theoretically at the Gaussian-2 (G2) and the Gaussian-3 (G3) levels of theory. The G2 and G3 heats of formation obtained for both neutral and cationic species allow the interpretation of assigned appearance energies and ionization energies reported in a recent photoionization mass spectrometric study (Ruhl et al. int. J. Mass Spectrom. 1999, 185, 545) on these chlorine oxides. The calculations predict that Cl2O6+ dissociates spontaneously to ClO2+ and ClO4, in agreement with the nonobservation of Cl2O6+ in the experimental study by Ruhl et al. For systems with n less than or equal to 4, the calculated and experimental thermochemical properties (such as heats of formation and ionization energies) are in good to excellent agreement with each other. However, this agreement deteriorates as the size of the molecular system increases or as n exceeds 4. Thus it appears that the G3 method may also suffer from "an unfavorable accumulation of component small errors," as has been found for the G2 method and its variants. C1 Chinese Univ Hong Kong, Dept Chem, Shatin, Hong Kong, Peoples R China. US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Free Univ Berlin, Inst Phys & Theoret Chem, D-14195 Berlin, Germany. RP Li, WK (reprint author), Chinese Univ Hong Kong, Dept Chem, Shatin, Hong Kong, Peoples R China. OI LAU, Kai Chung /0000-0003-2125-6841 NR 60 TC 15 Z9 16 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 APR 13 PY 2000 VL 104 IS 14 BP 3197 EP 3203 DI 10.1021/jp993398y PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 306LG UT WOS:000086597700014 ER PT J AU Baldell, SJ Bernasek, SL Stair, PC Zaera, F AF Baldell, SJ Bernasek, SL Stair, PC Zaera, F TI Gabor A. Somorjai SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Biographical-Item C1 Lawrence Berkeley Natl Lab, Berkeley, CA USA. Princeton Univ, Princeton, NJ 08544 USA. Northwestern Univ, Evanston, IL 60208 USA. Univ Calif Riverside, Riverside, CA 92521 USA. RP Baldell, SJ (reprint author), Lawrence Berkeley Natl Lab, Berkeley, CA USA. RI Zaera, Francisco/J-8720-2013 NR 1 TC 0 Z9 0 U1 0 U2 1 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 APR 13 PY 2000 VL 104 IS 14 BP 2937 EP 2968 PG 32 WC Chemistry, Physical SC Chemistry GA 306MD UT WOS:000086599700001 ER PT J AU Somorjai, GA AF Somorjai, GA TI The development of molecular surface science and the surface science of catalysis: Berkeley contribution SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Review ID ENERGY-ELECTRON-DIFFRACTION; SUM-FREQUENCY GENERATION; SINGLE-CRYSTAL SURFACES; SCANNING-TUNNELING-MICROSCOPY; INDEX PLATINUM SURFACES; ZIEGLER-NATTA CATALYST; AUTOMATED TENSOR LEED; CHLORIDE THIN-FILMS; STRUCTURE SENSITIVITY; CARBON-MONOXIDE AB Since the early 1960s, surface science has uncovered the atomic and electronic structures of surfaces and the nature of chemical bonding of adsorbed monolayers of atoms and molecules. Surface instrumentation was developed to carry out these studies as well as to monitor surface reactions, stoichiometric and catalytic. Metal, oxide, molecular crystal, and polymer surfaces have been investigated on the molecular scale. Studies in vacuum and at low pressures that used electrons, ions, and atoms as surface probes have been extended in recent years to high pressures and studies of solid-liquid interfaces by using photon scattering techniques and surface probe microscopes. My laboratory in Berkeley has participated in the development of molecular surface science and heterogeneous catalysis during the past 35 years. The following is a personal review of our contributions to the field. C1 Univ Calif Berkeley, Dept Chem, Div Mat Sci, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Somorjai, GA (reprint author), Univ Calif Berkeley, Dept Chem, Div Mat Sci, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. NR 141 TC 31 Z9 31 U1 0 U2 27 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1520-6106 J9 J PHYS CHEM B JI J. Phys. Chem. B PD APR 13 PY 2000 VL 104 IS 14 BP 2969 EP 2979 DI 10.1021/jp993515p PG 11 WC Chemistry, Physical SC Chemistry GA 306MD UT WOS:000086599700002 ER PT J AU Radulovic, PV Feigerle, CS Overbury, SH AF Radulovic, PV Feigerle, CS Overbury, SH TI Structure of Pt overlayers on ZnO(0001) and ZnO(000(1)over-bar) surfaces SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID ION-SCATTERING; ZINC-OXIDE; CHEMISORPTIVE PROPERTIES; ELECTRONIC-PROPERTIES; METAL-FILMS; CU FILMS; PARTICLES; AES; ZNO AB The growth of Pt films on the Zn- and O-terminated polar surfaces of ZnO has been studied. Clean surfaces, prepared by sputtering and annealing, were dosed with Pt by vapor deposition. Properties of the film were examined by low-energy alkali ion scattering and low-energy electron diffraction. It is confirmed that, near room temperature, Pt grows on both surfaces as a single hexagonal layer which aligns with the substrate low index directions. The alignment is better for the Zn-terminated than for the O-terminated surface. A Pt monolayer grows on the Zn-terminated surface until the ZnO surface is essentially covered with no evidence of a second Pt layer. Upon annealing above 675 K, Pt agglomerates into mostly bilayer islands, but maintains or improves its alignment with the substrate. Features associated with scattering from bi- or multilayer Pt indicate that the Pt forms oriented (Ill)rafts. A coincidence LEED pattern indicates that the Pt lattice may be expanded by 0.5% to form a 6:7 coincidence overlayer with the ZnO lattice. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. RP Overbury, SH (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Overbury, Steven/C-5108-2016 OI Overbury, Steven/0000-0002-5137-3961 NR 25 TC 10 Z9 10 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD APR 13 PY 2000 VL 104 IS 14 BP 3028 EP 3034 DI 10.1021/jp993325e PG 7 WC Chemistry, Physical SC Chemistry GA 306MD UT WOS:000086599700008 ER PT J AU Climent, V Markovic, NM Ross, PN AF Climent, V Markovic, NM Ross, PN TI Kinetics of oxygen reduction on an epitaxial film of palladium on Pt(111) SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID SINGLE-CRYSTAL SURFACES; ACID-SOLUTIONS; PLATINUM; ADSORPTION; VOLTAMMETRY; ELECTRODES; INTERFACE; BEHAVIOR; HYDROGEN; VACUUM AB The kinetics of the oxygen reduction reaction on epitaxial thin films of Pd on Pt(111) was studied using the rotating ring-disk electrode technique. The results for the pseudomorphic monolayer of Pd are compared to those of the unmodified Pt(111) surface, both surfaces having nominally identical 2D structures. Tn an electrolyte containing a nonabsorbing anion, 0.5 M HClO4, the pseudomorphic layer of Pd has a somewhat lower (ca. factor of 2) activity than Pt(111). In an electrolyte containing an anion which is strongly adsorbing on Pt(111), 0.5 M H2SO4, the inhibition due to anion absorption is even greater on the pseudomorphic monolayer of Pd than on the unmodified Pt(111s) surface. This additional inhibition is attributed to the difference in the potential of zero charge (pzc) between the two surfaces, the Pt(111) having the more positive pzc. C1 Univ Calif Berkeley, Dept Mat Sci, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Alicante, Dept Chem, E-03080 Alicante, Spain. RP Ross, PN (reprint author), Univ Calif Berkeley, Dept Mat Sci, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RI Climent, Victor/F-6491-2011 OI Climent, Victor/0000-0002-2033-5284 NR 29 TC 78 Z9 79 U1 3 U2 28 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 APR 13 PY 2000 VL 104 IS 14 BP 3116 EP 3120 DI 10.1021/jp993480t PG 5 WC Chemistry, Physical SC Chemistry GA 306MD UT WOS:000086599700018 ER PT J AU Mugele, F Baldelli, S Somorjai, GA Salmeron, M AF Mugele, F Baldelli, S Somorjai, GA Salmeron, M TI Structure of confined films of chain alcohols SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID PHASE-TRANSITION; SOLVATION FORCES; 1-ALCOHOL MONOLAYERS; SURFACE FORCES; SUM-FREQUENCY; THIN-FILMS; LIQUID; WATER; CONTACT; ALKANES AB The structure of thin films of simple chain alcohols (1-octanol and 1-undecanol) confined between two atomically smooth mica surfaces has been investigated using a surface forces apparatus. Contact angle measurements and optical sum frequency generation were used for additional characterization. In both systems, the substrate-molecule interaction leads to a strongly bound first layer on each surface. Additional liquid organizes into highly compressible bilayers, which could be expelled by applying sufficiently high pressure. C1 Univ Calif Berkeley, Div Mat Sci, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Salmeron, M (reprint author), Univ Calif Berkeley, Div Mat Sci, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RI Mugele, Frieder/A-5225-2017 OI Mugele, Frieder/0000-0003-3824-3617 NR 30 TC 32 Z9 32 U1 1 U2 10 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 APR 13 PY 2000 VL 104 IS 14 BP 3140 EP 3144 DI 10.1021/jp9935236 PG 5 WC Chemistry, Physical SC Chemistry GA 306MD UT WOS:000086599700021 ER PT J AU Wei, X Hong, SC Lvovsky, AI Held, H Shen, YR AF Wei, X Hong, SC Lvovsky, AI Held, H Shen, YR TI Evaluation of surface vs bulk contributions in sum-frequency vibrational spectroscopy using reflection and transmission geometries SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID 2ND-HARMONIC GENERATION; INTERFACES; POLYMER AB An experiment was designed to measure sum-frequency generation (SFG) spectra in both reflection and transmission. The result from an octadecyltrichlorosilane monolayer on a substrate reveals that while the resonant spectra in the two geometries both originate from the surface monolayer, the bulk substrate has a significant contribution to the nonresonant background in the transmitted spectra. Study of a polyethylene film also shows that the bulk contribution to the SFG spectra is only significant for the transmission geometry, exhibiting a resonant mode not observable in the reflected spectra. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Shen, YR (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Lvovsky, Alexander/C-6830-2008 OI Lvovsky, Alexander/0000-0003-3165-6654 NR 16 TC 92 Z9 92 U1 1 U2 26 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1520-6106 J9 J PHYS CHEM B JI J. Phys. Chem. B PD APR 13 PY 2000 VL 104 IS 14 BP 3349 EP 3354 DI 10.1021/jp9933929 PG 6 WC Chemistry, Physical SC Chemistry GA 306MD UT WOS:000086599700045 ER PT J AU Quinn, H AF Quinn, H TI No conflict between SLAC and Japan's KEK SO NATURE LA English DT Letter C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Quinn, H (reprint author), Stanford Linear Accelerator Ctr, MS 81,POB 4349, Stanford, CA 94309 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD APR 13 PY 2000 VL 404 IS 6779 BP 701 EP 701 DI 10.1038/35008256 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 305DF UT WOS:000086523600019 ER PT J AU Mook, HA Dai, PC Dogan, F Hunt, RD AF Mook, HA Dai, PC Dogan, F Hunt, RD TI One-dimensional nature of the magnetic fluctuations in YBa2Cu3O6.6 SO NATURE LA English DT Article ID NEUTRON-SCATTERING; HUBBARD-MODEL; SUPERCONDUCTORS AB There is increasing evidence that inhomogeneous distributions of charge and spin-so-called 'striped phases'-play an important role in determining the properties of the high-temperature superconductors. For example, recent neutron-scattering measurements on the YBa2Cu3O7-x family of materials show both spin and charge fluctuations that are consistent with the striped-phase picture. But the fluctuations associated with a striped phase are expected to be one-dimensional, whereas the magnetic fluctuations observed to date appear to display two-dimensional symmetry. We show here that this apparent two-dimensionality results from measurements on twinned crystals, and that similar measurements on substantially detwinned crystals of YBa2Cu3O6.6 reveal the one-dimensional character of the magnetic fluctuations, thus greatly strengthening the striped-phase interpretation. Moreover, our results also suggest that superconductivity originates in charge stripes that extend along the b crystal axis, where the superfluid density is found to be substantially larger than for the a direction. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Washington, Dept Mat Sci & Engn, Seattle, WA 98195 USA. RP Mook, HA (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Dai, Pengcheng /C-9171-2012 OI Dai, Pengcheng /0000-0002-6088-3170 NR 24 TC 193 Z9 195 U1 0 U2 4 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD APR 13 PY 2000 VL 404 IS 6779 BP 729 EP 731 DI 10.1038/35008005 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 305DF UT WOS:000086523600041 ER PT J AU Egolf, DA Melnikov, IV Pesch, W Ecke, RE AF Egolf, DA Melnikov, IV Pesch, W Ecke, RE TI Mechanisms of extensive spatiotemporal chaos in Rayleigh-Bernard convection SO NATURE LA English DT Article ID SPIRAL-DEFECT CHAOS; BENARD CONVECTION; PRANDTL NUMBER; DYNAMICS; TRANSITION; ATTRACTORS; DIMENSION; FLUID AB Spatially extended dynamical systems exhibit complex behaviour in both space and time-spatiotemporal chaos(1,2). Analysis of dynamical quantities (such as fractal dimensions and Lyapunov exponents(3)) has provided insights into low-dimensional systems; but it has proven more difficult to understand spatiotemporal chaos in high-dimensional systems, despite abundant data describing its statistical properties(1,4,5). Initial attempts have been made to extend the dynamical approach to higher-dimensional systems, demonstrating numerically that the spatiotemporal chaos in several simple models is extensive(6-8) (the number of dynamical degrees of freedom scales with the system volume). Here we report a computational investigation of a phenomenon found in nature, 'spiral defect' chaos(5,9) in Rayleigh-Benard convection, in which we rnd that the spatiotemporal chaos in this state is extensive and characterized by about a hundred dynamical degrees of freedom. By studying the detailed space-time evolution of the dynamical degrees of freedom, we rnd that the mechanism for the generation of chaotic disorder is spatially and temporally localized to events associated with the creation and annihilation of defects. C1 Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Div Theoret, Los Alamos, NM 87545 USA. Univ Bayreuth, Inst Phys, D-95440 Bayreuth, Germany. RP Egolf, DA (reprint author), Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Div Theoret, Los Alamos, NM 87545 USA. OI Ecke, Robert/0000-0001-7772-5876 NR 24 TC 82 Z9 83 U1 1 U2 28 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD APR 13 PY 2000 VL 404 IS 6779 BP 733 EP 736 DI 10.1038/35008013 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 305DF UT WOS:000086523600043 ER PT J AU Sharma, RP Ogale, SB Zhang, ZH Liu, JR Chu, WK Veal, B Paulikas, A Zheng, H Venkatesan, T AF Sharma, RP Ogale, SB Zhang, ZH Liu, JR Chu, WK Veal, B Paulikas, A Zheng, H Venkatesan, T TI Phase transitions in the incoherent lattice fluctuations in YBa2Cu3O7-delta SO NATURE LA English DT Editorial Material ID T-J MODEL; SPIN-GAP; DYNAMICS; SUPERCONDUCTORS; DISTORTIONS; LA2-XSRXCUO4; CRYSTALS; RANGE; HOLES AB The growing body of experimental evidence(1-7) for the existence of complex textures of charges and spins in the high-temperature superconductors has drawn attention to the so-called 'stripe-phase' model(8-12) as a possible basis for the mechanism of superconductivity in these materials. Such observations have until now been restricted to systems where the texture dynamics are slow or suppressed altogether, and do not include the important case of YBa2Cu3O7-delta. It seems likely that the dynamic behaviour of stripes(12,13), which has been suggested to undergo several phase transitions as a function of temperature(12), should also be reflected in the lattice properties of the host materials, and this forms the motivation for our present experiments. Specifically, we use MeV helium ion channelling, an ultrafast real-space probe of atomic displacements (with sub-picometre resolution), to probe incoherent lattice fluctuations in YBa2Cu3O7-delta as a function of temperature and oxygen doping. We detect lattice fluctuations that are larger than the expected thermal vibration component, and which show anomalies characteristic of the phase transitions anticipated for a dynamic stripe phase. Comparison of our lattice results with single-particle-tunnelling and photoemission data highlights the importance of spin-charge separation phenomena in the copper oxide superconductors. C1 Univ Maryland, Ctr Superconduct Res, Dept Phys, College Pk, MD 20742 USA. Univ Houston, Texas Ctr Superconduct, Houston, TX 77204 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Venkatesan, T (reprint author), Univ Maryland, Ctr Superconduct Res, Dept Phys, College Pk, MD 20742 USA. RI Venkatesan, Thirumalai/E-1667-2013 NR 29 TC 96 Z9 97 U1 0 U2 12 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD APR 13 PY 2000 VL 404 IS 6779 BP 736 EP 740 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 305DF UT WOS:000086523600044 ER PT J AU Yamamoto, K Alburger, DE Barnes, PD Bassalleck, B Berdoz, AR Biglan, A Burger, T Carman, DS Chrien, RE Davis, CA Fischer, H Franklin, GB Franz, J Gan, L Ichikawa, A Iijima, T Imai, K Khaustov, P Kondo, Y Koran, P Landry, M Lee, L Lowe, J Magahiz, R May, M McCrady, R Merrill, F Meyer, CA Page, SA Paschke, K Pile, PH Quinn, BP Ramsay, WD Rusek, A Sawafta, R Schmitt, H Schumacher, RA Stotzer, RW Sutter, R Takeutchi, F van Oers, WTH Yosoi, M Zeps, VJ AF Yamamoto, K Alburger, DE Barnes, PD Bassalleck, B Berdoz, AR Biglan, A Burger, T Carman, DS Chrien, RE Davis, CA Fischer, H Franklin, GB Franz, J Gan, L Ichikawa, A Iijima, T Imai, K Khaustov, P Kondo, Y Koran, P Landry, M Lee, L Lowe, J Magahiz, R May, M McCrady, R Merrill, F Meyer, CA Page, SA Paschke, K Pile, PH Quinn, BP Ramsay, WD Rusek, A Sawafta, R Schmitt, H Schumacher, RA Stotzer, RW Sutter, R Takeutchi, F van Oers, WTH Yosoi, M Zeps, VJ CA E885 Collaboration TI Search for double-Lambda hypernuclei and the H-dibaryon in the (K-, K+) reaction on C-12 SO PHYSICS LETTERS B LA English DT Article ID K-,K+ REACTION; PARTICLE SEARCHES; BNL AB A search for double-Lambda hypernuclei (Be-12(Lambda Lambda)) and H-dibaryons using the C-12(K-,K+) reaction was perlormeu at the BNL-AGS using a high-intensity 1.8 GeV/c K- beam. A missing-mass analysis below the end point of the quasi-free Xi(-) was used to investigate these S = -2 systems, The upper limit obtained for the forward-angle cross section of (12)(Lambda Lambda) Be production is 6 to 10 nb/sr. This is the first search for the direct production of double-Lambda hypernuclei to reach the sensitivity required to observe the signal predicted by theoretical calculations. For the H-production cross section, we have obtained an upper limit in the range of a few nb/sr to 10 nb/sr for the H mass below 2100 MeV/c(2.) This upper limit is the most sensitive H search result to date for a tightly bound H. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Univ Birmingham, Dept Phys, Birmingham B15 2TT, W Midlands, England. Brookhaven Natl Lab, Upton, NY 11973 USA. Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15213 USA. Univ Freiburg, Fak Phys, D-79104 Freiburg, Germany. High Energy Accelerator Res Org, KEK, Tsukuba, Ibaraki 3050801, Japan. Univ Kentucky, Dept Phys & Astron, Lexington, KY 40507 USA. Kyoto Univ, Dept Phys, Sakyo Ku, Kyoto 6068502, Japan. Kyoto Sangyo Univ, Fac Sci, Kyoto 6038555, Japan. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Manitoba, Dept Phys, Winnipeg, MB R3T 2N2, Canada. Univ New Mexico, Dept Phys & Astron, Albuquerque, NM 87131 USA. TRIUMF, Vancouver, BC V6T 2A3, Canada. RP Yamamoto, K (reprint author), Osaka City Univ, Dept Phys, Osaka 5588585, Japan. RI Schumacher, Reinhard/K-6455-2013; Meyer, Curtis/L-3488-2014; Franklin, Gregg/N-7743-2014; Quinn, Brian/N-7343-2014 OI Schumacher, Reinhard/0000-0002-3860-1827; Meyer, Curtis/0000-0001-7599-3973; Franklin, Gregg/0000-0003-4176-1378; Quinn, Brian/0000-0003-2800-986X NR 29 TC 28 Z9 28 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 APR 13 PY 2000 VL 478 IS 4 BP 401 EP 407 DI 10.1016/S0370-2693(00)00299-9 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 305LC UT WOS:000086540700001 ER PT J AU Liang, WC Roelofs, TA Cinco, RM Rompel, A Latimer, MJ Yu, WO Sauer, K Klein, MP Yachandra, VK AF Liang, WC Roelofs, TA Cinco, RM Rompel, A Latimer, MJ Yu, WO Sauer, K Klein, MP Yachandra, VK TI Structural change of the Mn cluster during the S-2 -> S-3 state transition of the oxygen-evolving complex of photosystem II. Does it reflect the onset of water/substrate oxidation? Determination by Mn X-ray absorption spectroscopy SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID PHOTOSYNTHETIC WATER OXIDATION; MANGANESE CLUSTER; FINE-STRUCTURE; O-2-EVOLVING COMPLEX; MULTIPLE-SCATTERING; REDUCED DERIVATIVES; CALCIUM DEPLETION; AMMONIA BINDS; S-2 STATE; S0 STATE AB The oxygen-evolving complex of Photosystem II in plants and cyanobacteria catalyzes the oxidation of two water molecules to one molecule of dioxygen. A tetranuclear Mn complex is believed to cycle through five intermediate states (S-0-S-4) to couple the four-electron oxidation of water with the one-electron photochemistry occurring at the Photosystem II reaction center. We have used X-ray absorption spectroscopy to study the local structure of the Mn complex and have proposed a model for it, based on studies of the Mn K-edges and the extended X-ray absorption fine structure of the S-1 and S-2 states. The proposed model consists of two di-mu-oxo-bridged binuclear Mn units with Mn-Mn distances of similar to 2.7 Angstrom that are linked to each other by a mono-mu-oxo bridge with a Mn-Mn separation of similar to 3.3 Angstrom. The Mn-Mn distances are invariant in the native S-1 and S-2 states. This report describes the application of X-ray absorption spectroscopy to S-3 samples created under physiological conditions with saturating flash illumination. Significant changes are observed in the Mn-Mn distances in the S-3 State compared to the S-1 and the S-2 states. The two 2.7 Angstrom Mn-Mn distances that characterize the di-mu-oxo centers in the S-1 and S-2 states are lengthened to similar to 2.8 and 3.0 Angstrom in the S-3 state, respectively. The 3.3 Angstrom Mn-Mn and Mn-Ca distances also increase by 0.04-0.2 Angstrom. These changes in Mn-Mn distances are interpreted as consequences of the onset of substrate/water oxidation in the S-3 state. Mn-centered oxidation is evident during the S-0-->S-1 and S-1-->S-2 transitions. We propose that the changes in Mn-Mn distances during the S-2-->S-3 transition are the result of Ligand or water oxidation, leading to the formation of an oxyl radical intermediate formed at a bridging or terminal position. The reaction of the oxyl radical with OH-, H2O, or an oxo group during the subsequent S state conversion is proposed to lead to the formation of the O-O bond. Models that can account for changes in the Mn-Mn distances in the S-3 state and the implications for the mechanism of water oxidation are discussed. C1 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 Liang, WC (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Melvin Calvin Lab, Berkeley, CA 94720 USA. FU NIGMS NIH HHS [R56 GM055302, R01 GM055302] NR 90 TC 121 Z9 122 U1 0 U2 19 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 APR 12 PY 2000 VL 122 IS 14 BP 3399 EP 3412 DI 10.1021/ja992501u PG 14 WC Chemistry, Multidisciplinary SC Chemistry GA 304HF UT WOS:000086477100017 PM 25152534 ER PT J AU Krueger, JK Gallagher, SC Wang, CLA Trewhella, J AF Krueger, JK Gallagher, SC Wang, CLA Trewhella, J TI Calmodulin remains extended upon binding to smooth muscle caldesmon: A combined small-angle scattering and Fourier transform infrared spectroscopy study SO BIOCHEMISTRY LA English DT Article ID LIGHT-CHAIN KINASE; X-RAY-SCATTERING; TROPONIN-C; NEUTRON-SCATTERING; SKELETAL-MUSCLE; THIN-FILAMENTS; PHOSPHORYLASE-KINASE; SHAPE DETERMINATION; CATALYTIC SUBUNIT; PEPTIDE COMPLEX AB We show that calmodulin (CaM) has an extended conformation in its complexes with sequences from the smooth muscle thin filament protein caldesmon (CaD) by using small-angle X-ray and neutron scattering with contrast variation. The CaD sequences used in these experiments were a C-terminal fragment, 22kCaD, and a smaller peptide sequence within this fragment, MG56C, Each of these sequences contains the CaM-binding sites A and B previously shown to interact with the C- and N-terminal lobes of CaM, respectively [Wang ct al, (1997) Biochemistry 36, 15026]. By modeling the scattering data, we show that the majority of the MG56C sequence binds to the N-terminal domain of CaM. FTIR data on CaM complexed with 22kCaD or with MG56C peptide show the 22kCaD sequence contains unordered, helix, and extended structures, and that the extended structures reside primarily in the MG56C portion of the sequence. There are small changes in secondary structure, involving similar to 12 residues, induced by CaM binding to CaD, These changes involve a net decrease in extended structures accompanied by an increase in alpha-helix, and they occur within the CaM and/or in the MG56C sequence. C1 Univ Calif Los Alamos Natl Lab, Biosci Div, Los Alamos, NM 87545 USA. Boston Biomed Res Inst, Boston, MA 02114 USA. RP Trewhella, J (reprint author), Univ Calif Los Alamos Natl Lab, Biosci Div, Mail Stop M888, Los Alamos, NM 87545 USA. RI Krueger, Joanna/A-3110-2011; OI Trewhella, Jill/0000-0002-8555-6766 FU NIAMS NIH HHS [AR41637]; NIGMS NIH HHS [GM40528] NR 56 TC 24 Z9 24 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD APR 11 PY 2000 VL 39 IS 14 BP 3979 EP 3987 DI 10.1021/bi992638x PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 304HV UT WOS:000086478400014 PM 10747786 ER PT J AU Temple, CA George, GN Hilton, JC George, MJ Prince, RC Barber, MJ Rajagopalan, KV AF Temple, CA George, GN Hilton, JC George, MJ Prince, RC Barber, MJ Rajagopalan, KV TI Structure of the molybdenum site of Rhodobacter sphaeroides biotin sulfoxide reductase SO BIOCHEMISTRY LA English DT Article ID RAY-ABSORPTION SPECTROSCOPY; FORMATE DEHYDROGENASE-H; CRYSTAL-STRUCTURE; ESCHERICHIA-COLI; NUCLEOTIDE-SEQUENCE; DMSO REDUCTASE; ANGSTROM RESOLUTION; SP DENITRIFICANS; MOLYBDOPTERIN; CAPSULATUS AB Conditions for heterologous expression of Rhodobacter sphaeroides biotin sulfoxide reductase in Escherichia coli were modified, resulting in a significant improvement in the yield of recombinant enzyme and enabling structural studies of the molybdenum center. Quantitation of the guanine and the molybdenum as compared to that found in R. sphaeroides DMSO reductase demonstrated the presence of the bis(MGD)molybdenum cofactor. UV-visible absorption spectra were obtained for the oxidized, NADPH-reduced, and dithionite-reduced enzyme. EPR spectra were obtained for the Mo(V) state of the enzyme. X-ray absorption spectroscopy at the molybdenum K-edge has been used to probe the molybdenum coordination of the enzyme. The molybdenum site of the oxidized protein possesses a Mo(VI) mono-ore site (Mo=O at 1.70 Angstrom) with additional coordination by approximately four thiolate ligands at 2.41 Angstrom and probably one oxygen or nitrogen at 1.95 Angstrom. The NADPH- and dithionite-reduced Mo(IV) forms of the enzyme are des-oxo molybdenum sites with approximately four thiolates at 2.33 Angstrom and two different Mo-O/N ligands at 2.19 and 1.94 Angstrom. C1 Duke Univ, Med Ctr, Dept Biochem, Durham, NC 27710 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. Exxon Res & Engn Co, Annandale, NJ 08801 USA. Univ S Florida, Coll Med, Dept Biochem & Mol Biol, Tampa, FL 33612 USA. Univ S Florida, H Lee Moffitt Canc Ctr & Res Inst, H Lee Moffitt Canc Ctr & Res Inst, Tampa, FL 33612 USA. RP Rajagopalan, KV (reprint author), Duke Univ, Med Ctr, Dept Biochem, Durham, NC 27710 USA. RI George, Graham/E-3290-2013 FU NIGMS NIH HHS [GM00091] NR 26 TC 27 Z9 27 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD APR 11 PY 2000 VL 39 IS 14 BP 4046 EP 4052 DI 10.1021/bi9921541 PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 304HV UT WOS:000086478400021 PM 10747793 ER PT J AU Branchini, E Zehavi, I Plionis, M Dekel, A AF Branchini, E Zehavi, I Plionis, M Dekel, A TI Cluster versus POTENT density and velocity fields: cluster biasing and Omega SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE galaxies : clusters : general; galaxies : kinematics and dynamics; cosmology : theory; large-scale structure of Universe ID PECULIAR VELOCITIES; IRAS-GALAXIES; RECONSTRUCTING POSITIONS; 25,000 KILOMETERS; OPTICAL GALAXIES; REDSHIFT SURVEY; RICH CLUSTERS; DIPOLE; MASS; CATALOGS AB The density and velocity fields as extracted from the Abell/ACO clusters are compared with the corresponding fields recovered by the POTENT method from the Mark III peculiar velocities of galaxies. In order to minimize non-linear effects and to deal with ill-sampled regions, we smooth both fields using a Gaussian window with radii ranging between 12 and 20 h(-1) Mpc. The density and velocity fields within 70 h(-1) Mpc exhibit similarities, qualitatively consistent with gravitational instability theory and a linear biasing relation between clusters and mass. The random and systematic errors are evaluated with the help of mock catalogues. Quantitative comparisons within a volume containing similar to 12 independent samples yield beta(c)=Omega(0.6)/b(c)=0.22 +/- 0.08, where b(c) is the cluster biasing parameter at 15 h(-1) Mpc. If b(c)similar to 4.5, as indicated by the cluster correlation function, our result is consistent with Omega similar to 1. C1 Univ Durham, Dept Phys, Durham DH1 3LE, England. Univ Groningen, Kapteyn Astron Inst, NL-9700 AV Groningen, Netherlands. Fermi Natl Accelerator Lab, NASA, Fermilab Astrophys Grp, Batavia, IL 60510 USA. Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. Natl Observ Athens, Athens 18110, Greece. Sch Adv Int Studies, SISSA, I-34013 Trieste, Italy. RP Branchini, E (reprint author), Univ Durham, Dept Phys, South Rd, Durham DH1 3LE, England. RI Plionis, Manolis/K-4354-2013; OI Branchini, Enzo/0000-0002-0808-6908 NR 51 TC 18 Z9 18 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD APR 11 PY 2000 VL 313 IS 3 BP 491 EP 503 DI 10.1046/j.1365-8711.2000.03257.x PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 302WU UT WOS:000086390100006 ER PT J AU Gabuzda, DC Kochenov, PY Cawthorne, TV Kollgaard, RI AF Gabuzda, DC Kochenov, PY Cawthorne, TV Kollgaard, RI TI Intraday polarization variability outside the VLBI core of the active galactic nucleus 0716+714 SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE polarization; galaxies : active; BL Lacertae objects : individual : 0716+714; radio continuum : galaxies ID BL-LACERTAE; RADIO-SOURCES; INTERSTELLAR SCINTILLATION; ANOMALOUS REDSHIFTS; RAPID VARIABILITY; SPECTRUM; OBJECTS; MODEL AB Rapid ('intraday') cm-wavelength variations in both total and polarized flux density have been observed in a number of strong extragalactic radio sources. It is difficult to explain these variations purely as propagation effects, but if they are intrinsic to the sources, implausibly high brightness temperatures are required. We discuss here rapid polarization variability during our lambda=6 cm global very long-baseline interferometry (VLBI) observations of the active galactic nucleus 0716+714. Measurements made with the Very Large Array (VLA) during the VLBI observations indicate a similar or equal to 50 degrees swing in the position angle chi of the VLA core polarization in 12 hours. Corresponding variations were observed only for short VLBI baselines, so that they could not have occurred in the VLBI core (the only feature detected in our VLBI polarization map). The fact that the variations appear both in the VLA data and in the VLBI data for short baselines makes it difficult to explain them as instrumental effects. This leads us to conclude that the rapid variations occurred outside the area covered by our VLBI map; we estimate that the variability occurred in some compact feature roughly 25 milliarcseconds from the nucleus. It is clear that compact structures on a wide range of scales must be taken into account in studies of intraday variability in AGN. C1 Joint Inst VLBI Europe, NL-7990 AA Dwingeloo, Netherlands. PN Lebedev Phys Inst, Ctr Astro Space, Moscow 117924, Russia. Univ Cent Lancashire, Dept Phys & Astron, Preston PR1 2HE, Lancs, England. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Gabuzda, DC (reprint author), Joint Inst VLBI Europe, Postbus 2, NL-7990 AA Dwingeloo, Netherlands. NR 22 TC 21 Z9 21 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD APR 11 PY 2000 VL 313 IS 3 BP 627 EP 636 DI 10.1046/j.1365-8711.2000.03309.x PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 302WU UT WOS:000086390100019 ER PT J AU Ullom, JN Cunningham, MF Drury, OB Frank, M Friedrich, S Labov, SE Fisher, PA Gifford, P AF Ullom, JN Cunningham, MF Drury, OB Frank, M Friedrich, S Labov, SE Fisher, PA Gifford, P TI Novel refrigerator development SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 8th International Workshop on Low-Temperature Detectors (LTD-8) CY AUG 15-20, 1999 CL DALFSEN, NETHERLANDS SP Technol Fdn, European Space Technol Ctr, Space Res Org Netherlands ID TUNNEL JUNCTION AB In Section 1, we describe how the creation of quasiparticles by current flow through a normal-insulator-superconductor (NIS) junction degrades the cooling performance of the junction. Degradation occurs due to the absorption of recombination phonons in the normal electrode and due to a reduction in the cooling power. In Section 2, we describe how vibrations from a pulse tube mechanical cooler affect X-ray measurements performed with a superconducting tunnel junction. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Analog Devices Corp, Wilmington, MA 01887 USA. Cryomech Inc, Syracuse, NY 13211 USA. RP Ullom, JN (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RI Frank, Matthias/O-9055-2014 NR 6 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 11 PY 2000 VL 444 IS 1-2 BP 38 EP 41 DI 10.1016/S0168-9002(99)01323-6 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 310JU UT WOS:000086823400010 ER PT J AU Nucciotti, A Alessandrello, A Beeman, JW Brofferio, C Cremonesi, O Fiorini, E Giuliani, A Haller, EE Losi, D Margesin, B Monfardini, A Pavan, M Pessina, G Previtali, E Zanotti, L Pignatel, G Zen, M AF Nucciotti, A Alessandrello, A Beeman, JW Brofferio, C Cremonesi, O Fiorini, E Giuliani, A Haller, EE Losi, D Margesin, B Monfardini, A Pavan, M Pessina, G Previtali, E Zanotti, L Pignatel, G Zen, M TI Neutrino mass measurement with an array of high-resolution AgReO4 microcalorimeters SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 8th International Workshop on Low-Temperature Detectors (LTD-8) CY AUG 15-20, 1999 CL DALFSEN, NETHERLANDS SP Technol Fdn, European Space Technol Ctr, Space Res Org Netherlands AB We report here the preparation of an experiment to measure the electronic anti-neutrino mass by studying the Re-187 end-point with high-resolution thermal microcalorimeters. We present the results achieved up to now with several AgReO4 microcalorimeter prototypes and we discuss the experiment perspective regarding both the detector performances and the achievable neutrino mass sensitivity. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Milan, Dipartimento Fis, I-20133 Milan, Italy. Ist Nazl Fis Nucl, Sez Milano, I-20133 Milan, Italy. Univ Trent, Dipartimento Ingn Mat, I-38050 Povo, TN, Italy. IRST, I-38050 Povo, TN, Italy. Univ Calif Berkeley, Dept Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Nucciotti, A (reprint author), Univ Milan, Dipartimento Fis, Via Celoria 16, I-20133 Milan, Italy. RI Nucciotti, Angelo/I-8888-2012; Margesin, Benno/K-5826-2015; OI Nucciotti, Angelo/0000-0002-8458-1556; Margesin, Benno/0000-0002-1120-3968; Pessina, Gianluigi Ezio/0000-0003-3700-9757 NR 6 TC 14 Z9 14 U1 0 U2 2 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 APR 11 PY 2000 VL 444 IS 1-2 BP 77 EP 79 DI 10.1016/S0168-9002(99)01332-7 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 310JU UT WOS:000086823400018 ER PT J AU Friedrich, S Cunningham, MF Frank, M Labov, SE Barfknecht, AT Cramer, SP AF Friedrich, S Cunningham, MF Frank, M Labov, SE Barfknecht, AT Cramer, SP TI Fiske modes in superconducting tunnel junction detectors SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 8th International Workshop on Low-Temperature Detectors (LTD-8) CY AUG 15-20, 1999 CL DALFSEN, NETHERLANDS SP Technol Fdn, European Space Technol Ctr, Space Res Org Netherlands DE cryogenic X-ray detectors; superconducting tunnel junctions; Fiske modes ID X-RAY SPECTROMETERS; HIGH-RESOLUTION; PARTICLE DETECTORS; ENERGY RESOLUTION; MICROANALYSIS; SPECTROSCOPY; PERFORMANCE AB We are developing superconducting tunnel junction (STJ) X-ray spectrometers with high-energy resolution( < 10 eV for keV X-rays) and high count rate capabilities ( > 10 000 counts/s). We have examined the influence of Fiske mode resonances on energy resolution, maximum count rate and area of Nb-Al-AlOx-Al-Nb STJ detectors. At low count rate, these detectors have an energy resolution of 2.3 eV FWHM at 70 eV. At 20 000 counts/s, the resolution is 8.2 eV FWHM at 277 eV. We observe the optimum detector performance when the influence of Fiske modes is minimized. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Conductus Inc, Sunnyvale, CA 94086 USA. RP Friedrich, S (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-418, Livermore, CA 94550 USA. RI Frank, Matthias/O-9055-2014 NR 20 TC 12 Z9 12 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 11 PY 2000 VL 444 IS 1-2 BP 151 EP 155 DI 10.1016/S0168-9002(99)01348-0 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 310JU UT WOS:000086823400035 ER PT J AU Silver, E Schnopper, H Bandler, S Murray, S Madden, N Landis, D Beeman, J Haller, E Barbera, M Tucker, G Gillaspy, J Takacs, E Porto, J AF Silver, E Schnopper, H Bandler, S Murray, S Madden, N Landis, D Beeman, J Haller, E Barbera, M Tucker, G Gillaspy, J Takacs, E Porto, J TI Laboratory astrophysics and microanalysis with NTD-germanium-based X-ray microcalorimeters SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 8th International Workshop on Low-Temperature Detectors (LTD-8) CY AUG 15-20, 1999 CL DALFSEN, NETHERLANDS SP Technol Fdn, European Space Technol Ctr, Space Res Org Netherlands AB With the ability to create cosmic plasma conditions in the laboratory it is possible to investigate the dependencies of key diagnostic X-ray lines on density, temperature, and excitation conditions that exist in astrophysical sources with X-ray optics and a high-resolution X-ray microcalorimeter. The same instrumentation call be coupled to scanning electron microscopes or X-ray fluorescence probes to analyze the elemental and chemical composition of electronic, biological, geological and particulate materials. We describe how our microcalorimeter and X-ray optics provide significantly improved capabilities for laboratory astrophysics and microanalysis. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Brown Univ, Providence, RI 02912 USA. Osservatorio Astron Palermo, Palermo, Italy. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Silver, E (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI Bandler, Simon/A-6258-2010; OI Bandler, Simon/0000-0002-5112-8106; Barbera, Marco/0000-0002-3188-7420 NR 8 TC 16 Z9 16 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 APR 11 PY 2000 VL 444 IS 1-2 BP 156 EP 160 DI 10.1016/S0168-9002(99)01349-2 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 310JU UT WOS:000086823400036 ER PT J AU Chow, DT Lindeman, MA Cunningham, MF Frank, M Barbee, TW Labov, SE AF Chow, DT Lindeman, MA Cunningham, MF Frank, M Barbee, TW Labov, SE TI Gamma-ray spectrometers using a bulk Sn absorber coupled to a Mo/Cu multilayer superconducting transition edge sensor SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 8th International Workshop on Low-Temperature Detectors (LTD-8) CY AUG 15-20, 1999 CL DALFSEN, NETHERLANDS SP Technol Fdn, European Space Technol Ctr, Space Res Org Netherlands AB We are developing gamma-ray detectors with a bulk absorber and a superconducting transition-edge sensor. The absorber is high-purity Sn and the transition-edge sensor is a Mo/Cu multilayer thin film. We have characterized the detector. and will discuss X- and gamma-ray results. Published by Elsevier Science B.V. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Davis, Dept Appl Sci, Livermore, CA 94550 USA. RP Chow, DT (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RI Frank, Matthias/O-9055-2014 NR 5 TC 20 Z9 20 U1 0 U2 4 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 APR 11 PY 2000 VL 444 IS 1-2 BP 196 EP 200 DI 10.1016/S0168-9002(99)01357-1 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 310JU UT WOS:000086823400044 ER PT J AU Bandler, S Silver, E Schnopper, H Murray, S Barbera, M Madden, N Landis, D Beeman, J Haller, E Tucker, G AF Bandler, S Silver, E Schnopper, H Murray, S Barbera, M Madden, N Landis, D Beeman, J Haller, E Tucker, G TI NTD-GE-based microcalorimeter performance SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 8th International Workshop on Low-Temperature Detectors (LTD-8) CY AUG 15-20, 1999 CL DALFSEN, NETHERLANDS SP Technol Fdn, European Space Technol Ctr, Space Res Org Netherlands ID RAY AB Our group has been developing X-ray microcalorimeters consisting of neutron transmutation-doped (NTD) germanium thermistors attached to superconducting tin absorbers. We discuss the performance of single pixel X-rap detectors, and describe an array technology. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Osservatorio Astron Palermo, Palermo, Italy. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Brown Univ, Providence, RI 02912 USA. RP Bandler, S (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI Bandler, Simon/A-6258-2010; OI Bandler, Simon/0000-0002-5112-8106; Barbera, Marco/0000-0002-3188-7420 NR 6 TC 10 Z9 10 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 APR 11 PY 2000 VL 444 IS 1-2 BP 273 EP 277 DI 10.1016/S0168-9002(99)01389-3 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 310JU UT WOS:000086823400062 ER PT J AU Shutt, T Emes, J Haller, EE Hellmig, J Sadoulet, B Seitz, D Young, BA White, S AF Shutt, T Emes, J Haller, EE Hellmig, J Sadoulet, B Seitz, D Young, BA White, S TI A solution to the dead-layer problem in ionization and phonon-based dark matter detectors SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 8th International Workshop on Low-Temperature Detectors (LTD-8) CY AUG 15-20, 1999 CL DALFSEN, NETHERLANDS SP Technol Fdn, European Space Technol Ctr, Space Res Org Netherlands AB We report on a study of several different electrode technologies to avoid the "dead-layer" problem in ionization and phonon-based dark matter detectors. We have found the most success with an amorphous blocking-layer electrode structure, and have demonstrated background electron rejection of approximate to 95% above 20 keV. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Ctr Particle Astrophys, Berkeley, CA 94720 USA. Santa Clara Univ, Dept Phys, Santa Clara, CA 95053 USA. RP Shutt, T (reprint author), Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. NR 6 TC 54 Z9 54 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 11 PY 2000 VL 444 IS 1-2 BP 340 EP 344 DI 10.1016/S0168-9002(99)01379-0 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 310JU UT WOS:000086823400078 ER PT J AU Golwala, SR Abusaidi, R Akerib, DS Barnes, PD Bauer, DA Bolozdynya, A Brink, P Cabrera, B Caldwell, DO Castle, JP Clarke, RM Colling, P Crisler, MB Da Silva, A Davies, AK Dixon, R Eichblatt, S Irwin, KD Gaitskell, RJ Haller, EE Hellmig, J Huber, ME Jochum, J Lipschultz, FP Martinis, J Nam, SW Nelson, J Neuhauser, B Perera, TA Isaac, MP Ross, RR Saab, T Sadoulet, B Schnee, RW Shestople, P Shutt, T Smith, A Sonnenschein, AH Spadafora, AL Yellin, S Young, BA AF Golwala, SR Abusaidi, R Akerib, DS Barnes, PD Bauer, DA Bolozdynya, A Brink, P Cabrera, B Caldwell, DO Castle, JP Clarke, RM Colling, P Crisler, MB Da Silva, A Davies, AK Dixon, R Eichblatt, S Irwin, KD Gaitskell, RJ Haller, EE Hellmig, J Huber, ME Jochum, J Lipschultz, FP Martinis, J Nam, SW Nelson, J Neuhauser, B Perera, TA Isaac, MP Ross, RR Saab, T Sadoulet, B Schnee, RW Shestople, P Shutt, T Smith, A Sonnenschein, AH Spadafora, AL Yellin, S Young, BA TI Exclusion limits on the WIMP-nucleon scattering cross-section from the Cryogenic Dark Matter Search SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 8th International Workshop on Low-Temperature Detectors (LTD-8) CY AUG 15-20, 1999 CL DALFSEN, NETHERLANDS SP Technol Fdn, European Space Technol Ctr, Space Res Org Netherlands AB The Cryogenic Dark Matter Search (CDMS) employs massive ionization- and phonon-mediated detectors to search for WIMPs via their elastic scattering interactions with nuclei while discriminating against interactions by other background particles. Limits on the WIMP-nucleon scattering cross-section, based on 3.1 kg d of exposure, exclude new parameter space in the 10-30 GeV WIMP mass region and also a portion of the region allowed by the DAMA annual modulation search (Bernabei, Phys. Lett. 450 (1999) 448). (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Ctr Particle Astrophys, Berkeley, CA 94720 USA. Stanford Univ, Dept Phys, Stanford, CA 94305 USA. Case Western Reserve Univ, Dept Phys, Cleveland, OH 44106 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Natl Inst Stand & Technol, Boulder, CO 80303 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Colorado, Dept Phys, Denver, CO 80217 USA. San Francisco State Univ, Dept Phys & Astron, San Francisco, CA 94132 USA. Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. RP Golwala, SR (reprint author), Univ Calif Berkeley, Ctr Particle Astrophys, Berkeley, CA 94720 USA. RI Huber, Martin/B-3354-2011 NR 12 TC 32 Z9 32 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 APR 11 PY 2000 VL 444 IS 1-2 BP 345 EP 349 DI 10.1016/S0168-9002(99)01388-1 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 310JU UT WOS:000086823400079 ER PT J AU Frank, M AF Frank, M TI Mass spectrometry with cryogenic detectors SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 8th International Workshop on Low-Temperature Detectors (LTD-8) CY AUG 15-20, 1999 CL DALFSEN, NETHERLANDS SP Technol Fdn, European Space Technol Ctr, Space Res Org Netherlands DE cryogenic detectors; calorimetric detectors; high-mass detectors; time-of-flight mass spectrometry ID SECONDARY-ELECTRON EMISSION; LARGE MOLECULAR-IONS; LASER-DESORPTION; TIME; ENERGY; SURFACES; IMPACT AB Cryogenic detectors have recently been applied for the first time as ion detectors in time-of-flight mass spectrometry (TOF-MS). Because of their energy sensitivity cryogenic detectors are expected to have near 100% efficiency even for very large, slow-moving molecules, in contrast to microchannel plates whose efficiency drops considerably at large mass. Thus, cryogenic detectors could contribute to extending the mass range accessible by TOF-MS and help improving detection limits. In addition, the energy resolution provided by cryogenic detectors can be used for charge discrimination and studies of ion fragmentation, ion-detector interaction, and internal energies of large molecular ions. Cryogenic detectors could therefore prove to be a valuable diagnostic tool in TOF-MS. Here I summarize the results of recent demonstration experiments. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Phys Directorate, Div 5, Livermore, CA 94551 USA. RP Frank, M (reprint author), Univ Calif Lawrence Livermore Natl Lab, Phys Directorate, Div 5, Mail Stop L-418,POB 808, Livermore, CA 94551 USA. RI Frank, Matthias/O-9055-2014 NR 34 TC 10 Z9 10 U1 0 U2 3 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 APR 11 PY 2000 VL 444 IS 1-2 BP 375 EP 384 DI 10.1016/S0168-9002(99)01409-6 PG 10 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 310JU UT WOS:000086823400086 ER PT J AU Ullom, JN Frank, M Horn, JM Labov, SE Langry, K Benner, WH AF Ullom, JN Frank, M Horn, JM Labov, SE Langry, K Benner, WH TI Identification of microorganisms using superconducting tunnel junctions and time-of-flight mass spectrometry SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 8th International Workshop on Low-Temperature Detectors (LTD-8) CY AUG 15-20, 1999 CL DALFSEN, NETHERLANDS SP Technol Fdn, European Space Technol Ctr, Space Res Org Netherlands ID DETECTORS AB We present time-of-flight measurements of biological material ejected from bacterial spores following laser irradiation. Ion impacts are registered on a microchannel plate detector and on a Superconducting Tunnel Junction (STJ) detector. We compare mass spectra obtained with the two detectors. The STJ has better sensitivity to massive ions and also measures the energy of each ion. We show evidence that spores of different bacillus species produce distinctive mass spectra and associate the observed mass peaks with coat proteins. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Ullom, JN (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RI Frank, Matthias/O-9055-2014 NR 7 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 11 PY 2000 VL 444 IS 1-2 BP 385 EP 388 DI 10.1016/S0168-9002(99)01411-4 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 310JU UT WOS:000086823400087 ER PT J AU Sudiwala, RV Maffei, B Griffin, MJ Haynes, CV Ade, PAR Bhatia, RS Turner, AD Bock, JJ Lange, AE Beeman, JW AF Sudiwala, RV Maffei, B Griffin, MJ Haynes, CV Ade, PAR Bhatia, RS Turner, AD Bock, JJ Lange, AE Beeman, JW TI Evaluation of prototype 100 mK bolometric detector for Planck Surveyor SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 8th International Workshop on Low-Temperature Detectors (LTD-8) CY AUG 15-20, 1999 CL DALFSEN, NETHERLANDS SP Technol Fdn, European Space Technol Ctr, Space Res Org Netherlands DE spider web bolometer; Planck HFI ID NOISE AB The High-Frequency Instrument (HFI) for the Planck Surveyor mission will measure anisotropies of the Cosmic Microwave Background (CMB) down to scales of 6 arcmin and to an accuracy of Delta T/T = 2 x 10(-6). Channels ranging in frequency from 100 to 857 GHz will use 100 mK spider web bolometer detectors with NTD Ge thermistors, The detectors must be photon noise limited and fast enough to preserve signal information at the 1 r.p.m. scan rate of the satellite. The prime low-frequency CMB channels at 143 and 217 GHz are the most technically demanding owing to the lower background limited NEPs. For the 143 GHz channel the requirements are that the time constant tau < 5.7 ms and The NEPbol <1.53 x 10(-17) WHz(-1/2) including contribution from amplifier noise. We present here thermal, electrical and optical data on a prototype detector which, although optimised for the 100 GHz channel, satisfies most of the requirements of the more demanding 143 GHz channel. The measurements art: consistent with ideal thermal behaviour of the detector over the appropriate bias and temperature ranges for optimum performance. From optically blanked electrical measurements we determined the dependence of resistance and thermal conductance on temperature over a wide range, 70-200 mK. The optical responsivity and NEP were measured under photon background conditions similar to those expected in flight. Measurements of speed of response as a function of bias at different temperatures allowed us to determine the variation of total heat capacity with temperature. Extrapolation of these data show that in principal performance for all the Planck HFI channels can be met, (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ London Queen Mary & Westfield Coll, Dept Phys, London E1 4NS, England. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Sudiwala, RV (reprint author), Univ London Queen Mary & Westfield Coll, Dept Phys, Mile End Rd, London E1 4NS, England. NR 9 TC 7 Z9 7 U1 1 U2 2 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 APR 11 PY 2000 VL 444 IS 1-2 BP 408 EP 412 DI 10.1016/S0168-9002(99)01410-2 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 310JU UT WOS:000086823400091 ER PT J AU Barenblatt, GI Chorin, AJ Prostokishin, VM AF Barenblatt, GI Chorin, AJ Prostokishin, VM TI Characteristic length scale of the intermediate structure in zero-pressure-gradient boundary layer flow SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article AB In a turbulent boundary layer over a smooth flat plate with zero pressure gradient, the intermediate structure between the viscous sublayer and the free stream consists of two layers: one adjacent to the viscous sublayer and one adjacent to the free stream, When the level of turbulence in the free stream is low, the boundary between the two layers is sharp, and both have a self-similar structure described by Reynolds-number-dependent scaling (power) laws. This structure introduces two length scales: one-the wall-region thickness-determined by the sharp boundary between the two intermediate layers and the second determined by the condition that the velocity distribution in the first intermediate layer be the one common to all wall-bounded flows and in particular coincide with the scaling law previously determined for pipe flows, Using recent experimental data, we determine both these length scales and show that they are close, Our results disagree with the classical model of the "wake region." C1 Univ Calif Berkeley, Dept Math, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Russian Acad Sci, PP Shirshov Oceanol Inst, Moscow 117218, Russia. RP Barenblatt, GI (reprint author), Univ Calif Berkeley, Dept Math, Evans Hall,Room, Berkeley, CA 94720 USA. OI Prostokishin, Valeriy/0000-0001-6185-9642 NR 6 TC 7 Z9 8 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 APR 11 PY 2000 VL 97 IS 8 BP 3799 EP 3802 DI 10.1073/pnas.97.8.3799 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 304AV UT WOS:000086461100006 PM 10760253 ER PT J AU Shu, F Ramakrishnan, V Schoenborn, BP AF Shu, F Ramakrishnan, V Schoenborn, BP TI Enhanced visibility of hydrogen atoms by neutron crystallography on fully deuterated myoglobin SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID NUCLEAR MAGNETIC-RESONANCE; SPERM WHALE MYOGLOBIN; ESCHERICHIA-COLI; PROTEIN CRYSTALLOGRAPHY; DIFFRACTION ANALYSIS; EXPRESSION; RECONSTITUTION; APOMYOGLOBIN; HISTIDINES; BINDING AB Although hydrogens comprise half of the atoms in a protein molecule and are of great importance chemically and structurally, direct visualization of them by using crystallography is difficult. Neutron crystallography is capable of directly revealing the position of hydrogens, but its use on unlabeled samples faces certain technical difficulties: the large incoherent scattering of hydrogen results in background scattering that greatly reduces the signal to noise of the experiment. Moreover, whereas the scattering lengths of C, N, and O are positive, that of hydrogen is negative and about half the magnitude. This results in density for hydrogens being half as strong and close to the threshold of detection at 2.0-Angstrom resolution. Also, because of its opposite sign, there is a partial cancellation of the hydrogen density with that from neighboring atoms, which can lead to ambiguities in interpretation at medium resolution. These difficulties can be overcome by the use of deuterated protein, and we present here a neutron structure of fully deuterated myoglobin, The structure reveals a wealth of chemical information about the molecule, including the geometry of hydrogen bonding, states of protonation of histidines, and the location and geometry of water molecules at the surface of the protein. The structure also should be of broader interest because it will serve as a benchmark for molecular dynamics and energy minimization calculations and for comparison with NMR studies. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Schoenborn, BP (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. OI Ramakrishnan, V/0000-0002-4699-2194 NR 32 TC 83 Z9 84 U1 1 U2 6 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 APR 11 PY 2000 VL 97 IS 8 BP 3872 EP 3877 DI 10.1073/pnas.060024697 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 304AV UT WOS:000086461100019 PM 10725379 ER PT J AU Bilgin, A Zweig, G Marcellin, MW AF Bilgin, A Zweig, G Marcellin, MW TI Three-dimensional image compression with integer wavelet transforms SO APPLIED OPTICS LA English DT Article ID COEFFICIENTS; ZEROTREES; LOSSLESS AB dA three-dimensional (3-D) image-compression algorithm based on integer wavelet transforms and zerotree coding is presented. The embedded coding of zerotrees of wavelet coefficients (EZW) algorithm is extended to three dimensions, and context-based adaptive arithmetic coding is used to improve its performance. The resultant algorithm, 3-D CB-EZW, efficiently encodes 3-D image data by the exploitation of the dependencies in all dimensions, while enabling lossy and lossless decompression from the same bit stream. Compared with the best available two-dimensional lossless compression techniques, the 3-D CB-EZW algorithm produced averages of 22%, 25%, and 20% decreases in compressed die sizes for computed tomography, magnetic resonance, and Airborne Visible Infrared Imaging Spectrometer images, respectively. The progressive performance of the algorithm is also compared with other lossy progressive-coding algorithms. (C) 2000 Optical Society of America OCIS codes: 100.6890, 100.7410. C1 Univ Arizona, Dept Elect & Comp Engn, Tucson, AZ 85721 USA. Los Alamos Natl Lab, Div Theory, Los Alamos, NM 87545 USA. RP Univ Arizona, Dept Elect & Comp Engn, Tucson, AZ 85721 USA. EM bilgin@ece.arizona.edu NR 36 TC 70 Z9 71 U1 1 U2 4 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 APR 10 PY 2000 VL 39 IS 11 BP 1799 EP 1814 DI 10.1364/AO.39.001799 PG 16 WC Optics SC Optics GA 302ZV UT WOS:000086397100011 PM 18345077 ER PT J AU Fischer, AJ Chow, WW Choquette, KD Allerman, AA Geib, KM AF Fischer, AJ Chow, WW Choquette, KD Allerman, AA Geib, KM TI Q-switched operation of a coupled-resonator vertical-cavity laser diode SO APPLIED PHYSICS LETTERS LA English DT Article ID SURFACE-EMITTING LASERS; ABSORBER; DYNAMICS AB We report Q-switched operation from an electrically injected monolithic coupled-resonator structure which consists of an active cavity with InGaAs quantum wells optically coupled to a passive cavity. The passive cavity contains a bulk GaAs region which is reverse biased to provide variable absorption at the lasing wavelength of 990 nm. Cavity coupling is utilized to effect large changes in output intensity with only very small changes in passive cavity absorption. The device is shown to produce pulses as short as 150 ps at repetition rates as high as 4 GHz. A rate equation approach is used to model the Q-switched operation yielding good agreement between the experimental and theoretical pulse shape. Small-signal frequency response measurements also show a transition from a slower (similar to 300 MHz) forward-biased modulation regime to a faster (similar to 2 GHz) modulation regime under reverse-bias operation. (C) 2000 American Institute of Physics. [S0003-6951(00)01215-8]. C1 Sandia Natl Labs, Ctr Compound Semicond Sci & Technol, Albuquerque, NM 87185 USA. RP Fischer, AJ (reprint author), Sandia Natl Labs, Ctr Compound Semicond Sci & Technol, POB 5800, Albuquerque, NM 87185 USA. NR 13 TC 10 Z9 10 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 10 PY 2000 VL 76 IS 15 BP 1975 EP 1977 DI 10.1063/1.126227 PG 3 WC Physics, Applied SC Physics GA 301ER UT WOS:000086296200003 ER PT J AU Ma, Q Moldovan, N Mancini, DC Rosenberg, RA AF Ma, Q Moldovan, N Mancini, DC Rosenberg, RA TI Synchrotron-radiation-induced, selective-area deposition of gold on polyimide from solution SO APPLIED PHYSICS LETTERS LA English DT Article ID INDUCED METAL-DEPOSITION; LASER; FILMS AB Room-temperature photoinduced, selective-area deposition of gold films on polyimide from gold salt solution using synchrotron radiation x rays is described. A film growth rate as high as 40 nm/min is obtained. For thickness < 50 nm, the films consist of nanograins with a grain size of about 200 nm. For thicker films, gold deposit forms a ramified morphology on top of the nanograin film. The change in morphology is discussed in terms of the change in the yield of the photoelectrons generated by x rays as a function of growth. (C) 2000 American Institute of Physics. [S0003-6951(00)01815-5]. C1 Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RP Ma, Q (reprint author), Argonne Natl Lab, Adv Photon Source, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Rosenberg, Richard/K-3442-2012 NR 15 TC 32 Z9 32 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 10 PY 2000 VL 76 IS 15 BP 2014 EP 2016 DI 10.1063/1.126239 PG 3 WC Physics, Applied SC Physics GA 301ER UT WOS:000086296200016 ER PT J AU Siegal, MP Provencio, PN Tallant, DR Simpson, RL Kleinsorge, B Milne, WI AF Siegal, MP Provencio, PN Tallant, DR Simpson, RL Kleinsorge, B Milne, WI TI Bonding topologies in diamondlike amorphous-carbon films SO APPLIED PHYSICS LETTERS LA English DT Article ID PULSED-LASER DEPOSITION; ION ENERGY; EMISSION; GROWTH; ARC AB The carbon ion energy used during filtered cathodic vacuum arc deposition determines the bonding topologies of amorphous-carbon (a-C) films. Regions of relatively low density occur near the substrate/film and film/surface interfaces; their thicknesses increase with deposition energy. The ion subplantation growth results in mass density gradients in the bulk portion of a-C in the growth direction; density decreases with distance from the substrate for films grown using ion energies < 60 eV and increases for films grown using ion energies > 160 eV. Films grown between these energies are the most diamondlike with relatively uniform bulk density and the highest optical transparencies. Bonding topologies evolve with increasing growth energy consistent with the propagation of subplanted carbon ions inducing a partial transformation of sigma- to pi-bonded carbon atoms. (C) 2000 American Institute of Physics. [S0003-6951(00)05615-1]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Cambridge, Dept Engn, Cambridge CB2 1PZ, England. RP Siegal, MP (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 20 TC 31 Z9 31 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 10 PY 2000 VL 76 IS 15 BP 2047 EP 2049 DI 10.1063/1.126250 PG 3 WC Physics, Applied SC Physics GA 301ER UT WOS:000086296200027 ER PT J AU List, EJW Kim, CH Shinar, J Pogantsch, A Leising, G Graupner, W AF List, EJW Kim, CH Shinar, J Pogantsch, A Leising, G Graupner, W TI Charged defects in highly emissive organic wide-band-gap semiconductors SO APPLIED PHYSICS LETTERS LA English DT Article ID LIGHT-EMITTING-DIODES; CONJUGATED POLYMERS; LADDER POLYMER AB A combined photoluminescence (PL) -detected magnetic-resonance (PLDMR) and thermally stimulated current (TSC) study of defects in wide-band-gap para-phenylene-type semiconductors is described. As TSC probes the density of mobile charge carriers after detrapping and PLDMR reveals the influence of trapped charges on the PL, their combination yields the concentration of traps, their energetic position, and their contribution to PL quenching. The reported trap densities, which are 2 x 10(16) for the polymer and 1 x 10(14) cm(-3), for the oligomer, are the lowest reported for para-phenylene-type materials. (C) 2000 American Institute of Physics. [S0003-6951(00)03615-9]. C1 Graz Tech Univ, Inst Festkorperphys, A-8010 Graz, Austria. Iowa State Univ, Ames Lab, US DOE, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. Virginia Tech, Dept Phys, Blacksburg, VA 24060 USA. RP List, EJW (reprint author), Graz Tech Univ, Inst Festkorperphys, Petersgasse 16, A-8010 Graz, Austria. RI List-Kratochvil, Emil/M-5312-2013 NR 15 TC 38 Z9 38 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 10 PY 2000 VL 76 IS 15 BP 2083 EP 2085 DI 10.1063/1.126262 PG 3 WC Physics, Applied SC Physics GA 301ER UT WOS:000086296200039 ER PT J AU Brinkmann, W Laurent-Muehleisen, SA Voges, W Siebert, J Becker, RH Brotherton, MS White, RL Gregg, MD AF Brinkmann, W Laurent-Muehleisen, SA Voges, W Siebert, J Becker, RH Brotherton, MS White, RL Gregg, MD TI Radio and X-ray bright AGN: the ROSAT-FIRST correlation SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : active; galaxies : quasars : general; X-rays : general; radio continuum : general ID ACTIVE GALACTIC NUCLEI; BL-LACERTAE OBJECTS; ALL-SKY SURVEY; QUIET QUASARS; GALAXIES; CATALOG; SPECTRA; SAMPLE; IDENTIFICATIONS; QSOS AB We present the results of a correlation of the ROSAT All-Sky Survey with the April 1997 release of the VLA 20cm FIRST catalogue. We focus our analysis on the 843 X-ray sources which have unique radio counterparts. The majority of these objects (84%) have optical counterparts on the POSS 1 plates. Approximately 30% have been previously classified and we obtain new spectroscopic classifications for 85 sources by comparison with the ongoing FIRST Bright Quasar Survey and 106 additional sources from our own new spectroscopic data. Approximately 51% of the sources are presently classified, and the majority of the unclassified objects are optically faint. The newly classified sources are generally radio weak, exhibiting properties intermediate with previous samples of radio- and Xray-selected AGN. This also holds for the subsample of 71 BL Lacs which includes many intermediate objects. The 146 quasars show no evidence for a bimodal distribution in their radio-loudness parameter, indicating that the supposed division between radio-quiet and radio-loud AGN may not be real. The X-ray and radio luminosities are correlated over two decades in radio luminosity, spanning the radio-loud and radio-quiet regimes, with radio-quiet quasars showing a linear correlation between the two luminosities. Many of the sources show peculiar or unusual properties which call for more detailed follow-up observations. We also give the X-ray and radio data for the 518 X-ray sources for which more than one radio object is found. Because of the difficulties inherent in identifying optical counterparts to these complex sources, we do not consider these data in the current analysis(1). C1 Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. Univ Calif Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94450 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. RP Brinkmann, W (reprint author), Max Planck Inst Extraterr Phys, Giessenbachstr, D-85740 Garching, Germany. EM wpb@mpe.mpg.de RI White, Richard/A-8143-2012 NR 57 TC 101 Z9 101 U1 0 U2 1 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 APR 10 PY 2000 VL 356 IS 2 BP 445 EP 462 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 316RW UT WOS:000087182700012 ER PT J AU Dijkwel, PA Mesner, LS Levenson, VV d'Anna, J Hamlin, JL AF Dijkwel, PA Mesner, LS Levenson, VV d'Anna, J Hamlin, JL TI Dispersive initiation of replication in the Chinese hamster rhodopsin locus SO EXPERIMENTAL CELL RESEARCH LA English DT Article DE replication; origin; mammalian; CHO; initiation ID DIHYDROFOLATE-REDUCTASE DOMAIN; BIDIRECTIONAL DNA-REPLICATION; AMINO-ACID MIMOSINE; CHO CELLS; AUTONOMOUS REPLICATION; S-CEREVISIAE; START SITES; OVARY CELLS; GENE DOMAIN; ORIGIN AB Several higher eukaryotic replication origins appear to be composed of broad zones of potential nascent strand start sites, while others are more circumscribed, resembling those of yeast, bacteria, and viruses. The most delocalized origin identified so far is similar to 55 kb in length and lies between the convergently transcribed dihydrofolate reductase (DHFR) and the 2BE2121 genes on chromosome 2 in the Chinese hamster genome. In some of our studies, we have utilized the rhodopsin origin as an early replicating internal standard for assessing the effects of deleting various parts of the DHFR locus on DHFR origin activity. However, it had not been previously established that the rhodopsin locus was located at a site far enough away to be immune to such deletions, nor had the mechanism of initiation at this origin been characterized. In the present study, are have localized the rhodopsin domain to a pair of small metacentric chromosomes and have used neutral/neutral 2-D gel replicon mapping to show that initiation in this origin is also highly delocalized, encompassing a region more than 50 kb in length that includes the nontranscribed rhodopsin gene itself. The initiation zone is flanked at least on one end by an actively transcribed gene that does not support initiation. Thus, the DHFR and rhodopsin origins belong to a class of complex, polydisperse origins that appears to be unique to higher eukaryotic cells. (C) 2000 Academic Press. C1 Univ Virginia, Sch Med, Dept Biochem & Mol Genet, Charlottesville, VA 22908 USA. Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. RP Dijkwel, PA (reprint author), Univ Virginia, Sch Med, Dept Biochem & Mol Genet, Box 440,Jordan MEB, Charlottesville, VA 22908 USA. NR 47 TC 30 Z9 31 U1 0 U2 0 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0014-4827 J9 EXP CELL RES JI Exp. Cell Res. PD APR 10 PY 2000 VL 256 IS 1 BP 150 EP 157 DI 10.1006/excr.2000.4809 PG 8 WC Oncology; Cell Biology SC Oncology; Cell Biology GA 304HB UT WOS:000086476700018 PM 10739662 ER PT J AU De Boer, J Evslin, J Halpern, MB Wang, JE AF De Boer, J Evslin, J Halpern, MB Wang, JE TI New duality transformations in orbifold theory SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article ID CONFORMAL FIELD-THEORY; PION-QUARK MODEL; CYCLIC PERMUTATIONS; AFFINE-G; 2 FACES; ALGEBRA; STRINGS; CONSTRUCTION; CHARACTERS; PRODUCTS AB We find new duality transformations which allow us to construct the stress tensors of all the twisted sectors of any orbifold A(H)/H, where A(H) is the set of all current-algebraic conformal field theories with a finite symmetry group H subset of Aut(g). The permutation orbifolds with H = Z(lambda) and H = S-3 are worked out in full as illustrations but the general formalism includes both simple and semisimple g. The motivation for this development is the recently-discovered orbifold Virasoro master equation, whose solutions are identified by the duality transformations as sectors of the permutation orbifolds A(D-lambda)/Z(lambda). C1 Univ Utrecht, Spinoza Inst, NL-3584 CE Utrecht, Netherlands. Leiden Univ, Inst Lorentz Theoret Phys, NL-2300 RA Leiden, Netherlands. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RP De Boer, J (reprint author), Univ Utrecht, Spinoza Inst, Leuvenlaan 4, NL-3584 CE Utrecht, Netherlands. NR 39 TC 25 Z9 25 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 APR 10 PY 2000 VL 15 IS 9 BP 1297 EP 1344 DI 10.1142/S0217751X00000586 PG 48 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 314LB UT WOS:000087056300002 ER PT J AU Brown, DJ Stringfield, RM AF Brown, DJ Stringfield, RM TI Iterative methods applied to matrix equations found in calculating spheroidal functions SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE spheroidal wave functions; iterative methods for linear systems; eigenvalue problems AB We look at iterative methods for solving matrix equations, particularly those matrices with small entries. Iterative methods aid computational stability by relying on the topological structure of Banach or Hilbert spaces rather than depending on a calculation's numerical precision. When applicable, they are also quicker than Gaussian elimination. As an example, we use these methods to tabulate the expansion of periodic spheroidal functions in associated Legendre functions, given arbitrary values of the parameters appearing in its defining differential equation. These functions appear in solutions to 3-D Helmholtz equations in oblate and prolate spheroidal coordinates as well as a 1-D Schrodinger equation. (C) 2000 Academic Press. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Brown, DJ (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 18 TC 0 Z9 0 U1 0 U2 0 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD APR 10 PY 2000 VL 159 IS 2 BP 329 EP 343 DI 10.1006/jcph.2000.6448 PG 15 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 303BM UT WOS:000086401000011 ER PT J AU Frink, LJD Salinger, AG AF Frink, LJD Salinger, AG TI Two- and three-dimensional nonlocal density functional theory for inhomogeneous fluids I. Algorithms and parallelization SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE inhomogeneous fluids; solvation; density functional theory; molecular theory; parallelization; finite element ID HARD-SPHERE FLUID; ADSORPTION; INTERFACE; FORCES; PORES; GAS AB Fluids adsorbed near surfaces, near macromolecules, and in porous materials are inhomogeneous, exhibiting spatially varying density distributions. This inhomogeneity in the fluid plays an important role in controlling a wide variety of complex physical phenomena including wetting, self-assembly, corrosion, and molecular recognition. One of the key methods for studying the properties of inhomogeneous fluids in simple geometries has been density functional theory (DFT). However, there has been a conspicuous lack of calculations in complex two- and three-dimensional geometries, The computational difficulty arises from the need to perform nested integrals that are due to nonlocal terms in the free energy functional. These integral equations are expensive both in evaluation time and in memory requirements; however, the expense can be mitigated by intelligent algorithms and the use of parallel computers This paper details our efforts to develop efficient numerical algorithms so that nolocal DFT calculations in complex geometries that require two or three dimensions can be performed. The success of this implementation will enable the study of solvation effects at heterogeneous surfaces, in zeolites, in solvated (bio)polymers, and in colloidal suspensions. (C) 2000 Academic Press. C1 Sandia Natl Labs, Computat Biol & Mat Technol Dept, Albuquerque, NM 87185 USA. Sandia Natl Labs, Parallel Computat Sci Dept, Albuquerque, NM 87185 USA. RP Frink, LJD (reprint author), Sandia Natl Labs, Computat Biol & Mat Technol Dept, POB 5800, Albuquerque, NM 87185 USA. NR 24 TC 39 Z9 39 U1 0 U2 6 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD APR 10 PY 2000 VL 159 IS 2 BP 407 EP 424 PG 18 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 303BM UT WOS:000086401000014 ER PT J AU Frink, LJD Salinger, AG AF Frink, LJD Salinger, AG TI Two- and three-dimensional nonlocal density functional theory for inhomogeneous fluids II. Solvated polymers as a benchmark problem SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE density functional theory; solvation force; colloidal stability; DNA; polymer; liquid crystals ID MONTE-CARLO; FORCES AB In a previous companion paper, we presented the details of our algorithms for performing nonlocal density functional theory calculations in complex two- and three-dimensional geometries. We discussed scaling and parallelization, but did not discuss other issues of performance. In this paper, we detail the precision of our methods with respect to changes in the mesh spacing. This is a complex issue because given a Cartesian mesh, changes in mesh spacing will result in changes in surface geometry. We discuss these issues using a series of rigid solvated polymer models including square rod polymers, cylindrical polymers, and bead-chain polymers. In comparing the results of the various models, it becomes clear that surface curvature or roughness plays an important role in determining the strength of structural solvation forces between interacting solvated polymers. The results in this paper serve as benchmarks for future application of these algorithms to complex fluid systems. (C) 2000 Academic Press. C1 Sandia Natl Labs, Computat Biol & Mat Technol Dept, Albuquerque, NM 87185 USA. Sandia Natl Labs, Parallel Computat Sci Dept, Albuquerque, NM 87185 USA. RP Frink, LJD (reprint author), Sandia Natl Labs, Computat Biol & Mat Technol Dept, POB 5800, Albuquerque, NM 87185 USA. NR 17 TC 22 Z9 22 U1 0 U2 1 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD APR 10 PY 2000 VL 159 IS 2 BP 425 EP 439 PG 15 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 303BM UT WOS:000086401000015 ER PT J AU Turner, L AF Turner, L TI Using helicity to characterize homogeneous and inhomogeneous turbulent dynamics SO JOURNAL OF FLUID MECHANICS LA English DT Article ID ISOTROPIC TURBULENCE; ROTATION; MODEL; FLOWS AB The ability of the helicity decomposition to describe compactly the dynamics of three-dimensional incompressible fluids is invoked to obtain new descriptions of both homogeneous and inhomogeneous turbulence. We first use this decomposition to derive four coupled nonlinear equations that describe an arbitrary three-dimensional turbulence, whether anisotropic and/or non-mirror-symmetric. We then use the decomposition to treat the inhomogeneous turbulence of a channel flow bounded by two parallel free-slip boundaries with almost the ease with which the homogeneous case has heretofore received treatment. However, this ease arises from the foundation of a random-phase hypothesis, which we introduce and motivate, that supersedes the translational invariance of a turbulence that is hypothesized to be homogeneous. For the description of this channel turbulence, we find that the three-dimensional modes and the two-dimensional modes having wave vectors parallel to the boundaries each couple precisely as in a homogeneous turbulence of the corresponding dimension. The anisotropy and inhomogeneity is in large part a feature incorporated into the solenoidal basis vectors used to describe an arbitrary solenoidal free-slip flow within the channel. We invoke the random-phase hypothesis, a feature of the dynamics, with closures, such as Kraichnan's direct-interaction approximation and his test-held model, in addition to the one most utilized in this manuscript, the eddy-damped quasi-normal Markovian (EDQNM) closure. C1 Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Turner, L (reprint author), Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 34 TC 11 Z9 11 U1 0 U2 2 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 APR 10 PY 2000 VL 408 BP 205 EP 238 DI 10.1017/S002211209900779X PG 34 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 308VM UT WOS:000086733600008 ER PT J AU Huang, D Lyo, SK AF Huang, D Lyo, SK TI Suppression of impurity and interface-roughness back-scattering in double quantum wires: theory beyond the Born approximation SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article AB The effect of higher-order corrections to the Born approximation is studied for the previously obtained giant conductance enhancement in tunnel-coupled double quantum wires in a magnetic field by including both impurity and interface-roughness scattering. The enhancement is caused by an abrupt suppression of back-scattering of electrons which occurs when the chemical potential is in the anticrossing gap of the ground tunnel-split doubler. The calculated conductance enhancement is large, and the relative higher-order correction to the enhancement is found to be significant for long-range scattering potentials. However, this relative higher-order correction will be reduced as the range of scattering potentials becomes small. The correction depends on various effects, such as the magnetic field, electron and impurity densities, impurity positions, symmetric and asymmetric doping profiles, centre barrier thickness, and degree of interface roughness. C1 USAF, Res Lab, AFRL, VSSS, Kirtland AFB, NM 87117 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Huang, D (reprint author), USAF, Res Lab, AFRL, VSSS, Kirtland AFB, NM 87117 USA. NR 9 TC 11 Z9 11 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD APR 10 PY 2000 VL 12 IS 14 BP 3383 EP 3396 DI 10.1088/0953-8984/12/14/314 PG 14 WC Physics, Condensed Matter SC Physics GA 308FZ UT WOS:000086701000014 ER PT J AU La Commara, M del Campo, JG D'Onofrio, A Gadea, A Glogowski, M Jarillo-Herrero, P Belcari, N Borcea, R de Angelis, G Fahlander, C Gorska, M Grawe, H Hellstrom, M Kirchner, R Rejmund, M Roca, V Roeckl, E Romano, M Rykaczewski, K Schmidt, K Terrasi, F AF La Commara, M del Campo, JG D'Onofrio, A Gadea, A Glogowski, M Jarillo-Herrero, P Belcari, N Borcea, R de Angelis, G Fahlander, C Gorska, M Grawe, H Hellstrom, M Kirchner, R Rejmund, M Roca, V Roeckl, E Romano, M Rykaczewski, K Schmidt, K Terrasi, F TI Production of very neutron-deficient isotopes near Sn-100 via reactions involving light-particle and cluster emission SO NUCLEAR PHYSICS A LA English DT Article DE Sn-100; production cross sections; cluster emission; isotope separation on-line; beta-delayed radiation ID EXCITED-STATES; SEPARATOR AB The production of very neutron-deficient isotopes near Sn-100 has been investigated by using on-line mass separation of evaporation residues produced by heavy-ion induced complete-fusion reactions. We measured the cross sections for Cd-99, In-100, Sn-101 and In-102 via Ni-58 + 58Ni fusion reactions followed by cluster emission, and via Ni-58 + Cr-50 fusion reactions accompanied by evaporation of protons, neutrons or cu particles. Both types of reactions yield similar cross sections for the production of exotic nuclei near Sn-100. The data are discussed in comparison with results obtained from statistical-model calculations. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Gesell Schwerionenforsch GmbH, D-64291 Darmstadt, Germany. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Univ Naples 2, Dipartimento Sci Ambientali, I-81100 Caserta, Italy. Complesso Univ Monte S Angelo, Ist Nazl Fis Nucl, Sez Napoli, I-80126 Naples, Italy. Univ Warsaw, Inst Expt Phys, PL-00681 Warsaw, Poland. Univ Valencia, E-46100 Burjassot, Valencia, Spain. Univ Lund, Div Cosm & Subatom Phys, S-22100 Lund, Sweden. CSNSM Orsay, F-91405 Orsay, France. Univ Naples Federico II, Dipartimento Sci Fisiche, I-80126 Naples, Italy. RP La Commara, M (reprint author), Gesell Schwerionenforsch GmbH, D-64291 Darmstadt, Germany. RI Gadea, Andres/L-8529-2014; Belcari, Nicola/M-4811-2015; OI Gadea, Andres/0000-0002-4233-1970; Belcari, Nicola/0000-0002-7648-9450; Terrasi, Filippo/0000-0001-5641-8973 NR 11 TC 34 Z9 34 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 APR 10 PY 2000 VL 669 IS 1-2 BP 43 EP 50 DI 10.1016/S0375-9474(99)00814-3 PG 8 WC Physics, Nuclear SC Physics GA 299PD UT WOS:000086206300004 ER PT J AU Schaffner-Bielich, J Koch, V Effenberger, M AF Schaffner-Bielich, J Koch, V Effenberger, M TI Medium modified cross sections, temperature and finite momentum effects for antikaon production in heavy-ion collisions SO NUCLEAR PHYSICS A LA English DT Article ID NUCLEUS-NUCLEUS COLLISIONS; KAON PRODUCTION; DENSE NUCLEAR; SIS ENERGIES; MATTER; CONDENSATION; LAMBDA(1405); POTENTIALS; ABSORPTION; DYNAMICS AB The medium modifications of antikaons in dense matter are studied in a coupled channel calculation for scenarios more closely related to the environment encountered in heavy-ion collisions. We find that the optical potential of the antikaons turns repulsive or is drastically reduced for finite momenta or finite temperature. Hence, the antikaon mass does not decrease substantially in heavy-ion collisions to provide an explanation for the observed antikaon production rates at threshold. We demonstrate that the in-medium production cross section of antikaons via pions and Sigma hyperons is remarkably enhanced up to an order of magnitude. The effect of in medium correction on the resulting kaon spectra is studied within a transport model, We find that both in medium correction lead to about the same enhancement of the spectrum. However, once the temperature dependence is taken into account no enhancement is found, (C) 2000 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, RIKEN BNL Res Ctr, Upton, NY 11973 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Univ Giessen, Inst Theoret Phys, D-35392 Giessen, Germany. RP Schaffner-Bielich, J (reprint author), Brookhaven Natl Lab, RIKEN BNL Res Ctr, Upton, NY 11973 USA. NR 38 TC 122 Z9 123 U1 1 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 APR 10 PY 2000 VL 669 IS 1-2 BP 153 EP 172 DI 10.1016/S0375-9474(99)00690-9 PG 20 WC Physics, Nuclear SC Physics GA 299PD UT WOS:000086206300011 ER PT J AU Cohen, JH Leitko, CE Long, RC AF Cohen, JH Leitko, CE Long, RC TI Slimhole drilling system doubles penetration rates SO OIL & GAS JOURNAL LA English DT Article C1 Maurer Engn Inc, Houston, TX USA. US Dept Energy, Natl Energy Technol Lab, Morgantown, WV USA. RP Cohen, JH (reprint author), Maurer Engn Inc, Houston, TX USA. NR 3 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 APR 10 PY 2000 VL 98 IS 15 BP 67 EP 69 PG 3 WC Energy & Fuels; Engineering, Petroleum SC Energy & Fuels; Engineering GA 304NN UT WOS:000086490500014 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 Kaplan, DM Kaufman, SB Koetke, DD McGaughey, PL Moss, JM Mueller, BA Papavassiliou, V Peng, JC Petitt, G Reimer, PE Sadler, ME Sondheim, WE Stankus, PW Towell, RS Tribble, RE Vasiliev, MA Webb, JC Willis, JL Young, GR 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 Kaplan, DM Kaufman, SB Koetke, DD McGaughey, PL Moss, JM Mueller, BA Papavassiliou, V Peng, JC Petitt, G Reimer, PE Sadler, ME Sondheim, WE Stankus, PW Towell, RS Tribble, RE Vasiliev, MA Webb, JC Willis, JL Young, GR CA FNAL E866 NuSea Collaboration TI Measurement of differences between J/psi and psi ' suppression in p-A collisions SO PHYSICAL REVIEW LETTERS LA English DT Article ID NUCLEAR-DEPENDENCE; MONTE-CARLO; 800 GEV/C; PROTONS AB Measurements of the suppression of the yield per nucleon of J/psi and psi' production for 800 GeV/c protons incident on heavy nuclear targets, relative to light nuclear targets, have been made with very broad. coverage in x(F) and p(T). The observed suppression is smallest at x(F) values of 0.25 and below, and increases at larger values of x(F). It is also strongest at small p(T). Substantial differences between psi' and J/psi production are observed for the first time in p-A collisions. The suppression for psi' production is stronger than that for J/psi for x(F) near zero, but becomes comparable to chat for J/psi for x(F) > 0.6. C1 Abilene Christian Univ, Abilene, TX 79699 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Georgia State Univ, Atlanta, GA 30303 USA. IIT, Chicago, IL 60616 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. New Mexico State Univ, Las Cruces, NM 88003 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Texas A&M Univ, College Stn, TX 77843 USA. Valparaiso Univ, Valparaiso, IN 46383 USA. RP Abilene Christian Univ, Abilene, TX 79699 USA. RI Reimer, Paul/E-2223-2013 NR 22 TC 219 Z9 223 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 APR 10 PY 2000 VL 84 IS 15 BP 3256 EP 3260 DI 10.1103/PhysRevLett.84.3256 PG 5 WC Physics, Multidisciplinary SC Physics GA 303DA UT WOS:000086404500011 ER PT J AU Schaffner-Bielich, J AF Schaffner-Bielich, J TI Effective restoration of the U-A(1) symmetry in the SU(3) linear sigma model SO PHYSICAL REVIEW LETTERS LA English DT Article ID FINITE-TEMPERATURE QCD; LATTICE QCD; CHIRAL-SYMMETRY; GOLDSTONE BOSON; MESON; THERMODYNAMICS; CHROMODYNAMICS; SCATTERING; QUARKS; ZERO AB The effective restoration of the chiral U-A(1) symmetry in strong interactions is studied using the linear chiral SU(3) X SU(3) model at finite temperatures. We find that the disappearance of the chiral anomaly causes a considerable change in the meson mass spectrum. We propose several signals for detecting this chiral phase in ultrarelativistic heavy-ion collisions: The eta/pi(0) no ratio is enhanced by an order of magnitude, the a(0)(K) over bar is suppressed in the K mass spectrum, and the scalar kappa meson appears as a peak just below the K*(892) in the invariant pi K mass spectrum. C1 RIKEN, BNL, Res Ctr, Brookhaven Natl Lab, Upton, NY 11973 USA. RP Schaffner-Bielich, J (reprint author), RIKEN, BNL, Res Ctr, Brookhaven Natl Lab, Upton, NY 11973 USA. NR 46 TC 42 Z9 42 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 APR 10 PY 2000 VL 84 IS 15 BP 3261 EP 3264 DI 10.1103/PhysRevLett.84.3261 PG 4 WC Physics, Multidisciplinary SC Physics GA 303DA UT WOS:000086404500012 ER PT J AU Gao, J Anderson, BD Aniol, KA Auerbach, L Baker, FT Berthot, J Bertozzi, W Bertin, PY Bimbot, L Boeglin, WU Brash, EJ Breton, V Breuer, H Burtin, E Calarco, JR Cardman, L Cates, GD Cavata, C Chang, CC Chen, JP Cisbani, E Dale, DS De Leo, R Deur, A Diederich, B Djawotho, P Domingo, J Doyle, B Ducret, JE Epstein, MB Ewell, LA Finn, JM Fissum, KG Fonvieille, H Frois, B Frullani, S Garibaldi, F Gasparian, A Gilad, S Gilman, R Glamazdin, A Glashausser, C Gomez, J Gorbenko, V Gorringe, T Griffioen, K Hersman, FW Holmes, R Holtrop, M d'Hose, N Howell, C Huber, GM Hyde-Wright, CE Iodice, M de Jager, CW Jaminion, S Jones, MK Joo, K Jutier, C Kahl, W Kato, S Kelly, JJ Kerhoas, S Khandaker, M Khayat, M Kino, K Korsh, W Kramer, L Kumar, KS Kumbartzki, G Laveissiere, G Leone, A LeRose, JJ Levchuk, L Liang, M Lindgren, RA Liyanage, N Lolos, GJ Lourie, RW Madey, R Maeda, K Malov, S Manley, DM Margaziotis, DJ Markowitz, P Martino, J McCarthy, JS McCormick, K McIntyre, J van der Meer, RLJ Meziani, ZE Michaels, R Mougey, J Nanda, S Neyret, D Offermann, EAJM Papandreou, Z Perdrisat, CF Perrino, R Petratos, GG Platchkov, S Pomatsalyuk, R Prout, DL Punjabi, VA Pussieux, T Quemener, G Ransome, RD Ravel, O Roblin, Y Roche, R Rowntree, D Rutledge, GA Rutt, PM Saha, A Saito, T Sarty, AJ Serdarevic-Offermann, A Smith, TP Soldi, A Sorokin, P Souder, P Suleiman, R Templon, JA Terasawa, T Todor, L Tsubota, H Ueno, H Ulmer, PE Urciuoli, GM Vernin, P van Verst, S Vlahovic, B Voskanyan, H Watson, JW Weinstein, LB Wijesooriya, K Wilson, R Wojtsekhowski, B Zainea, DG Zeps, V Zhao, J Zhou, ZL AF Gao, J Anderson, BD Aniol, KA Auerbach, L Baker, FT Berthot, J Bertozzi, W Bertin, PY Bimbot, L Boeglin, WU Brash, EJ Breton, V Breuer, H Burtin, E Calarco, JR Cardman, L Cates, GD Cavata, C Chang, CC Chen, JP Cisbani, E Dale, DS De Leo, R Deur, A Diederich, B Djawotho, P Domingo, J Doyle, B Ducret, JE Epstein, MB Ewell, LA Finn, JM Fissum, KG Fonvieille, H Frois, B Frullani, S Garibaldi, F Gasparian, A Gilad, S Gilman, R Glamazdin, A Glashausser, C Gomez, J Gorbenko, V Gorringe, T Griffioen, K Hersman, FW Holmes, R Holtrop, M d'Hose, N Howell, C Huber, GM Hyde-Wright, CE Iodice, M de Jager, CW Jaminion, S Jones, MK Joo, K Jutier, C Kahl, W Kato, S Kelly, JJ Kerhoas, S Khandaker, M Khayat, M Kino, K Korsh, W Kramer, L Kumar, KS Kumbartzki, G Laveissiere, G Leone, A LeRose, JJ Levchuk, L Liang, M Lindgren, RA Liyanage, N Lolos, GJ Lourie, RW Madey, R Maeda, K Malov, S Manley, DM Margaziotis, DJ Markowitz, P Martino, J McCarthy, JS McCormick, K McIntyre, J van der Meer, RLJ Meziani, ZE Michaels, R Mougey, J Nanda, S Neyret, D Offermann, EAJM Papandreou, Z Perdrisat, CF Perrino, R Petratos, GG Platchkov, S Pomatsalyuk, R Prout, DL Punjabi, VA Pussieux, T Quemener, G Ransome, RD Ravel, O Roblin, Y Roche, R Rowntree, D Rutledge, GA Rutt, PM Saha, A Saito, T Sarty, AJ Serdarevic-Offermann, A Smith, TP Soldi, A Sorokin, P Souder, P Suleiman, R Templon, JA Terasawa, T Todor, L Tsubota, H Ueno, H Ulmer, PE Urciuoli, GM Vernin, P van Verst, S Vlahovic, B Voskanyan, H Watson, JW Weinstein, LB Wijesooriya, K Wilson, R Wojtsekhowski, B Zainea, DG Zeps, V Zhao, J Zhou, ZL CA Jefferson Lab Hall A Collaboration TI Dynamical relativistic effects in quasielastic 1p-shell proton knockout from O-16 SO PHYSICAL REVIEW LETTERS LA English DT Article ID ELECTRON-SCATTERING; OPTICAL POTENTIALS; CROSS-SECTIONS; NUCLEI; TARGET; STATE AB We have measured the cross section for quasielastic 1p-shell proton knockout in the O-16(e,e'p) reaction at omega = 0.439 GeV and Q(2) = 0.8 (GeV/c)(2) for missing momentum P-miss less than or equal to 355 MeV/c. We have extracted the response functions RL+TT, R-T, R-LT, and the left-right asymmetry, A(LT), for the 1p(1/2) and the 1p(3/2) states. The data are well described by relativistic distorted wave impulse approximation calculations. At large P-miss, the structure observed in A(LT) indicates the existence of dynamical relativistic effects. C1 MIT, Cambridge, MA 02139 USA. Univ Blaise Pascal, IN2P3, F-63177 Clermont Ferrand, France. Calif State Univ Los Angeles, Los Angeles, CA 90032 USA. Inst Nucl Sci, F-38026 Grenoble, France. Duke Univ, Durham, NC 27706 USA. Florida Int Univ, Miami, FL 33199 USA. Florida State Univ, Tallahassee, FL 32306 USA. Univ Georgia, Athens, GA 30602 USA. Hampton Univ, Hampton, VA 23668 USA. Harvard Univ, Cambridge, MA 02138 USA. Ist Nazl Fis Nucl, Sezione Bari, I-70126 Bari, Italy. Univ Bari, I-70126 Bari, Italy. Ist Nazl Fis Nucl, Sezione Lecce, I-73100 Lecce, Italy. Ist Nazl Fis Nucl, Sez Sanita, I-00161 Rome, Italy. Ist Super Sanita, Fis Lab, I-00161 Rome, Italy. Kent State Univ, Kent, OH 44242 USA. Univ Kentucky, Lexington, KY 40506 USA. Kharkov Phys & Technol Inst, UA-310108 Kharkov, Ukraine. Univ Maryland, College Pk, MD 20742 USA. Univ New Hampshire, Durham, NH 03824 USA. Norfolk State Univ, Norfolk, VA 23504 USA. N Carolina Cent Univ, Durham, NC 27707 USA. Old Dominion Univ, Norfolk, VA 23529 USA. Inst Phys Nucl, F-91406 Orsay, France. Princeton Univ, Princeton, NJ 08544 USA. Univ Regina, Regina, SK S4S 0A2, Canada. Rutgers State Univ, Piscataway, NJ 08854 USA. CEA Saclay, F-91191 Gif Sur Yvette, France. SUNY Stony Brook, Stony Brook, NY 11794 USA. Syracuse Univ, Syracuse, NY 13244 USA. Temple Univ, Philadelphia, PA 19122 USA. Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. Tohoku Univ, Sendai, Miyagi 980, Japan. Univ Virginia, Charlottesville, VA 22901 USA. Coll William & Mary, Williamsburg, VA 23187 USA. Yamagata Univ, Yamagata 990, Japan. Yerevan Phys Inst, Yerevan 375036, Armenia. RP Gao, J (reprint author), MIT, 77 Massachusetts Ave, Cambridge, MA 02139 USA. RI Perrino, Roberto/B-4633-2010; kino, koichi/D-6173-2012; Sarty, Adam/G-2948-2014; McIntyre, Justin/P-1346-2014; CAVATA, Christian/P-6496-2015; Cisbani, Evaristo/C-9249-2011; OI Perrino, Roberto/0000-0002-5764-7337; McIntyre, Justin/0000-0002-3706-4310; Cisbani, Evaristo/0000-0002-6774-8473; Glamazdin, Alexander/0000-0002-4172-7324 NR 30 TC 61 Z9 61 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 APR 10 PY 2000 VL 84 IS 15 BP 3265 EP 3269 DI 10.1103/PhysRevLett.84.3265 PG 5 WC Physics, Multidisciplinary SC Physics GA 303DA UT WOS:000086404500013 ER PT J AU Diamant, R Huotari, S Hamalainen, K Kao, CC Deutsch, M AF Diamant, R Huotari, S Hamalainen, K Kao, CC Deutsch, M TI Evolution from threshold of a hollow atom's X-ray emission spectrum: The CuKh alpha(1,2) hypersatellites SO PHYSICAL REVIEW LETTERS LA English DT Article ID ONE-PHOTON; K-ALPHA; SYNCHROTRON-RADIATION; FLUORESCENCE YIELDS; TRANSITIONS; 2-ELECTRON; EXCITATION; SATELLITES; SHELL; IONS AB The first pure high-resolution photoexcited K(h)alpha(1,2) hypersatellite spectrum from a hollow Cu atom is measured. Its K(h)alpha(2)-K alpha(1) shift and the K(h)alpha(1,2) lines' splitting, widths, and intensity ratio are accurately determined. Such spectra are uniquely suited to study reIativistic correlation effects, transition from LS to intermediate coupling, and the Breit-Wigner interaction. The threshold energy and the spectrum's evolution with excitation energy are also measured. The roles of relativity and Breit interaction are explored by comparison with ab initio Dirac-Fock calculations. C1 Bar Ilan Univ, Dept Phys, IL-52900 Ramat Gan, Israel. Univ Helsinki, Dept Phys, FIN-00014 Helsinki, Finland. Brookhaven Natl Lab, NSLS, Upton, NY 11973 USA. RP Diamant, R (reprint author), Bar Ilan Univ, Dept Phys, IL-52900 Ramat Gan, Israel. RI Hamalainen, Keijo/A-3986-2010 OI Hamalainen, Keijo/0000-0002-9234-9810 NR 41 TC 45 Z9 45 U1 2 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 10 PY 2000 VL 84 IS 15 BP 3278 EP 3281 DI 10.1103/PhysRevLett.84.3278 PG 4 WC Physics, Multidisciplinary SC Physics GA 303DA UT WOS:000086404500016 ER PT J AU Aranson, IS Blair, D Kalatsky, VA Crabtree, GW Kowk, WK Vinokur, VM Welp, U AF Aranson, IS Blair, D Kalatsky, VA Crabtree, GW Kowk, WK Vinokur, VM Welp, U TI Electrostatically driven granular media: Phase transitions and coarsening SO PHYSICAL REVIEW LETTERS LA English DT Article ID PATTERNS; LAYERS AB We report the experimental and theoretical study of electrostatically driven granular material. We show that the charged granular medium undergoes a hysteretic phase transition from the immobile condensed state (granular solid) to a fluidized dilated state (granular gas) with a changing applied electric field. In addition we observe a spontaneous precipitation of dense clusters from the gas phase and subsequent coarsening-coagulation of these clusters. Molecular dynamics simulations show qualitative agreement with experimental results. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Aranson, IS (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Aranson, Igor/I-4060-2013; Blair, Daniel/C-7911-2017 NR 19 TC 54 Z9 54 U1 3 U2 29 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 APR 10 PY 2000 VL 84 IS 15 BP 3306 EP 3309 DI 10.1103/PhysRevLett.84.3306 PG 4 WC Physics, Multidisciplinary SC Physics GA 303DA UT WOS:000086404500023 ER PT J AU Rudakov, LI Velikovich, AL Davis, J Thornhill, JW Giuliani, JL Deeney, C AF Rudakov, LI Velikovich, AL Davis, J Thornhill, JW Giuliani, JL Deeney, C TI Buoyant magnetic flux tubes enhance radiation in Z pinches SO PHYSICAL REVIEW LETTERS LA English DT Article ID ARRAY Z-PINCH; POWER AB In numerous experiments, magnetic energy coupled to strongly radiating Z-pinch plasmas exceeds the thermalized kinetic energy, sometimes by a factor of 2-3. We demonstrate that the enhanced energy coupling may be due to the buoyancy rise, of toroidal magnetic flux tubes converging to the axis through. the unstable pinch plasma. We derive an explicit formula for the enhanced dissipation rate and apply this formula to reconsider an old problem of power balance in a steady-state Z pinch, and then to analyze a new challenge of producing K-shell 3 to 10 keV radiation in long-pulse Z-pinch implosions. C1 Adv Power Technol Inc, Washington, DC 20037 USA. USN, Res Lab, Div Plasma Phys, Radiat Hydrodynam Branch, Washington, DC 20375 USA. Sandia Natl Labs, Los Alamos, NM 87545 USA. RP Rudakov, LI (reprint author), Adv Power Technol Inc, Washington, DC 20037 USA. RI Velikovich, Alexander/B-1113-2009 NR 20 TC 60 Z9 61 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 APR 10 PY 2000 VL 84 IS 15 BP 3326 EP 3329 DI 10.1103/PhysRevLett.84.3326 PG 4 WC Physics, Multidisciplinary SC Physics GA 303DA UT WOS:000086404500028 ER PT J AU Cai, W Bulatov, VV Justo, JF Argon, AS Yip, S AF Cai, W Bulatov, VV Justo, JF Argon, AS Yip, S TI Intrinsic mobility of a dissociated Dislocation in silicon SO PHYSICAL REVIEW LETTERS LA English DT Article ID 90-DEGREES PARTIAL DISLOCATION; PEIERLS STRESS; KINKS AB Dislocation velocities in silicon in the experimental range of temperature and stress are studied a priori by combining a mechanistic treatment of elementary kink processes with activation energies obtained by atomistic calculations. Pronounced effects of intrinsic coupling of the dissociated partial dislocations are captured in kinetic Monte Carlo simulations, which are consistent with observed velocity variations with applied stress. As a result, the nature of "weak obstacles" to kink propagation, a long-standing postulate in previous data interpretation, is clarified. A striking new effect is predicted and offered for experimental verification when dislocation velocity shows nonmonotonic oscillatory behavior with increasing stress. C1 MIT, Cambridge, MA 02139 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Sao Paulo, Inst Fis, BR-05315970 Sao Paulo, Brazil. RP Cai, W (reprint author), MIT, 77 Massachusetts Ave, Cambridge, MA 02139 USA. OI Cai, Wei/0000-0001-5919-8734 NR 22 TC 52 Z9 53 U1 1 U2 6 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 APR 10 PY 2000 VL 84 IS 15 BP 3346 EP 3349 DI 10.1103/PhysRevLett.84.3346 PG 4 WC Physics, Multidisciplinary SC Physics GA 303DA UT WOS:000086404500033 ER PT J AU Herman, GS Sievers, MR Gao, Y AF Herman, GS Sievers, MR Gao, Y TI Structure determination of the two-domain (1 x 4) anatase TiO2(001) surface SO PHYSICAL REVIEW LETTERS LA English DT Article ID TIO2; TIO2(110); GROWTH; WATER; FILMS; MICROSCOPY; RUTILE AB The reconstructed anatase TiO2(001) surface has been investigated by low-energy electron diffraction (LEED), x-ray photoelectron spectroscopy (XPS), and angle-resolved mass spectroscopy of recoiled ions (AR-MSRI). Prior investigations have observed or considered only a (1 x 1) unreconstructed termination for this surface with no detailed structural analysis. Our LEED results indicate a previously unobserved two-domain (1 x 4) reconstruction after sputtering and annealing the (I x 1) surface. The XPS data for this reconstruction indicate the presence of only Ti4+. Simulations of the AR-MSRI experimental data indicate a best fit for a microfaceted surface, revealing both. (103) and ((1) over bar 03) surface planes. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Herman, GS (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, POB 999,MSIN K8-93, Richland, WA 99352 USA. NR 26 TC 140 Z9 141 U1 8 U2 48 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 APR 10 PY 2000 VL 84 IS 15 BP 3354 EP 3357 DI 10.1103/PhysRevLett.84.3354 PG 4 WC Physics, Multidisciplinary SC Physics GA 303DA UT WOS:000086404500035 ER PT J AU Benedek, R Alavi, A Seidman, DN Yang, LH Muller, DA Woodward, C AF Benedek, R Alavi, A Seidman, DN Yang, LH Muller, DA Woodward, C TI First principles simulation of a ceramic/metal interface with misfit SO PHYSICAL REVIEW LETTERS LA English DT Article ID HETEROPHASE INTERFACES AB The relaxed atomic structure of a model ceramic/metal interface, (222)MgO/Cu, is simulated, including lattice: constant mismatch, using first principles local-density functional Cheery plane wave pseudopotential methods. The 399-atom computational unit. cell contains 36 O and 49 Cu atoms, per layer in accordance with the 7/6 ratio of MgO to Cu lattice constants. The atomic layers on both sides of the interface warp to optimize the local bonding. The interface: adhesive energy is calculated. The interface electronic structure is found to vary appreciably with the local environment. C1 Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. Queens Univ Belfast, Sch Math & Phys, Belfast BT7 1NN, Antrim, North Ireland. Univ Calif Lawrence Livermore Natl Lab, Condensed Matter Phys Div, Livermore, CA 94551 USA. Lucent Technol, Murray Hill, NJ 07974 USA. USAF, Res Lab, Mat & Mfg Directorate, Dayton, OH 45433 USA. Universal Energy Syst Inc, Mat Res Div, Dayton, OH 45432 USA. RP Benedek, R (reprint author), Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. RI Seidman, David/B-6697-2009; Muller, David/A-7745-2010 OI Muller, David/0000-0003-4129-0473 NR 18 TC 76 Z9 76 U1 3 U2 25 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 APR 10 PY 2000 VL 84 IS 15 BP 3362 EP 3365 DI 10.1103/PhysRevLett.84.3362 PG 4 WC Physics, Multidisciplinary SC Physics GA 303DA UT WOS:000086404500037 ER PT J AU Tignon, J Hasche, T Chemla, DS Schneider, HC Jahnke, F Koch, SW AF Tignon, J Hasche, T Chemla, DS Schneider, HC Jahnke, F Koch, SW TI Unified picture of polariton propagation in bulk GaAs semiconductors SO PHYSICAL REVIEW LETTERS LA English DT Article ID ADDITIONAL BOUNDARY-CONDITIONS; EXCITON-POLARITON; QUANTUM-WELLS; THIN-LAYERS; HALF-SPACE; QUANTIZATION; DYNAMICS; BEATS AB High-resolution amplitude and phase linear spectroscopy of high-quality bulk GaAs are reported. The detailed structure of the observed full complex transmission is consistently explained by polariton effects on the basis of microscopic calculations. The coupled equations for the excitonic polarization and the light field in the slab configuration are evaluated using appropriate boundary conditions for the electro-magnetic field and the excitonic wave function without reference to additional boundary conditions For the macroscopic polarization. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Marburg, Dept Phys, D-35032 Marburg, Germany. Univ Marburg, Ctr Mat Sci, D-35032 Marburg, Germany. Ecole Normale Super, LPMC, F-75231 Paris 05, France. RP Tignon, J (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Schneider, Hans Christian/B-9450-2009 OI Schneider, Hans Christian/0000-0001-7656-4919 NR 39 TC 28 Z9 29 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 APR 10 PY 2000 VL 84 IS 15 BP 3382 EP 3385 DI 10.1103/PhysRevLett.84.3382 PG 4 WC Physics, Multidisciplinary SC Physics GA 303DA UT WOS:000086404500042 ER PT J AU Gaulin, BD Lumsden, MD Kremer, RK Lumsden, MA Dabkowska, H AF Gaulin, BD Lumsden, MD Kremer, RK Lumsden, MA Dabkowska, H TI Two dimensional ordering and fluctuations in alpha '-NaV2O5 SO PHYSICAL REVIEW LETTERS LA English DT Article ID SPIN-PEIERLS TRANSITION; NEUTRON-SCATTERING; COMPOUND ALPHA'-NAV2O5; X-RAY; CUGEO3; NAV2O5; MODEL; LADDER AB X-ray diffraction measurements of Bragg and diffuse scattering associated with charge ordering in the inorganic compound alpha'-NaV2O5 show a continuous phase transition at a temperature of about 33.1 K. Many of this material's properties suggest a spin-Peierls transition, as established in CuGeO3 and MEM(TCNQ)(2). We compare the order parameter as well as fluctuations in the order parameter in these materials, and conclude that alpha'-NaV2O5 is dissimilar, and that the transition is two dimensional in nature, due to charge ordering associated with the fractional average valence at the vanadium site within the orthorhombic a-b plane. C1 McMaster Univ, Dept Phys & Astron, Hamilton, ON L8S 4M1, Canada. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Max Planck Inst Festkorperforsch, D-70569 Stuttgart, Germany. RP Gaulin, BD (reprint author), McMaster Univ, Dept Phys & Astron, Hamilton, ON L8S 4M1, Canada. RI Piper, Walter/B-7908-2009; Lumsden, Mark/F-5366-2012 OI Lumsden, Mark/0000-0002-5472-9660 NR 32 TC 12 Z9 12 U1 2 U2 5 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 APR 10 PY 2000 VL 84 IS 15 BP 3446 EP 3449 DI 10.1103/PhysRevLett.84.3446 PG 4 WC Physics, Multidisciplinary SC Physics GA 303DA UT WOS:000086404500058 ER PT J AU Dobrovitski, VV Katsnelson, MI Harmon, BN AF Dobrovitski, VV Katsnelson, MI Harmon, BN TI Mechanisms of decoherence in weakly anisotropic molecular magnets SO PHYSICAL REVIEW LETTERS LA English DT Article ID QUANTUM RELAXATION; MAGNETIZATION; COMPUTER AB Decoherence mechanisms in crystals of weakly anisotropic magnetic molecules, such as V-15, are studied. We show that an important decohering factor is the rapid thermal fluctuation of dipolar: interactions between magnetic molecules. A model is proposed to describe the influence of this source of decoherence. Based on the exact solution of this model, we show Char ar relatively high temperatures, about 0.5 K, the quantum coherence in a V-15 molecule is not suppressed and, in principle, can be detected experimentally Therefore, these molecules may be suitable prototype systems far study of physical processes taking place in quantum computers. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Inst Phys Met, Ekaterinburg 620219, Russia. RP Katsnelson, MI (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RI Katsnelson, Mikhail/D-4359-2012 NR 20 TC 43 Z9 43 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 10 PY 2000 VL 84 IS 15 BP 3458 EP 3461 DI 10.1103/PhysRevLett.84.3458 PG 4 WC Physics, Multidisciplinary SC Physics GA 303DA UT WOS:000086404500061 ER PT J AU Thomas, L Luning, J Scholl, A Nolting, F Anders, S Stohr, J Parkin, SSP AF Thomas, L Luning, J Scholl, A Nolting, F Anders, S Stohr, J Parkin, SSP TI Oscillatory decay of magnetization induced by domain-wall stray fields SO PHYSICAL REVIEW LETTERS LA English DT Article AB The demagnetization of a hard ferromagnetic layer via the fringing fields of domain walls created by reversing the moment of a neighboring soft ferromagnetic layer is explored experimentally An unusual oscillatory decay of the magnetic moment of the hard layer is observed using structures in which the demagnetization occurs after a few hundred cycles. This surprising observation is confirmed on a microscopic scale by detailed imaging of the magnetization of the hard layer using high resolution photoemission electron microscopy and by micromagnetic simulations. C1 IBM Corp, Almaden Res Ctr, Div Res, San Jose, CA 95120 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Thomas, L (reprint author), IBM Corp, Almaden Res Ctr, Div Res, 650 Harry Rd, San Jose, CA 95120 USA. RI Parkin, Stuart/D-2521-2012; Scholl, Andreas/K-4876-2012; Raoux, Simone/G-3920-2016 NR 18 TC 33 Z9 33 U1 1 U2 5 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 APR 10 PY 2000 VL 84 IS 15 BP 3462 EP 3465 DI 10.1103/PhysRevLett.84.3462 PG 4 WC Physics, Multidisciplinary SC Physics GA 303DA UT WOS:000086404500062 ER PT J AU Melnichenko, YB Brown, W Rangelov, S Wignall, GD Stamm, M AF Melnichenko, YB Brown, W Rangelov, S Wignall, GD Stamm, M TI Dynamic acid static correlations in solutions of polymers in liquid and supercritical solvents: dynamic light scattering and small angle neutron scattering SO PHYSICS LETTERS A LA English DT Article ID CONCENTRATION FLUCTUATIONS; VISCOELASTIC RELAXATION; CARBON-DIOXIDE; DECAY-RATE; POLYSTYRENE; SEMIDILUTE; THETA; BEHAVIOR; TEMPERATURE; CROSSOVER AB Using dynamic light scattering and small angle neutron scattering techniques we investigate: the interrelation between the dynamic and static correlation lengths in liquid and supercritical polymer solutions in the poor solvent domain Theta greater than or equal to T greater than or equal to T-c; where Theta is the theta temperature and T-c is the critical temperature of phase demixing, We observe the crossover between the hydrodynamic (T similar to Theta) and critical non-diffusive (T similar to T-c) regimes and demonstrate that the dynamic correlation length xi(d)* for polymers in liquid and supercritical polymer solvents is described by the universal function xi(d)*/xi(d)*(Theta) = F* (tau') in terms of the de Genne's scaling temperature variable tau' = (T- T-c)/(Theta - T-c). (C) 2000 Elsevier Science B.V. All tights reserved. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ Uppsala, Dept Phys Chem, S-75121 Uppsala, Sweden. Bulgarian Acad Sci, Inst Polymers, BU-1113 Sofia, Bulgaria. Inst Polymerforsch Dresden EV, D-01069 Dresden, Germany. RP Melnichenko, YB (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. RI Umlauf, Ursula/D-3356-2014 NR 46 TC 13 Z9 13 U1 0 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 APR 10 PY 2000 VL 268 IS 3 BP 186 EP 194 DI 10.1016/S0375-9601(00)00117-1 PG 9 WC Physics, Multidisciplinary SC Physics GA 305LD UT WOS:000086540800008 ER PT J AU Ling, WL Takeuchi, O Ogletree, DF Qiu, ZQ Salmeron, M AF Ling, WL Takeuchi, O Ogletree, DF Qiu, ZQ Salmeron, M TI STM studies on the growth of monolayers: Co on Cu(110) with one half monolayer of preadsorbed oxygen SO SURFACE SCIENCE LA English DT Article DE cobalt; copper; growth; magnetic interfaces; metal-metal interfaces; molecular beam epitaxy; oxygen; scanning tunneling microscopy ID GIANT MAGNETORESISTANCE; THIN-FILMS; SUPERLATTICES; CHEMISORPTION; SURFACTANT; FE AB The growth of the first cobalt monolayer (ML) on the Cu(110)-(2 x 1)O surface was studied by scanning tunneling microscopy. Extensive exchange of Cu and Co atoms takes place in the first stages of the deposition. The displaced Cu atoms form new Cu-O-Co mixed islands, with the same structure as those of the terrace surface. At similar to 0.25 ML Co, a new structure nucleates, which contains three Cu atoms, four Co atoms and two O atoms per 2 x 2 cell. The structure consists of rows in the [110] direction with an internal periodicity of two lattice units. The rows are separated from one another by two lattice units along the [001] direction, and are found both in-phase and out-of-phase relative to one another. The result is a mixed p(2 x 2) and c(2 x 4) surface. The fraction of the surface covered by the new structure increases with Co coverage, and completely covers the surface at similar to 1 ML Co. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Sci Mat, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RP Salmeron, M (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Sci Mat, Berkeley, CA 94720 USA. RI Ling, Wai Li/F-9823-2012; Ogletree, D Frank/D-9833-2016; Qiu, Zi Qiang/O-4421-2016 OI Ling, Wai Li/0000-0002-4264-5750; Ogletree, D Frank/0000-0002-8159-0182; Qiu, Zi Qiang/0000-0003-0680-0714 NR 23 TC 24 Z9 24 U1 1 U2 12 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 10 PY 2000 VL 450 IS 3 BP 227 EP 241 DI 10.1016/S0039-6028(99)01181-4 PG 15 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 301YP UT WOS:000086338400007 ER PT J AU Tzeli, D Mavridis, A Xantheas, SS AF Tzeli, D Mavridis, A Xantheas, SS TI A first principles study of the acetylene-water interaction SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID CONFIGURATION-INTERACTION CALCULATIONS; MOLECULAR WAVE-FUNCTIONS; BASIS-SET; BENCHMARK CALCULATIONS; SYSTEMATIC SEQUENCES; POTENTIAL SURFACES; DIATOMIC HYDRIDES; HYDROGEN-BOND; FORCE-FIELD; COMPLEXES AB We present an extensive study of the stationary points on the acetylene-water (AW) ground-state potential energy surface (PES) aimed in establishing accurate energetics for the two different bonding scenarios that are considered. Those include arrangements in which water acts either as a proton acceptor from one of the acetylene hydrogen atoms or a proton donor to the triple bond. We used a hierarchy of theoretical methods to account for electron correlation [MP2 (second-order Moller-Plesset), MP4 (fourth-order Moller-Plesset), and CCSD(T) (coupled-cluster single double triple)] coupled with a series of increasing size augmented correlation consistent basis sets (aug-cc-pVnZ, n=2,3,4). We furthermore examined the effect of corrections due to basis set superposition error (BSSE). We found that those have a large effect in altering the qualitative features of the PES of the complex. They are responsible for producing a structure of higher (C-2v) symmetry for the global minimum. Zero-point energy (ZPE) corrections were found to increase the stability of the C-2v arrangement. For the global (water acceptor) minimum of C-2v symmetry our best estimates are Delta E-e=-2.87 kcal/mol (Delta E-0=-2.04 kcal/mol) and a van der Waals distance of R-e=2.190 Angstrom. The water donor arrangement lies 0.3 kcal/mol (0.5 kcal/mol including ZPE corrections) above the global minimum. The barrier for its isomerization to the global minimum is E-e=0.18 kcal/mol; however, inclusion of BSSE- and ZPE-corrections destabilize the water donor arrangement suggesting that it can readily convert to the global minimum. We therefore conclude that there exists only one minimum on the PES in accordance with previous experimental observations. To this end, vibrational averaging and to a lesser extend proper description of intermolecular interactions (BSSE) were found to have a large effect in altering the qualitative features of the ground-state PES of the acetylene-water complex. (C) 2000 American Institute of Physics. [S0021-9606(00)30214-8]. C1 Natl & Kapodistrain Univ Athens, Dept Chem, Phys Chem Lab, Athens 15710, Greece. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Tzeli, D (reprint author), Natl & Kapodistrain Univ Athens, Dept Chem, Phys Chem Lab, POB 64004, Athens 15710, Greece. EM amav@arnold.chem.uoa.gr; sotiris.xantheas@pnl.gov RI Xantheas, Sotiris/L-1239-2015; OI Xantheas, Sotiris/0000-0002-6303-1037 NR 36 TC 25 Z9 25 U1 1 U2 5 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 APR 8 PY 2000 VL 112 IS 14 BP 6178 EP 6189 DI 10.1063/1.481268 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 300AX UT WOS:000086231600010 ER PT J AU Hughes, DA Lebensohn, RA Wenk, HR Kumar, A AF Hughes, DA Lebensohn, RA Wenk, HR Kumar, A TI Stacking fault energy and microstructure effects on torsion texture evolution SO PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES LA English DT Article DE texture; microstructure; twinning; dislocations; stacking fault energy; torsion ID LARGE-STRAIN SHEAR; PLASTIC-DEFORMATION; FCC POLYCRYSTALS; ZIRCONIUM ALLOYS; TAYLOR THEORY; ORIENTATION; CRYSTAL; METALS; BRASS; COMPRESSION AB A series of experiments and simulations that vary the texture and microstructure simultaneously are used to establish the role of the microstructure in texture formation in FCC metals. The stacking fault energy (SFE) of the metal, which is known to have a strong impact on texture and microstructure, is the vital parameter used to make these variations. It was determined that the wide variety of textures and microstructures observed as a function of SFE and temperature was developed by slip processes alone; twinning was not necessary, as previously thought. The different textures are caused by (i) variations in local slip patterns within a single grain, as revealed by grain subdivision into differently deforming cell blocks; and (ii) more subtly by the cell-block shape. The local selection of slip systems creating the lattice rotations within a cell block is altered by the planarity of slip. Slip planarity is controlled by the SFE and temperature. It is hypothesized that the new texture components, that are distinct from the generally accepted ideal components, are created by the different slip processes occurring as a result of low SFE and low temperature. A more subtle effect of grain subdivision is related to the cell-block shapes that develop as a function of SFE and temperature and correspond to the different textures observed. The shape of the cell block is related to the level of constraint required by the deformation. The slip pattern changes and cell-block shapes correlate with the presence or absence of certain ideal texture components whose evolution is not simulated. Materials and conditions with similar deformation microstructures developed similar textures in the experiments. C1 Sandia Natl Labs, Ctr Mat & Appl Mech, Livermore, CA 94550 USA. Univ Nacl Rosario, CONICET, Inst Fis Rosario, RA-2000 Rosario, Santa Fe, Argentina. Univ Calif Berkeley, Dept Geol, Berkeley, CA 94720 USA. Brown Univ, Div Engn, Providence, RI 02912 USA. RP Sandia Natl Labs, Ctr Mat & Appl Mech, Livermore, CA 94550 USA. RI Lebensohn, Ricardo/A-2494-2008 OI Lebensohn, Ricardo/0000-0002-3152-9105 NR 58 TC 41 Z9 41 U1 0 U2 10 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 1364-5021 EI 1471-2946 J9 P ROY SOC A-MATH PHY JI Proc. R. Soc. A-Math. Phys. Eng. Sci. PD APR 8 PY 2000 VL 456 IS 1996 BP 921 EP 953 PG 33 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 305CW UT WOS:000086522300007 ER PT J AU Stankovic, S Espenson, JH AF Stankovic, S Espenson, JH TI Oxidative cleavage of N,N-dimethylhydrazones to ketones with hydrogen peroxide, catalyzed by methyltrioxorhenium(VII) SO JOURNAL OF ORGANIC CHEMISTRY LA English DT Article ID METHYLRHENIUM TRIOXIDE; EPOXIDATION; NITRILES; PYRIDINE 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 13 TC 9 Z9 9 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0022-3263 J9 J ORG CHEM JI J. Org. Chem. PD APR 7 PY 2000 VL 65 IS 7 BP 2218 EP 2221 DI 10.1021/jo991390e PG 4 WC Chemistry, Organic SC Chemistry GA 302CV UT WOS:000086348400043 ER PT J AU Blumenfeld, R Balakrishnan, R AF Blumenfeld, R Balakrishnan, R TI Exact multi-twist solutions to the Belavin-Polyakov equation and applications to magnetic systems SO JOURNAL OF PHYSICS A-MATHEMATICAL AND GENERAL LA English DT Article ID HEISENBERG SPIN CHAIN; SOLITONS; CURVE AB The Belavin-Polyakov equation t(u) = t x t, with t(2) = 1 has been shown recently to describe the evolution of a wide class of space curves, and has several physical applications. Here, we obtain a hierarchy of exact multi-twist solutions for this nonlinear system. As on illustration, we apply our results to continuum magnetic models. When u and s denote temporal and spatial variables respectively, these twists describe very low-energy domain walls travelling along an antiferromagnetic spin chain. When they denote independent spatial variables. the solutions represent twists in the static configuration (texture) of a two-dimensional ferromagnet. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, CNLS, Los Alamos, NM 87545 USA. Inst Math Sci, Madras 600113, Tamil Nadu, India. RP Blumenfeld, R (reprint author), Univ Cambridge, Cavendish Lab, Madingley Rd, Cambridge CB3 0HE, England. NR 12 TC 3 Z9 3 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0305-4470 J9 J PHYS A-MATH GEN JI J. Phys. A-Math. Gen. PD APR 7 PY 2000 VL 33 IS 13 BP 2459 EP 2468 DI 10.1088/0305-4470/33/13/301 PG 10 WC Physics, Multidisciplinary; Physics, Mathematical SC Physics GA 304CL UT WOS:000086465100004 ER PT J AU Stafford, MA Corey, L Cao, YZ Daar, ES Ho, DD Perelson, AS AF Stafford, MA Corey, L Cao, YZ Daar, ES Ho, DD Perelson, AS TI Modeling plasma virus concentration during primary HIV infection SO JOURNAL OF THEORETICAL BIOLOGY LA English DT Article ID CYTOTOXIC T-LYMPHOCYTES; IMMUNODEFICIENCY-VIRUS; TYPE-1 INFECTION; POPULATION-DYNAMICS; IMMUNE-RESPONSES; VIRAL DYNAMICS; CELLS; VIREMIA; AIDS; REPLICATION AB During primary HIV infection the viral load in plasma increases, reaches a peak, and then declines. Phillips has suggested that the decline is due to a limitation in the number of cells susceptible to HIV infection, while other authors have suggested that the decline in viremia is due to an immune response. Here we address this issue by developing models of primary HIV-1 infection, and by comparing predictions from these models with data from ten anti-retroviral, drug-naive, infected patients. Applying nonlinear least-squares estimation, we find that relatively small variations in parameters are capable of mimicking the highly diverse patterns found in patient viral load data. This approach yields an estimate of 2.5 days for the average lifespan of productively infected cells during primary infection, a Value that is consistent with results obtained by drug perturbation experiments. We find that the data from all ten patients are consistent with a target-cell-limited model from the time of initial infection until shortly after the peak in viremia. However, the kinetics of the subsequent fall and recovery in virus concentration in some patients are not consistent with the predictions of the target-cell-limited model. We illustrate that two possible immune response mechanisms, cytotoxic T lymphocyte destruction of infected target cells and cytokine suppression of viral replication, could account for declines in viral load data not predicted by the original target-cell-limited model. We conclude that some additional process, perhaps mediated by CD8 + T cells, is important in at least some patients. (C) 2000 Academic Press. C1 Texas A&M Univ, Comp & Math Sci Dept, Corpus Christi, TX 78412 USA. Santa Fe Inst, Santa Fe, NM 87501 USA. Fred Hutchinson Canc Res Ctr, Program Infect Dis, Seattle, WA 98109 USA. Rockefeller Univ, Aaron Diamond AIDS Res Ctr, New York, NY 10016 USA. Cedars Sinai Med Ctr, Div Infect Dis, Los Angeles, CA 90048 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Stafford, MA (reprint author), Texas A&M Univ, Comp & Math Sci Dept, 6300 Ocean Dr, Corpus Christi, TX 78412 USA. FU NCRR NIH HHS [RR06555]; NIAID NIH HHS [AI40387] NR 57 TC 241 Z9 245 U1 4 U2 19 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-5193 J9 J THEOR BIOL JI J. Theor. Biol. PD APR 7 PY 2000 VL 203 IS 3 BP 285 EP 301 DI 10.1006/jtbi.2000.1076 PG 17 WC Biology; Mathematical & Computational Biology SC Life Sciences & Biomedicine - Other Topics; Mathematical & Computational Biology GA 297VY UT WOS:000086104400006 PM 10716909 ER PT J AU Gross, EA Li, GR Lin, ZY Ruuska, SE Boatright, JH Mian, IS Nickerson, JM AF Gross, EA Li, GR Lin, ZY Ruuska, SE Boatright, JH Mian, IS Nickerson, JM TI Prediction of structural and functional relationships of Repeat 1 of human interphotoreceptor retinoid-binding protein (IRBP) with other proteins SO MOLECULAR VISION LA English DT Article; Proceedings Paper CT Annual Meeting of the Association-for-Research-in-Vision-and-Ophthalmology CY MAY 09-14, 1999 CL FT LAUDERDALE, FLORIDA SP Assoc Res Vis & Ophthalmol, Natl Hlth Public Serv Award, Childern Hosp Res Fdn ID HYDROPHOBIC CLUSTER-ANALYSIS; FATTY-ACIDS; ESCHERICHIA-COLI; INFORMATION; EXPRESSION; PROTEASES; SEQUENCES; REGIONS; DOMAINS; MATRIX AB PURPOSE: We compared the structure and function of interphotoreceptor retinoid-binding protein (IRBP) related proteins and predicted domain and secondary structure within each repeat of IRBP and its relatives. We tested whether tail specific protease (Tsp), which bears sequence similarity to IRBP Domain B, binds fatty acids or retinoids, and whether IRBP possessed protease activity resembling Tsp's catalytic function. These tests helped us to learn whether the primary sequence similarities of family members extended to higher order structural and functional levels. METHODS: Predictions derived from multiple sequence alignments among IRBP and Tsp family members and secondary structure computer programs were carried out. The first repeat of human IRBP (EcR1) and Tsp were expressed, purified, and tested for binding properties. Tsp was examined for fluorescence enhancement of retinol or 16-anthroyloxy-palmitic acid (16-AP) to test for ligand binding. IRBP was tested for protease activity. RESULTS: Tsp did not exhibit fluorescence enhancement with retinol or 16-AP. IRBP did not exhibit protease activity. The positions of critical residues needed for the ligand binding properties of retinol were predicted. Primary sequence and three-dimensional similarity was found between Domain A of IRBP Repeat 3 and eglin c. CONCLUSIONS: The sequence similarity of Tsp and IRBP raised the possibility that each might share the function of the other protein: IRBP might possess protease activity or Tsp might possess retinoid or fatty acid binding activity. Our studies do not support such a shared function hypothesis, and suggest that the sequence similarity is the result of maintenance of structure. The finding of similarity to eglin c in Domain A suggests the possibility of a tight interaction between Domain A and Domain B, possibly implying the need for Domain A in retinoid-binding, and suggesting that both Domains should be present in testing mutations. The positions of predicted critical amino acids suggest models in which a large binding pocket holds the retinoid or fatty acid ligand. These predictions are tested in a companion paper. C1 Emory Univ, Emory Eye Ctr, Dept Ophthalmol, Atlanta, GA 30322 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Cell & Mol Biol, Berkeley, CA 94720 USA. RP Nickerson, JM (reprint author), Emory Univ, Emory Eye Ctr, Dept Ophthalmol, Room B5602,1365B Clifton Rd NE, Atlanta, GA 30322 USA. FU NEI NIH HHS [T32 EY 07092, P30 EY06360, R01 EY10553] NR 37 TC 9 Z9 9 U1 0 U2 0 PU MOLECULAR VISION PI ATLANTA PA C/O JEFF BOATRIGHT, LAB B, 5500 EMORY EYE CENTER, 1327 CLIFTON RD, N E, ATLANTA, GA 30322 USA SN 1090-0535 J9 MOL VIS JI Mol. Vis. PD APR 7 PY 2000 VL 6 IS 6 BP 30 EP 39 PG 10 WC Biochemistry & Molecular Biology; Ophthalmology SC Biochemistry & Molecular Biology; Ophthalmology GA 303EV UT WOS:000086409500001 PM 10756179 ER PT J AU Gross, EA Li, GR Ruuska, SE Boatright, JH Mian, IS Nickerson, JM AF Gross, EA Li, GR Ruuska, SE Boatright, JH Mian, IS Nickerson, JM TI Effects of dispersed point substitutions in Repeat 1 of human interphotoreceptor retinoid binding protein (IRBP) SO MOLECULAR VISION LA English DT Article; Proceedings Paper CT Annual Meeting of the Association-for-Research-in-Vision-and-Ophthalmology CY MAY 09-14, 1999 CL FT LAUDERDALE, FLORIDA SP Assoc Res Vis & Ophthalmol, Natl Hlth Public Serv Award, Childern Hosp Res Fdn ID ESCHERICHIA-COLI; FATTY-ACIDS; GENE; MATRIX; SLYD; SITE AB PURPOSE: The purpose of this study was to measure the effects of mutations on the retinol binding capability of human Repeat 1 of interphotoreceptor retinoid-binding protein (IRBP). First, we predicted important functional amino acids by several computer programs. We also noted the lack of shared functions between Tail-specific protease (Tsp) and IRBP, which bear sequence similarity, and this aided in predicting functional residues. We analyzed the effects of point substitutions on the retinol and fatty acid binding properties of Repeat 1 of human IRBP at 25 and 50 degrees C. METHODS: To find residues critical to retinol binding that might affect function, a series of thirteen mutations were created by site-specific mutagenesis between positions 140 and 280 in Repeat 1 of human IRBP. These mutants were expressed, purified, and tested for binding properties. The conformations of the proteins were examined by circular dichroism (CD) scans. RESULTS: Seven of the mutations exhibited reduced binding capacity, and five were not expressed at high enough levels to assess binding activity. Four of the mutants were purified, and their CD scans were very similar to those of Repeat 1. Only one of the mutations did not affect binding, folding, or expression when compare to wild type Repeat 1. CONCLUSIONS: Several IRBP mutants containing point mutations retained native structure but lost retinol binding function. The data suggest that retinol binding is affected by many different amino acid substitutions in or near a binding pocket. That even a single point substitution can profoundly affect binding without affecting overall conformation suggests that much of Domain B (from amino acid positions 80 to 300) is involved with ligand binding. This excludes three previously proposed IRBP-retinol binding mechanisms: (1) retinol binds to a small portion of the protein repeat, (2) retinol can bind to any hydrophobic patch in the protein, and (3) native conformation is not required for retinol binding to the repeat. C1 Emory Univ, Emory Eye Ctr, Dept Ophthalmol, Atlanta, GA 30322 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Cell & Mol Biol, Berkeley, CA 94720 USA. RP Nickerson, JM (reprint author), Emory Univ, Emory Eye Ctr, Dept Ophthalmol, Room B5602,1365B Clifton Rd NE, Atlanta, GA 30322 USA. FU NEI NIH HHS [R01 EY10553, P30 EY06360, T32 EY 07092] NR 25 TC 5 Z9 5 U1 0 U2 0 PU MOLECULAR VISION PI ATLANTA PA C/O JEFF BOATRIGHT, LAB B, 5500 EMORY EYE CENTER, 1327 CLIFTON RD, N E, ATLANTA, GA 30322 USA SN 1090-0535 J9 MOL VIS JI Mol. Vis. PD APR 7 PY 2000 VL 6 IS 6 BP 40 EP 50 PG 11 WC Biochemistry & Molecular Biology; Ophthalmology SC Biochemistry & Molecular Biology; Ophthalmology GA 303EV UT WOS:000086409500002 PM 10756180 ER PT J AU Robertson, DL Anderson, JP Bradac, JA Carr, JK Foley, B Funkhouser, RK Gao, F Hahn, BH Kalish, ML Kuiken, C Learn, GH Leitner, T McCutchan, F Osmanov, S Peeters, M Pieniazek, D Salminen, M Sharp, PM Wolinsky, S Korber, B AF Robertson, DL Anderson, JP Bradac, JA Carr, JK Foley, B Funkhouser, RK Gao, F Hahn, BH Kalish, ML Kuiken, C Learn, GH Leitner, T McCutchan, F Osmanov, S Peeters, M Pieniazek, D Salminen, M Sharp, PM Wolinsky, S Korber, B TI HIV-1 nomenclature proposal SO SCIENCE LA English DT Letter ID AFRICAN ORIGIN; SEQUENCE; IDENTIFICATION; THAILAND; ISOLATE C1 Univ Oxford, Oxford, England. Univ Washington, Seattle, WA 98195 USA. NIH, Bethesda, MD 20892 USA. Henry M Jackson Fdn, Rockville, MD USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. Santa Fe Inst, Santa Fe, NM 87501 USA. Univ Alabama, Birmingham, AL USA. Ctr Dis Control & Prevent, HIV AIDS & Retrovirol Branch, Atlanta, GA USA. Swedish Inst Infect Dis Control, Solna, Sweden. UNAIDS, Geneva, Switzerland. IRD, Montpellier, France. Natl Publ Hlth Inst, Helsinki, Finland. Univ Nottingham, Inst Genet, Nottingham NG7 2RD, England. Northwestern Univ, Sch Med, Chicago, IL USA. RP Robertson, DL (reprint author), Univ Oxford, Oxford, England. RI Wolinsky, Steven/B-2893-2012; Sharp, Paul/F-5783-2010; Learn, Gerald/B-6934-2011; Salminen, Mika/D-8784-2013 OI Sharp, Paul/0000-0001-9771-543X; Salminen, Mika/0000-0003-3020-0866 NR 10 TC 530 Z9 549 U1 5 U2 24 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 APR 7 PY 2000 VL 288 IS 5463 BP 55 EP 57 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 302VT UT WOS:000086387700021 PM 10766634 ER PT J AU Loots, GG Locksley, RM Blakespoor, CM Wang, ZE Miller, W Rubin, EM Frazer, KA AF Loots, GG Locksley, RM Blakespoor, CM Wang, ZE Miller, W Rubin, EM Frazer, KA TI Identification of a coordinate regulator of interleukins 4, 13, and 5 by cross-species sequence comparisons SO SCIENCE LA English DT Article ID MOUSE AB Long-range regulatory elements are difficult to discover experimentally; how-ever, they tend to be conserved among mammals, suggesting that cross-species sequence comparisons should identify them. To search for regulatory sequences, we examined about 1 megabase of orthologous human and mouse sequences for conserved noncoding elements with greater than or equal to 70% identity over at Least 100 base pairs. Ninety noncoding sequences meeting these criteria were discovered, and the analysis of 15 of these elements found that about 70% were conserved across mammals. Characterization of the Largest element in yeast artificial chromosome transgenic mice revealed it to be a coordinate regulator of three genes, interleukin-4, interleukin-13, and interleukin-5, spread over 120 kilobases. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Genome Sci Dept, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mol & Cell Biol, Berkeley, CA 94720 USA. Univ Calif San Francisco, Dept Med, San Francisco, CA 94143 USA. Univ Calif San Francisco, Dept Immunol Microbiol, San Francisco, CA 94143 USA. Univ Calif San Francisco, Howard Hughes Med Inst, San Francisco, CA 94143 USA. Penn State Univ, Dept Comp Sci & Engn, University Pk, PA 16802 USA. RP Frazer, KA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Genome Sci Dept, Berkeley, CA 94720 USA. FU NHLBI NIH HHS [HL56385]; NIAID NIH HHS [AI30663]; NIGMS NIH HHS [GM-5748202] NR 16 TC 596 Z9 615 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 APR 7 PY 2000 VL 288 IS 5463 BP 136 EP 140 DI 10.1126/science.288.5463.136 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 302VT UT WOS:000086387700051 PM 10753117 ER PT J AU Castner, EW Kennedy, D Cave, RJ AF Castner, EW Kennedy, D Cave, RJ TI Solvent as electron donor: Donor/acceptor electronic coupling is a dynamical variable SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Review ID PHOTOINDUCED ELECTRON; CHARGE-TRANSFER; SOLVATION DYNAMICS; DONATING SOLVENTS; PROTON-TRANSFER; VIBRATIONAL COHERENCE; SEMIEMPIRICAL METHODS; TRANSFER KINETICS; ACCEPTOR SYSTEMS; MATRIX-ELEMENTS AB We combine analysis of measurements by femtosecond optical spectroscopy, computer simulations, and the generalized Mulliken-Hush (GMH) theory in the study of electron-transfer reactions and electron donor-acceptor interactions. Our focus is on ultrafast photoinduced electron-transfer reactions from aromatic amine solvent donors to excited-state accepters. The experimental results from femtosecond dynamical measurements fall into three categories: six coumarin accepters reductively quenched by N,N-dimethylaniline (DMA), eight electron-donating amine solvents reductively quenching coumarin 152 (7-(dimethylamino)-4-(trifluoromethyl)coumarin), and reductive quenching dynamics of two coumarins by DMA as a function of dilution in the nonreactive solvents toluene and chlorobenzene, Applying a combination of molecular dynamics trajectories, semiempirical quantum mechanical calculations (of the relevant adiabatic electronic states), and GMH theory to the C152/DMA photoreaction, we calculate the electron donor/acceptor interaction parameter H-DA at various time frames. H-DA is strongly modulated by both inner-sphere and outer-sphere nuclear dynamics, leading us to conclude that H-DA must be considered as a dynamical variable. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Harvey Mudd Coll, Dept Chem, Claremont, CA 91711 USA. RP Castner, EW (reprint author), Rutgers State Univ, Dept Chem, 610 Taylor Rd, Piscataway, NJ 08854 USA. NR 106 TC 138 Z9 139 U1 5 U2 33 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 APR 6 PY 2000 VL 104 IS 13 BP 2869 EP 2885 DI 10.1021/jp9936852 PG 17 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 302DA UT WOS:000086349000002 ER PT J AU Feller, D Dixon, DA AF Feller, D Dixon, DA TI Predicting the heats of formation of model hydrocarbons up to benzene SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID CORRELATED MOLECULAR CALCULATIONS; GAUSSIAN-BASIS SETS; FULL CCSDT MODEL; ELECTRONIC-STRUCTURE; WAVE-FUNCTIONS; ATOMIZATION ENERGIES; TRIPLE EXCITATIONS; CHEMISTRY; METHYLENE; ATOMS AB The heats of formation of benzene and seven other small hydrocarbons (allyl, allene, cyclopropene, propene, propyne, cyclopropane. and propane) have been calculated at high levels of ab initio molecular orbital theory. Geometries and frequencies were determined, in general, with coupled cluster theory, including a perturbative treatment of the connected triple excitations and with basis sets up through augmented quadruple-zeta in quality or, in some cases, augmented quintuple-zeta. Subsequent extrapolation of the total energies to the complete I-particle basis set limit was performed, in an effort to further reduce the basis set truncation error. Additional improvements in the atomization energy were achieved by applying corrections for core/valence correlation, scalar relativistic, atomic spin-orbit, and higher-order correlation effects. Zero-point energies were based on an average of the vibrational energies obtained from the experimental Fundamentals and theoretical harmonic Frequencies. Using restricted open shell treatments for the atoms, we find the following heats of formation (kcal/mol) at 0 K: Delta H(f)(allene) = 48.1 +/- 0.5 (calcd) vs 47.4 +/- 0.3 (expt); Delta H(f)(cyclopropene) = 70.5 +/- 0.5 (calcd) vs 68.3 +/- 0.6 (expt); Delta H(f)(propyne) = 46.5 +/- 1.5 (calcd) vs 46.0 +/- 0.2 (expt); Delta H(f)(cyclopropane) = 17.4 +/- 1.5 (calcd) vs 16.8 +/- 0.1 (expt): Delta H(f)(propane) = -20.0 +/- 1.6 (calcd) vs. -19.6 +/- 0.1 (expt); Delta H(f)(propene) = 8.2 +/- 1.5 (calcd) vs 8.4 +/- 0.2 (expt): Delta H(f)(allyl) = 42.7 +/- 1.5 (calcd) vs 42.7 +/- 0.5 (expt); and Delta H(f)(benzene) = 24.7 +/- 3 (calcd) vs 24.0 +/- 0.2 (expt). C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Feller, D (reprint author), Pacific NW Lab, Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. NR 70 TC 144 Z9 144 U1 0 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD APR 6 PY 2000 VL 104 IS 13 BP 3048 EP 3056 DI 10.1021/jp994340m PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 302DA UT WOS:000086349000027 ER PT J AU Wang, LQ Liu, J Exarhos, GJ Flanigan, KY Bordia, R AF Wang, LQ Liu, J Exarhos, GJ Flanigan, KY Bordia, R TI Conformation heterogeneity and mobility of surfactant molecules in intercalated clay minerals studied by solid-state NMR SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID SELF-ASSEMBLED MONOLAYERS; LAYERED SILICATES; CHAIN DYNAMICS; C-13 NMR; SPECTROSCOPY AB The conformation heterogeneity and mobility of surfactant molecules in intercalated montmorillonite clay minerals have been investigated using variable-temperature solid-state C-13 NMR and two-dimensional proton wide-line separation (2D WISE) H-1-C-13 NMR spectroscopy. Previous FTIR studies by Vaia et al. for the first time revealed the existence of a gauche conformation of surfactant molecules in clay minerals and further illustrated the transition from an ordered conformation, to a liquid crystalline state, to completely liquidlike behavior. The NMR study reported in this paper clearly demonstrates the coexistence of order and disordered chain conformations. Two main resonance peaks are resolved and associated with the backbone alkyl chains: the resonance at 33 ppm corresponds to the ordered conformation (all-trans), and the resonance at 30 ppm corresponds to the disordered conformation (mixture of trans and gauche). The NMR technique allows detailed characterization and quantification of the conformational heterogeneity, which is difficult to determine by other techniques. Furthermore, variable-temperature NMR also directly provides quantitative information on the rigidity of the different conformations. Results from cross-polarization time constant T-CH measurements along with 2D WISE NMR suggest that molecules in the ordered all-trans conformation are as rigid as those in solid crystalline materials and that molecules in the disordered conformation are similar to those in liquid crystalline materials. Upon heating, the molecules in the disordered conformation remain more or less unchanged, while the molecules in the ordered conformation become disordered. However, the intercalated molecules in the clay minerals never attained the complete liquidlike behavior even after all the bound surfactant assumed a disordered conformation. C1 Pacific NW Lab, Richland, WA 99352 USA. Univ Washington, Seattle, WA 98125 USA. RP Wang, LQ (reprint author), Pacific NW Lab, Battelle Blvd, Richland, WA 99352 USA. NR 23 TC 133 Z9 136 U1 6 U2 14 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 APR 6 PY 2000 VL 104 IS 13 BP 2810 EP 2816 DI 10.1021/jp993058c PG 7 WC Chemistry, Physical SC Chemistry GA 302DC UT WOS:000086349300005 ER PT J AU Agarwal, R Krueger, BP Scholes, GD Yang, M Yom, J Mets, L Fleming, GR AF Agarwal, R Krueger, BP Scholes, GD Yang, M Yom, J Mets, L Fleming, GR TI Ultrafast energy transfer in LHC-II revealed by three-pulse photon echo peak shift measurements SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID LIGHT-HARVESTING-COMPLEX; A/B-PROTEIN COMPLEX; TRANSIENT ABSORPTION-SPECTROSCOPY; PHOTOSYNTHETIC ANTENNA COMPLEXES; PHOTOSYSTEM-II; EXCITATION-ENERGY; HIGHER-PLANTS; GREEN PLANTS; CHLOROPHYLL-A; ELECTRON CRYSTALLOGRAPHY AB We report the results of three-pulse photon echo peak shift (3PEPS) measurements on the light-harvesting complex II (LHC-II) of the green algae Chlamydomonas reinhardtii. Experiments were performed at two different excitation wavelengths, 670 and 650 nm. corresponding to Chi-a and Chl-b excitation, respectively, The 3PEPS data are analyzed using a new theory that incorporates the effect of energy transfer on third-order response functions. Our theoretical model separates energy transfer dynamics from the solvation dynamics arising from coupling of the electronic transitions to the protein environment. We suggest that the protein fluctuations can be described by an ultrafast solvation on a sub-100 fs time scale and a long time correlation (static disorder). Decay of the 670 nm peak shift reveals spectral equilibration time scales for Chl-rr molecules that range from 300 fs to 6 ps and agree well with other experiments. 3PEPS data at 650 nm (Chl-b excitation) reveal rapid Chl-b to Chl-b energy transfer (<1 ps), which suggests excitation hopping between a pair of Chls-b, and slow energy transfer from these Chls-b to Chls-a. Also, a 60 cm(-1) oscillatory mode is observed for Chl-b which we attribute to the first observation of coherent nuclear dynamics in LHC-II. Calculating the energy transfer dynamics based on recently proposed assignments of chromophores by solving the master equation reveals Chl-b intra- and interband energy transfer dynamics that are in qualitative agreement with the simulation model of the peak shift data. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA. Univ Chicago, Dept Mol Genet & Cell Biol, Chicago, IL 60637 USA. RP Fleming, GR (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. OI Yang, Mino/0000-0001-9504-0280 NR 66 TC 79 Z9 80 U1 3 U2 17 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 APR 6 PY 2000 VL 104 IS 13 BP 2908 EP 2918 DI 10.1021/jp9915578 PG 11 WC Chemistry, Physical SC Chemistry GA 302DC UT WOS:000086349300018 ER PT J AU Bistrovic, B Klabucar, D AF Bistrovic, B Klabucar, D TI Anomalous gamma -> 3 pi amplitude in a bound-state approach SO PHYSICS LETTERS B LA English DT Article DE chiral symmetry breaking; constituent quarks; nonperturbative QCD and hadron phenomenology; axial anomaly; Schwinger-Dyson equations ID BETHE-SALPETER APPROACH; PSEUDOSCALAR MESONS; VECTOR-MESONS; FORM-FACTOR; DYSON; PION AB The form factor for the anomalous process gamma pi(+) --> pi(+)pi(0), which is presently being measured at CEBAF, is calculated in the Schwinger-Dyson approach in conjunction with an impulse approximation. The form factors obtained by us are compared with the ones predicted by the simple constituent quark loop model, vector meson dominance and chiral perturbation theory, as well as the scarce already available data. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Old Dominion Univ, Dept Phys, Norfolk, VA 23529 USA. Jefferson Lab, Newport News, VA 23606 USA. Univ Zagreb, Fac Sci, Dept Phys, Zagreb 10000, Croatia. RP Bistrovic, B (reprint author), Old Dominion Univ, Dept Phys, 4600 Elkhorn Ave, Norfolk, VA 23529 USA. NR 24 TC 17 Z9 17 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 APR 6 PY 2000 VL 478 IS 1-3 BP 127 EP 136 DI 10.1016/S0370-2693(00)00241-0 PG 10 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 305LB UT WOS:000086540600015 ER PT J AU Balazs, C Yuan, CP AF Balazs, C Yuan, CP TI Higgs boson production at the LHC with soft gluon effects SO PHYSICS LETTERS B LA English DT Article ID TRANSVERSE-MOMENTUM DISTRIBUTION; TO-BACK JETS; HADRONIC COLLISIONS; W-BOSON; COLLIDERS; QCD; ANNIHILATION; RESUMMATION; PAIR AB We present results of QCD corrections to Higgs boson production at the CERN Large Hadron Collider. Potentially large logarithmic contributions from multiple soft-gluon emission are summed up to all order in the strong coupling. Various kinematical distributions, including the Higgs transverse momentum, are predicted with @(alpha(s)(3)) precision. Comparison is made to outputs of the popular Monte Carlo event generator PYTHIA. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Hawaii, Dept Phys & Astron, Honolulu, HI 96822 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Natl Tsing Hua Univ, Natl Ctr Theoret Sci, Hsinchu, Taiwan. Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. RP Balazs, C (reprint author), Univ Hawaii, Dept Phys & Astron, Honolulu, HI 96822 USA. NR 44 TC 67 Z9 67 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 APR 6 PY 2000 VL 478 IS 1-3 BP 192 EP 198 DI 10.1016/S0370-2693(00)00270-7 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 305LB UT WOS:000086540600022 ER PT J AU Eboli, OJP Gonzalez-Garcia, MC Lietti, SM Novaes, SF AF Eboli, OJP Gonzalez-Garcia, MC Lietti, SM Novaes, SF TI Probing intermediate mass Higgs interactions at the CERN large hadron collider SO PHYSICS LETTERS B LA English DT Article ID TEVATRON COLLIDER; BOSON PRODUCTION; COUPLINGS; CONSTRAINTS; PHYSICS; SEARCH; SECTOR; DECAY; LHC AB We analyze the potentiality of the CERN Large Hadron Collider to probe the Higgs boson couplings to the electroweak gauge bosons. We parametrize the possible deviations of these couplings due to new physics in a model independent way, using the most general dimension-six effective lagrangian where the SU(2)(L) x U(1)(Y) is realized linearly. For intermediate Higgs masses, the decay channel into two photons is the most important one for Higgs searches at the LHC, We study the effects of these new interactions on the Higgs production mechanism and its subsequent decay into two photons. We show that the LHC will be sensitive to new physics scales beyond the present limits extracted from the LEP and Tevatron physics. (C) 2000 Elsevier Science B,V, All rights reserved. C1 Univ Estadual Paulista, Inst Fis Teor, BR-01405900 Sao Paulo, Brazil. Univ Valencia, CSIC, Inst Fis Corpuscular IFIC, Edificio Inst Paterna, Valencia 46071, Spain. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Univ Estadual Paulista, Inst Fis Teor, Rua Pamplona 145, BR-01405900 Sao Paulo, Brazil. RI Eboli, Oscar/D-4544-2012; Novaes, Sergio/D-3532-2012; Panella, Orlando/L-5359-2014 OI Eboli, Oscar/0000-0003-4107-6012; Novaes, Sergio/0000-0003-0471-8549; Panella, Orlando/0000-0003-4262-894X NR 25 TC 16 Z9 17 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 EI 1873-2445 J9 PHYS LETT B JI Phys. Lett. B PD APR 6 PY 2000 VL 478 IS 1-3 BP 199 EP 207 DI 10.1016/S0370-2693(00)00240-9 PG 9 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 305LB UT WOS:000086540600023 ER PT J AU Darwin, C We-Fu, C Keung, WY AF Darwin, C We-Fu, C Keung, WY TI Additional two-loop contributions to electric dipole moments in supersymmetric theories SO PHYSICS LETTERS B LA English DT Article AB We calculate the two-loop contributions to the electric dipole moments of the electron and the neutron mediated by charged Higgs in a generic supersymmetric theories. The new contributions are originated from the potential CP violation in the trilinear couplings of the charged Higgs bosons to the scaler-top or the scaler-bottom quarks. These couplings did not receive stringent constraints directly. We find observable effects for a sizable portion of the parameter space related to the third generation scalar-quarks in the minimal supersymmetric standard model. (C) 2000 Elsevier Science B.V. All rights reserved. C1 NCTS, Hsinchu 30043, Taiwan. Natl Tsing Hua Univ, Dept Phys, Hsinchu 30043, Taiwan. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Illinois, Dept Phys, Chicago, IL 60607 USA. RP Darwin, C (reprint author), NCTS, Hsinchu 30043, Taiwan. RI Abreu, Pedro/L-2220-2014; Barao, Fernando/O-2357-2016; OI Andringa, Sofia/0000-0002-6397-9207; Abreu, Pedro/0000-0002-9973-7314; Barao, Fernando/0000-0002-8346-9941; Keung, Wai-Yee/0000-0001-6761-9594 NR 12 TC 65 Z9 65 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 APR 6 PY 2000 VL 478 IS 1-3 BP 239 EP 246 DI 10.1016/S0370-2693(00)00268-9 PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 305LB UT WOS:000086540600028 ER PT J AU Lins, RD Straatsma, TP Briggs, JM AF Lins, RD Straatsma, TP Briggs, JM TI Similarities in the HIV-1 and ASV integrase active sites upon metal cofactor binding SO BIOPOLYMERS LA English DT Article DE HIV-1 integrase; molecular dynamics; AIDS; active site conformational change ID HUMAN-IMMUNODEFICIENCY-VIRUS; DNA-BINDING; TYPE-1 INTEGRASE; CATALYTIC DOMAIN; RETROVIRAL INTEGRASE; ESSENTIAL DYNAMICS; DIVALENT-CATIONS; PROTEIN; RESIDUES; IDENTIFICATION AB The HIV-1 integrase, which is essential for viral replication, catalyzes the insertion of viral DNA into the host chromosome thereby recruiting host cell machinery into making viral proteins. It represents the third main HN enzyme target for inhibitor design, the first two being the reverse transcriptase and the protease. We report here a fully hydrated 2 ns molecular dynamics simulation performed using parallel NWChem3.2.1 with the AMBER95 force field. The HIV-1 integrase catalytic domain previously determined by crystallography (IB9D) and modeling including two Mg2+ ions placed into the active site based on an alignment against an ASV integrase structure containing two divalent metals (1VSH), was used as the starting structure. The simulation reveals a high degree of flexibility in the region of residues 140-149 even in the presence of a second divalent metal ion and a dramatic conformational change of the side chain of E152 when the second metal ion is present. This study shows similarities in the behavior of the catalytic residues in the HIV-1 and ASV integrases upon metal binding. The present simulation also provides support to the hypothesis that the second metal ion is likely to be carried into the HIV-1 integrase active site by the substrate, a strand of DNA. (C) 2000 John Wiley & Sons, Inc. Biopoly 53: 308-315, 2000. C1 Univ Houston, Dept Biol & Biochem, Houston, TX 77204 USA. Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Briggs, JM (reprint author), Univ Houston, Dept Biol & Biochem, Houston, TX 77204 USA. RI Lins, Roberto/J-7511-2012 OI Lins, Roberto/0000-0002-3983-8025 FU NIGMS NIH HHS [GM56553] NR 44 TC 25 Z9 25 U1 0 U2 0 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0006-3525 J9 BIOPOLYMERS JI Biopolymers PD APR 5 PY 2000 VL 53 IS 4 BP 308 EP 315 DI 10.1002/(SICI)1097-0282(20000405)53:4<308::AID-BIP3>3.0.CO;2-H PG 8 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 304DK UT WOS:000086467400003 PM 10685051 ER PT J AU Stewart, FF Singler, RE Harrup, MK Peterson, ES Lash, RP AF Stewart, FF Singler, RE Harrup, MK Peterson, ES Lash, RP TI Electron beam crosslinking of fluoroalkoxy, methoxyethoxyethoxy, and substituted phenoxy polyphosphazenes: Physical and chemical characterization and comparison to a thermally induced free radical process and ionic complexation SO JOURNAL OF APPLIED POLYMER SCIENCE LA English DT Article DE polyphosphazenes; crosslinking; electron beam processing; lithium complexation; polymer swelling; free radical crosslinking ID CROSS-LINKING; SIDE GROUPS; RADIATION AB Electron beam, thermal free radical, and cationic complexation mechanisms have been employed to investigate crosslinking in selected polyphosphazenes. In polyphosphazenes functionalized with o-allylphenol to facilitate free radical crosslinking, maximum crosslink density was achieved after 10 min at 130 degrees C utilizing benzoyl peroxide as an initiator. Electron beam radiation was found to give an increased crosslink density with increased dose. The dose-crosslink density relationship observed for a aryloxyphosphazene terpolymer PPXP also was seen in poly[bis(2,2'-(methoxyethoxy)ethoxy)phosphazene] (MEEP). However, with two lots of a fluoroalkoxyphosphazene an initial crosslink density was achieved at a lower electron beam exposure with no additional crosslink density observed with increasing dose. These measurements are observations of net crosslinking, which is the result of crosslinking processes balanced by chain scission processes. DSC revealed that neither thermal- nor electron beam-initiated crosslinking cause any significant change in the T-g, of the polymer. Metal ion complexation with MEEP consistently gave T-g values that were higher than MEEP. The T-g values measured for both MEEP and the lithium-complexed MEEP were unaffected by electron beam irradiation. These data suggest the location of lithium complexation may be at the nitrogen lone electron pair on the backbone, representing a new mechanism of lithium complexation in phosphazenes. (C) 2000 John Wiley & Sons, Inc. C1 Lockheed Martin Idaho Technol Co, Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Singler, RE (reprint author), Lockheed Martin Idaho Technol Co, Idaho Natl Engn & Environm Lab, POB 1625, Idaho Falls, ID 83415 USA. NR 31 TC 15 Z9 16 U1 0 U2 1 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 APR 4 PY 2000 VL 76 IS 1 BP 55 EP 66 DI 10.1002/(SICI)1097-4628(20000404)76:1<55::AID-APP8>3.0.CO;2-F PG 12 WC Polymer Science SC Polymer Science GA 278UZ UT WOS:000085008500008 ER PT J AU Ponomarev, AL Sewell, TD Durning, CJ AF Ponomarev, AL Sewell, TD Durning, CJ TI Adsorption of isolated, flexible polymers onto a strongly attracting surface SO MACROMOLECULES LA English DT Article ID MONTE-CARLO; DYNAMICS; INTERFACES; SIMULATION; MOLECULES; CHAINS; MODEL AB We investigate by lattice Monte Carlo simulation the kinetics of adsorption of isolated linear homopolymers onto a flat surface with a strong, short-ranged attraction for the segments. We focus on limiting cases corresponding to strong physisorption and chemisorption. initially, the polymer has a conformation representative of the bulk (dilute) solution, but with a few peripheral segments in contact with the surface. Subsequent adsorption is tracked by monitoring a number of mechanical variables. By averaging over initial configurations, and over appropriately selected time windows along individual trajectories, we determine the adsorption kinetics and find the effects of chain length and segment/surface interactions on the characteristic time for adsorption, tau(ads). For all situations investigated, tau(ads) increases algebraically with the number of segments N; i.e., tau(ads) similar to N-alpha, with alpha being considerably smaller than that for scaling of the bulk relaxation time of the chain, tau(R). We find that alpha depends on the details of the short-ranged surface/segment interaction potential. The results are rationalized with scaling-level analysis. C1 Columbia Univ, Dept Chem Engn & Appl Chem, New York, NY 10027 USA. Columbia Univ, Dept Appl Phys & Appl Math, New York, NY 10027 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Durning, CJ (reprint author), Columbia Univ, Dept Chem Engn & Appl Chem, New York, NY 10027 USA. NR 26 TC 22 Z9 22 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 APR 4 PY 2000 VL 33 IS 7 BP 2662 EP 2669 DI 10.1021/ma9808732 PG 8 WC Polymer Science SC Polymer Science GA 302AV UT WOS:000086343500052 ER PT J AU Matkin, LS Gleeson, HF Mach, P Huang, CC Pindak, R Srajer, G Pollmann, J Goodby, JW Hird, M Seed, A AF Matkin, LS Gleeson, HF Mach, P Huang, CC Pindak, R Srajer, G Pollmann, J Goodby, JW Hird, M Seed, A TI Resonant x-ray scattering at the Se edge in liquid crystal free-standing films and devices SO APPLIED PHYSICS LETTERS LA English DT Article ID PHASES AB Resonant x-ray diffraction was carried out at the Se K edge in thick free-standing films of a selenophene liquid crystalline material, revealing detail of the structure of the ferro-, ferri-, and antiferroelectric phases. The ferrielectric phase was shown to have a three-layer superlattice. Moreover, the structure of a lower temperature hexatic phase was established. For the antiferroelectric phase, investigations were also carried out in a planar device configuration. The device allowed resonant scattering experiments to be carried out with and without the application of an electric field and resonant data are compared with electro-optic measurements carried out on the same device. (C) 2000 American Institute of Physics. [S0003-6951(00)01513-8]. C1 Univ Manchester, Dept Phys & Astron, Manchester M13 9PL, Lancs, England. Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. Univ Hull, Dept Chem, Hull HU6 7RJ, N Humberside, England. RP Gleeson, HF (reprint author), Univ Manchester, Dept Phys & Astron, Manchester M13 9PL, Lancs, England. RI Hirst, Linda/A-4862-2008 OI Hirst, Linda/0000-0002-8306-9366 NR 17 TC 31 Z9 31 U1 1 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 3 PY 2000 VL 76 IS 14 BP 1863 EP 1865 DI 10.1063/1.126193 PG 3 WC Physics, Applied SC Physics GA 298JC UT WOS:000086134700024 ER PT J AU Carlin, JA Ringel, SA Fitzgerald, EA Bulsara, M Keyes, BM AF Carlin, JA Ringel, SA Fitzgerald, EA Bulsara, M Keyes, BM TI Impact of GaAs buffer thickness on electronic quality of GaAs grown on graded Ge/GeSi/Si substrates SO APPLIED PHYSICS LETTERS LA English DT Article ID MOLECULAR-BEAM EPITAXY; SOLAR-CELLS; SI; GE; LAYERS AB Minority carrier lifetimes and interface recombination velocities for GaAs grown on a Si wafer using compositionally graded GeSi buffers have been investigated as a function of GaAs buffer thickness using monolayer-scale control of the GaAs/Ge interface nucleation during molecular beam epitaxy. The GaAs layers are free of antiphase domain disorder, with threading dislocation densities measured by etch pit density of 5 x 10(5)-2 x 10(6) cm(-2). Analysis indicates no degradation in either minority carrier lifetime or interface recombination velocity down to a GaAs buffer thickness of 0.1 mu m. In fact, record high minority carrier lifetimes exceeding 10 ns have been obtained for GaAs on Si with a 0.1 mu m GaAs buffer. Secondary ion mass spectroscopy reveals that cross diffusion of Ga, As, and Ge at the GaAs/Ge interface formed on the graded GeSi buffers are below detection limits in the interface region, indicating that polarity control of the GaAs/Ge interface formed on GeSi/Si substrates can be achieved. (C) 2000 American Institute of Physics. [S0003-6951(00)03214-9]. C1 Ohio State Univ, Dept Elect Engn, Columbus, OH 43210 USA. MIT, Cambridge, MA 02139 USA. Amberwave Syst Corp, Woburn, MA 01801 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Carlin, JA (reprint author), Ohio State Univ, Dept Elect Engn, Columbus, OH 43210 USA. NR 19 TC 76 Z9 77 U1 2 U2 24 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 3 PY 2000 VL 76 IS 14 BP 1884 EP 1886 DI 10.1063/1.126200 PG 3 WC Physics, Applied SC Physics GA 298JC UT WOS:000086134700031 ER PT J AU Saks, NS Agarwal, AK Mani, SS Hegde, VS AF Saks, NS Agarwal, AK Mani, SS Hegde, VS TI Low-dose nitrogen implants in 6H-silicon carbide SO APPLIED PHYSICS LETTERS LA English DT Article AB Low-dose n-type nitrogen implants in 6H-SiC have been studied using the Hall effect. Previous studies of doping by implantation in SiC have concentrated on heavily doped layers such as required for transistor sources and drains. Here, we focus on more lightly doped layers, e.g., such as required for the active regions of high-voltage power devices. The low-dose N implants are found to activate more readily than high doses. Almost ideal N-implanted layers with a donor density of similar to 1 x 10(17)/cm(3) and a low residual acceptor density from implant damage of only similar to 1.5 x 10(15)/cm(3) have been obtained after a 1400 degrees C anneal. (C) 2000 American Institute of Physics. [S0003-6951(00)03714-1]. C1 USN, Res Lab, Washington, DC 20375 USA. CREE Res Inc, Durham, NC 27703 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Northrop Grumman Corp, Pittsburgh, PA 15235 USA. RP Saks, NS (reprint author), USN, Res Lab, Code 6813, Washington, DC 20375 USA. NR 13 TC 9 Z9 9 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 3 PY 2000 VL 76 IS 14 BP 1896 EP 1898 DI 10.1063/1.126204 PG 3 WC Physics, Applied SC Physics GA 298JC UT WOS:000086134700035 ER PT J AU Solovyov, VF Wiesmann, HJ Wu, LJ Zhu, YM Suenaga, M AF Solovyov, VF Wiesmann, HJ Wu, LJ Zhu, YM Suenaga, M TI Kinetics of YBa2Cu3O7 film growth by postdeposition processing SO APPLIED PHYSICS LETTERS LA English DT Article ID BA2YCU3O7-X THIN-FILMS AB The ex situ growth of thick textured YBa2Cu3O7 films on SrTiO3 substrates was investigated in order to find the factors, which influence growth kinetics. It was found that the growth rate of YBa2Cu3O7 films remains constant during heat treatment and is proportional to the square root of the H2O partial pressure in the processing atmosphere. Using transmission electron microscopy, we observed that the growth of the YBa2Cu3O7 films proceeds from a thin, similar to 7-nm-thick, layer of liquid located at the growth front. Chemical analysis of this layer and the adjacent material suggests that decomposition of an oxifluoride compound in the precursor film occurs at the liquid layer-precursor film interface. The rate of this decomposition reaction defines the growth rate of YBa2Cu3O7. Using a simple model we show that rate of this reaction is limited by the out-diffusion of the decomposition product HF. (C) 2000 American Institute of Physics. [S0003-6951(00)03014-X]. C1 Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. RP Solovyov, VF (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. RI Solovyov, Vyacheslav/A-7724-2009; OI Solovyov, Vyacheslav/0000-0003-1879-9802 NR 10 TC 56 Z9 60 U1 1 U2 7 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 3 PY 2000 VL 76 IS 14 BP 1911 EP 1913 DI 10.1063/1.126209 PG 3 WC Physics, Applied SC Physics GA 298JC UT WOS:000086134700040 ER PT J AU Carlson, CM Rivkin, TV Parilla, PA Perkins, JD Ginley, DS Kozyrev, AB Oshadchy, VN Pavlov, AS AF Carlson, CM Rivkin, TV Parilla, PA Perkins, JD Ginley, DS Kozyrev, AB Oshadchy, VN Pavlov, AS TI Large dielectric constant (epsilon/epsilon(0)> 6000) Ba0.4Sr0.6TiO3 thin films for high-performance microwave phase shifters SO APPLIED PHYSICS LETTERS LA English DT Article ID CAPACITORS; VARACTORS AB We deposited epitaxial Ba0.4Sr0.6TiO3 (BST) films via laser ablation on MgO and LaAlO3 (LAO) substrates for tunable microwave devices. Postdeposition anneals (similar to 1100 degrees C in O-2) improved the morphology and overall dielectric properties of films on both substrates, but shifted the temperature of maximum dielectric constant (T-max) up for BST/LAO and down for BST/MgO. These substrate-dependent T-max shifts had opposite effects on the room-temperature dielectric properties. Overall, BST films on MgO had the larger maximum dielectric constant (epsilon/epsilon(0)greater than or equal to 6000) and tunability (Delta epsilon/epsilon greater than or equal to 65%), but these maxima occurred at 227 K. 30 GHz phase shifters made from similar films had figures of merit (ratio of maximum phase shift to insertion loss) of similar to 45 degrees/dB and phase shifts of similar to 400 degrees under 500 V (similar to 13 V/mu m) bias, illustrating their utility for many frequency-agile microwave devices. (C) 2000 American Institute of Physics. [S0003-6951(00)02814-X]. C1 Univ Colorado, Dept Phys, Boulder, CO 80309 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. Electrotech Univ St Petersburg, St Petersburg 197376, Russia. RP Carlson, CM (reprint author), Univ Colorado, Dept Phys, Boulder, CO 80309 USA. NR 13 TC 194 Z9 210 U1 2 U2 28 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 3 PY 2000 VL 76 IS 14 BP 1920 EP 1922 DI 10.1063/1.126212 PG 3 WC Physics, Applied SC Physics GA 298JC UT WOS:000086134700043 ER PT J AU Eshel, M Bino, A Felner, I Johnston, DC Luban, M Miller, LL AF Eshel, M Bino, A Felner, I Johnston, DC Luban, M Miller, LL TI Polynuclear chromium(III) carboxylates. 1. Synthesis, structure, and magnetic properties of an octanuclear complex with a ring structure SO INORGANIC CHEMISTRY LA English DT Article ID MOLECULAR-STRUCTURE; CRYSTAL-STRUCTURE; SOLID-STATE; ASSEMBLIES; CLUSTER; CAVITY; CORE; ACID AB A novel cyclic octanuclear chromium(III) complex with hydroxo and acetato bridging ligands was isolated and its structure determined by X-ray crystallography. The complex [Cr-8(ON)(12)(OAc)(12)] (1) (OAc- = CH3CO2-), as found in crystals of 1.34H2(O), is obtained by refluxing an aqueous solution of the trinuclear "basic" chromium acetate. 1.34H(2)O crystallizes in the tetragonal space group I (4) over bar 2d with the following unit cell dimensions: a 16.592(2) Angstrom, c = 31.557(4) Angstrom, V = 8687(1) Angstrom(3), and Z = 2. A total of 2000 unique data with I > 3 sigma(I) were used to solve and refine the structure to R(F-0) = 0.066 and R-w(F-0) = 0.085. The structure consists of eight Cr(III) ions that form a ring structure and are bridged by hydroxo and acetato ligands. Each of the two neighboring metal atoms in 1 is bridged either by two OH- ligands and one OAc- ligand, with a Cr ... Cr distance of 2.949(2) Angstrom, or by two OAc- ligands and one OH- ligand, with a Cr ... Cr distance of 3.383(2) Angstrom in an alternating fashion. The complex resides on a crystallographic 4 center, and the overall symmetry of 1 is S-4. The magnetic susceptibility of 1.34H(2)O was measured in the temperature range of 5-240 K. Our theoretical modeling of the susceptibility data indicates alternating antiferromagnetic exchange interactions between adjacent spin 3/2 Cr3+ ions around the ring, of magnitude J/k(B) = 13.7 and 8.9 K, respectively. C1 Hebrew Univ Jerusalem, Dept Inorgan & Analyt Chem, IL-91904 Jerusalem, Israel. Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Bino, A (reprint author), Hebrew Univ Jerusalem, Dept Inorgan & Analyt Chem, IL-91904 Jerusalem, Israel. NR 39 TC 73 Z9 73 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 APR 3 PY 2000 VL 39 IS 7 BP 1376 EP 1380 DI 10.1021/ic9907009 PG 5 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 302QF UT WOS:000086376100009 PM 12526439 ER PT J AU Graudejus, O Wilkinson, AP Bartlett, N AF Graudejus, O Wilkinson, AP Bartlett, N TI Structural features of Ag[AuF4] and Ag[AuF6] and the stuctural relationship of Ag[AgF4](2) and Au[AuF4](2) to Ag[AuF4](2) SO INORGANIC CHEMISTRY LA English DT Article ID ANHYDROUS HYDROGEN-FLUORIDE; MAGNETIC-PROPERTIES; CRYSTAL-STRUCTURE; ROOM-TEMPERATURE; SILVER; GOLD; COMPLEXES; OXIDATION; PALLADIUM; PLATINUM AB Synchrotron radiation X-ray powder diffraction data (SPDD) have been obtained for Ag[AgF4](2), Au[AuF4](2), Ag[AuF4], and Ag[AuF4](2). Ag[AgF4](2) and Au[AuF4](2) are isostructural with Ag[AuF4](2), space group (SG) P2(l)/n, Z = 2, with the following: for Ag[AgF4](2) a = 5.04664(8), b = 11.0542(2), c = 5.44914(9) Angstrom, beta 97.170(2)degrees; for Au[AuF4](2) a = 5.203(2), b = 11.186(3), c = 5.531(2) Angstrom, beta 90.55(2)degrees. The structure of Ag[AgF4](2) was refined successfully (SPDD) applying the Rietveld method, yielding the following interatomic distances (Angstrom): Ag-II-F = 2.056(12), 2.200(13), 2.558(13); Ag-III-F = two at 1.846(12), others = 1.887(12), 1.909(13), 2.786(12), 2.796(12), 2.855(12). AgAuF4, like other AA'F-4 salts (A = Na-Rb; A' = Ag, Au), crystallizes in the KBrF4 structure type, SG I4/mcnn (140), Z = 4 with a = 5.79109(6), c 10.81676(7) Angstrom. SPDD gave (in Angstrom) four Au-III-F = 1.89(1) and eight Ag-I-F = 2.577(7). SPDD for AgAuF6 confirmed that it has the LiSbF6 structure, 15.0451(6) Angstrom. SG R (3) over bar, Z = 3, with a = 5.2840(2), c = 15.0451(6) Angstrom. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Georgia Inst Technol, Sch Chem & Biochem, Atlanta, GA 30332 USA. RP Bartlett, N (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Chem Sci, Berkeley, CA 94720 USA. RI Wilkinson, Angus/C-3408-2008 OI Wilkinson, Angus/0000-0003-2904-400X NR 25 TC 13 Z9 13 U1 1 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD APR 3 PY 2000 VL 39 IS 7 BP 1545 EP 1548 DI 10.1021/ic991178t PG 4 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 302QF UT WOS:000086376100032 PM 12526462 ER PT J AU Jiao, XD Espenson, JH AF Jiao, XD Espenson, JH TI Kinetics of manganese(III) acetate in acetic acid: Generation of Mn(III) with Co(III), Ce(IV), and dibromide radicals; Reactions of Mn(III) with Mn(II), Co(II), hydrogen bromide, and alkali bromides SO INORGANIC CHEMISTRY LA English DT Article ID COBALT(III) ACETATE; CATALYZED AUTOXIDATION; CRYSTAL-STRUCTURE; OXIDATION; HYDROCARBONS; CHEMISTRY AB The reaction of cobalt(III) acetate with excess manganese(II) acetate in acetic acid occurs in two stages, since the two forms Co(IIIc) and Co(IIIs) are not rapidly equilibrated and thus react independently. The rate constants at 24.5 degrees C are k(c)= 37.1 +/- 0.6 L mol(-1) s(-1) and k(s)= 6.8 +/- 0.2 L mol(-1) s(-1) at 24.5 degrees C in glacial acetic acid. The Mn(LII) produced forms a dinuclear complex. with the excess of Mn(LT). This was studied independently and is characterized by the rate constant (3.43 +/- 0.01) x 10(-1) L mol(-1) s(-1) at 24.5 degrees C. A similar interaction between Mn(III) and Co(II) is substantially slower, with k = (3.73 +/- 0.05) x 10(-1) L mol(-1) s(-1) at 24.5 degrees C. Mn(II) is also oxidized by Ce(TV), according to the rate law -d[Ce(IV)]/dt = k[Mn(II)](2)[Ce(IV)], where k = (6.0 +/- 0.2) x 10(4) L-2 mol(-2) s(-1). The reaction between Mn(II) and HBr2., believed to be involved in the mechanism by which Mn(III) oxidizes HBr, was studied by laser photolysis; the rate constant is (1.48 +/- 0.04) x 10(8) L mol(-1) s(-1) at similar to 23 degrees C in HOAc. Oxidation of Co(II) by HBr2. has the rate constant (3.0 +/- 0.1) x 10(7) L mol(-1) s(-1). The oxidation of HBr by Mn(III) is second order with respect to [HBr]; k = (4.10 +/- 0.08) x 10(5) L-2 mol(-2) s(-1) at 4.5 degrees C in 10% aqueous HOAc. Similar reactions with alkali metal bromides were studied; their rate constants are 17-23 times smaller. This noncomplementary reaction is believed to follow that rate law so that HBr2. and not Br-. (higher in Gibbs energy by 0.3 V) can serve as the intermediate. The analysis of the reaction steps then requires that the oxidation of HBr2. to Br-2 by Mn(III) be diffusion controlled, which is consistent with the driving force and seemingly minor reorganization. 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 37 TC 17 Z9 17 U1 1 U2 12 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 APR 3 PY 2000 VL 39 IS 7 BP 1549 EP 1554 DI 10.1021/ic991213w PG 6 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 302QF UT WOS:000086376100033 PM 12526463 ER PT J AU Bryan, JC Kavallieratos, K Sachleben, RA AF Bryan, JC Kavallieratos, K Sachleben, RA TI Unusual ligand coordination for cesium SO INORGANIC CHEMISTRY LA English DT Article ID ALKALINE-EARTH CATIONS; X-RAY; CRYSTAL-STRUCTURE; PI INTERACTIONS; COMPLEXES; POLYETHERS; CHEMISTRY; SYSTEMS; DESIGN; ANIONS AB When complexed by tetrabenzo-24-crown-8, the cesium ion can accommodate unprecedented ligation, The structures of the following complexes are presented. [Cs(tetrabenzo-24-crown-8)(eta(1)-NCMe)(2)(eta(2)-NCME)][NO3] (1): triclinic P (1) over bar, a = 12.0119(14) Angstrom, b = 13.3680(15) Angstrom, c = 13.7859(12) Angstrom, alpha = 89.124(8)degrees, beta = 66.928(9)degrees, gamma = 71.536(10)degrees V= 1916.7(4) Angstrom(3), Z = 2: [CS(tetrabenzo-24-crown-8)(eta(1)-NCMe)(2)(eta(2)-CH2Cl2)[NO3] (2): triclinic, P (1) over bar, a = 12.295(3) Angstrom, b = 13.295(3) Angstrom, c = 13.782(3) Angstrom, alpha = 89.105(17)degrees, beta = 66.096(18)degrees, gamma = 71.980(19)degrees, V = 1929.5(8) Angstrom(3), Z = 2, These structures are the first reported examples of linear eta(2)-acetonitrile coordination to any metal ion and the first structures illustrating eta(2)-acetonitrile and dichloromethane ligation to an alkali metal ion. possible steric and electronic origins of these unusual metal-ligand interactions are discussed. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Bryan, JC (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. NR 66 TC 20 Z9 20 U1 0 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD APR 3 PY 2000 VL 39 IS 7 BP 1568 EP 1572 DI 10.1021/ic991203v PG 5 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 302QF UT WOS:000086376100036 PM 12526466 ER PT J AU Colella, TA Bullock, TNJ Russell, LB Mullins, DW Overwijk, WW Luckey, CJ Pierce, RA Restifo, NP Engelhard, VH AF Colella, TA Bullock, TNJ Russell, LB Mullins, DW Overwijk, WW Luckey, CJ Pierce, RA Restifo, NP Engelhard, VH TI Self-tolerance to the murine homologue of a tyrosinase-derived melanoma antigen: Implications for tumor immunotherapy SO JOURNAL OF EXPERIMENTAL MEDICINE LA English DT Article DE tyrosinase; self-tolerance; MHC class I; cytotoxic T lymphocytes; immunotherapy ID CYTOLYTIC T-LYMPHOCYTES; ALTERED PEPTIDE LIGAND; CLASS-I MOLECULES; INFILTRATING LYMPHOCYTES; REJECTION ANTIGEN; HLA-A2 MELANOMAS; TISSUE ANTIGENS; HIGH-AFFINITY; CELL-LINES; IDENTIFICATION AB Thr human tyrosinase-derived peptide YMDGTMSQV is presented on the surface of human histocompatibility leukocyte antigen (HLA)-A*0201(+) melanomas and has been suggested to be a tumor antigen despite the Get that tyrosinase is also expressed in melanocytes. To gain information about immunoreactivity and self-tolerance to this antigen, we established a model using the murine tyrosinase-derived homologue of this peptide FMDGTMSQV, together with transgenic mice expressing the HLA-A*0201 recombinant molecule AAD. The murine peptide was processed and presented by AAD similarly to its human counterpart. After immunization with recombinant vaccinia virus encoding murine tyrosinase, we detected a robust AAD-restricted cytotoxic T lymphocyte (CTL) response to FMDGTMSQV in AAD transgenic mice in which the entire tyrosinase gene had been deleted by a radiation-induced mutation. A residual response was observed in the AAD(+)tyrosinase(+) mice after activation under certain conditions. At least some of these residual CTLs in AAD(+)tyrosinase(+) mice were of high avidity and induced vitiligo upon adoptive transfer into AAD(+)tyrosinase(+) hosts. Collectively, these data suggest that FMDGTMSQV is naturally processed and presented in vivo, and that this presentation leads to substantial but incomplete self-tolerance. The relevance of this model to an understanding of the human immune response to tyrosinase is discussed. C1 Univ Virginia, Dept Microbiol, Charlottesville, VA 22908 USA. Univ Virginia, Beirne Carter Ctr Immunol Res, Charlottesville, VA 22908 USA. Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. NCI, Surg Branch, NIH, Bethesda, MD 20892 USA. RP Engelhard, VH (reprint author), Univ Virginia, Dept Microbiol, Charlottesville, VA 22908 USA. RI Restifo, Nicholas/A-5713-2008; OI Restifo, Nicholas P./0000-0003-4229-4580 FU Intramural NIH HHS [Z99 CA999999, Z01 BC010763-01]; NCI NIH HHS [CA09109, CA78400, T32 CA009109, R01 CA078400]; NIAID NIH HHS [AI21393, T32 AI007496]; NIGMS NIH HHS [T32 GM007267] NR 66 TC 114 Z9 115 U1 0 U2 3 PU ROCKEFELLER UNIV PRESS PI NEW YORK PA 1114 FIRST AVE, 4TH FL, NEW YORK, NY 10021 USA SN 0022-1007 J9 J EXP MED JI J. Exp. Med. PD APR 3 PY 2000 VL 191 IS 7 BP 1221 EP 1231 DI 10.1084/jem.191.7.1221 PG 11 WC Immunology; Medicine, Research & Experimental SC Immunology; Research & Experimental Medicine GA 302KX UT WOS:000086365200013 PM 10748239 ER PT J AU Berman, GP Campbell, DK Doolen, GD Nagaev, KE AF Berman, GP Campbell, DK Doolen, GD Nagaev, KE TI Dynamics of nuclear spin measurement in a mesoscopic solid-state quantum computer SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article AB We study numerically the process of nuclear spin measurement in a solid-state quantum computer of the type proposed by Kane, by calculating the quantum dynamics of two coupled nuclear spins on P-31 donors implanted in Si-28. We estimate the time of the 'quantum swap operation'-the minimum measurement time required for the reliable transfer of quantum information from the nuclear spin subsystem to the electronic subsystem. Our calculations show that for realistic values of the parameters this time is of the order of tau(swap) similar to 5 x 10(-5) s. We also calculate the probability of error for typical values of the external noise. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, CNLS, Los Alamos, NM 87545 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Russian Acad Sci, Inst Radioengn & Elect, Moscow 103907, Russia. RP Berman, GP (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, POB 1663, Los Alamos, NM 87545 USA. RI Nagaev, Kirill/H-6802-2016 OI Nagaev, Kirill/0000-0002-1659-6115 NR 7 TC 6 Z9 6 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD APR 3 PY 2000 VL 12 IS 13 BP 2945 EP 2952 DI 10.1088/0953-8984/12/13/306 PG 8 WC Physics, Condensed Matter SC Physics GA 303HF UT WOS:000086415900011 ER PT J AU Gaillard, MK Nelson, BD AF Gaillard, MK Nelson, BD TI Constraints on hidden sector gaugino condensation SO NUCLEAR PHYSICS B LA English DT Article DE gaugino condensation; gaugino masses; supersymmetry breaking ID EFFECTIVE LAGRANGIAN ANALYSIS; SUPERSYMMETRIC STANDARD MODEL; COUPLING-CONSTANT UNIFICATION; STRING THEORY; RENORMALIZATION-GROUP; LOOP CORRECTIONS; SOFT TERMS; SUPERGRAVITY; BREAKING; MATTER AB We study the phenomenology of a class of models describing modular invariant gaugino condensation in the hidden sector of a low-energy effective theory derived from the heterotic string. Placing simple demands on the resulting observable sector, such as a supersymmetry-breaking scale of approximately 1 TeV, a vacuum with properly broken electroweak symmetry, superpartner masses above current direct search limits, etc., results in significant restrictions on the possible configurations of the hidden sector. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. NR 60 TC 35 Z9 35 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 EI 1873-1562 J9 NUCL PHYS B JI Nucl. Phys. B PD APR 3 PY 2000 VL 571 IS 1-2 BP 3 EP 25 DI 10.1016/S0550-3213(99)00811-1 PG 23 WC Physics, Particles & Fields SC Physics GA 303MD UT WOS:000086424900001 ER PT J AU Del Duca, V Dixon, L Maltoni, F AF Del Duca, V Dixon, L Maltoni, F TI New color decompositions for gauge amplitudes at tree and loop level SO NUCLEAR PHYSICS B LA English DT Article DE color decompositions; perturbative QCD ID MULTI-GLUON SCATTERING; YANG-MILLS THEORY; PARKE-TAYLOR; QCD AB Recently, a color decomposition using structure constants was introduced for purely gluonic tree amplitudes, in a compact form involving only the linearly independent subamplitudes. We give two proofs that this decomposition holds for an arbitrary number of gluons, We also present and prove similar decompositions at one loop, both for purl gluon amplitudes and for amplitudes with an external quark-antiquark pair. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Ist Nazl Fis Nucl, Sezione Torino, I-10125 Turin, Italy. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Univ Turin, Dipartimento Fis Teor, I-10125 Turin, Italy. RP Del Duca, V (reprint author), Ist Nazl Fis Nucl, Sezione Torino, Via P Giuria 1, I-10125 Turin, Italy. RI del duca, vittorio/F-6992-2012 NR 25 TC 150 Z9 150 U1 0 U2 1 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 APR 3 PY 2000 VL 571 IS 1-2 BP 51 EP 70 DI 10.1016/S0550-3213(99)00809-3 PG 20 WC Physics, Particles & Fields SC Physics GA 303MD UT WOS:000086424900003 ER PT J AU Astrom, JA Holian, BL Timonen, J AF Astrom, JA Holian, BL Timonen, J TI Universality in fragmentation SO PHYSICAL REVIEW LETTERS LA English DT Article ID DYNAMIC FRAGMENTATION AB Fragmentation of a two-dimensional brittle solid by impact and "explosion," and a fluid by "explosion" are all shown to become critical. Thr critical points appear at a nonzero impact velocity, and at infinite explosion duration, respectively. Within the critical regimes, the fragment-size distributions satisfy a scaling form qualitatively similar to that of the cluster-size distribution of percolation, but they belong to another universality class. Energy balance arguments give a correlation length exponent that is exactly one-half of its percolation value. A single crack dominates fragmentation in the slow-fracture limit, as expected. C1 Univ Jyvaskyla, Dept Phys, FIN-40351 Jyvaskyla, Finland. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Astrom, JA (reprint author), Univ Jyvaskyla, Dept Phys, POB 35, FIN-40351 Jyvaskyla, Finland. NR 15 TC 63 Z9 64 U1 0 U2 10 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 3 PY 2000 VL 84 IS 14 BP 3061 EP 3064 DI 10.1103/PhysRevLett.84.3061 PG 4 WC Physics, Multidisciplinary SC Physics GA 300GD UT WOS:000086243800010 ER PT J AU Esarey, E Schroeder, CB Shadwick, BA Wurtele, JS Leemans, WP AF Esarey, E Schroeder, CB Shadwick, BA Wurtele, JS Leemans, WP TI Nonlinear theory of nonparaxial laser pulse propagation in plasma channels SO PHYSICAL REVIEW LETTERS LA English DT Article ID SELF-MODULATION; TENUOUS PLASMAS; WAVE-GUIDE; INTENSE; RAMAN; SCATTERING; ACCELERATOR; GENERATION AB Nonparaxial propagation of ultrashort, high-power laser pulses in plasma channels is examined. In the adiabatic limit, pulse energy conservation, nonlinear group velocity, damped betatron oscillations, self-steepening, self-phase modulation, and shock formation are analyzed. In the nonadiabatic limit, the coupling of forward Raman scattering (FRS) and the self-modulation instability (SMI) is analyzed and growth rates are derived, including regimes of reduced growth. The SMI is found to dominate FRS in most regimes of interest. C1 Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Ctr Beam Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RP Esarey, E (reprint author), Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Ctr Beam Phys, Berkeley, CA 94720 USA. RI wurtele, Jonathan/J-6278-2016; OI wurtele, Jonathan/0000-0001-8401-0297; Schroeder, Carl/0000-0002-9610-0166 NR 30 TC 78 Z9 78 U1 3 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 APR 3 PY 2000 VL 84 IS 14 BP 3081 EP 3084 DI 10.1103/PhysRevLett.84.3081 PG 4 WC Physics, Multidisciplinary SC Physics GA 300GD UT WOS:000086243800015 ER PT J AU Fuchs, J Labaune, C Depierreux, S Baldis, HA Michard, A AF Fuchs, J Labaune, C Depierreux, S Baldis, HA Michard, A TI Modification of spatial and temporal gains of stimulated Brillouin and Raman scattering by polarization smoothing SO PHYSICAL REVIEW LETTERS LA English DT Article ID SCALE-LENGTH PLASMAS; RANDOM-PHASE PLATE; SUPPRESSION; SPECKLES; INSTABILITY; WAVES AB Significant reductions of stimulated Brillouin (SBS) and Raman (SRS) scattering are measured by adding polarization smoothing (PS) to a random phase plate smoothed beam. The associated plasma waves, as measured by Thomson scattering, are spatially and temporally modified and reveal that the interplay between SBS and SRS has to be taken into account to understand the effect of the smoothing. The results also support the numerical simulations [S. Huller et al., Phys, Plasmas 5, 2706 (1998); R. Berger et al., Phys. Plasmas 6, 1043 (1999)] predicting a reduction of self-focusing with PS, resulting in a decrease of the maximum laser intensity and consequently of SBS and SRS gains. C1 Univ Paris 06, Ecole Polytech, CEA,Lab Utilisat Lasers Intenses, CNRS,UMR 7605, F-91128 Palaiseau, France. Univ Calif Lawrence Livermore Natl Lab, Inst Laser Sci & Applicat, Livermore, CA 94550 USA. RP Fuchs, J (reprint author), Univ Paris 06, Ecole Polytech, CEA,Lab Utilisat Lasers Intenses, CNRS,UMR 7605, F-91128 Palaiseau, France. RI Fuchs, Julien/D-3450-2016 OI Fuchs, Julien/0000-0001-9765-0787 NR 26 TC 23 Z9 24 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 APR 3 PY 2000 VL 84 IS 14 BP 3089 EP 3092 DI 10.1103/PhysRevLett.84.3089 PG 4 WC Physics, Multidisciplinary SC Physics GA 300GD UT WOS:000086243800017 ER PT J AU Strey, HH Wang, J Podgornik, R Rupprecht, A Yu, L Parsegian, VA Sirota, EB AF Strey, HH Wang, J Podgornik, R Rupprecht, A Yu, L Parsegian, VA Sirota, EB TI Refusing to twist: Demonstration of a line hexatic phase in DNA liquid crystals SO PHYSICAL REVIEW LETTERS LA English DT Article ID BOND-ORIENTATIONAL ORDER AB We report conclusive high resolution small angle x-ray scattering evidence that long DNA fragments form an untwisted line hexatic phase between the cholesteric and the crystalline phases. The line hexatic phase is a liquid-crystalline phase with long-range hexagonal bond-orientational order, long-range nematic order, but liquidlike, i.e., short-range, positional order. So far, it has not been seen in any other three dimensional system. By line-shape analysis of x-ray scattering data we found that positional order decreases when the line hexatic phase is compressed. We suggest that such anomalous behavior is a result of the chiral nature of DNA molecules. C1 Univ Massachusetts, Dept Polymer Sci & Engn, Amherst, MA 01003 USA. NICHD, LPSB, NIH, Bethesda, MD 20892 USA. Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. Univ Stockholm, Arrhenius Lab, S-10691 Stockholm, Sweden. NIAMS, LPB, NIH, Bethesda, MD 20892 USA. ExxonMobil Res & Engn Co, Corp Strateg Res, Annandale, NJ 08801 USA. RP Strey, HH (reprint author), Univ Massachusetts, Dept Polymer Sci & Engn, Amherst, MA 01003 USA. RI Sirota, Eric/A-7633-2009; Strey, Helmut/B-5456-2009; Podgornik, Rudolf/C-6209-2008; OI Podgornik, Rudolf/0000-0002-3855-4637; Rupprecht, Allan/0000-0002-2772-1620 NR 18 TC 68 Z9 69 U1 2 U2 13 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 APR 3 PY 2000 VL 84 IS 14 BP 3105 EP 3108 DI 10.1103/PhysRevLett.84.3105 PG 4 WC Physics, Multidisciplinary SC Physics GA 300GD UT WOS:000086243800021 ER PT J AU Bonca, J Katrasnik, T Trugman, SA AF Bonca, J Katrasnik, T Trugman, SA TI Mobile bipolaron SO PHYSICAL REVIEW LETTERS LA English DT Article ID HOLSTEIN-HUBBARD MODEL; SUPERCONDUCTIVITY; POLARONS AB We explore the properties of the bipolaron in a 1D Holstein-Hubbard model with dynamical quantum phonons. Using a recently developed variational method combined with analytical strong coupling calculations, we compute correlation functions, effective mass, bipolaron isotope effect, and the phase diagram. The two site bipolaron has a significantly reduced mass and isotope effect compared to the on-site bipolaron, and is bound in the strong coupling regime up to twice the Hubbard U naively expected. The model can be described in this regime as an effective t-J-V model with nearest neighbor repulsion. These are the most accurate bipolaron calculations to date. C1 Univ Ljubljana, FMF, Ljubljana 1000, Slovenia. Jozef Stefan Inst, Ljubljana 1000, Slovenia. Univ Calif Los Alamos Natl Lab, Div Theory, Los Alamos, NM 87545 USA. RP Bonca, J (reprint author), Univ Ljubljana, FMF, Ljubljana 1000, Slovenia. NR 25 TC 70 Z9 70 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 3 PY 2000 VL 84 IS 14 BP 3153 EP 3156 PG 4 WC Physics, Multidisciplinary SC Physics GA 300GD UT WOS:000086243800033 ER PT J AU Kim, KJ McDonald, KT Stupakov, GV Zolotorev, MS AF Kim, KJ McDonald, KT Stupakov, GV Zolotorev, MS TI Comment on "coherent acceleration by subcycle laser pulses" SO PHYSICAL REVIEW LETTERS LA English DT Article C1 Argonne Natl Lab, Argonne, IL 60439 USA. Princeton Univ, Joseph Henry Labs, Princeton, NJ 08544 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Lawrence Berkeley Natl Lab, Ctr Beam Phys, Berkeley, CA 94720 USA. RP Kim, KJ (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 6 TC 13 Z9 13 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 3 PY 2000 VL 84 IS 14 BP 3210 EP 3210 DI 10.1103/PhysRevLett.84.3210 PG 1 WC Physics, Multidisciplinary SC Physics GA 300GD UT WOS:000086243800048 ER PT J AU Hempel, A Camerman, N Dauter, Z Mastropaolo, D Camerman, A AF Hempel, A Camerman, N Dauter, Z Mastropaolo, D Camerman, A TI The antiestrogen [2-(4-benzylphenoxy)ethyl]diethylammonium chloride SO ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS LA English DT Article ID INTRACELLULAR HISTAMINE ANTAGONIST; BREAST-CANCER; N,N-DIETHYL-2-<4-(PHENYLMETHYL)PHENOXY>ETHANAMINE-HCL; COMBINATION; CELLS AB The crystal structure of the title compound, C19H22NO+. Cl-(common name: N,N-diethyl-2-[(4-phenylmethyl)phenoxy]-ethanamine hydrochloride), contains one molecule in the asymmetric unit. The planes through the two phenyl rings are roughly perpendicular. Protonation occurs at the N atom, to which the Cl- ion is linked via an N-H ... Cl hydrogen bond. The molecule adopts an eclipsed rather than extended conformation. C1 Univ Toronto, Dept Biochem, Toronto, ON M5S 1A8, Canada. NCI, Frederick, MD 21701 USA. Brookhaven Natl Lab, NSLS, Upton, NY 11973 USA. Ardono Res, Seattle, WA 98115 USA. RP Hempel, A (reprint author), Univ Toronto, Dept Biochem, Med Sci Bldg, Toronto, ON M5S 1A8, Canada. FU NIAID NIH HHS [AI40392] NR 12 TC 1 Z9 1 U1 0 U2 0 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0108-2701 J9 ACTA CRYSTALLOGR C JI Acta Crystallogr. Sect. C-Cryst. Struct. Commun. PD APR PY 2000 VL 56 BP 455 EP 456 PN 4 PG 2 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 311RN UT WOS:000086898800024 PM 10815207 ER PT J AU Bryan, JC Burnett, MN Sachleben, RA AF Bryan, JC Burnett, MN Sachleben, RA TI 1,3,5-Tris(chloromethyl)benzene SO ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS LA English DT Article AB The title compound, C9H9Cl3, is being used as a platform for new tripodal receptors. Two molecules make up the asymmetric unit; weak intermolecular hydrogen bonding is observed between methylene H atoms and the chlorine of an adjacent molecule. There are also C-H ...pi interactions. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Bryan, JC (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0108-2701 J9 ACTA CRYSTALLOGR C JI Acta Crystallogr. Sect. C-Cryst. Struct. Commun. PD APR PY 2000 VL 56 BP E167 EP E167 PN 4 PG 1 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 311RN UT WOS:000086898800078 ER PT J AU Capizzano, AA Schuff, N Amend, DL Tanabe, JL Norman, D Maudsley, AA Jagust, W Chui, HC Fein, G Segal, MR Weiner, MW AF Capizzano, AA Schuff, N Amend, DL Tanabe, JL Norman, D Maudsley, AA Jagust, W Chui, HC Fein, G Segal, MR Weiner, MW TI Subcortical ischemic vascular dementia: Assessment with quantitative MR imaging and H-1 MR spectroscopy SO AMERICAN JOURNAL OF NEURORADIOLOGY LA English DT Article; Proceedings Paper CT 7th Annual ISMRM Meeting CY MAY, 1999 CL PHILADELPHIA, PENNSYLVANIA SP ISMRM ID CEREBRAL BLOOD-FLOW; MAGNETIC-RESONANCE SPECTROSCOPY; N-ACETYL-ASPARTATE; ALZHEIMERS-DISEASE; WHITE-MATTER; BINSWANGERS-DISEASE; THALAMIC STROKE; AXONAL INJURY; HUMAN BRAIN; SEGMENTATION AB BACKGROUND AND PURPOSE: Subcortical ischemic vascular dementia is associated with cortical hypometabolism and hypoperfusion, and this reduced cortical metabolism or blood flow can be detected with functional imaging such as positron emission tomography, The aim of this study was to characterize, by means of MR imaging and H-1 MR spectroscopy, the structural and metabolic brain changes that occur among patients with subcortical ischemic vascular dementia compared with those of elderly control volunteers and patients with Alzheimer's disease. METHODS: Patients with dementia and lacunes (n = 11), cognitive impairment and lacunes (n = 14), and dementia without lacunes (n = 18) and healthy age-matched control volunteers (n = 20) underwent MR imaging and H-1 MR spectroscopy. H-1 MR spectroscopy data were coanalyzed with coregistered segmented MR images to account for atrophy and tissue composition. RESULTS: Compared with healthy control volunteers, patients with dementia and lacunes had 11.74% lower N-acetylaspartate/creatine ratios (NAA/Cr) (P = .007) and 10.25% lower N-acetylaspartate measurements (NAA) in the cerebral cortex (P = .03), In white matter, patients with dementia and lacunes showed a 10.56% NAA/Cr reduction (P = .01) and a 12.64% NAA reduction (P = .04) compared with control subjects. NAA in the frontal cortex was negatively correlated with the volume of white matter signal hyperintensity among patients with cognitive impairment and lacunes (P = .002), Patients with dementia, but not patients with dementia and lacunes, showed a 10.33% NAA/Cr decrease (P = .02) in the hippocampus compared with healthy control volunteers. CONCLUSION: Patients with dementia and lacunes have reduced NAA and NAA/Cr in both cortical and white matter regions. Cortical changes may result from cortical ischemia/infarction, retrograde or trans-synaptic injury (or both) secondary to subcortical neuronal loss, or concurrent Alzheimer's pathologic abnormalities. Cortical derangement may contribute to dementia among patients with subcortical infarction. C1 Dept Vet Affairs Med Ctr, Magnet Resonance Unit 114M, San Francisco, CA 94121 USA. Univ Calif San Francisco, Dept Radiol, San Francisco, CA 94143 USA. Univ Calif San Francisco, Dept Med, San Francisco, CA 94143 USA. Univ Calif San Francisco, Dept Psychiat, San Francisco, CA 94143 USA. Univ Calif San Francisco, Dept Neurol, San Francisco, CA 94143 USA. Univ Calif San Francisco, Div Biostat, San Francisco, CA 94143 USA. Ernest Orlando Lawrence Berkeley Natl Lab, Ctr Funct Imaging, Berkeley, CA USA. Univ So Calif, Rancho Los Amigos Med Ctr, Dept Neurol, Downey, CA 90242 USA. RP Capizzano, AA (reprint author), Dept Vet Affairs Med Ctr, Magnet Resonance Unit 114M, 4150 Clement St, San Francisco, CA 94121 USA. FU NIA NIH HHS [R01 AG010897, P01 AG12435, R01 AG10897, P01 AG012435] NR 59 TC 35 Z9 42 U1 0 U2 2 PU AMER SOC NEURORADIOLOGY PI OAK BROOK PA 2210 MIDWEST RD, OAK BROOK, IL 60521 USA SN 0195-6108 J9 AM J NEURORADIOL JI Am. J. Neuroradiol. PD APR PY 2000 VL 21 IS 4 BP 621 EP 630 PG 10 WC Clinical Neurology; Neuroimaging; Radiology, Nuclear Medicine & Medical Imaging SC Neurosciences & Neurology; Radiology, Nuclear Medicine & Medical Imaging GA 305EP UT WOS:000086526700004 PM 10782769 ER PT J AU Emmert-Buck, MR Strausberg, RL Krizman, DB Bonaldo, MF Bonner, RF Bostwick, DG Brown, MR Buetow, KH Chuaqui, RF Cole, DA Duray, PH Englert, CR Gillespie, JW Greenhut, S Grouse, L Hillier, LW Katz, KS Klausner, RD Kuznetzov, V Lash, AE Lennon, G Linehan, WM Liotta, LA Marra, MA Munson, PJ Ornstein, DK Prabhu, VV Prange, C Schuler, GD Soares, MB Tolstoshev, CM Vocke, CD Waterston, RH AF Emmert-Buck, MR Strausberg, RL Krizman, DB Bonaldo, MF Bonner, RF Bostwick, DG Brown, MR Buetow, KH Chuaqui, RF Cole, DA Duray, PH Englert, CR Gillespie, JW Greenhut, S Grouse, L Hillier, LW Katz, KS Klausner, RD Kuznetzov, V Lash, AE Lennon, G Linehan, WM Liotta, LA Marra, MA Munson, PJ Ornstein, DK Prabhu, VV Prange, C Schuler, GD Soares, MB Tolstoshev, CM Vocke, CD Waterston, RH TI Molecular profiling of clinical tissue specimens - Feasibility and applications SO AMERICAN JOURNAL OF PATHOLOGY LA English DT Article ID PROSTATIC INTRAEPITHELIAL NEOPLASIA; LASER CAPTURE MICRODISSECTION; GENE-EXPRESSION PATTERNS; MEN1 GENE; SUSCEPTIBILITY LOCUS; SEQUENCE TAGS; ALLELIC LOSS; HUMAN BRAIN; CANCER; IDENTIFICATION C1 NCI, Pathol Lab, NIH, Bethesda, MD 20892 USA. NCI, Pathogenet Unit, NIH, Bethesda, MD 20892 USA. NCI, Canc Genome Anat Project, Off Director, Bethesda, MD 20892 USA. Univ Iowa, Dept Pediat, Iowa City, IA 52242 USA. Univ Iowa, Dept Physiol & Biophys, Iowa City, IA 52242 USA. NICHD, Lab Integrat & Med Biophys, Bethesda, MD USA. Bostwick Labs, Richmond, VA USA. NCI, Lab Populat Genet, Bethesda, MD 20892 USA. Washington Univ, Genome Sequencing Ctr, St Louis, MO USA. Natl Lib Med, Natl Ctr Biotechnol Informat, Bethesda, MD 20894 USA. Univ Calif Lawrence Livermore Natl Lab, Integrated Mol Anal Genomes & Express Consortium, Biol & Biotechnol Res Program, Livermore, CA USA. NCI, Urol Oncol Branch, Bethesda, MD 20892 USA. British Columbia Canc Res Ctr, Genome Sequence Ctr, Vancouver, BC V5Z 1L3, Canada. NIH, Ctr Informat Technol, Math & Stat Comp Lab, Bethesda, MD 20892 USA. RP Emmert-Buck, MR (reprint author), NCI, Pathol Lab, NIH, Bldg 10,Room 2A33,9000 Rockville Pike, Bethesda, MD 20892 USA. RI Bonner, Robert/C-6783-2015; OI Lash, Alex/0000-0003-3787-1590 NR 52 TC 51 Z9 54 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 APR PY 2000 VL 156 IS 4 BP 1109 EP 1115 DI 10.1016/S0002-9440(10)64979-6 PG 7 WC Pathology SC Pathology GA 303GJ UT WOS:000086413900001 PM 10751334 ER PT J AU Rector, DM Richard, CA Staba, RJ Harper, RM AF Rector, DM Richard, CA Staba, RJ Harper, RM TI Sleep states alter ventral medullary surface responses to blood pressure challenges SO AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY LA English DT Article DE optical imaging; rapid eye movement sleep; quiet sleep; cat; baroreceptor reflex ID INFANT-DEATH-SYNDROME; ARCUATE NUCLEUS; STIMULATION; NEURONS; CAT AB Ventral medullary surface (VMS) activity declines during rapid eye movement (REM) sleep, suggesting a potential for reduced VMS responsiveness to blood pressure challenges during that state. We measured VMS neural activity, assessed as changes in reflected 660-nm wavelength light, during presser and depressor challenges within sleep/waking states in five adult, unrestrained, unanesthetized cats and in two control cats. Phenylephrine elevated blood pressure and elicited an initial VMS activity decline and a subsequent rise in VMS activity in all states, although the initial decline during quiet sleep occurred only in rostral placements. Phasic REM periods elicited a momentary recovery from the evoked activity rise, and arousals diminished the overall elevation in activity. A sodium nitroprusside depressor challenge increased VMS activity more in REM sleep than in quiet sleep, with the increase being even less in waking. Enhanced responses to depressor challenges during REM sleep suggest a loss of dampening of evoked activity during that state; state-related differential baroreflex sensitivity may result from sleep-waking changes in VMS responses to blood pressure challenges. C1 Univ Calif Los Angeles, Dept Neurobiol, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Brain Res Inst, Los Angeles, CA 90095 USA. Univ Calif Irvine, Med Ctr, Dept Neurol, Orange, CA 92868 USA. Univ Calif Los Alamos Natl Lab, Biophys Grp, Los Alamos, NM 87545 USA. RP Harper, RM (reprint author), Univ Calif Los Angeles, Dept Neurobiol, Los Angeles, CA 90095 USA. FU NHLBI NIH HHS [HL22418] NR 33 TC 20 Z9 20 U1 0 U2 0 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0363-6119 J9 AM J PHYSIOL-REG I JI Am. J. Physiol.-Regul. Integr. Comp. Physiol. PD APR PY 2000 VL 278 IS 4 BP R1090 EP R1098 PG 9 WC Physiology SC Physiology GA 304JA UT WOS:000086478900035 PM 10749799 ER PT J AU Zhang, CX Xiang, F Pasa-Tolic, L Anderson, GA Veenstra, TD Smith, RD AF Zhang, CX Xiang, F Pasa-Tolic, L Anderson, GA Veenstra, TD Smith, RD TI Stepwise mobilization of focused proteins in capillary isoelectric focusing mass spectrometry SO ANALYTICAL CHEMISTRY LA English DT Article ID ELECTROOSMOTIC ZONE DISPLACEMENT; UNCOATED CAPILLARIES; MICRODIALYSIS; PERFORMANCE; BEHAVIOR; FLOW AB A stepwise mobilization strategy has been developed for the elution of complex protein mixtures, separated by capillary isoelectric focusing (CIEF) for detection using on line electrospray ionization mass spectrometry (ESI-MS). Carrier polyampholytes are used to establish a pH gradient as well as to control the electroosmotic flow arising from the use of uncoated fused-silica capillaries, Elution of focused protein zones is achieved by controlling the mobilization pressure and voltage, leaving the remaining protein zones focused inside the capillary. Protein zones are stepwise eluted from the capillary by changing the mobilization conditions. Stepwise mobilization improves separation resolution and simplifies coupling with multistage MS (i.e., MSn) analysis since it allows more effective temporal control of protein elution from the CIEF capillary. We also describe a modified configuration for coupling CIEF with ESI-MS using a coaxial sheath flow interface that facilitate the automation of on-line CIEF-ESI-MS analyses. The stepwise mobilization strategy is demonstrated for the analysis of standard protein mixtures and soluble E, coli lysate proteins using CIEF-ESI-MS. These results indicate that inlet pressure or voltage programming to control the elution of the protein zones from the capillary (i,e., gradient mobilization) may allow for the optimization of the mobilization conditions and provide higher resolution for CIEF separation of complex mixtures with on-line MS. C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Smith, RD (reprint author), Pacific NW 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 36 TC 36 Z9 39 U1 0 U2 11 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 APR 1 PY 2000 VL 72 IS 7 BP 1462 EP 1468 DI 10.1021/ac9912653 PG 7 WC Chemistry, Analytical SC Chemistry GA 299YF UT WOS:000086225500023 PM 10763241 ER PT J AU Miyabe, K Guiochon, G AF Miyabe, K Guiochon, G TI Restricted diffusion model for surface diffusion in reversed-phase liquid chromatography SO ANALYTICAL CHEMISTRY LA English DT Article ID OCTADECYLSILYL-SILICA GEL; DILUTE AQUEOUS-SOLUTIONS; LATERAL DIFFUSION; ACTIVATED CARBON; HOMOLOGOUS SERIES; FILLED PORES; ADSORPTION; COEFFICIENT; METHANOL/WATER; INTERFACE AB The analysis of experimental results in reversed-phase liquid chromatography (RPLC) allows further discussion of the restricted diffusion model of surface diffusion formulated on the basis of the absolute rate theory. Chromatographic data were acquired on different RPLC systems with two series of homologous compounds, several stationary phases having different alkyl ligand densities and ligands of various lengths, and methanol/ water mobile phases of different compositions, The enthalpy-entropy compensation observed and the linear free energy relationships found for surface diffusion suggest that the surface diffusion mechanism remains probably the same in all RPLC conditions studied, Whereas the isosteric heat of adsorption approaches zero with decreasing retention, the activation energy of surface diffusion tends toward a finite limit and the surface diffusion coefficient tends toward a value near the corresponding molecular diffusivity. These results support the validity of the restricted diffusion model. The influence of different factors on the validity of this model (i.e., the activation energy and the frequency factor of surface diffusion, and the surface tortuosity) was also considered. 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 47 TC 41 Z9 41 U1 1 U2 6 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 APR 1 PY 2000 VL 72 IS 7 BP 1475 EP 1489 DI 10.1021/ac9909913 PG 15 WC Chemistry, Analytical SC Chemistry GA 299YF UT WOS:000086225500025 ER PT J AU Quinones, I Ford, JA Guiochon, G AF Quinones, I Ford, JA Guiochon, G TI High concentration band profiles and system peaks for a ternary salute system SO ANALYTICAL CHEMISTRY LA English DT Article ID ELUTION PROFILES; LIQUID-CHROMATOGRAPHY; NONLINEAR CHROMATOGRAPHY; BINARY ELUENT; MOBILE-PHASE; ADSORPTION AB High-concentration HPLC band profiles of single solutes and the individual band profiles of the components of binary and ternary mixtures are reported for benzyl alcohol, 2-phenylethanol, and 2-methylbenzyl alcohol. These solutes were eluted from a C-18 column by a binary mobile phase (MeOH:H2O = 1:1, v/v), High-concentration system peaks were obtained using mixtures of benzyl alcohol and 2-phenylethanol at different relative concentrations as the feed and 2-methylbenzyl alcohol as the strong mobile phase additive. Band profiles and system peak profiles were calculated using the equilibrium-dispersive model of chromatography. The adsorption equilibrium in the multicomponent system was characterized by the competitive Langmuir model. Excellent quantitative agreement was found between the experimental and the calculated profiles. This work confirms that extremely unusual system peak profiles can be obtained even when the adsorption behavior is quite simple. Under certain circumstances, the use of a properly chosen additive could markedly increase the separation between bands and hence the production rate, the recovery yield, and/or the purity of the fractions. C1 Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Univ Tennessee, Dept Chem Engn, 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 24 TC 12 Z9 12 U1 0 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 APR 1 PY 2000 VL 72 IS 7 BP 1495 EP 1502 DI 10.1021/ac9909406 PG 8 WC Chemistry, Analytical SC Chemistry GA 299YF UT WOS:000086225500027 ER PT J AU Patel, SV Jenkins, MW Hughes, RC Yelton, WG Ricco, AJ AF Patel, SV Jenkins, MW Hughes, RC Yelton, WG Ricco, AJ TI Differentiation of chemical components in a binary solvent vapor mixture using carbon/polymer composite-based chemiresistors SO ANALYTICAL CHEMISTRY LA English DT Article ID CONDUCTOR-INSULATOR COMPOSITE; PATTERN-RECOGNITION; POLYMER; ARRAY; TEMPERATURE; RESPONSES; SENSORS AB We demonstrate a "universal solvent sensor" constructed from a small array of carbon/polymer composite chemi-resistors that respond to solvents spanning a wide range of Hildebrand solubility parameters. Conductive carbon particles provide electrical continuity in these composite films. When the polymer matrix absorbs soh ent vapors, the composite film swells the average separation between carbon particles increases, and an increase in him resistance results, as some of the conduction pathways are broken. The adverse effects of contact resistance at high solvent concentrations are reported. Solvent vapors including isooctane, ethanol, diisopropylmethylphosphonate (DIMP), and water are correctly identified ("classified") using three chemiresistors, their composite coatings chosen to span the full range of solubility parameters. With the same three sensors, binary mixtures of solvent vapor and water vapor are correctly classified; following classification, two sensors suffice to determine the concentrations of both vapor components. Poly(ethylene-vinyl acetate) and poly(vinyl alcohol) (PVA) are two such polymers that are used to classify binary mixtures of DIMP with water vapor; the PVA/carbon particle composite films are sensitive to less than 0.25% relative humidity. The Sandia-developed visual-empirical region of influence (VERI) technique is used as a method of pattern recognition to classify the solvents and mixtures and to distinguish them from Rater vapor. In many cases, the response of a given composite sensing film to a binary mixture deviates significantly from the sum of the responses to the isolated vapor components at the same concentrations. While these nonlinearities pose significant difficulty for (primarily) linear methods such as principal component analysis, VERI handles both linear and nonlinear data with equal ease. In the present study, the maximum speciation accuracy is achieved by an array containing three or four sensor elements, with the addition of more sensors resulting in a measurable accuracy decrease. C1 Sandia Natl Labs, Microsensor Res & Dev Dept, Albuquerque, NM 87185 USA. RP Patel, SV (reprint author), ACLARA Biosci, 1288 Pear Ave, Mt View, CA 94043 USA. RI Ricco, Antonio/A-5273-2010; Patel, Sanjay/D-2903-2014; OI Patel, Sanjay/0000-0001-9540-9957; Ricco, Antonio/0000-0002-2355-4984 NR 23 TC 60 Z9 62 U1 0 U2 10 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 APR 1 PY 2000 VL 72 IS 7 BP 1532 EP 1542 DI 10.1021/ac990830z PG 11 WC Chemistry, Analytical SC Chemistry GA 299YF UT WOS:000086225500032 ER PT J AU Peng, TZ Chen, Q Stevens, RC AF Peng, TZ Chen, Q Stevens, RC TI Amperometric detection of Escherichia coli heat labile enterotoxin by redox diacetylenic vesicles on a sol-gel thin film electrode SO ANALYTICAL CHEMISTRY LA English DT Article ID LATERAL CHARGE TRANSPORT; ALUMINUM-OXIDE FILMS; COLORIMETRIC DETECTION; TRANSLATIONAL DIFFUSION; MOLECULAR RECOGNITION; BILAYER ASSEMBLIES; CHOLERA-TOXIN; ENZYME; POLYMER; BIOSENSORS AB Supramolecular assemblies (bilayer vesicles) prepared from ferrocenic diacetylene lipid and the cell surface receptor ganglioside GM1 are utilized to construct an amperometric biosensor for Escherichia coli heat-labile enterotoxin on a sol-gel thin-film electrode. The bilayer vesicles adsorbed on the sol-gel film provide an open platform for molecular recognition, while the electro-chemical communication between the incorporated redox lipids and the electrode is influenced by the binding of the toxin. Cyclic voltammetric studies suggest a facile redox reaction for the adsorbed supramolecular assembly, which allows the sensor to detect enterotoxin up to 3 ppm (3.6 x 10(-8) M) concentration. The apparent diffusion coefficients for the redox lipids in the assembly were observed to be in the range of 4.73 x 10(-8)-2.30 x 10(-8) cm/s(2). A mechanism of lateral electron transport of redox lipids controlled by biomolecular recognition is proposed. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Chem, Berkeley, CA 94720 USA. Hangzhou Univ, Dept Chem, Hangzhou 310028, Peoples R China. RP Stevens, RC (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Stevens, Raymond/K-7272-2015 OI Stevens, Raymond/0000-0002-4522-8725 NR 41 TC 45 Z9 47 U1 0 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 APR 1 PY 2000 VL 72 IS 7 BP 1611 EP 1617 DI 10.1021/ac990406y PG 7 WC Chemistry, Analytical SC Chemistry GA 299YF UT WOS:000086225500042 PM 10763260 ER PT J AU Duan, YX Su, YX Jin, Z Abeln, SP AF Duan, YX Su, YX Jin, Z Abeln, SP TI A field portable plasma source monitor for real-time air particulate monitoring SO ANALYTICAL CHEMISTRY LA English DT Article ID ATOMIC-EMISSION-SPECTROMETRY; INDUCED BREAKDOWN SPECTROSCOPY; MICROWAVE PLASMA; MASS-SPECTROMETRY; ANALYTICAL PERFORMANCE; ATMOSPHERIC-PRESSURE; TORCH; METALS; MATTER; ARGON AB In this research, a novel portable instrument for on-site, real-time air particulate monitoring nas developed. It is highly desirable to use microwave plasmas for on-site, real-time environmental and occupational hazard monitoring because they can be sustained with various gases at relatively low power and possess excellent detection capabilities for both metal and nonmetal air pollutants. In the new instrument design, a microwave plasma was selected as an excitation source and was used in conjunction with atomic emission spectrometry A small, integrated spectrometer with a charge-coupled detector (CCD) was used for optical signal detection. An efficient, in situ air-sampling system was developed for direct sampling of air particles into the plasma. Characterization and calibration of the new instrument were achieved with an in-house-fabricated high-efficiency nebulization-desolvation system. Tolerance of the microwave argon plasma source to air introduction was tested, and the operational parameters were optimized. Analytical performance and the feasibility of the newly developed portable instrument for aerosol particle analysis were evaluated. Some advantages and possible applications of the new instrument are discussed. The instrument provides an innovative tool for rapid environmental and occupational hazard monitoring. C1 Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Duan, YX (reprint author), Los Alamos Natl Lab, Chem Sci & Technol Div, CST-9,MS K484, Los Alamos, NM 87545 USA. EM yduan@lanl.gov NR 47 TC 41 Z9 43 U1 1 U2 12 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 APR 1 PY 2000 VL 72 IS 7 BP 1672 EP 1679 DI 10.1021/ac991237k PG 8 WC Chemistry, Analytical SC Chemistry GA 299YF UT WOS:000086225500050 ER PT J AU Khericha, ST AF Khericha, ST TI Development of one-energy group, two-dimensional, frequency dependent detector adjoint function based on the nodal method SO ANNALS OF NUCLEAR ENERGY LA English DT Article ID NEUTRON NOISE DIAGNOSTICS; CONTROL ROD VIBRATIONS; MODEL AB One-energy group, two-dimensional computer code was developed to calculate the response of a detector to a vibrating absorber in a reactor core. A concept of local/global components, based on the frequency dependent detector adjoint function, and a nodalization technique were utilized. The frequency dependent detector adjoint functions presented by complex equations were expanded into real and imaginary parts. In the nodalization technique, the flux is expanded into polynomials about the center point of each node. The phase angle and the magnitude of the one-energy group detector adjoint function were calculated for a detector located in the center of a 200 x 200 cm reactor using a two-dimensional nodalization technique, the computer code EXTERMINATOR, and the analytical solution. The purpose of this research was to investigate the applicability of a polynomial nodal model technique to the calculations of the real and the imaginary parts of the detector adjoint function for one-energy group two-dimensional polynomial nodal model technique. From the results as discussed earlier, it is concluded that the nodal model technique can be used to calculate the detector adjoint function and the phase angle. Using the computer code developed for nodal model technique, the magnitude of one energy group frequency dependent detector adjoint function and the phase angle were calculated for the detector located in the center of a 200 x 200 cm homogenous reactor. The real part of the detector adjoint function was compared with the results obtained from the EXTERMINATOR computer code as well as the analytical solution based on a double sine series expansion using the classical Green's Function solution. The values were found to be less than 1% greater at 20 cm away from the source region and about 3% greater closer to the source compared to the values obtained from the analytical solution and the EXTERMINATOR code. The currents at the node interface matched within 1% of the average value at the interface. The phase angle varied from 0.1 degrees to 0.4 degrees compared to 0.2 degrees calculated using the point reactor zero power transfer function. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Lockheed Martin Idaho Technol Co, Idaho Falls, ID 83415 USA. RP Khericha, ST (reprint author), Lockheed Martin Idaho Technol Co, MS 3850,POB 1625, Idaho Falls, ID 83415 USA. NR 29 TC 0 Z9 0 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0306-4549 J9 ANN NUCL ENERGY JI Ann. Nucl. Energy PD APR PY 2000 VL 27 IS 6 BP 465 EP 482 DI 10.1016/S0306-4549(99)00066-3 PG 18 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 282XE UT WOS:000085246400001 ER PT J AU Courant, ED Snyder, HS AF Courant, ED Snyder, HS TI Theory of the alternating-gradient synchrotron (Reprinted from Annals of Physics, vol 3, pg 1-48, 1958) SO ANNALS OF PHYSICS LA English DT Reprint AB The equations of motion of the particles in a synchrotron in which the field gradient index n = - (r/b)partial derivative B/partial derivative r varies along the equilibrium orbit are examined on the basis of the linear approximation. It is shown that if n alternates rapidly between large positive and large negative values, the stability of both radial and vertical oscillations can be greatly increased compared to conventional accelerators in which ir is azimuthally constant and must lie between 0 and 1. Thus aperture requirements are reduced. For practical designs. the improvement is limited by the effects of constructional errors. these lead to resonance excitation of oscillations and consequent instability if 2v(x), or 2v(x), or v(x) + v(z) is integral, where v(x) and v(z) the frequencies of horizontal and vertical betatron oscillations. measured in units of the fnqucncy of revolution. The mechanism of phase stability is essentially the same as in a conventional synchrotron. but the radial amplitude of synchrotron oscillations is reduced substantially. Furthermore, at a "transition energy" E-1 approximate to v(x)Mc(2) the stable and unstable equilibrium phases exchange roles. necessitating a jump in the phase of the radiofrequency accelerating voltage. Calculations indicate that the manner in which this jump is performed is not very critical. (C) 1958 Academic Press. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. RP Courant, ED (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. NR 27 TC 15 Z9 15 U1 0 U2 3 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0003-4916 J9 ANN PHYS-NEW YORK JI Ann. Phys. PD APR-MAY PY 2000 VL 281 IS 1-2 BP 360 EP 408 DI 10.1006/aphy.2000.6012 PG 49 WC Physics, Multidisciplinary SC Physics GA 313CP UT WOS:000086983000007 ER PT J AU Drell, SD Yan, TM AF Drell, SD Yan, TM TI Partons and their applications at high energies (Reprinted from Annals of Physics, vol 66, pg 578-623, 1971) SO ANNALS OF PHYSICS LA English DT Reprint ID PAIR ANNIHILATION PROCESSES; LEPTON-NUCLEON SCATTERING AB This paper is dedicated to the memory of Amos de-Shalit with deep sadness at the loss. not only of a very distinguished and important scientific colleague but also of a very close personal friend whose gentleness was matched only by his wisdom. In his tragically brief life by persistently strove to bridge the growing gulfs between different scientific disciplines as also between different cultures and nations. Of special physical interest to him was the unity of concepts in nuclear and particle physics an example of which is presented here in the form of the impulse approximation. S.D.D. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94305 USA. RP Drell, SD (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94305 USA. NR 25 TC 8 Z9 8 U1 0 U2 0 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0003-4916 J9 ANN PHYS-NEW YORK JI Ann. Phys. PD APR-MAY PY 2000 VL 281 IS 1-2 BP 450 EP 493 DI 10.1006/aphy.2000.6014 PG 44 WC Physics, Multidisciplinary SC Physics GA 313CP UT WOS:000086983000010 ER PT J AU Ford, KW Wheeler, JA AF Ford, KW Wheeler, JA TI Semiclassical description of scattering (Reprinted from Annals of Physics, vol 7, pg 259-286, 1959) SO ANNALS OF PHYSICS LA English DT Reprint AB The quantum-mechanical scattering amplitude can be simply related to the classical deflection function when the conditions for a semiclassical analysis of the quantum-mechanical scattering are met. Various interesting characteristic features of the scattering are related to special features of the classical deflection function. The characteristic types of scattering discussed are: interference. when the deflection function possesses more th:ln one branch at a given angle: rainbow scattering, when the deflection function has a relative maximum or minimum; glory scattering, when the deflection function passes smoothly through 0 degrees or through an integral multiple of +/- pi: and orbiting, when the deflection function possesses a singularity. The consideration of the characteristic features of semiclassical scattering makes possible the analysis of an observed differential cross section to yield the classical deflection function, which in turn may be used to construct the potential. (C) 1959 Academic Press. C1 Los Alamos Sci Lab, Los Alamos, NM USA. Indiana Univ, Bloomington, IN USA. Princeton Univ, Palmer Phys Lab, Princeton, NJ 08544 USA. RP Ford, KW (reprint author), Brandeis Univ, Dept Phys, Waltham, MA 02254 USA. NR 21 TC 2 Z9 2 U1 2 U2 6 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0003-4916 EI 1096-035X J9 ANN PHYS-NEW YORK JI Ann. Phys. PD APR-MAY PY 2000 VL 281 IS 1-2 BP 608 EP 635 DI 10.1006/aphy.2000.6018 PG 28 WC Physics, Multidisciplinary SC Physics GA 313CP UT WOS:000086983000014 ER PT J AU Jacob, M Wick, GC AF Jacob, M Wick, GC TI On the general theory of collisions for particles with spin (Reprinted from Annals of Physics, vol 7, pg 404-428, 1959) SO ANNALS OF PHYSICS LA English DT Reprint AB The general analysis of binary reactions involving particles with arbitrary spin is reformulated in such a way, that it applies equally well to relativistic particles (including photons). This is achieved by using longitudinal spin components ("helicity states") not only in the initial and final states, but also in the angular momentum states which are employed as usual to reduce the S-matrix to a simpler form. Expressions for the scattering and reaction-amplitude, intensity and polarization are given. They involve fewer vector-addition coefficients than the customary formulas, and no recoupling coefficients. The application to some examples is sketched, and in the Appendix some formulas are given that may be of use in the applications. (C) 1959 Academic Press. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. RP Jacob, M (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. NR 23 TC 100 Z9 100 U1 1 U2 2 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0003-4916 J9 ANN PHYS-NEW YORK JI Ann. Phys. PD APR-MAY PY 2000 VL 281 IS 1-2 BP 774 EP 799 DI 10.1006/aphy.2000.6022 PG 26 WC Physics, Multidisciplinary SC Physics GA 313CP UT WOS:000086983000018 ER PT J AU Kerman, AK McManus, H Thaler, RM AF Kerman, AK McManus, H Thaler, RM TI The scattering of fast nucleons from nuclei (Reprinted from Annals of Physics, vol 8, pg 551, 1959) SO ANNALS OF PHYSICS LA English DT Reprint AB The formal theory of the scattering of high-energy nucleons by nuclei is developed in terms of the, nucleon-nucleon scattering amplitude. The most important approximations necessary to make numerical calculation feasible are then examined. The optical model potential is derived on this basis and compared with the optical model parameters found fi om experiment. The elastic scattering and polarization of nucleons From light nuclei is predicted and compared with experiment. The effect of nuclear correlations is discussed. The polarization of inelastically scattered nucleons is discussed and predictions compared with experiments. To within the validity of the approximations the experimental data on the scattering of nucleons from nuclei at energies above similar to 100 Mev appears to he consistent with the theory. (C) 1959 Academic Press. C1 MIT, Cambridge, MA 02139 USA. AECL Res, Chalk River Labs, Chalk River, ON K0J 1J0, Canada. Los Alamos Sci Lab, Los Alamos, NM USA. RP Kerman, AK (reprint author), MIT, 77 Massachusetts Ave, Cambridge, MA 02139 USA. NR 67 TC 0 Z9 0 U1 0 U2 0 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0003-4916 J9 ANN PHYS-NEW YORK JI Ann. Phys. PD APR-MAY PY 2000 VL 281 IS 1-2 BP 853 EP 940 DI 10.1006/aphy.2000.6024 PG 88 WC Physics, Multidisciplinary SC Physics GA 313CP UT WOS:000086983000020 ER PT J AU Friedman, J Hastie, T Tibshirani, R AF Friedman, J Hastie, T Tibshirani, R TI Additive logistic regression: A statistical view of boosting SO ANNALS OF STATISTICS LA English DT Article DE classification; tree; nonparametric estimation; stagewise fitting; machine learning ID CLASSIFICATION AB Boosting is one of the most important recent developments in classification methodology. Boosting works by sequentially applying a classification algorithm to reweighted Versions of the training data and then taking a weighted majority vote of the sequence of classifiers thus produced. For many classification algorithms, this simple strategy results in dramatic improvements in performance. We show that this seemingly mysterious phenomenon can be understood in terms of well-known statistical principles, namely additive modeling and maximum likelihood. For the two-class problem, boosting can be viewed as an approximation to additive modeling on the logistic scale using maximum Bernoulli likelihood as a criterion. We develop more direct approximations and show that they exhibit nearly identical results to boosting. Direct multiclass generalizations based on multinomial likelihood are derived that exhibit performance comparable to other recently proposed multiclass generalizations of boosting in most situations, and far superior in some. We suggest a minor modification to boosting that can reduce computation, often by factors of 10 to 50. Finally, we apply these insights to produce an alternative formulation of boosting decision trees. This approach, based on best-first truncated tree induction, often leads to better performance, and can provide interpretable descriptions of the aggregate decision rule. It is also much faster computationally, making it more suitable to large-scale data mining applications. C1 Stanford Univ, Dept Stat, Stanford, CA 94305 USA. Stanford Linear Accelerator Ctr, Stanford, CA 94305 USA. Stanford Univ, Dept Hlth Res & Policy, Div Biostat, Stanford, CA 94305 USA. RP Stanford Univ, Dept Stat, Sequoia Hall, Stanford, CA 94305 USA. EM jnf@stat.stanford.edu; hastie@stat.stanford.edu; tibs@stat.stanford.edu RI anzhi, yue/A-8609-2012 NR 29 TC 2001 Z9 2099 U1 28 U2 243 PU INST MATHEMATICAL STATISTICS PI CLEVELAND PA 3163 SOMERSET DR, CLEVELAND, OH 44122 USA SN 0090-5364 J9 ANN STAT JI Ann. Stat. PD APR PY 2000 VL 28 IS 2 BP 337 EP 374 DI 10.1214/aos/1016218223 PG 38 WC Statistics & Probability SC Mathematics GA 360LT UT WOS:000089669700001 ER PT J AU Vanderberg, LA Krieger-Grumbine, R Taylor, MN AF Vanderberg, LA Krieger-Grumbine, R Taylor, MN TI Evidence for diverse oxidations in the catabolism of toluene by Rhodococcos rhodochrous strain OFS SO APPLIED MICROBIOLOGY AND BIOTECHNOLOGY LA English DT Article ID PSEUDOMONAS-PUTIDA; GENUS RHODOCOCCUS; METABOLISM; BIODEGRADATION; PATHWAY AB Rhodococcus rhodochrous strain OFS grew on toluene as a sole source of carbon and energy with a maximum growth rate of 0.011 h(-1). Initial reaction products were extracted, derivatized and identified by GC-MS. Oxygen consumption studies indicated that OFS grown on an aliphatic substrate required an induction period before oxidizing toluene. OFS grown on toluene transformed an array of aromatic ground water pollutants including styrene, ethylbenzene and chlorobenzene. Products of these transformations were identified. The sole product of chlorobenzene biotransformation was 4-chlorophenol. Products from toluene oxidation included 3- and 4-methylcatechol as well as benzyl alcohol, p-cresol and cis-toluene dihydrodiol. The identification of these and the products of other aromatic substrate conversions affirm that oxidation occurred on the functional group as well as directly on the aromatic nucleus. C1 Univ Calif Los Alamos Natl Lab, Biosci Div, Los Alamos, NM 87545 USA. RP Vanderberg, LA (reprint author), Univ Calif Los Alamos Natl Lab, Biosci Div, B South,Mailstop E-529, Los Alamos, NM 87545 USA. NR 19 TC 12 Z9 12 U1 1 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0175-7598 J9 APPL MICROBIOL BIOT JI Appl. Microbiol. Biotechnol. PD APR PY 2000 VL 53 IS 4 BP 447 EP 452 PG 6 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA 312XT UT WOS:000086969800014 PM 10803902 ER PT J AU Mirkarimi, PB Bajt, S Wall, MA AF Mirkarimi, PB Bajt, S Wall, MA TI Mo/Si and Mo/Be multilayer thin films on Zerodur substrates for extreme-ultraviolet lithography SO APPLIED OPTICS LA English DT Article ID X-RAY-SCATTERING; INTERFACIAL ROUGHNESS; IMAGING-SYSTEM; MIRRORS; FABRICATION; COATINGS AB Multilayer-coated Zerodur optics are expected to play a pivotal role in an extreme-ultraviolet (EUV) lithography tool. Zerodur is a multiphase, multicomponent material that is a much more complicated substrate than commonly used single-crystal Si or fused-silica substrates. We investigate the effect of Zerodur substrates on the performance of high-EUV reflectance Mo/Si and Mo/Be multilayer thin films. For Mo/Si the EUV reflectance had a nearly linear dependence on substrate roughness for roughness values of 0.06-0.36 nm rms, and the FWHM of the reflectance curves (spectral bandwidth) was essentially constant over this range. For Mo/Be the EUV reflectance was observed to decrease more steeply than Mo/Si for roughness values greater than approximately 0.2-0.3 nm. Little difference was observed in the EUV reflectivity of multilayer thin films deposited on different substrates as long as the substrate roughness values were similar. (C) 2000 Optical Society of America. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Mirkarimi, PB (reprint author), Lawrence Livermore Natl Lab, Mail Stop L 395,7000 E Ave, Livermore, CA 94550 USA. EM mirkarimi1@llnl.gov RI Bajt, Sasa/G-2228-2010 NR 21 TC 33 Z9 34 U1 0 U2 5 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 APR 1 PY 2000 VL 39 IS 10 BP 1617 EP 1625 DI 10.1364/AO.39.001617 PG 9 WC Optics SC Optics GA 299RD UT WOS:000086210900024 PM 18345060 ER PT J AU Her, TH Finlay, RJ Wu, C Mazur, E AF Her, TH Finlay, RJ Wu, C Mazur, E TI Femtosecond laser-induced formation of spikes on silicon SO APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING LA English DT Article AB We find that silicon surfaces develop arrays of sharp conical spikes when irradiated with 500-fs laser pulses in SF6. The height of the spikes decreases with increasing pulse duration or decreasing laser fluence, and scales nonlinearly with the average separation between spikes. The spikes have the same crystallographic orientation as bulk silicon and always point along the incident direction of laser pulses. The base of the spikes has an asymmetric shape and its orientation is determined by the laser polarization. Our data suggest that both laser ablation and laser-induced chemical etching of silicon are involved in the formation of the spikes. C1 Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. Harvard Univ, Dept Phys, Cambridge, MA 02138 USA. RP Her, TH (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, MS 2-300,1 Cyclotron Rd, Berkeley, CA 94720 USA. RI Mazur, Eric/B-8918-2009 NR 18 TC 165 Z9 177 U1 6 U2 40 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 APR PY 2000 VL 70 IS 4 BP 383 EP 385 DI 10.1007/s003390051052 PG 3 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 307HT UT WOS:000086648400003 ER PT J AU Fluck, R Hermann, MR Hackel, LA AF Fluck, R Hermann, MR Hackel, LA TI Energetic and thermal performance of high-gain diode-side-pumped Nd : YAG rods SO APPLIED PHYSICS B-LASERS AND OPTICS LA English DT Article ID HEAT; DENSITIES; LASER AB We investigated the energetic and thermal performance of a diode-side-pumped Nd:YAG rod laser with up to 50 W power deposited as excess heat into a 3-mm-diameter, 10-cm-length rod. The rod design produces an extremely flat gain profile resulting in "textbook" expressions of thermal lensing and birefringence. Thermal and energetic measurements are compared to corresponding "textbook" theoretical expressions. Discrepancies between various published thermo-mechanical YAG parameters are resolved by a self-consistent set of measured and calculated data for rod thermal lens focal lengths, birefringence depolarization and ratio of heat to stored energy (chi). Measured thermal and energetic performance under lasing and nonlasing conditions are presented, which agree with published theoretical expressions and measurements. Compensation of rod thermal lensing with simple spherical concave lenses is demonstrated. In addition various methods for compensating birefringence depolarization are theoretically and experimentally analyzed and compared. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Fluck, R (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-438, Livermore, CA 94550 USA. NR 24 TC 15 Z9 20 U1 1 U2 5 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0946-2171 J9 APPL PHYS B-LASERS O JI Appl. Phys. B-Lasers Opt. PD APR PY 2000 VL 70 IS 4 BP 491 EP 498 DI 10.1007/s003400050851 PG 8 WC Optics; Physics, Applied SC Optics; Physics GA 307HV UT WOS:000086648600006 ER PT J AU Iyer, R Lehnert, BE AF Iyer, R Lehnert, BE TI Effects of ionizing radiation in targeted and nontargeted cells SO ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS LA English DT Review ID TRANSFORMING-GROWTH-FACTOR; SISTER-CHROMATID EXCHANGES; ALPHA-PARTICLE IRRADIATION; DOUBLE STRAND BREAKS; DNA-DAMAGE; HYDROGEN-PEROXIDE; HUMAN-FIBROBLASTS; P53 PROTEIN; CHROMOSOMAL INSTABILITY; OXIDATIVE STRESS C1 Univ Calif Los Alamos Natl Lab, Biosci Div, Los Alamos, NM 87545 USA. RP Lehnert, BE (reprint author), Univ Calif Los Alamos Natl Lab, Biosci Div, Los Alamos, NM 87545 USA. FU NCI NIH HHS [CA82598] NR 151 TC 69 Z9 73 U1 2 U2 4 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0003-9861 J9 ARCH BIOCHEM BIOPHYS JI Arch. Biochem. Biophys. PD APR 1 PY 2000 VL 376 IS 1 BP 14 EP 25 DI 10.1006/abbi.1999.1684 PG 12 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 299JJ UT WOS:000086195100002 PM 10729186 ER PT J AU Crawley, DB Pedersen, CO Lawrie, LK Winkelmann, FC AF Crawley, DB Pedersen, CO Lawrie, LK Winkelmann, FC TI EnergyPlus: Energy simulation program SO ASHRAE JOURNAL LA English DT Article AB Various building energy simulation programs developed around the world are reaching maturity. Many use simulation methods (and even code) that originated in the 1960s. Without substantial redesign and restructuring of the programs, continuing to expand their capabilities has become difficult, time-consuming, and prohibitively expensive. However, phenomenal advances in analysis methods and computational power have increased the opportunity for significant improvements in the flexibility and comprehensiveness of these tools. C1 US DOE, Washington, DC 20585 USA. Lawrence Berkeley Natl Lab, Environm Energy Technol Div, Simulat Res Grp, Berkeley, CA USA. Univ Illinois, Urbana, IL 61801 USA. RP Crawley, DB (reprint author), US DOE, Washington, DC 20585 USA. NR 9 TC 115 Z9 119 U1 3 U2 8 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 APR PY 2000 VL 42 IS 4 BP 49 EP 56 PG 8 WC Thermodynamics; Construction & Building Technology; Engineering, Mechanical SC Thermodynamics; Construction & Building Technology; Engineering GA 301ZZ UT WOS:000086341600015 ER PT J AU Akerlof, C Amrose, S Balsano, R Bloch, J Casperson, D Fletcher, S Gisler, G Hills, J Kehoe, R Lee, B Marshall, S McKay, T Pawl, A Schaefer, J Szymanski, J Wren, J AF Akerlof, C Amrose, S Balsano, R Bloch, J Casperson, D Fletcher, S Gisler, G Hills, J Kehoe, R Lee, B Marshall, S McKay, T Pawl, A Schaefer, J Szymanski, J Wren, J TI ROTSE all-sky surveys for variable stars. I. Test fields SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : structure; RR Lyrae variable; supernovae : general ID HIPPARCOS AB The Robotic Optical Transient Search Experiment I(ROTSE-I) experiment has generated CCD photometry for the entire northern sky in two epochs nightly since 1998 March. These sky patrol data are a powerful resource for studies of astrophysical transients. As a demonstration project, we present first results of a search for periodic variable stars derived from ROTSE-I observations. Variable identification, period determination, and type classification are conducted via automatic algorithms. In a set of nine ROTSE-I sky patrol fields covering roughly 2000 deg(2), we identify 1781 periodic variable stars with mean magnitudes between m(v) = 10.0 and m(v) = 15.5. About 90% of these objects are newly identified as variable. Examples of many familiar types are presented. All classifications for this study have been manually confirmed. The selection criteria for this analysis have been conservatively defined and are known to be biased against some variable classes. This preliminary study includes only 5.6% of the total ROTSE-I sky coverage, suggesting that the full ROTSE-I variable catalog will include more than 32,000 periodic variable stars. C1 Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Akerlof, C (reprint author), Univ Michigan, Dept Phys, 2477 Randall Lab, Ann Arbor, MI 48109 USA. RI McKay, Timothy/C-1501-2009 OI McKay, Timothy/0000-0001-9036-6150 NR 20 TC 131 Z9 131 U1 1 U2 3 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 APR PY 2000 VL 119 IS 4 BP 1901 EP 1913 DI 10.1086/301321 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 304WY UT WOS:000086508100031 ER PT J AU Grupe, D Leighly, KM Thomas, HC Laurent-Muehleisen, SA AF Grupe, D Leighly, KM Thomas, HC Laurent-Muehleisen, SA TI The enigmatic soft X-ray AGN RX J0134.2-4258 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE acceleration of particles; galaxies : active; galaxies : nuclei; galaxies : quasars : individual : RX J0134.2-4258 ID ACTIVE GALACTIC NUCLEI; RADIO-QUIET QUASARS; ALL-SKY SURVEY; SEYFERT-1 GALAXIES; ASCA OBSERVATIONS; ACCRETION DISKS; SOURCE CATALOG; FE-II; LOUD; OUTBURST AB We report the discovery and analysis of the followup ROSAT pointed observation, an ASCA observation and optical and radio observations of the enigmatic soft X-ray AGN RX J0134.2-4258. In the optical, RX J0134.2-4258 appears as an extreme 'Narrow-Line Seyfert 1 galaxy' (NLS1), with very strong Fell emission, very blue optical continuum spectrum and almost no Narrow Line Region emission. While its spectrum was one of the softest observed From an AGN during the ROSAT All-Sky Survey, its spectrum was found to be dramatically harder during a pointed observation although the count rate remained constant. We found in the pointed observation that the spectrum is softer when it is fainter and spectral fitting demonstrates that it is the hard component that is variable. The ASCA observation confirms the presence of a hard X-ray power law, the slope of which is rattler flat compared with other NLS1s. Survey and followup radio observations reveal that RX J0134.2-4258 is also unusual in that it is a member of the rare class of radio-loud NLS Is, and, with R=71, it holds the current record for largest radio-to-optical ratio in NLS1s. We discuss possible scenarios to explain its strange behaviour. C1 MPI Extraterr Phys, D-85748 Garching, Germany. Columbia Astrophys Lab, New York, NY 10027 USA. MPI Astrophys, D-85748 Garching, Germany. Univ Calif Davis, Livermore, CA 94550 USA. IGPP, LLNL, Livermore, CA 94550 USA. RP Grupe, D (reprint author), MPI Extraterr Phys, Giessenbachstr, D-85748 Garching, Germany. EM dgrupe@xray.mpe.mpg.de NR 49 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 APR PY 2000 VL 356 IS 1 BP 11 EP 22 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 311DJ UT WOS:000086869300010 ER PT J AU Lara, L Mack, KH Lacy, M Klein, U Cotton, WD Feretti, L Giovannini, G Murgia, M AF Lara, L Mack, KH Lacy, M Klein, U Cotton, WD Feretti, L Giovannini, G Murgia, M TI The giant radio galaxy 8C 0821+695 and its environment SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : individual : 8C 0821+695; galaxies : active; galaxies : cooling flows; radio continuum : galaxies ID INTERGALACTIC MEDIUM; SKY SURVEY; MULTIFREQUENCY; COCOONS; JET AB We present new VLA and Effelsberg observations of the radio galaxy 8C 0821+695. We have obtained detailed images in total intensity and polarization of this 2 Mpc sized giant. The magnetic field has a configuration predominantly parallel to the source main axis. We observe Faraday rotation at low frequencies, most probably produced by an ionized medium external to the radio source, The spectral index distribution is that typical of FR II radio galaxies, with spectral indices gradually steepening from the source extremes towards the core. Modeling the spectrum in the lobes using standard synchrotron loss models yields the spectral age of the source and the mean velocity of the jet-head with respect to the lobe material. The existence of a possible backflow in the lobe is considered to relate spectral with dynamical determinations of the age and the velocity with respect to the external medium. Through a very simple model, we obtain a physical characterization of the jets and the external medium in which the radio galaxy expands. The results in 8C 0821+695 are consistent with a relativistic jet nourishing the lobes which expand in a hot, low density halo. We infer a deceleration of the source expansion velocity which we explain through a progressive increase in the hot-spot size. C1 CSIC, Inst Astrofis Andalucia, Granada 18080, Spain. CNR, Ist Radioastron, I-40129 Bologna, Italy. Univ Bonn, Inst Radioastron, D-53121 Bonn, Germany. Univ Calif Lawrence Livermore Natl Lab, IGPP, Livermore, CA 94550 USA. Natl Radio Astron Observ, Charlottesville, VA 22903 USA. Sterrewacht Leiden, NL-2300 RA Leiden, Netherlands. Univ Bologna, Dipartimento Fis, I-40127 Bologna, Italy. Dipartimento Astron, I-40127 Bologna, Italy. RP Lara, L (reprint author), CSIC, Inst Astrofis Andalucia, Apdo 3004, Granada 18080, Spain. OI Feretti, Luigina/0000-0003-0312-6285 NR 36 TC 11 Z9 11 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 APR PY 2000 VL 356 IS 1 BP 63 EP 72 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 311DJ UT WOS:000086869300015 ER PT J AU De Breuck, C van Breugel, W Rottgering, HJA Miley, G AF De Breuck, C van Breugel, W Rottgering, HJA Miley, G TI A sample of 669 ultra steep spectrum radio sources to find high redshift radio galaxies SO ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES LA English DT Review DE surveys; galaxies : active; radio continuum : galaxies ID NRAO PMN SURVEYS; VLA-SKY-SURVEY; FLUX-DENSITY MEASUREMENTS; SOURCE CATALOG; OPTICAL IDENTIFICATIONS; STELLAR POPULATIONS; EVOLUTIONARY STATUS; CLUSTER GALAXIES; SPECTROSCOPY; MHZ AB Since radio sources with Ultra Steep Spectra (USS; alpha less than or similar to -1.30; S proportional to nu(alpha)) are efficient tracers of high redshift radio galaxies (HzRGs), we have defined three samples of such USS sources using the recently completed WENSS, TEXAS, MRC, NVSS and PMN radio-surveys. Our combined sample contains 669 sources with S(140)0 > 10 mJy and covers virtually the entire sky outside the Galactic plane (\b\ > 15 degrees). For our 2 largest, samples, covering delta > -35 degrees, we selected only sources with angular sizes Theta < 1', For 410 sources, we present radio-maps with 0." 3 to similar to 5 " resolution from VLA and ATCA observations or from the FIRST survey, which allows the optical identification of these radio sources. Comparison with spectrally unbiased samples at similar flux density levels, shows that our spectral index, flux density, and angular size selections do not affect the angular size distribution of the sample, but do avoid significant contributions by faint foreground spiral galaxies. We find that the spectral index distribution of 143000 sources from the WENSS and NVSS consists of a steep spectrum galaxy and a flat spectrum quasar population, with the relative contribution of flat spectrum sources doubling from S(1400) > 0.1 Jy to S(1400) > 2 5 Jy, The identification fraction of our USS sources on the POSS (R less than or similar to 20) is as low as 15%, independent of spectral index alpha < -1.30. We further show that 85% of the USS sources that can be identified with art X-ray source are probably contained in galaxy clusters, and that alpha < -1.6 sources are excellent Galactic pulsar candidates, because the percentage of these sources is four times higher in the Galactic piano. Our sample has been constructed to start an intensive campaign to obtain a large sample of high redshift objects (z > 3) that is selected in a way that does not suffer from dust extinction or any other optical bias(1). C1 Sterrewacht Leiden, NL-2300 RA Leiden, Netherlands. Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. RP De Breuck, C (reprint author), Sterrewacht Leiden, Postbus 9513, NL-2300 RA Leiden, Netherlands. EM debreuck@strw.leidenuniv.nl; wil@igpp.ucllnl.org; rottgeri@strw.leidenuniv.nl; miley@strw.leidenuniv.nl OI De Breuck, Carlos/0000-0002-6637-3315 NR 104 TC 125 Z9 129 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 0365-0138 J9 ASTRON ASTROPHYS SUP JI Astron. Astrophys. Suppl. Ser. PD APR PY 2000 VL 143 IS 2 BP 303 EP 333 PG 31 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 308EX UT WOS:000086698500009 ER PT J AU Remington, BA Drake, RP Arnett, D Takabe, H AF Remington, BA Drake, RP Arnett, D Takabe, H TI Proceedings of the Second International Workshop on Laboratory Astrophysics with Intense Lasers - Introduction SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Editorial Material C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Univ Arizona, Tucson, AZ 85721 USA. Osaka Univ, Suita, Osaka 565, Japan. RP Remington, BA (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RI Drake, R Paul/I-9218-2012 OI Drake, R Paul/0000-0002-5450-9844 NR 0 TC 4 Z9 4 U1 1 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2000 VL 127 IS 2 BP 211 EP 211 DI 10.1086/313369 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337FN UT WOS:000088346900001 ER PT J AU Back, CA Woolsey, NC Missalla, T Landen, OL Libby, SB Klein, LS Lee, RW AF Back, CA Woolsey, NC Missalla, T Landen, OL Libby, SB Klein, LS Lee, RW TI Implosions: An experimental testbed for high energy density physics SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT 2nd International Workshop on Laboratory Astrophysics with Intense Lasers CY MAR 19-21, 1998 CL TUCSON, ARIZONA DE methods : laboratory; plasmas; shock waves ID RADIATION HEAT WAVES; SOFT X-RAYS; LASER-LIGHT; PLASMAS; DRIVEN; TEMPERATURES; SPECTROSCOPY; COMPRESSION; CONVERSION AB The Nova laser facility has been used to produce matter in extreme conditions in the laboratory. The plasmas are produced by imploding spherical capsules filled with deuterium and trace amounts of Ar. A spectroscopic study of these indirectly driven, inertially confined plasmas provides measurements of the plasma parameters as a function of time. Multiple diagnostics measure peak n(e) similar to 1 x 10(24) cm(-3) and T-e similar to 1000 eV. A series of experiments have demonstrated that the results are reliable and reproducible. These experiments are designed to produce laboratory implosions that can serve as a "testbed" for high energy density matter. Measuring temperature gradients are the next step so that they can become sources suitable for studying physics such as high-density plasma effects or radiative cooling. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Queens Univ Belfast, Sch Math & Phys, Belfast BT7 1NN, Antrim, North Ireland. Howard Univ, Dept Phys, Washington, DC 20059 USA. RP Back, CA (reprint author), Univ Calif Lawrence Livermore Natl Lab, L-21,POB 808, Livermore, CA 94551 USA. NR 23 TC 4 Z9 4 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2000 VL 127 IS 2 BP 227 EP 232 DI 10.1086/313360 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337FN UT WOS:000088346900004 ER PT J AU Budil, KS Gold, DM Estabrook, KG Remington, BA Kane, J Bell, PM Pennington, DM Brown, C Hatchett, SP Koch, JA Key, MH Perry, MD AF Budil, KS Gold, DM Estabrook, KG Remington, BA Kane, J Bell, PM Pennington, DM Brown, C Hatchett, SP Koch, JA Key, MH Perry, MD TI Development of a radiative-hydrodynamics testbed using the Petawatt Laser facility SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT 2nd International Workshop on Laboratory Astrophysics with Intense Lasers CY MAR 19-21, 1998 CL TUCSON, ARIZONA DE gamma rays : bursts; hydrodynamics; methods : laboratory; shock waves; supernova remnants ID HOT-ELECTRONS; BLAST WAVES; SHOCKS AB Many of the conditions believed to underlie astrophysical phenomena have been difficult to achieve in a laboratory setting. For example, models of supernova remnant evolution rely on a detailed understanding of the propagation of shock waves with gigabar pressures at temperatures of 1 keV or more, at which radiative effects can be important. Current models of gamma-ray bursts posit a relativistically expanding plasma fireball with copious production of electron-positron pairs, a difficult scenario to verify experimentally. However, a new class of lasers, such as the Petawatt Laser, is capable of producing focused intensities greater than 10(20) W cm(-2), at which such relativistic effects can be observed and even dominate the laser-target interaction. We report here on the development of a testbed using the Petawatt Laser to study the evolution of strong, radiative shock waves. There is ample evidence in observational data from supernova remnants of the aftermath of the passage of radiative shock or blast waves. In the early phases of supernova remnant evolution, the radially expanding shock wave expands nearly adiabatically since it is traveling at a very high velocity as it begins to sweep up the surrounding interstellar gas. A Sedov-Taylor blast wave solution can be applied to this phase when the mass of interstellar gas swept up by the blast greatly exceeds the mass of the stellar ejecta, or a self-similar driven wave model can be applied if the ejecta play a significant role. As the mass of the swept-up material begins to greatly exceed the mass of the stellar ejecta, the evolution transitions to a radiative phase wherein the remnant can be modeled as an interior region of low-density, high-pressure gas surrounded by a thin, spherical shell of cooled, dense gas with a radiative shock as its outer boundary, the pressure-driven snowplow. Until recently it has not been feasible to devise laboratory experiments wherein shock waves with initial pressures in excess of several hundred megabars and temperatures approaching 1 keV are achieved in order to validate the models of the expanding blast wave launched by a supernova in both of its phases of evolution. This new experiment was designed to follow the propagation of a strong blast wave launched by the interaction of an intense short-pulse laser with a solid target. This blast wave is generated by the irradiation of the front surface of a layered, solid target with similar to 400 J of 1 mu m laser radiation in a 20 ps pulse focused to a similar to 50 mu m diameter spot, which produces an intensity in excess of 10(18) cm(-2). These conditions approximate a point explosion, and a blast wave that has an initial pressure of cm several hundred megabars and that decays as it travels approximately radially outward from the interaction region is predicted to be generated. We have utilized streaked optical pyrometry of the blast front to determine its time of arrival at the rear surface of the target. Applications of a self-similar Taylor-Sedov blast wave solution allows the amount of energy deposited to be estimated. By varying the parameters of the laser pulse that impinges on the target, pressures on the order of 1 Gbar with initial temperatures in excess of 1 keV are achievable. At these temperatures and densities radiative processes are coupled to the hydrodynamic evolution of the system. Short-pulse lasers produce a unique environment for the study of coupled radiation hydrodynamics in a laboratory setting. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Budil, KS (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94550 USA. NR 22 TC 7 Z9 7 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2000 VL 127 IS 2 BP 261 EP 265 DI 10.1086/313358 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337FN UT WOS:000088346900009 ER PT J AU Cauble, R Celliers, PM Collins, GW da Silva, LB Gold, DM Foord, ME Budil, KS Wallace, RJ Ng, A AF Cauble, R Celliers, PM Collins, GW da Silva, LB Gold, DM Foord, ME Budil, KS Wallace, RJ Ng, A TI Equation of state and material property measurements of hydrogen isotopes at the high-pressure, high-temperature, insulator-metal transition SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT 2nd International Workshop on Laboratory Astrophysics with Intense Lasers CY MAR 19-21, 1998 CL TUCSON, ARIZONA DE atomic processes; equation of state; methods : laboratory; shock waves ID COMPRESSED LIQUID DEUTERIUM; LOW-MASS STARS; HIGH-DENSITY; FLUID HYDROGEN; SHOCK-WAVES; MOLECULAR-HYDROGEN; GIANT PLANETS; BROWN DWARFS; DISSOCIATION; HUGONIOT AB A high-intensity laser was used to shock compress liquid deuterium to pressures between 0.22 and 3.4 megabars (Mbar). Shock density, pressure, and temperature were determined using a variety of experimental techniques and diagnostics. This pressure regime spans the transformation of deuterium from an insulating molecular fluid to an atomic metallic fluid. Data reveal a significant increase in compressibility and a temperature inflection near 1 Mbar, both indicative of such a transition. Single-wavelength reflectivity measurements of the shock front demonstrated that deuterium shocked above similar to 0.5 Mbar is indeed metallic. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ British Columbia, Vancouver, BC V5Z 1M9, Canada. RP Cauble, R (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94550 USA. NR 46 TC 22 Z9 22 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2000 VL 127 IS 2 BP 267 EP 273 DI 10.1086/313359 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337FN UT WOS:000088346900010 ER PT J AU Dappen, W Nayfonov, A AF Dappen, W Nayfonov, A TI The Sun as an equation-of-state laboratory SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT 2nd International Workshop on Laboratory Astrophysics with Intense Lasers CY MAR 19-21, 1998 CL TUCSON, AZ DE atomic processes; equation of state; Sun : interior; Sun : oscillations ID SOLAR 5-MINUTE OSCILLATION; LARKIN PARTITION-FUNCTION; DEPENDENT GROUND-STATE; VIRIAL EXPANSIONS; STELLAR ENVELOPES; QUANTUM PLASMAS; INTERIOR; HELIOSEISMOLOGY; OPACITIES; OPAL AB Thanks to helioseismology, the equation of state of the plasma of the solar interior can be diagnosed. Although the gas in the solar interior is only weakly coupled and weakly degenerate, the great observational accuracy of the helioseismic measurements puts strong constraints on the nonideal part of the equation of state. The helioseismic verification of major nonideal effects in the equation of state of solar matter has become well established. The dominant contribution is the Coulomb pressure, conventionally described in the Debye-Huckel approximation. However, recently the increased precision of the helioseismic diagnosis has brought significant observational progress beyond the Debye-Huckel approximation. This is illustrated with the subtle effect of excited states in bound systems, in particular hydrogen. C1 Univ So Calif, Dept Phys & Astron, Los Angeles, CA 90089 USA. Aarhus Univ, Inst Phys & Astron, Theoret Astrophys Ctr, Aarhus, Denmark. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. Lawrence Livermore Natl Lab, IGPP, Livermore, CA 94550 USA. RP Dappen, W (reprint author), Univ So Calif, Dept Phys & Astron, Los Angeles, CA 90089 USA. NR 62 TC 16 Z9 16 U1 0 U2 1 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 APR PY 2000 VL 127 IS 2 BP 287 EP 292 DI 10.1086/313356 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337FN UT WOS:000088346900013 ER PT J AU Ditmire, T Rubenchik, A Mirnov, VV Ucer, D AF Ditmire, T Rubenchik, A Mirnov, VV Ucer, D TI Modeling of the expansion of ultra-short-pulse laser-produced plasmas in magnetic fields SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT 2nd International Workshop on Laboratory Astrophysics with Intense Lasers CY MAR 19-21, 1998 CL TUCSON, ARIZONA DE magnetic fields; methods : analytical; methods : laboratory; plasmas AB The study of hot plasma expansion in a uniform magnetic field is of interest for many astrophysical applications. In order to observe this process in laboratory, an experiment is proposed in which an ultrashort laser pulse produces a high-temperature plasma by irradiation of a jet of atomic clusters. The very high laser light absorption exhibited in such a gas of clusters facilitates the creation of a hot (> 5 keV), dense (10(19)-10(20) cm(-3)) plasma with a sharp boundary. The small scale of the plasma (<100 mu m radius) permits the use of a strong magnetic field (> 1T). Pump-probe techniques can then be used to diagnose the density and magnetic field with high spatial and temporal resolution (<50fs). In the present work the expansion rate of the plasma and deceleration caused by the magnetic field are examined analytically. Electrodynamical aspects related to the radiation and transformation of energy are considered as well. The results obtained can be used in treating experimental data, studying magnetic R-T instabilities and other phenomena of astrophysical significance. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Middle E Tech Univ, Dept Phys, TR-06531 Ankara, Turkey. RP Ditmire, T (reprint author), Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 4 TC 11 Z9 11 U1 1 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2000 VL 127 IS 2 BP 293 EP 297 DI 10.1086/313332 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337FN UT WOS:000088346900014 ER PT J AU Ditmire, T Shigemori, K Remington, BA Estabrook, K Smith, RA AF Ditmire, T Shigemori, K Remington, BA Estabrook, K Smith, RA TI The production of strong blast waves through intense laser irradiation of atomic clusters SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT 2nd International Workshop on Laboratory Astrophysics with Intense Lasers CY MAR 19-21, 1998 CL TUCSON, ARIZONA DE atomic processes; hydrodynamics; plasmas; radiative transfer; shock waves ID X-RAY-EMISSION; PULSES; SHOCKS; TEMPERATURE; EXPLOSION; MODELS; GAS AB An understanding of radiation effects on the evolution of shock waves is of great importance to many problems in astrophysics. Shock waves driven by a laser-heated plasma are attractive for laboratory investigation of these phenomena. Recent studies of intense short-pulse laser interactions with gases of atomic clusters indicate a potential avenue to access this regime of radiative hydrodynamics. We have measured the energy absorption efficiency of high-intensity, picosecond laser pulses in low-density gases composed of large atomic clusters and find that the energy absorption can be very high (> 95%), producing a high-temperature plasma filament which consequently produces a strong blast wave. Interferometric characterization of these shock waves indicates that in high-Z gases such as Xe, radiation transport plays an important role in the evolution of the shock wave. C1 Univ Calif Lawrence Livermore Natl Lab, Laser Program, Livermore, CA 94550 USA. RP Ditmire, T (reprint author), Univ Calif Lawrence Livermore Natl Lab, Laser Program, L-477,7000 East Ave, Livermore, CA 94550 USA. RI Shigemori, Keisuke/B-3262-2013 OI Shigemori, Keisuke/0000-0002-3978-8427 NR 27 TC 40 Z9 40 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2000 VL 127 IS 2 BP 299 EP 304 DI 10.1086/313357 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337FN UT WOS:000088346900015 ER PT J AU Drake, RP Smith, TB Carroll, JJ Yan, Y Glendinning, SG Estabrook, K Ryutov, DD Remington, BA Wallace, RJ McCray, R AF Drake, RP Smith, TB Carroll, JJ Yan, Y Glendinning, SG Estabrook, K Ryutov, DD Remington, BA Wallace, RJ McCray, R TI Progress toward the laboratory simulation of young supernova remnants SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT 2nd International Workshop on Laboratory Astrophysics with Intense Lasers CY MAR 19-21, 1998 CL TUCSON, ARIZONA DE hydrodynamics; instabilities; supernova remnants; shock waves ID HYDRODYNAMIC INSTABILITY EXPERIMENTS; CASSIOPEIA-A; X-RAY; DRIVEN; NOVA; EMISSION; SHOCKS; 1987A; LASER AB Progress in experiments to simulate the hydrodynamics of supernova remnants (SNRs) in the laboratory is reported. The experiment design involves shock heating of a dense material, which expands to become the ejecta that drive a blast wave through low-density foam. In the design, a variety of issues, such as radiative preheat of the unshocked matter, had to be addressed. A careful analysis of the scaling between hydrodynamic systems shows that the experiment is a good, scaled model of a local region in a young SNR. Measurements of the basic hydrodynamic behavior for two blast-wave velocities are nearly complete. Measurements of hydrodynamic instabilities at the contact surface between the ejecta and the low-density matter will commence in the near future. C1 Univ Michigan, Ann Arbor, MI 48109 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Univ Colorado, JILA, Boulder, CO 80309 USA. RP Drake, RP (reprint author), Univ Michigan, 2455 Hayward St, Ann Arbor, MI 48109 USA. RI Drake, R Paul/I-9218-2012 OI Drake, R Paul/0000-0002-5450-9844 NR 22 TC 6 Z9 6 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2000 VL 127 IS 2 BP 305 EP 310 DI 10.1086/313348 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337FN UT WOS:000088346900016 ER PT J AU Farley, DR Logory, LM AF Farley, DR Logory, LM TI Single-mode, nonlinear mix experiments at high Mach number using Nova SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT 2nd International Workshop on Laboratory Astrophysics with Intense Lasers CY MAR 19-21, 1998 CL TUCSON, ARIZONA DE hydrodynamics; instabilities; methods : laboratory; shock waves; supernovae : general; turbulence ID RICHTMYER-MESHKOV INSTABILITY; RAYLEIGH-TAYLOR INSTABILITY; VARIABLE ACCELERATION; SIMULATION; FRONTS AB Nonlinear growth of an unstable density interface from single-mode initial perturbations at high Mach number was studied using the Nova laser. A variety of initially nonlinear perturbations were used, having amplitude-to-wavelength ratios of a(0)/lambda = 0.11, 0.22, and 0.43. The measured mix width data from these experiments were nondimensionalized and exhibit self-similar growth. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Farley, DR (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94551 USA. NR 24 TC 5 Z9 5 U1 1 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2000 VL 127 IS 2 BP 311 EP 316 DI 10.1086/313352 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337FN UT WOS:000088346900017 ER PT J AU Glendinning, SG Budil, KS Cherfils, C Drake, RP Farley, D Kalantar, DH Kane, J Marinak, MM Remington, BA Richard, A Ryutov, D Stone, J Wallace, RJ Weber, SV AF Glendinning, SG Budil, KS Cherfils, C Drake, RP Farley, D Kalantar, DH Kane, J Marinak, MM Remington, BA Richard, A Ryutov, D Stone, J Wallace, RJ Weber, SV TI Experimental measurements of hydrodynamic instabilities on Nova of relevance to astrophysics SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT 2nd International Workshop on Laboratory Astrophysics with Intense Lasers CY MAR 19-21, 1998 CL TUCSON, ARIZONA DE hydrodynamics; instabilities; methods : laboratory ID RAYLEIGH-TAYLOR INSTABILITY; LASER; GROWTH; PHOTOEVAPORATION; IMPLOSIONS; CAMERAS AB Large lasers such as Nova allow the possibility of achieving regimes of high-energy densities in plasmas of millimeter spatial scales and nanosecond timescales. In those plasmas where thermal conductivity and viscosity do not play a significant role, the hydrodynamic evolution is suitable for benchmarking hydrodynamics modeling in astrophysical codes. Several experiments on Nova examine hydrodynamically unstable interfaces. A typical Nova experiment uses a gold millimeter-scale hohlraum to convert the laser energy to a 200 eV blackbody source lasting about a nanosecond. The X-rays ablate a planar target, generating a series of shocks and accelerating the target. The evolving areal density is diagnosed by time-resolved radiography, using a second X-ray source. Data from several experiments are presented and diagnostic techniques are discussed. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. CEA, F-91680 Bruyeres Le Chatel, France. Univ Michigan, Ann Arbor, MI 48109 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RP Glendinning, SG (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94551 USA. RI Drake, R Paul/I-9218-2012 OI Drake, R Paul/0000-0002-5450-9844 NR 24 TC 1 Z9 1 U1 0 U2 6 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2000 VL 127 IS 2 BP 325 EP 331 DI 10.1086/313344 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337FN UT WOS:000088346900020 ER PT J AU Gold, DM Celliers, PM Collins, GW Budil, KS Cauble, R da Silva, LB Foord, ME Stewart, RE Wallace, RJ Young, D AF Gold, DM Celliers, PM Collins, GW Budil, KS Cauble, R da Silva, LB Foord, ME Stewart, RE Wallace, RJ Young, D TI Interferometric and chirped optical probe techniques for high-pressure equation-of-state measurements SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT 2nd International Workshop on Laboratory Astrophysics with Intense Lasers CY MAR 19-21, 1998 CL TUCSON, ARIZONA DE equation of state; methods : laboratory; plasmas; shock waves; techniques : interferometric ID DEUTERIUM; PLASMAS AB We present experimental work exploring displacement and velocity interferometry as high spatial and temporal resolution diagnostics for measuring target preheat and the speed, planarity, and steadiness of a shock wave. A chirped pulse reflectometry experiment is also proposed as a frequency domain alternative for shock speed measurements. These techniques fill a need for high-precision diagnostics to derive accurate laboratory-based equation-of-state data at shock wave-driven pressures directly relevant to astrophysical systems. The performance of these optical laser probe techniques may exceed conventional passive techniques such as temporally streaked recording of optical emission upon shock breakout or side-on streaked X-ray radiography. Results from Nova laser and high-intensity ultrashort pulse experiments are presented. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Gold, DM (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 10 TC 4 Z9 4 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2000 VL 127 IS 2 BP 333 EP 337 DI 10.1086/313345 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337FN UT WOS:000088346900021 ER PT J AU Hartemann, FV Troha, AL Baldis, HA Gupta, A Kerman, AK Landahl, EC Luhmann, NC Van Meter, JR AF Hartemann, FV Troha, AL Baldis, HA Gupta, A Kerman, AK Landahl, EC Luhmann, NC Van Meter, JR TI High-intensity scattering processes of relativistic electrons in vacuum and their relevance to high-energy astrophysics SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT 2nd International Workshop on Laboratory Astrophysics with Intense Lasers CY MAR 19-21, 1998 CL TUCSON, AZ DE acceleration of particles; gamma rays; methods : laboratory; plasmas; radiation mechanisms : nonthermal; scattering ID ABOVE-THRESHOLD IONIZATION; LASER-PULSES; ELECTROMAGNETIC-WAVES; COMPTON-SCATTERING; NOVA LASER; PLASMA; ACCELERATION; RADIATION; COLLISIONS; INSTABILITY AB The recent advent of ultra-short pulse, high-intensity lasers, together with advances in other novel technologies, such as high-gradient radiofrequency photoinjectors, have afforded researchers the possibility to simulate astrophysical conditions in the laboratory. Laser-produced plasmas have been successfully used to simulate astrophysical plasmas and supernovae in the laboratory for several years. Now, femtosecond laser systems operating in the terawatt to petawatt range are available, as are synchronized relativistic electron bunches with subpicosecond durations and terahertz bandwidths. With these tools, experiments have been conducted to study phenomena related to supernova explosions, stellar winds, solar coronae, cosmic rays, planetary and celestial matter, and interstellar plasmas. Other experiments have been proposed to investigate Unruh radiation, as well as ponderomotive scattering, which can accelerate electrons in vacuum to relativistic energies using the extremely high gradients in a three-dimensional laser focus. The nonlinear Doppler shift induced by ultrarelativistic radiation pressure is shown to yield complex nonlinear Compton backscattered spectra. Finally, strong radiative corrections are expected when the Doppler-upshifted laser wavelength approaches the Compton scale. These are discussed within the context of high-held classical electrodynamics, a new discipline borne out of the aforementioned innovations. C1 Lawrence Livermore Natl Lab, Inst Laser Sci & Applicat, Livermore, CA 94550 USA. Univ Calif Davis, Dept Appl Sci, Davis, CA 95616 USA. CUNY City Coll, Dept Elect Engn, New York, NY 10031 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. MIT, Ctr Theoret Phys, Cambridge, MA 02139 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. RP Lawrence Livermore Natl Lab, Inst Laser Sci & Applicat, POB 808, Livermore, CA 94550 USA. RI Landahl, Eric/A-1742-2010; van meter, james/E-7893-2011 NR 64 TC 7 Z9 7 U1 0 U2 6 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 EI 1538-4365 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2000 VL 127 IS 2 BP 347 EP 356 DI 10.1086/313347 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337FN UT WOS:000088346900023 ER PT J AU Kalantar, DH Remington, BA Chandler, EA Colvin, JD Gold, DM Mikaelian, KO Weber, SV Wiley, LG Wark, JS Loveridge, A Hauer, A Failor, BH Meyers, MA Ravichandran, G AF Kalantar, DH Remington, BA Chandler, EA Colvin, JD Gold, DM Mikaelian, KO Weber, SV Wiley, LG Wark, JS Loveridge, A Hauer, A Failor, BH Meyers, MA Ravichandran, G TI Developing solid-state experiments on the Nova laser SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT 2nd International Workshop on Laboratory Astrophysics with Intense Lasers CY MAR 19-21, 1998 CL TUCSON, ARIZONA DE instabilities; methods : laboratory; shock waves; X-rays : general AB An X-ray drive has been developed to shock compress metal foils in the solid state using an internally shielded hohlraum with a high contrast shaped pulse from the Nova laser. The drive has been characterized, and hydrodynamics experiments designed to study the growth of the Rayleigh-Taylor (R-T) instability in Cu foils at 3 Mbar peak pressures in the plastic how regime have been started. Preimposed 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 the Nova experiments, 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 of the R-T growth are significantly enhanced. The conditions reached in the metal foils at peak compression are similar to those predicted at the core of Earth. 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. Phys Int Co, San Leandro, CA 94577 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. CALTECH, Pasadena, CA 91125 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 15 TC 3 Z9 3 U1 0 U2 6 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2000 VL 127 IS 2 BP 357 EP 363 DI 10.1086/313324 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337FN UT WOS:000088346900024 ER PT J AU Kane, J Arnett, D Remington, BA Glendinning, SG Bazan, G Drake, RP Fryxell, BA AF Kane, J Arnett, D Remington, BA Glendinning, SG Bazan, G Drake, RP Fryxell, BA TI Supernova experiments on the Nova laser SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT 2nd International Workshop on Laboratory Astrophysics with Intense Lasers CY MAR 19-21, 1998 CL TUCSON, ARIZONA DE hydrodynamics; instabilities; ISM : bubbles; methods : laboratory; shock waves; supernovae : individual (SN 1987A) ID RAYLEIGH-TAYLOR INSTABILITY; LINE-PROFILES; SN-1987A; 1987A; PERTURBATIONS; HYDRODYNAMICS; SIMILARITY; SIMULATION; EVOLUTION; FRONTS AB Supernova (SN) 1987A focused attention on the critical role of hydrodynamic instabilities in the evolution of supernovae. To test the modeling of these instabilities, we are developing laboratory experiments of hydrodynamic mixing under conditions relevant to supernovae. Initial results were reported by Kane et al. in a recent paper. The Nova laser is used to generate a 10-15 Mbar shock at the interface of a two-layer planar target, which triggers perturbation growth, due to the Richtmeyer-Meshkov instability, and to the Rayleigh-Taylor instability as the interface decelerates. This resembles the hydrodynamics of the He-H interface of a Type II supernova at intermediate times, up to a few times 10(3) s. The experiment is modeled using the hydrodynamics codes HYADES and GALE, and the supernova code PROMETHEUS. Results of the experiments and simulations are presented. We also present new analysis of the bubble velocity, a study of two-dimensional versus three-dimensional difference in growth at the He-H interface of SN 1987A, and designs for two-dimensional versus three-dimensional hydro experiments. C1 Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Michigan, Ann Arbor, MI 48109 USA. NASA, GFC, Greenbelt, MD 20771 USA. RP Kane, J (reprint author), Univ Arizona, Steward Observ, Mail Code L-411 LLNL, Tucson, AZ 85721 USA. RI Drake, R Paul/I-9218-2012 OI Drake, R Paul/0000-0002-5450-9844 NR 30 TC 11 Z9 11 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2000 VL 127 IS 2 BP 365 EP 369 DI 10.1086/313349 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337FN UT WOS:000088346900025 ER PT J AU Keilty, K Liang, E Remington, B London, R Estabrook, K Kane, J AF Keilty, K Liang, E Remington, B London, R Estabrook, K Kane, J TI Numerical simulations of blast waves generated by an impulsive temperature source SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT 2nd International Workshop on Laboratory Astrophysics with Intense Lasers CY MAR 19-21, 1998 CL TUCSON, ARIZONA DE methods : numerical; shock waves; supernovae : general AB We describe some of the results arriving from numerical simulations of blast waves using different volumes for the energy deposition region. C1 Rice Univ, Dept Space Phys & Astron, Houston, TX 77005 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Keilty, K (reprint author), Rice Univ, Dept Space Phys & Astron, Mail Stop 108,6100 Main St, Houston, TX 77005 USA. NR 3 TC 5 Z9 5 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2000 VL 127 IS 2 BP 375 EP 377 DI 10.1086/313351 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337FN UT WOS:000088346900027 ER PT J AU Klein, RI Budil, KS Perry, TS Bach, DR AF Klein, RI Budil, KS Perry, TS Bach, DR TI Interaction of supernova remnants with interstellar clouds: From the nova laser to the galaxy SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT 2nd International Workshop on Laboratory Astrophysics with Intense Lasers CY MAR 19-21, 1998 CL TUCSON, ARIZONA DE hydrodynamics; ISM : general; shock waves; supernova remnants ID GAS CLOUDS; IMPLOSION AB The interaction of strong shock waves, such as those generated by the explosion of supernovae with interstellar clouds, is a problem of fundamental importance in understanding the evolution and the dynamics of the interstellar medium (ISM) as it is disrupted by shock waves. The physics of this essential interaction sheds light on several key questions: (1) What is the rate and total amount of gas stripped from the cloud, and what are the mechanisms responsible? (2) What is the rate of momentum transfer to the cloud? (3) What is the appearance of the shocked cloud, its morphology and velocity dispersion? (4) What is the role of vortex dynamics on the evolution of the cloud? (5) Can the interaction result in the formation of a new generation of stars? To address these questions, one of us has embarked on a comprehensive multidimensional numerical study of the shock cloud problem using high-resolution adaptive mesh refinement (AMR) hydrodynamics. Here we present the results of a series of Nova laser experiments investigating the evolution of a high-density sphere embedded in a low-density medium after the passage of a strong shock, wave, thereby emulating the supernova shock-cloud interaction. The Nova laser was utilized to generate a strong (similar to Mach 10) shock wave which traveled along a miniature beryllium shock tube, 750 mu m in diameter, filled with a low-density plastic emulating the ISM. Embedded in the plastic was a copper microsphere (100 mu m in diameter) emulating the interstellar cloud. Its morphology and evolution as well as the shock wave trajectory were diagnosed via side-on radiography. We describe here experimental results of this interaction for the first time out to several cloud crushing times and compare them to detailed two- and three-dimensional radiation hydrodynamic simulations using both arbitrary Lagrangian and Eulerian hydrodynamics (ALE) as well as high-resolution AMR hydrodynamics. We briefly discuss the key hydrodynamic instabilities instrumental in destroying the cloud and show the importance of inherently three-dimensional instabilities and their role in cloud evolution. We describe the relationship of these new experiments and calculations to recent ROSAT X-ray observations in the Cygnus Loop. C1 Univ Calif Berkeley, Dept Astron, Berkeley, CA 94270 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Klein, RI (reprint author), Univ Calif Berkeley, Dept Astron, 601 Campbell Hall, Berkeley, CA 94270 USA. RI Perry, Theodore/K-3333-2014 OI Perry, Theodore/0000-0002-8832-2033 NR 10 TC 22 Z9 22 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2000 VL 127 IS 2 BP 379 EP 383 DI 10.1086/313342 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337FN UT WOS:000088346900028 ER PT J AU Logory, LM Miller, PL Stry, PE AF Logory, LM Miller, PL Stry, PE TI Nova high-speed jet experiments SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT 2nd International Workshop on Laboratory Astrophysics with Intense Lasers CY MAR 19-21, 1998 CL TUCSON, ARIZONA DE ISM : jets and outflows; methods : laboratory; shock waves; X-rays : general AB We have conducted high-speed jet experiments using the Nova laser facility located at the Lawrence Livermore National Laboratory. The experiments make use of energy deposited in a Nova hohlraum to launch a strong shock down the axis of a cylindrical, millimeter-scale package containing a plastic/foam interface. The passage of the shock, causes a hemispherical indentation at the interface to invert and form a plasma jet. The jet-tip velocity is approximately 60 km s(-1), with a corresponding jet-tip Mach number of about 17. An X-ray backlighter foil and an electronic X-ray framing camera are used to radiograph the flow side-on. Vortical structures are observed, and the development of the jet over time is measured. An additional set of experiments was undertaken to elucidate these structures using a tracer material. Numerical simulations have been performed to provide additional insights into this flow and to permit examination of unmeasured quantities. The experiments include aspects of observed astrophysical jet phenomena, which could prove useful for benchmarking codes. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Logory, LM (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94551 USA. RI Miller, Paul/E-6880-2013 NR 0 TC 17 Z9 18 U1 0 U2 5 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2000 VL 127 IS 2 BP 423 EP 428 DI 10.1086/313327 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337FN UT WOS:000088346900034 ER PT J AU Perry, TS Davidson, SJ Serduke, FJD Bach, DR Smith, CC Foster, JM Doyas, RJ Ward, RA Iglesias, CA Rogers, FJ Abdallah, J Stewart, RE Wallace, RJ Kilkenny, JD Lee, RW AF Perry, TS Davidson, SJ Serduke, FJD Bach, DR Smith, CC Foster, JM Doyas, RJ Ward, RA Iglesias, CA Rogers, FJ Abdallah, J Stewart, RE Wallace, RJ Kilkenny, JD Lee, RW TI Opacity measurements in a hot dense medium SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT 2nd International Workshop on Laboratory Astrophysics with Intense Lasers CY MAR 19-21, 1998 CL TUCSON, ARIZONA DE atomic data; methods : laboratory; plasmas; X-rays : general ID LASER-PRODUCED PLASMA; FLUORESCENCE; LINES AB Measurements of the opacity of aluminum in a well characterized, hot, dense, laser produced plasma are reported. Measurements of the absorption of X-rays by 1 to 2 transitions in Al XII through Al VIII have been made in a laser-heated slab plasma at the measured temperature and density of 58 +/- 4 eV and 0.020 +/- 0.007 g cm(-3). Separate measurements of the temperature and density were made. The conditions in the plasma were determined to be reproducible, spatially uniform, and in nearly complete local thermodynamic equilibrium. The absorption spectra and the temperature-density data obtained provide an improved means for comparison with detailed atomic physics and opacity calculations. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Atom Weapons Estab, Reading RG7 4PR, Berks, England. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Perry, TS (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94551 USA. RI Perry, Theodore/K-3333-2014 OI Perry, Theodore/0000-0002-8832-2033 NR 21 TC 5 Z9 5 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2000 VL 127 IS 2 BP 433 EP 436 DI 10.1086/313368 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337FN UT WOS:000088346900036 ER PT J AU Perry, TS Klein, RI Bach, DR Budil, KS Cauble, R Kornblum, HN Wallace, RJ Lee, RW AF Perry, TS Klein, RI Bach, DR Budil, KS Cauble, R Kornblum, HN Wallace, RJ Lee, RW TI Temperature and density measurements of the collision of two plasmas SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT 2nd International Workshop on Laboratory Astrophysics with Intense Lasers CY MAR 19-21, 1998 CL TUCSON, ARIZONA DE hydrodynamics; methods : laboratory; plasmas; shock waves; stars : formation; X-rays : general ID LASER; INTERPENETRATION AB An important example of interstellar shock-cloud interactions occurs when the shocks are generated by the collision of two interstellar clouds. It has been suggested that the cloud-cloud interaction may result in new star formation with some recent examples found in W49N leading to enhanced O star formation. In an attempt to study aspects of the collision in the laboratory, we have initiated a series of experiments designed to investigate the hydrodynamic motion of high-temperature plasmas produced by volumetric heating of thin aluminum foils. The foils were heated by gold M-band X-rays (2-4 keV) produced by laser radiation from the Nova laser impinging on 1500 Angstrom thick Au foils. In this way we were able to avoid nonuniformities which would exist with lower energy heating radiation. We studied single and double foils, and were able to measure the temperature and density of the plasma with accuracies sufficient for comparisons with radiation hydrodynamic simulations. The densities of the aluminum plasmas produced were inferred by measuring the transmission of the plasma to radiation produced by a tantalum backlighter. Time and spatial information were obtained using a gated X-ray framing camera. For the temperature measurements, we used a samarium backlight and X-ray absorption spectra were taken using a crystal spectrometer and photographic him. The backlight produced a 200 ps wide spectral snapshot. The temperature of each plasma was obtained by determining the ion balance in the plasma from the absorption spectrum of the aluminum 1-2 lines through the plasma. The temperature was extracted from the best ht in a series of transmission calculations at the measured density. The densities and temperatures the plasmas produced in these experiments were determined to be in the range 0.005-0.05 g cm(-3) and 20-40 eV. The temperature and density measurements were sufficiently accurate to make detailed comparisons to radiation hydrodynamic simulations and demonstrated some limitations of the simulations. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Perry, TS (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94550 USA. RI Perry, Theodore/K-3333-2014 OI Perry, Theodore/0000-0002-8832-2033 NR 9 TC 5 Z9 5 U1 1 U2 7 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2000 VL 127 IS 2 BP 437 EP 443 DI 10.1086/313333 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337FN UT WOS:000088346900037 ER PT J AU Rozmus, W Glenzer, SH Estabrook, KG Baldis, HA MacGowan, BJ AF Rozmus, W Glenzer, SH Estabrook, KG Baldis, HA MacGowan, BJ TI Modeling of Thomson scattering spectra in high-Z, laser-produced plasmas SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT 2nd International Workshop on Laboratory Astrophysics with Intense Lasers CY MAR 19-21, 1998 CL TUCSON, ARIZONA DE atomic processes; plasmas ID ELECTRON AB Theoretical calculations of a Thomson scattering cross section and dynamical form factors are presented for high-Z, laser-produced, inhomogeneous plasmas. Relevance of these results to astrophysical plasmas is pointed out. Comparisons with recent experimental observations are discussed with emphasis on the effects of plasma inhomogeneity, ion-ion collisions, and non-Maxwellian distribution functions. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Rozmus, W (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 19 TC 11 Z9 11 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2000 VL 127 IS 2 BP 459 EP 463 DI 10.1086/313319 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337FN UT WOS:000088346900040 ER PT J AU Ryutov, DD Drake, RP Remington, BA AF Ryutov, DD Drake, RP Remington, BA TI Criteria for scaled laboratory simulations of astrophysical MHD phenomena SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT 2nd International Workshop on Laboratory Astrophysics with Intense Lasers CY MAR 19-21, 1998 CL TUCSON, AZ DE hydrodynamics; methods : laboratory; MHD; shock waves ID INERTIAL CONFINEMENT FUSION; SUPERNOVA 1987A; NOVA LASER; HYDRODYNAMICS; INSTABILITY; RELEVANT; PHYSICS AB We demonstrate that two systems described by the equations of the ideal magnetohydrodynamics (MHD) evolve similarly, if the initial conditions are geometrically similar and certain scaling relations hold. The thermodynamic properties of the gas must be such that the internal energy density is proportional to the pressure. The presence of the shocks is allowed. We discuss the applicability conditions of the ideal MHD and demonstrate that they are satisfied with a large margin both in a number of astrophysical objects, and in properly designed simulation experiments with high-power lasers. This allows one to perform laboratory experiments whose results can be used for quantitative interpretation of various effects of astrophysical MHD. C1 Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Ryutov, DD (reprint author), Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RI Drake, R Paul/I-9218-2012 OI Drake, R Paul/0000-0002-5450-9844 NR 20 TC 89 Z9 93 U1 4 U2 21 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 EI 1538-4365 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2000 VL 127 IS 2 BP 465 EP 468 DI 10.1086/313320 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337FN UT WOS:000088346900041 ER PT J AU Starrfield, S Sparks, WM Truran, JW Wiescher, MC AF Starrfield, S Sparks, WM Truran, JW Wiescher, MC TI The effects of new nuclear reaction rates and opacities on hydrodynamic simulations of the nova outburst SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT 2nd International Workshop on Laboratory Astrophysics with Intense Lasers CY MAR 19-21, 1998 CL TUCSON, ARIZONA DE hydrodynamics; novae, cataclysmic variables; nuclear reactions, nucleosynthesis, abundances; white dwarf ID WHITE-DWARFS; SPECTRAL EVOLUTION; V1974 CYGNI; RP-PROCESS; MASS; SEQUENCES; MIXTURES; TABLES; MODELS AB We report on the results of new calculations of thermonuclear runaways on 1.25 M. oxygen, neon, and magnesium white dwarfs, using our one-dimensional, fully implicit, hydrodynamic stellar evolution code that includes a large nuclear reaction network. We have updated the nuclear reaction network by including both new and improved experimental and theoretical determinations of the nuclear reaction rates. We have also incorporated the carbon-rich OPAL opacity tables. Our results show that the changes in the reaction rates and opacities that we have introduced produce important changes with respect to our previous studies. For example, a smaller amount of Al-26 is produced, while the abundances of P-31 and S-32 increase by factors of more than 2. This change is attributed to the increased proton-capture reaction rates for some of the intermediate-mass nuclei near Al-26 and beyond, such that nuclear fusion to higher mass nuclei is enhanced. We also find that our predicted values for the amount of mass ejected in the outburst are at least a factor of 10 less than observed. The low values for the amount of ejected mass is a consequence of the fact that the OPAL opacities are larger than those we previously used, which results in more heat being trapped in the nuclear-burning regions and, therefore, less mass being accreted onto the white dwarf. C1 Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA. Univ Calif Los Alamos Natl Lab, XNH, Los Alamos, NM 87544 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. RP Starrfield, S (reprint author), Arizona State Univ, Dept Phys & Astron, POB 871504, Tempe, AZ 85287 USA. NR 38 TC 55 Z9 55 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2000 VL 127 IS 2 BP 485 EP 495 DI 10.1086/313336 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337FN UT WOS:000088346900045 ER PT J AU Stone, JM Turner, N Estabrook, K Remington, B Farley, D Glendinning, SG Glenzer, S AF Stone, JM Turner, N Estabrook, K Remington, B Farley, D Glendinning, SG Glenzer, S TI Testing astrophysical radiation hydrodynamics codes with hypervelocity jet experiments on the nova laser SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT 2nd International Workshop on Laboratory Astrophysics with Intense Lasers CY MAR 19-21, 1998 CL TUCSON, ARIZONA DE ISM : jets and outflows; methods : laboratory; shock waves ID NUMERICAL SIMULATIONS; PROTOSTELLAR JETS; INSTABILITY AB Recent shock-tube experiments using the Nova laser facility have demonstrated that strong shocks and highly supersonic flows similar to those encountered in astrophysical jets can be studied in detail through carefully controlled experiments. We propose the use of high-power lasers such as Nova, Omega, Gekko, and the National Ignition Facility (NIF) to perform experiments on radiation hydrodynamic problems such as jets involving the multidimensional dynamics of strong shocks. High-power lasers are the only experimental facilities that can reach the very high Mach number regime. The experiments will serve as diagnostics of astrophysically interesting gasdynamic problems and could also form the basis of test problems for numerical algorithms for astrophysical radiation hydrodynamic codes. The potential for experimentally achieving a strongly radiative jet seems very good. C1 Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Stone, JM (reprint author), Univ Maryland, Dept Astron, College Pk, MD 20742 USA. OI Turner, Neal/0000-0001-8292-1943 NR 25 TC 21 Z9 21 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2000 VL 127 IS 2 BP 497 EP 502 DI 10.1086/313337 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337FN UT WOS:000088346900046 ER PT J AU Teyssier, R Ryutov, D Remington, B AF Teyssier, R Ryutov, D Remington, B TI Accelerating shock waves in a laser-produced density gradient SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT 2nd International Workshop on Laboratory Astrophysics with Intense Lasers CY MAR 19-21, 1998 CL TUCSON, ARIZONA DE methods : numerical; shock waves; stars : atmospheres; supernova remnants; supernovae : general ID X-RAY; INSTABILITY; SUPERNOVAE AB We study the possibility of creating decreasing density gradients under laboratory conditions using high-energy lasers. The idea is to study the propagation of shock waves in such laser-produced "atmospheres" in order to test theories on shock acceleration and shock front stability. We investigate theoretically two experimental designs that could address this question. We consider first the case of a discrete, two density step package, showing that this experiment can result in very strong shock acceleration (a factor of 4). We finally consider the case of a continuously decreasing density package, obtained by indirect illumination of a plastic target by a thin gold foil. We obtained a 20 mu m thick exponential atmosphere, which is a perfect laboratory in which to study the stability of accelerating shock waves in a decreasing density gradient. C1 Ctr Etud Saclay, Dept Astrophys Phys Nucl & Instrumentat Associee, Serv Astrophys, Direct Sci Matiere,Commissariat Energie Atom, F-91191 Gif Sur Yvette, France. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Teyssier, R (reprint author), Ctr Etud Saclay, Dept Astrophys Phys Nucl & Instrumentat Associee, Serv Astrophys, Direct Sci Matiere,Commissariat Energie Atom, F-91191 Gif Sur Yvette, France. NR 8 TC 11 Z9 11 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2000 VL 127 IS 2 BP 503 EP 508 DI 10.1086/313338 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337FN UT WOS:000088346900047 ER PT J AU Rose, PP Korber, BT AF Rose, PP Korber, BT TI Detecting hypermutations in viral sequences with an emphasis on G -> A hypermutation SO BIOINFORMATICS LA English DT Article ID HUMAN-IMMUNODEFICIENCY-VIRUS; HEPATITIS-B VIRUS; G->A HYPERMUTATION; IN-VIVO; GENOMES AB This program compares sequence sets to a reference sequence, tallies G --> A hypermutations, and presents the results in various tables and graphs, which include dinucleotide context, summaries of all observed nucleotide changes, and stop codons introduced by hypermutation. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87544 USA. RP Rose, PP (reprint author), Univ Calif Los Alamos Natl Lab, MS K710, Los Alamos, NM 87544 USA. OI Korber, Bette/0000-0002-2026-5757 NR 10 TC 151 Z9 153 U1 0 U2 1 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 1367-4803 J9 BIOINFORMATICS JI Bioinformatics PD APR PY 2000 VL 16 IS 4 BP 400 EP 401 DI 10.1093/bioinformatics/16.4.400 PG 2 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 329XN UT WOS:000087933900012 PM 10869039 ER PT J AU Baumann, CG Bloomfield, VA Smith, SB Bustamante, C Wang, MD Block, SM AF Baumann, CG Bloomfield, VA Smith, SB Bustamante, C Wang, MD Block, SM TI Stretching of single collapsed DNA molecules SO BIOPHYSICAL JOURNAL LA English DT Article ID MULTIVALENT CATIONS; EQUILIBRIUM DIALYSIS; TRIVALENT CATIONS; LIGHT-SCATTERING; B-DNA; CONDENSATION; ELASTICITY; COUNTERIONS; COBALT(III); AGGREGATION AB The elastic response of single plasmid and lambda phage DNA molecules was probed using optical tweezers at concentrations of trivalent cations that provoked DNA condensation in bulk. For uncondensed plasmids, the persistence length, P, decreased with increasing spermidine concentration before reaching a limiting value 40 nm. When condensed plasmids were stretched, two types of behavior were observed: a stick-release pattern and a plateau at similar to 20 pN. These behaviors are attributed to unpacking from a condensed structure, such as coiled DNA. Similarly, condensing concentrations of hexaammine cobalt(III) (CoHex) and spermidine induced extensive changes in the tow and high force elasticity of lambda DNA. The high force (5-15 pN) entropic elasticity showed worm-like chain (WLC) behavior, with P two- to fivefold lower than in low monovalent salt. At lower forces, a 14-pN plateau abruptly appeared. This corresponds to an intramolecular attraction of 0.083-0.33 kT/bp, consistent with osmotic stress measurements in bulk condensed DNA. The intramolecular attractive force with CoHex is larger than with spermidine, consistent with the greater efficiency with which CoHex condenses DNA in bulk. The transition from WLC behavior to condensation occurs at an extension about 85% of the contour length, permitting looping and nucleation of condensation. Approximately half as many base pairs are required to nucleate collapse in a stretched chain when CoHex is the condensing agent. C1 Univ Minnesota, Dept Biochem, St Paul, MN 55108 USA. Univ Calif Berkeley, Dept Mol & Cell Biol, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA. Princeton Univ, Dept Mol Biol, Princeton, NJ 08544 USA. RP Bloomfield, VA (reprint author), Univ Minnesota, Dept Biochem, 1479 Gortner Ave, St Paul, MN 55108 USA. FU NIGMS NIH HHS [GM 08277, GM 28093, GM 32543] NR 50 TC 184 Z9 190 U1 2 U2 37 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD APR PY 2000 VL 78 IS 4 BP 1965 EP 1978 PG 14 WC Biophysics SC Biophysics GA 302DE UT WOS:000086349500028 PM 10733975 ER PT J AU Huston, M Scurlock, J Huston, A AF Huston, M Scurlock, J Huston, A TI Shifting the carbon balance SO BIOSCIENCE LA English DT Letter C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Robertsville Middle Sch, Oak Ridge, TN 37830 USA. RP Huston, M (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. RI Huston, Michael/B-1434-2009 OI Huston, Michael/0000-0001-9513-1166 NR 1 TC 1 Z9 1 U1 1 U2 2 PU AMER INST BIOLOGICAL SCI PI WASHINGTON PA 1444 EYE ST, NW, STE 200, WASHINGTON, DC 20005 USA SN 0006-3568 J9 BIOSCIENCE JI Bioscience PD APR PY 2000 VL 50 IS 4 BP 292 EP 292 DI 10.1641/0006-3568(2000)050[0292:STCB]2.3.CO;2 PG 1 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 300EL UT WOS:000086239800002 ER PT J AU Lai, CT Katul, G Ellsworth, D Oren, R AF Lai, CT Katul, G Ellsworth, D Oren, R TI Modelling vegetation-atmosphere CO2 exchange by a coupled Eulerian-Langrangian approach SO BOUNDARY-LAYER METEOROLOGY LA English DT Article DE canopy turbulence; Lagrangian stochastic model; turbulence closure; canopy photosynthesis; carbon dioxide; radiation attenuation ID TURBULENCE CLOSURE SCHEME; CONVECTIVE BOUNDARY-LAYER; CARBON-DIOXIDE EXCHANGE; RANDOM-WALK MODEL; PLANT CANOPIES; WATER-VAPOR; PINE FOREST; SOURCE DISTRIBUTIONS; STOCHASTIC-MODELS; PHOTOSYNTHESIS AB A Eulerian-Lagrangian canopy microclimate model was developed with the aim of discerning physical from biophysical controls of CO2 and H2O fluxes. The model couples radiation attenuation with mass, energy, and momentum exchange at different canopy levels. A unique feature of the model is its ability to combine higher order Eulerian closure approaches that compute velocity statistics with Lagrangian scalar dispersion approaches within the canopy volume. Explicit accounting for within-canopy CO2, H2O, and heat storage is resolved by considering non-steadiness in mean scalar concentration and temperature. A seven-day experiment was conducted in August 1998 to investigate whether the proposed model can reproduce temporal evolution of scalar (CO2, H2O and heat) fluxes, sources and sinks, and concentration profiles within and above a uniform 15-year old pine forest. The model reproduced well the measured depth-averaged canopy surface temperature, CO2 and H2O concentration profiles within the canopy volume, CO2 storage flux, net radiation above the canopy, and heat and mass fluxes above the canopy, as well as the velocity statistics near the canopy-atmosphere interface. Implications for scaling measured leaf-level biophysical functions to ecosystem scale are also discussed. C1 Duke Univ, Sch Environm, Durham, NC 27708 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Lai, CT (reprint author), Duke Univ, Sch Environm, Box 90328, Durham, NC 27708 USA. RI Katul, Gabriel/A-7210-2008; OI Katul, Gabriel/0000-0001-9768-3693; Ellsworth, David/0000-0002-9699-2272 NR 63 TC 51 Z9 53 U1 1 U2 7 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0006-8314 J9 BOUND-LAY METEOROL JI Bound.-Layer Meteor. PD APR PY 2000 VL 95 IS 1 BP 91 EP 122 DI 10.1023/A:1002473906184 PG 32 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 312NP UT WOS:000086949600004 ER PT J AU Morris, GM Coderre, JA Micca, PL Lombardo, DT Hopewell, JW AF Morris, GM Coderre, JA Micca, PL Lombardo, DT Hopewell, JW TI Boron neutron capture therapy of the rat 9L gliosarcoma: evaluation of the effects of shark cartilage SO BRITISH JOURNAL OF RADIOLOGY LA English DT Article ID TUMOR ANGIOGENESIS; INHIBITOR; NEOVASCULARIZATION; TNP-470; GROWTH; MODEL; BORONOPHENYLALANINE; ANGIOSTATIN AB A number of anti-angiogenic substances are now under evaluation, both experimentally and clinically, as potential agents for the treatment of cancer. It has recently been demonstrated that anti-angiogenic agents can increase the therapeutic potential of photon irradiation in a range of tumour models. In the present communication a preliminary assessment is made of the effects of shark cartilage on the response of the rat 9L gliosarcoma to boron neutron capture therapy (BNCT). Shark cartilage was administered orally as an aqueous suspension at a daily dose of similar to 2000 mg kg(-1) body weight. The mean survival time of rats receiving no treatment was 20.7+/-0.5 days post intracranial tumour implantation. Administration of shark cartilage alone extended the survival time. Two of the rats treated with shark cartilage were healthy and fully active at the end of the evaluation period (43 days post implantation). At autopsy the brain tumours of these animals were a factor of similar to 4 smaller than controls. In a repeat study with shark cartilage alone the survival time was extended by approximately 30%. After boronophenylalanine-mediated BNCT, with or without shark cartilage, the survival time of rats that eventually became moribund was increased by a factor of similar to 2 relative to controls. In both treatment groups similar to 20% of rats were healthy at 1 year after BNCT. There was no evidence of residual tumour at post-mortem It was concluded that shark cartilage, when given alone, significantly increased the survival time of tumour-bearing rats, presumably owing to an antiangiogenic effect. However, the survival data suggested that boronophenylalanine-mediated BNCT did not appear to be enhanced by the administration of shark cartilage. C1 Univ Oxford, Churchill Hosp, Res Inst, Oxford OX3 7LJ, England. Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. RP Morris, GM (reprint author), Univ Oxford, Churchill Hosp, Res Inst, S Parks Rd, Oxford OX3 7LJ, England. NR 27 TC 3 Z9 3 U1 0 U2 3 PU BRITISH INST RADIOLOGY PI LONDON PA 36 PORTLAND PLACE, LONDON W1N 4AT, ENGLAND SN 0007-1285 J9 BRIT J RADIOL JI Br. J. Radiol. PD APR PY 2000 VL 73 IS 868 BP 429 EP 434 PG 6 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 312PA UT WOS:000086950600013 PM 10844870 ER PT J AU LeMone, MA Grossman, RL Coulter, RL Wesley, ML Klazura, GE Poulos, GS Blumen, W Lundquist, JK Cuenca, RH Kelly, SF Brandes, EA Oncley, SP McMillen, RT Hicks, BB AF LeMone, MA Grossman, RL Coulter, RL Wesley, ML Klazura, GE Poulos, GS Blumen, W Lundquist, JK Cuenca, RH Kelly, SF Brandes, EA Oncley, SP McMillen, RT Hicks, BB TI Land-atmosphere interaction research, early results, and opportunities in the Walnut River Watershed in southeast Kansas: CASES and ABLE SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID CONVECTIVE BOUNDARY-LAYER; PROGRAM; PROJECT; WSR-88D; TURBULENCE; FACILITY; MOISTURE; SUPPORT; WEATHER; BOREAS AB This paper describes the development of the Cooperative Atmosphere Surface Exchange Study (CASES), its synergism with the development of the Atmosphere Boundary Layer Experiments (ABLE) and related efforts, CASES field programs, some early results, and future plans and opportunities. CASES is a grassroots multidisciplinary effort to study the interaction of the lower atmosphere with the land surface, the subsurface. and vegetation over timescales ranging from nearly instantaneous to years. CASES scientists developed a consensus that observations should be taken in a watershed between 50 and 100 km across; practical considerations led to an approach combining long-term data collection with episodic intensive field campaigns addressing specific objectives that should always include improvement of the design of the long-term instrumentation. In 1997, long-term measurements were initiated in the Walnut River Watershed east of Wichita, Kansas. Argonne National Laboratory started setting up the ABLE array. The first of the long-term hydrological enhancements was installed starting in May by the Hydrologic Science Team of Oregon State University. CASES-97, the first episodic field effort, was held during April-June to study the role of surface processes in the diurnal variation of the boundary layer, to test radar precipitation algorithms, and to define relevant scaling for precipitation and soil properties. The second episodic experiment, CASES-99, was conducted during October 1999, and focused on the stable boundary layer. Enhancements to both the atmospheric and hydrological arrays continue. The data from and information regarding both the long-term and episodic experiments are available on the World Wide Web. Scientists are invited to use the data and to consider the Walnut River Watershed for future field programs. C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Univ Colorado, Program Atmospher & Ocean Studies, Boulder, CO 80309 USA. Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. Colorado Res Associates, Boulder, CO USA. Oregon State Univ, Dept Engn, Corvallis, OR 97331 USA. NOAA, Atmospher Turbulence & Diffus Div, Oak Ridge, TN USA. NOAA, Atmospher Res Lab, Silver Spring, MD USA. RP LeMone, MA (reprint author), Natl Ctr Atmospher Res, POB 3000, Boulder, CO 80307 USA. OI LUNDQUIST, JULIE/0000-0001-5490-2702 NR 62 TC 71 Z9 72 U1 0 U2 3 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 APR PY 2000 VL 81 IS 4 BP 757 EP 779 DI 10.1175/1520-0477(2000)081<0757:LIRERA>2.3.CO;2 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 300PY UT WOS:000086262400006 ER PT J AU Begnaud, ML Stakes, DS AF Begnaud, ML Stakes, DS TI Constraining continental margin seismicity by extending on-shore seismograph stations to critical off-shore sites SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID OCEAN-BOTTOM SEISMOMETER; CALIFORNIA; EARTHQUAKE AB The westernmost North American plate margin in Central California includes major faults with both onshore and offshore segments. Prior to deployment during 1997 and 1998 of a suite of ocean-bottom seismometers within Monterey Bay, the distribution and focal mechanisms of offshore earthquakes were poorly constrained. The use of ocean-bottom seismic stations improves the accuracy of locations for events in Monterey Bay, especially for those far offshore, and permits more robust focal mechanism solutions by reducing uncertainties in strike, dip, and rake. These initial results, using U.S. Geological Survey crustal velocity models and location parameters, reduce the apparent scatter of seismic events and focal mechanisms, and the more consistent solutions provide valuable information on fault characteristics for the San Gregorio fault (SGF) and Monterey Bay fault zone (MBFZ). Most seismic events are relocated to the northern section of the SGF defining a zone of compressional deformation and relatively high microseismicity. The MBFZ is the source for fewer, but important and well-located events. Surprisingly, no events were observed on the southern SGF offshore of Carmel and Pebble Beach, despite the well-defined trace of the San Gregorio along Carmel Canyon. C1 Monterey Bay Aquarium Res Inst, Moss Landing, CA 95039 USA. RP Begnaud, ML (reprint author), Univ Calif Los Alamos Natl Lab, EES-3,MS D408, Los Alamos, NM 87545 USA. NR 33 TC 3 Z9 3 U1 1 U2 1 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 APR PY 2000 VL 90 IS 2 BP 414 EP 424 DI 10.1785/0119990115 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 314LU UT WOS:000087058000013 ER PT J AU Ichinose, GA Goldstein, P Rodgers, AJ AF Ichinose, GA Goldstein, P Rodgers, AJ TI Relative importance of near-, intermediate- and far-field displacement terms in layered Earth synthetic seismograms SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID SKULL-MOUNTAIN; DEFORMATION; WAVE AB Waveform modeling and moment tensor inversion commonly assume only the far-field response to the seismic source. However, for certain frequencies and distances the near- and intermediate-field terms of the Earth's response becomes important. We developed a criterion to estimate the relative importance of these terms for horizontally layered Earth models by comparing reflectivity synthetic seismograms, computed with just the far-field response (far-field terms only), with the complete response (all terms included). The frequency and range dependent differences of these two responses are quantified by measuring the difference between synthetics for regional and local earthquake scenarios, the 1992 Little Skull Mountain, Nevada (M-W 5.7) and 1997 Calico Hills, Nevada (M-W 4.0) earthquakes. For these crustal earthquakes, we found that the near-field term becomes important when the minimum frequency, f(n) (Hz) of the simulation at hypocentral distance r (km) is f(n) = gamma cr(-1) where a reasonable crustal velocity for c is 5.8 km/sec and gamma is the fraction of a wavelength estimated in this study to be approximate to 0.6. The far-field response converges to the complete response for frequencies greater than f(n). C1 Univ Calif Lawrence Livermore Natl Lab, Geophys & Global Secur Div, Livermore, CA 94550 USA. Univ Nevada, Reno Seismol Lab, Reno, NV 89557 USA. RP Ichinose, GA (reprint author), Univ Calif Lawrence Livermore Natl Lab, Geophys & Global Secur Div, Mail Code L-206, Livermore, CA 94550 USA. RI Rodgers, Arthur/E-2443-2011; Ichinose, Gene/I-4420-2016 OI Ichinose, Gene/0000-0003-2081-9825 NR 20 TC 7 Z9 7 U1 0 U2 3 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 APR PY 2000 VL 90 IS 2 BP 531 EP 536 DI 10.1785/0119990134 PG 6 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 314LU UT WOS:000087058000022 ER PT J AU Dziewinski, J Marczak, S AF Dziewinski, J Marczak, S TI Fighting the nitrates SO CHEMICAL INNOVATION LA English DT Article ID SUPERCRITICAL WATER; DRINKING-WATER; WASTE-WATER; DENITRIFICATION; DESTRUCTION; OXIDATION; REMOVAL; REDUCTION; PLATINUM; NITRITE C1 Univ Calif Los Alamos Natl Lab, Environm Sci & Waste Technol Div, Los Alamos, NM 87545 USA. RP Dziewinski, J (reprint author), Univ Calif Los Alamos Natl Lab, Environm Sci & Waste Technol Div, E-ET,Mail Stop J514,POB 1663, Los Alamos, NM 87545 USA. NR 37 TC 2 Z9 2 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1527-4799 J9 CHEM INNOV JI Chem. Innov. PD APR PY 2000 VL 30 IS 4 BP 33 EP 39 PG 7 WC Chemistry, Applied SC Chemistry GA 303JZ UT WOS:000086419900007 ER PT J AU Gong, XY Liu, J Baskaran, S Voise, RD Young, JS AF Gong, XY Liu, J Baskaran, S Voise, RD Young, JS TI Surfactant-assisted processing of carbon nanotube/polymer composites SO CHEMISTRY OF MATERIALS LA English DT Article ID FIELD-EMISSION; NANOTUBES AB Interfacial interaction is one of the most critical issues in carbon nanotube/polymer composites. In this paper the role of nonionic surfactant is investigated. With the surfactant as the processing aid, the addition of only 1 wt % carbon nanotubes in the composite increases the glass transition temperature from 63 degrees C to 88 degrees C. The elastic modulus is also increased by more than 30%. In contrast, the addition of carbon nanotubes without the surfactant only has moderate effects on the glass transition temperature and on the mechanical properties. This work points to the pathways to improve dispersion and to modify interfacial bonding in carbon nanotube/polymer composites. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Liu, J (reprint author), Pacific NW Natl Lab, Battelle Blvd, Richland, WA 99352 USA. NR 15 TC 663 Z9 718 U1 12 U2 187 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 APR PY 2000 VL 12 IS 4 BP 1049 EP 1052 DI 10.1021/cm9906396 PG 4 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 308DY UT WOS:000086696300026 ER PT J AU Ferrere, S AF Ferrere, S TI New photosensitizers based upon [Fe(L)(2)(CN)(2)] and [Fe(L)(3)](L = substituted 2,2 '-bipyridine): Yields for then photosensitization of TiO2 and effects on the band selectivity SO CHEMISTRY OF MATERIALS LA English DT Article ID TITANIUM-DIOXIDE FILMS; POLYPYRIDINE COMPLEXES; ELECTRON INJECTION; SENSITIZING DYE; EXCITED-STATES; NANOCRYSTALLINE; RUTHENIUM(II); SOLVATION AB Our recent report of the sensitization of TiO2 by [Fe(4,4'-dicarboxylic acid-2,2'-bipyridine)(2)(CN)(2)] introduced iron(II) bipyridyl complexes as fundamentally interesting and practical alternatives to their ruthenium analogues in the dye-sensitized solar cell (Ferrere and Gregg, J. Am. Chem. Sec. 1998, 120, 843). Here we detail how structural changes to the bipyridyl ligand L in [Fe(L)(2)(CN)(2)] affect photosensitization yields. We also explore the effect of solvent and solvent additives on the unique absorbance band selectivity of [Fe(4,4'-dicarboxylic acid-2,2'-bipyridine)(2)(CN)(2)] on TiO2. We demonstrate that solvent conditions can affect the relative photocurrent contributions from the two absorption bands of the complex, and suggest that it is related to changes in driving force for electron injection from the lower energy MLCT band. C1 Natl Renewable Energy Lab, Ctr Basic Sci, Golden, CO 80401 USA. RP Ferrere, S (reprint author), Natl Renewable Energy Lab, Ctr Basic Sci, 1617 Cole Blvd, Golden, CO 80401 USA. NR 17 TC 93 Z9 94 U1 2 U2 15 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 APR PY 2000 VL 12 IS 4 BP 1083 EP 1089 DI 10.1021/cm990713k PG 7 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 308DY UT WOS:000086696300032 ER PT J AU Kriesel, JW Tilley, TD AF Kriesel, JW Tilley, TD TI Synthesis and chemical functionalization of high surface area dendrimer-based xerogels and their use as new catalyst supports SO CHEMISTRY OF MATERIALS LA English DT Article ID ORGANIC-INORGANIC MATERIALS; TITANIUM-SILICA CATALYST; BRIDGED POLYSILSESQUIOXANES; MESOPOROUS SILICA; BUILDING-BLOCKS; MIXED OXIDES; EPOXIDATION; MULTILAYER; COMPLEXES; FILMS AB Second- and third-generation alkoxysilyl-terminated carbosilane dendrimers have been used as building blocks for the synthesis of high surface area xerogels, which were characterized by Si-29 CP MAS NMR spectroscopy, nitrogen adsorption/desorption porosimetry, IR spectroscopy, transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Thus, the acid-catalyzed hydrolysis of Si[CH2CH2CH2Si(CH2CH2Si(OEt)(3))(3)](4) (G2-(OEt)(36)) and Si{CH2CH2CH2Si[CH2CH2CH2Si(CH2CH2Si(OEt)(3))(3)](3)}(4) (G3-(OEt)(108)) in benzene solution yielded monolithic gels. The resulting xerogels, X-G2(benz) and X-G3(benz), have surface areas of 600 and 800 m(2)/g, respectively. The surface area of these xerogels increase with increasing dendritic radii, suggesting that the dendrimer building blocks of X-G2(benz) are compressed onto one another to a greater extent than the corresponding dendrimers that comprise X-G3(benz). The isolation of monoliths from benzene solution suggests that; the hydrophobic interior of the dendrimers keeps the polymerizing species in solution. Other precursors such as TEOS, 4,4'-bis(triethoxysilyl)biphenyl, and Si(CH2CH2Si(OEt)(3))(4) (G1-(OEt)(12)) did not yield monolithic gels after hydrolysis in benzene. Dendrimers with fewer alkoxysilyl groups at the periphery (G2-(OEt)(24)Me-12 and G3-(OEt)(72)Me-36) were hydrolyzed in THF or benzene to materials with no appreciable surface area. After obtaining wet monolithic gels from the acid-catalyzed hydrolyses of G2-(OEt)(36) and G3-(OEt)(108) in benzene, postgelation processing was conducted by heating the monoliths in hot toluene for 48 h. After solvent evaporation, this procedure gave xerogels X-G2(HT) and X-G3(HT), which possess surface areas of 1300 and 1000 m(2)/g, respectively. These aerogel-like gels were treated with Ti((OPr)-Pr-i)(4) to yield X-G2(Ti) and X-G3(Ti). Additionally, X-G2(HT) was treated with Ti[OSi((OBu)-Bu-t)(3)](4) to yield X-Ga-Ti/Si. All three gels were subsequently used as catalysts in the epoxidation of cylcohexene. These gels were shown to be very selective and significantly more active (in terms of yield and initial rate) than the Shell catalyst derived from treatment of silica with Ti((OPr)-Pr-i)(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 Tilley, TD (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 57 TC 39 Z9 41 U1 1 U2 15 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 APR PY 2000 VL 12 IS 4 BP 1171 EP 1179 DI 10.1021/cm000098g PG 9 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 308DY UT WOS:000086696300045 ER PT J AU Zhang, T Hou, JD Tang, BY Kwok, TK Zeng, ZM Brown, IG Chu, PK AF Zhang, T Hou, JD Tang, BY Kwok, TK Zeng, ZM Brown, IG Chu, PK TI The effect of mesh anode on cathodic arc in focusing magnetic field SO CHINESE PHYSICS LA English DT Article ID SPOT MOTION; DEPOSITION; COATINGS AB The performance and characteristics of a cathodic are deposition apparatus consisting of a titanium cathode, an anode with and without a tungsten mesh, and a coil producing a focusing magnetic field between the anode and cathode are investigated. The are voltage V(a) is measured with a fixed are current. The relationship between V(a) and the magnetic field B with and without a mesh is obtained. In addition, the relationship between the are current I(a) and V(c), the voltage to which the artificial transmission line was charged, is measured with and without the mesh to determine the minimum ignition voltage for the are. The are resistance increases with the focusing magnetic strength B and decreases when using the mesh. Our results indicate that the high transparency and large area of the mesh allows a high plasma flux to penetrate the anode from the cathodic are. The mesh also stabilizes the cathodic are and gives better performance when used in concert with a focusing magnetic field. C1 Beijing Normal Univ, Inst Low Energy Nucl Phys, Beijing 100875, Peoples R China. City Univ Hong Kong, Dept Phys & Mat Sci, Kowloon, Hong Kong, Peoples R China. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Zhang, T (reprint author), Beijing Normal Univ, Inst Low Energy Nucl Phys, Beijing 100875, Peoples R China. RI Chu, Paul/B-5923-2013 OI Chu, Paul/0000-0002-5581-4883 NR 9 TC 4 Z9 4 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 1009-1963 J9 CHINESE PHYS JI Chin. Phys. PD APR PY 2000 VL 9 IS 4 BP 279 EP 283 PG 5 WC Physics, Multidisciplinary SC Physics GA 305DV UT WOS:000086524900006 ER PT J AU Roh, Y Lee, SY Elless, MP Foss, JE AF Roh, Y Lee, SY Elless, MP Foss, JE TI Incorporation of radioactive contaminants into pyroaurite-like phases by electrochemical synthesis SO CLAYS AND CLAY MINERALS LA English DT Article DE coprecipitation; groundwater remediation; pyroaurite; technetium; uranium; zero-valent iron ID FE(II)FE(III) HYDROXY-CARBONATE; ZERO-VALENT IRON; GREEN RUST; HEAVY-METALS; GROUNDWATER AB During electrochemical remediation of radionuclide, U-235, U-228, and Tc-99-contaminated aqueous solutions, pyroaurite-like phases, ideally [M(II)M(III)(OH)(16)CO3. 4H(2)O] where M = Fe, were synthesized following coprecipitation with iron from metal iron electrodes. The effect of radionuclides on the transformation of amorphous precipitates to crystalline pyroaurite-like phases was investigated using X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray analysis, Fourier-transform infrared (FTIR) spectroscopy, and fluorescence spectroscopy. The synthetic iron carbonate hydroxide phases showed primary XRD peaks at 0.7 and 0.35 nm and FTIR spectra that indicated the presence of a brucite-like sheet structure with carbonate anions occupying the interlayer. Divalent and trivalent iron, eroded from the electrode, occupies the octahedral sites of the brucite-like sheets. The carbonate anions in the interlayer balance the excess positive charge from isomorphous substitution of the Fe2+ or Fe3+ by reduced uranium (U4+) and technetium (Tc4+). Because of the lower solubility associated with crystalline phases than amorphous phases, incorporation of radioactive contaminants into pyroaurite-like phases by electrochemical syntheses represents a more effective approach for removing U and Tc from contaminated aqueous solutions than traditional technologies. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Plant & Soil Sci, Knoxville, TN 37996 USA. Edenspace Syst Corp, Reston, VA 20191 USA. RP Roh, Y (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. NR 24 TC 31 Z9 32 U1 3 U2 13 PU CLAY MINERALS SOCIETY PI BOULDER PA PO BOX 4416, BOULDER, CO 80306 USA SN 0009-8604 J9 CLAY CLAY MINER JI Clay Clay Min. PD APR PY 2000 VL 48 IS 2 BP 266 EP 271 DI 10.1346/CCMN.2000.0480213 PG 6 WC Chemistry, Physical; Geosciences, Multidisciplinary; Mineralogy; Soil Science SC Chemistry; Geology; Mineralogy; Agriculture GA 312PJ UT WOS:000086951400013 ER PT J AU Leemans, W Chattopadhyay, S Esarey, E Zholents, A Zolotorev, M Chin, A Schoenlein, R Shank, CV AF Leemans, W Chattopadhyay, S Esarey, E Zholents, A Zolotorev, M Chin, A Schoenlein, R Shank, CV TI Femtosecond X-ray generation through relativistic electron beam-laser interaction SO COMPTES RENDUS DE L ACADEMIE DES SCIENCES SERIE IV PHYSIQUE ASTROPHYSIQUE LA English DT Article DE X-ray; femtosecond; laser; electron beam; Thomson scattering; diffraction; laser wakefield acceleration ID 90-DEGREES THOMSON SCATTERING; PLASMA-BASED ACCELERATORS; STRUCTURAL DYNAMICS; LINEAR COLLIDERS; PULSES; DIFFRACTION; EXCITATION; INJECTION; BUNCH AB Methods for generating ultra-short X-rays using the interaction of intense laser pulses with relativistic electron beams, and their application to measuring ultra-fast phenomena in solid stare materials, are reviewed. Two different methods that use a long electron bunch and short laser pulse are discussed: Thomson scattering and optical slicing which have been implemented on linac and storage ring beams, respectively. The possibility of generating ultrashort electrons bunches from laser-plasma injectors is discussed. (C) 2000 Academie des sciences/Editions scientifiques et medicales Elsevier SAS. C1 Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Ctr Beam Phys, Div Accelerator & Fus Res, Berkeley, CA 94720 USA. Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Leemans, W (reprint author), Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Ctr Beam Phys, Div Accelerator & Fus Res, 1 Cyclotron Rd, Berkeley, CA 94720 USA. RI Schoenlein, Robert/D-1301-2014 OI Schoenlein, Robert/0000-0002-6066-7566 NR 44 TC 17 Z9 18 U1 2 U2 2 PU EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER PI PARIS CEDEX 15 PA 23 RUE LINOIS, 75724 PARIS CEDEX 15, FRANCE SN 1296-2147 J9 CR ACAD SCI IV-PHYS JI C. R. Acad. Sci. Ser. IV-Phys. Astrophys. PD APR PY 2000 VL 1 IS 3 BP 279 EP 296 DI 10.1016/S1296-2147(00)00149-9 PG 18 WC Astronomy & Astrophysics; Physics, Multidisciplinary SC Astronomy & Astrophysics; Physics GA 372CF UT WOS:000165215500002 ER PT J AU Morgan, DL Neely, JR Vantine, HC AF Morgan, DL Neely, JR Vantine, HC TI Periodic boundary conditions in a 3D hydro code SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article; Proceedings Paper CT 1st International Conference on Modern Trends in Computational Physics (MTCP 98) CY JUN 15-20, 1998 CL DUBNA, RUSSIA SP Inst Nucl Res Lab Comp Techn & Automat, Russian Univ Peoples Friendship, Minis Sci & Technol, Russia & Russian Fdn Basic Res DE 3D hydrodynamics; periodic boundary conditions AB We have modified a 3D hydrodynamics code so that it has the capability to impose periodic boundary conditions on the problem being considered. This capability allows it to treat only a basic symmetry unit of the problem when translational or rotational periodic symmetries are present. The code has been run successfully for two test problems involving rotational symmetries. (C) 2000 Elsevier Science B.V. Ail rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Morgan, DL (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NR 2 TC 0 Z9 0 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD APR PY 2000 VL 126 IS 1-2 BP 131 EP 136 PG 6 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 292FX UT WOS:000085784500025 ER PT J AU Snodgrass, JW Komoroski, MJ Bryan, AL Burger, J AF Snodgrass, JW Komoroski, MJ Bryan, AL Burger, J TI Relationships among isolated wetland size, hydroperiod, and amphibian species richness: Implications for wetland regulations SO CONSERVATION BIOLOGY LA English DT Article ID COMMUNITY STRUCTURE; COASTAL-PLAIN AB Wetland development within the United States is regulated primarily by size. Decisions concerning wetland destruction or conservation are therefore based in part on three inherent assumptions: (1) small wetlands contain water for short portions of the year; (2) small wetlands support few species; and (3) species found in small wetlands are also found in larger wetlands. We tested these assumptions using data on wetland size, relative hydroperiod (drying scores), and relative species richness of amphibians in depression wetlands of the southeastern United States. We found a significant (p = 0.03) but weak (r(2) = 0.05) relationship between hydroperiod and wetland size and no relationship (p = 0.48) between amphibian species richness and wetland size. Furthermore, synthetic models of lentic communities predict that short-hydroperiod wetlands support a unique group of species. Empirical investigations support this prediction. Our results indicate that hydroperiod length should be included as a primary criterion in wetland regulations. We advocate a landscape approach to wetlands regulation, focused in part on conserving a diversity of wetlands that represent the entire hydroperiod gradient. C1 Rutgers State Univ, Div Life Sci, Piscataway, NJ 08854 USA. Rutgers State Univ, Consortium Risk Evaluat Stakeholder Participat, Environm & Occupat Hlth Sci Inst, Piscataway, NJ 08854 USA. Univ Georgia, Savannah River Ecol Lab, Aiken, SC 29802 USA. RP Snodgrass, JW (reprint author), Towson Univ, Dept Biol, Towson, MD 21252 USA. RI Snodgrass, Joel/C-5288-2016; OI Snodgrass, Joel/0000-0002-4436-8750 NR 16 TC 190 Z9 198 U1 5 U2 61 PU BLACKWELL SCIENCE INC PI MALDEN PA 350 MAIN ST, MALDEN, MA 02148 USA SN 0888-8892 J9 CONSERV BIOL JI Conserv. Biol. PD APR PY 2000 VL 14 IS 2 BP 414 EP 419 DI 10.1046/j.1523-1739.2000.99161.x PG 6 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 300WD UT WOS:000086275800010 ER PT J AU Bond, LJ Kepler, WF Frangopol, DM AF Bond, LJ Kepler, WF Frangopol, DM TI Improved assessment of mass concrete dams using acoustic travel time tomography. Part I - theory SO CONSTRUCTION AND BUILDING MATERIALS LA English DT Article DE non-destructive testing; concrete; dams; tomography ID REINFORCED-CONCRETE; WAVE; ATTENUATION; SCATTERING AB This is the first part of an investigation on improved assessment of mass concrete dams using Acoustic Travel Time Tomography (ATTT). It presents the concept and basic science for ATTT. ATTT combines aspects of ultrasonic measurements previously used for material characterization, ultrasonic methods applied to test concrete and features of methods used in shallow seismic surveys. This science/technology is integrated into a system that records travel time data and applies tomography software. The resulting tomographs have the potential to provide cross-sectional images of the structure that can be used to locate cracks, identify regions of structural damage, and other anomalies deep inside a massive concrete structure. Results from initial laboratory and field studies obtained with a system that embodies the approach presented in this paper and which provides proof-of-concept data, are presented in a companion paper (Kepler WF, Bond LJ, Frangopol DM. Improved assessment of mass concrete dams using acoustic travel time tomography. Part II - applications. Constr Build Mater, 2000; Vol. 14, No. 3, pp. 147-156). (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Pacific NW Lab, Richland, WA 99352 USA. US Bur Reclamat, Denver Fed Ctr, Lakewood, CO 80225 USA. Univ Colorado, Dept Civil Environm & Architectural Engn, Boulder, CO 80309 USA. NR 61 TC 19 Z9 22 U1 0 U2 3 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0950-0618 J9 CONSTR BUILD MATER JI Constr. Build. Mater. PD APR PY 2000 VL 14 IS 3 BP 133 EP 146 DI 10.1016/S0950-0618(00)00014-3 PG 14 WC Construction & Building Technology; Engineering, Civil; Materials Science, Multidisciplinary SC Construction & Building Technology; Engineering; Materials Science GA 315MV UT WOS:000087118300002 ER PT J AU Kepler, WF Bond, LJ Frangopol, DM AF Kepler, WF Bond, LJ Frangopol, DM TI Improved assessment of mass concrete dams using acoustic travel time tomography. Part II - application SO CONSTRUCTION AND BUILDING MATERIALS LA English DT Article DE non-destructive testing; concrete; dam; tomography AB The aging of key elements of our civil infrastructure, including dams, is presenting new challenges for the development of methodology that will adequately predict remaining safe life, and identify those structures where remedial action is required. To meet this need, a new approach for non-destructive testing of large concrete dams has been developed. It combines aspects of ultrasonic non-destructive testing and seismic surveying in a new methodology 'Acoustic Travel Time Tomography' (ATTT). This is the second part of an investigation on improved assessment of mass concrete dams using ATTT. A companion paper [Bond LJ, Kepler WF, Frangopol, DM. Improved assessment of mass concrete dams using acoustic travel time tomography. Part I theory. Constr Build Mater 2000; Vol. 14, No. 3, pp. 133-146] focused on the background of the physics of ATTT. ATTT was tested in the laboratory, modified for large-scale testing, then evaluated for reliability. This study reports the application of the methodology, instrumentation, and data analysis techniques developed during the study. The research demonstrates that ATTT can locate and characterize cracks, voids and other anomalies deep within a mass concrete dam. The results at each stage of the study have shown that ATTT is a potentially highly accurate testing procedure, and that it is uniquely suited to the evaluation of large concrete darns. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 US Bur Reclamat, Denver Fed Ctr, Lakewood, CO 80225 USA. Pacific NW Lab, Richland, WA 99352 USA. Univ Colorado, Dept Civil Environm & Architectural Engn, Boulder, CO 80309 USA. NR 29 TC 20 Z9 22 U1 3 U2 6 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0950-0618 J9 CONSTR BUILD MATER JI Constr. Build. Mater. PD APR PY 2000 VL 14 IS 3 BP 147 EP 156 DI 10.1016/S0950-0618(00)00013-1 PG 10 WC Construction & Building Technology; Engineering, Civil; Materials Science, Multidisciplinary SC Construction & Building Technology; Engineering; Materials Science GA 315MV UT WOS:000087118300003 ER PT J AU Sasaki, T Burr, B AF Sasaki, T Burr, B TI International Rice Genome Sequencing Project: the effort to completely sequence the rice genome SO CURRENT OPINION IN PLANT BIOLOGY LA English DT Review ID PRE-MESSENGER-RNA; PREDICTION; GENE; DNA AB The International Rice Genome Sequencing Project (IRGSP) involves researchers from ten countries who are working to completely and accurately sequence the rice genome within a short period. Sequencing uses a map-based clone-by-clone shotgun strategy; shared bacterial artificial chromosome/ P1-derived artificial chromosome libraries have been constructed from Oryra sativa ssp. japonica variety 'Nipponbare'. End-sequencing, fingerprinting and marker-aided PCR screening are being used to make sequence-ready contigs. Annotated sequences are immediately released for public use and are made available with supplemental information at each IRGSP member's website. The IRC;SP works to promote the development of rice and cereal genomics in addition to producing genome sequence data. C1 Natl Inst Agrobiol Resources, Rice Genome Res Program, Tsukuba, Ibaraki 3058602, Japan. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Sasaki, T (reprint author), Natl Inst Agrobiol Resources, Rice Genome Res Program, 1-2 Kannondai 2 Chome, Tsukuba, Ibaraki 3058602, Japan. NR 23 TC 204 Z9 227 U1 3 U2 23 PU CURRENT BIOLOGY LTD PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 1369-5266 J9 CURR OPIN PLANT BIOL JI Curr. Opin. Plant Biol. PD APR PY 2000 VL 3 IS 2 BP 138 EP 141 DI 10.1016/S1369-5266(99)00047-3 PG 4 WC Plant Sciences SC Plant Sciences GA 296CE UT WOS:000086004800008 PM 10712951 ER PT J AU Garcia, A AF Garcia, A TI Electron-capture decays of Tc-100 and In-116 and nuclear structure relevant for 2 beta decays SO CZECHOSLOVAK JOURNAL OF PHYSICS LA English DT Article; Proceedings Paper CT Workshop on Calculation of Double-Beta-Decay Matrix Elements (MEDEX 99) CY JUL 20-23, 1999 CL PRAGUE, CZECH REPUBLIC ID DOUBLE-BETA-DECAY; STATES; MO-100 AB Both Mo-100 and Cd-116 are double-beta-decay candidates, whose intermediate (virtual) state is a nucleus with J(pi) = 1(+) in the ground state. Consequently, in these cases one can measure the 'single-beta-decay' matrix elements in addition to the 2v-decay rate and test models in a more stringent way. We have measured the electron-capture decays of Tc-100 and In-116 which show that: a) the 'ground state dominance hypothesis' works very well; b) deformation plays a role which cannot be neglected in QRPA calculations. QRPA predictions work better in the spherical A = 116 system than in the 'transition' A = 100 system. C1 Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. Lawrence Berkeley Natl lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Garcia, A (reprint author), Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. OI Garcia, Alejandro/0000-0001-6056-6645 NR 6 TC 0 Z9 0 U1 0 U2 0 PU CZECHOSLOVAK JNL OF PHYSICS PI PRAGUE PA FYZIKALNI USTAV AV NA SLOVANCE 2, PRAGUE 180 40, CZECH REPUBLIC SN 0011-4626 J9 CZECH J PHYS JI Czech. J. Phys. PD APR PY 2000 VL 50 IS 4 BP 485 EP 487 DI 10.1023/A:1022836507410 PG 3 WC Physics, Multidisciplinary SC Physics GA 315CT UT WOS:000087095600005 ER PT J AU Erdemir, A Eryilmaz, OL Nilufer, IB Fenske, GR AF Erdemir, A Eryilmaz, OL Nilufer, IB Fenske, GR TI Effect of source gas chemistry on tribological performance of diamond-like carbon films SO DIAMOND AND RELATED MATERIALS LA English DT Article; Proceedings Paper CT 10th European Conference on Diamond, Diamond-Like Materials, Nitrides and Silicon Carbide (Diamond 1999) CY SEP 12-17, 1999 CL PRAGUE, CZECH REPUBLIC SP AIXTRON, Daimler-Chrysler, Elsevier Sci DE diamond-like carbon; source gas chemistry; super-low friction and wear ID COATINGS; WEAR; BEHAVIOR; HYDROGEN; MECHANISM; FRICTION AB In this study, we investigated the effects of various source gases (methane, ethane? ethylene, acetylene, and methane + hydrogen) on the friction and wear performance of diamond-like carbon (DLC films produced from the source gases. Specifically, we described the anomalous nature and fundamental friction and near mechanisms of DLC films derived from gas discharge plasmas with very low to very high hydrogen content. The films were deposited on steel substrates by a plasma-enhanced chemical vapor deposition process at room temperature and the tribological tests were performed in dry nitrogen. The tribological tests revealed a close correlation between the source gas chemistry and the friction and wear coefficients of the DLC films. Specifically, films grown in source gases with higher hydrogen-to-carbon ratios had much lower friction coefficients and wear rates than did films derived from source gases with lower hydrogen-to-carbon ratios. The lowest friction coefficient (0.002) was achieved with a him derived from 25% methane +75% hydrogen, whereas a coefficient of 0.15 was seen in films derived from acetylene. Similar correlations were observed for wear rates. Films derived from hydrogen-rich plasmas had the least wear, whereas films derived from pure acetylene suffered the highest wear. We used a combination of scanning and transmission electron microscopy and Raman spectroscopy to characterize the structural chemistry of the resultant DLC films. 2000 Elsevier Science S.A. All rights reserved. C1 Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. Istanbul Tech Univ, Dept Mat & Met Engn, TR-80626 Istanbul, Turkey. RP Erdemir, A (reprint author), Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. EM erdemir@anl.gov NR 35 TC 77 Z9 81 U1 0 U2 11 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-9635 J9 DIAM RELAT MATER JI Diam. Relat. Mat. PD APR-MAY PY 2000 VL 9 IS 3-6 BP 632 EP 637 DI 10.1016/S0925-9635(99)00361-1 PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA 320CA UT WOS:000087382400081 ER PT J AU Garten, CT Cooper, LW Post, WM Hanson, PJ AF Garten, CT Cooper, LW Post, WM Hanson, PJ TI Climate controls on forest soil C isotope ratios in the Southern Appalachian Mountains SO ECOLOGY LA English DT Article DE Appalachian Mountains, Southern; discrimination factors; elevation gradient; forest soil; isotopic fractionation; soil organic carbon (SOC); soil organic matter (SOM); stable isotopes; temperature; effects on delta C-13 ID ORGANIC-MATTER; CARBON-ISOTOPE; THEORETICAL-ANALYSIS; NATURAL ABUNDANCE; TEMPERATE FOREST; C-13 ABUNDANCE; DECOMPOSITION; TURNOVER; STORAGE; CO2 AB A large portion of terrestrial carbon (C) resides in soil organic carbon (SOC). The dynamics of this large reservoir depend on many factors, including climate. Measurements of C-13:C-12 ratios, C concentrations, and C:N ratios at six forest sites in the Southern Appalachian Mountains (USA) were used to explore several hypotheses concerning the relative importance of factors that control soil organic matter (SOM) decomposition and SOC turnover. Mean delta(13)C values increased with soil depth and decreasing C concentrations along a continuum from fresh litter inputs to more decomposed soil constituents. Data from the six forest sites, in combination with data from a literature review, indicate that the extent of change in delta(13)C values from forest litter inputs to mineral soil (similar to 20 cm deep) is significantly associated with mean annual temperature. The findings support a conceptual model of vertical changes in forest soil delta(13)C values, C concentrations, and C:N ratios that are interrelated through climate controls on decomposition. We hypothesize that, if other environmental factors (like soil moisture) are not limiting, then temperature and litter quality indirectly control the extent of isotopic fractionation during SOM decomposition in temperate forest ecosystems. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Garten, CT (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. RI Hanson, Paul J./D-8069-2011; Post, Wilfred/B-8959-2012; Cooper, Lee/E-5251-2012 OI Hanson, Paul J./0000-0001-7293-3561; Cooper, Lee/0000-0001-7734-8388 NR 35 TC 87 Z9 89 U1 3 U2 32 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 1990 M STREET NW, STE 700, WASHINGTON, DC 20036 USA SN 0012-9658 EI 1939-9170 J9 ECOLOGY JI Ecology PD APR PY 2000 VL 81 IS 4 BP 1108 EP 1119 DI 10.1890/0012-9658(2000)081[1108:CCOFSC]2.0.CO;2 PG 12 WC Ecology SC Environmental Sciences & Ecology GA 302EB UT WOS:000086351500020 ER PT J AU Liu, P Zhang, JG Tracy, CE Turner, JA AF Liu, P Zhang, JG Tracy, CE Turner, JA TI Electrochemical deposition of vanadium oxide in the presence of surfactants - A novel approach toward high-rate lithium battery cathodes SO ELECTROCHEMICAL AND SOLID STATE LETTERS LA English DT Article ID TEMPLATE SYNTHESIS; V2O5; INTERCALATION; ELECTRODES AB Porous vanadium oxide materials were prepared by electrochemical deposition in the presence of surfactants. Both scanning electron microscopy and ac impedance results indicated a large increase in surface area compared with a sample prepared without surfactants. X-ray diffraction and infrared spectroscopy results indicated that despite the difference in surface area these materials have similar structures. The vanadium oxide electrode prepared in the presence of surfactants showed improved rate performance when used as a cathode in lithium batteries, with a capacity of 220 mAh/g at a 5C rate. (C) 2000 The Electrochemical Society. S1099-0062(99)12-077-7. All rights reserved. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. Macro Energy Tech Inc, Redondo Beach, CA 90278 USA. RP Liu, P (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Liu, Ping/I-5615-2012 NR 17 TC 30 Z9 31 U1 0 U2 10 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 APR PY 2000 VL 3 IS 4 BP 163 EP 166 PG 4 WC Electrochemistry; Materials Science, Multidisciplinary SC Electrochemistry; Materials Science GA 297ZZ UT WOS:000086115300001 ER PT J AU Amine, K Yasuda, H Yamachi, M AF Amine, K Yasuda, H Yamachi, M TI Olivine LiCoPO4 as 4.8 V electrode material for lithium batteries SO ELECTROCHEMICAL AND SOLID STATE LETTERS LA English DT Article ID CATHODE MATERIALS; FRAMEWORKS; INSERTION AB Reversible extraction and insertion of lithium from and into olivine LiCoPO4 at 4.8 V vs. lithium have shown that this material is a good candidate for a high-voltage lithium-ion battery. Electrochemical extraction was limited to 0.42 lithium per formula unit, with a charge capacity of 86 mAh/g and a discharge capacity of 70 mAh/g. In this case, the material retains its structural integrity with a slight contraction of the unit cell upon cycling. The crystallinity of the electrode during charge and discharge processes was not affected, as deduced from the sharpness of the X-ray diffraction peaks of the cycled cathode material. (C) 2000 The Electrochemical Society. S1099-0062(99)11-055-1. All rights reserved. C1 Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. Japan Storage Battery Co Ltd, Minami Ku, Kyoto 601, Japan. RP Amine, K (reprint author), Argonne Natl Lab, Div Chem Technol, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Amine, Khalil/K-9344-2013 NR 17 TC 396 Z9 413 U1 23 U2 165 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 APR PY 2000 VL 3 IS 4 BP 178 EP 179 PG 2 WC Electrochemistry; Materials Science, Multidisciplinary SC Electrochemistry; Materials Science GA 297ZZ UT WOS:000086115300005 ER PT J AU Jankowiak, R Roberts, KP Small, GJ AF Jankowiak, R Roberts, KP Small, GJ TI Fluorescence line-narrowing detection in chromatography and electrophoresis SO ELECTROPHORESIS LA English DT Review DE chromatography; electrophoresis; capillary electrophoresis - fluorescence line-narrowing spectroscopy; analyte identification; on-line fluorescence detection; review ID THIN-LAYER CHROMATOGRAPHY; POLYACRYLAMIDE-GEL ELECTROPHORESIS; PERFORMANCE LIQUID-CHROMATOGRAPHY; POLYCYCLIC AROMATIC-HYDROCARBONS; TRANSFORM INFRARED SPECTROMETRY; CAPILLARY ZONE ELECTROPHORESIS; ELECTROSPRAY MASS-SPECTROMETRY; RAMAN-SPECTROSCOPIC DETECTION; BENZOPYRENE DNA-ADDUCTS; MAGNETIC-RESONANCE AB A review of the basic aspects of fluorescence line-narrowing spectroscopy (FLNS) and its coupling with thin-layer chromatography (TLC) and polyacrylamide gel electrophoresis (PAGE) for off-line high-resolution low temperature spectral characterization is discussed. This is followed by a description of the on-line interfacing of capillary electrophoresis (CE) and capillary electrochromatography (CEC) with FLN detection. CE/CEC-FLNS instrumentation and its applications for spectral identification of closely related analytes are also presented. Future prospects of micro and capillary high performance liquid chromatography (HPLC) with on-line high-resolution low temperature spectroscopic identification are considered. C1 Iowa State Univ Sci & Technol, Ames Lab, USDOE, Dept Chem, Ames, IA 50011 USA. RP Jankowiak, R (reprint author), Iowa State Univ Sci & Technol, Ames Lab, USDOE, Dept Chem, Ames, IA 50011 USA. FU NCI NIH HHS [P0I CA49210-05] NR 112 TC 20 Z9 20 U1 1 U2 8 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0173-0835 J9 ELECTROPHORESIS JI Electrophoresis PD APR PY 2000 VL 21 IS 7 BP 1251 EP 1266 DI 10.1002/(SICI)1522-2683(20000401)21:7<1251::AID-ELPS1251>3.0.CO;2-D PG 16 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 313WH UT WOS:000087022300003 PM 10826669 ER PT J AU Jensen, PK Pasa-Tolic, L Peden, KK Martinovic, S Lipton, MS Anderson, GA Tolic, N Wong, KK Smith, RD AF Jensen, PK Pasa-Tolic, L Peden, KK Martinovic, S Lipton, MS Anderson, GA Tolic, N Wong, KK Smith, RD TI Mass spectrometic detection for capillary isoelectric focusing separations of complex protein mixtures SO ELECTROPHORESIS LA English DT Article DE capillary isoelectric focusing Fourier transform ion cyclotron resonance mass spectrometry; proteome; complex biological mixture separation; Deinococcus radiodurans; Escherichia coli ID ESCHERICHIA-COLI K-12; 2-DIMENSIONAL ELECTROPHORESIS; IDENTIFICATION; PROTEOMES; MS; QUANTITATION; MOBILIZATION; TRANSFERRIN; GENOME AB Capillary isoelectric focusing (CIEF) can provide high-resolution separations of complex protein mixtures, but until recently it has primarily been used with conventional UV detection. This technique would be greatly enhanced by much more information-rich detection methods that can aid in protein characterization. We describe progress in the development of the combination of CIEF with Fourier transform ion cyclotron resonance (FTICR) mass spectrometry and its application to proteome characterization. Studies have revealed 400-1000 putative proteins in the mass range of 2-100 kDa from total injections of similar to 300 ng protein in single CIEF-FTICR analyses of cell lysates for both Escherichia coli (E. coli) and Deinococcus radiodurans (D. radiodurans). We also demonstrate the use of isotope labeling of the cell growth media to improve mass measurement accuracy and provide a means for quantitative proteome-wide measurements of protein expression. The ability to make such comprehensive and precise measurements of differences in protein expression in response to cellular perturbations should provide new insights into complex cellular processes. C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Smith, RD (reprint author), Pacific NW Lab, Environm Mol Sci Lab, POB 999,Mail Stop K8-98, Richland, WA 99352 USA. RI Smith, Richard/J-3664-2012; OI Smith, Richard/0000-0002-2381-2349; Wong, Kwong-Kwok/0000-0002-0375-6669 NR 37 TC 102 Z9 112 U1 0 U2 8 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0173-0835 J9 ELECTROPHORESIS JI Electrophoresis PD APR PY 2000 VL 21 IS 7 BP 1372 EP 1380 DI 10.1002/(SICI)1522-2683(20000401)21:7<1372::AID-ELPS1372>3.3.CO;2-P PG 9 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 313WH UT WOS:000087022300017 PM 10826683 ER PT J AU Stein, JR Meier, A AF Stein, JR Meier, A TI Accuracy of home energy rating systems SO ENERGY LA English DT Article AB We compared Home Energy Rating Systems (HERS) ratings and actual utility billing data for about 500 houses in four states. We found that HERS can, on average, predict annual energy cost accurately. However, on an individual house basis the agreement between predicted energy cost and actual energy cost was often poor, especially for older houses. Discrepancies between predicted and actual energy use have important implications for the true cost-effectiveness of HERS-recommended improvements. There was no clear relationship between rating score and actual energy cost. Given these results, HERS providers need to give consumers more information about accuracy and how to interpret ratings. They should also take greater advantage of the thousands of ratings that have been conducted in order to assess and improve HERS' ability to predict energy use. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Meier, A (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Bldg 90,Room 2000, Berkeley, CA 94720 USA. NR 14 TC 19 Z9 19 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0360-5442 J9 ENERGY JI Energy PD APR PY 2000 VL 25 IS 4 BP 339 EP 354 DI 10.1016/S0360-5442(99)00072-9 PG 16 WC Thermodynamics; Energy & Fuels SC Thermodynamics; Energy & Fuels GA 294HX UT WOS:000085906800004 ER PT J AU Etnier, EL King, JF Watson, AP AF Etnier, EL King, JF Watson, AP TI Chemical warfare materiel: Unique regulatory issues SO ENVIRONMENTAL MANAGEMENT LA English DT Article DE chemical warfare materiel; environmental media; Resource Conservation and Recovery Act; Comprehensive Environmental Response, Compensation, and Liability Act; health-based cleanup; restoration AB The US Army manages an extensive program of environmental restoration that is carried out primarily under authority of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), which establishes response authority for cleanup of inactive waste sites. The Resource Conservation and Recovery Act (RCRA) regulates the management and cleanup of hazardous materials at active hazardous waste facilities. Based on the definitions found in these acts, and corresponding promulgated regulations, environmental media contaminated with chemical warfare materiel (CWM) can be regulated as CERCLA "pollutants or contaminants" but do not appear to be regulated either as CERCLA hazardous substances or RCRA hazardous wastes. In those states that have not included CWM as hazardous materials in their RCRA programs, the RCRA requirements for management of hazardous waste would not strictly apply to any of the CWM. The Army has historically implemented procedures requiring that chemical warfare agents be managed as RCRA hazardous waste regardless of the concentration, physical form, or configuration of the agent. Such application of strict hazardous waste requirements to management of potentially nonhazardous CWM can result in remedial costs well out of proportion to potential human health and environmental benefits. Recent development of chronic toxicity values for the CWM has opened the door for development of cleanup and waste management standards for waste streams or media containing small residual amounts of CWM. Implementation of this health-based approach to management of CWM remediation wastes may, in part, help to reduce potentially unnecessary hazardous waste management costs for the nonhazardous CWM. C1 USA, Ctr Environm, Aberdeen Proving Ground, MD 21010 USA. Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37830 USA. RP Etnier, EL (reprint author), 1405 Whitower Dr, Knoxville, TN 37919 USA. NR 8 TC 0 Z9 0 U1 1 U2 4 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0364-152X J9 ENVIRON MANAGE JI Environ. Manage. PD APR PY 2000 VL 25 IS 4 BP 347 EP 356 DI 10.1007/s002679910027 PG 10 WC Environmental Sciences SC Environmental Sciences & Ecology GA 284DF UT WOS:000085314900001 ER PT J AU Bennett, DH McKone, TE Kastenberg, WE AF Bennett, DH McKone, TE Kastenberg, WE TI Evaluating multimedia chemical persistence: Classification and regression tree analysis SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE classification tree; multimedia; persistence; characteristic time; decay rates ID ORGANIC-CHEMICALS; UNCERTAINTY; SENSITIVITY; VARIABILITY; POLLUTANTS; MODEL; RANGE; RISK; FATE AB For the thousands of chemicals continuously released into the environment, it is desirable to make prospective assessments of those likely to be persistent. Widely distributed persistent chemicals are impossible to remove from the environment and remediation by natural processes may take decades, which is problematic if adverse health or ecological effects are discovered after prolonged release into the environment. A tiered approach using a classification scheme and a multimedia model for determining persistence is presented. Using specific criteria for persistence, a classification tree is developed to classify a chemical as "persistent" or "nonpersistent" based on the chemical properties. In this approach, the classification is derived from the results of a standardized unit world multimedia model. Thus, the classifications are more robust for multimedia pollutants than classifications using a single medium half-life. The method can be readily implemented and provides insight without requiring extensive and often unavailable data. This method can be used to classify chemicals when only a few properties are known and can be used to direct further data collection. Case studies are presented to demonstrate the advantages of the approach. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. Univ Calif Berkeley, Sch Publ Hlth, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Nucl Engn, Berkeley, CA 94720 USA. RP McKone, TE (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. NR 22 TC 8 Z9 8 U1 1 U2 6 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 APR PY 2000 VL 19 IS 4 BP 810 EP 819 DI 10.1897/1551-5028(2000)019<0810:EMCPCA>2.3.CO;2 PN 1 PG 10 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 300BF UT WOS:000086232400005 ER PT J AU Hopkins, WA Congdon, J Ray, JK AF Hopkins, WA Congdon, J Ray, JK TI Incidence and impact of axial malformations in larval bullfrogs (Rana catesbeiana) developing in sites polluted by a coal-burning power plant SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE coal combustion wastes; amphibians; selenium; malformations; behavior ID COMBUSTION WASTE; BUFO-TERRESTRIS; SOUTHERN TOADS; TOXICITY; DEFORMITIES; FISH; AMPHIBIANS; SELENIUM AB Amphibian malformations have recently received much attention from the scientific community, but Few studies have provided evidence linking environmental pollution to larval amphibian malformations in the field. We document an increased incidence of axial malformations in bullfrog larvae (Rana catesbeiana) inhabiting tao sites contaminated with coal combustion wastes. In the polluted sites, 18 and 37% of larvae exhibited lateral curvatures of the spine, whereas zero and 4% of larvae from two reference sites had similar malformations. Larvae from the most heavily polluted site had significantly higher tissue concentrations of potentially toxic trace elements, including As, Cd, Se, Cu, Cr, and V, compared with conspecifies from the reference sites. In addition, malformed larvae from the most contaminated site had decreased swimming speeds compared with those of normal larvae from the same site. We hypothesize that the complex mixture of contaminants produced by coal combustion is responsible for the high incidence of malformations and associated effects on swimming performance. C1 Savannah River Ecol Lab, Aiken, SC 29802 USA. NW State Univ, Louisiana Scholars Coll, Natchitoches, LA 71497 USA. RP Hopkins, WA (reprint author), Savannah River Ecol Lab, Drawer E, Aiken, SC 29802 USA. RI Schneider, Larissa/C-9863-2012 NR 34 TC 92 Z9 94 U1 2 U2 21 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 APR PY 2000 VL 19 IS 4 BP 862 EP 868 DI 10.1897/1551-5028(2000)019<0862:IAIOAM>2.3.CO;2 PN 1 PG 7 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 300BF UT WOS:000086232400012 ER PT J AU Genter, RB Lehman, RM AF Genter, RB Lehman, RM TI Metal toxicity inferred from algal population density, heterotrophic substrate use, and fatty acid profile in a small stream SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE algae; bacteria; metals; fatty acids; carbon source use ID MICROBIAL COMMUNITIES; ARTIFICIAL STREAMS; HEAVY-METALS; PERIPHYTON; POLLUTION; COPPER; PHYTOPLANKTON; PATTERNS; ARSENATE; ALUMINUM AB The purpose of this study was to examine relations between metal concentrations in periphyton and the abundance of algal species, heterotrophic use of 95 carbon sources, and phospholipid fatty acids (PLFA) of the periphyton in a small stream spanning a mine in Lemhi County, Idaho, USA. Two upstream, two mine, and two downstream sites were examined. Elevated concentrations of As and Cu at the mine sites were associated with communities that were depleted of diatoms and filamentous blue-green algae and characterized by a low-diversity community dominated by a single blue-green alga. and patchy populations of the diatom Achnanthidium minutissimum and a filamentous green alga. Carbon source use and PLFA profiles provided a rapid assessment of stream conditions that were consistent with algal taxonomy and with our hypotheses constructed from previous reports on periphyton responses to metal stress. C1 Johnson State Coll, Johnson, VT 05656 USA. Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Genter, RB (reprint author), Johnson State Coll, Johnson, VT 05656 USA. OI Lehman, Michael/0000-0002-3391-3178 NR 49 TC 28 Z9 31 U1 3 U2 17 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 APR PY 2000 VL 19 IS 4 BP 869 EP 878 DI 10.1897/1551-5028(2000)019<0869:MTIFAP>2.3.CO;2 PN 1 PG 10 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 300BF UT WOS:000086232400013 ER PT J AU Bender, M Rutz, K Reinhard, PG Maruhn, JA AF Bender, M Rutz, K Reinhard, PG Maruhn, JA TI Consequences of the center-of-mass correction in nuclear mean-field models SO EUROPEAN PHYSICAL JOURNAL A LA English DT Article ID D-1 EFFECTIVE INTERACTION; GROUND-STATE PROPERTIES; EFFECTIVE FORCES; SURFACE INCOMPRESSIBILITY; SKYRME PARAMETRIZATION; SHELL STRUCTURE; MATTER; DENSITIES; SUBNUCLEAR AB We study the influence of the scheme for the correction for spurious center-of-mass motion on the fit of effective interactions for self-consistent nuclear mean-field calculations. We find that interactions with very simple center-of-mass correction have significantly larger surface coefficients than interactions for which the center-of-mass correction was calculated for the actual many-body state during the fit. The reason for that is that the effective interaction has to counteract the wrong trends with nucleon number of all simplified schemes for center-of-mass correction which puts a wrong trend with mass number into the effective interaction itself. The effect becomes clearly visible when looking at the deformation energy of largely deformed systems, e.g. superdeformed states or fission barriers of heavy nuclei. C1 Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC 27516 USA. Univ Frankfurt, Inst Theoret Phys, D-60325 Frankfurt, Germany. Univ Erlangen Nurnberg, Inst Theoret Phys 2, D-91058 Erlangen, Germany. Oak Ridge Natl Lab, Joint Inst Heavy Ion Res, Oak Ridge, TN 37831 USA. RP Bender, M (reprint author), Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. RI Bender, Michael/B-9004-2009 NR 61 TC 93 Z9 99 U1 0 U2 4 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 APR PY 2000 VL 7 IS 4 BP 467 EP 478 DI 10.1007/PL00013645 PG 12 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 328YZ UT WOS:000087880500004 ER PT J AU Dzero, MO Gor'kov, LP Kresin, VZ AF Dzero, MO Gor'kov, LP Kresin, VZ TI Peculiarities in low temperature properties of doped manganites A(1-x)B(x)MnO(3) SO EUROPEAN PHYSICAL JOURNAL B LA English DT Article ID DOUBLE-EXCHANGE FERROMAGNET; METAL-INSULATOR-TRANSITION; COLOSSAL MAGNETORESISTANCE; MAGNETIC-FIELD; OPTICAL-CONDUCTIVITY; ELECTRONIC-STRUCTURE; ORBITAL DEGREES; LA1-XSRXMNO3; SPIN; CHARGE AB The phase diagram and low temperature properties of the doped manganites A(1-x)B(x)MnO(3) are discussed for the concentrations x less than or equal to 0.4. The transition from insulating antiferromagnetic to metallic ferromagnetic state at x(cr) similar or equal to 0.16 is treated by means of percolation theory. The unifying description of insulating and metallic states is presented. The undoped manganite is a band insulator consisting of ferromagnetic layers, which are coupled antiferromagnetically along the c direction with a low Neel temperature. The metallic phase can be described by the two-band Fermi liquid picture. The behavior of conductivity, spin wave excitations, etc. is analyzed and the comparison with experimental data is carried out. C1 Florida State Univ, Natl High Magnet Field Lab, Tallahassee, FL 32310 USA. Russian Acad Sci, LD Landau Theoret Phys Inst, Moscow 117334, Russia. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Dzero, MO (reprint author), Florida State Univ, Natl High Magnet Field Lab, Tallahassee, FL 32310 USA. NR 57 TC 26 Z9 26 U1 0 U2 0 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 APR PY 2000 VL 14 IS 3 BP 459 EP 471 DI 10.1007/s100510051054 PG 13 WC Physics, Condensed Matter SC Physics GA 305WE UT WOS:000086562900009 ER PT J AU Menes, R Gronbech-Jensen, N Pincus, PA AF Menes, R Gronbech-Jensen, N Pincus, PA TI Interactions between charged rods near salty surfaces SO EUROPEAN PHYSICAL JOURNAL E LA English DT Article ID GENE-TRANSFER; DNA; PROSPECTS; COMPLEXES; MEMBRANES; MIXTURES; THERAPY AB Using both theoretical modeling and computer simulations we study a model system for DNA interactions in the vicinity of charged membranes. We focus on the polarization of the mobile charges in the membranes due to the nearby charged rods (DNA) and the resulting screening of their fields and inter-rod interactions.We find, both within a Debye-Huckel model and in Brownian dynamics simulations, that the confinement of the mobile charges to the surface leads to a qualitative reduction in their ability to screen the charged rods to the degree that the fields and resulting interactions are not finite-ranged as in systems including a bulk salt concentration, but rather decay algebraically and the screening effect is more like an effective increase in the multipole moment of the charged rod. C1 Univ Calif Santa Barbara, Mat Res Lab, Santa Barbara, CA 93106 USA. Univ Calif Davis, Dept Appl Sci, Davis, CA 95616 USA. Lawrence Berkeley Natl Lab, NERSC, Berkeley, CA 94720 USA. RP Menes, R (reprint author), Univ Calif Santa Barbara, Mat Res Lab, Santa Barbara, CA 93106 USA. NR 20 TC 7 Z9 7 U1 0 U2 0 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1292-8941 J9 EUR PHYS J E JI Eur. Phys. J. E PD APR PY 2000 VL 1 IS 4 BP 345 EP 349 DI 10.1007/s101890050035 PG 5 WC Chemistry, Physical; Materials Science, Multidisciplinary; Physics, Applied; Polymer Science SC Chemistry; Materials Science; Physics; Polymer Science GA 390LT UT WOS:000166297100008 ER PT J AU Franceschetti, A Zunger, A AF Franceschetti, A Zunger, A TI Hund's rule, spin blockade, and the Aufbau principle in strongly confined semiconductor quantum dots SO EUROPHYSICS LETTERS LA English DT Article ID ELECTRON-ELECTRON INTERACTION; PSEUDOPOTENTIALS; SPECTROSCOPY; TRANSPORT; ENERGIES; COULOMB AB The ground-state configuration of a system of N electrons or holes (N = 1 ... 8) in strongly confined InAs, InP, and Si quantum dots (diameter similar to 30 Angstrom) is calculated using pseudopotential single-particle energies and wave functions as input to the many-body expansion of the total energy. The validity of generally accepted "rules of level occupation" (Hund's rule, Aufbau principle, and single spin-flip rule) is examined. We find that while Hund's rule is generally obeyed, deviations from the Aufbau principle are common when single-particle energy levels are separated by a few meV. We also find a few instances where the single spin-flip rule is violated, leading to "spin blockade" in linear conductance. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Franceschetti, A (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Zunger, Alex/A-6733-2013 NR 19 TC 18 Z9 18 U1 0 U2 2 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0295-5075 J9 EUROPHYS LETT JI Europhys. Lett. PD APR PY 2000 VL 50 IS 2 BP 243 EP 249 DI 10.1209/epl/i2000-00261-y PG 7 WC Physics, Multidisciplinary SC Physics GA 307GE UT WOS:000086644400017 ER PT J AU Terry, A Bucciarelli, G Bernardi, G AF Terry, A Bucciarelli, G Bernardi, G TI Restricted gene flow and incipient speciation in disjunct Pacific Ocean and Sea of Cortez populations of a reef fish species, Girella nigricans SO EVOLUTION LA English DT Article DE biogeography; Girella; mitochondrial DNA; population structure ID MITOCHONDRIAL CONTROL REGION; DNA-SEQUENCE VARIATION; BIOGEOGRAPHIC HISTORY; STURGEON ACIPENSER; MARINE SPECIATION; XIPHIAS-GLADIUS; BAJA-CALIFORNIA; CONSERVATION; DIVERGENCE; TELEOSTEI AB Population disjunctions have been proposed to play an important role in speciation processes. In this study, we have examined the possible role of the Pacific Ocean-Sea of Cortez disjunction as a contributing factor to cryptic speciation in a reef fish, the opaleye, Girella nigricans. Mitochondrial control region (D-loop) sequences (380 bp) of 117 individuals completely separated opaleye populations from the Pacific Ocean and the Sea of Cortez. Although opaleye exhibit pelagic larval stages that remain in the water column for several months, gene flow between the Pacific Ocean and the Sea of Cortez was found to be extremely limited (F-ST = 0.84, Nm = 0.10). Whereas limited gene flow and reciprocal monophyly suggest that the observed physical and genetic disjunction are potentially contributing to the incipient speciation of Pacific and Sea of Cortez opaleye, moderate levels of D-loop sequence divergence (3.3%) and the absence of fixed allozyme markers challenge this idea. Pacific Coast populations also exhibited restricted gene flow levels (F-ST = 0.25, Nm = 1.49) across Punta Eugenia, a recognized oceanographic boundary along the Baja California coast. Thus, opaleye individuals grouped into three clades: one clade in the Sea of Cortez, one Pacific clade south of Punta Eugenia, and one Pacific clade north of Punta Eugenia. Future work in this region will determine if our results can be generalized to other disjunct populations. C1 Univ Calif Santa Cruz, Dept Biol, Santa Cruz, CA 95064 USA. RP Terry, A (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RI Bernardi, Giacomo/F-6346-2011; OI Bernardi, Giacomo/0000-0002-8249-4678; Terry, Astrid/0000-0002-5234-1224 NR 55 TC 54 Z9 54 U1 0 U2 6 PU SOC STUDY EVOLUTION PI LAWRENCE PA 810 E 10TH STREET, LAWRENCE, KS 66044 USA SN 0014-3820 J9 EVOLUTION JI Evolution PD APR PY 2000 VL 54 IS 2 BP 652 EP 659 PG 8 WC Ecology; Evolutionary Biology; Genetics & Heredity SC Environmental Sciences & Ecology; Evolutionary Biology; Genetics & Heredity GA 311LV UT WOS:000086886500029 PM 10937240 ER PT J AU Gelb, JM Rosen, SP AF Gelb, JM Rosen, SP TI Another look at Just-So solar neutrino oscillations SO FOUNDATIONS OF PHYSICS LA English DT Article ID VACUUM OSCILLATION; SPECTRUM AB We take another look at "Just-So" solar neutrino oscillations, characterising them by the energy E-pi/2 at which the distance-varying angle is pi/2, instead of by the usual Delta m(2). The rising spectrum recently observed by SuperKamiokande is consistent with an E-pi/2 similar to 6-9 MeV and marginally with 48 MeV. The pp neutrinos must then be reduced to one-half the standard solar model prediction, and Be-7 neutrinos must make up a significant part of the SAGE and GALLEX gallium signal. For E pi/2 close to 9 and 48 MeV, the Be-7 neutrinos will also show a large seasonal variation, emphasizing the importance of direct measurements of the Be-7 neutrinos. C1 Univ Texas, Dept Phys, Arlington, TX 76019 USA. US Dept Energy, Germantown, MD 20874 USA. RP Gelb, JM (reprint author), Univ Texas, Dept Phys, POB 19059, Arlington, TX 76019 USA. NR 32 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 0015-9018 J9 FOUND PHYS JI Found. Phys. PD APR PY 2000 VL 30 IS 4 BP 599 EP 606 DI 10.1023/A:1003625029844 PG 8 WC Physics, Multidisciplinary SC Physics GA 343YM UT WOS:000088730900008 ER PT J AU McNamara, AE Hill, WR AF McNamara, AE Hill, WR TI UV-B irradiance gradient affects photosynthesis and pigments but not food quality of periphyton SO FRESHWATER BIOLOGY LA English DT Article DE algae; UV-B; food quality; periphyton; photosynthesis ID NATURAL ULTRAVIOLET-RADIATION; INDUCED PYRIMIDINE DIMERS; ANTARCTIC CYANOBACTERIA; PHYTOPLANKTON; STREAM; RESPONSES; GROWTH; PHOTOINHIBITION; COMMUNITY; NUTRIENT AB 1. This laboratory study examined the effect of a gradient of UV-B radiation (280-320 nm) on photosynthesis and food quality of periphyton, the trophic base of many freshwater benthic communities. Four irradiances of UV-B (0, 0.6, 1.2, and 2.3 W m(--2)) were delivered by UV-B lamps (313 nm peak irradiance) over a 13-day period in the first experiment and over a 4-h period in the second experiment. These irradiances were roughly equivalent to 0, 1, 2, and 4 times the ambient biologically effective (DNA) midsummer, midday UV-B irradiance in Tennessee. 2. Rates of photosynthesis and photosynthetic pigments were significantly reduced by irradiances greater than ambient during the 13-day experiment, suggesting that food supply rates to grazers would be depressed by increases in current UV-B levels. Effects on community structure were minor, but mean diatom cell size decreased at higher UV-B irradiances. 3. Irradiated periphyton was fed in surplus to juvenile snails (Physella gyrina) in the first experiment as a bioassay for food quality. Snail growth was the same on all four diets, suggesting that UV-B did not affect food quality. Nitrogen and phosphorus content of the periphyton were not affected by UV-B, either. 4. Photosynthesis by low-biomass periphyton in the second experiment was significantly depressed by irradiances above ambient after only 4 h. Photosynthesis by the high biomass periphyton was not significantly affected by UV-B, suggesting that self-shading reduced UV-B effects. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Univ Louisville, Dept Biol, Louisville, KY 40292 USA. RP Hill, WR (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. NR 58 TC 42 Z9 44 U1 2 U2 10 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0046-5070 J9 FRESHWATER BIOL JI Freshw. Biol. PD APR PY 2000 VL 43 IS 4 BP 649 EP 662 DI 10.1046/j.1365-2427.2000.00537.x PG 14 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 301VJ UT WOS:000086330700010 ER PT J AU Lin, XF Song, YY Soloway, RD Xu, YZ Zhang, X Tian, W Xie, DT Sun, Y Zhang, TL Zhou, XS Ferraro, JR Wu, JG AF Lin, XF Song, YY Soloway, RD Xu, YZ Zhang, X Tian, W Xie, DT Sun, Y Zhang, TL Zhou, XS Ferraro, JR Wu, JG TI Fourier transforming Raman spectra can separate most normal and malignant tissue. SO GASTROENTEROLOGY LA English DT Meeting Abstract C1 Peking Univ, Beijing 100871, Peoples R China. Univ Texas, Med Branch, Galveston, TX 77550 USA. Argonne Natl Lab, Chicago, IL USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU W B SAUNDERS CO-ELSEVIER INC PI PHILADELPHIA PA 1600 JOHN F KENNEDY BOULEVARD, STE 1800, PHILADELPHIA, PA 19103-2899 USA SN 0016-5085 EI 1528-0012 J9 GASTROENTEROLOGY JI Gastroenterology PD APR PY 2000 VL 118 IS 4 SU 2 MA 6351 BP A1398 EP A1398 PN 2 PG 1 WC Gastroenterology & Hepatology SC Gastroenterology & Hepatology GA 309RY UT WOS:000086784101424 ER PT J AU Schwartz, S Zhang, Z Frazer, KA Smit, A Riemer, C Bouck, J Gibbs, R Hardison, R Miller, W AF Schwartz, S Zhang, Z Frazer, KA Smit, A Riemer, C Bouck, J Gibbs, R Hardison, R Miller, W TI PipMaker - A Web server for aligning two genomic DNA sequences SO GENOME RESEARCH LA English DT Article ID ESCHERICHIA-COLI K-12; SALMONELLA-TYPHIMURIUM; GENE; EVOLUTION; REGION; FLAVOHEMOGLOBIN; IDENTIFICATION; GENERATION; DATABASE; PROGRAMS AB PipMaker (http://bio.cse.psu.edu) is a World-Wide Web site for comparing two long DNA sequences to identify conserved segments and for producing informative, high-resolution displays of the resulting alignments. One display is a percent identity plot (pip), which shows both the position in one sequence and the degree of similarity for each aligning segment between the two sequences in a compact and easily understandable form. Positions along the horizontal axis can be labeled with features such as exons of genes and repetitive elements, and colors can be used to clarify and enhance the display. The web site also provides a plot of the Locations of those segments in both species (similar to a dot plot). PipMaker is appropriate for comparing genomic sequences from any two related species, although the types of information that can be inferred (e.g., protein-coding regions and cis-regulatory elements) depend on the level of conservation and the time and divergence rate since the separation of the species. Gene regulatory elements are often detectable as similar, noncoding sequences in species that diverged as much as 100-300 million years ago, such as humans and mice, Caenorhabditis elegans and C. briggsae, or Escherichia coli and Salmonella spp. PipMaker supports analysis of unfinished or "working draft" sequences by permitting one of the two sequences to be in unoriented and unordered contigs. C1 Penn State Univ, Dept Comp Sci & Engn, University Pk, PA 16802 USA. Penn State Univ, Dept Biochem & Mol Biol, University Pk, PA 16802 USA. Penn State Univ, Ctr Gene Regulat, University Pk, PA 16802 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Genome Sci Dept, Berkeley, CA 94720 USA. Axys Pharmaceut, La Jolla, CA 92037 USA. Baylor Coll Med, Dept Mol & Human Genet, Houston, TX 77030 USA. RP Miller, W (reprint author), Penn State Univ, Dept Comp Sci & Engn, University Pk, PA 16802 USA. RI Hardison, Ross/G-1142-2010 OI Hardison, Ross/0000-0003-4084-7516 FU NIDDK NIH HHS [R01DK27635]; NLM NIH HHS [R01LM05110, R01LM05773] NR 39 TC 867 Z9 887 U1 0 U2 13 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 APR PY 2000 VL 10 IS 4 BP 577 EP 586 DI 10.1101/gr.10.4.577 PG 10 WC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity GA 309AD UT WOS:000086744300023 PM 10779500 ER PT J AU Wang, Z Ainsworth, CC Friedrich, DM Gassman, PL Joly, AG AF Wang, Z Ainsworth, CC Friedrich, DM Gassman, PL Joly, AG TI Kinetics and mechanism of surface reaction of salicylate on alumina in colloidal aqueous suspension SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID OXIDE-WATER INTERFACE; ORGANIC-ACIDS; ADSORPTION DESORPTION; PROTON-TRANSFER; COMPLEXES; EXCHANGE; DISSOLUTION; PHOSPHATE; GOETHITE; IONS AB The reaction kinetics of salicylate with Al(III) in aqueous solution and at the colloidal aluminawater interface was studied by stopped-flow laser fluorescence spectroscopy. Temporal evolution of the fluorescence spectra suggests that formation of a carboxylate monodentate complex was the reaction intermediate that occurs transiently at the beginning of the reaction in aqueous salicylate-Al(III) solution. However, by lowering the pH to 2.0, the formation of such an intermediate can be directly observed as it is the only species formed. The reaction of salicylate with aqueous Al3+ is completed within 10 min at pH 3.3 but is significantly slower at pH 2.0. At both pH the aqueous reaction follows a single pseudo-first order rate law. In alumina suspension the reaction was initially fast but slowed down after similar to 30 s. Completion of the reaction took up to 12 h, depending on pH and ionic strength. The formation of a carboxylate monodentate surface complex as a transient species is clearly observed in alumina suspensions at near neutral pH. The initial rapid reaction (<30 s), accounting for similar to 70% of the total reaction, can be best described by the Elovich rate equation and the slower reaction, accounting for similar to 30% of the total reaction, obeys pseudo-first order kinetics. These results are consistent with a sorption reaction mechanism that is controlled by the leaving group lability at the surface sites (Al-OH2+ and Al-OH). The pseudo-first order rate constant varies little with initial salicylate concentration, ionic strength, or pH > 4, suggesting that the slow reaction pathway involves ligand substitution reactions between salicylate and the hydroxyl groups for which the Al-O binding and activation energy are affected by site heterogeneity or site density to a lesser degree than Al-OH2+ sites. Copyright (C) 2000 Elsevier Science Ltd. C1 Pacific NW Natl Lab, Environm & Mol Sci Lab, Richland, WA 99352 USA. Pacific NW Natl Lab, Interfacial Geochem Grp, Richland, WA 99352 USA. RP Wang, Z (reprint author), Pacific NW Natl Lab, Environm & Mol Sci Lab, Richland, WA 99352 USA. RI Wang, Zheming/E-8244-2010 OI Wang, Zheming/0000-0002-1986-4357 NR 47 TC 16 Z9 18 U1 0 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD APR PY 2000 VL 64 IS 7 BP 1159 EP 1172 DI 10.1016/S0016-7037(99)00360-9 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 297UM UT WOS:000086101100002 ER PT J AU Fenter, P Geissbuhler, P DiMasi, E Srajer, G Sorensen, LB Sturchio, NC AF Fenter, P Geissbuhler, P DiMasi, E Srajer, G Sorensen, LB Sturchio, NC TI Surface speciation of calcite observed in situ by high-resolution X-ray reflectivity SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID SOLID-SOLUTION FORMATION; FORCE MICROSCOPY; WATER INTERFACE; GROWTH; DISSOLUTION; ADSORPTION; KINETICS; RHODOCHROSITE; COMPLEXATION; DIFFRACTION AB High-resolution, in situ X-ray reflectivity measurements were made of the calcite (104)-water interface in calcite-saturated aqueous solutions at pH values ranging from 6.8 to 12.1 and low P-CO2. The X-ray reflectivity data, taken over a momentum transfer range of 6 Angstrom(-1), indicate that the calcite surface does not vary significantly over this range of experimental conditions. From an analysis of the data at pH 8.3, the best-fit reflectivity model requires the presence of 1.0 +/- 0.4 monolayer of a hydroxyl species (OH or OH2) at 2.50 +/- 0.12 Angstrom above the surface Ca ions and involves rotations of the surface carbonate groups toward the (104) plane. The X-ray reflectivity data for pH 6.8 and 12.1 can be explained without invoking changes other than protonation reactions in the surface speciation of terrace areas. This is consistent with scanning force microscopy studies of calcite growth and dissolution near equilibrium, which show that attachment and detachment of Ca and CO3 ions occurs primarily at step-edge kink sites. These results demonstrate how high-resolution X-ray reflectivity can be used for direct, in situ measurement of mineral surface structure, to provide strong constraints on chemical speciation and reactivity at the mineral-fluid interface. Copyright (C) 2000 Elsevier Science Ltd. C1 Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. Univ Washington, Dept Phys, Seattle, WA 98195 USA. Brookhaven Natl Lab, Div Phys, Upton, NY 11973 USA. Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RP Fenter, P (reprint author), Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. NR 45 TC 173 Z9 173 U1 5 U2 44 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD APR PY 2000 VL 64 IS 7 BP 1221 EP 1228 DI 10.1016/S0016-7037(99)00403-2 PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 297UM UT WOS:000086101100006 ER PT J AU Zachara, JM Smith, SC Fredrickson, JK AF Zachara, JM Smith, SC Fredrickson, JK TI The effect of biogenic Fe(II) on the stability and sorption of Co(II)EDTA(2-) to goethite and subsurface sediment SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID METAL-EDTA COMPLEXES; CO(II/III)EDTA REACTIVE TRANSPORT; POLLUTION PLUME VEJEN; MICROBIAL REDUCTION; MANGANESE OXIDE; REDOX ZONES; ADSORPTION; IRON; MIGRATION; DENMARK AB Laboratory experiments were conducted with suspensions of goethite (alpha-FeOOH) and a subsurface sediment to assess the influence of bacterial iron reduction on the fate of Co(II)EDTA(2-), a representative metal-ligand complex of intermediate stability (log K-Co(II)EDTA = 17.97). The goethite was synthetic (ca. 55 m(2)/g) and the sediment was a Pleistocene age, Fe(III) oxide-containing material from the Atlantic coastal plain (Milford). Shewanella alga strain BrY, a dissimilatory iron reducing bacterium (DIRB), was used to promote Fe(III) oxide reduction. Sorption isotherms and pH adsorption edges were measured for Co2+, Fe2+, Co(II)EDTA(2-), and Fe(II)EDTA(2-) on the two sorbents in 0.001 mol/L Ca(ClO4)(2) to aid in experiment interpretation. Anoxic suspensions of the sorbents in PIPES buffer at pH 6.5-7.0 were spiked with Co(II)EDTA(2-) (10(-5) mol/L, Co-60 and (14)EDTA labeled), inoculated with BrY (1-6 x 10(8) organisms/mL), and the headspace filled with a N-2/H-2 gas mix. The experiments were conducted under non-growth conditions. The medium did not contain PO43- (with one exception), trace elements, or vitamins. The tubes were incubated under anoxic conditions at 25 degrees C for time periods in excess of 100 d. Replicate tubes were sacrificed and analyzed at desired time periods for pH, Fe(II)(TOT), Fe-(aq),(2+) Co-60, and (14)EDTA. Abiotic analogue experiments were conducted where Fe-(aq)(2+) was added in increasing concentration to Co(II)EDTA(2-)/mineral suspensions to simulate the influence of bacterial Fe(II) evolution. The DIRE generated Fe(II) from both goethite and the Milford sediment that was strongly sorbed by mineral surfaces. Aqueous Fe2+ increased during the experiment as surfaces became saturated; Fe-(aq)(2+) induced the dissociation of Co(II)EDTA(2-) into a mixture of Co2+ Co(II)EDTA(2-), and Fe(II)EDTA(2-) (log K-Fe(II)EDTA = 15.98). The extent of dissociation of Co(II)EDTA(2-) was greater in the subsurface sediment because it sorbed Fe(II) less strongly than did goethite. The post dissociation sorption behavior of Co2+ was dependent on pH and the intrinsic sorptivity of the solid phases. Dissociation generally lead to an increase in the sorption (e.g., K-d) of Co2+ relative to EDTA(4-) (form unspecified). Sorbed biogenic Fe(II) competed with free Co-(aq)(2+) and reduced its sorption relative to unreduced material. It is concluded that cationic radionuclides such as Co-60 or Pu-239/240, Which may be mobilized from disposed wastes by complexation with EDTA(4-), may become immobilized in groundwater zones where dissimilatory bacterial iron reduction is operative. Copyright (C) 2000 Elsevier Science Ltd. C1 Pacific NW Lab, Richland, WA 99352 USA. RP Zachara, JM (reprint author), Pacific NW Lab, POB 999, Richland, WA 99352 USA. EM john.zachara@pnl.gov NR 45 TC 28 Z9 28 U1 2 U2 8 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 APR PY 2000 VL 64 IS 8 BP 1345 EP 1362 DI 10.1016/S0016-7037(99)00427-5 PG 18 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 303UE UT WOS:000086442600002 ER PT J AU Maurice, PA Lee, YJ Hersman, LE AF Maurice, PA Lee, YJ Hersman, LE TI Dissolution of Al-substituted goethites by an aerobic Pseudomonas mendocina var. bacteria SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID ATOMIC-FORCE MICROSCOPY; IRON-OXIDES; HYDROUS FE(III)-OXIDES; DISSIMILATORY FE(III); REDUCTIVE DISSOLUTION; ALUMINOUS GOETHITES; MICROBIAL REDUCTION; ORGANIC-ACIDS; SURFACE; HEMATITE AB Goethite particles in soil environments often contain Al3+ substituted for Fe3+ in octahedrally coordinated sites. Al substitution has been shown to alter mineral stability and abiotic dissolution rates. This study focused on the effects of Al substitution (to 8.8 mol%) on synthetic goethite dissolution by an aerobic Pseudomonas mendocina var. bacteria. In contrast to dissimilatory iron reducing bacteria (DIRB), this bacteria is not capable of using Fe as a terminal electron acceptor for oxidative phosphorylation, and hence only requires mu M concentrations of Fe for metabolism. Pure and substituted goethites were reacted with microorganisms in Fe-limited growth media wherein the only source of Fe was the solid phase, so that microbial populations could only grow by obtaining Fe through mineral dissolution. Because at least some Fe was taken up by the bacteria, we could not measure Fe release rates directly from dissolved Fe concentrations. Rather, we relied upon microbial growth measurements as indirect indicators of mineral dissolution. Increasing Al substitution resulted in particles with progressively decreasing mean particle length and aspect ratios, as well as fewer domains, as measured by atomic-force microscopy (AFM); but with increasing structural order as determined by XRD line widths. Experiments conducted in the dark at 22 degrees C, exposed to the atmosphere, showed that maximum microbial population did not correlate with particle specific surface area, which is in contrast with previous studies using DIRE. Maximum microbial population increased a small amount with increasing Al content of the goethites, in contrast with several previous investigations of abiotic dissolution. Because dense biofilms formed, we were unable to use AFM to observe mineral dissolution features. AFM imaging suggested that more highly substituted goethites formed denser aggregates, and previous investigations have shown that aggregate structure is important for microbial attachment, which is prerequisite for dissolution. Hence, effects of Al substitution on aggregate structure is a focus of ongoing research. Copyright (C) 2000 Elsevier Science Ltd. C1 Univ Notre Dame, Dept Civil Engn & Geol Sci, Notre Dame, IN 46556 USA. Kent State Univ, Dept Geol, Kent, OH 44242 USA. Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. RP Maurice, PA (reprint author), Univ Notre Dame, Dept Civil Engn & Geol Sci, Notre Dame, IN 46556 USA. EM pmaurice@nd.edu NR 53 TC 45 Z9 46 U1 5 U2 11 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 APR PY 2000 VL 64 IS 8 BP 1363 EP 1374 DI 10.1016/S0016-7037(99)00404-4 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 303UE UT WOS:000086442600003 ER PT J AU Brown, SL Bierman, PR Lini, A Southon, J AF Brown, SL Bierman, PR Lini, A Southon, J TI 10 000 yr record of extreme hydrologic events SO GEOLOGY LA English DT Article DE hydrology; storms; lake cores; floods ID YELLOWSTONE-NATIONAL-PARK; CHARCOAL ANALYSIS; LAKE-SEDIMENTS; FIRE HISTORY; HOLOCENE; VEGETATION; MOUNTAINS; CLIMATE; USA AB Well-dated lacustrine sediments provide a hydrologic record indicating that the frequency and magnitude of runoff events, and by inference, storms, have varied over the past 10 k.y. in northern New England, We used five sediment cores and radiocarbon dating to develop a chronology of Holocene hydrologic events for the Ritterbush Pond basin, northern Vermont. Chemical and physical analyses allow us to identify 52 distinct layers of predominately inorganic sediment that represent terrestrially derived material delivered to the pond by runoff events. The thickness of some layers suggests hydrologic events at least equal in size to, and probably much larger than, any storm or flood recorded during nearly 300 yr of written regional history. Layer thickness and frequency and, by analogy, storm size and recurrence, change through the Holocene. The Largest events occurred 2620, 6840, and 9440 calibrated C-14 years before present (cal C-14 yr B.P.). The most frequent hydrologic events occurred in three periods: 1750 to 2620, 6330 to 6840 and >8600 cat yr B.P. The recurrence interval of layer deposition during stormy periods averages 130+/-100 cat yr, whereas the recurrence interval during less stormy periods is longer, 270+/-170 cal yr. The Ritterbush Pond event record illustrates the potential of inorganic lacustrine sediment to serve as a proxy record for estimating paleoflood frequency and deciphering climate change. C1 Univ Vermont, Dept Geol, Burlington, VT 05405 USA. Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94551 USA. RP Brown, SL (reprint author), Terrasearch Inc, 6840 Via Del Oro,Suite 110, San Jose, CA 95119 USA. OI Lini, Andrea/0000-0002-2920-570X NR 32 TC 54 Z9 60 U1 5 U2 33 PU GEOLOGICAL SOC AMERICA, INC PI BOULDER PA PO BOX 9140, BOULDER, CO 80301-9140 USA SN 0091-7613 J9 GEOLOGY JI Geology PD APR PY 2000 VL 28 IS 4 BP 335 EP 338 DI 10.1130/0091-7613(2000)28<335:YROEHE>2.0.CO;2 PG 4 WC Geology SC Geology GA 300AC UT WOS:000086229800012 ER PT J AU Cullen, HM deMenocal, PB Hemming, S Hemming, G Brown, FH Guilderson, T Sirocko, F AF Cullen, HM deMenocal, PB Hemming, S Hemming, G Brown, FH Guilderson, T Sirocko, F TI Climate change and the collapse of the Akkadian empire: Evidence from the deep sea SO GEOLOGY LA English DT Article DE Holocene climate; Middle East; civilization collapse ID NORTH-ATLANTIC; ARABIAN GULF; SEDIMENTS; HOLOCENE; CIVILIZATION; ISOTOPES; GENESIS; KUWAIT; EVENTS; ND AB The Akkadian empire ruled Mesopotamia from the headwaters of the Tigris-Euphrates Rivers to the Persian Gulf during the late third millennium B.C. Archeological evidence has shown that this highly developed civilization collapsed abruptly near 4170 +/- 150 calendar yr B.P., perhaps related to a shift to more arid conditions. Detailed paleoclimate records to test this assertion from Mesopotamia are rare, but changes in regional aridity are preserved in adjacent ocean basins. We document Holocene changes in regional aridity using mineralogic and geochemical analyses of a marine sediment core from the Gulf of Oman, which is directly downwind of Mesopotamian dust source areas and archeological sites. Our results document a very abrupt increase in eolian dust and Mesopotamian aridity, accelerator mass spectrometer radiocarbon dated to 4025 +/- 125 calendar yr B.P., which persisted for similar to 300 yr. Radiogenic (Nd and Sr) isotope analyses confirm that the observed increase in mineral dust was derived from Mesopotamian source areas. Geochemical correlation of volcanic ash shards between the archeological site and marine sediment record establishes a direct temporal link between Mesopotamian aridification and social collapse, implicating a sudden shift to more arid conditions as a key factor contributing to the collapse of the Akkadian empire. C1 Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. Univ Utah, Park City, UT 84112 USA. Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Johannes Gutenberg Univ Mainz, Inst Geowissensch, D-55099 Mainz, Germany. RP Cullen, HM (reprint author), Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. RI demenocal, peter/B-1386-2013 OI demenocal, peter/0000-0002-7191-717X NR 28 TC 279 Z9 306 U1 9 U2 115 PU GEOLOGICAL SOC AMER, INC PI BOULDER PA PO BOX 9140, BOULDER, CO 80301-9140 USA SN 0091-7613 J9 GEOLOGY JI Geology PD APR PY 2000 VL 28 IS 4 BP 379 EP 382 DI 10.1130/0091-7613(2000)28<379:CCATCO>2.0.CO;2 PG 4 WC Geology SC Geology GA 300AC UT WOS:000086229800023 ER PT J AU Wright, DL McGraw, R Benkovitz, CM Schwartz, SE AF Wright, DL McGraw, R Benkovitz, CM Schwartz, SE TI Six-moment representation of multiple aerosol populations in a sub-hemispheric chemical transformation model SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PARTICLE-SIZE DISTRIBUTION; DIMENSIONAL SECTIONAL MODEL; MARINE BOUNDARY-LAYER; OPTICAL-PROPERTIES; DYNAMICS; SULFATE AB This letter describes the first application of the Quadrature Method of Moments (QMOM) [McGraw, 1997] in a 3-D chemical transformation and transport model. The QMOM simultaneously tracks an arbitrary (even) number of moments of a particle size distribution directly in space and time without the need for explicitly representing the distribution itself. The host 3-D model, the Global Chemistry Model driven by Observation-derived meteorological data (GChM-O), has been previously described [Benkovitz et al., 1994]. The present implementation evolves the six lowest-order radial moments for each of several externally-mixed aerosol populations. From these moments we report modeled geographic distributions of several aerosol properties, including a shortwave radiative forcing obtained using the Multiple Isomomental Distribution aerosol Surrogate (MIDAS) technique [Wright, 2000]. These results demonstrate the capabilities of these moment-based techniques to simultaneously represent aerosol nucleation, condensation, coagulation, dry deposition, wet removal, cloud activation, and transport processes in a large scale model, and to yield aerosol optical properties and radiative influence from the modeled aerosol. C1 Brookhaven Natl Lab, Dept Appl Sci, Environm Chem Div, Upton, NY 11973 USA. RP Wright, DL (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Environm Chem Div, Upton, NY 11973 USA. RI Schwartz, Stephen/C-2729-2008 OI Schwartz, Stephen/0000-0001-6288-310X NR 20 TC 24 Z9 24 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 1 PY 2000 VL 27 IS 7 BP 967 EP 970 DI 10.1029/1999GL010975 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 299XV UT WOS:000086224500015 ER PT J AU Lovat, LB Pickard, D Novelli, M Ripley, PM Francis, H Bigo, IJ Bown, SG AF Lovat, LB Pickard, D Novelli, M Ripley, PM Francis, H Bigo, IJ Bown, SG TI A novel 'optical biopsy' technique using elastic scattering spectroscopy for dysplasia and cancer in Barrett's oesophagus SO GUT LA English DT Meeting Abstract C1 UCL, Royal Free & Univ Coll Sch Med, Natl Med Laser Ctr, London WC1E 6BT, England. UCL, Royal Free & Univ Coll Sch Med, Dept Histopathol, London WC1E 6BT, England. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RI Lovat, Laurence/C-1986-2009; Bown, Stephen/C-5713-2009 OI Lovat, Laurence/0000-0003-4542-3915; NR 0 TC 0 Z9 0 U1 0 U2 0 PU B M J PUBLISHING GROUP PI LONDON PA BRITISH MED ASSOC HOUSE, TAVISTOCK SQUARE, LONDON WC1H 9JR, ENGLAND SN 0017-5749 J9 GUT JI Gut PD APR PY 2000 VL 46 SU 2 MA TH1 BP A75 EP A75 PG 1 WC Gastroenterology & Hepatology SC Gastroenterology & Hepatology GA 298YZ UT WOS:000086170200297 ER PT J AU Annab, LA Terry, L Cable, PL Brady, J Stampfer, MR Barrett, JC Afshari, CA AF Annab, LA Terry, L Cable, PL Brady, J Stampfer, MR Barrett, JC Afshari, CA TI Establishment and characterization of a breast cell strain containing a BRCA1 185delAG mutation SO GYNECOLOGIC ONCOLOGY LA English DT Article; Proceedings Paper CT Keystone Symposia 99 CY MAR 15-20, 1999 CL TAOS, NEW MEXICO DE BRCA1; breast cell line; breast cancer; germline mutation ID OVARIAN-CANCER FAMILIES; ASHKENAZI JEWISH WOMEN; TUMOR-SUPPRESSOR GENE; DNA-DAMAGING AGENTS; ESTROGEN-RECEPTOR; CYCLE REGULATION; EXPRESSION; CARCINOMA; LINES; P53 AB Objective. The aim of this study was to examine whether cells containing the heterozygous form of a BRCA1 185delAG mutation would exhibit abnormal growth or an altered response to DNA damage. Methods. A primary culture of human mammary epithelial cells (90P) was obtained from the nontumor breast tissue of a 35-year-old patient who had undergone a mastectomy for removal of a breast tumor. These cells were immortalized (90PE6E7) following retroviral infection with HPV-16 viral E6/E7. genes. Both the 90P cell strain and the cell line were characterized for their ability to grow in culture, form colonies in soft agar, and produce tumors in athymic nude mice compared to normal breast epithelial cells containing wild-type BRCA1. 90P cells were also analyzed for cellular response to gamma radiation and H2O2. Results. These cells were confirmed to contain a frameshift mutation, 185delAG, of the BRCA1 gene. Despite being heterozygous for wild-type BRCA1, the 220-kDa full-size BRCA1 protein was abundantly expressed. 90P and 90PE6E7 cells grew at a similar rate and were anchorage dependent. 90PE6E7 also failed to form tumors in athymic nude mice, Finally, 90P cells exhibited a survival response similar to that of normal mammary epithelial cells to radiation damage and exposure to oxidative stress. Conclusion. To our knowledge the 90P cells and the 90PE6E7 cells are the first characterized, non-tumor-derived breast epithelial cells that are heterozygous for the BRCA1 germline mutation 185delAG. Our conclusion is that these BRCA1 mutant cells appear to have growth and stress response characteristics similar to those of normal human breast cells, which is consistent with the hypothesis that loss of heterozygosity must occur to impair putative BRCA1 function. (C) 2000 Academic Press. C1 NIEHS, Mol Carcinogenesis Lab, Res Triangle Pk, NC 27709 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94704 USA. RP Annab, LA (reprint author), NIEHS, Mol Carcinogenesis Lab, POB 12233,MD2-04, Res Triangle Pk, NC 27709 USA. FU NCI NIH HHS [CA-24844] NR 49 TC 8 Z9 8 U1 1 U2 2 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0090-8258 J9 GYNECOL ONCOL JI Gynecol. Oncol. PD APR PY 2000 VL 77 IS 1 BP 121 EP 128 DI 10.1006/gyno.2000.5734 PG 8 WC Oncology; Obstetrics & Gynecology SC Oncology; Obstetrics & Gynecology GA 304NW UT WOS:000086491200019 PM 10739701 ER PT J AU Klemic, GA Shobe, J Sengupta, S AF Klemic, GA Shobe, J Sengupta, S TI Environmental dosimetry performance criteria: Pilot test of proposed ANSI Draft Standard N13.29 SO HEALTH PHYSICS LA English DT Article DE monitoring; environmental; radiation; environmental; detector; radiation; standards AB American National Standards Institute (ANSI) standards are a source of technical guidance on the application of passive radiation detectors in personnel and environmental monitoring programs. The proposed new ANSI Draft N13.29 describes performance tests for environmental dosimetry providers that are analogous to those now required in personnel dosimetry. The objective of this study was to pilot test the procedural specifications before Draft N13.29 is submitted for final balloting, The results of the performance tests are relevant to environmental surveillance programs, which may be affected if Draft N13.29 is approved. Seven environmental dosimetry providers submitted dosimeters for the pilot test, which included two phases. The first phase involved exposing dosimeters to laboratory gamma, beta, and x-ray sources at routine and accident dose levels. In the second phase, dosimeters were subjected to 90 d of simulated environmental conditions in a chamber that cycled through prescribed temperature and humidity parameters and lighting conditions. Two participants passed all categories of the laboratory test phase, and all seven passed the environmental test phase. We report here on the results of the performance tests; additional results relevant to finalizing Draft N13.29 are detailed elsewhere. C1 US DOE, Environm Measurements Lab, New York, NY 10014 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. EM klemic@eml.doe.gov NR 16 TC 1 Z9 1 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD APR PY 2000 VL 78 IS 4 BP 370 EP 376 DI 10.1097/00004032-200004000-00002 PG 7 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 294UY UT WOS:000085929800002 PM 10749521 ER PT J AU Clifford, SM Crisp, D Fisher, DA Herkenhoff, KE Smrekar, SE Thomas, PC Wynn-Williams, DD Zurek, RW Barnes, JR Bills, BG Blake, EW Calvin, WM Cameron, JM Carr, MH Christensen, PR Clark, BC Clow, GD Cutts, JA DahlJensen, D Durham, WB Fanale, FP Farmer, JD Forget, F Gotto-Azuma, K Grard, R Haberle, RM Harrison, W Harvey, R Howard, AD Ingersoll, AP James, PB Kargel, JS Kieffer, HH Larsen, J Lepper, K Malin, MC McCleese, DJ Murray, B Nye, JF Paige, DA Platt, SR Plaut, JJ Reeh, N Rice, JW Smith, DE Stoker, CR Tanaka, KL Mosley-Thompson, E Thorsteinsson, T Wood, SE Zent, A Zuber, MT Zwally, HJ AF Clifford, SM Crisp, D Fisher, DA Herkenhoff, KE Smrekar, SE Thomas, PC Wynn-Williams, DD Zurek, RW Barnes, JR Bills, BG Blake, EW Calvin, WM Cameron, JM Carr, MH Christensen, PR Clark, BC Clow, GD Cutts, JA DahlJensen, D Durham, WB Fanale, FP Farmer, JD Forget, F Gotto-Azuma, K Grard, R Haberle, RM Harrison, W Harvey, R Howard, AD Ingersoll, AP James, PB Kargel, JS Kieffer, HH Larsen, J Lepper, K Malin, MC McCleese, DJ Murray, B Nye, JF Paige, DA Platt, SR Plaut, JJ Reeh, N Rice, JW Smith, DE Stoker, CR Tanaka, KL Mosley-Thompson, E Thorsteinsson, T Wood, SE Zent, A Zuber, MT Zwally, HJ TI The state and future of Mars polar science and exploration SO ICARUS LA English DT Article; Proceedings Paper CT 1st International Conference on Mars Polar Science and Exploration CY OCT 18-22, 1998 CL ALLEN, TX SP Lunar & Planetary Inst, Natl Aeronaut & Space Administrat Geolog, Int Glaciolog Soc DE Mars, surface; Mars, atmosphere; Mars, climate; ices; exobiology ID GENERAL-CIRCULATION MODEL; THERMAL MAPPER OBSERVATIONS; ORBITER-LASER-ALTIMETER; MARTIAN NORTHERN PLAINS; GROUND ICE INTERACTIONS; LAYERED DEPOSITS; ATMOSPHERIC DYNAMICS; WATER-VAPOR; CO2 ICE; SUMMER TEMPERATURES AB As the planet's principal cold traps, the martian polar regions have accumulated extensive mantles of ice and dust that cover individual areas of similar to 10(6) km(2) and total as much as 3-4 km thick. From the scarcity of superposed craters on their surface, these layered deposits are thought to be comparatively young-preserving a record of the seasonal and climatic cycling of atmospheric CO2, H2O, and dust over the past similar to 10(5)-10(8) years. For this reason, the martian polar deposits may serve as a Rosetta Stone for understanding the geologic and climatic history of the planet-documenting variations in insolation (due to quasiperiodic oscillations in the planet's obliquity and orbital elements), volatile mass balance, atmospheric composition, dust storm activity, volcanic eruptions, large impacts, catastrophic floods, solar luminosity, supernovae, and perhaps even a record of microbial life. Beyond their scientific value, the polar regions may soon prove important for another reason-providing a valuable and accessible reservoir of water to support the long-term human exploration of Mars. In this paper we assess the current state of Mars polar research, identify the key questions that motivate the exploration of the polar regions, discuss the extent to which current missions will address these questions, and speculate about what additional capabilities and investigations may be required to address the issues that remain outstanding. (C) 2000 Academic Press. C1 Lunar & Planetary Inst, Houston, TX 77058 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Geol Survey Canada, Terrain Sci Div, Ottawa, ON K1A 0E8, Canada. US Geol Survey, Flagstaff, AZ 86001 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. British Antarctic Survey, NERC, Cambridge CB3 0ET, England. Oregon State Univ, Coll Ocean & Atmospher Sci, Corvallis, OR 97331 USA. NASA, Goddard Space Flight Ctr, Geodynam Branch, Greenbelt, MD 20771 USA. Icefield Instruments Inc, Whitehorse, YT Y1A 5H4, Canada. US Geol Survey, Menlo Pk, CA 94025 USA. Arizona State Univ, Dept Geol, Tempe, AZ 85287 USA. Lockheed Martin Astronaut, Denver, CO USA. US Geol Survey, Denver Fed Ctr, Denver, CO 80225 USA. Niels Bohr Inst Astron, Geofys Afdeling, DK-2100 Copenhagen, Denmark. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Hawaii Inst Geophys & Planetol, Honolulu, HI 96822 USA. Univ Paris 06, CNRS, Meteorol Dynam Lab, F-75252 Paris 05, France. Nagaoka Inst Snow & Ice Studies, NIED, Nagaoka, Niigata 18716, Japan. European Space Agcy, Estec, NL-2200 AG Noordwijk, Netherlands. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Univ Alaska, Inst Geophys, Fairbanks, AK 99775 USA. Case Western Reserve Univ, Dept Geol Sci, Cleveland, OH 44106 USA. Univ Virginia, Dept Environm Sci, Charlottesville, VA 22903 USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Univ Toledo, Dept Phys & Astron, Toledo, OH 43606 USA. Oklahoma State Univ, Dept Phys, Environm Sci Program, Stillwater, OK 74078 USA. Malin Space Sci Syst Inc, San Diego, CA 92191 USA. Univ Bristol, Dept Phys, HH Wills Phys Lab, Bristol BS8 1TL, Avon, England. Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. Univ Nebraska, Snow & Ice Res Grp, Lincoln, NE 68583 USA. Tech Univ Denmark, Danish Ctr Remote Sensing, DK-2800 Lyngby, Denmark. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Ohio State Univ, Byrd Polar Res Ctr, Columbus, OH 43210 USA. Alfred Wegener Inst Polar & Marine Res, D-27568 Bremerhaven, Germany. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. RP Lunar & Planetary Inst, 3600 Bay Area Blvd, Houston, TX 77058 USA. EM clifford@lpl.jsc.nasa.gov RI Bills, Bruce/C-1156-2008; Larsen, Janus/I-7479-2013; Dahl-Jensen, Dorthe/N-4401-2016; Wood, Stephen/R-5592-2016; OI Dahl-Jensen, Dorthe/0000-0002-1474-1948; Wood, Stephen/0000-0002-9330-434X; Howard, Alan/0000-0002-5423-1600 NR 201 TC 71 Z9 71 U1 2 U2 20 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 EI 1090-2643 J9 ICARUS JI Icarus PD APR PY 2000 VL 144 IS 2 BP 210 EP 242 DI 10.1006/icar.1999.6290 PG 33 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 304QB UT WOS:000086494000002 PM 11543391 ER PT J AU Nye, JF Durham, WB Schenk, PM Moore, JM AF Nye, JF Durham, WB Schenk, PM Moore, JM TI The instability of a south polar cap on Mars composed of carbon dioxide SO ICARUS LA English DT Article; Proceedings Paper CT 1st International Conference on Mars Polar Science and Exploration CY OCT 18-22, 1998 CL ALLEN, TX SP Lunar & Planetary Inst, Natl Aeronaut & Space Administrat Geolog, Int Glaciolog Soc DE Mars; Mars, surface; ices; geophysics AB If the martian south polar cap were composed of solid carbon dioxide, would it be sufficiently stable against collapse under its own weight? This question is examined in the light of new experiments on the creep of solid carbon dioxide and new high-resolution topographic mapping of the south polar cap. The conclusion from a simple model is that, with the strongest of three flow laws compatible with the measurements, CO2 is strong enough to support a cap of this material with thickness about 1800 m for 10(7) years or more, which is the age suggested by the cratering record. However, none of the three possible flow laws will allow a 3000-m cap, the thickness suggested by stereogrammetry, to survive for 10(7) years, indicating that the south polar ice cap is probably not composed of pure CO2 ice. (C) 2000 Academic Press. C1 Univ Bristol, HH Wills Phys Lab, Bristol BS8 1TL, Avon, England. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Lunar & Planetary Inst, Houston, TX 77058 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Univ Bristol, HH Wills Phys Lab, Tyndall Ave, Bristol BS8 1TL, Avon, England. EM durham1@llnl.gov NR 18 TC 41 Z9 41 U1 0 U2 3 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 EI 1090-2643 J9 ICARUS JI Icarus PD APR PY 2000 VL 144 IS 2 BP 449 EP 455 DI 10.1006/icar.1999.6306 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 304QB UT WOS:000086494000019 ER PT J AU Bennett, CV Kolner, BH AF Bennett, CV Kolner, BH TI Principles of parametric temporal imaging - Part I: System configurations SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article DE dispersive propagation; frequency mixing; phase modulation; temporal imaging; time lens; ultrafast measurement; ultrafast pulse propagation ID PULSE-COMPRESSION; ULTRASHORT PULSES; PHASE MODULATION; OPTICAL PULSES; TIME-LENSES; FIBER AB The recently developed process of temporal imaging expands or compresses time waveforms while preserving the shapes of their envelope profiles. A key element in a temporal imaging system is a time lens which imparts a quadratic phase modulation to the waveform being imaged. Several methods, such as electrooptic modulation, can be used to produce the phase modulation. In this paper, we concentrate on the parametric mixing of a signal waveform with a linearly chirped optical pump as the time lens mechanism. We analyze all single-lens system configurations including sum- and difference-frequency mixing schemes with positive and negative group velocity dispersions using temporal ray diagrams as an aid in understanding their operation. C1 Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90024 USA. Univ Calif Lawrence Livermore Natl Lab, Elect Engn Div, Livermore, CA 94551 USA. Univ Calif Davis, Dept Appl Sci, Davis, CA 95616 USA. RP Bennett, CV (reprint author), Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90024 USA. RI Bennett, Corey/C-2403-2009 OI Bennett, Corey/0000-0003-4365-5739 NR 37 TC 83 Z9 86 U1 1 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD APR PY 2000 VL 36 IS 4 BP 430 EP 437 DI 10.1109/3.831018 PG 8 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 301MP UT WOS:000086314200004 ER PT J AU Cullum, J Ruehli, A Zhang, T AF Cullum, J Ruehli, A Zhang, T TI A method for reduced-order modeling and simulation of large interconnect circuits and its application to PEEC models with retardation SO IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-ANALOG AND DIGITAL SIGNAL PROCESSING LA English DT Article DE Arnoldi; electronic interconnect package (EIP); interconnect circuits; iterative methods; Lanczos; MIMO systems; model reduction; reduced models; reduced-order systems; PEEC systems; time delays; transfer function ID ALGORITHM; REDUCTION AB The continuous improvement in the performance and the increases in the sizes of VLSI systems make electrical interconnect and package (EIP) design and modeling increasingly more important. Special software tools must be used for the design of high-performance VLSI systems. Furthermore, larger and faster systems require larger and more accurate circuit models. The partial element equivalent circuit (PEEC) technique is used for modeling such systems with three-dimensional full wave models. In this paper, we present a practical, readily parallelizable procedure for generating reduced-order frequency-domain models from general full wave PEEC systems, We use multiple expansion points, and piecemeal construction of pole-residue approximations to transfer functions of the PEEC systems, as was used in the complex frequency hopping algorithms. We consider general, multiple-input/multiple-output PEEC systems, Our block procedure consists of an outer loop of local approximations to the PEEC system, coupled with an inner loop where an iterative model-reduction method is applied to the local approximations. We systematically divide the complex frequency region of interest into small regions and construct local approximations to the PEEC system in each subregion. The local approximations are constructed so that the matrix factorizations associated with each of them are the size of the original system and independent of the order of the approximation. Results of computations on these local systems are combined to obtain a reduced-order model for the original PEEC system. We demonstrate the usefulness of our approach with three interesting examples. C1 Univ Calif Los Alamos Natl Lab, CIC 3, Los Alamos, NM 87545 USA. IBM Corp, Div Res, TJ Watson Res Ctr, Subsyst Technol & Applicat Lab, Yorktown Heights, NY 10598 USA. IBM Corp, Thomas J Watson Res Ctr, Dept Math Sci, Yorktown Heights, NY 10598 USA. RP Cullum, J (reprint author), Univ Calif Los Alamos Natl Lab, CIC 3, Los Alamos, NM 87545 USA. NR 35 TC 43 Z9 44 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 1057-7130 J9 IEEE T CIRCUITS-II JI IEEE Trans. Circuits Syst. II-Analog Digit. Signal Process. PD APR PY 2000 VL 47 IS 4 BP 261 EP 273 DI 10.1109/82.839662 PG 13 WC Engineering, Electrical & Electronic SC Engineering GA 310FE UT WOS:000086815200004 ER PT J AU Dang, GT Zhang, AP Ren, F Cao, XA Pearton, SJ Cho, H Han, J Chyi, JI Lee, CM Chuo, CC Chu, SNG Wilson, RG AF Dang, GT Zhang, AP Ren, F Cao, XA Pearton, SJ Cho, H Han, J Chyi, JI Lee, CM Chuo, CC Chu, SNG Wilson, RG TI High voltage GaN Schottky rectifiers SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article DE GaN; power electronics; rectifiers ID TEMPERATURE-DEPENDENCE; POWER DEVICES; TRANSISTORS; BREAKDOWN; DIODES; FIELD AB Mesa and planar GaN Schottky diode rectifiers vith reverse breakdown voltages (V-RB) up to 550 and >2000 V,respectively. hare been fabricated, The on-state resistance, R-ON, was 6 m Ohm.cm(2) and 0.8 Ohm cm(2), respectivetly, producing figure-of-merit values for (V-RB)(2)/R-ON in the range 5-48 MW.cm(-2). At low biases the reverse leakage current was proportional to the size of the rectifying contact perimeter, while at high biases the current was proportional to the area of this contact. These results suggest that at low reverse biases, the leakage is dominated bg the surface component, while at higher biases the bulk component dominates. On state voltages were 3.5 V for the 550 V diodes and greater than or equal to 15 for the 2 kV diodes. Reverse recovery times were <0.2 mu s for devices switched from a forward current density of similar to 500 A.cm(-2) to a reverse bias of 100 V. C1 Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Natl Cent Univ, Dept Elect Engn, Chungli 32054, Taiwan. Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. RP Pearton, SJ (reprint author), Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. EM spear@mse.ufl.edu RI Chyi, Jen-Inn/A-1799-2016 NR 21 TC 46 Z9 46 U1 0 U2 14 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9383 J9 IEEE T ELECTRON DEV JI IEEE Trans. Electron Devices PD APR PY 2000 VL 47 IS 4 BP 692 EP 696 DI 10.1109/16.830981 PG 5 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 302GD UT WOS:000086356600005 ER PT J AU Purschke, ML Adler, S Desmond, E Ewell, L Haggerty, J Kehayias, HJ Roth, R Witzig, C Pate, SS AF Purschke, ML Adler, S Desmond, E Ewell, L Haggerty, J Kehayias, HJ Roth, R Witzig, C Pate, SS TI The PHENIX Online Computing System SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 11th Conference on Real-Time Computer Applications in Nuclear, Particle, and Plasma Physics (RT 99) CY JUN 14-18, 1999 CL SANTA FE, NEW MEXICO SP Inst Electr & Electron Engineers, NPSS Techn Comm Comp Applicat Nucl & Plasma Sci AB The Online Computing System (ONCS) is responsible for the overall configuration and control of the PHENIX detector system Ell The experiment is made up of 4 spectrometer arms with a total number of 11 subdetectors, which need to be operated by a single control and monitoring system. This includes the configuration of the individual components of the readout system, as well as the control of the state of the detector's data flow. Furthermore, the ONCS system sets up the environment for the online monitoring of the detectors. The slow control of high voltages and other ancillary devices is also part of the system. The ONCS system is designed around a distributed computing model which relies on CORBA object oriented technology, the ROOT system as the backbone of the online monitoring, and EPICS for the control of the High Voltage systems. Issues regarding the use and implementation of these technologies in the ONCS system will be discussed, as well as the methods used to control the state and health of the PHENIX detector. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. New Mexico State Univ, Dept Phys, Las Cruces, NM 88003 USA. RP Purschke, ML (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 5 TC 1 Z9 1 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 APR PY 2000 VL 47 IS 2 BP 51 EP 55 DI 10.1109/23.846116 PN 1 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321UZ UT WOS:000087474200003 ER PT J AU Anikeev, K Bauer, G Furic, IK Holmgren, D Korn, A Kravchenko, I Mulhearn, M Ngan, P Paus, C Rakitine, A Rechenmacher, R Shah, T Sphicas, P Sumorok, K Tether, S Tseng, J AF Anikeev, K Bauer, G Furic, IK Holmgren, D Korn, A Kravchenko, I Mulhearn, M Ngan, P Paus, C Rakitine, A Rechenmacher, R Shah, T Sphicas, P Sumorok, K Tether, S Tseng, J TI Event-building and PC farm based Level-3 trigger at the CDF experiment SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 11th Conference on Real-Time Computer Applications in Nuclear, Particle, and Plasma Physics (RT 99) CY JUN 14-18, 1999 CL SANTA FE, NEW MEXICO SP Inst Electr & Electron Engineers, NPSS Techn Comm Comp Applicat Nucl & Plasma Sci AB In the technical design report the event building process at Fermilab's CDF experiment is required to function at an event rate of 300 events/sec. The events are expected to have an average size of 150 kBytes (kB) and are assembled from fragments of 16 readout locations. The fragment size from the different locations varies between 12 kB and 16 kB. Once the events are assembled they are fed into the Level-3 trigger which is based on processors running programs to filter events using the full event information. Computing power on the order of a second on a Pentium II processor is required per event. The architecture design is driven by the cost and is therefore based on commodity components: VME processor modules running VxWorks for the readout, an ATM switch for the event building, and Pentium PCs running Linux as an operation system for the Level-3 event processing. Pentium PCs are also used to receive events from the ATM switch and further distribute them to the processing nodes over multiple 100 Mbps Ethernets. Studies with a prototype of up to 10 VME readout modules and up to 4 receiving PCs are presented. This system is also a candidate for the CMS experiment at CERN. C1 MIT, Cambridge, MA 02139 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. CERN, Div EP, CH-1211 Geneva, Switzerland. RP Anikeev, K (reprint author), MIT, 77 Massachusetts Ave, Cambridge, MA 02139 USA. OI Holmgren, Donald/0000-0001-6701-7737 NR 2 TC 5 Z9 5 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 APR PY 2000 VL 47 IS 2 BP 65 EP 69 DI 10.1109/23.846119 PN 1 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321UZ UT WOS:000087474200006 ER PT J AU Nelson, RO Bourke, MAM Bowling, PS Cooper, GM Kozlowski, T Lara, PD Rose, CR Ross, JJ Seal, JR Williams, BC AF Nelson, RO Bourke, MAM Bowling, PS Cooper, GM Kozlowski, T Lara, PD Rose, CR Ross, JJ Seal, JR Williams, BC TI The LANSCE data acquisition system and SMARTS SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 11th Conference on Real-Time Computer Applications in Nuclear, Particle, and Plasma Physics (RT 99) CY JUN 14-18, 1999 CL SANTA FE, NEW MEXICO SP Inst Electr & Electron Engineers, NPSS Techn Comm Comp Applicat Nucl & Plasma Sci AB To meet the data acquisition requirements for five new neutron scattering instruments at the Los Alamos Neutron Science Center (LANSCE), we are building new systems using Web tools, commercial hardware and software, software developed by the controls community, and custom hardware developed by the neutron scattering community. To service these new instruments as well as seven existing instruments, our data acquisition system needs common software and hardware core capabilities and the means to flexibly integrate them while differentiating the needs of the diverse instrument suite. We report the features offered by our architecture that wilt simultaneously be functional and flexible, and then summarize the progress for hardware and software that can in fact meet the performance requirements demanded. We show how one of the five new instruments, the Spectrometer for Materials Research at Temperature and Stress, SMARTS, proposes to use the LANSCE data acquisition system for experiments that integrate event counting, real-time data analysis, and slow controls. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Nelson, RO (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 4 TC 4 Z9 4 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 APR PY 2000 VL 47 IS 2 BP 75 EP 79 DI 10.1109/23.846121 PN 1 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321UZ UT WOS:000087474200008 ER PT J AU Ljubicic, A Landgraf, JM LeVine, MJ Nelson, JM Roerich, D Schamback, JJ Schmischke, D Schulz, MW Struck, C Consiglio, CR Scheetz, R Zhao, Y AF Ljubicic, A Landgraf, JM LeVine, MJ Nelson, JM Roerich, D Schamback, JJ Schmischke, D Schulz, MW Struck, C Consiglio, CR Scheetz, R Zhao, Y TI The STAR experiment's data acquisition system SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 11th Conference on Real-Time Computer Applications in Nuclear, Particle, and Plasma Physics (RT 99) CY JUN 14-18, 1999 CL SANTA FE, NEW MEXICO SP Inst Electr & Electron Engineers, NPSS Techn Comm Comp Applicat Nucl & Plasma Sci AB STAR is one of the major experiments at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory, Upton, USA. RHIC together with STAR began commissioning in June 1999 while the first physics data will be gathered after October 1999. STAR will study ultrarelativistic heavy-ion collisions using its large TPC (Time Projection Chamber) in the first months of running. STAR's Data Acquisition system is a custom-built massively parallel system hierarchically organized into VME crates interconnected via a fast SCI network. The twelve Sector VME Crates each contain a Sector Broker CPU and twelve custom Receiver Boards, which are connected to the detector via a fiber optic link. Each Receiver Board hosts three custom Mezzanine Boards with a single Intel 1960HD CPU used to preprocess the data. The system is designed to process 100 events/s of incoming data keeping the output data rate on the order of 20 MB/s (1 event/s). Events will be selected using a third-level trigger utilizing real-time tracking. Built events are transported via SCSI to a workstation acting as an event buffer and forwarded to the RHIC Computing Facility via Gigabit Ethernet for final archiving. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Yale Univ, New Haven, CT USA. Univ Texas, Austin, TX 78712 USA. Univ Birmingham, Birmingham B15 2TT, W Midlands, England. Univ Frankfurt, D-6000 Frankfurt, Germany. RP Ljubicic, A (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. NR 8 TC 5 Z9 5 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 APR PY 2000 VL 47 IS 2 BP 99 EP 102 DI 10.1109/23.846125 PN 1 PG 4 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321UZ UT WOS:000087474200012 ER PT J AU Votava, M AF Votava, M CA CDF Online, DO Online, DART Collab TI Data acquisition systems at Fermilab SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 11th Conference on Real-Time Computer Applications in Nuclear, Particle, and Plasma Physics (RT 99) CY JUN 14-18, 1999 CL SANTA FE, NEW MEXICO SP Inst Electr & Electron Engineers, NPSS Techn Comm Comp Applicat Nucl & Plasma Sci AB Experiments at Fermilab require an ongoing program of development for high speed, distributed data acquisition systems. The physics program at the lab has recently started the operation of a Fixed Target run in which experiments are running the DART[1] data acquisition system. The CDF and D empty set experiments are preparing for the start of the next Collider run in mid 2000. Each will read out on the order of 1 million detector channels. In parallel, future experiments such as BTeV R&D and Mines have already started prototype and test beam work. BTeV in particular has challenging data acquisition system requirements with an input rate of 1500 Gbytes/sec into Level 1 buffers and a logging rate of 200 Mbytes/sec. This paper will present a general overview of these data acquisition systems on three fronts - those currently in use, those to be deployed for the Collider Run in 2000, and those proposed for future experiments. It will primarily focus on the CDF and DB architectures and tools. C1 Fermi Natl Accelerator Lab, Dept Comp Div, Batavia, IL 60510 USA. RP Votava, M (reprint author), Fermi Natl Accelerator Lab, Dept Comp Div, POB 500, Batavia, IL 60510 USA. NR 30 TC 1 Z9 1 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 APR PY 2000 VL 47 IS 2 BP 103 EP 108 DI 10.1109/23.846126 PN 1 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321UZ UT WOS:000087474200013 ER PT J AU LeVine, MJ Ljubicic, A Schulz, MW Scheetz, R Consiglio, C Padrazo, D Zhao, Y AF LeVine, MJ Ljubicic, A Schulz, MW Scheetz, R Consiglio, C Padrazo, D Zhao, Y TI The STAR DAQ receiver board SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 11th Conference on Real-Time Computer Applications in Nuclear, Particle, and Plasma Physics (RT 99) CY JUN 14-18, 1999 CL SANTA FE, NEW MEXICO SP Inst Electr & Electron Engineers, NPSS Techn Comm Comp Applicat Nucl & Plasma Sci AB Data digitized on the STAR TPC detector are transmitted via 1.5 Gbit/sec optical fiber to the DAO receiver boards (RB) located in Sector VME crates. The RE contains the optical receiver, Clink decoder, high speed bus to deliver data to three Mezzanines, which perform the processing. The RE back end provides an interface between VME64 and PCI, serving as interconnect between all of the Mezzanines, the VME bus, and resources local to the receiver board. Each Mezzanine hosts an Intel I960HD superscalar RISC CPU, which performs 2-dimensional cluster-finding and data formatting. Dual-ported VRAM provide storage for 12 TPC events. Incoming data are processed in real time by a bank of ASICs which perform pedestal subtraction, 10-bit to 8-bit compression via table lookup, and compilation of a sequence pointer bank for use by the CPU during cluster-finding. Communication among the I960s and the master CPU in the VME crate takes place through mailboxes and doorbells implemented in the I960-PCI bridge chips. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. RP LeVine, MJ (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. NR 3 TC 4 Z9 4 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 APR PY 2000 VL 47 IS 2 BP 127 EP 131 DI 10.1109/23.846131 PN 1 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321UZ UT WOS:000087474200018 ER PT J AU Rose, CR Hammonds, JP Nelson, RA Weizeorick, JT AF Rose, CR Hammonds, JP Nelson, RA Weizeorick, JT TI The LANL Neutron-Science-Center Time-Of-Flight/Position-Sensitive-Detect module: Status and progress SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 11th Conference on Real-Time Computer Applications in Nuclear, Particle, and Plasma Physics (RT 99) CY JUN 14-18, 1999 CL SANTA FE, NEW MEXICO SP Inst Electr & Electron Engineers, NPSS Techn Comm Comp Applicat Nucl & Plasma Sci AB This paper describes the progress and current status of a joint collaboration between Argonne National Laboratory (ANL) and the Los Alamos National Laboratory (LANL) Manuel Lujan Neutron Science Center (MLNSC) to develop and implement a Time-of-flight (TOF)/Position-Sensitive-Detector (PSD) VXI-based C-size neutron-event data-collection module. The LANL module, based on the ANL-developed hardware which uses field-programmable gate arrays (FPGAs) and analog-input-signal conditioning modules for a flexible topology capable of accepting either eight or 16 input channels, has been programmed and modified to incorporate more LANL-specific features such as improved peak detection, 24-bit time stamps, and 16-bit channel identification numbers which are all part of a 64-bit event record (2 by 32-bits wide). Using a backplane 10-MHz clock, timing resolution is +/-50 ns. The module uses two, frame first-in-first-out buffers (FIFOs), each 2-kwords deep, to accumulate event data at up to 330 kEvents/sec during a frame until the host computer can read it out. One FIFO is read while the other is being filled. The module does not use the ANL token-passing configuration for accessing data. Rather, it uses direct logical-address and register-based addressing modes. To interface with analog signals fi-om the neutron detectors, the module incorporates eight 72-pin single-inline-memory-module-size plug-in boards, called SIMs, which contain differential receivers, analog threshold comparators, and 8-bit analog-to-digital converters. A total of 16-analog channels are available if used in TOF mode, or eight channels if used in PSD mode. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Argonne Natl Lab, Chicago, IL 60510 USA. RP Rose, CR (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 2 TC 1 Z9 1 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 APR PY 2000 VL 47 IS 2 BP 151 EP 153 DI 10.1109/23.846136 PN 1 PG 3 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321UZ UT WOS:000087474200023 ER PT J AU Anthony, PL Crawley, HB Fischer, PA McKay, RL Meyer, WT AF Anthony, PL Crawley, HB Fischer, PA McKay, RL Meyer, WT TI CANbus and microcontroller use in the BaBar detector at SLAC SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 11th Conference on Real-Time Computer Applications in Nuclear, Particle, and Plasma Physics (RT 99) CY JUN 14-18, 1999 CL SANTA FE, NEW MEXICO SP Inst Electr & Electron Engineers, NPSS Techn Comm Comp Applicat Nucl & Plasma Sci AB The BaBar collaboration has chosen the Controller Area Network (CAN) [1] bus for its controls and monitoring field bus. In addition. the Motorola MC68HC70SX32 [2] microcontroller, which has a CAN interface, was chosen for the standard intelligent device for monitoring boards. This paper describes the CAN system used by BaBar and the embedded software that supports it. The General Monitoring Board (GMB) is presented as a specific example. The GMB is a CAN module that digitizes 32 differential analog signals and has eight bits of bi-directional I/O. C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Anthony, PL (reprint author), Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 2 TC 0 Z9 0 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 APR PY 2000 VL 47 IS 2 BP 166 EP 169 DI 10.1109/23.846140 PN 1 PG 4 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321UZ UT WOS:000087474200027 ER PT J AU Abrams, G Allison, S Anthony, P Kirkby, D Lewis, S Lionberger, C Meyer, T Morandin, M Olsen, J Paolucci, P Vasileiadis, G Zioulas, G AF Abrams, G Allison, S Anthony, P Kirkby, D Lewis, S Lionberger, C Meyer, T Morandin, M Olsen, J Paolucci, P Vasileiadis, G Zioulas, G CA BaBaR Detector Control Grp TI The detector control system for BaBaR SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 11th Conference on Real-Time Computer Applications in Nuclear, Particle, and Plasma Physics (RT 99) CY JUN 14-18, 1999 CL SANTA FE, NEW MEXICO SP Inst Electr & Electron Engineers, NPSS Techn Comm Comp Applicat Nucl & Plasma Sci AB The hardware/software system for the control of the BABAR Detector at PEP-II is described. The contributions of a large and diverse collaboration were channeled into a standard hardware selection (VME crate, embedded CPU, fieldbus, etc.) and a uniform software environment, EPICS (Experimental Physics and Industrial Control System). These choices, with a judicious naming convention in place, allowed a distributed and modular development of the control system, which was then integrated within the Online System in the Interaction Hall. The design of the software to complement the EPICS layer is presented. The coordination of controls activities with the rest of the Online is overseen by Run Control; the interface and functionality that controls supports is described. The archival storage, retrieval and analysis/display of the process control data is described, as well as the interface that allows access to this data with the same API as for our physics data. We also describe our modifications to the Online-wide messaging system ("cmlog") and our interface to the accelerator; PEP-II. Finally, we present our operational experiences with the control system. C1 Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Stanford Univ, Stanford, CA 94309 USA. Iowa State Univ, Ames, IA 50011 USA. Univ Padua, I-35131 Padua, Italy. Univ Maryland, College Pk, MD 20742 USA. Univ Naples, I-80125 Naples, Italy. Ecole Polytech, F-91128 Palaiseau, France. Univ Calif Irvine, Irvine, CA 92717 USA. RP Abrams, G (reprint author), Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RI Morandin, Mauro/A-3308-2016; OI Morandin, Mauro/0000-0003-4708-4240; Kirkby, David/0000-0002-8828-5463 NR 4 TC 1 Z9 1 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 APR PY 2000 VL 47 IS 2 BP 181 EP 185 DI 10.1109/23.846143 PN 1 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321UZ UT WOS:000087474200030 ER PT J AU Paolucci, P Cavallo, N Fabozzi, F Piccolo, D AF Paolucci, P Cavallo, N Fabozzi, F Piccolo, D TI The IFR online detector control at the BaBar experiment SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 11th Conference on Real-Time Computer Applications in Nuclear, Particle, and Plasma Physics (RT 99) CY JUN 14-18, 1999 CL SANTA FE, NEW MEXICO SP Inst Electr & Electron Engineers, NPSS Techn Comm Comp Applicat Nucl & Plasma Sci ID MUON AB The Instrumented Flux Return (IFR)[I] is one of the five subdetectors of the BaBar[2] experiment on the PEP II accelerator at SLAG. The IFR consists of 774 Resistive Plate Chamber (RPC) detectors, covering an area of about 2,000 m(2) and equipped with 3,000 Front-end Electronic Cards (FEC) reading about 50,000 channels (readout strips). The first aim of a B-factory experiment is to run continuously without any interruption and then the Detector Control system plays a very important role in order to reduce the dead-time due to the hardware problems. The I.N.F.N. group of Naples has designed and built the IFR Online Detector Control system (IODC)[3] in order to control and monitor the operation of this large number of detectors and of all the IFR subsystems: High Voltage, Low Voltage, Gas system, Trigger and DAQ crates. The IODC consists of 8 custom DAQ stations, placed around the detector and one central DAQ station based on VME technology and placed in electronic house. The IODC use VxWorks and EPICS to implement slow control data flow of about 2500 hardware channels and to develop part of the readout module consisting in about 3500 records. EPICS is interfaced with the BaBar Run Control through the Component Proxy and with the BaBar database (Objectivity) through the Archiver and KeyLookup processes. C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Ist Nazl Fis Nucl, Sezione Napoli, Complesso Monte Sant Angelo, I-80126 Naples, Italy. RP Paolucci, P (reprint author), Stanford Linear Accelerator Ctr, POB 4349, Stanford, CA 94309 USA. RI Cavallo, Nicola/F-8913-2012 NR 6 TC 0 Z9 0 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 APR PY 2000 VL 47 IS 2 BP 192 EP 195 DI 10.1109/23.846145 PN 1 PG 4 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321UZ UT WOS:000087474200032 ER PT J AU Lin, J Bieser, F Bordua, M Cherney, M Chrin, J Ferguson, I Ghazikhanian, V Gross, J Harper, G Howe, M Jacobson, S Kravtsov, P Lionberger, C McParland, C McShane, T Meier, J Sakrejda, I Yamamoto, E Zhang, W AF Lin, J Bieser, F Bordua, M Cherney, M Chrin, J Ferguson, I Ghazikhanian, V Gross, J Harper, G Howe, M Jacobson, S Kravtsov, P Lionberger, C McParland, C McShane, T Meier, J Sakrejda, I Yamamoto, E Zhang, W TI Hardware controls for the STAR experiment at RHIC SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 11th Conference on Real-Time Computer Applications in Nuclear, Particle, and Plasma Physics (RT 99) CY JUN 14-18, 1999 CL SANTA FE, NEW MEXICO SP Inst Electr & Electron Engineers, NPSS Techn Comm Comp Applicat Nucl & Plasma Sci AB A hardware controls system has been implemented for the STAR experiment at RHIC. Approximately 1000 parameters governing experiment operation are currently controlled and monitored. The system is based on the Experimental Physics and Industrial Control System (EPICS). The architecture of STAR hardware controls will be presented as well as the results of operation of the integrated baseline system. Novel features of the system include a specialized field bus (High-level Data Link Control - HDLC), new EPICS record support, Control DEVice (CDEV) interfaces to accelerator and magnet control systems, and C++ based communication between STAR online and Hardware Controls and their associated databases. C1 Creighton Univ, Dept Phys, Omaha, NE 68178 USA. Univ Calif Los Angeles, Dept Phys, Los Angeles, CA 90095 USA. Kent State Univ, Dept Phys, Kent, OH 44242 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Moscow Engn Phys Inst, Moscow 115409, Russia. Univ Washington, Dept Phys, Seattle, WA 98195 USA. RP Lin, J (reprint author), Creighton Univ, Dept Phys, Omaha, NE 68178 USA. NR 12 TC 4 Z9 4 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 APR PY 2000 VL 47 IS 2 BP 210 EP 213 DI 10.1109/23.846148 PN 1 PG 4 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321UZ UT WOS:000087474200036 ER PT J AU Mueller, D Gates, DA Ferron, JR AF Mueller, D Gates, DA Ferron, JR TI Upgrade for the National Spherical Torus Experiment control computer SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 11th Conference on Real-Time Computer Applications in Nuclear, Particle, and Plasma Physics (RT 99) CY JUN 14-18, 1999 CL SANTA FE, NEW MEXICO SP Inst Electr & Electron Engineers, NPSS Techn Comm Comp Applicat Nucl & Plasma Sci ID RECONSTRUCTION AB The National Spherical Torus Experiment (NSTX) is a proof of scientific principle experiment as a magnetic fusion containment device. A primary goal of NSTX operations is control of the plasma current, position and shape in real time for a wide range of plasma pressure and current density profiles. In order to employ the best calculation of the plasma current, position and shape, it is planned to implement the equilibrium analysis code, EFIT[1], in real-time, RTEFIT[2]. EFIT inverts the Grad-Shafranov equation and performs a least squares fit to the magnetics data. EFIT and RTEFIT are also capable of providing the plasma current profile and the plasma pressure profile from analysis of diagnostic data. The calculation time for RTEFIT using the present NSTX control computer system is comparable to the expected energy confinement time on NSTX and is thus slower than desired. A computer upgrade based upon the new G4 (MPC7400) processors will permit the RTEFIT calculation loop to complete in about 2 ms. The presence of the passive plates further complicates the control algorithm to be used in conjunction with RTEFIT. The planned approach is to measure the eddy currents in the passive plates and to use the transient response of the coils to minimize the total shell current effect. C1 Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. Gen Atom, San Diego, CA 92186 USA. RP Mueller, D (reprint author), Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 6 TC 0 Z9 0 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 APR PY 2000 VL 47 IS 2 BP 219 EP 221 DI 10.1109/23.846150 PN 1 PG 3 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321UZ UT WOS:000087474200038 ER PT J AU Gates, DA Mueller, D Neumeyer, C Ferron, JR AF Gates, DA Mueller, D Neumeyer, C Ferron, JR TI Control system development plan for the National Spherical Torus Experiment SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 11th Conference on Real-Time Computer Applications in Nuclear, Particle, and Plasma Physics (RT 99) CY JUN 14-18, 1999 CL SANTA FE, NEW MEXICO SP Inst Electr & Electron Engineers, NPSS Techn Comm Comp Applicat Nucl & Plasma Sci AB The National Spherical Torus Experiment (NSTX) has as one of its primary goals the demonstration of the attractiveness of the spherical torus concept as a fusion power plant. Central to this goal is the achievement of high plasma beta (=2 mu(0) /B-2 a measure of the efficiency of a magnetic plasma confinement system). It has been demonstrated both theoretically and experimentally that the maximum achievable beta is a strong function of both local and global plasma parameters. It is therefore important to optimize control of the plasma. To this end a phased development plan for digital plasma control on NSTX is presented. The relative level of sophistication of the control system software and hardware will be increased according to the demands of the experimental program in a three phase plan. During Day 0 (first plasma), a simple coil current control algorithm will initiate plasma operations. During the second phase (Day 1) of plasma operations the control system will continue to use the preprogrammed algorithm to initiate plasma breakdown but will then change over to a rudimentary plasma control scheme based on linear combinations of measured plasma fields and fluxes. The third phase of NSTX plasma control system development will utilize the rtEFIT code, first used on DIII-D, to determine, in real-time, the full plasma equilibrium by inverting the Grad-Shafranov equation. The details of the development plan, including a description of the proposed hardware will be presented. C1 Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. Gen Atom, San Diego, CA 92186 USA. RP Gates, DA (reprint author), Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 1 TC 4 Z9 4 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 APR PY 2000 VL 47 IS 2 BP 222 EP 224 DI 10.1109/23.846151 PN 1 PG 3 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321UZ UT WOS:000087474200039 ER PT J AU Shimojima, M Kilminster, BJ McFarland, KS Vaiciulis, A Holmgren, DJ AF Shimojima, M Kilminster, BJ McFarland, KS Vaiciulis, A Holmgren, DJ TI Consumer-server/logger system for the CDF experiment SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 11th Conference on Real-Time Computer Applications in Nuclear, Particle, and Plasma Physics (RT 99) CY JUN 14-18, 1999 CL SANTA FE, NEW MEXICO SP Inst Electr & Electron Engineers, NPSS Techn Comm Comp Applicat Nucl & Plasma Sci AB The level-3 trigger system for the CDF experiment runs on a farm of Linux PCs. Events that pass this trigger system are collected and logged to disk by a logger process running on an SGI Origin 200 GIGAchannel server. The system must support data logging at 75 Hz for 250 KB events. In addition, some of the events are sent to remote consumer processes for online monitoring. The Consumer-Server/Logger system inherently behaves like an intelligent hardware hub, maintaining connectivity between these large numbers (similar to 200) of Level-3 farm nodes, consumer processes, and the logging hardware. The farm nodes and the consumer processes are networked using multiple Fast Ethernet interfaces while the disk subsystem of 0.5-1 TB capacity is connected via dual Fibre Channel arbitrated loops. Different functions of the Consumer-Server/Logger are implemented as distinct state machines to keep each section of the code as simple and robust as possible. In this paper, we describe the first implementation of the system and present initial performance results conducted at CDF. C1 Univ Tsukuba, Tsukuba, Ibaraki 3058571, Japan. Univ Rochester, Rochester, NY 14627 USA. Fermilab, Batavia, IL 60510 USA. RP Shimojima, M (reprint author), Univ Tsukuba, Tsukuba, Ibaraki 3058571, Japan. OI Holmgren, Donald/0000-0001-6701-7737 NR 4 TC 1 Z9 1 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 APR PY 2000 VL 47 IS 2 BP 236 EP 239 DI 10.1109/23.846154 PN 1 PG 4 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321UZ UT WOS:000087474200042 ER PT J AU Canal, P Kowalkowski, J Maeshima, K Yu, J Wenzel, H Snow, J Arisawa, T Ikado, K Shimojima, M Veramendi, G AF Canal, P Kowalkowski, J Maeshima, K Yu, J Wenzel, H Snow, J Arisawa, T Ikado, K Shimojima, M Veramendi, G TI Online monitoring in the upcoming Fermilab Tevatron runII SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 11th Conference on Real-Time Computer Applications in Nuclear, Particle, and Plasma Physics (RT 99) CY JUN 14-18, 1999 CL SANTA FE, NEW MEXICO SP Inst Electr & Electron Engineers, NPSS Techn Comm Comp Applicat Nucl & Plasma Sci AB We describe the online event monitoring systems using ROOT [1] for the CDF and DO collaborations in the upcoming Fermilab Tevatron runII. The CDF and DO experiments consist of many detector subsystems and will run in a high rate large bandwidth data transfer environment. In the experiments, it is crucial to monitor the performance of each subsystem and the integrity of the data, in real time with minimal interruption. ROOT is used as the main analysis tool for the monitoring systems and its GUI is used to browse the results via socket, allowing multiple GUI client connections. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Karlsruhe, Inst Expt Kernphys, D-76128 Karlsruhe, Germany. Langston Univ, Langston, OK 73050 USA. Waseda Univ, Tokyo 169, Japan. Univ Tsukuba, Tsukuba, Ibaraki 3058571, Japan. Ernest Orlando Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Canal, P (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 4 TC 1 Z9 1 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 APR PY 2000 VL 47 IS 2 BP 240 EP 243 DI 10.1109/23.846155 PN 1 PG 4 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321UZ UT WOS:000087474200043 ER PT J AU Gay, C Guo, Y Nahn, S Patrick, J Vejcik, S Votava, M AF Gay, C Guo, Y Nahn, S Patrick, J Vejcik, S Votava, M TI CDFVME - Software framework for testing VME boards SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 11th Conference on Real-Time Computer Applications in Nuclear, Particle, and Plasma Physics (RT 99) CY JUN 14-18, 1999 CL SANTA FE, NEW MEXICO SP Inst Electr & Electron Engineers, NPSS Techn Comm Comp Applicat Nucl & Plasma Sci AB New VME based boards are being produced for the Run II of the Collider Detector at Fermilab (CDF). These boards are being developed and tested at both Fermilab and offsite institutions. A software framework called CDFVME has been developed in which DAQ code can be easily written to control such boards in a test stand. The framework has been used to perform diagnostics at single board, multi-board, and multi-crate levels. This software framework runs on Unix, Linux and Windows NT platforms with a Java GUI communicating via LAN to multiple intelligent front end VME crates. All distributed processes are managed by a custom CORBA based software. The system has been ported to Motorola 68K and PPC front end processors running the VxWorks real-time kernel [1]. C1 Yale Univ, Dept Phys, New Haven, CT 06520 USA. Fermilab, Batavia, IL 60510 USA. RP Gay, C (reprint author), Yale Univ, Dept Phys, POB 208120, New Haven, CT 06520 USA. NR 0 TC 1 Z9 1 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 APR PY 2000 VL 47 IS 2 BP 259 EP 262 DI 10.1109/23.846159 PN 1 PG 4 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321UZ UT WOS:000087474200047 ER PT J AU Parashar, N Bardon, O Goodwin, R Hansen, S Hoeneisen, B Podstavkov, V Uvarov, S Wood, D AF Parashar, N Bardon, O Goodwin, R Hansen, S Hoeneisen, B Podstavkov, V Uvarov, S Wood, D TI Real-time data processing in the muon system of the D0 detector SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 11th Conference on Real-Time Computer Applications in Nuclear, Particle, and Plasma Physics (RT 99) CY JUN 14-18, 1999 CL SANTA FE, NEW MEXICO SP Inst Electr & Electron Engineers, NPSS Techn Comm Comp Applicat Nucl & Plasma Sci AB This paper presents a real-time application of the 16-bit fixed point Digital Signal Processors (DSPs), in the Muon System of the DO detector located at the Fermilab Tevatron, presently the world's highest-energy hadron collider. As part of the Upgrade for a run beginning in the year 2000, the system is required to process data at an input event rate of 10 KHz without incurring significant deadtime in readout. The ADSP21csp01 processor has high I/O bandwidth, single cycle instruction execution and fast task switching support to provide efficient multisignal processing. The processor's internal memory consists of 4K words of Program Memory and 4K words of Data Memory. In addition there is an external memory of 32K words for general event buffering and 16K words of Dual Port Memory for input data queuing. This DSP fulfills the requirement of the Muon subdetector systems for data readout. All error handling, buffering, formatting and transferring of the data to the various trigger levels of the data acquisition system is done in software. The algorithms developed for the system complete these tasks in about 20 mu s per event. C1 Univ Los Andes, Bogota, Colombia. Univ San Francisco, Quito, Ecuador. Petersburg Nucl Phys Inst, St Petersburg, Russia. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Northeastern Univ, Boston, MA 02115 USA. RP Parashar, N (reprint author), Univ Los Andes, Bogota, Colombia. OI Hoeneisen, Bruce/0000-0002-6059-4256 NR 3 TC 1 Z9 1 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 APR PY 2000 VL 47 IS 2 BP 276 EP 279 DI 10.1109/23.846163 PN 1 PG 4 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321UZ UT WOS:000087474200051 ER PT J AU Malone, R Wang, XJ AF Malone, R Wang, XJ TI Using a commercial mathematics software package for on-line analysis at the BNL Accelerator Test Facility SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 11th Conference on Real-Time Computer Applications in Nuclear, Particle, and Plasma Physics (RT 99) CY JUN 14-18, 1999 CL SANTA FE, NEW MEXICO SP Inst Electr & Electron Engineers, NPSS Techn Comm Comp Applicat Nucl & Plasma Sci AB By writing both a custom Windows NT(TM) dynamic link library and generic companion server software, the intrinsic functions of MathSoft's Mathcad(TM) have been extended with new capabilities which permit direct access to the control system databases of Brookhaven National Laboratory's Accelerator Test Facility. Under this scheme, a Mathcad worksheet executing on a personal computer becomes a client which can both import and export data to a control system server via a network stream socket connection. The result is an alternative, mathematically oriented view of controlling the accelerator interactively. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. RP Malone, R (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. NR 2 TC 0 Z9 0 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 APR PY 2000 VL 47 IS 2 BP 288 EP 292 DI 10.1109/23.846166 PN 1 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321UZ UT WOS:000087474200054 ER PT J AU Steinberg, P Chi, CY Chiu, M Cole, B Cunitz, H Markacs, S Nagle, JL Sippach, W Zajc, WA Zhang, L Fisher, B Fried, J Haggerty, J Lin, S Purschke, M AF Steinberg, P Chi, CY Chiu, M Cole, B Cunitz, H Markacs, S Nagle, JL Sippach, W Zajc, WA Zhang, L Fisher, B Fried, J Haggerty, J Lin, S Purschke, M TI The data collection modules and ATM-based event builder for the PHENIX experiment at RHIC SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 11th Conference on Real-Time Computer Applications in Nuclear, Particle, and Plasma Physics (RT 99) CY JUN 14-18, 1999 CL SANTA FE, NEW MEXICO SP Inst Electr & Electron Engineers, NPSS Techn Comm Comp Applicat Nucl & Plasma Sci AB The PHENIX experiment at RHIC will study 200 AGeV Au+Au collisions as well as pp and pA collisions at higher energies. In order to study hard processes or high-mass vector mesons, which have small cross sections, PHENIX emphasizes measuring charged hadrons, leptons, and photons at a high rate in a limited aperture. At design RHIC luminosity, the minimum-bias interaction rate will be approximately 1000 Hz with an average zero-suppressed event size of 200 kB. We will discuss two major parts of the PHENIX online system: the Data Collection Modules (DCM) and the Event Builder (EvB). The DCMs use a combination of FPGAs and DSPs to perform online pedestal subtraction, zero-suppression, and data formatting. They have been fully constructed and tested and are able to deliver data at a maximum rate of 160 MB/s. The Event Builder consists of commercially available PCs and a 10 Gb/s ATM switch. The software for it has been developed using Windows NT, Winsock-2 and Visual C++, allowing a fully object-oriented design. Currently, we are running configurations with up to 4 sources and 3 destinations that can deliver data at similar to 10 MB/sec/node and performance is improving steadily. C1 Columbia Univ, Nevis Labs, Irvington, NY 10533 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Steinberg, P (reprint author), Columbia Univ, Nevis Labs, Irvington, NY 10533 USA. NR 4 TC 2 Z9 2 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 APR PY 2000 VL 47 IS 2 BP 304 EP 308 DI 10.1109/23.846169 PN 1 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321UZ UT WOS:000087474200057 ER PT J AU Desmond, E Adler, S Ewell, L Haggerty, J Kehayias, HJ Pate, S Purschke, M Roth, R Witzig, C AF Desmond, E Adler, S Ewell, L Haggerty, J Kehayias, HJ Pate, S Purschke, M Roth, R Witzig, C TI Use of CORBA in the PHENIX distributed online computing system SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 11th Conference on Real-Time Computer Applications in Nuclear, Particle, and Plasma Physics (RT 99) CY JUN 14-18, 1999 CL SANTA FE, NEW MEXICO SP Inst Electr & Electron Engineers, NPSS Techn Comm Comp Applicat Nucl & Plasma Sci AB The PHENIX online control system is responsible for the configuration, control and monitoring of the PHENIX detector data acquisition system and ancillary control hardware, and the collection and archiving of the event data. The detector consists of 11 distinct subsystems, which are distributed physically and partitioned logically while ultimately being combined into a single operating unit. The online system consists of a large number of embedded commercial and custom processors as well as custom software processes which are involved in the collection. monitoring and control of the detector and the event data. These processing elements are distributed over a diverse set of computing platforms including VME based Power PC controllers, Pentium based NT systems, and SUN Solaris SPARC processors. CORBA has been adopted as the standard communication mechanism for PHENIX online system. This paper will describe the design, implementation and use of CORBA to achieve a uniform and platform independent control environment while providing for the access, control and monitoring of the online detector elements over the distributed and diverse control environment. Synchronous and asynchronous communication issues will be discussed as well as the development of CORBA compliant components which were developed to achieve client / server isolation and deterministic system behavior. The use and interaction between JAVA based clients and C++ based CORBA servers to further achieve a platform neutral environment will be presented. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. New Mexico State Univ, Dept Phys, Las Cruces, NM 88003 USA. RP Desmond, E (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 6 TC 1 Z9 1 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 APR PY 2000 VL 47 IS 2 BP 344 EP 347 DI 10.1109/23.846178 PN 1 PG 4 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321UZ UT WOS:000087474200066 ER PT J AU Adler, C Berger, J Demello, M Flierl, D Landgraf, J Lange, JS LeVine, MJ Lindenstruth, V Ljubicic, A Nelson, J Roehrich, D Schafer, E Schambach, JJ Schmischke, D Schulz, MW Stock, R Struck, C Yepes, P AF Adler, C Berger, J Demello, M Flierl, D Landgraf, J Lange, JS LeVine, MJ Lindenstruth, V Ljubicic, A Nelson, J Roehrich, D Schafer, E Schambach, JJ Schmischke, D Schulz, MW Stock, R Struck, C Yepes, P TI The proposed level-3 trigger system for STAR SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 11th Conference on Real-Time Computer Applications in Nuclear, Particle, and Plasma Physics (RT 99) CY JUN 14-18, 1999 CL SANTA FE, NEW MEXICO SP Inst Electr & Electron Engineers, NPSS Techn Comm Comp Applicat Nucl & Plasma Sci AB The level-3 trigger system of the STAR experiment will in the final stage consist of a farm of 24 ALPHA/Linux processors, interconnected by SCI (Scalable Coherent Interface). The system will perform online tracking of N(track)greater than or equal to 8000 tracks per event (N(point)less than or equal to 45 per track). The track data will be transfered to a global level-3 CPU (expected data transfer rate similar or equal to 48 MB/s), performing online event analysis tasks (e.g. invariant mass reconstruction) with a design trigger input rate of R=100 Hz (R=20 Hz for a prototype system). C1 Univ Frankfurt, D-60486 Frankfurt, Germany. Rice Univ, Houston, TX 77251 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Heidelberg, D-69120 Heidelberg, Germany. Univ Birmingham, Birmingham B15 2TT, W Midlands, England. Univ Bergen, N-5007 Bergen, Norway. Max Planck Inst Phys, D-80805 Munich, Germany. Univ Texas, Austin, TX 78712 USA. RP Lange, JS (reprint author), Univ Frankfurt, August Euler Str 6, D-60486 Frankfurt, Germany. NR 4 TC 2 Z9 2 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 APR PY 2000 VL 47 IS 2 BP 358 EP 361 DI 10.1109/23.846181 PN 1 PG 4 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321UZ UT WOS:000087474200069 ER PT J AU Calvet, D Gachelin, O Huet, M Le Du, P Mandjavidze, I Blair, R Dawson, J Schlereth, J Abolins, M Ermoline, Y AF Calvet, D Gachelin, O Huet, M Le Du, P Mandjavidze, I Blair, R Dawson, J Schlereth, J Abolins, M Ermoline, Y TI The ATLAS High Level Trigger ATM testbed SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 11th Conference on Real-Time Computer Applications in Nuclear, Particle, and Plasma Physics (RT 99) CY JUN 14-18, 1999 CL SANTA FE, NEW MEXICO SP Inst Electr & Electron Engineers, NPSS Techn Comm Comp Applicat Nucl & Plasma Sci AB This paper describes an implementation of the High Level Trigger for the ATLAS experiment on a large testbed based on a 32 node switch attached to data sources, event processing units, supervisor modules and interface to the level-1 trigger. We describe the functionality of each component and investigate its performance. We show the operation of the complete system and outline future activities. C1 CEA Saclay, DAPNIA, F-91191 Gif Sur Yvette, France. Argonne Natl Lab, Argonne, IL 60439 USA. Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. RP Calvet, D (reprint author), CEA Saclay, DAPNIA, F-91191 Gif Sur Yvette, France. NR 7 TC 0 Z9 0 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 APR PY 2000 VL 47 IS 2 BP 367 EP 370 DI 10.1109/23.846183 PN 1 PG 4 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321UZ UT WOS:000087474200071 ER PT J AU Borcherding, F Grunendahl, S Johnson, M Yip, K AF Borcherding, F Grunendahl, S Johnson, M Yip, K TI The level 1 central tracking trigger for the D circle divide upgrade SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 11th Conference on Real-Time Computer Applications in Nuclear, Particle, and Plasma Physics (RT 99) CY JUN 14-18, 1999 CL SANTA FE, NEW MEXICO SP Inst Electr & Electron Engineers, NPSS Techn Comm Comp Applicat Nucl & Plasma Sci ID FIBER AB The DO level 1 tracking trigger uses data from the scintillating fiber tracker, the central and forward preshower detectors, the muon system and the calorimeter. Tracks are found in the scintillating fiber tracker with transverse momentum greater than 1.5 GeV/c. The tracks are matched with hits in the central preshower detector and the muon system for electron and muon tagging. Preshower clusters are also used for identifying photon candidates. These multi detector triggers are then sent to the level 1 Trigger Framework where they are further combined with the calorimeter to create the final level 1 trigger. This paper presents an overview of the level 1 trigger system with emphasis on the use of large programmable logic devices (PLD's) in an extensible system architecture that allows complex, multi detector triggers. C1 Fermilab Astrophys Ctr, Batavia, IL 60510 USA. RP Borcherding, F (reprint author), Fermilab Astrophys Ctr, POB 500, Batavia, IL 60510 USA. RI Yip, Kin/D-6860-2013 OI Yip, Kin/0000-0002-8576-4311 NR 6 TC 0 Z9 0 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 APR PY 2000 VL 47 IS 2 BP 381 EP 385 DI 10.1109/23.846186 PN 1 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321UZ UT WOS:000087474200074 ER PT J AU Menichelli, D Pirollo, S Li, Z AF Menichelli, D Pirollo, S Li, Z TI A detailed microscopic analysis of deep levels in heavily irradiated-medium resistivity silicon detectors SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article DE deep levels; I-DLTS; radiation effect; silicon; TSC ID RADIATION; NEUTRON; DEFECTS; TSC AB In this work we show a detailed deep levels analysis (an energy resolution of 50 meV was reached) of a set of medium resistivity silicon samples, irradiated up to a fluence of 2.5 10(15) n/cm(2). In order to discriminate the large number of deep levels which appear to overlap their contributions in TSC and I-DLTS spectra, we adapted an innovative numerical procedure of data analysis which determines a set of deep levels that can account for both TSC and I-DLTS spectra, We finally obtained a consistent and detailed description of deep level population, clearly showing its evolution with fluence, Some results seem to suggest the possibility of quasi-continuous distributions of localized states inside the gap. C1 Ist Nazl Fis Nucl, I-50139 Florence, Italy. DEF Firenze, Dipartimento Energet S Stecco, I-50139 Florence, Italy. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Ist Nazl Fis Nucl, I-50139 Florence, Italy. EM menichelli@ingfi1.ing.unifi.it NR 25 TC 9 Z9 9 U1 1 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 APR PY 2000 VL 47 IS 2 BP 446 EP 451 DI 10.1109/23.846278 PN 2 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321VE UT WOS:000087474700007 ER PT J AU Sutton, PM Hansen, CD AF Sutton, PM Hansen, CD TI Accelerated isosurface extraction in time-varying fields SO IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS LA English DT Article; Proceedings Paper CT IEEE 99 Symposium on Information Visualization (InfoVIS 99) CY 1999 CL SAN FRANCISCO, CA DE isosurface; time-dependent scalar field visualization; multiresolution methods; octree; bricking; unstructured grid visualization; out-of-core visualization AB For large time-varying data sets, memory and disk limitations can lower the performace of visualization applications. Algorithms and data structures must be explicitly designed to handle these data sets in order to achieve more interactive rates. The Temporal Branch-on-Need Octree (T-BON) extends the three-dimensional branch-on-need octree for time-varying isosurface extraction. This data structure minimizes the impact of the I/O bottleneck by reading from disk only those portions of the search structure and data necessary to construct the current isosurface. By performing a minimum of I/O and exploiting the hierarchical memory found in modern CPUs, the T-BON algorithm achieves high performance isosurface extraction in time-varying fields. This paper extends earlier work on the T-BON data structure by including techniques for better memory utilization, out-of-core isosurface extraction, and support for nonrectilinear grids. Results from testing the T-BON algorithm on large data sets show that its performance is similar to that of the three-dimensional branch-on-need octree for static data sets while providing substantial advantages for time-varying fields. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Utah, Dept Comp Sci, Salt Lake City, UT 84124 USA. RP Lawrence Livermore Natl Lab, POB 808,L-561, Livermore, CA 94550 USA. EM psutton@llnl.gov; hansen@cs.utah.edu NR 26 TC 23 Z9 24 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 1077-2626 EI 1941-0506 J9 IEEE T VIS COMPUT GR JI IEEE Trans. Vis. Comput. Graph. PD APR-JUN PY 2000 VL 6 IS 2 BP 98 EP 107 DI 10.1109/2945.856992 PG 10 WC Computer Science, Software Engineering SC Computer Science GA 332QY UT WOS:000088086000002 ER PT J AU Granite, EJ Pennline, HW Hargis, RA AF Granite, EJ Pennline, HW Hargis, RA TI Novel sorbents for mercury removal from flue gas SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID ACTIVATED CARBONS; CATALYSTS; IMPREGNATION; ADSORPTION; REDUCTION; EMISSION; SURFACE; VAPOR AB A laboratory-scale packed-bed reactor system is used to screen sorbents for their capability to remove elemental mercury from various carrier gases. When the carrier gas is argon, an online atomic fluorescence spectrophotometer (AFS), used in a continuous mode, monitors the elemental mercury concentration in the inlet and outlet streams of the packed-bed reactor. The mercury concentration in the reactor inlet gas and the reactor temperature are held constant during a test. For more complex carrier gases, the capacity is determined off-line by analyzing the spent sorbent with either a cold vapor atomic absorption spectrophotometer (CVAAS) or an inductively coupled argon plasma atomic emission spectrophotometer (ICP-AES). The capacities and breakthrough times of several commercially available activated carbons as well as novel sorbents were determined as a function of various parameters. The mechanisms of mercury removal by the sorbents are suggested by combining the results of the packed-bed testing with various analytical results. C1 US Dept Energy, Natl Energy Technol Lab, Pittsburgh, PA 15236 USA. RP Granite, EJ (reprint author), US Dept Energy, Natl Energy Technol Lab, POB 10940, Pittsburgh, PA 15236 USA. NR 55 TC 238 Z9 275 U1 8 U2 77 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 APR PY 2000 VL 39 IS 4 BP 1020 EP 1029 DI 10.1021/ie990758v PG 10 WC Engineering, Chemical SC Engineering GA 302GM UT WOS:000086357400021 ER PT J AU Siriwardane, RV Gardner, T Poston, JA Fisher, EP Miltz, A AF Siriwardane, RV Gardner, T Poston, JA Fisher, EP Miltz, A TI Spectroscopic characterization of nickel containing desulfurization sorbents SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID ZINC AB Characterization of nickel-containing desulfurization sorbents was performed by X-ray photoelectron spectroscopy, scanning electron microscopy/energy-dispersive spectroscopy, thermogravimetric analysis, and atomic absorption analysis, Sorbent pellets were tested with simulated coal-derived hot fuel gas containing H2S, in a bench-scale fixed-bed reactor. Analysis was performed on both the interior and exterior of the sorbent pellets after both sulfidations and regenerations. In the sulfided sorbents, migration of nickel to the grain surface was observed at the exterior of the sorbent pellet. The nickel migration was less significant at the grain surface of the interior of the pellet. Changes in the oxidation state of the nickel were also observed at the outer surface of the pellet. The sulfur concentration was significantly higher at the outer surface of the pellet, indicating diffusional resistance of the fuel gas to the pellet interior. C1 US Dept Energy, Natl Energy Technol Lab, Morgantown, WV 26507 USA. EG&G TSWV Inc, Morgantown, WV 26507 USA. RP Siriwardane, RV (reprint author), US Dept Energy, Natl Energy Technol Lab, POB 880,3610 Collins Ferry Rd, Morgantown, WV 26507 USA. NR 10 TC 18 Z9 19 U1 0 U2 0 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 APR PY 2000 VL 39 IS 4 BP 1106 EP 1110 DI 10.1021/ie990521z PG 5 WC Engineering, Chemical SC Engineering GA 302GM UT WOS:000086357400032 ER PT J AU Wang, J Chia, WJ Chung, YW Liu, CT AF Wang, J Chia, WJ Chung, YW Liu, CT TI Interaction of H2O and O-2 with Ni3Fe and their effects on ductility SO INTERMETALLICS LA English DT Article DE intermetallics; miscellaneous; brittleness and ductility; environmental embrittlement; surface properties ID ENVIRONMENTAL EMBRITTLEMENT; HYDROGEN EMBRITTLEMENT; WATER-VAPOR; SURFACE; FE(001) AB Possible reasons for the high ductility of Ni3Fe and its insensitivity toward the testing environment have been investigated. Thermal desorption experiments have shown that water dissociates on clean Ni3Fe surfaces to produce atomic hydrogen. Ductility measurements of cast and cold-rolled polycrystalline Ni3Fe demonstrated that the reduced ductility was obtained only when the testing was performed with oxygen carefully removed. X-ray photoemission studies indicate that oxygen interacts with water to form hydroxyls, thereby suppressing the production of atomic hydrogen. Hydrogen desorption from the Ni3Fe surface requires a lower activation energy, resulting in a smaller surface hydrogen concentration at a given temperature. Hence it is possible that there is insufficient hydrogen to cause the nucleation and growth of brittle cracks for severe embrittlement. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Wang, J (reprint author), Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. RI Chung, Yip-Wah/B-7506-2009; OI Liu, Chain Tsuan/0000-0001-7888-9725 NR 10 TC 10 Z9 10 U1 0 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0966-9795 J9 INTERMETALLICS JI Intermetallics PD APR PY 2000 VL 8 IS 4 BP 353 EP 357 DI 10.1016/S0966-9795(99)00091-6 PG 5 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 299AW UT WOS:000086174500005 ER PT J AU Chan, KS Bodner, SR Munson, DE AF Chan, KS Bodner, SR Munson, DE TI Application of isochronous healing curves in predicting damage evolution in a salt structure SO INTERNATIONAL JOURNAL OF DAMAGE MECHANICS LA English DT Article ID ROCK-SALT; INELASTIC FLOW AB A treatment of damage healing is present for rock salt, formulated within the framework of continuum damage mechanics. The concept of an isochronous healing surface, which is a locus of points in a stress space for which the times of healing are identical, is proposed and derived from the healing formulation in order to establish the initial stresses for the onset of healing and the evolution of healing with time and stress. The characteristics of the isochronous healing curves are identified and compared against those of isochronous failure curves and the dilatancy boundary. Isochronous healing curves for clean and argillaceous (containing clay particles) salt are developed and evaluated against laboratory data. Subsequently, the isochronous healing curves are used to predict the healing response of damage in the disturbed rock zone of an air intake shaft in a salt structure. C1 SW Res Inst, Main Off, San Antonio, TX 78228 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Technion Israel Inst Technol, Dept Mech Engn, IL-32000 Haifa, Israel. RP Chan, KS (reprint author), SW Res Inst, Main Off, 6220 Culebra Rd,PO Drawer 28510, San Antonio, TX 78228 USA. NR 25 TC 2 Z9 2 U1 1 U2 1 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 USA SN 1056-7895 J9 INT J DAMAGE MECH JI Int. J. Damage Mech. PD APR PY 2000 VL 9 IS 2 BP 130 EP 153 DI 10.1177/105678950000900202 PG 24 WC Materials Science, Multidisciplinary; Mechanics SC Materials Science; Mechanics GA 325ZR UT WOS:000087707700002 ER PT J AU George, DL Torczynski, JR Shollenberger, KA O'Hern, TJ Ceccio, SL AF George, DL Torczynski, JR Shollenberger, KA O'Hern, TJ Ceccio, SL TI Validation of electrical-impedance tomography for measurements of material distribution in two-phase flows SO INTERNATIONAL JOURNAL OF MULTIPHASE FLOW LA English DT Article DE electrical-impedance tomography; bubble column; gas volume fraction; multiphase flow ID CAPACITANCE SENSORS; 2-PHASE AB A series of studies is presented in which an electrical-impedance tomography (EIT) system is validated for two-phase flow measurements. The EIT system, developed at Sandia National Laboratories, is described along with the computer algorithm used for reconstructing phase volume fraction profiles. The algorithm is first tested using numerical data and experimental phantom measurements, with good results. The EIT system is then applied to solid-liquid and gas-liquid flows, and radial phase volume fraction profiles within a circular cross-section are determined. These profiles are compared to results from an established gamma-densitometry tomography (GDT) system. In the solid-liquid flows, the average solid volume fractions measured by EIT are in good agreement with nominal values. In the gas-liquid flows, average gas volume fractions and radial gas volume fraction profiles from GDT and EIT are also in good agreement. Published by Elsevier Science Ltd. C1 Sandia Natl Labs, Engn Sci Ctr, Albuquerque, NM 87185 USA. Univ Michigan, Dept Mech Engn & Appl Mech, Ann Arbor, MI 48109 USA. RP George, DL (reprint author), Sandia Natl Labs, Engn Sci Ctr, POB 5800, Albuquerque, NM 87185 USA. RI Chahine, Georges/A-2690-2011 OI Chahine, Georges/0000-0003-1610-3314 NR 26 TC 54 Z9 56 U1 3 U2 8 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0301-9322 J9 INT J MULTIPHAS FLOW JI Int. J. Multiph. Flow PD APR PY 2000 VL 26 IS 4 BP 549 EP 581 DI 10.1016/S0301-9322(99)00029-4 PG 33 WC Mechanics SC Mechanics GA 292HJ UT WOS:000085788300002 ER PT J AU Barth, RF Yang, WL Rotaru, JH Moeschberger, ML Boesel, CP Soloway, AH Joel, DD Nawrocky, MM Ono, K Goodman, JH AF Barth, RF Yang, WL Rotaru, JH Moeschberger, ML Boesel, CP Soloway, AH Joel, DD Nawrocky, MM Ono, K Goodman, JH TI Boron neutron capture therapy of brain tumors: Enhanced survival and cure following blood-brain barrier disruption and intracarotid injection of sodium borocaptate and boronophenylalanine SO INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS LA English DT Article; Proceedings Paper CT 4th Annual Meeting of the Society-for-Neuro-Oncology CY NOV 19-21, 1999 CL SCOTTSDALE, AZ SP Soc Neuro Oncol DE BNCT; boronophenylalanine; sodium borocaptate; BBB-D ID RAT-BRAIN; MALIGNANT GLIOMA; GENE-THERAPY; RADIATION; 9L; CHEMOTHERAPY; APOPTOSIS; DELIVERY; TISSUE; CELLS AB Purpose: Boronophenylalanine (BPA) and sodium borocaptate (Na(2)B(12)H(11)SH or BSH) have been used clinically for boron neutron capture therapy (BNCT) of high-grade gliomas. These drugs appear to concentrate in tumors by different mechanisms and may target different subpopulations of glioma cells. The purpose of the present study was to determine if the efficacy of BNCT could be further improved in F98-glioma-bearing rats by administering both boron compounds together and by improving their delivery by means of intracarotid (i.c.) injection with or without blood-brain barrier disruption (BBB-D), Methods and Materials: For biodistribution studies, 10(5) F98 glioma cells were implanted stereotactically into the brains of syngeneic Fischer rats. Eleven to 13 days later animals were injected intravenously (i.v.) with BPA at doses of either 250 or 500 mg/kg body weight (b.w.) in combination with BSH at doses of either 30 or 60 mg/kg b.w. or i.c. with or without BBB-D, which was accomplished by i.c. infusion of a hyperosmotic (25%) solution of mannitol. For BNCT studies, 10(3) F98 glioma cells were implanted intracerebrally, and 14 days later animals were transported to the Brookhaven National Laboratory (BNL), They received BPA (250 mg/kg b.w.) in combination with BSH (30 mg/kg b.w.) by i.v. or i.c. injection with or without BBB-D, and 2.5 hours later they were irradiated with a collimated beam of thermal neutrons at the BNL Medical Research Reactor. Results: The mean tumor boron concentration +/- standard deviation (SD) at 2.5 hours after i.c. injection of BPA (250 mg/kg b.w.) and BSH (30 mg/kg b.w.) was 56.3 +/- 37.8 mu g/g with BBB-D compared to 20.8 +/- 3.9 mu g/g without BBB-D and 11.2 +/- 1.8 mu g/g after i.v. injection. Doubling the dose of BPA and BSH produced a twofold increase in tumor boron concentrations, but also concomitant increases in normal brain and blood levels, which could have adverse effects, For this reason, the lower boron dose was selected for BNCT studies. The median survival time was 25 days for untreated control rats, 29 days for irradiated controls, 42 days for rats that received BPA and BSH i.v., 53 days following i.c, injection, and 72 days following i.c. injection + BBB-D with subsets of long-term survivors and/or cured animals in the latter two groups. No histopathologic evidence of residual tumor was seen in the brains of cured animals. Conclusions: The combination of BPA and BSH, administered i.c. with BBB-D, yielded a 25% cure rate for the heretofore incurable F98 rat glioma with minimal late radiation-induced brain damage. These results demonstrate that using a combination of boron agents and optimizing their delivery can dramatically improve the efficacy of BNCT in glioma-bearing rats. (C) 2000 Elsevier Science Inc. C1 Ohio State Univ, Dept Pathol, Columbus, OH 43210 USA. Ohio State Univ, Sch Publ Hlth, Div Epidemiol & Biometr, Columbus, OH 43210 USA. Ohio State Univ, Div Neurosurg, Columbus, OH 43210 USA. Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. Kyoto Univ, Res Inst, Radiat Oncol Res Lab, Kumatori, Osaka, Japan. RP Barth, RF (reprint author), Ohio State Univ, Dept Pathol, 165 Hamilton Hall,1645 Neil Ave, Columbus, OH 43210 USA. EM barth.1@osu.edu NR 60 TC 85 Z9 88 U1 2 U2 6 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0360-3016 J9 INT J RADIAT ONCOL JI Int. J. Radiat. Oncol. Biol. Phys. PD APR 1 PY 2000 VL 47 IS 1 BP 209 EP 218 DI 10.1016/S0360-3016(00)00421-1 PG 10 WC Oncology; Radiology, Nuclear Medicine & Medical Imaging SC Oncology; Radiology, Nuclear Medicine & Medical Imaging GA 303MW UT WOS:000086426500025 PM 10758326 ER PT J AU Reedy, ED AF Reedy, ED TI Connection between interface corner and interfacial fracture analyses of an adhesively-bonded butt joint SO INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES LA English DT Article DE adhesive; bond; corner; fracture; interface; joint; strength ID INTENSITY FACTOR PREDICTION; STRESS INTENSITIES; TENSILE-STRENGTH; SHARP NOTCHES; INITIATION; SINGULARITIES; TOUGHNESS; LAYER AB Interfacial crack growth in a tensile-loaded, adhesively-bonded butt joint with rigid adherends is analyzed. First, the asymptotic, small-scale cracking solution for a short interfacial crack originating at a sharp interface corner is presented, Then the asymptotic, steady-state solution for a long interfacial crack is discussed. These asymptotic results are compared with full finite element solutions of a butt joint containing a 0.001 to 10 bond thickness long interfacial crack. Finally, the applicability of both interface corner and interfacial fracture mechanics approaches to failure analysis is discussed. The small-scale cracking solution indicates that when one can apply an interface corner failure analysis, one can also apply an interfacial fracture mechanics approach with a suitably chosen inherent flaw. Although the two methods are equivalent, it should be emphasized that the inherent flaw and corresponding toughness may have limited physical significance. Published by Elsevier Science Ltd. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Reedy, ED (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 30 TC 34 Z9 36 U1 1 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0020-7683 J9 INT J SOLIDS STRUCT JI Int. J. Solids Struct. PD APR PY 2000 VL 37 IS 17 BP 2429 EP 2442 DI 10.1016/S0020-7683(99)00002-5 PG 14 WC Mechanics SC Mechanics GA 283FM UT WOS:000085265700004 ER PT J AU Wiegmann, A AF Wiegmann, A TI Analytic solutions of a multi-interface transmission problem and crack approximation SO INVERSE PROBLEMS LA English DT Article ID RECOVERY AB Analytic solutions to the Laplace equation in annulus and disc are combined with transmission conditions to find analytic solutions for transmission problems with multiple concentric circular interfaces. Coefficients are found rapidly by solving 2 x 2 linear systems for each interface. This makes them very suitable as test cases for inverse problem solvers. The special case of two very close interfaces is used to quantitatively test crack jump conditions which result from combining transmission conditions at the two interfaces into approximate conditions at a single interface. The quality of the approximation depends on whether the crack is resistive or conductive. C1 Univ Calif Berkeley, Dept Math, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Wiegmann, A (reprint author), Inst Techno & Wirtschaftsmath EV, D-67663 Kaiserslautern, Germany. NR 9 TC 0 Z9 0 U1 0 U2 2 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 APR PY 2000 VL 16 IS 2 BP 401 EP 411 DI 10.1088/0266-5611/16/2/309 PG 11 WC Mathematics, Applied; Physics, Mathematical SC Mathematics; Physics GA 314AB UT WOS:000087031000012 ER PT J AU Han, J Figiel, JJ Petersen, GA Myers, SM Crawford, MH Banas, MA AF Han, J Figiel, JJ Petersen, GA Myers, SM Crawford, MH Banas, MA TI Metal-organic vapor-phase epitaxial growth and characterization of quaternary AlGaInN SO JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS LA English DT Article; Proceedings Paper CT 1999 International Conference on Solid State Devices and Materials (SSDM 99) CY SEP 21-24, 1999 CL NIHON TOSHI CTR KAIKAN, TOKYO, JAPAN SP Japan Soc Appl Phys, IEEE, Electron Devices Soc HO NIHON TOSHI CTR KAIKAN DE AlGaInN; quaternary; MOVPE; quantum well; strain ID INGAN QUANTUM-WELLS; OPTICAL-PROPERTIES; GAN; DEPOSITION; PARAMETERS; EVOLUTION; ALLOYS; FILMS; ALINN AB We report the growth and characterization of quaternary AlGaInN. A combination of photoluminescence (PL), high-resolution X-ray diffraction (XRD), and Rutherford backscattering spectrometry (RBS) characterizations enables us to explore the contours of constant-PL peak energy and lattice parameter as functions of the quaternary compositions. The observation of room temperature PL emission at 351 nm (with 20%Al and S%In) renders initial evidence that the quaternary could be used to provide confinement for GaInN (and possibly GaN). AlGaInN/GaInN multiple quantum wells (MQWs) heterostructures have been grown; both XRD and PL measurement suggest the possibility of incorporating this quaternary into optoelectronic devices. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Han, J (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 23 TC 28 Z9 28 U1 0 U2 11 PU JAPAN J APPLIED PHYSICS PI MINATO-KU TOKYO PA DAINI TOYOKAIJI BLDG 24-8 SHINBASHI 4-CHOME, MINATO-KU TOKYO, 105, JAPAN SN 0021-4922 J9 JPN J APPL PHYS 1 JI Jpn. J. Appl. Phys. Part 1 - Regul. Pap. Short Notes Rev. Pap. PD APR PY 2000 VL 39 IS 4B BP 2372 EP 2375 DI 10.1143/JJAP.39.2372 PG 4 WC Physics, Applied SC Physics GA 347CG UT WOS:000088909300088 ER PT J AU Lowe, TC Valiev, RZ AF Lowe, TC Valiev, RZ TI Producing nanoscale microstructures through severe plastic deformation SO JOM-JOURNAL OF THE MINERALS METALS & MATERIALS SOCIETY LA English DT Editorial Material C1 Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. Ufa State Aviat Tech Univ, Inst Phys Adv Mat, Ufa, Russia. RP Los Alamos Natl Lab, Div Mat Sci & Technol, MS G754, Los Alamos, NM 87545 USA. EM tlowe@lanl.gov NR 11 TC 65 Z9 72 U1 2 U2 6 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086 USA SN 1047-4838 J9 JOM-J MIN MET MAT S JI JOM-J. Miner. Met. Mater. Soc. PD APR PY 2000 VL 52 IS 4 BP 27 EP 28 DI 10.1007/s11837-000-0127-8 PG 2 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing SC Materials Science; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing GA 302LL UT WOS:000086366500007 ER PT J AU Valiev, RZ Lowe, TC Mukherjee, AK AF Valiev, RZ Lowe, TC Mukherjee, AK TI Understanding the unique properties of SPD-induced microstructures SO JOM-JOURNAL OF THE MINERALS METALS & MATERIALS SOCIETY LA English DT Article ID SEVERE PLASTIC-DEFORMATION; NANOCRYSTALLINE NICKEL; GRAINED COPPER; SUPERPLASTICITY; DIFFUSION AB Refining microstructure by severe plastic deformation to a nanometer range changes fundamental properties, such as the Curie and Debye temperatures, and engineering properties of pragmatic significance, such as strength and ductility. These enhancements originate in the combination of very small grain sizes coupled with specific defect structures. Ongoing research is rapidly advancing the understanding of severe plastic deformation-induced microstructures, leading toward the commercialization of these materials. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. Ufa State Aviat Tech Univ, Inst Phys Adv Mat, Ufa, Russia. Univ Calif Davis, Dept Chem Engn & Mat Sci, Div Engn & Mat Sci, Davis, CA 95616 USA. RP Lowe, TC (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, MD G754, Los Alamos, NM 87545 USA. NR 30 TC 8 Z9 11 U1 2 U2 3 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 USA SN 1047-4838 J9 JOM-J MIN MET MAT S JI JOM-J. Miner. Met. Mater. Soc. PD APR PY 2000 VL 52 IS 4 BP 37 EP 40 DI 10.1007/s11837-000-0130-0 PG 4 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing SC Materials Science; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing GA 302LL UT WOS:000086366500010 ER PT J AU Lai, ACK Nazaroff, WW AF Lai, ACK Nazaroff, WW TI Modeling indoor particle deposition from turbulent flow onto smooth surfaces SO JOURNAL OF AEROSOL SCIENCE LA English DT Article ID BOUNDARY-LAYER; AIRBORNE PARTICLES; STIRRED TANK; PIPE-FLOW; WALL; AEROSOL; STATISTICS; SIMULATION; CALIFORNIA; TRANSPORT AB Particle deposition to indoor surfaces is frequently modeled by assuming that indoor air flow is homogeneously and isotropically turbulent. Existing formulations of such models, based on the seminal work of Corner and Pendlebury (1951, Proc. Phys. Sec. Lend. B64, 645), lack a thorough physical foundation. We apply the results of recent studies of near-surface turbulence to produce an analogous model for particle deposition onto indoor surfaces that remains practical to use yet has a stronger physical basis. The model accounts for the effects of Brownian and turbulent diffusion and gravitational settling. It predicts deposition to smooth surfaces as a function of particle size and density. The only required input parameters are enclosure geometry and friction velocity. Model equations are presented for enclosures with vertical and horizontal surfaces, and for spherical cavities. The model helps account for a previously unexplained experimental observation regarding the functional dependence of deposition velocity on particle size. Model predictions agree well with recently published experimental data for a spherical cavity (Cheng, Y. S., Aerosol Sci. Technol. 27, 131-146, (1997)). (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Ernest Orlando Lawrence Berkeley Natl Lab, Indoor Environm Dept, Environm Energy Technol Div, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Civil & Environm Engn, Berkeley, CA 94720 USA. RP Nazaroff, WW (reprint author), Ernest Orlando Lawrence Berkeley Natl Lab, Indoor Environm Dept, Environm Energy Technol Div, Berkeley, CA 94720 USA. RI Lai, Alvin/G-8409-2011; Nazaroff, William/C-4106-2008 OI Lai, Alvin/0000-0002-6202-1988; Nazaroff, William/0000-0001-5645-3357 NR 40 TC 289 Z9 296 U1 4 U2 69 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0021-8502 J9 J AEROSOL SCI JI J. Aerosol. Sci. PD APR PY 2000 VL 31 IS 4 BP 463 EP 476 PG 14 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 293AR UT WOS:000085829800006 ER PT J AU De Belie, N Sonck, B Braam, CR Lenehan, JJ Svennerstedt, B Richardson, M AF De Belie, N Sonck, B Braam, CR Lenehan, JJ Svennerstedt, B Richardson, M TI Durability of building materials and components in the agricultural environment, part II: Metal structures SO JOURNAL OF AGRICULTURAL ENGINEERING RESEARCH LA English DT Review ID SULFATE-REDUCING BACTERIA; STEEL CORROSION; MILD-STEEL; ANIMAL BUILDINGS; PRODUCTS; BIOFILM; OXIDES; IRON AB Metals in agricultural structures are often subjected to adverse environmental conditions resulting in high corrosion rates (up to 200 mu m/yr). The different factors enhancing metal corrosion in farm buildings include high humidity and temperature, high concentrations of aggressive gases, acids, and salts (from silage and feed residues, cleaning agents, manure, fertilizers, preservatives), mechanical destruction and bacteria causing microbially induced corrosion. The importance of microbially induced corrosion is not yet clarified and a reduction in corrosion by biofilms on metals has also been reported. Corrosion products found in animal houses are similar to those resulting from classic corrosion mechanisms, which may lead to the conclusion that the fundamental mechanisms of metal corrosion in animal buildings are similar to the classic ones. Different methods to detect, measure and predict corrosion are described. The economic losses by corrosion in agriculture are evaluated. By corrosion prevention, a reasonable amount of expense can be saved. Prevention includes: (1) the choice of corrosion resistant materials such as stainless steel or non-metallic materials; (2) designing against corrosion; (3) control of the aggressive environment; and (4) application of coatings. When protective coatings are used, such as zinc layers and painting systems, surface preparation of the metal is of the utmost importance. Zinc layers should be thick enough (> 50 mu m), and zinc-coated steel should be protected in areas of extreme aggressiveness, such as fittings at floor level. Reports about the durability of different painting systems in agricultural structures are reviewed. The development of new environmentally friendly products is discussed. Guidelines for maintenance of previously painted steelwork are formulated. (C) 2000 Silsoe Research Institute. C1 Katholieke Univ Leuven, Dept Agroengn & Econ, Louvain, Belgium. Agr Res Ctr, Dept Mechanisat Labour Bldg Anim Welf & Environm, Ghent, Belgium. Delft Univ Technol, Fac Civil Engn, Concrete Struct Grp, Delft, Netherlands. TEAGASC, Grange Res Ctr, Agr & Food Dev Author, Dunsany, Meath, Ireland. Swedish Univ Agr Sci, Dept Agr Biosyst & Technol, Alnarp, Sweden. Univ Coll Dublin, Dept Civil Engn, Dublin 2, Ireland. RP De Belie, N (reprint author), Katholieke Univ Leuven, Dept Agroengn & Econ, Louvain, Belgium. NR 97 TC 10 Z9 11 U1 1 U2 10 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0021-8634 J9 J AGR ENG RES JI J. Agr. Eng. Res. PD APR PY 2000 VL 75 IS 4 BP 333 EP 347 DI 10.1006/jaer.1999.0521 PG 15 WC Agricultural Engineering SC Agriculture GA 304FV UT WOS:000086473600001 ER PT J AU Phillips, WC Stanton, M Stewart, A Qian, H Ingersoll, C Sweet, RM AF Phillips, WC Stanton, M Stewart, A Qian, H Ingersoll, C Sweet, RM TI Multiple CCD detector for macromolecular x-ray crystallography SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article ID AREA DETECTOR; RIBOSOMAL-SUBUNIT; ANGSTROM-RESOLUTION; CRYSTAL-STRUCTURE; DIFFRACTION DATA; PROTEIN; DOMAIN; DESIGN; ALPHA; MAP AB A charge-coupled device (CCD)-based detector designed for macromolecular crystallography is described. The detector has an area of 200 x 200 mm, a readout time of 1.6 s, and total noise equivalent to approximately three 12 keV X-ray photons per pixel. The detector is constructed from a 2 x 2 array of four identical units, each unit consisting of a 4.1:1 demagnifying fiber-optic taper bonded to a 1 k x 1 k, 24 mu m pixel, CCD sensor. Each CCD is read out in parallel though four channels and digitized to 16 bits. A Gd2O2S phosphor X-ray-to-light converter bonded to an aluminized-plastic film is held in contact with the input surfaces of the fiber-optic tapers with an air pillow. The full width at half-maximum (FWHM) of the point response function is 120 mu m, the response is linear to better than 1% over the entire range of intensity from background to nearly full well, the gain is 3.4 e per 8 keV incident X-ray photon, the noise is 12.6 e per pixel for a 10 s integration time, the modulation transfer function (MTF) is 0.35 at 5 line pairs (1p) mm(-1) (the Nyquest frequency), and the measured detective quantum efficiency (DQE) is 0.74 for relatively strong Bragg peaks. Data collected from crystallographic studies with synchrotron radiation are presented. In an anomalous difference Patterson map for a data set collected in 40 min on a monoclinic myoglobin crystal, the magnitude of the Fe-Fe peaks is 18 times the standard uncertainty of the map. (C) 2000 International Union of Crystallography Printed in Great Britain - all rights reserved. C1 Brandeis Univ, Rosenstiel Basic Med Sci Res Ctr, Waltham, MA 02454 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Phillips, WC (reprint author), Brandeis Univ, Rosenstiel Basic Med Sci Res Ctr, Waltham, MA 02454 USA. NR 24 TC 18 Z9 19 U1 0 U2 0 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 APR PY 2000 VL 33 BP 243 EP 251 DI 10.1107/S0021889899015666 PN 2 PG 9 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 308YK UT WOS:000086740300007 ER PT J AU Wang, DQ Wang, XL Robertson, JL Hubbard, CR AF Wang, DQ Wang, XL Robertson, JL Hubbard, CR TI Modeling radial collimators for use in stress and texture measurements with neutron diffraction SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article AB Radial collimators have been recently introduced to define the sampling volume during neutron diffraction stress and texture mapping experiments. This paper presents both analytical and Monte Carlo numerical models for the calculation of the spatial distribution of neutron transmission through a radial collimator. It is shown that the effective size of the scattered neutron beam as seen by detectors behind the collimator is quite sensitive to the collimator length and the number of blades. For a given radius of a collimator, the effective beam width increases sharply as the length is shortened. Due to the finite blade thickness, the center of gravity of the sampling volume is shifted away from the collimator. In contrast, attenuation of the neutron beam by the sample brings the center of gravity of the sampling volume closer to the collimator. (C) 2000 Internatlonat Union of Crystallography Printed in Great Britain - all rights reserved. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Wang, DQ (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. RI Wang, Xun-Li/C-9636-2010 OI Wang, Xun-Li/0000-0003-4060-8777 NR 6 TC 11 Z9 11 U1 0 U2 5 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 APR PY 2000 VL 33 BP 334 EP 337 DI 10.1107/S0021889800000856 PN 2 PG 4 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 308YK UT WOS:000086740300019 ER PT J AU Glucksman, AM Skipper, HD Brigmon, RL Santo Domingo, JW AF Glucksman, AM Skipper, HD Brigmon, RL Santo Domingo, JW TI Use of the MIDI-FAME technique to characterize groundwater communities SO JOURNAL OF APPLIED MICROBIOLOGY LA English DT Article ID MICROBIAL COMMUNITIES; BACTERIA; TOLERANCE; BIOMASS; ECOLOGY AB Fatty acid methyl ester (FAME) profiles were identified directly from groundwater microbial communities concentrated on and extracted with polycarbonate filters. The sensitivity of this direct extraction method was determined using pure cultures of Acinetobacter junii, Pseudomonas putida and Stenotrophomonas maltophilia. A minimum concentration of 10(7) cells filter(-1) was required to identify the predominant fatty acids from each culture. However, at least 3.7 x 10(9) cells filter(-1) were required to obtain fatty acid profiles that matched the signature profiles for pure cultures in a commercial database. While several saturated fatty acids (i.e. 14 : 0, 16 : 0, 18 : 0) were extracted from the polycarbonate filters, they were readily subtracted from microbial fatty acid profiles and did not interfere with the characterization of pure cultures or environmental samples. For the environmental samples, 3 l of groundwater from the Savannah River Site, Aiken, SC, (USA) contained sufficient biomass for direct extraction. A comparative analysis of FAME groundwater profiles demonstrated a qualitative difference among communities sampled from spatially discrete locations, while a groundwater well that was sampled at two time points showed strong similarities over time. Concentration of microbial biomass on polycarbonate filters coupled with the MIDI-FAME extraction of both biomass and filter was a useful technique to characterize microbial communities from groundwater. C1 Westinghouse Savannah River Co, Savannah River Technol Ctr, Environm Biotechnol Sect, Aiken, SC 29808 USA. US EPA, NERC MCEARD, Cincinnati, OH 45268 USA. Clemson Univ, Dept Agron, Clemson, SC USA. CSRA Analyt Labs Inc, Augusta, GA USA. RP Brigmon, RL (reprint author), Westinghouse Savannah River Co, Savannah River Technol Ctr, Environm Biotechnol Sect, Bldg 704-8T TNX, Aiken, SC 29808 USA. NR 22 TC 21 Z9 25 U1 0 U2 6 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 1364-5072 J9 J APPL MICROBIOL JI J. Appl. Microbiol. PD APR PY 2000 VL 88 IS 4 BP 711 EP 719 DI 10.1046/j.1365-2672.2000.01058.x PG 9 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 300WK UT WOS:000086276600019 PM 10792531 ER PT J AU Nelson, AJ Danailov, M Gregoratti, L Marsi, M Kiskinova, M AF Nelson, AJ Danailov, M Gregoratti, L Marsi, M Kiskinova, M TI Scanning photoelectron microscopy study of the laser-induced transformations of polycrystalline CdTe films SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ESCA MICROSCOPY; PHOTOEMISSION; ELETTRA; IRRADIATION; STATES AB We have used pulsed-laser treatment to provide highly localized chemical reactions in the near-surface region of polycrystalline CdTe thin films. Using scanning photoelectron microscopy, the lateral changes in the composition and morphology of the films as a function of the irradiation conditions and of the distance from the center of the laser beam were characterized. Results show that the films undergo thermal-induced heterogeneity in the morphology and in the lateral distribution of the elements and chemical phases due to local melting and dissociation of the film. This transformation leads to a local increase of the conductivity and enrichment with elemental Te. (C) 2000 American Institute of Physics. [S0021-8979(00)02107-1]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Int Ctr Theoret Phys, Laser Lab, I-34100 Trieste, Italy. Sincrotrone Trieste, I-34012 Trieste, Italy. RP Nelson, AJ (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. OI Danailov, Miltcho/0000-0002-1888-1331 NR 20 TC 14 Z9 14 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 1 PY 2000 VL 87 IS 7 BP 3520 EP 3525 DI 10.1063/1.372375 PG 6 WC Physics, Applied SC Physics GA 293WN UT WOS:000085878100053 ER PT J AU Stemmer, S Bai, GR Browning, ND Streiffer, SK AF Stemmer, S Bai, GR Browning, ND Streiffer, SK TI Microstructure of epitaxial Pb(Mg1/3Nb2/3)O-3-PbTiO3 thin films grown by metalorganic chemical vapor deposition SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID LEAD MAGNESIUM NIOBATE; PEROVSKITE; BEHAVIOR; CRYSTALS AB Epitaxial, perovskite Pb(Mg1/3Nb2/3)O-3-PbTiO3 films were grown by metalorganic chemical vapor deposition under various deposition conditions and characterized by x-ray diffraction and transmission electron microscopy. Pyrochlore free films were obtained under all deposition conditions used in this study. Magnesium-rich growth conditions lead to the formation of a Mg-rich impurity phase in the films, embedded as coherent lamellae parallel to the growth direction. Depending on the growth conditions, a wide variation in the stoichiometry and volume fraction of this impurity phase was found between samples, whereas morphology and crystal structure were found to be very similar. (C) 2000 American Institute of Physics. [S0021-8979(00)01607-8]. C1 Univ Illinois, Dept Phys, Chicago, IL 60607 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Stemmer, S (reprint author), Rice Univ, Dept Mech Engn & Mat Sci, MS 321,6100 Main St, Houston, TX 77005 USA. RI Streiffer, Stephen/A-1756-2009; Stemmer, Susanne/H-6555-2011; OI Stemmer, Susanne/0000-0002-3142-4696; Browning, Nigel/0000-0003-0491-251X NR 20 TC 19 Z9 19 U1 3 U2 6 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 1 PY 2000 VL 87 IS 7 BP 3526 EP 3531 DI 10.1063/1.372376 PG 6 WC Physics, Applied SC Physics GA 293WN UT WOS:000085878100054 ER PT J AU Toet, D Smith, PM Sigmon, TW Thompson, MO AF Toet, D Smith, PM Sigmon, TW Thompson, MO TI Experimental and numerical investigations of a hydrogen-assisted laser-induced materials transfer procedure SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID EXCIMER-LASER; AMORPHOUS-SILICON; METAL-DEPOSITION; FILMS; DYNAMICS AB We present investigations of the mechanisms of a laser-induced transfer technique, which can be used for the spatially selective deposition of materials such as Si. This transfer is effected by irradiating the backside of a hydrogenated amorphous silicon film, deposited on a transparent substrate with an excimer laser pulse. The resulting release and accumulation of hydrogen at the film/substrate interface propels the silicon onto an adjacent receptor wafer. Time-resolved infrared transmission measurements indicate that the amorphous film is melted by the laser pulse and breaks into droplets during ejection. These droplets travel towards the receptor substrate and coalesce upon arrival. The transfer velocity increases as a function of fluence, the rate of increase dropping noticeably around the full melt threshold of the film. At this fluence, the transfer velocity reaches values of around 1000 m/s for typical films. Atomic force microscopy reveals that films transferred below the full melt threshold only partially cover the receptor substrate, while uniform, well-adhering films, which can be smoothed by subsequent laser irradiation, are obtained above it. Transfer of hydrogen-free Si films, on the other hand, does not occur until much higher fluences. The dynamics of the process have been simulated using a semiquantitative numerical model. In this model, hydrogen released from the melt front is instantaneously accumulated at the interface with an initial kinetic energy given by the melting temperature of Si and the enthalpy of solution. The resulting pressure accelerates the Si film, the dynamics of which are modeled using Newtonian mechanics, and the gas cools adiabatically as its kinetic energy is converted to the film's momentum. The results of the calculations are in good agreement with the experimental data. (C) 2000 American Institute of Physics. [S0021-8979(00)07904-4]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Cornell Univ, Dept Mat Sci & Engn, Ithaca, NY 14853 USA. RP Toet, D (reprint author), Univ Calif Lawrence Livermore Natl Lab, L-271,7000 East Ave, Livermore, CA 94550 USA. OI Thompson, Michael/0000-0002-4933-009X NR 24 TC 12 Z9 12 U1 1 U2 6 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 1 PY 2000 VL 87 IS 7 BP 3537 EP 3546 DI 10.1063/1.372378 PG 10 WC Physics, Applied SC Physics GA 293WN UT WOS:000085878100056 ER PT J AU Liang, L Feng, XD Martin, PFC Peurrung, LM AF Liang, L Feng, XD Martin, PFC Peurrung, LM TI Temperature-sensitive switch from composite poly(N-isopropylacrylamide) sponge gels SO JOURNAL OF APPLIED POLYMER SCIENCE LA English DT Article DE temperature-sensitive polymers; crosslinking polymer gels; poly(N-isopropylacrylamide); polymer sensors ID N-ISOPROPYLACRYLAMIDE; MEMBRANES; HYDROGELS; RELEASE AB Thermally sensitive polymers change their properties with a change in environmental temperature in a predictable and pronounced way. These changes can be expected in drug delivery systems, solute separation, enzyme immobilization, energy-transducer processes, and photosensitive materials. We have demonstrated a thermal-sensitive switch module, which is capable of converting thermal into mechanical energy. We employed this module in the control of liquid transfer. The thermally sensitive switch was prepared by crosslinking poly(N-isopropylacrylamide) (PNIPAAm) gel inside the pores of a sponge to generate the composite PNIPAAm/sponge gel. This gel, contained in a polypropylene tube, was inserted into a thermoelectric module equipped with a fine temperature controller. As the water flux through the composite gel changes from 0 to 6.6 x 10(2) L m(-2) h, with a temperature change from 23 to 40 degrees C, we can reversibly turn on and off the thermally sensitive switch. (C) 2000 John Wiley & Sons, Inc. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Liang, L (reprint author), Pacific NW Natl Lab, 902 Battelle Blvd,POB 999,Mail Stop K6-24, Richland, WA 99352 USA. NR 21 TC 24 Z9 24 U1 1 U2 8 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0021-8995 J9 J APPL POLYM SCI JI J. Appl. Polym. Sci. PD APR 1 PY 2000 VL 75 IS 14 BP 1735 EP 1739 DI 10.1002/(SICI)1097-4628(20000401)75:14<1735::AID-APP7>3.0.CO;2-R PG 5 WC Polymer Science SC Polymer Science GA 278TY UT WOS:000085006100007 ER PT J AU Stevenson, BA Horwitz, JL Creel, B Elliott, HA Comfort, RH Moore, TE Craven, PD Su, YJ AF Stevenson, BA Horwitz, JL Creel, B Elliott, HA Comfort, RH Moore, TE Craven, PD Su, YJ TI Relationship of O+ field-aligned flows and densities to convection speed in the polar cap at 5000 km altitude SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article ID CLEFT ION FOUNTAIN; WIND; DYNAMICS; REGION AB Measurements of thermal O+ ion number fluxes, densities, field-aligned velocities, and convection speeds from the Thermal Ion Dynamics Experiment (TIDE) on POLAR obtained near 5000 km altitude over the Southern hemisphere are examined. We find that the O+ parallel velocities, densities, and number fluxes are strongly related to the convection speeds. The polar cap densities decrease rapidly with convection speed, with a linear least square fit formula to bin averaged data giving the relationship log(NO+) = -0.33 * V-conv + 0.07, with a correlation coefficient of r = -0.96, The parallel bulk flow velocities are on average, slightly downward (0-2 km/s) for V-conv < 2.5 km/s, but tend to be upward (0-4 km/s) for average V-conv > 2 5 km/s. We also find that the downward number flux is strongly related to convection speed by log(Flux) = -0.54V(conv) + 5.14, with a correlation coefficient of r = -0.98, We interpret these relationships in terms of the Cleft Ion Fountain paradigm. The density decline with convection speed may result from increased spreading and resulting dilution from the restricted cleft source over the polar cap area with convection speed. The parallel velocities tend to be downward for low convection speeds because at such speeds, the ions fall earthward at shorter anti-sunward distances into the polar cap. At the higher convection speeds, the initially-upward flows are transported further into the polar cap and thus occupy a larger area of the polar cap. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Alabama, Ctr Space Plasma & Aeronom Res, Huntsville, AL 35899 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. RP Stevenson, BA (reprint author), Univ Alabama, Ctr Space Plasma & Aeronom Res, S121-Tech Hall, Huntsville, AL 35899 USA. RI Moore, Thomas/D-4675-2012; OI Moore, Thomas/0000-0002-3150-1137; Stevenson, Benjamin/0000-0001-9918-1240 NR 18 TC 4 Z9 4 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD APR PY 2000 VL 62 IS 6 BP 495 EP 503 DI 10.1016/S1364-6826(00)00030-4 PG 9 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 325KW UT WOS:000087675600009 ER PT J AU Mourant, JR Canpolat, M Brocker, C Esponda-Ramos, O Johnson, TM Matanock, A Stetter, K Freyer, JP AF Mourant, JR Canpolat, M Brocker, C Esponda-Ramos, O Johnson, TM Matanock, A Stetter, K Freyer, JP TI Light scattering from cells: the contribution of the nucleus and the effects of proliferative status SO JOURNAL OF BIOMEDICAL OPTICS LA English DT Article DE optical pathology; tissue diagnostics; DNA content; cancer; cell cycle analysis ID TISSUE DIAGNOSTICS; PROGNOSTIC FACTOR; FLOW-CYTOMETRY; DNA CONTENT; SPECTROSCOPY; CANCER; PLOIDY AB As part of our ongoing efforts to understand the fundamental nature of light scattering from cells and tissues, we present data on elastic light scattering from isolated mammalian tumor cells and nuclei. The contribution of scattering from internal structures and in particular from the nuclei was compared to scattering from whole cells. Roughly 55% of the elastic light scattering at high-angles (>40 degrees) comes from intracellular structures. An upper limit of 40% on the fractional contribution of nuclei to scattering from cells in tissue was determined. Using cell suspensions isolated from monolayer cultures at different stages of growth, we have also found that scattering at angles greater than about 110 degrees was correlated with the DNA content of the cells. Based on model calculations and the relative size difference of nuclei from cells in different stages of growth, we argue that this difference in scattering results from changes in the internal structures of the nucleus. This interpretation is consistent with our estimate of 0.2 mu m as the mean size of the scattering centers in cells. Additionally, we find that while scattering from the nucleus accounts for a majority of internal scattering, a significant portion must result from scattering off of cytoplasmic structures such as mitochondria. (C) 2000 Society of Photo-Optical instrumentation Engineers. [S1083-3668(00)00202-1]. C1 Univ Calif Los Alamos Natl Lab, Biosci Div, Los Alamos, NM 87545 USA. RP Mourant, JR (reprint author), Univ Calif Los Alamos Natl Lab, Biosci Div, MS E535, Los Alamos, NM 87545 USA. FU NCI NIH HHS [R01 CA071898, CA-71898]; NCRR NIH HHS [RR-01315]; NIEHS NIH HHS [ES-07845] NR 26 TC 155 Z9 155 U1 6 U2 14 PU SPIE-INT SOCIETY OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, BELLINGHAM, WA 98225 USA SN 1083-3668 J9 J BIOMED OPT JI J. Biomed. Opt. PD APR PY 2000 VL 5 IS 2 BP 131 EP 137 DI 10.1117/1.429979 PG 7 WC Biochemical Research Methods; Optics; Radiology, Nuclear Medicine & Medical Imaging SC Biochemistry & Molecular Biology; Optics; Radiology, Nuclear Medicine & Medical Imaging GA 325AU UT WOS:000087654800003 PM 10938776 ER PT J AU Bigio, IJ Bown, SG Briggs, G Kelley, C Lakhani, S Pickard, D Ripley, PM Rose, IG Saunders, C AF Bigio, IJ Bown, SG Briggs, G Kelley, C Lakhani, S Pickard, D Ripley, PM Rose, IG Saunders, C TI Diagnosis of breast cancer using elastic-scattering spectroscopy: preliminary clinical results SO JOURNAL OF BIOMEDICAL OPTICS LA English DT Article DE elastic-scattering spectroscopy; diffuse reflectance; tissue spectroscopy; optical diagnosis; optical biopsy ID LIGHT-SCATTERING; TISSUE; REFLECTANCE; BIOPSY AB We report on the first stages of a clinical study designed to test elastic-scattering spectroscopy, mediated by fiberoptic probes, for three specific clinical applications in breast-tissue diagnosis: (1) a transdermal-needle (interstitial) measurement for instant diagnosis with minimal invasiveness similar to fine-needle aspiration but with sensitivity to a larger tissue volume, (2) a hand-held diagnostic probe for use in assessing tumor/resection margins during open surgery, and (3) use of the same probe for real-time assessment of the "sentinel" node during surgery to determine the presence or absence of tumor (metastatic). Preliminary results from in vivo measurements on 31 women are encouraging. Optical spectra were measured on 72 histology sites in breast tissue, and 54 histology sites in sentinel nodes. Two different artificial intelligence methods of spectral classification were studied. Artificial neural networks yielded sensitivities of 69% and 58%, and specificities of 85% and 93%, for breast tissue and sentinel nodes, respectively. Hierarchical cluster analysis yielded sensitivities of 67% and 91%, and specificities of 79% and 77%, for breast tissue and sentinel nodes, respectively. These values are expected to improve as the data sets continue to grow and more sophisticated data preprocessing is employed. The study will enroll up to 400 patients over the next two years. (C) 2000 society of Photo-Optical instrumentation Engineers. [S1083-3668(00)00302-6]. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. UCL, Natl Med Laser Ctr, London W1P 7LD, England. Royal Free & Univ Coll Med Sch, Dept Histopathol, London W1P 7LD, England. UCL, Natl Med Laser Ctr, London W1P 7LD, England. RP Bigio, IJ (reprint author), Los Alamos Natl Lab, MS-E535, Los Alamos, NM 87545 USA. EM ijb@LANL.gov RI Bown, Stephen/C-5713-2009; Saunders, Christobel/H-5779-2014; OI Saunders, Christobel/0000-0003-2281-9829; Bigio, Irving/0000-0003-4168-1466 NR 21 TC 200 Z9 200 U1 3 U2 19 PU SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 1083-3668 J9 J BIOMED OPT JI J. Biomed. Opt. PD APR PY 2000 VL 5 IS 2 BP 221 EP 228 DI 10.1117/1.429990 PG 8 WC Biochemical Research Methods; Optics; Radiology, Nuclear Medicine & Medical Imaging SC Biochemistry & Molecular Biology; Optics; Radiology, Nuclear Medicine & Medical Imaging GA 325AU UT WOS:000087654800014 PM 10938787 ER PT J AU Kinney, JH Haupt, DL Ryaby, JT Lane, NE AF Kinney, JH Haupt, DL Ryaby, JT Lane, NE TI Relating trabecular bone architecture to the elastic properties of intact vertebra in the OVX rat model. SO JOURNAL OF BONE AND MINERAL RESEARCH LA English DT Meeting Abstract C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. OrthoLog, Tempe, AZ USA. Univ Calif San Francisco, San Francisco, CA 94143 USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU AMER SOC BONE & MINERAL RES PI DURHAM PA PO BOX 2759, DURHAM, NC 27715-2759 USA SN 0884-0431 J9 J BONE MINER RES JI J. Bone Miner. Res. PD APR PY 2000 VL 15 IS 4 MA 20 BP 799 EP 799 PG 1 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA 296VM UT WOS:000086047500040 ER PT J AU Coronado, EA Batista, VS Miller, WH AF Coronado, EA Batista, VS Miller, WH TI Nonadiabatic photodissociation dynamics of ICN in the (A)over-tilde continuum: A semiclassical initial value representation study SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID CHANNEL SCATTERING CALCULATIONS; DEPENDENT QUANTUM-MECHANICS; MOLECULAR-DYNAMICS; WAVE-PACKET; GEMINATE RECOMBINATION; CLASSICAL ANALOG; TRIATOMIC PHOTODISSOCIATION; ROTATIONAL DISTRIBUTIONS; ELECTRONIC-TRANSITIONS; PHOTO-DISSOCIATION AB In this paper we investigate the nonadiabatic photodissociation dynamics of ICN in the A continuum, using a semiclassical initial value representation method which is able to describe electronically nonadiabatic processes through the quantization of the classical electron-nuclear model Hamiltonian of Meyer and Miller [J. Chem. Phys. 70, 3214 (1979)]. We explore the capabilities of this semiclassical technique as applied to studying the ICN absorption spectrum, and the CN rotational distribution, through direct comparison of our semiclassical results with experimental data, and with full quantum mechanical calculations. We find that the Meyer-Miller Hamiltonian, quantized according to the semiclassical prescription, describes the ICN photodissociation dynamics in excellent agreement with full-quantum mechanical calculations. (C) 2000 American Institute of Physics. [S0021-9606(00)01113-2]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Coronado, EA (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. OI Coronado, Eduardo A./0000-0002-2251-1501 NR 77 TC 59 Z9 59 U1 1 U2 9 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 APR 1 PY 2000 VL 112 IS 13 BP 5566 EP 5575 DI 10.1063/1.481130 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 294FZ UT WOS:000085902300007 ER PT J AU Feller, D Sordo, JA AF Feller, D Sordo, JA TI A CCSDT study of the effects of higher order correlation on spectroscopic constants. I. First row diatomic hydrides SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MOLECULAR WAVE-FUNCTIONS; CONFIGURATION-INTERACTION CALCULATIONS; BENCHMARK CALCULATIONS; SYSTEMATIC SEQUENCES; ELECTRON-AFFINITIES; BASIS-SETS; GAUSSIAN-2; ENERGIES; LIMIT; WATER AB Spectroscopic constants have been determined for 13 first row diatomic hydrides using coupled cluster theory with explicit inclusion of (iterative) triple excitations (CCSDT). Comparison of the predicted dissociation energies, bond lengths, harmonic frequencies, and anharmonicities was made with experiment and other high-level theoretical treatments. These include complete active space configuration interaction wave functions, coupled cluster theory with perturbative triples [CCSD(T)], and new benchmark full configuration interaction calculations. Excellent overall agreement with experiment was found, even without correcting for small changes due to core/valence and relativistic effects. The intrinsic CCSDT error with respect to experiment for each molecule and property was estimated by extrapolating to the complete basis set limit. Among the various properties examined in this study, no significant differences were found between CCSD(T) and CCSDT. In light of the substantial increase in computational cost associated with the latter method, there appears to be little justification for selecting it over CCSD(T) in studies of first row hydrides. Preliminary results for first row diatomics, e.g., N-2, suggest that the impact of CCSDT will increase with the number of electrons. (C) 2000 American Institute of Physics. [S0021-9606(00)31513-6]. C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Univ Oviedo, Fac Quim, Dept Quim Fis, Lab Quim Computac, Oviedo 33006, Spain. RP Pacific NW Lab, Environm Mol Sci Lab, MS K8-91,POB 999, Richland, WA 99352 USA. NR 40 TC 93 Z9 94 U1 1 U2 8 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 APR 1 PY 2000 VL 112 IS 13 BP 5604 EP 5610 DI 10.1063/1.481135 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 294FZ UT WOS:000085902300011 ER PT J AU Fedorov, DG Gordon, MS AF Fedorov, DG Gordon, MS TI A study of the relative importance of one and two-electron contributions to spin-orbit coupling SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID GAUSSIAN-BASIS SETS; CORRELATED MOLECULAR CALCULATIONS; EFFECTIVE CORE POTENTIALS; MAIN-GROUP ELEMENTS; VALENCE BASIS-SETS; WAVE-FUNCTIONS; MEAN-FIELD; SI; GE; SN AB The existing methods to estimate the magnitude of spin-orbit coupling for arbitrary molecules and multiconfigurational wave functions are reviewed. The form-factor method is extended from the original singlet-triplet formulation into arbitrary multiplicities. A simplified version of the mean-field method (the partial two-electron method, P2E) is formulated and tested versus the full two-electron operator on a set of representative molecules. The change of the one and two-electron spin-orbit coupling down the Periodic Table is investigated, and it is shown that the computationally much less demanding P2E method has an accuracy comparable to that of the full two-electron method. (C) 2000 American Institute of Physics. [S0021-9606(00)30107-6]. C1 Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Fedorov, DG (reprint author), Iowa State Univ, Dept Chem, Ames, IA 50011 USA. NR 47 TC 121 Z9 122 U1 1 U2 16 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 1 PY 2000 VL 112 IS 13 BP 5611 EP 5623 DI 10.1063/1.481136 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 294FZ UT WOS:000085902300012 ER PT J AU Nicklass, A Peterson, KA Berning, A Werner, HJ Knowles, PJ AF Nicklass, A Peterson, KA Berning, A Werner, HJ Knowles, PJ TI Convergence of Breit-Pauli spin-orbit matrix elements with basis set size and configuration interaction space: The halogen atoms F, Cl, and Br SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID GAUSSIAN-BASIS SETS; CORRELATED MOLECULAR CALCULATIONS; EFFECTIVE CORE POTENTIALS; ELECTRONIC-STRUCTURE; WAVE-FUNCTIONS; EFFICIENT; ENERGY; 1ST-ROW; STATES; PSEUDOPOTENTIALS AB Systematic sequences of basis sets are used to calculate the spin-orbit splittings of the halogen atoms F, Cl, and Br in the framework of first-order perturbation theory with the Breit-Pauli operator and internally contracted configuration interaction wave functions. The effects of both higher angular momentum functions and the presence of tight functions are studied. By systematically converging the one-particle basis set, an unambiguous evaluation of the effects of correlating different numbers of electrons in the Cl treatment is carried out. Correlation of the 2p-electrons in chlorine increases the spin-orbit splitting by similar to 80 cm(-1), while in bromine we observe incremental increases of 130, 145, and 93 cm(-1), when adding the 3d, 3p, and 2p electrons to the set of explicitly correlated electrons, respectively. For fluorine and chlorine the final basis set limit, all-electrons correlated results match the experimentally observed spin-orbit splittings to within similar to 5 cm(-1), while for bromine the Breit-Pauli operator underestimates the splitting by about 100 cm(-1). More extensive treatment of electron correlation results in only a slight lowering of the spin-orbit matrix elements. Thus, the discrepancy for bromine is proposed to arise from the nonrelativistic character of the underlying wave function. (C) 2000 American Institute of Physics. [S0021-9606(00)31413-1]. C1 Washington State Univ, Dept Chem, Richland, WA 99352 USA. Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Univ Stuttgart, Inst Theoret Chem, D-70550 Stuttgart, Germany. Univ Birmingham, Sch Chem, Birmingham B15 2TT, W Midlands, England. RP Peterson, KA (reprint author), Washington State Univ, Dept Chem, Richland, WA 99352 USA. RI Knowles, Peter/G-2985-2010; Werner, Hans-Joachim/G-9509-2011 OI Knowles, Peter/0000-0003-4657-6331; Werner, Hans-Joachim/0000-0002-0435-539X NR 53 TC 38 Z9 38 U1 1 U2 5 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 1 PY 2000 VL 112 IS 13 BP 5624 EP 5632 DI 10.1063/1.481137 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 294FZ UT WOS:000085902300013 ER PT J AU Kendrick, BK AF Kendrick, BK TI Geometric phase effects in the H+D-2 -> HD+D reaction SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID POTENTIAL-ENERGY SURFACE; INTEGRAL CROSS-SECTIONS; STATE TRANSITION-PROBABILITIES; LOG-DERIVATIVE METHOD; CONICAL INTERSECTION; REACTION DYNAMICS; IDENTICAL NUCLEI; H+O-2 SCATTERING; H+D-2 REACTION; BOUND-STATES AB The general vector potential (gauge theory) approach for including geometric phase effects in accurate three-dimensional quantum scattering calculations in symmetrized hyperspherical coordinates is applied to the H + D-2(v,j) --> HD(v',j') + D reaction at 126 values of total energy in the range 0.4-2.4 eV. State-to-state reaction probabilities, integral, and differential cross sections are computed using both the Boothroyd-Keogh-Martin-Peterson (BKMP2) and the Liu-Siegbahn-Truhlar-Horowitz potential energy surfaces for the first six values of total angular momentum (J less than or equal to 5). Calculations are performed on each surface both with and without the geometric phase. Due to symmetry, the effects of the geometric phase are shown to cancel out when contributions from even and odd values of J are added together for both the integral and differential cross sections, at all energies, and independent of which surface is used. These results are consistent with recent experimental results which are in good agreement with theoretical treatments which do not include the geometric phase. Relatively broad transition state resonances are observed in the rotationally resolved integral and differential cross sections. (C) 2000 American Institute of Physics. [S0021-9606(00)01013-8]. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Kendrick, BK (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, T-12,MS-B268, Los Alamos, NM 87545 USA. NR 75 TC 68 Z9 69 U1 2 U2 15 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 1 PY 2000 VL 112 IS 13 BP 5679 EP 5704 DI 10.1063/1.481143 PG 26 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 294FZ UT WOS:000085902300019 ER PT J AU Higgins, J Hollebeek, T Reho, J Ho, TS Lehmann, KK Rabitz, H Scoles, G Gutowski, M AF Higgins, J Hollebeek, T Reho, J Ho, TS Lehmann, KK Rabitz, H Scoles, G Gutowski, M TI On the importance of exchange effects in three-body interactions: The lowest quartet state of Na(3) SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ADAPTED PERTURBATION-THEORY; POTENTIAL-ENERGY SURFACES; SET SUPERPOSITION ERROR; DER-WAALS TRIMERS; INTERMOLECULAR FORCES; LASER SPECTROSCOPY; EXCITED-STATES; SOLID ARGON; MONTE-CARLO; CLUSTERS AB Three-body interactions in a homonuclear van der Waals bound trimer (the 1 (4)A(2)' state of Na(3)) are studied spectroscopically for the first time using laser induced emission spectroscopy on a liquid helium nanodroplet coupled with ab initio calculations. The van der Waals bound, spin polarized sodium trimers are prepared via pickup by, and selective survival in, a beam of helium clusters. Laser excitation from the 1 (4)A(2)' to the 2 (4)E' state, followed by dispersion of the fluorescence emission, allows for the resolution of the structure due to the vibrational levels of the lower state and for the gathering of precise information on the three-body interatomic potential. From previous experiments on Na(2) we know that the presence of the liquid helium perturbs the spectra by a very small amount [see J. Higgins , J. Phys. Chem. 102, 4952 (1998)]. Ab initio potential energy calculations are carried out at 42 geometries of the lowest quartet state using the coupled cluster method at the single, double, and noniterative triple excitations level [CCSD(T)]. The full potential energy surface is obtained from the ab initio points using an interpolation procedure based on a Reproducing Kernel Hilbert Space (RKHS) methodology. This surface is compared to a second, constructed using an analytical model function for both the two-body interaction and the nonadditivity correction. The latter is calculated as the difference between the CCSD(T) points and the sum of the two-body interactions. The bound vibrational states are calculated using the two potential energy surfaces and are compared to the experimentally determined levels. The calculated bound levels are combined with an intensity calculation of the nu(2)" mode of E' symmetry derived from a Jahn-Teller analysis of the excited electronic state. The calculated frequencies of nu(1)" and nu(2)" are found to be 37.1 cm(-1) and 44.7 cm(-1), respectively, using the RKHS potential surface while values of 37.1 cm(-1) and 40.8 cm(-1) are obtained from the analytical potential. These values are found to be in good to fair agreement with those obtained from the emission spectrum and to be significantly different from any values calculated from additive potential energy surfaces. The 1 (4)A(2)' Na(3) potential energy surface is characterized by a D(3h) symmetry minimum of -850 cm(-1) (relative to the three 3 (2)S Na atom dissociation limit) with a bond distance of 4.406 Angstrom. This bond distance differs by about 0.8 Angstrom from the value of 5.2 Angstrom found for the sodium triplet dimer. This means that approximately 80% of the binding energy at the potential minimum is due to three-body effects. This strong nonadditivity is overwhelmingly due to the deformability of the valence electron density of the Na atoms which leads to a significant decrease of the exchange overlap energy in the trimer. (C) 2000 American Institute of Physics. [S0021-9606(00)01813-4]. C1 Princeton Univ, Dept Chem, Princeton, NJ 08544 USA. Pacific NW Lab, Richland, WA 99352 USA. Univ Gdansk, Dept Chem, PL-80952 Gdansk, Poland. RP Higgins, J (reprint author), Princeton Univ, Dept Chem, Princeton, NJ 08544 USA. NR 49 TC 52 Z9 52 U1 1 U2 7 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 APR 1 PY 2000 VL 112 IS 13 BP 5751 EP 5761 DI 10.1063/1.481150 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 294FZ UT WOS:000085902300026 ER PT J AU Sevy, ET Muyskens, MA Rubin, SM Flynn, GW Muckerman, JT AF Sevy, ET Muyskens, MA Rubin, SM Flynn, GW Muckerman, JT TI Competition between photochemistry and energy transfer in ultraviolet-excited diazabenzenes. I. Photofragmentation studies of pyrazine at 248 nm and 266 nm SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID COLLISIONAL VIBRATIONAL-RELAXATION; BENZENE-DERIVATIVES; INFRARED-EMISSION; LARGE MOLECULES; TRIPLET-STATE; T1 PYRAZINE; DEACTIVATION; EXCITATION; PYRIMIDINE; LASER AB The quantum yield for the formation of HCN from the photodissociation of pyrazine excited at 248 nm and 266 nm is determined by IR diode probing of the HCN photoproduct. HCN photoproducts from excited pyrazine are produced via three different dissociation channels, one that is extremely "prompt" and two others that are "late." The total quantum yield from all reaction channels obtained at low quencher gas pressures, phi = 1.3 +/- 0.2 for 248 nm and 0.5 +/- 0.3 for 266 nm, is in agreement with preliminary studies of this process as well as recent molecular beam studies. To investigate if HCN production is the result of pyrazine multiphoton absorption, this photodissociation process has been further studied by observing the HCN quantum yield as a function of total quencher gas pressure (10 mTorr pyrazine, balance SF(6)) and as a function of 248 nm laser fluence from 2.8 to 82 mJ/cm(2). At the highest SF(6) pressures, the HCN quantum yield shows strong positive correlation with laser fluence, indicating that the "prompt" channel is the result of multiphoton absorption; however, at low pressure, the HCN quantum yield is affected little by changing laser fluence, indicating that the majority of the HCN photoproducts at low pressure are produced from pyrazine which has absorbed only one UV photon. At the lowest pressures sampled, HCN produced from the one-photon "late" process accounts for more than 95% of all HCN formed (at low laser fluence). At high pressures the single photon "late" pyrazine dissociation is quenched, and HCN produced at high quencher gas pressures comes only from the multiphoton absorption channel, which can be clearly observed to depend on laser fluence. The HCN quantum yield as a function of laser intensity at high pressure has been fit to a quadratic function that can be used to determine the amount of "prompt" "unquenched" HCN produced from multiphoton photodissociation. Additionally, the information theoretic prior functions for energy disposal in the 248 nm photodissociation of pyrazine to form HCN have also been developed. Prior functions for one, two, and three-photon absorption indicate that only HCN with near room temperature translational energy comes from the one-photon process and that all HCN molecules with large amounts of translational energy are produced by multiphoton processes. Finally, analysis of the quenching data within the context of a strong collision model allows an estimate of the rate constant for HCN production from pyrazine for the major "late" channel, k(d1s) = 1.69 x 10(5) s(-1), for 248 nm excitation, and k(d1s) = 1.33 x 10(4) s(-1) for 266 nm excitation. After 266 nm excitation, pyrazine produced by the major one-photon channel lives for almost an order of magnitude longer than after 248 nm excitation. (C) 2000 American Institute of Physics. [S0021-9606(00)00310-X]. C1 Columbia Univ, Dept Chem, New York, NY 10027 USA. Columbia Univ, Columbia Radiat Lab, New York, NY 10027 USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Calvin Coll, Dept Chem & Biochem, Grand Rapids, MI 49546 USA. RP Sevy, ET (reprint author), Columbia Univ, Dept Chem, New York, NY 10027 USA. RI Muckerman, James/D-8752-2013 NR 57 TC 27 Z9 27 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 1 PY 2000 VL 112 IS 13 BP 5829 EP 5843 DI 10.1063/1.481157 PG 15 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 294FZ UT WOS:000085902300033 ER PT J AU Nanbu, S Gray, SK Kinoshita, T Aoyagi, M AF Nanbu, S Gray, SK Kinoshita, T Aoyagi, M TI Theoretical study of the potential energy surfaces and bound states of HCP SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID VIBRATION-ROTATION SPECTRUM; GAUSSIAN-BASIS SETS; CONFIGURATION-INTERACTION; REACTIVE SCATTERING; ELECTRONIC-SPECTRUM; QUANTUM DYNAMICS; METHINOPHOSPHIDE; DISSOCIATION; BANDS AB Global, ab initio potential energy surfaces for HCP in its ground 1 (1)Sigma(+) (1 (1)A') and low-lying excited 1 (1)A ", 2 (1)A', and 1 (1)Delta(2 (1)A ") electronic states are determined. The multireference configuration interaction method at the double zeta with polarization basis set level is used, although some calculations augmented with diffuse functions are also discussed. Numerous quantum mechanical rovibrational states are then obtained for these surfaces, with emphasis on those corresponding to excited electronic state levels which have not been studied theoretically before. The results agree reasonably well with available experimental data for the 1 (1)A " state. Furthermore, the presence of certain local minima on the 1 (1)A " and 2 (1)A' surfaces leads to one new series of levels on the 1 (1)A " surface, and two new series on the 2 (1)A' surface. (C) 2000 American Institute of Physics. [S0021-9606(00)30413-5]. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Inst Mol Sci, Ctr Comp, Okazaki, Aichi 4448585, Japan. RP Nanbu, S (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 36 TC 7 Z9 7 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 1 PY 2000 VL 112 IS 13 BP 5866 EP 5876 DI 10.1063/1.481159 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 294FZ UT WOS:000085902300036 ER PT J AU Dohnalek, Z Kimmel, GA Ciolli, RL Stevenson, KP Smith, RS Kay, BD AF Dohnalek, Z Kimmel, GA Ciolli, RL Stevenson, KP Smith, RS Kay, BD TI The effect of the underlying substrate on the crystallization kinetics of dense amorphous solid water films SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID VAPOR-DEPOSITED ICE; REFRACTIVE-INDEX; MOLECULAR-BEAM; SOLAR-SYSTEM; 150 K; SPECTROSCOPY; TRANSITION; GROWTH AB The crystallization kinetics of thin, dense amorphous solid water films deposited on crystalline ice and Pt(111) substrates are investigated. A dramatic acceleration of the crystallization rate is observed for amorphous films on crystalline ice substrates. The acceleration originates from the absence of the nucleation process on the crystalline ice substrate which serves as a two-dimensional nucleus for the growth of the crystalline phase. This contrasts with the crystallization on a Pt(111) substrate which proceeds via bulk nucleation and three-dimensional growth. Activation energies for growth and nucleation are determined to be 56 and 140 kJ/mol, respectively, using the apparent activation energies measured on crystalline ice and Pt(111) substrates. For amorphous films deposited on crystalline ice substrates, the crystallization rate decreases rapidly with increasing distance from the crystalline ice substrate most probably due to crystallization-induced cracking of the films. (C) 2000 American Institute of Physics. [S0021-9606(00)71913-1]. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Kay, BD (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, 902 Battelle Blvd,POB 999,MSN K8-88, Richland, WA 99352 USA. RI Smith, Scott/G-2310-2015; OI Smith, Scott/0000-0002-7145-1963; Kimmel, Greg/0000-0003-4447-2440; Dohnalek, Zdenek/0000-0002-5999-7867 NR 32 TC 73 Z9 74 U1 3 U2 20 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 1 PY 2000 VL 112 IS 13 BP 5932 EP 5941 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 294FZ UT WOS:000085902300044 ER PT J AU Adair, DM Worsham, PL Hill, KK Klevytska, AM Jackson, PJ Friedlander, AM Keim, P AF Adair, DM Worsham, PL Hill, KK Klevytska, AM Jackson, PJ Friedlander, AM Keim, P TI Diversity in a variable-number tandem repeat from Yersinia pestis SO JOURNAL OF CLINICAL MICROBIOLOGY LA English DT Article ID STRAINS; PLAGUE AB We have identified a tetranucleotide repeat sequence, (CAAA)(N), in the genome of Yersinia pestis, the causative agent of plague. This variable-number tandem repeat (VNTR) region has nine alleles and great diversity (calculated as 1 minus the sum of the squared allele frequencies) (diversity value, 0.82) within a set of 35 diverse Y. pestis strains. In contrast, the nucleotide sequence of the lcrV (low-calcium-response) gene differed only slightly among these strains, having a haplotype diversity value of 0.17. Replicated cultures, phenotypic variants of particular strains, and extensively cultured replicates within strains did not differ in VNTR allele type, Thus, while a high mutation rate must contribute to the great diversity of this locus, alleles appear stable under routine laboratory culture conditions. The classic three plague biovars did not have single identifying alleles, although there were allelic biases within biovar categories. The antiqua biovar was the most diverse, with four alleles observed in 5 strains, while the orientalis and mediaevalis biovars exhibited five alleles in 21 strains and three alleles in 8 strains, respectively. The CAAA VNTR is located immediately adjacent to the transcriptional promoters for flanking open reading frames and may affect their activity. This VNTR marker may provide a high-resolution tool for epidemiological analyses of plague. C1 No Arizona Univ, Dept Biol Sci, Flagstaff, AZ 86011 USA. USA, Med Res Inst Infect Dis, Ft Detrick, MD 21702 USA. Univ Calif Los Alamos Natl Lab, Environm Mol Biol Grp, Los Alamos, NM 87545 USA. RP Keim, P (reprint author), No Arizona Univ, Dept Biol Sci, POB 5640, Flagstaff, AZ 86011 USA. RI Keim, Paul/A-2269-2010 NR 15 TC 91 Z9 110 U1 0 U2 3 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 USA SN 0095-1137 J9 J CLIN MICROBIOL JI J. Clin. Microbiol. PD APR PY 2000 VL 38 IS 4 BP 1516 EP 1519 PG 4 WC Microbiology SC Microbiology GA 301GN UT WOS:000086302500037 PM 10747136 ER PT J AU Gao, Y Thevuthasan, S McCready, DE Engelhard, M AF Gao, Y Thevuthasan, S McCready, DE Engelhard, M TI MOCVD growth and structure of Nb- and V-doped TiO2 films on sapphire SO JOURNAL OF CRYSTAL GROWTH LA English DT Article DE MOCVD; doped TiO2; oxide thin films ID CHEMICAL-VAPOR-DEPOSITION; PHOTOCATALYTIC ACTIVITY; THIN-FILMS; ELLIPSOMETRIC ANALYSIS; TIO2(110) SURFACES; RUTILE FILMS; EPITAXY; ACIDITY; NB2O5; OXIDE AB Nb- and V-doped TiO2 thin films at a doping level up to 20 and 40 at%, respectively, have been grown on sapphire (0 0 0 1), (1 1 (2) over bar 0), and (0 1 (1) over bar 2) by metalorganic chemical vapor deposition. The Nb-doped TiO2 films are epitaxial rutile films, but the V-doped TiO2 films exhibit phase separation. The epitaxial orientation relationships for the Nb-doped TiO2 films were determined by X-ray diffraction (phi scans). Rutherford backscattering and X-ray theta rocking curves reveal that the atomic alignment in the growth direction is much better for the Nb-doped TiO2 grown on sapphire (0 0 0 1) than on sapphire(1 1 2 0) and (0 1 I 2). On the other hand, the in-plane alignment for the latter films is better than that for the former. Rutherford backscattering also shows that Nb atoms substitutionally incorporate at cation sites in the rutile lattice. X-ray photoelectron spectroscopy reveals that the oxidation state of both Ti and Nb is 4 +. In contrast, XPS shows Ti4+ and V5+ for the V-doped TiO2 films. X-ray diffraction and atomic force microscopy indicate that the V-doped TiO2 films are comprised of epitaxial TiO2 rutile islands in a V2O5 matrix. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Gao, Y (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, POB 999,MS K8-93, Richland, WA 99352 USA. RI Engelhard, Mark/F-1317-2010; OI Engelhard, Mark/0000-0002-5543-0812 NR 41 TC 44 Z9 45 U1 3 U2 28 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 APR PY 2000 VL 212 IS 1-2 BP 178 EP 190 DI 10.1016/S0022-0248(00)00010-5 PG 13 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 307WX UT WOS:000086678100027 ER PT J AU Hawley, ME Brown, GW Yashar, PC Kwon, C AF Hawley, ME Brown, GW Yashar, PC Kwon, C TI H-dependent magnetic domain structures in La0.67Sr0.33MnO3 thin films SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 11th American Conference on Crystal Growth and Epitaxy CY AUG 01-06, 1999 CL TUCSON, ARIZONA SP Assoc Crystal Growth, NASA, Div Micrograv Sci & Applicat, Adv Ceram Corp, Adv Specialty Chem, Bicron Opt, Capen Simulat Inc, Cleveland Crystals Inc, Crystal Associates Inc, Crystal Photon Inc, Crystal Technol Inc, Engis Corp, Engelhard-Clal LP, INRAD Inc, Johnson Matthey, Div Electr, Johnson Matthey, Div Alfa Aesar, Johnson Matthey, Div Mfg Technol, Litton Airton Synopt, Lockheed Martin Sanders, OPTOVAC, PROCHEM, Quantum Technol Inc, Sawyer Res Prod, Sensors Unltd Inc, Thermcraft Inc, II-VI Inc, Zirmat Corp AB Maze- and bubble-like magnetic domain structures hale been observed under ambient conditions in La0.67Sr0.33MnO3 (LSMO) films by magnetic force microscopy (MFM) for films grown on a compressive (LaAlO3) lattice-mismatched substrate. The substrate-induced stress in this soft magnetic material appears to be a necessary but not sufficient condition For the appearance of these structures. i.e. no magnetic structure has been seen for other films grown under similar conditions on the same substrate with similar distortions to the unit cell. In this study, in order to understand the stability of these structures, we have examined two films grown at 750 degrees C and three films grown at 800 C by pulsed-laser deposition by scanning tunneling and magnetic force microscopy to obtain microstructure and domain structures as a function of in-plane magnetic field strength. The latter films consisted of pitted coalesced layers with some surface 3D growth Although the films were nominally grown under the same conditions, there were subtle differences in the domain structure, wall spacing, the latter due in part to differences in film thickness, and response to an applied in-plane magnetic field. As the held was increased. the maze-libe structures became stripe domains with reduced out-of-plane magnetization and decreased wall spacing, consistent with parallel rather than antiparallel alignment of in-plane spin polarization. After removal of the field, the stripe domains remained but the wall spacing and z polarization component returned to the original value. For one 800 degrees C film the field required for changes in and disappearance of the domains paralleled the slope in the field-dependent magnetization. In contrast, the magnetic structure for one film with a thin insulating cap layer was reversible, suggesting that the walls were pinned by the cap. Published by Elsevier Science B.V. C1 Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Hawley, ME (reprint author), Los Alamos Natl Lab, Div Mat Sci & Technol, MS-G755, Los Alamos, NM 87545 USA. RI Kwon, Chuhee/A-8687-2008 NR 10 TC 19 Z9 19 U1 3 U2 11 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 APR PY 2000 VL 211 IS 1-4 BP 86 EP 92 DI 10.1016/S0022-0248(99)00849-0 PG 7 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 299LG UT WOS:000086199600017 ER PT J AU Biefeld, RM Phillips, JD Kurtz, SR AF Biefeld, RM Phillips, JD Kurtz, SR TI InAsSb/InPSb strained-layer superlattice growth using metal-organic chemical vapor deposition SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 11th American Conference on Crystal Growth and Epitaxy CY AUG 01-06, 1999 CL TUCSON, ARIZONA SP Assoc Crystal Growth, NASA, Div Micrograv Sci & Applicat, Adv Ceram Corp, Adv Specialty Chem, Bicron Opt, Capen Simulat Inc, Cleveland Crystals Inc, Crystal Associates Inc, Crystal Photon Inc, Crystal Technol Inc, Engis Corp, Engelhard-Clal LP, INRAD Inc, Johnson Matthey, Div Electr, Johnson Matthey, Div Alfa Aesar, Johnson Matthey, Div Mfg Technol, Litton Airton Synopt, Lockheed Martin Sanders, OPTOVAC, PROCHEM, Quantum Technol Inc, Sawyer Res Prod, Sensors Unltd Inc, Thermcraft Inc, II-VI Inc, Zirmat Corp ID LIGHT-EMITTING-DIODES; MIDINFRARED LASERS AB We report on the metal-organic chemical vapor deposition (MOCVD) of strained layer superlattices (SLSs) of InAsSb/InPSb as well as mid-infrared optically pumped lasers grown using a high-speed rotating disk reactor (RDR). The devices contain AlAsSb cladding layers and strained, type-I, InAsSb/InPSb active regions. By changing the layer thickness and composition of InAsSb/InPSb SLSs, we have prepared structures with low-temperature ( < 20 K) photoluminescence wavelengths ranging from 3.4 to 4.8 mu m. We find a variation in band gap of 0.272-0.324 eV for layer thicknesses of 9.0-18.2 nm From these data we have estimated a valence band offset for the InAsSb/InPSb interface of about 400 meV. The optical properties of the superlattices revealed an anomalous low-energy transition that can be assigned to an antimony-rich interfacial layer in the superlattice. An InAsSb/InPSb SLS, laser was grown on an InAs substrate with AlAs0.16Sb0.84 cladding layers. A lasing threshold and spectrally narrowed laser emission were seen from 80-200 K, the maximum temperature where lasing occurred. The temperature dependence of the SLS laser threshold is described by a characteristic temperature. T-0 = 72 K. from 80 to 200 K. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Biefeld, RM (reprint author), Sandia Natl Labs, POB 5800,1113,MS 0601, Albuquerque, NM 87185 USA. RI Phillips, Jamie/E-9394-2010 NR 5 TC 3 Z9 3 U1 2 U2 8 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 APR PY 2000 VL 211 IS 1-4 BP 400 EP 404 DI 10.1016/S0022-0248(99)00822-2 PG 5 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 299LG UT WOS:000086199600071 ER PT J AU Harvey, NR Marshall, S AF Harvey, NR Marshall, S TI Defect detection from scratched 2 in. quadruplex video tape SO JOURNAL OF ELECTRONIC IMAGING LA English DT Article AB A technique is described for the detection of defects in digital video images, caused by scratching to the original 2 in. qua druplex video tape. This technique relies upon the reorientation of the digital video data into a manner similar to that in which the original analogue data would have been found on the video tape. This brings the scratched data into alignment and makes the task of detecting the scratched positions a great deal easier. In addition to enabling the detection of scratches in the video data, the technique enables new insight into the mechanisms through which the scratching was first brought about (C) 2000 SPIE and IS&T. [S1017-9909(00)00902-8]. C1 Univ Calif Los Alamos Natl Lab, Space & Remote Sensing Sci Grp, Los Alamos, NM 87545 USA. Univ Strathclyde, Dept Elect & Elect Engn, Glasgow G1 1XW, Lanark, Scotland. RP Harvey, NR (reprint author), Univ Calif Los Alamos Natl Lab, Space & Remote Sensing Sci Grp, POB 1663, Los Alamos, NM 87545 USA. NR 5 TC 2 Z9 2 U1 0 U2 0 PU I S & T - SOC IMAGING SCIENCE TECHNOLOGY PI SPRINGFIELD PA 7003 KILWORTH LANE, SPRINGFIELD, VA 22151 USA SN 1017-9909 J9 J ELECTRON IMAGING JI J. Electron. Imaging PD APR PY 2000 VL 9 IS 2 BP 203 EP 216 DI 10.1117/1.482740 PG 14 WC Engineering, Electrical & Electronic; Optics; Imaging Science & Photographic Technology SC Engineering; Optics; Imaging Science & Photographic Technology GA 325MK UT WOS:000087679200011 ER PT J AU Wei, CH Xie, ZY Edgar, JH Zeng, KC Lin, JY Jiang, HX Chaudhuri, J Ignatiev, C Braski, DN AF Wei, CH Xie, ZY Edgar, JH Zeng, KC Lin, JY Jiang, HX Chaudhuri, J Ignatiev, C Braski, DN TI MOCVB growth of GaBN on 6H-SiC (0001) substrates SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article DE GaBN; MOCVD; BN; GaN ID BORON; EPITAXY AB BxGa1-xN films were deposited on 6H-SiC (0001) substrates at 1000 degrees C by low pressure MOVPE using diborane, trimethylgallium, and ammonia as precursors. The presence of boron was detected by Auger scanning microprobe, the shift of the (00.2) x-ray diffraction peak, and low-temperature photoluminescence. A single-phase BxGa1-xN alloy with x = 1.5% was produced at the gas phase B/Ga ratio of 0.005. Phase separation into wurtzite BGaN and the B-rich phase occurred for a B/Ga ratio in the 0.01-0.2 range. Only BN was formed for B/Ga > 0.2. The B-rich phase was identified as h-BN with sp(2) bonding based on the results of Fourier transform infrared spectroscopy. As the diborane flow exceeds the threshold concentration, the growth rate of BGaN decreases sharply, because the growth of GaN is poisoned by the formation of the slow growing BN phase. The bandedge emission of BxGa1-xN varies from 3.45 1 eV for x = 0% with FWHM of 39.2 meV to 3.465 eV for x = 1.5% with FWHM of 35.1 meV. The narrower FWHM indicates that the quality of GaN epilayer is improved with a small amount of boron incorporation. The PL linewidths become broader as more boron is introduced into the solid solution. C1 Kansas State Univ, Dept Chem Engn, Manhattan, KS 66506 USA. Kansas State Univ, Dept Phys, Manhattan, KS 66506 USA. Wichita State Univ, Dept Mech Engn, Wichita, KS 67260 USA. Oak Ridge Natl Lab, High Temp Mat Lab, Oak Ridge, TN 37831 USA. RP Wei, CH (reprint author), Kansas State Univ, Dept Chem Engn, Durland Hall, Manhattan, KS 66506 USA. RI Lin, Jingyu/A-7276-2011; Jiang, Hongxing/F-3635-2011; Chaudhuri, Jharna/E-8863-2013 OI Lin, Jingyu/0000-0003-1705-2635; Jiang, Hongxing/0000-0001-9892-4292; NR 13 TC 9 Z9 9 U1 3 U2 24 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 APR PY 2000 VL 29 IS 4 BP 452 EP 456 DI 10.1007/s11664-000-0160-y PG 5 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA 349QL UT WOS:000089057100010 ER PT J AU Woodford, DA Wereszczak, AA Bakker, WT AF Woodford, DA Wereszczak, AA Bakker, WT TI Stress relaxation testing as a basis for creep analysis and design of silicon nitride SO JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT International Gas Turbine and Aeroengine Congress and Exhibition CY JUN 07-10, 1999 CL INDIANAPOLIS, INDIANA ID HIGH-TEMPERATURE; CERAMICS AB A new approach to tensile creep resting and analysis based on stress relaxation is described for sintered silicon nitride. Creep rate data covering up to Jive orders of magnitude were generated in tests lasting less than one day. Tests from various initial stresses at temperatures from 1250 degreesC to 1350 degreesC were analyzed and compared with creep rates measured during conventional constant load testing. It was shown that at least 40 percent of the creep strain accumulated under all test conditions was recoverable, and that the deformation could properly be described as viscoelastic/plastic. Tears were conducted to establish the level of repeatability and the effects of various thermomechanical histories, It was shown that none of the prior exposures led to significant impairment in creep strength. The results were used for three different grades to establish the value of the accelerated rest to compare creep strengths for acceptance and for optimization. Several useful correlations were obtained between stress and creep rate. The systematic creep rare dependence as a function of loading strain prior to relaxation provided a possible basis fill design in terms of a secant modulus analysis. C1 Mat Performance Anal MPa Inc, Santa Barbara, CA 93101 USA. Oak Ridge Natl Lab, High Temp Mat Lab, Oak Ridge, TN 37831 USA. Elect Power Res Inst, Palo Alto, CA 94303 USA. RP Woodford, DA (reprint author), Mat Performance Anal MPa Inc, 1707 Garden St, Santa Barbara, CA 93101 USA. RI Wereszczak, Andrew/I-7310-2016 OI Wereszczak, Andrew/0000-0002-8344-092X NR 15 TC 8 Z9 8 U1 0 U2 1 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0742-4795 J9 J ENG GAS TURB POWER JI J. Eng. Gas. Turbines Power-Trans. ASME PD APR PY 2000 VL 122 IS 2 BP 206 EP 211 DI 10.1115/1.483196 PG 6 WC Engineering, Mechanical SC Engineering GA 404QF UT WOS:000167111500004 ER PT J AU More, KL Tortorelli, PF Ferber, MK Walker, LR Keiser, JR Miriyala, N Brentnall, WD Price, JR AF More, KL Tortorelli, PF Ferber, MK Walker, LR Keiser, JR Miriyala, N Brentnall, WD Price, JR TI Exposure of ceramics and ceramic matrix composites in simulated and actual combustor environments SO JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT International Gas Turbine and Aeroengine Congress and Exhibition CY JUN 07-10, 1999 CL INDIANAPOLIS, INDIANA ID DEPOSITED SILICON-CARBIDE; WATER-VAPOR; OXIDATION AB A high-temperature, high-pressure, tube furnace has been used to evaluate the long term stability, of different monolithic ceramic and ceramic matrix composite materials in a simulated combustor environment. All of the tests have been run at 150 psia, 1204 degreesC, and 15 percent steam in incremental 500 h runs. The major advantage of this system is the high sample throughput; >20 samples can be exposed in each tube at the same time under similar exposure conditions. Microstructural evaluations of the samples were conducted after each 500 h exposure to characterize the extent of surface damage, to calculate surface recession rates, and to determine degradation mechanisms for the different materials. The validity of this exposure rig for simulating real combustor environments was established by comparing materials exposed in the rest rig and combustor liner materials exposed for similar times in an actual gas turbine combustor under commercial operating conditions. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Solar Turbines Inc, San Diego, CA USA. RP More, KL (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI More, Karren/A-8097-2016 OI More, Karren/0000-0001-5223-9097 NR 13 TC 16 Z9 16 U1 0 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0742-4795 J9 J ENG GAS TURB POWER JI J. Eng. Gas. Turbines Power-Trans. ASME PD APR PY 2000 VL 122 IS 2 BP 212 EP 218 DI 10.1115/1.483197 PG 7 WC Engineering, Mechanical SC Engineering GA 404QF UT WOS:000167111500005 ER PT J AU Bange, ME Beaudoin, AJ Stout, M Chen, SR MacEwen, SR AF Bange, ME Beaudoin, AJ Stout, M Chen, SR MacEwen, SR TI Predictive modeling of the nonuniform deformation of the aluminum alloy 5182 SO JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article ID CRYSTALLOGRAPHIC TEXTURE; FCC METALS; EVOLUTION AB We pose an experimental model for hot deformation that, in complexity, falls between a homogeneous laboratory test and an industrial process. Our objective is to document a transition between two distinct models of thermally-activated deformation: diffusion controlled solute drag and hardening with concurrent recovery of dislocations. We demonstrate that constitutive equations for plasticity, describing different regimes of dislocation kinetics and calibrated with a minimum of adjustable constants, can be incorporated into finite element analysis and used reliably to predict the mechanical response to a nonuniform body. [S0094-4289(00)00302-9]. C1 Univ Illinois, Dept Mech & Ind Engn, Urbana, IL 61801 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Alcan Int Ltd, Kingston, ON, Canada. RP Bange, ME (reprint author), Univ Illinois, Dept Mech & Ind Engn, 1206 W Green St, Urbana, IL 61801 USA. NR 17 TC 1 Z9 1 U1 0 U2 3 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0094-4289 J9 J ENG MATER-T ASME JI J. Eng. Mater. Technol.-Trans. ASME PD APR PY 2000 VL 122 IS 2 BP 149 EP 156 DI 10.1115/1.482780 PG 8 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 404PD UT WOS:000167108600001 ER PT J AU Tokar, RL Gary, SP Gosling, JT McComas, DJ Skoug, RM Smith, CW Ness, NF Haggerty, D AF Tokar, RL Gary, SP Gosling, JT McComas, DJ Skoug, RM Smith, CW Ness, NF Haggerty, D TI Suprathermal ions and MHD turbulence observed upstream of an interplanetary shock by Advanced Composition Explorer SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID TRAVELING SHOCKS; 1600-KEV PROTONS; SOLAR-WIND; ACCELERATION; 35-KEV; INSTABILITIES; WAVES AB Observations of a beam-like ion distribution upstream of an interplanetary shock near 1 AU are presented in this paper. Such observations upstream of interplanetary shocks are rare, with only one known example in the literature, a shock studied by Voyager 1 at about 2.25 AU. The ions are observed by the Advanced Composition Explorer (ACE) Solar Wind Electron Proton Alpha Monitor (SWEPAM) and Energetic Proton Alpha Monitor (EPAM) instruments and associated MHD fluctuations are observed by the ACE Bartol. Research Institute Magnetometer (MAG) instrument. The energy per charge of the ions observed by SWEPAM extends from similar to 700 eV/q to similar to 3 keV/q in the spacecraft frame, while the ions seen by EPAM extend to similar to 100 keV in the spacecraft frame. The fluctuating fields observed by MAG have spacecraft frame frequencies from about 0.03 to 0.3 Hz. The particle and field data are combined to determine the ion phase space density parallel and perpendicular to the ambient magnetic field, and the results suggest that a field-aligned beam moving away from the shock is observed. Linear Vlasov theory predicts that the observed ions can drive fluctuations-with the observed frequencies and polarization. In addition, fluctuating field amplitudes are in qualitative agreement with simulation predictions. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. RP Tokar, RL (reprint author), Univ Calif Los Alamos Natl Lab, MS D466, Los Alamos, NM 87545 USA. NR 25 TC 7 Z9 7 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD APR 1 PY 2000 VL 105 IS A4 BP 7521 EP 7531 DI 10.1029/1999JA000097 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 300FZ UT WOS:000086222800011 ER PT J AU Su, YJ Borovsky, JE Thomsen, MF Elphic, RC McComas, DJ AF Su, YJ Borovsky, JE Thomsen, MF Elphic, RC McComas, DJ TI Plasmaspheric material at the reconnecting magnetopause SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID MAGNETOSPHERIC PLASMA ANALYZER; GEOSYNCHRONOUS ORBIT; DAYSIDE MAGNETOPAUSE; FLOW; CONVECTION; ORIGIN AB During geomagnetic storms, cold and dense plasmaspheric material is observed to drain toward the dayside magnetopause when the solar wind pressure is strong and the interplanetary magnetic field (IMF) is southward What is the fate of draining plasmaspheric material at the magnetopause? Does the plasmaspheric material participate in the dayside reconnection and then convect on open field lines through the polar cap? Or does the material become captured into the low-latitude boundary layer and then convect on closed field lines around the flanks of the magnetosphere? In this paper, we present observations from the Los Alamos magnetospheric plasma analyzers (MPA) onboard five satellites at geosynchronous orbit during 86 plasmaspheric drainage events. For a set of events where cold plasmaspheric material is observed immediately adjacent to the magnetopause/low-latitude boundary layer, we examine the detailed ion distributions, from similar to 1 eV to similar to 40 keV, for evidence that the draining plasmaspheric ions and the entering magnetosheath ions are simultaneously present on the same flux tube. Ten cases out of 57 are found where magnetosheath ions and plasmaspheric ions were unambiguously present simultaneously in the same flux tube, which is a signature that the plasmaspheric flux tubes do experience dayside reconnection, An additional ten cases strongly, but not as definitively, support this conclusion. Further, six of seven events with available IMF information have velocity space signatures that are consistent with expectations based on the reconnection process. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Su, YJ (reprint author), Univ Calif Los Alamos Natl Lab, NIS-1,MS D466, Los Alamos, NM 87545 USA. NR 20 TC 35 Z9 35 U1 0 U2 4 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 APR 1 PY 2000 VL 105 IS A4 BP 7591 EP 7600 DI 10.1029/1999JA000266 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 300FZ UT WOS:000086222800017 ER PT J AU Kuznetsova, MM Hesse, M Winske, D AF Kuznetsova, MM Hesse, M Winske, D TI Toward a transport model of collisionless magnetic reconnection SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID PARTICLE SIMULATION; CURRENT SHEETS; TEARING MODE; MAGNETOTAIL CONFIGURATION; HYBRID SIMULATIONS; MHD SIMULATIONS; X-LINE; DYNAMICS; FIELD; INSTABILITIES AB An absence of theoretical justification for the magnitude of resistivity is one of the major limitations of large-scale simulations of magnetic reconnection in collisionless magnetospheric plasma. We took advantage of the results of recent progress in kinetic modeling of collisionless dissipation in the vicinity of the magnetically neutral X point aiming to find ways to represent small-scale kinetic effects in large-scale models. The study was based on a combination of hybrid and particle methods and on analytical analysis. A comprehensive hybrid simulation code which incorporates the leading terms in electron dynamics responsible for breaking the frozen magnetic flux constraint (electron bulk flow inertia and nongyrotropic pressure effects) was utilized. The results of the comprehensive hybrid model were found to be in excellent quantitative agreement with the results of full particle simulations with similar setups. Both simulations demonstrated that the actual reconnection electric field is determined primarily by kinetic quasi-viscous effects and less by electron bulk flow inertia. An analytical expression for the quasi-viscous reconnection electric field averaged over the nongyrotropic region was obtained. Similar behavior of the evaluated quasi-viscous electric field and actual reconnection electric field taken from the simulations was demonstrated. Conventional hybrid simulations with simple nongyrotropic corrections to the electric field where also performed. The model was further reduced for utilization in MHD models. Analytical expressions for the time evolution of the reconnected flux evaluated from the MHD model modified by nongyrotropic corrections appeared to be in very good agreement with the results of comprehensive kinetic simulations. The evaluated averaged quasi-viscous electric field can be substituted into large-scale simulation models. C1 NASA, Goddard Space Flight Ctr, Electrodynam Branch, Greenbelt, MD 20771 USA. Univ Calif Los Alamos Natl Lab, Div Appl Theoret Phys, Los Alamos, NM 87545 USA. RP Kuznetsova, MM (reprint author), NASA, Goddard Space Flight Ctr, Electrodynam Branch, Greenbelt, MD 20771 USA. RI Hesse, Michael/D-2031-2012; Kuznetsova, Maria/F-6840-2012 NR 42 TC 36 Z9 36 U1 0 U2 4 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 APR 1 PY 2000 VL 105 IS A4 BP 7601 EP 7616 DI 10.1029/1999JA900396 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 300FZ UT WOS:000086222800018 ER PT J AU Farrugia, CJ Gratton, FT Contin, J Cocheci, CC Arnoldy, RL Ogilvie, KW Lepping, RP Zastenker, GN Nozdrachev, MN Fedorov, A Sauvaud, JA Steinberg, JT Rostoker, G AF Farrugia, CJ Gratton, FT Contin, J Cocheci, CC Arnoldy, RL Ogilvie, KW Lepping, RP Zastenker, GN Nozdrachev, MN Fedorov, A Sauvaud, JA Steinberg, JT Rostoker, G TI Coordinated Wind, Interball/tail, and ground observations of Kelvin-Helmholtz waves at the near-tail, equatorial magnetopause at dusk: January 11, 1997 SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID INTERPLANETARY MAGNETIC-FIELD; MAGNETOSPHERIC BOUNDARY; AMPTE/IRM OBSERVATIONS; DAYSIDE MAGNETOPAUSE; EARTHS MAGNETOPAUSE; HIGH-LATITUDE; MAGNETOSHEATH; INSTABILITY; DEPENDENCE; MOTIONS AB We analyze ground magnetograms and magnetic field, ion, and electron data from Interball/tail (IT) for the period 0030-0530 UT on January 11, 1997, focusing on waves at the near-tail (similar to-13 R(E)), duskside, equatorial flank, a locale whose physical and wave properties have not been as well studied as those on the dayside. Two major interplanetary features, monitored by Wind, are relevant to this work: The very high and variable dynamic pressure and the strongly northward and generally increasing magnetic field. In this paper, we report, first, on magnetosonic waves in the magnetosheath of frequency similar to 0.15 Hz, probably generated by the mirror instability, which are Doppler shifted with respect to similar waves on the dayside. Second, we discuss Kelvin-Helmholtz (KH) waves on the magnetopause, of wavelength similar to 13-14 R(E) and frequency similar to 3.6 mHz, i.e., in the Pc 5 range. At IT, these waves appear as an envelope modulation of the magnetosonics and are recorded on ground stations at dusk. We argue that the large magnetic shear across the magnetopause and a magnetosheath flow aligned almost normal to the field stabilized the magnetopause locally. Thus these waves were generated on the dayside and propagated to the flank. Third; we examine a low-latitude boundary layer (LLBL), whose tailward stretched field and average antisunward flow were perturbed quasi-periodically. This, together with the particle behavior, suggests a complex billowy structure where hot plasma sheet and cold magnetosheath populations wind around each other while drifting antisunward. A numerical calculation using IT parameters suggests that the inner edge of the LLBL was at this time KH unstable. Fourth, over the 5-hour period the power of the KH oscillations drifts to lower frequencies which we attribute to the progressive decrease in clock angle. Fifth, transients induced by dynamic pressure pulses include a 7.5-min single, free oscillation upon arrival of a fourfold pressure release. Sixth, the long-term effect on the magnetosphere of the increasing northward pointing magnetic field and the stepwise decreasing dynamic pressure is to make the shape of the cavity progressively less blunt. A conclusion of this work is that the equatorial magnetopause can be very oscillatory with various: distinct periodicities even when the interplanetary magnetic field is strongly north. The solar wind dynamic pressure, while responsible for some, cannot explain all of this wave activity. C1 Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA. Univ Buenos Aires, Fac Ciencias Exactas & Nat, RA-1428 Buenos Aires, DF, Argentina. Univ Buenos Aires, CONICET, Inst Fis Plasma, RA-1428 Buenos Aires, DF, Argentina. Russian Acad Sci, Space Res Inst, Moscow, Russia. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Alberta, Dept Phys, Edmonton, AB, Canada. Ctr Etud Spatiale Rayonnements, Toulouse, France. Los Alamos Natl Lab, Los Alamos, NM USA. RP Farrugia, CJ (reprint author), Univ New Hampshire, Ctr Space Sci, 39 Coll Rd, Durham, NH 03824 USA. NR 39 TC 45 Z9 45 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD APR 1 PY 2000 VL 105 IS A4 BP 7639 EP 7667 DI 10.1029/1999JA000267 PG 29 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 300FZ UT WOS:000086222800021 ER PT J AU Kim, HJ Chan, AA Wolf, RA Birn, J AF Kim, HJ Chan, AA Wolf, RA Birn, J TI Can substorms produce relativistic outer belt electrons? SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID 1997 MAGNETIC STORM; GEOSYNCHRONOUS ORBIT; ENERGETIC ELECTRONS; GEOMAGNETIC STORMS; PARTICLE MOTION; RADIATION-BELT; MAGNETOSPHERE; ACCELERATION; INJECTIONS; ENHANCEMENTS AB In an effort to explain how magnetic storms can cause strong enhancements in outer belt MeV electrons, we have studied the substorm-associated acceleration of energetic (tens of keV) plasma sheet electrons and their injection into the outer-trapped region of the magnetosphere. The study is based on tracing test particles in three-dimensional MHD simulations of substorm dipolarization. The simulation-based electric and magnetic fields [Birn and Hesse, 1996] exhibit a strong earthward collapse around local midnight, leading to magnetic field dipolarization along with a corresponding induction electric field. The test particle traces show that tens of keV plasma sheet electrons can be transported from about x approximate to -20 R-E to x approximate to -10 R-E and can gain about a factor of 10 in energy. If these particles are further transported inward to L similar to 6 while conserving the first adiabatic invariant, they will have energies of an MeV or more. In the substorm acceleration process the dominant energy gain occurs during the earthward radial transport by E x B drift in the strong dipolarization region. In our calculations the electrons that gain the most energy are ones that circle a local maximum in the equatorial magnetic field strength and thus spend a relatively long time in the region of collapsing field. The first adiabatic invariant is broken at the beginning of the particle trajectory, near the neutral line, where the magnetic curvature radius can be comparable to the particle gyroradius. The second adiabatic invariant is also broken later in the process, when particles can be temporarily trapped in off-equatorial magnetic minima associated with MHD waves on the dipolarizing field lines. Estimation of the number of accelerated plasma sheet electrons indicates that the Birn-Hesse substorm, which is not particularly large, produces only similar to 2% of the number of MeV electrons observed in a typical poststorm outer belt electron enhancement. A series of substorms, some of them large, might produce a large enough enhancement, but it should be noted that this is an order of magnitude estimate, and it is rather sensitive to plasma sheet and substorm parameters. C1 Univ Calif Los Alamos Natl Lab, Space & Atmospher Sci Grp, Los Alamos, NM 87545 USA. Rice Univ, Dept Space Phys & Astron, Houston, TX 77005 USA. RP Kim, HJ (reprint author), Solar Terr Environm Lab, 3-13 Honohara, Aichi 4428507, Japan. NR 31 TC 33 Z9 34 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD APR 1 PY 2000 VL 105 IS A4 BP 7721 EP 7735 DI 10.1029/1999JA900465 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 300FZ UT WOS:000086222800026 ER PT J AU Hainfeld, JF Robinson, JM AF Hainfeld, JF Robinson, JM TI New frontiers in gold labeling: Symposium overview SO JOURNAL OF HISTOCHEMISTRY & CYTOCHEMISTRY LA English DT Editorial Material AB The Symposium New Frontiers in Gold Labeling was held at the Fifth Joint Meeting of the Japan Society of Histochemistry and Cytochemistry and the United States Histochemical Society. Speakers described technological developments in this area that improved localization of cellular components. Each presentation is summarized in this overview, and complete articles follow that describe these results in more detail. C1 Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. Ohio State Univ, Dept Physiol, Columbus, OH 43210 USA. RP Hainfeld, JF (reprint author), Brookhaven Natl Lab, Dept Biol, Bldg 463, Upton, NY 11973 USA. NR 0 TC 16 Z9 16 U1 0 U2 2 PU HISTOCHEMICAL SOC INC PI SEATTLE PA UNIV WASHINGTON, DEPT BIOSTRUCTURE, BOX 357420, SEATTLE, WA 98195 USA SN 0022-1554 J9 J HISTOCHEM CYTOCHEM JI J. Histochem. Cytochem. PD APR PY 2000 VL 48 IS 4 BP 459 EP 460 PG 2 WC Cell Biology SC Cell Biology GA 302CN UT WOS:000086347800002 PM 10727286 ER PT J AU Mayer, G Leone, RD Hainfeld, JF Bendayan, M AF Mayer, G Leone, RD Hainfeld, JF Bendayan, M TI Introduction of a novel HRP substrate-nanogold probe for signal amplification in immunocytochemistry SO JOURNAL OF HISTOCHEMISTRY & CYTOCHEMISTRY LA English DT Article; Proceedings Paper CT 5th Joint Meeting of the Japan-Society-of-Histochemistry-and-Cytochemistry / Histochemical-Society CY JUL 23-26, 1998 CL UNIV CALIFORNIA SAN DIEGO, LA JOLLA, CALIFORNIA SP Japan Soc Histochem & Cytochem, Histochem Soc, Univ Calif San Diego HO UNIV CALIFORNIA SAN DIEGO DE CARD; nanogold; immunocytochemistry; immunodot assay; silver enhancement ID CATALYZED REPORTER DEPOSITION; IN-SITU HYBRIDIZATION; FLUOROCHROME-LABELED TYRAMIDES; ELECTRON-MICROSCOPY; IMMUNOGOLD PARTICLES; SILVER ENHANCEMENT; GOLD PARTICLES; SENSITIVITY; LIGHT; IMMUNOHISTOCHEMISTRY AB Amplification of immunological signals with catalyzed reporter deposition (CARD) allows improved detection of scarce tissue antigens in light and electron microscopy. The technique takes advantage of the oxidation ability of horseradish peroxidase (HRP), in the presence of hydrogen peroxide, to yield the accumulation of one of its specific reporter-tagged substrates. This immunocytochemical approach continues to be improved by the introduction of new reporter molecules tagged to tyramine or to other HRP substrates. In this study we introduced a novel HRP substrate tagged to Nanogold particles. The amplification protocol is based on the application of a specific primary antibody, a biotinylated secondary antibody, streptavidin-HRP, and an HRP substrate coupled to Nanogold, followed by silver intensification. In addition to amplification of immunological signals of high resolution, direct accumulation of Nanogold particles at target sites by enzymatic activity of HRP improves the efficiency of the technique compared to other amplification protocols. Moreover, this approach combines the CARD amplification potentials with the ultrasmall gold probe and the silver intensification method. Immunolabeling obtained by light and electron microscopy, as well as immunodot assay using this new amplification strategy, appear to be highly sensitive, specific, and of enhanced intensity. C1 Univ Montreal, Dept Pathol & Cell Biol, Montreal, PQ H3C 3J7, Canada. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. Nanoprobes Inc, Stony Brook, NY USA. RP Bendayan, M (reprint author), Univ Montreal, Dept Pathol & Cell Biol, CP 6128 Succ,Ctr Ville, Montreal, PQ H3C 3J7, Canada. NR 35 TC 11 Z9 13 U1 0 U2 8 PU HISTOCHEMICAL SOC INC PI SEATTLE PA UNIV WASHINGTON, DEPT BIOSTRUCTURE, BOX 357420, SEATTLE, WA 98195 USA SN 0022-1554 J9 J HISTOCHEM CYTOCHEM JI J. Histochem. Cytochem. PD APR PY 2000 VL 48 IS 4 BP 461 EP 469 PG 9 WC Cell Biology SC Cell Biology GA 302CN UT WOS:000086347800003 PM 10727287 ER PT J AU Hainfeld, JF Powell, RD AF Hainfeld, JF Powell, RD TI New frontiers in gold labeling SO JOURNAL OF HISTOCHEMISTRY & CYTOCHEMISTRY LA English DT Article; Proceedings Paper CT 5th Joint Meeting of the Japan-Society-of-Histochemistry-and-Cytochemistry / Histochemical-Society CY JUL 23-26, 1998 CL UNIV CALIFORNIA SAN DIEGO, LA JOLLA, CALIFORNIA SP Japan Soc Histochem & Cytochem, Histochem Soc, Univ Calif San Diego HO UNIV CALIFORNIA SAN DIEGO DE gold; immunogold; electron microsocpy; gold labeling; gold clusters; immunocytochemistry; colloidal gold; Nanogold ID ELECTRON-MICROSCOPY; UNDECAGOLD CLUSTER; CORRELATIVE MICROSCOPY; SILVER ENHANCEMENT; LOCALIZATION; ANTIBODY; BINDING; PROTEIN; LIGHT; IMMUNOCYTOCHEMISTRY AB Recent advances in gold technology have led to probes with improved properties and performance for cell biologists: higher labeling density, better sensitivity, and greater penetration into tissues. Gold clusters, such as the 1.4-nm Nanogold, are gold compounds that can be covalently linked to Fab' antibody fragments, making small and stable probes. Silver enhancement then makes these small gold particles easily visible by EM, LM, and directly by eye. Another advance is the combination of fluorescent and gold probes for correlative microscopy. Chemical crosslinking of gold particles to many biologically active molecules has made possible many novel probes, such as gold-lipids, gold-Ni-NTA, and gold-ATP. C1 Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. Nanoprobes Inc, Stony Brook, NY USA. RP Hainfeld, JF (reprint author), Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. FU NCRR NIH HHS [RR017777]; NIGMS NIH HHS [GM 48328, GM 49564] NR 59 TC 185 Z9 186 U1 2 U2 28 PU HISTOCHEMICAL SOC INC PI SEATTLE PA UNIV WASHINGTON, DEPT BIOSTRUCTURE, BOX 357420, SEATTLE, WA 98195 USA SN 0022-1554 J9 J HISTOCHEM CYTOCHEM JI J. Histochem. Cytochem. PD APR PY 2000 VL 48 IS 4 BP 471 EP 480 PG 10 WC Cell Biology SC Cell Biology GA 302CN UT WOS:000086347800004 PM 10727288 ER PT J AU Korolyov, AV Arkhipov, VY Gaviko, VS Mukovskii, Y Arsenov, AA Lapina, TP Bader, SD Jiang, JS Nizhankovskii, VI AF Korolyov, AV Arkhipov, VY Gaviko, VS Mukovskii, Y Arsenov, AA Lapina, TP Bader, SD Jiang, JS Nizhankovskii, VI TI Magnetic properties and magnetic states in La0.9Sr0.1MnO3 SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article DE manganite; magnetic oxide; colossal magnetoresistance; magnetization curve; magnetic susceptibility; coercivity; demagnetization factor; magnetic transition ID GIANT-MAGNETORESISTANCE; DOUBLE-EXCHANGE; PHASE-DIAGRAM; LA1-XSRXMNO3; TRANSITION; X-LESS-THAN-OR-EQUAL-TO-0.17; FERROMAGNETISM AB Magnetic properties of La0.9Sr0.1MnO3 samples prepared by the floating-zone technique have been studied. The compound possesses different crystal structures at different temperatures T: a pseudo-cubic O "-type structure below 100 K, an orthorhombic O'-type between 100 and 320-340 K and a pseudo-cubic O-type structure above 340 K. Below 145 K a ferromagnetically ordered state is observed. At low temperatures (similar to 4 K) the magnetization sigma, coercivity H-c, differential susceptibility chi(0) in small fields H less than or equal to H-c, and the forced susceptibility chi(Delta) in high fields (30-50 kOe) depend on cooling conditions. After zero-held cooling (ZFC), H-c = 290 Oe, chi(0) is much smaller than the shape susceptibility chi(shape), sigma(50 kOe) = 85.5 emu/g, and chi(Delta) = 5 x 10(-5) cm(3)/g. The measurements after held cooling (FC) in 50 kOe yield H-c < 7 Oe, chi(0) = chi(shape). sigma(50 kOe) = 96 emu/g, and chi(Delta) = 2.5 x 10(-5) cm(3)/g. The sample after ZFC is magnetically heterogeneous, while after FC it is nearly homogeneous. In the heterogeneous state, similar to 20% of the sample volume is occupied by small precipitates (estimated to be 10-20 nm in size) having zero spontaneous magnetization. However, the precipitates become ferromagnetic in high fields via a metamagnetic transition. The results are interpreted within the framework of a mixed ferromagnetic-antiferromagnetic ground state model. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Russian Acad Sci, Inst Met Phys, Ural Branch, Ekaterinburg 620219, Russia. Moscow Steel & Alloys Inst, Moscow 117936, Russia. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Int Lab High Magnet Fields & Low Temp, PL-53421 Wroclaw, Poland. RP Korolyov, AV (reprint author), Russian Acad Sci, Inst Met Phys, Ural Branch, 18 S Kovalevskaya Str, Ekaterinburg 620219, Russia. RI Bader, Samuel/A-2995-2013; Gaviko, Vasilii/K-4632-2013; Alexander, Korolev/K-3036-2013 OI Gaviko, Vasilii/0000-0002-9841-9293; Alexander, Korolev/0000-0002-5104-3997 NR 21 TC 28 Z9 28 U1 0 U2 7 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 APR PY 2000 VL 213 IS 1-2 BP 63 EP 74 DI 10.1016/S0304-8853(99)00786-6 PG 12 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 305FQ UT WOS:000086529100011 ER PT J AU Chien, AT Felter, T LeMay, JD Balooch, M AF Chien, AT Felter, T LeMay, JD Balooch, M TI Nanoscale mechanical properties of polymer composites: Changes in elastic modulus and measurement of ion penetration depth due to alpha-radiation SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID INDENTATION EXPERIMENTS; HARDNESS AB The local mechanical properties of silica-reinforced silicone composites were investigated using a modified atomic force microscopy technique. Elastic modulus measurements (1.5 +/- 0.1 MPa) are consistent with bulk measurements (1.9 MPa), and changes in the modulus at the surface of the composite samples (E = 1.5 to 3.5 MPa) were observed as a result of alpha-irradiation (dose = 1.7 x 10(10) to 2.0 x 10(12) alpha/cm(2)). The sensitivity of the technique was demonstrated by a detectable change in modulus at even the small dose of 1.7 x 10(10) alpha/cm(2). The penetration depth of the alpha-particles into the material, estimated to be 22 +/- 2 mu m from the sample edge, was determined by cross-section depth profiling; and modeling of the ion penetration depth using transport of ions in matter codes (24.4 +/- 0.4 mu m) closely matched experimental observations. C1 Univ Calif Lawrence Livermore Natl Lab, Chem & Mat Sci Directorate, Livermore, CA 94551 USA. RP Chien, AT (reprint author), Univ Calif Lawrence Livermore Natl Lab, Chem & Mat Sci Directorate, Livermore, CA 94551 USA. NR 17 TC 2 Z9 2 U1 1 U2 3 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD APR PY 2000 VL 15 IS 4 BP 838 EP 841 DI 10.1557/JMR.2000.0119 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA 302MH UT WOS:000086368700002 ER PT J AU He, L Allard, LF Breder, K Ma, E AF He, L Allard, LF Breder, K Ma, E TI Nanophase Fe alloys consolidated to full density from mechanically milled powders SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID GRAIN-GROWTH; NANOCRYSTALLINE COPPER; THERMAL-STABILITY; IRON-POWDER; BEHAVIOR; ATTRITION; MICROSTRUCTURE; SIZE; NANOCOMPOSITES; MICROHARDNESS AB Nanophase elemental Fe powders prepared by mechanical milling were sinter forged to full density with an average grain size in the nanophase range (below 100 nm). If Cu additions are introduced during milling to form supersaturated solid solutions (Fe85Cu15 and Fe60Cu40), grain sizes can be easily controlled to below 50 nm after consolidation. For Fe-Cu, it was observed that atomic level alloying between the two elements during milling was very helpful for obtaining a homogeneous microstructure and nanocrystalline grain/domain sizes in the consolidated product. The advantages of using sinter forging (upset die forging), as well as the role of the Cu addition, in the retention of nanocrystalline grain sizes are discussed. The consolidated Fe alloys exhibit very high strength under compression, further demonstrating that low populations of flaws and nanophase grain structures were attained in the consolidated products. C1 Louisiana State Univ, Dept Mech Engn, Baton Rouge, LA 70803 USA. Oak Ridge Natl Lab, High Temp Mat Lab, Oak Ridge, TN 37831 USA. RP Ma, E (reprint author), Johns Hopkins Univ, Dept Mat Sci & Engn, Baltimore, MD 21218 USA. RI Ma, En/A-3232-2010 NR 38 TC 7 Z9 7 U1 0 U2 2 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD APR PY 2000 VL 15 IS 4 BP 904 EP 912 DI 10.1557/JMR.2000.0129 PG 9 WC Materials Science, Multidisciplinary SC Materials Science GA 302MH UT WOS:000086368700012 ER PT J AU Wang, JG Choi, BW Nieh, TG Liu, CT AF Wang, JG Choi, BW Nieh, TG Liu, CT TI Nano-scratch behavior of a bulk Zr-10Al-5Ti-17.9Cu-14.6Ni amorphous alloy SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID SUPERCOOLED LIQUID REGION; MECHANICAL-PROPERTIES; METALLIC GLASSES; SLIDING FRICTION; WEAR BEHAVIOR; HIGH-STRENGTH; NI ALLOYS; COATINGS; PARTICLES; EXTRUSION AB The tribological behavior of a Zr-10Al-5Ti-17.9Cu-14.6Ni (at.%) bulk amorphous alloy, in both the as-cast and annealed states, was investigated using nano-scratch tests, including ramping load scratch and multiple sliding wear techniques. The crystallization sequence of the alloy was also characterized. Mechanical properties, such as Young's modulus, hardness, friction coefficient, and tribological wear were measured. These properties were found to vary with microstructure. In general, an increase in annealing temperature results in an increase in hardness, which in turn produces a decrease in friction coefficient but an increase in wear resistance. Samples having a structure consisting of supercooled liquid matrix with dispersed nanocrystalline particles exhibit the best wear performance. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Wang, JG (reprint author), Univ Calif Irvine, Dept Chem & Biochem Engn & Mat Sci, 916 Engn Tower, Irvine, CA 92697 USA. RI Nieh, Tai-Gang/G-5912-2011 OI Nieh, Tai-Gang/0000-0002-2814-3746 NR 52 TC 60 Z9 62 U1 2 U2 19 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 APR PY 2000 VL 15 IS 4 BP 913 EP 922 DI 10.1557/JMR.2000.0130 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA 302MH UT WOS:000086368700013 ER PT J AU Hu, MZC Zielke, JT Byers, CH Lin, JS Harris, MT AF Hu, MZC Zielke, JT Byers, CH Lin, JS Harris, MT TI Probing the early-stage/rapid processes in hydrolysis and condensation of metal alkoxides SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID DIFFUSION-LIMITED AGGREGATION; TITANIUM ALKOXIDES; ZIRCONIUM; OXIDES; SCATTERING; MORPHOLOGY; KINETICS; RANGE AB Understanding and control of the early-stage sol-gel reaction processes involving metal alkoxides are important to many advanced materials development and applications. In this work, Fourier transform infrared spectroscopy (FTIR) and small angle X-ray scattering (SAXS) were coupled with a specially designed, rapid flow-through mixing cell for monitoring such processes. The rapid, early-stage hydrolysis and condensation of zirconium n-butoxide in ethanol were chosen as the basis for a model system. FTIR was used to study soluble-species reaction kinetics, while the SAXS technique monitored in situ the solid-phase particle formation/growth (i.e., the nucleation and aggregation kinetics of polymeric clusters/particles). Monitoring the reactions and cluster/particle growth within a millisecond time regime was achieved. In addition, key parameters such as reaction time, concentration of base (i.e., quarternary tetramethyl ammonium hydroxide), temperature, water concentration, and alkoxide concentration were fully investigated in a continuous flow-through reactor. (C) 2000 Kluwer Academic Publishers. C1 Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ Maryland, Dept Chem Engn, College Pk, MD 20742 USA. RP Hu, MZC (reprint author), Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. OI Hu, Michael/0000-0001-8461-9684 NR 41 TC 26 Z9 27 U1 0 U2 14 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 APR PY 2000 VL 35 IS 8 BP 1957 EP 1971 DI 10.1023/A:1004722603945 PG 15 WC Materials Science, Multidisciplinary SC Materials Science GA 289LQ UT WOS:000085623200014 ER PT J AU Hou, PY AF Hou, PY TI Sulfur segregation to growing Al2O3/alloy interfaces SO JOURNAL OF MATERIALS SCIENCE LETTERS LA English DT Article ID INTERGRANULAR FRACTURE; METAL INTERFACE; OXIDE; ADHERENCE; OXIDATION C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Hou, PY (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 16 TC 29 Z9 30 U1 1 U2 6 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 APR PY 2000 VL 19 IS 7 BP 577 EP 578 DI 10.1023/A:1006774111370 PG 2 WC Materials Science, Multidisciplinary SC Materials Science GA 297HV UT WOS:000086077600013 ER PT J AU Wolfenden, A Mcdaniels, DM Vaidya, RU AF Wolfenden, A Mcdaniels, DM Vaidya, RU TI Temperature dependence of dynamic Young's modulus and mechanical damping in SCS-6/Beta-21S titanium metal matrix composites SO JOURNAL OF MATERIALS SCIENCE LETTERS LA English DT Article C1 Texas A&M Univ, Dept Mech Engn, College Stn, TX 77843 USA. Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Wolfenden, A (reprint author), Texas A&M Univ, Dept Mech Engn, College Stn, TX 77843 USA. NR 9 TC 0 Z9 0 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 APR PY 2000 VL 19 IS 7 BP 595 EP 599 DI 10.1023/A:1006786430026 PG 5 WC Materials Science, Multidisciplinary SC Materials Science GA 297HV UT WOS:000086077600018 ER PT J AU Lara-Curzio, E Singh, M AF Lara-Curzio, E Singh, M TI High-temperature interlaminar shear strength of Hi-Nicalon (TM) fiber-reinforced MI-SiC matrix composites with BN/SiC fiber coating SO JOURNAL OF MATERIALS SCIENCE LETTERS LA English DT Article C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Lara-Curzio, E (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. NR 11 TC 1 Z9 2 U1 2 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 APR PY 2000 VL 19 IS 8 BP 657 EP 661 DI 10.1023/A:1006702409475 PG 5 WC Materials Science, Multidisciplinary SC Materials Science GA 303HW UT WOS:000086417300009 ER PT J AU Lin, GG Gao, HJ Duan, JQ Ervin, VJ AF Lin, GG Gao, HJ Duan, JQ Ervin, VJ TI Asymptotic dynamical difference between the nonlocal and local Swift-Hohenberg models SO JOURNAL OF MATHEMATICAL PHYSICS LA English DT Article ID CENTER MANIFOLD; CONVECTION; EQUATION AB In this paper the difference in the asymptotic dynamics between the nonlocal and local two-dimensional Swift-Hohenberg models is investigated. It is shown that the bounds for the dimensions of the global attractors for the nonlocal and local Swift-Hohenberg models differ by an absolute constant, which depends only on the Rayleigh number, and upper and lower bounds of the kernel of the nonlocal nonlinearity. Even when this kernel of the nonlocal operator is a constant function, the dimension bounds of the global attractors still differ by an absolute constant depending on the Rayleigh number. (C) 2000 American Institute of Physics. [S0022-2488(00)01204-4]. C1 Clemson Univ, Dept Math Sci, Clemson, SC 29634 USA. Inst Appl Phys & Computat Math, Lab Computat Phys, Beijing 100088, Peoples R China. Natl Univ Singapore, Dept Math, Singapore 119260, Singapore. Yunnan Univ, Dept Math, Kunming 650091, Peoples R China. Chinese Acad Engn, Grad Sch, Beijing 100088, Peoples R China. Inst Math & Applicat, Minneapolis, MN USA. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. RP Duan, JQ (reprint author), Clemson Univ, Dept Math Sci, Clemson, SC 29634 USA. OI Gao, Hongjun/0000-0002-5111-1179 NR 17 TC 12 Z9 15 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0022-2488 J9 J MATH PHYS JI J. Math. Phys. PD APR PY 2000 VL 41 IS 4 BP 2077 EP 2089 DI 10.1063/1.533228 PG 13 WC Physics, Mathematical SC Physics GA 296ZL UT WOS:000086056600030 ER PT J AU Bruggemann, J Stephen, JR Chang, YJ Macnaughton, SJ Kowalchuk, GA Kline, E White, DC AF Bruggemann, J Stephen, JR Chang, YJ Macnaughton, SJ Kowalchuk, GA Kline, E White, DC TI Competitive PCR-DGGE analysis of bacterial mixtures an internal standard and an appraisal of template enumeration accuracy SO JOURNAL OF MICROBIOLOGICAL METHODS LA English DT Article DE DGGE; competition; 16S rDNA; culture-independent enumeration ID GRADIENT GEL-ELECTROPHORESIS; 16S RIBOSOMAL-RNA; POLYMERASE CHAIN-REACTION; MICROBIAL-POPULATIONS; DNA FRAGMENTS; GENES; AMPLIFICATION; COMMUNITIES; RDNA; QUANTIFICATION AB Analysis of polymerase chain reaction (PCR) amplified 16S rDNA fragments from environmental samples by denaturing gradients of chemicals or heat [denaturing gradient gel electrophoresis (DGGE) and thermal gradient gel electrophoresis (TGGE)] within polyacrylamide gels is a popular tool in microbial ecology. Difficulties in acceptance of the technique and interpretation of the results remain, due to its qualitative nature. In this study we have addressed this problem by the construction and evaluation of a quantitative standard for incorporation into test DNA samples. The standard was based on a naturally occurring 16S rRNA gene carried by the X-endosymbiont of the psyllid Anomoneura mori, a gamma-proteobacterium. This sequence is the most AT-rich 16S rDNA gene recovered from any cultured organism or environmental sample described to date, and a specifically amplified rDNA fragment denatured under exceptionally low stringency denaturing conditions. The native sequence was modified to incorporate perfect matches to the PCR primers used. The efficiency of amplification of this standard in comparison to a range of 16S rDNA sequences and the errors involved in enumerating template molecules under a range of PCR conditions are demonstrated and quantified. Tests indicated that highly accurate counts of released target molecules from a range of bacterial cells could be achieved in both laboratory mixtures and compost. (C) 2000 Published by Elsevier Science B.V. C1 Univ Tennessee, Ctr Environm Biotechnol, Knoxville, TN 37932 USA. Microbial Insights Inc, Rockford, TN 37853 USA. Netherlands Inst Ecol, NL-6666 ZG Heteren, Netherlands. Oak Ridge Natl Lab, Div Biol Sci, Oak Ridge, TN 37831 USA. RP Stephen, JR (reprint author), Univ Tennessee, Ctr Environm Biotechnol, 10515 Res Dr,Suite 300, Knoxville, TN 37932 USA. RI Kowalchuk, George/C-4298-2011 NR 39 TC 51 Z9 56 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-7012 J9 J MICROBIOL METH JI J. Microbiol. Methods PD APR PY 2000 VL 40 IS 2 BP 111 EP 123 DI 10.1016/S0167-7012(99)00126-8 PG 13 WC Biochemical Research Methods; Microbiology SC Biochemistry & Molecular Biology; Microbiology GA 294WZ UT WOS:000085934600001 PM 10699667 ER PT J AU Ree, FH Viecelli, JA van Thiel, M AF Ree, FH Viecelli, JA van Thiel, M TI Influence of fluorine chemistry on supercritical fluid-fluid phase separations SO JOURNAL OF MOLECULAR LIQUIDS LA English DT Article; Proceedings Paper CT EMLG Conference on Physics of Liquids - Foundations, Highlights, Challenges CY SEP 11-16, 1998 CL MURAU, AUSTRIA SP European Molec Liquids Grp ID DETONATION PROPERTIES; MIXTURES AB Currently available studies on supercritical fluid phase separations are limited to chemically nonreactive systems at low pressure. The present study is concerned with a possible influence of chemical reactions on a supercritical phase change above 1 Cpa. We will first give a brief review of statistical mechanical theory, which is designed to handle chemically reactive systems, as used in this work. We next apply the theoretical formulation to chemically reactive systems containing species composed of C, H, N, O, F atoms. These systems produce mixtures such as CO, CO2, H2O, N-2, HF, etc. Our earlier calculations [1] without F atoms predicted that these molecular systems separate into an N-2-rich and an N-2-poor fluid phases at high pressure and high temperature. This prediction has been experimentally confirmed in part for a N-2+H2O mixture [2]. Addition of F atoms complicates the chemical equilibrium, as the chemical species can react with ii or C atoms to produce HF and CF4 The chemical equilibrium calculations described below predict that fluorine occurs mostly as HF in the N-2-poor phase up to a certain pressure, beyond which it appears mostly as a constituent in CF4 in the N-2-rich phase. But the shift in fluorine chemistry is sensitive to intermolecular potentials involving HF and can be abrupt in thermodynamic sense, thereby enhancing the character of the N-2-fluid phase change. Relevance of the present prediction to detonation properties of high explosives containing fluorine binders is discussed. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Ree, FH (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94550 USA. NR 11 TC 6 Z9 6 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-7322 J9 J MOL LIQ JI J. Mol. Liq. PD APR PY 2000 VL 85 IS 1-2 SI SI BP 229 EP 236 DI 10.1016/S0167-7322(99)00182-8 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 308YB UT WOS:000086739500021 ER PT J AU Ding, YS Logan, J Bermel, R Garza, V Rice, O Fowler, JS Volkow, ND AF Ding, YS Logan, J Bermel, R Garza, V Rice, O Fowler, JS Volkow, ND TI Dopamine receptor-mediated regulation of striatal cholinergic activity: Positron emission tomography studies with norchloro[F-18]fluoroepibatidine SO JOURNAL OF NEUROCHEMISTRY LA English DT Article DE nicotinic acetylcholine receptors; dopamine D-2 receptor; dopamine D-1 receptor; epibatidine; fluorine-18; positron emission tomography ID NICOTINIC ACETYLCHOLINE-RECEPTORS; BABOON BRAIN; IN-VIVO; D-2 RECEPTORS; RAT STRIATUM; RELEASE; BINDING; INVIVO; PET; D1 AB Large numbers of in vitro studies and microdialysis studies suggest that dopaminergic regulation of striatal acetylcholine (ACh) output is via inhibitory dopamine D-2 receptors and stimulatory dopamine D-1 receptors. Questions remain as to the relative predominance of dopamine D-2 versus D-1 receptor modulation of striatal ACh output under physiological conditions. Using positron emission tomography, we first demonstrate that norchloro[F-18]fluoroepibatidine ([F-18]NFEP), a selective nicotinic ACh receptor (nAChR) ligand, was sensitive to changes of striatal ACh concentration. We then examined the effect of quinpirole (D-2 agonist), raclopride (D-2 antagonist) SKF38393 (D-1 agonist), and SCH23390 (D-1 antagonist) on striatal binding of [F-18]NFEP in the baboon. Pretreatment with quinpirole increased the striatum (ST) to cerebellum (CB) ratio by 26 +/- 6%, whereas pretreatment with raclopride decreased the ST/CB ratio by 22 +/- 2%. The ratio of the distribution volume of [F-18]NFEP in striatum to that in cerebellum which corresponds to (B-max/K-D) + 1 (index for nAChR availability), also showed a significant increase (29 and 20%; n = 2) and decrease (20 +/- 3%; n = 3) after pretreatment with quinpirole and raclopride, respectively. However, both the D-1 agonist and antagonist had no significant effect. This suggests that under physiological conditions the predominant influence of endogenous dopamine on striatal ACh output is dopamine D-2, not D-1, receptor-mediated. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. SUNY Stony Brook, Hlth Sci Ctr, Dept Psychiat, Stony Brook, NY 11794 USA. RP Ding, YS (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. FU NIDA NIH HHS [DA-06278]; NINDS NIH HHS [NS-15380] NR 58 TC 34 Z9 35 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0022-3042 J9 J NEUROCHEM JI J. Neurochem. PD APR PY 2000 VL 74 IS 4 BP 1514 EP 1521 DI 10.1046/j.1471-4159.2000.0741514.x PG 8 WC Biochemistry & Molecular Biology; Neurosciences SC Biochemistry & Molecular Biology; Neurosciences & Neurology GA 295DL UT WOS:000085951400021 PM 10737608 ER PT J AU Allen, TR Kenik, EA Was, GS AF Allen, TR Kenik, EA Was, GS TI Variability of radiation-induced segregation in iron-chromium-nickel alloys SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID GRAIN-BOUNDARY SEGREGATION; AUSTENITIC STAINLESS-STEELS; ELECTRON-IRRADIATION; DEPENDENCE AB This work examines the variability in grain boundary segregation measurements in proton irradiated iron-chromium-nickel alloys made using Anger electron spectroscopy (AES) and scanning transmission electron microscopy with energy dispersive X-ray spectroscopy (STEM-EDS). Variability occurs in segregation measurements made on different boundaries in the same sample and made on different samples irradiated under the same conditions. Variability occurs in each measurement technique, but is greater for AES. A portion of the greater variability in the AES measurements occurs because only the concentrations calculated from AES measurements are sensitive to changes in the shape of the energy intensity peak. A statistical analysis technique for testing the consistency of experimental conditions demonstrated that the variability is not attributable to uncertainty in irradiation temperature, dose, or material condition. Finally, the analysis of grain boundary composition distributions in Fe-20Cr-9Ni indicates that attempts to minimize environmental cracking by controlling grain boundary composition need to focus on both the average grain boundary compositions and the shape of the concentration distributions. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab W, Idaho Falls, ID 83403 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. Univ Michigan, Dept Nucl Engn & Radiol Sci, Ann Arbor, MI 48109 USA. RP Allen, TR (reprint author), Argonne Natl Lab W, POB 2528, Idaho Falls, ID 83403 USA. OI Allen, Todd/0000-0002-2372-7259 NR 19 TC 1 Z9 1 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD APR PY 2000 VL 278 IS 2-3 BP 149 EP 163 DI 10.1016/S0022-3115(99)00263-9 PG 15 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 291FK UT WOS:000085723300003 ER PT J AU Inal, MY Alam, M Kurz, K Cowgill, DF Causey, RA AF Inal, MY Alam, M Kurz, K Cowgill, DF Causey, RA TI Retention and release of deuterium implanted in copper coatings on Al-6061 SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID METALS; ALUMINUM AB To mitigate the problem of retention and permeation of tritium implanted in Al-6061, the use of copper coatings was investigated. Copper coatings (having weights of 0.03, 0.06 and 0.088 kg/m(2)) deposited on Al-6061 substrates by the RF Magnetron sputtering method were implanted with deuterium (D) in an accelerator at 350 K, and the resulting D profiles were monitored using negative SIMS and the D(He-3,p)He-4 nuclear reaction. The retention characteristics of deuterium were subsequently studied as a function of coating weight, D+ fluence (varied in the 1 - 3 x 10(21) D+/m(2) range) and D+ ion energy (40 and 120 keV). Under identical implantation conditions, deuterium retention in Al-6061 was higher than in Al-6061 coated with 0.088 kg/m(2) Cu. In the various coatings implanted under different conditions, deuterium retention ranged between 1.2% and 5.4% of the implanted amount. The deuterium retention decreased with increasing coating weight and then leveled off with further increases in the coating weight. The retention increased linearly with implantation fluence, (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 New Mexico Inst Min & Technol, Dept Mat & Met Engn, Socorro, NM 87801 USA. Sandia Natl Labs, Livermore, CA 94550 USA. RP Alam, M (reprint author), New Mexico Inst Min & Technol, Dept Mat & Met Engn, 801 Leroy Pl, Socorro, NM 87801 USA. NR 26 TC 3 Z9 3 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD APR PY 2000 VL 278 IS 2-3 BP 164 EP 172 DI 10.1016/S0022-3115(99)00262-7 PG 9 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 291FK UT WOS:000085723300004 ER PT J AU Aglan, HA Gan, YX Chin, BA Grossbeck, ML AF Aglan, HA Gan, YX Chin, BA Grossbeck, ML TI Effect of composition on the fatigue failure behavior of vanadium alloys SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID DEFORMATION-BEHAVIOR; CRACK-PROPAGATION; GRAIN-BOUNDARIES; SINGLE-CRYSTALS; CYCLE FATIGUE; SLIP; MICROSTRUCTURE; TOUGHNESS; STEEL AB In this work, the effect of composition on the fracture surface morphology and fatigue failure behavior of two vanadium alloys (V-4Ti-4Cr and V-5Ti-5Cr) under cyclic tensile loading was investigated. In the beginning of the stable crack growth stage, the crack speed for both vanadium alloys is very close; however, in the remainder of the stable crack growth stage, and the unstable crack stage, the crack speed for V-5Ti-5Cr is higher than that for V-4Ti-4Cr. The fracture surface features in the stable crack propagation region of the V-4Ti-4Cr show fatigue striations, drawn-out material, micro-cracks and micro-voids, indicating the various damage species associated with stable fatigue crack growth. The V-5Ti-5Cr, on the other hand, displayed twinning, cleavage tongues and tearing steps, in addition to slip in the stable crack propagation region of its fracture surface. Plastic deformation and ductile fracture mechanisms characterized by tearing and void coalescence can also be observed on the fracture surface in the fast crack region of the V-4Ti-4Cr. Nevertheless, the V-5Ti-5Cr shows more inter-granular fracture and quasi-cleavage features in the fast crack propagation region. It was also found that the specific energy of damage (gamma'), a material parameter characteristic of the alloys' fatigue fracture resistance, is composition dependent. A 1% increase of both the Ti and Cr content resulted in about a 30% reduction in the value of gamma'. This has also resulted in a significant change in the fracture surface morphology and the fatigue fracture mechanisms. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Tuskegee Univ, Dept Engn Mech, Tuskegee, AL 36088 USA. Auburn Univ, Ctr Mat Res & Educ, Auburn, AL 36849 USA. Oak Ridge Natl Lab, Oak Ridge, TN USA. RP Aglan, HA (reprint author), Tuskegee Univ, Dept Engn Mech, Tuskegee, AL 36088 USA. NR 48 TC 7 Z9 10 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD APR PY 2000 VL 278 IS 2-3 BP 186 EP 194 DI 10.1016/S0022-3115(99)00258-5 PG 9 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 291FK UT WOS:000085723300006 ER PT J AU Williford, RE Begg, BD Weber, WJ Hess, NJ AF Williford, RE Begg, BD Weber, WJ Hess, NJ TI Computer simulation of Pu3+ and Pu4+ substitutions in zircon SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID CERAMIC WASTE FORMS; ABSORPTION FINE-STRUCTURE; DOPED GLASS AB Energy minimization methods were used in atomistic computer simulations to determine the energetics of Pu3+ and Pu4+ substitutions and interstitials in zircon, including the effect of ion size. The lowest energy was found for Pu-Zr(4+) substitutions. The lowest energy for Pu3+ substitutions was found for the defect cluster 2Pu(Zr)(3+') + V-O(..). Mean field calculations of unit-cell Volumes for 8% Pu substitutions were in agreement with X-ray diffraction (XRD) data. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. Australian Nucl Sci & Technol Org, Div Mat, Menai, NSW 2234, Australia. RP Williford, RE (reprint author), Pacific NW Natl Lab, POB 999,Mail Stop K2-44, Richland, WA 99352 USA. RI Weber, William/A-4177-2008; OI Weber, William/0000-0002-9017-7365; Hess, Nancy/0000-0002-8930-9500 NR 15 TC 16 Z9 17 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD APR PY 2000 VL 278 IS 2-3 BP 207 EP 211 DI 10.1016/S0022-3115(99)00244-5 PG 5 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 291FK UT WOS:000085723300009 ER PT J AU Begg, BD Hess, NJ Weber, WJ Conradson, SD Schweiger, MJ Ewing, RC AF Begg, BD Hess, NJ Weber, WJ Conradson, SD Schweiger, MJ Ewing, RC TI XAS and XRD study of annealed Pu-238- and Pu-239-substituted zircons (Zr0.92Pu0.08SiO4) SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID CERAMIC WASTE FORMS; PU-DOPED GLASS; METAMICT ZIRCON; NEUTRON-DIFFRACTION; RADIATION-DAMAGE; EXAFS; DIFFUSION; THORITE; PHASE AB An annealing study has been completed on two compositionally identical Pu-substituted zircons (Zr0.92Pu0.08SiO4) prepared 18 yr ago with different Pu-238/Pu-239 isotopic ratios. The activity and accumulated dose for each material varies greatly due to the very different half-lives of Pu-238 (87.7 yr) and Pu-239 (24100 yr). The predominantly Pu-238-substituted zircon is in a highly amorphous state after accumulating a dose of 2.8 x 10(19) alpha-decays/g, which is a factor of two higher than the dose previously determined necessary to amorphize this material. The Pu-239-substituted zircon has remained highly crystalline after an accumulated dose of 1.2 x 10(17) alpha-decays/g. The Pu in both samples is trivalent due to sintering under reducing conditions. The short-range and long-range structures of each sample have been characterized by detailed X-ray absorption spectroscopy and X-ray diffraction (XRD) methods. The oxidation of Pu3+ to Pu4+ the crystalline Pu-239-substituted zircon during annealing in air resulted in a decrease in lattice distortion due to the decrease in ionic radius of Pu3+ to Pu4+ On the Zr4+ site. A significant amount of PuO2 exsolved from the zircon structure after annealing at 1200 degrees C in air. Detailed characterization of the amorphous Pu-238-substituted zircon demonstrated that while devoid of long-range order it still retained a distorted zircon structure and composition over a length scale of 0.5 nm. The recrystallization of the amorphous Pu-238-substituted zircon could be achieved directly at temperatures as low as 1200 degrees C when annealed for 12 h in air; however, annealing at 1000 degrees C resulted in decomposition into constituent oxides. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Pacific NW Lab, Richland, WA 99352 USA. Australian Nucl Sci & Technol Org, Menai, NSW 2234, Australia. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Michigan, Dept Nucl Engn & Radiol Sci, Ann Arbor, MI 48109 USA. RP Weber, WJ (reprint author), Pacific NW Lab, POB 999, Richland, WA 99352 USA. RI Weber, William/A-4177-2008; OI Weber, William/0000-0002-9017-7365; Hess, Nancy/0000-0002-8930-9500 NR 29 TC 34 Z9 35 U1 2 U2 13 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD APR PY 2000 VL 278 IS 2-3 BP 212 EP 224 DI 10.1016/S0022-3115(99)00256-1 PG 13 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 291FK UT WOS:000085723300010 ER PT J AU Devanathan, R Weber, WJ AF Devanathan, R Weber, WJ TI Displacement energy surface in 3C and 6H SiC SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID MOLECULAR-DYNAMICS; SILICON-CARBIDE; INTERATOMIC POTENTIALS; DEFECTS; DAMAGE AB The phase stability of 3C-SiC upon heating and the threshold displacement energy (E-d) surfaces for C and Si primary knock-on atoms (PKAs) in 3C-SiC and 6H-SiC have been investigated using molecular dynamics simulations. A recently optimized Tersoff potential is used in conjunction with an ab initio repulsive potential to represent the interactions between atoms. The simulations provide important insights into phase separation of SiC upon heating, and indicate a strong anisotropy in the E-d surface for both Si and C PKAs. The two polytypes show many similarities in the nature of the E-d surface. The average displacement energy is separately determined by simulating 30 different 500 eV cascades in 3C-SiC. The minimum displacement energies of 21 eV for C and 35 eV for Si are in excellent agreement with interpretation of experimental observations and the simulations of 500 eV cascades. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. Indian Inst Technol, Dept Met Engn, Madras 600036, Tamil Nadu, India. RP Weber, WJ (reprint author), Pacific NW Natl Lab, MSIN K2-44,POB 999, Richland, WA 99352 USA. RI Weber, William/A-4177-2008; Devanathan, Ram/C-7247-2008 OI Weber, William/0000-0002-9017-7365; Devanathan, Ram/0000-0001-8125-4237 NR 28 TC 129 Z9 130 U1 3 U2 40 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD APR PY 2000 VL 278 IS 2-3 BP 258 EP 265 DI 10.1016/S0022-3115(99)00266-4 PG 8 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 291FK UT WOS:000085723300015 ER PT J AU Lee, EH Hunn, JD Hashimoto, N Mansur, LK AF Lee, EH Hunn, JD Hashimoto, N Mansur, LK TI Hardness and defect structures in EC316LN austenitic alloy irradiated under a simulated spallation neutron source environment using triple ion-beams SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID STAINLESS-STEELS; MICROSTRUCTURAL EVOLUTION; DOSE DEPENDENCE; TEMPERATURE; INDENTATION; MECHANISMS; HELIUM; LOAD AB For an assessment of the future US spallation neutron source (SNS) target performance, radiation induced hardening and microstructural evolution were investigated as a function of ion dose for EC316LN stainless steel. Irradiation was carried out using 3.5 MeV Fe+, 360 keV He+, and 180 keV H+ simultaneous ion-beams at 200 degrees C to simulate the damage, He and H production in the SNS target vessel wall, At low dose (< dpa), the predominant defects were black dots whose number density saturated rapidly within a few dpa. This was followed by the evolution of interstitial loops whose number density saturated below 15 dpa. Although He-bubbles were not visible, severely scalloped loops suggested that the implanted He/H atoms existed in the form of small clusters. Comparison with reported neutron irradiation data showed that hardening and ductility loss occurred mostly in the black dot regime (<1 dpa), but that good ductility (>20% elongation) was maintained up to a dose level of similar or equal to 10 dpa. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Lee, EH (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. RI HASHIMOTO, Naoyuki/D-6366-2012 NR 34 TC 18 Z9 19 U1 1 U2 13 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD APR PY 2000 VL 278 IS 2-3 BP 266 EP 272 DI 10.1016/S0022-3115(99)00239-1 PG 7 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 291FK UT WOS:000085723300016 ER PT J AU Lillard, RS Pile, DL Butt, DP AF Lillard, RS Pile, DL Butt, DP TI The corrosion of materials in water irradiated by 800 MeV protons SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article AB A method for measuring the real-time corrosion rates for Alloy 718, stainless steels (SS) 304L and 316L nuclear grade (NG), aluminum alloys 5052 (Al5052) and 6061 (Al6061), copper (Cu), tantalum (Ta), and tungsten (W) in two separate water systems that were irradiated by 800 MeV protons is presented. The first water system was fabricated entirely of 304 SS, thoroughly cleaned before operation, and employed hydrogen water chemistry (HWC) to mitigate the formation of some of the radiolysis products. The samples were adequately shielded from the irradiation cavity such that only the effects of water chemistry were investigated. Over the course of that irradiation period the corrosion rates for 304L SS, 316L-NG SS, Ahoy 718, and Ta were less than 0.12 mu m/yr. For Al6061 and Al5052, the corrosion rates were of the order of 0.50-2.0 mu m/yr. The corrosion rate of W was relatively high between 5.0 and 30 mu m/yr. The second water system, fabricated from copper piping and steel components, was not cleaned prior to operation, and employed no HWC. In comparison to the other system, the corrosion rates in the copper/steel system were 1-3 orders of magnitude higher. These results are discussed in terms of water radiolysis and water impurity levels. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Mat Corros & Environm Effects Lab, Los Alamos, NM 87545 USA. RP Lillard, RS (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Mat Corros & Environm Effects Lab, MST-6,POB 1663,MS G775, Los Alamos, NM 87545 USA. RI Butt, Darryl/B-7480-2008 OI Butt, Darryl/0000-0003-4501-8864 NR 26 TC 15 Z9 15 U1 0 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD APR PY 2000 VL 278 IS 2-3 BP 277 EP 289 DI 10.1016/S0022-3115(99)00248-2 PG 13 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 291FK UT WOS:000085723300018 ER PT J AU Burns, PC Olson, RA Finch, RJ Hanchar, JM Thibault, Y AF Burns, PC Olson, RA Finch, RJ Hanchar, JM Thibault, Y TI KNa3(UO2)2(Si4O10)2(H2O)(4), a new compound formed during vapor hydration of an actinide-bearing borosilicate waste glass SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID NUCLEAR; MECHANISMS; MINERALS; SURFACE; PHASES AB Vapor hydration experiments on a U-doped borosilicate waste glass at 200 degrees C produced a novel uranium silicate. Single crystal X-ray structure analysis of this phase indicate the ideal formula KNa3(UO2)(2)(Si4O10)(2)(H2O)(4), although the compound shows some compositional variability. It is monoclinic, space group C2, Z = 2, a = 1.2782(1), b = 1.3654(1), c = 0.82677(8) nm, beta = 119.240(1)degrees. The structure was solved by direct methods and refined to an agreement index (R) of 3.6% for 2239 unique observed (\F-0\ greater than or equal to 4 sigma(F)) reflections and a goodness-of-fit of 1.05. The structure contains vertex-sharing silicate tetrahedra arranged in four and eight-membered rings that are linked to give sheets parallel to (0 0 1). The sheets are cross-linked by vertex-sharing with UrO(4) square bipyramids [Ur = (UO2)(2+) uranyl ion], forming a framework of polyhedra of higher bond-valence. The title phase is the major sink for U during glass corrosion at 200 degrees C after approximately 60 days in a saturated vapor environment. Consideration of the structural sites reveals the potential of this compound to incorporate radionuclides from a variety of nuclear-waste glasses over a wide range of environmental conditions. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Notre Dame, Dept Civil Engn & Geol Sci, Notre Dame, IN 46556 USA. Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. Univ Western Ontario, Dept Earth Sci, London, ON N6A 5B7, Canada. RP Burns, PC (reprint author), Univ Notre Dame, Dept Civil Engn & Geol Sci, 156 Fitzpatrick, Notre Dame, IN 46556 USA. RI Finch, Robert/D-9553-2013; Burns, Peter/J-3359-2013; OI Finch, Robert/0000-0001-9342-5574; Burns, Peter/0000-0002-2319-9628 NR 18 TC 63 Z9 63 U1 0 U2 15 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD APR PY 2000 VL 278 IS 2-3 BP 290 EP 300 DI 10.1016/S0022-3115(99)00247-0 PG 11 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 291FK UT WOS:000085723300019 ER PT J AU Meyer, MK Wiencek, TC Hayes, SL Hofman, GL AF Meyer, MK Wiencek, TC Hayes, SL Hofman, GL TI Irradiation behavior of U6Mn-Al dispersion fuel elements SO JOURNAL OF NUCLEAR MATERIALS LA English DT Letter ID URANIUM AB Irradiation testing of U6Mn-Al dispersion fuel miniplates was conducted in the Oak Ridge Research Reactor (ORR). Post-irradiation examination showed that U6Mn in an unrestrained plate configuration performs similarly to U6Fe under irradiation, forming extensive and interlinked fission gas bubbles at a fission density of approximately 3 x 10(27) m(-3). Fuel plate failure occurs by fission gas pressure driven 'pillowing' on continued irradiation. Published by Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab W, Idaho Falls, ID 83404 USA. Argonne Natl Lab E, Argonne, IL 60439 USA. RP Meyer, MK (reprint author), Argonne Natl Lab W, POB 2528, Idaho Falls, ID 83404 USA. RI Hayes, Steven/D-8373-2017; OI Hayes, Steven/0000-0002-7583-2069; Meyer, Mitchell/0000-0002-1980-7862 NR 9 TC 16 Z9 16 U1 5 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD APR PY 2000 VL 278 IS 2-3 BP 358 EP 363 DI 10.1016/S0022-3115(99)00280-9 PG 6 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 291FK UT WOS:000085723300026 ER PT J AU Tibbitts, J Sambol, NC Fike, JR Bauer, WF Kahl, SB AF Tibbitts, J Sambol, NC Fike, JR Bauer, WF Kahl, SB TI Plasma pharmacokinetics and tissue biodistribution of boron following administration of a boronated porphyrin in dogs SO JOURNAL OF PHARMACEUTICAL SCIENCES LA English DT Article DE boron; boron neutron capture therapy; photodynamic therapy; pharmacokinetics; dog; boronated porphyrin ID NEUTRON-CAPTURE THERAPY; PHOTODYNAMIC THERAPY; INTRACRANIAL TUMORS; CEREBRAL GLIOMA; ANIMAL-MODEL; PHOTOSENSITIZER; PROTEINS; MICE AB This study was undertaken to determine the plasma pharmacokinetics and tissue biodistribution of boron in dogs following the administration of a boronated porphyrin (BOPP) compound, a potential sensitizing agent for binary therapies of cancer. An intravenous dose of 35 mg/kg of BOPP was administered to a total of sixteen dogs and plasma samples obtained at multiple time points for up to 28 days after administration. Groups of four dogs each were studied for 25, 79, 240, and 672 h. At the end of each study period, subjects were sacrificed and tissue samples obtained. Boron concentrations were determined for all tissue and plasma samples, and pharmacokinetic parameters were determined using mixed effects modeling. Plasma boron levels displayed triexponential kinetics with a long terminal half-life and small volume of distribution. Liver, lymph node, adrenal, and kidney tissues accumulated the highest levels of boron, with very low levels associated with most tissues of the head. We conclude that BOPP has pharmacokinetic and tissue distribution properties that suggest that it may be a suitable compound for use as a sensitizing agent in binary therapy of cancer. (C) 2000 Wiley-Liss, and the American Pharmaceutical Association J Pharm Sci 89:469-477, 2000. C1 Univ Calif San Francisco, Sch Pharm, Dept Pharmaceut Chem, San Francisco, CA 94143 USA. Univ Calif San Francisco, Sch Pharm, Dept Biopharmaceut Sci, San Francisco, CA 94143 USA. Univ Calif San Francisco, Brain Tumor Res Ctr, Dept Neurol Surg, San Francisco, CA 94143 USA. Idaho Natl Lab, Natl Ctr BNCT Measurement & Dev, Idaho Falls, ID 83415 USA. RP Tibbitts, J (reprint author), Univ Calif San Francisco, Sch Pharm, Dept Pharmaceut Chem, San Francisco, CA 94143 USA. EM sbkahl@itsa.ucsf.edu RI Bauer, William/B-8357-2016 OI Bauer, William/0000-0002-7190-9700 FU NCI NIH HHS [CA13525, CA37961] NR 29 TC 15 Z9 17 U1 0 U2 3 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0022-3549 J9 J PHARM SCI-US JI J. Pharm. Sci. PD APR PY 2000 VL 89 IS 4 BP 469 EP 477 DI 10.1002/(SICI)1520-6017(200004)89:4<469::AID-JPS4>3.0.CO;2-6 PG 9 WC Chemistry, Medicinal; Chemistry, Multidisciplinary; Pharmacology & Pharmacy SC Pharmacology & Pharmacy; Chemistry GA 304EU UT WOS:000086470700004 PM 10737908 ER PT J AU Yokel, RA Fredenburg, AM Durbin, PW Xu, JD Rayens, MK Raymond, KN AF Yokel, RA Fredenburg, AM Durbin, PW Xu, JD Rayens, MK Raymond, KN TI The hexadentate hydroxypyridinonate TREN-(Me-3,2-HOPO) is a more orally active iron chelator than its bidentate analogue SO JOURNAL OF PHARMACEUTICAL SCIENCES LA English DT Article ID ION SEQUESTERING AGENTS; IN-VIVO CHELATION; MULTIDENTATE CATECHOLATE; LIGANDS; THALASSEMIA; MICE; 1,2-DIMETHYL-3-HYDROXYPYRID-4-ONE; DESFERRIOXAMINE; DEFEROXAMINE; MOBILIZATION AB Bidentate hydroxypyridinone chelators effectively complex and facilitate excretion of trivalent iron. To test the hypothesis that hexadentate chelators are more effective than bidentate chelators at low concentrations, urinary and biliary Fe excretions were determined in Fe-loaded rats before and after administration of a bidentate chelator, Pr-(Me-3,2-HOPO), or its hexadentate analogue, TREN-(Me-3,2-HOPO). The bidentate chelator slightly increased biliary Fe excretion in Fe-loaded rats after IV (90 mu mol/kg) and PO (90 or 270 mu mol/kg) administration, but chelation efficiency did not exceed 1%. The hexadentate chelator markedly increased biliary Fe excretion, achieving overall chelation efficiencies of 14% after IV administration of 30 mu mol/kg and 8 or 3% after PO (30 or 90 mu mol/kg) administration. The hexadentate chelator was significantly more effective than the bidentate chelator after IV injection and oral dosing. In chelator-treated Fe-loaded or saline-injected rats, >90% of the excreted Fe was in the bile. Oral TREN-(Me-3,2-HOPO), given to non-Fe-loaded rats, did not appreciably change Fe output, indicating that there was little Fe depletion in the absence of Fe overload. These results support the hypothesis that greater Fe chelation efficiency can be achieved with hexadentate than with bidentate chelators at lower, and presumably safer, concentrations. The results also demonstrate that TREN-(Me-3,2-HOPO) is a promising, orally effective, Fe chelator. (C) 2000 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 89: 545-555, 2000. C1 Univ Kentucky, Med Ctr, Coll Pharm, Lexington, KY 40536 USA. Univ Kentucky, Grad Ctr Toxicol, Lexington, KY 40536 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Kentucky, Biostat Consulting Unit, Lexington, KY 40536 USA. RP Yokel, RA (reprint author), Univ Kentucky, Med Ctr, Coll Pharm, Rose St, Lexington, KY 40536 USA. FU NIDDK NIH HHS [DK32999] NR 40 TC 35 Z9 35 U1 3 U2 6 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0022-3549 J9 J PHARM SCI JI J. Pharm. Sci. PD APR PY 2000 VL 89 IS 4 BP 545 EP 555 DI 10.1002/(SICI)1520-6017(200004)89:4<545::AID-JPS12>3.0.CO;2-J PG 11 WC Chemistry, Medicinal; Chemistry, Multidisciplinary; Pharmacology & Pharmacy SC Pharmacology & Pharmacy; Chemistry GA 304EU UT WOS:000086470700012 PM 10737916 ER PT J AU Lenaghan, JT Rischke, DH AF Lenaghan, JT Rischke, DH TI The O(N) model at nonzero temperature: renormalization of the gap equations in Hartree and large-N approximations SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Article ID CHIRAL PHASE-TRANSITION; LINEAR SIGMA-MODEL; FINITE-TEMPERATURE; LAMBDA-PHI(4) THEORY; SYMMETRY BEHAVIOR; GAUGE-THEORIES; FIELD-THEORY; RESUMMATION AB The temperature dependence of the sigma meson and pion masses is studied in the framework of the O(N) model. The Cornwall-Jackiw-Tomboulis formalism is applied to derive gap equations for the masses in the Hartree and large-N approximations. Renormalization of the gap equations is carried out within the cut-off and counter-term renormalization schemes. A consistent renormalization of the gap equations within the cut-off scheme is found to be possible only in the large-N approximation acid for a finite value of the cut-off. On the other hand, the counter-term scheme allows for a consistent renormalization of both the large-N and Hartree approximations. In these approximations, the meson masses at a given nonzero temperature depend in general on the choice of the cut-off or renormalization scale. As an application, we also discuss the in-medium on-shell decay widths for sigma mesons and pions at rest. C1 Yale Univ, Dept Phys, New Haven, CT 06520 USA. Brookhaven Natl Lab, Dept Phys, RIKEN BNL Res Ctr, Upton, NY 11973 USA. RP Lenaghan, JT (reprint author), Yale Univ, Dept Phys, New Haven, CT 06520 USA. NR 35 TC 85 Z9 85 U1 0 U2 1 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 APR PY 2000 VL 26 IS 4 BP 431 EP 450 DI 10.1088/0954-3899/26/4/309 PG 20 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 306KE UT WOS:000086595200011 ER PT J AU Prakash, J Redey, L Vissers, DR AF Prakash, J Redey, L Vissers, DR TI Dynamic performance measurements of Na/NiCl2 cells for electric vehicle applications SO JOURNAL OF POWER SOURCES LA English DT Article DE dynamic performance; batteries; nickel chloride; specific energy; specific power ID SODIUM AB A method to measure the dynamic-performance of sodium/nickel chloride research cells under various dynamic load profiles, such as the Simplified Federal Urban Driving Schedule (SFUDS) has been described. The dynamic performance of various Na/NiCl2 research cells is measured in various power profiles in which the duration, intensity, and ratios of the power levels (mW/cm(2)) in the SFUDS-like profiles are varied. Performance parameters such as area-specific impedance and specific-area energy are obtained by discharging these cells under actual conditions that exist in the full-size battery during the intended applications. The performance parameters measured by this method are employed in relatively simple scale-up calculations to project performances of full-size battery. (C) 2000 Elsevier Science S.A. All rights reserved. C1 IIT, Ctr Electrochem Sci, Chicago, IL 60616 USA. Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. RP Prakash, J (reprint author), IIT, Ctr Electrochem Sci, 10 W 33rd St, Chicago, IL 60616 USA. NR 15 TC 12 Z9 15 U1 1 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0378-7753 J9 J POWER SOURCES JI J. Power Sources PD APR PY 2000 VL 87 IS 1-2 BP 195 EP 200 DI 10.1016/S0378-7753(99)00473-5 PG 6 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA 304DY UT WOS:000086468600025 ER PT J AU Nagasubramanian, G AF Nagasubramanian, G TI Two- and three-electrode impedance studies on 18650 Li-ion cells SO JOURNAL OF POWER SOURCES LA English DT Article DE lithium-ion; impedance AB Two- and three-electrode impedance measurements were made on 18650 Li-ion cells at different temperatures ranging from 35 degrees C to -40 degrees C. The ohmic resistance of the cell is nearly constant in the temperature range studied although the total cell impedance increases by an order of magnitude in the same temperature range. In contrast to what is commonly believed, we show from our three-electrode impedance results that, the increase in cell impedance comes mostly from the cathode and not from the anode. Further, the anode and cathode contribute to both the impedance loops (in the NyQuist plot). (C) 2000 Elsevier Science S.A. All rights reserved. C1 Sandia Natl Labs, Lithium Battery R&D 2521, Albuquerque, NM 87185 USA. RP Nagasubramanian, G (reprint author), Sandia Natl Labs, Lithium Battery R&D 2521, Albuquerque, NM 87185 USA. NR 10 TC 49 Z9 51 U1 4 U2 29 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0378-7753 J9 J POWER SOURCES JI J. Power Sources PD APR PY 2000 VL 87 IS 1-2 BP 226 EP 229 DI 10.1016/S0378-7753(99)00469-3 PG 4 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA 304DY UT WOS:000086468600031 ER PT J AU Albritton, JR Wilson, BG AF Albritton, JR Wilson, BG TI NLTE ionization and energy balance in high-Z laser-plasmas including two-electron transitions SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID SPECTROSCOPY AB We describe a new non-LTE statistical atomic kinetics model of plasmas in which the two-electron transitions of auto-ionization and its inverse, resonant-capture, play a dominant role in establishing ionization and energy balance. We show that, compared with a familiar collisional-radiative-equilibrium model which includes only the one-electron bound-bound and bound-free transitions: (1) the two-electron transitions force recombination of the plasma with decreasing density, (2) the two-electron transitions nevertheless further act to greatly increase the radiative emissivity of the plasma, and (3) the relaxation of the two-electron transition driven sysems proceeds much faster. (C) 2000 Published by Elsevier Science Ltd. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Albritton, JR (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-41, Livermore, CA 94550 USA. NR 12 TC 16 Z9 21 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD APR-MAY PY 2000 VL 65 IS 1-3 BP 1 EP 13 DI 10.1016/S0022-4073(99)00050-3 PG 13 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 275TR UT WOS:000084836700002 ER PT J AU Alexiou, S Lee, RW Glenzer, SH Castor, JI AF Alexiou, S Lee, RW Glenzer, SH Castor, JI TI Analysis of discrepancies between quantal and semiclassical calculations of electron impact broadening in plasmas SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE Coulomb-Bethe approximation; Coulomb-Born methods; electronic impact broadening ID B-III; TRANSITIONS AB In this work we analyse the serious discrepancies found between quantal calculations and non-perturbative semiclassical calculations of electron impact broadening in the case of B(2+)2s-2p. We use the Coulomb Bethe (CB) approximation to calculate both electron impact broadening and excitation of 2s-2p for comparison with the other methods. We find good agreement between CB and the non-perturbative semiclassical method for the line width contributions of individual partial waves, except for low L, where strong collision effects enter. We also find good agreement between CB and the R-matrix and Coulomb Born methods for the excitation cross section partial wave contributions, again except for low L. There is disagreement for the high partial wave cross sections between the non-perturbative semiclassical method and all of the quantum methods; this is resolved by applying a symmetrized method, for which we demonstrate excellent agreement with CB. The area in which the semiclassical, Coulomb-Born and R-matrix methods disagree has been reduced to the first three partial waves, and the disagreement must be due to the treatment of strong collisions. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Lee, RW (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L 399, Livermore, CA 94550 USA. NR 9 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 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD APR-MAY PY 2000 VL 65 IS 1-3 BP 15 EP 22 DI 10.1016/S0022-4073(99)00051-5 PG 8 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 275TR UT WOS:000084836700003 ER PT J AU Aschke, L Depierreux, S Estabrook, KG Fournier, KB Fuchs, J Glenzer, S Lee, RW Rozmus, W Thoe, RS Young, PE AF Aschke, L Depierreux, S Estabrook, KG Fournier, KB Fuchs, J Glenzer, S Lee, RW Rozmus, W Thoe, RS Young, PE TI Towards an experimental benchmark for aluminum X-ray spectra SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID LASER-PRODUCED PLASMAS; SPOT SPECTROSCOPY; TARGETS; TEMPERATURE; RESOLUTION AB To test the validity of kinetics for laser-produced plasmas, one would like to measure the X-ray spectrum emitted from a plasma volume whose characteristics are determined by diagnostics that do not rely on interpreting the X-ray spectrum itself. An experimental test bed has been developed at the Janus laser at Lawrence Livermore National Laboratory to simultaneously characterize the electron temperature, the electron density and the X-ray emission from laser-irradiated aluminum dot targets. Thomson scattering, interferometry and pinhole imaging are implemented to achieve this. Further, the X-ray spectrum from 1-2 keV is spatially integrated and is obtained using a flat crystal (PET) and an X-ray streak camera for time resolution. Spectra have been calculated using the HULLAC and FLY atomic physics codes which use the measured density and temperature as input, and DCA which calculates X-ray spectra from the 2-D expanding plasma calculated by a hydrodynamics code. Comparisons of the models with the data will be discussed and future directions will be indicated. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Ruhr Univ Bochum, D-4630 Bochum, Germany. Ecole Polytech, F-91128 Palaiseau, France. Univ Alberta, Edmonton, AB T6G 2M7, Canada. RP Lee, RW (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-399, Livermore, CA 94550 USA. NR 17 TC 12 Z9 14 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD APR-MAY PY 2000 VL 65 IS 1-3 BP 23 EP 30 DI 10.1016/S0022-4073(99)00052-7 PG 8 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 275TR UT WOS:000084836700004 ER PT J AU Bailey, JE Asay, J Bernard, M Carlson, AL Chandler, GA Hall, CA Hanson, D Johnston, R Lake, P Lawrence, J AF Bailey, JE Asay, J Bernard, M Carlson, AL Chandler, GA Hall, CA Hanson, D Johnston, R Lake, P Lawrence, J TI Optical spectroscopy measurements of shock waves driven by intense z-pinch radiation SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID REFLECTIVITY; DEUTERIUM; ALUMINUM; EQUATION; STATE AB Z-pinches, created using the Z accelerator, generate similar to 220 TW, 1.7 MJ radiation pulses that can heat large (similar to 10(3) cm) hohlraums to 100-150 eV temperatures for times of order 10 ns. We are performing experiments exploiting this intense radiation to drive shock waves for equation of state studies. The shock pressures are typically 1-10 Mbar with 10 ns duration in 6-mm-diameter samples. We demonstrate the ability to perform optical spectroscopy measurements on shocked samples located in close proximity to the z-pinch. These experiments are particularly well suited to optical spectroscopy because of the relatively large sample size and long duration. The optical emission is collected using fiber optics and recorded with a streaked spectrograph. Other diagnostics include VISAR and active shock breakout measurements of the shocked sample and a suite of diagnostics that characterize the radiation drive. Our near term goal is to use the spectral emission to obtain the temperature of the shocked material. Longer term objectives include the examination of deviations of the spectrum from blackbody, line emission from lower density regions, determination of kinetic processes in molecular systems, evaluation of phase transitions such as the onset of metallization in transparent materials, and characterization of the plasma formed when the shock exits the rear surface. An initial set of data illustrating both the potential and the challenge of these measurements is described. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Bailey, JE (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 22 TC 7 Z9 7 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD APR-MAY PY 2000 VL 65 IS 1-3 BP 31 EP 42 DI 10.1016/S0022-4073(99)00053-9 PG 12 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 275TR UT WOS:000084836700005 ER PT J AU Bauche-Arnoult, C Bauche, J Wyart, JF Fournier, KB AF Bauche-Arnoult, C Bauche, J Wyart, JF Fournier, KB TI Effects of the exchange Slater integrals on the shapes of transition arrays SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID ATOMIC SPECTRA; IONIZED ATOMS; CONFIGURATIONS AB Many atomic transition arrays exhibit remarkable shapes. First, some arrays are strongly asymmetrical. Secondly, when spin-orbit interactions split an array into sub-arrays, the breakdown of j-j coupling may yield large strength transfers between them. Thirdly, in the case of configuration mixing, strength transfers are also observed between whole arrays, and they are sometimes nearly complete. All these changes of the shapes of transition arrays are due to the effects of Slater exchange integrals on the statistical distribution of the line strengths. It is shown how they can be introduced for improving the statistical line-by-line simulation of resolved transition arrays (the RTA model). (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Lab Aimee Cotton, F-91405 Orsay, France. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Bauche, J (reprint author), Lab Aimee Cotton, Batiment 505,Campus Orsay, F-91405 Orsay, France. NR 15 TC 5 Z9 5 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD APR-MAY PY 2000 VL 65 IS 1-3 BP 57 EP 70 DI 10.1016/S0022-4073(99)00055-2 PG 14 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 275TR UT WOS:000084836700007 ER PT J AU Calisti, A Ferri, S Stamm, R Talin, B Lee, RW Klein, L AF Calisti, A Ferri, S Stamm, R Talin, B Lee, RW Klein, L TI Discussion of the validity of binary collision models for electron broadening in plasmas SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID HYDROGEN; SHIFT; LINES AB Recent plasma spectroscopic investigations of line profiles indicate that conditions can be obtained where a usual electron collision operator is unable to describe the entire line profile. This situation arises for plasma conditions when the interactions with electrons is a major broadening mechanism and the quasi-static electron, or non-binary, effects are important. As examples we find that this is the case for high-n hydrogen lines over a wide range of electron densities and low-n hydrogen lines at higher electron density. A solution has been proposed for high-n hydrogen lines by using a frequency-dependent electron broadening operator accounting for some overlapping of the impact and the non-binary regimes. The domain of validity of different approaches that attempt to including many-body dynamical and statistical effects will be discussed and compared with numerical simulations. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Aix Marseille 1, CNRS UMR 6633, Ctr St Jerome, Lab Phys Interact Ion & Mol, F-13397 Marseille 20, France. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Howard Univ, Dept Phys, Washington, DC 20059 USA. RP Calisti, A (reprint author), Univ Aix Marseille 1, CNRS UMR 6633, Ctr St Jerome, Lab Phys Interact Ion & Mol, Case 232, F-13397 Marseille 20, France. OI Calisti, Annette/0000-0001-6727-9286 NR 12 TC 8 Z9 7 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD APR-MAY PY 2000 VL 65 IS 1-3 BP 109 EP 116 DI 10.1016/S0022-4073(99)00060-6 PG 8 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 275TR UT WOS:000084836700012 ER PT J AU Chung, HK Cohen, DH MacFarlane, JJ Bailey, JE Wang, P Moses, GA AF Chung, HK Cohen, DH MacFarlane, JJ Bailey, JE Wang, P Moses, GA TI Statistical fitting analysis of Stark-broadened optically thick ArII spectra measured in ion beam transport experiments SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID IONIZED ARGON LINES; ATOMIC PARAMETERS; PROBABILITIES AB We present a method for fitting a multi-line spectrum with an emission model that accounts for multiple line-broadening mechanisms and the effects of finite optical depth. This technique includes an analysis of the joint-probability distribution of the model parameters that allows one to determine statistically valid confidence limits on the fitted parameters. We apply this method to a time series of optical Ar II spectra produced when an intense lithium beam (kinetic energy of 9 MeV and current density of 22 kA cm(-2)) was injected into an argon gas cell. We show that line optical depth effects are important in these data, and by including finite optical depth as well as Stark and Doppler broadening in the model-fitting procedure, we are able to place meaningful constraints on the time-dependent Ar II level populations and the electron density in the gas cell. The values we derive for these quantities are in reasonably good agreement with detailed collisional-radiative models that include the effects of non-thermal electrons and beam ions. Understanding the time-dependent conditions in the gas cell is critical for efficient beam transport. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Prism Computat Sci, Madison, WI 53703 USA. Univ Delaware, Bartol Res Inst, Newark, DE 19711 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Wisconsin, Fus Technol Inst, Madison, WI 53706 USA. RP Chung, HK (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St,MS-14, Cambridge, MA 02138 USA. NR 11 TC 0 Z9 1 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD APR-MAY PY 2000 VL 65 IS 1-3 BP 135 EP 149 DI 10.1016/S0022-4073(99)00062-X PG 15 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 275TR UT WOS:000084836700014 ER PT J AU Elton, RC Cobble, JA Griem, HR Montgomery, DS Mancini, RC Jacobs, VL Behar, E AF Elton, RC Cobble, JA Griem, HR Montgomery, DS Mancini, RC Jacobs, VL Behar, E TI Anomalous satellite-line intensities from a TRIDENT laser-produced plasma SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID HELIUM-LIKE IONS; DIELECTRONIC SATELLITES; SPECTRA AB An unusual enhancement of two normally-weak and density-stable satellite spectral lines resulting from 2s(2)-1s2p and 1s2s(2)-1s(2)2p transitions in He- and Li-like ions of silicon has been observed in laser-produced plasma experiments at the TRIDENT facility. Space-resolved intensities compared to other more-intense satellites formed by dielectronic recombination are increased by a factor as high as 8 over code predictions at low density (coronal limit). The data were obtained using temporally- and spatially resolved X-ray spectroscopic measurements, supported by Thomson scattering diagnostics. One explanation considered is that the more-intense satellite lines are opacity limited. This suggests a method of determining radiative transfer on the more intense lines, by comparison measurements. Also coincident with these two enhanced features is a K-alpha blend from low stages of ionization, which suggests some alternate interpretation, A complete understanding of the observed anomalies awaits further experimentation. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Maryland, Inst Plasma Res, College Pk, MD 20742 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Nevada, Reno, NV 89557 USA. USN, Res Lab, Washington, DC 20375 USA. Hebrew Univ Jerusalem, IL-91905 Jerusalem, Israel. RP Elton, RC (reprint author), Univ Maryland, Inst Plasma Res, College Pk, MD 20742 USA. OI Montgomery, David/0000-0002-2355-6242 NR 28 TC 21 Z9 21 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD APR-MAY PY 2000 VL 65 IS 1-3 BP 185 EP 193 DI 10.1016/S0022-4073(99)00066-7 PG 9 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 275TR UT WOS:000084836700018 ER PT J AU Fontes, CJ Abdallah, J Clark, REH Kilcrease, DP AF Fontes, CJ Abdallah, J Clark, REH Kilcrease, DP TI Non-LTE modeling of gold plasmas SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID SIMULATIONS AB We continue our work to explore the feasibility of creating detailed atomic models for application to ICF simulations. By further optimizing our atomic data codes we are able to create non-LTE models with a level of complexity approximately one order of magnitude greater (in the number of configurations) than previously obtained. We have calculated emissivities for gold which include on the order of 100,000 configurations per temperature-density point, The inclusion of additional configurations has yielded improved results for quantities such as the emissivity, but the question of spectral convergence is as yet unanswered. Discussion of an effective rate method as a possible way to use these data for in-line, radiation-hydrodynamics modeling is also provided. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Fontes, CJ (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663,MS F663, Los Alamos, NM 87545 USA. OI Kilcrease, David/0000-0002-2319-5934 NR 9 TC 21 Z9 28 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD APR-MAY PY 2000 VL 65 IS 1-3 BP 223 EP 230 DI 10.1016/S0022-4073(99)00069-2 PG 8 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 275TR UT WOS:000084836700021 ER PT J AU Foord, ME Glenzer, SH Thoe, RS Wong, KL Fournier, KB Albritton, JR Wilson, BG Springer, PT AF Foord, ME Glenzer, SH Thoe, RS Wong, KL Fournier, KB Albritton, JR Wilson, BG Springer, PT TI Accurate determination of the charge state distribution in a well characterized highly ionized Au plasma SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID INERTIAL CONFINEMENT FUSION; ABSORPTION-SPECTROSCOPY; COMPLEX SPECTRA; RAY; MODEL AB The density, temperature and charge state distribution are accurately determined in a highly ionized non-LTE Au sample. Laser heated Au microdots buried in a thin Be foil, reach temperatures of 2 keV and ionize into the M-shell. During expansion, the tamped Au samples remain uniform and in near steady-state ionization equilibrium. The electron temperature is measured with time and space resolved Thomson scattering while the density is determined from time-gated X-ray imaging the expanded Au sample. The charge state distribution is obtained from analysis of emission measurements of Au 5f-3d transition arrays in the wavelength range 3.3-3.9 Angstrom, allowing the average charge to be determined to within similar to 1 % accuracy. (C) 2000 Published by Elsevier Science Ltd. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Foord, ME (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-41, Livermore, CA 94551 USA. NR 25 TC 39 Z9 49 U1 1 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD APR-MAY PY 2000 VL 65 IS 1-3 BP 231 EP 241 DI 10.1016/S0022-4073(99)00070-9 PG 11 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 275TR UT WOS:000084836700022 ER PT J AU Glenzer, SH Estabrook, KG Lee, RW MacGowan, BJ Rozmus, W AF Glenzer, SH Estabrook, KG Lee, RW MacGowan, BJ Rozmus, W TI Detailed characterization of laser plasmas for benchmarking of radiation-hydrodynamic modeling SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID INERTIAL-CONFINEMENT-FUSION; ION-ACOUSTIC-WAVES; THOMSON SCATTERING; LIGHT; NOVA; SPECTROMETER; SPECTRUM; DRIVE AB We have applied Thomson scattering for accurate measurements of densities, temperatures, and ionization levels in dense laser-produced gold plasmas, These experiments give a unique data set that has allowed us to make critical comparisons with two-dimensional radiation-hydrodynamic simulations showing that dielectronic recombination is an important process in cooling laser plasmas. Consistent with this result, additional X-ray spectroscopic measurements of the emission from the gold plasma also indicate a rapidly recombining plasma. These findings are important for the development of kinetics models relevant to high-Z laser-irradiated plasmas and to test our calculational capability for future high-density plasma experiments. Published by Elsevier Science Ltd. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Univ Alberta, Dept Phys, Edmonton, AB T6G 2J1, Canada. Univ Calif, Inst Lasers Sci Applicat, Livermore, CA 94550 USA. RP Glenzer, SH (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-399, Livermore, CA 94551 USA. NR 48 TC 12 Z9 13 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD APR-MAY PY 2000 VL 65 IS 1-3 BP 253 EP 271 DI 10.1016/S0022-4073(99)00072-2 PG 19 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 275TR UT WOS:000084836700024 ER PT J AU Haynes, DA Hooper, CF Delamater, ND Pollack, GD Barnes, C Tubbs, DL Jaanimagi, P AF Haynes, DA Hooper, CF Delamater, ND Pollack, GD Barnes, C Tubbs, DL Jaanimagi, P TI Chlorine K-shell spectroscopy of directly driven cylindrical implosions SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID LINE AB K-shell X-ray emission from a chlorinated marker layer is used to diagnose the density and temperature evolution of the inner surface of the ablator in a series of directly driven cylindrical implosions. Because the shape of the emitting region is irregular, the line-of-best-fit (LIBEF) method of Kilkenny et al. [Phys. Rev. A 1980;22:2746.] is applied for the inference of electron density and the results used to find constraints on the temperature of the marker layer. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Florida, Dept Phys, Gainesville, FL 32611 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. Univ Rochester, Laser Energet Lab, Rochester, NY USA. RP Haynes, DA (reprint author), Univ Florida, Dept Phys, Gainesville, FL 32611 USA. NR 8 TC 2 Z9 2 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD APR-MAY PY 2000 VL 65 IS 1-3 BP 297 EP 302 DI 10.1016/S0022-4073(99)00075-8 PG 6 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 275TR UT WOS:000084836700027 ER PT J AU Iglesias, CA Rogers, FJ Shepherd, R Bar-Shalom, A Murillo, MS Kilcrease, DP Calisti, A Lee, RW AF Iglesias, CA Rogers, FJ Shepherd, R Bar-Shalom, A Murillo, MS Kilcrease, DP Calisti, A Lee, RW TI Fast electric microfield distribution calculations in extreme matter conditions SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID STRONGLY COUPLED PLASMAS; DYNAMICS; IONS AB Spectral line shapes provide a powerful tool for characterizing strongly coupled plasmas that have become experimentally more accessible in recent years. Line shape calculations in turn require as input the electric microfield distribution at the emitting atom or ion. The APEX approximation for microfield distributions is computationally fast and suited for weakly as well as strongly coupled plasmas. The currently available APEX program, however, contains computationally difficulties that restrict its range of applicability. Consequently, the code has been improved removing many of its shortcomings. An important new feature is the incorporation of the HNC integral equation solution to the radial distribution functions necessary for the APEX approximation. Published by Elsevier Science Ltd. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NRCN, Beer Sheva, Israel. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Aix Marseille 1, PIIM, Ctr St Jerome, F-13397 Marseille, France. RP Iglesias, CA (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB, Livermore, CA 94550 USA. OI Calisti, Annette/0000-0001-6727-9286; Kilcrease, David/0000-0002-2319-5934 NR 37 TC 26 Z9 26 U1 2 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD APR-MAY PY 2000 VL 65 IS 1-3 BP 303 EP 315 DI 10.1016/S0022-4073(99)00076-X PG 13 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 275TR UT WOS:000084836700028 ER PT J AU Kilcrease, DP Murillo, MS AF Kilcrease, DP Murillo, MS TI The ion electric microfield gradient joint probability distribution function for dense plasmas SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID QUADRUPOLE INTERACTION; NONUNIFORMITY; LINES AB The plasma quasistatic ion electric microfield can be used to describe the effect of the many perturbing ions in a plasma on a single charged particle such as an atomic ion. Microfield spatial derivatives at the charged particle describe the non-uniformity of the electric microfield on the atomic scale and are important for higher-order multipole interactions between the plasma and atomic ions. An example of these multipole effects is the ion-quadrupole effect that leads to the asymmetric broadening of spectral lines. We examine approximations to the constrained electric microfield gradient joint probability distribution function which describes the probability of particular field gradients given a particular value of the plasma microfield. We employ molecular dynamics simulations and analytic approximations based on the APEX microfield description. We find that corrections to a previously published approximation to this joint probability function can be important and that under certain conditions, these probability functions may be approximated by Gaussian distributions. We present a theory for estimating the widths of these Gaussian approximations. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Kilcrease, DP (reprint author), Univ Calif Los Alamos Natl Lab, MS B212,POB 1663, Los Alamos, NM 87545 USA. OI Kilcrease, David/0000-0002-2319-5934 NR 13 TC 9 Z9 9 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD APR-MAY PY 2000 VL 65 IS 1-3 BP 343 EP 352 DI 10.1016/S0022-4073(99)00079-5 PG 10 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 275TR UT WOS:000084836700031 ER PT J AU Langer, SH Scott, HA Marinak, MM Landen, OL AF Langer, SH Scott, HA Marinak, MM Landen, OL TI Towards a complete model of 3D line emission from ICF capsules: results from the first 3D simulations SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID K-SHELL; IMPLOSIONS; SPECTROSCOPY; SPECTRA AB Hydrodynamic instabilities can reduce the yield in inertial confinement fusion (ICF) implosions. Line emission from dopants placed in the capsule can be used to diagnose the extent of the instabilities. In earlier work we compared line emission measured in experiments performed on the Nova laser to one-dimensional mix models and two-dimensional models in which many different instability wavelengths interact. Three-dimensional simulations are required to model properly the saturation of the hydrodynamic instabilities. This paper presents the results of the first three-dimensional simulations of line emission from ICF capsules. The simulations show that the three lines considered here come from different spatial regions. Line ratios cannot be used to determine temperatures without accounting for the spatial dependence of the line emission. Future papers will present detailed comparisons to experiments. Published by Elsevier Science Ltd. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Langer, SH (reprint author), Univ Calif Lawrence Livermore Natl Lab, L-22,POB 808, Livermore, CA 94550 USA. NR 18 TC 7 Z9 7 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD APR-MAY PY 2000 VL 65 IS 1-3 BP 353 EP 366 DI 10.1016/S0022-4073(99)00080-1 PG 14 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 275TR UT WOS:000084836700032 ER PT J AU Faussurier, G More, RM AF Faussurier, G More, RM TI NLTE steady-state response matrix method SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID THERMODYNAMIC-EQUILIBRIUM PLASMAS; STATISTICAL-MECHANICS; IONS; MODEL AB A connection between atomic kinetics and non-equilibrium thermodynamics has been recently established by using a collisional-radiative model modified to include line absorption. The calculated net emission can be expressed as a non-local thermodynamic equilibrium (NLTE) symmetric response matrix. In this paper, this connection is extended to both cases of the average-atom model and the Busquet's model (RAdiative-Dependent IOnization Model, RADIOM). The main properties of the response matrix still remain valid. The RADIOM source function found in the litterature leads to a diagonal response matrix, stressing the absence of any frequency redistribution among the frequency groups at this order of calculation. (C) 2000 Published by Elsevier Science Ltd. All rights reserved. C1 Commissariat Energie Atom, F-91680 Bruyeres Le Chatel, France. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Faussurier, G (reprint author), Commissariat Energie Atom, BP 12, F-91680 Bruyeres Le Chatel, France. NR 20 TC 5 Z9 5 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD APR-MAY PY 2000 VL 65 IS 1-3 BP 387 EP 391 DI 10.1016/S0022-4073(99)00082-5 PG 5 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 275TR UT WOS:000084836700034 ER PT J AU Serduke, FJD Minguez, E Davidson, SJ Iglesias, CA AF Serduke, FJD Minguez, E Davidson, SJ Iglesias, CA TI WorkOp-IV summary: lessons from iron opacities SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article AB The fourth international LTE opacity workshop and code comparison study, WorkOp-IV, was held in Madrid in 1997, Results of this workshop are summarized with a focus on iron opacities. In particular, the astrophysically important photon absorption region between 50 and 80 eV is emphasized for a sequence of iron plasmas at densities and temperatures that produce nearly the same average ionization stage(Z* similar to 8.6). Experimental data that addressed this spectral region is also reviewed. (C) 2000 Published by Elsevier Science Ltd. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Politech Madrid, Inst Nucl Fus, Madrid, Spain. AWE Aldermaston, Aldermaston, England. RP Serduke, FJD (reprint author), Univ Calif Lawrence Livermore Natl Lab, L-183,POB 808, Livermore, CA 94550 USA. NR 7 TC 46 Z9 47 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD APR-MAY PY 2000 VL 65 IS 1-3 BP 527 EP 541 DI 10.1016/S0022-4073(99)00094-1 PG 15 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 275TR UT WOS:000084836700046 ER PT J AU Woolsey, NC Back, CA Lee, RW Calisti, A Mosse, C Stamm, R Talin, B Asfaw, A Klein, LS AF Woolsey, NC Back, CA Lee, RW Calisti, A Mosse, C Stamm, R Talin, B Asfaw, A Klein, LS TI Experimental results on line shifts from dense plasmas SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID POLARIZATION SHIFT; BOUND LEVELS; IONS AB The dynamics of the implosion of a deuterium-filled microsphere has been investigated via the detailed analysis of the Ar 1s(2)-1s3p(1)P line shape. Ar is doped into the deuterium core for diagnostic purposes. For the analysis calculations of Ar 1-3 line shape including lithium-like dielectronic satellites were compared with time-resolved data. Three fitting parameters were used: (a) electron temperature, (b) electron density, and (c) relative shift of the wavelength axis between calculation and data, The temporal evolution of the core electron temperature and density were derived, and the shot-to-shot formation of the core plasma was shown to be reliable and reproducible. We report on the wavelength shift of the Ar 1s(2)-1s3p(1)P line shape between electron densities of 10(23)-10(24) cm(-3), results indicate a systematic red shift with increasing density. (C) 2000 Elsevier Science Ltd, All rights reserved. C1 Univ York, Dept Phys, York YO10 5DD, N Yorkshire, England. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Univ Aix Marseille 1, F-13397 Marseille, France. Howard Univ, Dept Phys, Washington, DC 20059 USA. RP Woolsey, NC (reprint author), Rutherford Appleton Lab, Cent Laser Facil, Didcot OX11 0QX, Oxon, England. OI Calisti, Annette/0000-0001-6727-9286 NR 12 TC 16 Z9 16 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD APR-MAY PY 2000 VL 65 IS 1-3 BP 573 EP 578 DI 10.1016/S0022-4073(99)00096-5 PG 6 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 275TR UT WOS:000084836700048 ER PT J AU Zeng, XC Zhang, LF Li, YS AF Zeng, XC Zhang, LF Li, YS TI Effects of non-equilibrium radiative transfer and opacity on the implosion of capsule filled DT gas SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID INERTIAL CONFINEMENT FUSION; DRIVEN AB Implosion behavior of plastic capsules filled with DT gas has been investigated numerically using two different approximations for the radiative transfer equation coupled with energy equations of electron and ion. The effects of the non-equilibrium radiative transfer and opacity on the implosion of capsule are given. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Inst Appl Phys & Computat Math, Lab Computat Phys, Beijing 100088, Peoples R China. RP Zeng, XC (reprint author), Care of Lee R, LLNL, L-399,POB 808, Livermore, CA 94550 USA. NR 8 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 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD APR-MAY PY 2000 VL 65 IS 1-3 BP 579 EP 594 DI 10.1016/S0022-4073(99)00097-7 PG 16 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 275TR UT WOS:000084836700049 ER PT J AU Howell, SL Sigg, RA Moore, FS DeVol, TA AF Howell, SL Sigg, RA Moore, FS DeVol, TA TI Calibration and validation of a Monte Carlo model for PGNAA of chlorine in soil SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 10th International Conference on Modern Trends in Activation Analysis (MTAA-10) CY APR 19-23, 1999 CL NIH, BETHESDA, MARYLAND SP Natl Inst Stand & Technol HO NIH ID GAMMA-RAYS; ENVIRONMENTAL-SAMPLES; ACTIVATION-ANALYSIS; MCNP-CODE; CAPTURE; COLD AB A prompt gamma-ray neutron activation analysis (PGNAA) system was used to calibrate and validate a Monte Carlo model as a proof of principle for the quantification of chlorine in soil. First, the response of an n-type HPGe detector to point sources of Co-60 and Eu-152 was determined experimentally and used to calibrate an MCNP4a model of the detector. The refined MCNP4a detector model can predict the absolute peak detection efficiency within 12% in the energy range of 120-1400 keV. Second, a PGNAA system consisting of a light-water moderated Cf-252 (1.06 mu g) neutron source, and the shielded and collimated HPGe detector was used to collect prompt gamma-ray spectra from Savannah River Site (SRS) soil spiked with chlorine. The spectra were used to calculate the minimum detectable concentration (MDC) of chlorine and the prompt gamma-ray detection probability. Using the 252Cf based PGNAA system, the MDC for Cl in the SRS soil is 4400 mu g/g for an 1800-second irradiation based on the analysis of the 6110 keV prompt gamma-ray. MCNP4a was used to predict the PGNAA detection probability, which was accomplished by modeling the neutron and gamma-ray transport components separately. In the energy range of 788 to 6110 keV, the MCNP4a predictions of the prompt gamma-ray detection probability were generally within 60% of the experimental value, thus validating the Monte Carlo model. C1 Clemson Univ, Clemson, SC 29634 USA. Westinghouse Savannah River Co, Savannah River Technol Ctr, Aiken, SC 29808 USA. RP Howell, SL (reprint author), Clemson Univ, Clemson, SC 29634 USA. NR 18 TC 5 Z9 5 U1 0 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD APR PY 2000 VL 244 IS 1 BP 173 EP 178 DI 10.1023/A:1006740921047 PG 6 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 338GH UT WOS:000088410400029 ER PT J AU Mozharivskyj, Y Kuz'ma, YB AF Mozharivskyj, Y Kuz'ma, YB TI Ternary phosphide Ho2Cu6-xP5-y, its crystal structure, and REm+n(Cu2P3)(m)(Cu4P2)(n) relationship with other rhombohedral rare-earth copper phosphides SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article DE holmium copper phosphide; crystal structure; structural relationships AB Crystals of the phosphide Ho2Cu6-xP5-y (x = 0.41, y = 0.50) have been prepared by annealing pressed powders of the elements at 800 degrees C for 2 weeks. The structure was determined by single-crystal methods: space group R(3) over bar m (No. 166), Z = 3, a = 3.976(1) Angstrom, c = 40.554(8) Angstrom, R = 0.045 for 243 independent reflections [F> 4 sigma(F)]. The unit cell of Ho2Cu6-xP5-y can be built from a close packing of Ho atoms and fragments of Cu3P, with one of the fragments containing additional P atoms, It can be also considered as an intercalation of additional P atoms in the YbCu3-xP2 structure (P. Klufers, A. Mewis, and H. U. Schuster, Z. Kristallogr. 149, 211 (1979)). The REm+n(Cu2P3)(m)(Cu4P2)(n) relationship with other rare-earth copper phosphides, having similar structural characteristics is discussed. (C) 2000 Academic Press. C1 Iowa State Univ Sci & Technol, Dept Chem, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Lviv State Univ, Inst Analyt Chem, UA-290005 Lviv, Ukraine. RP Mozharivskyj, Y (reprint author), Iowa State Univ Sci & Technol, Dept Chem, Ames, IA 50011 USA. NR 16 TC 3 Z9 3 U1 1 U2 4 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 APR PY 2000 VL 151 IS 1 BP 150 EP 156 DI 10.1006/jssc.2000.8639 PG 7 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA 302BF UT WOS:000086344500023 ER PT J AU Butler, WH Zhang, XG MacLaren, JM AF Butler, WH Zhang, XG MacLaren, JM TI Semiclassical theory of spin-dependent transport magnetic multilayers SO JOURNAL OF SUPERCONDUCTIVITY LA English DT Article DE Boltzmann equation; spin-dependent; magnetic multilayers ID ANTIFERROMAGNETIC INTERLAYER EXCHANGE; GIANT MAGNETORESISTANCE; NEGATIVE MAGNETORESISTANCE; METALLIC MULTILAYERS; LAYERED STRUCTURES; AG/CO MULTILAYERS; JUNCTIONS; FILMS AB The semiclassical Boltzmann equation is applied to spin-dependent transport in magnetic multilayers. The origin of the giant magnetoresistance effect is explained for both the case in which the current hows parallel to the layers and the case in which it is perpendicular to the layers. The approach is first-principles based and includes effects of vertex corrections and local fields. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Tulane Univ, New Orleans, LA 70018 USA. RP Butler, WH (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 42 TC 18 Z9 18 U1 1 U2 2 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0896-1107 J9 J SUPERCOND JI J. Supercond. PD APR PY 2000 VL 13 IS 2 BP 221 EP 238 DI 10.1023/A:1007799916385 PG 18 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 294NF UT WOS:000085916800005 ER PT J AU Gor'kov, L Kresin, V AF Gor'kov, L Kresin, V TI Metal-insulator transition in percolation doped systems as a phenomenon SO JOURNAL OF SUPERCONDUCTIVITY LA English DT Article DE metal-insulator transition; doped materials; manganites ID PULSED-NEUTRON DIFFRACTION; COLOSSAL MAGNETORESISTANCE; LA1-XSRXMNO3; LA1-XCAXMNO3; MANGANITES AB The percolative picture for the metal-insulator transition in doped materials is discussed. We focus on Various properties of manganites. The approach has now a strong experimental support. The percolative phenomenon implies the presence of intrinsic inhomogeneity, but, nevertheless, the picture is different from that of the electronic phase separation. C1 Florida State Univ, Natl High Magnet Field Lab, Tallahassee, FL 32310 USA. Russian Acad Sci, LD Landau Theoret Phys Inst, Moscow 11334, Russia. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Gor'kov, L (reprint author), Florida State Univ, Natl High Magnet Field Lab, Tallahassee, FL 32310 USA. NR 43 TC 15 Z9 15 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0896-1107 J9 J SUPERCOND JI J. Supercond. PD APR PY 2000 VL 13 IS 2 BP 239 EP 245 DI 10.1023/A:1007752000455 PG 7 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 294NF UT WOS:000085916800006 ER PT J AU Swift, GW Spoor, PS AF Swift, GW Spoor, PS TI Thermal diffusion and mixture separation in the acoustic boundary layer (vol 106, pg 1794, 1999) SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Correction C1 Univ Calif Los Alamos Natl Lab, Condensed Matter & Thermal Phys Grp, Los Alamos, NM 87545 USA. RP Swift, GW (reprint author), Univ Calif Los Alamos Natl Lab, Condensed Matter & Thermal Phys Grp, POB 1663, Los Alamos, NM 87545 USA. NR 1 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD APR PY 2000 VL 107 IS 4 BP 2299 EP 2299 DI 10.1121/1.428558 PG 1 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA 302LR UT WOS:000086367000054 ER PT J AU Otis, LL Everett, MJ Sathyam, US Colston, BW AF Otis, LL Everett, MJ Sathyam, US Colston, BW TI Optical coherence tomography: A new imaging technology for dentistry SO JOURNAL OF THE AMERICAN DENTAL ASSOCIATION LA English DT Article ID TISSUE; BIOPSY AB Background. Optical coherence tomography, or OCT, is a new diagnostic imaging technique that has many potential dental applications. The authors present the first intraoral dental images made using this technology. Methods. The authors constructed a prototype dental OCT system. This system creates cross-sectional images by quantifying the reflections of infrared light from dental structures interferometrically. Results. We used our prototype system to make dental OTC images of healthy adults in a clinical setting. These OCT images depicted both hard and soft oral tissues at high resolution. Conclusions. OCT images exhibit microstructural detail that cannot be obtained with current imaging modalities. Using this new technology, visual recordings of periodontal tissue contour, sucular depth and connective tissue attachment now are possible. The internal aspects and marginal adaptation of porcelain and composite restorations can be visualized. Clinical Implications. There are several advantages of OCT compared with conventional dental imaging. This new imaging technology is safe, versatile, inexpensive and readily adapted to a clinical dental environment. C1 Univ Connecticut, Dept Oral Diag, Sch Dent Med, Farmington, CT 06030 USA. Univ Calif Lawrence Livermore Natl Lab, Med Technol Program, Livermore, CA USA. RP Otis, LL (reprint author), Univ Connecticut, Dept Oral Diag, Sch Dent Med, 263 Farmington Ave,MC-1605, Farmington, CT 06030 USA. NR 14 TC 93 Z9 98 U1 2 U2 19 PU AMER DENTAL ASSN PI CHICAGO PA 211 E CHICAGO AVE, CHICAGO, IL 60611 USA SN 0002-8177 J9 J AM DENT ASSOC JI J. Am. Dent. Assoc. PD APR PY 2000 VL 131 IS 4 BP 511 EP + PG 4 WC Dentistry, Oral Surgery & Medicine SC Dentistry, Oral Surgery & Medicine GA 302LN UT WOS:000086366700021 PM 10770016 ER PT J AU Wunschel, DS Tolic, LP Feng, BB Smith, RD AF Wunschel, DS Tolic, LP Feng, BB Smith, RD TI Electrospray ionization Fourier transform ion cyclotron resonance analysis of large polymerase chain reaction products SO JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY LA English DT Article ID FTICR MASS-SPECTROMETRY; NUCLEIC-ACIDS; PCR PRODUCTS; HUMAN DNA; DIAGNOSIS; UTILITY; SAMPLES AB In previous work, we demonstrated the use of electrospray ionization to analyze small differences in size or sequence of relatively small polymerase chain reaction (PCR) products of 114 base pairs or less. The sequence information required to answer a biological question may be only a single nucleotide substitution or deletion. In many cases, the regions where these sequence variations can occur are several hundred base pairs in length, and the analysis of large PCR products is therefore desirable. Therefore, we have attempted to expand the size range of PCR products that can be analyzed by electrospray ionization (ESI) Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. Previous work has shown that the difficulties associated with PCR product analysis increase with product size. A revised cleanup scheme was employed to target the removal of detergents with ethanol wash or precipitation steps, followed by additional desalting. Additionally, an in-trap cleanup to collisionally induce dissociation of noncovalent salt adducts was employed. This approach was extended to a 223 base pair PCR product yielding mass measurement accuracy within 26 ppM. The mass measurement accuracy obtained illustrates that a single base substitution could be identified at this size of PCR product with a 7 tesla ESI-FTICR. (J Am Soc Mass Spectrom 2000, 11, 33-337) (C) 2000 American Society for Mass Spectrometry. C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Smith, RD (reprint author), Pacific NW Lab, Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. RI Wunschel, David/F-3820-2010; Smith, Richard/J-3664-2012 OI Smith, Richard/0000-0002-2381-2349 NR 26 TC 19 Z9 19 U1 0 U2 2 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 1044-0305 J9 J AM SOC MASS SPECTR JI J. Am. Soc. Mass Spectrom. PD APR PY 2000 VL 11 IS 4 BP 333 EP 337 DI 10.1016/S1044-0305(99)00156-7 PG 5 WC Chemistry, Analytical; Chemistry, Physical; Spectroscopy SC Chemistry; Spectroscopy GA 298RA UT WOS:000086151900007 PM 10757169 ER PT J AU Alfriend, KT Schaub, H AF Alfriend, KT Schaub, H TI Dynamic and central of spacecraft formations: Challenges and some solutions SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article; Proceedings Paper CT Richard H Battin Astrodynamics Symposium CY MAR 19-21, 2000 CL TEXAX A&M UNIV, COLLEGE STN, TEXAS SP Amer Astronaut Soc, Texas Eng Exptl Stn, Aerosp Engn Dept HO TEXAX A&M UNIV AB Presented is an analytic method to establish J(2) invariant relative orbits, that is, relative orbit motions that do not drift apart. Working with mean orbit elements, the secular relative drift of the longitude of the ascending node and the argument of latitude between two neighboring orbits are set equal. Two first order conditions constrain the differences between the chief and deputy momenta elements (semi-major axis, eccentricity and inclination angle), while the other three angular differences (ascending node, argument of perigee and mean anomaly), can be chosen at will. Several challenges in designing such relative orbits are discussed. For near polar orbits or near circular orbits, enforcing the equal nodal rate condition may result in impractically large relative orbits if a difference in inclination angle is prescribed. In the latter case, compensating for a difference in inclination angle becomes exceedingly difficult as the eccentricity approaches zero. The third issue discussed is the relative argument of perigee and mean anomaly drift. While this drift has: little or no effect on the relative orbit geometry for small or near-zero eccentricities, for larger eccentricities it causes the relative orbit to enlarge and contract over time. A simple control solution to this issue is presented. Further, convenient expressions are presented which allow for quick annual fuel budget estimations. For given initial orbit element differences, these formulas estimate what Deltav is required to compensate for the J(2) induced relative drift. C1 Texas A&M Univ, Dept Aerosp Engn, College Stn, TX 77843 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Alfriend, KT (reprint author), Texas A&M Univ, Dept Aerosp Engn, College Stn, TX 77843 USA. NR 9 TC 41 Z9 47 U1 1 U2 6 PU AMER ASTRONAUTICAL SOC PI SPRINGFIELD PA 6352 ROLLING MILL PLACE SUITE 102, SPRINGFIELD, VA 22152 USA SN 0021-9142 J9 J ASTRONAUT SCI JI J. Astronaut. Sci. PD APR-SEP PY 2000 VL 48 IS 2-3 BP 249 EP 267 PG 19 WC Engineering, Aerospace SC Engineering GA 435WW UT WOS:000168906000009 ER PT J AU Almgren, AS AF Almgren, AS TI A new look at the pseudo-incompressible solution to Lamb's problem of hydrostatic adjustment SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID ANELASTIC APPROXIMATION AB The pseudo-incompressible solution to Lamb's problem of the hydrostatic adjustment of the atmosphere is revisited using a generalized formulation that allows time variation of the base state. It is found that the generalized pseudo-incompressible equations do reproduce the compressible solution of the nonlinear hydrostatic adjustment in the limit of small heating. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Almgren, AS (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, MS 50A-1148,1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 7 TC 12 Z9 12 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 APR 1 PY 2000 VL 57 IS 7 BP 995 EP 998 DI 10.1175/1520-0469(2000)057<0995:ANLATP>2.0.CO;2 PG 4 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 300FP UT WOS:000086242700007 ER PT J AU Verhoff, M Alkire, R AF Verhoff, M Alkire, R TI Experimental and modeling studies of single pits on pure aluminum in pH 11 NaCl solutions I. Laser initiated single pits SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID CORROSION PITS; CORRODING PIT; PITTING CORROSION; CHEMICAL NATURE; 0.5M NACL; GROWTH; TRANSPORT; DISSOLUTION; DIFFUSION; MIGRATION AB The anodic dissolution of pure aluminum in pH 11 chloride media was investigated. Individual hemispherical corrosion pits were produced by a laser initiation technique, and electrochemical measurements were analyzed to determine the effect of diffusion and migration on single pit growth. Several mathematical models, which included both migration and diffusion as transport modes, were developed to interpret experimental results and to predict concentration profiles that resulted from dissolution based on the assumption of a hemispherical corrosion pit geometry. Model equations were solved by a quasi-potential transformation technique. The results for a model that considered a simple case of three ionic species demonstrated that it was essential to include both migration and diffusion phenomena in the model, contrary to previous experimental studies that concluded that pit dissolution was controlled by diffusion only. The results of a more advanced model that included two hydrolysis reactions for aluminum predicted a pH (<3.5 in 90% of the computational domain) that was in good agreement with experimental data (pH 3-4). The addition of the hydrolysis reactions had no effect on the concentration profiles of the three species considered in the simple chemistry model. Models that included homogeneous reactions to lest the hypothesis of formation of an aluminum oxychloride salt [Al(OH)(2)Cl] predicted a pH greater than or equal to 5, and also that the concentration of the salt was significantly smaller than the estimated saturation concentration of 3 mol/L. (C) 2000 The Electrochemical Society. S0013-4651(98)11-009-1. All rights reserved. C1 Univ Illinois, Dept Chem Engn, Urbana, IL 61801 USA. Univ Illinois, Frederick Seitz Mat Res Lab, Urbana, IL 61801 USA. RP Verhoff, M (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 29 TC 20 Z9 20 U1 0 U2 4 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 APR PY 2000 VL 147 IS 4 BP 1349 EP 1358 DI 10.1149/1.1393361 PG 10 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 302AY UT WOS:000086343800020 ER PT J AU Verhoff, M Alkire, R AF Verhoff, M Alkire, R TI Experimental and modeling studies of single corrosion pits on pure aluminum in pH 11 NaCl solutions II. Pit stability SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID GROWTH; PASSIVATION; METALS; FILMS AB The critical solution composition required for sustained growth of hemispherical single corrosion pits on pure aluminum in basic sodium chloride solution was studied. Single corrosion pits were initiated by using a laser initiation technique. Electrochemical current interruption experiments were used to probe the effects of bulk solution concentration and potential on pit stability. A mathematical model was used to analyze the results from one type of current interruption experiment that investigated the effect of pit size on pit stability. The mathematical model extended the results of previous work (Part I, the previous article, which considered the profiles that develop during pit growth, to include transient behavior Juring the relaxation of the concentration profiles. The solution of the transient model was performed by first transforming the equations using the conformal mapping technique of Verbrugge rr ill. [Electrochim. Acta. 38, 1649 (1993)]. Numerical results were compared with experimental data and were interpreted on the basis of the hypothesis that a critical concentration of an ionic species is required in the pit for stability. (C) 2000 The Electrochemical Society. S0013-4651(98)11-010-8. All rights reserved. C1 Univ Illinois, Dept Chem Engn, Urbana, IL 61801 USA. Univ Illinois, Frederick Seitz Mat Res Lab, Urbana, IL 61801 USA. RP Verhoff, M (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 24 TC 5 Z9 5 U1 1 U2 3 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 APR PY 2000 VL 147 IS 4 BP 1359 EP 1365 DI 10.1149/1.1393362 PG 7 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 302AY UT WOS:000086343800021 ER PT J AU Mukundan, R Brosha, EL Brown, DR Garzon, FH AF Mukundan, R Brosha, EL Brown, DR Garzon, FH TI A mixed-potential sensor based on a Ce0.8Gd0.2O1.9 electrolyte and platinum and gold electrodes SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article; Proceedings Paper CT 195th Meeting of the Electrochemical-Society CY MAY 02-06, 1999 CL SEATTLE, WASHINGTON SP Electrochem Soc, Energy Technol Div, US DOE Off Basic Energy Sci, US DOE Off Energy Efficieny & Renewable Energy, Natl Renewable Energy Lab ID ZIRCONIA OXYGEN SENSOR; STABILIZED ZIRCONIA; HYDROGEN SENSOR; OXIDE ELECTRODE AB A Pt/Ce0.8Gd0.2O1.9/Au mixed-potential sensor was constructed and its response to reducing gases in an oxygen containing stream was measured at T = 550 and 600 degrees C. The sensor response was maximum for H-2 and negligible for methane; other gases followed the trend methane < propane < CO, propylene < hydrogen. The mixed potentials developed at the Au and Pt electrodes were also independently monitored with respect to Pt air-reference electrodes. The mixed potential at the Au electrode was always higher (more negative) than that at the Pt electrode irrespective of the type of reducing gas used. The polarization curves of the two electrodes during oxygen reduction were also measured. These measurements revealed that the mixed potential at the electrodes was dependent on both the amount of electrochemical oxidation of reducing gas and the overpotential for oxygen reduction. While the response of the Pt electrode was found to be stable at both 600 and 550 degrees C, the Au electrode had stability problems at 600 degrees C due to the changing morphology of the gold him. (C) 2000 The Electrochemical Society. S0013-3651 (99)06-033-4. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Elect & Electrochem Mat & Devices Grp, Los Alamos, NM 87545 USA. RP Mukundan, R (reprint author), Univ Calif Los Alamos Natl Lab, Elect & Electrochem Mat & Devices Grp, POB 1663, Los Alamos, NM 87545 USA. NR 11 TC 57 Z9 58 U1 1 U2 6 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 APR PY 2000 VL 147 IS 4 BP 1583 EP 1588 DI 10.1149/1.1393398 PG 6 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 302AY UT WOS:000086343800057 ER PT J AU Lee, CH Yamada, K Endoh, Y Shirane, G Birgeneau, RJ Kastner, MA Greven, M Kim, YJ AF Lee, CH Yamada, K Endoh, Y Shirane, G Birgeneau, RJ Kastner, MA Greven, M Kim, YJ TI Energy spectrum of spin fluctuations in superconducting La2-xSrxCuO4 (0.10 <= x <= 0.25) SO JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN LA English DT Article DE La2-xSrxCuO4; high-T-c superconductor; spin fluctuation; neutron scattering ID FLOATING-ZONE FURNACE; MAGNETIC FLUCTUATIONS; NEUTRON-SCATTERING; TRANSITION TEMPERATURE; LA1.85SR0.15CUO4; DEPENDENCE; STATE; SUSCEPTIBILITY; EXCITATION; TRANSPORT AB The energy spectrum of incommensurate spin fluctuations in superconducting Sr-doped La2CuO4 has been studied by inelastic neutron scattering experiments. An energy gap in the spin excitation spectrum is observed in the superconducting state of optimally doped (a: = 0.15) and slightly overdoped (a: = 0.18) samples. At temperatures well below T-c, the incommensurate peaks diminish rapidly in intensity with decreasing energy below similar to 8 meV and merge into the background below similar to 3.5 meV for x = 0.15 and similar to 4.5 meV for a: = 0.18. For both samples, the energy spectrum of the q-integrated spin susceptibility, chi "(omega), exhibits an enhancement around 7 meV, which is caused by a broadening in the momentum width of the incommensurate peaks. The gap-like structure in the energy spectrum and the enhancement of chi "(omega) survive at T-c. On the other hand, for both underdoped (a: = 0.10) and heavily overdoped (a: = 0.25) samples there is neither a clear energy gap nor an enhancement of chi "(omega) below T-c. C1 Tohoku Univ, Dept Phys, Sendai, Miyagi 9808578, Japan. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. MIT, Ctr Mat Sci & Engn, Cambridge, MA 02139 USA. Electrotech Lab, Tsukuba, Ibaraki 3058568, Japan. Kyoto Univ, Inst Chem Res, Uji, Kyoto 6110011, Japan. Stanford Univ, Dept Appl Phys, Stanford, CA 94305 USA. RP Lee, CH (reprint author), Tohoku Univ, Dept Phys, Sendai, Miyagi 9808578, Japan. RI Yamada, Kazuyoshi/C-2728-2009; Kim, Young-June /G-7196-2011 OI Kim, Young-June /0000-0002-1172-8895 NR 30 TC 51 Z9 51 U1 0 U2 3 PU PHYSICAL SOC JAPAN PI TOKYO PA YUSHIMA URBAN BUILDING 5F, 2-31-22 YUSHIMA, BUNKYO-KU, TOKYO, 113-0034, JAPAN SN 0031-9015 J9 J PHYS SOC JPN JI J. Phys. Soc. Jpn. PD APR PY 2000 VL 69 IS 4 BP 1170 EP 1176 DI 10.1143/JPSJ.69.1170 PG 7 WC Physics, Multidisciplinary SC Physics GA 309RW UT WOS:000086783900030 ER PT J AU Goff, F McMurtry, GM AF Goff, F McMurtry, GM TI Tritium and stable isotopes of magmatic waters SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Review DE magmatic fluids; tritium; stable isotopes; volcanic gases; chemistry ID MOUNT-ST-HELENS; HYDROGEN-ISOTOPE; KILAUEA-VOLCANO; VULCANO-ISLAND; VALLES CALDERA; NEW-MEXICO; GALAPAGOS-ARCHIPELAGO; HYDROTHERMAL SYSTEM; GEOTHERMAL SYSTEM; GALERAS-VOLCANO AB To investigate the isotopic composition and age of water in volcanic gases and magmas, we analyzed samples from 11 active volcanoes ranging in composition from tholeiitic basalt to rhyolite: Mount St. Helens (USA), Kilauea (USA), Pacaya (Guatemala), Galeras (Colombia), Satsuma Iwo-Jima (Japan), Sierra Negra and Alcedo (Ecuador), Vulcano (Italy), Paricutin (Mexico), Kudryavy (Russia), and White island (New Zealand). Tritium at relatively low levels (0.1-5 T.U.) is found in most emissions from high-temperature volcanic fumaroles sampled, even at discharge temperatures >700 degrees C. Although magmatic fluids sampled from these emissions usually contain high CO2, S-total, HCl, HF, B, Br, He-3 R/R-A, and low contents of air components, stable isotope and tritium relations of nearly all such fluids show mixing of magmatic volatiles with relatively young meteoric water (model ages less than or equal to 75 y). Linear delta D/delta(18)O and H-3/delta(18)O mixing trends of these two end-members are invariably detected at are volcanoes. Tritium is also detected in fumarole condensates at hot spot basalt volcanoes, but collecting samples approaching the composition of end-member magmatic fluid is exceedingly difficult, in situ production of H-3, mostly from spontaneous fission of U-238 in magmas is calculated to be <0.001 T.U., except for the most evolved compositions (xhigh U, Th, and Li and low H2O contents). These Values are below the detection limit of H-3 by conventional analytical techniques (about 0.01 T.U. at best). We found no conclusive evidence that natural fusion in the Earth produces anomalous amounts of detectable H-3 (>0.05 T.U.). (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Geol Geochem Grp, Los Alamos, NM 87545 USA. Univ Hawaii, SOEST, Dept Oceanog, Honolulu, HI 96822 USA. RP Goff, F (reprint author), Univ Calif Los Alamos Natl Lab, Geol Geochem Grp, MS D462, Los Alamos, NM 87545 USA. NR 103 TC 65 Z9 65 U1 2 U2 17 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0273 J9 J VOLCANOL GEOTH RES JI J. Volcanol. Geotherm. Res. PD APR PY 2000 VL 97 IS 1-4 BP 347 EP 396 DI 10.1016/S0377-0273(99)00177-8 PG 50 WC Geosciences, Multidisciplinary SC Geology GA 328AW UT WOS:000087827500020 ER PT J AU Cooper, LW Kelley, JM Bond, LA Orlandini, KA Grebmeier, JM AF Cooper, LW Kelley, JM Bond, LA Orlandini, KA Grebmeier, JM TI Sources of the transuranic elements plutonium and neptunium in arctic marine sediments SO MARINE CHEMISTRY LA English DT Article DE plutonium; neptunium; Arctic Ocean; radioactivity ID FALLOUT PLUTONIUM; REPROCESSING WASTES; MASS-SPECTROMETRY; SOUTHERN URALS; ATOM RATIOS; KARA SEA; TRANSPORT; OCEAN; CONTAMINANTS; ICE AB We report here thermal ionization mass spectrometry measurements of Pu-239, Pu-240, Pu-241, Pu-242, and Np-237 isolated from oceanic, estuarine, and riverine sediments from the Arctic Ocean Basin. Pu-238/Pu239+240 activity ratios are also reported for alpha spectrometric analyses undertaken on a subset of these samples. Our results indicate that the Pu in sediments on the Alaskan shelf and slope, as well as that in the deep basins (Amerasian and Eurasian) of the Arctic Ocean, has its origin in stratospheric and tropospheric fallout. Sediments from the Ob and Yenisei Rivers show isotopic Pu signatures that are distinctly different from those of northern-hemisphere stratospheric fallout and indicate the presence of weapons-grade Pu originating from nuclear fuel reprocessing wastes generated at Russian facilities within these river catchments. Consequently, sediments of the Eurasian Arctic Ocean, particularly those in the Barents and Kara Seas, probably contain a mixture of Pu from stratospheric fallout, tropospheric fallout, and fuel-reprocessing wastes of riverine origin. In particular, the Pu-241/Pu-239 ratios observed in these sediments are inconsistent with significant contributions of Pu to the arctic sediments studied from western European reprocessing facilities, principally Sellafield in the UK. Several other potential sources of Pu to arctic sediments can also be excluded as significant based upon the transuranic isotope ratios presented. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Tennessee, Dept Ecol & Evolutionary Biol, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Pacific NW Lab, Richland, WA 99352 USA. Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. RP Cooper, LW (reprint author), Univ Tennessee, Dept Ecol & Evolutionary Biol, Knoxville, TN 37996 USA. RI Cooper, Lee/E-5251-2012; Grebmeier, Jacqueline/L-9805-2013 OI Cooper, Lee/0000-0001-7734-8388; Grebmeier, Jacqueline/0000-0001-7624-3568 NR 52 TC 55 Z9 58 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-4203 J9 MAR CHEM JI Mar. Chem. PD APR PY 2000 VL 69 IS 3-4 BP 253 EP 276 DI 10.1016/S0304-4203(99)00109-7 PG 24 WC Chemistry, Multidisciplinary; Oceanography SC Chemistry; Oceanography GA 307AV UT WOS:000086632000006 ER PT J AU Sugama, T AF Sugama, T TI Antioxidants for retarding hydrothermal oxidation of polyphenylenesulfide coatings in geothermal environments SO MATERIALS LETTERS LA English DT Article DE polyphenylenesulfide; tetrakis [methylene (3,5,-di-t-butyl-4-hydroxyhydrocinnamate)] methane; antioxidant ID PHENOLIC ANTIOXIDANTS AB Tetrakis [methylene (3,5,-di-t-butyl-4-hydroxyhydrocinnamate)] methane (TMBHM) antioxidant was used to markedly retard the rate of hydrothermal oxidation of polyphenylenesulfide (PPS) thermoplastic proposed as anti-corrosion and -fouling coatings to carbon steel substrates in geothermal environments at temperatures up to 200 degrees C. A phenolic hydrogen donor within TMBHM acted to trap the free sulfur and aryl radicals generated by hydrothermal degradation of PPS during a period of the oxidative induction, thereby terminating the propagation of oxidation in the PPS. Thus, TMBHM-modified PPS coatings after exposure to a low pH(similar to 1.6) brine at 200 degrees C still maintained properties that met the following two criteria for the corrosion-preventing barriers: one was a lower susceptibility to moisture due to low surface energy; and the other was related to the high pore resistance, R-p, of > 10(6) Ohm cm(2). (C) 2000 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Dept Appl Sci, Div Mat & Chem Sci, Upton, NY 11973 USA. RP Sugama, T (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Div Mat & Chem Sci, Upton, NY 11973 USA. NR 11 TC 7 Z9 7 U1 0 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-577X J9 MATER LETT JI Mater. Lett. PD APR PY 2000 VL 43 IS 4 BP 185 EP 191 DI 10.1016/S0167-577X(99)00257-8 PG 7 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 305JE UT WOS:000086535700006 ER PT J AU Miles, PC Barlow, RS AF Miles, PC Barlow, RS TI A fast mechanical shutter for spectroscopic applications SO MEASUREMENT SCIENCE AND TECHNOLOGY LA English DT Article DE combustion diagnostics; spectrometer and spectroscopic instrumentation; flames; shutter; chopper AB The design and implementation of a fast mechanical shutter for the entrance slit of a spectrograph is presented. The shutter allows the high quantum efficiency, dynamic range and spatial resolution of back-illuminated CCD detectors to be exploited for laser-spectroscopic measurements in environments where continuous background interference exists. It permits a 9.1 mu s exposure for a 0.8 mm slit width and has 100% transmission and virtually infinite attenuation in the closed state. Additionally, timing signals are generated in order to permit synchronous laser operation. Testing of the shutter demonstrates that good suppression of background radiation is obtained in Raman line-imaging experiments performed in luminous, partially premixed flames. Shot-noise-limited single-laser-pulse Raman scattering measurements in air are also demonstrated. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94550 USA. RP Sandia Natl Labs, Combust Res Facil, Livermore, CA 94550 USA. NR 14 TC 9 Z9 9 U1 0 U2 5 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0957-0233 EI 1361-6501 J9 MEAS SCI TECHNOL JI Meas. Sci. Technol. PD APR PY 2000 VL 11 IS 4 BP 392 EP 397 DI 10.1088/0957-0233/11/4/308 PG 6 WC Engineering, Multidisciplinary; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 309XD UT WOS:000086793800008 ER PT J AU Walter, PL AF Walter, PL TI Dynamic force pressure and acceleration - Part 6 - Filtering in the measurement system SO MEASUREMENTS & CONTROL LA English DT Article AB Filters are used to attenuate unwanted parts of signals in the frequency domain. They are often used with signals from force and pressure transducers and accelerometers in an attempt to remove high frequency distortion. However, if not properly selected, the filters can introduce additional distortion. This part focuses on proper filter selection and application in the measurement system. C1 Sandia Natl Labs, Livermore, CA 94550 USA. Texas Christian Univ, Dept Engn, Ft Worth, TX 76129 USA. RP Walter, PL (reprint author), Sandia Natl Labs, Livermore, CA 94550 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU MEASUREMENTS & DATA CORP PI PITTSBURGH PA 2994 W LIBERTY AVE, PITTSBURGH, PA 15216 USA SN 0148-0057 J9 MEAS CONTROL-US JI Meas. Control PD APR PY 2000 IS 199 BP 62 EP 65 PG 4 WC Automation & Control Systems; Instruments & Instrumentation SC Automation & Control Systems; Instruments & Instrumentation GA 312KX UT WOS:000086943400002 ER PT J AU Breeden, WK Hamby, DM Carey, JE Eckerman, KF McPherson, DW Knapp, FF AF Breeden, WK Hamby, DM Carey, JE Eckerman, KF McPherson, DW Knapp, FF TI In vivo biodistribution of (IPIP)-I-125 and internal dosimetry of (IPIP)-I-123 radioiodinated agents selective to the muscarinic acetylcholinergic receptor complex SO MEDICAL PHYSICS LA English DT Article DE biodistribution; iodine; internal dosimetry; muscarinic acetylcholinergic complex; radiopharmaceuticals; biokinetics; rat studies AB The development of new radioiodinated ligands for imaging the muscarinic acetylcholinergic complex (mAChR) using single photon emission computed tomography (SPECT) requires the evaluation of human organ doses prior to approval for human use. Animal biodistribution and excretion data were obtained and evaluated for IPIP, a new mAChR agent. Preliminary biodistribution studies were performed on four different stereoisomers of IPIP. A biokinetic model of the Z-(S)-IPIP stereoisomer was constructed for the rat and used to estimate the internal absorbed dose in humans based on an extrapolation of the rat model. The thyroid is the critical organ for this radiopharmaceutical, with an absorbed dose estimate of 2.4 mGy/MBq for both males and females, when labeled with I-123. Even when blocked, the thyroid is still the critical organ, yet with a 90% dose reduction. The heart and brain receive the next highest doses in both males and females. Effective dose estimates for the use of pure I-123-PIP in humans are 0.16 mSv/MBq for males and 0.14 mSv/MBq for females: The biodistribution studies of the Z-(S)-IPIP stereoisomer showed the most promise as a successful agent for imaging muscarinic receptor sites in the heart and brain. IPIP also demonstrated potential as a therapeutic radiopharmaceutical for some colon carcinomas where muscarinic receptor sites are expressed in the tumor cells. These results provide preliminary data for use of IPIP in clinical studies on humans. (C) 2000 American Association of Physicists in Medicine. C1 Univ Michigan, Sch Publ Hlth, Dept Environm & Ind Hlth, Ann Arbor, MI 48109 USA. Univ Michigan, Dept Nucl Med, Ann Arbor, MI 48109 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Breeden, WK (reprint author), Univ Michigan, Sch Publ Hlth, Dept Environm & Ind Hlth, Ann Arbor, MI 48109 USA. NR 19 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-2405 J9 MED PHYS JI Med. Phys. PD APR PY 2000 VL 27 IS 4 BP 778 EP 786 DI 10.1118/1.598941 PG 9 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 306UN UT WOS:000086615200020 PM 10798701 ER PT J AU Stocks, GM Los, VF Repetsky, SP Shatnii, TD AF Stocks, GM Los, VF Repetsky, SP Shatnii, TD TI Short-range and long-range magnetic order and phase diagram of systems with strong electron correlation SO METALLOFIZIKA I NOVEISHIE TEKHNOLOGII LA English DT Article DE magnetic ordering; coherent potential; density of electronic states; phase diagram; electrical conductivity ID ONE-BODY APPROXIMATION; HUBBARD-MODEL; INFINITE DIMENSIONS; SUPERCONDUCTORS; SEPARATION; FIELD AB In this work, the coherent-potential method based on the cluster expansion for Green's function of Be disordered system is offered to study the electron-energy spectrum and magnetic ordering in the systems with strong electron correlation. Magnetic phase diagram is drawn in variables of Coulomb-repulsion potential-electron concentration. With the help of short-range and long-range order parameters in orientation of magnetic moments, the boundaries of phase regions are determined. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NASU, Inst Magnetism, UA-03680 Kiev 142, Ukraine. Taras Shevchenko Kyyiv Natl Univ, UA-03022 Kiev 22, Ukraine. RP Stocks, GM (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Stocks, George Malcollm/Q-1251-2016 OI Stocks, George Malcollm/0000-0002-9013-260X NR 31 TC 1 Z9 1 U1 0 U2 3 PU NATL ACAD SCIENCES UKRAINE, INST METAL PHYSICS PI KIEV 142 PA 36 ACADEMICIAN VERNADSKY BLVD, KIEV 142 UA-252180, UKRAINE SN 1024-1809 J9 METALLOFIZ NOV TEKH+ JI Metallofiz. Nov. Tekhnol.-Met. Phys. Adv. Techn. PD APR PY 2000 VL 22 IS 4 BP 3 EP 12 PG 10 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA 319GG UT WOS:000087332700001 ER PT J AU Mazumder, P Trivedi, R Karma, A AF Mazumder, P Trivedi, R Karma, A TI A model of convection-induced oscillatory structure formation in peritectic alloys SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID DIRECTIONAL SOLIDIFICATION; CRYSTAL-GROWTH; THERMOSOLUTAL CONVECTION; HORIZONTAL TEMPERATURE; NATURAL-CONVECTION; BRIDGMAN GROWTH; SIMULATION; GALLIUM; SYSTEMS; SEGREGATION AB In the two-phase region of a peritectic system, experimental studies have shown that the primary phase (alpha) often forms a large treelike structure that is surrounded by the peritectic phase (beta). The formation of this novel structure has been attributed to the presence of convection in the liquid. Here, specific physical mechanisms of convection-induced treelike structure formation are proposed. A mathematical model based on advection-diffusion of solute, with prototype flows for advection, is presented and solved numerically to show that an oscillating fluid motion can give rise to a complex oscillatory, treelike structure. Three different regimes are established: diffusive, steady convective, and unsteady convective regimes. In the diffusive regime, a banded structure is predicted within a narrow composition range, and the spacing of the bands is dictated by the nucleation undercoolings of the two phases. Under steady convection, the primary phase transforms into the peritectic phase with a curved alpha:beta interface. Finally, in the presence of oscillating convection, a treelike shape of the primary phase is predicted, as observed experimentally. C1 Corning Inc, Corning, NY 14831 USA. Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. Iowa State Univ, Dept Mech Engn, Ames, IA 50011 USA. US DOE, Ames Lab, Ames, IA 50011 USA. Northeastern Univ, Dept Phys, Boston, MA 02115 USA. Northeastern Univ, Ctr Interdisciplinary Res Complex Syst, Boston, MA 02115 USA. RP Mazumder, P (reprint author), Corning Inc, Corning, NY 14831 USA. NR 52 TC 34 Z9 36 U1 0 U2 5 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 USA SN 1073-5623 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD APR PY 2000 VL 31 IS 4 BP 1233 EP 1246 DI 10.1007/s11661-000-0119-x PG 14 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 307BH UT WOS:000086633200019 ER PT J AU Norlund, CA Trivedi, R AF Norlund, CA Trivedi, R TI Eutectic interface configurations during melting SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID SELECTION AB Experimental studies are presented on the melting of a lamellar eutectic structure in a transparent model alloy system. Steady-state morphologies have been characterized for different dissolution rates. Both coupled and noncoupled melting of eutectic are observed. A diffusive model of coupled eutectic melting has been developed and compared with the experimental results. Because the eutectic spacing is fixed, the system is shown to select the shape so that the average position of the interface for the two phases remains isothermal. A comparison of the predicted shapes with the experimental data shows that the higher melting point phase adjusts its curvature to equate the average temperature of the two phases when the experimental conditions are in the coupled melting regime. The conditions for a coupled melting to be unstable are described for which one of the phases extends further into the liquid. When this extension is significant, a spherodization of the leading phase is observed. C1 Oregon Met, Albany, OR 97321 USA. US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. RP Norlund, CA (reprint author), Oregon Met, Albany, OR 97321 USA. NR 8 TC 6 Z9 6 U1 1 U2 3 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 USA SN 1073-5623 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD APR PY 2000 VL 31 IS 4 BP 1261 EP 1269 DI 10.1007/s11661-000-0121-3 PG 9 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 307BH UT WOS:000086633200021 ER PT J AU Wang, H Jiang, L Liaw, PK Brooks, CR Klarstrom, DL AF Wang, H Jiang, L Liaw, PK Brooks, CR Klarstrom, DL TI Infrared temperature mapping of ULTIMET alloy during high-cycle fatigue tests SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Mat Sci & Engn, Knoxville, TN 37996 USA. Haynes Int Inc, Technol, Kokomo, IN 46904 USA. RP Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Wang, Hsin/A-1942-2013 OI Wang, Hsin/0000-0003-2426-9867 NR 13 TC 38 Z9 39 U1 1 U2 4 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1073-5623 EI 1543-1940 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD APR PY 2000 VL 31 IS 4 BP 1307 EP 1310 DI 10.1007/s11661-000-0126-y PG 4 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 307BH UT WOS:000086633200026 ER PT J AU Mikrajuddin Shi, FG Nieh, TG Okuyama, K AF Mikrajuddin Shi, FG Nieh, TG Okuyama, K TI Electrical conduction in solid polymer electrolytes: temperature dependence mechanism SO MICROELECTRONICS JOURNAL LA English DT Article DE Arrhenius; VTF; fluctuation; melting point; critical temperature AB It is generally accepted that the electrical conduction in solid polymer electrolytes (PE) is strongly temperature dependent: an Arrhenius dependence is observed at low temperatures, while a non-Arrhenius Vogel-Tamman-Fulcher (VTF) behavior is seen at high temperatures. A theory is introduced, for the first time, for the electrical conduction of solid PE in the entire range of temperatures, by considering the fluctuation of the melting temperature and by the application of the statistical theory of gelation. The theory contains the expected Arrhenius and VTF dependence as the asymptotic limits at low and high temperatures, respectively. In addition, a critical transition temperature at which the electrical conductivity behavior changes from Arrhenius-like to VTF-like is determined analytically. This critical temperature is shown to increase linearly with the melting point of the PE. It is demonstrated that the theoretical results are in good agreement with the experimental evidence. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Hiroshima Univ, Fac Engn, Higashihiroshima 7398527, Japan. Univ Calif Irvine, Sch Engn, Irvine, CA 92697 USA. Univ Calif Lawrence Livermore Natl Lab, Mat & Chem Div, Livermore, CA 94551 USA. RP Okuyama, K (reprint author), Hiroshima Univ, Fac Engn, Higashihiroshima 7398527, Japan. RI Nieh, Tai-Gang/G-5912-2011; okuyama, kikuo/F-6092-2010 OI Nieh, Tai-Gang/0000-0002-2814-3746; NR 16 TC 0 Z9 0 U1 1 U2 8 PU ELSEVIER ADVANCED TECHNOLOGY PI OXFORD PA OXFORD FULFILLMENT CENTRE THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0026-2692 J9 MICROELECTR J JI Microelectron. J. PD APR PY 2000 VL 31 IS 4 BP 261 EP 265 PG 5 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology SC Engineering; Science & Technology - Other Topics GA 282AH UT WOS:000085193300006 ER PT J AU Kim, YH Borry, RW Iglesia, E AF Kim, YH Borry, RW Iglesia, E TI Genesis of methane activation sites in Mo-exchanged H-ZSM-5 catalysts SO MICROPOROUS AND MESOPOROUS MATERIALS LA English DT Article DE methane; Mo carburization; Mo/H-ZSM-5; Mo structure; pyrolysis ID MO/HZSM-5 CATALYSTS; REACTION-MECHANISM; AROMATIZATION; CONVERSION; BENZENE; DEHYDROGENATION; SAPO-34; ZEOLITE; PROPANE; CATIONS AB Exchanged (Mo2O7)(2-) dimers form during treatment in air of MoO3/H-ZSM-5 (Si/Al=14.3) physical mixtures at 773-973 K. The amount of water desorbed during exchange and the number of residual protons (measured by D-2-OH exchange) showed that each Mo6+ replaces 1.1 (+/- 0.1) protons in H-ZSM-5 (for Mo/Al<0.37). Al-27 NMR, X-ray absorption, and Raman spectra confirmed the proposed (Mo2O7)(2-) structure and its location at zeolite exchange sites. When the Mo content exceeds that required to form a MoOx bilayer on the external zeolite surface (Mo/Al approximate to 0.5), MoOx sublimes or forms Al-2(MoO4)(3) by extracting framework Al; Al-2(MoO4)(3) domains reduce slowly and lead to low CH4 reaction rates. The rate of hydrocarbon synthesis from CH4 at 930-973 K increased as exchanged MoOx dimers reduce and carburize during CH4 reactions. About 2.5 O atoms per Mo (+/-0.1) are removed as CO, CO2, and H2O during activation, suggesting that all but the zeolite framework oxygen atoms are removed during activation. Reduction and carburization rates depend on Mo content and on the rate of removal of CO, CO2, and H2O, which inhibit reduction/carburization steps. Hydrocarbons were not detected during the initial removal of about one O per Mo, but ethylene, benzene, naphthalene, and H-2 formation rates increased as larger amounts of O were removed during CH4 reactions. CH4 reactions require initial activation of CH4 on MoOx, but with the retention of C-atoms to form MoCx. These MoCx then activate C-H bonds and desorb the hydrocarbons formed, which then oligomerize and cyclize via rapid bifunctional pathways on H+ and MoCx sites within constrained ZSM-5 channels. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. Kunsan Natl Univ, Kunsan 573701, Chonbuk, South Korea. RP Iglesia, E (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Iglesia, Enrique/D-9551-2017 OI Iglesia, Enrique/0000-0003-4109-1001 NR 27 TC 90 Z9 91 U1 7 U2 41 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-1811 J9 MICROPOR MESOPOR MAT JI Microporous Mesoporous Mat. PD APR PY 2000 VL 35-6 BP 495 EP 509 DI 10.1016/S1387-1811(99)00245-0 PG 15 WC Chemistry, Applied; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary SC Chemistry; Science & Technology - Other Topics; Materials Science GA 304GH UT WOS:000086474900044 ER PT J AU Meldrum, A Boatner, LA Ewing, RC AF Meldrum, A Boatner, LA Ewing, RC TI A comparison of radiation effects in crystalline ABO(4)-type phosphates and silicates SO MINERALOGICAL MAGAZINE LA English DT Article DE zircon; monazite; metamietization; amorphization; radiation effects; plutonium; waste form ID WEAPONS PLUTONIUM; ZIRCON; MONAZITE; ORTHOSILICATES; AMORPHIZATION; CASCADES; CERAMICS; THORITE; DAMAGE; PHASE AB The effects of ion irradiation in the ABO(4)-type compounds were compared by performing experiments on four materials that include the most common crystal structures (monazite vs. zircon) and chemical compositions (phosphates Is, silicates) for these phases. Pure synthetic single crystals of ZrSiO4, monoclinic ThSiO4, LaPO4 and ScPO4 were irradiated using 800 keV Kr+ ions. Radiation damage accumulation was monitored as a function of temperature ill situ in a transmission electron microscope. The activation energies for recrystallization during irradiation were calculated to be 3.1-3.3 eV for the orthosilicates but only 1.0 1.5 eV for the isostructural orthophosphates. For the ion-beam-irradiated samples, the critical temperature, above which the recrystallization processes are faster than damage accumulation and amorphization cannot be induced, is >700 degrees C For ZrSiO4 but it is only 35 degrees C for LaPO4, At temperatures above 600 degrees C, zircon decomposed during irradiation into its component oxides (i.e. crystalline ZrO2 plus amorphous SiO2). The data are evaluated with respect to the proposed use of the orthophosphates and orthosilicates as host materials for the stabilization and disposal of high-level nuclear waste. The results show that zircon with 10 wt.% Pu would have to be maintained at temperatures in excess of 300 degrees C in order to prevent it from becoming completely amorphous. In contrast, a similar analysis for the orthophosphates implies that monazite-based waste forms would not become amorphous or undergo a phase decomposition. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ Michigan, Dept NE&RS, Ann Arbor, MI 49108 USA. RP Meldrum, A (reprint author), Univ Alberta, Dept Phys, Edmonton, AB T6G 2J1, Canada. RI Boatner, Lynn/I-6428-2013 OI Boatner, Lynn/0000-0002-0235-7594 NR 37 TC 53 Z9 55 U1 5 U2 17 PU MINERALOGICAL SOCIETY PI LONDON PA 41 QUEENS GATE, LONDON SW7 5HR, ENGLAND SN 0026-461X J9 MINERAL MAG JI Mineral. Mag. PD APR PY 2000 VL 64 IS 2 BP 185 EP 194 DI 10.1180/002646100549283 PG 10 WC Mineralogy SC Mineralogy GA 313TR UT WOS:000087015800003 ER PT J AU Mu, D Bessho, T Nechev, LV Chen, DJ Harris, TM Hearst, JE Sancar, A AF Mu, D Bessho, T Nechev, LV Chen, DJ Harris, TM Hearst, JE Sancar, A TI DNA interstrand cross-links induce futile repair synthesis in mammalian cell extracts SO MOLECULAR AND CELLULAR BIOLOGY LA English DT Article ID NUCLEOTIDE EXCISION NUCLEASE; REPLICATION PROTEIN-A; ESCHERICHIA-COLI; MISMATCH REPAIR; REMOVAL; STRAND; RECOMBINATION; MUTAGENICITY; MONOADDUCTS; XPF-ERCC1 AB DNA interstrand cross-links are induced by many carcinogens and anticancer drugs. It was previously shown that mammalian DNA excision repair nuclease makes dual incisions 5' to the cross-linked base of a psoralen cross-link, generating a gap of 22 to 28 nucleotides adjacent to the cross-link, We wished to find the fates of the gap and the cross-link in this complex structure under conditions conducive to repair synthesis, using cell extracts from wild-type and cross-linker-sensitive mutant cell lines. me found that the extracts from both types of strains filled in the gap but were severely defective in ligating the resulting nick and incapable of removing the cross-link. The net result was a futile damage-induced DNA synthesis which converted a gap into a nick without removing the damage. In addition, in this study, we showed that the structure-specific endonuclease, the XPF-ERCC1 heterodimer, acted as a 3'-to-5' exonuclease on cross-linked DNA in the presence of RPA Collectively, these observations shed some light on the cellular processing of DNA cross-links and reveal that cross-links induce a futile DNA synthesis cycle that mag constitute a signal for specific cellular responses to cross-linked DNA. C1 Univ N Carolina, Sch Med, Dept Biochem & Biophys, Chapel Hill, NC 27599 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Chem, Berkeley, CA 94720 USA. Vanderbilt Univ, Dept Chem, Nashville, TN 37232 USA. RP Sancar, A (reprint author), Univ N Carolina, Sch Med, Dept Biochem & Biophys, Chapel Hill, NC 27599 USA. RI Mu, David/E-8933-2011 OI Mu, David/0000-0002-7762-0182 FU NIGMS NIH HHS [R01 GM032833, GM32833] NR 37 TC 102 Z9 104 U1 0 U2 3 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 USA SN 0270-7306 J9 MOL CELL BIOL JI Mol. Cell. Biol. PD APR PY 2000 VL 20 IS 7 BP 2446 EP 2454 DI 10.1128/MCB.20.7.2446-2454.2000 PG 9 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 292RQ UT WOS:000085809200016 PM 10713168 ER PT J AU Chen, HM Schmeichel, KL Mian, IS Lelievre, S Petersen, OW Bissell, MJ AF Chen, HM Schmeichel, KL Mian, IS Lelievre, S Petersen, OW Bissell, MJ TI AZU-1: A candidate breast tumor suppressor and biomarker for tumor progression SO MOLECULAR BIOLOGY OF THE CELL LA English DT Article ID EPITHELIAL-CELL LINE; RECIPROCAL INTERACTIONS; EXPRESSION GENETICS; COILED COILS; PHENOTYPE; PROTEINS; GROWTH; CANCER; IMMUNOGLOBULIN; STROMELYSIN-1 AB To identify genes misregulated in the final stages of breast carcinogenesis, we performed differential display to compare the gene expression patterns of the human tumorigenic mammary epithelial cells, HMT-3522-T4-2, with those of their immediate premalignant progenitors, HMT-3522-S2. We identified a novel gene, called anti-zuai-1 (AZU-1), that was abundantly expressed in non- and premalignant cells and tissues but was appreciably reduced in breast tumor cell types and in primary tumors. The AZU-1 gene encodes an acidic 571-amino-acid protein containing at least two structurally distinct domains with potential protein-binding functions: an N-terminal serine and proline-rich domain with a predicted immunoglobulin-like fold and a C-terminal coiled-coil domain. In HMT-3522 cells, the bulk of AZU-1 protein resided in a detergent-extractable cytoplasmic pool and was present at much lower levels in tumorigenic T4-2 cells than in their nonmalignant counterparts. Reversion of the tumorigenic phenotype of T4-2 cells, by means described previously, was accompanied by the up-regulation of AZU-1. In addition, reexpression of AZU-1 in T4-2 cells, using viral vectors, was sufficient to reduce their malignant phenotype substantially, both in culture and in vivo. These results indicate that AZU-1 is a candidate breast tumor suppressor that may exert its effects by promoting correct tissue morphogenesis. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Panum Inst, Inst Med Anat, Struct Cell Biol Unit, DK-2100 Copenhagen, Denmark. RP Bissell, MJ (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. FU NCI NIH HHS [CA-64786-02, R37 CA064786, R01 CA064786] NR 41 TC 66 Z9 69 U1 0 U2 0 PU AMER SOC CELL BIOLOGY PI BETHESDA PA PUBL OFFICE, 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 1059-1524 J9 MOL BIOL CELL JI Mol. Biol. Cell PD APR PY 2000 VL 11 IS 4 BP 1357 EP 1367 PG 11 WC Cell Biology SC Cell Biology GA 304WZ UT WOS:000086508200018 PM 10749935 ER PT J AU Ally, MR AF Ally, MR TI Liquidus curves of NaNO3(aq) calculated from the modified adsorption isotherm model for aqueous electrolytes SO MONATSHEFTE FUR CHEMIE LA English DT Article DE activity coefficients; aqueous electrolytes; Brunauer-Emmett-Teller; BET; adsorption isotherm; eutectic ID CONCENTRATED-SOLUTIONS; BET MODEL; WATER AB The Stokes-Robinson modification of the Brunauer-Emmett-Teller (BET) adsorption isotherm is used to calculate the liquidus curve of NaNO3(aq) including the eutectic point and metastable phases. The method described here represents a simplified approach to predict the liquidus curves with sparse information. C1 Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. RP Ally, MR (reprint author), Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. NR 10 TC 11 Z9 11 U1 1 U2 1 PU SPRINGER-VERLAG WIEN PI VIENNA PA SACHSENPLATZ 4-6, PO BOX 89, A-1201 VIENNA, AUSTRIA SN 0026-9247 J9 MONATSH CHEM JI Mon. Chem. PD APR PY 2000 VL 131 IS 4 BP 341 EP 344 PG 4 WC Chemistry, Multidisciplinary SC Chemistry GA 311HL UT WOS:000086878600004 ER PT J AU Mason, T Taylor, A AF Mason, T Taylor, A TI NIST's contribution to neutron scattering in materials research - Response SO MRS BULLETIN LA English DT Letter C1 Oak Ridge Natl Lab, Oak Ridge, TN 37830 USA. Rutherford Appleton Lab, Chilton, England. RP Mason, T (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37830 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0883-7694 J9 MRS BULL JI MRS Bull. PD APR PY 2000 VL 25 IS 4 BP 6 EP 6 PG 1 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 305JF UT WOS:000086535800003 ER PT J AU Barhen, J Cogswell, R Protopopescu, V AF Barhen, J Cogswell, R Protopopescu, V TI Single-iteration training algorithm for multi-layer feed-forward neural networks SO NEURAL PROCESSING LETTERS LA English DT Article DE virtual input layer; neural network training; fast learning; SVD AB A new methodology for neural learning is presented. Only a single iteration is needed to train a feed-forward network with near-optimal results. This is achieved by introducing a key modification to the conventional multi-layer architecture. A virtual input layer is implemented, which is connected to the nominal input layer by a special nonlinear transfer function, and to the first hidden layer by regular (linear) synapses. A sequence of alternating direction singular value decompositions is then used to determine precisely the inter-layer synaptic weights. This computational paradigm exploits the known separability of the linear tinter-layer propagation) and nonlinear (neuron activation) aspects of information transfer within a neural network. Examples show that the trained neural networks generalize well. C1 Oak Ridge Natl Lab, Ctr Engn Sci Adv Res, Oak Ridge, TN 37831 USA. Monmouth Coll, Dept Math & Comp Sci, Monmouth, IL 61462 USA. NR 16 TC 5 Z9 5 U1 0 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 1370-4621 J9 NEURAL PROCESS LETT JI Neural Process. Lett. PD APR PY 2000 VL 11 IS 2 BP 113 EP 129 DI 10.1023/A:1009682730770 PG 17 WC Computer Science, Artificial Intelligence SC Computer Science GA 330WM UT WOS:000087984200003 ER PT J AU Starrfield, S Truran, JW Sparks, WM AF Starrfield, S Truran, JW Sparks, WM TI The nova outburst: thermonuclear runaways on degenerate dwarfs SO NEW ASTRONOMY REVIEWS LA English DT Article; Proceedings Paper CT Cataclysmic Variables: a 60th Birthday Symposium in Honour of Brian Warner CY APR 12-16, 1999 CL OXFORD UNIV, OXFORD, ENGLAND HO OXFORD UNIV ID LTE MODEL ATMOSPHERES; CLASSICAL NOVAE; PRIMITIVE METEORITES; LINE EMISSION; WHITE-DWARFS; V1974 CYGNI; NUCLEOSYNTHESIS; EVOLUTION; ABUNDANCES; OPACITIES AB Observational and theoretical studies of the outbursts of classical novae have provided critical insights into a broad range of astrophysical phenomena. Thermonuclear runaways (TNRs) in accreted hydrogen-rich envelopes on the white dwarf (WD) components of close binary systems constitute not only the outburst mechanism for a classical nova explosion, but also for recurrent novae and a fraction of the symbiotic novae explosions. Studies of the general characteristics of these explosions, both in our own galaxy and in neighboring galaxies of varying metallicity, can teach us about binary stellar evolution, while studies of the evolution of nova binary systems can constrain models for the (as yet unidentified) progenitors of Type Ia supernovae. Further, the empirical relation between the peak luminosity of a nova and the rate of decline, which presents a challenge to theoretical models, allows novae to be utilized as standard candles for distance determinations out to the Virgo Cluster. Extensive studies of novae with IUE and the resulting abundance determinations have revealed the existence of oxygen-neon white dwarfs in some systems. The high levels of enrichment of novae ejecta in elements ranging from carbon to sulfur confirm that there is significant dredge-up of matter from the core of the underlying white dwarf and enable novae to contribute to the chemical enrichment of the interstellar medium. Observations of the epoch of dust formation in the expanding shells of novae allow important constraints to be placed on the dust formation process and confirm that graphite, SiC, and SiO2 grains are formed by the outburst. It is possible that grains from novae were injected into the pre-solar nebula and can be identified with some of the pre-solar grains or "stardust" found in meteorites. Finally, gamma -ray observations during the first several years of their outburst, using the next generation of satellite obsrrvatories, could confirm the presence of decays from Be-7 and Na-22. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA. Univ Chicago, Enrico Fermi Inst, Dept Astron & Astrophys, Chicago, IL 60637 USA. Univ Calif Los Alamos Natl Lab, XNH, Los Alamos, NM 87545 USA. RP Starrfield, S (reprint author), Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA. NR 39 TC 21 Z9 21 U1 0 U2 1 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1387-6473 J9 NEW ASTRON REV JI New Astron. Rev. PD APR PY 2000 VL 44 IS 1-2 BP 81 EP 86 DI 10.1016/S1387-6473(00)00018-X PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 366RF UT WOS:000090017800016 ER PT J AU Pleune, TT Chopra, OK AF Pleune, TT Chopra, OK TI Using artificial neural networks to predict the fatigue life of carbon and low-alloy steels SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT ASME Pressure Vessels and Piping Conference (PVPC 97) CY JUL 27-31, 1997 CL ORLANDO, FLORIDA ID WATER AB The ASME Boiler and Pressure Vessel Code contains rules for the construction of nuclear power plant components. Figures I-9.1 through I-9.6 of Appendix I to Section III of the Code specify fatigue design curves for structural materials. However, the effects of light water reactor (LWR) coolant environments are not explicitly addressed by the Code design curves. Recent test data indicate significant decreases in the fatigue lives of carbon and low-alloy steels in LWR environments when five conditions are satisfied simultaneously. When applied strain range, temperature, dissolved oxygen in the water, and sulfur content of the steel are above a minimum threshold level, and the loading strain rate is below a threshold value, environmentally assisted fatigue occurs. For this study, a data base of 1036 fatigue tests was used to train an artificial neural network (ANN). Once the optimal ANN was designed, ANN were trained and used to predict fatigue life for specified sets of loading and environmental conditions. By finding patterns and trends in the data, the ANN can find the fatigue life for any set of conditions. Artificial neural networks show great potential for predicting environmentally assisted corrosion. Their main benefits are that the fit of the data is based purely on data and not on preconceptions and that the network can interpolate effects by learning trends and patterns when data are not available. (C) 2000 Published by Elsevier Science S.A. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Pleune, TT (reprint author), MIT, Dept Nucl Engn, 185 Albany St,Bldg NW22-197, Cambridge, MA 02139 USA. NR 13 TC 37 Z9 40 U1 0 U2 2 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD APR PY 2000 VL 197 IS 1-2 BP 1 EP 12 DI 10.1016/S0029-5493(99)00252-6 PG 12 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 292FJ UT WOS:000085783200002 ER PT J AU Khaleel, MA Simonen, FA AF Khaleel, MA Simonen, FA TI Effect of through-wall stress gradients on piping failure probabilities SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT ASME Pressure Vessels and Piping Conference (PVPC 97) CY JUL 27-31, 1997 CL ORLANDO, FLORIDA AB An approach has been developed that predicts leak and rupture probabilities of reactor piping in a structured parametric format. This approach applies the probabilistic fracture mechanics code pc-PRAISE (Piping Reliability Analysis Including Seismic Events) to address the mechanical and thermal fatigue life of piping. The probabilistic fracture mechanics model is applied to predict the relative effects of uniform stresses and through-thickness stress gradients on the reliability of stainless steel piping welds. Results generated using the numerical technique revealed that the calculated leak probabilities can be sensitive to the different types of stress gradients and to local stress concentrations. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Pacific NW Lab, Richland, WA 99352 USA. RP Khaleel, MA (reprint author), Pacific NW Lab, POB 999,902 Battelle Blvd, Richland, WA 99352 USA. OI khaleel, mohammad/0000-0001-7048-0749 NR 17 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD APR PY 2000 VL 197 IS 1-2 BP 89 EP 106 DI 10.1016/S0029-5493(99)00259-9 PG 18 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 292FJ UT WOS:000085783200008 ER PT J AU Khaleel, MA Simonen, FA AF Khaleel, MA Simonen, FA TI Effects of alternative inspection strategies on piping reliability SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT ASME Pressure Vessels and Piping Conference (PVPC 97) CY JUL 27-31, 1997 CL ORLANDO, FLORIDA AB This paper applies probabilistic fracture mechanics calculations to determine the effects of inspection on leak probabilities for piping. The approach has been to perform calculations in a structured parametric format, with the parameters selected to cover the range of pipe sizes, degradation mechanisms, operating stresses, and materials relevant to the piping systems of interest. In this paper, the calculations were intended to be generally applicable to mechanical and thermal fatigue of stainless steel piping. Specific areas of uncertainty addressed by the probabilistic calculations of this paper are the numbers of initial flaws, the distributions of flaw sizes, the crack growth rates for these initial flaws, and the probability of detection curves and inspection schedules that describe inservice inspections which are performed to detect these growing flaws. The effectiveness of an inspection strategy is quantified by the parameter 'Factor of Improvement', which is the relative increase in piping reliability due to a given inspection strategy as compared with the strategy of performing no inspection. The results of a systematic set of calculations are presented in this payer that address inspection effectiveness for operating stresses giving crack growth rates ranging from very low to very high. Inspection strategies are described that address three reference levels of ultrasonic inspection reliability, intervals between inspections ranging from 1 to 10 years, and both preservice and inservice inspections. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Pacific NW Lab, Virtual Protyping & Engn Silulat Lab, Richland, WA 99352 USA. RP Khaleel, MA (reprint author), Pacific NW Lab, Virtual Protyping & Engn Silulat Lab, POB 999,902 Battelle Blvd, Richland, WA 99352 USA. OI khaleel, mohammad/0000-0001-7048-0749 NR 18 TC 15 Z9 15 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD APR PY 2000 VL 197 IS 1-2 BP 115 EP 140 DI 10.1016/S0029-5493(99)00261-7 PG 26 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 292FJ UT WOS:000085783200010 ER PT J AU McElhaney, KL AF McElhaney, KL TI An analysis of check valve performance characteristics based on valve design SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT ASME Pressure Vessels and Piping Conference (PVPC 97) CY JUL 27-31, 1997 CL ORLANDO, FLORIDA AB Although it had been theorized by nuclear industry valve experts that the two most significant factors in assessing check valve performance were valve type (or design) and operating conditions, until recently, no data was available to support their assumptions. In co-operation with the Nuclear Industry Check Valve Group (NIC), Oak Ridge National Laboratory (ORNL) undertook a review and analysis of check valve failures recorded in the Institute of Nuclear Power Operations' (INPO) Nuclear Plant Reliability Data System (NPRDS). This study involved the characterization of failures according ro several parameters, including valve design (e.g. swing check, lift check). Since the valve design is not inherently included within the NPRDS engineering record for each component in the database, ORNL relied on input from NIC, valve manufacturers and catalogs to supply the missing information. As a result, nearly 60% of the 21 000 check valves listed in the NPRDS component database and 85% of the 838 failures occurring during 1991-1992 were identified according to valve design. This data provided the basis to perform previously unavailable cross-correlations between parameters such as valve design versus failure mode, valve design versus failure discovery method, population/failure distributions by valve design, etc. Performance assessments and predictions based on more specific sets of parameters (as opposed to generic check valve failure rates obtained from standard reference sources that generally ignore the valve design) should result in a significant impact on future nuclear plant operations, including inservice testing (IST) practices, maintenance, and probabilistic risk assessments (PRAs) by providing a means to calculate more appropriate relative (and ultimately absolute) failure rates for check valves. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Oak Ridge Natl Lab, Engn Technol Div, Performance Evaluat & Diagnost Res Grp, Oak Ridge, TN 37831 USA. RP McElhaney, KL (reprint author), Oak Ridge Natl Lab, Engn Technol Div, Performance Evaluat & Diagnost Res Grp, POB 2009, Oak Ridge, TN 37831 USA. NR 7 TC 5 Z9 7 U1 0 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD APR PY 2000 VL 197 IS 1-2 BP 169 EP 182 DI 10.1016/S0029-5493(99)00264-2 PG 14 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 292FJ UT WOS:000085783200013 ER PT J AU Richins, WD Fewell, TE Welland, HJ Sheely, HR AF Richins, WD Fewell, TE Welland, HJ Sheely, HR TI Shielded containers for radioactive waste using recycled contaminated metals SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT ASME Pressure Vessels and Piping Conference (PVPC 97) CY JUL 27-31, 1997 CL ORLANDO, FLORIDA AB A family of shielded containers constructed of recycled contaminated lead and stainless steel from the US Department of Energy (DOE) stockpile have been developed as a joint effort by the Idaho National Engineering and Environmental Laboratory and Lockheed Martin Energy Systems-Oak Ridge. The containers were designed primarily for the transportation and storage of 30- or 55-gallon drums of remote handled transuranic solid waste (RH-TRU). The use of recycled construction materials fulfills two purposes: (1) waste transportation and storage and (2) a reduction in the quantity of contaminated metals that require both storage and disposal. Currently, the DOE complex has millions of pounds of contaminated lead and stainless steel. Non-linear, dynamic finite element analyses were used to simulate the drop tests onto a rigid surface required for US Department of Transportation (DOT) 7A Type A certification. During and after these tests, the container contents must remain within the container and shielding must not be reduced. Loads in the major connections and strains in the stainless steel and lead were monitored as a function of time during dynamic impact analyses for three simulated drop orientations. Results were used to optimize the final design. Stainless steel and lead were found to have maximum strains well below ultimate levels except at an impact corner where additional deformation is acceptable. The predicted loads in the connections indicate that some yielding will occur but the containment and shielding will remain intact. The results provide assurance that the containers will pass the required DOT certification tests. The methods used can be applied to other waste shipping containers allowing for optimization of designs without the expense of actual impact testing. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. Lockheed Martin Energy Syst, Oak Ridge, TN 37831 USA. RP Richins, WD (reprint author), Idaho Natl Engn & Environm Lab, POB 1625,MS 3760, Idaho Falls, ID 83415 USA. NR 7 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD APR PY 2000 VL 197 IS 1-2 BP 183 EP 195 DI 10.1016/S0029-5493(99)00267-8 PG 13 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 292FJ UT WOS:000085783200014 ER PT J AU Park, JJ Butt, DP Beard, CA AF Park, JJ Butt, DP Beard, CA TI Review of liquid metal corrosion issues for potential containment materials for liquid lead and lead-bismuth eutectic spallation targets as a neutron source SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article ID OXIDATION BEHAVIOR; NIOBIUM; ALLOYS AB Lead (Pb) and lead-bismuth eutectic (44Pb-56Bi) have been the two primary candidate liquid metal target materials for the production of spallation neutrons. Selection of a container material for the liquid metal target will greatly affect the lifetime and safety of the target subsystem. For the liquid lead target, niobium-1 wt% zirconium (Nb-1Zr) is a candidate containment material for liquid lead, but its poor oxidation resistance has been a major concern. In this paper, the oxidation rate of Nb-1Zr was studied based on the calculations of thickness loss resulting from oxidation. According to these calculations, it appeared that uncoated Nb-1Zr may be used for a i-year operation at 900 degrees C at P-O2 =1 x 10(-6) Torr, but the same material may not be used in argon with 5-ppm oxygen. Coating technologies to reduce the oxidation of Nb-1Zr are reviewed, as are other candidate refractory metals such as molybdenum, tantalum, and tungsten. For the liquid lead-bismuth eutectic target, three candidate containment materials are suggested, based on a literature survey of the materials' compatibility and proton irradiation tests: Croloy 2-1/4, modified 9Cr-1Mo, and 12Cr-1Mo (HT-9) steel. These materials seem to be used only if the lead-bismuth is thoroughly deoxidized and treated with zirconium and magnesium. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Ceramatec Inc, Salt Lake City, UT 84119 USA. Univ Texas, Austin, TX 78712 USA. RP Park, JJ (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663,MS E508, Los Alamos, NM 87545 USA. RI Butt, Darryl/B-7480-2008 OI Butt, Darryl/0000-0003-4501-8864 NR 28 TC 42 Z9 45 U1 1 U2 17 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD APR PY 2000 VL 196 IS 3 BP 315 EP 325 DI 10.1016/S0029-5493(99)00303-9 PG 11 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 291HV UT WOS:000085729300006 ER PT J AU Borba, D Alper, B Budny, RV Fasoli, A Heeter, RF Kerner, W Sharapov, SE Smeulders, P AF Borba, D Alper, B Budny, RV Fasoli, A Heeter, RF Kerner, W Sharapov, SE Smeulders, P TI Beam driven Alfven eigenmodes and fishbones in JET SO NUCLEAR FUSION LA English DT Article ID NORMAL-MODE ANALYSIS; ION LOSSES; EXCITATION; TOKAMAKS; WAVES; PLASMAS; TFTR; PARTICLES AB Fast particle driven instabilities are investigated at low toroidal field B-0 approximate to 1 T in tritium, deuterium and hydrogen plasmas. Tritium, deuterium and hydrogen neutral beams with energies of 160, 140 and 110 keV were injected, respectively, into tritium, deuterium and hydrogen plasmas. The destabilization of Alfven eigenmodes was observed during injection of tritium beams into a tritium plasma and during the injection of deuterium beams into a deuterium plasma but not during the injection of hydrogen beams into a hydrogen plasma. At high beta, beta(N) = beta/(I-p/B(T)a) > 2.5, high amplitude fishbones were observed and appeared to be correlated with the degradation of confinement. C1 Jet Joint Undertaking, Abingdon OX14 3EA, Oxon, England. IST, EURATOM Assoc, Lisbon, Portugal. Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08544 USA. Ecole Polytech Fed Lausanne, Assoc Euratom Confederat Suisse, Ctr Rech Phys Plasmas, CH-1007 Lausanne, Switzerland. RP Borba, D (reprint author), Jet Joint Undertaking, Abingdon OX14 3EA, Oxon, England. RI Borba, Duarte/K-6148-2015 OI Borba, Duarte/0000-0001-5305-2857 NR 32 TC 17 Z9 17 U1 1 U2 3 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5, PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD APR PY 2000 VL 40 IS 4 BP 775 EP 783 DI 10.1088/0029-5515/40/4/303 PG 9 WC Physics, Fluids & Plasmas SC Physics GA 302PG UT WOS:000086373600003 ER PT J AU Baker, DR Wade, MR Sun, LY Petty, CC Luce, TC AF Baker, DR Wade, MR Sun, LY Petty, CC Luce, TC TI Dimensionless rho(*) scaling of particle transport in DIII-D L mode discharges SO NUCLEAR FUSION LA English DT Article ID ION-TRANSPORT; COEFFICIENTS; CONFINEMENT; ELECTRON; TOKAMAK AB The scaling of the transport rate of particles with normalized gyroradius has been measured for L mode discharges in the DIII-D tokamak. Both the helium diffusivity and the effective electron particle diffusivity were measured. In these L mode discharges, the particle diffusivities tend to scale like the ion thermal diffusivity, which scales between Bohm-like and Goldston-like. Non-zero inward pinch velocities are measured. Like the diffusivities, the pinch velocities increase with gyroradius. C1 Gen Atom Co, San Diego, CA USA. RP Baker, DR (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 25 TC 9 Z9 9 U1 0 U2 0 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5, PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD APR PY 2000 VL 40 IS 4 BP 799 EP 806 DI 10.1088/0029-5515/40/4/305 PG 8 WC Physics, Fluids & Plasmas SC Physics GA 302PG UT WOS:000086373600005 ER PT J AU Fournier, KB May, MJ Pacella, D Finkenthal, M Gregory, BC Goldstein, WH AF Fournier, KB May, MJ Pacella, D Finkenthal, M Gregory, BC Goldstein, WH TI Calculation of the radiative cooling coefficient for krypton in a low density plasma SO NUCLEAR FUSION LA English DT Article ID X-RAY; EXCITATION-AUTOIONIZATION; ATOMIC PROCESSES; FUSION PLASMAS; TOKAMAK; ITER; SPECTROMETER; DIAGNOSTICS; IMPURITIES; IONS AB The calculated radiative cooling rate coefficient for krypton as a trace impurity in low to moderate density plasmas is calculated. Collisional-radiative line emission, dielectronic recombination, radiative recombination and bremsstrahlung are considered as the principal radiative loss channels. Collisional-radiative models and the calculated charge state distribution for krypton have been benchmarked against measured ion brightness profiles in the FTU plasma. The calculated radiative loss rate is compared with two measurements of the radiative cooling coefficient for krypton in the FTU plasma. The measurements differ in how the krypton density profile is experimentally constrained. The krypton density profile is found (to be flat) from spectroscopic observations and (to be increasing radially outwards) from measurements of visible bremsstrahlung emission. The calculations show excellent agreement with the former set of measurements. Polynomial fits to the total radiative cooling coefficient are provided for ease of use in plasma modelling codes. Tables of ion emissivities are provided for use in modelling radiative losses from non-equilibrium plasmas. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. ENEA Sulla Fus, EURATOM Assoc, Ctr Ricerche Frascati, Rome, Italy. RP Fournier, KB (reprint author), Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. EM fournier2@llnl.gov NR 38 TC 23 Z9 23 U1 0 U2 1 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5, PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD APR PY 2000 VL 40 IS 4 BP 847 EP 864 DI 10.1088/0029-5515/40/4/309 PG 18 WC Physics, Fluids & Plasmas SC Physics GA 302PG UT WOS:000086373600009 ER PT J AU Nevins, WM Swain, R AF Nevins, WM Swain, R TI The thermonuclear fusion rate coefficient for p-B-11 reactions SO NUCLEAR FUSION LA English DT Article ID CROSS-SECTIONS AB Analytic approximations to the p-B-11 fusion rate coefficient suitable for use at both low (1 keV less than or equal to T less than or equal to 70 keV) and high (50 keV less than or equal to T less than or equal to 500 keV) temperatures are developed. Comparisons between these analytic approximations and calculations of the p-B-11 fusion rate coefficient based on numerical integration indicate that the overall error in these approximations is dominated by errors in the experimental measurement of the underlying p-B-11 fusion cross-sections. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Nevins, WM (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 21 TC 40 Z9 41 U1 1 U2 5 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5, PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD APR PY 2000 VL 40 IS 4 BP 865 EP 872 DI 10.1088/0029-5515/40/4/310 PG 8 WC Physics, Fluids & Plasmas SC Physics GA 302PG UT WOS:000086373600010 ER EF