FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Zhu, SJ Hamilton, JH Ramayya, AV Wang, MG Hwang, JK Jones, EF Peker, LK Babu, BRS Drafta, G Ma, WC Long, GL Zhu, LY Li, M Gan, CY Ginter, TN Kormicki, J Deng, JK Shi, DT Collins, WE Cole, JD Aryaeinejad, R Drigert, MW Rasmussen, JO Donangelo, R Gilat, J Asztalos, S Lee, IY Macchiavelli, AO Chu, SY Gregorich, KE Mohar, MF Stoyer, MA Lougheed, RW Moody, KJ Wild, JF Prussin, SG Ter-Akopian, GM Daniel, AV Oganessian, YT AF Zhu, SJ Hamilton, JH Ramayya, AV Wang, MG Hwang, JK Jones, EF Peker, LK Babu, BRS Drafta, G Ma, WC Long, GL Zhu, LY Li, M Gan, CY Ginter, TN Kormicki, J Deng, JK Shi, DT Collins, WE Cole, JD Aryaeinejad, R Drigert, MW Rasmussen, JO Donangelo, R Gilat, J Asztalos, S Lee, IY Macchiavelli, AO Chu, SY Gregorich, KE Mohar, MF Stoyer, MA Lougheed, RW Moody, KJ Wild, JF Prussin, SG Ter-Akopian, GM Daniel, AV Oganessian, YT TI Octupole correlations in neutron-rich La-145,La-147 nuclei: Coriolis-limit-coupling bands with aligned h(11/2) proton SO PHYSICAL REVIEW C LA English DT Article ID SPONTANEOUS FISSION; BARIUM ISOTOPES; DEFORMATION; CF-252; MASS AB Several new high-spin states are observed in the prompt gamma-rays emitted from the neutron-rich, odd-Z La-145,La-147 fragments produced in the spontaneous fission of Cf-252. Alternating parity bands are extended up to spins 41/2 and 43/2 in La-145,La-147, respectively. A new band completes the evidence for two sell: of parity doublets expected for octupole correlations. Eight B(E1)/B(E2) ratios (four new) between two bands in La-145 are all essentially constant and somewhat larger than similar ratios in Ba-143,Ba-144, where stable octupole deformation and/or correlations are reported. The new ratios out of the 31/2(-) levels in both nuclei show a sharp spike compared to other states, presumably from a strong reduction in E2 strengths in this backbending region. In 145La, collective bands show competition and coexistence between symmetric and asymmetric shapes. Band crossings occur in both nuclei around (h) over bar omega approximate to 0.26-0.30 MeV. Their backbends are associated with the alignment of two i(13/2) neutrons according to cranked shell model calculations. [S0556-2813(99)08402-2]. C1 Tsing Hua Univ, Dept Phys, Beijing 100084, Peoples R China. Vanderbilt Univ, Dept Phys, Nashville, TN 37235 USA. Oak Ridge Natl Lab, Joint Inst Heavy Ion Res, Oak Ridge, TN 37831 USA. Mississippi State Univ, Dept Phys, Mississippi State, MS 39762 USA. Fisk Univ, Dept Phys, Nashville, TN 37208 USA. Idaho Natl Engn Lab, Idaho Falls, ID 83415 USA. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Fed Rio de Janeiro, Rio De Janeiro, Brazil. Soreq Nucl Res Ctr, IL-70600 Yavne, Israel. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Berkeley, Berkeley, CA 94720 USA. Joint Nucl Res Inst, Flerov Lab Nucl React, Dubna, Russia. ORISE, UNISOR, Oak Ridge, TN 37831 USA. RP Zhu, SJ (reprint author), Tsing Hua Univ, Dept Phys, Beijing 100084, Peoples R China. RI Long, Gui Lu/B-1170-2008; Long, Gui Lu/B-8988-2014 OI Long, Gui Lu/0000-0002-9023-1579 NR 18 TC 55 Z9 59 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1999 VL 59 IS 3 BP 1316 EP 1323 DI 10.1103/PhysRevC.59.1316 PG 8 WC Physics, Nuclear SC Physics GA 177VY UT WOS:000079232800011 ER PT J AU Sohler, D Cederkall, J Lipoglavsek, M Dombradi, Z Gorska, M Persson, J Seweryniak, D Ahmad, I Atac, A Bark, RA Blomqvist, J Carpenter, MP Cederwall, B Davids, CN Fahlander, C Fischer, SM Grawe, H Hackman, G Janssens, RVF Johnson, A Kerek, A Klamra, W Kownacki, J Lister, CJ Mitarai, S Nisius, D Norlin, LO Nyberg, J Poli, G Reiter, P Ressler, JJ Roth, HA Schwartz, J Sletten, G Uusitalo, J Walters, WB Weiszflog, M AF Sohler, D Cederkall, J Lipoglavsek, M Dombradi, Z Gorska, M Persson, J Seweryniak, D Ahmad, I Atac, A Bark, RA Blomqvist, J Carpenter, MP Cederwall, B Davids, CN Fahlander, C Fischer, SM Grawe, H Hackman, G Janssens, RVF Johnson, A Kerek, A Klamra, W Kownacki, J Lister, CJ Mitarai, S Nisius, D Norlin, LO Nyberg, J Poli, G Reiter, P Ressler, JJ Roth, HA Schwartz, J Sletten, G Uusitalo, J Walters, WB Weiszflog, M TI Yrast states of the proton drip line nucleus Sb-106 SO PHYSICAL REVIEW C LA English DT Article ID NEUTRON; DECAY AB Yrast states of Sb-106 have been investigated in the Fe-54(Ni-58, alpha pn) reaction using in-beam gamma-spectroscopic methods and in the Cr-50(Ni-58,pn) reaction performing delayed gamma and conversion electron studies. A new isomeric state was found at 103 keV with t(1/2) = 232(21) ns. The number of start's and transitions in the proposed level scheme have been doubled. The experimental results are discussed within the framework of the shell model. [S0556-2813(99)08502-7]. C1 Inst Nucl Res, H-4001 Debrecen, Hungary. Royal Inst Technol, Dept Phys, S-10044 Stockholm, Sweden. Lund Univ, Dept Cosm & Subatom Phys, Lund, Sweden. Jozef Stefan Inst, Ljubljana, Slovenia. Gesell Schwerionenforsch mbH, Darmstadt, Germany. Univ Warsaw, Inst Phys Expt, PL-00325 Warsaw, Poland. Uppsala Univ, Dept Radiat Sci, Uppsala, Sweden. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Copenhagen, Niels Bohr Inst, DK-2100 Copenhagen, Denmark. Warsaw Univ, Heavy Ion Lab, Warsaw, Poland. Kyushu Univ, Dept Phys, Fukuoka 812, Japan. Uppsala Univ, Svedberg Lab, S-75105 Uppsala, Sweden. Univ Milan, Ist Fis Gen Applicata, I-20122 Milan, Italy. Univ Maryland, College Pk, MD 20742 USA. Chalmers, Dept Phys, S-41296 Gothenburg, Sweden. Gothenburg Univ, S-41124 Gothenburg, Sweden. RP Inst Nucl Res, POB 51, H-4001 Debrecen, Hungary. RI Ressler, Jennifer Jo/F-2279-2010; Dombradi, Zsolt/B-3743-2012; Cederwall, Bo/M-3337-2014; Carpenter, Michael/E-4287-2015 OI Cederwall, Bo/0000-0003-1771-2656; Carpenter, Michael/0000-0002-3237-5734 NR 16 TC 14 Z9 14 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9985 EI 2469-9993 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1999 VL 59 IS 3 BP 1324 EP 1327 DI 10.1103/PhysRevC.59.1324 PG 4 WC Physics, Nuclear SC Physics GA 177VY UT WOS:000079232800012 ER PT J AU Tanaka, N Suzuki, Y Varga, K Lovas, RG AF Tanaka, N Suzuki, Y Varga, K Lovas, RG TI Unbound states by analytic continuation in the coupling constant SO PHYSICAL REVIEW C LA English DT Article ID SHELL-MODEL CALCULATIONS; S-MATRIX; LIGHT-NUCLEI; ENERGY; B-9; RESONANCE; HE-5 AB The energies and widths of resonance states are determined by the analytic continuation of bound-state energies as functions of a potential strength parameter (''the coupling constant''). Various numerical examples show the applicability of the method to systems decaying to two- and three-body channels. The examples include unbound states of the nuclei He-5, Li-5, Be-9, and B-9, described in alpha+N and alpha+alpha+N microscopic cluster models. Some states considered are controversial. Here they are well defined, and their questionable features are understood to arise from their proximity to the complex-energy region of unphysical resonances with negative energies and positive widths. [S0556-2813(99)00103-X]. C1 Niigata Univ, Grad Sch Sci & Technol, Niigata 9502181, Japan. Niigata Univ, Dept Phys, Niigata 9502181, Japan. Hungarian Acad Sci, Inst Nucl Res, H-4001 Debrecen, Hungary. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. RP Tanaka, N (reprint author), Niigata Univ, Grad Sch Sci & Technol, Niigata 9502181, Japan. RI Varga, Kalman/A-7102-2013 NR 34 TC 56 Z9 59 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1999 VL 59 IS 3 BP 1391 EP 1399 DI 10.1103/PhysRevC.59.1391 PG 9 WC Physics, Nuclear SC Physics GA 177VY UT WOS:000079232800018 ER PT J AU Hoad, SJ Clarke, NM Freer, M Fulton, BR Fry, P Rae, WDM Wuosmaa, AH AF Hoad, SJ Clarke, NM Freer, M Fulton, BR Fry, P Rae, WDM Wuosmaa, AH TI Excitation function measurements for the C-12(Ne-20,C-12[0(2)(+)])Ne-20 reaction SO PHYSICAL REVIEW C LA English DT Article ID CONFIGURATIONS; MG-24; RESONANCE; STATE; C-12; O-16 AB An excitation function for the C-12(Ne-20,C-12[0(2)(+)])Ne-20 reaction was measured over the energy range E-c.m. = 22.5-31.9 MeV. An enhancement in the cross section was observed between E-c.m. = 24.5 and 10.5 MeV in both the C-12(0(2)(+)) + Ne-20(g.s.) and C-12(0(2)(+)) + Ne-20(2(+)) exit channels. Oscillatory angular distributions were observed at E-c.m. = 25.24, 26.56, 28.50, and 30.44 MeV acid the range of dominant angular moments involved at these energies was found to be centered on 14 (h) over bar,15 (h) over bar,16 (h) over bar, and 17 (h) over bar, respectively. Excitation functions were also measured for the C-12(Ne-20, C-12[3(-)])Ne-20* reaction. For the C-12(Ne-20, C-12[0(2)(+)])Ne-20 reaction the data were well described by the results of coupled channel calculations. [S0556-2813(99)07702-X]. C1 Univ Birmingham, Sch Phys & Astron, Birmingham B15 2TT, W Midlands, England. Univ Oxford, Dept Nucl Phys, Phys Nucl Lab, Oxford OX1 3RH, England. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. RP Hoad, SJ (reprint author), Univ Birmingham, Sch Phys & Astron, Birmingham B15 2TT, W Midlands, England. RI Freer, Martin/F-9379-2013 NR 25 TC 1 Z9 1 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1999 VL 59 IS 3 BP 1456 EP 1463 DI 10.1103/PhysRevC.59.1456 PG 8 WC Physics, Nuclear SC Physics GA 177VY UT WOS:000079232800025 ER PT J AU Kriss, BJ Hoibraten, S Holcomb, MD Kohler, MD Kraushaar, JJ Parry, S Ristinen, RA Saunders, A Smythe, WR Morris, CL Rawool-Sullivan, M Whitton, RM Brack, JT Gibson, EF Langenbrunner, JL AF Kriss, BJ Hoibraten, S Holcomb, MD Kohler, MD Kraushaar, JJ Parry, S Ristinen, RA Saunders, A Smythe, WR Morris, CL Rawool-Sullivan, M Whitton, RM Brack, JT Gibson, EF Langenbrunner, JL TI Pion-proton integral cross sections at T-pi=40 to 284 MeV SO PHYSICAL REVIEW C LA English DT Article ID PARTIAL-WAVE ANALYSIS; ELASTIC-SCATTERING; PI+P SCATTERING; ENERGY AB Integral cross sections for the scattering of pions by protons into angles greater than 30 degrees (lab) have been measured at a wide range of energies spanning the delta resonance using liquid hydrogen targets. Cross sections were measured for nip scattering at 40 energies from 39.8 to 283.9 MeV and for pi(-)p at 15 energies from 80.0 to 283.9 MeV. Comparisons with phase shift predictions from the Karlsruhe group show good agreement on resonance but significant deviations below 100 MeV. [S0556-2813(99)02903-9]. C1 Univ Colorado, Dept Phys, Phys Nucl Lab, Boulder, CO 80309 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. TRIUMF, Vancouver, BC V6T 2A3, Canada. Calif State Univ Sacramento, Sacramento, CA 95819 USA. Univ Minnesota, Minneapolis, MN 55455 USA. RP Kriss, BJ (reprint author), Lockheed Martin Mission Syst, 9970 Fed Dr M-S 01B, Colorado Springs, CO 80921 USA. NR 20 TC 6 Z9 6 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1999 VL 59 IS 3 BP 1480 EP 1487 DI 10.1103/PhysRevC.59.1480 PG 8 WC Physics, Nuclear SC Physics GA 177VY UT WOS:000079232800028 ER PT J AU van Heerden, IJ Palarczyk, M Wang, X Rapaport, J Prout, DL Goodman, CD Luther, BA Sugarbaker, E Taddeucci, TN Dehnhard, D Foster, CC Hicks, K Wang, L Yang, X O'Donnell, JM Ohnuma, H Park, BK Burleson, GR Blanchard, S AF van Heerden, IJ Palarczyk, M Wang, X Rapaport, J Prout, DL Goodman, CD Luther, BA Sugarbaker, E Taddeucci, TN Dehnhard, D Foster, CC Hicks, K Wang, L Yang, X O'Donnell, JM Ohnuma, H Park, BK Burleson, GR Blanchard, S TI Zero-degree differential cross sections and D-NN values for the O-17,O-18((p)over-right-arrow,(n)over-right-arrow)F-17,F-18 reactions at E-p=118MeV SO PHYSICAL REVIEW C LA English DT Article ID GAMOW-TELLER STRENGTH; BETA-DECAY; INTERMEDIATE ENERGIES; STANDARD MODEL; NUCLEI; SCATTERING; NEUTRON; O-16(P,N)F-16; EXCITATIONS; TESTS AB We present zero-degree differential cross sections and transverse spin-transfer coefficients D-NN(0-degrees) for the O-17.18((p)over-right-arrow,(n)over-right-arrow)F-17,F-18 reactions at E-p = 118 MeV.For the transition to the F-17(g.s.) to which several multipoles contribute, the measured D-NN(0-degrees) = -0.13 +/- 0.05 is used to separate the Fermi and Gamow-Teller contributions at 0-degrees. The empirical Gamow-Teller strengths and the Fermi strengths are employed to estimate the solar neutrino absorption cross section in O-17 and O-18. [S0556-2813(99)04503-3]. C1 Indiana Univ, Cyclotron Facil, Bloomington, IN 47405 USA. Univ Minnesota, Minneapolis, MN 55455 USA. Ohio Univ, Athens, OH 45701 USA. Ohio State Univ, Columbus, OH 43210 USA. Concordia Coll, Moorhead, MN 56562 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Chiba Inst Technol, Narashino, Chiba 2750023, Japan. New Mexico State Univ, Las Cruces, NM 88003 USA. Univ Western Cape, ZA-7535 Bellville, South Africa. RP van Heerden, IJ (reprint author), Indiana Univ, Cyclotron Facil, Bloomington, IN 47405 USA. NR 39 TC 0 Z9 0 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1999 VL 59 IS 3 BP 1488 EP 1496 DI 10.1103/PhysRevC.59.1488 PG 9 WC Physics, Nuclear SC Physics GA 177VY UT WOS:000079232800029 ER PT J AU Lestone, JP AF Lestone, JP TI Calculating fission rates at high spin: Incorporation of rotational degrees of freedom in thermodynamically fluctuating axially symmetric systems SO PHYSICAL REVIEW C LA English DT Article ID ION-INDUCED FISSION; NEUTRON EMISSION; FUSION-FISSION; PARTICLE-EMISSION; NUCLEAR-FISSION; TIME SCALES; DYNAMICS; MULTIPLICITIES; ENERGY AB The methods presently used to calculate fission rates fail to correctly take into account the rotational degrees of freedom of compound nuclei rotating in three dimensions. The statistical model code JOANNE has been modified to correctly calculate the fission rates of classical thermodynamically fluctuating axially symmetric systems rotating in three dimensions. With this new code it is possible to reproduce evaporation residue cross sections, fission cross sections, and prescission neutron multiplicities from O-induced reactions, without the use of large fission delay times or large values of the viscosity of heated nuclear matter. [S0556-2813(99)03103-9]. C1 Univ Washington, Nucl Phys Lab 354290, Seattle, WA 98195 USA. RP Lestone, JP (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 29 TC 49 Z9 49 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1999 VL 59 IS 3 BP 1540 EP 1544 DI 10.1103/PhysRevC.59.1540 PG 5 WC Physics, Nuclear SC Physics GA 177VY UT WOS:000079232800035 ER PT J AU Wang, F Sorge, H AF Wang, F Sorge, H TI Remnants of initial anisotropic high energy density domains in nucleus-nucleus collisions SO PHYSICAL REVIEW C LA English DT Article ID HEAVY-ION COLLISIONS; QUARK-GLUON PLASMA; MESON PRODUCTION; GEV/C; ENHANCEMENT; DYNAMICS; SULFUR AB Anisotropic high energy density domains may be formed at early stages of ultrarelativistic heavy ion collisions, e.g., due to phase transition dynamics or nonequilibrium phenomena like (mini)jets. Here we investigate hadronic observables resulting from an initially created anisotropic high energy density domain. Based on our studies using a transport model we find that the initial anisotropies are reflected in the freeze-out multiplicity distribution of both pions and kaons due to secondary hadronic rescattering. The anisotropy appears to be stronger for particles at high transverse momenta. The overall kaon multiplicity increases with large fluctuations of local energy densities, while no change has been found in the pion multiplicity. [S0556-2813(99)05103-1]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. SUNY Stony Brook, Dept Phys, Stony Brook, NY 11794 USA. RP Wang, F (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 36 TC 0 Z9 0 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1999 VL 59 IS 3 BP 1603 EP 1608 DI 10.1103/PhysRevC.59.1603 PG 6 WC Physics, Nuclear SC Physics GA 177VY UT WOS:000079232800042 ER PT J AU Sollfrank, J Heinz, U Sorge, H Xu, N AF Sollfrank, J Heinz, U Sorge, H Xu, N TI Thermal analysis of hadron multiplicities from relativistic quantum molecular dynamics SO PHYSICAL REVIEW C LA English DT Article ID NUCLEUS-NUCLEUS COLLISIONS; PB COLLISIONS; PARTICLE; EXPANSION; RATIOS; NUMBER AB Some questions arising in the application of the thermal model to hadron production in heavy ion collisions are studied. We do so by applying the thermal model of hadron production to particle yields calculated by the microscopic transport model RQMD (version 2.3). We study the bias of incomplete information about the final hadronic state on the extraction of thermal parameters. It is found that the subset of particles measured typically in the experiments looks more thermal than the complete set of stable particles. The hadrons which show the largest deviations from thermal behavior in RQMD (version 2.3) are the multistrange baryons and antibaryons. We also looked at the influence of rapidity cuts on the extraction of thermal parameters and found that they lead to different thermal parameters and larger disagreement between the RQMD yields and the thermal model. [S0556-2813(99)03603-1]. C1 Univ Regensburg, Inst Theoret Phys, D-93040 Regensburg, Germany. SUNY Stony Brook, Dept Phys, Stony Brook, NY 11794 USA. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Sollfrank, J (reprint author), Univ Regensburg, Inst Theoret Phys, D-93040 Regensburg, Germany. NR 41 TC 32 Z9 32 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1999 VL 59 IS 3 BP 1637 EP 1645 DI 10.1103/PhysRevC.59.1637 PG 9 WC Physics, Nuclear SC Physics GA 177VY UT WOS:000079232800045 ER PT J AU Kahana, DE Kahana, SH AF Kahana, DE Kahana, SH TI J/psi suppression in heavy ion collisions at the CERN Super Proton Synchrotron SO PHYSICAL REVIEW C LA English DT Article ID NUCLEUS-NUCLEUS COLLISIONS; HADRON-NUCLEUS; GEV-C; PARTICLE; MODEL; QUARK; FRAGMENTATION; DYNAMICS; CASCADE; PP AB We reexamine the production of J/psi and other charmonium states for a variety of target-projectile choices at the CERN Super Proton Synchrotron, in particular for the interesting comparison between S + U at 200 GeV/c and Pb + Pb at 158 GeV/c as observed in the experiments NA38 and NA50, respectively. For this study we use a newly constructed cascade code LUCIFER II, which yields acceptable descriptions of both hard and soft processes, specifically Drell-Yan and meson production. This code divides the ion-ion collision into an initial phase involving hard interactions of the original nucleons and no soft energy loss, followed after the meson formation time by a "normal" low energy cascade among the secondary particles. The modeling of the charmonium states differs from that of earlier workers in its unified treatment of the hidden charm meson spectrum, which is introduced from the outset as a set of coupled states {psi,chi',psi}. The result is a description of the NA38 and NA50 data in terms of a conventional, hadronic picture. The apparently anomalous suppression found in the most massive Pb + Pb system arises in the present simulation from three sources: destruction in the initial nucleon-nucleon cascade phase, use of coupled channels to exploit the larger breakup in the less bound chi' and psi' states, and comover interaction in the final low energy phase. [S0556-2813(99)01803-8]. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP 31 Pembrook Dr, Moscow 117901, Russia. OI Kahana, David Ewan/0000-0003-1266-9089 NR 54 TC 25 Z9 25 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9985 EI 2469-9993 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1999 VL 59 IS 3 BP 1651 EP 1662 DI 10.1103/PhysRevC.59.1651 PG 12 WC Physics, Nuclear SC Physics GA 177VY UT WOS:000079232800047 ER PT J AU Holl, A Maris, P Roberts, CD AF Holl, A Maris, P Roberts, CD TI Mean field exponents and small quark masses SO PHYSICAL REVIEW C LA English DT Article ID CHIRAL-SYMMETRY-BREAKING; FINITE-TEMPERATURE; MODEL; QCD; CHROMODYNAMICS; PHYSICS; PION AB We demonstrate that the restoration of chiral symmetry at finite T in a class of confining Dyson-Schwinger equation (DSE) models of QCD is a mean field transition, and that an accurate determination of the critical exponents using the chiral and thermal susceptibilities requires very small values of the current-quark mass: log(10)(m/m(u)) less than or similar to -5. Other classes of DSE models characterized by qualitatively different interactions also exhibit a mean field transition. Incipient in this observation is the suggestion that mean field exponents are a result of the gap equation's fermion substructure and not of the interaction. [S0556-2813(99)02303-1]. C1 Univ Rostock, Fachbereich Phys, D-18051 Rostock, Germany. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. RP Holl, A (reprint author), Univ Rostock, Fachbereich Phys, D-18051 Rostock, Germany. OI Roberts, Craig/0000-0002-2937-1361 NR 21 TC 31 Z9 31 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1999 VL 59 IS 3 BP 1751 EP 1755 DI 10.1103/PhysRevC.59.1751 PG 5 WC Physics, Nuclear SC Physics GA 177VY UT WOS:000079232800055 ER PT J AU Sharapov, EI Bowman, JD Crawford, BE Delheij, PPJ Haseyama, T Knudson, JN Lowie, LY Masaike, A Masuda, Y Matsuda, Y Mitchell, GE Penttila, SI Postma, H Roberson, NR Seestrom, SJ Stephenson, SL Yen, YF Yuan, VW AF Sharapov, EI Bowman, JD Crawford, BE Delheij, PPJ Haseyama, T Knudson, JN Lowie, LY Masaike, A Masuda, Y Matsuda, Y Mitchell, GE Penttila, SI Postma, H Roberson, NR Seestrom, SJ Stephenson, SL Yen, YF Yuan, VW TI Parity nonconservation in neutron resonances in Cs-133 SO PHYSICAL REVIEW C LA English DT Article ID COMPOUND-NUCLEUS; VIOLATION AB Spatial parity nonconservation (PNC) has been studied in the compound-nuclear states of Cs-134 by measuring the helicity dependence of the neutron total cross section. Transmission measurements on a thick Cs-133 target were performed by the time-of-flight method at the Manuel Lujan Neutron Scattering Center with a longitudinally polarized neutron beam in the energy range from 5 to 400 eV. A total of 28 new p-wave resonances were found, their neutron widths determined, and the PNC longitudinal asymmetries of the reso nance cross sections measured. The value obtained for the root-mean-square PNC element M=(0.06(-0.02)(+0.25)) meV in Cs-133 is the smallest among all targets studied. This value corresponds to a weak spreading width Gamma(w)=(0.006(-0.003)(+0.154)) x 10(-7) eV. [S0556-2813(99)03503-7]. C1 Joint Inst Nucl Res, Dubna 141980, Russia. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Duke Univ, Durham, NC 27708 USA. Triangle Univ Nucl Lab, Durham, NC 27708 USA. TRIUMF, Vancouver, BC V6T 2A3, Canada. Kyoto Univ, Dept Phys, Kyoto 60601, Japan. N Carolina State Univ, Raleigh, NC 27695 USA. Natl Lab High Energy Phys, Tsukuba, Ibaraki 305, Japan. Delft Univ Technol, NL-2600 GA Delft, Netherlands. RP Sharapov, EI (reprint author), Joint Inst Nucl Res, Dubna 141980, Russia. RI Matsuda, Yasuyuki/C-3007-2008 OI Matsuda, Yasuyuki/0000-0002-9847-3791 NR 27 TC 12 Z9 12 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1999 VL 59 IS 3 BP 1772 EP 1779 DI 10.1103/PhysRevC.59.1772 PG 8 WC Physics, Nuclear SC Physics GA 177VY UT WOS:000079232800058 ER PT J AU D'Alarcao, R Chowdhury, P Seabury, EH Walker, PM Wheldon, C Ahmad, I Carpenter, MP Hackman, G Janssens, RVF Khoo, TL Lister, CJ Nisius, D Reiter, P Seweryniak, D Wiedenhoever, I AF D'Alarcao, R Chowdhury, P Seabury, EH Walker, PM Wheldon, C Ahmad, I Carpenter, MP Hackman, G Janssens, RVF Khoo, TL Lister, CJ Nisius, D Reiter, P Seweryniak, D Wiedenhoever, I TI High-K isomers in neutron-rich hafnium nuclei at and beyond the stability line SO PHYSICAL REVIEW C LA English DT Article ID QUASI-PARTICLE STATES; BARRIER PENETRATION; HIGH-SPIN AB Pulsed U-238 and Pb-208 beams have been used to populate multi-quasiparticle high-K isomers in neutron-rich hafnium isotopes at and beyond the line of beta-stability, via inelastic excitation and transfer. Spectroscopic properties and configuration assignments of several new high-K isomers are compared with earlier theoretical predictions. A striking example of the robustness of the K quantum number is demonstrated by the observed competition between E1 and E3 decay modes in Hf-180, the heaviest stable isotope of the element. [S0556-2813(99)50503-7]. C1 Univ Massachusetts, Dept Phys, Lowell, MA 01854 USA. Univ Surrey, Dept Phys, Guildford GU2 5XH, Surrey, England. Argonne Natl Lab, Argonne, IL 60439 USA. RP D'Alarcao, R (reprint author), Univ Massachusetts, Dept Phys, Lowell, MA 01854 USA. RI Wheldon, Carl/F-9203-2013; Carpenter, Michael/E-4287-2015 OI Carpenter, Michael/0000-0002-3237-5734 NR 16 TC 48 Z9 48 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1999 VL 59 IS 3 BP R1227 EP R1231 DI 10.1103/PhysRevC.59.R1227 PG 5 WC Physics, Nuclear SC Physics GA 177VY UT WOS:000079232800001 ER PT J AU Abe, F Akimoto, H Akopian, A Albrow, MG Amadon, A Amendolia, SR Amidei, D Antos, J Aota, S Apollinari, G Arisawa, T Asakawa, T Ashmanskas, W Atac, M Azzi-Bacchetta, P Bacchetta, N Bagdasarov, S Bailey, MW de Barbaro, P Barbaro-Galtieri, A Barnes, VE Barnett, BA Barone, M Bauer, G Baumann, T Bedeschi, F Behrends, S Belforte, S Bellettini, G Bellinger, J Benjamin, D Bensinger, J Beretvas, A Berge, JP Berryhill, J Bertolucci, S Bettelli, S Bevensee, B Bhatti, A Biery, K Bigongiari, C Binkley, M Bisello, D Blair, RE Blocker, C Bloom, K Blusk, S Bodek, A Bokhari, W Bolla, G Bonushkin, Y Bortoletto, D Boudreau, J Breccia, L Bromberg, C Bruner, N Brunetti, R Buckley-Geer, E Budd, HS Burkett, K Busetto, G Byon-Wagner, A Byrum, KL Campbell, M Caner, A Carithers, W Carlsmith, D Cassada, J Castro, A Cauz, D Cerri, A Chang, PS Chang, PT Chao, HY Chapman, J Cheng, MT Chertok, M Chiarelli, G Chiou, CN Chlebana, F Christofek, L Cropp, R Chu, ML Cihangir, S Clark, AG Cobal, M Cocca, E Contreras, M Conway, J Daniels, T DeJongh, F Dell'Agnello, S Dell'Orso, M Demina, R Demortier, L Deninno, M Derwent, PF Devlin, T Dittmann, JR Donati, S Done, J Dorigo, T Eddy, N Einsweiler, K Elias, JE Ely, R Engels, E Erdmann, W Errede, D Errede, S Fan, Q Feild, RG Feng, Z Ferretti, C Fiori, I Flaugher, B Foster, GW Franklin, M Freeman, J Friedman, J Frisch, H Fukui, Y Gadomski, S Galeotti, S Gallinaro, M Ganel, O Garcia-Sciveres, M Garfinkel, AF Gay, C Geer, S Gerdes, DW Giannetti, P Giokaris, N Giromini, P Giusti, G Gold, M Gordon, A Goshaw, AT Gotra, Y Goulianos, K Grassmann, H Groer, L Grosso-Pilcher, C Guillian, G da Costa, JG Guo, RS Haber, C Hafen, E Hahn, SR Hamilton, R Handa, T Handler, R Hao, W Happacher, F Hara, K Hardman, AD Harris, RM Hartmann, F Hauser, J Hayashi, E Heinrich, J Heiss, A Hinrichsen, B Hoffman, KD Hohlmann, M Holck, C Hollebeek, R Holloway, L Huang, Z Huffman, BT Hughes, R Huston, J Huth, J Ikeda, H Incagli, M Incandela, J Introzzi, G Iwai, J Iwata, Y James, E Jensen, H Joshi, U Kajfasz, E Kambara, H Kamon, T Kaneko, T Karr, K Kasha, H Kato, Y Keaffaber, TA Kelley, K Kennedy, RD Kephart, R Kestenbaum, D Khazins, D Kikuchi, T Kim, BJ Kim, HS Kim, SH Kim, YK Kirsch, L Klimenko, S Knoblauch, D Koehn, P Kongeter, A Kondo, K Konigsberg, J Kordas, K Korytov, A Kovacs, E Kowald, W Kroll, J Kruse, M Kuhlmann, SE Kuns, E Kurino, K Kuwabara, T Laasanen, AT Lami, S Lammel, S Lamoureux, JI Lancaster, M Lanzoni, M Latino, G LeCompte, T Leone, S Lewis, JD Lindgren, M Liss, TM Liu, JB Liu, YC Lockyer, N Long, O Loreti, M Lucchesi, D Lukens, P Lusin, S Lys, J Maeshima, K Maksimovic, P Mangano, M Mariotti, M Marriner, JP Martignon, G Martin, A Matthews, JAJ Mazzanti, P McFarland, K McIntyre, P Melese, P Menguzzato, M Menzione, A Meschi, E Metzler, S Miao, C Miao, T Michail, G Miller, R Minato, H Miscetti, S Mishina, M Miyashita, S Moggi, N Moore, E Morita, Y Mukherjee, A Muller, T Murat, P Murgia, S Musy, M Nakada, H Nakaya, T Nakano, I Nelson, C Neuberger, D Newman-Holmes, C Ngan, CYP Nodulman, L Nomerotski, A Oh, SH Ohmoto, T Ohsugi, T Oishi, R Okabe, H Okusawa, T Olsen, J Pagliarone, C Paoletti, R Papadimitriou, V Pappas, SP Parashar, N Parri, A Patrick, J Pauletta, G Paulini, M Perazzo, A Pescara, L Peters, MD Phillips, TJ Piacentino, G Pillai, M Pitts, KT Plunkett, R Pompos, A Pondrom, L Proudfoot, J Ptohos, F Punzi, G Ragan, K Reher, D Reischl, M Ribon, A Rimondi, F Ristori, L Robertson, WJ Robinson, A Rodrigo, T Rolli, S Rosenson, L Roser, R Saab, T Sakumoto, WK Saltzberg, D Sansoni, A Santi, L Sato, H Schlabach, P Schmidt, EE Schmidt, MP Scott, A Scribano, A Segler, S Seidel, S Seiya, Y Semeria, F Shah, T Shapiro, MD Shaw, NM Shepard, PF Shibayama, T Shimojima, M Shochet, M Siegrist, J Sill, A Sinervo, P Singh, P Sliwa, K Smith, C Snider, FD Spalding, J Speer, T Sphicas, P Spinella, F Spiropulu, M Spiegel, L Stanco, L Steele, J Stefanini, A Strohmer, R Strologas, J Strumia, F Stuart, D Sumorok, K Suzuki, J Suzuki, T Takahashi, T Takano, T Takashima, R Takikawa, K Tanaka, M Tannenbaum, B Tartarelli, F Taylor, W Tecchio, M Teng, PK Teramoto, Y Terashi, K Tether, S Theriot, D Thomas, TL Thurman-Keup, R Timko, M Tipton, P Titov, A Tkaczyk, S Toback, D Tollefson, K Tollestrup, A Toyoda, H Trischuk, W de Troconiz, JF Truitt, S Tseng, J Turini, N Uchida, T Ukegawa, F Valls, J van den Brink, SC Vejcik, S Velev, G Vidal, R Vilar, R Vucinic, D Wagner, RG Wagner, RL Wahl, J Wallace, NB Walsh, AM Wang, C Wang, CH Wang, MJ Warburton, A Watanabe, T Watts, T Webb, R Wei, C Wenzel, H Wester, WC Wicklund, AB Wicklund, E Wilkinson, R Williams, HH Wilson, P Winer, BL Winn, D Wolinski, D Wolinski, J Worm, S Wu, X Wyss, J Yagil, A Yao, W Yasuoka, K Yeh, GP Yeh, P Yoh, J Yosef, C Yoshida, T Yu, I Zanetti, A Zetti, F Zucchelli, S AF Abe, F Akimoto, H Akopian, A Albrow, MG Amadon, A Amendolia, SR Amidei, D Antos, J Aota, S Apollinari, G Arisawa, T Asakawa, T Ashmanskas, W Atac, M Azzi-Bacchetta, P Bacchetta, N Bagdasarov, S Bailey, MW de Barbaro, P Barbaro-Galtieri, A Barnes, VE Barnett, BA Barone, M Bauer, G Baumann, T Bedeschi, F Behrends, S Belforte, S Bellettini, G Bellinger, J Benjamin, D Bensinger, J Beretvas, A Berge, JP Berryhill, J Bertolucci, S Bettelli, S Bevensee, B Bhatti, A Biery, K Bigongiari, C Binkley, M Bisello, D Blair, RE Blocker, C Bloom, K Blusk, S Bodek, A Bokhari, W Bolla, G Bonushkin, Y Bortoletto, D Boudreau, J Breccia, L Bromberg, C Bruner, N Brunetti, R Buckley-Geer, E Budd, HS Burkett, K Busetto, G Byon-Wagner, A Byrum, KL Campbell, M Caner, A Carithers, W Carlsmith, D Cassada, J Castro, A Cauz, D Cerri, A Chang, PS Chang, PT Chao, HY Chapman, J Cheng, MT Chertok, M Chiarelli, G Chiou, CN Chlebana, F Christofek, L Cropp, R Chu, ML Cihangir, S Clark, AG Cobal, M Cocca, E Contreras, M Conway, J Daniels, T DeJongh, F Dell'Agnello, S Dell'Orso, M Demina, R Demortier, L Deninno, M Derwent, PF Devlin, T Dittmann, JR Donati, S Done, J Dorigo, T Eddy, N Einsweiler, K Elias, JE Ely, R Engels, E Erdmann, W Errede, D Errede, S Fan, Q Feild, RG Feng, Z Ferretti, C Fiori, I Flaugher, B Foster, GW Franklin, M Freeman, J Friedman, J Frisch, H Fukui, Y Gadomski, S Galeotti, S Gallinaro, M Ganel, O Garcia-Sciveres, M Garfinkel, AF Gay, C Geer, S Gerdes, DW Giannetti, P Giokaris, N Giromini, P Giusti, G Gold, M Gordon, A Goshaw, AT Gotra, Y Goulianos, K Grassmann, H Groer, L Grosso-Pilcher, C Guillian, G da Costa, JG Guo, RS Haber, C Hafen, E Hahn, SR Hamilton, R Handa, T Handler, R Hao, W Happacher, F Hara, K Hardman, AD Harris, RM Hartmann, F Hauser, J Hayashi, E Heinrich, J Heiss, A Hinrichsen, B Hoffman, KD Hohlmann, M Holck, C Hollebeek, R Holloway, L Huang, Z Huffman, BT Hughes, R Huston, J Huth, J Ikeda, H Incagli, M Incandela, J Introzzi, G Iwai, J Iwata, Y James, E Jensen, H Joshi, U Kajfasz, E Kambara, H Kamon, T Kaneko, T Karr, K Kasha, H Kato, Y Keaffaber, TA Kelley, K Kennedy, RD Kephart, R Kestenbaum, D Khazins, D Kikuchi, T Kim, BJ Kim, HS Kim, SH Kim, YK Kirsch, L Klimenko, S Knoblauch, D Koehn, P Kongeter, A Kondo, K Konigsberg, J Kordas, K Korytov, A Kovacs, E Kowald, W Kroll, J Kruse, M Kuhlmann, SE Kuns, E Kurino, K Kuwabara, T Laasanen, AT Lami, S Lammel, S Lamoureux, JI Lancaster, M Lanzoni, M Latino, G LeCompte, T Leone, S Lewis, JD Lindgren, M Liss, TM Liu, JB Liu, YC Lockyer, N Long, O Loreti, M Lucchesi, D Lukens, P Lusin, S Lys, J Maeshima, K Maksimovic, P Mangano, M Mariotti, M Marriner, JP Martignon, G Martin, A Matthews, JAJ Mazzanti, P McFarland, K McIntyre, P Melese, P Menguzzato, M Menzione, A Meschi, E Metzler, S Miao, C Miao, T Michail, G Miller, R Minato, H Miscetti, S Mishina, M Miyashita, S Moggi, N Moore, E Morita, Y Mukherjee, A Muller, T Murat, P Murgia, S Musy, M Nakada, H Nakaya, T Nakano, I Nelson, C Neuberger, D Newman-Holmes, C Ngan, CYP Nodulman, L Nomerotski, A Oh, SH Ohmoto, T Ohsugi, T Oishi, R Okabe, H Okusawa, T Olsen, J Pagliarone, C Paoletti, R Papadimitriou, V Pappas, SP Parashar, N Parri, A Patrick, J Pauletta, G Paulini, M Perazzo, A Pescara, L Peters, MD Phillips, TJ Piacentino, G Pillai, M Pitts, KT Plunkett, R Pompos, A Pondrom, L Proudfoot, J Ptohos, F Punzi, G Ragan, K Reher, D Reischl, M Ribon, A Rimondi, F Ristori, L Robertson, WJ Robinson, A Rodrigo, T Rolli, S Rosenson, L Roser, R Saab, T Sakumoto, WK Saltzberg, D Sansoni, A Santi, L Sato, H Schlabach, P Schmidt, EE Schmidt, MP Scott, A Scribano, A Segler, S Seidel, S Seiya, Y Semeria, F Shah, T Shapiro, MD Shaw, NM Shepard, PF Shibayama, T Shimojima, M Shochet, M Siegrist, J Sill, A Sinervo, P Singh, P Sliwa, K Smith, C Snider, FD Spalding, J Speer, T Sphicas, P Spinella, F Spiropulu, M Spiegel, L Stanco, L Steele, J Stefanini, A Strohmer, R Strologas, J Strumia, F Stuart, D Sumorok, K Suzuki, J Suzuki, T Takahashi, T Takano, T Takashima, R Takikawa, K Tanaka, M Tannenbaum, B Tartarelli, F Taylor, W Tecchio, M Teng, PK Teramoto, Y Terashi, K Tether, S Theriot, D Thomas, TL Thurman-Keup, R Timko, M Tipton, P Titov, A Tkaczyk, S Toback, D Tollefson, K Tollestrup, A Toyoda, H Trischuk, W de Troconiz, JF Truitt, S Tseng, J Turini, N Uchida, T Ukegawa, F Valls, J van den Brink, SC Vejcik, S Velev, G Vidal, R Vilar, R Vucinic, D Wagner, RG Wagner, RL Wahl, J Wallace, NB Walsh, AM Wang, C Wang, CH Wang, MJ Warburton, A Watanabe, T Watts, T Webb, R Wei, C Wenzel, H Wester, WC Wicklund, AB Wicklund, E Wilkinson, R Williams, HH Wilson, P Winer, BL Winn, D Wolinski, D Wolinski, J Worm, S Wu, X Wyss, J Yagil, A Yao, W Yasuoka, K Yeh, GP Yeh, P Yoh, J Yosef, C Yoshida, T Yu, I Zanetti, A Zetti, F Zucchelli, S TI Measurement of Z(0) and Drell-Yan production cross sections using dimuons in (p)over-bar-p collisions at root s=1.8TeV SO PHYSICAL REVIEW D LA English DT Article ID TOP-QUARK PRODUCTION; QED RADIATIVE-CORRECTIONS; UNIVERSAL MONTE-CARLO; = 1.8 TEV; P(P)OVER-BAR COLLISIONS; W-BOSON; PARTON DISTRIBUTIONS; PBARP COLLISIONS; K-FACTOR; DILEPTONS AB We present a measurement of Z(0) boson and Drell-Yan production cross sections in (p) over bar p collisions at root s = 1.8 TeV using a sample of 107 pb(-1) accumulated by the Collider Detector at Fermilab. The Drell-Yan cross section is measured in the mass range of M-mu mu>40 GeV/c(2). We compare the measurements with the predictions of quantum chromodynamics in both leading order and next-to-leading order, incorporating the recent parton distribution functions. The measurements are consistent with the standard model expectations. [S0556-2821(99)01603-3]. C1 Kek Nat Lab High Energy Phys, Tsukuba, Ibaraki 305, Japan. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Bologna, Ist Nazl Fis Nucl, I-40127 Bologna, Italy. Brandeis Univ, Waltham, MA 02254 USA. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. Univ Chicago, Chicago, IL 60637 USA. Duke Univ, Durham, NC 27708 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Florida, Gainesville, FL 32611 USA. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Univ Geneva, CH-1211 Geneva 4, Switzerland. Harvard Univ, Cambridge, MA 02138 USA. Hiroshima Univ, Higashihiroshima 724, Japan. Univ Illinois, Urbana, IL 61801 USA. McGill Univ, Inst Particle Phys, Montreal, PQ H3A 2T8, Canada. Univ Toronto, Toronto, ON M5S 1A7, Canada. Johns Hopkins Univ, Baltimore, MD 21218 USA. Univ Karlsruhe, Inst Expt Kernphys, D-76128 Karlsruhe, Germany. Kek Nat Lab High Energy Phys, Tsukuba, Ibaraki 305, Japan. Ernest Orlando Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. MIT, Cambridge, MA 02139 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Michigan State Univ, E Lansing, MI 48824 USA. Univ New Mexico, Albuquerque, NM 87131 USA. Ohio State Univ, Columbus, OH 43210 USA. Osaka City Univ, Osaka 588, Japan. Univ Padua, Ist Nazl Fis Nucl, Sez Padova, I-35131 Padua, Italy. Univ Penn, Philadelphia, PA 19104 USA. Univ Pisa, Ist Nazl Fis Nucl, I-56100 Pisa, Italy. Scuola Normale Super Pisa, I-56100 Pisa, Italy. Univ Pittsburgh, Pittsburgh, PA 15260 USA. Purdue Univ, W Lafayette, IN 47907 USA. Univ Rochester, Rochester, NY 14627 USA. Rockefeller Univ, New York, NY 10021 USA. Rutgers State Univ, Piscataway, NJ 08855 USA. Acad Sinica, Taipei 11530, Taiwan. Texas A&M Univ, College Stn, TX 77843 USA. Texas Tech Univ, Lubbock, TX 79409 USA. Univ Trieste, Ist Nazl Fis Nucl, Udine, Italy. Univ Tsukuba, Tsukuba, Ibaraki 315, Japan. Tufts Univ, Medford, MA 02155 USA. Waseda Univ, Tokyo 169, Japan. Univ Wisconsin, Madison, WI 53706 USA. Yale Univ, New Haven, CT 06520 USA. RP Abe, F (reprint author), Kek Nat Lab High Energy Phys, Tsukuba, Ibaraki 305, Japan. RI Introzzi, Gianluca/K-2497-2015; Lancaster, Mark/C-1693-2008; Vucinic, Dejan/C-2406-2008; Nomerotski, Andrei/A-5169-2010; Azzi, Patrizia/H-5404-2012; Punzi, Giovanni/J-4947-2012; Chiarelli, Giorgio/E-8953-2012; Warburton, Andreas/N-8028-2013; Paulini, Manfred/N-7794-2014 OI Introzzi, Gianluca/0000-0002-1314-2580; Azzi, Patrizia/0000-0002-3129-828X; Punzi, Giovanni/0000-0002-8346-9052; Chiarelli, Giorgio/0000-0001-9851-4816; Warburton, Andreas/0000-0002-2298-7315; Paulini, Manfred/0000-0002-6714-5787 NR 34 TC 22 Z9 22 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAR 1 PY 1999 VL 59 IS 5 AR 052002 DI 10.1103/PhysRevD.59.052002 PG 15 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 173BN UT WOS:000078961200003 ER PT J AU Abe, K Abe, K Abe, T Adam, I Akagi, T Allen, NJ Arodzero, A Ash, WW Aston, D Baird, KG Baltay, C Band, HR Barakat, MB Bardon, O Barklow, TL Bauer, JM Bellodi, G Ben-David, R Benvenuti, AC Bilei, GM Bisello, D Blaylock, G Bogart, JR Bolen, B Bower, GR Brau, JE Breidenbach, M Bugg, WM Burke, D Burnett, TH Burrows, PN Calcaterra, A Caldwell, DO Calloway, D Camanzi, B Carpinelli, M Cassell, R Castaldi, R Castro, A Cavalli-Sforza, M Chou, A Church, E Cohn, HO Coller, JA Convery, MR Cook, V Cotton, R Cowan, RF Coyne, DG Crawford, G Damerell, CJS Danielson, MN Daoudi, M de Groot, N Dell'Orso, R Dervan, PJ de Sangro, R Dima, M D'Oliveira, A Dong, DN Du, PYC Dubois, R Eisenstein, BI Eschenburg, V Etzion, E Fahey, S Falciai, D Fan, C Fernandez, JP Fero, MJ Flood, K Frey, R Gillman, T Gladding, G Gonzalez, S Hart, EL Harton, JL Hasan, A Hasuko, K Hedges, SJ Hertzbach, SS Hildreth, MD Huber, J Huffer, ME Hughes, EW Huynh, X Hwang, H Iwasaki, M Jackson, DJ Jacques, P Jaros, JA Jiang, ZY Johnson, AS Johnson, JR Johnson, RA Junk, T Kajikawa, R Kalelkar, M Kamyshkov, Y Kang, HJ Karliner, I Kawahara, H Kim, YD King, R King, ME Kofler, RR Krishna, NM Kroeger, RS Langston, M Lath, A Leith, DWG Lia, V Lin, CJS Liu, X Liu, MX Loreti, M Lu, A Lynch, HL Ma, J Mancinelli, G Manly, S Mantovani, G Markiewicz, TW Maruyama, T Masuda, H Mazzucato, E McKemey, AK Meadows, BT Menegatti, G Messner, R Mockett, PM Moffeit, KC Moore, TB Morii, M Muller, D Murzin, V Nagamine, T Narita, S Nauenberg, U Neal, H Nussbaum, M Oishi, N Onoprienko, D Osborne, LS Panvini, RS Park, H Park, CH Pavel, TJ Peruzzi, I Piccolo, M Piemontese, L Pieroni, E Pitts, KT Plano, RJ Prepost, R Prescott, CY Punkar, GD Quigley, J Ratcliff, BN Reeves, TW Reidy, J Reinertsen, PL Rensing, PE Rochester, LS Rowson, PC Russell, JJ Saxton, OH Schalk, T Schindler, RH Schumm, BA Schwiening, J Sen, S Serbo, VV Shaevitz, MH Shank, JT Shapiro, G Sherden, DJ Shmakov, KD Simopoulos, C Sinev, NB Smith, SR Smy, MB Snyder, JA Staengle, H Stahl, A Stamer, P Steiner, R Steiner, H Strauss, MG Su, D Suekane, F Sugiyama, A Suzuki, S Swartz, M Szumilo, A Takahashi, T Taylor, FE Thom, J Torrence, E Toumbas, NK Trandafir, AI Turk, JD Usher, T Vannini, C Va'vra, J Vella, E Venuti, JP Verdier, R Verdini, PG Wagner, SR Wagner, DL Waite, AP Walston, S Wang, J Ward, C Watts, SJ Weidemann, AW Weiss, ER Whitaker, JS White, SL Wickens, FJ Williams, B Williams, DC Williams, SH Willocq, S Wilson, RJ Wisniewski, WJ Wittlin, JL Woods, M Word, GB Wright, TR Wyss, J Yamamoto, RK Yamartino, JM Yang, X Yashima, J Yellin, SJ Young, CC Yuta, H Zapalac, G Zdarko, RW Zhou, J AF Abe, K Abe, K Abe, T Adam, I Akagi, T Allen, NJ Arodzero, A Ash, WW Aston, D Baird, KG Baltay, C Band, HR Barakat, MB Bardon, O Barklow, TL Bauer, JM Bellodi, G Ben-David, R Benvenuti, AC Bilei, GM Bisello, D Blaylock, G Bogart, JR Bolen, B Bower, GR Brau, JE Breidenbach, M Bugg, WM Burke, D Burnett, TH Burrows, PN Calcaterra, A Caldwell, DO Calloway, D Camanzi, B Carpinelli, M Cassell, R Castaldi, R Castro, A Cavalli-Sforza, M Chou, A Church, E Cohn, HO Coller, JA Convery, MR Cook, V Cotton, R Cowan, RF Coyne, DG Crawford, G Damerell, CJS Danielson, MN Daoudi, M de Groot, N Dell'Orso, R Dervan, PJ de Sangro, R Dima, M D'Oliveira, A Dong, DN Du, PYC Dubois, R Eisenstein, BI Eschenburg, V Etzion, E Fahey, S Falciai, D Fan, C Fernandez, JP Fero, MJ Flood, K Frey, R Gillman, T Gladding, G Gonzalez, S Hart, EL Harton, JL Hasan, A Hasuko, K Hedges, SJ Hertzbach, SS Hildreth, MD Huber, J Huffer, ME Hughes, EW Huynh, X Hwang, H Iwasaki, M Jackson, DJ Jacques, P Jaros, JA Jiang, ZY Johnson, AS Johnson, JR Johnson, RA Junk, T Kajikawa, R Kalelkar, M Kamyshkov, Y Kang, HJ Karliner, I Kawahara, H Kim, YD King, R King, ME Kofler, RR Krishna, NM Kroeger, RS Langston, M Lath, A Leith, DWG Lia, V Lin, CJS Liu, X Liu, MX Loreti, M Lu, A Lynch, HL Ma, J Mancinelli, G Manly, S Mantovani, G Markiewicz, TW Maruyama, T Masuda, H Mazzucato, E McKemey, AK Meadows, BT Menegatti, G Messner, R Mockett, PM Moffeit, KC Moore, TB Morii, M Muller, D Murzin, V Nagamine, T Narita, S Nauenberg, U Neal, H Nussbaum, M Oishi, N Onoprienko, D Osborne, LS Panvini, RS Park, H Park, CH Pavel, TJ Peruzzi, I Piccolo, M Piemontese, L Pieroni, E Pitts, KT Plano, RJ Prepost, R Prescott, CY Punkar, GD Quigley, J Ratcliff, BN Reeves, TW Reidy, J Reinertsen, PL Rensing, PE Rochester, LS Rowson, PC Russell, JJ Saxton, OH Schalk, T Schindler, RH Schumm, BA Schwiening, J Sen, S Serbo, VV Shaevitz, MH Shank, JT Shapiro, G Sherden, DJ Shmakov, KD Simopoulos, C Sinev, NB Smith, SR Smy, MB Snyder, JA Staengle, H Stahl, A Stamer, P Steiner, R Steiner, H Strauss, MG Su, D Suekane, F Sugiyama, A Suzuki, S Swartz, M Szumilo, A Takahashi, T Taylor, FE Thom, J Torrence, E Toumbas, NK Trandafir, AI Turk, JD Usher, T Vannini, C Va'vra, J Vella, E Venuti, JP Verdier, R Verdini, PG Wagner, SR Wagner, DL Waite, AP Walston, S Wang, J Ward, C Watts, SJ Weidemann, AW Weiss, ER Whitaker, JS White, SL Wickens, FJ Williams, B Williams, DC Williams, SH Willocq, S Wilson, RJ Wisniewski, WJ Wittlin, JL Woods, M Word, GB Wright, TR Wyss, J Yamamoto, RK Yamartino, JM Yang, X Yashima, J Yellin, SJ Young, CC Yuta, H Zapalac, G Zdarko, RW Zhou, J TI Production of pi(+), K(+), K(0), K*(0), phi, p and Lambda(0) in hadronic Z(0) decays SO PHYSICAL REVIEW D LA English DT Article ID QCD JETS; PHYSICS; SLD; EVENTS; QUARK AB We have measured the differential production cross sections as a function of scaled momentum x(p)=2p/E(c.m.) of the identified hadron species pi(+), K(+), K(0), K(*0), phi, p, Lambda(0), and of the corresponding antihadron species in inclusive hadronic Z(0) decays, as well as separately for Z(0) decays into light (u, d, s), c and b flavors. Clear flavor dependences are observed, consistent with expectations based upon previously measured production and decay properties of heavy hadrons. These results were used to test the QCD predictions of Gribov and Lipatov, the predictions of QCD in the modified leading logarithm approximation with the ansatz of local parton-hadron duality, and the predictions of three fragmentation models. The ratios of production of different hadron species were also measured as a function of x(p) and were used to study the suppression of strange meson, strange and non-strange baryon, and vector meson production in the jet fragmentation process. The light-flavor results provide improved tests of the above predictions, as they remove the contribution of heavy hadron production and decay from that of the rest of the fragmentation process. In addition we have compared hadron and antihadron production as a function of x(p) in light quark (as opposed to antiquark) jets. Differences are observed at high x(p), providing direct evidence that higher-momentum hadrons are more likely to contain a primary quark or antiquark. The differences for pseudoscalar and vector kaons provide new measurements of strangeness suppression for high-x(p) fragmentation products. [S0556-2821(99)06101-9]. C1 Aomori Univ, Aomori City 030, Japan. Adelphi Univ, Garden City, NY 11530 USA. Ist Nazl Fis Nucl, Sez Bologna, I-40126 Bologna, Italy. Brunel Univ, Uxbridge UB8 3PH, Middx, England. Boston Univ, Boston, MA 02215 USA. Univ Cincinnati, Cincinnati, OH 45221 USA. Univ Colorado, Boulder, CO 80309 USA. Columbia Univ, Nevis Labs, Irvington, NY 10533 USA. Colorado State Univ, Ft Collins, CO 80523 USA. Ist Nazl Fis Nucl, Sez Ferrara, I-44100 Ferrara, Italy. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Univ Illinois, Urbana, IL 61801 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Phys, Berkeley, CA 94720 USA. Louisiana Tech Univ, Ruston, LA 71272 USA. Univ Massachusetts, Amherst, MA 01003 USA. Univ Mississippi, University, MS 38677 USA. MIT, Cambridge, MA 02139 USA. Moscow State Univ, Inst Nucl Phys, Moscow 119899, Russia. Nagoya Univ, Nagoya, Aichi 464, Japan. Univ Oregon, Dept Phys, Eugene, OR 97403 USA. Univ Oxford, Oxford OX1 3RH, England. Univ Padua, I-35100 Padua, Italy. Univ Perugia, Sez INFN, I-06100 Perugia, Italy. Ist Nazl Fis Nucl, Sez Pisa, I-56010 Pisa, Italy. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Rutgers State Univ, Serin Phys Labs, Piscataway, NJ 08855 USA. Stanford Linear Accelerator Ctr, Menlo Park, CA 94025 USA. Sogang Univ, Seoul 121742, South Korea. Soongsil Univ, Seoul 156743, South Korea. Univ Tennessee, Knoxville, TN 37996 USA. Tohoku Univ, Bubble Chamber Lab, Sendai, Miyagi 980, Japan. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. Vanderbilt Univ, Stevenson Ctr, Nashville, TN 37235 USA. Univ Washington, Seattle, WA 98105 USA. Univ Wisconsin, Madison, WI 53706 USA. Yale Univ, Gibbs Lab, New Haven, CT 06520 USA. RP Abe, K (reprint author), Aomori Univ, 2-3-1 Kohata, Aomori City 030, Japan. RI de Groot, Nicolo/A-2675-2009; Stahl, Achim/E-8846-2011; de Sangro, Riccardo/J-2901-2012; Cavalli-Sforza, Matteo/H-7102-2015; Frey, Raymond/E-2830-2016; Kamyshkov, Yuri/J-7999-2016; Calcaterra, Alessandro/P-5260-2015 OI Stahl, Achim/0000-0002-8369-7506; de Sangro, Riccardo/0000-0002-3808-5455; Frey, Raymond/0000-0003-0341-2636; Kamyshkov, Yuri/0000-0002-3789-7152; Calcaterra, Alessandro/0000-0003-2670-4826 NR 42 TC 96 Z9 96 U1 0 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1550-7998 J9 PHYS REV D JI Phys. Rev. D PD MAR 1 PY 1999 VL 59 IS 5 AR 052001 DI 10.1103/PhysRevD.59.052001 PG 33 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 173BN UT WOS:000078961200002 ER PT J AU Aznauryan, IG Stepanyan, SG AF Aznauryan, IG Stepanyan, SG TI P-33(1232) resonance contribution to the amplitudes M-1+(3/2),E-1+(3/2),S-1+(3/2) from an analysis of the p(e,e ' p)pi(0) data at Q(2) = 2.8, 3.2, and 4 (GeV/c)(2) within the dispersion relation approach SO PHYSICAL REVIEW D LA English DT Article ID RELATIVIZED QUARK-MODEL; TRANSITION FORM-FACTORS; PION-PHOTOPRODUCTION; GAMMA-N<-->DELTA TRANSITION; DELTA(1232) REGION; DELTA-TRANSITION; MESON-EXCHANGE; NUCLEON; ELECTROPRODUCTION; QUADRUPOLE AB Within the fixed-t dispersion relation approach we have analyzed the TJNAF and DESY data on the exclusive p(e,e'p)pi(0) reaction in order to find the P-33(1232) resonance contribution to the multipole amplitudes M-1+(3/2),E-1+(3/2),S-1+(3/2). As an input for the resonance and nonresonance contributions to these amplitudes the earlier obtained solutions of the integral equations which follow from dispersion relations are used. The obtained values of the ratio E2/M1 for the gamma*N-->P-33(1232) transition are 0.039 +/- 0.029,0.121 +/- 0.032, 0.04 +/- 0.031 for Q(2) = 2.8, 3.2, and 4 (GeV/c)(2), respectively. The comparison with the data at low Q(2) shows that there is no evidence for the presence of the visible perturbative QCD (PQCD) contribution into the transition gamma N-->P-33(1232) at Q(2) = 3-4 GeV2. The ratio (S1+M1+3/2)-M-3/2 for the resonance parts of multipoles is - 0.049 +/- 0.029, -0.099 +/- 0.041, - 0.085 +/- 0.021 for Q(2) = 2.8, 3.2, and 4 (GeV/c)(2), respectively. Our results for the transverse form factor G(T)(Q(2)) of the gamma*N-->P-33(1232) transition are lower than the values obtained from the inclusive data. With increasing Q(2), Q(4)G(T)(Q(2)) decreases, so there is no evidence for the presence of the PQCD contribution here too. [S0556-2821(99)03303-2]. C1 Yerevan Phys Inst, Yerevan 375036, Armenia. Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. RP Aznauryan, IG (reprint author), Yerevan Phys Inst, Alikhanian Bro St 2, Yerevan 375036, Armenia. EM aznaur@jerewanl.yerphi.am; stepanyan@jlab.org NR 53 TC 13 Z9 14 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAR 1 PY 1999 VL 59 IS 5 AR 054009 DI 10.1103/PhysRevD.59.054009 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 173BN UT WOS:000078961200018 ER PT J AU Baer, H Chen, CH Drees, M Paige, F Tata, X AF Baer, H Chen, CH Drees, M Paige, F Tata, X TI Probing minimal supergravity at the CERN LHC for large tan beta SO PHYSICAL REVIEW D LA English DT Article ID FERMILAB TEVATRON COLLIDER; LARGE HADRON COLLIDER; CHARGINO-NEUTRALINO PRODUCTION; SYMMETRY-BREAKING; STANDARD MODEL; SUPERSYMMETRY; UNIFICATION; SIGNALS; MASSES; DECAYS AB For large values of the minimal supergravity model parameter tan beta, the tau lepton and the bottom quark Yukawa couplings become large, leading to reduced masses of tau sleptons and b squarks relative to their first and second generation counterparts, and to enhanced decays of charginos and neutralinos to tau leptons and b quarks. We evaluate the reach of the CERN Large Hadron Collider (LHC) pp collider for supersymmetry in the MSUGRA model parameter space. We find that values of m((g) over tilde) similar to 1500-2000 GeV can be probed with just 10 fb(-1) of integrated luminosity for tan beta values as high as 45, so that MSUGRA cannot escape the scrutiny of LHC experiments by virtue of having a large value of tan beta. We also perform a case study of an MSUGRA model at tan beta = 45 where (Z) over tilde(2)-->tau<(tau)over tilde>(1) and (W) over tilde(1)-->tau(1)nu(tau) with similar to 100% branching fraction. In this case, at least within our simplistic study, we show that a di-tau mass edge, which determines the value of m((Z) over tilde 2) - m((Z) over tilde 1), can still be reconstructed. This information can be used as a starting point for reconstructing SUSY cascade decays on an event-by-event basis, and can provide a strong constraint in determining the underlying model parameters. Finally, we show that for large tan beta, there can be an observable excess of tau leptons, and argue that tau signals might serve to provide new information about the underlying model framework. [S0556-2821(99)04205-8]. C1 Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. Univ Estadual Paulista, IFT, BR-01405900 Sao Paulo, Brazil. Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Hawaii, Dept Phys & Astron, Honolulu, HI 96822 USA. RP Baer, H (reprint author), Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. NR 44 TC 133 Z9 133 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAR 1 PY 1999 VL 59 IS 5 AR 055014 DI 10.1103/PhysRevD.59.055014 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 173BN UT WOS:000078961200056 ER PT J AU Balazs, C Diaz-Cruz, JL He, HJ Tait, T Yuan, CP AF Balazs, C Diaz-Cruz, JL He, HJ Tait, T Yuan, CP TI Probing Higgs bosons with large bottom Yukawa coupling at hadron colliders SO PHYSICAL REVIEW D LA English DT Review ID SUPERSYMMETRIC STANDARD MODEL; ELECTROWEAK SYMMETRY-BREAKING; GROUP FIXED-POINTS; TOPCOLOR-ASSISTED TECHNICOLOR; LARGE TAN-BETA; TOP-QUARK; (P)OVER-BAR-P COLLISIONS; GRAND UNIFICATION; PARTICLE PHYSICS; 3RD GENERATION AB The small mass of the bottom quark, relative to its weak isospin partner, the top quark, makes the bottom an effective probe of new physics in Higgs and top sectors. We study the Higgs boson production associated with bottom quarks, /pp --> -->, at the Fermilab Tevatron and the CERN LHC. We find that strong and model-independent constraints on the size of the phi-b-(b) over bar coupling can be obtained for a wide range of Higgs boson masses. Their implications for the composite Higgs models with strong dynamics associated with the third family quarks (such as the top-quark condensate or top-color models with naturally large bottom Yukawa couplings), and for the supersymmetric models with large tan beta, are analyzed. We conclude that the Tevatron and the LHC can put stringent bounds on these models, if the signal is not found. [S0556-2821(99)00705-5]. C1 Michigan State Univ, E Lansing, MI 48824 USA. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. BUAP, Inst Fis, Puebla 72570, Mexico. Argonne Natl Lab, Argonne, IL 60439 USA. RP Michigan State Univ, E Lansing, MI 48824 USA. NR 124 TC 83 Z9 83 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 MAR 1 PY 1999 VL 59 IS 5 AR 055016 DI 10.1103/PhysRevD.59.055016 PG 21 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 173BN UT WOS:000078961200058 ER PT J AU Balla, J Blotz, A Goeke, K AF Balla, J Blotz, A Goeke, K TI Electric dipole moment of the neutron in the chiral quark soliton model SO PHYSICAL REVIEW D LA English DT Article ID STRONG CP VIOLATION; SKYRME MODEL; QUANTUM CHROMODYNAMICS; CURRENT-ALGEBRA; INSTANTONS; COUPLINGS; NUCLEONS; BREAKING; BARYONS; NAMBU AB Within fhe chiral quark soliton or Nambu-Jona-Lasinio model with a Witten-Veneziano type of U-A(1) symmetry breaking as well as with a finite theta vacuum angle, we calculate the leading term (N(c)(0)m(pi)(2)) in a systematic 1/N-c expansion of the electric dipole moment of the neutron. The consistency requirement that the effects of theta should vanish, if either the anomaly or any quark mass vanishes, is satisfied. The resulting upper limit for theta is theta<2.8x10(-9), which lies close to the upper bound obtained in the literature from other chiral models. [S0556-2821(99)03605-X]. C1 Ruhr Univ Bochum, Inst Theoret Phys 2, D-44780 Bochum, Germany. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Balla, J (reprint author), Ruhr Univ Bochum, Inst Theoret Phys 2, D-44780 Bochum, Germany. EM joba@hadron.tp2.ruhr-uni-bochum.de; blotz@t5.lanl.gov; goeke@hadron.tp2.ruhr-uni-bochum.de NR 35 TC 0 Z9 0 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAR 1 PY 1999 VL 59 IS 5 AR 056005 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 173BN UT WOS:000078961200066 ER PT J AU Bar-Shalom, S Eilam, G Soni, A AF Bar-Shalom, S Eilam, G Soni, A TI R-parity violation, sneutrino mixing phenomena, and CP violation in p(p)over-bar ->(nu)over-tilde -> l(+)l(-)+X SO PHYSICAL REVIEW D LA English DT Article ID PARTON DISTRIBUTIONS; SUPERSYMMETRY; DECAY; CONSTRAINTS; COUPLINGS; RESONANCE; LEPTONS AB The sneutrino resonance reactions p(p)over-bar-->(nu)over-tilde + X-->l(+)l(-) + X, for l = e, mu, tau, in the MSSM without R-parity an considered. We perform a cross-section analysis and show that present limits on some products of Wp Couplings in the sneutrino sector can he significantly improved in future upgraded Fermilab Tevatron runs. Furthermore, we introduce CP-violating and CP-conserving tau-spin asymmetries which are generated already at the tree level in the reaction p(p)over-bar-->(nu)over-tilde + X-->tau(+)tau(-) + X if then is (nu)over-tilde(mu)-(nu)over-tilde(mu) mixing and that vanish in the SM. We find, for example, that for muon-sneutrino masses in the range 150 GeV less than or equal to m((nu))over-tilde>mu) less than or similar to 450 GeV, these spin asymmetries reach similar to 20-30% and similar to 10% for mass splitting between the muon-sneutrino CP-odd and CP-even states at the level of Delta m similar to Gamma and Delta m similar to Gamma/4, respectively, where Gamma is the (nu)over-tilde(mu) width. Both the CP-violating and the CP-conserving spin asymmetries should be detectable in future Tevatron runs even for a heavy sneutrino with a mass less than or similar to 500 GeV. If detected, such asymmetries-being proportional to the mass splitting between the CP-even and CP-odd sneutrino states-may serve as a strong indication for the existence of the sneutrino mixing phenomenon. [S0556-2821(99)04103-X]. C1 Univ Calif Riverside, Dept Phys, Riverside, CA 92521 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Univ Calif Riverside, Dept Phys, Riverside, CA 92521 USA. NR 30 TC 19 Z9 19 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 MAR 1 PY 1999 VL 59 IS 5 AR 055012 DI 10.1103/PhysRevD.59.055012 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 173BN UT WOS:000078961200054 ER PT J AU Burkhardt, H Lowe, J Stephenson, GJ Goldman, T AF Burkhardt, H Lowe, J Stephenson, GJ Goldman, T TI Oscillations of recoil particles against mixed states SO PHYSICAL REVIEW D LA English DT Article ID LAMBDA-OSCILLATIONS; DECAYS AB Some consequences of the oscillations of neutral kaons and neutrinos are discussed, in particular, the possibility of oscillations of particles recoiling against kaons or neutrinos from the production process. We show that there are no stationary oscillations of these recoil particles in any order, and that the apparent long-wavelength oscillations, which might appear to result when an earlier treatment of ours was taken to higher order, are spurious. We show that the recoil particles may show a travelling interference pattern. It may be possible to observe this pattern for Lambda's produced in a reaction, but there seems to be little hope of observing this for the case of neutrinos from muon decay. [S0556-2821(99)00907-8]. C1 Univ New Mexico, Dept Phys, Albuquerque, NM 87131 USA. Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Nottingham, Shell Ctr Math Educ, Nottingham NG7 2RD, England. Univ Birmingham, Dept Phys, Birmingham B15 2TT, W Midlands, England. RP Univ New Mexico, Dept Phys, Albuquerque, NM 87131 USA. NR 20 TC 7 Z9 7 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD MAR 1 PY 1999 VL 59 IS 5 AR 054018 DI 10.1103/PhysRevD.59.054018 PG 7 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 173BN UT WOS:000078961200027 ER PT J AU Dawson, S Reina, L AF Dawson, S Reina, L TI QCD corrections to associated Higgs-boson-heavy-quark production SO PHYSICAL REVIEW D LA English DT Article ID LOOP AB We compute the O(alpha(s)) QCD corrections to the inclusive process e(+)e(-)-->t (t) over bar h. Although the total rate is small, it has a distinctive experimental signature and can potentially be used to measure the top-quark-Higgs-boson Yukawa coupling. The QCD corrections increase the rate by a factor of roughly 1.5 for e(+)e(-)-->t (t) over bar h at root s = 500 GeV and M-h = 100 GeV. At root s = 1 TeV, the corrections are small. [S0556-2821(99)02803-9]. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. RP Dawson, S (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 11 TC 59 Z9 61 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAR 1 PY 1999 VL 59 IS 5 AR 054012 DI 10.1103/PhysRevD.59.054012 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 173BN UT WOS:000078961200021 ER PT J AU Glenn, S Kwon, Y Lyon, AL Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T Artuso, T Dambasuren, E Kopp, S Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Titov, A Viehhauser, G Wang, JC Bartelt, J Csorna, SE McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S Bonvicini, G Cinabro, D Greene, R Perera, LP Zhou, GJ Chan, S Eigen, G Lipeles, E Miller, JS Schmidtler, M Shapiro, A Sun, WM Urheim, J Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Gronberg, J Hill, TS Lange, DJ Morrison, RJ Nelson, HN Nelson, TK Roberts, D Behrens, BH Ford, WT Gritsan, A Krieg, H Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Boisvert, V Cassel, DG Crowcroft, DS Dickson, M von Dombrowski, S Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Galik, RS Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kandaswamy, J Kreinick, DL Lee, T Liu, Y Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Valant-Spaight, B Warburton, A Ward, C Athanas, M Avery, P Jones, CD Lohner, M Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Briere, RA Ershov, A Gao, YS Kim, DYJ Wilson, R Yamamoto, H Browder, TE Li, Y Rodriguez, JL Sahu, SK Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Selen, M Thaler, JJ Edwards, KW Bellerive, A Janicek, R Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Darling, C Davis, R Kotov, S Kravchenko, I Kwak, N Zhou, L Anderson, S Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Hart, T Honscheid, K Kagan, H Kass, R Lee, J Schwarthoff, H Wolf, A Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Bishai, M Chen, S Fast, J Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ AF Glenn, S Kwon, Y Lyon, AL Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T Artuso, T Dambasuren, E Kopp, S Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Titov, A Viehhauser, G Wang, JC Bartelt, J Csorna, SE McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S Bonvicini, G Cinabro, D Greene, R Perera, LP Zhou, GJ Chan, S Eigen, G Lipeles, E Miller, JS Schmidtler, M Shapiro, A Sun, WM Urheim, J Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Gronberg, J Hill, TS Lange, DJ Morrison, RJ Nelson, HN Nelson, TK Roberts, D Behrens, BH Ford, WT Gritsan, A Krieg, H Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Boisvert, V Cassel, DG Crowcroft, DS Dickson, M von Dombrowski, S Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Galik, RS Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kandaswamy, J Kreinick, DL Lee, T Liu, Y Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Valant-Spaight, B Warburton, A Ward, C Athanas, M Avery, P Jones, CD Lohner, M Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Briere, RA Ershov, A Gao, YS Kim, DYJ Wilson, R Yamamoto, H Browder, TE Li, Y Rodriguez, JL Sahu, SK Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Selen, M Thaler, JJ Edwards, KW Bellerive, A Janicek, R Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Darling, C Davis, R Kotov, S Kravchenko, I Kwak, N Zhou, L Anderson, S Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Hart, T Honscheid, K Kagan, H Kass, R Lee, J Schwarthoff, H Wolf, A Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Bishai, M Chen, S Fast, J Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ TI Upsilon dipion transitions at energies near the Upsilon(4S) SO PHYSICAL REVIEW D LA English DT Article ID HADRONIC TRANSITIONS; UPPER LIMIT AB Using a 4.19 fb(-1) data sample collected with the CLEO II detector at the Cornell Electron Storage Ring, we have searched for dipion transitions between pairs of Y resonances at center of mass energies E-c.m. = 10.58 GeV and E-c.m. = 10.52 GeV. We obtain the 90% confidence level upper limits B(Y(4S) Y(2S)pi(+)pi(-))<3.9 x 10(-4) and B(Y(4S)-->Y(1S)pi(+)pi(-))< 1.2 x 10(-4). We also observe the transitions Y(3S)-->Y(1S) pi(+)pi(-), Y(3S)-->Y(2S)pi(+)pi(-), and Y(2S)-->Y(1S)pi(+)pi(-), from which we measure the cross sections for the radiative processes e(+)e(-)-->Y(3S) gamma and e(+)e(-)-->Y(2S) gamma. We obtain sigma(ee-->Y(3S)gamma) =(17.8 +/- 3.0 +/- 1.7) pb and sigma(ee-->Y(2S)gamma) = (15.5 +/- 1.3 +/- 1.4) pb at E-c.m. = 10.58 GeV, and sigma(ee-->Y(3S)gamma) = (27.3 +/- 5.0 +/- 2.6) pb and sigma(ee-->Y(2S)gamma) = (16.3 +/- 1.8 +/- 1.5) pb at E-c.m. = 10.52 GeV, which we compare with theoretical predictions. [S0556-2821(99)02303-6]. C1 Univ Rochester, Rochester, NY 14627 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. So Methodist Univ, Dallas, TX 75275 USA. Syracuse Univ, Syracuse, NY 13244 USA. Vanderbilt Univ, Nashville, TN 37235 USA. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. Wayne State Univ, Detroit, MI 48202 USA. CALTECH, Pasadena, CA 91125 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. Univ Colorado, Boulder, CO 80309 USA. Cornell Univ, Ithaca, NY 14853 USA. Univ Florida, Gainesville, FL 32611 USA. Harvard Univ, Cambridge, MA 02138 USA. Univ Hawaii Manoa, Honolulu, HI 96822 USA. Univ Illinois, Urbana, IL 61801 USA. Carleton Univ, Ottawa, ON K1S 5B6, Canada. Inst Particle Phys, Ottawa, ON, Canada. McGill Univ, Montreal, PQ H3A 2T8, Canada. Ithaca Coll, Ithaca, NY 14850 USA. Univ Kansas, Lawrence, KS 66045 USA. Univ Minnesota, Minneapolis, MN 55455 USA. SUNY Albany, Albany, NY 12222 USA. Ohio State Univ, Columbus, OH 43210 USA. Univ Oklahoma, Norman, OK 73019 USA. Purdue Univ, W Lafayette, IN 47907 USA. Yonsei Univ, Seoul 120749, South Korea. Univ Texas, Austin, TX 78712 USA. RP Glenn, S (reprint author), Univ Rochester, 601 Elmwood Ave, Rochester, NY 14627 USA. RI Warburton, Andreas/N-8028-2013; Briere, Roy/N-7819-2014; OI Warburton, Andreas/0000-0002-2298-7315; Briere, Roy/0000-0001-5229-1039; Poling, Ronald/0000-0001-7305-4702 NR 14 TC 9 Z9 9 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAR 1 PY 1999 VL 59 IS 5 AR 052003 DI 10.1103/PhysRevD.59.052003 PG 8 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 173BN UT WOS:000078961200004 ER PT J AU Grinstein, B Lebed, RF AF Grinstein, B Lebed, RF TI Quark-hadron duality in the 't Hooft model for meson weak decays: Different quark diagram topologies SO PHYSICAL REVIEW D LA English DT Article ID RENORMALIZABLE INTERACTIONS; PERTURBATION-THEORY; RESONANCE PHYSICS; FORM-FACTORS; QCD-DUALITY; HEAVY-QUARK; B-MESONS; CONSTANTS; EXPANSION; LIFETIME AB We compare the effects of different quark diagram topologies on the weak hadronic width of heavy-light mesons in the large N-c limit. We enumerate the various topologies and show that the only one dominant (or even comparable) in powers of N-c to the noninteracting spectator "tree" diagram is the "annihilation" diagram, in which the valence quark-antiquark pair annihilates weakly. We compute the amplitude for this diagram in the 't Hooft model (QCD in 1+1 spacetime dimensions with a large number of colors N-c) at the hadronic level and compare to the Born term partonic level. We find that quark-hadron duality is not well satisfied, even after the application of a smearing procedure to the hadronic result. A number of interesting subtleties absent from the tree diagram case arise in the annihilation diagram case, and are described in detail. [S0556-2821(99)03305-6]. C1 Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. Jefferson Lab, Newport News, VA 23606 USA. RP Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. EM bgrinstein@ucsd.edu; lebed@jlab.org RI Grinstein, Benjamin/H-5777-2015 OI Grinstein, Benjamin/0000-0003-2447-4756 NR 69 TC 12 Z9 12 U1 0 U2 1 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 MAR 1 PY 1999 VL 59 IS 5 AR 054022 DI 10.1103/PhysRevD.59.054022 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 173BN UT WOS:000078961200031 ER PT J AU McGrew, C Becker-Szendy, R Bratton, CB Breault, JL Cady, DR Casper, D Dye, ST Gajewski, W Ganezer, KS Goldhaber, M Haines, TJ Halverson, PG Kielczewska, D Kropp, WR Learned, JG LoSecco, JM Matsuno, S Matthews, J McGrath, G Miller, R Price, LR Reines, F Schultz, J Sinclair, D Sobel, HW Stone, JL Sulak, LR Svoboda, R van der Velde, JC AF McGrew, C Becker-Szendy, R Bratton, CB Breault, JL Cady, DR Casper, D Dye, ST Gajewski, W Ganezer, KS Goldhaber, M Haines, TJ Halverson, PG Kielczewska, D Kropp, WR Learned, JG LoSecco, JM Matsuno, S Matthews, J McGrath, G Miller, R Price, LR Reines, F Schultz, J Sinclair, D Sobel, HW Stone, JL Sulak, LR Svoboda, R van der Velde, JC TI Search for nucleon decay using the IMB-3 detector SO PHYSICAL REVIEW D LA English DT Article ID ATMOSPHERIC NEUTRINOS; FLUX; DEUTERIUM; HYDROGEN AB The IMB-3 experiment was a large water Cherenkov ring imaging detector with a fiducial mass of 3.3 kton. During a 7.6-kton-year exposure (similar to 4.6 x 10(33) nucleon yr) 935 contained events were observed. The observed rate and characteristics are consistent with the expected backgrounds from atmospheric neutrinos. Lower limits on the nucleon lifetime are set for a wide variety of proposed decay modes. [S0556-2821(98)00323-3]. C1 Univ Calif Irvine, Irvine, CA USA. Univ Hawaii Manoa, Honolulu, HI 96822 USA. Cleveland State Univ, Cleveland, OH 44115 USA. Univ Notre Dame, Notre Dame, IN 46556 USA. Boston Univ, Boston, MA 02215 USA. Calif State Univ Dominguez Hills, Carson, CA 90747 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Warsaw Univ, Warsaw, Poland. Univ Michigan, Ann Arbor, MI 48109 USA. Louisiana State Univ, Baton Rouge, LA 70803 USA. RP SUNY Stony Brook, Stony Brook, NY 11794 USA. RI Sobel, Henry/A-4369-2011 NR 26 TC 29 Z9 29 U1 1 U2 1 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 MAR 1 PY 1999 VL 59 IS 5 AR 052004 DI 10.1103/PhysRevD.59.052004 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 173BN UT WOS:000078961200005 ER PT J AU Sides, SW Rikvold, PA Novotny, MA AF Sides, SW Rikvold, PA Novotny, MA TI Kinetic Ising model in an oscillating field: Avrami theory for the hysteretic response and finite-size scaling for the dynamic phase transition SO PHYSICAL REVIEW E LA English DT Article ID MAGNETIC HYSTERESIS; SPIN SYSTEMS; MONTE-CARLO; FORCE MICROSCOPY; TRANSFER-MATRIX; PARTICLES; REVERSAL; FILMS; LOOP; SUSCEPTIBILITY AB Hysteresis is studied for a two-dimensional, spin-1/2, nearest-neighbor. kinetic Ising ferromagnet in a sinusoidally oscillating field, using Monte Carlo simulations and analytical theory. Attention is focused on large systems and moderately strong field amplitudes at a temperature below T-c. In this parameter regime, the magnetization switches through random nucleation and subsequent growth of many droplets of spins aligned with the applied field. Using a time-dependent extension of the Kolmogorov-Johnson-Mehl-Avrami theory of metastable decay, we analyze the statistical properties of the hysteresis-loop area and the correlation between the magnetization and the held. This analysis enables us to accurately predict the results of extensive Monte Carlo simulations. The average loop area exhibits an extremely slow approach to an asymptotic, logarithmic dependence on the product of the amplitude and the field frequency. This may explain the inconsistent exponent estimates reported in previous attempts to fit experimental and numerical data for the low-frequency behavior of this quantity to a power law. At higher frequencies we observe a dynamic phase transition. Applying standard finite-size scaling techniques from the theory of second-order equilibrium phase transitions to this nonequilibrium transition, we obtain estimates for the transition frequency;nd the critical exponents (beta/nu approximate to 0.11, gamma/nu approximate to 1.84, and nu approximate to 1.1). In addition to their significance for the interpretation of recent experiments on switching in ferromagnetic and ferroelectric nanoparticles and thin films, our results provide evidence for the relevance of universality and finite-size scaling to dynamic phase transitions in spatially extended nonstationary systems. [S1063-651X(99)08303-8]. C1 Sandia Natl Labs, Integrated Mat Res Lab, Albuquerque, NM 87185 USA. Florida State Univ, Ctr Mat Res & Technol, Tallahassee, FL 32306 USA. Florida State Univ, Supercomp Computat Res Inst, Tallahassee, FL 32306 USA. Univ Colorado, Colorado Ctr Chaos & Complex, Boulder, CO 80309 USA. Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. RP Sandia Natl Labs, Integrated Mat Res Lab, POB 5800, Albuquerque, NM 87185 USA. EM swsides@sandia.gov; rikvold@scri.fsu.edu; novotny@scri.fsu.edu NR 96 TC 116 Z9 116 U1 2 U2 18 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0045 EI 2470-0053 J9 PHYS REV E JI Phys. Rev. E PD MAR PY 1999 VL 59 IS 3 BP 2710 EP 2729 DI 10.1103/PhysRevE.59.2710 PN A PG 20 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 177WD UT WOS:000079233300040 ER PT J AU Van Siclen, CD AF Van Siclen, CD TI Walker diffusion method for calculation of transport properties of composite materials SO PHYSICAL REVIEW E LA English DT Article ID POROUS-MEDIA; CONDUCTIVITY AB The morphology of a multiphase microstructure greatly influences the macroscopic transport properties of the composite material. These properties are shown to be related to the diffusion coefficient of a random (nonbiased) walker. The proper diffusion rules are found by considering an isomorphic image of the microstructure in which distinct populations of walkers correspond to the phase domains, with the walker density of a population proportional to the transport coefficient of the corresponding domain. To demonstrate the method, it is applied to disordered two-phase percolating composites. [S1063-651X(99)14603-8]. C1 Idaho Natl Lab, Idaho Falls, ID 83415 USA. RP Van Siclen, CD (reprint author), Idaho Natl Lab, Idaho Falls, ID 83415 USA. EM cvs@inel.gov NR 18 TC 17 Z9 17 U1 0 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1539-3755 J9 PHYS REV E JI Phys. Rev. E PD MAR PY 1999 VL 59 IS 3 BP 2804 EP 2807 PN A PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 177WD UT WOS:000079233300050 ER PT J AU Wallace, DC Clements, BE AF Wallace, DC Clements, BE TI Nature of the many-particle potential in the monatomic liquid state: Energetics, kinetics, and stability SO PHYSICAL REVIEW E LA English DT Article ID MOLECULAR-DYNAMICS; SODIUM; TRANSITIONS AB Molecule-dynamics calculations have been used to explore and characterize the many-particle potential underlying the motion of particles in the monatomic liquid state. The potential used accurately represents metallic sodium at the density of the liquid at melt. It is found that the potential surface is composed of a large number of stable nearly harmonic valleys, and that these can be classified as random, symmetric, or crystalline. The random valleys cover by far the major portion of configuration space: they are macroscopically uniform, i.e., they all have the same structural potential and vibrational spectrum: and they all have microscopically irregular anharmonicity. The symmetric valleys lie at potential energies below thr random valleys, but above the bcc crystalline valley. The symmetric valleys are not macroscopically uniform, but show scatter in their structural potentials and their eigenvalue spectra. and the symmetric valleys also have microscopically irregular anharmonicity. The equilibrium states of our system, from zero temperature up to and including the liquid states, fail into three groups, random, symmetric, and crystalline, according to which class of potential valley is mainly visited in the system motion. The random states are well separated from the symmetric and crystalline states, on the graph of mean potential energy versus temperature. The random states lie on a single line over the entire temperature range, and they include the liquid states, demonstrating that the random valleys dominate the statistical mechanics of the liquid. The present results provide detailed confirmation of the liquid-dynamics Hamiltonian previously used in equilibrium and nonequilibrium calculations. Further, the liquid-dynamics prediction of near equality of the log moment of the vibrational spectra, for the liquid and crystal at the same density, is verified here for thr example of sodium. [S1063-651X(99)01903-0]. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Wallace, DC (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, POB 1663, Los Alamos, NM 87545 USA. NR 22 TC 19 Z9 19 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD MAR PY 1999 VL 59 IS 3 BP 2942 EP 2954 DI 10.1103/PhysRevE.59.2942 PN A PG 13 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 177WD UT WOS:000079233300071 ER PT J AU Clements, BE Wallace, DC AF Clements, BE Wallace, DC TI Nature of the many-particle potential in the monatomic liquid state: Radial and angular structure SO PHYSICAL REVIEW E LA English DT Article ID FILMS; NICKEL; IRON AB The atomic configurational order of random, symmetric, and crystalline states of sodium is investigated using molecular-dynamics simulations. Pair distribution functions an calculated for these states. Consistent with the liquid- and random-state energetics, we find that, by cooling, the liquid configurations evolve continuously to random-state structures. For sodium, the random pair distribution function has a split second peak characteristic of many amorphous materials and has the first subpeak exceeding the second subpeak. Experiments have shown this to be the case for amorphous Ni, Co, Cr, Fe, and Mn. A universal pair distribution function is identified for all random structures, as was hypothesized by liquid-dynamics theory. The peak widths of the random pair distribution function are considerably broader, even at very low temperatures, than those of the bcc and symmetric structures. No universal pair distribution function exists for symmetric structures. For low-temperature random, symmetric, and crystalline structures we determine average Voronoi coordination numbers, angular distributions between neighboring atomic triplets, and the number of Voronoi edges per face. Without exception the random and symmetric structures show very different trends for each of these properties. The universal nature of the random structures is also apparent in each property exhibited in the Voronoi polyhedra, unlike for the symmetric structures. Angles between neighboring Voronoi triplets common to random close-packing structures are favored by the random structures whereas those hinting at microcrystalline order are found for the symmetric structures. The distribution of Voronoi coordination numbers for both random and symmetric structures are peaked at 14 neighbors, but while the symmetric structures are essentially all 14, the random structures have nearly as many 13 and 15 neighbor polyhedra. The number of edges per face also shows a stark difference between the random and symmetric structures, the number is broadly distributed about the peak value 5 for the random structures, but contains many more four- and six-edged faces (and very few five-edged faces) for the symmetric structures. [S1063-651X(99)02203-5]. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Clements, BE (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, POB 1663, Los Alamos, NM 87545 USA. NR 16 TC 15 Z9 15 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD MAR PY 1999 VL 59 IS 3 BP 2955 EP 2965 DI 10.1103/PhysRevE.59.2955 PN A PG 11 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 177WD UT WOS:000079233300072 ER PT J AU Moss, WC Young, DA Harte, JA Levatin, JL Rozsnyai, BF Zimmerman, GB Zimmerman, IH AF Moss, WC Young, DA Harte, JA Levatin, JL Rozsnyai, BF Zimmerman, GB Zimmerman, IH TI Computed optical emissions from a sonoluminescing bubble SO PHYSICAL REVIEW E LA English DT Article ID SINGLE; AIR AB A sonoluminescing bubble has been modeled as a thermally conducting, partially ionized plasma. The model is mon complete than previous models, due to the inclusion of both plasma and normal molecular thermal conduction, vapor pressure, surface tension, the mixing of gas and water vapor in the bubble, and opacities. The model accounts for most of the observed experimental trends. including (i) the asymmetric pulse shape; (ii) the temperature and driving pressure dependence of the pulse width and intensity; and (iii) spectral shapes, in particular, the 300-nm peak in the spectrum of xenon sonoluminescence, which to our knowledge has not been explained by any previous model; and (iv) a hydrodynamic explanation of why water is the "friendliest" liquid in which sonoluminescence occurs. The agreement between the calculations and the data, as well as the model's predictions of almost every experimental trend, suggest strongly that the spectral and temporal properties of the emissions of a sonoluminescing bubble are due to adiabatic- or shock-initiated thermal emission from a cool dense plasma. [S1063-651X(99)07503-0]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Moss, WC (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94550 USA. EM wmoss@llnl.gov NR 31 TC 103 Z9 107 U1 1 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD MAR PY 1999 VL 59 IS 3 BP 2986 EP 2992 DI 10.1103/PhysRevE.59.2986 PN A PG 7 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 177WD UT WOS:000079233300076 ER PT J AU Fernandez-Perea, R Bermejo, FJ Martinez, JL Enciso, E Verkerk, P AF Fernandez-Perea, R Bermejo, FJ Martinez, JL Enciso, E Verkerk, P TI Collective dynamics on a crystal composed by disparate-mass particles: Li22Pb5 SO PHYSICAL REVIEW E LA English DT Article ID INELASTIC NEUTRON-SCATTERING; FAST SOUND; LIQUID LI4PB; MIXTURES; LITHIUM; MODEL AB The lattice dynamics of crystalline Li22Pb5 is studied by means of computer simulations. The calculated spectrum shows several bands corresponding to modes in which only the light atoms execute motions. The spectrum of acoustic modes is found to be well separated from the high-frequency bands and is in all cases confined to frequencies below 4 meV. The results are shown to provide a clue for the understanding of the origin of the strong anomalous dispersion features found in the melt by experiment [Phys. Rev. Lett. 80, 2141 (1998)] and molecular dynamics simulations [Phys. Rev. E 58, 4568 (1998)]. [S1063-651X(99)10003-5]. C1 CSIC, E-28006 Madrid, Spain. Delft Univ Technol, Interfac Reactor Inst, NL-2629 JB Delft, Netherlands. RP Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Martinez, Jose/B-5371-2013; Fernandez-Perea, Ricardo/E-9118-2016 OI Martinez, Jose/0000-0001-9046-8237; Fernandez-Perea, Ricardo/0000-0002-4011-2344 NR 33 TC 9 Z9 9 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0045 EI 2470-0053 J9 PHYS REV E JI Phys. Rev. E PD MAR PY 1999 VL 59 IS 3 BP 3212 EP 3222 DI 10.1103/PhysRevE.59.3212 PN B PG 11 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 177WF UT WOS:000079233500021 ER PT J AU Mason, PC Gaulin, BD Epand, RM Wignall, GD Lin, JS AF Mason, PC Gaulin, BD Epand, RM Wignall, GD Lin, JS TI Small angle neutron scattering and calorimetric studies of large unilamellar vesicles of the phospholipid dipalmitoylphosphatidylcholine SO PHYSICAL REVIEW E LA English DT Article ID RAPID EXTRUSION PROCEDURE; RED-BLOOD-CELLS; RIPPLE PHASE; PHOSPHATIDYLCHOLINE VESICLES; OSMOTIC-STRESS; BILAYERS; TRANSITION; CURVATURE; DIMYRISTOYLPHOSPHATIDYLCHOLINE; DISTRIBUTIONS AB High-resolution differential scanning calorimetry (DSC) and small angle neutron scattering (SANS) experiments have been conducted on large unilamellar vesicles (LUV's) of the phospholipid dipalmitoylphosphatidylcholine (DPPC) in excess water. The DSC results indicate a phase transition at temperatures corresponding to the gel (L-beta') to ripple (P-beta') phase transition seen in multilamellar vesicles of DPPC while the SANS experiments provide direct evidence for the formation of the P-beta' phase in these systems. In addition, it is shown that SANS is an effective technique for extracting structural parameters such as vesicle radius and thickness in LUV model membrane systems. [S1063-651X(99)02103-0]. C1 McMaster Univ, Dept Phys & Astron, Hamilton, ON L8S 4M1, Canada. McMaster Univ, Dept Biochem, Hamilton, ON L8N 3Z5, Canada. Oak Ridge Natl Lab, Ctr Small Angle Scattering Res, Oak Ridge, TN 37831 USA. RP Mason, PC (reprint author), McMaster Univ, Dept Phys & Astron, Hamilton, ON L8S 4M1, Canada. RI Piper, Walter/B-7908-2009; OI Wignall, George/0000-0002-3876-3244 NR 43 TC 33 Z9 33 U1 1 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD MAR PY 1999 VL 59 IS 3 BP 3361 EP 3367 DI 10.1103/PhysRevE.59.3361 PN B PG 7 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 177WF UT WOS:000079233500036 ER PT J AU Fye, RM Benham, CJ AF Fye, RM Benham, CJ TI Exact method for numerically analyzing a model of local denaturation in superhelically stressed DNA SO PHYSICAL REVIEW E LA English DT Article ID CLOSED CIRCULAR DNA; SUPERCOILED DNA; ESCHERICHIA-COLI; CONFORMATIONAL TRANSITIONS; DUPLEX DESTABILIZATION; THERMAL-DENATURATION; STABILITY; METHYLATION; REGIONS; HELIX AB Local denaturation, the separation at specific sites of the two strands comprising the DNA double helix, is one of the most fundamental processes in biology, required to allow the base sequence to be read both in DNA transcription and in replication. In living organisms this process can be mediated by enzymes which regulate the amount of superhelical stress imposed on the DNA. We present a numerically exact technique for analyzing a model of denaturation in superhelically stressed DNA. This approach is capable of predicting the locations and extents of transition in circular superhelical DNA molecules of kilobase lengths and specified base pair sequences. It can also be used for closed loops of DNA which are typically found in vivo to be kilobases long. The analytic method consists of an integration over the DNA twist degrees of freedom followed by the introduction of auxiliary variables to decouple the remaining degrees of freedom, which allows the use of the transfer matrix method. The algorithm implementing our technique requires O(N-2) operations and O(N) memory to analyze a DNA domain containing N base pairs. However, to analyze kilobase length DNA molecules it must be implemented in high precision floating point arithmetic. An accelerated algorithm is constructed by imposing an upper bound M on the number of base pairs that can simultaneously denature in a state. This accelerated algorithm requires O(MN) operations, and has an analytically bounded error. Sample calculations show that it achieves high accuracy (greater than 15 decimal digits) with relatively small values of dl (M<0.05N) for kilobase length molecules under physiologically relevant conditions. Calculations are performed on the superhelical pBR322 DNA sequence to test the accuracy of the method. With no free parameters in the model, the locations and extents of local denaturation predicted by this analysis are in quantitatively precise agreement with in vitro experimental measurements. Calculations performed on the fructose-1,6-bisphosphatase gene sequence from yeast show that this approach can also accurately treat in vivo denaturation. [S1063-651X(99)06003-1]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Mt Sinai Sch Med, Dept Biomath Sci, New York, NY 10029 USA. RP Benham, CJ (reprint author), Sandia Natl Labs, POB 5800,MS-1111, Albuquerque, NM 87185 USA. RI Benham, Craig/G-1512-2013 NR 46 TC 52 Z9 53 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD MAR PY 1999 VL 59 IS 3 BP 3408 EP 3426 DI 10.1103/PhysRevE.59.3408 PN B PG 19 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 177WF UT WOS:000079233500042 ER PT J AU Alexiou, S Sauvan, P Poquerusse, A Leboucher-Dalimier, E Lee, RW AF Alexiou, S Sauvan, P Poquerusse, A Leboucher-Dalimier, E Lee, RW TI Accuracy of simplified methods for ion dynamics in Stark profile calculations SO PHYSICAL REVIEW E LA English DT Article ID BROADENING THEORY; DENSE-PLASMAS; LINE-SHAPE; ALPHA; MODEL; HOT AB To assess the accuracy of simplified methods for the treatment of ion dynamics in Stark-broadening theory, we have compared two such methods, the relaxation theory and model microfield method, against benchmark calculations fur the CVI H-alpha line. It is shown that both methods show poor agreement at low densities. [S1063-651X(99)12702-8]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Paris 06, Ecole Polytech, CEA,Lab Utilisat Lasers Intenses,UM 7605, CNRS, F-75252 Paris 05, France. Ecole Polytech, F-91128 Palaiseau, France. RP Lee, RW (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-399, Livermore, CA 94550 USA. RI Sauvan, Patrick/M-3778-2014 OI Sauvan, Patrick/0000-0002-9128-8817 NR 25 TC 8 Z9 8 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD MAR PY 1999 VL 59 IS 3 BP 3499 EP 3502 DI 10.1103/PhysRevE.59.3499 PN B PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 177WF UT WOS:000079233500050 ER PT J AU Burov, A Danilov, V Shiltsev, V AF Burov, A Danilov, V Shiltsev, V TI Transverse beam stability with an "electron lens" SO PHYSICAL REVIEW E LA English DT Article ID MODE-COUPLING INSTABILITY AB This article is devoted to stability analysis of the antiproton beam interacting with an electron beam in an "electron lens" setup for beam-beam compensation in the Tevatron collider. Electron space charge fords cause transverse ''head-tail'' coupling within antiproton bunch which may lead to a transverse mode coupling instability (TMCI). We present a theory, analytical studies, and numerical simulations of this effect. An estimate of threshold longitudinal magnetic field necessary to avoid the instability is given. Dependence of the threshold on electron and antiproton beam parameters is studied. [S1063-651X(99)10203-4]. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Burov, A (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 15 TC 7 Z9 7 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD MAR PY 1999 VL 59 IS 3 BP 3605 EP 3613 DI 10.1103/PhysRevE.59.3605 PN B PG 9 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 177WF UT WOS:000079233500061 ER PT J AU Johnson, JD AF Johnson, JD TI Bound and estimate for the maximum compression of single shocks SO PHYSICAL REVIEW E LA English DT Article AB We derive that the compression for any single shock has an upper bound of 7. This is in the case of shocking from any initial stare except gaseous densities with temperatures such that a significant fraction of the electrons are bound. For shocks in condensed material initially near ambient, we present a simple analytic estimate for the maximum compression as a function of rho(0) (initial density), A (atomic weight), Z (atomic number), and Delta E (the sum of cohesion, dissociation, and total ionization energies). [S1063-651X(99)07803-4]. C1 Univ Calif Los Alamos Natl Lab, T Div, Los Alamos, NM 87545 USA. RP Johnson, JD (reprint author), Univ Calif Los Alamos Natl Lab, T Div, POB 1663, Los Alamos, NM 87545 USA. NR 7 TC 13 Z9 16 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD MAR PY 1999 VL 59 IS 3 BP 3727 EP 3728 DI 10.1103/PhysRevE.59.3727 PN B PG 2 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 177WF UT WOS:000079233500081 ER PT J AU Benkadda, S Kassibrakis, S White, R Zaslavsky, GM AF Benkadda, S Kassibrakis, S White, R Zaslavsky, GM TI Reply to "Comment on 'Self-similarity and transport in the standard map'" SO PHYSICAL REVIEW E LA English DT Letter ID SYSTEMS AB In the Comment by Zumofen and Klafter (ZK) (Phys. Rev. E, preceding paper) the authors, comparing their results to those in a publication of ours [Benkadda, Kassibrakis, White, and Zaslavsky (BKWZ)] [Phys. Rev. E 55, 4909 (1997)], state that "disagreement is regarded as resulting from conceptual differences in the approaches rather than from numerical inaccuracies." The papers discuss superdiffusion phenomena for the standard map. In fact, we will show here that the numerical results of ZK contradict neither the numerical results given in BKWZ nor the theory referenced there. At the same time we will indicate precisely why the theory used in ZK has restricted applicability and is not universal. We also provide additional analytical and numerical results in support of our conclusions. [S1063-651X(99)06803-8]. C1 Univ Aix Marseille 1, Ctr St Jerome, Equipe Turbulence Plasma, CNRS,LPIIM, F-13397 Marseille, France. Princeton Univ, Plasma Phys Lab, Princeton, NJ 08543 USA. NYU, Courant Inst Math Sci, New York, NY 10012 USA. NYU, Dept Phys, New York, NY 10003 USA. RP Univ Aix Marseille 1, Ctr St Jerome, Equipe Turbulence Plasma, CNRS,LPIIM, F-13397 Marseille, France. NR 15 TC 19 Z9 19 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0045 EI 2470-0053 J9 PHYS REV E JI Phys. Rev. E PD MAR PY 1999 VL 59 IS 3 BP 3761 EP 3764 DI 10.1103/PhysRevE.59.3761 PN B PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 177WF UT WOS:000079233500090 ER PT J AU Fukuda, Y Hayakawa, T Ichihara, E Inoue, K Ishihara, K Ishino, H Itow, Y Kajita, T Kameda, J Kasuga, S Kobayashi, K Kobayashi, Y Koshio, Y Miura, M Nakahata, M Nakayama, S Okada, A Okumura, K Sakurai, N Shiozawa, M Suzuki, Y Takeuchi, Y Totsuka, Y Yamada, S Earl, M Habig, A Kearns, E Messier, MD Scholberg, K Stone, JL Sulak, LR Walter, CW Goldhaber, M Barszczak, T Casper, D Gajewski, W Halverson, PG Hsu, J Kropp, WR Price, LR Reines, F Smy, M Sobel, HW Vagins, MR Ganezer, KS Keig, WE Ellsworth, RW Tasaka, S Flanagan, JW Kibayashi, A Learned, JG Matsuno, S Stenger, VJ Takemori, D Ishii, T Kanzaki, J Kobayashi, T Mine, S Nakamura, K Nishikawa, K Oyama, Y Sakai, A Sakuda, M Sasaki, O Echigo, S Kohama, M Suzuki, AT Haines, TJ Blaufuss, E Kim, BK Sanford, R Svoboda, R Chen, ML Conner, Z Goodman, JA Sullivan, GW Hill, J Jung, CK Martens, K Mauger, C McGrew, C Sharkey, E Viren, B Yanagisawa, C Doki, W Miyano, K Okazawa, H Saji, C Takahata, M Nagashima, Y Takita, M Yamaguchi, T Yoshida, M Kim, SB Etoh, M Fujita, K Hasegawa, A Hasagawa, T Hatakeyama, S Iwamoto, T Koga, M Maruyama, T Ogawa, H Shirai, J Suzuki, A Tsushima, F Koshiba, M Iwamoto, T Koga, M Maruyama, T Ogawa, H Shirai, J Suzuki, A Tsushima, F Koshiba, M Nemoto, M Nishijima, K Futagami, T Hayato, Y Kanaya, Y Kaneyuki, K Watanabe, Y Kielczewska, D Doyle, RA George, JS Stachyra, AL Wai, LL Wilkes, RJ Young, KK AF Fukuda, Y Hayakawa, T Ichihara, E Inoue, K Ishihara, K Ishino, H Itow, Y Kajita, T Kameda, J Kasuga, S Kobayashi, K Kobayashi, Y Koshio, Y Miura, M Nakahata, M Nakayama, S Okada, A Okumura, K Sakurai, N Shiozawa, M Suzuki, Y Takeuchi, Y Totsuka, Y Yamada, S Earl, M Habig, A Kearns, E Messier, MD Scholberg, K Stone, JL Sulak, LR Walter, CW Goldhaber, M Barszczak, T Casper, D Gajewski, W Halverson, PG Hsu, J Kropp, WR Price, LR Reines, F Smy, M Sobel, HW Vagins, MR Ganezer, KS Keig, WE Ellsworth, RW Tasaka, S Flanagan, JW Kibayashi, A Learned, JG Matsuno, S Stenger, VJ Takemori, D Ishii, T Kanzaki, J Kobayashi, T Mine, S Nakamura, K Nishikawa, K Oyama, Y Sakai, A Sakuda, M Sasaki, O Echigo, S Kohama, M Suzuki, AT Haines, TJ Blaufuss, E Kim, BK Sanford, R Svoboda, R Chen, ML Conner, Z Goodman, JA Sullivan, GW Hill, J Jung, CK Martens, K Mauger, C McGrew, C Sharkey, E Viren, B Yanagisawa, C Doki, W Miyano, K Okazawa, H Saji, C Takahata, M Nagashima, Y Takita, M Yamaguchi, T Yoshida, M Kim, SB Etoh, M Fujita, K Hasegawa, A Hasagawa, T Hatakeyama, S Iwamoto, T Koga, M Maruyama, T Ogawa, H Shirai, J Suzuki, A Tsushima, F Koshiba, M Iwamoto, T Koga, M Maruyama, T Ogawa, H Shirai, J Suzuki, A Tsushima, F Koshiba, M Nemoto, M Nishijima, K Futagami, T Hayato, Y Kanaya, Y Kaneyuki, K Watanabe, Y Kielczewska, D Doyle, RA George, JS Stachyra, AL Wai, LL Wilkes, RJ Young, KK CA Super-Kamiokande Collaboration TI Constraints on neutrino oscillation parameters from the measurement of day-night solar neutrino fluxes at Super-Kamiokande SO PHYSICAL REVIEW LETTERS LA English DT Article ID MODEL; SUN; MATTER AB A search for day-night variations in the solar neutrino flux resulting from neutrino oscillations has been carried out using the 504 day sample of solar neutrino data obtained at Super-Kamiokande, The absence of a significant day-night variation has set an absolute: Bur independent exclusion region in the two neutrino oscillation parameter space. [S0031-9007(99)08599-3]. C1 Univ Tokyo, Inst Cosm Ray Res, Tokyo 1888502, Japan. Boston Univ, Dept Phys, Boston, MA 02215 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA. Calif State Univ Dominguez Hills, Dept Phys, Carson, CA 90747 USA. George Mason Univ, Dept Phys, Fairfax, VA 22030 USA. Gifu Univ, Dept Phys, Gifu 5011193, Japan. Univ Hawaii, Dept Phys & Astron, Honolulu, HI 96822 USA. High Energy Accelerator Res Org KEK, Inst Particle & Nucl Studies, Ibaraki, Osaka 3050801, Japan. Kobe Univ, Dept Phys, Kobe, Hyogo 6578501, Japan. Univ Calif Los Alamos Natl Lab, Dept Phys, Los Alamos, NM 87544 USA. Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. Niigata Univ, Dept Phys, Niigata 9502181, Japan. Osaka Univ, Dept Phys, Osaka 5600043, Japan. Seoul Natl Univ, Dept Phys, Seoul 151742, South Korea. Tohoku Univ, Dept Phys, Sendai, Miyagi 9808578, Japan. Univ Tokyo, Tokyo 1130033, Japan. Tokai Univ, Dept Phys, Kanagawa 2591292, Japan. Tokyo Inst Technol, Dept Phys, Meguro Ku, Tokyo 1528551, Japan. Univ Warsaw, Inst Expt Phys, PL-00681 Warsaw, Poland. Univ Washington, Dept Phys, Seattle, WA 98195 USA. RP Fukuda, Y (reprint author), Univ Tokyo, Inst Cosm Ray Res, Tokyo 1888502, Japan. RI Takeuchi, Yasuo/A-4310-2011; Kibayashi, Atsuko/K-7327-2015; Nakamura, Kenzo/F-7174-2010; Sobel, Henry/A-4369-2011; Suzuki, Yoichiro/F-7542-2010; Martens, Kai/A-4323-2011; Wilkes, R.Jeffrey/E-6011-2013; Kim, Soo-Bong/B-7061-2014; Sakurai, Nobuyuki/M-5009-2014; Ishino, Hirokazu/C-1994-2015; Koshio, Yusuke/C-2847-2015 OI Sakurai, Nobuyuki/0000-0002-1002-217X; Ishino, Hirokazu/0000-0002-8623-4080; Koshio, Yusuke/0000-0003-0437-8505 NR 22 TC 389 Z9 391 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 MAR 1 PY 1999 VL 82 IS 9 BP 1810 EP 1814 DI 10.1103/PhysRevLett.82.1810 PG 5 WC Physics, Multidisciplinary SC Physics GA 171RC UT WOS:000078877000003 ER PT J AU Berry, LA Jaeger, EF Batchelor, DB AF Berry, LA Jaeger, EF Batchelor, DB TI Wave-induced momentum transport and flow drive in tokamak plasmas SO PHYSICAL REVIEW LETTERS LA English DT Article ID SHEAR SUPPRESSION; EDGE TURBULENCE AB Wave-induced flows are calculated from high-resolution electromagnetic field calculations with either a compressible Reynolds stress or a second-order kinetic pressure model for the radio frequency forces. Results show that electron Landau damping and magnetic pumping, by themselves, do not lead to significant poloidal flow as long as there is Little net input of momentum by the wave. But ion-cyclotron damping of either fast magnetosonic waves or ion-Bernstein waves can drive significant poloidal flows at power levels typical of plasma-heating experiments. [S0031-9007(99)08584-1]. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Berry, LA (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 12 TC 56 Z9 56 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 MAR 1 PY 1999 VL 82 IS 9 BP 1871 EP 1874 DI 10.1103/PhysRevLett.82.1871 PG 4 WC Physics, Multidisciplinary SC Physics GA 171RC UT WOS:000078877000018 ER PT J AU Reboredo, FA Pantelides, ST AF Reboredo, FA Pantelides, ST TI Novel defect complexes and their role in the p-type doping of GaN SO PHYSICAL REVIEW LETTERS LA English DT Article ID LOCAL VIBRATIONAL-MODES; GALLIUM NITRIDE; NATIVE DEFECTS; HYDROGEN; DIODES AB Hydrogen is known to play a key role in p-type doping of GaN. It is believed that H passivates Mg dopants and then is removed by annealing. We present first principles calculations in terms of which we show that the doping process is significantly more complex. Several substitutional-interstitial complexes form and can bind H, with vibrational frequencies that correlate well with hitherto unidentified observed lines. We predict that these defects, which limit doping efficiency, can be eliminated by annealing in an atmosphere of H and N prior to the final anneal that removes H. [S0031-9007(99)08520-8]. C1 Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Reboredo, FA (reprint author), Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. RI Reboredo, Fernando/B-8391-2009 NR 18 TC 58 Z9 59 U1 3 U2 18 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAR 1 PY 1999 VL 82 IS 9 BP 1887 EP 1890 DI 10.1103/PhysRevLett.82.1887 PG 4 WC Physics, Multidisciplinary SC Physics GA 171RC UT WOS:000078877000022 ER PT J AU Suchorski, Y Beben, J James, EW Evans, JW Imbihl, R AF Suchorski, Y Beben, J James, EW Evans, JW Imbihl, R TI Fluctuation-induced transitions in a bistable surface reaction: Catalytic CO oxidation on a Pt field emitter tip SO PHYSICAL REVIEW LETTERS LA English DT Article ID REACTION MODEL; EQUILIBRIUM; DIFFUSION; REACTANTS; KINETICS; PHASE AB Fluctuations which arise in catalytic CO oxidation on a Pt field emitter tip have been studied with field electron microscopy as the imaging method. Fluctuation-driven transitions between the active and the inactive branch of the reaction are found to occur sufficiently close to the bifurcation point, terminating the bistable range. The experimental results are modeled with Monte Carlo simulations of a lattice-gas reaction model incorporating rapid CO diffusion. C1 Univ Hannover, Inst Phys Chem & Elektrochem, D-30167 Hannover, Germany. Univ Wroclaw, Inst Phys Expt, PL-50204 Wroclaw, Poland. Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Math, Ames, IA 50011 USA. RP Suchorski, Y (reprint author), Univ Hannover, Inst Phys Chem & Elektrochem, Callinstr 3-3A, D-30167 Hannover, Germany. NR 26 TC 99 Z9 102 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 MAR 1 PY 1999 VL 82 IS 9 BP 1907 EP 1910 DI 10.1103/PhysRevLett.82.1907 PG 4 WC Physics, Multidisciplinary SC Physics GA 171RC UT WOS:000078877000027 ER PT J AU Choi, HJ Kawakami, RK Escorcia-Aparicio, EJ Qiu, ZQ Pearson, J Jiang, JS Li, DQ Bader, SD AF Choi, HJ Kawakami, RK Escorcia-Aparicio, EJ Qiu, ZQ Pearson, J Jiang, JS Li, DQ Bader, SD TI Curie temperature enhancement and induced Pd magnetic moments for ultrathin Fe films grown on stepped Pd(001) SO PHYSICAL REVIEW LETTERS LA English DT Article ID SURFACE-STATES; COBALT FILMS; ANISOTROPY AB Fe films grown in ultrahigh vacuum onto a curved Pd(001) substrate with a continuous gradient in atomic step density were studied in situ via the surface magneto-optic Kerr effect (SMOKE). The steps induce an in-plane, uniaxial magnetic anisotropy with the easy axis perpendicular to the step edges, and whose strength scales linearly with step density. The Curie temperature of 1-2 monolayers of Fe is enhanced by the steps relative to that on a flat substrate. The enhancement is attributed to a step-induced Pd moment at step edges, as inferred from the enhancement of the SMOKE signal with step density. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Choi, HJ (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Bader, Samuel/A-2995-2013; Qiu, Zi Qiang/O-4421-2016 OI Qiu, Zi Qiang/0000-0003-0680-0714 NR 17 TC 49 Z9 49 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 MAR 1 PY 1999 VL 82 IS 9 BP 1947 EP 1950 DI 10.1103/PhysRevLett.82.1947 PG 4 WC Physics, Multidisciplinary SC Physics GA 171RC UT WOS:000078877000037 ER PT J AU Rohlfing, M Louie, SG AF Rohlfing, M Louie, SG TI Optical excitations in conjugated polymers SO PHYSICAL REVIEW LETTERS LA English DT Article ID ELECTRON CORRELATION; TRANS-POLYACETYLENE; BAND-GAPS; SEMICONDUCTORS; INSULATORS; OLIGOMERS; SPECTRUM AB We investigate optical absorption spectra and excitons in conjugated polymers from first principles. This is done by calculating the one-particle and the two-particle Green's function, including relevant many-body effects, and evaluating quasiparticle and optical excitations. Trans-polyacetylene and poly phenylene-vinylene are studied as prototype long chain polymers. The electron-hole interaction gives rise to large exciton binding energies (similar to 1 eV) and dramatically alters the optical spectra. The calculated exciton wave functions are very extended in real space. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Rohlfing, M (reprint author), Univ Munster, Inst Theoret Phys 2, D-48149 Munster, Germany. NR 26 TC 220 Z9 221 U1 1 U2 20 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 MAR 1 PY 1999 VL 82 IS 9 BP 1959 EP 1962 DI 10.1103/PhysRevLett.82.1959 PG 4 WC Physics, Multidisciplinary SC Physics GA 171RC UT WOS:000078877000040 ER PT J AU Soukoulis, CM Busch, K Kafesaki, M Economou, EN AF Soukoulis, CM Busch, K Kafesaki, M Economou, EN TI Comment on "Energy velocity of diffusing waves in strongly scattering media" SO PHYSICAL REVIEW LETTERS LA English DT Article ID TRANSPORT-PROPERTIES C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames, IA 50011 USA. Univ Toronto, Dept Phys, Toronto, ON M5S LA7, Canada. FORTH, Res Ctr Crete, Heraklion 71110, Greece. Dept Phys, Heraklion 71110, Greece. RP Soukoulis, CM (reprint author), Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. RI Kafesaki, Maria/E-6843-2012; Economou, Eleftherios /E-6374-2010; Soukoulis, Costas/A-5295-2008 OI Kafesaki, Maria/0000-0002-9524-2576; NR 10 TC 7 Z9 7 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 MAR 1 PY 1999 VL 82 IS 9 BP 2000 EP 2000 DI 10.1103/PhysRevLett.82.2000 PG 1 WC Physics, Multidisciplinary SC Physics GA 171RC UT WOS:000078877000051 ER PT J AU Davidson, RC Qin, H Wang, TSF AF Davidson, RC Qin, H Wang, TSF TI Vlasov-Maxwell description of electron-ion two-stream instability in high-intensity linacs and storage rings SO PHYSICS LETTERS A LA English DT Article ID BEAM AB The Vlasov-Maxwell equations are used to investigate properties of the electron-ion two-stream instability for a continuous, high-intensity ion beam propagating in the z-direction with directed axial velocity V-b = beta(b)c through a background population of (stationary) electrons. The analysis is carried out for arbitrary beam intensity, consistent with transverse confinement of the beam particles, and arbitrary fractional charge neutralization by the background electrons. Detailed stability properties are calculated over a wide range of system parameters for dipole perturbations with azimuthal mode number l = i. The instability growth rate Im omega is found to increase with increasing normalized beam intensity (<(omega)over cap>(2)(pb)/omega(beta b)(O2)), increasing fractional charge neutralization (f = (n) over cap(e)/Z(b)(n) over cap(b)), and decreasing proximity of the conducting wall (r(b)/r(w)). (C) 1999 Elsevier Science B.V. C1 Princeton Univ, Plasma Phys Lab, Princeton, NJ 08543 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Davidson, RC (reprint author), Princeton Univ, Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 26 TC 22 Z9 22 U1 0 U2 2 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 MAR 1 PY 1999 VL 252 IS 5 BP 213 EP 221 DI 10.1016/S0375-9601(99)00002-X PG 9 WC Physics, Multidisciplinary SC Physics GA 172BK UT WOS:000078901500001 ER PT J AU Alde, D Binon, F Boutemeur, M Bricman, C Donskov, SV Gouanere, M Inaba, S Inyakin, AV Kachanov, VA Khaustov, GV Knapp, EA Kondashov, AA Lednev, AA Lishin, VA Peigneux, JP Poulet, M Prokoshkin, YD Sadovsky, SA Samoylenko, VD Shagin, PM Singovsky, AV Stroot, JP Sugonyaev, VP Takamatsu, K Tsuru, T AF Alde, D Binon, F Boutemeur, M Bricman, C Donskov, SV Gouanere, M Inaba, S Inyakin, AV Kachanov, VA Khaustov, GV Knapp, EA Kondashov, AA Lednev, AA Lishin, VA Peigneux, JP Poulet, M Prokoshkin, YD Sadovsky, SA Samoylenko, VD Shagin, PM Singovsky, AV Stroot, JP Sugonyaev, VP Takamatsu, K Tsuru, T CA GAMS Collaboration TI Investigation of the pi(0)pi(0) system at a primary momentum of 100 GeV/c by using the GAMS-4000 spectrometer SO PHYSICS OF ATOMIC NUCLEI LA English DT Article ID AMPLITUDE; CHANNEL; REGION; WAVE; PI AB The pi(0)pi(0) system produced in charge-exchange pi(-)p interactions at a primary momentum of 100 GeV/c has been studied. The data employed come from the experiment that was performed at the CERN SPS accelerator and which recorded photons from pi(0) decays with the aid of the hodoscopic multiphoton GAMS-4000 spectrometer. A partial-wave analysis of the pi(0)pi(0) system in the mass interval between 0.8 and 3 GeV has been performed with allowance for the S, D, G, and J waves. The S wave has a rather complicated structure, displaying a series of four bumps separated by three dips at about 1, 1.5, and 2 GeV. This suggests the existence of several scalar resonances. The higher waves show clear peaks corresponding to the f(2)(1270), f(4)(2050), and f(6)(2510) mesons, which are produced predominantly via one-pion exchange. The parameters of these mesons and their production cross sections have been determined. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Inst High Energy Phys, Protvino 142284, Moscow Oblast, Russia. Inst Interuniv Sci Nucl, Brussels, Belgium. Lab Annecy Le Vieux Phys Particules, F-74941 Annecy Le Vieux, France. Natl Lab High Energy Phys, KEK, Tsukuba, Ibaraki 305, Japan. CERN, CH-1211 Geneva 23, Switzerland. Free Univ Brussels, B-1050 Brussels, Belgium. Miyazaki Univ, Miyazaki 8892192, Japan. RP Alde, D (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 29 TC 0 Z9 0 U1 0 U2 0 PU MAIK NAUKA/INTERPERIODICA PUBL PI WOODBURY PA C/O AMERICAN INST PHYSICS, 500 SUNNYSIDE BLVD, MEMBER SUBSCRIBER SERVICES, WOODBURY, NY 11797-2999 USA SN 1063-7788 J9 PHYS ATOM NUCL+ JI Phys. Atom. Nuclei PD MAR PY 1999 VL 62 IS 3 BP 405 EP 420 PG 16 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 184EH UT WOS:000079597100005 ER PT J AU Alde, D Binon, F Blick, AM Bricman, C Boutemeur, M Dolgopolov, AV Donskov, SV Gouanere, M Inaba, S Inyakin, AV Khaustov, GV Kinashi, T Kobayashi, M Kolosov, VN Kondashov, AA Lednev, AA Mikhailov, YV Nakagawa, T Nakamura, T Peigneux, JP Polovnikov, SA Polyakov, VA Prokoshkin, YD Samoylenko, VD Shagin, PM Shimizu, H Singovsky, AV Sobol, AE Stroot, JP Sugonyaev, VP Takamatsu, K Tsuru, T Yasu, Y AF Alde, D Binon, F Blick, AM Bricman, C Boutemeur, M Dolgopolov, AV Donskov, SV Gouanere, M Inaba, S Inyakin, AV Khaustov, GV Kinashi, T Kobayashi, M Kolosov, VN Kondashov, AA Lednev, AA Mikhailov, YV Nakagawa, T Nakamura, T Peigneux, JP Polovnikov, SA Polyakov, VA Prokoshkin, YD Samoylenko, VD Shagin, PM Shimizu, H Singovsky, AV Sobol, AE Stroot, JP Sugonyaev, VP Takamatsu, K Tsuru, T Yasu, Y CA GAMS Collaboration TI Study of the reaction pi(-)p ->eta pi(0)n at 32, 38, and 100 GeV/c SO PHYSICS OF ATOMIC NUCLEI LA English DT Article ID SYSTEM AB The reaction pi(-)p --> eta pi(0)n at primary pi(-) meson momenta of 32, 38, and 100 GeV/c has been studied by using the GAMS facilities. A partial-wave analysis has been performed in the effective-mass range 0.77 less than or equal to M-eta pi 0 < 1.82 GeV/c(2). A peak associated with the a(2) meson is clearly seen in the P+-wave. The difference of the D+- and P+-wave phases changes abruptly in the region of the a(2) mass. A significant contribution of the P+ wave is observed at the a(2) mass value and above, but this wave does not show a clear-cut resonance behavior. No significant contribution from exchanges of unnatural spin-parity are observed with the exception of the S-wave contribution in the region of the a(0) mass and the D-0-wave contribution in the region of the a(2) mass. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Inst High Energy Phys, Protvino 142284, Moscow Oblast, Russia. Inst Interuniv Sci Nucl, B-1050 Brussels, Belgium. Lab Annecy Le Vieux Phys Particules, F-74941 Annecy Le Vieux, France. Natl Lab High Energy Phys, KEK, Tsukuba, Ibaraki 305, Japan. Free Univ Brussels, B-1050 Brussels, Belgium. Univ Munich, D-85748 Garching, Germany. Yamagata Univ, Yamagata 990, Japan. Tohoku Univ, Sendai, Miyagi 98077, Japan. Miyazaki Univ, Miyazaki 8892192, Japan. RP Alde, D (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 10 TC 11 Z9 11 U1 0 U2 0 PU MAIK NAUKA/INTERPERIODICA PUBL PI WOODBURY PA C/O AMERICAN INST PHYSICS, 500 SUNNYSIDE BLVD, MEMBER SUBSCRIBER SERVICES, WOODBURY, NY 11797-2999 USA SN 1063-7788 J9 PHYS ATOM NUCL+ JI Phys. Atom. Nuclei PD MAR PY 1999 VL 62 IS 3 BP 421 EP 434 PG 14 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 184EH UT WOS:000079597100006 ER PT J AU Cook, AW Bushe, WK AF Cook, AW Bushe, WK TI A subgrid-scale model for the scalar dissipation rate in nonpremixed combustion SO PHYSICS OF FLUIDS LA English DT Article AB A subgrid-scale model is discussed for the scalar dissipation rate in nonpremixed turbulent reacting Bows. The model contains a coefficient which is determined by assuming a form for the scalar energy spectrum. The model is tested a priori using Direct Numerical Simulation (DNS) results for a temporal reacting mixing layer. The estimated dissipation rates an in good agreement with dissipation rates computed directly from the DNS data. Furthermore, the assumed spectrum methodology is found to accurately predict the model coefficient, including its spatial and temporal variations. (C) 1999 American Institute of Physics. [S1070-6631(99)02203-5]. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Stanford Univ, Stanford, CA 94305 USA. RP Cook, AW (reprint author), Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 11 TC 15 Z9 16 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD MAR PY 1999 VL 11 IS 3 BP 746 EP 748 DI 10.1063/1.869945 PG 3 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 169XA UT WOS:000078773700024 ER PT J AU Grigorian, H Hermann, B Weber, F AF Grigorian, H Hermann, B Weber, F TI Quark-hadron phase transition in neutron stars SO PHYSICS OF PARTICLES AND NUCLEI LA English DT Article ID STABILITY; STRANGE AB In the first part of this paper we introduce a suitable formulation of the hydrodynamical description of compact stars in a curved space-time manifold using the tetrad formalism. In the second part of the paper we review new developments concerning the possibility of quark deconfinement in neutron stars. Contrary to earlier claims, it is shown that "neutron'' stars may very well contain quark matter in their cores, which may register itself in an observable signal-an anomaly in the braking index of pulsars. (C) 1999 American Institute of Physics. [S1063-7796(99)00302-2]. C1 Yerevan State Univ, Dept Phys, Yerevan 375049, Armenia. Univ Munich, Sekt Phys, D-80333 Munich, Germany. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Grigorian, H (reprint author), Yerevan State Univ, Dept Phys, Yerevan 375049, Armenia. NR 39 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1063-7796 J9 PHYS PART NUCLEI JI Phys. Part. Nuclei PD MAR-APR PY 1999 VL 30 IS 2 BP 156 EP 166 DI 10.1134/1.953102 PG 11 WC Physics, Particles & Fields SC Physics GA 193AX UT WOS:000080114000003 ER PT J AU Garabedian, P Ku, LP AF Garabedian, P Ku, LP TI Quasiaxially symmetric stellarators with three field periods SO PHYSICS OF PLASMAS LA English DT Article AB Compact hybrid configurations with two field periods have been studied recently as candidates for a proof of principle experiment at the Princeton Plasma Physics Laboratory. This project has led us to the discovery of a family of quasiaxially symmetric stellarators with three field periods that have significant advantages, although their aspect ratios are a little larger. They have reversed shear and perform better in a local analysis of ballooning modes. Nonlinear equilibrium and stability calculations predict that the average beta limit will be at least as high as 4% if the bootstrap current turns out to be as big as that expected in comparable tokamaks. The concept relies on a combination of helical fields and bootstrap current to achieve adequate rotational transform at low aspect ratio. (C) 1999 American Institute of Physics. [S1070-664X(99)03903-8]. C1 NYU, Courant Inst Math Sci, New York, NY 10012 USA. Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Garabedian, P (reprint author), NYU, Courant Inst Math Sci, 251 Mercer St, New York, NY 10012 USA. NR 5 TC 18 Z9 18 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAR PY 1999 VL 6 IS 3 BP 645 EP 648 DI 10.1063/1.873348 PG 4 WC Physics, Fluids & Plasmas SC Physics GA 169ZP UT WOS:000078780500003 ER PT J AU Held, ED Leboeuf, JN Carreras, BA AF Held, ED Leboeuf, JN Carreras, BA TI Magnetohydrodynamic calculations with a nonmonotonic q profile and equilibrium, sheared toroidal flow SO PHYSICS OF PLASMAS LA English DT Article ID MAGNETIC SHEAR; TEARING MODES; TOKAMAKS; MHD; CONFINEMENT; GEOMETRY; ROTATION AB The linear and nonlinear stability of a nonmonotonic q profile is examined using a reduced set of magnetohydrodynamic (MHD) equations with an equilibrium, sheared toroidal flow. The reversed shear profile is shown to be unstable to a rich variety of resistive MHD modes including pressure-driven instabilities and tearing instabilities possessing a tearing/interchange character at low Lundquist number, S, and taking on a double/triple tearing structure at high S. Linear calculations show that the destabilizing effect of toroidal velocity shear on tearing modes is enhanced at finite pressure. In addition, this velocity shear decreases the stabilizing effect of finite pressure seen previously for tearing modes at high S. Nonlinear calculations show the generation of a large, m=1, n=0, Reynolds-stress-driven poloidal flow in the absence of significant flow damping. Calculations in which the poloidal flow was heavily damped show that sub-Alfvenic, sheared toroidal flows have a minimal effect on weakly coupled, localized instabilities. (C) 1999 American Institute of Physics. [S1070-664X(99)00603-5]. C1 Univ Wisconsin, Ctr Plasma Theory & Computat, Madison, WI 53706 USA. Oak Ridge Natl Lab, Div Fus Energy, Oak Ridge, TN 37831 USA. RP Held, ED (reprint author), Univ Wisconsin, Ctr Plasma Theory & Computat, Madison, WI 53706 USA. NR 16 TC 13 Z9 13 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAR PY 1999 VL 6 IS 3 BP 837 EP 845 DI 10.1063/1.873323 PG 9 WC Physics, Fluids & Plasmas SC Physics GA 169ZP UT WOS:000078780500027 ER PT J AU Lopez-Bruna, D Newman, DE Carreras, BA Diamond, PH AF Lopez-Bruna, D Newman, DE Carreras, BA Diamond, PH TI Fluctuation level bursts in a model of internal transport barrier formation SO PHYSICS OF PLASMAS LA English DT Article ID MAGNETIC SHEAR DISCHARGES; CONFINEMENT BIFURCATION; ENERGY CONFINEMENT; POLOIDAL ROTATION; H TRANSITION; DIII-D; TOKAMAK; DYNAMICS; TURBULENCE; PLASMA AB A model of internal transport barriers (ITB) is developed that, in addition to the typical features of ITB models (the phase transition character with a power threshold, barrier front propagation, etc.), exhibits an oscillatory/bursty behavior close to the transition. This behavior comes from the competition between the driving and suppression mechanisms for the turbulence. The onset of the oscillations has a power threshold, P (osc), below the power threshold for the transition to the enhanced confinement regime, P (th). In the calculations, P (osc) similar to 0.5P (th). This suggests that the oscillations avoid an early transition at P (th) = P (osc), so any mechanism that eliminates the oscillations may lower the transition power. (C) 1999 American Institute of Physics. [S1070-664X(99)00903-9]. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. RP Lopez-Bruna, D (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Lopez Bruna, Daniel/L-6539-2014 NR 33 TC 8 Z9 8 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAR PY 1999 VL 6 IS 3 BP 854 EP 862 PG 9 WC Physics, Fluids & Plasmas SC Physics GA 169ZP UT WOS:000078780500029 ER PT J AU Paoletti, F Cardinali, A Bernabei, S Post-Zwicker, A Tighe, W Von Goeler, S AF Paoletti, F Cardinali, A Bernabei, S Post-Zwicker, A Tighe, W Von Goeler, S TI Experimental and theoretical investigation of local synergy between ion Bernstein and lower hybrid waves in the Princeton Beta Experiment-Modified SO PHYSICS OF PLASMAS LA English DT Article ID PBX-M TOKAMAK; QUASI-LINEAR ANALYSIS; CURRENT DRIVE; PROPAGATION; ABSORPTION; ELECTRONS; PROFILE AB The local synergistic behavior of lower hybrid and ion Bernstein waves on the Princeton Beta Experiment-Modified tokamak [Phys. Fluids B 2, 1271 (1990)] is experimentally studied using a two-dimensional hard x-ray camera. The hard x-ray bremsstrahlung emission from suprathermal electrons, generated with lower hybrid current drive, is enhanced during ion Bernstein wave power injection. This enhancement is observed in limited regions of space, suggesting the formation of localized current channels. The effects on plasma electrons during combined application of these two types of waves are theoretically investigated using a quasilinear model. The numerical code simultaneously solves the three-dimensional (R, Z, Phi) torbidal wave equation for the electric field, in the Wentzel-Kramers-Brillouin-Jeffrey approximation, and the Fokker-Planck equation for the distribution function in two dimensions (nu(parallel to), nu(perpendicular to)) with an added quasilinear diffusion coefficient. The radial profile of the noninductively generated current density, the transmitted power traces, and the total power damping curve are calculated. The beneficial effects of a combined utilization of ion Bernstein and lower hybrid waves on the current drive are emphasized. The numerical results are compared with the experimental observations. (C) 1999 American Institute of Physics. [S1070-664X(99)02503-3]. C1 Columbia Univ, Dept Appl Phys & Appl Math, New York, NY 10027 USA. ENEA Fus, Ctr Ric Energia Frascati, EURATOM Assoc, I-00044 Frascati, Italy. Princeton Univ, Plasma Phys Lab, Princeton, NJ 08543 USA. RP Paoletti, F (reprint author), Columbia Univ, Dept Appl Phys & Appl Math, 500 W 120th St, New York, NY 10027 USA. NR 26 TC 25 Z9 26 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAR PY 1999 VL 6 IS 3 BP 863 EP 872 DI 10.1063/1.873350 PG 10 WC Physics, Fluids & Plasmas SC Physics GA 169ZP UT WOS:000078780500030 ER PT J AU Hill, KW Scott, SD Bell, M Budny, R Bush, CE Clark, REH Denne-Hinnov, B Ernst, DR Hammett, GW Mikkelsen, DR Mueller, D Ongena, J Park, HK Ramsey, AT Synakowski, EJ Taylor, G Zarnstorff, MC AF Hill, KW Scott, SD Bell, M Budny, R Bush, CE Clark, REH Denne-Hinnov, B Ernst, DR Hammett, GW Mikkelsen, DR Mueller, D Ongena, J Park, HK Ramsey, AT Synakowski, EJ Taylor, G Zarnstorff, MC CA TFTR Grp TI Tests of local transport theory and reduced wall impurity influx with highly radiative plasmas in the tokamak fusion test reactor SO PHYSICS OF PLASMAS LA English DT Article ID ENHANCED CONFINEMENT DISCHARGES; POWER EXHAUST SOLUTIONS; DIVERTOR OPERATION; ENERGY CONFINEMENT; HEAT-TRANSPORT; STEADY-STATE; JET TOKAMAK; TFTR; ITER; STABILITY AB The electron temperature (T-e) profile in neutral beam-heated supershot plasmas (T-e0 similar to 6-7 keV ion temperature T-i0 similar to 15-20 keV, beam power P-b similar to 16 MW) was remarkably invariant when radiative losses were increased significantly through gas puffing of krypton and xenon in the Tokamak Fusion Test Reactor [McGuire et al., Phys. Plasmas 2, 2176 (1995)]. Trace impurity concentrations (n(z) /n(e) similar to 10(-3)) generated almost flat and centrally peaked radiation profiles, respectively, and increased the radiative losses to 45%-90% of the input power (from the normal similar to 25% ). Energy confinement was not degraded at radiated power fractions up to 80%. A 20%-30% increase in T-i, in spite of an increase in ion-electron power loss, implies a factor of similar to 3 drop in the local ion thermal diffusivity. These experiments form the basis for a nearly ideal test of transport theory, since the change in the beam heating power profile is modest, while the distribution of power flow between (1) radiation and (2) conduction plus convection changes radically and is locally measurable. The decrease in T-e was significantly less than predicted by two transport models and may provide important tests of more complete transport models. At input power levels of 30 MW, the increased radiation eliminated the catastrophic carbon influx (carbon "bloom'') and performance (energy confinement and neutron production) was improved significantly relative to that of matched shots without impurity gas puffing. (C) 1999 American Institute of Physics. [S1070-664X(99)02903-1]. C1 Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Hill, KW (reprint author), Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. RI Hammett, Gregory/D-1365-2011; Ernst, Darin/A-1487-2010 OI Hammett, Gregory/0000-0003-1495-6647; Ernst, Darin/0000-0002-9577-2809 NR 57 TC 28 Z9 28 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAR PY 1999 VL 6 IS 3 BP 877 EP 884 DI 10.1063/1.873327 PG 8 WC Physics, Fluids & Plasmas SC Physics GA 169ZP UT WOS:000078780500032 ER PT J AU Hahm, TS Beer, MA Lin, Z Hammett, GW Lee, WW Tang, WM AF Hahm, TS Beer, MA Lin, Z Hammett, GW Lee, WW Tang, WM TI Shearing rate of time-dependent E x B flow SO PHYSICS OF PLASMAS LA English DT Article ID GRADIENT-DRIVEN TURBULENCE; MAGNETIC SHEAR; GYROKINETIC EQUATIONS; TOKAMAK EDGE; PLASMA; TRANSPORT; CONFINEMENT; SIMULATIONS; MODES; FLUCTUATIONS AB Theory of ExB shear suppression of turbulence in toroidal geometry [Phys. Plasmas 2, 1648 (1995)] is extended to include fast time variations of the ExB flows often observed in nonlinear simulations of tokamak turbulence. It is shown that the quickly time varying components of the ExB flows, while they typically contribute significantly to the instantaneous ExB shearing rate, are less effective than the slowly time varying components in suppressing turbulence. This is because the shear flow pattern changes before eddies get distorted enough. The effective ExB shearing rate capturing this important physics is analytically derived and estimated from zonal flow statistics of gyrofluid simulation. This provides new insights into understanding recent gyrofluid and gyrokinetic simulations that yield a reduced, but not completely quenched, level of turbulence in the presence of turbulence-driven zonal flows. (C) 1999 American Institute of Physics. [S1070-664X(99)04603-0]. C1 Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Hahm, TS (reprint author), Princeton Univ, Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. RI Hammett, Gregory/D-1365-2011 OI Hammett, Gregory/0000-0003-1495-6647 NR 57 TC 186 Z9 186 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 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAR PY 1999 VL 6 IS 3 BP 922 EP 926 DI 10.1063/1.873331 PG 5 WC Physics, Fluids & Plasmas SC Physics GA 169ZP UT WOS:000078780500036 ER PT J AU Smitherman, DP Chrien, RE Hoffman, NM Magelssen, GR AF Smitherman, DP Chrien, RE Hoffman, NM Magelssen, GR TI The feedout process: Rayleigh-Taylor and Richtmyer-Meshkov instabilities in uniform, radiation-driven foils SO PHYSICS OF PLASMAS LA English DT Article ID THIN FLUID LAYER; NATIONAL-IGNITION-FACILITY; STRATIFIED FLUIDS; GROWTH; NOVA; PERTURBATIONS; EVOLUTION; PATTERNS; FUSION AB Observation of perturbation coupling between a Richtmyer-Meshkov-unstable interface on the cold surface of a radiatively-driven foil and the Rayleigh-Taylor-unstable hot surface is reported. For the 50 mu m wavelength studied, the combination of pulse length and foils thickness was found to affect the strength of instability coupling. Thick (86 mu m) foils with a 2.2 ns long pulse showed weak coupling between the two instabilities, while thin (35 mu m) foils showed strong, fast coupling. An intermediate (50 mu m) foil thickness with a cooler, 4.5 ns pulse showed a transition from weak to strong coupling during the pulse duration. Radiation-hydrodynamic simulations are in agreement with the experiments and provide insight into the coupling phenomenon. (C) 1999 American Institute of Physics. [S1070-664X(99)02103-5]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Wisconsin, Madison, WI USA. RP Smitherman, DP (reprint author), Univ Calif Los Alamos Natl Lab, MS F664, Los Alamos, NM 87545 USA. NR 32 TC 21 Z9 22 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAR PY 1999 VL 6 IS 3 BP 932 EP 939 DI 10.1063/1.873333 PG 8 WC Physics, Fluids & Plasmas SC Physics GA 169ZP UT WOS:000078780500038 ER PT J AU Smitherman, DP Chrien, RE Hoffman, NM Magelssen, GR AF Smitherman, DP Chrien, RE Hoffman, NM Magelssen, GR TI Feedout coupling of Richtmyer-Meshkov and Rayleigh-Taylor instabilities in stratified, radiation-driven foils SO PHYSICS OF PLASMAS LA English DT Article ID THIN FLUID LAYER; NATIONAL-IGNITION-FACILITY; GROWTH; EVOLUTION; PATTERNS; NOVA AB Coupling between Richtmyer-Meshkov- and Rayleigh-Taylor-unstable surfaces of indirectly driven, stratified, planar foils composed of an aluminum ablator and a beryllium payload carrying a machined initial perturbation was studied using radiographic techniques. The beryllium was transparent to the x-ray backlighter, allowing clear observation of the perturbation transport into the aluminum. The maximum perturbation amplitude (areal-mass difference) was smaller in the aluminum/beryllium foils than in equivalent pure aluminum foils, which could have been the result of shorter growth time, a lower differential acceleration coupling, or the density discontinuity at the aluminum/beryllium interface. Second and third harmonics were not observed in the composite foils. (C) 1999 American Institute of Physics. [S1070-664X(99)04403-1]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Wisconsin, Madison, WI USA. RP Smitherman, DP (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663,MS F664, Los Alamos, NM 87545 USA. NR 22 TC 6 Z9 6 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAR PY 1999 VL 6 IS 3 BP 940 EP 946 DI 10.1063/1.873334 PG 7 WC Physics, Fluids & Plasmas SC Physics GA 169ZP UT WOS:000078780500039 ER PT J AU Channell, PJ AF Channell, PJ TI Systematic solution of the Vlasov-Poisson equations for charged particle beams SO PHYSICS OF PLASMAS LA English DT Article AB Rapidly oscillating solutions of the Vlasov-Poisson equations are required when external forces are rapidly oscillating, as occurs in focusing systems for charged particle beams. Such systems are treated using a Hamiltonian averaging technique carried out to third order. As a result one can deal with the problems of matching, stability, and transient time evolution using the well-established techniques previously used for simpler, time-independent systems. (C) 1999 American Institute of Physics. [S1070-664X(99)03203-6]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Channell, PJ (reprint author), Univ Calif Los Alamos Natl Lab, MS H808, Los Alamos, NM 87545 USA. NR 12 TC 27 Z9 27 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAR PY 1999 VL 6 IS 3 BP 982 EP 993 DI 10.1063/1.873339 PG 12 WC Physics, Fluids & Plasmas SC Physics GA 169ZP UT WOS:000078780500044 ER PT J AU Vogt, R AF Vogt, R TI J/psi production and suppression SO PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS LA English DT Review DE quarkonium production; J/psi suppression; quark-gluon plasma; ultrarelativistic heavy-ion collisions ID NUCLEUS-NUCLEUS COLLISIONS; QUARK-GLUON-PLASMA; J-PSI-SUPPRESSION; HEAVY-ION COLLISIONS; TRANSVERSE-MOMENTUM DEPENDENCE; YAN CROSS-SECTIONS; PB-PB INTERACTIONS; TO-BACK JETS; DIMUON PRODUCTION; PAIR PRODUCTION AB In recent years, the J/psi signal in heavy-ion collisions at the CERN SPS has attracted much attention as a potential quark-gluon plasma signature. This review discusses the prediction of J/psi suppression and the systematics of this signature as a function of the transverse energy of the collision and the transverse momentum of the J/psi. Since J/psi suppression was already present in hadron-nucleus interactions, hadronic models of absorption by nucleons and scattering with comoving secondaries soon emerged. After a discussion of J/psi and other related production data in pp, pA, and AB interactions, hadronic suppression models are introduced and compared with the CERN SPS data. Plasma model predictions are also given for CERN SPS collisions as well as for the future RHIC and LHC heavy-ion colliders. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. RP Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. EM vogt@lbl.gov NR 198 TC 88 Z9 88 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-1573 EI 1873-6270 J9 PHYS REP JI Phys. Rep.-Rev. Sec. Phys. Lett. PD MAR PY 1999 VL 310 IS 4 BP 198 EP 260 PG 63 WC Physics, Multidisciplinary SC Physics GA 175QU UT WOS:000079106900001 ER PT J AU Gee, G AF Gee, G TI Probing of dimensional analysis reveals scaling, sapience and a Froudean slip SO PHYSICS TODAY LA English DT Letter C1 Pacific NW Lab, Richland, WA 99352 USA. RP Gee, G (reprint author), Pacific NW Lab, Richland, WA 99352 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD MAR PY 1999 VL 52 IS 3 BP 11 EP + PG 2 WC Physics, Multidisciplinary SC Physics GA 173DC UT WOS:000078965100003 ER PT J AU Ringo, R AF Ringo, R TI Samuel Bradley Burson - Obituary SO PHYSICS TODAY LA English DT Biographical-Item C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Ringo, R (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD MAR PY 1999 VL 52 IS 3 BP 108 EP + DI 10.1063/1.882540 PG 2 WC Physics, Multidisciplinary SC Physics GA 173DC UT WOS:000078965100022 ER PT J AU Baldwin, GC AF Baldwin, GC TI Untitled SO PHYSICS TODAY LA English DT Letter C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87544 USA. RP Baldwin, GC (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87544 USA. NR 3 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD MAR PY 1999 VL 52 IS 3 BP 117 EP 117 PG 1 WC Physics, Multidisciplinary SC Physics GA 173DC UT WOS:000078965100028 ER PT J AU Zhang, HX Zeevaart, JAD AF Zhang, HX Zeevaart, JAD TI An efficient Agrobacterium tumefaciens mediated transformation and regeneration system for cotyledons of spinach (Spinacia oleracea L) SO PLANT CELL REPORTS LA English DT Article DE spinach (Spinacia oleracea L.); regeneration; green-fluorescent protein; transformation; cotyledon ID PLANT-REGENERATION; GIBBERELLIC-ACID; CALLUS; HYPOCOTYL; SEGMENTS; PROTEIN; GROWTH; LIGHT AB An efficient transformation and regeneration system was established for the production of transgenic spinach (Spinacia oleracea L.) plants. Cotyledon explants were infected with Agrobacterium tumefaciens strain LBA4404 carrying the selectable marker gene, neomycin phospotransferase II (nptII), and the reporter gene smgfp, encoding soluble-modified green-fluorescent protein, driven by the cauliflower mosaic virus 35S promoter The infected explants were cultured on Murashige and Skoog medium, containing 1 mg/l benzyladenine and 0.4 mg/l naphthaleneacetic acid. Shoots were regenerated on selection medium containing 50 mg/l kanamycin. Regenerated kanamycin-resistant shoots were rooted on medium containing 1 mg/l indolebutyric acid and subsequently grown in soil in the greenhouse. Southern blot analysis indicated chat the smgfp gene bad been integrated into the spinach genome. Northern and Western blots showed that the smgfp gene was expressed in progeny plants. C1 Michigan State Univ, DOE, Plant Res Lab, E Lansing, MI 48824 USA. RP Zeevaart, JAD (reprint author), Michigan State Univ, DOE, Plant Res Lab, E Lansing, MI 48824 USA. NR 24 TC 24 Z9 27 U1 1 U2 7 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0721-7714 J9 PLANT CELL REP JI Plant Cell Reports PD MAR PY 1999 VL 18 IS 7-8 BP 640 EP 645 PG 6 WC Plant Sciences SC Plant Sciences GA 178TH UT WOS:000079282200020 ER PT J AU Anderson, GK Snyder, H Coogan, J AF Anderson, GK Snyder, H Coogan, J TI Oxidation of styrene in a silent discharge plasma SO PLASMA CHEMISTRY AND PLASMA PROCESSING LA English DT Article DE styrene; oxidation; silent discharge; plasma; dielectric barrier ID ORGANIC-COMPOUNDS; GLOW-DISCHARGE; POLYMERIZATION; SYSTEM AB A silent discharge plasma reactor has been developed to study the oxidation of styrene vapor in argon/oxygen mixtures. A number of analytical techniques were employed to determine the destruction efficiency and to characterize the intermediate products. The destruction efficiency was measured as a function of initial styrene concentration, temperature, and energy density of the plasma. The formation of solid products was observed in most experiments. Ar low temperature (100 degrees C), the solid deposit was polymeric in nature, while at high temperature (300 degrees C) the solid appeared to be amorphous carbon. A combination of high temperature and high energy density resulted in high destruction efficiency and minimal production of solid films. The destruction efficiency vs. energy density is shown to be more complex than a simple model predicting exponential behavior. Several reasons for the discrepancy are suggested. The "e-folding" energy density for the destruction of styrene is compared to literature values for other organic compounds, measured using similar types of plasma reactors. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Anderson, GK (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. NR 15 TC 26 Z9 26 U1 1 U2 8 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0272-4324 J9 PLASMA CHEM PLASMA P JI Plasma Chem. Plasma Process. PD MAR PY 1999 VL 19 IS 1 BP 131 EP 151 DI 10.1023/A:1021812201545 PG 21 WC Engineering, Chemical; Physics, Applied; Physics, Fluids & Plasmas SC Engineering; Physics GA 178GD UT WOS:000079257100007 ER PT J AU Ashkenazy, J Fruchtman, A Raitses, Y Fisch, NJ AF Ashkenazy, J Fruchtman, A Raitses, Y Fisch, NJ TI Modelling the behaviour of a Hall current plasma accelerator SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article; Proceedings Paper CT 25th EPS Conference on Controlled Fusion and Plasma Physics / International Congress on Plasma Physics CY JUN 29-JUL 03, 1998 CL PRAGUE, CZECH REPUBLIC SP European Phys Soc ID THRUSTERS AB A simple model for the operation of the Hall current plasma accelerator, a crossed field discharge device that accelerates a flow of quasi-neutral plasma, is used to calculate the performance of an actual device at various configurations and operating conditions. The solutions demonstrate that the performance, characterized by the ionized fraction of the flow, the mass-averaged exit flow velocity and the total efficiency, improves as the how rate or the accelerator length are increased at a given discharge voltage, trends that were also observed experimentally. Nevertheless, the calculated values for the longer lengths, especially the total efficiencies, are significantly higher than the measured ones, indicating the importance of an accurate solution of the electron energy equation and the need to include in the model plasma-wall interactions. C1 Soreq NRC, Propuls Phys Lab, IL-81800 Yavne, Israel. Ctr Technol Educ Holon, IL-58102 Holon, Israel. Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Ashkenazy, J (reprint author), Soreq NRC, Propuls Phys Lab, IL-81800 Yavne, Israel. NR 23 TC 6 Z9 7 U1 2 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAR PY 1999 VL 41 SU 3A BP A357 EP A364 DI 10.1088/0741-3335/41/3A/029 PG 8 WC Physics, Fluids & Plasmas SC Physics GA 187MY UT WOS:000079791600030 ER PT J AU Bell, MG Bell, RE Efthimion, PC Ernst, DR Fredrickson, ED Levinton, FM Manickam, J Mazzucato, E Schmidt, GL Synakowski, EJ Zarnstorff, MC AF Bell, MG Bell, RE Efthimion, PC Ernst, DR Fredrickson, ED Levinton, FM Manickam, J Mazzucato, E Schmidt, GL Synakowski, EJ Zarnstorff, MC CA TFTR Grp TI Core transport reduction in tokamak plasmas with modified magnetic shear SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article; Proceedings Paper CT 25th EPS Conference on Controlled Fusion and Plasma Physics / International Congress on Plasma Physics CY JUN 29-JUL 03, 1998 CL PRAGUE, CZECH REPUBLIC SP European Phys Soc ID FUSION TEST REACTOR; ELECTRIC-FIELD SHEAR; IMPROVED CONFINEMENT; POLOIDAL ROTATION; TFTR; DISCHARGES; TURBULENCE; PERFORMANCE; STABILIZATION; SUPPRESSION AB Spontaneous improvements of plasma confinement during auxiliary heating have been observed in many tokamaks when the q profile has been modified from its normal resistive equilibrium so that q > 1 and the magnetic shear is reduced or reversed in a region near the magnetic axis. The effects on the overall plasma confinement result from the formation in the plasma interior of transport barriers, regions where the thermal and particle transport coefficients are substantially reduced. These internal barriers are sometimes tied to unique magnetic surfaces, such as the surface where the shear reverses. The reduction in transport appears to result from the suppression of turbulence by sheared plasma How, which has now been measured in TFTR. Extensions of the theory for turbulence suppression show that this underlying paradigm may also explain other regimes of improved core confinement. The excitement generated by these discoveries must be tempered by the realization that transport and stability to pressure-driven MHD instabilities are intimately linked in these plasmas through the bootstrap current and the effect of the resulting current profile on the transport. Thus the development of control tools and strategies is essential if these improved regimes of confinement are to be exploited to improve the prospects for fusion energy production. C1 Princeton Univ, Plasma Phys Lab, Princeton, NJ 08544 USA. Fus Phys & Technol Inc, Torrance, CA USA. RP Bell, MG (reprint author), Princeton Univ, Plasma Phys Lab, POB 451, Princeton, NJ 08544 USA. RI Ernst, Darin/A-1487-2010 OI Ernst, Darin/0000-0002-9577-2809 NR 43 TC 30 Z9 30 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAR PY 1999 VL 41 SU 3A BP A719 EP A731 DI 10.1088/0741-3335/41/3A/065 PG 13 WC Physics, Fluids & Plasmas SC Physics GA 187MY UT WOS:000079791600066 ER PT J AU Fenstermacher, ME Boedo, J Isler, RC Leonard, AW Porter, GD Whyte, DG Wood, RD Allen, SL Brooks, NH Colchin, R Evans, TE Hill, DN Lasnier, CJ Lehmer, RD Mahdavi, MA Maingi, R Moyer, RA Petrie, TW Rognlien, TD Schaffer, MJ Stambaugh, RD Wade, MR Watkins, JG West, WP Wolf, N AF Fenstermacher, ME Boedo, J Isler, RC Leonard, AW Porter, GD Whyte, DG Wood, RD Allen, SL Brooks, NH Colchin, R Evans, TE Hill, DN Lasnier, CJ Lehmer, RD Mahdavi, MA Maingi, R Moyer, RA Petrie, TW Rognlien, TD Schaffer, MJ Stambaugh, RD Wade, MR Watkins, JG West, WP Wolf, N TI Physics of the detached radiative divertor regime in DIII-D SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article; Proceedings Paper CT 25th EPS Conference on Controlled Fusion and Plasma Physics / International Congress on Plasma Physics CY JUN 29-JUL 03, 1998 CL PRAGUE, CZECH REPUBLIC SP European Phys Soc ID CONVECTION; PLASMAS AB This paper summarizes results from a two-dimensional ('2D) physics analysis of the transition to and stable operation of the partially detached divertor (PDD) regime induced by deuterium injection in DIII-D. The analysis [I] shows that PDD operation is characterized by a radiation zone near the X-point at T-c similar to 8-15 eV which reduces the energy flux into the divertor and thereby also reduces the target plate heat flux, an ionization zone below the X-point which provides a deuterium ion source to fuel parallel flow down the outer divertor leg, an ion-neutral interaction zone in the outer leg which removes momentum and energy from the flow and finally a volume recombination zone above the target plate which reduces the particle Bur to the low levels measured on the plates and thereby also contributes to reduction in target plate heat Bur. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif San Diego, Fus Energy Res Program, La Jolla, CA 92093 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37830 USA. Gen Atom Co, San Diego, CA 92186 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Fenstermacher, ME (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94550 USA. NR 19 TC 19 Z9 19 U1 0 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAR PY 1999 VL 41 SU 3A BP A345 EP A355 DI 10.1088/0741-3335/41/3A/028 PG 11 WC Physics, Fluids & Plasmas SC Physics GA 187MY UT WOS:000079791600029 ER PT J AU Fisch, NJ Herrmann, MC AF Fisch, NJ Herrmann, MC TI A tutorial on alpha-channelling SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article; Proceedings Paper CT 25th EPS Conference on Controlled Fusion and Plasma Physics / International Congress on Plasma Physics CY JUN 29-JUL 03, 1998 CL PRAGUE, CZECH REPUBLIC SP European Phys Soc ID ION-BERNSTEIN WAVES; PLASMAS; TOKAMAK; ENERGY; SHEAR; EXCITATION; PARTICLES; POWER; TFTR AB One of the more ambitious uses of intense microwaves in tokamaks or in other magnetic confinement deuterium-tritium (DT) fusion devices would be to divert power from energetic alpha-particles to waves. This so-called 'alpha-channelling' would be a large step towards achieving economical fusion power. The intense waves, amplified by the substantial free energy in the alpha-particles, damp on fuel ions, resulting in a hot ion mode, doubling the fusion power of the reactor at the same confined pressure. If the waves damp preferentially on elections or ions travelling in one direction, current can be driven. This tutorial explains the key concepts and recent advances that lead us to believe in the plausibility of such an effect, at the same time showing how experiments to date give us a measure of confidence in both the simulations themselves, the underlying physical assumptions and ultimately the reasonableness of the application of these ideas to alpha-channelling in a tokamak reactor. C1 Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Princeton Univ, Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 22 TC 23 Z9 23 U1 1 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0741-3335 EI 1361-6587 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAR PY 1999 VL 41 SU 3A BP A221 EP A228 DI 10.1088/0741-3335/41/3A/015 PG 8 WC Physics, Fluids & Plasmas SC Physics GA 187MY UT WOS:000079791600016 ER PT J AU Glasser, AH Sovinec, CR Nebel, RA Gianakon, TA Plimpton, SJ Chu, MS Schnack, DD AF Glasser, AH Sovinec, CR Nebel, RA Gianakon, TA Plimpton, SJ Chu, MS Schnack, DD CA NIMROD Team TI The NIMROD code: a new approach to numerical plasma physics SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article; Proceedings Paper CT 25th EPS Conference on Controlled Fusion and Plasma Physics / International Congress on Plasma Physics CY JUN 29-JUL 03, 1998 CL PRAGUE, CZECH REPUBLIC SP European Phys Soc ID SEMI-IMPLICIT METHOD; MAGNETOHYDRODYNAMIC COMPUTATIONS; TOKAMAK DISCHARGES; SIMULATION AB NIMROD is a code development project designed to study long-wavelength, low-frequency, nonlinear phenomena in toroidal plasmas with realistic geometry and dynamics. The numerical challenges of solving the fluid equations for a fusion plasma are discussed and our discretization scheme is presented. Simulations of a resistive tearing mode show that time steps much greater than the Alfven time are possible without loss of accuracy. Validation tests of a resistive interchange mode in a shaped equilibrium, a ballooning mode and nonlinear activity in reversed-field pinches are described. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Wisconsin, Madison, WI 53706 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Gen Atom Co, San Diego, CA 92186 USA. Sci Applicat Int Corp, San Diego, CA 92121 USA. RP Glasser, AH (reprint author), Univ Calif Los Alamos Natl Lab, MS K717, Los Alamos, NM 87545 USA. NR 23 TC 54 Z9 54 U1 3 U2 10 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAR PY 1999 VL 41 SU 3A BP A747 EP A755 DI 10.1088/0741-3335/41/3A/067 PG 9 WC Physics, Fluids & Plasmas SC Physics GA 187MY UT WOS:000079791600068 ER PT J AU Kruer, WL Campbell, EM Decker, CD Wilks, SC Moody, J Orzechowski, T Powers, L Suter, LJ Afeyan, BB Dague, N AF Kruer, WL Campbell, EM Decker, CD Wilks, SC Moody, J Orzechowski, T Powers, L Suter, LJ Afeyan, BB Dague, N TI Strongly driven laser-plasma coupling SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article; Proceedings Paper CT 25th EPS Conference on Controlled Fusion and Plasma Physics / International Congress on Plasma Physics CY JUN 29-JUL 03, 1998 CL PRAGUE, CZECH REPUBLIC SP European Phys Soc ID STIMULATED BRILLOUIN-SCATTERING; IN-CELL SIMULATIONS; RAMAN-SCATTERING; HOHLRAUM PLASMAS; FILAMENTATION; FLUCTUATIONS; ABSORPTION; DEPENDENCE; INTENSITY; IGNITION AB An improved understanding of strongly driven laser-plasma coupling is important for optimal use of the National Ignition Facility (NIF) for both inertial fusion and for a variety of advanced applications. Such applications range from high-energy x-ray sources and high-temperature hohlraums to fast ignition and laser radiography. We discuss a novel model for the scaling of strongly driven stimulated Brillouin and Raman scattering. This model postulates an intensity-dependent correlation length associated with spatial incoherence due to filamentation and stimulated forward scattering. We first describe the model and then relate it to a variety of experiments. Particular attention is paid to high-temperature hohlraum experiments, which exhibit low to modest stimulated Brillouin scattering even though this instability is strongly driven. We also briefly discuss the strongly nonlinear interaction physics for efficient generation of high-energy electrons either by irradiating a large plasma with near quarter-critical density or by irradiating overdense targets with ultra-intense laser light. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Polymath Associates, Pleasanton, CA 94566 USA. CEA, DRIF, DPTA, F-91680 Bruyeres Le Chatel, France. RP Kruer, WL (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94550 USA. NR 36 TC 3 Z9 4 U1 0 U2 10 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAR PY 1999 VL 41 SU 3A BP A409 EP A417 DI 10.1088/0741-3335/41/3A/033 PG 9 WC Physics, Fluids & Plasmas SC Physics GA 187MY UT WOS:000079791600034 ER PT J AU Matzen, MK Deeney, C Leeper, RJ Porter, JL Spielman, RB Chandler, GA Derzon, MS Douglas, MR Fehl, DL Hebron, DE Nash, T Olson, RE Ruggles, LE Sanford, TWL Seamen, JF Struvel, KW Stygar, WA Peterson, DL AF Matzen, MK Deeney, C Leeper, RJ Porter, JL Spielman, RB Chandler, GA Derzon, MS Douglas, MR Fehl, DL Hebron, DE Nash, T Olson, RE Ruggles, LE Sanford, TWL Seamen, JF Struvel, KW Stygar, WA Peterson, DL TI Fast z-pinches as dense plasma, intense x-ray sources for plasma physics and fusion applications SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article; Proceedings Paper CT 25th EPS Conference on Controlled Fusion and Plasma Physics / International Congress on Plasma Physics CY JUN 29-JUL 03, 1998 CL PRAGUE, CZECH REPUBLIC SP European Phys Soc ID ARRAY Z-PINCH; POWER; IMPLOSIONS; OPTIMIZATION; RADIUS AB As a result of advances in fast pulsed-power technology and cylindrical load fabrication, the Z pulsed-power accelerator at Sandia National Laboratories drives currents approaching 20 MA with a rise time of approximately 100 ns through cylindrically-symmetric loads (typically a cylindrical array consisting of a few hundred wires) to produce plasma densities in excess of 10(21) ions cc(-1), x-ray output energies approaching 2 MJ, radiation pulses as short as 4 ns and peak x-ray powers as high as 280 +/- 40 TW. More than 15% of the stored electrical energy in the Z pulsed-power accelerator is converted into x-rays. The plasma pressures at peak compression are several TPa with electron temperatures that can exceed 3 keW at containment magnetic fields exceeding 1000 T. Depending on the atomic number and composition of the imploding plasma, these z-pinches can be tailored to produce intense sources of thermal x-rays, keV x-rays or neutrons. Although applications of these x-ray sources have included research in radiation material interaction, equations of state, opacity, astrophysics and x-ray lasers, the principal focus of the present research is to use them for indirect-drive inertial confinement fusion (ICF). C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Matzen, MK (reprint author), Sandia Natl Labs, MS-1187,POB 5800, Albuquerque, NM 87185 USA. NR 30 TC 17 Z9 17 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAR PY 1999 VL 41 SU 3A BP A175 EP A184 DI 10.1088/0741-3335/41/3A/011 PG 10 WC Physics, Fluids & Plasmas SC Physics GA 187MY UT WOS:000079791600012 ER PT J AU Ongena, J Messiaen, AM Unterberg, B Budny, RV Bush, CE Hill, K Hoang, GT Jackson, G Kallenbach, A Monier-Garbet, P Mueller, D Murakami, M Staebler, G Ryter, F Wade, M Bell, M Boedo, J Bonheure, G Dumortier, P Durodie, F Finken, KH Fuchs, G Giesen, B Hutteman, P Jaspers, R Koch, R Kramer-Flecken, A Mertens, P Moyer, R Pospieszczyk, A Ramsey, A Samm, U Sauer, M Schweer, B Uhlemann, R Vandenplas, PE Van Oost, G Vervier, M Van Wassenhove, G Waidmann, G Weynants, RR Wolf, GH AF Ongena, J Messiaen, AM Unterberg, B Budny, RV Bush, CE Hill, K Hoang, GT Jackson, G Kallenbach, A Monier-Garbet, P Mueller, D Murakami, M Staebler, G Ryter, F Wade, M Bell, M Boedo, J Bonheure, G Dumortier, P Durodie, F Finken, KH Fuchs, G Giesen, B Hutteman, P Jaspers, R Koch, R Kramer-Flecken, A Mertens, P Moyer, R Pospieszczyk, A Ramsey, A Samm, U Sauer, M Schweer, B Uhlemann, R Vandenplas, PE Van Oost, G Vervier, M Van Wassenhove, G Waidmann, G Weynants, RR Wolf, GH CA ASDEX Upgrade Team DIII D Team TEXTOR 94 Team TFTR Team Tore Supra Team TI Overview of experiments with radiation cooling at high confinement and high density in limited and diverted discharges SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article; Proceedings Paper CT 25th EPS Conference on Controlled Fusion and Plasma Physics / International Congress on Plasma Physics CY JUN 29-JUL 03, 1998 CL PRAGUE, CZECH REPUBLIC SP European Phys Soc ID IMPURITY INJECTION; ASDEX UPGRADE; ISX-B; TEXTOR-94; PLASMAS; TOKAMAK; ENERGY; ITER AB An overview is presented of recent experiments with radiating mantles on limiter and divertor machines, realizing simultaneously high confinement and high density at high-radiation levels. A variety of operational regimes has been observed and the characteristics of each are documented. High-performance plasmas (i.e. edge localized mode (ELM)-free H-mode confinement quality f(H93) greater than or equal to 1 and normalized beta values beta(n) greater than or equal to 2 simultaneously) with radiating mantles have been demonstrated under quasistationary conditions during the maximum flattop time of the machine (equal to tens of confinement times) on DIII-D and TEXTOR-94. Maximum values for beta(n) up to 4 and for the advanced tokamak confinement-stability product beta(n) x f(L89) up to 13, have been obtained in very high confinement mode (VH-mode) like discharges with radiating mantles in DIII-D. There is a striking similarity between improved ohmic confinement discharges (with or without Ne seeding) and radiating mantle discharges, indicating a possible common origin for the confinement improvement observed. Possible scenarios for the application of radiating mantles on larger machines such as JET and JT-60U are indicated. C1 Assoc EURATOM Belgian State, Lab Phys Plasmas, B-1000 Brussels, Belgium. Koninklijke Mil Sch, Brussels, Belgium. Forschungszentrum Julich, Inst Plasma Phys, EURATOM Assoc, D-52425 Julich, Germany. Princeton Univ, Princeton, NJ 08543 USA. Oak Ridge Natl Lab, Oak Ridge, TN USA. CEA Cadarache, Dept REch Fus Controlee, SEA Fus, EURATOM Assoc, F-13108 St Paul Les Durance, France. Gen Atom Co, San Diego, CA 92186 USA. Max Planck Inst Plasma Phys, EURATOM Assoc, D-85748 Garching, Germany. Univ Calif San Diego, Dept Appl Mech & Engn Sci, Fus Energy Res Program, La Jolla, CA 92093 USA. EURATOM, Assoc FOM, FOM Inst Plasmafys Rijnhuizen, Nieuwegein, Netherlands. RP Assoc EURATOM Belgian State, Lab Phys Plasmas, B-1000 Brussels, Belgium. RI Artaud, Jean-Francois/G-8480-2011; ANIEL, Thierry/G-8734-2011; Artaud, Jean-Francois/J-2068-2012 OI ANIEL, Thierry/0000-0002-2598-9551; NR 36 TC 40 Z9 41 U1 1 U2 8 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0741-3335 EI 1361-6587 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAR PY 1999 VL 41 SU 3A BP A379 EP A399 DI 10.1088/0741-3335/41/3A/031 PG 21 WC Physics, Fluids & Plasmas SC Physics GA 187MY UT WOS:000079791600032 ER PT J AU Ryutov, DD AF Ryutov, DD TI Landau damping: half a century with the great discovery SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article; Proceedings Paper CT 25th EPS Conference on Controlled Fusion and Plasma Physics / International Congress on Plasma Physics CY JUN 29-JUL 03, 1998 CL PRAGUE, CZECH REPUBLIC SP European Phys Soc ID COLD INHOMOGENEOUS PLASMA; ELECTROSTATIC OSCILLATIONS; EQUATION APPROACH; WAVES AB A brief summary is given of the early studies of Landau damping, followed by a discussion of the issues of singularities in the distribution function, reversibility and nonlinear constraints. A difference is emphasized between the evolution of a single-scale localized Langmuir perturbation and a long quasimonochromatic wavetrain. Applicability conditions of the quasilinear approximation are discussed. Examples of the use of the concept of Landau damping in hydrodynamics, astrophysics and other systems are presented. C1 Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NR 51 TC 32 Z9 32 U1 2 U2 5 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0741-3335 EI 1361-6587 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAR PY 1999 VL 41 SU 3A BP A1 EP A12 DI 10.1088/0741-3335/41/3A/001 PG 12 WC Physics, Fluids & Plasmas SC Physics GA 187MY UT WOS:000079791600002 ER PT J AU Shukla, PK Silva, LO Bethe, H Bingham, R Dawson, JM Stenflo, L Mendonca, JT Dalhed, S AF Shukla, PK Silva, LO Bethe, H Bingham, R Dawson, JM Stenflo, L Mendonca, JT Dalhed, S TI The physics of collective neutrino-plasma interactions SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article; Proceedings Paper CT 25th EPS Conference on Controlled Fusion and Plasma Physics / International Congress on Plasma Physics CY JUN 29-JUL 03, 1998 CL PRAGUE, CZECH REPUBLIC SP European Phys Soc ID MAGNETIC-FIELDS; DENSE-PLASMAS; OSCILLATIONS; MATTER; BEAMS AB A review of recent work on collective neutrino-plasma interactions is presented. The basic physical concepts of this new field as well as some possible astrophysical problems where the physics of collective neutrino-plasma interactions can have a radical impact, are discussed. C1 Ruhr Univ Bochum, Fak Phys & Astron, Inst Theoret Phys 4, D-44780 Bochum, Germany. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Cornell Univ, Dept Phys, Ithaca, NY 14853 USA. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Umea Univ, Dept Plasma Phys, S-90187 Umea, Sweden. Inst Super Tecn, Ctr Fis Plasmas, GoLP, P-1096 Lisbon, Portugal. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Shukla, PK (reprint author), Ruhr Univ Bochum, Fak Phys & Astron, Inst Theoret Phys 4, D-44780 Bochum, Germany. RI Silva, Luis/C-3169-2009; Shukla, Padma Kant/E-9077-2011 OI Silva, Luis/0000-0003-2906-924X; NR 25 TC 11 Z9 11 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAR PY 1999 VL 41 SU 3A BP A699 EP A707 DI 10.1088/0741-3335/41/3A/063 PG 9 WC Physics, Fluids & Plasmas SC Physics GA 187MY UT WOS:000079791600064 ER PT J AU Hino, T Prausnitz, JM AF Hino, T Prausnitz, JM TI Hard-sphere-chain equations of state for lyotropic polymer liquid crystals SO POLYMER LA English DT Article DE equation of state; lyotropic polymer liquid crystals; Onsager theory ID CONCENTRATED-SOLUTIONS; MOLECULES; EQUILIBRIUM; TRANSITION; SIMULATION; FLUIDS; SYSTEM; RODS AB Using Parsons-type scaling, the Onsager theory for the isotropic-nematic (I-N) transition of rigid-rod lyotropic polymer liquid crystals is combined with the equation of state for hard-sphere-chain fluids of Chapman et al. and that of Hu et al. The equation of Hu et al. gives the I-N transition pressure and density in good agreement with computer simulation by Wilson and Alien for a semi-flexible hard-sphere chain consisting of seven segments. For real semi-flexible polymers, we follow the Khokhlov-Semenov theory of persistent chains that introduces chain flexibility into the Onsager theory. Using a consistent procedure to regress the equation-of-state parameters, the equations of Chapman et al. and Hu et al. are also compared with the theory of DuPre and Yang that uses the equation of Lee for hard spherocylinders. These models are compared with experiment for two binary polymer solutions containing poly(hexyl isocyanate) and another solution containing polysaccharide schizophyllan. The concentration of polymer at the I-N transition is predicted as a function of the molecular weight of polymer. All models perform similarly and show semi-quantitative agreement with experiment. (C) 1998 Elsevier Science Ltd. All rights reserved. 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 26 TC 8 Z9 9 U1 4 U2 10 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0032-3861 J9 POLYMER JI Polymer PD MAR PY 1999 VL 40 IS 5 BP 1241 EP 1250 DI 10.1016/S0032-3861(98)00265-1 PG 10 WC Polymer Science SC Polymer Science GA 137XN UT WOS:000076942500017 ER PT J AU del Cueto, JA von Roedern, B AF del Cueto, JA von Roedern, B TI Temperature-induced changes in the performance of amorphous silicon multi-junction modules in controlled light-soaking SO PROGRESS IN PHOTOVOLTAICS LA English DT Article ID TECHNICAL EVALUATION; SYSTEMS; NREL AB We extended our light-soaking tests of amorphous silicon (a-Si) modules, which were previously stabilized in light-soaking experiments conducted at 50 degrees C and 35 degrees C module temperatures for a combined total of 1840 h, to further light exposure at a lower temperature (25 degrees C). We definitely establish that changes in the exposure temperature significantly modify module performance. Furthermore, we have determined that subsequent degradation observed upon light exposure at a lower temperature is completely recovered to start-of-test values within the accuracy of our measurements, as the operating temperature is increased again to 50 degrees C. The behavior is qualitatively similar in all modules tested, suggesting that the phenomena observed are governed by fundamental a-Si properties. This conduct is consistent with the annual variations observed for a-Si modules and systems deployed in the field, at climates that undergo significant temperature variations between winter and summer seasons. Because we have emulated the annual winter-summer oscillations twice in a controlled-climate, light-soaking chamber and because module performance was always determined from simulator measurements performed at standard conditions, it is hard to defend the notion that the changes observed are either spectral or spectrally induced in nature. Published in 1999 by John Wiley & Sons, Ltd. This article is a US government work and is in the public domain in the Untied States. C1 Natl Renewable Energy Lab, Natl Ctr Photovoltaics, Golden, CO 80401 USA. RP del Cueto, JA (reprint author), Natl Renewable Energy Lab, Natl Ctr Photovoltaics, 1617 Cole Blvd, Golden, CO 80401 USA. NR 14 TC 36 Z9 36 U1 0 U2 4 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 1062-7995 J9 PROG PHOTOVOLTAICS JI Prog. Photovoltaics PD MAR-APR PY 1999 VL 7 IS 2 BP 101 EP 112 DI 10.1002/(SICI)1099-159X(199903/04)7:2<101::AID-PIP247>3.0.CO;2-2 PG 12 WC Energy & Fuels; Materials Science, Multidisciplinary; Physics, Applied SC Energy & Fuels; Materials Science; Physics GA 196UE UT WOS:000080325300002 ER PT J AU Adams, J Maslin, M Thomas, E AF Adams, J Maslin, M Thomas, E TI Sudden climate transitions during the Quaternary SO PROGRESS IN PHYSICAL GEOGRAPHY LA English DT Review DE climate change; Heinrich events; interstadials; Quaternary; Younger Dryas ID NORTH-ATLANTIC OCEAN; LAST INTERGLACIAL PERIOD; GREENLAND ICE-SHEET; HEINRICH EVENTS; YOUNGER-DRYAS; SEA-LEVEL; THERMOHALINE CIRCULATION; BENTHIC FORAMINIFERA; MILANKOVITCH THEORY; GLACIAL PERIOD AB The time span of the past few million years has been punctuated by many rapid climate transitions, most of them on timescales of centuries to decades. The most detailed information is available for the Younger Dryas-to-Holocene stepwise change around 11 500 years ago, which seems to have occurred over a few decades. The speed of this change is probably representative of similar but less well studied climate transitions during the last few hundred thousand years. These include sudden cold events (Heinrich events/stadials), warm events (interstadials) and the beginning and ending of long warm phases, such as the Eemian interglacial. Detailed analysis of terrestrial and marine records of climate change will, however, be necessary before we can say confidently on what timescale these events occurred; they almost certainly did not take longer than a few centuries. Various mechanisms, involving changes in ocean circulation and biotic productivity, changes in atmospheric concentrations of greenhouse gases and haze particles, and changes in snow and ice cover, have been invoked to explain sudden regional and global transitions. We do not know whether such changes could occur in the near future as a result of human effects on climate. Phenomena such as the Younger Dryas and Heinrich events might only occur in a 'glacial' world with much larger ice sheets and more extensive sea-ice cover. A major sudden cold event, however, did probably occur under global climate conditions similar to those of the present, during the Eemian interglacial around 122 000 years ago. Less intensive, but significant rapid climate changes also occurred during the present (Holocene) interglacial, with cold and dry phases occurring on a 1500-year cycle, and with climate transitions on a decade-to-century timescale. In the past few centuries, smaller transitions (such as the ending of the Little Ice Age at about AD 1650) probably occurred over only a few decades at most. All evidence indicates that long-term climate change occurs in sudden jumps rather than incremental changes. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. UCL, Dept Geog, Environm Change Res Ctr, London WC1H 0AP, England. Yale Univ, Dept Geol & Geophys, Ctr Study Global Change, New Haven, CT 06520 USA. Wesleyan Univ, Dept Earth & Environm Sci, Middletown, CT 06459 USA. RP Adams, J (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. RI Thomas, Ellen/E-5573-2011 OI Thomas, Ellen/0000-0002-7141-9904 NR 165 TC 99 Z9 103 U1 2 U2 44 PU SAGE PUBLICATIONS LTD PI LONDON PA 1 OLIVERS YARD, 55 CITY ROAD, LONDON EC1Y 1SP, ENGLAND SN 0309-1333 J9 PROG PHYS GEOG JI Prog. Phys. Geogr. PD MAR PY 1999 VL 23 IS 1 BP 1 EP 36 PG 36 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 176YR UT WOS:000079180400001 ER PT J AU Wu, ZN Goldstein, B Laue, TM Liparoto, SE Nemeth, MJ Ciardelli, TL AF Wu, ZN Goldstein, B Laue, TM Liparoto, SE Nemeth, MJ Ciardelli, TL TI Solution assembly of the pseudo-high affinity and intermediate affinity interleukin-2 receptor complexes SO PROTEIN SCIENCE LA English DT Article DE coiled-coil; cytokine receptor; interleukin-2; radio-ligand binding ID HETERODIMERIC COILED-COIL; SURFACE-PLASMON RESONANCE; LIGAND-BINDING; CRYSTAL-STRUCTURE; LEUCINE ZIPPERS; GAMMA-CHAIN; T-CELL; BETA; EXPRESSION; DISSOCIATION AB The high affinity interleukin-2 receptor is composed of three cell surface subunits, IL-2R alpha, IL-2R beta, and IL-2R gamma. Functional forms of the IL-2 receptor exist, however, that enlist only two of the three subunits. On activated T-cells, the alpha- and beta-subunits combine as a preformed heterodimer (the pseudo-high affinity receptor) that serves to capture IL-2. On a subpopulation of natural killer cells, the beta- and gamma-subunits interact in a ligand-dependent manner to form the intermediate affinity receptor site. Previously, we have demonstrated the feasibility of employing coiled-coil molecular recognition for the solution assembly of a heteromeric IL-2 receptor complex. In that study, although the receptor was functional, the coiled-coil complex was a trimer rather than the desired heterodimer. We have now redesigned the hydrophobic heptad sequences of the coiled-coils to generate soluble forms of both the pseudo-high affinity and the intermediate affinity heterodimeric IL-2 receptors. The properties of these complexes were examined and their relevance to the physiological IL-2 receptor mechanism is discussed. C1 Dartmouth Med Sch, Dept Pharmacol & Toxicol, Hanover, NH 03755 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ New Hampshire, Dept Biochem & Mol Biol, Durham, NH 03867 USA. Vet Adm Hosp, Res Serv, White River Junction, VT 05009 USA. RP Ciardelli, TL (reprint author), Vet Adm Hosp, Res Serv, White River Junction, VT 05009 USA. EM ciardelli@dartmouth.edu FU NCI NIH HHS [CA23108]; NIAID NIH HHS [AI34331]; NIGMS NIH HHS [GM35556] NR 40 TC 9 Z9 9 U1 0 U2 0 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA SN 0961-8368 J9 PROTEIN SCI JI Protein Sci. PD MAR PY 1999 VL 8 IS 3 BP 482 EP 489 PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 174HH UT WOS:000079028300002 PM 10091650 ER PT J AU Raffen, R Dieckman, LJ Szpunar, M Wunschl, C Pokkuluri, PR Dave, P Stevens, PW Cai, XY Schiffer, M Stevens, FJ AF Raffen, R Dieckman, LJ Szpunar, M Wunschl, C Pokkuluri, PR Dave, P Stevens, PW Cai, XY Schiffer, M Stevens, FJ TI Physicochemical consequences of amino acid variations that contribute to fibril formation by immunoglobulin light chains SO PROTEIN SCIENCE LA English DT Article DE amyloid fibril; immunoglobulin light-chain variable domain; light-chain dimer; protein aggregation; protein stability; site-directed mutagenesis ID BENCE-JONES PROTEINS; AMYLOID FIBRILS; STAPHYLOCOCCAL NUCLEASE; THIOFLAVINE-T; IN-VITRO; DENATURATION; AGGREGATION; MUTAGENESIS; STABILITY; INVITRO AB The most common form of systemic amyloidosis originates from antibody light chains. The large number of amino acid variations that distinguish amyloidogenic from nonamyloidogenic light chain proteins has impeded our understanding of the structural basis of light-chain fibril formation. Moreover, even among the subset of human light chains that are amyloidogenic, many primary structure differences are found. We compared the thermodynamic stabilities of two recombinant kappa 4 light-chain variable domains (V(L)s) derived from amyloidogenic light chains with a V-L from a benign light chain. The amyloidogenic V(L)s were significantly less stable than the benign V-L. Furthermore, only the amyloidogenic V(L)s formed fibrils under native conditions in an in vitro fibril formation assay. We used site-directed mutagenesis to examine the consequences of individual amino acid substitutions found in the amyloidogenic V(L)s on stability and fibril formation capability. Both stabilizing and destabilizing mutations were found; however, only destabilizing mutations induced fibril formation in vitro. We found that fibril formation by the benign V-L could be induced by low concentrations of a denaturant. This indicates that there are no structural or sequence-specific features of the benign V-L that are incompatible with fibril formation, other than its greater stability. These studies demonstrate that the V-L beta-domain structure is vulnerable to destabilizing mutations at a number of sites, including complementarity determining regions (CDRs), and that loss of variable domain stability is a major driving force in fibril formation. C1 Argonne Natl Lab, Ctr Mechanist Biol & Biotechnol, Argonne, IL 60439 USA. RP Stevens, FJ (reprint author), Argonne Natl Lab, Ctr Mechanist Biol & Biotechnol, 9700 S Cass Ave,Bldg 202,A-141, Argonne, IL 60439 USA. EM fstevens@anlcmb.bim.anl.gov FU NIDDK NIH HHS [DK43757]; NIGMS NIH HHS [GM16829] NR 49 TC 114 Z9 120 U1 1 U2 6 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA SN 0961-8368 J9 PROTEIN SCI JI Protein Sci. PD MAR PY 1999 VL 8 IS 3 BP 509 EP 517 PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 174HH UT WOS:000079028300005 PM 10091653 ER PT J AU Turner, MS AF Turner, MS TI Cosmology solved? Quite possibly! SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID INFLATIONARY UNIVERSE; PERTURBATIONS; CONSTANT AB The discovery of the cosmic microwave background (CMB) in 1964 by Penzias and Wilson led to the establishment of the hot big bang cosmological model some 10 years later. Discoveries made in 1998 may ultimately have as profound an effect on our understanding of the origin and evolution of the universe. Taken at face value, they confirm the basic tenets of inflation + cold dark matter, a bold and expansive theory that addresses all the fundamental questions left unanswered by the hot big bang model and holds that the universe is flat, slowly moving elementary particles provide the cosmic infrastructure, and quantum fluctuations seeded all the structure seen in the universe today. Just as it took a decade to establish the hot big bang model after the discovery of the CMB, it will likely take another 10 years to establish the latest addition to the standard cosmology and make the answer to "Cosmology solved?" "YES!" Whether or not 1998 proves to be a cosmic milestone, the coming avalanche of high-quality cosmological data promises to make the next 20 years an extremely exciting period for cosmology. C1 Univ Chicago, Enrico Fermi Inst, Dept Astron & Astrophys, Chicago, IL 60637 USA. Univ Chicago, Enrico Fermi Inst, Dept Phys, Chicago, IL 60637 USA. Fermi Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. RP Turner, MS (reprint author), Univ Chicago, Enrico Fermi Inst, Dept Astron & Astrophys, Chicago, IL 60637 USA. NR 30 TC 21 Z9 21 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD MAR PY 1999 VL 111 IS 757 BP 264 EP 273 DI 10.1086/316325 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 177AM UT WOS:000079185100004 ER PT J AU Cook, KH Mateo, M Olszewski, EW Vogt, SS Stubbs, C Diercks, A AF Cook, KH Mateo, M Olszewski, EW Vogt, SS Stubbs, C Diercks, A TI The systemic velocity and internal kinematics of the dwarf galaxy LGS 3: An optical foray beyond the Milky Way SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID NEUTRAL INTERSTELLAR-MEDIUM; STAR-FORMATION HISTORY; TO-LIGHT RATIOS; LOCAL GROUP; URSA-MINOR; STELLAR POPULATIONS; SPHEROIDAL GALAXIES; ELLIPTIC GALAXY; MASS; DRACO AB We have obtained radial velocities of three K giants and one faint carbon star in LGS 3, a dwarf companion of M31, based on 12 individual spectra obtained with the HIRES spectrograph on the Keck I telescope. The mean precision of these measurements is 3.8 km s(-1). The mean systemic velocity of LGS 3 is -282.2 +/- 3.5 km s(-1). Monte Carlo simulations that take into account the individual velocity uncertainties and the maximum observed velocity difference reveal that the central velocity dispersion of LGS 3 is in the range 2.6-30.5 km s(-1), with 95% confidence; the most likely value for the central dispersion is 7.9(-2.9)(+5.3) km s(-1). These results agree with the kinematics of H I gas in LGS 3. This contrasts with the tendency for the gas and stars in other low-luminosity Local Group dwarfs to exhibit distinct spatial and kinematic properties. Taking into account the relative youth of LGS 3, we conclude that the "asymptotic" MIL ratio-the value the galaxy would exhibit if it were composed only of ancient stars-is M/L(V,LGS3) greater than or equal to 11 (at a 97.5% confidence level), with a most probable value of 95(-56)(+175). These values are consistent with the M/L, ratios observed in other well-studied early-type dwarfs of the Local Group. We have also estimated the mass of LGS 3 using modified Newtonian dynamics. These data represent the first moderately high precision optical spectra of giants in a dwarf system beyond the Galactic halo. We suggest future studies that are now feasible to study the dynamics of dwarf galaxies throughout the Local Group and beyond. C1 Lawrence Livermore Natl Lab, Expt Astrophys Lab, Livermore, CA 94550 USA. Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Calif Santa Cruz, Lick Observ, UCO, Santa Cruz, CA 95064 USA. Univ Washington, Dept Astron, Seattle, WA 98195 USA. RP Cook, KH (reprint author), Lawrence Livermore Natl Lab, Expt Astrophys Lab, POB 808,MS L-401, Livermore, CA 94550 USA. EM kcook@llnl.gov; mateo@astro.lsa.umich.edu; edo@as.arizona.edu; vogt@ucolick.org; stubbs@astro.washington.edu; diercks@astro.washington.edu RI Stubbs, Christopher/C-2829-2012 OI Stubbs, Christopher/0000-0003-0347-1724 NR 42 TC 16 Z9 16 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD MAR PY 1999 VL 111 IS 757 BP 306 EP 312 DI 10.1086/316339 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 177AM UT WOS:000079185100008 ER PT J AU Bradley, PD Rosenfeld, AB Allen, B Coderre, J Capala, J AF Bradley, PD Rosenfeld, AB Allen, B Coderre, J Capala, J TI Performance of silicon microdosimetry detectors in boron neutron capture therapy SO RADIATION RESEARCH LA English DT Article AB Reverse-biased silicon p-n junction arrays using Silicon-On-Insulator technology have been proposed as microdosimeters, The performance of such detectors in boron neutron capture therapy (BNCT) is discussed. This work provides the first reported measurements using boron-coated silicon diode arrays as microdosimeters in BNCT, Results are in good agreement with measurements with gas proportional counters. Various boron-coating options are investigated along with device orientation effects. Finally, U-235 coating is tested to simulate the behavior of the device in a heavy-ion therapy beam. (C) 1999 by Radiation Research Society. C1 Univ Wollongong, Radiat Phys Grp, Wollongong, NSW 2522, Australia. St George Hosp, Canc Care Ctr, Kogarah, NSW 2217, Australia. Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. RP Bradley, PD (reprint author), Univ Wollongong, Radiat Phys Grp, Northfields Ave, Wollongong, NSW 2522, Australia. RI Rosenfeld, Anatoly/D-1989-2014 NR 18 TC 24 Z9 24 U1 0 U2 0 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 USA SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD MAR PY 1999 VL 151 IS 3 BP 235 EP 243 DI 10.2307/3579934 PG 9 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 172NX UT WOS:000078931600001 PM 10073660 ER PT J AU Kennel, SJ Stabin, M Roeske, JC Foote, LJ Lankford, PK Terzaghi-Howe, M Patterson, H Barkenbus, J Popp, DM Boll, R Mirzadeh, S AF Kennel, SJ Stabin, M Roeske, JC Foote, LJ Lankford, PK Terzaghi-Howe, M Patterson, H Barkenbus, J Popp, DM Boll, R Mirzadeh, S TI Radiotoxicity of bismuth-213 bound to membranes of monolayer and spheroid cultures of tumor cells SO RADIATION RESEARCH LA English DT Article ID TRACHEAL EPITHELIAL-CELLS; ALPHA-PARTICLES; MONOCLONAL-ANTIBODY; PRENEOPLASTIC TRANSFORMATION; MULTICELL SPHEROIDS; IN-VITRO; X-RAYS; RADIOIMMUNOTHERAPY; DOSIMETRY; SURVIVAL AB Monoclonal antibody 13A to murine CD44 was used to bind the alpha-particle emitter Bi-213 to cell surfaces of cultured EMT-6 or Line 1 tumor cells, Data on kinetics and saturation of binding, cell shape and nuclear size were used to calculate the absorbed dose to the nuclei, Treatment of monolayer cells with [Bi-213]MAb 13A produced a classical exponential survival curve with no apparent shoulder. Microdosimetry analyses indicated that 1.4-1.7 Gy produced a 37% surviving fraction (D-0), Multicellular spheroids were shown to bind [Bi-213]MAb 13A mainly on the outer cell layer. Relatively small amounts of activity added to the spheroids resulted in relatively large absorbed doses. The result was that 3-6-fold less added radioisotope was necessary to kill similar fractions of cells in spheroids than in monolayer cells. These data are consistent with the interpretation that the a particles from a single Bi-213 atom bound to one cell can penetrate and kill adjacent cells. Flow cytometry was used to sort cells originating from the periphery or from the interior of spheroids. Cells from the outside of the [Bi-213]MAb 13A exposed spheroids had a lower surviving fraction per administered activity than cells from the interior. Cells were killed efficiently in spheroids up to 20-30 cells in diameter. The data support the hypothesis that alpha-particle emitters should be very efficient at killing cells in micrometastases of solid tumors, (C) 1999 by Radiation Research Society. C1 Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. Oak Ridge Inst Sci & Educ, Oak Ridge, TN 37831 USA. Univ Chicago, Chicago, IL 60637 USA. RP Kennel, SJ (reprint author), Oak Ridge Natl Lab, Div Life Sci, Bldg 4500S,MS-6101, Oak Ridge, TN 37831 USA. RI Boll, Rose/C-4138-2016 OI Boll, Rose/0000-0003-2507-4834 NR 46 TC 39 Z9 39 U1 0 U2 1 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 USA SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD MAR PY 1999 VL 151 IS 3 BP 244 EP 256 DI 10.2307/3579935 PG 13 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 172NX UT WOS:000078931600002 PM 10073661 ER PT J AU Jacobson, AR Knox, SO Franz, R Enemark, DC AF Jacobson, AR Knox, SO Franz, R Enemark, DC TI FORTE observations of lightning radio-frequency signatures: Capabilities and basic results SO RADIO SCIENCE LA English DT Article ID TRANSIONOSPHERIC PULSE PAIRS; INTERFEROMETRY; RADIATION AB The FORTE satellite, launched on August 29, 1997, carries both radiofrequency-receiver and optical (imaging and photometric) payloads for the study of lightning. The radio-frequency (RF) data for the first 7 months of operation are described, both to illustrate the satellite's capabilities and to explain the basic statistical findings so far. FORTE's multichannel RF trigger system represents a significant advance in space-based monitoring of lightning emissions. We are able to observe even rather weak and diffuse RF emissions from lightning and are no longer limited to the brightest known events, "transionospheric pulse pairs," or TIPPs. We do see TIPP, and we show that the FORTE observations of TIPPs are consistent only with the second pulse's being due to a ground reflection. We find that TIPPs are basically bimodal in character, one type having a steep roll-off of power from 38 to 130 MHz and the other being essentially flat-spectrum in that range. The steep-spectrum TIPPs cluster together in the manner of most RF emissions from lightning, while the flat-spectrum events tend to maintain a wider spacing (>0.1 s) between recurrent emissions. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87544 USA. RP Jacobson, AR (reprint author), Univ Calif Los Alamos Natl Lab, Mail Stop D466, Los Alamos, NM 87544 USA. NR 12 TC 74 Z9 76 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD MAR-APR PY 1999 VL 34 IS 2 BP 337 EP 354 DI 10.1029/1998RS900043 PG 18 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 180RQ UT WOS:000079399300005 ER PT J AU Baker, KL Porter, JL Ruggles, LE Chrien, RE Idzorek, GC AF Baker, KL Porter, JL Ruggles, LE Chrien, RE Idzorek, GC TI X-ray spectral power measurements utilizing the diffraction pattern of a slit SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID PLASMAS AB An instrument is described which can obtain x-ray spectral power measurements utilizing the diffraction pattern produced when x rays pass through a slit. Traditionally, these types of measurements yielding low to moderate spectral resolution have been made with filtered x-ray diodes or with a transmission grating. The instrument described below has several advantages over filtered x-ray diodes in determining the spectral power profile such as an insensitivity to surface contamination. In addition, this instrument does not require the use of filters which can be destroyed during a shot making absolute measurements difficult and very time consuming. The advantages over a transmission grating system include cost, mechanical robustness, and fewer components which require spectral calibration. (C) 1999 American Institute of Physics. [S0034-6748(99)04303-8]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Baker, KL (reprint author), Univ Calif Davis, Livermore, CA 94551 USA. EM baker7@llnl.gov NR 8 TC 5 Z9 6 U1 1 U2 2 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1999 VL 70 IS 3 BP 1624 EP 1626 DI 10.1063/1.1149642 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 174AN UT WOS:000079012100007 ER PT J AU Carlsten, BE AF Carlsten, BE TI Characterizing the emittance contribution due to rotated quadrupoles and canonical angular momentum using the quadrupole scan technique in electron accelerators SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID PHOTOINJECTORS; INJECTOR; LASER; COMPENSATION; BEAMS AB Standard emittance measurement techniques for bright electron beams are either insensitive to the emittance due to correlated effects like misaligned quadrupoles or a nonzero axial magnetic field at the cathode, or are unable to differentiate that emittance from the beam's intrinsic emittance corresponding to the beam's actual entropy. We describe a technique based on the standard quadrupole scan, in which the beam correlations leading to emittance growth can be directly measured, and the emittance from these correlations can be found for special cases. (C) 1999 American Institute of Physics. [S0034-6748(99)02603-9]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Carlsten, BE (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 20 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1999 VL 70 IS 3 BP 1672 EP 1683 DI 10.1063/1.1149650 PG 12 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 174AN UT WOS:000079012100015 ER PT J AU Britton, CL Clonts, LG Ericson, MN Frank, SS Moore, JA Simpson, ML Young, GR Smith, RS Boissevain, J Hahn, S Kapustinsky, JS Simon-Gillo, J Sullivan, JP van Hecke, H AF Britton, CL Clonts, LG Ericson, MN Frank, SS Moore, JA Simpson, ML Young, GR Smith, RS Boissevain, J Hahn, S Kapustinsky, JS Simon-Gillo, J Sullivan, JP van Hecke, H TI A 32-channel preamplifier chip for the multiplicity vertex detector at PHENIX SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB The TGV32, a 32-channel preamplifier-multiplicity discriminator chip for the multiplicity vertex detector (MVD) at PHENIX, is a unique silicon preamplifier in that it provides both an analog output for storage in an analog memory and a weighted summed-current output for conversion to a channel multiplicity count. The architecture and test results of the chip are presented. Details about the design of the preamplifier, discriminator, and programmable digital-analog converters performance as well as the process variations are presented. The chip is fabricated in a 1.2 mu m, n-well, complementary metal-oxide-semiconductor process. (C) 1999 American Institute of Physics. [S0034-6748(99)04403-2]. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Cadence Design Syst, Cary, NC USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Britton, CL (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Simpson, Michael/A-8410-2011 OI Simpson, Michael/0000-0002-3933-3457 NR 6 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1999 VL 70 IS 3 BP 1684 EP 1687 DI 10.1063/1.1149651 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 174AN UT WOS:000079012100016 ER PT J AU Novick, VJ Johnson, SA Hisgen, HA Reyes, VJ AF Novick, VJ Johnson, SA Hisgen, HA Reyes, VJ TI Real time chemical vapor detection and enhancement utilizing aerosol adsorption SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID IMPACTORS AB A new trace gas detection system, using the high surface area properties of an aerosol to adsorb specific gas species and the high sensitivity and near real time capabilities of the infrared aerosol analyzer, has been successfully demonstrated. A new technique is described that allows certain chemical vapor species to be detected in time frames on the order of 2 min. The technique uses aerosols of selected materials to adsorb the vapor from an air sample, concentrating the vapor onto the surface of the aerosol, then depositing the particles onto a substrate for infrared analysis. For 1 min sample collection times, discernable signals were observed for SO2 levels as low as 2.3 ppm and NH3 concentrations as low as 1.5 ppm. Dimethyl methyl phosphonate (DMMP) vapors from a room temperature container were also detected. Preliminary results indicate that the measured absorbance is a monotonic function of the quantity of the trace gas injected, which gives encouraging evidence that a quantitative determination of the amounts of trace gases present in the atmosphere can be made in many cases. Trace gas detection is dependent upon the aerosol material chosen as the absorbent. For this work, copper (II) chloride and copper (II) sulfate were found to adsorb NH3, SO2, and DMMP. The copper compounds did not absorb NO or NO2. This enables the system to reduce the myriad potential interferences that can exist when sampling the atmosphere. The ammonia complex detected by this technique could be one of many such complexes that can be formed by properly matching the aerosol material and trace gas. As such, the process could be tailored to specific gas/aerosol combinations that could be used to unambiguously identify gaseous effluents of interest. (C) 1999 American Institute of Physics. [S0034-6748(99)03003-8]. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Novick, VJ (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 9 TC 1 Z9 1 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1999 VL 70 IS 3 BP 1829 EP 1834 DI 10.1063/1.1149676 PG 6 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 174AN UT WOS:000079012100042 ER PT J AU Datz, S Drake, GWF Gallagher, TF Kleinpoppen, H Putlitz, GZ AF Datz, S Drake, GWF Gallagher, TF Kleinpoppen, H Putlitz, GZ TI Atomic physics SO REVIEWS OF MODERN PHYSICS LA English DT Review ID HELIUM ISOELECTRONIC SEQUENCE; ELECTRON-IMPACT IONIZATION; ELASTIC-SCATTERING; POLARIZED ELECTRONS; POTASSIUM ATOMS; RYDBERG STATES; EXCITATION; HYDROGEN; COLLISIONS; ENERGIES AB This Section contains examples of important areas in atomic physics, including articles on cold atoms collisions, accelerator-based atomic collisions, fundamental-type atomic collisions, high-precision atomic theory and the few-body problem, and "exotic atoms." [S0034-6861(99)04502-X]. C1 Oak Ridge Natl Lab, Atom Phys Div, Oak Ridge, TN 37831 USA. Univ Windsor, Dept Phys, Windsor, ON N9B 3P4, Canada. Univ Virginia, Dept Phys, Charlottesville, VA 22901 USA. Univ Stirling, Atom Phys Lab, Stirling FK9 4LA, Scotland. Heidelberg Univ, Inst Phys, D-69120 Heidelberg, Germany. RP Oak Ridge Natl Lab, Atom Phys Div, Oak Ridge, TN 37831 USA. NR 119 TC 15 Z9 15 U1 1 U2 11 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0034-6861 EI 1539-0756 J9 REV MOD PHYS JI Rev. Mod. Phys. PD MAR PY 1999 VL 71 IS 2 SI SI BP S223 EP S241 DI 10.1103/RevModPhys.71.S223 PG 19 WC Physics, Multidisciplinary SC Physics GA 172BE UT WOS:000078900800027 ER PT J AU Drell, SD AF Drell, SD TI Physics and US national security SO REVIEWS OF MODERN PHYSICS LA English DT Article ID RECONNAISSANCE AB Throughout history there has been a close relation between physics and the military. In this article the author concentrates on the connection between physics and U.S. national security. In particular he discusses applications of physics to photo reconnaissance from space, antiballistic missile systems, nuclear testing, and scientific advising. The author also touches briefly on ethical aspects of the relation between science and the military. [S0034-6861(99)00402-X]. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Drell, SD (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 21 TC 3 Z9 3 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0034-6861 J9 REV MOD PHYS JI Rev. Mod. Phys. PD MAR PY 1999 VL 71 IS 2 SI SI BP S460 EP S470 DI 10.1103/RevModPhys.71.S460 PG 11 WC Physics, Multidisciplinary SC Physics GA 172BE UT WOS:000078900800055 ER PT J AU Frauenfelder, H Wolynes, PG Austin, RH AF Frauenfelder, H Wolynes, PG Austin, RH TI Biological physics SO REVIEWS OF MODERN PHYSICS LA English DT Article ID OPTICAL-DETECTION; SINGLE MOLECULES; PROTEINS; DNA; MECHANISMS; HEMOGLOBIN; MYOGLOBIN AB Physics and biology have interacted for at least two centuries. In the twentieth century, this interaction has become very strong and the overlap between the two fields has expanded enormously. In the present contribution, the authors sketch where physics has influenced biology and where investigations on biological systems have led to new physical insights. [S0034-6861(99)03902-1]. C1 Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. Univ Illinois, Dept Chem, Urbana, IL 61801 USA. Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. RP Frauenfelder, H (reprint author), Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. NR 63 TC 98 Z9 99 U1 0 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0034-6861 J9 REV MOD PHYS JI Rev. Mod. Phys. PD MAR PY 1999 VL 71 IS 2 SI SI BP S419 EP S430 DI 10.1103/RevModPhys.71.S419 PG 12 WC Physics, Multidisciplinary SC Physics GA 172BE UT WOS:000078900800049 ER PT J AU Henley, EM Schiffer, JP AF Henley, EM Schiffer, JP TI Nuclear physics at the end of the century SO REVIEWS OF MODERN PHYSICS LA English DT Article ID ELECTRIC-DIPOLE MOMENT; HIGH ANGULAR-MOMENTUM; PROTONS; SYSTEMS; SEARCH; HG-199 AB Nuclear physics is the branch of physics that deals with the properties and structure of matter on the hadronic level. This article states a current perspective of the field and of some of the issues that are now on its frontiers. [S0034-6861(99)03502-3]. C1 Univ Washington, Dept Phys, Seattle, WA 98195 USA. Univ Washington, Inst Nucl Theory, Seattle, WA 98195 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Chicago, Chicago, IL 60637 USA. RP Univ Washington, Dept Phys, Seattle, WA 98195 USA. NR 44 TC 0 Z9 0 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0034-6861 EI 1539-0756 J9 REV MOD PHYS JI Rev. Mod. Phys. PD MAR PY 1999 VL 71 IS 2 SI SI BP S205 EP S219 DI 10.1103/RevModPhys.71.S205 PG 15 WC Physics, Multidisciplinary SC Physics GA 172BE UT WOS:000078900800025 ER PT J AU Panofsky, WKH Breidenbach, M AF Panofsky, WKH Breidenbach, M TI Accelerators and detectors SO REVIEWS OF MODERN PHYSICS LA English DT Article C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Panofsky, WKH (reprint author), Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 35 TC 6 Z9 6 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0034-6861 J9 REV MOD PHYS JI Rev. Mod. Phys. PD MAR PY 1999 VL 71 IS 2 SI SI BP S121 EP S132 DI 10.1103/RevModPhys.71.S121 PG 12 WC Physics, Multidisciplinary SC Physics GA 172BE UT WOS:000078900800016 ER PT J AU Sadoulet, B AF Sadoulet, B TI Deciphering the nature of dark matter SO REVIEWS OF MODERN PHYSICS LA English DT Article ID CANDIDATES C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Particle Astrophys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RP Sadoulet, B (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Particle Astrophys, Berkeley, CA 94720 USA. NR 27 TC 18 Z9 18 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0034-6861 J9 REV MOD PHYS JI Rev. Mod. Phys. PD MAR PY 1999 VL 71 IS 2 SI SI BP S197 EP S204 DI 10.1103/RevModPhys.71.S197 PG 8 WC Physics, Multidisciplinary SC Physics GA 172BE UT WOS:000078900800024 ER PT J AU Till, CE AF Till, CE TI Nuclear fission reactors SO REVIEWS OF MODERN PHYSICS LA English DT Article C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Till, CE (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 0 TC 1 Z9 1 U1 1 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0034-6861 J9 REV MOD PHYS JI Rev. Mod. Phys. PD MAR PY 1999 VL 71 IS 2 SI SI BP S451 EP S455 DI 10.1103/RevModPhys.71.S451 PG 5 WC Physics, Multidisciplinary SC Physics GA 172BE UT WOS:000078900800053 ER PT J AU Turner, MS Tyson, JA AF Turner, MS Tyson, JA TI Cosmology at the millennium SO REVIEWS OF MODERN PHYSICS LA English DT Article ID COLD DARK-MATTER; INFLATIONARY UNIVERSE SCENARIO; REDSHIFT SURVEY; LIGHT-CURVE; CONSTANT; FLUCTUATIONS; PERTURBATIONS; TEMPERATURE; GALAXIES; SPECTRUM AB One hundred years ago we did not know how stars generate energy, the age of the Universe was thought to be only millions of years, and our Milky Way galaxy was the only galaxy known. Today, we know that we live in an evolving and expanding universe comprising billions of galaxies, all held together by dark matter. With the hot big-bang model we can trace the evolution of the Universe from the hot soup of quarks and leptons that existed a fraction of a second after the beginning, to the formation of galaxies a few billion years later, and finally to the Universe we see today 13 billion years after the big bang, with its clusters of galaxies, superclusters, voids, and great walls. The attractive force of gravity acting on tiny primeval inhomogeneities in the distribution of matter gave rise to all the structure seen today. A paradigm based upon deep connections between cosmology and elementary particle physics-inflation+cold dark matter-holds the promise of extending our understanding to an even more fundamental level and much earlier times, as well as shedding light on the unification of the forces and particles of Nature. As we enter the 21st century, a flood of observations is testing this paradigm. [S0034-6861(99)03102-5]. C1 Univ Chicago, Enrico Fermi Inst, Dept Astron & Astrophys, Chicago, IL 60637 USA. Univ Chicago, Enrico Fermi Inst, Dept Phys, Chicago, IL 60637 USA. Fermi Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. AT&T Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. RP Turner, MS (reprint author), Univ Chicago, Enrico Fermi Inst, Dept Astron & Astrophys, Chicago, IL 60637 USA. NR 75 TC 44 Z9 45 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0034-6861 J9 REV MOD PHYS JI Rev. Mod. Phys. PD MAR PY 1999 VL 71 IS 2 SI SI BP S145 EP S164 DI 10.1103/RevModPhys.71.S145 PG 20 WC Physics, Multidisciplinary SC Physics GA 172BE UT WOS:000078900800019 ER PT J AU Hawley, ME Brown, GW Kwon, C AF Hawley, ME Brown, GW Kwon, C TI Growth related structure-properties in perovskite films SO SCANNING LA English DT Article; Proceedings Paper CT Scanning 99 Conference CY APR 11-14, 1999 CL CHICAGO, ILLINOIS C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87544 USA. RP Hawley, ME (reprint author), Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87544 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FAMS INC PI MAHWAH PA BOX 832, MAHWAH, NJ 07430-0832 USA SN 0161-0457 J9 SCANNING JI Scanning PD MAR-APR PY 1999 VL 21 IS 2 BP 78 EP 78 PG 1 WC Instruments & Instrumentation; Microscopy SC Instruments & Instrumentation; Microscopy GA 211QG UT WOS:000081171200034 ER PT J AU Pennycook, SJ Kim, M Browning, ND Sohlberg, K Buczko, R Pantelides, ST AF Pennycook, SJ Kim, M Browning, ND Sohlberg, K Buczko, R Pantelides, ST TI Probing the origin of interfacial properties by scanning tunneling electron microscopy SO SCANNING LA English DT Article; Proceedings Paper CT Scanning 99 Conference CY APR 11-14, 1999 CL CHICAGO, IL ID GRAIN-BOUNDARY C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. Univ Illinois, Dept Phys, Chicago, IL 60680 USA. RP Pennycook, SJ (reprint author), Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RI Kim, Miyoung/C-8316-2012 NR 5 TC 0 Z9 0 U1 0 U2 2 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0161-0457 J9 SCANNING JI Scanning PD MAR-APR PY 1999 VL 21 IS 2 BP 92 EP 93 PG 2 WC Instruments & Instrumentation; Microscopy SC Instruments & Instrumentation; Microscopy GA 211QG UT WOS:000081171200051 ER PT J AU Joy, DC Khanna, N Braski, D AF Joy, DC Khanna, N Braski, D TI Secondary electron spectroscopy SO SCANNING LA English DT Article; Proceedings Paper CT Scanning 99 Conference CY APR 11-14, 1999 CL CHICAGO, ILLINOIS C1 Univ Tennessee, EM Facil, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Oak Ridge, TN USA. RP Joy, DC (reprint author), Univ Tennessee, EM Facil, Knoxville, TN 37996 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU FAMS INC PI MAHWAH PA BOX 832, MAHWAH, NJ 07430-0832 USA SN 0161-0457 J9 SCANNING JI Scanning PD MAR-APR PY 1999 VL 21 IS 2 BP 145 EP 145 PG 1 WC Instruments & Instrumentation; Microscopy SC Instruments & Instrumentation; Microscopy GA 211QG UT WOS:000081171200114 ER PT J AU Perelson, AS Nelson, PW AF Perelson, AS Nelson, PW TI Mathematical analysis of HIV-1 dynamics in vivo SO SIAM REVIEW LA English DT Article DE AIDS; mathematical modeling; HIV ID HUMAN-IMMUNODEFICIENCY-VIRUS; IMMUNE-SYSTEM RETROVIRUS; DRUG-RESISTANCE; IN-VIVO; ANTIRETROVIRAL THERAPY; REVERSE-TRANSCRIPTASE; POPULATION-DYNAMICS; DIVERSITY THRESHOLD; DENDRITIC CELLS; RAPID TURNOVER AB Mathematical models have proven valuable in understanding the dynamics of HIV-1 infection in vivo. By comparing these models to data obtained from patients undergoing antiretroviral drug therapy, it has been possible to determine many quantitative features of the interaction between HIV-1, the virus that causes AIDS, and the cells that are infected by the virus. The most dramatic finding has been that even though AIDS is a disease that occurs on a time scale of about 10 years, there are very rapid dynamical processes that occur on time scales of hours to days, as well as slower processes that occur on time scales of weeks to months. We show how dynamical modeling and parameter estimation techniques have uncovered these important features of HIV pathogenesis and impacted the way in which AIDS patients are treated with potent antiretroviral drugs. C1 Univ Calif Los Alamos Natl Lab, Theoret Biol & Biophys Grp, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Div Theoret, Los Alamos, NM 87545 USA. RP Perelson, AS (reprint author), Univ Calif Los Alamos Natl Lab, Theoret Biol & Biophys Grp, POB 1663, Los Alamos, NM 87545 USA. EM asp@receptor.lanl.gov; pnelson@ima.umn.edu NR 69 TC 648 Z9 690 U1 9 U2 41 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 0036-1445 J9 SIAM REV JI SIAM Rev. PD MAR PY 1999 VL 41 IS 1 BP 3 EP 44 DI 10.1137/S0036144598335107 PG 42 WC Mathematics, Applied SC Mathematics GA 183ML UT WOS:000079557300001 ER PT J AU Czyzyk, J Wisniewski, T Wright, SJ AF Czyzyk, J Wisniewski, T Wright, SJ TI Optimization case studies in the NEOS Guide SO SIAM REVIEW LA English DT Article DE World Wide Web; optimization AB We describe several of the case studies in the NEOS Guide, a site oil the World Wide Web that contains informational and educational material about optimization. These studies show how optimization relates to practical applications. They guide the user through relevant details of the application, formulation, solution. and interpretation of thc results. The studies use interactivity to build intuition, allowing users to define their own problems and examine the corresponding solutions. The studies can Le used fur assignments in optimization and operations research courses and as small self-guided units: equivalent to one or two lecture classes. C1 Wroclawska Szkola Jezykowa, PL-54217 Wroclaw, Poland. Argonne Natl Lab, Optimizat Technol Ctr, Argonne, IL 60439 USA. Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. RP Czyzyk, J (reprint author), Wroclawska Szkola Jezykowa, Ul Klodnicka 2, PL-54217 Wroclaw, Poland. EM czyzyk@mcs.anl.gov; wright@mcs.anl.gov NR 12 TC 3 Z9 4 U1 2 U2 2 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 0036-1445 J9 SIAM REV JI SIAM Rev. PD MAR PY 1999 VL 41 IS 1 BP 148 EP 163 DI 10.1137/S0036144598334874 PG 16 WC Mathematics, Applied SC Mathematics GA 183ML UT WOS:000079557300011 ER PT J AU Oumi, M Maurice, D Head-Gordon, M AF Oumi, M Maurice, D Head-Gordon, M TI Ab initio calculations of the absorption spectrum of chalcone SO SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY LA English DT Article DE ab initio; chalcone; attachment-detachment density analysis ID EXCITED-STATES; CONFIGURATION-INTERACTION; SINGLE SUBSTITUTIONS; TRANSMISSION AB The excitation energies and excited states of trans-chalcone (trans-(s-cis)-1,3-diphenylpropenone), and several related molecules (trans-(s-cis)-3-phenylpropenal, s-cis-1-phenylpropenone, propenal, trans-(s-cis)-1-(4-hydroxyphenyl)-3-phenylpropenone, trans-(s-cis)3-(4-hydroxyphenyl)-1-phenyl) have been calculated using single reference ab initio molecular orbital methods, and characterized by attachment-detachment density analysis. The results suggest assignments for the lowest three electronic transitions observed experimentally for trans-(s-cis)-chalcone in solution. The extent of localization of the electronic transitions is established by calculations on the excited states of trans-(s-cis)-3-phenylpropenal, s-cis-1-phenylpropenone and propenal, as well as analysis of the chalcone calculations. Contrary to some previous work, none of these excitations are strongly delocalized over the entire molecule. Calculated substituent shifts for the hydroxy chalcones are in qualitative agreement with experimental data, and support the localized interpretation of the main pi-->pi* transition. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Head-Gordon, M (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 35 TC 18 Z9 19 U1 0 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1386-1425 J9 SPECTROCHIM ACTA A JI Spectroc. Acta Pt. A-Molec. Biomolec. Spectr. PD MAR PY 1999 VL 55 IS 3 BP 525 EP 537 DI 10.1016/S1386-1425(98)00260-1 PG 13 WC Spectroscopy SC Spectroscopy GA 174QJ UT WOS:000079045800010 ER PT J AU Lee, TJ Parthiban, S Head-Gordon, M AF Lee, TJ Parthiban, S Head-Gordon, M TI Accurate calculations on excited states: new theories applied to the -X, -XO, and -XO2 (X = Cl and Br) chromophores and implications for stratospheric bromine chemistry SO SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY LA English DT Article DE stratospheric bromine chemistry; chromophores; excited states ID TRIPLE EXCITATION CORRECTIONS; AB-INITIO CHARACTERIZATION; COUPLED-CLUSTER METHODS; PHOTODISSOCIATION DYNAMICS; CROSS-SECTIONS; SINGLE; HOBR; SPECTRUM; ENERGIES; ISOMERS AB Electronic excitation energies are determined using single-reference based theories derived from response equations involving perturbation theory and coupled-cluster theory. These methods are applied to the singlet manifold of excited electronic states of the HClO, HBrO, HOClO, HOBrO, HClO2, and HBrO2 molecules. Vertical excitation energies (VEEs) for the lowest symmetry unique triplet states are also computed using coupled-cluster theory. Both the singlet and triplet coupled-cluster VEEs are found to be in excellent agreement with experiment for HOBr and HOCl. The reliability of the various perturbation theory approaches is assessed by comparison to the linear response coupled-cluster method, and the CIS(D3) approach is found to perform the best, on average. In order to obtain reliable VEEs for these molecules, CIS(D3) is the recommended approach, unless excited state non-dynamical electron correlation is significant, in which case the recently proposed CIS(D-0) technique may perform better, on average. For both the HClO2 and HBrO2 molecules, it is found that the lowest singlet excited electronic state occurs at too high an energy for it to be accessible from solar radiation in the lower stratosphere. The stratospheric chemistry implications of this, especially for bromine chemistry are discussed. It is suggested that YBrO2 molecules may in fact be the only stable stratospheric bromine reservoir species under light conditions. (C) 1999 Elsevier Science B.V. All rights reserved. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Lee, TJ (reprint author), NASA, Ames Res Ctr, MS230-3, Moffett Field, CA 94035 USA. EM tlee@pegasus.arc.nasa.gov RI Lee, Timothy/K-2838-2012 NR 47 TC 18 Z9 18 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1386-1425 J9 SPECTROCHIM ACTA A JI Spectroc. Acta Pt. A-Molec. Biomolec. Spectr. PD MAR PY 1999 VL 55 IS 3 BP 561 EP 574 DI 10.1016/S1386-1425(98)00262-5 PG 14 WC Spectroscopy SC Spectroscopy GA 174QJ UT WOS:000079045800012 ER PT J AU Rugh, SE Zinkernagel, H Cao, TY AF Rugh, SE Zinkernagel, H Cao, TY TI The Casimir effect and the interpretation of the vacuum SO STUDIES IN HISTORY AND PHILOSOPHY OF MODERN PHYSICS LA English DT Article ID FORCE AB The Casimir force between two neutral metallic plates is often considered conclusive evidence for the reality of electromagnetic zero-point fluctuations in 'empty space' (i.e. in absence of any boundaries). However, it is not well known that the Casimir force can be derived from many different points of view. The purpose of this note is to supply a conceptually oriented introduction to a representative set of these different interpretations. The different accounts suggest that the Casimir effect reveals nothing conclusive about the nature of the vacuum. (C) 1999 Published by Elsevier Science Ltd. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Theory, Los Alamos, NM 87545 USA. Univ Copenhagen, Niels Bohr Inst, Ctr Philosophy Nat & Sci Studies, DK-1168 Copenhagen, Denmark. Boston Univ, Dept Philosophy, Boston, MA 02215 USA. RP Rugh, SE (reprint author), Univ Calif Los Alamos Natl Lab, Div Theory, T-6,MS B288, Los Alamos, NM 87545 USA. EM rugh@nbi.dk; zink@nbi.dk; tycao@bu.edu NR 63 TC 9 Z9 9 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1355-2198 J9 STUD HIST PHILOS M P JI Stud. Hist. Philos. Mod. Phys. PD MAR PY 1999 VL 30B IS 1 BP 111 EP 139 DI 10.1016/S1355-2198(98)00034-3 PG 29 WC History & Philosophy Of Science; Physics, Multidisciplinary SC History & Philosophy of Science; Physics GA 178JU UT WOS:000079263200005 ER PT J AU Luban, M Reynolds, JP Luscombe, JH AF Luban, M Reynolds, JP Luscombe, JH TI Variational tight-binding theory of excitons in compositionally modified semiconductor superlattices SO SUPERLATTICES AND MICROSTRUCTURES LA English DT Article DE excitons; semiconductor superlattices; tight-binding model ID BLOCH OSCILLATIONS; ABSORPTION AB We present results for the binding energy of an exciton formed when an electron-hole pair is photoexcited within a single, compositionally modified layer of a semiconductor superlattice, for example by adding a small percentage of In atoms to a single GaAs layer of a GaAs/AlGaAs system. Such a system could serve as the basis. for spatially-selective photoexcitation, a process whereby a laser pulse would create electron-heavy-hole pairs exclusively in the modified layer. We first derive an effective one-dimensional (ID) Hamiltonian for an electron, by averaging the 3D electron-hole Hamiltonian using a one-parameter trial wavefunction, which is dependent on the in-plane relative coordinates, as well as a normalized Wannier orbital for a single hole. The exciton binding energy is then obtained by computing the lowest bound-state energy of the effective 1D electron Hamiltonian in the nearest-neighbor tight-binding approximation. As a demonstration of the effectiveness of our approach, we find that for periodic superlattices our results for the exciton binding energy are in very good agreement both with experiment and the results of other theoretical calculations. (C) 1999 Academic Press. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. USN, Postgrad Sch, Dept Phys, Monterey, CA 93943 USA. RP Luban, M (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 13 TC 0 Z9 1 U1 1 U2 1 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0749-6036 J9 SUPERLATTICE MICROST JI Superlattices Microstruct. PD MAR PY 1999 VL 25 IS 3 BP 493 EP 503 DI 10.1006/spmi.1998.0599 PG 11 WC Physics, Condensed Matter SC Physics GA 178KN UT WOS:000079265000001 ER PT J AU Ganter, J AF Ganter, J TI GNOME SO TECHNOLOGY REVIEW LA English DT Letter C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Ganter, J (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MASS INST TECHNOL PI CAMBRIDGE PA BUILDING W59, CAMBRIDGE, MA 02139 USA SN 0040-1692 J9 TECHNOL REV JI Technol. Rev. PD MAR-APR PY 1999 VL 102 IS 2 BP 15 EP 15 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 169JM UT WOS:000078744700007 ER PT J AU Lopez, S Peiretti, F Morange, P Laouar, A Fossat, C Bonardo, B Huberman, E Juhan-Vague, I Nalbone, G AF Lopez, S Peiretti, F Morange, P Laouar, A Fossat, C Bonardo, B Huberman, E Juhan-Vague, I Nalbone, G TI Activation of plasminogen activator inhibitor-1 synthesis by phorbol esters in human promyelocyte HL-60 - Roles of PKC beta and MAPK p42 SO THROMBOSIS AND HAEMOSTASIS LA English DT Article ID PROTEIN-KINASE-C; LINKED IMMUNOSORBENT-ASSAY; UROKINASE-RECEPTOR CD87; LEUKEMIA-CELLS; GENE-EXPRESSION; INDUCED DIFFERENTIATION; ENDOTHELIAL-CELLS; IN-VITRO; ADHESION; VITRONECTIN AB HL-60 cells treated by PMA develop the monocyte adherent phenotype and synthesize plasminogen activator inhibitor type-1 (PAI-1). We focused our study on the identification of the PMA-activated protein kinase C (PKC) isoform and its downstream transduction pathway activating PAI-1 synthesis. Acquisition of the monocytic phenotype was evidenced by cell adherence (90-95%) and a sharp increase of CD 36 and receptor for urokinase plasminogen activator (uPAR) surface expression. Ro 31-8220, a specific inhibitor of PKC, prevented PMA-induced PAI-1 synthesis (mRNA and protein levels) and cell adhesion. To identify the PKC isoform, we took advantage of the HL-525 cell line, an HL-60 cell variant deficient in PKC beta gene expression. This defect prevents PMA to induce the differentiation process. HL-525 stimulated by PMA did not synthesize PAI-1 nor become adherent. However, in HL-525 cells either pretreated by retinoic acid that reinduces PKC beta gene expression or transfected with PKC beta cDNA, PMA significantly activated PAI-1 synthesis and adhesion of cells. Immunoblotting of active Mitogen Activated Protein Kinase (MAPK) p42/p44 in HL-60 cells showed a preferential and sustained activation of the p42 isoform by PMA over the p44 isoform. Po 31-8220 significantly attenuated this activation. PD 098059 and U0126, both highly specific MEK inhibitors, efficiently prevented PMA-induced PAI-1 synthesis (mRNA and protein levels) and cell adhesion whereas SB203580, a specific inhibitor of stress-activated MAPK p38, did not. Results obtained from HL-60 and HL-525 cells indicate that the PMA-activated transduction pathway of uPAR expression involves a PKC isoform other than PKC beta. In conclusion, we propose that the pathway PKC beta-MEK-MAPK p42 is a potential linear route for PAI-1 synthesis leading to morphological changes and adherence linked to PMA-induced differentiation in HL-60 cells. C1 Fac Med Marseille, Hematol Lab, F-13385 Marseille 5, France. Argonne Natl Lab, Ctr Mechanist Biol & Biotechnol, Argonne, IL 60439 USA. RP Nalbone, G (reprint author), Fac Med Marseille, Hematol Lab, 27 Bd Jean Moulin, F-13385 Marseille 5, France. NR 50 TC 18 Z9 18 U1 0 U2 1 PU F K SCHATTAUER VERLAG GMBH PI STUTTGART PA P O BOX 10 45 43, LENZHALDE 3, D-70040 STUTTGART, GERMANY SN 0340-6245 J9 THROMB HAEMOSTASIS JI Thromb. Haemost. PD MAR PY 1999 VL 81 IS 3 BP 415 EP 422 PG 8 WC Hematology; Peripheral Vascular Disease SC Hematology; Cardiovascular System & Cardiology GA 174UE UT WOS:000079053400017 PM 10102471 ER PT J AU Jager, HI Van Winkle, W Holcomb, BD AF Jager, HI Van Winkle, W Holcomb, BD TI Would hydrologic climate changes in Sierra Nevada streams influence trout persistence? SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Article ID INDIVIDUAL-BASED MODEL; POTENTIAL HABITAT LOSS; RAINBOW-TROUT; SALMO-GAIRDNERI; UNITED-STATES; BROWN TROUT; FISH; GROWTH; TEMPERATURE; CALIFORNIA AB We predicted the consequences of climate change for sympatric populations of brown trout Salmo trutta and rainbow trout Onco,Oncorhynchus mykiss in an upstream and a downstream reach of a Sierra Nevada stream with the help of an individual-based trout population model. The model evaluated the ecological effects of two anticipated responses to climate change: (1) a shift in peak flows from spring to winter and (2) an increase in stream temperature. Changes in temperature and flow regime both influenced simulated persistence of the two trout species. We hypothesized a decrease in the fall-spawning brown trout population as a result of winter hoods that scour brown trout redds. Although scouring mortality showed the expected pattern, effects of seasonal shifts in flow on simulated dewatering of redds was equally important and tended to compensate for scouring. Because trout are coldwater fishes, we hypothesized that a rise in mean stream temperature would be harmful to both species, particularly in downstream reaches. We found that a climate change scenario with a 2 degrees C increase in average stream temperature benefited both species in the cooler upstream reach but was harmful in the warmer downstream reach. Overall, our results supported the hypothesis that climate change will restrict trout to higher elevations in the Sierra Nevada. Finally, the combined effects of elevated temperature and shifted flow differed from the effect of elevated temperature alone. In combination, the two climatic factors produced threshold effects in rainbow trout abundance by shifting the age at first maturation. Complex interactions between the period of incubation and various causes of redd mortality (dewatering, scouring, and temperature-related mortality) also lead to nonadditive effects of the two climatic factors on abundances. We conclude that focusing on one factor alone (i.e., temperature) may not be sufficient to predict climate change effects in the stream environment. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Jager, HI (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. NR 51 TC 38 Z9 39 U1 1 U2 18 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 USA SN 0002-8487 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD MAR PY 1999 VL 128 IS 2 BP 222 EP 240 DI 10.1577/1548-8659(1999)128<0222:WHCCIS>2.0.CO;2 PG 19 WC Fisheries SC Fisheries GA 212JE UT WOS:000081212900002 ER PT J AU Railsback, SF Rose, KA AF Railsback, SF Rose, KA TI Bioenergetics modeling of stream trout growth: Temperature and food consumption effects SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Article ID RAINBOW-TROUT; INVERTEBRATE DRIFT; BROWN TROUT; POPULATION; BROOK; LIMITATION; ENERGETICS; RESPONSES; EXAMPLES; BASS AB We investigated bioenergetics modeling of growth as an approach for assessing the effects of temperature changes on stream dwelling rainbow trout Oncorhynchus mykiss. Study objectives were (1) to determine the relative effect of temperature versus food consumption on model-predicted growth and (2) to identify relationships between model-predicted food consumption and commonly measured environmental variables. A bioenergetics model for rainbow trout was calibrated to apparent age-1 growth in summer and fall-spring periods for 10 years at eight Sierra Nevada, California, study sites. Model analyses showed that the observed year-to-year variation in summer growth was related to food consumption but not to temperature and that temperature was more important, but still of secondary importance, to observed variation in fall-spring growth. Growth at all sampling sites appeared lower and more variable in summer than in other seasons, and variation among sites and years in the food consumption parameter P (determined by fitting the model to observed apparent growth) was highly related to environmental variables during fall-spring but not during summer. During fall-spring, 80% of the variation in P was explained by a linear regression model that included temperature, flow, and trout density. Summer P-values were only weakly related to stream gradient. Our data and analysis indicate that(1) when not extreme, temperatures in summer may have less effect on growth than during other seasons and (2) growth is more affected by factors controlling food consumption (including indirect effects of temperature) than by the direct effects of temperature. C1 Lang Railsback & Associates, Arcata, CA 95521 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Railsback, SF (reprint author), Lang Railsback & Associates, 250 Calif Ave, Arcata, CA 95521 USA. OI Railsback, Steven/0000-0002-5923-9847 NR 37 TC 88 Z9 88 U1 1 U2 28 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 USA SN 0002-8487 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD MAR PY 1999 VL 128 IS 2 BP 241 EP 256 DI 10.1577/1548-8659(1999)128<0241:BMOSTG>2.0.CO;2 PG 16 WC Fisheries SC Fisheries GA 212JE UT WOS:000081212900003 ER PT J AU Plotkin, S AF Plotkin, S TI Technologies and policies for controlling greenhouse gas emissions from the US automobile and light truck fleet SO TRANSPORTATION QUARTERLY LA English DT Article AB The transportation sector produces slightly more than 30% of the greenhouse gas emissions from the United States, with light-duty vehicles-automobiles and light trucks-accounting for more than half of the sector's emissions.(2) This makes the light-duty vehicle fleet an appealing target for carbon emissions reductions undertaken in pursuit of satisfying the United States' potential obligations under the Kyoto protocol. Furthermore, the current Light-duty vehicle fleet is essentially fully dependent on petroleum for its energy supply, so reductions in greenhouse gases will yield similar reductions in U.S. oil use, an attractive proposition to those concerned about U.S. dependence on petroleum imports. Reducing light-duty greenhouse gas emissions and petroleum use can be accomplished by increasing vehicle energy efficiency, shifting travel to more efficient modes, reducing travel overall (by increasing the price of travel, changing development patterns, or other means), changing fuels, and increasing vehicle occupancy. This article focuses on policies and technologies for increasing vehicle energy efficiency, though policies that raise fuel prices will encourage other physical measures, as well. C1 Argonne Natl Lab, Ctr Transportat Res, Argonne, IL 60439 USA. RP Plotkin, S (reprint author), Argonne Natl Lab, Ctr Transportat Res, Argonne, IL 60439 USA. NR 25 TC 1 Z9 1 U1 1 U2 4 PU ENO FOUNDATION TRANSPORT INC PI WASHINGTON PA 1634 I ST NW, STE 500, WASHINGTON, DC 20006-4003 USA SN 0278-9434 J9 TRANSPORT Q JI Transp. Q. PD SPR PY 1999 VL 53 IS 2 BP 7 EP 30 PG 24 WC Transportation SC Transportation GA 199JX UT WOS:000080478500002 ER PT J AU Zoh, KD Daniels, JI Knezovich, JP Stenstrom, MK AF Zoh, KD Daniels, JI Knezovich, JP Stenstrom, MK TI Treatment of hydrolysates of the high explosives hexahydro-1,3,5-trinitro-1,3,5-triazine and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine using biological denitrification SO WATER ENVIRONMENT RESEARCH LA English DT Article DE hydrolysate (hydrolysis byproducts); biological denitrification; hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX); octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX); acetate; formate; formaldehyde; nitrate; nitrite ID ACTIVATED CARBON; KINETICS; WATER; HMX AB Alkaline hydrolysis byproducts of the high explosives hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), consisting of acetate, formate, formaldehyde, and nitrite, were treated in a denitrifying (anoxic) packed-bed upflow reactor. Additional nitrite or nitrate was added to match the carbon oxidation requirement, in a 2-year study, more than 90% removal of the organic compounds and nitrite were observed in a reactor with a 3-hour retention time. Removal was quantified by measuring actual compound concentrations and total organic carbon. The stoichiometry of the experimental results closely matched the predicted stoichiometry. Formaldehyde and acetate were preferentially removed over formate. The system removed N (nitrite):C (acetate):C (formaldehyde):C (formate) in a relative ratio of 1:0.07:0.36:0.50, respectively. The volumetric removal rare was as high as 170 mg/L of nitrite-nitrogen per day with existing carbon sources. The observed cell yield (mass basis) of nitrite reduction with acetate/formate was 0.21 mg cells/mg total organic carbon or 0.16 mg cells/mg chemical oxygen demand at 20 degrees C. This culture was also capable of biodegrading RDX and HMX when using nitrate as an electron acceptor. C1 Univ Calif Los Angeles, Dept Civil & Environm Engn, Los Angeles, CA 90095 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. RP Stenstrom, MK (reprint author), Univ Calif Los Angeles, Dept Civil & Environm Engn, Los Angeles, CA 90095 USA. RI Stenstrom, Michael/A-3177-2008 OI Stenstrom, Michael/0000-0001-6157-0718 NR 20 TC 15 Z9 16 U1 1 U2 6 PU WATER ENVIRONMENT FEDERATION PI ALEXANDRIA PA 601 WYTHE ST, ALEXANDRIA, VA 22314-1994 USA SN 1061-4303 J9 WATER ENVIRON RES JI Water Environ. Res. PD MAR-APR PY 1999 VL 71 IS 2 BP 148 EP 155 DI 10.2175/106143099X121490 PG 8 WC Engineering, Environmental; Environmental Sciences; Limnology; Water Resources SC Engineering; Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 183GZ UT WOS:000079547000004 ER PT J AU Sanchez-Vila, X Axness, CL Carrera, J AF Sanchez-Vila, X Axness, CL Carrera, J TI Upscaling transmissivity under radially convergent flow in heterogeneous media SO WATER RESOURCES RESEARCH LA English DT Article ID POROUS-MEDIA; HYDRAULIC CONDUCTIVITY; PERMEABILITY; WELL AB Most field methods used to estimate transmissivity values rely on the analysis of drawdown under convergent flow conditions. For a single well in a homogeneous and isotropic aquifer and under steady state flow conditions, drawdown s is directly related to the pumping rate Q through transmissivity T. In real, nonhomogeneous aquifers, s and Q are still directly related, now through a value called equivalent transmissivity T In this context, T-eq is defined as the value thar best fits Thiem's equation and would, for example, be the transmissivity assigned to the well location in the classical interpretation of a steady state pumping test. This equivalent or upscaled transmissivity is clearly not a local value but is some representative value of a certain area surrounding the well. In this paper we present an analytical solution for upscaling transmissivities under radially convergent steady state flow conditions produced by constant pumping from a well of radius r(W) in a heterogeneous aquifer based upon an extension of Thiem's equation. Using a perturbation expansion, we derive a second-order expression for T-eq given as a weighted average of the fluctuations in log T throughout the domain. This expression is compared to other averaging formulae from the literature, and differences are pointed out. T depends upon an infinite series which may be expressed in terms of coefficients of the finite Fourier transform of the log transmissivity function. Sufficient conditions for convergence of this series are examined. Finally, we show that our solution agrees with existing analytical ones to second order and test the solution with a numerical example. C1 Univ Politecn Catalunya, Dept Enginyeria Terreny & Cartog, ES-08034 Barcelona, Spain. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Sanchez-Vila, X (reprint author), Univ Politecn Catalunya, Dept Enginyeria Terreny & Cartog, ES-08034 Barcelona, Spain. RI Carrera, Jesus/E-7251-2011; OI Sanchez-Vila, Xavier/0000-0002-1234-9897 NR 20 TC 31 Z9 31 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD MAR PY 1999 VL 35 IS 3 BP 613 EP 621 DI 10.1029/1998WR900056 PG 9 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 169WG UT WOS:000078771700001 ER PT J AU Tartakovsky, DM Neuman, SP Lu, ZM AF Tartakovsky, DM Neuman, SP Lu, ZM TI Conditional stochastic averaging of steady state unsaturated flow by means of Kirchhoff transformation SO WATER RESOURCES RESEARCH LA English DT Article ID SOIL HYDRAULIC-PROPERTIES; WATER TRANSPORT PARAMETERS; IN-SITU MEASUREMENTS; HETEROGENEOUS SOILS; GEOSTATISTICAL APPROACH; SPATIAL VARIABILITY; ALPHA-PARAMETER; POROUS-MEDIA; CONDUCTIVITY; APPROXIMATION AB We consider the effect of measuring randomly varying soil hydraulic properties on one's ability to predict steady state unsaturated flow subject to random sources and/or initial and boundary conditions. Our aim is to allow optimum unbiased prediction of system states (pressure head, water content) and fluxes deterministically, without upscaling and without linearizing the constitutive characteristics of the soil. It has been shown by Neuman et nl. [1999] that such prediction is possible by means of first ensemble moments of system states and fluxes, conditioned on measured values of soil properties, when the latter scale in a linearly separable fashion as proposed by Vogel et al. [1991]; the uncertainty associated with such predictions can be quantified by means of the corresponding conditional second moments. The derivation of moment equations for soils whose properties do not scale in the above manner requires linearizing the corresponding constitutive relations, which may lead to major inaccuracies when these relations are highly nonlinear, as is often the case in nature. When the scaling parameter of pressure head is a random variable independent of location, the steady state unsaturated flow equation can be linearized by means of the Kirchhoff transformation for gravity-free flow. Linearization is also possible in the presence of gravity when hydraulic conductivity varies exponentially with pressure head. For the latter case we develop exact conditional first- and second-moment equations which are nonlocal and therefore non-Darcian. We solve these equations analytically by perturbation for unconditional vertical infiltration and compare our solution with the results of numerical Monte Carlo simulations. Our analytical solution demonstrates in a rigorous manner that the concept of effective hydraulic conductivity does not apply to ensemble-averaged unsaturated flow except when gravity is the sole driving force. C1 Univ Calif Los Alamos Natl Lab, Div Earth & Environm Sci, Geoanal Grp, Los Alamos, NM 87545 USA. Univ Arizona, Dept Hydrol & Water Resources, Tucson, AZ 85721 USA. RP Tartakovsky, DM (reprint author), Univ Calif Los Alamos Natl Lab, Div Earth & Environm Sci, Geoanal Grp, EES-5,MS C306, Los Alamos, NM 87545 USA. RI Tartakovsky, Daniel/E-7694-2013; OI Lu, Zhiming/0000-0001-5800-3368 NR 45 TC 53 Z9 53 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD MAR PY 1999 VL 35 IS 3 BP 731 EP 745 DI 10.1029/1998WR900092 PG 15 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 169WG UT WOS:000078771700011 ER PT J AU Abdallah, J Palmer, N Gekelman, W Maggs, J Clark, REH AF Abdallah, J Palmer, N Gekelman, W Maggs, J Clark, REH TI Time-dependent kinetics model for a helium discharge plasma SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID DIFFERENTIAL CROSS-SECTIONS; ELECTRON-IMPACT EXCITATION; IONIZATION; DEVICE AB Measurements of electron density and electron temperature at various times during a cathode discharge in helium have been recorded with a Langmuir probe in the UCLA large plasma device. The measured electron temperatures were then used in a time-dependent collisional-radiative model to propagate the electron density as a function of time for plasma conditions corresponding to population densities far from equilibrium. The initial gas density was extracted from pressure measurements and used in the calculations so there were no adjustable parameters in the model. The calculated and measured densities are in good agreement for three different radial positions in the plasma. The results show that the plasma formation becomes dominated by bulk thermal electrons early in the discharge. The detailed model is compared with several simplified models to study the role of metastable levels and excited states in the plasma kinetics. The relative importance of the various atomic processes in the calculation of plasma formation is also discussed. C1 Univ Calif Los Angeles, Dept Phys, Los Angeles, CA 90095 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Abdallah, J (reprint author), Univ Calif Los Angeles, Dept Phys, Los Angeles, CA 90095 USA. NR 14 TC 2 Z9 2 U1 1 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD FEB 28 PY 1999 VL 32 IS 4 BP 1001 EP 1008 DI 10.1088/0953-4075/32/4/015 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 175LR UT WOS:000079096400015 ER PT J AU Shlyaptseva, AS Mancini, RC Neill, P Beiersdorfer, P AF Shlyaptseva, AS Mancini, RC Neill, P Beiersdorfer, P TI Polarization properties of dielectronic satellite lines in the K-shell x-ray spectra of B-like Fe XXII SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID BORON ISOELECTRONIC SEQUENCE; ELECTRON-BEAM; IONS; TRANSITIONS; EXCITATION; AUGER; RATES; XXV AB We report the results of a combined theoretical and experimental study of B-like dielectronic recombination satellite lines excited by an electron beam. Polarization sensitive spectra were accumulated at the Lawrence Livermore electron beam ion trap facility. Three beam energies were chosen in the region of maximum B-like Pe satellite emission. At each energy, spectra were obtained using two LiF crystals of differing polarization sensitivities. Polarization-dependent spectra have been calculated using the degree of polarization of single lines computed with a photon density matrix formalism. The agreement between the experiment and theory is very good. Two spectral features were observed to have polarizations that were particularly sensitive to the electron beam energy. Spectral features with this property are candidates as diagnostics of energy and direction of electron beams in plasmas. C1 Univ Nevada, Dept Phys, Reno, NV 89557 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Shlyaptseva, AS (reprint author), Univ Nevada, Dept Phys, Reno, NV 89557 USA. NR 15 TC 15 Z9 16 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD FEB 28 PY 1999 VL 32 IS 4 BP 1041 EP 1051 DI 10.1088/0953-4075/32/4/019 PG 11 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 175LR UT WOS:000079096400019 ER PT J AU Smith, DA Shao, XM Holden, DN Rhodes, CT Brook, M Krehbiel, PR Stanley, M Rison, W Thomas, RJ AF Smith, DA Shao, XM Holden, DN Rhodes, CT Brook, M Krehbiel, PR Stanley, M Rison, W Thomas, RJ TI A distinct class of isolated intracloud lightning discharges and their associated radio emissions SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TRANSIONOSPHERIC PULSE PAIRS; ELECTRIC-FIELD PULSES; RADIATION-FIELDS; STEPPED LEADERS; CLOUD FLASHES; THUNDERSTORMS; ELECTRIFICATION; PICTURES; FLORIDA AB Observations of radio emissions from thunderstorms were made during the summer of 1996 using two arrays of sensors located in northern New Mexico, The first array consisted of three fast electric field change meters separated by distances of 30 to 230 km. The second array consisted of three broadband (3 to 30 MHz) HF data acquisition systems separated by distances of 6 to 13 km. Differences in signal times of arrival at multiple stations were used to locate the sources of received signals. Relative times of arrival of signal reflections from the ionosphere and Earth were used to determine source heights. A distinct class of short-duration electric field change emissions was identified and characterized. The emissions have previously been termed narrow positive bipolar pulses (NPBPs). NPBPs were emitted from singular intracloud discharges that occurred in the most active regions of three thunderstorms located in New Mexico and west Texas. The discharges occurred at altitudes between 8 and 11 km above mean sea level. NEXRAD radar images show that the NPBP sources were located in close proximity to high reflectivity storm cores where reflectivity values were in excess of 40 dBZ. NPBP electric field change waveforms were isolated, bipolar, initially positive pulses with peak amplitudes comparable to those of return stroke field change waveforms. The mean FWHM (full width at half maximum) of initial NPBP field change pulses was 4.7 mu s The HF emissions associated with NPBPs were broadband noise-like radiation bursts with a mean duration of 2.8 mu s and amplitudes 10 times larger than emissions from typical intracloud and cloud-to-ground lightning processes. Calculations indicate that the events represent a distinct class of singular, isolated lightning discharges that have limited spatial extents of 300 to 1000 m and occur in high electric field regions. The unique radio emissions produced by these discharges, in combination with their unprecedented physical characteristics, clearly distinguish the events from other types of previously observed thunderstorm electrical processes. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. New Mexico Inst Min & Technol, Geophys Res Ctr, Langmuir Lab Atmospher Res, Socorro, NM 87801 USA. RP Smith, DA (reprint author), Los Alamos Natl Lab, NIS-1,MS D466, Los Alamos, NM 87545 USA. EM smithda@lanl.gov NR 76 TC 127 Z9 137 U1 1 U2 8 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 FEB 27 PY 1999 VL 104 IS D4 BP 4189 EP 4212 DI 10.1029/1998JD200045 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 169TF UT WOS:000078764100024 ER PT J AU Beck, KM Sasaki, T Koshizaki, N AF Beck, KM Sasaki, T Koshizaki, N TI Characterization of nanocomposite materials prepared via laser ablation of Pt/TiO2 bi-combinant targets SO CHEMICAL PHYSICS LETTERS LA English DT Article ID PHOTOCATALYTIC DECOMPOSITION; OPTICAL-PROPERTIES; TIO2; ANATASE; FILMS AB Pt/TiO2 thin-film nanocomposites have been prepared using a process of bi-combinant-target pulsed-laser deposition. Pt nanoparticles have been produced, possibly in the deposition process through rapid surface diffusion. The nanocomposite films can be created with the anatase form of TiO2 being the dominant crystal structure. The Pt nanoparticles are similar to 30 nm in size and homogeneously distributed. Within the nanocomposite films, a similar to 5% Pt atomic concentration can be synthesized from 20% Pt by weight bi-combinant targets. These thin films exhibit an optical bandgap less than 2.3 eV and a photoluminescence emission between 680 and 800 nm. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Pacific NW Lab, William R Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. Agcy Ind Sci & Technol, Natl Inst Mat & Chem Res, Tsukuba, Ibaraki 3058565, Japan. RP Beck, KM (reprint author), Pacific NW Lab, William R Wiley Environm Mol Sci Lab, K8-88, Richland, WA 99352 USA. RI Koshizaki, Naoto/E-2024-2011 NR 17 TC 16 Z9 16 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD FEB 26 PY 1999 VL 301 IS 3-4 BP 336 EP 342 DI 10.1016/S0009-2614(99)00022-6 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 170AE UT WOS:000078782300020 ER PT J AU Ahmed, M Peterka, DS Suits, AG AF Ahmed, M Peterka, DS Suits, AG TI Crossed-beam reaction of O(D-1)+D-2 -> OD+D by velocity map imaging SO CHEMICAL PHYSICS LETTERS LA English DT Article ID STATE-RESOLVED STEREODYNAMICS; SCATTERING; SECTIONS; SURFACE; H2O; DISTRIBUTIONS; INSERTION; AR AB The technique of velocity map imaging [Eppink and Parker, Rev. Sci. Instrum. 68 (1997) 3477] has been applied to the reaction O(D-1) + D-2 --> OD + D under single-collision conditions in crossed molecular beams at a collision energy (E-coll) of 2.4 kcal/mol. Images of the reactively scattered D-atom product were recorded, yielding the full double differential cross-sections (energy and angle) for the reaction. The translational energy and angular distributions are observed to be strongly coupled, with the forward-scattered products showing the largest translational energy release and the sideways-scattered products the lowest translational energy release. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Ernest Orlando Lawrence Berkeley Natl Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Suits, AG (reprint author), Ernest Orlando Lawrence Berkeley Natl Lab, Div Chem Sci, Berkeley, CA 94720 USA. RI Ahmed, Musahid/A-8733-2009 NR 28 TC 61 Z9 61 U1 2 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD FEB 26 PY 1999 VL 301 IS 3-4 BP 372 EP 378 DI 10.1016/S0009-2614(99)00048-2 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 170AE UT WOS:000078782300025 ER PT J AU Nayak, SK Rao, BK Jena, P Li, X Wang, LS AF Nayak, SK Rao, BK Jena, P Li, X Wang, LS TI Observation of a spin-protected high-energy isomer of Al4N- cluster SO CHEMICAL PHYSICS LETTERS LA English DT Article ID PHOTOELECTRON-SPECTROSCOPY; LI-4(-) AB Photoelectron spectroscopy experiments combined with first-principles calculations based on generalized gradient approximation to the density functional theory show that an Al4N- anion cluster lying 0.97 eV above its ground-state structure can exist not because it is protected by an energy barrier but because it has a different spin multiplicity. Its existence is established by comparing the calculated vertical electron detachment energies with the experimental photo-detachment spectra. The electron affinity of Al3N, on the other hand, is anomalously low showing the characteristic of a closed-shell molecule and providing the signature of a monovalent Al, (C) 1999 Elsevier Science B.V. All rights reserved. C1 Virginia Commonwealth Univ, Dept Phys, Richmond, VA 23284 USA. Washington State Univ, Dept Phys, Richland, WA 99352 USA. Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Rao, BK (reprint author), Virginia Commonwealth Univ, Dept Phys, Richmond, VA 23284 USA. NR 17 TC 34 Z9 34 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD FEB 26 PY 1999 VL 301 IS 3-4 BP 379 EP 384 DI 10.1016/S0009-2614(99)00024-X PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 170AE UT WOS:000078782300026 ER PT J AU Taylor, TR Bise, RT Asmis, KR Neumark, DM AF Taylor, TR Bise, RT Asmis, KR Neumark, DM TI The singlet-triplet splittings of NCN SO CHEMICAL PHYSICS LETTERS LA English DT Article ID ULTRAVIOLET PHOTOELECTRON-SPECTROSCOPY; AB-INITIO; HOT-BAND; TRANSITION; MOLECULES; STATES; ANION; CCO AB The photoelectron spectrum of the cyanonitrene anion, NCN-, has been measured at 416 and 266 nm. The 266 nm spectrum reveals the (a) over tilde (1)Delta(g) and the (b) over tilde (1)Sigma(g)(+) states together with the (X) over tilde (3)Sigma(g)(-), ground state for the first time. These low-lying singlet states are separated from the triplet ground state by 1.010 +/- 0.010 and 1.629 +/- 0.010 eV, respectively. We find a vibrational frequency of 1120 +/- 50 cm(-1) for the nu(1) mode of the (b) over tilde (1)Sigma(g)(+) state. The ions were produced in a new source particularly suitable for anion precursors with low vapor pressure. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. EM dan@radon.cchem.berkeley.edu RI Asmis, Knut/N-5408-2014; Neumark, Daniel/B-9551-2009 OI Asmis, Knut/0000-0001-6297-5856; Neumark, Daniel/0000-0002-3762-9473 NR 31 TC 21 Z9 21 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 EI 1873-4448 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD FEB 26 PY 1999 VL 301 IS 3-4 BP 413 EP 416 DI 10.1016/S0009-2614(99)00053-6 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 170AE UT WOS:000078782300032 ER PT J AU Chi, YI Martinez-Cruz, LA Jancarik, J Swanson, RV Robertson, DE Kim, SH AF Chi, YI Martinez-Cruz, LA Jancarik, J Swanson, RV Robertson, DE Kim, SH TI Crystal structure of the beta-glycosidase from the hyperthermophile Thermosphaera aggregans: insights into its activity and thermostability SO FEBS LETTERS LA English DT Article DE beta-glycosidase; crystal structure; glycosyl hydrolase; hyperthermophile; thermostability ID GLYCOSYL HYDROLASES; SULFOLOBUS-SOLFATARICUS; 3-DIMENSIONAL STRUCTURE; PYROCOCCUS-FURIOSUS; ANGSTROM RESOLUTION; GLUCOSIDASE; PROTEIN; DEHYDROGENASE; MYROSINASE; CLASSIFICATION AB The glycosyl hydrolases are an important group of enzymes that are responsible for cleaving a range of biologically significant carbohydrate compounds. Structural information on these enzymes has provided useful information on their molecular basis for the functional variations, while the characterization of the structural features that account for the high thermostability of proteins is of great scientific and biotechnological interest. To these ends we have determined the crystal structure of the beta-glycosidase from a hyperthermophilic archeon Thermosphaera a aggregans. The structure is a (beta/alpha)(8) barrel (TIM-barrel), as seen in other glycosyl hydrolase family 1 members, and forms a tetramer. Inspection of the active site and the surrounding area reveals two catalytic glutamate residues consistent with the retaining mechanism and the surrounding polar and aromatic residues consistent with a monosaccharide binding site. Comparison of this structure with its mesophilic counterparts implicates a variety of structural features that could contribute to the thermostability. These include an increased number of surface ion pairs, an increased number of internal water molecules and a decreased surface area upon forming an oligomeric quaternary structure. (C) 1999 Federation of European Biochemical Societies. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Diversa Corp, San Diego, CA 92121 USA. RP Kim, SH (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. EM shkim@lbl.gov RI Martinez-Cruz, Luis Alfonso/G-2285-2011; OI Martinez-Cruz, Luis Alfonso/0000-0002-5856-9377; Swanson, Ronald/0000-0002-6486-2676 NR 43 TC 55 Z9 59 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0014-5793 J9 FEBS LETT JI FEBS Lett. PD FEB 26 PY 1999 VL 445 IS 2-3 BP 375 EP 383 DI 10.1016/S0014-5793(99)00090-3 PG 9 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 175YC UT WOS:000079122800033 PM 10094493 ER PT J AU Petersen, SL Ballou, NE AF Petersen, SL Ballou, NE TI Separation of micrometer-size oxide particles by capillary zone electrophoresis SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE buffer composition; metal oxides ID COLLOIDAL PARTICLES; ELECTROLYTE AB High quality separations of three-component mixtures of suspended micrometer-size metal oxide particles have been achieved by capillary zone electrophoresis in two different high-pH aqueous buffer systems. Mixtures of Al2O3, Fe3O4 and TiO2 and of Al2O3, Fe3O4 and Fe2O3 were separated in 5-10 min in either carbonate buffer, pH 10.6 or pyrophosphate buffer, pH 10.2. The effects of electric field strength, buffer concentration and buffer type on separation quality were determined. Under optimized conditions, the separations were nearly baseline resolved. Complete separation of a mixture of Al2O3 and UO2 particles was also accomplished. Different sized particles/aggregates of a given oxide were found to co-migrate so that, for the systems studied, particle size effects were negligible and the separations were electrophoretic in nature. Reproducibilities of migration times and peak widths, heights and shapes were found to be excellent, with relative standard deviations of migration times consistently being <1%. Published by Elsevier Science B.V. C1 Pacific NW Lab, Environm & Hlth Sci Div, Richland, WA 99352 USA. RP Petersen, SL (reprint author), Pacific NW Lab, Environm & Hlth Sci Div, POB 999,Mailstop P7-07, Richland, WA 99352 USA. EM steven.petersen@pnl.gov NR 18 TC 32 Z9 35 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD FEB 26 PY 1999 VL 834 IS 1-2 BP 445 EP 452 DI 10.1016/S0021-9673(98)00864-4 PG 8 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 174VD UT WOS:000079055900029 ER PT J AU Clayton, DD Liu, WH Dalgarno, A AF Clayton, DD Liu, WH Dalgarno, A TI Condensation of carbon in radioactive supernova gas SO SCIENCE LA English DT Article ID RADIATIVE ASSOCIATION; INTERSTELLAR CLOUDS; MURCHISON METEORITE; LARGE HYDROCARBONS; PRESOLAR GRAPHITE; CLUSTERS; MATTER; ORIGIN; GRAINS AB Chemistry resulting in the formation of Large carbon-bearing molecules and dust in the interior of an expanding supernova was explored, and the equations governing their abundances were solved numerically, Carbon dust condenses from initially gaseous carbon and oxygen atoms because energetic electrons produced by radioactivity in the supernova cause dissociation of the carbon monoxide molecules, which would otherwise form and Limit the supply of carbon atoms, The resulting free carbon atoms enable carbon dust to grow faster by carbon association than the rate at which the dust can be destroyed by oxidation. The origin of presolar micrometer-sized carbon solids that are found in meteorites is thereby altered. C1 Clemson Univ, Dept Phys & Astron, Clemson, SC 29634 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Clayton, DD (reprint author), Clemson Univ, Dept Phys & Astron, Clemson, SC 29634 USA. NR 34 TC 91 Z9 91 U1 1 U2 10 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 FEB 26 PY 1999 VL 283 IS 5406 BP 1290 EP 1292 DI 10.1126/science.283.5406.1290 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 171AM UT WOS:000078839900030 PM 10037591 ER PT J AU Lambert, TN Jarvinen, GD Gopalan, AS AF Lambert, TN Jarvinen, GD Gopalan, AS TI Syntheses of some new polyaminocarboxylate and CMPO calix[4]arene chelators for the selective extraction of actinide ions SO TETRAHEDRON LETTERS LA English DT Article DE supramolecular chemistry; calixarenes; chelation; actinides; extraction ID SEQUESTERING AGENTS; PLUTONIUM; AMERICIUM; THORIUM; DESIGN AB The syntheses of two new calix[4]arene derivatives designed for the selective liquid-liquid extraction of actinide ions have been achieved. The first, is a novel organic soluble calix[4]arene chelator 2 having four iminocarboxylate ligand moieties anchored to the lower rim. The second calix[4]arene derivative 3 that has been readily synthesized has four CMPO ligand groups tethered to the lower rim. Preliminary studies show that both 2 and 3 extract thorium(IV) more efficiently than europium(III) under acidic conditions into chloroform. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 New Mexico State Univ, Dept Chem & Biochem, Las Cruces, NM 88003 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Gopalan, AS (reprint author), New Mexico State Univ, Dept Chem & Biochem, Las Cruces, NM 88003 USA. NR 17 TC 20 Z9 21 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0040-4039 J9 TETRAHEDRON LETT JI Tetrahedron Lett. PD FEB 26 PY 1999 VL 40 IS 9 BP 1613 EP 1616 DI 10.1016/S0040-4039(99)00070-2 PG 4 WC Chemistry, Organic SC Chemistry GA 167GQ UT WOS:000078624500001 ER PT J AU Lu, P He, S Li, FX Jia, QX AF Lu, P He, S Li, FX Jia, QX TI Epitaxial growth of RuO2 thin films by metal-organic chemical vapor deposition SO THIN SOLID FILMS LA English DT Article DE metal-organic chemical vapor deposition; ruthenium oxide; epitaxial growth; thin film; deposition process ID SPUTTERED RUTHENIUM DIOXIDE; OXIDE; ELECTRODE; SURFACE; SI AB Conductive RuO2 thin films were epitaxially grown on LaAlO3(100) and MgO(100) substrates by metal-organic chemical vapor deposition (MOCVD). The deposited RuO2 films were crack-free, and well adhered to the substrates. The RuO2 film is (200) oriented on LaAlO3(100) substrates at deposition temperature of 600 degrees C and (110) oriented on MgO(100) substrates at deposition temperature or 350 degrees C and above. The epitaxial growth of RuO2 on MgO and LaAlO3 is demonstrated by strong in-plane orientation of thin films with respect to the major axes of the substrates. The RuO2 films on MgO(100) contain two variants and form an orientation relationship with MgO given by RuO2(110)//McO(100) and RuO2[001]//MgO[011]. The RuO2 films on LaAlO3(100), on the other hand, contain four variants and form an orientation relationship with LaAlO3 given by RuO2(200)//LaAlO3(100) and RuO2[011]//LaAlO3[011]. Electrical measurements on the RuO2 thin films deposited at 600 degrees C show room-temperature resistivities of similar to 40 and similar to 50 mu Ohm cm for the films deposited on the MgO and LaAlO3 substrates, respectively. (C) 1999 Elsevier Science S.A. All rights reserved. C1 New Mexico Inst Min & Technol, Dept Mat Sci & Engn, Socorro, NM 87801 USA. Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Lu, P (reprint author), New Mexico Inst Min & Technol, Dept Mat Sci & Engn, Socorro, NM 87801 USA. RI Jia, Q. X./C-5194-2008 NR 21 TC 18 Z9 18 U1 1 U2 5 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 FEB 26 PY 1999 VL 340 IS 1-2 BP 140 EP 144 DI 10.1016/S0040-6090(98)01396-0 PG 5 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 179WM UT WOS:000079353000024 ER PT J AU Guclu, MC Li, J Umar, AS Ernst, DJ Strayer, MR AF Guclu, MC Li, J Umar, AS Ernst, DJ Strayer, MR TI Electromagnetic lepton-pair production in relativistic heavy-ion collisions SO ANNALS OF PHYSICS LA English DT Article ID ELECTRON-POSITRON PAIRS; IMPACT-PARAMETER DEPENDENCE; PI-P COLLISIONS; PARTICLE-PRODUCTION; 2-PHOTON MECHANISM; COULOMB COLLISIONS; DILEPTON EMISSION; COHERENT HIGGS; FIXED TARGETS; SULFUR IONS AB In relativistic heavy-ion collisions, the strong Lorentz-contracted electromagnetic fields are capable of producing copious numbers of lepton pairs through the two-photon mechanism. We provide a new and more general derivation of the Poisson distribution for multiple-pair production and develop a hybrid Monte Carlo technique for calculating the impact parameter dependence and the related multiple-pair production in the two-photon external-field model. Computations for 200 GeV/nucleon sulfur incident on a gold target are compared with recent data. There is good agreement for all but the most energetic pairs, where the theory underpredicts the data. We investigate the ability of the equivalent-photon approximation to predict the impact-parameter dependence of the process, as well as multipair production. We find that the approximation is limited in its ability to address these phenomena. (C) 1999 Academic Press. C1 Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. Tech Univ Istanbul, Dept Phys, Maslak, Turkey. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. RP Ernst, DJ (reprint author), Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. RI Umar, Ahmet/J-4125-2013 OI Umar, Ahmet/0000-0002-9267-5253 NR 76 TC 13 Z9 13 U1 0 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 FEB 25 PY 1999 VL 272 IS 1 BP 7 EP 48 DI 10.1006/aphy.1998.5876 PG 42 WC Physics, Multidisciplinary SC Physics GA 170AY UT WOS:000078784000002 ER PT J AU Baker, RD Schubert, G Jones, PW AF Baker, RD Schubert, G Jones, PW TI High Rayleigh number compressible convection in Venus' atmosphere: Penetration, entrainment, and turbulence SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID GRAVITY-WAVES; NUMERICAL-SIMULATION; CELLULAR CONVECTION; RADIO OCCULTATION; CLOUD PATTERNS; GENERATION; GALILEO; LAYERS AB Numerical simulations of two-dimensional, nonlinear fully compressible convection at the subsolar point in the clouds of Venus are presented. One moderate Rayleigh number case (Ra-q = 6.8 x 10(6)) and two high Rayleigh number (Ra-q = 1.1 x 10(9)) cases are considered. Cloud-level convection is characterized by cold, narrow downwellings that deeply penetrate the underlying stable layer and that entrain warmer air from the overlying stable layer. The convection layer depth, as determined from the horizontally averaged static stability, spans 9 km (47-56 km altitude) and 14 km (46-60 km altitude) for the moderate Rayleigh number and high Rayleigh number simulations, respectively. In the high Rayleigh number cases, convective penetration extends over a scale height from the bottom of the convection layer down to 38 km altitude. Strong convective entrainment completely erodes the overlying stable layer in the high Ra-q cases and incorporates it into the convection layer. The timescale for entrainment of the overlying stable layer is roughly 1 day and may explain why cellular features are predominantly found near and downwind of the subsolar point. The high Rayleigh number simulations are convectively turbulent and exhibit a spectral energy cascade of k(-3), where k is the horizontal wavenumber. Our results suggest that cellular features in the subsolar region are observed at the cloud tops because convection may extend to much higher altitudes there. Downward penetrative convection may also be responsible for turbulence observed in Venus' atmosphere at 45 km altitude. C1 NASA, Mesoscale Atmospher Proc Branch, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90024 USA. Univ Illinois, Natl Ctr Supercomp Applicat, Urbana, IL 61801 USA. San Diego Supercomp Ctr, San Diego, CA USA. RP Baker, RD (reprint author), NASA, Mesoscale Atmospher Proc Branch, Goddard Space Flight Ctr, Univ Space Res Assoc, Code 912, Greenbelt, MD 20771 USA. EM rbaker@agnes.gsfc.nasa.gov; schubert@ucla.edu; pwjones@lanl.gov NR 69 TC 9 Z9 9 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD FEB 25 PY 1999 VL 104 IS E2 BP 3815 EP 3832 DI 10.1029/1998JE900029 PG 18 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 169QP UT WOS:000078760300003 ER PT J AU Hahn, C Lippert, T Wokaun, A AF Hahn, C Lippert, T Wokaun, A TI Comparison of the ablation behavior of polymer films in the IR and UV with nanosecond and picosecond pulses SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID ULTRAVIOLET-LASER ABLATION; HOT-SPOTS; DOPANT; METHACRYLATE; POLY(TETRAFLUOROETHYLENE); MECHANISM; DYNAMICS AB Experiments are performed to compare the ablation behavior in the IR and UV spectral regions of a doped standard polymer, PMMA, and a specially tailored photopolymer, i.e., a triazene copolyester, to elucidate the underlying mechanisms. The results are discussed in light of current theories about photochemical and photothermal pathways of ablation. Further experiments are performed with nanosecond and picosecond pulses to study the impact of pulse length on the material. From the failure to induce ablation in the IR by doping the specialty polymer with an optical molecular heater we conclude that etching in the UV of this compound is mainly governed by a photochemical process. This result is contrasted by successful ablation of doped PMMA in the IR via a thermal unzipping mechanism. With respect to practical applications, the results show convincingly that the presence of an absorbing chromophore in the polymer is a prerequisite for achieving high-resolution structuring, since molecular absorption is required for an efficient distribution of incorporated photonic energy. C1 Paul Scherrer Inst, CH-5232 Villigen, Switzerland. Swiss Fed Inst Technol, Dept Chem Engn & Ind Chem, CH-8092 Zurich, Switzerland. Univ Calif Los Alamos Natl Lab, Div Chem Sci & Technol, Los Alamos, NM 87545 USA. RP Wokaun, A (reprint author), Paul Scherrer Inst, CH-5232 Villigen, Switzerland. RI Lippert, Thomas/N-2423-2016 NR 23 TC 18 Z9 18 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD FEB 25 PY 1999 VL 103 IS 8 BP 1287 EP 1294 DI 10.1021/jp983609j PG 8 WC Chemistry, Physical SC Chemistry GA 174BT UT WOS:000079014800013 ER PT J AU Kuehner, DE Engmann, J Fergg, F Wernick, M Blanch, HW Prausnitz, JM AF Kuehner, DE Engmann, J Fergg, F Wernick, M Blanch, HW Prausnitz, JM TI Lysozyme net charge and ion binding in concentrated aqueous electrolyte solutions SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID PHENOMENOLOGICAL LINKAGE RELATIONS; CONTINUUM ELECTROSTATIC MODEL; INDUCED PROTEIN PRECIPITATION; DYNAMIC LIGHT-SCATTERING; INTERFACIAL THERMODYNAMICS; GLOBULAR-PROTEINS; TITRATION CURVES; PHASE-EQUILIBRIA; ACIDIC RESIDUES; PK(A) AB Hydrogen-ion titrations were conducted for hen-egg-white lysozyme in solutions of potassium chloride over the range pH 2.5-11.5 and for ionic strengths to 2.0 M. The dependence of lysozyme's net proton charge, z(P), on pH and ionic strength in potassium chloride solution is measured. From the ionic-strength dependence of z(P), interactions of lysozyme with potassium and chloride ions are calculated using the molecular-thermodynamic theory of Fraaije and Lyklema.(1) Lysozyme interacts preferentially with up to 12 chloride ions at pH 2.5. The observed dependence of ion-protein interactions on pH and ionic strength is explained in terms of electric-double-layer theory. New experimental pK(a) data are reported for 11 amino acids in potassium chloride solutions of ionic strength to 3.0 M. C1 Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. 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 26 TC 159 Z9 159 U1 0 U2 24 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 FEB 25 PY 1999 VL 103 IS 8 BP 1368 EP 1374 DI 10.1021/jp983852i PG 7 WC Chemistry, Physical SC Chemistry GA 174BT UT WOS:000079014800024 ER PT J AU Breiland, WG Coltrin, ME Creighton, JR Hou, HQ Moffat, HK Tsao, JY AF Breiland, WG Coltrin, ME Creighton, JR Hou, HQ Moffat, HK Tsao, JY TI Organometallic vapor phase epitaxy (OMVPE) SO MATERIALS SCIENCE & ENGINEERING R-REPORTS LA English DT Review DE organometallic vapor phase epitaxy (OMVPE); rotating disk reactors (RDRs); AlGaAs ID MOLECULAR-BEAM EPITAXY; REFLECTANCE-DIFFERENCE SPECTROSCOPY; 001 GAAS-SURFACES; ROTATING-DISK; CARBON-TETRACHLORIDE; GAAS(100) SURFACES; DEPOSITION REACTOR; TRIMETHYL-GALLIUM; MONOLAYER GROWTH; HEAT-TRANSFER AB Organometallic vapor phase epitaxy (OMVPE) has emerged in this past decade as a flexible and powerful epitaxial materials synthesis technology for a wide range of compound-semiconductor materials and devices. Despite its capabilities and rapidly growing importance, OMVPE is far from being well understood: it is exceedingly complex, involving the chemically reacting flow of mixtures of organometallic, hydride and carrier-gas precursors. Recently, however, OMVPE technologies based on high-speed rotating disk reactors (RDRs) have become increasingly common. As fluid flow in these reactors is typically cylindrically symmetric and laminar, its effect on the overall epitaxial growth process is beginning to be unraveled through quantitative computer models. In addition, over the past several years, a combination of well-controlled surface science and RDR-based growth-rate measurements has led to a richer understanding of some of the critical gas and surface chemistry mechanisms underlying OMVPE. As a consequence, it is becoming increasingly possible to develop a quantitative and physically based understanding of OMVPE in particular chemical systems. In this article, we review this understanding for the important specific case of AlGaAs OMVPE in an RDR under conditions used for growing typical device heterostructures. Our goal is to use typical growth conditions as a starting point for a discussion of fundamental physical and chemical phenomena, beginning with the fluid flow through an RDR and ending with the chemical reactions on the surface. By focusing on one particularly important yet relatively simple specific case, this review differs from more comprehensive previous reviews. Viewed as a case study, though, it complements these previous reviews by illustrating the wide diversity of research that is related to OMVPE. It can also serve as a good starting point for the development and transfer of insights into other more complex cases, such as: OMVPE of materials families containing Sb, P or N species, of other devices types, and in other more complex reactor geometries. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Sandia Natl Labs, Ctr Compound Semicond Sci & Technol, Albuquerque, NM 87185 USA. RP Breiland, WG (reprint author), Sandia Natl Labs, Ctr Compound Semicond Sci & Technol, POB 5800, Albuquerque, NM 87185 USA. NR 75 TC 30 Z9 33 U1 1 U2 18 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0927-796X J9 MAT SCI ENG R JI Mater. Sci. Eng. R-Rep. PD FEB 25 PY 1999 VL 24 IS 6 BP 241 EP 274 DI 10.1016/S0927-796X(98)00018-7 PG 34 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 180LV UT WOS:000079388200001 ER PT J AU Venezuela, P Tersoff, J Floro, JA Chason, E Follstaedt, DM Liu, F Lagally, MG AF Venezuela, P Tersoff, J Floro, JA Chason, E Follstaedt, DM Liu, F Lagally, MG TI Self-organized growth of alloy superlattices SO NATURE LA English DT Article ID QUANTUM-DOT SUPERLATTICES; STEP-FLOW GROWTH; SEMICONDUCTORS; DECOMPOSITION; STRESS AB Patterning in nature typically occurs through self-organization, and interest has developed recently in the use of such spontaneous processes to fabricate periodically structured materials at the nanometre scale. For example, ordered arrays of semiconductor 'quantum dot' particles (superlattices) have been created by deposition from a suspension(1), or by self-organization of diffusing atoms on surfaces(2) or in sequentially grown stacked layers(3). The spontaneous formation of layered structures in epitaxial growth has also been reported, and attributed to the process of spinodal decomposition(4,5). Yet highly ordered layered superlattices, developed for applications in optoelectronics (and in future perhaps for thermoelectrics(6)), are created 'by hand' through the sequential deposition of two different materials. Here we show that superlattices can appear spontaneously during crystal growth of an alloy, as appear spontaneously a consequence of the distribution of strain at surface step sites. When a strained alloy grows by 'step flow', the surface steps form periodic bunches(7). We find that the resulting modulated strain field biases the incorporation of the respective alloy components at different steps in the bunch, leading to segregation and superlattice formation. We also present experimental observations (X-ray diffraction and electron microscopy) of a silicon-germanium alloy grown on silicon, which show clear evidence for the formation of such a self-organized structure. C1 IBM Corp, Div Res, Thomas J Watson Res Ctr, Yorktown Heights, NY 10598 USA. Univ Wisconsin, Dept Mat Sci & Engn, Madison, WI 53706 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Tersoff, J (reprint author), IBM Corp, Div Res, Thomas J Watson Res Ctr, POB 218, Yorktown Heights, NY 10598 USA. NR 13 TC 68 Z9 68 U1 2 U2 44 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD FEB 25 PY 1999 VL 397 IS 6721 BP 678 EP 681 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 171AP UT WOS:000078840100045 ER PT J AU Aitala, EM Amato, S Anjos, JC Appel, JA Ashery, D Banerjee, S Bediaga, I Blaylock, G Bracker, SB Burchat, PR Burnstein, RA Carter, T Carvalho, HS Copty, NK Cremaldi, LM Darling, C Denisenko, K Fernandez, A Fox, GF Gagnon, P Gerzon, S Gobel, C Gounder, K Halling, AM Herrera, G Hurvits, G James, C Kasper, PA Kwan, S Langs, DC Leslie, J Lichtenstadt, J Lundberg, B MayTal-Beck, S Meadows, BT Neto, JRTD Mihalcea, D Milburn, RH de Miranda, JM Napier, A Nguyen, A d'Oliveira, AB O'Shaughnessy, K Peng, KC Perera, LP Purohit, MV Quinn, B Radeztsky, S Rafatian, A Reay, NW Reidy, JJ dos Reis, AC Rubin, HA Sanders, DA Santha, AKS Santoro, AFS Schwartz, AJ Sheaff, M Sidwell, RA Slaughter, AJ Sokoloff, MD Solano, J Stanton, NR Stefanski, RJ Stenson, K Summers, DJ Takach, S Thorne, K Tripathi, AK Watanabe, S Weiss-Babai, R Wiener, J Witchey, N Wolin, E Yang, SM Yi, D Yoshida, S Zaliznyak, R Zhang, C AF Aitala, EM Amato, S Anjos, JC Appel, JA Ashery, D Banerjee, S Bediaga, I Blaylock, G Bracker, SB Burchat, PR Burnstein, RA Carter, T Carvalho, HS Copty, NK Cremaldi, LM Darling, C Denisenko, K Fernandez, A Fox, GF Gagnon, P Gerzon, S Gobel, C Gounder, K Halling, AM Herrera, G Hurvits, G James, C Kasper, PA Kwan, S Langs, DC Leslie, J Lichtenstadt, J Lundberg, B MayTal-Beck, S Meadows, BT Neto, JRTD Mihalcea, D Milburn, RH de Miranda, JM Napier, A Nguyen, A d'Oliveira, AB O'Shaughnessy, K Peng, KC Perera, LP Purohit, MV Quinn, B Radeztsky, S Rafatian, A Reay, NW Reidy, JJ dos Reis, AC Rubin, HA Sanders, DA Santha, AKS Santoro, AFS Schwartz, AJ Sheaff, M Sidwell, RA Slaughter, AJ Sokoloff, MD Solano, J Stanton, NR Stefanski, RJ Stenson, K Summers, DJ Takach, S Thorne, K Tripathi, AK Watanabe, S Weiss-Babai, R Wiener, J Witchey, N Wolin, E Yang, SM Yi, D Yoshida, S Zaliznyak, R Zhang, C CA Fermilab E791 Collaborat TI Search for the pentaquark via the P-(c)over-bars(0)-> K*(0)K(-)p decay SO PHYSICS LETTERS B LA English DT Article ID N-C LIMIT; H-DIBARYON; CHARM; MODEL; BARYONS; PHYSICS AB We have searched for evidence of the production and decay of a neutral bound-state pentaquark, one of a predicted doublet of states: P-(c over bar s)(0) = \(c) over bar suud] and P-(c over bar s)(-) = \(c) over bar sddu]. Specifically, we have searched for the decay P-(c over bar s)(0) --> K *K-0(-) p in data from Fermilab experiment E791, in which a 500 GeV/c pi(-) beam interacted with nuclear targets. We find mass-dependent upper limits at the 90% confidence level for the ratio of cross section times branching fraction of this decay relative to that for the decay D-s(-) --> K *K-0(-). The upper limits vary between 0.016 and 0.036 for M(P-(c over bar s)(0)) between 2.75 and 2.91 GeV/c(2), assuming a pentaquark lifetime of 0.4 ps. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Mississippi, University, MS 38677 USA. Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. Univ Cincinnati, Cincinnati, OH 45221 USA. CINVESTAV, Mexico City 07000, DF, Mexico. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. IIT, Chicago, IL 60616 USA. Kansas State Univ, Manhattan, KS 66506 USA. Univ Massachusetts, Amherst, MA 01003 USA. Princeton Univ, Princeton, NJ 08544 USA. Univ Autonoma Puebla, Puebla 72570, Mexico. Univ S Carolina, Columbia, SC 29208 USA. Stanford Univ, Stanford, CA 94305 USA. Tel Aviv Univ, IL-69978 Tel Aviv, Israel. Tufts Univ, Medford, MA 02155 USA. Univ Wisconsin, Madison, WI 53706 USA. Yale Univ, New Haven, CT 06511 USA. RP Aitala, EM (reprint author), Univ Mississippi, University, MS 38677 USA. RI Anjos, Joao/C-8335-2013; Santoro, Alberto/E-7932-2014; Gobel Burlamaqui de Mello, Carla /H-4721-2016 OI Gobel Burlamaqui de Mello, Carla /0000-0003-0523-495X NR 29 TC 27 Z9 27 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 FEB 25 PY 1999 VL 448 IS 3-4 BP 303 EP 310 DI 10.1016/S0370-2693(99)00058-1 PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 174XF UT WOS:000079061200021 ER PT J AU Chilakapati, A AF Chilakapati, A TI A characteristic-conservative model for Darcian advection SO ADVANCES IN WATER RESOURCES LA English DT Article DE Darcy flow; solute transport; volume balance; modified method of characteristics; ELLAM ID LOCALIZED ADJOINT METHOD; FINITE-ELEMENT; TRANSPORT; EQUATION; FLOW AB A numerical method based on the modified method of characteristics is developed for incompressible Darcy flow. Fluid elements modeled as grid cells are mapped back in time to their twisted forms and a strict equality of volumes is imposed between the two. These relations are then cast in terms of potentials using Darcy's law and a nonlinear algebraic problem is solved for potentials. Though a general technique for obtaining Darcy flow, this method is most useful when the solute advection problem also is solved with the modified method of characteristics. The combined technique (referred to as the characteristic-conservative method) using the same characteristics to obtain both velocities and concentrations is then a direct numerical approximation to the Reynolds transport theorem. The method is implemented in three dimensions and a few sample problems featuring nonuniform flow-fields are solved to demonstrate the exact mass conservation property. Inflow and outflow boundaries do not cause any problems in the implementation, in all cases, the characteristic-conservative method obtains velocities that preserve fluid volume and, concentrations that achieve exact local and global mass balance; a desirable property that usually eludes characteristics based methods for solute advection in multidimensional, nonuniform flowfields. (C) 1999 Elsevier Science Limited. Ail rights reserved. C1 Pacific NW Lab, Richland, WA 99352 USA. RP Chilakapati, A (reprint author), Pacific NW Lab, Mailstop K9-36,POB 999, Richland, WA 99352 USA. NR 17 TC 9 Z9 9 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0309-1708 J9 ADV WATER RESOUR JI Adv. Water Resour. PD FEB 24 PY 1999 VL 22 IS 6 BP 597 EP 609 DI 10.1016/S0309-1708(98)00036-0 PG 13 WC Water Resources SC Water Resources GA 177LL UT WOS:000079211500005 ER PT J AU Karim, A Douglas, JF Satija, SK Han, CC Goyette, RJ AF Karim, A Douglas, JF Satija, SK Han, CC Goyette, RJ TI Frustrated coalescence in a chemically reactive polymer blend film SO MACROMOLECULES LA English DT Article ID PHASE-SEPARATION KINETICS; POLY(METHYL METHACRYLATE); SPINODAL DECOMPOSITION; IMMISCIBILITY LOOP; BINARY-MIXTURES; BLOCK-COPOLYMER; SOAP BUBBLES; POLYCARBONATE; DYNAMICS; SURFACTANTS AB The phase separation of a thin polymer blend layer undergoing a simultaneous transesterification reaction is examined by a variety of experimental techniques [neutron and X-ray reflectivity, optical microscopy, atomic force microscopy (AFM)] to determine morphological features unique to reactive phase separation. Neutron reflectivity measurements suggest; that a copolymer layer reactively forms at the interface between the phase-separating blend components. Evidence for a copolymer layer is also provided by AFM and optical images which indicate a strong inhibition ("frustration") of droplet coalescence and a tendency of the droplets to cluster in late-stage phase separation. The influence of the transesterification reaction on phase separation is found to depend strongly on temperature. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Argonne Natl Lab, Div Sci Mat, Argonne, IL 60439 USA. Argonne Natl Lab, Div Intense Pulsed Neutron Source, Argonne, IL 60439 USA. RP Karim, A (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 69 TC 13 Z9 13 U1 3 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD FEB 23 PY 1999 VL 32 IS 4 BP 1119 EP 1127 DI 10.1021/ma980296h PG 9 WC Polymer Science SC Polymer Science GA 170KK UT WOS:000078804700021 ER PT J AU Salomons, GJ Singh, MA Bardouille, T Foran, WA Capel, MS AF Salomons, GJ Singh, MA Bardouille, T Foran, WA Capel, MS TI Small-angle X-ray scattering study of craze formation and dynamics in thermoplastics SO MACROMOLECULES LA English DT Article ID HIGH-IMPACT POLYSTYRENE; GLASSY-POLYMERS; DEFORMATION MECHANISMS; INDIRECT-TRANSFORM; TENSILE IMPACT; DIFFRACTION; PARTICLES; TOUGHNESS; SYSTEMS AB a detailed investigation of the microscopic mechanisms of tensile stress deformation was performed. The experiments involved two different thermoplastic materials: high impact polystyrene (HIPS! and a novel polystyrene CPS)-polybutadiene (PB) blend, at temperatures ranging from 30 to 70 degrees C, deformed at a constant uniaxial strain rate. Real-time measurements of the applied stress, X-ray absorption by the sample, and small-angle scattering were used to identify the presence of shear and craze deformation stages. Craze fibril surface energies were determined from calculations of the fibril diameter in order to distinguish between craze growth by the competing mechanisms of chain scission and forced reptation. C1 Queens Univ, Dept Phys, Kingston, ON K7L 3N6, Canada. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Singh, MA (reprint author), Queens Univ, Dept Phys, Kingston, ON K7L 3N6, Canada. NR 33 TC 6 Z9 6 U1 6 U2 15 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD FEB 23 PY 1999 VL 32 IS 4 BP 1264 EP 1270 DI 10.1021/ma980709e PG 7 WC Polymer Science SC Polymer Science GA 170KK UT WOS:000078804700042 ER PT J AU Grossman-Clarke, S Kimball, BA Hunsaker, DJ Long, SP Garcia, RL Kartschall, T Wall, GW Printer, PJ Wechsung, F LaMorte, RL AF Grossman-Clarke, S Kimball, BA Hunsaker, DJ Long, SP Garcia, RL Kartschall, T Wall, GW Printer, PJ Wechsung, F LaMorte, RL TI Effects of elevated atmospheric CO2 on canopy transpiration in senescent spring wheat SO AGRICULTURAL AND FOREST METEOROLOGY LA English DT Article DE carbon dioxide; stomatal conductance; transpiration; photosynthesis; leaf nitrogen; spring wheat; senescence ID CARBON-DIOXIDE ENRICHMENT; STOMATAL CONDUCTANCE; AMBIENT ATMOSPHERE; C-3 PLANTS; WATER-USE; PHOTOSYNTHESIS; LEAF; LEAVES; MODEL; NITROGEN AB The seasonal course of canopy transpiration and the diurnal courses of latent heat flux of a spring wheat crop were simulated for atmospheric CO2 concentrations of 370 and 550 mu mol mol(-1). The hourly weather data, soil parameters and the irrigation and fertilizer treatments of the Free-Air Carbon Dioxide Enrichment wheat experiment in Arizona (1992-1993) were used to drive the model. The simulation results were tested against field measurements with special emphasis on the period between anthesis and maturity. A model integrating leaf photosynthesis and stomatal conductance was scaled to canopy level in order to be used in the wheat growth model. The simulated intercellular CO2 concentration, C-i, was determined from the ratio of C-i to the CO2 concentration at the leaf surface, C-s, the leaf-to-air specific humidity deficit and a possibly unfulfilled transpiration demand, After anthesis, the measured assimilation rates of the flag leaves decreased more rapidly than their stomatal conductances, leading to a rise in the C-i/C-s ratio. In order to describe this observation, an empirical model approach was developed which took into account the leaf nitrogen content for the calculation of the C-i/C-s ratio. Simulation results obtained with the new model version were in good agreement with the measurements. If changes in the C-i/C-s ratio in accordance with the decrease in leaf nitrogen content during leaf senescence were not considered in the model, simulations revealed an underestimation of the daily canopy transpiration of up to 20% and a decrease in simulated seasonal canopy transpiration by 10%. The measured reduction in the seasonal sum of canopy transpiration and soil evaporation owing to CO2 enrichment, in comparison, was only about 5%. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Potsdam Inst Climate Impact Res, D-14412 Potsdam, Germany. ARS, USDA, US Water Conservat Lab, Phoenix, AZ 85040 USA. Univ Essex, Dept Biol Sci, John Tabor Labs, Colchester CO4 3SQ, Essex, England. Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. LI COR Inc, Lincoln, NE 68504 USA. RP Grossman-Clarke, S (reprint author), Potsdam Inst Climate Impact Res, POB 601203, D-14412 Potsdam, Germany. EM sgclarke@primenet.com RI Long, Stephen/A-2488-2008 OI Long, Stephen/0000-0002-8501-7164 NR 55 TC 18 Z9 18 U1 0 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-1923 J9 AGR FOREST METEOROL JI Agric. For. Meteorol. PD FEB 22 PY 1999 VL 93 IS 2 BP 95 EP 109 DI 10.1016/S0168-1923(98)00111-7 PG 15 WC Agronomy; Forestry; Meteorology & Atmospheric Sciences SC Agriculture; Forestry; Meteorology & Atmospheric Sciences GA 170CC UT WOS:000078787400002 ER PT J AU Lozykowski, HJ Jadwisienczak, WM Brown, I AF Lozykowski, HJ Jadwisienczak, WM Brown, I TI Visible cathodoluminescence of GaN doped with Dy, Er, and Tm SO APPLIED PHYSICS LETTERS LA English DT Article ID IMPLANTED GAN; LUMINESCENCE; PHOTOLUMINESCENCE; ERBIUM AB We reported the observation of visible cathodoluminescence of rare-earth Dy, Er, and Tm implanted in GaN. The implanted samples were given isochronal thermal annealing treatments at a temperature of 1100 degrees C in N-2 or NH3, at atmospheric pressure to recover implantation damages and activated the rare-earth ions. The sharp characteristic emission lines corresponding to Dy3+, Er3+, and Tm3+ intra-4f(n)-shell transitions are resolved in the spectral range from 380 to 1000 nm, and observed over the temperature range of 8.5-411 K. The cathodoluminescence emission is only weakly temperature dependent. The results indicate that rare-earth- doped GaN epilayers are suitable as a material for visible optoelectronic devices. (C) 1999 American Institute of Physics. [S0003-6951(99)03808-5]. C1 Ohio Univ, Sch Elect Engn & Comp Sci, Athens, OH 45701 USA. Ohio Univ, Condensed Matter & Surface Sci Program, Athens, OH 45701 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Nicholas Copernicus Univ, Lab Solid State Optoelect, Inst Phys, PL-87400 Torun, Poland. RP Lozykowski, HJ (reprint author), Ohio Univ, Sch Elect Engn & Comp Sci, Athens, OH 45701 USA. EM lozykows@bobcat.ent.ohiou.edu NR 9 TC 162 Z9 164 U1 6 U2 33 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 22 PY 1999 VL 74 IS 8 BP 1129 EP 1131 DI 10.1063/1.123465 PG 3 WC Physics, Applied SC Physics GA 168HG UT WOS:000078685700025 ER PT J AU Chen, Y Snyder, JE Schwichtenberg, CR Dennis, KW Falzgraf, DK McCallum, RW Jiles, DC AF Chen, Y Snyder, JE Schwichtenberg, CR Dennis, KW Falzgraf, DK McCallum, RW Jiles, DC TI Effect of the elastic modulus of the matrix on magnetostrictive strain in composites SO APPLIED PHYSICS LETTERS LA English DT Article AB The effect of the matrix material on the magnetostriction of composites containing highly magnetostrictive particles has been studied. Experimental results showed that the elastic modulus of the matrix is an important factor determining the bulk magnetostriction of the composite. For a series of composites with the same volume fraction of magnetostrictive particles but different matrix materials, the bulk magnetostriction was found to increase systematically with decreasing elastic modulus of the matrix. A model theory for the magnetostriction of such composites has been developed, based on two limiting assumptions: uniform strain or uniform stress inside the composite. The theory was then used to predict the magnetostriction of the entire material from the volume fractions of the components, their elastic moduli and magnetostrictions. These predictions were in agreement with the experimental results. It is concluded that to obtain a high magnetostriction and adequate mechanical properties of a composite, the elastic moduli of the magnetostrictive phase and the matrix should be as close as possible in value. (C) 1999 American Institute of Physics. [S0003-6951(99)03106-X]. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Chen, Y (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RI Jiles, David/H-9548-2012 NR 11 TC 60 Z9 64 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 22 PY 1999 VL 74 IS 8 BP 1159 EP 1161 DI 10.1063/1.123473 PG 3 WC Physics, Applied SC Physics GA 168HG UT WOS:000078685700035 ER PT J AU Im, J Auciello, O Krauss, AR Gruen, DM Chang, RPH Kim, SH Kingon, AI AF Im, J Auciello, O Krauss, AR Gruen, DM Chang, RPH Kim, SH Kingon, AI TI Studies of hydrogen-induced degradation processes in SrBi2Ta2O9 ferroelectric film-based capacitors SO APPLIED PHYSICS LETTERS LA English DT Article AB It is known that the forming gas (N-2-H-2 mixture) annealing process required for microcircuit fabrication results in an unacceptable electrical degradation of SrBi2Ta2O9 (SBT) ferroelectric capacitors due mainly to the interaction of H-2 with the ferroelectric layer of the capacitor. We have found a strong relationship between changes in the surface composition of the ferroelectric layer and the electrical properties of SBT capacitors as a result of hydrogen annealing. Mass spectroscopy of recoiled ions (MSRI) analysis revealed a strong reduction in the Bi signal as a function of exposure to hydrogen at high temperatures (similar to 500 degrees C). The Bi signal reduction correlates with Bi depletion in the SBT surface region. Subsequent annealing in oxygen at temperatures in the range of 700-800 degrees C resulted in the recovery of the MSRI Bi signal, corresponding to the replenishment of Bi in the previously Bi-depleted surface region. X-ray diffraction (XRD) analysis (probing the whole SBT film thickness) showed little difference in the XRD spectra of the SBT films before and after hydrogen and oxygen-recovery annealing. The combined results of the MSRI and XRD analyses can be interpreted as an indication that the degradation of the electrical properties of the SBT capacitors, after hydrogen annealing, is mainly due to the degradation of the near surface region of the SBT layer. (C) 1999 American Institute of Physics. [S0003-6951(99)00608-7]. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. N Carolina State Univ, Dept Mat Sci & Engn, Raleigh, NC 27695 USA. RP Im, J (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. EM im@anl.gov RI Chang, R.P.H/B-7505-2009 NR 5 TC 49 Z9 50 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 22 PY 1999 VL 74 IS 8 BP 1162 EP 1164 DI 10.1063/1.123474 PG 3 WC Physics, Applied SC Physics GA 168HG UT WOS:000078685700036 ER PT J AU Chang, H Takeuchi, I Xiang, XD AF Chang, H Takeuchi, I Xiang, XD TI A low-loss composition region identified from a thin-film composition spread of (Ba1-x-ySrxCay) TiO3 SO APPLIED PHYSICS LETTERS LA English DT Article ID NEAR-FIELD MICROSCOPE; MICROWAVE AB We have generated the thin-film ternary composition spread of (Ba1-x-ySrxCay)TiO3 on an equilateral-triangle-shaped LaAlO3 substrate. Compositional variation within the triangle was achieved by a precisely controlled shutter system inside a pulsed laser deposition chamber, which allows the deposition of precursors with gradient thickness over the length of the substrate. Appropriate postannealing afforded high-quality epitaxial thin films over almost the entire composition region. Mapping of the microwave dielectric properties of the composition-spread chip was performed using a scanning evanescent microwave microscope at 1 GHz. Composition region Ba0.12-0.25Sr0.35-0.47Ca0.32-0.53TiO3 was found to have desirable properties for electronic applications. (C) 1999 American Institute of Physics. [S0003-6951(99)03508-1]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Xiang, XD (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Xiang, Xiaodong/A-9445-2012; Xiang, Xiaodong/A-5936-2017 NR 14 TC 91 Z9 97 U1 1 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 22 PY 1999 VL 74 IS 8 BP 1165 EP 1167 DI 10.1063/1.123475 PG 3 WC Physics, Applied SC Physics GA 168HG UT WOS:000078685700037 ER PT J AU Leon-Escamilla, EA Corbett, JD AF Leon-Escamilla, EA Corbett, JD TI Solid state compounds with tin-tin bonding. Yb36Sn23: A novel compound containing oligomeric tin anions SO INORGANIC CHEMISTRY LA English DT Article ID ZINTL PHASES; TRANSITIONS; CLUSTERS; METALS AB Reaction of appropriate amounts of the elements in Ta at 1100 degrees C leads to formation of the title phase in high yield. Hydrogen impurities in small amounts do not obscure its formation. Yb36Sn23 crystallizes in tetragonal space group P4/mbm (No. 127) with a = 12.3869(5) Angstrom, c = 22.935(1) Angstrom, Z = 2. The structure features a linear tin hexamer, five dimers, and seven isolated tin atoms per formula unit. These proportions lead to a closed-shell oxidation state count for simple octet assignments (Yb+2)(36)(Sn-6(-14))(Sn-2(-6))(5)(Sn-4)(7) and a Zintl phase classification. Dimensionally, all cations appear to be Yb-II. The hexamer of tin atoms has as its genesis the close contact of Sn atoms that center confacial square antiprismatic arrangements of Yb atoms (closely related to the parent W5Si3 structure). These interconnect with elongated square prisms in a 6:1 proportion to generate the n = six member of Parthe's homologous series A(5n+6)B(3n+5). Electrical conductivity measurements as a function of temperature show that the compound is a poor metal (rho(298) approximate to 130 mu Omega.cm). The latter property is not uncommon for compounds containing clusters of the early p elements. C1 Iowa State Univ, DOE, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, DOE, Ames Lab, Ames, IA 50011 USA. RP Corbett, JD (reprint author), Iowa State Univ, DOE, Dept Chem, Ames, IA 50011 USA. NR 33 TC 26 Z9 26 U1 2 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD FEB 22 PY 1999 VL 38 IS 4 BP 738 EP 743 DI 10.1021/ic980861x PG 6 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 171GU UT WOS:000078855500020 ER PT J AU Ding, CF Wang, XB Wang, LS AF Ding, CF Wang, XB Wang, LS TI Photodetachment photoelectron spectroscopy of doubly charged anions: S2O82- SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ELECTROSPRAY MASS-SPECTROMETRY; CYANO ADDUCT-ANIONS; GAS-PHASE; FREE-ENERGIES; HYDRATION; CHEMISTRY; IONS; DIANIONS; SO4(2-) AB A photodetachment photoelectron spectroscopy study of a doubly charged anion (S2O82-) in the gas phase is reported at three photon energies: 193, 266, 355 nm. Adiabatic and vertical electron binding energies of S2O82- were measured to be 1.7+/-0.2 and 2.2+/-0.1 eV, respectively. Several excited states were observed for the S2O8- singly charged anion at 193 nm. The repulsive Coulomb barrier that binds multiply charged anions was clearly shown in the detachment spectra of S2O82-. The effects of the Coulomb barrier to the detachment spectra and electron tunneling through the barrier are presented. The barrier height, which is equivalent to the magnitude of the Coulomb repulsion between the two excess charges in S2O82- was estimated to be similar to 3 eV. (C) 1999 American Institute of Physics. [S0021-9606(99)02208-4]. C1 Washington State Univ, Dept Phys, Richland, WA 99352 USA. Pacific NW Lab, WR Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Wang, LS (reprint author), Washington State Univ, Dept Phys, Richland, WA 99352 USA. NR 29 TC 29 Z9 29 U1 1 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 22 PY 1999 VL 110 IS 8 BP 3635 EP 3638 DI 10.1063/1.478251 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 168AX UT WOS:000078668900001 ER PT J AU Batista, VS Zanni, MT Greenblatt, BJ Neumark, DM Miller, WH AF Batista, VS Zanni, MT Greenblatt, BJ Neumark, DM Miller, WH TI Femtosecond photoelectron spectroscopy of the I-2(-) anion: A semiclassical molecular dynamics simulation method SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID INITIAL-VALUE REPRESENTATION; POTENTIAL-ENERGY CURVES; RESOLVED IONIZATION SPECTROSCOPY; HOMONUCLEAR DIATOMIC IONS; RESONANT RAMAN-SPECTRA; PUMP-PROBE EXPERIMENTS; WAVE-PACKET DYNAMICS; KINETIC-ENERGY; REAL-TIME; MULTIPHOTON IONIZATION AB In this paper we describe a new semiclassical method for simulating femtosecond pump-probe photoelectron spectroscopy, and its implementation to study the excited state photodissociation dynamics of the I-2(-) anion. Our algorithm involves a forward-backward (FB) semiclassical (SC) initial value representation (IVR) method for calculating the time dependent photodetachment spectrum P(epsilon, Delta t) as a function of the kinetic energy epsilon of the photodetached electron and the delay time Delta t between the pump and probe pulses. We describe the radiation-chromophore interaction perturbatively to first order in both pulse fields, assuming the Condon approximation for the electronic transition dipole moments. Our computed spectra are in excellent agreement with full quantum mechanical simulations. (C) 1999 American Institute of Physics. [S0021-9606(99)00107-5]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Batista, VS (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Zanni, Martin/K-2707-2013; Neumark, Daniel/B-9551-2009 OI Neumark, Daniel/0000-0002-3762-9473 NR 98 TC 71 Z9 71 U1 1 U2 15 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 22 PY 1999 VL 110 IS 8 BP 3736 EP 3747 DI 10.1063/1.478263 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 168AX UT WOS:000078668900015 ER PT J AU Zanni, MT Batista, VS Greenblatt, BJ Miller, WH Neumark, DM AF Zanni, MT Batista, VS Greenblatt, BJ Miller, WH Neumark, DM TI Femtosecond photoelectron spectroscopy of the I-2(-) anion: Characterization of the (A)over-tilde ' (2)Pi(g,1/2) excited state SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID PICOSECOND TRANSIENT SPECTRA; HOMONUCLEAR DIATOMIC IONS; POTENTIAL-ENERGY CURVES; I2-(CO2)N CLUSTER IONS; AB-INITIO CALCULATIONS; RECOMBINATION DYNAMICS; GEMINATE RECOMBINATION; VIBRATIONAL-RELAXATION; MOLECULAR-DYNAMICS; CHARGE FLOW AB A potential energy curve for the (A) over tilde' (2)Pi(g,1/2) state of I-2(-) is constructed based on femtosecond photoelectron spectroscopy of the I-2(-) (A) over tilde' 2 Pi(g,1/2) <-- (X) over tilde (2)Sigma(u)(+) transition at 780 nm. The experiment is sensitive to the slope of the repulsive potential wall, the well depth, equilibrium bond length, and the long- range attractive portion of the upper state potential. The (A) over tilde' (2)Pi(g,1/2) potential is fit to a piecewise potential which is flexible in each of these regions. Simulations of the spectrum using a previously determined Morse potential for the (X) over tilde (2)Sigma(u)(+) state of I-2(-) [J. Chem. Phys. 107, 7613 (1997)] yields a well depth (D-e) of 0.017 +/- 0.010 eV for the (A) over tilde' (2)Pi(g,1/2) state with an equilibrium bond length (R-e) of 6.2 +/- 0.6 Angstrom. These values differ significantly from previous semiempirical results. (C) 1999 American Institute of Physics. [S0021-9606(99)00207-X]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Zanni, MT (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Zanni, Martin/K-2707-2013; Neumark, Daniel/B-9551-2009 OI Neumark, Daniel/0000-0002-3762-9473 NR 56 TC 57 Z9 58 U1 2 U2 13 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 22 PY 1999 VL 110 IS 8 BP 3748 EP 3755 DI 10.1063/1.478264 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 168AX UT WOS:000078668900016 ER PT J AU Carey, RM Earle, W Efstathiadis, E Hare, MF Hazen, ES Hughes, BJ Krienen, F Miller, JP Monich, V Ouyang, J Rind, O Roberts, BL Sulak, LR Trofimov, A Varner, G Worstell, WA Benedict, E Logashenko, I Benante, J Brown, HN Bunce, G Cullen, J Danby, GT Geller, J Hseuh, H Jackson, JW Jia, L Kochis, S Larsen, R Lee, YY Mapes, M Meng, W Morse, WM Pai, C Pearson, C Polk, I Prigl, R Rankowitz, S Sandberg, J Semertzidis, YK Shutt, R Snydstrup, L Soukas, A Stillman, A Tallerico, T Tanaka, M Toldo, F von Lintig, D Warburton, D Woodle, K Chertovskikh, A Druzhinin, VP Fedotovich, GV Grigorev, DN Golubev, VB Khazin, BI Maksimov, A Merzliakov, Y Ryskulov, N Serednyakov, S Shatunov, YM Solodov, E Orlov, Y Winn, D Grossmann, A Gerhaeuser, J Jungmann, K von Walter, P zu Putlitz, G Bunker, B Deninger, W Debevec, PT Hertzog, DW Jones, TD Polly, C Sedykh, S Urner, D Haeberlen, U Endo, K Hirabayashi, H Kurokawa, S Yamamoto, A Green, MA Cushman, P Kindem, J Duong, L Giron, S McNabb, R Miller, D Timmermans, C Zimmerman, D Mizumachi, Y Iwasaki, M Ahn, HE Deng, H Dhawan, SK Disco, A Farley, FJM Fei, X Grosse-Perdekamp, M Hughes, VW Kawall, D Redin, SI Steinmetz, A AF Carey, RM Earle, W Efstathiadis, E Hare, MF Hazen, ES Hughes, BJ Krienen, F Miller, JP Monich, V Ouyang, J Rind, O Roberts, BL Sulak, LR Trofimov, A Varner, G Worstell, WA Benedict, E Logashenko, I Benante, J Brown, HN Bunce, G Cullen, J Danby, GT Geller, J Hseuh, H Jackson, JW Jia, L Kochis, S Larsen, R Lee, YY Mapes, M Meng, W Morse, WM Pai, C Pearson, C Polk, I Prigl, R Rankowitz, S Sandberg, J Semertzidis, YK Shutt, R Snydstrup, L Soukas, A Stillman, A Tallerico, T Tanaka, M Toldo, F von Lintig, D Warburton, D Woodle, K Chertovskikh, A Druzhinin, VP Fedotovich, GV Grigorev, DN Golubev, VB Khazin, BI Maksimov, A Merzliakov, Y Ryskulov, N Serednyakov, S Shatunov, YM Solodov, E Orlov, Y Winn, D Grossmann, A Gerhaeuser, J Jungmann, K von Walter, P zu Putlitz, G Bunker, B Deninger, W Debevec, PT Hertzog, DW Jones, TD Polly, C Sedykh, S Urner, D Haeberlen, U Endo, K Hirabayashi, H Kurokawa, S Yamamoto, A Green, MA Cushman, P Kindem, J Duong, L Giron, S McNabb, R Miller, D Timmermans, C Zimmerman, D Mizumachi, Y Iwasaki, M Ahn, HE Deng, H Dhawan, SK Disco, A Farley, FJM Fei, X Grosse-Perdekamp, M Hughes, VW Kawall, D Redin, SI Steinmetz, A TI New measurement of the anomalous magnetic moment of the positive muon SO PHYSICAL REVIEW LETTERS LA English DT Article ID G-2; NMR AB The muon anomalous magnetic moment has been measured in a new experiment at Brookhaven. Polarized muons were stored in a superferric ring, and the angular frequency difference, omega(a), between the spin precession and orbital frequencies was determined by measuring the time distribution of high-energy decay positrons. The ratio R of omega(a) to the Larmor precession frequency of free protons, omega(p), in the storage-ring magnetic field was measured. We find R = 3.707 220(48) X 10(-3). With mu(mu)/mu(p) = 3.183 345 47(47) this gives a(mu+) = 1 165 925(15) X 10(-9) (+/-13 ppm), in good agreement with the previous CERN measurements for mu(+) and mu(-) and of approximately the same precision. C1 Boston Univ, Dept Phys, Boston, MA 02215 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Budker Inst Nucl Phys, Novosibirsk 630090, Russia. Cornell Univ, Newman Lab, Ithaca, NY 14853 USA. Fairfield Univ, Fairfield, CT 06430 USA. Univ Heidelberg, Inst Phys, D-69120 Heidelberg, Germany. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Max Planck Inst Med Forsch, D-69120 Heidelberg, Germany. KEK, High Energy Accelerator Res Org, Tsukuba, Ibaraki 3050801, Japan. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Minnesota, Dept Phys, Minneapolis, MN 55455 USA. Sci Univ Tokyo, Tokyo 162, Japan. Tokyo Inst Technol, Tokyo 152, Japan. Yale Univ, Dept Phys, New Haven, CT 06511 USA. RP Carey, RM (reprint author), Boston Univ, Dept Phys, Boston, MA 02215 USA. RI Jungmann, Klaus/A-7142-2010; jungmann, klaus/H-1581-2013; Semertzidis, Yannis K./N-1002-2013; Logashenko, Ivan/A-3872-2014; Iwasaki, Masahiko/M-8433-2014; OI jungmann, klaus/0000-0003-0571-4072; Iwasaki, Masahiko/0000-0002-3460-9469; Kemp-Benedict, Eric/0000-0001-5794-7172 NR 19 TC 105 Z9 105 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 FEB 22 PY 1999 VL 82 IS 8 BP 1632 EP 1635 DI 10.1103/PhysRevLett.82.1632 PG 4 WC Physics, Multidisciplinary SC Physics GA 168WA UT WOS:000078715100006 ER PT J AU Irwin, J Wang, CX Yan, YT Bane, KLF Cai, Y Decker, FJ Minty, MG Stupakov, GV Zimmermann, F AF Irwin, J Wang, CX Yan, YT Bane, KLF Cai, Y Decker, FJ Minty, MG Stupakov, GV Zimmermann, F TI Model-independent beam dynamics analysis SO PHYSICAL REVIEW LETTERS LA English DT Article AB Using a singular value decomposition of a beam line matrix, composed of many beam position measurements for a large number of pulses, together with the measurement of pulse-by-pulse beam properties or machine attributes, the contributions of each variable to the beam centroid motion can be identified with a gnarly improved resolution. The eigenvalues above the noise floor determine the number of significant physical variables. This method is applicable to storage rings, linear accelerators, and any system involving a number of sources and a larger number of sensors with unknown correlations. Applications are presented from the Stanford Linear Collider. C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Irwin, J (reprint author), Stanford Linear Accelerator Ctr, POB 4349, Stanford, CA 94309 USA. NR 3 TC 33 Z9 34 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 FEB 22 PY 1999 VL 82 IS 8 BP 1684 EP 1687 DI 10.1103/PhysRevLett.82.1684 PG 4 WC Physics, Multidisciplinary SC Physics GA 168WA UT WOS:000078715100019 ER PT J AU Staebler, GM Jackson, GL West, WP Allen, SL Groebner, RJ Schaffer, MJ Whyte, DG AF Staebler, GM Jackson, GL West, WP Allen, SL Groebner, RJ Schaffer, MJ Whyte, DG TI Improved high-confinement mode with neon injection in the DIII-D tokamak SO PHYSICAL REVIEW LETTERS LA English DT Article ID ENERGY CONFINEMENT; TRANSPORT AB The first observation of a high-confinement mode with reduced energy transport in both the center and the edge induced by the injection of neon impurities is reported in this paper. This improved high mode develops from an improved low-confinement mode. Linear growth rate calculations indicate that a new theoretical mechanism, the stabilization of high wave number drift waves by impurities, is at work, combined with E x B velocity shear suppression of low wave number instabilities. C1 Gen Atom Co, San Diego, CA 92186 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. RP Staebler, GM (reprint author), Gen Atom Co, POB 85608, San Diego, CA 92186 USA. NR 16 TC 20 Z9 20 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 22 PY 1999 VL 82 IS 8 BP 1692 EP 1695 DI 10.1103/PhysRevLett.82.1692 PG 4 WC Physics, Multidisciplinary SC Physics GA 168WA UT WOS:000078715100021 ER PT J AU Gammel, PL Barber, BP Ramirez, AP Varma, CM Bishop, DJ Canfield, PC Kogan, VG Eskildsen, MR Andersen, NH Mortensen, K Harada, K AF Gammel, PL Barber, BP Ramirez, AP Varma, CM Bishop, DJ Canfield, PC Kogan, VG Eskildsen, MR Andersen, NH Mortensen, K Harada, K TI Effects of magnetic order on the superconducting length scales and critical fields in single crystal ErNi2B2C SO PHYSICAL REVIEW LETTERS LA English DT Article ID FLUX-LINE-LATTICE; UNIAXIAL SUPERCONDUCTORS; NEUTRON-SCATTERING; COEXISTENCE; STATE AB The flux line form factor in small angle neutron scattering and transport data determines the superconducting length scares and critical fields in single crystal ErNi2B2C. For H parallel to c, the coherence length xi increases and the penetration depth lambda decreases when crossing T-N = 6.0 K, the Neel transition. The critical fields show corresponding anomalies near T-N. For H perpendicular to c, the fourfold modulation of the upper critical field H-c2 is strongly temperature dependent, changing sign near T-N, and can be modeled using the anisotropy of the sublattice magnetization. C1 Lucent Technol, Bell Labs, Murray Hill, NJ 07974 USA. Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames, IA 50011 USA. Riso Natl Lab, DK-4000 Roskilde, Denmark. Hitachi Ltd, Adv Res Lab, Hatoyama, Saitama 35003, Japan. RP Gammel, PL (reprint author), Lucent Technol, Bell Labs, 700 Mt Ave, Murray Hill, NJ 07974 USA. RI Mortensen, Kell/A-5066-2009; Eskildsen, Morten/E-7779-2011; Andersen, Niels/A-3872-2012; Canfield, Paul/H-2698-2014 OI Mortensen, Kell/0000-0002-8998-9390; NR 19 TC 23 Z9 23 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 FEB 22 PY 1999 VL 82 IS 8 BP 1756 EP 1759 DI 10.1103/PhysRevLett.82.1756 PG 4 WC Physics, Multidisciplinary SC Physics GA 168WA UT WOS:000078715100037 ER PT J AU Stratopoulos, GN Dialynas, TE Tsironis, GP AF Stratopoulos, GN Dialynas, TE Tsironis, GP TI Directional Newtonian motion and reversals of molecular motors SO PHYSICS LETTERS A LA English DT Article ID SINGLE KINESIN MOLECULES; MICROTUBULE INTERACTION; HYDROLYSIS; KINETICS; MOVEMENT; MODEL; ATP AB Several biological molecular motors, for instance kinesin and non-claret disjunctional (ncd), belonging to the same superfamily of motor proteins move towards opposite ends of microtubules. It is clear that motor protein motion is powered through ATP hydrolysis, but neither the specifics of the chemical to mechanical energy transduction nor the molecular basis for motion directionality are precisely known, While the protein catalytic domain seems to be responsible for the processibility of the motor on the microtubule, the "neck" region adjacent to the motor heads was found recently to control the directionality of movement. We show here that a simple Newtonian model of two motor head particles connected through a neck coiled-coil spring whose rest length changes with each ATP hydrolysis event captures the essential motor dynamics features. In particular, the observed directionality reversal in chimaeras with different coiled-coil regions results in the model from a change in the stiffness of the spring coefficient. We find that motor speed is determined by the average ATP absorption rate while the effect of ambient temperature is relatively small, leading to essentially non-Brownian, deterministic motor motion. (C) 1999 Published by Elsevier Science B.V. C1 Univ Crete, Dept Phys, Heraklion 71003, Crete, Greece. Fdn Res & Technol Hellas, Heraklion 71003, Crete, Greece. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. RP Stratopoulos, GN (reprint author), Univ Crete, Dept Phys, POB 2208, Heraklion 71003, Crete, Greece. RI Tsironis, George/C-2683-2011 NR 23 TC 34 Z9 34 U1 0 U2 2 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 FEB 22 PY 1999 VL 252 IS 3-4 BP 151 EP 156 DI 10.1016/S0375-9601(98)00938-4 PG 6 WC Physics, Multidisciplinary SC Physics GA 170UK UT WOS:000078825100007 ER PT J AU Zapol, P Jaffe, JB Hess, AC AF Zapol, P Jaffe, JB Hess, AC TI Ab initio study of hydrogen adsorption on the ZnO (1010) surface SO SURFACE SCIENCE LA English DT Article DE ab initio quantum chemical methods and calculations; adatoms; chemisorption; hydrogen; physical adsorption; single crystal surfaces; surface relaxation and reconstruction; zinc oxide ID TOTAL-ENERGY; ZINC-OXIDE; RELAXATION; SOLIDS; H-2; CO AB Chemisorption of hydrogen at half and full monolayer coverage on the nonpolar ZnO (10 (1) over bar 0) surface has been studied by means of the ab initio Hartree-Fock method in the two-dimensionally periodic slab model. Both surface and hydrogen geometry were optimized for hydrogen bound at surface zinc and oxygen atoms. We find adsorption energies to be substantial for heterolytic dissociation of hydrogen molecules. ZnO surface derelaxation plays an important role in the chemistry of the adsorption process. A posteriori correlation corrections to the total energies have been calculated, and the dependence of adsorption properties on surface coverage is discussed. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Michigan Technol Univ, Dept Phys, Houghton, MI 49931 USA. Pacific NW Lab, Div Mat & Chem Sci, Richland, WA 99352 USA. RP Zapol, P (reprint author), Argonne Natl Lab, Div Sci Mat, 9700 S Cass Ave, Argonne, IL 60559 USA. EM zapol@anlchm.chm.anl.gov RI Zapol, Peter/G-1810-2012 OI Zapol, Peter/0000-0003-0570-9169 NR 22 TC 31 Z9 31 U1 0 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD FEB 22 PY 1999 VL 422 IS 1-3 BP 1 EP 7 DI 10.1016/S0039-6028(98)00750-X PG 7 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 172QC UT WOS:000078934500006 ER PT J AU Wan, WS Berz, M AF Wan, WS Berz, M TI Design of a fifth-order achromat SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB A repetitive system free of all aberrations up to the fifth order was designed based on a recently developed analytical theory that, in principle, allows the design of such achromats to an arbitrary order (Wan and Berz, Phys. Rev. E 54 (1996) 2870; Wan, Ph.D. Thesis, Michigan State University, 1995). It serves as an example to show that complete correction of aberrations is possible beyond order three, which is the highest order achieved before (Dragt, Nucl. Instr. and Meth. A 258 (1987) 339; F. Neri, in: Berz, McIntyre (Eds.), Proc. Workshop on High Order Effects). Instead of repetition of identical cells, which is widely used in achromat design based on normal form theory, we utilize cells which are obtained from the original ones through mirror imaging about the x-y plane, which corresponds to a reversion. In our design, the second half of the ring is the reversion of the first one, and two turns make a fifth-order achromat. A possible application of repetitive high-order achromats being time-of-flight spectroscopy, the resulting ring was analyzed with respect to dynamic aperture and energy resolution using maps of orders nine and higher. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. Michigan State Univ, Natl Supercond Cyclotron Lab, E Lansing, MI 48824 USA. RP Wan, WS (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 17 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 21 PY 1999 VL 423 IS 1 BP 1 EP 6 DI 10.1016/S0168-9002(98)01211-X PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 172BH UT WOS:000078901300001 ER PT J AU Alburger, DE Wesselborg, C AF Alburger, DE Wesselborg, C TI Precision energy measurement of the 166 keV gamma ray in Ce-139 decay SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB An intrinsic Ge (LEPS-type) detector was used to measure the energy of the 166 keV gamma ray in Ce-139 decay against the gamma rays of Ta-182. Reference values for Ta-182 were taken from the recent list of gamma ray energy standards as updated by Helmer and van der Leun. Based on 18 runs taken under a variety of conditions, the average value for this La-139 gamma ray is 165.8575(11) keV. This is mid-way between two earlier results, but about six times as accurate. Some advantages of 139Ce as both a gamma ray and internal-conversion electron calibration source are pointed out. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Giessen, Inst Kernphys, D-35392 Giessen, Germany. RP Alburger, DE (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. NR 9 TC 4 Z9 4 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 FEB 21 PY 1999 VL 423 IS 1 BP 49 EP 51 DI 10.1016/S0168-9002(98)01177-2 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 172BH UT WOS:000078901300006 ER PT J AU Cederstrom, B Danielsson, M Lundqvist, M Nygren, D AF Cederstrom, B Danielsson, M Lundqvist, M Nygren, D TI High-resolution X-ray imaging using the signal time dependence on a double-sided silicon detector SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE X-ray imaging; scanned-slit; silicon strip detector; double-sided detector AB The possibility of using drift times for electrons and holes in an edge-on double-sided silicon strip detector to achieve a high resolution X-ray image has been investigated with help of computer simulations. The detector is in a scanned slit X-ray imaging geometry and collects electrons and holes on opposite sides of the silicon wafer. The time displacement between collection of electrons and holes is related to the position across the detector where the X-ray photon converted and the results of the investigation indicate this can be translated into a spatial resolution better than 20 mu m. The advantage of this method is that the resolution is not limited by the slit size allowing several times as many photons contribute to the image and thus reduce the scan-time. The study assumed a 300 mu m thick detector which for a slit-width with the same size results in a 10 times more efficient use of the X-ray source compared to a 30 mu m slit. A thicker detector increases this number, but leads to a higher rate of coincidences that would interfere with the time measurements. It was calculated that an average of 2 MHz incoming photons per strip would give less than 5% coincidences. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Royal Inst Technol, Dept Phys, S-10405 Stockholm, Sweden. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Lundqvist, M (reprint author), Royal Inst Technol, Dept Phys, Frescativagen 24, S-10405 Stockholm, Sweden. NR 16 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 21 PY 1999 VL 423 IS 1 BP 135 EP 145 DI 10.1016/S0168-9002(98)01206-6 PG 11 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 172BH UT WOS:000078901300015 ER PT J AU Fenimore, EE Cooper, C Ramirez-Ruiz, E Sumner, MC Yoshida, A Namiki, M AF Fenimore, EE Cooper, C Ramirez-Ruiz, E Sumner, MC Yoshida, A Namiki, M TI Gamma-ray bursts and relativistic shells: The surface filling factor SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays, bursts; relativity ID AFTERGLOW; MODELS; VARIABILITY; SHOCKS AB The variability observed in many complex gamma-ray bursts (GRBs) is inconsistent with causally connected variations in a single, symmetric, relativistic shell interacting with the ambient material ("external shocks"). Rather, either the central site must produce similar to 10(50) ergs s(-1) for hundreds of seconds ("internal shocks"), or the local spherical symmetry of the shell must be broken on an angular scale much smaller than Gamma(-1), where Gamma is the bulk Lorentz factor for the shell. The observed variability in the external shock models arises from the number of causally connected regions that (randomly) become active. We define the surface filling factor to be the ratio of the area of causally connected regions that become active to the observable area of the shell. From the observed variability in 52 BATSE bursts, we estimate the surface filling factor to be typically similar to 5 x 10(-3), although some values are near unity. We find that the surface filling factor, f, is similar to 0.1 Delta T/T in both the constant Gamma phase (which probably produces the GRB) and the decelerating phase (which probably produces the X-ray afterglows). Here, AT is a typical timescale of variability, and T is the time since the initial signal. We analyze the 2 hr flare seen by ASCA 36 hr after the GRB and conclude that the surface filling factor must be small(10(-3)) in the X-ray afterglow phase as well. Compared with the energy required for an isotropic shell, E-iso, explanations for a low surface filling factor can either require more energy (f(-1) E-iso similar to 10(56) ergs) or less energy [(Delta T/4T)E-2(iso) similar to 10(49) ergs]. Thus, the low filling factor cannot be used as a strong argument that GRBs must be internal shocks. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RIKEN, Inst Phys & Chem Res, Wako, Saitama 3510198, Japan. RP Fenimore, EE (reprint author), Univ Calif Los Alamos Natl Lab, MS D436, Los Alamos, NM 87545 USA. NR 27 TC 37 Z9 37 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 FEB 20 PY 1999 VL 512 IS 2 BP 683 EP 692 DI 10.1086/306786 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 187VP UT WOS:000079809000015 ER PT J AU Griffiths, NW Fisher, GH Woods, DT Siegmund, OHW AF Griffiths, NW Fisher, GH Woods, DT Siegmund, OHW TI SUMER observations of the quiet-Sun transition region SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : transition region; Sun : UV radiation ID UNRESOLVED FINE-STRUCTURES; HIGH-RESOLUTION TELESCOPE; EXTREME-ULTRAVIOLET; SOLAR CHROMOSPHERE; TEMPERATURE REGION; O-IV; S-IV; SPECTRA; CORONA; ZONE AB We present new results from observations of the quiet Sun taken with the SUMER spectrograph on the SOHO spacecraft. This study includes line and continuum emission covering a wide range of temperatures, and the data have been used to create a number of intensity maps with a field of view of similar to 60 " x 300 " and a spatial resolution of similar to 1 ". These maps reveal bright features that extend from similar to 6000 K to similar to 2 MK, indicating that much of the observed transition region emission arises in an atmospheric interface between the chromosphere and corona. The emission-line intensities over our field of view vary by up to 2 orders of magnitude and have lognormal distributions suggestive of small-scale magnetic fragmentation. We find empirical evidence for a power-law relationship between line emission and electron density, with an exponent in the range similar to 0.3-1.0. Possible temperature dependence of the exponent is reflected in the slope of the emission measure curve, which appears to change slightly with varying electron density. However, there is no major variation in the shape of the lower transition region emission measure distribution with either the intensity or the size of the area studied. This indicates that ensembles of "cool loops" (loops physically distinct from those structures which reach coronal temperatures) are unlikely to be the source of this emission unless the size of the structures is considerably less than 1 " We also find that the Li-sequence N v lambda 1240 emission is higher than expected, in agreement with several previous studies. It seems that this effect diminishes with intensity, suggesting that it is unlikely to be due to the omission of density dependence in dielectronic recombination calculations. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. RI Fisher, George/G-1380-2015 OI Fisher, George/0000-0002-6912-5704 NR 46 TC 37 Z9 37 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 FEB 20 PY 1999 VL 512 IS 2 BP 992 EP 1005 DI 10.1086/306794 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 187VP UT WOS:000079809000041 ER PT J AU Rege, MA Yonge, DR Mendoza, DP Petersen, JN Bereded-Samuel, Y Johnstone, DL Apel, WA Barnes, JM AF Rege, MA Yonge, DR Mendoza, DP Petersen, JN Bereded-Samuel, Y Johnstone, DL Apel, WA Barnes, JM TI Selenium reduction by a denitrifying consortium SO BIOTECHNOLOGY AND BIOENGINEERING LA English DT Article DE selenium; denitrify; bioremediation ID THAUERA-SELENATIS; WATER; GROWTH; BIOREMEDIATION; RESERVOIR; OXYANIONS; BACTERIUM; REACTOR AB A denitrifying bacterial consortium obtained from the Pullman, Washington wastewater treatment facility was enriched under denitrifying conditions and its ability to reduce selenite and selenate was studied. Replicate experiments at two different experimental conditions were performed. All experiments were performed under electron-acceptor limiting conditions, with acetate as the carbon source and nitrate the electron acceptor. In the first set of experiments, selenite was present, whereas, in the second set, selenate was added. A significant lag period of approximately 150 h was necessary before selenite or selenate reduction was observed. During this lag period, nitrate and nitrite use was observed. Once selenite or selenate reduction had started, nitrate and nitrite reduction was concomitant with selenium species reduction. Trace amounts of selenite were detected during the selenate reduction study. Analysis of the data indicates that, once selenium species reduction was induced, the rate of reduction was proportional to the selenium species concentration and to the biomass concentration. Furthermore, at similar biomass and contaminant concentrations, selenite reduction is approximately four times faster than selenate reduction. (C) 1999 John Wiley & Sons, Inc. C1 Washington State Univ, Ctr Multiphase Environm Res, Pullman, WA 99164 USA. Idaho Natl Engn & Environm Lab, Dept Biotechnol, Idaho Falls, ID USA. RP Petersen, JN (reprint author), Washington State Univ, Ctr Multiphase Environm Res, Pullman, WA 99164 USA. RI Petersen, James/B-8924-2008 NR 25 TC 22 Z9 22 U1 1 U2 8 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0006-3592 J9 BIOTECHNOL BIOENG JI Biotechnol. Bioeng. PD FEB 20 PY 1999 VL 62 IS 4 BP 479 EP 484 DI 10.1002/(SICI)1097-0290(19990220)62:4<479::AID-BIT11>3.0.CO;2-G PG 6 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA 158KB UT WOS:000078113700011 ER PT J AU Van Mourik, T Wilson, AK Dunning, TH AF Van Mourik, T Wilson, AK Dunning, TH TI Benchmark calculations with correlated molecular wavefunctions. XIII. Potential energy curves for He-2, Ne-2 and Ar-2 using correlation consistent basis sets through augmented sextuple zeta SO MOLECULAR PHYSICS LA English DT Article ID GAUSSIAN-BASIS SETS; CONFIGURATION-INTERACTION CALCULATIONS; PERTURBATIVE ABINITIO CALCULATIONS; AB-INITIO CALCULATIONS; WAVE-FUNCTIONS; MOLLER-PLESSET; HELIUM DIMER; VARIATIONAL CALCULATIONS; SUPERPOSITION ERROR; ELECTRON-AFFINITIES AB The potential energy curves of the rare gas dimers He-2, Ne-2, and Ar-2 have been computed using correlation consistent basis sets ranging from singly augmented aug-cc-pVDZ sets through triply augmented t-aug-cc-pV6Z sets, with the augmented sextuple basis sets being reported herein. Several methods for including electron correlation were investigated, namely Moller-Plesset perturbation theory (MP2, MP3 and MP4) and coupled cluster theory [CCSD and CCSD(T)]. For He-2 CCSD(T)/d-aug-cc-pV6Z calculations yield a well depth of 7.35 cm(-1) (10.58 K), with an estimated complete basis set (CBS) limit of 7.40 cm(-1) (10.65 K). The latter is smaller than the 'exact' well depth (Aziz, R. A., Janzen, A. R., and Moldover, M. R., 1995, Phys. Rev. Lett., 74, 1586) by about 0.2 cm(-1) (0.35 K). The Net well depth, computed with the CCSD(T)/d-aug-cc-pV6Z method, is 28.31 cm(-1) and the estimated CBS limit is 28.4 cm(-1) approximately 1 cm(-1) smaller than the empirical potential of Aziz, R. A., and Slaman, M., J., 1989, Chem. Phys., 130, 187. Inclusion of core and core-valence correlation effects has a negligible effect on the Nea well depth, decreasing it by only 0.04 cm(-1). For Ar-2, CCSD(T)/ d-aug-cc-pV6Z calculations yield a well depth of 96.2 cm(-1). The corresponding HFDID potential of Aziz, R. A., 1993, J. chem. Phys., 99, 4518 predicts of D-e of 99.7 cm(-1). Inclusion of core and core-valence effects in Ar-2 increases the well depth and decreases the discrepancy by approximately 1 cm(-1). C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Van Mourik, T (reprint author), Univ London Univ Coll, Christopher Ingold Labs, 20 Gordon St, London WC1H 0AJ, England. RI van Mourik, Tanja/A-4007-2008 NR 76 TC 174 Z9 174 U1 3 U2 26 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0026-8976 J9 MOL PHYS JI Mol. Phys. PD FEB 20 PY 1999 VL 96 IS 4 BP 529 EP 547 DI 10.1080/00268979909482990 PG 19 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 170TC UT WOS:000078821300009 ER PT J AU Dupuis, M Nicholas, JB AF Dupuis, M Nicholas, JB TI On the electronic structure of Si3O2 and its anion SO MOLECULAR PHYSICS LA English DT Article ID 2ND-ORDER PERTURBATION-THEORY; SILICON-DIOXIDE; BASIS SETS; INTERFACE; CLUSTERS; OXYGEN; DEFECT; GLASS; SIO2; PHOTOLUMINESCENCE AB In a previous study (Wang, L. S., Nicholas, J. B., Dupuis, M., Wu, H., and Colson, S. D., 1997, Phys. Rev. Lett., 78, 4450) of small silicon oxide clusters with stochiometry Si3Oy (y = 1-6), it was found that the molecule Si3O2 and its anion required special theoretical attention. This is due to a particular electronic structure feature of the neutral cluster: the s,p hybrid atomic orbitals of the two bonded silicon atoms give rise to a low lying empty pi molecular orbital. As a result the ground state of Si3O2 has a triplet spin, and a state of singlet spin is a low lying excited electronic state at about 0.5 eV above the triplet state. Ab initio molecular orbital calculations show that photoelectron detachment proceeds from the B-2(1) state of the anion to the B-3(1) ground state of the neutral cluster. Detachment via the (1)A(1) state of the neutral cluster lies in the shoulder of the detachment via the triplet state. C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Dupuis, M (reprint author), Pacific NW Lab, Environm Mol Sci Lab, K1-83,POB 999,906 Battelle Blvd, Richland, WA 99352 USA. NR 24 TC 5 Z9 5 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0026-8976 J9 MOL PHYS JI Mol. Phys. PD FEB 20 PY 1999 VL 96 IS 4 BP 549 EP 553 DI 10.1080/00268979909482991 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 170TC UT WOS:000078821300010 ER PT J AU Head-Gordon, M Oumi, M Maurice, D AF Head-Gordon, M Oumi, M Maurice, D TI Quasidegenerate second-order perturbation corrections to single-excitation configuration interaction SO MOLECULAR PHYSICS LA English DT Article ID MOTION COUPLED-CLUSTER; EXCITED-STATES; ELECTRONIC-TRANSITIONS; RESPONSE FUNCTIONS; EQUATION; ENERGIES; SUBSTITUTIONS; CC2; RADICALS; MODEL AB A family of quasidegenerate second-order perturbation theories that correct excitation energies from single-excitation configuration interaction (CIS) are introduced which generalize the earlier non-degenerate second-order method, CIS(D). The new methods are termed CIS(D-n), where n ranges from 0 to infinity, according to the number of terms retained in a doubles denominator expansion. Truncation at either n = 0 or n = 1 yields methods which involve the diagonalization of a dressed singles-only response matrix, where the dressing is state-independent. Hence CIS(D-0) and CIS(D-1) can be implemented efficiently using semidirect methods, which are discussed. Test calculations on formaldehyde, ethylene, chlorine nitrate, styrene, benzaldehyde, and chalcone are presented to assess the performance of these methods. CIS(D-0) and CIS(D-1) both show significant improvements relative to CIS(D) in cases of near-degeneracy. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Head-Gordon, M (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 33 TC 59 Z9 59 U1 0 U2 8 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0026-8976 J9 MOL PHYS JI Mol. Phys. PD FEB 20 PY 1999 VL 96 IS 4 BP 593 EP 602 DI 10.1080/002689799165459 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 170TC UT WOS:000078821300015 ER PT J AU Grossman, JC Lester, WA Louie, SG AF Grossman, JC Lester, WA Louie, SG TI Cyclopentadiene stability: quantum Monte Carlo, coupled cluster, and density functional theory determinations SO MOLECULAR PHYSICS LA English DT Article ID STRUCTURAL-PROPERTIES; ELECTRON CORRELATION; WAVE-FUNCTIONS; BASIS-SETS; MOLECULES; ATOMS; EXCHANGE; ENERGIES AB The stability of cyclopentadiene is determined using quantum Monte Carlo in both the VMC and DMC variants, HF, CCSD(T), LDA, and the BPW91, B3PW91, BLYP, B3LYP generalized gradient approximation (GGA) density functional theory methods. A comparison with available experimental data shows that the GGAs perform significantly better than LDA and HF for structure optimization. The cyclopentadiene atomization energy calculations reveal that the GGA methods are in fairly good agreement with the DMC result, although a range of similar to 20 kcal mol(-1) is observed among different functionals. Less satisfactory agreement is obtained with the other methods. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Mat Sci Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Grossman, JC (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NR 31 TC 6 Z9 6 U1 1 U2 1 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0026-8976 EI 1362-3028 J9 MOL PHYS JI Mol. Phys. PD FEB 20 PY 1999 VL 96 IS 4 BP 629 EP 632 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 170TC UT WOS:000078821300018 ER PT J AU Maroni, VA Teplitsky, M Rupich, MW AF Maroni, VA Teplitsky, M Rupich, MW TI An environmental scanning electron microscope study of the Ag/Bi-2223 composite conductor from 25 to 840 degrees C SO PHYSICA C LA English DT Article DE environmental scanning electron microscope; Bi-2223; superconductor; phase transformation; microstructure; heat treatment ID LEAD-DOPED BI-2223; THERMODYNAMIC BEHAVIOR; OXYGEN STOICHIOMETRY; PHASE-STABILITY; SUPERCONDUCTOR; TAPES; MECHANISM; PLATELETS; SYSTEMS AB An environmental scanning electron microscope (ESEM) equipped with a hot stage was used to examine phase evolution and microstructural transformations in a partially de-sheathed Ag/Bi-2223 composite conductor as it was heated from ambient temperature to well above 800 degrees C in an oxygen-containing environment. Coarsening of the powder, the opening and eventual filling in of gaps in the powder, recrystallization of the silver sheath, a granular-to-platy transition, platelet-like growth of the layered bismuthates, the formation and spreading of a transient liquid phase, and (at the highest temperatures) partial melting, accompanied by shifting of grain colonies, were all observed in the electron microscope images during various stages of the heating process. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Amer Superconductor, Westborough, MA 01581 USA. RP Maroni, VA (reprint author), Argonne Natl Lab, Bldg 205,9700 S Cass Ave, Argonne, IL 60439 USA. NR 17 TC 19 Z9 22 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD FEB 20 PY 1999 VL 313 IS 3-4 BP 169 EP 174 DI 10.1016/S0921-4534(99)00022-2 PG 6 WC Physics, Applied SC Physics GA 175QR UT WOS:000079106700001 ER PT J AU Ashworth, SP Suenaga, M AF Ashworth, SP Suenaga, M TI Measurement of ac losses in superconductors due to ac transport currents in applied ac magnetic fields SO PHYSICA C LA English DT Article DE superconductors; transport currents; magnetic fields ID BI-2223; TAPES AB A new technique for the measurement of ac losses in superconductors due to applied magnetic fields and transport currents is reported. This technique is derived from consideration of the source of the energy losses, rather than by the imposition of any model for magnetic field distribution within the superconductor and allows us to present new data on the losses in BSCCO-2223 multi-filamentary conductor due to ac fields and de currents, or due to ac fields and ac currents. Based on these measurements we provide guidelines for estimating the losses in BSCCO-2223 conductors. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Div Mat Sci, Upton, NY 11973 USA. RP Ashworth, SP (reprint author), Brookhaven Natl Lab, Div Mat Sci, Bldg 480,POB 5000, Upton, NY 11973 USA. NR 13 TC 42 Z9 42 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD FEB 20 PY 1999 VL 313 IS 3-4 BP 175 EP 187 DI 10.1016/S0921-4534(98)00634-0 PG 13 WC Physics, Applied SC Physics GA 175QR UT WOS:000079106700002 ER PT J AU Ren, ZF Li, W Wang, DZ Lao, JY Wang, JH Paranthaman, M Verebelyi, DT Christen, DK Lee, DF Goyal, A Kroeger, DM AF Ren, ZF Li, W Wang, DZ Lao, JY Wang, JH Paranthaman, M Verebelyi, DT Christen, DK Lee, DF Goyal, A Kroeger, DM TI In-plane aligned superconducting Tl0.78Bi0.22Sr1.6Ba0.4Ca2Cu3O9 films on rolling assisted biaxially textured substrates SO PHYSICA C LA English DT Article DE laser ablation; RABiTS; epitaxy; thallium; superconductor; cerium dioxide ID CRITICAL-CURRENT DENSITY; THIN-FILMS; LASER DEPOSITION; BUFFER LAYERS; TAPES AB In-plane aligned superconducting Tl0.78Bi0.22Sr1.6Ba0.4Ca2Cu3O9 ((Tl,Bi)-1223) films on Rolling Assisted Biaxially Textured Substrates (RABiTS) with J(c) of 4.25 x 10(5) A/cm(2) at 77 K and zero-field have been synthesized by laser ablation and post-ablation annealing. The as-ablated films were amorphous due to the low substrate temperature during ablation. The amorphous films were then wrapped together with an unfired Tl0.95Bi0.22Sr1.6Ba0.4Ca2Cu3O9 pellet in silver foil. The whole package was finally annealed in a tube furnace at 780-810 degrees C for 40-60 min in flowing argon to crystallize the films. X-ray diffraction (XRD) shows that the annealed films consist of mainly c-axis aligned (Tl,Bi)-1223 phase with a small amount of (Tl,Bi)-1212 phase. The full width at half maximum (FWHM) values of XRD peaks show that both phases are epitaxial, with in-plane and out-of-plane alignments comparable to those of the underlying Ni and buffer layers (CeO2 and YSZ). Four-probe transport measurements showed superconducting transition temperatures (T(c)s) of 105-109 K depending on the annealing conditions. With external magnetic field applied parallel to the c-axis, irreversibility magnetic fields reached beyond 3 T at 77 K and beyond 5 T at 64 K. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 SUNY Buffalo, Dept Phys, Ctr Adv Photon & Elect Mat, Buffalo, NY 14260 USA. SUNY Buffalo, Dept Chem, Buffalo, NY 14260 USA. SUNY Buffalo, Dept Phys, Mat Synth Lab, Buffalo, NY 14260 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Ren, ZF (reprint author), SUNY Buffalo, Dept Phys, Ctr Adv Photon & Elect Mat, Buffalo, NY 14260 USA. RI Ren, Zhifeng/B-4275-2014; Paranthaman, Mariappan/N-3866-2015 OI Paranthaman, Mariappan/0000-0003-3009-8531 NR 10 TC 9 Z9 9 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD FEB 20 PY 1999 VL 313 IS 3-4 BP 241 EP 245 DI 10.1016/S0921-4534(99)00018-0 PG 5 WC Physics, Applied SC Physics GA 175QR UT WOS:000079106700010 ER PT J AU Zollino, M Wright, TJ Di Stefano, C Tosolini, A Battaglia, A Altherr, MR Neri, G AF Zollino, M Wright, TJ Di Stefano, C Tosolini, A Battaglia, A Altherr, MR Neri, G TI "Tandem" duplication of 4p16.1p16.3 chromosome region associated with 4p16.3pter molecular deletion resulting in Wolf-Hirschhorn syndrome phenotype SO AMERICAN JOURNAL OF MEDICAL GENETICS LA English DT Article DE chromosome 4p; Wolf-Hirschhorn syndrome; Pitt-Rogers-Danks syndrome; haploinsufficiency; microdeletion ID ROGERS-DANKS-SYNDROME; TRISOMY 4P; TRANSLOCATION; MAP AB Chromosome imbalance affecting the short arm of chromosome 4 results in a variety of distinct clinical conditions. Most of them share a number of manifestations, such as mental retardation, microcephaly, pre- and post-natal growth retardation, anteverted and low-set ears, that can be considered as nonspecific signs, generally attributable to gene dosage impairment. On the other hand, more distinctive phenotypic traits correlate with the segmental aneuploidy, Duplications of the distal half of 4p give rise to the partial trisomy 4 syndrome, characterized by a "boxer" nose configuration and deep-set eyes. These signs are usually observed even in cases of small terminal duplications. Haploinsufficiency of 4p16.3 results in the so-called Wolf-Hirschhorn (WH) syndrome, a contiguous gene syndrome characterized by maxillary hypoplasia, large and protruding eyes, high nasal bridge, skeletal abnormalities, and midline defects. The smallest overlapping deletion described so far as a cause of this condition is only 165 kb long, suggesting that one or a few genes in this region act as "master" regulators of different developmental pathways. A "tandem" duplication of 4p16.1p16.3 was detected in association with a subtle deletion of 4p16.3pter on the same chromosome in a patient with the WH phenotype, The 3.2 Rib deletion, spanning the genomic region from the vicinity of D4S43 to the telomere, encompasses the recently delimited "WHS critical region" [Wright et al., 1997: Hum. Mel. Genet. 6:317-324], This unusual chromosome rearrangement resulted in WH phenotype, clinical manifestations of partial 4p trisomy being mild or absent. This observation led us to speculate that the regulatory gene/genes in the critical WH region affect the expression of other genes in a dose-dependent manner. Haploinsufficiency of this region could be more deleterious than various partial trisomies. (C) 1999 Wiley-Liss, Inc. C1 Univ Cattolica Sacro Cuore, Inst Med Genet, Fac Med A Gemelli, I-00168 Rome, Italy. Univ Calif Los Alamos Natl Lab, Genom Grp, Div Life Sci, Los Alamos, NM USA. Univ Pisa, Ist Sci Stella Maris, Ist Neuropsichiat Infantile, Pisa, Italy. RP Zollino, M (reprint author), Univ Cattolica Sacro Cuore, Inst Med Genet, Fac Med A Gemelli, Largo F Vito 1, I-00168 Rome, Italy. NR 29 TC 17 Z9 17 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 0148-7299 J9 AM J MED GENET JI Am. J. Med. Genet. PD FEB 19 PY 1999 VL 82 IS 5 BP 371 EP 375 PG 5 WC Genetics & Heredity SC Genetics & Heredity GA 169HF UT WOS:000078741100003 PM 10069706 ER PT J AU He, G Macdonald, RG AF He, G Macdonald, RG TI Experimental determination of the nu(1) fundamental vibrational transition moment for HNC SO CHEMICAL PHYSICS LETTERS LA English DT Article ID LINEAR-MOLECULES; DIPOLE-MOMENT; BENDING MODES; INTENSITIES; BANDS; SPECTROSCOPY; FREQUENCIES; PHOTOLYSIS; HCN AB Hydrogen isocyanide, HNC, was generated by the reaction of translationally energetic H atoms with ClCN, and the resulting products, HCl, HCN and HNC, followed by time-resolved infrared absorption spectroscopy. The subsequent reaction of the Cl and CN species with the H atom precursor, CH3SH, resulted in a definite stoichiometric relationship between the stable products and HNC. This stoichiometric relationship was used to relate the HNC absorption to those for HCN and HCl. The v(1) fundamental vibrational transition moment was determined to be 0.141 +/- 0.007 Debye. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Macdonald, RG (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 23 TC 15 Z9 15 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD FEB 19 PY 1999 VL 301 IS 1-2 BP 175 EP 182 DI 10.1016/S0009-2614(98)01445-6 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 167XU UT WOS:000078660800025 ER PT J AU Birnbaum, ER Le Lacheur, RM Horton, AC Tumas, W AF Birnbaum, ER Le Lacheur, RM Horton, AC Tumas, W TI Metalloporphyrin-catalyzed homogeneous oxidation in supercritical carbon dioxide SO JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL LA English DT Article DE oxidation; supercritical carbon dioxide; metalloporphyrins ID HALOGENATED IRON PORPHYRINS; TERT-BUTYL HYDROPEROXIDE; SELECTIVE AIR-OXIDATION; IRON(III) PORPHYRINS; CHEMICAL-REACTIONS; MOLECULAR-OXYGEN; HYDROXYLATION; HYDROGENATION; ALKANES; FLUIDS AB We report results from a study of the reactivity of the halogenated porphyrins tetrakis(pentafluorophenyl)porphyrinato iron(III) chloride [Fe(TFPP)Cl] and beta-octabromo-tetrakis(pentafluorophenyl)porphyrinato iron(III) chloride [Fe(TFPPBr8)Cl] with dioxygen and cyclohexene in supercritical carbon dioxide. A lower limit for the solubility of the iron porphyrins in sc CO2 was determined. Both halogenated metalloporphyrins were active catalysts for oxidation of cyclohexene to epoxide and allylic oxidation products in sc CO2. Ln 12 h at 80 degrees C, up to 350 and 580 turnovers were observed for Fe(TFPP)Cl and Fe(TFPPBr8)Cl, respectively. We have also explored several organic solvent reactions at high temperature and pressure to benchmark relative activity and selectivity. Activity is higher in organic solvent, but accompanied by substantial oxidation of, or reaction with the solvent. Selectivity for epoxidation with Fe(TFPPBr8)Cl is higher in sc CO2 than in organic solvents, with up to 34% cyclohexene oxide produced. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos Initiat, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Tumas, W (reprint author), Univ Calif Los Alamos Natl Lab, Los Alamos Initiat, Chem Sci & Technol Div, MS J514, Los Alamos, NM 87545 USA. NR 50 TC 55 Z9 57 U1 0 U2 14 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1381-1169 J9 J MOL CATAL A-CHEM JI J. Mol. Catal. A-Chem. PD FEB 19 PY 1999 VL 139 IS 1 BP 11 EP 24 DI 10.1016/S1381-1169(98)00172-1 PG 14 WC Chemistry, Physical SC Chemistry GA 157NK UT WOS:000078068400002 ER PT J AU Espenson, JH Zhu, ZL Zauche, TH AF Espenson, JH Zhu, ZL Zauche, TH TI Bromide ions and methyltrioxorhenium as cocatalysts for hydrogen peroxide oxidations and brominations SO JOURNAL OF ORGANIC CHEMISTRY LA English DT Article ID METHYLRHENIUM TRIOXIDE; TETRABUTYLAMMONIUM TRIBROMIDE; MIMICKING; DIOLS AB Oxidation of alcohols by hydrogen peroxide is negligible; even when catalyzed by methyltrioxorhenium (MTO), the process requires a long reaction time. The addition of a catalytic quantity of bromide ions, as HBr or NaBr, greatly enhances the rate. Some of the reactions were carried out on a larger scale in glacial acetic acid, and others at kinetic concentrations. The data establish that Br-2 is the active oxidizing agent in the system, because the catalytic rates under suitable circumstances match those for the independently measured Br-2 reaction with alcohol (benzyl alcohol, in particular). At much lower levels of MTO, however, Br-2 formation plays a role in the kinetics. Certain other reluctant transformations are conveniently carried out with the MTO/H2O/Br- combination: aldehydes to methyl esters; 1,3-dioxolanes to glycol monoesters; and ethers (with cleavage) to ketones (mostly), but in fair yield only. When Br was used in stoichiometric quantity, certain bromination reactions occur. Thus, phenyl acetylenes (PhC2R, R = H, Me, Ph) are converted to dibromoalkenes that are entirely or largely formed as the trans isomer, and phenols are brominated. The latter reaction shows the preference para > ortho > meta. Kinetic studies of benzyl alcohol oxidation with MTO/H2O2/Br- were carried out in aqueous solution. With sufficient (normal) levels of MTO, the rate constant for the formation of benzaldehyde agreed with the independently determined value for Br-2 + PhCH2OH, k = 4.3 x 10(-3) L mol(-1) s(-1) at 25.0 degrees C; for sec-phenethyl alcohol, k = (9.8 +/- 0.4) x 10(-3) L mol(-1) s(-1). Bromine is formed from the known oxidation of Br- with H2O2, catalyzed by MTO. This reaction results in BrO-/HOBr, which is then rapidly converted to Br-2. However, with substantially lower concentrations of MTO, the buildup of benzaldehyde is ca. 4-fold slower, reflecting the diminished rate of Br- oxidation. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP Espenson, JH (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 36 TC 113 Z9 113 U1 2 U2 25 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 FEB 19 PY 1999 VL 64 IS 4 BP 1191 EP 1196 DI 10.1021/jo9817164 PG 6 WC Chemistry, Organic SC Chemistry GA 170UV UT WOS:000078826200021 ER PT J AU Drell, S Jeanloz, R Peurifoy, B AF Drell, S Jeanloz, R Peurifoy, B TI Maintaining a nuclear deterrent under the test ban treaty SO SCIENCE LA English DT Editorial Material C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Univ Calif Berkeley, Dept Geol & Geophys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Sandia Natl Labs, Livermore, CA 94550 USA. RP Drell, S (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 5 TC 10 Z9 10 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 FEB 19 PY 1999 VL 283 IS 5405 BP 1119 EP 1120 DI 10.1126/science.283.5405.1119 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 169GD UT WOS:000078738400029 ER PT J AU Jordan, AD Uwakweh, ONC Maziasz, PJ Porter, WD AF Jordan, AD Uwakweh, ONC Maziasz, PJ Porter, WD TI Unique phase transition in as-cast FeAl-based material SO SCRIPTA MATERIALIA LA English DT Article ID IRON C1 Univ Cincinnati, Dept Mat Sci & Engn, Cincinnati, OH 45221 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Jordan, AD (reprint author), Univ Cincinnati, Dept Mat Sci & Engn, Cincinnati, OH 45221 USA. OI Maziasz, Philip/0000-0001-8207-334X NR 11 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 FEB 19 PY 1999 VL 40 IS 6 BP 711 EP 715 DI 10.1016/S1359-6462(98)00487-4 PG 5 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 179DK UT WOS:000079310200011 ER PT J AU Edelman, A McCorquodale, P Toledo, S AF Edelman, A McCorquodale, P Toledo, S TI The future fast Fourier transform? SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article DE parallel Fourier transforms; fast multipole method ID POWER2; FFTS AB It seems likely that improvements in arithmetic speed will continue to outpace advances in communication bandwidth. Furthermore, as more and more problems are working on huge datasets, it is becoming increasingly likely that data will be distributed across many processors because one processor does not have sufficient storage capacity. For these reasons, we propose that an inexact DFT such as an approximate matrix-vector approach based on singular values or a variation of the Dutt-Rokhlin fast-multipole-based algorithm may outperform any exact parallel FFT. The speedup may be as large as a factor of three in situations where FFT run time is dominated by communication. For the multipole idea we further propose that a method of "virtual charges" may improve accuracy, and we provide an analysis of the singular values that are needed for the approximate matrix-vector approaches. C1 MIT, Dept Math, Cambridge, MA 02139 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Xerox Corp, Palo Alto Res Ctr, Palo Alto, CA 94304 USA. IBM Corp, Thomas J Watson Res Ctr, Yorktown Heights, NY 10598 USA. RP Edelman, A (reprint author), MIT, Dept Math, Cambridge, MA 02139 USA. EM edelman@math.mit.edu; PWMcCorquodale@lbl.gov; toledo@parc.xerox.com NR 23 TC 23 Z9 24 U1 0 U2 1 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 1064-8275 J9 SIAM J SCI COMPUT JI SIAM J. Sci. Comput. PD FEB 19 PY 1999 VL 20 IS 3 BP 1094 EP 1114 PG 21 WC Mathematics, Applied SC Mathematics GA 169UN UT WOS:000078767600007 ER PT J AU Hendrickson, B Jessup, E Smith, C AF Hendrickson, B Jessup, E Smith, C TI Toward an efficient parallel eigensolver for dense symmetric matrices SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article DE eigensolver; Householder tridiagonalization; backtransformation; parallel algorithm; dense matrix; torus wrap mapping ID TRIDIAGONAL EIGENVALUE PROBLEM; LINEAR ALGEBRA SUBPROGRAMS; EXTENDED SET; ALGORITHM; IMPLEMENTATION AB We describe a parallel algorithm for finding the eigenvalues and eigenvectors of a dense symmetric matrix, with an emphasis on the dense linear algebra operations. We follow the traditional three-step process: reduce to tridiagonal form, solve the tridiagonal problem, then backtransform the result. Since the different steps have different algorithmic characteristics, this problem serves as a perfect vehicle for exploring some issues associated with parallel linear algebra calculations. In particular, we examine the effects of matrix distribution and blocking on the computational performance of tridiagonalization and backtransformation. Through experiments on an Intel Paragon, we demonstrate that block storage of the matrix is not necessary for a highly efficient block algorithm. The performance of our approach compares very favorably with that of the corresponding ScaLAPACK routines. C1 Sandia Natl Labs, Appl & Numer Math Dept, Albuquerque, NM 87185 USA. Univ Colorado, Dept Comp Sci, Boulder, CO 80309 USA. Tower Automot, Adv Prod & Proc Technol, Milwaukee, WI 53216 USA. RP Hendrickson, B (reprint author), Sandia Natl Labs, Appl & Numer Math Dept, POB 5800, Albuquerque, NM 87185 USA. EM bah@cs.sandia.gov; jessup@cs.colorado.edu; smith.chris.b@towerautomotive.com NR 43 TC 12 Z9 13 U1 0 U2 2 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 1064-8275 J9 SIAM J SCI COMPUT JI SIAM J. Sci. Comput. PD FEB 19 PY 1999 VL 20 IS 3 BP 1132 EP 1154 PG 23 WC Mathematics, Applied SC Mathematics GA 169UN UT WOS:000078767600009 ER PT J AU Kuhns, PL Brooks, JS Caldwell, T Moulton, WG Reyes, AP Biskup, N Kini, AM Schlueter, JA Wang, HH Geiser, U Williams, JM AF Kuhns, PL Brooks, JS Caldwell, T Moulton, WG Reyes, AP Biskup, N Kini, AM Schlueter, JA Wang, HH Geiser, U Williams, JM TI Microscopic evidence for a partially gapped density wave state in alpha-(BEDT-TTF)(2)KHg(SCN)(4) in high magnetic fields SO SOLID STATE COMMUNICATIONS LA English DT Article DE organic crystals; phase transitions; nuclear resonance ID LOW-TEMPERATURE PHASE; OSCILLATIONS; TRANSITION; CRYSTAL AB We present NMR measurements on alpha-(BEDT-TTF)(2)KHg(SCN)(4), in which the six inner carbon sites of BEDT-TTF are labeled with the C-13 isotope, at low temperatures and in magnetic fields up to 28.8 T. We find, based on microscopic measurements which probe the center of the primary molecular orbital, that the density wave ground state of this system persists up to fields well above the so-called "kink field", a hysteretic transition observed in transport near 23 T below 6 K. The main implication of this result is that in the low temperature limit, the ground state of this material is not fully metallic, but still partially gapped, even to 28.8 T. We obtain a BCS-like relationship between the transition temperature and the energy gap, as derived from the spin relaxation measurements using a simple model. Further, the C-13 NMR spectrum is relatively insensitive to crossing the phase boundary, a result that does not support the notion that the ground state is a conventional spin density wave ground state. (C) 1999 Published by Elsevier Science Ltd. C1 Florida State Univ, Dept Phys, Tallahassee, FL 32310 USA. Florida State Univ, NHMFL, Tallahassee, FL 32310 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Brooks, JS (reprint author), Florida State Univ, Dept Phys, 1800 E Paul Dirac Dr, Tallahassee, FL 32310 USA. RI Kini, Aravinda/F-4467-2012; Biskup, Neven/N-2132-2014 OI Biskup, Neven/0000-0003-0309-0737 NR 23 TC 10 Z9 10 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0038-1098 J9 SOLID STATE COMMUN JI Solid State Commun. PD FEB 19 PY 1999 VL 109 IS 10 BP 637 EP 642 DI 10.1016/S0038-1098(99)00017-4 PG 6 WC Physics, Condensed Matter SC Physics GA 184FZ UT WOS:000079601100005 ER PT J AU Baca, AG Hietala, VM Greenway, D Zolper, JC Dubbert, DF Sloan, LR Shul, RJ AF Baca, AG Hietala, VM Greenway, D Zolper, JC Dubbert, DF Sloan, LR Shul, RJ TI Self-aligned GaAs JFETs for low-power microwave amplifiers and RFICs at 2.4GHz SO ELECTRONICS LETTERS LA English DT Article AB Self-aligned GaAs junction field effect transistor (JFET) narrowband amplifiers operating at 2.4 GHz have been designed and fabricated both with discrete JFETs as a hybrid amplifier and as radiofrequency integrated circuits (RFICs). Enhancement-mode JFETs were used in order to be compatible with complementary digital logic. Hybrid amplifiers achieved 8-10dB of gain at 2.4GHz and 1mW DC bias level. The RFIC achieved 10dB of gain at 2.4 GHz and 2 mW DC bias level. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Off Naval Res, Arlington, VA 22217 USA. RP Baca, AG (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 4 TC 2 Z9 2 U1 0 U2 1 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 0013-5194 J9 ELECTRON LETT JI Electron. Lett. PD FEB 18 PY 1999 VL 35 IS 4 BP 308 EP 309 DI 10.1049/el:19990073 PG 2 WC Engineering, Electrical & Electronic SC Engineering GA 175AK UT WOS:000079068600043 ER PT J AU Thorn, RP Stief, LJ Kuo, SC Klemm, RB AF Thorn, RP Stief, LJ Kuo, SC Klemm, RB TI Photoionization mass spectrometric study of HOCl: Photoionization efficiency spectrum and ionization energy SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID VIBRATION-ROTATION SPECTRA; PHOTOELECTRON-SPECTROSCOPY; ULTRAVIOLET-SPECTRUM; HYPOCHLOROUS ACID; FORCE-FIELD; AB-INITIO; THERMOCHEMISTRY; HALOGENS; CLONO2; CL2O AB The photoionization efficiency (PIE) spectrum of HOCl was measured over the wavelength range lambda = 102-115 nm, using a discharge flow-photoionization mass spectrometer (DF-PIMS) apparatus coupled to a synchrotron radiation source. The PIE spectra displayed steplike behavior near threshold. This study represents the first determination of the HOCl photoionization efficiency spectrum and the photoionization threshold. A value of 11.12(3) +/- 0.01(8) eV was obtained for the adiabatic ionization energy (IE) of HOCl from analysis of photoion thresholds, corresponding to the HOCl+(X(2)A") <-- HOCl(X(1)A") transition. Our PIMS result is identical to the only previous experimental measurement and in good agreement with a recent ab initio calculation. From our result for IE(HOCl), a value of 999.4 +/- 3.6 kJ mol(-1) was calculated for Delta(f)H degrees(0)(HOCl+), and from the latter, the proton affinity of ClO at T = 0 K, PA(o)(ClO), was determined to be 629.6 +/- 3.6 kJ mol(-1). At 298 K, the computed values for Delta(f)H degrees(298)(HOCl+) and PA(298)(ClO) are 996.5 +/- 3.6 and 635.1 +/- 3.6 kJ mol(-1), respectively. C1 NASA, Extraterr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Thorn, RP (reprint author), NASA, Extraterr Phys Lab, Goddard Space Flight Ctr, Code 690, Greenbelt, MD 20771 USA. NR 44 TC 10 Z9 10 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD FEB 18 PY 1999 VL 103 IS 7 BP 812 EP 815 DI 10.1021/jp9834053 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 176KG UT WOS:000079149800006 ER PT J AU Sandrone, G Dixon, DA Hay, BP AF Sandrone, G Dixon, DA Hay, BP TI C(sp(2))-C(sp(3)) rotational barriers in simple amides: H2N-C(=O)-R(R = methyl, ethyl, i-propyl, tert-butyl) SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID CONFIGURATION-INTERACTION CALCULATIONS; MOLECULAR WAVE-FUNCTIONS; NITRIC-ACID SOLUTIONS; GAUSSIAN-BASIS SETS; BENCHMARK CALCULATIONS; SOLVENT-EXTRACTION; DIATOMIC HYDRIDES; FORCE-FIELD; URANIUM(VI); PLUTONIUM(IV) AB Potential energy surfaces for rotation about the C(sp(2))-C(sp(3)) bond are reported for acetamide, propanamide, 2-methylpropanamide, and 2,2-dimethylpropanamide at different levels of ab initio electronic structure theory with correlation effects included. In all cases, fully optimized geometries of rotational minima are consistent with gas phase electron diffraction data and crystal structure data. The experimental barrier height for methyl rotation in acetamide is reproduced to within 0.1 kcal/mol. This study yields a set of improved criteria for the construction of rotational potentials for the C-a-C bond which are used to obtain improved MM3 torsional parameters. In addition, we find that the use of higher levels of theory leads to significantly different results than those obtained in prior Hartree-Fock studies on acetamide and 2-methylpropanamide. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Theory Modeling & Simulat Grp, Richland, WA 99352 USA. RP Pacific NW Natl Lab, Environm Mol Sci Lab, Theory Modeling & Simulat Grp, Richland, WA 99352 USA. NR 73 TC 10 Z9 10 U1 0 U2 5 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 FEB 18 PY 1999 VL 103 IS 7 BP 893 EP 902 DI 10.1021/jp982649k PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 176KG UT WOS:000079149800018 ER PT J AU Rowland, B Winter, PR Ellison, GB Radziszewski, JG Hess, WP AF Rowland, B Winter, PR Ellison, GB Radziszewski, JG Hess, WP TI Photochemistry of matrix-isolated and thin film acid chlorides: Quantum yields and product structures SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID ACETYL-CHLORIDE; PHOTODISSOCIATION; SPECTROSCOPY; COMPLEXES; DYNAMICS; SURFACE; XENON; STATE; CL AB Ultraviolet photoexcitation of matrix-isolated CH3COCl, CH3CH2COCl, and CH3CH2CH2CH2COCl produces HCl . CH2=C=O, HCl . CH3CHC=C=O, and HCl . CH3CH2CH2CHC=C=O complexes. We report precursor and matrix dependent reaction quantum yields. Quantum yield values decrease with increasing alkyl chain length due to a reduced number of alpha H-atoms available for the elimination reaction and steric considerations. We found quantum yields in neat matrixes to be roughly half that in argon or xenon matrixes and assign structures for HCl and ketene complexes in argon and xenon matrixes by comparing IR spectra to ab initio electronic structure calculations. In argon matrixes, the product complex HCl frequency is strongly shifted whereas the ketene remains unshifted with respect to matrix-isolated ketene. In xenon matrixes, HCl . ketene complexes display absorption bands indicative of two distinct structures. Differences between HCl . ketene structures in argon and xenon matrixes are attributed to size differences of the matrix lattice. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Hess, WP (reprint author), Pacific NW Natl Lab, POB 999, Richland, WA 99352 USA. EM wayne.hess@pnl.gov NR 30 TC 4 Z9 4 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD FEB 18 PY 1999 VL 103 IS 7 BP 965 EP 970 DI 10.1021/jp9837481 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 176KG UT WOS:000079149800027 ER PT J AU Bockrath, M Cobden, DH Lu, J Rinzler, AG Smalley, RE Balents, L McEuen, PL AF Bockrath, M Cobden, DH Lu, J Rinzler, AG Smalley, RE Balents, L McEuen, PL TI Luttinger-liquid behaviour in carbon nanotubes SO NATURE LA English DT Article ID QUANTUM WIRES; TEMPERATURES; CONDUCTANCE AB Electron transport in conductors is usually well described by Fermi-liquid theory, which assumes that the energy states of the electrons near the Fermi level E(F) are not qualitatively altered by Coulomb interactions. In one-dimensional systems, however, even weak Coulomb interactions cause strong perturbations, The resulting system, known as a Luttinger liquid, is predicted to be distinctly different from its two- and three-dimensional counterparts(1). For example, tunnelling into a Luttinger liquid at energies near the Fermi level is predicted to be strongly suppressed, unlike in two- and three-dimensional metals. Experiments on one-dimensional semiconductor wires(2,3) have been interpreted by using Luttinger-liquid theory, but an unequivocal verification of the theoretical predictions has not yet been obtained, Similarly, the edge excitations seen in fractional quantum Hall conductors are consistent with Luttinger-liquid behaviour(4,5), but recent experiments failed to confirm the predicted relationship between the electrical properties of the bulk state and those of the edge states(6). Electrically conducting single-walled carbon nanotubes (SWNTs) represent quantum wires(7-10) that may exhibit Luttinger-liquid behaviour(11,12). Here we present measurements of the conductance of bundles ('ropes') of SWNTs as a function of temperature and voltage that agree with predictions for tunnelling into a Luttinger liquid. In particular, we find that the conductance and differential conductance scale as power laws with respect to temperature and bias voltage, respectively, and that the functional forms and the exponents are in good agreement with theoretical predictions. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley 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. Univ Calif Santa Barbara, Inst Theoret Phys, Santa Barbara, CA 93106 USA. RP McEuen, PL (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. EM mceuen@socrates.berkeley.edu RI Lu, Jia Grace/I-7435-2015 OI Lu, Jia Grace/0000-0001-9908-4061 NR 21 TC 1142 Z9 1146 U1 6 U2 111 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD FEB 18 PY 1999 VL 397 IS 6720 BP 598 EP 601 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 169GE UT WOS:000078738500044 ER PT J AU Srivastava, PP AF Srivastava, PP TI Light-front quantized Chiral Schwinger model and its vacuum structure SO PHYSICS LETTERS B LA English DT Article ID QUANTUM ELECTRODYNAMICS; 2 DIMENSIONS; FIELD-THEORY; CONSTRAINTS; VECTOR AB The bosonized Chiral Schwinger model (CSM) is quantized on the Light-front (LF). The physical Hilbert space of CSM is obtained directly once the constraints on the LF phase space are eliminated. The discussion of the degenerate vacua and the absence in the CSM of the theta-vacua, as found in the Schwinger model (SM), becomes straightforward. The differences in the structures of the the mass excitations and the vacua in these gauge theories are displayed transparently. The procedure followed is the one used successfully in the previous works for describing the spontaneous symmetry breaking (SSB) and the SM on the LF. The physical contents following from the LF quantized theory agree with those known in the conventional treatment. The LF hyperplane is argued to be equally appropriate as the conventional equal-time one for the canonical quantization. Some comments on the irrelevance, in quantized field theory, of the fact that the hyperplanes x (+/-)= 0 constitute characteristic surfaces of hyperbolic partial differential equation are also made. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Srivastava, PP (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 33 TC 13 Z9 13 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 FEB 18 PY 1999 VL 448 IS 1-2 BP 68 EP 75 DI 10.1016/S0370-2693(99)00036-2 PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 173NG UT WOS:000078986200011 ER PT J AU Isgur, N AF Isgur, N TI Duality-violating 1/m(Q) effects in heavy quark decay SO PHYSICS LETTERS B LA English DT Article ID OPERATOR PRODUCT EXPANSION; SEMILEPTONIC B-DECAY; EFFECTIVE-FIELD-THEORY; MESON DECAYS; LEPTON SPECTRUM; V-UB; NONPERTURBATIVE CORRECTIONS; VERTICAL-BAR; SUM-RULES; QCD AB I identify a source of Lambda(QCD)/m(Q) corrections to the assumption of quark-hadron duality in the application of heavy quark methods to inclusive heavy quark decays. These corrections could substantially affect the accuracy of such methods in practical applications and in particular compromise their utility for the extraction of the Cabibbo-Kobayashi-Maskawa matrix element V-cb. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Jefferson Lab, Newport News, VA 23606 USA. RP Jefferson Lab, 12000 Jefferson Ave, Newport News, VA 23606 USA. NR 52 TC 28 Z9 28 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 EI 1873-2445 J9 PHYS LETT B JI Phys. Lett. B PD FEB 18 PY 1999 VL 448 IS 1-2 BP 111 EP 118 DI 10.1016/S0370-2693(98)01592-5 PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 173NG UT WOS:000078986200017 ER PT J AU Acciarri, M Achard, P Adriani, O Aguilar-Benitez, M Alcaraz, J Alemanni, G Allaby, J Aloisio, A Alviggi, MG Ambrosi, G Anderhub, H Andreev, VP Angelescu, T Anselmo, F Arefiev, A Azemoon, T Aziz, T Bagnaia, P Baksay, L Balandras, A Ball, RC Banerjee, S Banerjee, S Banicz, K Barczyk, A Barillere, R Barone, L Bartalini, P Basile, M Battiston, R Bay, A Becattini, F Becker, U Behner, F Berdugo, J Berges, P Bertucci, B Betev, BL Bhattacharya, S Biasini, M Biland, A Bilei, GM Blaising, JJ Blyth, SC Bobbink, GJ Bock, R Bohm, A Boldizsar, L Borgia, B Bourilkov, D Bourquin, M Braccini, S Branson, JG Brigljevic, V Brochu, F Brock, IC Buffini, A Buijs, A Burger, JD Burger, WJ Busenitz, J Button, A Cai, XD Campanelli, M Capell, M Romeo, GC Carlino, G Cartacci, AM Casaus, J Castellini, G Cavallari, F Cavallo, N Cecchi, C Cerrada, M Cesaroni, F Chamizo, M Chang, YH Chaturvedi, UK Chemarin, M Chen, A Chen, G Chen, GM Chen, HF Chen, HS Chereau, X Chiefari, G Cifarelli, L Cindolo, F Civinini, C Clare, I Clare, R Coignet, G Colijn, AP Colino, N Costantini, S Cotorobai, F de la Cruz, B Csilling, A Dai, TS van Dalen, JA D'Alessando, R de Asmundis, R Deglon, P Degre, A Deiters, K della Volpe, D Denes, P DeNotaristefani, F De Salvo, A Diemoz, M van Dierendonck, D Di Lodovico, F Dionisi, C Dittmar, M Dominguez, A Doria, A Dova, MT Duchesneau, D Dufournand, D Duinker, P Duran, I Easo, S El Mamouni, H Engler, A Eppling, FJ Erne, FC Extermann, P Fabre, M Faccini, R Falagan, MA Falciano, S Favara, A Fay, J Fedin, O Felcini, M Ferguson, T Ferroni, F Fesefeldt, H Fiandrini, E Field, JH Filthaut, F Fisher, PH Fisk, I Forconi, G Fredj, L Freudenreich, K Furetta, C Galaktionov, Y Ganguli, SN Garcia-Abia, P Gataullin, M Gau, SS Gentile, S Gheordanescu, N Giagu, S Goldfarb, S Gong, ZF Gratta, G Gruenewald, MW van Gulik, R Gupta, VK Gurtu, A Gutay, LJ Haas, D Hartmann, B Hasan, A Hatzifotiadou, D Hebbeker, T Herve, A Hidas, P Hirschfelder, J Hofer, H Holzner, G Hoorani, H Hou, SR Iashvili, I Jin, BN Jones, LW de Jong, P Josa-Mutuberria, I Kasser, A Khan, RA Kamrad, D Kapustinsky, JS Kaur, M Kienzle-Focacci, MN Kim, D Kim, DH Kim, JK Kim, SC Kinnison, WW Kirkby, A Kirkby, D Kirkby, J Kiss, D Kittel, W Klimentov, A Konig, AC Kopp, A Korolko, I Koutsenko, V Kraemer, RW Krenz, W Kunin, A Lacentre, P de Guevara, PL Laktineh, I Landi, G Lapoint, C Lassila-Perini, K Laurikainen, P Lavorato, A Lebeau, M Lebedev, A Lebrun, P Lecomte, P Lecoq, P Le Coultre, P Lee, HJ Le Goff, JM Leiste, R Leonardi, E Levtchenko, P Li, C Lin, CH Lin, WT Linde, FL Lista, L Liu, ZA Lohmann, W Longo, E Lu, W Lu, YS Lubelsmeyer, K Luci, C Luckey, J Luminari, L Lustermann, W Ma, WG Maity, M Majumder, G Malgeri, L Malinin, A Mana, C Mangeol, D Marchesini, P Marian, G Martin, JP Marzano, F Massaro, GGG Mazumdar, K McNeil, RR Mele, S Merola, L Meschini, M Metzger, WJ von der Mey, M Mi, Y Migani, D Mihul, A Milcent, H Miabelli, G Mnich, J Molnar, P Monteleoni, B Moulik, T Mount, R Muanza, GS Muheim, F Muijs, AJM Nahn, S Napolitano, M Nessi-Tedaldi, F Newman, H Niessen, T Nippe, A Nisati, A Nowak, H Oh, YD Organtini, G Ostonen, R Palomares, C Pandoulas, D Paoletti, S Paolucci, P Park, HK Park, IH Pascale, G Passaleva, G Patricelli, S Paul, T Pauluzzi, M Paus, C Pauss, F Peach, D Pedace, M Pei, JJ Pensotti, S Perret-Gallix, D Petersen, B Petrak, S Pevsner, A Piccolo, D Pieri, M Piroue, PA Pistolesi, E Plyaskin, V Pohl, M Pojidaev, V Postema, H Pothier, J Produit, N Prokofiev, D Quartieri, J Rahal-Callot, G Raja, N Rancoita, PG Rattaggi, M Raven, G Razis, P Ren, D Rescigno, M Reucroft, S van Rhee, T Riemann, S Riles, K Robohm, A Rodin, J Roe, BP Romero, L Rosier-Lees, S Rosselet, P Roth, S Rubio, JA Ruschmeier, D Rykaczewski, H Sakar, S Salicio, J Sanchez, E Sanders, MP Sarakinos, ME Schafer, C Schegelsky, V Schmidt-Kaerst, S Schmitz, D Scholz, N Schopper, H Schotanus, DJ Schwenke, J Schwering, G Sciacca, C Sciarrino, D Servoli, L Shevchenko, S Shivarov, N Shoutko, V Shukla, J Shumilov, E Shvorob, A Siedenburg, T Son, D Smith, B Spillantini, P Steuer, M Stickland, DP Stone, A Stone, H Stoyanov, B Straessner, A Sudhakar, K Sultanov, G Sun, LZ Suter, H Swain, JD Szillasi, Z Tang, XW Tauscher, L Taylor, L Timmermans, C Ting, SCC Ting, SM Tonwar, SC Toth, J Tully, C Tung, KL Uchida, Y Ulbricht, J Valente, E Vesztergombi, G Vetlitsky, I Viertel, G Villa, S Vivargent, M Vlachos, S Vogel, H Vogt, H Vorobiev, I Vorobyov, AA Vorvolakos, A Wadhwa, M Wallraff, W Wang, JC Wang, XL Wang, ZM Weber, A Wu, SX Wynhoff, S Xu, ZZ Yang, BZ Yang, CG Yang, HJ Ye, JB Yeh, SC You, JM Zalite, A Zalite, Y Zemp, P Zeng, Y Zhang, ZP Zhu, GY Zhu, RY Zichichi, A Ziegler, F Zilizi, G AF Acciarri, M Achard, P Adriani, O Aguilar-Benitez, M Alcaraz, J Alemanni, G Allaby, J Aloisio, A Alviggi, MG Ambrosi, G Anderhub, H Andreev, VP Angelescu, T Anselmo, F Arefiev, A Azemoon, T Aziz, T Bagnaia, P Baksay, L Balandras, A Ball, RC Banerjee, S Banerjee, S Banicz, K Barczyk, A Barillere, R Barone, L Bartalini, P Basile, M Battiston, R Bay, A Becattini, F Becker, U Behner, F Berdugo, J Berges, P Bertucci, B Betev, BL Bhattacharya, S Biasini, M Biland, A Bilei, GM Blaising, JJ Blyth, SC Bobbink, GJ Bock, R Bohm, A Boldizsar, L Borgia, B Bourilkov, D Bourquin, M Braccini, S Branson, JG Brigljevic, V Brochu, F Brock, IC Buffini, A Buijs, A Burger, JD Burger, WJ Busenitz, J Button, A Cai, XD Campanelli, M Capell, M Romeo, GC Carlino, G Cartacci, AM Casaus, J Castellini, G Cavallari, F Cavallo, N Cecchi, C Cerrada, M Cesaroni, F Chamizo, M Chang, YH Chaturvedi, UK Chemarin, M Chen, A Chen, G Chen, GM Chen, HF Chen, HS Chereau, X Chiefari, G Cifarelli, L Cindolo, F Civinini, C Clare, I Clare, R Coignet, G Colijn, AP Colino, N Costantini, S Cotorobai, F de la Cruz, B Csilling, A Dai, TS van Dalen, JA D'Alessando, R de Asmundis, R Deglon, P Degre, A Deiters, K della Volpe, D Denes, P DeNotaristefani, F De Salvo, A Diemoz, M van Dierendonck, D Di Lodovico, F Dionisi, C Dittmar, M Dominguez, A Doria, A Dova, MT Duchesneau, D Dufournand, D Duinker, P Duran, I Easo, S El Mamouni, H Engler, A Eppling, FJ Erne, FC Extermann, P Fabre, M Faccini, R Falagan, MA Falciano, S Favara, A Fay, J Fedin, O Felcini, M Ferguson, T Ferroni, F Fesefeldt, H Fiandrini, E Field, JH Filthaut, F Fisher, PH Fisk, I Forconi, G Fredj, L Freudenreich, K Furetta, C Galaktionov, Y Ganguli, SN Garcia-Abia, P Gataullin, M Gau, SS Gentile, S Gheordanescu, N Giagu, S Goldfarb, S Gong, ZF Gratta, G Gruenewald, MW van Gulik, R Gupta, VK Gurtu, A Gutay, LJ Haas, D Hartmann, B Hasan, A Hatzifotiadou, D Hebbeker, T Herve, A Hidas, P Hirschfelder, J Hofer, H Holzner, G Hoorani, H Hou, SR Iashvili, I Jin, BN Jones, LW de Jong, P Josa-Mutuberria, I Kasser, A Khan, RA Kamrad, D Kapustinsky, JS Kaur, M Kienzle-Focacci, MN Kim, D Kim, DH Kim, JK Kim, SC Kinnison, WW Kirkby, A Kirkby, D Kirkby, J Kiss, D Kittel, W Klimentov, A Konig, AC Kopp, A Korolko, I Koutsenko, V Kraemer, RW Krenz, W Kunin, A Lacentre, P de Guevara, PL Laktineh, I Landi, G Lapoint, C Lassila-Perini, K Laurikainen, P Lavorato, A Lebeau, M Lebedev, A Lebrun, P Lecomte, P Lecoq, P Le Coultre, P Lee, HJ Le Goff, JM Leiste, R Leonardi, E Levtchenko, P Li, C Lin, CH Lin, WT Linde, FL Lista, L Liu, ZA Lohmann, W Longo, E Lu, W Lu, YS Lubelsmeyer, K Luci, C Luckey, J Luminari, L Lustermann, W Ma, WG Maity, M Majumder, G Malgeri, L Malinin, A Mana, C Mangeol, D Marchesini, P Marian, G Martin, JP Marzano, F Massaro, GGG Mazumdar, K McNeil, RR Mele, S Merola, L Meschini, M Metzger, WJ von der Mey, M Mi, Y Migani, D Mihul, A Milcent, H Miabelli, G Mnich, J Molnar, P Monteleoni, B Moulik, T Mount, R Muanza, GS Muheim, F Muijs, AJM Nahn, S Napolitano, M Nessi-Tedaldi, F Newman, H Niessen, T Nippe, A Nisati, A Nowak, H Oh, YD Organtini, G Ostonen, R Palomares, C Pandoulas, D Paoletti, S Paolucci, P Park, HK Park, IH Pascale, G Passaleva, G Patricelli, S Paul, T Pauluzzi, M Paus, C Pauss, F Peach, D Pedace, M Pei, JJ Pensotti, S Perret-Gallix, D Petersen, B Petrak, S Pevsner, A Piccolo, D Pieri, M Piroue, PA Pistolesi, E Plyaskin, V Pohl, M Pojidaev, V Postema, H Pothier, J Produit, N Prokofiev, D Quartieri, J Rahal-Callot, G Raja, N Rancoita, PG Rattaggi, M Raven, G Razis, P Ren, D Rescigno, M Reucroft, S van Rhee, T Riemann, S Riles, K Robohm, A Rodin, J Roe, BP Romero, L Rosier-Lees, S Rosselet, P Roth, S Rubio, JA Ruschmeier, D Rykaczewski, H Sakar, S Salicio, J Sanchez, E Sanders, MP Sarakinos, ME Schafer, C Schegelsky, V Schmidt-Kaerst, S Schmitz, D Scholz, N Schopper, H Schotanus, DJ Schwenke, J Schwering, G Sciacca, C Sciarrino, D Servoli, L Shevchenko, S Shivarov, N Shoutko, V Shukla, J Shumilov, E Shvorob, A Siedenburg, T Son, D Smith, B Spillantini, P Steuer, M Stickland, DP Stone, A Stone, H Stoyanov, B Straessner, A Sudhakar, K Sultanov, G Sun, LZ Suter, H Swain, JD Szillasi, Z Tang, XW Tauscher, L Taylor, L Timmermans, C Ting, SCC Ting, SM Tonwar, SC Toth, J Tully, C Tung, KL Uchida, Y Ulbricht, J Valente, E Vesztergombi, G Vetlitsky, I Viertel, G Villa, S Vivargent, M Vlachos, S Vogel, H Vogt, H Vorobiev, I Vorobyov, AA Vorvolakos, A Wadhwa, M Wallraff, W Wang, JC Wang, XL Wang, ZM Weber, A Wu, SX Wynhoff, S Xu, ZZ Yang, BZ Yang, CG Yang, HJ Ye, JB Yeh, SC You, JM Zalite, A Zalite, Y Zemp, P Zeng, Y Zhang, ZP Zhu, GY Zhu, RY Zichichi, A Ziegler, F Zilizi, G TI Measurement of the e(+)e(-)-> Z -> b(b)over-bar forward-backward asymmetry and the B-0(B)over-bar(0) mixing parameter using prompt leptons SO PHYSICS LETTERS B LA English DT Article ID LUND MONTE-CARLO; JET FRAGMENTATION; E+E ANNIHILATION; L3; DETECTOR; DECAYS; PHYSICS; UPDATE AB The time-integrated B-0(B) over bar(0) mixing parameter and the forward-backward charge asymmetry in the process e(+)e(-) --> b (b) over bar are measured in hadronic Z events containing prompt muons or electrons, collected by the L3 experiment in the years 1990 to 1995. The total sample of 3.3 milion hadronic Z events with a mean centre-of-mass energy of 91.26 GeV yields: A(FB)(b) = 0.0960 +/- 0.0066(stat.) +/- 0.0033(sys.), chi(b) = 0.1192 +/- 0.0068(stat.)+/- 0.0051(sys.). This asymmetry measurement together with measurements at energies away from the Z pole energy yield a pole asymmetry and corresponding effective electroweak mixing angle of: A(FB)(0,b) = 0.1015 +/- 0.0064(stat.) +/- 0.0035(sys.), sin(theta)(2)W<(theta)over bar> = 0.2318 +/- 0.0013. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Rhein Westfal TH Aachen, Inst Phys 1, D-52056 Aachen, Germany. Rhein Westfal TH Aachen, Inst Phys 3, D-52056 Aachen, Germany. NIKHEF H, Natl Inst High Energy Phys, NL-1009 DB Amsterdam, Netherlands. Univ Amsterdam, NL-1009 DB Amsterdam, Netherlands. Univ Michigan, Ann Arbor, MI 48109 USA. CNRS, IN2P3, LAPP, Lab Annecy Le Vieux Phys Particules, F-74941 Annecy Le Vieux, France. Johns Hopkins Univ, Baltimore, MD 21218 USA. Univ Basel, Inst Phys, CH-4056 Basel, Switzerland. Louisiana State Univ, Baton Rouge, LA 70803 USA. Inst High Energy Phys, Beijing 100039, Peoples R China. Humboldt Univ, D-10099 Berlin, Germany. Univ Bologna, I-40126 Bologna, Italy. Ist Nazl Fis Nucl, Sez Bologna, I-40126 Bologna, Italy. Tata Inst Fundamental Res, Bombay 400005, Maharashtra, India. Northeastern Univ, Boston, MA 02115 USA. Inst Atom Phys, R-76900 Bucharest, Romania. Univ Bucharest, R-76900 Bucharest, Romania. Cent Res Inst Phys, H-1525 Budapest, Hungary. Hungarian Acad Sci, Cent Res Inst Phys, H-1525 Budapest 114, Hungary. MIT, Cambridge, MA 02139 USA. Ist Nazl Fis Nucl, Sez Firenze, I-50125 Florence, Italy. Univ Florence, I-50125 Florence, Italy. CERN, European Lab Particle Phys, CH-1211 Geneva 23, Switzerland. FBLJA Project, World Lab, CH-1211 Geneva 23, Switzerland. Univ Geneva, CH-1211 Geneva 4, Switzerland. Univ Sci & Technol China, Hefei 230029, Anhui, Peoples R China. Res Inst High Energy Phys, SEFT, SF-00014 Helsinki, Finland. Univ Lausanne, CH-1015 Lausanne, Switzerland. Ist Nazl Fis Nucl, Sez Lecce, I-73100 Lecce, Italy. Univ Lecce, I-73100 Lecce, Italy. Los Alamos Natl Lab, Los Alamos, NM 87544 USA. Univ Lyon 1, CNRS, IN2P3, Inst Phys Nucl Lyon, F-69622 Villeurbanne, France. CIEMAT, Ctr Invest Energet Medioambientales & Tecnol, E-28040 Madrid, Spain. Ist Nazl Fis Nucl, Sez Milano, I-20133 Milan, Italy. Inst Theoret & Expt Phys, Moscow 117259, Russia. Ist Nazl Fis Nucl, Sez Napoli, I-80125 Naples, Italy. Univ Naples Federico II, I-80125 Naples, Italy. Univ Cyprus, Dept Nat Sci, Nicosia, Cyprus. Univ Nijmegen, NL-6525 ED Nijmegen, Netherlands. Natl Inst Nucl Phys & High Energy Phys, NL-6525 ED Nijmegen, Netherlands. CALTECH, Pasadena, CA 91125 USA. Ist Nazl Fis Nucl, Sez Perugia, I-06100 Perugia, Italy. Univ Perugia, I-06100 Perugia, Italy. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Princeton Univ, Princeton, NJ 08544 USA. Ist Nazl Fis Nucl, Sez Roma, I-00185 Rome, Italy. Univ Roma La Sapienza, I-00185 Rome, Italy. Inst Nucl Phys, St Petersburg, Russia. Univ Salerno, I-84100 Salerno, Italy. Ist Nazl Fis Nucl, I-84100 Salerno, Italy. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Santiago, Dept Fis Particulas Elementales, E-15706 Santiago, Spain. Bulgarian Acad Sci, Cent Lab Mech & Instrumentat, BU-1113 Sofia, Bulgaria. Korea Adv Inst Sci & Technol, Ctr High Energy Phys, Taejon 305701, South Korea. Univ Alabama, University, AL 35486 USA. Univ Utrecht, NL-3584 CB Utrecht, Netherlands. NIKHEF H, NL-3584 CB Utrecht, Netherlands. Purdue Univ, W Lafayette, IN 47907 USA. Paul Scherrer Inst, CH-5232 Villigen, Switzerland. DESY, Inst Hochenergiephys, D-15738 Zeuthen, Germany. Swiss Fed Inst Technol, CH-8093 Zurich, Switzerland. Univ Hamburg, D-22761 Hamburg, Germany. Natl Cent Univ, Chungli 32054, Taiwan. RP Rhein Westfal TH Aachen, Inst Phys 1, D-52056 Aachen, Germany. RI Sanchez, Eusebio/H-5228-2015; Duran, Ignacio/H-7254-2015; Rancoita, Pier Giorgio/J-9896-2015; Hoorani, Hafeez/D-1791-2013; Palomares, Carmen/H-7783-2015; Fedin, Oleg/H-6753-2016; Roth, Stefan/J-2757-2016; Di Lodovico, Francesca/L-9109-2016; Yang, Haijun/O-1055-2015; Achard, Pablo/C-2983-2009; Fiandrini, Emanuele/C-4549-2008; Lista, Luca/C-5719-2008; Kirkby, Jasper/A-4973-2012; Servoli, Leonello/E-6766-2012; bertucci, bruna/J-5237-2012; Cavallo, Nicola/F-8913-2012; Cerrada, Marcos/J-6934-2014; Josa, Isabel/K-5184-2014; de la Cruz, Begona/K-7552-2014; Vogel, Helmut/N-8882-2014; Ferguson, Thomas/O-3444-2014; Berdugo, Javier/A-2858-2015 OI Sanchez, Eusebio/0000-0002-9646-8198; Rancoita, Pier Giorgio/0000-0002-1990-4283; Palomares, Carmen/0000-0003-4374-9065; Roth, Stefan/0000-0003-3616-2223; Di Lodovico, Francesca/0000-0003-3952-2175; Achard, Pablo/0000-0002-4865-3196; Kirkby, Jasper/0000-0003-2341-9069; Servoli, Leonello/0000-0003-1725-9185; Cerrada, Marcos/0000-0003-0112-1691; Vogel, Helmut/0000-0002-6109-3023; Ferguson, Thomas/0000-0001-5822-3731; Berdugo, Javier/0000-0002-7911-8532 NR 31 TC 19 Z9 19 U1 0 U2 2 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 FEB 18 PY 1999 VL 448 IS 1-2 BP 152 EP 162 DI 10.1016/S0370-2693(98)01601-3 PG 11 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 173NG UT WOS:000078986200022 ER PT J AU Fornstedt, T Gotmar, G Andersson, M Guiochon, G AF Fornstedt, T Gotmar, G Andersson, M Guiochon, G TI Dependence on the mobile-phase pH of the adsorption behavior of propranolol enantiomers on a cellulase protein used as the chiral selector SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID HUMAN SERUM-ALBUMIN; CHROMATOGRAPHIC BAND PROFILES; CBH-I-SILICA; LIQUID-CHROMATOGRAPHY; STATIONARY-PHASE; ALPHA-1-ACID GLYCOPROTEIN; IMMOBILIZED CELLULASE; CELLOBIOHYDROLASE-I; TRICHODERMA-REESEI; BETA-BLOCKERS AB We reported previously on the unusual thermodynamic characteristics of the enantioselective interactions between the enantiomers of the beta-blocker propranolol and the protein cellobiohydrolase I immobilized on silica. The adsorption of the more retained enantiomer, (S)-propranolol, is endothermic while that of the (R)-propranolol is exothermic. This causes a rapid increase of the selectivity factor with increasing temperature. In this work, we study the complex dependence of the selectivity factor on the pH of the solvent. We determined the equilibrium isotherms of (R)- and (S)-propranolol in a wide concentration range (0.25 mu M to 1.1 mM) at six different mobile-phase pHs (4.7, 5.0, 5.2, 5.5,5.7, and 6.0) and fitted the data obtained to the bl-langmuir model. This gave the saturation capacity and the binding constant of the nonselective contribution for the two enantiomers. It also gave these parameters for the enantioselective contributions of each of them. The dependence of these parameters on the pH is discussed and interpreted in terms of the retention mechanism. Our conclusions are in excellent agreement with recent, independent results on the structure of the protein obtained by X-ray crystallography. C1 Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Biomed Ctr, Dept Pharm, S-75123 Uppsala, Sweden. 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. OI Fornstedt, Torgny/0000-0002-7123-2066 NR 34 TC 73 Z9 74 U1 2 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD FEB 17 PY 1999 VL 121 IS 6 BP 1164 EP 1174 DI 10.1021/ja9831296 PG 11 WC Chemistry, Multidisciplinary SC Chemistry GA 168CY UT WOS:000078674500007 ER PT J AU George, GN Hilton, J Temple, C Prince, RC Rajagopalan, KV AF George, GN Hilton, J Temple, C Prince, RC Rajagopalan, KV TI Structure of the molybdenum site of dimethyl sulfoxide reductase SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID X-RAY-ABSORPTION; ELECTRON-PARAMAGNETIC-RESONANCE; BOND-VALENCE PARAMETERS; F-SP DENITRIFICANS; RHODOBACTER-SPHAEROIDES; CRYSTAL-STRUCTURE; XANTHINE-OXIDASE; DMSO REDUCTASE; ESCHERICHIA-COLI; NITRATE REDUCTASE AB Molybdenum K-edge X-ray absorption and Mo(V) electron paramagentic resonance (EPR) spectroscopies have been used to probe the metal coordination in oxidized and reduced forms of both wildtype and a site-directed mutant of Rhodobacter sphaeroides dimethyl sulfoxide (DMSO) reductase, We confirm our earlier findings (George, G. N.; Hilton, J.; Rajagopalan, K. V. J. Am. Chem. Sec. 1996, 118, 1113-1117) that the molybdenum site of the oxidized Mo(VI) enzyme possesses one terminal oxygen ligand (Mo=O) at 1.68 Angstrom, four thiolate ligands at: 2.44 Angstrom, and one oxygen at 1.92 Angstrom and that the dithionite-reduced Mo(IV) enzyme possesses a desoxo species with three or:four Mo-S at 2.33 Angstrom and two different Mo-O ligands at 2.16 and 1.92 Angstrom. Mo(V) EPR indicates the presence of one exchangeable oxygen ligand, most likely an Mo-OH, in the signal-giving species; probably originating from the Mo=O of the oxidized enzyme (E-m8.5(IV/V) + 37 mV, E-m8.5(V/VI) = +83 mV). The addition of dimethyl sulfide,in the reverse of the physiological reaction, reduces the enzyme. In this form, the enzyme contains a desoxo active site with four Mo-S at 2.36 If and two different Mo-O ligands at 1.94 and 2.14 Angstrom. Recombinant wild-type R. sphaeroides DMSO reductase expressed in Escherichia coli. initially has a dioxo structure (two Mo=O at 1.72 Angstrom and four Mo-S at 2.48 Angstrom) but assumes the wild-type Mo(VI) structure after a cycle of reduction and reoxidation. The site-directed Ser147-->Cys mutant possesses a monooxo active site in the oxidized state (Mo=O at 1.70 Angstrom) with five sulfur ligands (at 2.40 Angstrom), consistent with cysteine 147 coordination to Mo. The dithionite reduced form of the mutant possesses a desoxo site also with five. Mo-S ligands (at 2.37 Angstrom) and one Mo-O at 2.12 Angstrom. The variant has substantially different Mo(V) EPR and electrochemistry (E-m8.5(IV/V) -43 mV, E-m8.5(V/VI) = +106 mV). The active-site structure and catalytic mechanism of DMSO reductase are discussed in the light of the-se results. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. Duke Univ, Sch Med, Dept Biochem, Durham, NC 27710 USA. Exxon Res & Engn Co, Annandale, NJ 08801 USA. RP George, GN (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, POB 4349,MS 69, Stanford, CA 94309 USA. RI George, Graham/E-3290-2013 NR 72 TC 122 Z9 122 U1 3 U2 18 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD FEB 17 PY 1999 VL 121 IS 6 BP 1256 EP 1266 DI 10.1021/ja982843k PG 11 WC Chemistry, Multidisciplinary SC Chemistry GA 168CY UT WOS:000078674500018 ER PT J AU Klooster, WT Brammer, L Schaverien, CJ Budzelaar, PHM AF Klooster, WT Brammer, L Schaverien, CJ Budzelaar, PHM TI C-H bonds are not elongated by coordination to lanthanide metals: Single-crystal neutron diffraction structures of (C5Me5)Y((OC6H3Bu2)-Bu-t)CH(SiMe3)(2) at 20 K and (C5Me5)La{CH(SiMe3)(2)}(2) at 15 K SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID HIGHLY REACTIVE ORGANOLANTHANIDES; X-RAY; ORGANOMETALLIC COMPOUNDS; NUMERICAL-INTEGRATION; CHEMISTRY; COMPLEXES; POLYMERIZATION; HYDROCARBYLS; DERIVATIVES; HYDRIDES C1 Univ Missouri, Dept Chem, St Louis, MO 63121 USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Shell Res & Technol Ctr Amsterdam, NL-1030 BN Amsterdam, Netherlands. Catholic Univ Nijmegen, Dept Inorgan Chem, NL-6525 ED Nijmegen, Netherlands. RP Univ Missouri, Dept Chem, St Louis, MO 63121 USA. EM lee.brammer@umsl.edu; Colin.J.Schaverien@opc.shell.com; budz@sci.kun.nl NR 23 TC 97 Z9 97 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 FEB 17 PY 1999 VL 121 IS 6 BP 1381 EP 1382 DI 10.1021/ja983068b PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 168CY UT WOS:000078674500032 ER PT J AU Zhao, JK Wang, JT Chen, DJ Peterson, SR Trewhella, J AF Zhao, JK Wang, JT Chen, DJ Peterson, SR Trewhella, J TI The solution structure of the DNA double-stranded break repair protein Ku and its complex with DNA: A neutron contrast variation study SO BIOCHEMISTRY LA English DT Article ID ANGLE-SCATTERING-DATA; LIGHT-CHAIN KINASE; RNA POLYMERASE-II; V(D)J RECOMBINATION; TROPONIN-C; X-RAY; BINDING; ENDS; CALMODULIN; ANTIGEN AB Small-angle X-ray and neutron scattering with contrast variation has been used to study the structure of the DNA targeting component (Ku) of the DNA-dependent protein kinase and its complex with DNA. The Ku protein in solution has the approximate shape of a prolate ellipsoid with semi-axes of 24, 43, and 89 Angstrom. In the presence of a minimal-length DNA binding sequence (a 24-base-pair duplex DNA), a 1:1 Ku/DNA complex forms. This 1:1 stoichiometry is observed when either the Ku or the DNA is in excess. Analysis of the contrast variation data on Ku complexed with either the 24-mer duplex DNA or a slightly longer 30-mer duplex DNA shows that both the DNA and Ku structures have the same overall conformations within the 1:1 complex as the uncomplexed components. The separation of the centers-of-mass for the Ku/24-mer DNA complex is 46 Angstrom, while that for the Ku/30-mer DNA is 56 Angstrom. The DNA binds within what appears to be a preformed channel that penetrates deeply into the Ku protein such that the entire length of the 24-mer DNA spans the protein, The slightly longer 30-mer binds in a similar fashion, but with its extra length protruding from the protein envelop. The scattering data are consistent with the idea that the Ku "threads" onto the duplex DNA via a channel that can completely bury approximately 24 base pairs. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. RP Trewhella, J (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, POB 1663, Los Alamos, NM 87545 USA. EM jtrewhella@lanl.gov RI Zhao, Jinkui/B-7872-2013; OI Zhao, Jinkui/0000-0002-7756-1952; Trewhella, Jill/0000-0002-8555-6766 FU NCI NIH HHS [CA50519] NR 43 TC 12 Z9 12 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 FEB 16 PY 1999 VL 38 IS 7 BP 2152 EP 2159 DI 10.1021/bi9825246 PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 175VZ UT WOS:000079117500022 PM 10026299 ER PT J AU Hart, PJ Balbirnie, MM Ogihara, NL Nersissian, AM Weiss, MS Valentine, JS Eisenberg, D AF Hart, PJ Balbirnie, MM Ogihara, NL Nersissian, AM Weiss, MS Valentine, JS Eisenberg, D TI A structure-based mechanism for copper-zinc seperoxide dismutase SO BIOCHEMISTRY LA English DT Article ID BOVINE SUPEROXIDE-DISMUTASE; AMYOTROPHIC-LATERAL-SCLEROSIS; CRYSTAL-STRUCTURE; X-RAY; ANGSTROM RESOLUTION; IMIDAZOLATE BRIDGE; PULSE-RADIOLYSIS; ANION BINDING; REFINEMENT; SITES AB A reaction cycle is proposed for the mechanism of copper-zinc superoxide dismutase (CuZnSOD) that involves inner sphere electron transfer from superoxide to Cu(II) in one portion of the cycle and outer sphere electron transfer from Cu(I) to superoxide in the other portion of the cycle. This mechanism is based on three yeast CuZnSOD structures determined by X-ray crystallography together with many other observations. The new structures reported here are (1) wild type under 15 atm of oxygen pressure, (2) wild type in the presence of azide, and (3) the His48Cys mutant, Final R-values for the three structures are respectively 20.0%, 17.3%, and 20.9%. Comparison of these three new structures to the wild-type yeast Cu(I)ZnSOD model, which has a broken imidazolate bridge, reveals the following: (i) The protein backbones (the "SOD rack") remain essentially unchanged. (ii) A pressure of 15 atm of oxygen causes a displacement of the copper ion 0.37 Angstrom from its Cu(I) position in the trigonal plane formed by His46, His48, and His120. The displacement is perpendicular to this plane and toward the NE2 atom of His63 and is accompanied by elongated copper electron density in the direction of the displacement suggestive of two copper positions in the crystal. The copper geometry remains three coordinate, but the His48-Cu band distance increases by 0.18 Angstrom. (iii) Azide binding also causes a displacement of the copper toward His63 such that it moves 1.28 Angstrom from the wild-type Cu(I) position, but unlike the effect of 15 atm of oxygen, there is no two-state character, The geometry becomes five-coordinate square pyramidal, and the His63 imidazolate bridge re-forms. The His48-Cu distance increases by 0.70 Angstrom, suggesting that His48 becomes an axial ligand, (iv) The His63 imidazole ring tilts upon 15 atm of oxygen treatment and azide binding. Its NE2 atom moves toward the trigonal plane by 0.28 and 0.66 Angstrom respectively, in these structures. (v) The replacement of His48 by Cys, which does not bind copper, results in a five-coordinate square pyramidal, bridge-intact copper geometry with a novel chloride ligand, Combining results from these and other CuZnSOD crystal structures, we offer the outlines of a structure-based cyclic mechanism. C1 Univ Calif Los Angeles, DOE Lab Struct Biol & Mol Med, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Biochem & Chem, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Biol Chem, Los Angeles, CA 90095 USA. RP Valentine, JS (reprint author), Univ Calif Los Angeles, DOE Lab Struct Biol & Mol Med, Los Angeles, CA 90095 USA. RI Valentine, Joan/B-6665-2008; Weiss, Manfred/B-6857-2013 OI Valentine, Joan/0000-0002-7174-925X; FU NIGMS NIH HHS [GM28222, GM31299] NR 65 TC 132 Z9 134 U1 1 U2 15 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD FEB 16 PY 1999 VL 38 IS 7 BP 2167 EP 2178 DI 10.1021/bi982284u PG 12 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 175VZ UT WOS:000079117500024 PM 10026301 ER PT J AU Johal, MS Parikh, AN Lee, Y Casson, JL Foster, L Swanson, BI McBranch, DW Li, DQ Robinson, JM AF Johal, MS Parikh, AN Lee, Y Casson, JL Foster, L Swanson, BI McBranch, DW Li, DQ Robinson, JM TI Study of the conformational structure and cluster formation in a Langmuir-Blodgett film using second harmonic generation, second harmonic microscopy, and FTIR spectroscopy SO LANGMUIR LA English DT Article ID AIR-WATER-INTERFACE; 2ND-HARMONIC GENERATION; PHASE-TRANSITION; SUM-FREQUENCY; THIN-FILMS; MONOLAYERS; BEHAVIOR; DYE; ORIENTATION; SURFACES AB Nonlinear second harmonic generation (SHG), second harmonic microscopy (SHM), and infrared spectroscopy are used to determine the structural and optical properties of the Langmuir-Blodgett (LB) monolayer assemblies of NLO-active, 4-eicosyloxo-(E)-stilbazolium iodide (4-EOSI) on a glass substrate. The packing characteristics of the pretransferred interfacial films are determined using pi-A isotherm measurements. The molecular coverage of the transferred films is determined by ellipsometry. The films formed on both sides of the glass substrate show substantial second harmonic (SH) conversion from p-polarized 1064 nm fundamental excitation. The SHG and FTIR measurements imply that the single LB layer on glass is composed of oriented clusters of 4-EOSI molecules that are laterally discontinuous. Ordered clusters up to 40 mu m in diameter are directly observed using SHM. Subsequent LB transfers using the same 4-EOSI molecule or an amphiphile of comparable chain-length (eicosanoic acid) fill in the unoccupied vacancies in the first layer. The magnitude of the dominant element of the nonlinear susceptibility and the average molecular orientation angle of the chromophore are determined by modeling the characteristic SHG Maker fringes. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Johal, MS (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, POB 1663, Los Alamos, NM 87545 USA. RI PARIKH, ATUL/D-2243-2014 OI PARIKH, ATUL/0000-0002-5927-4968 NR 46 TC 29 Z9 29 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD FEB 16 PY 1999 VL 15 IS 4 BP 1275 EP 1282 DI 10.1021/la981072v PG 8 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 168GB UT WOS:000078682400056 ER PT J AU Zhuang, GR Chen, YF Ross, PN AF Zhuang, GR Chen, YF Ross, PN TI The reaction of lithium with dimethyl carbonate and diethyl carbonate in ultrahigh vacuum studies by X-ray photoemission spectroscopy SO LANGMUIR LA English DT Article ID PROPYLENE CARBONATE; XPS; LI; TETRAHYDROFURAN AB The reaction of dimethyl carbonate (DMC) and diethyl carbonate (DEC) with clean metallic lithium in ultrahigh vacuum was studied by the use of X-ray photoelectron spectroscopy with the temperature-programmed reaction methodology. Both molecules are of interest as solvents in ambient-temperature lithium batteries. The solvent molecules were condensed onto the surface of an evaporated lithium film at 120 K, and spectra were collected as the sample was warmed in ca. 25 to 30-K increments. The reaction of either DMC or DEC with. lithium was initiated at 180 K, a temperature much lower than their bulk melting temperatures, producing lithium methyl carbonate, methyllithium and lithium ethyl carbonate, and ethyllithium, respectively. At temperatures greater than 270-300 K, the lithium alkyl carbonates start to decompose with Li2O, elemental carbon, and alkyllithium as products on the surface. Both DMC and DEC are more reactive toward metallic Li than another carbonate solvent, propylene carbonate, which we have studied by the same methodology. Because methyl and ethyllithium are highly soluble in the parent solvent, electrodeposited Li is predicted to have poor stability in an electrolyte composed of either DMC or DEC. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Ross, PN (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Chem Sci, Berkeley, CA 94720 USA. EM pnross@csa1.lbl.gov NR 14 TC 38 Z9 38 U1 1 U2 17 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD FEB 16 PY 1999 VL 15 IS 4 BP 1470 EP 1479 DI 10.1021/la980454y PG 10 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 168GB UT WOS:000078682400083 ER PT J AU Pande, VS Rokhsar, DS AF Pande, VS Rokhsar, DS TI Folding pathway of a lattice model for proteins SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID MOLTEN GLOBULE INTERMEDIATE; TRANSITION-STATE; KINETICS; THERMODYNAMICS; SIMULATIONS; MECHANISMS; MOLECULES; FUNNELS; DOMAIN AB The folding of a protein-like heteropolymer is studied by using direct simulation of a lattice model that folds rapidly to a well-defined "native" structure. The details of each molecular folding event depend on the random initial conformation as well as the random thermal fluctuations of the polymer. By analyzing the statistical properties of hundreds of folding events, a classical folding "pathway" for such a polymer is found that includes partially folded, on-pathway intermediates that are shown to be metastable equilibrium states of the polymer. These results are discussed in the context of the "classical" and "new" views of folding. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Phys Biosci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RP Rokhsar, DS (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Phys Biosci, Berkeley, CA 94720 USA. EM rokhsar@physics.berkeley.edu NR 46 TC 104 Z9 105 U1 0 U2 3 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD FEB 16 PY 1999 VL 96 IS 4 BP 1273 EP 1278 DI 10.1073/pnas.96.4.1273 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 168ND UT WOS:000078698400022 PM 9990014 ER PT J AU Kurimasa, A Ouyang, H Dong, LJ Wang, S Li, XL Cordon-Cardo, C Chen, DJ Li, GC AF Kurimasa, A Ouyang, H Dong, LJ Wang, S Li, XL Cordon-Cardo, C Chen, DJ Li, GC TI Catalytic subunit of DNA-dependent protein kinase: Impact on lymphocyte development and tumorigenesis SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID SEVERE COMBINED IMMUNODEFICIENCY; V(D)J RECOMBINATION; NONSENSE MUTATION; ABERRANT CRYPTS; STRANDED-DNA; REPAIR; MICE; MOUSE; DEFECTS; COMPLEX AB The DNA-dependent protein kinase (DNA-PK) consists of a heterodimer DNA-binding complex, Ku70 and Ku80, and a large catalytic subunit, DNA-PKcs, To examine the role of DNA-PKcs in lymphocyte development, radiation sensitivity, and tumorigenesis, we disrupted the mouse DNA-PKcs by homologous recombination. DNA-PKcs-null mice exhibit neither growth retardation nor a high frequency of T cell lymphoma development, but show severe immunodeficiency and radiation hypersensitivity. In contrast to the Ku70-/- and Ku80-/- phenotype, DNA-PKcs-null mice are blocked for V(D)J coding but not for signal-end joint formation. Furthermore, inactivation of DNA-PKcs leads to hyperplasia and dysplasia of the intestinal mucosa and production of aberrant crypt foci, suggesting a novel role of DNA-PKcs in tumor suppression. C1 Mem Sloan Kettering Canc Ctr, Dept Radiat Oncol, New York, NY 10021 USA. Mem Sloan Kettering Canc Ctr, Dept Phys Med, New York, NY 10021 USA. Mem Sloan Kettering Canc Ctr, Dept Pathol, New York, NY 10021 USA. Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. RP Li, GC (reprint author), Mem Sloan Kettering Canc Ctr, Dept Radiat Oncol, Box 72,1275 York Ave, New York, NY 10021 USA. EM g-li@ski.mskcc.org FU NCI NIH HHS [R01 CA050519, T32 CA061801, R37 CA050519, R01 CA056909, CA-78497, CA-56909, CA-31397] NR 32 TC 125 Z9 133 U1 0 U2 0 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD FEB 16 PY 1999 VL 96 IS 4 BP 1403 EP 1408 DI 10.1073/pnas.96.4.1403 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 168ND UT WOS:000078698400044 PM 9990036 ER PT J AU Bryan, JC Bunick, GJ Sachleben, RA AF Bryan, JC Bunick, GJ Sachleben, RA TI Tetrabenzo-24-crown-8 SO ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS LA English DT Article ID ETHERS AB The structure of tetrabenzo-24-crown-8, C32H32O8, does not exhibit a binding cavity for alkali metal ions, but is collapsed in on itself. The conformation may be a result of inter- and intramolecular hydrogen bonding. The molecule lies on an inversion center. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. RP Bryan, JC (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. NR 16 TC 12 Z9 12 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 FEB 15 PY 1999 VL 55 BP 250 EP 252 DI 10.1107/S0108270198012700 PN 2 PG 3 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 175AN UT WOS:000079068900045 ER PT J AU Zhou, SL Edwards, AG Cook, KD Van Berkel, GJ AF Zhou, SL Edwards, AG Cook, KD Van Berkel, GJ TI Investigation of the electrospray plume by laser-induced fluorescence spectroscopy SO ANALYTICAL CHEMISTRY LA English DT Article ID IONIZATION-MASS-SPECTROMETRY; CHARGE-STATE DISTRIBUTIONS; POSITIVE-ION; AMINO-ACIDS; PROTEINS; SPECTRA; PH; GAS; POLYPEPTIDES; DEPENDENCE AB Laser-induced fluorescence spectroscopy has been employed to probe the electrospray plume through measurement of the emission spectra of fluorescent dyes in the spray stream. The system is evaluated with respect to sensitivity and reproducibility using solutions of Eosin Y under typical electrospray conditions. Application of the technique for monitoring spray-induced pH changes is demonstrated using fluorescence signals from a pH-sensitive fluorophore, carboxyseminaphthorhodafluor-1 (C.SNARF-1). To our knowledge, this is the first direct measurement of pH within the electrospray plume. C1 Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Cook, KD (reprint author), Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. EM kcook@utk.edu OI Cook, Kelsey/0000-0003-2053-3309 NR 43 TC 47 Z9 47 U1 2 U2 15 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 FEB 15 PY 1999 VL 71 IS 4 BP 769 EP 776 DI 10.1021/ac981259r PG 8 WC Chemistry, Analytical SC Chemistry GA 166UG UT WOS:000078595100002 ER PT J AU Miyabe, K Guiochon, G AF Miyabe, K Guiochon, G TI Analysis of surface diffusion phenomena in reversed-phase liquid chromatography SO ANALYTICAL CHEMISTRY LA English DT Article ID OCTADECYLSILYL-SILICA GEL; ADSORPTION CHARACTERISTICS; LATERAL DIFFUSION; ACTIVATED CARBON; ADSORBED GASES; FILLED PORES; COEFFICIENT; DEPENDENCE AB Surface diffusion data obtained for a reversed-phase liquid chromatographic system (octadecylsilyl silica gel and a 70/30 (v/v) methanol/water solution) were analyzed in relation to their molecular diffusivity (D-m). The adsortate-adsorbent interactions between the studied compounds and the stationary phase were taken into account. The surface diffusion coefficient (D-s) depends on the mobile-phase composition, especially on the nature and concentration of the organic modifiers. Differences between the values of D-s measured under various conditions stem probably from differences in D-m. It also seems that D-s tends toward D-m with decreasing retention factor. The surface diffusion mechanism was assumed to be a restricted molecular diffusion in a potential held of adsorption. A restriction energy for this diffusion (E-r) was introduced to correlate D-s with D-m. The ratio of E-r to the isosteric heat of adsorption (-Q(st))was found to be nearly constant, irrespective of the retention factor, with an average value of 0.32 for our phase system. An estimation procedure for D-s using the enthalpy-entropy compensation effect for the adsorption equilibrium is proposed. From the adsorption equilibrium constant at 298 K only, D-s could be estimated at different temperatures with an error less than similar to 50%. 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 34 TC 47 Z9 47 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 FEB 15 PY 1999 VL 71 IS 4 BP 889 EP 896 DI 10.1021/ac9809027 PG 8 WC Chemistry, Analytical SC Chemistry GA 166UG UT WOS:000078595100019 ER PT J AU Giudice, GE Kuksenkov, DV Temkin, H Lear, KL AF Giudice, GE Kuksenkov, DV Temkin, H Lear, KL TI Differential carrier lifetime in oxide-confined vertical cavity lasers obtained from electrical impedance measurements SO APPLIED PHYSICS LETTERS LA English DT Article ID QUANTUM-WELL LASERS AB Differential carrier lifetime measurements were performed on index-guided oxide-confined vertical cavity surface emitting lasers operating at 980 nm. Lifetimes were extracted from laser impedance measurements at subthreshold currents, with device size as a parameter, using a simple small-signal model. The carrier lifetimes ranged from 21 ns at 9 mu A,to about 1 ns at a bias close to threshold. For a 6X6 mu m(2) oxide aperture device the threshold carrier density was n(th)similar to 2X10(18) cm(-3). The effect of carrier diffusion was also considered. An ambipolar diffusion coefficient of D similar to 11 cm(2) s(-1) was obtained. (C) 1999 American Institute of Physics. [S0003-6951(99)00507-0]. C1 Texas Tech Univ, Dept Elect Engn, Lubbock, TX 79409 USA. MicroOpt Devices Inc, Albuquerque, NM 87109 USA. Sandia Natl Labs, Albuquerque, NM 88448 USA. RP Giudice, GE (reprint author), Texas Tech Univ, Dept Elect Engn, Lubbock, TX 79409 USA. NR 15 TC 9 Z9 9 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 15 PY 1999 VL 74 IS 7 BP 899 EP 901 DI 10.1063/1.123403 PG 3 WC Physics, Applied SC Physics GA 166JA UT WOS:000078571400001 ER PT J AU Mahan, GD Bartkowiak, M AF Mahan, GD Bartkowiak, M TI Wiedemann-Franz law at boundaries SO APPLIED PHYSICS LETTERS LA English DT Article ID THERMOELECTRIC FIGURE; FINITE DIMENSIONS; MERIT; SEMICONDUCTORS; RESISTANCE AB The full equations are derived for the resistances to the transport of heat and electricity through boundaries of thermoelectrics. We show that the boundary resistances of heat and electricity are proportional. This relationship is a boundary form of the Wiedemann-Franz law. We also show there is a boundary Seebeck coefficient. (C) 1999 American Institute of Physics. [S0003-6951(99)03907-8]. C1 Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Mahan, GD (reprint author), Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. EM gmahan@utk.edu NR 23 TC 69 Z9 70 U1 3 U2 27 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 15 PY 1999 VL 74 IS 7 BP 953 EP 954 DI 10.1063/1.123420 PG 2 WC Physics, Applied SC Physics GA 166JA UT WOS:000078571400019 ER PT J AU Xu, J Roth, EG Holland, OW Mills, AP Suzuki, R AF Xu, J Roth, EG Holland, OW Mills, AP Suzuki, R TI Vacancy defects in solid-phase epitaxial grown layers of self-implanted Si SO APPLIED PHYSICS LETTERS LA English DT Article ID TRANSIENT ENHANCED DIFFUSION; SILICON; TEMPERATURE; DEPENDENCE; POSITRONS; ENERGY; BORON AB A method for preparing shallow dopant distributions via solid-phase epitaxial growth (SPEG) following amorphization by low-energy Si self-ion implantation leaves defects that can lead to unwanted dopant impurity diffusion. The double implant method for SPEG [O. W. Holland et al., J. Electron. Mater. 25, 99 (1996)] uses both low- and high-energy Si self-ion implantation to remove most of the interstitials. Nevertheless, we find that measurable crystalline imperfections remain following the SPEG annealing step. Measurements of defect profiles using variable-energy positron spectroscopy show that there are divacancy-impurity complexes in the SPEG layer and V-6 and larger vacancy clusters near the SPEG-crystalline interface. These measurements should be useful for modeling the diffusion of dopant atoms and for fine tuning the double implant parameters. (C) 1999 American Institute of Physics. [S0003-6951(99)01707-6]. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. AT&T Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. Electrotech Lab, Ibaraki, Osaka 305, Japan. RP Xu, J (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA. NR 15 TC 29 Z9 29 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 15 PY 1999 VL 74 IS 7 BP 997 EP 999 DI 10.1063/1.123453 PG 3 WC Physics, Applied SC Physics GA 166JA UT WOS:000078571400034 ER PT J AU Rithidech, KN Cronkite, EP Bond, VP AF Rithidech, KN Cronkite, EP Bond, VP TI Advantages of the CBA mouse in leukemogenesis research SO BLOOD CELLS MOLECULES AND DISEASES LA English DT Article DE leukemogenesis; radiation; benzene; cytogenetics ID ACUTE MYELOID-LEUKEMIA; IN-SITU HYBRIDIZATION; ACUTE LYMPHOBLASTIC-LEUKEMIA; ACUTE MYELOBLASTIC-LEUKEMIA; T-CELL LEUKEMIA; CHROMOSOMAL-ABNORMALITIES; INHALED BENZENE; FRAGILE SITES; MICE; GENE AB The objectives of this review are to: (a) demonstrate that the male CBA/Ca mouse has several characteristics that make it an excellent animal for the study of leukemogenesis, (b) show that several of the genetic abnormalities observed in the male CBA/Ca mouse during the development of radiation induced acute myeloid leukemia (AML) are syntenic with those frequently detected in patients with myeloid disorders such as myelodysplastic syndrome and AML, (c) illustrate that leukemia-related chromosomal lesions are the indicators for high risk individuals. C1 SUNY Stony Brook, Dept Pathol, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. Washington State Univ, Richland, WA 99352 USA. RP Rithidech, KN (reprint author), SUNY Stony Brook, Dept Pathol, BHS T9, Stony Brook, NY 11794 USA. NR 69 TC 28 Z9 29 U1 2 U2 2 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1079-9796 J9 BLOOD CELL MOL DIS JI Blood Cells Mol. Dis. PD FEB 15 PY 1999 VL 25 IS 3 BP 38 EP 46 DI 10.1006/bcmd.1999.0225 PG 9 WC Hematology SC Hematology GA 167VM UT WOS:000078654600001 PM 10349512 ER PT J AU Zhang, H Bartlett, RJ AF Zhang, H Bartlett, RJ TI Light-induced oxidation of aqueous chromium(III) in the presence of iron(III) SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID REDUCTION; KINETICS; CHEMISTRY; SOILS AB Oxidation of Cr(III) to toxic Cr(VI) by Mn(IV) or Mn(III) species has been identified as probably the only important oxidation pathway in soils, aquatic bodies, and atmospheric environments. We observed ready oxidation of Cr(III) in Fe(III) solutions in light at pH 3.2-4.4. Further kinetic study of this oxidation was performed in sunlight as well as in black light under controlled conditions (e.g., pH 3.2, 20 degrees C). Quantum yields of Cr(VI) formation at 356 nm were 0.020-0.046 for initial levels of 50-800 mu M Cr(III) and 200 mu M Fe(III). The Cr(VI) formation reached steady state in 0.5 h (6 mu M, [Cr(III)](0): 50 mu M; 10 mu M, [Cr(III)](0): 200 mu M; [Fe(III)](0): 200 mu M). The best linearity found only for log[Cr(lll)] vs t in the first 1 or 1.5 min of the reaction suggests apparent first-order kinetics for the disappearance of Cr(lll) at 356 nm over the period; afterward, it failed to comply with any regular rate law, The Cr(lll) oxidation decreased at high initial levels of Cr(lll) or Fe(lll) and upon removal of O-2, and it was found to be very limited at pH <2.5 or pH >5.0. Cr(III) was hypothesized to be oxidized to Cr(VI) by . OH radicals from photolysis of FeOH2+ complexes (estimated k .(OH+Cr(III)) = 8.3 X 10(7) M-1 s(-1)); Cr(VI) also was reduced by the formed Fe(ll) and intermediates such as HO2. This study suggests that light-induced oxidation of aqueous Cr(III) in the presence of Fe(lll) would be one potential pathway for the oxidation of Cr(lll) to toxic Cr(VI), more possibly in atmospheric waters or in acidic surface waters with low dissolved organic carbon content; it would not be expected to occur in surface soils because of their universal association with organic carbon. C1 Univ Vermont, Dept Plant & Soil Sci, Burlington, VT 05405 USA. RP Zhang, H (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. NR 32 TC 37 Z9 40 U1 3 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD FEB 15 PY 1999 VL 33 IS 4 BP 588 EP 594 DI 10.1021/es980608w PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 166VN UT WOS:000078598600011 ER PT J AU Zhang, PC Ryan, JA AF Zhang, PC Ryan, JA TI Formation of chloropyromorphite from galena (PbS) in the presence of hydroxyapatite SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID LEAD IMMOBILIZATION; AQUEOUS-SOLUTIONS; CONTAMINATED SOILS; TRACE-METALS; APATITE; ORTHOPHOSPHATES; PYROMORPHITE; DISSOLUTION; PHOSPHATES; STABILITY AB Transformation of unstable lead [Pb(ll)] forms into sparingly soluble pyromorphite [Pb-5(PO4)(3)(OH, Cl, F, ...)] by the addition of phosphate to Pb-contaminated soil has been proposed as a remediation technology to reduce the mobility and bioavailability of Pb. Galena, an insoluble lead sulfide mineral (PbS) frequently found in mining wastes, becomes unstable upon exposure to oxidizing conditions causing it to become a source of liable Pb forms in soils. Thus, a galena ore was reacted with synthetic hydroxyapatite [Ca-5(PO4)(3)OH] under various pH conditions to determine the formation rate of pyromorphite and the solubility of galena under the ambient condition. In a 6-day reaction period, the dissolution rate of galena increased with pH due to the oxidation of dissolved sulfide. Hence, formation of chloropyromorphite became apparent in the galena-apatite suspensions with increasing pH. The insignificant effect of mineral P/Pb molar ratio on the formation of chloropyromorphite implied that dissolution/oxidation of galena was the rate-limiting step. C1 Sandia Natl Labs, Dept Geochem, Albuquerque, NM 87185 USA. US EPA, Natl Risk Management Res Lab, Cincinnati, OH 45224 USA. RP Zhang, PC (reprint author), Sandia Natl Labs, Dept Geochem, MS 0750, Albuquerque, NM 87185 USA. NR 26 TC 68 Z9 75 U1 1 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD FEB 15 PY 1999 VL 33 IS 4 BP 618 EP 624 DI 10.1021/es980314a PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 166VN UT WOS:000078598600015 ER PT J AU Zhang, PC Ryan, JA AF Zhang, PC Ryan, JA TI Transformation of Pb(II) from cerrusite to chloropyromorphite in the presence of hydroxyapatite under varying conditions of pH SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID LEAD IMMOBILIZATION; CONTAMINATED SOILS; AQUEOUS-SOLUTIONS; STREET DUSTS; PB; BIOAVAILABILITY; PYROMORPHITE; PHOSPHATES; SPECIATION; SOLUBILITY AB The soluble Pb concentration and formation of chloro-pyromorphite [Pb-5(PO4)(3)Cl] were monitored during the reaction of cerrusite (PbCO3), a highly bioavailable soil Pb species, and hydroxyapatite [Ca-5(PO4)(3)OH] at various P/Pb molar ratios under constant and dynamic pH conditions. Under pH-constant systems at pH 4 and below, the dissolution rates of both cerrusite and apatite were rapid, and complete conversion of cerrusite to chloropyromorphite occurred within 60 min when the amount of phosphate added via apatite was stoichiometrically equal to that needed to transform all added Pb into chloropyromorphite. The concentration of soluble Pb depended upon the solubility of chloropyromorphite. The dissolution rates of apatite and cerrusite decreased with increasing pH, and the transformation was incomplete at pH 5 and above in the 60-min reaction period. The soluble Ph level, therefore, was determined by the solubility of cerrusite. In the pH-dynamic system, which simulated the gastrointestinal tract (GI tract), a complete transformation of Pb from cerrusite to chloropyromorphite was achieved due to the complete dissolution of apatite and cerrusite at the initial law pH. In both the constant and dynamic pH systems XRD analysis indicated that chloropyromorphite was the exclusive reaction product. The differences in transformation rate and the Pb solubility between the constant and dynamic pH systems indicate the significance of kinetics in controlling the bioavailability of Pb and the potential for the reaction to occur during ingestion. C1 Sandia Natl Labs, Dept Geochem, Albuquerque, NM 87185 USA. US EPA, Natl Risk Management Res Lab, Cincinnati, OH 45224 USA. RP Zhang, PC (reprint author), Sandia Natl Labs, Dept Geochem, MS 0750, Albuquerque, NM 87185 USA. NR 30 TC 100 Z9 107 U1 1 U2 17 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD FEB 15 PY 1999 VL 33 IS 4 BP 625 EP 630 DI 10.1021/es980268e PG 6 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 166VN UT WOS:000078598600016 ER PT J AU Crawford, J Ianzano, L Savino, M Whitmore, S Cleton-Jansen, AM Settasatian, C d'Apolito, M Seshadri, R Pronk, JC Auerbach, AD Verlander, PC Mathew, CG Tipping, AJ Doggett, NA Zelante, L Callen, DF Savoia, A AF Crawford, J Ianzano, L Savino, M Whitmore, S Cleton-Jansen, AM Settasatian, C d'Apolito, M Seshadri, R Pronk, JC Auerbach, AD Verlander, PC Mathew, CG Tipping, AJ Doggett, NA Zelante, L Callen, DF Savoia, A TI The PISSLRE gene: Structure, exon skipping, and exclusion as tumor suppressor in breast cancer SO GENOMICS LA English DT Article ID CHROMOSOME ARM 16Q; CYCLIN-DEPENDENT KINASES; CELL-CYCLE; PROSTATE ADENOCARCINOMA; MOLECULAR-CLONING; ALLELIC IMBALANCE; PROTEIN-KINASE; REGIONS; EXPRESSION; HETEROZYGOSITY AB In sporadic breast cancer, loss of heterozygosity (LOH) frequently occurs in three discrete regions of the long arm of chromosome 16q, the most telomeric of which is located at 16q24.3. Among the genes mapped to this region, PISSLRE is a plausible candidate tumor suppressor gene. It codes for a putative cyclin-dependent kinase that, as with other members of this family, is likely to be involved in regulating the cell cycle and therefore may have a role in oncogenesis. We characterized the genomic structure of PISSLRE and found that the splicing of this gene is complex. A variety of different transcripts were identified, including those due to cryptic splice sites, exon skipping, insertion of intronic sequences, and exon scrambling. The last phenomenon was observed in a rare PISSLRE transcript in which exons are joined at a nonconsensus splice site in an order different from that predicted by the genomic sequence. To screen the PISSLRE gene in breast tumors with ascertained LOH at 16q24-.3, we have analyzed each exon by single-strand conformational polymorphism. No variation was found in the coding sequence, leading us to conclude that another tumor suppressor must be targeted by LOH in sporadic breast cancer. (C) 1999 Academic Press. C1 IRCCS, Osped CSS, Serv Genet Med, I-71013 Foggia, Italy. Adelaide Womens & Childrens Hosp, Dept Cytogenet & Mol Genet, N Adelaide, SA 5006, Australia. Leiden Univ, Dept Pathol, Leiden, Netherlands. Free Univ Amsterdam, Dept Human Genet, Amsterdam, Netherlands. Rockefeller Univ, Lab Human Genet & Hematol, New York, NY 10021 USA. Guys Hosp, UMDS, Div Med & Mol Genet, London SE1 9RT, England. Univ Calif Los Alamos Natl Lab, Ctr Human Genome Studies, Los Alamos, NM 87545 USA. RP Savoia, A (reprint author), IRCCS, Osped CSS, Serv Genet Med, I-71013 Foggia, Italy. EM genetcss@fg.nettuno.it RI Callen, David/G-1975-2012; d'Apolito, Maria/G-5793-2012; Crawford, Joanna /F-9135-2013; Mathew, Christopher/G-3434-2015; Savoia, Anna/B-6463-2014; OI Crawford, Joanna /0000-0003-0786-6889; Mathew, Christopher/0000-0003-4178-1838; Savoia, Anna/0000-0002-2407-2696; Callen, David/0000-0002-6189-9991; Auerbach, Arleen/0000-0002-6911-8379 NR 30 TC 30 Z9 32 U1 0 U2 1 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0888-7543 J9 GENOMICS JI Genomics PD FEB 15 PY 1999 VL 56 IS 1 BP 90 EP 97 DI 10.1006/geno.1998.5676 PG 8 WC Biotechnology & Applied Microbiology; Genetics & Heredity SC Biotechnology & Applied Microbiology; Genetics & Heredity GA 171ET UT WOS:000078850100010 PM 10036189 ER PT J AU Lee, DF Paranthaman, M Mathis, JE Goyal, A Kroeger, DM Specht, ED Williams, RK List, FA Martin, PM Park, C Norton, DP Christen, DK AF Lee, DF Paranthaman, M Mathis, JE Goyal, A Kroeger, DM Specht, ED Williams, RK List, FA Martin, PM Park, C Norton, DP Christen, DK TI Alternative buffer architectures for high critical current density YBCO superconducting deposits on rolling assisted biaxially-textured substrates SO JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS LA English DT Letter DE superconductor; epitaxy; biaxial texture; textured substrate ID TAPES AB Although high critical current density (J(c)) YBCO can be deposited on rolling assisted biaxially-textured substrates (RABiTS) with the YSZ/CeO2/Ni architecture, improvement in uniformity is needed due to the presence of two-component YBCO epitaxy and cracking in the CeO2 buffer. We have determined that Yb2O3 is an excellent buffer material that provides a single-component YBCO epitaxy. In addition, crack-free epitaxial Y2O3 can be consistently deposited onto textured Ni substrates. High quality YBCO films have been deposited, and J(c) as high as 1.8 x 10(6) A/cm(2) at 77 K has been obtained on this Yb2O3/Y2O3/Ni: alternative RABiTS architecture. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Lee, DF (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. EM leedf@ornl.gov RI Yoon, Sejin/F-7637-2013; Paranthaman, Mariappan/N-3866-2015 OI Paranthaman, Mariappan/0000-0003-3009-8531 NR 7 TC 20 Z9 20 U1 0 U2 2 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 2 JI Jpn. J. Appl. Phys. Part 2 - Lett. PD FEB 15 PY 1999 VL 38 IS 2B BP L178 EP L180 DI 10.1143/JJAP.38.L178 PG 3 WC Physics, Applied SC Physics GA 182EX UT WOS:000079486800009 ER PT J AU Gopalan, V Mitchell, TE AF Gopalan, V Mitchell, TE TI In situ video observation of 180 degrees domain switching in LiTaO3 by electro-optic imaging microscopy SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID CRYSTALS; FIELD AB We report video observation of 180 degrees domain switching in congruent LiTaO3 under an external electric field by electro-optic imaging microscopy. The sideways wall velocity of independently growing 180 degrees domains in the Z plane of the crystal was measured to be 0.1-0.2 mm/s at a constant field of 21.2 kV/mm. The merging of independently growing domains results in a serrated domain front which displays an order of magnitude increase in the wall velocity to similar to 2.3 mm/s. We show that this is directly related to ledge formation upon domain merging where preferential nucleation takes place. These velocities are also an order of magnitude higher than those reported earlier for equivalent switching times that were measured by pulsed voltage application followed by ex situ optical observation. (C) 1999 American Institute of Physics. [S0021-8979(99)05004-5]. C1 Penn State Univ, Mat Res Lab, University Pk, PA 16802 USA. Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. RP Gopalan, V (reprint author), Penn State Univ, Mat Res Lab, University Pk, PA 16802 USA. NR 14 TC 74 Z9 74 U1 2 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD FEB 15 PY 1999 VL 85 IS 4 BP 2304 EP 2311 DI 10.1063/1.369542 PG 8 WC Physics, Applied SC Physics GA 163JV UT WOS:000078403000046 ER PT J AU Perlin, P Mattos, L Shapiro, NA Kruger, J Wong, WS Sands, T Cheung, NW Weber, ER AF Perlin, P Mattos, L Shapiro, NA Kruger, J Wong, WS Sands, T Cheung, NW Weber, ER TI Reduction of the energy gap pressure coefficient of GaN due to the constraining presence of the sapphire substrate SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID GALLIUM NITRIDE; HYDROSTATIC-PRESSURE; WURTZITE GAN; EPILAYER; PHOTOLUMINESCENCE; RAMAN; BAND AB We have performed a detailed investigation of the photoluminescence pressure dependence of heteroepitaxial GaN thin films on sapphire substrates. A comparison between as grown GaN on sapphire and free-standing GaN membranes, created using a laser assisted substrate liftoff process, revealed that the presence of the sapphire substrate leads to an energy gap pressure coefficient reduction of approximately 5%. This result agrees with the numerical simulations presented in this article. We established that the linear pressure coefficient of free-standing GaN is 41.4 +/- 0.2 meV/GPa, and that the deformation potential of the energy gap is -9.36 +/- 0.04 eV. Our results also suggest a new, lower value of the pressure derivative for the bulk modulus of GaN (B' = 3.5). (C) 1999 American Institute of Physics. [S0021-8979(99)06803- 6]. C1 Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Elect Engn & Comp Sci, Berkeley, CA 94720 USA. RP Perlin, P (reprint author), Lawrence Berkeley Lab, 1 Cyclotron Rd, Berkeley, CA 94720 USA. EM pperlin@ux8.lbl.gov RI Sands, Timothy/D-2133-2009 OI Sands, Timothy/0000-0001-9718-6515 NR 20 TC 70 Z9 82 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD FEB 15 PY 1999 VL 85 IS 4 BP 2385 EP 2389 DI 10.1063/1.369554 PG 5 WC Physics, Applied SC Physics GA 163JV UT WOS:000078403000058 ER PT J AU Vohra, YK Beaver, SL Akella, J Ruddle, CA Weir, ST AF Vohra, YK Beaver, SL Akella, J Ruddle, CA Weir, ST TI Ultrapressure equation of state of cerium metal to 208 GPa SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID GAMMA->ALPHA TRANSITION; PRESSURE; PHASES; CE AB We report static pressure compression of cerium metal to 208 GPa (volume compression V/V-0 = 0.37) in a diamond anvil cell at room temperature. Cerium is unique in the 4f elements because of proximity of the f shell to the Fermi energy and related phase transformations induced by pressure. The energy-dispersive x-ray diffraction studies were carried out on cerium metal to 208 GPa using a synchrotron x-ray source and an internal copper pressure standard. A collapsed body centered tetragonal phase is found to be stable to the highest pressure with axial ratio remarkably constant at 1.680 +/- 0.006 in the 90-208 GPa pressure range in excellent agreement with theory. Cerium is thus isostructural and isoelectronic with 5f -band metal thorium at ultrapressures. We present equation of state parameters, which describe the compression of cerium to ultrapressures. (C) 1999 American Institute of Physics. [S0021-8979(99)03404- 0]. C1 Univ Alabama Birmingham, Dept Phys, Birmingham, AL 35294 USA. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Univ Alabama Birmingham, Dept Phys, Birmingham, AL 35294 USA. EM vohra@phy.uab.edu RI Weir, Samuel/H-5046-2012 NR 17 TC 29 Z9 31 U1 1 U2 9 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD FEB 15 PY 1999 VL 85 IS 4 BP 2451 EP 2453 DI 10.1063/1.369566 PG 3 WC Physics, Applied SC Physics GA 163JV UT WOS:000078403000070 ER PT J AU Neyer, DW Heck, AJR Chandler, DW AF Neyer, DW Heck, AJR Chandler, DW TI Photodissociation of N2O: J-dependent anisotropy revealed in N-2 photofragment images SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ULTRAVIOLET-ABSORPTION SPECTRUM; STATE-RESOLVED STEREODYNAMICS; MULTIPHOTON IONIZATION; MOLECULAR-OXYGEN; NITROUS-OXIDE; DYNAMICS; PHOTOELECTRON; ALIGNMENT AB Photofragment imaging is used to measure the state-specific angular distributions of N-2 produced in the ultraviolet photodissociation of N2O. 2+1 REMPI (resonance enhanced multiphoton ionization) through the a"((1)Sigma(g)(+)) state is used to ionize individual rotational states of N-2(nu=0) between J=40 and J=90 produced when N2O is dissociated by light of approximately 203 nm. The anisotropy parameter, beta, used to characterize the angular distributions of the N-2 ion images, is greater than one for the lower rotational levels probed, and decreases to approximately zero for the highest rotational levels of N-2. The positive beta parameter indicates that the products arise primarily from a parallel transition to the 2 (1)A'((1)Delta) state in the parent molecule, and the decrease in beta with increasing J of N-2 is due to increased bending in the parent N2O during dissociation. The ion images also allow us to assign transitions in a spectroscopically perturbed region of the N-2 photofragment REMPI spectrum and to reveal the production of N-2 products in the first vibrationally excited state. (C) 1999 American Institute of Physics. [S0021-9606(99)00907-1]. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. RP Neyer, DW (reprint author), Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. RI Heck, Albert/D-7098-2011 OI Heck, Albert/0000-0002-2405-4404 NR 29 TC 56 Z9 57 U1 0 U2 10 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 15 PY 1999 VL 110 IS 7 BP 3411 EP 3417 DI 10.1063/1.478207 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 164DA UT WOS:000078446100017 ER PT J AU Kent, MS Majewski, J Smith, GS Lee, LT Satija, S AF Kent, MS Majewski, J Smith, GS Lee, LT Satija, S TI Tethered chains in poor solvent conditions: An experimental study involving Langmuir diblock copolymer monolayers SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID GRAFTED POLYMER LAYERS; MONTE-CARLO SIMULATION; NEUTRON REFLECTIVITY; PHASE-TRANSITION; COLLAPSED REGIME; BRUSH LAYERS; SURFACE; THETA; QUALITY; FIELD AB We have employed Langmuir monolayers of highly asymmetric polydimethylsiloxane-polystyrene (PDMS-PS) diblock copolymers on dioctyl phthalate (DOP) at temperatures ranging from 22 to -35 degrees C as a model system for tethered chains in poor solvent conditions. The thicknesses of the tethered PS layers extending into the DOP subphase, measured by neutron reflection, decrease with decreasing temperature (T) over this entire range. However, the variation with T becomes weak below -20 degrees C. At the lowest T, the layer thicknesses are 55%-75% of the values at the theta condition (T-theta = 22 degrees C). The contraction of the layer with decreasing T is determined as a function of surface density and molecular weight, and these data are compared to universal scaling forms. The PS segments are depleted from the near surface region over the entire T range, with the thickness of the depletion layer increasing slightly with decreasing T. The free energy of the surface layer is probed by surface tension measurements. With decreasing T, negative surface pressures are observed at low coverages for both PDMS-PS and PDMS monolayers, indicating metastability toward lateral phase separation. Evidence for a transition from a dispersed phase to a condensed phase with decreasing T was observed in the reflectivity for very low PDMS-PS coverage. At high coverage where the submerged blocks are strongly interacting at 22 degrees C, only a modest decrease in surface pressure is observed over the experimental range of T despite the strong contraction. This latter result is discussed in terms of the relative contributions of enthalpic and entropic effects to the surface pressure. (C) 1999 American Institute of Physics. [S0021-9606(99)51501-8]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. CENS, Lab Leon Brillouin, F-91191 Gif Sur Yvette, France. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Kent, MS (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. RI Lujan Center, LANL/G-4896-2012 NR 61 TC 11 Z9 11 U1 1 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 15 PY 1999 VL 110 IS 7 BP 3553 EP 3565 DI 10.1063/1.478223 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 164DA UT WOS:000078446100033 ER PT J AU Nilsson, SK Dooner, MS Weier, HU Frenkel, B Lian, JB Stein, GS Quesenberry, PJ AF Nilsson, SK Dooner, MS Weier, HU Frenkel, B Lian, JB Stein, GS Quesenberry, PJ TI Cells capable of bone production engraft from whole bone marrow transplants in nonablated mice SO JOURNAL OF EXPERIMENTAL MEDICINE LA English DT Article DE osteoprogenitors; osteoblasts; bone; bone marrow transplants; nonablated ID HEMATOPOIETIC STEM-CELLS; STROMAL CELLS; RADIATION CHIMERAS; DIFFUSION-CHAMBERS; PRECURSOR CELLS; ORIGIN; CARTILAGE AB Allogeneic and autologous marrow transplants are routinely used to correct a wide variety of diseases. In addition, autologous marrow transplants potentially provide opportune means of delivering genes in transfected, engrafting stem cells. However, relatively little is known about the mechanisms of engraftment in transplant recipients, especially in the nonablated setting and with regard to cells not of hemopoietic origin. In particular, this includes stromal cells and progenitors of the osteoblastic lineage. We have demonstrated for the first time that a whole bone marrow transplant contains cells that engraft and become competent osteoblasts capable of producing bone matrix. This was done at the individual cell level in situ, with significant numbers of donor cells being detected by fluorescence in situ hybridization in whole femoral sections. Engrafted cells were functionally active as osteoblasts producing bone before being encapsulated within the bone lacunae and terminally differentiating into osteocytes. Transplanted cells were also detected as flattened bone lining cells on the periosteal bone surface. C1 Univ Massachusetts, Med Ctr, Ctr Canc, Worcester, MA 01605 USA. Univ Massachusetts, Med Ctr, Dept Cell Biol, Worcester, MA 01605 USA. Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP Nilsson, SK (reprint author), Peter MacCallum Canc Inst, Sir Donald & Lady Trescowthick Res Labs, Locked Bag 1,Abeckett St, Melbourne, Vic 3000, Australia. RI Nilsson, Susie/C-5563-2015 OI Nilsson, Susie/0000-0002-7926-7335 FU NIDDK NIH HHS [DK 49650-02, DK 50222-01] NR 33 TC 109 Z9 121 U1 1 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 FEB 15 PY 1999 VL 189 IS 4 BP 729 EP 734 DI 10.1084/jem.189.4.729 PG 6 WC Immunology; Medicine, Research & Experimental SC Immunology; Research & Experimental Medicine GA 168NA UT WOS:000078698100015 PM 9989988 ER PT J AU Park, JJ Lee, JD AF Park, JJ Lee, JD TI Formation of subgrains in tungsten-rhenium-hafnium carbide alloys during creep SO JOURNAL OF MATERIALS SCIENCE LETTERS LA English DT Article C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Arizona State Univ, Dept Chem Biol & Mat Engn, Tempe, AZ 85287 USA. RP Park, JJ (reprint author), Univ Calif Los Alamos Natl Lab, MS E508 POB 1663, Los Alamos, NM 87545 USA. NR 8 TC 1 Z9 3 U1 0 U2 2 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 FEB 15 PY 1999 VL 18 IS 4 BP 273 EP 275 DI 10.1023/A:1006654416782 PG 3 WC Materials Science, Multidisciplinary SC Materials Science GA 196LN UT WOS:000080310000005 ER PT J AU Park, JJ AF Park, JJ TI Time-temperature parameters for creep-rupture data of W-4Re-0.3HfC SO JOURNAL OF MATERIALS SCIENCE LETTERS LA English DT Article C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Park, JJ (reprint author), Univ Calif Los Alamos Natl Lab, MS E508,POB 1663, Los Alamos, NM 87545 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 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 FEB 15 PY 1999 VL 18 IS 4 BP 277 EP 279 DI 10.1023/A:1006606500852 PG 3 WC Materials Science, Multidisciplinary SC Materials Science GA 196LN UT WOS:000080310000006 ER PT J AU Kennedy, BJ Howard, CJ Chakoumakos, BC AF Kennedy, BJ Howard, CJ Chakoumakos, BC TI Phase transitions in perovskite at elevated temperatures - a powder neutron diffraction study SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID CATIO3 PEROVSKITE; THERMAL-EXPANSION; HEAT-CAPACITY AB The structure of CaTiO3 has been studied at high temperatures by powder neutron diffraction methods. From inspection of the diffraction data two phase transitions are evident, with an intermediate tetragonal (I4/mcm) structure forming near 1500 K and a primitive cubic (Pm (3) over bar m) structure above 1580 K. Detailed Rietveld analyses of the data suggest there may also be a phase transition from the room temperature Pbnm structure to an orthorhombic Cmcm structure around 1380 K. A remarkable feature of the results is the regular variation in the out-of-phase octahedral tilt angle over the entire temperature range. C1 Univ Sydney, Sch Chem, Sydney, NSW 2006, Australia. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Kennedy, BJ (reprint author), Univ Sydney, Sch Chem, Sydney, NSW 2006, Australia. RI Howard, Christopher/B-5138-2009; Chakoumakos, Bryan/A-5601-2016; OI Chakoumakos, Bryan/0000-0002-7870-6543; Kennedy, Brendan/0000-0002-7187-4579 NR 28 TC 225 Z9 228 U1 4 U2 52 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 FEB 15 PY 1999 VL 11 IS 6 BP 1479 EP 1488 DI 10.1088/0953-8984/11/6/012 PG 10 WC Physics, Condensed Matter SC Physics GA 168LR UT WOS:000078694700012 ER PT J AU Burton, H AF Burton, H TI American women in science: 1950 to the present; A biographical dictionary. SO LIBRARY JOURNAL LA English DT Book Review C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Burton, H (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU BOWKER MAGAZINE GROUP CAHNERS MAGAZINE DIVISION PI NEW YORK PA 249 W 17TH ST, NEW YORK, NY 10011 USA SN 0363-0277 J9 LIBR J JI Libr. J. PD FEB 15 PY 1999 VL 124 IS 3 BP 140 EP 140 PG 1 WC Information Science & Library Science SC Information Science & Library Science GA 166CR UT WOS:000078559100029 ER PT J AU Csoto, A Langanke, K AF Csoto, A Langanke, K TI Large-space cluster model calculations for the He-3(He-3,2p)He-4 and H-3(H-3,2n)He-4 reactions SO NUCLEAR PHYSICS A LA English DT Article DE few-body systems; three-body dynamics; cluster model; nuclear astrophysics; solar neutrinos ID FUSION CROSS-SECTIONS; SOLAR NEUTRINOS; NUCLEUS HE-6; ELECTRON; RESONANCE; EXCITATION; BINDING; STATES AB The He-3(He-3, 2p)He-4 and H-3(H-3, 2n)He-4 reactions are studied in a microscopic cluster model. We search for resonances in the He-3+He-3 and He-4 + p + p channels using methods that treat the two- and three-body resonance asymptotics correctly. Our results show that the existence of a low-energy resonance or virtual slate, which could influence the Be-7 and B-8 solar neutrino fluxes, is rather unlikely. Our calculated He-3(He-3,2p)He-4 and H-3(H-3,2n)He-4 cross sections are in a good general agreement with the experimental data. (C) 1999 Elsevier Science B.V. C1 Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Aarhus Univ, Inst Phys & Astron, DK-8000 Aarhus, Denmark. Eotvos Lorand Univ, Dept Atom Phys, H-1117 Budapest, Hungary. RP Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 50 TC 10 Z9 10 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 EI 1873-1554 J9 NUCL PHYS A JI Nucl. Phys. A PD FEB 15 PY 1999 VL 646 IS 3 BP 387 EP 396 DI 10.1016/S0375-9474(98)00638-1 PG 10 WC Physics, Nuclear SC Physics GA 166JC UT WOS:000078571600005 ER PT J AU Siders, CW Siders, JLW Taylor, AJ Park, SG Melloch, MR Weiner, AM AF Siders, CW Siders, JLW Taylor, AJ Park, SG Melloch, MR Weiner, AM TI Generation and characterization of terahertz pulse trains from biased, large-aperture photoconductors SO OPTICS LETTERS LA English DT Article ID BAND THZ RADIATION AB The saturation properties of terahertz emission from biased, large-aperture photoconductors excited by trains of amplified femtosecond optical pulses are presented. A direct comparison is made of the multiple-pulse saturation properties of terahertz emission from semi-insulating GaAs and low-temperature-grown GaAs emitters with different carrier lifetimes. When the carrier lifetime is less than or comparable with the interpulse spacing, a significant enhancement of the narrow-band terahertz output is observed. The enhancement is not observed for emitters with long carrier lifetimes, consistent with the results of a previously derived saturation theory [Opt. Lett. 18, 1340 (1993)]. (C) 1999 Optical Society of America. OCIS codes: 320.7160, 320.7080, 320.7100, 320.7130. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. Purdue Univ, Sch Elect & Comp Engn, W Lafayette, IN 47907 USA. RP Siders, CW (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. NR 10 TC 38 Z9 40 U1 0 U2 5 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 FEB 15 PY 1999 VL 24 IS 4 BP 241 EP 243 DI 10.1364/OL.24.000241 PG 3 WC Optics SC Optics GA 168EZ UT WOS:000078679700019 PM 18071467 ER PT J AU Demos, SG Staggs, M Yan, M Radousky, HB De Yoreo, JJ AF Demos, SG Staggs, M Yan, M Radousky, HB De Yoreo, JJ TI Microscopic fluorescence imaging of bulk defect clusters in KH2PO4 crystals SO OPTICS LETTERS LA English DT Article ID POTASSIUM DIHYDROGEN PHOSPHATE; ELECTRONIC DEFECTS; ALKALI-HALIDES; AGGREGATION AB A microscopic fluorescence imaging system is used to detect optically active centers located inside a transparent dielectric crystal. Defect centers in the bulk of KH2PO4 crystals are imaged based on their near-infrared emission following photoexcitation. The spatial resolution of the system is 1 mu m in the image plane and 25 mu m in depth. The experimental results indicate the presence of a large number of optically active defect clusters in different KH2PO4 crystals, whereas the concentration of these clusters depends on the crystal sector and growth method. (C) 1999 Optical Society of America. OCIS codes: 160.4330, 180.2520, 300.2530, 300.6250. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Demos, SG (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94551 USA. NR 16 TC 15 Z9 18 U1 0 U2 1 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 FEB 15 PY 1999 VL 24 IS 4 BP 268 EP + DI 10.1364/OL.24.000268 PG 11 WC Optics SC Optics GA 168EZ UT WOS:000078679700028 PM 18071476 ER PT J AU Schmeltzer, D Bishop, AR AF Schmeltzer, D Bishop, AR TI Theoretical investigation of the phases of the organic insulator (TMTTF)(2)PF6 SO PHYSICAL REVIEW B LA English DT Article ID QUANTUM ANTIFERROMAGNETS; 2 DIMENSIONS; SUPERCONDUCTORS; TRANSITIONS; BEHAVIOR AB An explanation of some phases of the organic insulator (TMTTF)(2)PF6 as a function of temperature, magnetic field, and pressure is given. It is shown that the problem can be mapped onto the (2 + 1)-dimensional nonlinear sigma model. The physics is described in terms of the coupling constant of this model, which encodes the one-dimensional two-body interactions and phonon effects. A phase diagram is proposed, including a possible quantum critical fixed point. [S0163-1829(99)01007-3]. C1 Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. CUNY City Coll, Dept Phys, New York, NY 10031 USA. RP Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 19 TC 6 Z9 6 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1999 VL 59 IS 7 BP 4541 EP 4544 DI 10.1103/PhysRevB.59.4541 PG 4 WC Physics, Condensed Matter SC Physics GA 169YZ UT WOS:000078778800001 ER PT J AU McCormick, KL Woodside, MT Huang, M Wu, MS McEuen, PL Duruoz, C Harris, JS AF McCormick, KL Woodside, MT Huang, M Wu, MS McEuen, PL Duruoz, C Harris, JS TI Scanned potential microscopy of edge and bulk currents in the quantum Hall regime SO PHYSICAL REVIEW B LA English DT Article ID FORCE MICROSCOPY; DISTRIBUTIONS; CONDUCTORS; CHANNELS; SYSTEM AB Using an atomic force microscope as a local voltmeter, we measure the Hall voltage profile in a two-dimensional electron gas in the quantum Hall (QH) regime. We observe a linear profile in the bulk of the sample in the transition regions between QH plateaus and a distinctly nonlinear profile on the plateaus. In addition, localized voltage drops an observed at the sample edges in the transition regions. We interpret these results in terms of theories of edge and bulk current in the QH regime. [S0163-1829(99)02908-2]. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Stanford Univ, Dept Elect Engn, Stanford, CA 94309 USA. RP McCormick, KL (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NR 28 TC 92 Z9 93 U1 0 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1999 VL 59 IS 7 BP 4654 EP 4657 DI 10.1103/PhysRevB.59.4654 PG 4 WC Physics, Condensed Matter SC Physics GA 169YZ UT WOS:000078778800030 ER PT J AU Heske, C Treusch, R Himpsel, FJ Kakar, S Terminello, LJ Weyer, HJ Shirley, EL AF Heske, C Treusch, R Himpsel, FJ Kakar, S Terminello, LJ Weyer, HJ Shirley, EL TI Band widening in graphite SO PHYSICAL REVIEW B LA English DT Article ID PHOTOELECTRON ANGULAR-DISTRIBUTIONS; ANGLE-RESOLVED PHOTOEMISSION; SYNCHROTRON-RADIATION; METALS; STATES; EXCITATION; LIF(100); DIAMOND; ENERGY; NA AB The valence band width of graphite is determined with high accuracy by imaging the momentum distribution of photoelectrons for various binding energies. Compared to local-density-functional theory, the experimental band width (22.0 eV) is stretched by about 11%. Quasiparticle calculations, which properly describe electron interaction effects on the excited states of a solid, give a width of 21.8 eV, in agreement with the experiment within the experimental and theoretical relative uncertainty of about 1%. The results demonstrate the importance of including Anal-state and associated many-body effects into the theoretical description of the electronic structure of solids. [S0163-1829(99)11403-6]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source, Berkeley, CA 94720 USA. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Lawrence Livermore Natl Lab, Dept Appl Sci, Livermore, CA 94550 USA. Paul Scherrer Inst, Swiss Light Source, Villigen, Switzerland. Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Univ Wurzburg, Adv Light Source, Hubland, D-97074 Wurzburg, Germany. EM heske@physik.uni-wuerzburg.de RI Treusch, Rolf/C-3935-2015; OI Treusch, Rolf/0000-0001-8479-8862 NR 27 TC 57 Z9 57 U1 0 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1999 VL 59 IS 7 BP 4680 EP 4684 DI 10.1103/PhysRevB.59.4680 PG 5 WC Physics, Condensed Matter SC Physics GA 169YZ UT WOS:000078778800034 ER PT J AU Bickham, SR AF Bickham, SR TI Numerical calculation of relaxation rates in amorphous silicon SO PHYSICAL REVIEW B LA English DT Article ID COMPUTER-SIMULATION; MOLECULAR-DYNAMICS; ELASTIC PROPERTIES; MODEL; SI; TEMPERATURE; PHONONS; STATES; DECAY; GE AB Relaxation rates for strong and weal; perturbations of the vibrational spectrum in amorphous silicon have been calculated using molecular dynamics simulations. A strong perturbation produced by creating a nonequilibrium normal mode distribution was found to relax on a 100 ps time scale. A weak perturbation generated by exciting a small number of modes in an equilibrated system yielded vibrational lifetimes on the order of 10 ps. Thermalization following the insertion of a heat pulse into the center of the simulation supercell also occurred on a 10 ps time scale. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Bickham, SR (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 26 TC 7 Z9 7 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1999 VL 59 IS 7 BP 4894 EP 4897 DI 10.1103/PhysRevB.59.4894 PG 4 WC Physics, Condensed Matter SC Physics GA 169YZ UT WOS:000078778800061 ER PT J AU Jeong, S Bokor, J AF Jeong, S Bokor, J TI Ultrafast carrier dynamics near the Si(100)2x1 surface SO PHYSICAL REVIEW B LA English DT Article ID ANGLE-RESOLVED PHOTOEMISSION; ELECTRON DYNAMICS; BAND-STRUCTURE; SI; SPECTROSCOPY; SILICON; SI(001); STATES; PULSES AB We present a time-resolved photoemission study of carrier dynamics near the Si(100)2x1 surface. It is found that the dominant contribution to the photoemission process originates from defect states on the Si(100)2x1 surface. Enhanced optical absorption is observed for these defect slates and carrier exchange between these states and the bulk is observed. The electron density near the surface and the shape of the electron energy distribution are found to change on a very fast time scale. A simple theoretical model is established to extract transport parameters from the observed electron energy distribution. [S0163-1829(99)07107-6]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Elect Engn & Comp Sci, Berkeley, CA 94720 USA. RP Jeong, S (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Xray Opt, 1 Cyclotron Rd, Berkeley, CA 94720 USA. RI Bokor, Jeffrey/A-2683-2011 NR 25 TC 21 Z9 22 U1 0 U2 9 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 FEB 15 PY 1999 VL 59 IS 7 BP 4943 EP 4951 DI 10.1103/PhysRevB.59.4943 PG 9 WC Physics, Condensed Matter SC Physics GA 169YZ UT WOS:000078778800067 ER PT J AU Yeh, AT Cerullo, G Banin, U Mews, A Alivisatos, AP Shank, CV AF Yeh, AT Cerullo, G Banin, U Mews, A Alivisatos, AP Shank, CV TI Dynamics of exciton localization in CdS/HgS quantum-dot quantum wells SO PHYSICAL REVIEW B LA English DT Article ID STIMULATED RAMAN-SCATTERING; RESONANCE RAMAN; PUMP-PROBE; NANOCRYSTALS; SPECTROSCOPY; PHOTOPHYSICS; CONFINEMENT; RELAXATION; COHERENT; POLYMERS AB Localization of carrier wave functions to the quantum-well portion of the CdS/HgS quantum-dot quantum well (QDQW) is investigated. Nanosecond hole-burning (HB) spectra measure the photoinduced exciton coupling to a 250-cm(-1) HgS phonon mode indicative of localization. Femtosecond pump-probe spectroscopy of these QDQW, however, show the photoinduced exciton couples to coherent 300-cm(-1) CdS longitudinal optical-phonon modes, which is indicative of delocalization throughout the QDQW. Femtosecond HE and three pulse pump-dump experiments reveal these results are dependent on the time scale of the experiment. These experiments indicate that the initially photoexcited electron and hole wave functions are weakly confined to the HSS monolayer. Only after long times (similar to 400 fs) will the exciton localize to the HgS well. These results indicate that the primary optical interaction excites electrons from a delocalized QDQW ground state and nor from a localized HgS well state. [S0163-1829(99)10307-2]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Yeh, AT (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Cerullo, Giulio/F-6534-2011; Alivisatos , Paul /N-8863-2015; OI Alivisatos , Paul /0000-0001-6895-9048; Cerullo, Giulio/0000-0002-9534-2702 NR 35 TC 28 Z9 29 U1 1 U2 8 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1999 VL 59 IS 7 BP 4973 EP 4979 DI 10.1103/PhysRevB.59.4973 PG 7 WC Physics, Condensed Matter SC Physics GA 169YZ UT WOS:000078778800071 ER PT J AU Kwok, SH Yu, PY Tung, CH Zhang, YH Li, MF Peng, CS Zhou, JM AF Kwok, SH Yu, PY Tung, CH Zhang, YH Li, MF Peng, CS Zhou, JM TI Confinement and electron-phonon interactions of the E-1 exciton in self-organized Ge quantum dots SO PHYSICAL REVIEW B LA English DT Article ID STRAINED-LAYER SUPERLATTICES; SI/GE SUPERLATTICES; FILMS AB We have utilized resonant Raman scattering to investigate the phonon modes of self-organized Cc quantum dots grown by molecular-beam epitaxy. Both Ge-Ge and Si-Ge phonon modes are found to exhibit strong enhancements at the E-1 exciton. The strain in the quantum dots deduced from the phonon energies is consistent with the results of high-resolution transmission electron microscopy. An upper bound on the confinement energy of the E-1 exciton in quantum dots was deduced. The enhancement strength in the Si-Ge phonon indicates strong interaction between this mode and the E-1 exciton of the Ge dots. [S0163-1829(99)12403-2]. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Inst Microelect, Dept Failure Anal & Reliabil, Singapore 117685, Singapore. Natl Univ Singapore, Dept Elect Engn, Singapore 119260, Singapore. Chinese Acad Sci, Inst Phys, Beijing 100080, Peoples R China. Chinese Acad Sci, Ctr Condensed Matter Phys, Beijing 100080, Peoples R China. RP Kwok, SH (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NR 21 TC 63 Z9 65 U1 0 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1999 VL 59 IS 7 BP 4980 EP 4984 DI 10.1103/PhysRevB.59.4980 PG 5 WC Physics, Condensed Matter SC Physics GA 169YZ UT WOS:000078778800072 ER PT J AU Valla, T Johnson, PD Dhesi, SS Smith, KE Doppalapudi, D Moustakas, TD Shirley, EL AF Valla, T Johnson, PD Dhesi, SS Smith, KE Doppalapudi, D Moustakas, TD Shirley, EL TI Unoccupied band structure of wurtzite GaN(0001) SO PHYSICAL REVIEW B LA English DT Article ID ELECTRONIC-STRUCTURE; GAN; ABSORPTION; SURFACE; GROWTH; FILMS AB We report an inverse photoemission study of the unoccupied states of thin-film n-type wurtzite GaN. For incident electron energies below 30 eV, free-electron bands do not provide a good description of the initial state. However, using a calculated quasiparticle band structure for the initial state, we can obtain good agree ment between our measurements and the calculated low-lying conduction bands. No evidence of unoccupied surface states is observed in the probed part of the Brillouin zone, confirming earlier angle resolved photoemission studies, which identified the surface states on GaN(0001) as occupied dangling bond states, resonant with the valence band. [S0163-1829(99)09007-4]. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Boston Univ, Dept Phys, Boston, MA 02215 USA. Boston Univ, Dept Elect & Comp Engn, Boston, MA 02215 USA. NIST, PHY B208, Gaithersburg, MD 20899 USA. RP Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RI Moustakas, Theodore/D-9249-2016 OI Moustakas, Theodore/0000-0001-8556-884X NR 15 TC 17 Z9 17 U1 0 U2 11 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1999 VL 59 IS 7 BP 5003 EP 5007 DI 10.1103/PhysRevB.59.5003 PG 5 WC Physics, Condensed Matter SC Physics GA 169YZ UT WOS:000078778800076 ER PT J AU Buldum, A Ciraci, S Fong, CY Nelson, JS AF Buldum, A Ciraci, S Fong, CY Nelson, JS TI Interpretation of long-range interatomic force SO PHYSICAL REVIEW B LA English DT Article ID SCANNING-TUNNELING MICROSCOPY; METALLIC CONTACTS; TIP; SURFACES; DYNAMICS; ADHESION; FLAT; CONDUCTANCE; MECHANISMS; SILICON AB Recent direct mechanical measurements of atomic force microscopy showed that the force between the silicon tip and the silicon sample is long range in the attractive region and its magnitude at maximum is relatively smaller. These features disagree with previous theoretical predictions based on the ab initio calculations. We investigated the nature of forces between a silicon tip and the silicon (111)-(2X1) surface by performing first-principles pseudopotential and classical molecular dynamics calculations and by calculating the van der Waals interaction. The first two methods give forces that are short range in nature. Fair agreement between the experiment and theory is obtained when the van der Waals interaction is included. The effect of the tip induced deformation is analyzed. [S0163-1829(99)04504-X]. C1 Bilkent Univ, Dept Phys, TR-06533 Bilkent, Ankara, Turkey. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Sandia Natl Labs, Semicond Phys Div, Albuquerque, NM 87185 USA. RP Buldum, A (reprint author), Bilkent Univ, Dept Phys, TR-06533 Bilkent, Ankara, Turkey. NR 45 TC 11 Z9 11 U1 0 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1999 VL 59 IS 7 BP 5120 EP 5125 DI 10.1103/PhysRevB.59.5120 PG 6 WC Physics, Condensed Matter SC Physics GA 169YZ UT WOS:000078778800092 ER PT J AU MacLaren, JM Zhang, XG Butler, WH Wand, XD AF MacLaren, JM Zhang, XG Butler, WH Wand, XD TI Layer KKR approach to Bloch-wave transmission and reflection: Application to spin-dependent tunneling SO PHYSICAL REVIEW B LA English DT Article ID ELECTRONIC-STRUCTURE; MAGNETORESISTANCE; TEMPERATURE; JUNCTIONS AB Bloch waves may be reflected and transmitted by planar interfaces. In this paper, we show how the reflection and transmission amplitudes for Bloch waves can be calculated within the layer Korringa-Kohn-Rostoker formalism. The calculated transmission probability is used to calculate the spin-dependent tunneling conductance for magnetic tunnel junctions formed from ZnSe semiconducting layers sandwiched between two ferromagnetic Fe layers. [SO163-1829(99)01308-9]. C1 Tulane Univ, Dept Phys, New Orleans, LA 70118 USA. Oak Ridge Natl Lab, Computat Phys & Engn Div, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP MacLaren, JM (reprint author), Tulane Univ, Dept Phys, New Orleans, LA 70118 USA. NR 29 TC 204 Z9 205 U1 2 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 FEB 15 PY 1999 VL 59 IS 8 BP 5470 EP 5478 DI 10.1103/PhysRevB.59.5470 PG 9 WC Physics, Condensed Matter SC Physics GA 173AZ UT WOS:000078959900032 ER PT J AU Branz, HM AF Branz, HM TI Hydrogen collision model: Quantitative description of metastability in amorphous silicon SO PHYSICAL REVIEW B LA English DT Article ID A-SI-H; LIGHT-INDUCED DEGRADATION; OXIDE-SEMICONDUCTOR TRANSISTORS; HOT-ELECTRON DEGRADATION; SOLAR-CELLS; ELEVATED-TEMPERATURES; CONDUCTIVITY CHANGES; DEFECT CREATION; DIFFUSION; KINETICS AB The hydrogen collision model of light-induced metastability in hydrogenated amorphous silicon is described in detail. Recombination of photogenerated carriers excites mobile H from Si-H bonds, leaving threefold-coordinated Si dangling-bond defects. When two mobile H atoms collide and associate in a metastable two-H complex, the-two dangling bonds from which H was emitted also become metastable. The proposed microscopic mechanism is consistent with electron-spin-resonance experiments. Comprehensive rate equations for the dangling-bond and mobile-H densities are presented; these equations include light-induced creation and annealing, Important regimes are solved analytically and numerically. The model provides explanations for both the t(1/3) time dependence: of the rise of defect density during continuous illumination and the t(1/2) time-dependence during intense laser-pulse illumination. Other consequences and predictions of the H collision model are described. [S0165-1829(99)04308-8]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Branz, HM (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. NR 71 TC 188 Z9 189 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 FEB 15 PY 1999 VL 59 IS 8 BP 5498 EP 5512 DI 10.1103/PhysRevB.59.5498 PG 15 WC Physics, Condensed Matter SC Physics GA 173AZ UT WOS:000078959900035 ER PT J AU Branz, HM Asher, S Gleskova, H Wagner, S AF Branz, HM Asher, S Gleskova, H Wagner, S TI Light-induced D diffusion measurements in hydrogenated amorphous silicon: Testing H metastability models SO PHYSICAL REVIEW B LA English DT Article ID A-SI-H; CONDUCTIVITY CHANGES; TRACER DIFFUSION; DEFECTS; DEUTERIUM; ILLUMINATION; DEGRADATION; MECHANISM AB We measure light-induced D tracer diffusion in hydrogenated amorphous silicon samples under conditions at which thermal diffusion is negligible. Under high-intensity (9W cm(-2)), red-light soaking at 135 degrees C, the D diffusion coefficient is D-D = 1.3 X 10(-18) cm(2) s(-1) and the rate of D;emission from Si-D to transport is 3.5 X 10(-5) s(-1). We also find an upper bound of D-D = 3 X 10(-20) cm(2) s(-1), the light-induced diffusion coefficient at 65 degrees C. Previous experiments had revealed only "light-enhanced" diffusion between from 200 to 300 degrees C, a regime in which thermal diffusion is also significant. Our 135 degrees C result extends the range of the 0.9-eV activation energy for this diffusion; our 65 degrees C upper bound is consistent with the extrapolation of the higher temperature data. We also measure metastable defect creation at 65 and 135 degrees C to test models of light-induced metastability that involve emission of H from Si-H bonds to an H transport level. This class of models can be limited, but not excluded, by our data. The H emission parameter of the H collision model of metastability is also estimated. [S0163-1829(99)09407-2]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. Princeton Univ, Dept Elect Engn, Princeton, NJ 08544 USA. RP Branz, HM (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Gleskova, Helena /J-1597-2015 OI Gleskova, Helena /0000-0001-7195-9639 NR 30 TC 28 Z9 28 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 FEB 15 PY 1999 VL 59 IS 8 BP 5513 EP 5520 DI 10.1103/PhysRevB.59.5513 PG 8 WC Physics, Condensed Matter SC Physics GA 173AZ UT WOS:000078959900036 ER PT J AU Fu, HX Wang, LW Zunger, A AF Fu, HX Wang, LW Zunger, A TI Excitonic exchange splitting in bulk semiconductors SO PHYSICAL REVIEW B LA English DT Article ID INP QUANTUM DOTS; CYCLOTRON-RESONANCE; MAGNETIC-FIELDS; BAND-GAPS; CRYSTALS; ENERGY; INSULATORS; STATES; DARK AB We present an approach to calculate the excitonic fine-structure splittings due to electron-hole short-range exchange interactions using the local-density approximation pseudopotential method, and apply it to bulk semiconductors CdSe, InP, GaAs, and InAs. Comparing with previous theoretical results, the current calculated splittings agree well with experiments. Furthermore, we provide an approximate relationship between the short-range exchange splitting and the exciton Bohr radius, which can be used to estimate the exchange splitting for other materials. The current calculation indicates Chat a commonly used formula for exchange splitting in quantum dot is not valid. Finally, we find a very large pressure dependence of the exchange splitting: a factor of 4.5 increase as the lattice constant changes by 3.5%. This increase is mainly due to the decrease of the Bohr radius via the char;ge of electron effective mass. [S0163-1829(99)02407-8]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Fu, HX (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Zunger, Alex/A-6733-2013 NR 55 TC 61 Z9 61 U1 3 U2 21 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1999 VL 59 IS 8 BP 5568 EP 5574 DI 10.1103/PhysRevB.59.5568 PG 7 WC Physics, Condensed Matter SC Physics GA 173AZ UT WOS:000078959900042 ER PT J AU Usukura, J Suzuki, Y Varga, K AF Usukura, J Suzuki, Y Varga, K TI Stability of two- and three-dimensional excitonic complexes SO PHYSICAL REVIEW B LA English DT Article ID STOCHASTIC VARIATIONAL METHOD; CORRELATED GAUSSIAN-BASIS; FEW-BODY PROBLEMS; BINDING-ENERGY; QUANTUM WELLS; GROUND-STATE; BIEXCITONS; MICROCRYSTALS; MOLECULE; ELECTRON AB The binding energies and other properties of the excitonic complexes (bound systems of electrons and holes) in two and three dimensions (2D and 3D) are calculated by a precise variational method. The mass ratios for the limit of the stability of X-3(+)(eehhh) are determined in both 2D and 3D cases. Two excited states of the biexciton are found to remain bound for any mass ratio. [S0163-1829(99)01608-2]. C1 Niigata Univ, Grad Sch Sci & Technol, Niigata 9502181, Japan. Niigata Univ, Dept Phys, Niigata 9502181, Japan. RIKEN, Inst Phys & Chem Res, Wako, Saitama 3510198, Japan. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Hungarian Acad Sci, Inst Nucl Res, ATOMKI, H-4001 Debrecen, Hungary. RP Usukura, J (reprint author), Niigata Univ, Grad Sch Sci & Technol, Niigata 9502181, Japan. RI Varga, Kalman/A-7102-2013 NR 29 TC 56 Z9 56 U1 0 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1999 VL 59 IS 8 BP 5652 EP 5661 DI 10.1103/PhysRevB.59.5652 PG 10 WC Physics, Condensed Matter SC Physics GA 173AZ UT WOS:000078959900054 ER PT J AU Wang, LW Kim, JN Zunger, A AF Wang, LW Kim, JN Zunger, A TI Electronic structures of [110]-faceted self-assembled pyramidal InAs/GaAs quantum dots SO PHYSICAL REVIEW B LA English DT Article ID ISLANDS; GAAS; PSEUDOPOTENTIALS; EXCITONS; ENERGIES; STATES; GROWTH; BOXES AB We calculate the electronic structures of pyramidal quantum dots with supercells containing 250000 atoms. using spin-orbit-coupled, nonlocal, empirical pseudopotentials. We compare the results with previous theoretical calculations, Our calculation circumvents the approximations underlying the conventional effective-mass approach: we describe the potential, the strain and the wave functions using atomistic rather than continuum models. The potential is given by a superposition of screened atomic pseudopotentials, the strain is obtained from minimizing the atomistic strain energy, and the wave function is expanded using a plane-wave basis set. We find the following. (1) The conduction bands. are formed essentially from single envelope functions, so they can be classified according td the: nodal structure as s, p, and d. However, due to strong multiband coupling, most notably light hole with heavy hole, the valence states cannot be classified in the language of single-band envelope functions. In fact, the hole states have no nodal planes. (2) There is a strong anisotropy in the polarization of the lowest valence state to conduction state optical transition. This is in contrast to the eight band k.p model, which finds essentially zero anisotropy. (3) There are at least four bound electron states for a 113-Angstrom-based quantum dot, This number of bound states is larger than that found in eight band kp calculations. (4) Since our atomistic description retains the correct C-2v symmetry of a square-based pyramid made of zinc-blende solids, we find that the otherwise degenerate p states are split by about 25 meV. This splitting is underestimated in the eight-band k.p calculation. [50163-1829(99)00608-6]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Wang, LW (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Zunger, Alex/A-6733-2013 NR 54 TC 222 Z9 223 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 FEB 15 PY 1999 VL 59 IS 8 BP 5678 EP 5687 DI 10.1103/PhysRevB.59.5678 PG 10 WC Physics, Condensed Matter SC Physics GA 173AZ UT WOS:000078959900056 ER PT J AU Len, PM Denlinger, JD Rotenberg, E Kevan, SD Tonner, BP Chen, Y Van Hove, MA Fadley, CS AF Len, PM Denlinger, JD Rotenberg, E Kevan, SD Tonner, BP Chen, Y Van Hove, MA Fadley, CS TI Holographic atomic images from surface and bulk W(110) photoelectron diffraction data SO PHYSICAL REVIEW B LA English DT Article ID ELECTRON-EMISSION HOLOGRAPHY; X-RAY HOLOGRAPHY; LOW-ENERGY-ELECTRON; AUGER-ELECTRON; MULTIPLE-SCATTERING; FLUORESCENCE HOLOGRAPHY; SOURCE-WAVE; RECONSTRUCTION; PATTERNS; CRYSTALLOGRAPHY AB Photoelectron diffraction data can, in principle, be regarded as enabling the experimental recording of electron diffraction phases (relative to a direct reference wave), as well as intensities, thus also permitting the holographic reconstruction of atomic positions. Such holographic photoelectron diffraction patterns have been measured for surface and bulk core-level-shifted W 4f photoemission from W(110), yielding a data set of unprecedented size and quality. To test the role of experimental uncertainties and of multiple-scattering effects, we have also performed corresponding theoretical calculations at the single- and multiple-scattering levels. The surface and bulk holograms so obtained have been analyzed so as to provide the first parallel comparison of the three-dimensional atomic images that can be directly obtained via the five principal reconstruction algorithms proposed to date. The advantages and disadvantages of each of these methods are discussed. The prospects and limitations of atomic photoelectron holography as an ab initio technique for determining local-surface structures are also explored. [S0163-1829(99)08207-7]. C1 Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Wisconsin, Dept Phys, Milwaukee, WI 53211 USA. Univ Oregon, Dept Phys, Eugene, OR 97403 USA. Univ Wisconsin, Dept Phys, Milwaukee, WI 53211 USA. RP Len, PM (reprint author), Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. RI Rotenberg, Eli/B-3700-2009; Van Hove, Michel/A-9862-2008; Kevan, Stephen/F-6415-2010 OI Rotenberg, Eli/0000-0002-3979-8844; Van Hove, Michel/0000-0002-8898-6921; Kevan, Stephen/0000-0002-4621-9142 NR 65 TC 29 Z9 30 U1 0 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1999 VL 59 IS 8 BP 5857 EP 5870 DI 10.1103/PhysRevB.59.5857 PG 14 WC Physics, Condensed Matter SC Physics GA 173AZ UT WOS:000078959900076 ER PT J AU Feibelman, PJ Stumpf, R AF Feibelman, PJ Stumpf, R TI Adsorption-induced lattice relaxation and diffusion by concerted substitution SO PHYSICAL REVIEW B LA English DT Article ID TOTAL-ENERGY CALCULATIONS; SURFACE SELF-DIFFUSION; WAVE BASIS-SET; MOLECULAR-DYNAMICS; IR(001) SURFACE; METALS; RECONSTRUCTION; TRANSITION; SEMICONDUCTORS; MECHANISM AB Ab initio calculations show that the barrier to surface self-diffusion by concerted substitution (CS) is lower on those transition-metal (100) surfaces where the substrate relaxation around an adatom, and the corresponding energy gain, are greater. Stress calculations contradict the notion that lower barrier CS corresponds to larger tensile stress reduction along the CS diffusion path. [S0163-1829 (99)07007-1]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 30 TC 28 Z9 29 U1 0 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1999 VL 59 IS 8 BP 5892 EP 5897 DI 10.1103/PhysRevB.59.5892 PG 6 WC Physics, Condensed Matter SC Physics GA 173AZ UT WOS:000078959900080 ER PT J AU Di Ventra, M Pantelides, ST AF Di Ventra, M Pantelides, ST TI Scanning-tunneling-microscopy images: A fully ab initio approach SO PHYSICAL REVIEW B LA English DT Article ID ATOMIC-RESOLUTION; METAL-SURFACES; POINT-CONTACT; CONDUCTANCE; TRANSPORT AB A fully ab initio approach to scanning-tunneling-microscope (STM) images is presented, treating the sample and the tip as a single system. The approach combines density functional theory with the Kubo-Greenwood formalism for the conductivity. The STM images are calculated by taking into account atomic relaxations that occur on both the surface and the tip due to their mutual interactions. illustrative examples will be presented for the ease of a clean A1(110) surface and the same surface with a vacancy, showing that buckling relaxations occur that smooth the STM images, reducing the observable corrugation pf the surface. C1 Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. RI Di Ventra, Massimiliano/E-1667-2011 OI Di Ventra, Massimiliano/0000-0001-9416-189X NR 33 TC 19 Z9 19 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1999 VL 59 IS 8 BP R5320 EP R5323 DI 10.1103/PhysRevB.59.R5320 PG 4 WC Physics, Condensed Matter SC Physics GA 173AZ UT WOS:000078959900015 ER PT J AU Malek, J Flach, S Kladko, K AF Malek, J Flach, S Kladko, K TI Incremental expansions for the ground-state energy of the two-dimensional Hubbard model SO PHYSICAL REVIEW B LA English DT Article ID HEISENBERG-ANTIFERROMAGNET AB A generalization of Faddeev'S approach of the three-body problem to the many-body problem leads to the method of increments. This method was recently applied to account for the ground-state properties of Hubbard-Peierls chains [J. Malek, K. Kladko, and S. Flach, JETP Lett. 67, 1052 (1998)]. Here we generalize this approach to two-dimensional square lattices and explicitly treat the incremental expansion up to third order. Comparing our numerical results with various other approaches (Monte Carlo, cumulant approaches) we show that incremental expansions are very efficient because good accuracy with these approaches is achieved treating lattice segments composed of eight sites only. C1 Max Planck Inst Phys Complex Syst, D-01187 Dresden, Germany. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. RP Malek, J (reprint author), Max Planck Inst Phys Complex Syst, Noethnitzer Str 38, D-01187 Dresden, Germany. RI Flach, Sergej/J-7047-2013; Malek, Jiri/G-7223-2014 NR 10 TC 2 Z9 2 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1999 VL 59 IS 8 BP R5273 EP R5276 DI 10.1103/PhysRevB.59.R5273 PG 4 WC Physics, Condensed Matter SC Physics GA 173AZ UT WOS:000078959900003 ER PT J AU Pohl, K Plummer, EW AF Pohl, K Plummer, EW TI Structure of the H-induced vacancy reconstruction of the (0001) surface of beryllium. SO PHYSICAL REVIEW B LA English DT Article ID HYDROGEN; LEED; DIFFRACTION; NI(110) AB A unique chemisorption structure has been determined for the (root 3 x root 3)R30 degrees H-Be(0001) phase formed at a saturation coverage of 1 ML and T less than or equal to 270 K. The analysis of low-energy-electron diffraction data shows that 1/3 of the Be top layer atoms are removed to form a honeycomb structure of Be vacancies. Each vacancy is decorated by three H adatoms bonded in tilted bridge sites with a H-Be bond length and angle of 1.53 Angstrom (+/- 0.2) and 42 degrees(+/- 10), respectively. C1 Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Pohl, K (reprint author), Sandia Natl Labs, Livermore, CA 94550 USA. NR 24 TC 2 Z9 2 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1999 VL 59 IS 8 BP R5324 EP R5327 DI 10.1103/PhysRevB.59.R5324 PG 4 WC Physics, Condensed Matter SC Physics GA 173AZ UT WOS:000078959900016 ER PT J AU Hochberg, D Molina-Paris, C Visser, M AF Hochberg, D Molina-Paris, C Visser, M TI Tolman wormholes violate the strong energy condition SO PHYSICAL REVIEW D LA English DT Article ID GRAVITATIONAL VACUUM POLARIZATION; GENERAL-RELATIVITY; DYNAMIC WORMHOLES; GALAXY FORMATION; SINGULARITIES; INFLATION; COSMOLOGY; SPACETIME; AVOIDANCE; EPOCH AB For an arbitrary Tolman wormhole. unconstrained by symmetry, we shall define the bounce in terms of a 3-dimensional edgeless achronal spacelike hypersurface of minimal volume (zero trace for the extrinsic curvature plus a "flare-out" condition). This enables us to severely constrain the geometry of spacetime at and near the bounce and to derive general theorems regarding violations of the energy conditions-theorems that do not involve geodesic averaging but nevertheless apply to situations much more general than the highly symmetric FRW-based subclass of Tolman wormholes. [For example, even under the mildest of hypotheses, the strong energy condition (SEC) must be violated.] Alternatively, one can dispense with the minimal volume condition and define a generic bounce entirely in terms of the motion of test particles (future-pointing timelike geodesics), by looking at the expansion of their timelike geodesic congruences. One re-confirms that the SEC must be violated at or near the bounce. In contrast, it is easy to arrange for all the other standard energy conditions to be satisfied. [S0556-2821(99)06802-2]. C1 Lab Astrofis Espacial & Fis Fundamental, Madrid 28080, Spain. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Washington Univ, Dept Phys, St Louis, MO 63130 USA. RP Hochberg, D (reprint author), Lab Astrofis Espacial & Fis Fundamental, Apartado 50727, Madrid 28080, Spain. EM hochberg@laeff.esa.es; carmen@t6-serv.lanl.gov; visser@kiwi.wustl.edu NR 39 TC 18 Z9 18 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD FEB 15 PY 1999 VL 59 IS 4 AR 044011 DI 10.1103/PhysRevD.59.044011 PG 8 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 189ZY UT WOS:000079938100034 ER PT J AU Alexa, LC Anderson, BD Aniol, KA Arundell, K Auerbach, L Baker, FT Berthot, J Bertin, PY Bertozzi, W Bimbot, L Boeglin, WU Brash, EJ Breton, V Breuer, H Burtin, E Calarco, JR Cardman, LS Cavata, C Chang, CC Chen, JP Chudakov, E Cisbani, E Dale, DS Degrande, N De Leo, R Deur, A d'Hose, N Diederich, B Domingo, JJ Epstein, MB Ewell, LA Finn, JM Fissum, KG Fonvieille, H Frois, B Frullani, S Gao, H Gao, J Garibaldi, F Gasparian, A Gilad, S Gilman, R Glamazdin, A Glashausser, C Gomez, J Gorbenko, V Hansen, JO Holmes, R Holtrop, M Howell, C Huber, GM Hyde-Wright, C Iodice, M de Jager, CW Jaminion, S Jardillier, J Jones, MK Jutier, C Kahl, W Kato, S Katramatou, AT Kelly, JJ Kerhoas, S Ketikyan, A Khayat, M Kino, K Kramer, LH Kumar, KS Kumbartzki, G Kuss, M Lavessiere, G Leone, A LeRose, JJ Liang, M Lindgren, RA Liyanage, N Lolos, GJ Lourie, RW Madey, R Maeda, K Malov, S Manley, DM Margaziotis, DJ Markowitz, P Marroncle, J Martino, J Martoff, CJ McCormick, K McIntyre, J van der Meer, RLJ Mehrabyan, S Meziani, ZE Michaels, R Miller, GW Mougey, JY Nanda, SK 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 Rowntree, D Rutledge, G Rutt, PM Saha, A Saito, T Sarty, AJ Serdarevic, A Smith, T Soldi, K Sorokin, P Souder, PA Suleiman, R Templon, JA Terasawa, T Todor, L Tsubota, H Ueno, H Ulmer, PE Urciuoli, GM Van Hoorebeke, L Vernin, P Vlahovic, B Voskanyan, H Watson, JW Weinstein, LB Wijesooriya, K Wilson, R Wojtsekhowski, BB Zainea, DG Zhang, WM Zhao, J Zhou, ZL AF Alexa, LC Anderson, BD Aniol, KA Arundell, K Auerbach, L Baker, FT Berthot, J Bertin, PY Bertozzi, W Bimbot, L Boeglin, WU Brash, EJ Breton, V Breuer, H Burtin, E Calarco, JR Cardman, LS Cavata, C Chang, CC Chen, JP Chudakov, E Cisbani, E Dale, DS Degrande, N De Leo, R Deur, A d'Hose, N Diederich, B Domingo, JJ Epstein, MB Ewell, LA Finn, JM Fissum, KG Fonvieille, H Frois, B Frullani, S Gao, H Gao, J Garibaldi, F Gasparian, A Gilad, S Gilman, R Glamazdin, A Glashausser, C Gomez, J Gorbenko, V Hansen, JO Holmes, R Holtrop, M Howell, C Huber, GM Hyde-Wright, C Iodice, M de Jager, CW Jaminion, S Jardillier, J Jones, MK Jutier, C Kahl, W Kato, S Katramatou, AT Kelly, JJ Kerhoas, S Ketikyan, A Khayat, M Kino, K Kramer, LH Kumar, KS Kumbartzki, G Kuss, M Lavessiere, G Leone, A LeRose, JJ Liang, M Lindgren, RA Liyanage, N Lolos, GJ Lourie, RW Madey, R Maeda, K Malov, S Manley, DM Margaziotis, DJ Markowitz, P Marroncle, J Martino, J Martoff, CJ McCormick, K McIntyre, J van der Meer, RLJ Mehrabyan, S Meziani, ZE Michaels, R Miller, GW Mougey, JY Nanda, SK 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 Rowntree, D Rutledge, G Rutt, PM Saha, A Saito, T Sarty, AJ Serdarevic, A Smith, T Soldi, K Sorokin, P Souder, PA Suleiman, R Templon, JA Terasawa, T Todor, L Tsubota, H Ueno, H Ulmer, PE Urciuoli, GM Van Hoorebeke, L Vernin, P Vlahovic, B Voskanyan, H Watson, JW Weinstein, LB Wijesooriya, K Wilson, R Wojtsekhowski, BB Zainea, DG Zhang, WM Zhao, J Zhou, ZL CA Jefferson Lab Hall A Collaboration TI Measurements of the deuteron elastic structure function A(Q(2)) for 0.7 <= Q(2)<= 6.0 (GeV/c)(2) at Jefferson laboratory SO PHYSICAL REVIEW LETTERS LA English DT Article ID HIGH MOMENTUM-TRANSFER; FORM-FACTORS; SCATTERING; Q2; MODEL AB The deuteron elastic structure function A(Q(2)) has been extracted in the range 0.7 less than or equal to Q(2) less than or equal to 6.0 (GeV/c)(2) from cross section measurements of elastic electron-deuteron scattering in coincidence using the Hall A Facility of Jefferson Laboratory. The data are compared to theoretical models, based on the impulse approximation with the inclusion of meson-exchange currents, and to predictions of quark dimensional scaling and perturbative quantum chromodynamics. [S0031-9007(99)08477-X]. C1 Univ Blaise Pascal, IN2P3, F-63177 Clermont Ferrand, France. Calif State Univ Los Angeles, Los Angeles, CA 90032 USA. Duke Univ, Durham, NC 27706 USA. Florida Int Univ, Miami, FL 33199 USA. Florida State Univ, Tallahassee, FL 32306 USA. State Univ Ghent, B-9000 Ghent, Belgium. Univ Georgia, Athens, GA 30602 USA. Inst Sci Nucl, F-38026 Grenoble, France. Hampton Univ, Hampton, VA 23668 USA. Harvard Univ, Cambridge, MA 02138 USA. Ist Nazl Fis Nucl, Sez Bari, I-70126 Bari, Italy. Univ Bari, I-70126 Bari, Italy. Ist Nazl Fis Nucl, Sez Lecce, I-73100 Lecce, Italy. Ist Nazl Fis Nucl, Sez Sanita, I-00161 Rome, Italy. Ist Super Sanita, 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. MIT, Cambridge, MA 02139 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 23508 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 08855 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 Alexa, LC (reprint author), Univ Blaise Pascal, IN2P3, F-63177 Clermont Ferrand, France. RI Perrino, Roberto/B-4633-2010; Gao, Haiyan/G-2589-2011; kino, koichi/D-6173-2012; Kuss, Michael/H-8959-2012; 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; Templon, Jeffrey/0000-0002-3371-788X; Glamazdin, Alexander/0000-0002-4172-7324 NR 31 TC 95 Z9 96 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 FEB 15 PY 1999 VL 82 IS 7 BP 1374 EP 1378 DI 10.1103/PhysRevLett.82.1374 PG 5 WC Physics, Multidisciplinary SC Physics GA 167GE UT WOS:000078623500008 ER PT J AU Abbott, D Ahmidouch, A Anklin, H Arvieux, J Ball, J Beedoe, S Beise, EJ Bimbot, L Boeglin, W Breuer, H Carlini, R Chant, NS Danagoulian, S Dow, K Ducret, JE Dunne, J Ent, R Ewell, L Eyraud, L Furget, C Garcon, M Gilman, R Glashausser, C Gueye, P Gustafsson, K Hafidi, K Honegger, A Jourdan, J Kox, S Kumbartzki, G Lu, L Lung, A Mack, D Markowitz, P McIntyre, J Meekins, D Merchez, F Mitchell, J Mohring, R Mtingwa, S Mrktchyan, H Pitz, D Qin, L Ransome, R Real, JS Roos, PG Rutt, P Sawafta, R Stepanyan, S Tieulent, R Tomasi-Gustafsson, E Turchinetz, W Vansyoc, K Volmer, J Voutier, E Vulcan, W Williamson, C Wood, SA Yan, C Zhao, J Zhao, W AF Abbott, D Ahmidouch, A Anklin, H Arvieux, J Ball, J Beedoe, S Beise, EJ Bimbot, L Boeglin, W Breuer, H Carlini, R Chant, NS Danagoulian, S Dow, K Ducret, JE Dunne, J Ent, R Ewell, L Eyraud, L Furget, C Garcon, M Gilman, R Glashausser, C Gueye, P Gustafsson, K Hafidi, K Honegger, A Jourdan, J Kox, S Kumbartzki, G Lu, L Lung, A Mack, D Markowitz, P McIntyre, J Meekins, D Merchez, F Mitchell, J Mohring, R Mtingwa, S Mrktchyan, H Pitz, D Qin, L Ransome, R Real, JS Roos, PG Rutt, P Sawafta, R Stepanyan, S Tieulent, R Tomasi-Gustafsson, E Turchinetz, W Vansyoc, K Volmer, J Voutier, E Vulcan, W Williamson, C Wood, SA Yan, C Zhao, J Zhao, W CA Jefferson Lab t20 Collaboration TI Precise measurement of the deuteron elastic structure function A(Q(2)) SO PHYSICAL REVIEW LETTERS LA English DT Article ID FORM-FACTORS; SCATTERING; MOMENTUM; MODEL AB The A(Q(2)) structure function in elastic electron-deuteron scattering was measured at six momentum transfers Q(2) between 0.66 and 1.80 (GeV/c)(2) in Hall C at Jefferson Laboratory. The scattered electrons and recoil deuterons were detected in coincidence, at a fixed deuteron angle of 60.5 degrees. These new precise measurements resolve discrepancies between older sets of data. They put significant constraints on existing models of the deuteron electromagnetic structure, and on the strength of isoscalar meson exchange currents. [S0031-9007(99)08479-3]. C1 CEA Saclay, DAPNIA SPhN, F-91191 Gif Sur Yvette, France. Basel Inst Phys, Basel, Switzerland. Univ Maryland, College Pk, MD 20742 USA. UJF, ISN, IN2P3, F-38026 Grenoble, France. Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. Rutgers State Univ, Piscataway, NJ 08855 USA. MIT, Middleton, MA 01949 USA. Florida Int Univ, Miami, FL 33199 USA. Yerevan Phys Inst, Yerevan 375036, Armenia. N Carolina Agr & Technol State Univ, Greensboro, NC 27411 USA. LNS Saclay, F-91191 Gif Sur Yvette, France. IPNO, IN2P3, F-91406 Orsay, France. RP Abbott, D (reprint author), CEA Saclay, DAPNIA SPhN, F-91191 Gif Sur Yvette, France. RI McIntyre, Justin/P-1346-2014; Lu, Lanchun/E-3551-2011 OI McIntyre, Justin/0000-0002-3706-4310; NR 28 TC 70 Z9 71 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 FEB 15 PY 1999 VL 82 IS 7 BP 1379 EP 1382 DI 10.1103/PhysRevLett.82.1379 PG 4 WC Physics, Multidisciplinary SC Physics GA 167GE UT WOS:000078623500009 ER PT J AU Hegarty, SP Huyet, G McInerney, JG Choquette, KD AF Hegarty, SP Huyet, G McInerney, JG Choquette, KD TI Pattern formation in the transverse section of a laser with a large fresnel number SO PHYSICAL REVIEW LETTERS LA English DT Article ID SPATIOTEMPORAL INSTABILITIES; DYNAMICS; VORTICES; CHAOS AB We experimentally investigate pattern formation in a single-wavelength long laser cavity with a large Fresnel number. Near the laser threshold, we observe a single frequency spatially periodic structure corresponding to titled waves theoretically predicted by the Maxwell-Bloch equations. We also show the presence of secondary instabilities at other wavelengths and polarization instabilities at the same wavelength for different parameter values. [S0031-9007(99)08512-9]. C1 Natl Univ Ireland Univ Coll Cork, Dept Phys, Cork, Ireland. Sandia Natl Labs, Photon Res Dept, Albuquerque, NM 87185 USA. RP Hegarty, SP (reprint author), Natl Univ Ireland Univ Coll Cork, Dept Phys, Cork, Ireland. NR 25 TC 92 Z9 93 U1 0 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 FEB 15 PY 1999 VL 82 IS 7 BP 1434 EP 1437 DI 10.1103/PhysRevLett.82.1434 PG 4 WC Physics, Multidisciplinary SC Physics GA 167GE UT WOS:000078623500023 ER PT J AU Porcelli, F Rossi, E Cima, G Wootton, A AF Porcelli, F Rossi, E Cima, G Wootton, A TI Macroscopic magnetic islands and plasma energy transport SO PHYSICAL REVIEW LETTERS LA English DT Article ID TOKAMAK; OSCILLATIONS AB A model is presented based on the combined effects of m/n = I magnetic island dynamics, localized heat sources, large heat diffusivity along magnetic field lines, and plasma rotation, which may explain the multipeaked temperature profiles and transport barriers observed in tokamak plasmas heated by electron-cyclotron-resonant waves. [S0031-9007(99)08455-0]. C1 Politecn Torino, Ist Nazl Fis Mat, I-10129 Turin, Italy. Politecn Torino, Dept Energet, I-10129 Turin, Italy. Univ Texas, Ctr Fus Engn, Austin, TX 78712 USA. Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Porcelli, F (reprint author), Politecn Torino, Ist Nazl Fis Mat, I-10129 Turin, Italy. RI Rossi, Enrico/K-2837-2012; OI Rossi, Enrico/0000-0002-2647-3610; Porcelli, Francesco/0000-0002-3625-6417 NR 9 TC 34 Z9 34 U1 1 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 15 PY 1999 VL 82 IS 7 BP 1458 EP 1461 DI 10.1103/PhysRevLett.82.1458 PG 4 WC Physics, Multidisciplinary SC Physics GA 167GE UT WOS:000078623500029 ER PT J AU Emerson, JP Wright, DA Woodfield, BF Gordon, JE Fisher, RA Phillips, NE AF Emerson, JP Wright, DA Woodfield, BF Gordon, JE Fisher, RA Phillips, NE TI Specific Heat of YBa2Cu3O7-delta, 0 <=delta <= 0.2: Concentrations of paramagnetic centers and values of other parameters as functions of delta SO PHYSICAL REVIEW LETTERS LA English DT Article ID TEMPERATURE SPECIFIC-HEAT; DENSITY-OF-STATES; SINGLE-CRYSTALS; MAGNETIC-FIELD; SUPERCONDUCTORS; YBA2CU3O6+X; DEPENDENCE; VORTEX; TC AB The concentrations of paramagnetic centers and the values of other parameters, including the Debye temperature and the coefficient of the zero-field, temperature-proportional term, are reported as functions of delta. The concentration of paramagnetic centers does increase with increasing delta but, in striking contrast with the widely held expectation that the increase would be comparable to the increase in the concentration of O vacancies, it is as much as 2 orders of magnitude smaller. A new expression for the specific heat that takes into account the presence of spin-2 as well as spin-1/2 paramagnetic centers gives an accurate representation of the experimental data.[S0031-9007(99)08491-4]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Emerson, JP (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 27 TC 20 Z9 20 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 FEB 15 PY 1999 VL 82 IS 7 BP 1546 EP 1549 DI 10.1103/PhysRevLett.82.1546 PG 4 WC Physics, Multidisciplinary SC Physics GA 167GE UT WOS:000078623500051 ER PT J AU Wright, DA Emerson, JP Woodfield, BF Gordon, JE Fisher, RA Phillips, NE AF Wright, DA Emerson, JP Woodfield, BF Gordon, JE Fisher, RA Phillips, NE TI Low-temperature specific heat of YBa2Cu3O7-delta, 0 <=delta <= 0.2: Evidence for d-wave pairing SO PHYSICAL REVIEW LETTERS LA English DT Article ID DENSITY-OF-STATES; MAGNETIC-FIELD DEPENDENCE; SUPERCONDUCTORS; VORTEX; V3SI AB The dependence of the specific heat of YBa2CU3O7-delta on temperature (T) and magnetic field (H) shows a number of features predicted for d-wave pairing: a T-2 term for H = 0 and an (HT)-T-1/2 term for H not equal 0 and low T, with a crossover to a stronger T dependence at higher T. For all H and T, these results are consistent with a recently proposed scaling relation. Values of the parameters derived from experimental data agree with theoretical predictions.[S0031-9007(99)08481-1]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Amherst Coll, Dept Phys, Amherst, MA 01002 USA. RP Wright, DA (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 23 TC 93 Z9 94 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 FEB 15 PY 1999 VL 82 IS 7 BP 1550 EP 1553 DI 10.1103/PhysRevLett.82.1550 PG 4 WC Physics, Multidisciplinary SC Physics GA 167GE UT WOS:000078623500052 ER PT J AU Idzerda, YU Chakarian, V Freeland, JW AF Idzerda, YU Chakarian, V Freeland, JW TI Quantifying magnetic domain correlations in multilayer films SO PHYSICAL REVIEW LETTERS LA English DT Article ID GIANT MAGNETORESISTANCE; SCATTERING; FE; LAYERS AB The vertical correlation of magnetic domains in a Co/Cr/Co trilayer is statistically quantified as a function of an applied magnetic field. These measurements, used with determinations of the individual layer magnetometry curves, identify the presence of both antiferromagnetic exchange coupling and ferromagnetic dipolar couplings for different regions within the trilayer.[S0031-9007(99)08427-6]. C1 USN, Res Lab, Washington, DC 20375 USA. Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RP Idzerda, YU (reprint author), USN, Res Lab, Washington, DC 20375 USA. NR 24 TC 28 Z9 28 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 FEB 15 PY 1999 VL 82 IS 7 BP 1562 EP 1565 DI 10.1103/PhysRevLett.82.1562 PG 4 WC Physics, Multidisciplinary SC Physics GA 167GE UT WOS:000078623500055 ER PT J AU Braicovich, L van der Laan, G Ghiringhelli, G Tagliaferri, A van Veenendaal, MA Brookes, NB Chervinskii, MM Dallera, C De Michelis, B Durr, HA AF Braicovich, L van der Laan, G Ghiringhelli, G Tagliaferri, A van Veenendaal, MA Brookes, NB Chervinskii, MM Dallera, C De Michelis, B Durr, HA TI Magnetic circular dichroism in resonant Raman scattering in the perpendicular geometry at the L edge of 3d transition metal systems SO PHYSICAL REVIEW LETTERS LA English DT Article ID X-RAY-FLUORESCENCE; PHOTOEMISSION; SPECTRA; FE; EMISSION; IRON; CO; 2P AB We measured circular dichroism in resonant x-ray scattering 3d(n) --> 2p(5)3d(n+1) --> 3s(1)3d(n+l) with incidence perpendicular to the magnetization where the absorption dichroism vanishes. The advantages of photon scattering over other techniques make it possible to study a wide range of materials. The Ni L-3 dichroism in NiFe2O4 is (28 +/- 5)% in ageement with a localized model. In the metal Co the dichroism is reduced to (10.4 +/- 1)% (L-3) and (6.8 +/- 1.5)% (7.5 eV above L-3), indicating a large sensitivity to the nature of the valence states despite the fact that this spectroscopy is based on inner shell transitions.[S0031-9007(99)08431-8]. C1 Politecn Milan, Dipartimento Fis, I-20133 Milan, Italy. SERC, Daresbury Lab, Warrington WA4 4AD, Cheshire, England. European Synchrotron Radiat Facil, F-38043 Grenoble, France. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. DI Mendeleyev Inst Metrol, St Petersburg 198005, Russia. RI Ghiringhelli, Giacomo/D-1159-2014; Tagliaferri, Alberto/L-2903-2015; Durr, Hermann/F-6205-2012; van der Laan, Gerrit/Q-1662-2015 OI Ghiringhelli, Giacomo/0000-0003-0867-7748; Tagliaferri, Alberto/0000-0001-8001-1786; van der Laan, Gerrit/0000-0001-6852-2495 NR 19 TC 39 Z9 39 U1 0 U2 12 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 15 PY 1999 VL 82 IS 7 BP 1566 EP 1569 DI 10.1103/PhysRevLett.82.1566 PG 4 WC Physics, Multidisciplinary SC Physics GA 167GE UT WOS:000078623500056 ER PT J AU Kaufman, AN Tracy, ER Morehead, JJ Brizard, AJ AF Kaufman, AN Tracy, ER Morehead, JJ Brizard, AJ TI The dissipative Budden problem: Effect of converted-wave damping on primary-wave reflection SO PHYSICS LETTERS A LA English DT Article DE Budden; mode conversion; ion-hybrid wave; magnetosonic wave; tokamak; fusion plasma ID LINEAR-MODE-CONVERSION AB The Budden equation represents a double conversion, whereby a primary wave: first converts to a localized secondary wave, which then converts to a reflected primary wave. We analyze this process in phase space, to include secondary-wave damping between the two conversions, which reduces the reflection coefficient. The results are then applied to gyroresonant damping of the (secondary) ion-hybrid wave by fusion alpha-particles, suggesting a diagnostic test. (C) 1999 Elsevier Science B.V. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Coll William & Mary, Dept Phys, Williamsburg, VA 23187 USA. RP Kaufman, AN (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. OI Brizard, Alain/0000-0002-0192-6273 NR 11 TC 10 Z9 10 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 FEB 15 PY 1999 VL 252 IS 1-2 BP 43 EP 48 DI 10.1016/S0375-9601(98)00914-1 PG 6 WC Physics, Multidisciplinary SC Physics GA 202YW UT WOS:000080680700008 ER PT J AU Koshi, JM Bruno, WJ AF Koshi, JM Bruno, WJ TI Major structural determinants of transmembrane proteins identified by principal component analysis SO PROTEINS-STRUCTURE FUNCTION AND GENETICS LA English DT Article DE sequence analysis; alpha helix; hydrophobicity; beta-branched amino acids; aromatic amino acids ID AMINO-ACID SUBSTITUTION; CYTOCHROME-C-OXIDASE; CONFORMATIONAL ENTROPY; MAXIMUM-LIKELIHOOD; MEMBRANE-PROTEINS; MUTATION MATRICES; HELICAL PEPTIDES; ALPHA-HELICES; RESIDUES; ENVIRONMENT AB We identify amino acid characteristics important in determining the secondary structures of transmembrane proteins, and compare them with characteristics important for cytoplasmic proteins. Using information derived from multiple sequence alignments, we perform a principal component analysis (PCA) to identify the directions in the 20-dimensional amino acid frequency space that comprise the most variance within each protein secondary structure. These vectors represent the important position-specific properties of the amino acids for coils, turns, beta sheets, and alpha helices, As expected, the most important axis for most of the datasets was hydrophobicity, Additional axes, distinct from hydrophobicity, are surprising, especially in the case of transmembrane alpha. helices, where the effects of aromaticity and beta-branching are the next two most significant characteristics. The axis representing beta-branching also has equal importance in cytoplasmic and transmembrane helices, a finding that contrasts with some experimental results in membrane-like environments. In a further analysis, we examine trends for some of the PCA axes over averaged transmembrane alpha helices, and find interesting results for aromaticity. Proteins 1999;34:333-340, Published 1999 Wiley-Liss,Inc. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Koshi, JM (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. EM jkoshi@lanl.gov NR 33 TC 12 Z9 12 U1 1 U2 3 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0887-3585 J9 PROTEINS JI Proteins PD FEB 15 PY 1999 VL 34 IS 3 BP 333 EP 340 DI 10.1002/(SICI)1097-0134(19990215)34:3<333::AID-PROT6>3.3.CO;2-U PG 8 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 162YX UT WOS:000078376300006 PM 10024020 ER PT J AU Yeates, TO Fam, BC AF Yeates, TO Fam, BC TI Protein crystals and their evil twins SO STRUCTURE WITH FOLDING & DESIGN LA English DT Review ID MEROHEDRY AB Different types of crystal twinning are reviewed with an emphasis on how to detect the phenomenon from protein diffraction data. The recent literature and a database survey both serve as reminders to perform routine checks whenever twinning is a possibility. C1 Univ Calif Los Angeles, Dept Chem & Biochem, Los Angeles, CA 90095 USA. US DOE, Lab Struct Biol & Mol Med, Los Angeles, CA 90095 USA. RP Yeates, TO (reprint author), Univ Calif Los Angeles, Dept Chem & Biochem, 406 Hilgard Ave,Bos 951569, Los Angeles, CA 90095 USA. OI Yeates, Todd/0000-0001-5709-9839 NR 21 TC 54 Z9 55 U1 1 U2 2 PU CURRENT BIOLOGY LTD PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 0969-2126 J9 STRUCT FOLD DES JI Struct. Fold. Des. PD FEB 15 PY 1999 VL 7 IS 2 BP R25 EP R29 DI 10.1016/S0969-2126(99)80016-1 PG 5 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 179VG UT WOS:000079349800002 PM 10368291 ER PT J AU Ohrwall, G Baltzer, P Bozek, J AF Ohrwall, G Baltzer, P Bozek, J TI Synchrotron radiation excited photoelectron spectrum of H-2(+) with rotational resolution SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Letter ID ANGULAR-DISTRIBUTION; DIATOMIC-MOLECULES; PHOTO-ELECTRONS; CONTINUUM; PHOTOIONIZATION; SPECTROSCOPY; INTENSITY; LINE AB The rotational branching ratio in the photoelectron spectrum of H-2(+) has been investigated using synchrotron radiation. At the photon energy hv = 23 eV, the S (Delta N = 2) branch has a considerably higher relative intensity than when excited with Her (lambda = 584 Angstrom, hv = 2 1.218 eV) or with Ne I (lambda = 736 Angstrom, hv = 16.848 eV) radiation. C1 Univ Uppsala, Dept Phys, S-75121 Uppsala, Sweden. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Ohrwall, G (reprint author), Univ Uppsala, Dept Phys, Box 530, S-75121 Uppsala, Sweden. RI Bozek, John/E-4689-2010; Bozek, John/E-9260-2010 OI Bozek, John/0000-0001-7486-7238 NR 27 TC 5 Z9 5 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD FEB 14 PY 1999 VL 32 IS 3 BP L51 EP L56 DI 10.1088/0953-4075/32/3/028 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 170QX UT WOS:000078818500003 ER PT J AU Yamataka, H Aida, M Dupuis, M AF Yamataka, H Aida, M Dupuis, M TI One transition state leading to two product states: ab initio molecular dynamics simulations of the reaction of formaldehyde radical anion and methyl chloride SO CHEMICAL PHYSICS LETTERS LA English DT Article ID SINGLE-ELECTRON-TRANSFER; HINDERED ALKYL-HALIDES; SUBSTITUTION-REACTIONS; NUCLEOPHILIC-SUBSTITUTION; ORGANIC-CHEMISTRY; SN2 REACTIONS; MECHANISMS; POLAR; MODEL AB Ab initio molecular dynamics (MD) simulations for the reaction of formaldehyde radical anion and methyl chloride indicate that trajectories starting from a well-characterized single transition state reach either an electron-transfer (ET) product or a C-substituted S(N)2 product, The two kinds of trajectories have different characteristics. Trajectories which lead to the S(N)2 product state are simple, with C-C bond formation and C-Cl bond breaking essentially completed within 50 fs, By contrast, trajectories leading to the ET product are more complex with a sudden electron reorganization taking place around 15-30 fs; the major bonding changes and electron and spin reorganization are completed after 250 fs. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Osaka Univ, Inst Sci & Ind Res, Osaka 5670047, Japan. Natl Canc Ctr, Res Inst, Div Biophys, Chuo Ku, Tokyo 1040045, Japan. Pacific NW Natl Lab, EMLS, Richland, WA 99352 USA. RP Yamataka, H (reprint author), Osaka Univ, Inst Sci & Ind Res, Osaka 5670047, Japan. EM yamataka@snaken.osaka-u.ac.jp RI Aida, Misako/D-1670-2010 OI Aida, Misako/0000-0001-8788-1071 NR 27 TC 45 Z9 45 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD FEB 12 PY 1999 VL 300 IS 5-6 BP 583 EP 587 DI 10.1016/S0009-2614(98)01440-7 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 166BE UT WOS:000078555700011 ER PT J AU Manaa, MR Chabalowski, CF AF Manaa, MR Chabalowski, CF TI A theoretical treatment of the intersystem crossing in the spin-forbidden reaction NO(X-2 Pi)+CO(X-1 Sigma(+))-> N(S-4)+CO2(X-1 Sigma(+)(g)) SO CHEMICAL PHYSICS LETTERS LA English DT Article ID REACTION CH(X2-PI)+N2(X1-SIGMA-G+)->HCN(X1-SIGMA+)+N(4S); MECHANISM; GRADIENT; O(D-1) AB The mechanism of the spin-forbidden reaction NO(X(2)Pi) + CO(X (1)Sigma(+)) --> N(S-4) + CO2(X (1)Sigma(g)(+)) is considered. Two minimum energy points on the doublet-quartet crossing surface are reported using multireference configuration interaction (MRCI) wavefunctions. The lowest-energy crossing point has an approximate C-2v structure resembling the products N + CO2. This region lies 60 kcal/mol above the reactant channel, suggesting that the title reaction would not occur under typical combustion conditions. A higher-energy point with a linear structure is also located. Two local minima on the lowest (2)A " potential energy surface are reported at the QCISD and MRCI levels. (C) 1999 Elsevier Science B.V. All rights reserved. C1 USA, Res Lab, AMSRL WM BD, Aberdeen Proving Ground, MD 21005 USA. RP Manaa, MR (reprint author), Univ Calif Lawrence Livermore Natl Lab, Energet Mat Ctr, POB 808,L-282, Livermore, CA 94551 USA. EM manaa1@llnl.gov NR 26 TC 7 Z9 7 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD FEB 12 PY 1999 VL 300 IS 5-6 BP 619 EP 625 DI 10.1016/S0009-2614(98)01414-6 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 166BE UT WOS:000078555700016 ER PT J AU Terekhov, I Camp, T AF Terekhov, I Camp, T TI Time efficient deadlock resolution algorithms SO INFORMATION PROCESSING LETTERS LA English DT Article DE distributed systems; operating systems; resource allocation; deadlock resolution; minimum abort set C1 Fermi Natl Accelerator Lab, Comp Div, Batavia, IL 60510 USA. Colorado Sch Mines, Dept Math & Comp Sci, Golden, CO 80401 USA. RP Terekhov, I (reprint author), Fermi Natl Accelerator Lab, Comp Div, Batavia, IL 60510 USA. NR 7 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0020-0190 J9 INFORM PROCESS LETT JI Inf. Process. Lett. PD FEB 12 PY 1999 VL 69 IS 3 BP 149 EP 154 DI 10.1016/S0020-0190(98)00203-8 PG 6 WC Computer Science, Information Systems SC Computer Science GA 174NM UT WOS:000079041300010 ER PT J AU Gary, R Kim, K Cornelius, HL Park, MS Matsumoto, Y AF Gary, R Kim, K Cornelius, HL Park, MS Matsumoto, Y TI Proliferating cell nuclear antigen facilitates excision in long-patch base excision repair SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID DNA-POLYMERASE-BETA; STRUCTURE-SPECIFIC ENDONUCLEASE; DEOXYRIBOSE PHOSPHATE RESIDUES; HUMAN APURINIC ENDONUCLEASE; HUMAN FLAP ENDONUCLEASE-1; MISMATCH REPAIR; HUMAN FEN-1; PCNA; REPLICATION; BINDING AB There are two distinct pathways for the removal of modified DNA bases through base excision repair (BER) in vertebrates, Following 5' incision by AP endonuclease, the pathways diverge as two different excision mechanisms are possible, In short-patch repair, DNA polymerase beta accounts for both excision activity and single nucleotide repair synthesis. In long-patch repair, the damage-containing strand is excised by the structure-specific endonuclease FEN-1 and approximately 2-8 nucleotides are incorporated by proliferating cell nuclear antigen (PCNA)-dependent synthesis. PCNA is an accessory factor of DNA polymerases delta and epsilon that is required for DNA replication and repair. PCNA binds to FEN-1 and stimulates its nuclease activity, but the physiological significance of this interaction is unknown. The importance of the PCNA-FEN-1 interaction in BER was investigated, In a reconstituted BER assay system containing FEN-1, omission of PCNA caused the accumulation of pre-excision reaction intermediates which could be converted to completely repaired product by addition of PCNA. When dNTPs were omitted from the reaction to suppress repair synthesis, PCNA was required for the formation of excised reaction intermediates. In contrast, a PCNA mutant that could not bind to FEN-1 was unable to stimulate excision, To further study this effect, a mutant of FEN-T was identified that retained full nuclease activity but was specifically defective in binding to PCNA. The mutant FEN-1 exhibited one-tenth the specific activity of wild type FEN-1 in the reconstituted BER assay, and this repair defect was due to a kinetic block at the excision step as evidenced by the accumulation of pre-excision intermediates when dNTPs were omitted, These results indicate that PCNA facilitates excision during long-patch BER through its interaction with FEN-1. C1 Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. Fox Chase Canc Ctr, Dept Radiat Oncol, Philadelphia, PA 19111 USA. RP Gary, R (reprint author), Univ Calif Los Alamos Natl Lab, Div Life Sci, M888, Los Alamos, NM 87545 USA. RI Gary, Ronald/A-8650-2008 OI Gary, Ronald/0000-0001-5079-1953 FU NCI NIH HHS [CA63154, CA71630] NR 45 TC 130 Z9 132 U1 0 U2 3 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD FEB 12 PY 1999 VL 274 IS 7 BP 4354 EP 4363 DI 10.1074/jbc.274.7.4354 PG 10 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 166KQ UT WOS:000078575500062 PM 9933638 ER PT J AU Fouts, ET Yu, X Egelman, EH Botchan, MR AF Fouts, ET Yu, X Egelman, EH Botchan, MR TI Biochemical and electron microscopic image analysis of the hexameric E1 helicase SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID PAPILLOMAVIRUS TYPE-1 ORIGIN; SINGLE-STRANDED-DNA; LARGE T-ANTIGEN; LARGE TUMOR-ANTIGEN; BOVINE PAPILLOMAVIRUS; ESCHERICHIA-COLI; REPLICATION PROTEIN; BRANCH MIGRATION; VIRAL ORIGIN; E2 PROTEINS AB DNA replication initiator proteins bind site specifically to origin sites and in most cases participate in the early steps of unwinding the duplex. The papillomavirus preinitiation complex that assembles on the origin of replication is composed of proteins E1 and the activator protein E2, E2 is an ancillary factor that increases the affinity of E1 for the ori site through cooperative binding. Here we show that duplex DNA affects E1 (in the absence of E2) to assemble into an active hexameric structure. As a 10-base oligonucleotide can also induce this oligomerization, it seems likely that DNA binding allosterically induces a conformation that enhances hexamers, E1 assembles as a bi-lobed, presumably double hexameric structure on duplex DNA and can initiate bi-directional unwinding from an ori site. The DNA takes an apparent straight path through the double hexamers. Image analysis of E1 hexameric rings shows that the structures are heterogeneous and have either a 6- or 3-fold symmetry. The rings are about 40-50 Angstrom thick and 125 Angstrom in diameter. The density of the central cavity appears to be a variable and we speculate that a plugged center may represent a conformational flexibility of a subdomain of the monomer, to date unreported for other hexameric helicases. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Mol & Cell Biol, Berkeley, CA 94720 USA. Univ Minnesota, Sch Med, Dept Cell Biol & Neuroanat, Minneapolis, MN 55455 USA. RP Botchan, MR (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Mol & Cell Biol, Berkeley, CA 94720 USA. RI Egelman, Edward/A-2488-2009 FU NCI NIH HHS [CA30490, CA42414]; NIGMS NIH HHS [GM35269] NR 65 TC 100 Z9 101 U1 0 U2 1 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD FEB 12 PY 1999 VL 274 IS 7 BP 4447 EP 4458 DI 10.1074/jbc.274.7.4447 PG 12 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 166KQ UT WOS:000078575500073 PM 9933649 ER PT J AU Jin, ZM Jin, L Peterson, DL Lawson, CL AF Jin, ZM Jin, L Peterson, DL Lawson, CL TI Model for lentivirus capsid core assembly based on crystal dimers of EIAV p26 SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE EIAV; HIV; lentivirus; crystal structure; capsid model ID HUMAN-IMMUNODEFICIENCY-VIRUS; INFECTIOUS-ANEMIA VIRUS; CYCLOPHILIN-A; GAG GENE; PROTEIN; TYPE-1; HIV-1; DOMAIN; BINDING; VISUALIZATION AB Two crystal forms of recombinant p26 capsid protein (CA) from the equine infectious anemia virus (EIAV) have in common an antiparallel four-helix bundle dimer interface between N-terminal domains (NTDs). The dimer interface provides a lenient scaffold to accommodate the wide sequence variation in these helices within lentivirus CA. Pairs of dimers weakly associate to form exact or approximate D(2) symmetry tetramers. In one of the two crystal forms, the tetramers are linked via dimerization of C-terminal domains (CTDs). We propose that the observed NTD and CTD homodimer interactions are involved in the assembly of the lentivirus capsid. The NTD homodimer shape readily suggests a model for the mature capsid core, based on hexagonal packing with dimensions and surface topology resembling described EIAV capsid cores. Combining available data for human immunodeficiency virus and EIAV CA, we also propose an assembly pathway for maturation of the lentivirus capsid core following proteolytic cleavage of the gag polyprotein precursor. (C) 1999 Academic Press. C1 Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. SUNY Stony Brook, Dept Phys, Stony Brook, NY 11790 USA. Virginia Commonwealth Univ, Dept Biochem & Mol Biophys, Richmond, VA 23298 USA. RP Lawson, CL (reprint author), Rutgers State Univ, Dept Chem, 610 Taylor Rd, Piscataway, NJ 08854 USA. EM lawson@rutchem.rutgers.edu NR 44 TC 91 Z9 92 U1 0 U2 3 PU ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-2836 J9 J MOL BIOL JI J. Mol. Biol. PD FEB 12 PY 1999 VL 286 IS 1 BP 83 EP 93 DI 10.1006/jmbi.1998.2443 PG 11 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 168PT UT WOS:000078702000007 PM 9931251 ER PT J AU Muller, M AF Muller, M TI Product rule for gauge invariant Weyl symbols and its application to the semiclassical description of guiding centre motion SO JOURNAL OF PHYSICS A-MATHEMATICAL AND GENERAL LA English DT Article ID MAGNETIC-FIELD; WAVE-EQUATIONS; RECTILINEAR CURRENT; HAMILTONIAN THEORY; GEOMETRIC FORCES; ADIABATIC MOTION; PARTICLE; FORMULATION; POTENTIALS; MECHANICS AB We derive a product rule for gauge invariant Weyl symbols which provides a generalization of the well known Moyal formula to the case of non-vanishing electromagnetic fields. Applying our result to the guiding centre problem we expand the guiding centre Hamiltonian into an asymptotic power series with respect to both Planck's constant (h) over bar and an adiabaticity parameter already present in the classical theory. This expansion is used to determine the influence of quantum-mechanical effects on guiding centre motion. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Muller, M (reprint author), Petrinistr 7, D-97080 Wurzburg, Germany. EM mmueller@eckart.lbl.gov NR 44 TC 15 Z9 15 U1 0 U2 1 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 FEB 12 PY 1999 VL 32 IS 6 BP 1035 EP 1052 DI 10.1088/0305-4470/32/6/014 PG 18 WC Physics, Multidisciplinary; Physics, Mathematical SC Physics GA 170QY UT WOS:000078818600014 ER PT J AU Evdokimov, AG Kalb, AJ Koetzle, TF Klooster, WT Martin, JML AF Evdokimov, AG Kalb, AJ Koetzle, TF Klooster, WT Martin, JML TI Structures of furanosides: Density functional calculations and high-resolution X-ray and neutron diffraction crystal structures SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID EXACT EXCHANGE CONTRIBUTIONS; LINEAR SCALING COMPUTATION; SPIN-COUPLING CONSTANTS; AB-INITIO CALCULATION; WATER DIMER; BASIS-SETS; VIBRATIONAL ABSORPTION; ELECTRONIC-STRUCTURE; CORRELATION-ENERGY; CARBON CLUSTERS AB Highly accurate and precise crystal structures of methyl alpha-D-arabinofuranoside, methyl beta-D-ribofuranosidc, methyl alpha-D-lyxofuranoside, and methyl alpha-D-xylofuranoside have been determined at 100 K by X-ray crystallography. The structures of methyl alpha-D-arabinofuranoside and methyl beta-D-ribofuranoside have also been determined at 15 K by neutron diffraction. Equilibrium (r(e)) geometries of the same compounds were computed by means of density functional methods using a variety of exchange-correlation functionals and a sequence of basis sets. The validity of the computed results was assessed by several criteria including agreement between computed and observed bond distances and bond angles, agreement between computed and observed ring conformations, and basis set convergence of the computed geometrical parameters. Particular reference was made to computed internal hydrogen bond parameters, which are especially sensitive to the quality of the theoretical treatment. Because of the intrinsic sensitivity of the conformation of the five-membered ring to bond lengths and bond angles, molecular mechanics and small basis set SCF treatments are wholly inadequate. Local density functional theory also fails because of a tendency to strongly underestimate internal hydrogen bond distances. When the B3LYP exchange-correlation functional is used, bond lengths and bond angles agree with the neutron diffraction values to within their experimental uncertainty and the ring conformation is qualitatively correct, as long as a basis set of at least double-zeta plus polarization quality (such as cc-pVDZ) is used. Further expansion of the basis set leads to more accurate equilibrium bond lengths: and bond angles but does not appreciably affect the ring conformation. For methyl alpha-D-arabinofuranoside, methyl beta-D-ribofuranoside, and methyl alpha-D-xylofuranoside, there is very good correspondence between the best computed and observed ring conformations, even though some intermolecular hydrogen bonds in the crystal give way to internal hydrogen bonds in the predicted gas-phase structures. On the other hand, in the case of methyl alpha-D-lyxofuranoside, an O2H ... O4 internal hydrogen bond between the ring oxygen O4 and the hydroxyl hydrogen of a ring carbon (O2H) in the computed structure leads to a very large change of ring conformation from the northeast corner of the pseudorotation pathway (P = 28 degrees, crystal) to the southeast corner (P = 130 degrees, computed). C1 Weizmann Inst Sci, Dept Biol Struct, IL-76100 Rehovot, Israel. Weizmann Inst Sci, Dept Organ Chem, IL-76100 Rehovot, Israel. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Weizmann Inst Sci, Dept Biol Struct, POB 26, IL-76100 Rehovot, Israel. RI Martin, Jan/A-7457-2008 OI Martin, Jan/0000-0002-0005-5074 NR 70 TC 34 Z9 34 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD FEB 11 PY 1999 VL 103 IS 6 BP 744 EP 753 DI 10.1021/jp9837840 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 172GH UT WOS:000078914800016 ER PT J AU Uckan, T Wyatt, MS Mihalczo, JT Valentine, TE Mullens, JA Hannon, TF AF Uckan, T Wyatt, MS Mihalczo, JT Valentine, TE Mullens, JA Hannon, TF TI Cf-252-source-correlated transmission measurements for uranyl fluoride deposit in a 24-in-OD process pipe SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN AB Characterization of a hydrated uranyl fluoride (UO2F2 . bH(2)O) deposit in a 17 ft long, 24 in OD process pipe at the former Oak Ridge Gaseous Diffusion Plant was successfully performed using Cf-252-source-correlated time-of-flight (TOF) transmission measurements. These measurements of neutrons and gamma rays through the pipe from an external Cf-252 fission source were used to measure the deposit profile and its distribution along the pipe, the hydration (or H/U), and the total uranium mass. The measurements were performed with a source in an ionization chamber on one side of the pipe and detectors on the other. Scanning the pipe vertically and horizontally produced a spatial and time-dependent radiograph of the deposit in which transmitted gamma rays and neutrons were separated in time. The cross-correlation function between the source and the detector was measured with the Nuclear Weapons Identification System. After correcting for pipe effects, the deposit thickness was determined from the transmitted neutrons and H/U from the gamma rays. Results were consistent with a later intrusive observation of the shape and the color of the deposit; i.e., the deposit was annular and was on the top of the Fire at some locations, demonstrating the usefulness of this method for deposit characterization. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Instrumentat & Controls, Oak Ridge, TN 37830 USA. Univ Tennessee, Dept Nucl Engn, Knoxville, TN 37996 USA. Cent Engn Serv, Oak Ridge, TN 37831 USA. RP Uckan, T (reprint author), Oak Ridge Natl Lab, Div Instrumentat & Controls, Oak Ridge, TN 37830 USA. OI Valentine, Timothy/0000-0001-7495-7348 NR 12 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 1999 VL 422 IS 1-3 BP 26 EP 34 DI 10.1016/S0168-9002(98)01056-0 PG 9 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800007 ER PT J AU Beddingfield, DH Menlove, HO Johnson, NH AF Beddingfield, DH Menlove, HO Johnson, NH TI Neutron proportional counter design for high gamma-ray environments SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN DE He-3 neutron proportional counter; gamma-ray interactions; gamma-ray pile-up AB A parametric analysis of the performance of He-3 neutron proportional detector tubes in mixed gamma-ray/neutron environments has been performed. The objective of this study was to determine the optimum tube design configuration for minimized gamma-ray sensitivity based upon commercially available components. The parameters examined in the study were the tube wall material, the admix gas identity, the total fill pressure, and the tube lining material. The study resulted in the quantification of the limitations of typical He-3 tube designs and in the development of a new tube design which extends the usefulness of He-3 tubes in mixed gamma-ray/neutron environments. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Nonproliferat & Int Secur Div, Los Alamos, NM 87545 USA. GE Reuter Stokes Inc, Twinsburg, OH 44087 USA. RP Beddingfield, DH (reprint author), Univ Calif Los Alamos Natl Lab, Nonproliferat & Int Secur Div, POB 1663,NIS-5,MS E540, Los Alamos, NM 87545 USA. NR 1 TC 6 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 1999 VL 422 IS 1-3 BP 35 EP 40 DI 10.1016/S0168-9002(98)01057-2 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800008 ER PT J AU Loaiza, DJ AF Loaiza, DJ TI High-efficiency He-3 proportional counter for the detection of delayed neutrons SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN AB The characteristics of a high-efficiency He-3 proportional counter for the measurement of beta(i)-delayed neutrons have been examined. The detection system required for this experiment needs to meet some stringent requirements such as high-efficiency, low dead time, and gamma-insensitivity. The He-3 counter described here meets all these requirements. This detection system consists of an array of 20 He-3 tubes embedded in polyethylene. The principal operating characteristic of this proportional counter is its high efficiency. The absolute efficiency, determined with an Am/Li source, is 29.04% +/- 0.6%. The system's dead time is 0.46 +/- 0.02 mu s. It is also displacement insensitive within a range of 10 cm. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Loaiza, DJ (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 3 TC 7 Z9 8 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 43 EP 46 DI 10.1016/S0168-9002(98)01059-6 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800010 ER PT J AU Bartle, CM Haight, RC AF Bartle, CM Haight, RC TI Small inorganic scintillators as neutron detectors SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN DE inorganic scintillators; neutron detectors; NaI(Tl) scintillator; CsI(Tl) scintillator; neutron spectrum; pulse-shape discrimination ID NAI(TL) AB Small inorganic scintillators that exhibit pulse-shape differences (PSD) in response to charged particles have been investigated as possible neutron detectors in the energy range from 1 to 100 MeV, Neutrons in this energy range can induce reactions such as (n,p) and (n,alpha) in these scintillators. and the cross sections for these reactions vary with energy. Pulse-height and PSD distributions were measured as a function of neutron energy for small crystals of NaI(Tl) and CsI(Tl) at the LANSCE-WNR pulsed spallation neutron source. PSD information indicating the relative numbers of protons and alphas produced can give information about the neutron spectrum in fast-neutron radiation fields such as those encountered in space exploration. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Grp LANSCE 3, Los Alamos, NM 87545 USA. Inst Geol & Nucl Sci Ltd, Lower Hutt, New Zealand. RP Haight, RC (reprint author), Univ Calif Los Alamos Natl Lab, Grp LANSCE 3, MS H855, Los Alamos, NM 87545 USA. NR 15 TC 13 Z9 13 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 54 EP 58 DI 10.1016/S0168-9002(98)01062-6 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800013 ER PT J AU Grazioso, RF Heger, AS Ensslin, N Mayo, DR Mercer, DJ Miller, MC Russo, PA AF Grazioso, RF Heger, AS Ensslin, N Mayo, DR Mercer, DJ Miller, MC Russo, PA TI Feasibility of using boron-loaded plastic fibers for neutron detection SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN ID GLASS; SCINTILLATORS AB The results from simulations and laboratory experiments with boron-loaded plastic scintillating fibers as a nondestructive assay (NDA) tool are presented. Single and multi-clad fibers in three diameters of 0.25, 0.5, and 1 mm were examined for their application in neutron coincidence counting. For this application, the simulation results show that various configurations of boron-loaded plastic scintillating fibers have a die-away time (tau) of 12 mu s with an efficiency (epsilon) of 50%. For a comparable efficiency, He-3 proportional tubes have a typical die-away time of 50 mu s. The shortened die-away time can reduce the relative error for measurement of similar samples by up to 50%. Plastic scintillating fibers (PSF) also offer flexible configurations with the potential to discriminate between signals from gamma-ray and neutron events. Quantitative calculations and experiments have been conducted to determine the light output, evaluate the noise, quantify light attenuation, and determine neutron detection efficiency. Current experimental data support the analytical results that boron-loaded plastic fibers can detect thermal neutrons. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Grazioso, RF (reprint author), Univ Calif Los Alamos Natl Lab, MS E540, Los Alamos, NM 87545 USA. NR 23 TC 6 Z9 6 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 59 EP 63 DI 10.1016/S0168-9002(98)01063-8 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800014 ER PT J AU Reeder, PL Peurrung, AJ Hansen, RR Stromswold, DC Hensley, WK Hubbard, CW AF Reeder, PL Peurrung, AJ Hansen, RR Stromswold, DC Hensley, WK Hubbard, CW TI Detection of fast neutrons in a plastic scintillator using digital pulse processing to reject gammas SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN DE plastic scintillator; digital pulse processing; neutron-gamma discrimination AB We report on neutron-gamma discrimination in a plastic scintillator based on the time delay inherent in second and third chance neutron scattering. Because of the time delay ( approximate to 3 ns) between the first and second scattering of a neutron, calculations of garnmas and neutrons in a plastic scintillator predict that a neutron signal should be significantly broader than a pulse from a gamma event. Experimentally. we have used a fast digital oscilloscope coupled to a computer to examine individual pulses from neutron or gamma induced signals in fast scintillators coupled to a fast PMT. Individual neutron-induced signals were consistent with the predictions of our model, but gamma pulses were broader than expected. We present various tests to understand this phenomenon and discuss a way to overcome this problem. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Reeder, PL (reprint author), Pacific NW Natl Lab, MS P8-O8,POB 999, Richland, WA 99352 USA. EM paul.reeder@pnl.gov NR 4 TC 16 Z9 16 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 84 EP 88 DI 10.1016/S0168-9002(98)01068-7 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800019 ER PT J AU Miller, MC Biddle, RS Bourret, SC Byrd, RC Ensslin, N Feldman, WC Kuropatwinski, JJ Longmire, JL Krick, MS Mayo, DR Russo, PA Sweet, MR AF Miller, MC Biddle, RS Bourret, SC Byrd, RC Ensslin, N Feldman, WC Kuropatwinski, JJ Longmire, JL Krick, MS Mayo, DR Russo, PA Sweet, MR TI Neutron detection and applications using a BC454/BGO array SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN DE neutron detection; BC454/BGO detector array; scintillator; data acquisition system AB Neutron detection and multiplicity counting has been investigated using a boron-loaded plastic scintillator/bismuth germanate phoswich detector array. The boron-loaded plastic combines neutron moderation (H) and detection (B-10) at the molecular level, thereby physically coupling increasing detection efficiency and decreasing die-away time with detector volume. Separation of the phoswich response into its plastic scintillator and bismuth germanate components was accomplished on an event-by-event basis using custom integrator and timing circuits, enabling a prompt coincidence requirement between the BC454 and BGO to be used to identify neutron captures. In addition, a custom time-tag module was used to provide a time for each detector event. Time-correlation analysis was subsequently performed on the filtered event stream to obtain shift-register-type singles and doubles count rates. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Miller, MC (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663,MS E540, Los Alamos, NM 87545 USA. NR 7 TC 7 Z9 7 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 89 EP 94 DI 10.1016/S0168-9002(98)01069-9 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800020 ER PT J AU Lee, CL Zhou, XL Harmon, JF Bartholomay, RW Harker, YD Kudchadker, RJ AF Lee, CL Zhou, XL Harmon, JF Bartholomay, RW Harker, YD Kudchadker, RJ TI Thermal neutron flux mapping in a head phantom SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN ID CAPTURE THERAPY AB Boron neutron capture therapy (BNCT) is a binary cancer treatment modality in which a boron-containing compound is preferentially loaded into a tumor, followed by irradiation by thermal neutrons. In accelerator-based BNCT, neutrons are produced by charged particle-induced reactions such as Li-7(p, n)Be-7. For deeply seated brain tumors, epithermal (1 eV to 10 kev) neutrons are needed to penetrate the skull cap and subsequently thermalize at the tumor location. Cell damage in BNCT is caused by the high linear energy transfer (LET) products from the B-10(n, alpha)Li-7 reaction. Because the cross section for this reaction is of 1/upsilon character, the dose due to B-10 has essentially the same spatial distribution as the thermal neutron flux. A cylindrical acrylic head phantom (15.24 cm diameter by 21.59 cm length) has been constructed to simulate the patient's head and neck, and acrylic spacers of varying width allow placement of small (active sizes: 0.635 cm diameter by 1.27 cm length and 1.5875 cm diameter by 2.54 cm length) BF3 proportional counters at nearly all radial and axial locations. Measurements of the thermal flux have also been benchmarked with gold and indium foils (bare and cadmium covered), as well as MCNP simulations. Measurement of the thermal neutron flux using these small BF3 counters is shown to be adequate for experimentally determining the spatial, variation of the B-10 dose in head phantoms for accelerator-based BNCT. (C) 1999 Elsevier Science B.V. All rights reserved. C1 MIT, Dept Nucl Engn, Cambridge, MA 02139 USA. Idaho State Univ, Dept Phys, Pocatello, ID 83209 USA. Lockheed Martin Idaho Technol Co, INEEL, Idaho Falls, ID 83415 USA. RP Lee, CL (reprint author), MIT, Dept Nucl Engn, Cambridge, MA 02139 USA. NR 11 TC 5 Z9 5 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 106 EP 110 DI 10.1016/S0168-9002(98)01174-7 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800023 ER PT J AU Derenzo, SE Weber, MJ AF Derenzo, SE Weber, MJ TI Prospects for first-principle calculations of scintillator properties SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN DE scintillation; modeling; hole transport; ab-initio; self-trapped holes ID CSITL AB Several scintillation processes can be modeled from first principles using quantum chemistry cluster calculations and recently available high-performance computers. These processes include the formation of excitons and trapping centers, the diffusion of ionization energy (electrons and holes) through a host crystal, and the efficient capture of these carriers by an activator atom to form a luminous, non-quenched excited state. As examples of such calculations, results are presented for (1) hole transport in the known scintillator host crystal CsI, (2) hole trapping in the non-scintillator PbF2, (3) hole transport in the experimentally unexplored PbF4, and (4) the electronic nature of excited states of CsI:Tl and CsI:Na. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Derenzo, SE (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 13 TC 28 Z9 28 U1 1 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 111 EP 118 DI 10.1016/S0168-9002(99)01084-0 PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800024 ER PT J AU Dardenne, YX Wang, TF Lavietes, AD Mauger, GJ Ruhter, WD Kreek, SA AF Dardenne, YX Wang, TF Lavietes, AD Mauger, GJ Ruhter, WD Kreek, SA TI Cadmium zinc telluride spectral modeling SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN AB Cadmium zinc telluride (CZT) detectors are the highest resolution room temperature gamma-ray detectors available for isotopic analysis. As with germanium detectors, accurate isotopic analysis using spectra requires peak deconvolution. The CZT peak shapes are asymmetric, with a long low energy tail. The asymmetry is a result of the physics of the electron/hole transport in the semiconductor. An accurate model of the physics of the electron/hole transport through an electric field will allow the parameterization of the peak shapes as a function of energy. In turn this leads to the ability to perform accurate spectral deconvolution and therefore accurate isotopic analysis. The model and the peak-shape parameterization as a function of energy will be presented. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Dardenne, YX (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 8 TC 6 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 1999 VL 422 IS 1-3 BP 159 EP 163 DI 10.1016/S0168-9002(98)00947-4 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800033 ER PT J AU Prettyman, TH Hoffbauer, MA Rennie, JA Cook, S Gregory, JC George, MA Luke, PN Amman, M Soldner, SA Earnhart, JR AF Prettyman, TH Hoffbauer, MA Rennie, JA Cook, S Gregory, JC George, MA Luke, PN Amman, M Soldner, SA Earnhart, JR TI Performance of CdZnTe detectors passivated with energetic oxygen atoms SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN AB Noise caused by surface-leakage current can degrade the performance of CdZnTe spectrometers, particularly devices with closely spaced contacts such as coplanar grid detectors. In order to reduce surface leakage, we are treating CdZnTe detector surfaces with energetic, neutral oxygen atoms. Energetic oxygen atoms react with the surface to form a resistive oxide layer. Because the reaction is effective at room temperature, deleterious heating of the substrate is avoided. In most cases, leakage current and noise are shown to decrease significantly after treatment. The effect of the treatment on the performance of coplanar grid detectors is presented. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Safeguards Sci & Technol Grp, Los Alamos, NM 87545 USA. Univ Alabama, Dept Chem, Huntsville, AL 35899 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. EV Prod, Saxonburg, PA 16056 USA. RP Prettyman, TH (reprint author), Univ Calif Los Alamos Natl Lab, Safeguards Sci & Technol Grp, Mail Stop E540,NIS-5, Los Alamos, NM 87545 USA. OI Prettyman, Thomas/0000-0003-0072-2831 NR 7 TC 13 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 179 EP 184 DI 10.1016/S0168-9002(98)00951-6 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800037 ER PT J AU Doty, FP Lingren, CL Apotovsky, BA Brunsch, J Butler, JF Collins, T Conwell, RL Friesenhahn, S Gormley, J Pi, B Zhao, S Augustine, FL Bennett, BA Cross, E James, RB AF Doty, FP Lingren, CL Apotovsky, BA Brunsch, J Butler, JF Collins, T Conwell, RL Friesenhahn, S Gormley, J Pi, B Zhao, S Augustine, FL Bennett, BA Cross, E James, RB TI Multichannel CdZnTe gamma ray spectrometer SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN ID PRESSURE BRIDGMAN METHOD; NUCLEAR-MEDICINE; DETECTOR ARRAYS; X-RAY AB A 3 cm(3) multichannel gamma spectrometer for DOE applications is under development by Digirad Corporation. The device is based on a position sensitive detector packaged in a compact multi-chip module (MCM) with integrated readout circuitry. The modular, multichannel design will enable identification and quantitative analysis of radionuclides in extended sources, or sources containing low levels of activity. The MCM approach has the advantages that the modules are designed for imaging applications, and the sensitivity can be arbitrarily increased by increasing the number of pixels, i.e. adding modules to the instrument. For a high sensitivity probe, the outputs for each pixel can be corrected for gain and offset variations, and summed digitally. Single pixel results obtained with discrete low noise readout indicate energy resolution of 3 keV can be approached with currently available CdZnTe. The energy resolution demonstrated to date with MCMs for 511 keV gamma rays is 10 keV. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Digirad Corp, San Diego, CA 92126 USA. Augustine Engn, Encinitas, CA USA. Sandia Natl Labs, Livermore, CA USA. RP Lingren, CL (reprint author), Digirad Corp, 9350 Trade Pl, San Diego, CA 92126 USA. NR 14 TC 2 Z9 2 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 185 EP 189 DI 10.1016/S0168-9002(98)00952-8 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800038 ER PT J AU Lee, IY AF Lee, IY TI Gamma-ray tracking detectors SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN AB A gamma-ray tracking detector is a new concept for a detector array composed of about 100 highly segmented Ge detector elements. The detector would give the energy and the position of all the interaction points and by using the angle-energy relation of the Compton scattering, the scattering sequence of the gamma rays can be reconstructed. Such a detector will have a high efficiency and a good peak-to-background ratio. Research and development are being carried in the production of highly segmented Ge detectors, understanding the signal, and development of tracking algorithms. Recent progress indicated that this type of detector system appears to be feasible and would have a large impact on a wide variety of physics. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Lee, IY (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 0 TC 93 Z9 93 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 195 EP 200 DI 10.1016/S0168-9002(98)01093-6 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800040 ER PT J AU Prettyman, TH AF Prettyman, TH TI Method for mapping charge pulses in semiconductor radiation detectors SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN ID TRANSPORT AB An efficient method for determining the distribution of charge pulses produced by semiconductor detectors is presented. The method is based on a quasi-steady-state model for semiconductor detector operation. A complete description of the model and the underlying assumptions are given. Mapping of charge pulses is accomplished by solving an adjoint carrier continuity equation. The solution of the adjoint equation yields Green's function, a time- and position-dependent map that contains all possible charge pulses that can be produced by the detector for charge generated at discrete locations (e.g., by gamma-ray interactions). Because the map is generated by solving a single, time-dependent problem, the potential for reduction in computational effort over direct mapping methods is significant, particularly for detectors with complex electrode structures. In this paper, the adjoint model is presented and the mapping method is illustrated for a simple case. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Safeguards Sci & Technol Grp, Los Alamos, NM 87545 USA. RP Prettyman, TH (reprint author), Univ Calif Los Alamos Natl Lab, Safeguards Sci & Technol Grp, NIS-5,Mail Stop E540, Los Alamos, NM 87545 USA. OI Prettyman, Thomas/0000-0003-0072-2831 NR 13 TC 38 Z9 38 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 232 EP 237 DI 10.1016/S0168-9002(98)01100-0 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800047 ER PT J AU Lavietes, AD Mauger, GJ Anderson, EH AF Lavietes, AD Mauger, GJ Anderson, EH TI Electromechanically cooled germanium radiation detector system SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN AB We have successfully developed and fielded an electromechanically cooled germanium radiation detector (EMc-HPGe) at Lawrence Livermore National Laboratory (LLNL). This detector system was designed to provide optimum energy resolution, long lifetime, and extremely reliable operation for unattended and portable applications, For most analytical applications, high purity germanium (HPGe) detectors are the standard detectors of choice, providing an unsurpassed combination of high energy resolution performance and exceptional detection efficiency. Logistical difficulties associated with providing the required liquid nitrogen (LN) for cooling is the primary reason that these systems are found mainly in laboratories. The EMC-HPGe detector system described in this paper successfully provides HPGe detector performance in a portable instrument that allows for isotopic analysis in the field. It incorporates a unique active vibration control system that allows the use of a Sunpower Stirling cycle cryocooler unit without significant spectral degradation from microphonics. All standard isotopic analysis codes, including MGA and MGA + + [1], GAMANL[2], GRPANL[3] and MGAU[4], typically used with HPGe detectors can be used with this system with excellent results. Several national and international Safeguards organisations including the International Atomic Energy Agency (IAEA) and U.S, Department of Energy (DOE) have expressed interest in this system. The detector was combined with custom software and demonstrated as a rapid Field Radiometric Identification System (FRIS) for the U.S. Customs Service [5]. The European Communities' Safeguards Directorate (EURATOM) is field-testing the first Safeguards prototype in their applications. The EMC-HPGe detector system design, recent applications, and results will be highlighted. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. CSA Engn, Palo Alto, CA 94303 USA. RP Lavietes, AD (reprint author), Univ Calif Lawrence Livermore Natl Lab, 7000 East Ave L-352, Livermore, CA 94551 USA. NR 5 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 1999 VL 422 IS 1-3 BP 252 EP 256 DI 10.1016/S0168-9002(98)01104-8 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800051 ER PT J AU Cho, HS Park, IJ Hong, WS Perez-Mendez, V Kadyk, J AF Cho, HS Park, IJ Hong, WS Perez-Mendez, V Kadyk, J TI Utilization of a thin columnar cesium iodide (CsI) layer in gas avalanche microdetector SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN DE columnar cesium iodide; gas avalanche microdetector ID LOW-PRESSURE; EMISSION; CHAMBER AB A thin (200-300 mu m) layer of columnar cesium iodide (CsI) crystals has been coupled to a conventional microstrip gas chamber. This layer provides the dominant source of electron production by incident charged particles in gas avalanche microdetectors, and is expected to make a significant improvement in spatial and time resolution, and detection efficiency, with respect to particle's angle of incidence. The CsI layer also makes the chamber useful for X- or gamma-ray detection with good position accuracy. In this paper, measurements are presented of signal enhancement due to the columnar CsI layer, and the efficiency versus angle. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Engn, Berkeley, CA 94720 USA. RP Cho, HS (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Phys, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 9 TC 8 Z9 8 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 269 EP 272 DI 10.1016/S0168-9002(98)00955-3 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800054 ER PT J AU Cho, HS Hong, WS Kadyk, J Perez-Mendez, V AF Cho, HS Hong, WS Kadyk, J Perez-Mendez, V TI Performance of microdot (MDOT) detectors with conductive coating of doped amorphous silicon carbide (a-Si : C : H) SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN DE microdot detectors; defocusing; conductive coating; doped amorphous silicon carbide ID MICROSTRIP GAS-CHAMBERS AB A conductive coating of doped amorphous silicon carbide (a-Si:C:H) has been used in the fabrication of microdot (MDOT) detectors, to minimize the defocusing, away from the anodes, of the drifting primary electrons. This defocusing is caused by the existence of the readout line passing below the insulating layer. The defocusing effect and other effects of the conductive coating on the performance of these detectors fabricated in this way have been investigated. (C) 1999 Elsevier. Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Phys, Berkeley, CA 94720 USA. RP Cho, HS (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Phys, 1 Cyclotron Rd, Berkeley, CA 94720 USA. 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 296 EP 299 DI 10.1016/S0168-9002(98)00961-9 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800060 ER PT J AU Blair, J Beckedahl, D Kammeraad, J Schmid, G AF Blair, J Beckedahl, D Kammeraad, J Schmid, G TI Spatial resolution attainable in germanium detectors by pulse shape analysis SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN DE germanium detectors; gamma-ray interactions; pulse-shape AB There are several applications for which it is desirable to calculate the locations and energies of individual gamma-ray interactions within a high purity germanium (HPGe) detector. These include gamma-ray imaging and Compton suppression, With a segmented detector this can be accomplished by analyzing the pulse shapes of the signals from the various segments. We examine the fundamental limits to the spatial resolution attainable with this approach. The primary source of error is the series noise of the field effect transistors (FETs) at the inputs of the charge amplifiers. We show how to calculate the noise spectral density at the output of the charge amplifiers due to an optimally selected FET. This calculation is based only on the detector capacitance and a noise constant for the FET technology. We show how to use this spectral density to calculate the uncertainties in parameters, such as interaction locations and energies, that are derived from pulse shape analysis using maximum likelihood estimation (MLE) applied to filtered and digitized recordings of the charge signals. Example calculations are given to illustrate our approach. Experimental results are given that demonstrate that one can construct complete systems, from detector through data analysis, that come near the theoretical limits. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Bechtel Nevada, N Las Vegas, NV 89130 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Blair, J (reprint author), Bechtel Nevada, N Las Vegas, NV 89130 USA. NR 10 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 331 EP 336 DI 10.1016/S0168-9002(98)00976-0 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800067 ER PT J AU Odell, DMC Bushart, BS Harpring, LJ Moore, FS Riley, TN AF Odell, DMC Bushart, BS Harpring, LJ Moore, FS Riley, TN TI Zero dead time spectroscopy without full charge collection SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MI DE zero dead time spectroscopy; gamma monitoring instrument; digital signal processor; digital sampling AB The Savannah River Technology Center has built a remote gamma monitoring instrument which employs data sampling techniques rather than full charge collection to perform energy spectroscopy without instrument dead time. The raw, unamplified anode output of a photomultiplier tube is directly coupled to the instrument to generate many digital samples during the charge collection process, so that all pulse processing is done in the digital domain. The primary components an a free running, 32 MSPS, 10-bit A/D, a field programmable gate array, FIFO buffers, and a digital signal processor (DSP). Algorithms for pulse integration, pile-up rejection, and other shape-based criteria are being developed in DSP code for migration into the gate array. Spectra taken with a 2 in NaI(Tl) detector have been obtained at rates as high as 59 000 counts per second without dead time with peak resolution at 662 keV measuring 7.3%. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Savannah River Technol Ctr, Aiken, SC 29808 USA. RP Savannah River Technol Ctr, Bldg 773-A,Savannah River Site, Aiken, SC 29808 USA. NR 9 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 EI 1872-9576 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 1999 VL 422 IS 1-3 BP 363 EP 367 DI 10.1016/S0168-9002(98)00984-X PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800073 ER PT J AU Schmid, GJ Beckedahl, D Blair, JJ Friensehner, A Kammeraad, JE AF Schmid, GJ Beckedahl, D Blair, JJ Friensehner, A Kammeraad, JE TI HPGe Compton suppression using pulse shape analysis SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN DE HPGe Compton suppression; pulse shape analysis ID CONTINUUM SUPPRESSION; DETECTORS AB We present a new technique for High Purity Germanium (HPGe) Compton suppression using pulse shape analysis (PSA). The novel aspect of our approach involves a complete unfolding of the charge pulse shape into discrete components associated with individual gamma-ray interactions. The information thus acquired is then used to favorably reject Compton escape events. The advantage of the current PSA approach, as compared with ether recent approaches, is the potential to reject not only single-site escape events, but also multiple-site escape events. Here we discuss the details of our algorithm, and present experimental results from a real-time implementation on a 5 cm x 5 cm HPGe. An experimental comparison with a standard EGO suppressor is also shown. In addition, we discuss the improvements to the current PSA approach which are possible if one can highly segment the outer contact of the HPGe. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Bechtel Nevada, N Las Vegas, NV 89130 USA. RP Schmid, GJ (reprint author), Univ Calif Lawrence Livermore Natl Lab, L-231, Livermore, CA 94550 USA. NR 9 TC 16 Z9 16 U1 0 U2 6 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 368 EP 372 DI 10.1016/S0168-9002(98)00985-1 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800074 ER PT J AU Miko, D Estep, RJ Rawool-Sullivan, MW AF Miko, D Estep, RJ Rawool-Sullivan, MW TI An innovative method for extracting isotopic information from low-resolution gamma spectra SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN DE gross-count material basis set (GC-MBS); gamma-ray spectra; isotopes AB A method is described for the extraction of isotopic information from attenuated gamma-ray spectra using the gross-count material basis set (GC-MBS) model. This method solves for the isotopic composition of an unknown mixture of isotopes attenuated through an absorber of unknown material. For binary isotopic combinations the problem is nonlinear in only one variable and is easily solved using standard line optimization techniques. Results are presented for NaI spectrum analyses of various binary combinations of enriched uranium, depleted uranium, low burnup Pu, Cs-137, and Ba-133 attenuated through a suite of absorbers ranging in Z from polyethylene through lead. The GC-MBS method results are compared to those computed using ordinary response function fitting and with a simple net peak area method. The GC-MBS method was found to be significantly more accurate than the other methods over the range of absorbers and isotopic blends studied. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Adv Nucl Technol, Los Alamos, NM 87545 USA. RP Rawool-Sullivan, MW (reprint author), Univ Calif Los Alamos Natl Lab, Adv Nucl Technol, NIS-6,POB 1663,Mail Stop J562, Los Alamos, NM 87545 USA. NR 5 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 1999 VL 422 IS 1-3 BP 433 EP 437 DI 10.1016/S0168-9002(98)01112-7 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800086 ER PT J AU Helmer, RG AF Helmer, RG TI International decay data evaluation project SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN ID GAMMA-RAY INTENSITIES; U-238; PA-234M AB Basic concepts of, and information from, radionuclide decay are used in many applications. Many of these applications require a knowledge of half-lives and radiation energies and emission probabilities. For over 50 years, people have compiled and evaluated measured data and combined these with theoretical results with the goal of obtaining the best values of these quantities. This has resulted in numerous sets of recommended values, many of which still have scientific, historical, or national reasons for existing. These sets show varying degrees of agreement and disagreement in the quoted values and varying lime lags in incorporating new and improved experimental results. A new international group made up of six evaluators from four countries was formed in 1995 to carry out evaluations for radionuclides of importance in applications; it is expected that the results will become an authoritative and widely accepted set of decay data. This Decay Data Evaluation Project has selected nuclides to be evaluated, the methodology to be used, and a review and approval process. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Lockheed Martin Idaho Technol Co, Idaho Natl Engn & Evironm Lab, Idaho Falls, ID 83415 USA. RP Helmer, RG (reprint author), Lockheed Martin Idaho Technol Co, Idaho Natl Engn & Evironm Lab, Idaho Falls, ID 83415 USA. NR 47 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 518 EP 524 DI 10.1016/S0168-9002(98)01078-X PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800103 ER PT J AU Helmer, RG van der Leun, C AF Helmer, RG van der Leun, C TI Recommended standards for gamma-ray energy calibration SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN ID AVOGADRO CONSTANT; REMEASUREMENT AB A consistent set of gamma-ray energies, generally with uncertainties of less than 10 ppm, has been prepared for use in the energy calibration of gamma-ray spectra. The energy scale used for the previously recommended standards (1979) has been modified to take into account subsequent adjustments in the fundamental constants (-7.71 ppm) and in the gamma-ray wavelengths deduced from a revised estimate of the lattice spacing of Si crystals (+1.91 ppm). On this revised energy scale, the strong line from Au-198 has an energy of 411 802.05 +/- 0.17 eV, which is 2.4 eV (or 5.80 ppm) lower than the 1979 value. A significant improvement has come from the reduction in the uncertainty in the wavelength-to-keV conversion factor from 2.6 to 0.3 ppm. The gamma-ray energies reported here are all on this 'wavelength' scale and range from 25 to 6129 keV. The criteria for the selection of gamma rays to include are described. The list of gamma-ray energies recommended for calibration, especially for Ge semiconductor detectors, has values for about 260 gamma-rays from 50 radionuclides and two (n, gamma) reactions. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Lockheed Martin Idaho Technol Co, Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. Univ Utrecht, RJ Van de Graaff Lab, NL-3508 TA Utrecht, Netherlands. RP Helmer, RG (reprint author), Lockheed Martin Idaho Technol Co, Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. NR 26 TC 12 Z9 13 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 525 EP 531 DI 10.1016/S0168-9002(98)01079-1 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800104 ER PT J AU Feldman, WC Barraclough, BL Fuller, KR Lawrence, DJ Maurice, S Miller, MC Prettyman, TH Binder, AB AF Feldman, WC Barraclough, BL Fuller, KR Lawrence, DJ Maurice, S Miller, MC Prettyman, TH Binder, AB TI The Lunar Prospector gamma-ray and neutron spectrometers SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN AB Gamma-ray and neutron spectrometers (GRS and NS, respectively) are included in the payload complement of Lunar Prospector (LP) that is currently orbiting the Moon. Specific objectives of the GRS are to map abundances of O, Si, Fe, Ti, U, Th, K, and perhaps, Mg, Al, and Ca, to depths of about 20 cm. Those of the NS are to search for water ice to depths of about 50 cm near the lunar poles and to map regolith maturity. The designs of both spectrometers are described and their performance in both the laboratory and in lunar orbit are presented. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Lunar Res Inst, Gilroy, CA 95020 USA. RP Feldman, WC (reprint author), Univ Calif Los Alamos Natl Lab, MS-D466, Los Alamos, NM 87545 USA. RI Lawrence, David/E-7463-2015; OI Lawrence, David/0000-0002-7696-6667; Prettyman, Thomas/0000-0003-0072-2831 NR 2 TC 76 Z9 79 U1 1 U2 9 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 562 EP 566 DI 10.1016/S0168-9002(98)00934-6 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800110 ER PT J AU Hsu, HH Kearfott, KJ AF Hsu, HH Kearfott, KJ TI Criticality dosimetry using a sulfur disk and a priori neutron spectral knowledge SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN AB This gaper proposes the design of a new approach to criticality accident dosimetry, which uses a priori knowledge of the neutron spectra for criticality accident conditions, and depends upon accurate detector spectral response characterization and environmental modeling. The sulfur disk was selected as a potential neutron detector, for neutrons of higher energies. Several sulfur disks were exposed to a critical Godiva experiment, the spectral response function determined using Monte Carlo methods, and the activity determined using knowledge of the known criticality spectrum. The new method, possibly with two or more different detectors to measure other energy ranges, holds promise as a practical approach to neutron criticality dosimetry. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Hlth Phys Measurements Grp, Los Alamos, NM 87545 USA. Univ Michigan, Dept Nucl Engn & Radiol Sci, Ann Arbor, MI 48109 USA. RP Hsu, HH (reprint author), Univ Calif Los Alamos Natl Lab, Hlth Phys Measurements Grp, MS G761, Los Alamos, NM 87545 USA. RI Kearfott, Kimberlee/G-2467-2014 OI Kearfott, Kimberlee/0000-0002-8698-0913 NR 7 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 1999 VL 422 IS 1-3 BP 626 EP 628 DI 10.1016/S0168-9002(98)00972-3 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800123 ER PT J AU Aufderheide, MB Vantine, H Egan, PO Morgan, D AF Aufderheide, MB Vantine, H Egan, PO Morgan, D TI X-ray imaging and reconstruction of a detonation front SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN DE X-ray radiography; high-explosive LX-14; simulation AB We performed an axi-symmetric, two-dimensional experiment on the high-explosive LX-14. We used low-energy X-rays to image the detonation front at multiple times. The experiment provides a stringent test of radiographic unfolding techniques and has the potential to provide high-pressure data on the equation of state of the explosive. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, B Div, Livermore, CA 94551 USA. RP Aufderheide, MB (reprint author), Univ Calif Lawrence Livermore Natl Lab, B Div, POB 808,L-170, Livermore, CA 94551 USA. NR 9 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 1999 VL 422 IS 1-3 BP 704 EP 708 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800137 ER PT J AU Woodring, M Souza, D Tipnis, S Waer, P Squillante, M Entine, C Ziock, KP AF Woodring, M Souza, D Tipnis, S Waer, P Squillante, M Entine, C Ziock, KP TI Advanced radiation imaging of low-intensity gamma-ray sources SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN AB Imaging gamma-ray sources and distributions of low intensity is difficult using current commercially available radiation imagers, Radiation Monitoring Devices, Inc. has carried out the research and development necessary to construct a novel, compact radiation-imaging device, RADCAM, for low-intensity applications. The device consists of a position-sensitive photomultiplier tube (PSPMT) coupled to a CsI(Na) scintillation crystal, which is an excellent candidate for such applications due to its high light output. A tungsten coded-aperture mask, placed in front of the scintillator, creates a gamma-ray intensity pattern across the face of the crystal. The PSPMT detects the resulting scintillation pattern and the analog output signals are captured and converted to digital signals by the RMD PSPMT interface card. The digital data is stored and processed by a portable personal computer. The gamma-ray "shadowgram" is then mathematically decoded to yield the original source image. The pseudo-color radiation-source image is overlaid on a video picture of the same area captured by a high-resolution CCD. The combined image is displayed on screen as an accurate map of radioactive gamma-ray sources in the physical environment. Data acquisition and image display are controlled by the IMager Acquisition and Graphical-user-interface Environment (IMAGE), a Windows-NT program developed for the imager. (C) 1999 Published by Elsevier Science B.V. All Fights reserved. C1 Radiat Monitoring Devices Inc, Instrument Res & Dev Grp, Watertown, MA 02172 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Woodring, M (reprint author), Radiat Monitoring Devices Inc, Instrument Res & Dev Grp, 44 Hung St, Watertown, MA 02172 USA. NR 7 TC 29 Z9 29 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 709 EP 712 DI 10.1016/S0168-9002(98)01022-5 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800138 ER PT J AU Hofstetter, KJ Cable, PR Beals, DM AF Hofstetter, KJ Cable, PR Beals, DM TI Field analyses of tritium at environmental levels SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN DE monitoring; aqueous; real-time AB An automated, remote system to analyze tritium in aqueous solutions at environmental levels has been tested and has demonstrated laboratory quality tritium analysis capability in near real time. The field deployable tritium analysis system (FDTAS) consists of a novel multi-port autosampler, an on-line water purification system, and a prototype stop-flow liquid scintillation counter (LSC) which can be remotely controlled for unmanned operation. Backgrounds of similar to 1.5 counts/min in the tritium channel are routinely measured with a tritium detection efficiency of similar to 25% for the custom 11 ml cell. A detection limit of < 0.3 pCi/ml has been achieved for 100-min counts using a 50:50 mixture of sample and cocktail. To assess the long-term performance characteristics of the FDTAS, a composite sampler was installed on the Savannah River, downstream of the Savannah River Site, and collected repetitive 12-hour composite samples over a 14 day period. The samples were analyzed using the FDTAS and in the laboratory using a standard bench-top LSC. The results of the tritium analyses by the FDTAS and by the laboratory LSC were consistent for comparable counting times at the typical river tritium background levels (similar to 1 pCi/ml). (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Westinghouse Savannah River Co, Savannah River Lab, Aiken, SC 29808 USA. RP Hofstetter, KJ (reprint author), Westinghouse Savannah River Co, Savannah River Lab, Aiken, SC 29808 USA. NR 6 TC 1 Z9 1 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 761 EP 766 DI 10.1016/S0168-9002(98)00993-0 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800148 ER PT J AU Russ, WR Valentine, JD Rooney, BD Gross, KC AF Russ, WR Valentine, JD Rooney, BD Gross, KC TI Fluid transfer concentration of airborne radioxenon to enhance monitoring capabilities SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN AB To facilitate airborne radioxenon monitoring, a xenon concentration method with potential advantages over current technology in simplicity, size, and cost has been developed. The concentration technique is based on the preferential absorption of heavy noble gases (krypton, xenon, and radon) by certain organic fluids. To implement this concentration technique, a radioxenon monitoring system requires three integrated sub-systems: (1) an absorption sub-system; (2) a degassing sub-system; and (3) a radiation detection sub-system. This study is focused on the characterization and optimization of the first two sub-systems. Measurements using a small prototype absorption tower have indicated a xenon removal factor of approximately 50% and the specific concentration at saturation of certain organic fluids to be about 3.5 times the specific concentration in the sampled air. Various techniques for degassing have been investigated, including heating, purging, agitation and vacuum. Ultrasonic agitation of a thin film in a strong vacuum has been shown to be an effective means of degassing the transfer fluid continuously. Various schemes for integrating ail of the sub-systems are considered. Combining the small prototype absorption and degassing sub-systems should result in a transfer efficiency of about 33%. Each stage of an optimized concentration system should be able to increase the radioxenon concentration by approximately one order of magnitude. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Cincinnati, Dept MINE, Cincinnati, OH 45221 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP Valentine, JD (reprint author), Univ Cincinnati, Dept MINE, Cincinnati, OH 45221 USA. NR 6 TC 2 Z9 3 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 820 EP 825 DI 10.1016/S0168-9002(98)01005-5 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800160 ER PT J AU Helmer, RG Gehrke, RJ Carpenter, MV AF Helmer, RG Gehrke, RJ Carpenter, MV TI Three types of photon detectors for in situ measurements SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN DE photon detectors; X- and gamma-ray; in situ measurements; radionuclide AB The authors have been involved in the calibration and use of three types of gamma- and X-ray detectors for in situ measurements of soil contamination. These three detectors are an N-type, thin-window Ge semiconductor detector (5.0 cm diam. x 2.0 cm deep), a plastic scintillator (30.5 cm x 30.5 cm x 3.8 cm thick), and an array of six CaF2 detectors (each 7.6 cm x 7.6 cm x 0.15 cm thick). The latter two detectors have been used with scanning systems that allow significant areas (say, > 100 m(2)) to be surveyed completely with the aid of either laser-based triangulation or a global positioning system (GPS) to record the precise position for each measurement. Typically, these systems scan at a rate of 15-30 cm/s which allows an area of 100 m(2) to covered with the plastic scintillator in about 15 min. The data are telemetered or transferred via RS232 protocol to a computer, providing operators with real-time mapping of the area surveyed and of the measured detector count rate. The "effciencies" of these detectors have been determined by a combination of measurements of calibrated planar sources and Monte Carlo transport calculations for a variety of source sizes and depths in soil, as well as by comparing these field measurements with independent laboratory sample analysis. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Lockheed Martin Idaho Technol Co, Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Helmer, RG (reprint author), Lockheed Martin Idaho Technol Co, Idaho Natl Engn & Environm Lab, POB 1625, Idaho Falls, ID 83415 USA. NR 4 TC 3 Z9 3 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 826 EP 831 DI 10.1016/S0168-9002(98)01006-7 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800161 ER PT J AU Moss, CE Goeller, RM Milligan, DF Valencia, JE Zinn, J AF Moss, CE Goeller, RM Milligan, DF Valencia, JE Zinn, J TI Remote sensing of radiation SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN DE remote sensing; optical techniques; gamma ray; differential absorption lidar (DIAL) AB The distance at which gamma-ray or neutron radiation from moderately intense radiation sources can be detected in air by conventional detectors is limited to less than about 100 m. We have investigated the possibility of increasing this range by measuring the effect of the radiation on the air near the source. The radiation ionizes the surrounding air causing chemical reactions to occur which form new molecular species that might be sensed with remote sensing optical techniques. We have calculated the molar fraction as a function of time of the species formed in air by irradiation with (113)Ci source of Co-60. After 10(4) s, we find the dominant ones are O-3, 5 x 10(-7); N2O, 4 x 10(-7); HNO3, 3 x 10(-7): a HO2NO2, 2 x 10(-7); and NO2, 5 x 10(-8). All of these species have complex absorption curves in the infrared (IR) range 2-12 mu m. In addition, O-3 has a broad absorption band in the ultraviolet (UV) range at 257 nm. The IR absorption spectrum is particularly interesting because the low attenuation by air of the interrogating IR radiation might allow detection of the generated chemical species in air near a radiation source at large distances using differential absorption lidar (DIAL). The higher attenuation over the UV range limits its useful range to perhaps 100 m. We describe our setups to measure the molar fraction by measuring the optical absorption with IR and UV spectrometers. We present responses or limits that are below the calculated values for the dominant species and suggest some reasons. We conclude that for moderately intense sources of gamma rays and neutrons, currently available optical techniques, while sensitive, are not sensitive enough for this application. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Nonproliferat & Int Secur Div, Los Alamos, NM 87545 USA. RP Moss, CE (reprint author), Univ Calif Los Alamos Natl Lab, Nonproliferat & Int Secur Div, Los Alamos, NM 87545 USA. NR 6 TC 7 Z9 7 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 832 EP 836 DI 10.1016/S0168-9002(98)01120-6 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800162 ER PT J AU Bowyer, SM Bowyer, TW AF Bowyer, SM Bowyer, TW TI A silicon array detector for high-energy betas SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN DE on-site inspection system; silicon array NaI coupled detection system; gamma-ray spectroscopy; radionucides AB The detection of significant levels of certain gamma and beta emitting isotopes could allow on-site inspection teams working under the Comprehensive Test Ban Treaty to localize probable vent and fissure locations. Thus, sophisticated drilling and radionuclide measurements could then be made more effectively allowing for a higher probability of correctly identifying a nuclear event. In order to address this need we have developed a silicon array coupled with a Nal for detecting gammas high-energy betas, and beta-gamma coincidences. The pursuit of this detection method is now viable since large-area. high-purity silicon wafers are now commercially available making this layered, large-area technique technically and economically feasible. We have designed, constructed, and tested a prototype detector system and we will present out initial test data. Published by Elsevier Science B.V. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Bowyer, SM (reprint author), Pacific NW Natl Lab, POB 999,P8-08, Richland, WA 99352 USA. NR 3 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 1999 VL 422 IS 1-3 BP 837 EP 840 DI 10.1016/S0168-9002(98)01119-X PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800163 ER PT J AU Staples, P Prettyman, T Lestone, J AF Staples, P Prettyman, T Lestone, J TI Imaging of heterogeneous materials by prompt gamma-ray neutron activation analysis SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN AB We have used a Tomographic Gamma Scanner (TGS) to produce tomographic Prompt Gamma-Ray Neutron Activation Imaging of heterogeneous matrices [T.H. Prettyman, R.J. Estep, G.A. Sheppard, Trans. Am. Nucl. Sec. 69 (1993) 183-184]. The TGS was modified by the addition of graphite reflectors that contain isotopic neutron sources for sample interrogation. We are in the process of developing the analysis methodology necessary for a quantitative assay of large containers of heterogeneous material. This nondestructive analysis technique can be used for material characterization and the determination of neutron assay correction factors. The most difficult question to be answered is the determination of the source to sample coupling term. To assist in the determination of the coupling term we have obtained images for a range of samples that are very well characterized; such as, homogenous pseudo one-dimensional samples to three-dimensional heterogeneous samples. We then compare the measurements to Monte Carlo N-particle calculations. For an accurate quantitative measurement it is also necessary to determine the sample gamma-ray self attenuation at higher gamma-ray energies, namely pair production should be incorporated into the analysis codes. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Staples, P (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 1999 VL 422 IS 1-3 BP 906 EP 908 DI 10.1016/S0168-9002(98)01041-9 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800176 ER PT J AU Hsu, HH Kearfott, KJ AF Hsu, HH Kearfott, KJ TI Effects of neutron source selection on land-mine detection efficiency SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN AB One proposed method of land-mine detection is based on measurements of the 10.8 MeV photons from the N-14(n, gamma) reaction. In this study, simulations of the photon production efficiencies for nitrogenous explosive material (TNT), buried in soil having variable moisture content, were completed for different published neutron spectra. Monte Carlo simulations were performed with MCNP with a cylindrical geometry of TNT considered as target material and with neutron energies ranging from thermal to 20 MeV. The numbers of N-14(n, gamma) reactions in TNT were tallied to obtain response functions. To find the effectiveness of different neutron sources, response functions were folded with the neutron spectra. Response curves reveal that higher water content increases response for fast neutrons, and reduces response for slow neutrons. Lower energy neutron sources, i.e. D(d, n) or Cf-252, are more suitable than higher energy neutron sources such as Am-241-Be or T(d, n). Although its advantages disappear with increasing depth, the usage of moderating spheres of CH2 increases the signal significantly when compared with a bare source, while also reducing neutron dose to workers. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Hlth Phys Measurements Grp, Los Alamos, NM 87545 USA. Univ Michigan, Dept Nucl Engn & Radiol Sci, Ann Arbor, MI 48109 USA. RP Hsu, HH (reprint author), Univ Calif Los Alamos Natl Lab, Hlth Phys Measurements Grp, MS G761, Los Alamos, NM 87545 USA. RI Kearfott, Kimberlee/G-2467-2014 OI Kearfott, Kimberlee/0000-0002-8698-0913 NR 3 TC 8 Z9 8 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 914 EP 917 DI 10.1016/S0168-9002(98)01043-2 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800178 ER PT J AU Kim, KH Klann, RT Raju, BB AF Kim, KH Klann, RT Raju, BB TI Fast neutron radiography for composite materials evaluation and testing SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN AB Fast neutron radiography (FNR) employs recoil protons produced by energetic neutrons in a hydrogen-rich plastic sheet through elastic scattering. FNR provides distinctive advantages in non-destructive evaluation (NDE) of thick composite material. Other traditional techniques, such as X-ray and thermal neutron radiography (TNR), do not meet FNRs capabilities in this area. FNR is also capable of detecting flaws and moisture in composite materials significantly greater than 25 mm thick and can penetrate all of the materials that X-rays and TNR cannot. The FNR images are produced directly during exposure; the neutrons create recoil protons, the protons activate a scintillator screen, and the converted images can be viewed within minutes after exposure. Some results of FNR images of composite material produced at Argonne National Laboratory-West-FNR Facility (14.3 MeV) are presented and its imaging techniques are discussed along with their resolution limitations. (C) 1999 Elsevier Science B.V. All rights reserved. C1 N Carolina Cent Univ, Durham, NC 27707 USA. Argonne Natl Lab, Idaho Falls, ID 83403 USA. USA, TACOM, TARDEC, Warren, MI 48397 USA. RP Kim, KH (reprint author), N Carolina Cent Univ, Durham, NC 27707 USA. NR 4 TC 9 Z9 13 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 FEB 11 PY 1999 VL 422 IS 1-3 BP 929 EP 932 DI 10.1016/S0168-9002(98)01048-1 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800182 ER PT J AU Galloway, AM Spencer, CA Anderson, CW Allalunis-Turner, MJ AF Galloway, AM Spencer, CA Anderson, CW Allalunis-Turner, MJ TI Differential stability of the DNA-activated protein kinase catalytic subunit mRNA in human glioma cells SO ONCOGENE LA English DT Article DE DNA-PKcs; radiation sensitivity; M059J cell line; mRNA stability; transcription rates ID STRAND BREAK REPAIR; MESSENGER-RNA DECAY; NONSENSE CODONS; TRANSLATION; RADIATION; REGION; GENE; TRANSCRIPTION; SITE; KU AB DNA-dependent protein kinase (DNA-PK) functions in double-strand break repair and immunoglobulin [V(D)J] recombination. We previously established a radiation-sensitive human cell line, M059J, derived from malignant glioma, which lacks the catalytic subunit (DNA-PKcs) of the DNA-PK multiprotein complex, Although previous Northern blot analysis failed to detect the DNA-PKcs transcript in these cells, we show here through quantitative studies that the transcript is present, albeit at greatly reduced ( similar to 20x) levels. Sequencing revealed no genetic alteration in either the promoter region, the kinase domain, or the 3' untranslated region of the DNA-PKcs gene to account for the reduced transcript levels. Nuclear run-on transcription assays indicated that the rate of DNA-PKcs transcription in M059J and DNA-PKcs proficient cell lines was similar, but the stability of the DNA-PKcs message in the M059J cell line was drastically ( similar to 20x) reduced. Furthermore, M059J cells lack an alternately spliced DNA-PKcs transcript that accounts for a minor (5 - 20%) proportion of the DNA-PKcs message in all other cell lines tested. Thus, alterations in DNA-PKcs mRNA stability and/or the lack of the alternate mRNA may result in the loss of DNA-PKcs activity, This finding has important implications as DNA-PKcs activity is essential to cells repairing damage induced by radiation or radiomimetric agents. C1 Univ Alberta, Cross Canc Inst, Edmonton, AB T6G 1Z2, Canada. Univ Alberta, Dept Oncol, Edmonton, AB T6G 1Z2, Canada. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Allalunis-Turner, MJ (reprint author), Univ Alberta, Cross Canc Inst, Edmonton, AB T6G 1Z2, Canada. FU NIGMS NIH HHS [GM52825] NR 35 TC 14 Z9 14 U1 0 U2 0 PU STOCKTON PRESS PI BASINGSTOKE PA HOUNDMILLS, BASINGSTOKE RG21 6XS, HAMPSHIRE, ENGLAND SN 0950-9232 J9 ONCOGENE JI Oncogene PD FEB 11 PY 1999 VL 18 IS 6 BP 1361 EP 1368 DI 10.1038/sj.onc.1202433 PG 8 WC Biochemistry & Molecular Biology; Oncology; Cell Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Oncology; Cell Biology; Genetics & Heredity GA 165FW UT WOS:000078510900012 PM 10022818 ER PT J AU Witala, H Glockle, W Golak, J Huber, D Kamada, H Nogga, A AF Witala, H Glockle, W Golak, J Huber, D Kamada, H Nogga, A TI Scaling properties of the longitudinal and transversal asymmetries of the (n)over-right-arrow(d)over-right-arrow total cross section SO PHYSICS LETTERS B LA English DT Article ID 3-NUCLEON; FORCE AB The longitudinal and transversal asymmetries of the total (n) over right arrow d cross section are calculated. Four modern nucleon-nucleon interactions: AV18. CD Bonn, NijmI and NijmII, give different predictions for these observables. When the three-nucleon Hamiltonian is supplemented by the 2 pi-exchange Tucson-Melbourne three-nucleon force (3NF), individually adjusted with each particular NN potential to reproduce the experimental triton binding energy, all predictions practically coincide. We propose to check this scaling behavior experimentally in order to get a clear signal for 3NF effects in the low energy three-nucleon continuum. Connected to that is the proposal to measure the energy at which the longitudinal asymmetry goes through zero. This energy is shifted by about 400 keV when 3NF's are acting. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Ruhr Univ Bochum, Inst Theoret Phys 2, D-44780 Bochum, Germany. Jagiellonian Univ, Inst Phys, PL-30059 Krakow, Poland. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Witala, H (reprint author), Ruhr Univ Bochum, Inst Theoret Phys 2, D-44780 Bochum, Germany. RI Nogga, Andreas/A-3354-2008 OI Nogga, Andreas/0000-0003-2156-748X NR 13 TC 14 Z9 14 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 FEB 11 PY 1999 VL 447 IS 3-4 BP 216 EP 220 DI 10.1016/S0370-2693(99)00002-7 PG 5 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 169XC UT WOS:000078773900003 ER PT J AU Adams, J Alavi-Harati, A Albuquerque, IF Alexopoulos, T Arenton, M Arisaka, K Averitte, S Barker, AR Bellantoni, L Bellavance, A Belz, J Ben-David, R Bergman, DR Blucher, E Bock, GJ Bown, C Bright, S Cheu, E Childress, S Coleman, R Corcoran, MD Corti, G Cox, B Crisler, MB Erwin, AR Field, S Ford, R Graham, G Graham, J Hagan, K Halkiadakis, E Hanagaki, K Hazumi, M Hidaka, S Hsiung, YB Jejer, V Jennings, J Jensen, DA Johnson, PT Kessler, R Kobrak, HGE LaDue, J Lath, A Ledovskoy, A McManus, AP Mikelsons, P Mochida, S Monnier, E Nakaya, T Nauenberg, U Nelson, KS Nguyen, H O'Dell, V Pang, M Pordes, R Prasad, V Qiao, C Quinn, B Ramberg, EJ Ray, RE Ronzhin, A Roodman, A Sadamoto, M Schnetzer, S Senyo, K Shanahan, P Shawhan, PS Slater, W Solomey, N Somalwar, SV Stone, RL Suzuki, I Swallow, EC Swanson, RA Taegar, SA Tesarek, RJ Thomson, GB Toale, PA Tripathi, A Tschirhart, R Wah, YW White, HB Whitmore, J Winstein, B Winston, R Wu, JY Yamanaka, T Zimmerman, ED AF Adams, J Alavi-Harati, A Albuquerque, IF Alexopoulos, T Arenton, M Arisaka, K Averitte, S Barker, AR Bellantoni, L Bellavance, A Belz, J Ben-David, R Bergman, DR Blucher, E Bock, GJ Bown, C Bright, S Cheu, E Childress, S Coleman, R Corcoran, MD Corti, G Cox, B Crisler, MB Erwin, AR Field, S Ford, R Graham, G Graham, J Hagan, K Halkiadakis, E Hanagaki, K Hazumi, M Hidaka, S Hsiung, YB Jejer, V Jennings, J Jensen, DA Johnson, PT Kessler, R Kobrak, HGE LaDue, J Lath, A Ledovskoy, A McManus, AP Mikelsons, P Mochida, S Monnier, E Nakaya, T Nauenberg, U Nelson, KS Nguyen, H O'Dell, V Pang, M Pordes, R Prasad, V Qiao, C Quinn, B Ramberg, EJ Ray, RE Ronzhin, A Roodman, A Sadamoto, M Schnetzer, S Senyo, K Shanahan, P Shawhan, PS Slater, W Solomey, N Somalwar, SV Stone, RL Suzuki, I Swallow, EC Swanson, RA Taegar, SA Tesarek, RJ Thomson, GB Toale, PA Tripathi, A Tschirhart, R Wah, YW White, HB Whitmore, J Winstein, B Winston, R Wu, JY Yamanaka, T Zimmerman, ED CA KTeV Collaboration TI Search for the decay K-L ->pi(0)nu(nu)over-bar SO PHYSICS LETTERS B LA English DT Article ID MATRIX AB We report on a search for the rare decay K-L --> pi(0)nu(nu)over-bar in the KTeV experiment at Fermilab. We searched for two-photon events whose kinematics were consistent with an isolated pi(o) coming from the decay K-L --> pi(0)nu(nu)over-bar. One candidate event was observed, which was consistent with the expected level of background. An upper limit on the branching ratio was determined to be B(K-L --> pi(o)nu(nu)over-bar) less-than 1.6 x 10(-6) at the 90% confidence level. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Virginia, Dept Phys, Charlottesville, VA 22901 USA. Univ Arizona, Tucson, AZ 85721 USA. Univ Calif Los Angeles, Los Angeles, CA 90095 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Univ Colorado, Boulder, CO 80309 USA. Elmhurst Coll, Elmhurst, IL 60126 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Osaka Univ, Toyonaka, Osaka 560, Japan. Rice Univ, Houston, TX 77005 USA. Rutgers State Univ, Piscataway, NJ 08855 USA. Univ Virginia, Inst Nucl & Particle Phys, Charlottesville, VA 22901 USA. Univ Wisconsin, Madison, WI 53706 USA. RP Adams, J (reprint author), Univ Virginia, Dept Phys, Charlottesville, VA 22901 USA. RI Albuquerque, Ivone/H-4645-2012 OI Albuquerque, Ivone/0000-0001-7328-0136 NR 10 TC 19 Z9 19 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 FEB 11 PY 1999 VL 447 IS 3-4 BP 240 EP 245 DI 10.1016/S0370-2693(98)01593-7 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 169XC UT WOS:000078773900007 ER PT J AU Ruebush, SD Couch, RE Thevuthasan, S Fadley, CS AF Ruebush, SD Couch, RE Thevuthasan, S Fadley, CS TI X-ray photoelectron diffraction study of thin Cu films grown on clean Ru(0001) and O-precovered Ru(0001) SO SURFACE SCIENCE LA English DT Article DE copper; epitaxy; low energy electron diffraction; oxygen; ruthenium; single-crystal epitaxy; surface structure, morphology, roughness, and topography; X-ray photoelectron diffraction ID AUGER-ELECTRON DIFFRACTION; METAL-METAL INTERFACES; SURFACE; OXYGEN; CU(111); RELAXATION; LEED; ADSORPTION; SCATTERING; RECONSTRUCTION AB We have studied the epitaxial growth modes and near-surface interlayer relaxation of thin Cu films on Ru(0001) using X-ray photoelectron diffraction ( XPD), measuring experimental Cu 2p(3/2) (E(kin) = 556 eV) and Ru 3d (E(kin) = 1206 eV) intensities over one-third of the nearly full 2 pi solid angle above the surface for Cu coverages from submonolayer up to 40 monolayers. Reference Cu 2p(3/2) data for a clean Cu(lll) surface have also been obtained From Naumovie et al. and in our laboratory. These data have been compared to single scattering cluster (SSC) and more accurate multiple scattering cluster (MSC) calculations via a sum of five R-factors to derive precise structural information. MSC calculations are found to give a more accurate description for layers of greater than or equal to 4 ML thickness, and comparisons of experiment and theory are also improved by allowing more accurately for the effective degree of angular averaging involved. Calculations for thicker layers are also found to converge by similar to 5 ML. Our analysis indicates that the first Cu layer grows pseudomorphically on Ru(0001), in agreement with prior studies. An R-factor analysis comparing MSC and SSC calculations to experimental results further indicates that the Cu-Ru interlayer spacing at 1 monolayer (ML) is about 2.15 Angstrom, in excellent agreement with prior low-energy ion scattering (LEIS) and low-energy electron diffraction (LEED) experimental studies, as well as with prior linearized augmented plane-wave (LAPW) calculations. At higher coverages, comparison of our data to SSC and MSC calculations for various atomic clusters indicates that the short-range structure is fee Cu(111)-like, but with significant interlayer contraction which persists up to greater than or equal to 5 ML coverage. Prior STM work by Behm et al. has shown a series of misfit dislocation structures in the top layer of the Cu film at higher coverages from 2 to 4 ML. Our data indicate that these misfit dislocation structures thread to the Cu/Ru interface rather than occurring only in the top Cu layer or layers. An R-factor comparison of the more accurate MSC calculations to experiment also indicates that the ratio of the Cu-Cu interlayer distance (d(perpendicular to)) to the Cu-Cu in-plane nearest-neighbor distance (d(//)), d(perpendicular to)/d(//) = 0.729 +/- 0.034 at 2 ML, and reaches 0.777 +/- 0.020 by 25 ML. For reference, the bulk value is d(perpendicular to)/d(//) = 0.816, and the analysis of experimental data for Cu(111) yields 0.801 +/- 0.035, in good agreement with this value and prior LEED studies. This analysis shows that there is significant interlayer contraction for very thin Cu layers, and that it persists (at least in the top few layers, to which XPD is the most sensitive) for longer than would be expected on the basis of a prior theoretical analysis using the 2D Frenkel-Kontorova model by Hamilton and Foiles, as used to estimate d(perpendicular to)/d(//) via either a constant atomic-volume assumption or elasticity theory. In addition, the Cu overlayer grows in two possible orientations rotated by 180 degrees on the Ru(0001) surface, with a preference towards one of the two possible orientations at certain coverages. Finally, we have investigated the effect of oxygen preadsorbed on the Ru(0001) surface on the growth of the Cu overlayer. For this case, we find that all of the oxygen floats on top of the Cu in a highly disordered configuration, and that the oxygen promotes multilayer or island growth relative to growth on the clean Ru surface up to at least 3 ML coverage, rather than acting as a surfactant promoting smoother growth. (C) 1999 Published by Elsevier Science B.V, All rights reserved. C1 Univ Calif Davis, Davis, CA 95616 USA. Pacific NW Lab, Mol Sci Res Ctr, Richland, WA 99352 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Fadley, CS (reprint author), Univ Calif Davis, Davis, CA 95616 USA. NR 63 TC 12 Z9 12 U1 2 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 FEB 11 PY 1999 VL 421 IS 3 BP 205 EP 236 DI 10.1016/S0039-6028(98)00741-9 PG 32 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 168ZC UT WOS:000078722200004 ER PT J AU Brown, AJL Korber, BT Condra, JH AF Brown, AJL Korber, BT Condra, JH TI Associations between amino acids in the evolution of HIV type 1 protease sequences under indinavir therapy SO AIDS RESEARCH AND HUMAN RETROVIRUSES LA English DT Article ID HUMAN-IMMUNODEFICIENCY-VIRUS; REDUCED SENSITIVITY; DRUG-RESISTANCE; INHIBITORS; VARIANTS; SELECTION; MUTATIONS; LAMIVUDINE; ZIDOVUDINE; GENE AB Significant diversity exists in amino acid sequences encoding HIV-1 protease in individuals naive for protease inhibitors, which could influence the rate of evolution of resistance. High-level resistance to indinavir requires multiple substitutions among at least 11 amino acid sites, and no single substitution was observed in all of 29 resistant isolates obtained from patients on long-term indinavir monotherapy, We have analyzed the evolution of PR in these sequences. The divergence from the baseline amino acid sequence by week 24 was 4%, increasing more than 7% by week 60, The mean difference between sequences from different patients at baseline was 6% (3-9%), rising to 10% after 40 weeks (3-16%), although at all time points nonsynonymous substitutions were less frequent than synonymous nucleotide changes, Analysis of associations between variants at different amino acid sites using a mutual information statistic revealed four pairs of sites to be significantly associated. In three cases these associations included residue 82, Clusters of baseline and week 24 amino acid sequences identified by maximum parsimony did not correlate significantly with the IC95 to indinavir, although a weak correlation of baseline clusters with phenotype at the week 24 time point was suggested. C1 Univ Edinburgh, Inst Cell Anim & Populat Biol, Ctr HIV Res, Edinburgh EH9 3JN, Midlothian, Scotland. Univ Calif Los Alamos Natl Lab, GRP T10, Los Alamos, NM 87545 USA. Merck Res Labs, Dept Antiviral Res, W Point, PA 19486 USA. RP Brown, AJL (reprint author), Univ Edinburgh, Inst Cell Anim & Populat Biol, Ctr HIV Res, Waddington Bldg,W Mains Rd, Edinburgh EH9 3JN, Midlothian, Scotland. RI Leigh Brown, Andrew/F-3802-2010; OI Korber, Bette/0000-0002-2026-5757 FU NIAID NIH HHS [YI-AI4058-03]; PHS HHS [Y01-70001] NR 29 TC 24 Z9 24 U1 0 U2 0 PU MARY ANN LIEBERT INC PUBL PI LARCHMONT PA 2 MADISON AVENUE, LARCHMONT, NY 10538 USA SN 0889-2229 J9 AIDS RES HUM RETROV JI Aids Res. Hum. Retrovir. PD FEB 10 PY 1999 VL 15 IS 3 BP 247 EP 253 DI 10.1089/088922299311420 PG 7 WC Immunology; Infectious Diseases; Virology SC Immunology; Infectious Diseases; Virology GA 166QJ UT WOS:000078588300004 PM 10052755 ER PT J AU Chakhovskoi, AG Hunt, CE Malinowski, ME AF Chakhovskoi, AG Hunt, CE Malinowski, ME TI Gas desorption electron stimulated during operation of field emitter phosphor screen pairs SO DISPLAYS LA English DT Article DE field emission displays; field emitter array; phosphor ID COMBUSTION SYNTHESIS; DEPOSITION; EMISSION AB Gas desorption from field emitter array (FEA) cathode and phosphor screen anode in a flat panel display during lifetime operation can affect cathode electron emission and degrade display performance and uniformity. We have measured the outgassing products from selected FEA-phosphor pairs in an ultrahigh vacuum system equipped with a calibrated quadrople residual gas analyzer. Different low voltage phosphors and blank anodes were studied. A Spindt-type FEA was used as the electron source. A unique carousel was used so the desorption from all these different anodes could be measured without intervening vacuum breaks. this allowed the desorption from the different anodes to be directly compared to each other. Quantitative outgassing rates are given and the implications of the results for the pumping of the flat panel and emission from the FEAs an discussed. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Davis, Dept Elect & Comp Engn, Davis, CA 95616 USA. Sandia Natl Labs, Livermore, CA 94550 USA. RP Chakhovskoi, AG (reprint author), Univ Calif Davis, Dept Elect & Comp Engn, Davis, CA 95616 USA. NR 13 TC 3 Z9 3 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0141-9382 J9 DISPLAYS JI Displays PD FEB 10 PY 1999 VL 19 IS 4 BP 179 EP 184 DI 10.1016/S0141-9382(98)00048-1 PG 6 WC Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic; Instruments & Instrumentation; Optics SC Computer Science; Engineering; Instruments & Instrumentation; Optics GA 179BP UT WOS:000079303900005 ER PT J AU Zywicz, E Puso, MA AF Zywicz, E Puso, MA TI A general conjugate-gradient-based predictor-corrector solver for explicit finite-element contact SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING LA English DT Article DE contact; Lagrangian multiplier; finite element ID IMPACT; ALGORITHMS; FRICTION; DYNAMICS; ENERGY AB A Lagrange-multiplier based approach is presented for the general solution of multi-body contact within an explicit finite element framework. The technique employs an explicit predictor step to permit the detection of interpenetration and then utilizes a corrector step, whose solution is obtained with a pre-conditioned matrix-free conjugate gradient projection method, to determine the Lagrange multipliers necessary to eliminate the predicted penetration. The predictor-corrector algorithm is developed for deformable bodies based upon the central difference method, and for rigid bodies from momentum and energy conserving approaches. Both frictionless and Coulomb-based frictional contact idealizations are addressed. The technique imposes no time-step constraints and quickly mitigates velocity discontinuities across closed interfaces. Special attention is directed toward contact between rigid bodies. Algorithmic moment arms conserve the translational and angular momentums of the system in the absence of external loads. Elastic collisions are captured with a two-phase predictor-corrector approach and a geometrically approximate velocity jump criterion. The first step solves the inelastic contact problem and identifies inactive constraints between rigid bodies, while the second step generates the necessary velocity jump condition on the active constraints. The velocity criterion is shown to algorithmically preserve the system kinetic energy for two unconstrained rigid bodies. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Univ Calif Lawrence Livermore Natl Lab, Struct Appl Mech Grp, Livermore, CA 94550 USA. RP Zywicz, E (reprint author), Univ Calif Lawrence Livermore Natl Lab, Struct Appl Mech Grp, POB 808, Livermore, CA 94550 USA. NR 19 TC 8 Z9 8 U1 2 U2 4 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0029-5981 J9 INT J NUMER METH ENG JI Int. J. Numer. Methods Eng. PD FEB 10 PY 1999 VL 44 IS 4 BP 439 EP 459 DI 10.1002/(SICI)1097-0207(19990210)44:4<439::AID-NME509>3.3.CO;2-H PG 21 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA 159KK UT WOS:000078171300001 ER PT J AU Colella, P Dorr, MR Wake, DD AF Colella, P Dorr, MR Wake, DD TI A conservative finite difference method for the numerical solution of plasma fluid equations SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE models; numerical methods; finite difference methods; ionized gas flow in electromagnetic fields; plasmic flow AB This paper describes a numerical method for the solution of a system of plasma fluid equations. The fluid model is similar to those employed in the simulation of high-density, low-pressure plasmas used in semiconductor processing. The governing equations consist of a drift-diffusion model of the electrons, together with an internal energy equation, coupled via Poisson's equation to a system of Euler equations for each ion species augmented with electrostatic force, collisional, and source/sink terms. The time integration of the full system is performed using an operator splitting that conserves space charge and avoids dielectric relaxation timestep restrictions. The integration of the individual ion species and electrons within the time-split advancement is achieved using a second-order Godunov discretization of the hyperbolic terms, modified to account for the significant role of the electric field in the propagation of acoustic waves, combined with a backward Euler discretization of the parabolic terms. Discrete boundary conditions are employed to accommodate the plasma sheath boundary layer on underresolved grids. The algorithm is described for the case of a single Cartesian grid as the first step toward an implementation on a locally refined grid hierarchy in which the method presented here may be applied on each refinement level. (C) 1999 Academic Press. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Colella, P (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, 1 Cyclotron Rd,MS 50D, Berkeley, CA 94720 USA. EM MiloDorr@llnl.gov NR 17 TC 24 Z9 25 U1 1 U2 3 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 EI 1090-2716 J9 J COMPUT PHYS JI J. Comput. Phys. PD FEB 10 PY 1999 VL 149 IS 1 BP 168 EP 193 DI 10.1006/jcph.1998.6136 PG 26 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 164NQ UT WOS:000078470800009 ER PT J AU Putirka, K AF Putirka, K TI Melting depths and mantle heterogeneity beneath Hawaii and the East Pacific Rise: Constraints from Na/Ti and rare earth element ratios SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Review ID MIDOCEAN RIDGE BASALTS; SCIENTIFIC DRILLING PROJECT; MARBLE-CAKE MANTLE; MID-ATLANTIC RIDGE; MAUNA-KEA VOLCANO; LOIHI SEAMOUNT; OCEAN-RIDGE; HEAT-FLOW; LIQUIDUS EQUILIBRIA; PERIDOTITE KLB-1 AB Mantle melting calculations are presented that place constraints on the mineralogy of the basalt source region and partial melting depths for oceanic basalts. Melting depths are obtained from pressure-sensitive mineral-melt partition coefficients for Na, Ti, Hf, and the rare earth elements (REE). Melting depths are estimated by comparing model aggregate melt compositions to natural basalts from Hawaii and the East Pacific Rise (EPR). Variations in melting depths in a peridotite mantle are sufficient to yield observed differences in Na/Ti, Lu/Hf, and Sm/Yb between Hawaii and the EPR. Initial melting depths of 95-120 km are calculated for EPR basalts, while melting depths of 200-400 km are calculated for Hawaii, indicating a mantle that is 300 degrees C hotter at Hawaii. Some isotope ratios at Hawaii are correlated with Na/Ti, indicating vertical stratification to isotopic heterogeneity in the mantle; similar comparisons involving EPR lavas support a layered mantle model. Abundances of Na, Ti, and REE indicate that garnet pyroxenite and eclogite are unlikely source components at Hawaii and may be unnecessary at the EPR. The result that some geochemical features of oceanic lavas appear to require only minor variations in mantle mineral proportions (2% or less) may have important implications regarding the efficiency of mantle mixing. Heterogeneity required by isotopic studies might be accompanied by only subtle differences in bulk composition, and material that is recycled at subduction zones might not persist as mineralogically distinct mantle components. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Putirka, K (reprint author), Univ Calif Lawrence Livermore Natl Lab, L-202,7000 E Ave, Livermore, CA 94550 USA. EM putirka1@llnl.gov NR 111 TC 54 Z9 56 U1 1 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD FEB 10 PY 1999 VL 104 IS B2 BP 2817 EP 2829 DI 10.1029/1998JB900048 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 165YL UT WOS:000078549400012 ER PT J AU Mauthe, RJ Dingley, KH Leveson, SH Freeman, SPHT Turesky, RJ Garner, RC Turteltaub, KW AF Mauthe, RJ Dingley, KH Leveson, SH Freeman, SPHT Turesky, RJ Garner, RC Turteltaub, KW TI Comparison of DNA-adduct and tissue-available dose levels of MeIQx in human and rodent colon following administration of a very low dose SO INTERNATIONAL JOURNAL OF CANCER LA English DT Article ID ACCELERATOR MASS-SPECTROMETRY; HETEROCYCLIC AROMATIC-AMINES; COVALENT BINDING; HUMAN LIVER; EXPOSURE; FOOD; CANCER; RISK AB [2-C-14]2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MelQx) was administered orally (304 ng/kg body-weight dose based upon an average 70-kg-body-weight subject) to 5 human colon-cancer patients (58 to 84 years old), as well as to F344 rats and B6C3F1 mice. Colon tissue was collected from the human subjects at surgery and from the rodents 3.5 to 6 hr after administration. Colon DNA-adduct levels and tissue available doses were measured by accelerator mass spectrometry (AMS), The mean levels of MelQx in the histologically normal colon tissue were not different among the human (97 +/- 26 pg MelQx/g), rat(133 +/- 15 pg/g) or mouse (78 +/- IO pg/g) tissues; and no difference existed between the levels detected in human normal and tumor tissue (101 +/- 15 pg/g), Mean DNA-adduct levels in normal human colon (26 +/- 4 adducts/10(12) nucleotides) were significantly greater(p < 0.01) than in rats (17.1 +/- 1 adduct/10(12) nucleotides) or mice (20.6 +/- 0.9 adduct/10(12) nucleotides). No difference existed in adduct levels between normal and tumor tissue in humans. These results show that MelQx forms DNA adducts in human colon at low dose, and that the human colon may be more sensitive to the effects of MelQx than that of mice or rats. (C) 1999 Wiley-Liss, Inc. C1 Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Mol & Struct Biol Div, Livermore, CA 94551 USA. Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94551 USA. York Dist Hosp, York, N Yorkshire, England. Nestec Ltd, Nestle Res Ctr, CH-1000 Lausanne, Switzerland. Univ York, Dept Biol, Jack Birch Univ Environm Carcinogenesis, York YO1 5DD, N Yorkshire, England. RP Turteltaub, KW (reprint author), Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Mol & Struct Biol Div, POB 808,L-452, Livermore, CA 94551 USA. RI Freeman, Stewart/C-3290-2012 OI Freeman, Stewart/0000-0001-6148-3171 FU NCI NIH HHS [CA55861] NR 22 TC 47 Z9 47 U1 0 U2 2 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0020-7136 J9 INT J CANCER JI Int. J. Cancer PD FEB 9 PY 1999 VL 80 IS 4 BP 539 EP 545 DI 10.1002/(SICI)1097-0215(19990209)80:4<539::AID-IJC10>3.0.CO;2-C PG 7 WC Oncology SC Oncology GA 159AH UT WOS:000078149300010 PM 9935154 ER PT J AU Murat, M Grest, GS Kremer, K AF Murat, M Grest, GS Kremer, K TI Statics and dynamics of symmetric diblock copolymers: A molecular dynamics study SO MACROMOLECULES LA English DT Article ID LAMELLAR PHASE-TRANSITIONS; MONTE-CARLO SIMULATION; BLOCK-COPOLYMER; MICROPHASE SEPARATION; DISORDER TRANSITION; CHAIN DIFFUSION; JUNCTION POINTS; POLYMER BLENDS; THIN-FILMS; MELTS AB Extensive molecular dynamics simulations are carried out to study static and dynamic properties of symmetric diblock copolymer melts, both in the disordered and in the lamellar phases. The lamellar phase is constructed using the natural lamellar spacing, determined from constant pressure simulations. The non-Gaussian character of the chains in the disordered phase is demonstrated and quantified. In the lamellar phase, the density profile of the separate blocks, as well as the interface thickness are determined as a function of chain length N and AB interaction parameter <(epsilon)over tilde>, and compared with experiments and other theoretical results. Single chain and single block form factors indicate that the chains in the lamellar phase are distorted into stick-like objects. Our results in the disordered phase show a stronger dependence of the diffusion constant on the chain length than observed in previous simulations. Diffusion within the lamellar plane for systems with chains of length N less than or equal to 100 monomers is found to be almost independent of <(epsilon)over tilde>, in agreement with the predictions by Barrat and Fredrickson for Rouse chains. Diffusion perpendicular to the lamellae is exponentially suppressed with increasing <(epsilon)over tilde>. Simulations with even longer chains (up to N = 400 monomers) indicate that, in the strong segregation regime, chain stretching lowers the entanglement density and shifts the tube motion characteristic of the chain dynamics in homogeneous melts of long chains toward much longer chains. C1 Exxon Res & Engn Co, Corp Res Sci Labs, Annandale, NJ 08801 USA. Max Planck Inst Polymerforsch, D-55021 Mainz, Germany. Soreq Nucl Res Ctr, IL-81800 Yavne, Israel. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Grest, GS (reprint author), Exxon Res & Engn Co, Corp Res Sci Labs, Annandale, NJ 08801 USA. RI Kremer, Kurt/G-5652-2011; MPIP, Theory/I-9884-2014 NR 57 TC 93 Z9 94 U1 6 U2 32 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD FEB 9 PY 1999 VL 32 IS 3 BP 595 EP 609 DI 10.1021/ma981512p PG 15 WC Polymer Science SC Polymer Science GA 166HK UT WOS:000078570000010 ER PT J AU Cole, DH Shull, KR Baldo, P Rehn, L AF Cole, DH Shull, KR Baldo, P Rehn, L TI Dynamic properties of a model polymer/metal nanocomposite: Gold particles in poly(tert-butyl acrylate) SO MACROMOLECULES LA English DT Article ID GLASS-TRANSITION TEMPERATURE; DIBLOCK COPOLYMERS; FILMS; SIZE; NANOCLUSTERS; MICRODOMAINS; POLYSTYRENE; ADSORPTION; INTERFACE; DIFFUSION AB A combination of methods has been used to study the dynamic properties of a nanocomposite consisting of evaporated gold particles embedded in poly(tert-butyl acrylate). Rutherford backscattering spectrometry was used to measure the diffusion coefficients of the gold particles and of the polymer molecules; dewetting experiments were used to probe the viscosity of thin films with and without gold particles. The gold particles diffused with a temperature dependence similar to the temperature dependence of the polymer viscosity, but with hydrodynamic radii that greatly exceeded the actual radii of the gold particles. The gold particles also increased the viscosity of a low molecular weight polymer film by a factor of 4. Our interpretation of these results is that long-lived polymer bridges between individual gold particles stabilize clusters with dimensions of approximately 50 nm. A geometrical model of the bridging process was also developed. Results from this model can readily be applied to homogeneous nanoparticle dispersions in polymeric matrixes. C1 Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Shull, KR (reprint author), Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. RI Shull, Kenneth/B-7536-2009 NR 50 TC 89 Z9 89 U1 0 U2 31 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD FEB 9 PY 1999 VL 32 IS 3 BP 771 EP 779 DI 10.1021/ma981252b PG 9 WC Polymer Science SC Polymer Science GA 166HK UT WOS:000078570000032 ER PT J AU Gildemeister, JM Lee, AT Richards, PL AF Gildemeister, JM Lee, AT Richards, PL TI A fully lithographed voltage-biased superconducting spiderweb bolometer SO APPLIED PHYSICS LETTERS LA English DT Article ID NOISE AB We describe the fabrication and characterization of superconducting transition-edge bolometers for astrophysical applications at far-infrared and mm wavelengths. The sensor is voltage biased and the current is measured with a superconducting quantum interference ammeter. Strong negative electrothermal feedback keeps the sensor temperature nearly constant, reduces the response time significantly, and improves linearity. It also makes the responsivity relatively insensitive to changes in optical background loading and refrigerator temperature. The bolometers are made using standard microlithographic techniques suitable for fabrication of large scale arrays. Detailed measurements of optical response are presented for a range of bias conditions and are compared with theory. Measured noise spectra are shown and a model for the noise is presented. (C) 1999 American Institute of Physics. [S0003-6951(99)04206-0]. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Ctr Particle Astrophys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. RP Gildemeister, JM (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. EM jmg@physics.berkeley.edu NR 9 TC 57 Z9 57 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 8 PY 1999 VL 74 IS 6 BP 868 EP 870 DI 10.1063/1.123393 PG 3 WC Physics, Applied SC Physics GA 163RL UT WOS:000078419200032 ER PT J AU Creutz, C Fowler, JS AF Creutz, C Fowler, JS TI National labs research SO CHEMICAL & ENGINEERING NEWS LA English DT Letter C1 BNL, Dept Chem, Upton, NY USA. BNL, Pet Program, Upton, NY USA. RP Creutz, C (reprint author), BNL, Dept Chem, Upton, NY USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0009-2347 J9 CHEM ENG NEWS JI Chem. Eng. News PD FEB 8 PY 1999 VL 77 IS 6 BP 7 EP 7 PG 1 WC Chemistry, Multidisciplinary; Engineering, Chemical SC Chemistry; Engineering GA 175TZ UT WOS:000079112600002 ER PT J AU DeBeer, S Kiser, CN Mines, GA Richards, JH Gray, HB Solomon, EI Hedman, B Hodgson, KO AF DeBeer, S Kiser, CN Mines, GA Richards, JH Gray, HB Solomon, EI Hedman, B Hodgson, KO TI X-ray absorption spectra of the oxidized and reduced forms of C112D azurin from Pseudomonas aeruginosa SO INORGANIC CHEMISTRY LA English DT Article ID BLUE COPPER PROTEINS; ELECTRONIC-STRUCTURE CONTRIBUTIONS; FINE-STRUCTURE; SITE; PLASTOCYANIN; MUTANT; MUTAGENESIS; COMPLEXES; REDUCTION; LIGANDS AB The oxidized and reduced forms of a mutant of Pseudomonas aeruginosa azurin, in which the Cys112 has been replaced by an aspartate, have been studied by X-ray absorption spectroscopy. It is well established that the characteristic similar to 600 nm absorption feature of blue copper proteins is due to the S(Cys112) 3p pi --> Cu 3d(x)(-y)(2)(2) charge-transfer transition. While other mutagenesis studies have involved the creation of an artificial blue copper site, the present work involves a mutant in which the native blue copper site has been destroyed, thus serving as a direct probe of the importance of the copper-thiolate bond to the spectroscopy, active site structure, and electron-transfer function of azurin. Of particular interest is the dramatic decrease in electron-transfer rates, both electron self-exchange (k(ese) approximate to 10(5) M-1 s(-1) wild-type azurin vs k(ese) approximate to 20 M-1 s(-1) C112D azurin) and intramolecular electron transfer to ruthenium-labeled sites (k(et) approximate to 10(6) s(-1) wild-type azurin vs k(et) less than or equal to 10(3) s(-1) C112D azurin), which is observed in the mutant. These changes may be a reflection of significant differences in electronic coupling into the protein matrix (H-AB) and/or in the reorganization energy (lambda). These effects can be probed by the use of Cu K-edge X-ray absorption spectroscopy, the results of which indicate both a decrease in the covalency of the active site and an expansion of similar to 0.2 Angstrom in the Cu coordination sphere trigonal plane upon reduction of the C112D mutant. C1 Stanford Univ, Dept Chem, Stanford, CA 94305 USA. CALTECH, Beckman Inst, Pasadena, CA 91125 USA. Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Gray, HB (reprint author), CALTECH, Beckman Inst, Pasadena, CA 91125 USA. RI DeBeer, Serena/G-6718-2012 NR 35 TC 24 Z9 24 U1 0 U2 9 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 FEB 8 PY 1999 VL 38 IS 3 BP 433 EP 438 DI 10.1021/ic9804622 PG 6 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 167DE UT WOS:000078616700006 ER PT J AU de Rege, FM Kassebaum, JD Scott, BL Abney, KD Balaich, GJ AF de Rege, FM Kassebaum, JD Scott, BL Abney, KD Balaich, GJ TI Synthesis, structure, and reactivity of 1,2-(1 ',1 ',2 ',2 '-tetramethyldisilane-1 ',2 ')carborane SO INORGANIC CHEMISTRY LA English DT Article ID CARBON UNSATURATED-COMPOUNDS; 2-ATOM INSERTION REACTIONS; POLYSILANE HIGH POLYMERS; SI; HEXAMETHYLSILIRANE; POLYMERIZATION; ACETYLENES; CONVERSION; METATHESIS; CHEMISTRY AB The novel strained compound 1,2-(1',1',2',2'-tetramethyldisilane-1',2')carborane (1) was synthesized by the reaction of 1,2-dilithiocarborane and dichlorotetramethyldisilane. Compound 1 was characterized by solution methods and its structure determined by single-crystal X-ray diffraction. In contrast to its organic analogue o-(disilanyl)-phenylene, the reaction of 1 with ethanol leads to cleavage of a Si-C bond rather than a Si-Si bend. Similarly to other cyclic disilanes, exposure of a solution of I to oxygen leads to the insertion of an oxygen atom into the Si-Si bond. The structure of the oxygen inserted product was also determined by X-ray crystallography. The general chemistry and attempts at polymerizing 1 are briefly discussed. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. USAF Acad, Dept Chem, Chem Res Ctr, Colorado Springs, CO 80840 USA. RP de Rege, FM (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, CST-11,Mail Stop J514, Los Alamos, NM 87545 USA. RI Scott, Brian/D-8995-2017; OI Scott, Brian/0000-0003-0468-5396; de Rege, Francis/0000-0003-0013-5856 NR 37 TC 11 Z9 11 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD FEB 8 PY 1999 VL 38 IS 3 BP 486 EP 489 DI 10.1021/ic980992y PG 4 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 167DE UT WOS:000078616700014 ER PT J AU Yang, MN Fleming, GR AF Yang, MN Fleming, GR TI Two-color three-pulse photon echoes as a probe of electronic coupling in molecular complexes SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID PHOTOSYNTHETIC REACTION CENTERS; POLAR SOLVATION DYNAMICS; ENERGY-TRANSFER; RHODOBACTER-SPHAEROIDES; DEPENDENCE; TEMPERATURE; WAVELENGTH; DISTANCE; LIQUIDS; SPECTRA AB A two-color photon echo peak shift measurement to probe the electronic coupling strength in molecular complexes is proposed. Exciton transfer between the electronic eigenstates is neglected and the baths associated with each monomer are assumed to be independent of each other. Within this simplified model, we derive a useful relation which can be used to estimate the electronic coupling strength via a combination of a normal one-color and the present two-color peak shift measurements. A simulation based on the cumulant expansion technique illustrates the validity of our suggestion. (C) 1999 American Institute of Physics. [S0021-9606(99)00406-7]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA. RP Yang, MN (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. EM Fleming@cchem.berkeley.edu OI Yang, Mino/0000-0001-9504-0280 NR 45 TC 49 Z9 51 U1 0 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 8 PY 1999 VL 110 IS 6 BP 2983 EP 2990 DI 10.1063/1.477893 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 163AJ UT WOS:000078379800029 ER PT J AU Rodriguez, JA Jirsak, T Chaturvedi, S AF Rodriguez, JA Jirsak, T Chaturvedi, S TI Reaction of S-2 and SO2 with Pd/Rh(111) surfaces: Effects of metal-metal bonding on sulfur poisoning SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ELECTRONIC-STRUCTURE; BIMETALLIC SURFACES; CHEMICAL-PROPERTIES; CATALYTIC ACTIVITY; PD(111) SURFACE; NITRIC-OXIDE; ADSORPTION; PD; PHOTOEMISSION; CHEMISORPTION AB The surface chemistry of S-2 and SO2 on Rh(111), Pd/Rh(111) and polycrystalline Pd has been investigated using synchrotron-based high-resolution photoemission and ab initio self-consistent-field calculations. Pd adatoms lead to an increase in the rate of adsorption of S-2 on Rh(111), but they are less reactive than atoms of pure metallic palladium: Rh(111) S-a + 2O(a)) or transforms into SO3/SO4 species. The molecular SOx species disappear upon annealing to 450 K and only atomic S and O remain on the surfaces. A Pd monolayer supported on Rh(111) is not very active for the dissociation of SO2. In this respect, the Pd-1.0/Rh(111) system is less chemically active than pure Pd or Rh(111). The electronic perturbations associated with the Pd-Rh bonds reduce the electron donor ability of Pd, weakening the interactions between the Pd 4d orbitals and the lowest unoccupied molecular orbitals of S-2 and SO2. The behavior of the S-2/Pd/Rh(111) and SO2/Pd/Rh(111) systems shows that bimetallic bonding can reduce the reactivity of Pd towards sulfur-containing molecules. A very large drop in reactivity can be expected when Pd is bonded to s,p or early transition metals. (C) 1999 American Institute of Physics. [S0021-9606(99)70906-2]. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Rodriguez, JA (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. EM rodrigez@bnl.gov NR 70 TC 32 Z9 32 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 8 PY 1999 VL 110 IS 6 BP 3138 EP 3147 DI 10.1063/1.477910 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 163AJ UT WOS:000078379800047 ER PT J AU Ahmad, I Back, BB Chasman, RR Greene, JP Ishii, T Morss, LR Berg, GPA Bacher, AD Foster, CC Lozowski, WR Schmitt, W Stephenson, EJ Yamanaka, T AF Ahmad, I Back, BB Chasman, RR Greene, JP Ishii, T Morss, LR Berg, GPA Bacher, AD Foster, CC Lozowski, WR Schmitt, W Stephenson, EJ Yamanaka, T TI Possible observation of the 1/2(+)[880] orbital in Cm-249(96) SO NUCLEAR PHYSICS A LA English DT Article DE Cm-248(alpha,He-3); Th-232(alpha,He-3); Pb-208(alpha,He-3); E = 98.5 MeV; measured sigma(theta); Cm-249 deduced levels, j,pi ID SINGLE-PARTICLE STATES AB The position of the k(17/2) Shell orbital plays a significant role in determining the shell correction energy and hence the stability of the superheavy elements. A deformed component of this orbital, 1/2(+) [880], comes down in energy with increasing prolate deformation, and is expected to have an excitation energy of less than 2 MeV in nuclei with N = 153. We have performed the reaction Cm-248(He-4,He-3) using 98.5-MeV alpha particles from the IUCF cyclotron to populate high-e states in Cm-249. This reaction preferentially excites high-e states because of the angular momentum mismatch. The emerging He-3 ions were momentum analyzed with the K600 magnetic spectrometer, Spectra were measured at theta(cm) = 4.1 degrees, 6.1 degrees, 10.2 degrees, 12.2 degrees, and 16.2 degrees. The spectrometer was calibrated with the Pb-208(He-4,He-3) and( 232)Th(He-4,He-3) reactions at the same incident energy. Three strong peaks were identified in the Cm-248(He-4,He-3) spectrum and these have been given tentative assignments: 593 keV, 15/2 11/2(-)[725]; 1560 keV and 1898 keV, 17/2 1/2(+)[880], 15/2 13/2(-) [716]. Our data do not distinguish between the 17/2(+) and 15/2(-) assignments. (C) 1999 Published by Elsevier Science B.V. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Indiana Univ, Cyclotron Facil, Bloomington, IN 47408 USA. JAERI, Ibaraki, Osaka, Japan. RP Ahmad, I (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 16 TC 6 Z9 6 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 FEB 8 PY 1999 VL 646 IS 2 BP 175 EP 186 DI 10.1016/S0375-9474(98)00618-6 PG 12 WC Physics, Nuclear SC Physics GA 166JB UT WOS:000078571500003 ER PT J AU Hori, K AF Hori, K TI Branes and electric-magnetic duality in supersymmetric QCD SO NUCLEAR PHYSICS B LA English DT Article ID GAUGE-THEORIES; BREAKING; ORIENTIFOLDS; DYNAMICS AB We study the type IIA limit of the M-theory fivebrane configuration corresponding to N = 1 supersymmetric QCD with massless quarks, We identify the effective gauge coupling constant that fits with the Novikov-Shifman-Veinshtein-Zakharov exact beta function, We find two different type IIA limits that correspond to the electric and magnetic descriptions of SQCD, as observed in the massive case by Schmaltz and Sundrum. The analysis is extended to the case of symplectic and orthogonal gauge groups. In any of the cases considered in this paper, the electric and magnetic configurations are smoothly interpolated via M-theory. This is in sharp contrast with the proposed derivation of N = 1 duality within the weakly coupled type IIA string theory where a singularity is inevitable unless one turns on a parameter that takes the theory away from an interesting point. (C) 1999 Elsevier Science B.V. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Dept Phys, 366 Le Conte Hall, Berkeley, CA 94720 USA. NR 35 TC 10 Z9 10 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 FEB 8 PY 1999 VL 540 IS 1-2 BP 187 EP 229 DI 10.1016/S0550-3213(98)00675-0 PG 43 WC Physics, Particles & Fields SC Physics GA 166GR UT WOS:000078568300006 ER PT J AU Aniol, KA Armstrong, DS Baylac, M Burtin, E Calarco, J Cates, GD Cavata, C Chen, JP Chudakov, E Dale, D de Jager, CW Deur, A Djawotho, P Epstein, MB Escoffier, S Ewell, L Falletto, N Finn, JM Fissum, K Fleck, A Frois, B Gao, J Garibaldi, F Gasparian, A Gerstner, GM Gilman, R Glamazdin, A Gomez, J Gorbenko, V Hansen, O Hersman, F Holmes, R Holtrop, M Humensky, B Incerti, S Jardillier, J Jones, MK Jorda, J Jutier, C Kahl, W Kim, DH Kim, MS Kramer, K Kumar, KS Kuss, M LeRose, J Leuschner, M Lhuillier, D Liyanage, N Lourie, R Madey, R Margaziotis, DJ Marie, F Martino, J Mastromarino, P McCormick, K McIntyre, J Meziani, ZE Michaels, R Miller, GW Neyret, D Perdrisat, C Petratos, GG Pomatsalyuk, R Price, JS Prout, D Punjabi, V Pussieux, T Quemener, G Rutledge, G Rutt, PM Saha, A Souder, PA Spradlin, M Suleiman, R Thompson, J Todor, L Ulmer, PE Vlahovic, B Wijesooriya, K Wilson, R Wojtsekhowski, B AF Aniol, KA Armstrong, DS Baylac, M Burtin, E Calarco, J Cates, GD Cavata, C Chen, JP Chudakov, E Dale, D de Jager, CW Deur, A Djawotho, P Epstein, MB Escoffier, S Ewell, L Falletto, N Finn, JM Fissum, K Fleck, A Frois, B Gao, J Garibaldi, F Gasparian, A Gerstner, GM Gilman, R Glamazdin, A Gomez, J Gorbenko, V Hansen, O Hersman, F Holmes, R Holtrop, M Humensky, B Incerti, S Jardillier, J Jones, MK Jorda, J Jutier, C Kahl, W Kim, DH Kim, MS Kramer, K Kumar, KS Kuss, M LeRose, J Leuschner, M Lhuillier, D Liyanage, N Lourie, R Madey, R Margaziotis, DJ Marie, F Martino, J Mastromarino, P McCormick, K McIntyre, J Meziani, ZE Michaels, R Miller, GW Neyret, D Perdrisat, C Petratos, GG Pomatsalyuk, R Price, JS Prout, D Punjabi, V Pussieux, T Quemener, G Rutledge, G Rutt, PM Saha, A Souder, PA Spradlin, M Suleiman, R Thompson, J Todor, L Ulmer, PE Vlahovic, B Wijesooriya, K Wilson, R Wojtsekhowski, B CA HAPPEX Collaborat TI Measurement of the neutral weak form factors of the proton SO PHYSICAL REVIEW LETTERS LA English DT Article ID MAGNETIC-MOMENT; POLARIZED ELECTRONS; STRANGENESS RADIUS; MATRIX-ELEMENTS; SCATTERING; NUCLEON; LOOPS; MODEL AB We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from the proton. The kinematic point [[theta(1ab)] = 12.3 degrees and [Q(2)] = 0.48 (GeV/c)(2)] is chosen to provide sensitivity, at a level that is of theoretical interest, to the strange electric form factor G(E)(s). The result, A = -14.5 +/- 2.2 ppm, is consistent with the electroweak standard model and no additional contributions from strange quarks. In particular, the measurement implies G(E)(s) + 0.39G(M)(s) = 0.023 +/- 0.034(stat) +/- 0.022(syst) +/- 0.026(delta G(E)(n)), where the last uncertainty arises from the estimated uncertainty in the neutron electric form factor. [S0031-9007(98)08312-4]. C1 Calif State Univ Los Angeles, Los Angeles, CA 90032 USA. Univ Blaise Pascal, IN2P3, LPC, F-63177 Clermont Ferrand, France. Hampton Univ, Hampton, VA 23668 USA. Harvard Univ, Cambridge, MA 02138 USA. Ist Nazl Fis Nucl, Sez Sanita, I-00161 Rome, Italy. Thomas Jefferson Natl Accelerator Lab, Newport News, VA 23606 USA. Kent State Univ, Kent, OH 44242 USA. Univ Kentucky, Lexington, KY 40506 USA. Kharkov Phys & Technol Inst, UA-310108 Kharkov, Ukraine. Kyungpook Natl Univ, Taegu 702701, South Korea. Univ Maryland, College Pk, MD 20742 USA. MIT, Cambridge, MA 02139 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 23508 USA. Princeton Univ, Princeton, NJ 08544 USA. Univ Regina, Regina, SK S4S 0A2, Canada. Rutgers State Univ, Piscataway, NJ 08855 USA. CEA Saclay, DAPNIA, SPhN, 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. Coll William & Mary, Williamsburg, VA 23187 USA. RP Aniol, KA (reprint author), Calif State Univ Los Angeles, Los Angeles, CA 90032 USA. RI Kuss, Michael/H-8959-2012; McIntyre, Justin/P-1346-2014; CAVATA, Christian/P-6496-2015 OI Jorda, Jean-Paul/0000-0003-0216-591X; Glamazdin, Alexander/0000-0002-4172-7324; Incerti, Sebastien/0000-0002-0619-2053; McIntyre, Justin/0000-0002-3706-4310; NR 18 TC 146 Z9 149 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 FEB 8 PY 1999 VL 82 IS 6 BP 1096 EP 1100 DI 10.1103/PhysRevLett.82.1096 PG 5 WC Physics, Multidisciplinary SC Physics GA 164HV UT WOS:000078458500005 ER PT J AU Shaw, RW Young, JP Cooper, SP Webb, OF AF Shaw, RW Young, JP Cooper, SP Webb, OF TI Spontaneous ultraviolet emission from (233)uranium/(229)thorium samples SO PHYSICAL REVIEW LETTERS LA English DT Article ID TH-229; ISOMER; STATE AB The spontaneous ultraviolet luminescence reported [G. M. Irwin and K. H. Kim, Phys. Rev. Lett. 79, 990 (1997); D.S. Richardson et al., ibid. 80, 3206 (1998)] from (233)uranium compounds and ascribed to an ultraviolet gamma-ray emission from the metastable (229)thorium daughter is actually N-2 discharge emission induced in the air surrounding the sample by the sample radioactivity. The UV spectrum from high elemental and isotopic purity (UO3)-U-233 reported here also exhibits a line at 391.3 nm that does not appear to be due to electric discharge N-2 emission. [S0031-9007(99)08412-4]. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. RP Shaw, RW (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. NR 9 TC 45 Z9 47 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 FEB 8 PY 1999 VL 82 IS 6 BP 1109 EP 1111 DI 10.1103/PhysRevLett.82.1109 PG 3 WC Physics, Multidisciplinary SC Physics GA 164HV UT WOS:000078458500008 ER PT J AU Thomas, TD Berrah, N Bozek, J Carroll, TX Hahne, J Karlsen, T Kukk, E Saethre, LJ AF Thomas, TD Berrah, N Bozek, J Carroll, TX Hahne, J Karlsen, T Kukk, E Saethre, LJ TI Photon energy dependence of the 1 sigma(u)/1 sigma(g) intensity ratio in carbon 1s photoelectron spectroscopy of ethyne SO PHYSICAL REVIEW LETTERS LA English DT Article ID INTRAMOLECULAR BOND LENGTHS; SHELL SHAPE RESONANCES; ELECTRON-IMPACT; SPECTRA; C2H2; EXCITATION; MOLECULES; STATES AB High-resolution measurements of the C Is photoelectron spectrum of ethyne (acetylene) at phc,ton energies between 297 and 348 eV have been analyzed to give the energy dependence of the relative cross sections for ionization of the 1 sigma(g), and 1 sigma(u) orbitals. The 1 sigma(u)(-1)/1 sigma(g)(-1) intensity ratio is greater than 1 at the lowest photon energies but reaches a minimum of about 0.6 between 315 and 320 eV. These results can be understood in terms of the effect of shape resonance on the ionization cross section and provide quantitative information on the position and magnitude of such resonances. [S0031-9007(98)08336-7]. C1 Oregon State Univ, Dept Chem, Corvallis, OR 97331 USA. Western Michigan Univ, Dept Phys, Kalamazoo, MI 49008 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Keuka Coll, New York, NY 14478 USA. Univ Bergen, Dept Chem, N-5007 Bergen, Norway. RP Thomas, TD (reprint author), Oregon State Univ, Dept Chem, Gilbert Hall 153, Corvallis, OR 97331 USA. RI Bozek, John/E-4689-2010; Bozek, John/E-9260-2010 OI Bozek, John/0000-0001-7486-7238 NR 16 TC 53 Z9 53 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 FEB 8 PY 1999 VL 82 IS 6 BP 1120 EP 1123 DI 10.1103/PhysRevLett.82.1120 PG 4 WC Physics, Multidisciplinary SC Physics GA 164HV UT WOS:000078458500011 ER PT J AU Ackerstaff, K Airapetian, A Akopov, N Amarian, M Aschenauer, EC Avakian, H Avetissian, A Bains, B Baumgarten, C Beckmann, M Belostotski, S Belz, JE Benisch, T Bernreuther, S Bianchi, N Blouw, J Bottcher, H Borissov, A Brack, J Brauksiepe, S Braun, B Bray, B Brons, S Bruckner, W Brull, A Bruins, EEW Bulten, JH Cadman, RV Capitani, GP Carter, P Chumney, P Cisbani, E Court, GR Dalpiaz, PF De Sanctis, E De Schepper, D Devitsin, E Huberts, PKAD Di Nezza, P Duren, M Dvoredsky, A Elbakian, G Fantoni, A Fechtchenko, A Ferstl, M Fick, D Fiedler, K Filippone, BW Fischer, H Fox, B Franz, J Frabetti, S Frullani, S Funk, MA Gagunashvili, ND Gao, H Garber, Y Garibaldi, F Gavrilov, G Geiger, P Gharibyan, V Giordjian, V Golendukhin, A Graw, G Grebeniouk, O Green, PW Greeniaus, LG Grosshauser, C Gute, A Haeberli, W Hansen, JO Hasch, D Hausser, O Henderson, R Henkes, T Henoch, M Hertenberger, R Holler, Y Holt, RJ Hoprich, W Ihssen, H Iodice, M Izotov, A Jackson, HE Jgoun, A Kaiser, R Kinney, E Kisselev, A Kitching, P Kobayashi, H Koch, N Konigsmann, K Kolstein, M Kolster, H Korotkov, V Korsch, W Kozlov, V Kramer, LH Krivokhijine, VG Masoli, F Mateos, A McAndrew, M McIlhany, K McKeown, RD Meissner, F Metz, A Meyners, N Mikloukho, O Miller, CA Miller, MA Milner, R Mitsyn, V Most, A Mozzetti, R Muccifora, V Nagaitsev, A Naryshkin, Y Nathan, AM Neunreither, F Niczyporuk, M Nowak, WD Nupieri, M Ogami, H O'Neill, TG Owen, BR Papavassiliou, V Pate, SF Pitt, M Potashov, S Potterveld, DH Rakness, G Reali, A Redwine, R Reolon, AR Ristinen, R Rith, K Roloff, H Rossi, P Rudnitsky, S Ruh, M Ryckbosch, D Sakemi, Y Savin, I Schmidt, F Schmitt, H Schnell, G Schuler, KP Schwind, A Shibata, TA Shin, T Shutov, V Simani, C Simon, A Sinram, K Slavich, P Sowinski, J Spengos, M Steffens, E Stenger, J Stewart, J Stock, F Stoesslein, U Sutter, M Tallini, H Taroian, S Terkulov, A Tipton, B Tytgat, M Urciuoli, GM van Hunen, JJ van de Vyver, R van den Brand, JFJ van der Steenhoven, G Vetterli, MC Vincter, M Volk, E Wander, W Williamson, SE Wise, T Woller, K Yoneyama, S Zapfe-Duren, K Zohrabian, H AF Ackerstaff, K Airapetian, A Akopov, N Amarian, M Aschenauer, EC Avakian, H Avetissian, A Bains, B Baumgarten, C Beckmann, M Belostotski, S Belz, JE Benisch, T Bernreuther, S Bianchi, N Blouw, J Bottcher, H Borissov, A Brack, J Brauksiepe, S Braun, B Bray, B Brons, S Bruckner, W Brull, A Bruins, EEW Bulten, JH Cadman, RV Capitani, GP Carter, P Chumney, P Cisbani, E Court, GR Dalpiaz, PF De Sanctis, E De Schepper, D Devitsin, E Huberts, PKAD Di Nezza, P Duren, M Dvoredsky, A Elbakian, G Fantoni, A Fechtchenko, A Ferstl, M Fick, D Fiedler, K Filippone, BW Fischer, H Fox, B Franz, J Frabetti, S Frullani, S Funk, MA Gagunashvili, ND Gao, H Garber, Y Garibaldi, F Gavrilov, G Geiger, P Gharibyan, V Giordjian, V Golendukhin, A Graw, G Grebeniouk, O Green, PW Greeniaus, LG Grosshauser, C Gute, A Haeberli, W Hansen, JO Hasch, D Hausser, O Henderson, R Henkes, T Henoch, M Hertenberger, R Holler, Y Holt, RJ Hoprich, W Ihssen, H Iodice, M Izotov, A Jackson, HE Jgoun, A Kaiser, R Kinney, E Kisselev, A Kitching, P Kobayashi, H Koch, N Konigsmann, K Kolstein, M Kolster, H Korotkov, V Korsch, W Kozlov, V Kramer, LH Krivokhijine, VG Masoli, F Mateos, A McAndrew, M McIlhany, K McKeown, RD Meissner, F Metz, A Meyners, N Mikloukho, O Miller, CA Miller, MA Milner, R Mitsyn, V Most, A Mozzetti, R Muccifora, V Nagaitsev, A Naryshkin, Y Nathan, AM Neunreither, F Niczyporuk, M Nowak, WD Nupieri, M Ogami, H O'Neill, TG Owen, BR Papavassiliou, V Pate, SF Pitt, M Potashov, S Potterveld, DH Rakness, G Reali, A Redwine, R Reolon, AR Ristinen, R Rith, K Roloff, H Rossi, P Rudnitsky, S Ruh, M Ryckbosch, D Sakemi, Y Savin, I Schmidt, F Schmitt, H Schnell, G Schuler, KP Schwind, A Shibata, TA Shin, T Shutov, V Simani, C Simon, A Sinram, K Slavich, P Sowinski, J Spengos, M Steffens, E Stenger, J Stewart, J Stock, F Stoesslein, U Sutter, M Tallini, H Taroian, S Terkulov, A Tipton, B Tytgat, M Urciuoli, GM van Hunen, JJ van de Vyver, R van den Brand, JFJ van der Steenhoven, G Vetterli, MC Vincter, M Volk, E Wander, W Williamson, SE Wise, T Woller, K Yoneyama, S Zapfe-Duren, K Zohrabian, H CA HERMES Collaborat TI Beam-induced nuclear depolarization in a gaseous polarized-hydrogen target SO PHYSICAL REVIEW LETTERS LA English DT Article AB Spin-polarized atomic hydrogen is used as a gaseous polarized-proton target in high-energy and nuclear-physics experiments operating with internal beams in storage rings. When such beams are intense and bunched, this type of target can be depolarized by a resonant interaction with the transient magnetic field generated by the beam bunches. This effect has been studied with the HERA positron beam in the HERMES experiment at DESY. Resonances have been observed and a simple analytic model has been used to explain their shape and position. Operating conditions for the experiment have been found where there is no significant target depolarization due to this effect. [S0031-9007(98)08340-9]. C1 Univ Alberta, Dept Phys, Edmonton, AB T6G 2N2, Canada. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. CALTECH, WK Kellog Radiat Lab, Pasadena, CA 91125 USA. Univ Colorado, Nucl Phys Lab, Boulder, CO 80309 USA. DESY, Deutsch Elektronen Synchrotron, D-22603 Hamburg, Germany. DESY, D-15738 Zeuthen, Germany. Joint Inst Nucl Res, Dubna 141980, Russia. Univ Erlangen Nurnberg, Inst Phys, D-91058 Erlangen, Germany. Univ Ferrara, Dipartimento Fis, I-44100 Ferrara, Italy. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Florida Int Univ, Dept Phys, Miami, FL 33199 USA. State Univ Ghent, Dept Subatom & Radiat Phys, D-79104 Freiburg, Germany. Max Planck Inst Kernphys, D-69029 Heidelberg, Germany. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. Univ Liverpool, Dept Phys, Liverpool L69 7ZE, Merseyside, England. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Univ Marburg, Inst Phys, D-35037 Marburg, Germany. MIT, Nucl Sci Lab, Cambridge, MA 02139 USA. Univ Michigan, Randall Lab Phys, Ann Arbor, MI 48109 USA. PN Lebedev Phys Inst, Moscow 117924, Russia. Univ Munich, Sekt Phys, D-85748 Garching, Germany. New Mexico State Univ, Dept Phys, Las Cruces, NM 88003 USA. Natl Inst Kernfys Hoge Energiefys, NIKHEF, NL-1009 DB Amsterdam, Netherlands. Petersburg Nucl Phys Inst, St Petersburg 188350, Russia. Ist Nazl Fis Nucl, Sez Sanita, I-00161 Rome, Italy. Simon Fraser Univ, Dept Phys, Burnaby, BC V5A 1S6, Canada. TRIUMF, Vancouver, BC V6T 2A3, Canada. Tokyo Inst Technol, Tokyo 152, Japan. Free Univ Amsterdam, Dept Phys & Astron, NL-1081 HV Amsterdam, Netherlands. Yerevan Phys Inst, Yerevan 375036, Armenia. RP Ackerstaff, K (reprint author), Univ Alberta, Dept Phys, Edmonton, AB T6G 2N2, Canada. RI Gao, Haiyan/G-2589-2011; Gavrilov, Gennady/C-6260-2013; Holt, Roy/E-5803-2011; Kozlov, Valentin/M-8000-2015; Terkulov, Adel/M-8581-2015; Cisbani, Evaristo/C-9249-2011 OI Cisbani, Evaristo/0000-0002-6774-8473 NR 9 TC 17 Z9 17 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 FEB 8 PY 1999 VL 82 IS 6 BP 1164 EP 1168 DI 10.1103/PhysRevLett.82.1164 PG 5 WC Physics, Multidisciplinary SC Physics GA 164HV UT WOS:000078458500022 ER PT J AU Schroeder, CB Whittum, DH Wurtele, JS AF Schroeder, CB Whittum, DH Wurtele, JS TI Multimode analysis of the hollow plasma channel wakefield accelerator SO PHYSICAL REVIEW LETTERS LA English DT Article ID BEAM BREAKUP INSTABILITIES; INTENSITY LASER-PULSES; LINEAR ACCELERATORS AB The hollow plasma channel is analyzed as an accelerating structure. The excitation of the channel by an ultrarelativistic beam is analyzed. Coupling to the fundamental and all higher-order azimuthal modes of the excited electromagnetic fields is derived. Implications of this work for plasma-based accelerators, including beam loading and beam breakup, are discussed. Small initial transverse displacements of the beam are shown to couple to deflecting modes in the channel. The asymptotic growth rate of the resultant beam breakup instability is analyzed and a method for reducing the growth is proposed. [S0031-9007(99)08413-6]. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Lawrence Berkeley Natl Lab, Ctr Beam Phys, Berkeley, CA 94720 USA. RP Schroeder, CB (reprint author), Univ Calif Berkeley, Dept 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 20 TC 23 Z9 23 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 FEB 8 PY 1999 VL 82 IS 6 BP 1177 EP 1180 DI 10.1103/PhysRevLett.82.1177 PG 4 WC Physics, Multidisciplinary SC Physics GA 164HV UT WOS:000078458500025 ER PT J AU Burns, AR Houston, JE Carpick, RW Michalske, TA AF Burns, AR Houston, JE Carpick, RW Michalske, TA TI Friction and molecular deformation in the tensile regime SO PHYSICAL REVIEW LETTERS LA English DT Article ID FIELD OPTICAL MICROSCOPES; FORCE MICROSCOPY; ORGANIC-SURFACES; DISTANCE CONTROL; ATOMIC-SCALE; SHEAR-FORCE; ADHESION; FILMS; PROBE; TIP AB Recent molecular level studies of energy dissipation in sliding friction have suggested a contribution from adhesive forces. In order to observe this directly, we have constructed a scanning force microscope with decoupled lateral and normal force sensors to simultaneously observe the onset of both friction and attractive forces. Measurements made on self-assembling alkanethiol films with chemically different tail groups show that friction can increase with stronger adhesive intermolecular forces and from the associated tensile deformation and collective motion of the thiol chains. [S0031-9007(99)08383-0]. C1 Sandia Natl Labs, Surface & Interface Sci Dept, Albuquerque, NM 87185 USA. RP Burns, AR (reprint author), Sandia Natl Labs, Surface & Interface Sci Dept, MS 1413, Albuquerque, NM 87185 USA. NR 22 TC 56 Z9 56 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 FEB 8 PY 1999 VL 82 IS 6 BP 1181 EP 1184 DI 10.1103/PhysRevLett.82.1181 PG 4 WC Physics, Multidisciplinary SC Physics GA 164HV UT WOS:000078458500026 ER PT J AU Henson, BF Asay, BW Sander, RK Son, SF Robinson, JM Dickson, PM AF Henson, BF Asay, BW Sander, RK Son, SF Robinson, JM Dickson, PM TI Dynamic measurement of the HMX beta-delta phase transition by second harmonic generation SO PHYSICAL REVIEW LETTERS LA English DT Article AB We demonstrate the use of optical second harmonic generation (SHG) to identify the beta-delta phase transition in polycrystalline HMX. This phase transition has been implicated in the thermal decomposition of HMX for over 30 years. We measure an order of magnitude difference in SHG cross section from the beta and delta phases and use this intensity difference to observe the phase transition during CO2 laser irradiation. This is the first known ill situ measurement of a phase transition in such an energetic material during a dynamic experiment, and the first example of SHG from this class of organic nitramine molecular crystals. [S0031-9007(98)08215-5]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Henson, BF (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 17 TC 58 Z9 61 U1 0 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 FEB 8 PY 1999 VL 82 IS 6 BP 1213 EP 1216 DI 10.1103/PhysRevLett.82.1213 PG 4 WC Physics, Multidisciplinary SC Physics GA 164HV UT WOS:000078458500034 ER PT J AU Shan, W Walukiewicz, W Ager, JW Haller, EE Geisz, JF Friedman, DJ Olson, JM Kurtz, SR AF Shan, W Walukiewicz, W Ager, JW Haller, EE Geisz, JF Friedman, DJ Olson, JM Kurtz, SR TI Band anticrossing in GaInNAs alloys SO PHYSICAL REVIEW LETTERS LA English DT Article ID NITROGEN; GAP; SEMICONDUCTORS; LUMINESCENCE; GAAS1-XNX AB We present evidence for a strong interaction between the conduction band and a narrow resonant band formed by nitrogen states in Ga1-xInxNyAs1-y alloys. The interaction leads to a splitting of the conduction band into two subbands and a reduction of the fundamental band gap. An anticrossing of the extended states of the conduction band of the Ga1-xInxAs matrix and the localized nitrogen resonant states is used to model the interaction. Optical transitions associated with the energy minima of the two subbands and the characteristic anticrossing behavior of the transitions under applied hydrostatic pressure have been unambiguously observed using photomodulation spectroscopy. The experimental results are in excellent quantitative agreement with the model. [S0031-9007(98)08364-1]. 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. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Shan, W (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. OI Ager, Joel/0000-0001-9334-9751 NR 20 TC 1280 Z9 1303 U1 4 U2 91 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 FEB 8 PY 1999 VL 82 IS 6 BP 1221 EP 1224 DI 10.1103/PhysRevLett.82.1221 PG 4 WC Physics, Multidisciplinary SC Physics GA 164HV UT WOS:000078458500036 ER PT J AU Lopez, D Kwok, WK Safar, H Olsson, RJ Petrean, AM Paulius, L Crabtree, GW AF Lopez, D Kwok, WK Safar, H Olsson, RJ Petrean, AM Paulius, L Crabtree, GW TI Spatially resolved dynamic correlation in the vortex state of high temperature superconductors SO PHYSICAL REVIEW LETTERS LA English DT Article ID LATTICE-MELTING TRANSITION; SINGLE-CRYSTAL YBA2CU3O7; LIQUIDS AB We report transport measurements in the mixed state of YBa2Cu3O7-delta single crystals using a contact geometry which enables control of the gradient of the Lorentz force acting on the vortices. The spatial dependence of the vortex velocity profile in the liquid and solid vortex phases is resolved providing information about the transverse dynamic correlation of vortices. While in the liquid phase the vortices respond locally to the driving force, in the solid regime they show long range velocity correlation over macroscopic distances. At high driving force gradients, vortex-vortex shear stresses exceed the elastic limit and the dynamics is characterized by plastic motion. [S0031-9007(98)08260-X]. C1 Argonne Natl Lab, Div Sci Mat, Argonne, IL 60435 USA. Univ Illinois, Chicago, IL 60607 USA. Western Michigan Univ, Kalamazoo, MI 49008 USA. RP Lopez, D (reprint author), Argonne Natl Lab, Div Sci Mat, Argonne, IL 60435 USA. NR 18 TC 76 Z9 76 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 8 PY 1999 VL 82 IS 6 BP 1277 EP 1280 DI 10.1103/PhysRevLett.82.1277 PG 4 WC Physics, Multidisciplinary SC Physics GA 164HV UT WOS:000078458500050 ER PT J AU Bushaw, BA Nortershauser, W Wendt, K AF Bushaw, BA Nortershauser, W Wendt, K TI Lineshapes and optical selectivity in high-resolution double-resonance ionization mass spectrometry SO SPECTROCHIMICA ACTA PART B-ATOMIC SPECTROSCOPY LA English DT Article ID DIODE-LASER; CA-41; CALCIUM; SPECTROSCOPY; RESORPTION; GENERATION; BONE AB Lineshapes expected in high-resolution double-resonance ionization spectroscopy are calculated using the density matrix formalism, integrated over experimentally realistic conditions including atomic velocity and angular distributions as well as laser intensity profiles. The results of these calculations are compared with experimental measurements on the system 4s(2) S-1(0) --> 4s4p P-1(1) --> 4s4d D-1(1) --> ion for calcium. The measurements of lineshape, with a dynamic range of > 10(6), reveal and confirm subtle effects predicted by theory. These include the shape, position and intensity of the laser-induced structure in the spectra and the simultaneous presence of coherent and incoherent excitation processes. The calculations are able to accurately predict isotopic selectivities achieved in experimental resonance ionization measurements and are used to evaluate these values for the detection of minor calcium isotopes, including the radionuclide Ca-41. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Pacific NW Lab, Richland, WA 99352 USA. Univ Mainz, Inst Phys, D-55099 Mainz, Germany. RP Bushaw, BA (reprint author), Pacific NW Lab, POB 999, Richland, WA 99352 USA. RI Wendt, Klaus/D-7306-2011; Nortershauser, Wilfried/A-6671-2013 OI Wendt, Klaus/0000-0002-9033-9336; Nortershauser, Wilfried/0000-0001-7432-3687 NR 27 TC 34 Z9 34 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0584-8547 J9 SPECTROCHIM ACTA B JI Spectroc. Acta Pt. B-Atom. Spectr. PD FEB 8 PY 1999 VL 54 IS 2 BP 321 EP 332 DI 10.1016/S0584-8547(98)00250-X PG 12 WC Spectroscopy SC Spectroscopy GA 183XU UT WOS:000079580300005 ER PT J AU Singh, S Sasaki, DY Cesarano, J Hurd, AJ AF Singh, S Sasaki, DY Cesarano, J Hurd, AJ TI Nanometer pores in ultrathin silica films prepared by self-assembly of organic spacers in an alkylsiloxane monolayer SO THIN SOLID FILMS LA English DT Article DE ultrathin silica film; alkylsiloxane monolayer; Langmuir-Blodgett film; organic spacer ID INORGANIC MEMBRANES; ALUMINA MEMBRANES; PATTERN TRANSFER; DEPOSITION; LAYERS AB Patterning of nanoscale pores in ultrathin silica films has been achieved via the self-organization of an organic spacer molecule in a monolayer of an alkyltrimethoxysilane. Langmuir-Blodgett films of monolayers of octadecyltrimethoxysilane (OTMS) doped with octadecylsulfonate sodium salt were deposited from a pure water subphase onto silicon substrates. The samples were heat treated at 80-101 degrees C yielding highly condensed, molecularly flat films with good surface coverage. Removal of the organics and spacer molecules via calcination of the monolayers at 450 degrees C for 8-10 h yielded thin (0.5-0.7 nm) silica films decorated with circular pores of uniform size, ranging from 0.8 to 400 nm dependent upon the ratio of spacer molecule to OTMS. Scanning force microscopy was used to image the nanoscale features generated in the films and also to provide some qualitative information on the mechanical properties of the films. The ability to create uniform pore sizes in metal oxide thin-films is attractive for selectively sorbent materials for sensors and separation membranes. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Sandia Natl Labs, Dept 147, Albuquerque, NM 87185 USA. RP Sasaki, DY (reprint author), Sandia Natl Labs, Dept 147, POB 5800, Albuquerque, NM 87185 USA. EM dysasak@sandia.gov NR 32 TC 11 Z9 11 U1 1 U2 5 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 FEB 8 PY 1999 VL 339 IS 1-2 BP 209 EP 215 DI 10.1016/S0040-6090(98)01404-7 PG 7 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 173YX UT WOS:000079008300035 ER PT J AU Kruzic, JJ Campbell, JP Ritchie, RO AF Kruzic, JJ Campbell, JP Ritchie, RO TI On the fatigue behavior of gamma-based titanium aluminides: Role of small cracks SO ACTA MATERIALIA LA English DT Article ID HIGH-CYCLE FATIGUE; GROWTH-BEHAVIOR; TIAL-ALLOY; PROPAGATION; FRACTURE AB Gamma-TiAl based alloys have recently received attention for potential elevated temperature applications in gas-turbine engines. However, although expected critical crack sizes for some targeted applications (e.g. gas-turbine engine blades) may be less than similar to 500 mu m, most fatigue-crack growth studies to date have focused on the behavior of large (on the order of a few millimeters) through-thickness cracks. Since successful implementation of damage-tolerant life-prediction methodologies requires that the fatigue properties be understood for crack sizes representative of those seen in service conditions, the present work is focused on characterizing the initiation and growth behavior of small (a similar to 25-300 mu m) fatigue cracks in a y-TiAl based alloy, of composition Ti-47Al-2Nb-2Cr-0.2B (at.%), with both duplex (average grain size of similar to 17 mu m) and refined lamellar (average colony size of similar to 145 mu m) microstructures. Results are compared to the behavior of large (a > 5 mm), through-thickness cracks from a previous study. Superior crack initiation resistance is observed in the duplex microstructure, with no cracks nucleating after up to 500 000 cycles at maximum stress levels (R = 0.1) in excess of the monotonic yield stress, sigma(y). Comparatively, in the lamellar microstructure cracks nucleated readily at applied maximum stresses below the yield stress (85% sigma(y)) after as few as 500 cycles. In terms of crack growth, measurements for small fatigue cracks in the duplex and lamellar microstructures showed that both microstructures have comparable intrinsic fatigue-crack growth resistance in the presence of small flaws. This observation contrasts previous comparisons of large-crack data, where the lamellar structure showed far superior fatigue-crack growth resistance than the duplex structure. Such "small-crack effects" are examined both in terms of similitude (i.e. crack tip shielding) and continuum (i.e. biased microstructural sampling) limitations of traditional linear elastic fracture mechanics. (C) Published by Elsevier Science Ltd on behalf of Acta Metallurgica Inc. 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. RP Ritchie, RO (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Ritchie, Robert/A-8066-2008; Kruzic, Jamie/M-3558-2014 OI Ritchie, Robert/0000-0002-0501-6998; Kruzic, Jamie/0000-0002-9695-1921 NR 34 TC 46 Z9 48 U1 1 U2 9 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 EI 1873-2453 J9 ACTA MATER JI Acta Mater. PD FEB 5 PY 1999 VL 47 IS 3 BP 801 EP 816 DI 10.1016/S1359-6454(98)00409-1 PG 16 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 170BQ UT WOS:000078785900008 ER PT J AU Kameda, J Bloomer, TE AF Kameda, J Bloomer, TE TI Kinetics of grain-boundary segregation and desegregation of sulfur and phosphorus during post-irradiation annealing SO ACTA MATERIALIA LA English DT Article ID PRESSURE-VESSEL STEELS; SOLUTE SEGREGATION; ALLOYS; EMBRITTLEMENT; EQUILIBRIUM; IRON; MODEL AB A study on dynamic impurity-defect interaction in Cu-doped, P-doped and Cu-P-doped ferritic alloys all containing residual S has been made in terms of the influence of post-irradiation annealing (PIA: at 573-958 K for 0.1-1000 h) on the intergranular S and P segregation and the microhardness. In a Cu-doped alloy, which shows no P segregation, PIA produced a greater rate and magnitude of S segregation than thermal annealing (TA). Grain-boundary P enrichment was achieved during an early stage of lower-temperature PIA but not during that of TA in P-containing alloys. A Cu-P-doped alloy showed a stronger effect of the PIA on the P segregation rate than a P-doped alloy. Intergranular P desegregation and S seg regation concurrently occurred at higher PIA temperatures. There was a tendency for the microhardness to increase with increasing amount of segregated P. The kinetics of the impurity segregation was analyzed using a modified McLean theory. Based on the estimated activation energies, it is shown that the S segregation in the post-irradiation-annealed Cu-doped alloy is controlled by vacancy-enhanced diffusion while the P segregation in P-containing alloys subjected to lower-temperature PIA proceeds via mobile P-interstitial complexes. By applying a Gaussian relaxation model, the P desegregation during prolonged PIA at higher temperatures was found to be assisted by the formation and migration of vacancies. (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Kameda, J (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 39 TC 13 Z9 19 U1 0 U2 1 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 FEB 5 PY 1999 VL 47 IS 3 BP 893 EP 903 DI 10.1016/S1359-6454(98)00397-8 PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 170BQ UT WOS:000078785900017 ER PT J AU Gutowski, M Skurski, P AF Gutowski, M Skurski, P TI Electron binding energies in linear dipole-bound (HCN)(n)(-) (n=2-5) anions SO CHEMICAL PHYSICS LETTERS LA English DT Article ID PHOTOELECTRON-SPECTROSCOPY; GROUND-STATE; CLUSTERS; DYNAMICS; (HF)(2)(-); SPECTRA; DIMER AB The (HCN)(2)(-) anion has been studied at the coupled cluster level of theory with single, double, and non-iterative triple excitations whereas equilibrium structures and electron binding energies for larger linear (HCN)(n)(-) (n = 3-5) clusters have been determined at the second-order Moller-Plesset (MP2) level. The adiabatic electron affinity of (HCN)(2) was found to be 399 cm(-1) and trends in physically meaningful components of electron binding energy, such as static Coulomb, dispersion, and polarization stabilizations, were determined for this series of clusters. The (2)Pi dipole-bound anionic state was found for the pentamer with the MP2 vertical electron detachment energy of 92 cm(-1). (C) 1999 Elsevier Science B.V. All rights reserved. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. Univ Utah, Dept Chem, Salt Lake City, UT 84112 USA. Univ Gdansk, Dept Chem, PL-80952 Gdansk, Poland. RP Gutowski, M (reprint author), Pacific NW Natl Lab, Richland, WA 99352 USA. EM ms_gutowski@pnl.gov NR 35 TC 20 Z9 20 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD FEB 5 PY 1999 VL 300 IS 3-4 BP 331 EP 338 DI 10.1016/S0009-2614(98)01377-3 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 163XJ UT WOS:000078431800009 ER PT J AU Borzsak, I Cummings, PT AF Borzsak, I Cummings, PT TI Molecular dynamics simulation of ice XII SO CHEMICAL PHYSICS LETTERS LA English DT Article ID LIQUID WATER AB Molecular dynamics simulations have been performed on the newly discovered metastable ice XII. This new crystalline ice phase [C. Lobban, J.L. Finney, W.F. Kuhs, Nature (London) 391 (1998) 268] is proton-disordered. Thus 90 possible configurations of the unit cell can be constructed which differ only in the orientations of the water molecules. The simulation used the TIP4P potential model for water at constant temperature and density. About one-quarter of the initial configurations did not melt in the course of the simulation. This result is supportive of the experimental structure and also demonstrates the ability of this water model to study ice phases. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Tennessee, Dept Chem Engn, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. RP Borzsak, I (reprint author), Univ Tennessee, Dept Chem Engn, 419 Dougherty Engn Bldg, Knoxville, TN 37996 USA. RI Cummings, Peter/B-8762-2013 OI Cummings, Peter/0000-0002-9766-2216 NR 9 TC 9 Z9 9 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD FEB 5 PY 1999 VL 300 IS 3-4 BP 359 EP 363 DI 10.1016/S0009-2614(98)01387-6 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 163XJ UT WOS:000078431800013 ER PT J AU Snodgrass, JW Ackerman, JW Bryan, AL Burger, J AF Snodgrass, JW Ackerman, JW Bryan, AL Burger, J TI Influence of hydroperiod, isolation, and heterospecifics on the distribution of aquatic salamanders (siren and amphiuma) among depression wetlands SO COPEIA LA English DT Article ID COMMUNITY STRUCTURE AB We used occurrence data gathered over a four-year period to assess relationships among hydroperiod length (amount of time a wetland holds water during a year), wetland isolation from other aquatic habitats, and the occurrence of sirens (Siren intermedia and S. lacertina) and amphiumas (Amphiuma means) among depression wetlands of the upper Atlantic Coastal Plain. The combined occurrence of sirens and amphiumas was positively correlated with hydroperiod length and negatively correlated with distance to the nearest intermittent aquatic habitat. Occurrences of individual species were negatively correlated with either distance to the nearest intermittent aquatic habitat or elevation difference between wetlands and the nearest permanent aquatic habitat. Siren lacertina showed higher than expected allopatric distribution in relation to other species, suggesting biological interactions may further limit the distribution of sirens and amphiumas among depression wetlands. C1 Univ Georgia, Savannah River Ecol Lab, Aiken, SC 29802 USA. Rutgers State Univ, Environm & Occupat Hlth Sci Inst, Div Life Sci, Piscataway, NJ 08855 USA. Rutgers State Univ, Environm & Occupat Hlth Sci Inst, CRESP, Piscataway, NJ 08855 USA. RP Snodgrass, JW (reprint author), Univ Georgia, Savannah River Ecol Lab, Drawer E, Aiken, SC 29802 USA. RI Snodgrass, Joel/C-5288-2016; OI Snodgrass, Joel/0000-0002-4436-8750 NR 23 TC 32 Z9 38 U1 0 U2 6 PU AMER SOC ICHTHYOLOGISTS HERPETOLOGISTS PI CHARLESTON PA UNIV CHARLESTON, GRICE MARINE LABORATORY, 205 FORT JOHNSON RD, CHARLESTON, SC 29412 USA SN 0045-8511 J9 COPEIA JI Copeia PD FEB 5 PY 1999 IS 1 BP 107 EP 113 PG 7 WC Zoology SC Zoology GA 167TY UT WOS:000078650400013 ER PT J AU Wu, JZ Prausnitz, JM AF Wu, JZ Prausnitz, JM TI Osmotic pressures of aqueous bovine serum albumin solutions at high ionic strength SO FLUID PHASE EQUILIBRIA LA English DT Article DE osmotic pressure; proteins; RPA theory AB Using osmometers similar to those described by Vilker et al. [V.L. Vilker, C.K. Colton, K.A. Smith, J. Colloid and Interface Sci. 79 (1981) 548-566] and Amos et al. [D.A. Amos, C.J. Radke, S. Lynn, J. Phys. Chem. B 102 (1998) 2739-2753], osmotic pressures of aqueous bovine serum albumin (BSA) solutions were measured at three pH (4.5, 5.4, 7.4) and at different sodium chloride concentrations (from 1 to 5 M). Experimental data were compared with results calculated from two van der Waals-type models using a potential of mean force including hard-sphere and double-layer repulsions, and van der Waals attraction. In both models, the Carnahan-Starling equation of state represents the contribution of the hard-sphere repulsion to the osmotic pressure. Van der Waals attraction and double-layer repulsion are represented by their contributions to the osmotic second virial coefficient in the first model, or in the second, to the random-phase-approximation (RPA). Although both models give a semi-quantitative description of the osmotic pressures of BSA solutions at various conditions, the first model represents the data slightly better than the second, using the same number of adjustable parameters. Further improvement of modeling requires a more accurate potential of mean force for protein molecules in salt solution. (C) 1999 Elsevier Science B.V. All rights reserved. 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. RI Wu, Jianzhong/I-5164-2013; OI Wu, Jianzhong/0000-0002-4582-5941 NR 17 TC 41 Z9 44 U1 2 U2 16 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-3812 J9 FLUID PHASE EQUILIBR JI Fluid Phase Equilib. PD FEB 5 PY 1999 VL 155 IS 1 BP 139 EP 154 DI 10.1016/S0378-3812(98)00435-X PG 16 WC Thermodynamics; Chemistry, Physical; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA 170DT UT WOS:000078791500010 ER PT J AU Quaite-Randall, E Joachimiak, A AF Quaite-Randall, E Joachimiak, A TI Purification of chaperonins SO JOURNAL OF CHROMATOGRAPHY B LA English DT Review DE reviews; chaperonins ID T-COMPLEX POLYPEPTIDE-1; ARCHAEON SULFOLOBUS-SOLFATARICUS; ESCHERICHIA-COLI; HEAT-SHOCK; MOLECULAR CHAPERONE; THERMOPHILIC ARCHAEBACTERIUM; MITOCHONDRIAL CHAPERONIN-60; FUNCTIONAL-CHARACTERIZATION; INTRACELLULAR SYMBIONT; EUKARYOTIC CHAPERONIN AB The availability of protein samples of sufficient quality and in sufficient quantity is a driving force in biology and biotechnology. Protein samples that are free of critical contaminants are required for specific assays, Large amounts of highly homogeneous and reproducible material are needed for crystallography and nuclear magnetic resonance studies of protein structure. Protein-based therapeutic factors used in human medicine must not contain any contaminants that might interfere with treatment. The roles played by molecular chaperones in protein folding and in many cellular processes make these proteins very attractive candidates as biochemical reagents, and the class of chaperones called chaperonins is one of the most important candidates. Methods for successfully purifying chaperonins are needed to advance the field of chaperonin-mediated protein folding. This article outlines the strategies and methods used to obtain pure chaperonin samples from different biological sources. The objective is to help new researchers obtain better quality samples of chaperonins from many new organisms. (C) 1999 Published by Elsevier Science B.V. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Joachimiak, A (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 76 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4347 J9 J CHROMATOGR B JI J. Chromatogr. B PD FEB 5 PY 1999 VL 722 IS 1-2 BP 153 EP 177 DI 10.1016/S0378-4347(98)00503-9 PG 25 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 165ZE UT WOS:000078551100010 PM 10068139 ER PT J AU Mariappan, SVS Catasti, P Silks, LA Bradbury, EM Gupta, G AF Mariappan, SVS Catasti, P Silks, LA Bradbury, EM Gupta, G TI The high-resolution structure of the triplex formed by the GAA/TTC triplet repeat associated with Friedreich's ataxia SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE Friedreich's ataxia; GAA repeats; triplex at physiological pH; folding of the TTC strand ID INTRAMOLECULAR DNA TRIPLEXES; DISTANCE GEOMETRY METHOD; MOLECULAR-CONFORMATION; SUPERCOILED PLASMIDS; NMR-SPECTROSCOPY; HUMAN-DISEASE; EXPANSION; HAIRPINS; SPECTRA; INSTABILITY AB Expansions of the triplet repeat, GAA/TTC, inside the first intron of the frataxin gene causes Friedreich's ataxia (FRDA). It was of interest to us to examine whether the FRDA repeat forms an unusual DNA structure, since formation of such structure during replication may cause its expansion. Here, we show that the FRDA repeat forms a tripler in which the TTC strand folds on either side of the same GAA strand. We have determined the high-resolution NMR structures of two intramolecularly folded FRDA triplexes, (GAA)(2)T-4(TTC)(2)T-4(CTT)(2) and (GAA)(2)T-4(TTC)(2)T2CT2(CTT)(2) with T . A . T and C+. G . C triads. T-4 represents a synthetic loop sequence, whereas T2CT2 is the natural loop-folding sequence of the TTC strand. We have also made use of site-specific N-15-labeling of the cytosine residues to investigate their protonation status and their interaction with other protons. We show that the cytosine residues of the Hoogsteen C+. G pairs in this triplex are protonated close to physiological pH. Therefore, it appears that the triplex formation offers a plausible explanation for the expansion of the GAA/TTC repeats in FRDA. C1 Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Natl Stable Isotope Resource, Los Alamos, NM 87545 USA. Univ Calif Davis, Sch Med, Dept Biol Chem, Davis, CA 95616 USA. RP Gupta, G (reprint author), Univ Calif Los Alamos Natl Lab, Div Life Sci, T-10,MS-K710, Los Alamos, NM 87545 USA. EM gxg@lanl.gov NR 51 TC 59 Z9 59 U1 0 U2 6 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-2836 J9 J MOL BIOL JI J. Mol. Biol. PD FEB 5 PY 1999 VL 285 IS 5 BP 2035 EP 2052 DI 10.1006/jmbi.1998.2435 PG 18 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 164DQ UT WOS:000078447500011 PM 9925783 ER PT J AU McDonald, JP Peat, TS Levine, AS Woodgate, R AF McDonald, JP Peat, TS Levine, AS Woodgate, R TI Intermolecular cleavage by UmuD-like enzymes: Identification of residues required for cleavage and substrate specificity SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE enzymatic reactions; Escherichia coli UmuD; protein-protein interactions; Salmonella typhimurium UmuD; SOS mutagenesis ID RECA-MEDIATED CLEAVAGE; SOS MUTATOR ACTIVITY; ESCHERICHIA-COLI; LEXA CLEAVAGE; MUCA PROTEIN; MUTAGENESIS; ACTIVATION; REPRESSORS; DAMAGE AB The UmuD-like proteins are best characterized for their role in damage-induced SOS mutagenesis. An essential step in this process is the enzymatic self-processing of the UmuD-like proteins. This reaction is thought to occur either via an intramolecular or intermolecular self-cleavage mechanism. Here, we demonstrate that it can also occur via an heterologous intermolecular cleavage reaction. The Escherichia coli UmuD enzyme demonstrated the broadest substrate specificity, cleaving both E. coli and Salmonella typhimurium UmuD substrates in vivo. In comparison, the wild-type S. typhimurium UmuD (UmuD(St)) and MucA enzymes catalyzed intermolecular self-cleavage, but did not facilitate heterologous cleavage. Heterologous cleavage by the UmuD(St) enzyme was, however, observed with chimeric UmuD substrates that possess residues 30-55 of UmuD(St). We have further localized the residue predominantly responsible for UmuD(St)-catalyzed heterologous cleavage to Ser50 in the substrate molecule. We hypothesize that changes at this residue affect the positioning of the cleavage site of a substrate molecule within the catalytic cleft of the UmuD(St) enzyme by affecting the formation of a so-called UmuD "filament-dimer". This hypothesis is further supported by the observation that mutations known to disrupt an E. coli UmuD' filament dimer also block intermolecular UmuD(Ec) cleavage. (C) 1999 Academic Press. C1 NICHHD, Sect DNA Replicat Repair & Mutagenesis, NIH, Bethesda, MD 20892 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Woodgate, R (reprint author), NICHHD, Sect DNA Replicat Repair & Mutagenesis, NIH, Bethesda, MD 20892 USA. EM woodgate@helix.nih.gov RI Peat, Thomas/F-9817-2010 OI Peat, Thomas/0000-0002-6488-0831 NR 33 TC 18 Z9 18 U1 0 U2 0 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-2836 J9 J MOL BIOL JI J. Mol. Biol. PD FEB 5 PY 1999 VL 285 IS 5 BP 2199 EP 2209 DI 10.1006/jmbi.1998.2433 PG 11 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 164DQ UT WOS:000078447500022 PM 9925794 ER PT J AU Curtright, T Zachos, C AF Curtright, T Zachos, C TI Wigner trajectory characteristics in phase space and field theory SO JOURNAL OF PHYSICS A-MATHEMATICAL AND GENERAL LA English DT Article ID DEFORMATION THEORY; QUANTUM-MECHANICS; QUANTIZATION; FORMULATION; ALGEBRA; MODELS AB Exact characteristic trajectories are specified for the time-propagating Wigner phase space distribution function. They are especially simple-indeed, classical-for the quantized simple harmonic oscillator, which serves as the underpinning of the field theoretic Wigner functional formulation introduced. Scalar field theory is thus reformulated in terms of distributions in held phase space. Applications to duality transformations in field theory are discussed. C1 Univ Miami, Dept Phys, Coral Gables, FL 33124 USA. Argonne Natl Lab, Div High Energy Phys, Argonne, IL 60439 USA. RP Curtright, T (reprint author), Univ Miami, Dept Phys, Box 248046, Coral Gables, FL 33124 USA. EM curtright@physics.miami.edu; zachos@hep.anl.gov RI Curtright, Thomas/B-6840-2015; OI Curtright, Thomas/0000-0001-7031-5604 NR 34 TC 30 Z9 30 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 FEB 5 PY 1999 VL 32 IS 5 BP 771 EP 779 DI 10.1088/0305-4470/32/5/009 PG 9 WC Physics, Multidisciplinary; Physics, Mathematical SC Physics GA 167JN UT WOS:000078628900009 ER PT J AU Thanos, CD Goodwill, KE Bowie, JU AF Thanos, CD Goodwill, KE Bowie, JU TI Oligomeric structure of the human EphB2 receptor SAM domain SO SCIENCE LA English DT Article ID MAXIMUM-LIKELIHOOD; CRYSTAL-STRUCTURES; TYROSINE KINASES; PROTEIN; FUSION; TEL; LEUKEMIA; GENE; ASSOCIATION; REFINEMENT AB The sterile alpha motif (SAM) domain is a protein interaction module that is present in diverse signal-transducing proteins. SAM domains are known to form homo- and hetero-oligomers. The crystal structure of the SAM domain from an Eph receptor tyrosine kinase, EphB2, reveals two Large interfaces. In one interface, adjacent monomers exchange amino-terminal peptides that insert into a hydrophobic groove on each neighbor. A second interface is composed of the carboxyl-terminal helix and a nearby Loop. A possible oligomer, constructed from a combination of these binding modes, may provide a platform for the formation of larger protein complexes. C1 Univ Calif Los Angeles, US DOE, Lab Struct Biol & Mol Med, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Chem, Los Angeles, CA 90095 USA. RP Bowie, JU (reprint author), Univ Calif Los Angeles, US DOE, Lab Struct Biol & Mol Med, Los Angeles, CA 90095 USA. EM bowie@mbi.ucla.edu NR 44 TC 170 Z9 174 U1 0 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 FEB 5 PY 1999 VL 283 IS 5403 BP 833 EP 836 DI 10.1126/science.283.5403.833 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 165AT UT WOS:000078496800041 PM 9933164 ER PT J AU Skurski, P Gutowski, M Simons, J AF Skurski, P Gutowski, M Simons, J TI Dipole-bound anion of the HNNH3 isomer of hydrazine. An ab initio study SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID ABINITIO ELECTRONIC-STRUCTURE; ABSORPTION CROSS-SECTIONS; POLAR-MOLECULES; NEGATIVE-IONS; UV ABSORPTION; STATES; ENERGY; ATOMS; N2H4; CH3CN AB The possibility of electron binding to the HNNH3 and H2NNH2 tautomers of hydrazine was studied at the coupled cluster level of theory with single, double, and noniterative triple excitations. The HNNH3 tautomer, with a dipole moment of 5.4 D, binds an electron by 1076 cm(-1) whereas the H2NNH2 tautomer forms neither a dipole- nor valence-bound anionic state. It is suggested that the HNNH3 tautomer, which is kinetically stable but thermodynamically unstable relative to H2NNH2, may be formed by photodetachment from the N2H4- species examined in this work. C1 Univ Utah, Dept Chem, Salt Lake City, UT 84112 USA. Univ Gdansk, Dept Chem, PL-80952 Gdansk, Poland. Pacific NW Lab, Richland, WA 99352 USA. RP Simons, J (reprint author), Univ Utah, Dept Chem, Salt Lake City, UT 84112 USA. NR 61 TC 26 Z9 26 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD FEB 4 PY 1999 VL 103 IS 5 BP 625 EP 631 DI 10.1021/jp9836776 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 174PB UT WOS:000079042600012 ER PT J AU Nash, CS Bursten, BE AF Nash, CS Bursten, BE TI Spin-orbit effects on the electronic structure of heavy and superheavy hydrogen halides: Prediction of an anomalously strong bond in H[117] SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID CONFIGURATION-INTERACTION CALCULATIONS; MOLECULAR-PROPERTIES; QUANTUM-CHEMISTRY; BR; PSEUDOPOTENTIALS; ELEMENT-118; SPECTRA; HAT; HBR AB The bond lengths, vibrational frequencies, and bond dissociation energies of the heavy and superheavy hydrogen halides HBr, HI, HAt and H[117] ([117] = element 117) have been calculated by using multireference relativistic configuration interaction (MR-RCI) and coupled-cluster [CCSD(T)] electronic structure methods. The effects of spin-orbit coupling on the coupled-cluster calculations were approximated by adding a correction term that represents the spin-orbit effect on the energy in the MR-RCI calculations, The calculated values are in good accord with the available experimental and theoretical data for HBr, HI, and HAt, with the latter predicted to have a bond length of 1.74 Angstrom and a dissociation energy of 1.37 eV via the corrected CCSD(T) calculations. By using the same method, H[117] is predicted to have a bond length of 1.94 Angstrom, a vibrational frequency of 1648 cm(-1), and a dissociation energy of 2.21 eV; i.e., it is predicted to have a significantly longer but only marginally weaker bond than HAt. This prediction is explained via strong spin-orbit effects, which cause the 8s orbital of [117] to be involved in the bonding. C1 Ohio State Univ, Dept Chem, Columbus, OH 43210 USA. Lawrence Livermore Natl Lab, Glenn T Seaborg Inst Transactinium Sci, Livermore, CA 94550 USA. RP Bursten, BE (reprint author), Ohio State Univ, Dept Chem, 120 W 18th Ave, Columbus, OH 43210 USA. NR 38 TC 24 Z9 24 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 FEB 4 PY 1999 VL 103 IS 5 BP 632 EP 636 DI 10.1021/jp9843407 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 174PB UT WOS:000079042600013 ER PT J AU Wang, ZL Bentley, J Evans, ND AF Wang, ZL Bentley, J Evans, ND TI Mapping the valence states of transition-metal elements using energy-filtered transmission electron microscopy SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Letter ID LOSS SPECTROSCOPY; CONVERSION AB The properties of transition-metal oxides are related to the presence of elements with mixed valences, such as Mn and Co. Spatial mapping of the valence-state distribution of transition-metal elements is a challenge to existing microscopy techniques. In this letter, using the valence-state information provided by the white lines observed in electron energy-loss spectroscopy in a transmission electron microscope (TEM), an experimental approach is demonstrated to map the valence-state distributions of Mn and Co using the energy-filtered filtered TEM. An optimum spatial resolution of similar to 2 nm has been achieved for two-phase Co oxides with sharp boundaries. This provides a new technique for quantifying the valence states of cations in magnetic oxides. C1 Georgia Inst Technol, Sch Mat Sci & Engn, Atlanta, GA 30332 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Wang, ZL (reprint author), Georgia Inst Technol, Sch Mat Sci & Engn, Atlanta, GA 30332 USA. RI Evans, Neal/F-5955-2011; Wang, Zhong Lin/E-2176-2011 OI Wang, Zhong Lin/0000-0002-5530-0380 NR 10 TC 15 Z9 15 U1 0 U2 7 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 FEB 4 PY 1999 VL 103 IS 5 BP 751 EP 753 DI 10.1021/jp9841135 PG 3 WC Chemistry, Physical SC Chemistry GA 174PH UT WOS:000079043200002 ER PT J AU Rodriguez, JA Chaturvedi, S Hanson, JC Brito, JL AF Rodriguez, JA Chaturvedi, S Hanson, JC Brito, JL TI Reaction of H-2 and H2S with CoMoO4 and NiMoO4: TPR, XANES, time-resolved XRD, and molecular-orbital studies SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID X-RAY-ABSORPTION; TRANSITION-METAL OXIDES; PHASE-COMPOSITION; NICKEL MOLYBDATE; FINE-STRUCTURE; SURFACES; CATALYSTS; SULFUR; SITES; CHEMISORPTION AB The combination of two metals in an oxide matrix can produce materials with novel physical and chemical properties. The reactivity of a series of cobalt and nickel molybdates (alpha-AMoO(4), beta-AMoO(4), and AMoO(4) nH(2)O; A = Co or Ni) toward H-2 and H2S was examined using temperature programmed reduction (TPR), synchrotron-based X-ray powder diffraction (XRD), and X-ray absorption near-edge spectroscopy (XANES). In general, the cobalt and nickel molybdates an more reactive toward H-2 and easier to reduce than pure molybdenum oxides: MoO2 < MoO3 < CoMoO4 < NiMoO4. The interaction of H-2 With surfaces of alpha-NiMoO4, alpha-CoMoO4, and alpha-MoO3 was investigated using ab initio SCF calculations and cluster models. The mixed-metal oxides are easier to reduce due to the combination of two factors. First, it is easier to adsorb and dissociate H-2 on Ni or Co sites than on Mo sites of an oxide. And second, as a result of differences in the strength of the metal-oxygen bonds, it is easier to remove oxygen as water from the nickel and cobalt molybdates than from MoO3 or MoO2. The extra reactivity that the Co and Ni atoms provide also makes the rate of sulfidation of the cobalt and nickel molybdates faster than that of purr molybdenum oxides. For the adsorption of H2S, HS, and S on alpha-NiMoO4 and alpha-MoO3 clusters, the results of ab initio SCF calculations show bigger bonding energies on the Ni sites than on the Mo sites. In these systems, the oxidation state of the Ni atoms is substantially lower (i.e., larger electron density) than that of the Mo atoms, favoring the formation of Ni --> SH and Ni --> S dative bonds. The behavior of the cobalt and nickel molybdates is a very good example of how one can enhance the chemical activity of an oxide (MoO3) by adding a second metal cation to the system. Results of time-resolved XRD and XANES indicate that the reduced AMoO(4) compounds can be regenerated by reaction with O-2 at high temperatures (350-450 degrees C). A similar procedure (S-a + O-2,O-gas --> SO2,gas) can be used to remove most of the sulfur from the sulfided oxides. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Inst Venezolano Invest Cient, Ctr Quim, Caracas 1020A, Venezuela. RP Rodriguez, JA (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RI Brito, Joaquin/F-4974-2010; Hanson, jonathan/E-3517-2010 NR 80 TC 69 Z9 69 U1 7 U2 36 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 FEB 4 PY 1999 VL 103 IS 5 BP 770 EP 781 DI 10.1021/jp983115m PG 12 WC Chemistry, Physical SC Chemistry GA 174PH UT WOS:000079043200005 ER PT J AU Schlichthorl, G Park, NG Frank, AJ AF Schlichthorl, G Park, NG Frank, AJ TI Evaluation of the charge-collection efficiency of dye-sensitized nanocrystalline TiO2 solar cells SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID MODULATED PHOTOCURRENT SPECTROSCOPY; PHOTOELECTROCHEMICAL CELLS; ELECTRONIC TRANSPORT; RECOMBINATION; FILMS AB Intensity modulated photovoltage spectroscopy (IMVS) and intensity modulated photocurrent spectroscopy (IMPS) are used to evaluate the charge-collection efficiency of dye-sensitized nanocrystalline TiO2 solar cells. The charge-collection efficiency of the photoinjected electrons from dye sensitization is estimated from the respective time constants for charge recombination at open circuit tau(oc) and the combined processes of charge collection and charge recombination at short circuit tau(sc) obtained by IMVS and IMPS measurements. Three models are developed for relating the charge-collection efficiency to tau(oc)/tau(sc). The first model determines the charge-collection efficiency from tau(oc)/tau(sc) without considering the underlying physical processes measured by IMVS and IMPS. The second model obtains tau(oc)/tau(sc) by simulating the frequency response of IMVS and IMPS from the time-dependent continuity equation for simplified conditions. The third model determines the time constants for IMVS and IMPS from electron-concentration profiles calculated for constant light intensity and more realistic conditions. To obtain a realistic steady-state electron concentration profile, a nonlinear dependence of the rate of recombination on the electron concentration in the TiO2 film is considered. Furthermore, the continuity equation is modified to account for charge trapping and detrapping. For the first time, expressions are derived for calculating the time constants from the steady-state electron concentration profile. The validity of this method is demonstrated for the second model from which the exact IMPS and IMVS responses are calculated. The three models are compared with each other. A simple expression is derived for calculating the charge-collection efficiency from the measured values of tau(oc)/tau(sc) and the light intensity dependence of tau(oc). C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Frank, AJ (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Park, Nam-Gyu/F-2477-2014 NR 18 TC 328 Z9 331 U1 5 U2 81 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 FEB 4 PY 1999 VL 103 IS 5 BP 782 EP 791 DI 10.1021/jp9831177 PG 10 WC Chemistry, Physical SC Chemistry GA 174PH UT WOS:000079043200006 ER PT J AU Taylor, RS Garrett, BC AF Taylor, RS Garrett, BC TI Accommodation of alcohols by the liquid/vapor interface of water: Molecular dynamics study SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID TRANSITION-STATE THEORY; VAPOR INTERFACE; GAS-PHASE; MASS ACCOMMODATION; AQUEOUS SURFACES; THERMODYNAMIC PROPERTIES; ION-PAIR; HETEROGENEOUS CHEMISTRY; ORIENTATIONAL STRUCTURE; TEMPERATURE-DEPENDENCE AB Molecular dynamics computer simulations have been used in conjunction with statistical mechanical perturbation theory to examine the process by which water, ethanol, and ethylene glycol (1,2-ethanediol) molecules are transported from the vapor phase into bulk water. The calculated energetics for solvation in the bulk liquid and surface properties such as the surface tension of water and orientations of ethanol and ethylene glycol adsorbed at the water interface agree well with the corresponding experimental data, Currently, the uptake of trace species by water droplets is generally modeled by decoupling the process of mass accommodation at the interface from gas- and liquid-phase diffusion and then coupling the independent processes using an electrical resistance model. In the resistance model, the mass-accommodation coefficient is a measure of the competition between the kinetics of solvation into the bulk liquid and the kinetics of desorption back into the gas phase. Interpreting experimental uptake rates of a variety of solute molecules by water using the resistance model requires mass-accommodation coefficients that are less than 0.5. Mass-accommodation coefficients less than 0.5 imply that the rate of desorption is greater than solvation, thus suggesting that the free energy of activation for desorption is less than that for solvation. The calculated equilibrium free-energy curves for transporting water, ethanol, and ethylene glycol molecules across the liquid/vapor interface and into bulk water exhibit barriers to solvation that are considerably smaller than those implied by the resistance model. Nonequilibrium solvation or dynamical solvent effects on the calculated activation free energies have also been estimated and are shown to be too small to account for the large difference in comparison with the resistance model. In addition, the temperature dependence of this barrier for ethanol has been calculated. Although this dependence agrees with that predicted by the resistance model, the heights of the calculated barriers are again much lower than those predicted by the model. C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Garrett, BC (reprint author), Pacific NW Lab, Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. RI Garrett, Bruce/F-8516-2011 NR 79 TC 46 Z9 46 U1 0 U2 21 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 FEB 4 PY 1999 VL 103 IS 5 BP 844 EP 851 DI 10.1021/jp9832645 PG 8 WC Chemistry, Physical SC Chemistry GA 174PH UT WOS:000079043200015 ER PT J AU Young, DP Hall, D Torelli, ME Fisk, Z Sarrao, JL Thompson, JD Ott, HR Oseroff, SB Goodrich, RG Zysler, R AF Young, DP Hall, D Torelli, ME Fisk, Z Sarrao, JL Thompson, JD Ott, HR Oseroff, SB Goodrich, RG Zysler, R TI High-temperature weak ferromagnetism in a low-density free-electron gas SO NATURE LA English DT Article AB The magnetic properties of the ground state of a low-density free-electron gas in three dimensions have been the subject of theoretical speculation and controversy for seven decades(1). Not only is this a difficult theoretical problem to solve, it is also a problem which has not hitherto been directly addressed experimentally. Here we report measurements on electron-doped calcium hexaboride (CaB6) which, we argue, show that-at a density of 7 x 10(19) electrons cm(-3)-the ground state is ferromagnetically polarized with a saturation moment of 0.07 mu(B) per electron. Surprisingly, the magnetic ordering temperature of this itinerant ferromagnet is 600 K, of the order of the Fermi temperature of the electron gas. C1 Florida State Univ, NHMFL, Tallahassee, FL 32306 USA. Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87454 USA. ETH Honggerberg, Festkorperphys Lab, CH-8093 Zurich, Switzerland. San Diego State Univ, Dept Phys, San Diego, CA 92182 USA. Louisiana State Univ, Dept Phys, Baton Rouge, LA 70803 USA. Ctr Atom Bariloche, RA-8400 Bariloche, Rio Negro, Argentina. RP Fisk, Z (reprint author), Florida State Univ, NHMFL, Tallahassee, FL 32306 USA. EM fisk@magnet.fsu.edu NR 12 TC 361 Z9 364 U1 3 U2 34 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD FEB 4 PY 1999 VL 397 IS 6718 BP 412 EP 414 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 164KA UT WOS:000078461700040 ER PT J AU Hampel, W Handt, J Heusser, G Kiko, J Kirsten, T Laubenstein, M Pernicka, E Rau, W Wojcik, M Zakharov, Y Ammon, RV Ebert, KH Fritsch, T Heidt, D Henrich, E Stielglitz, L Weirich, F Balata, M Sann, M Hartmann, FX Bellotti, E Cattadori, C Cremonesi, O Ferrari, N Fiorini, E Zanotti, L Altmann, M von Feilitzsch, F Mossbauer, R Wanninger, S Berthomieu, G Schatzman, E Carmi, I Dostrovsky, I Bacci, C Belli, P Bernabei, R d'Angelo, S Paoluzi, L Cribier, M Rich, J Spiro, M Tao, C Vignaud, D Boger, J Hahn, RL Rowley, JK Stoenner, RW Weneser, J AF Hampel, W Handt, J Heusser, G Kiko, J Kirsten, T Laubenstein, M Pernicka, E Rau, W Wojcik, M Zakharov, Y Ammon, RV Ebert, KH Fritsch, T Heidt, D Henrich, E Stielglitz, L Weirich, F Balata, M Sann, M Hartmann, FX Bellotti, E Cattadori, C Cremonesi, O Ferrari, N Fiorini, E Zanotti, L Altmann, M von Feilitzsch, F Mossbauer, R Wanninger, S Berthomieu, G Schatzman, E Carmi, I Dostrovsky, I Bacci, C Belli, P Bernabei, R d'Angelo, S Paoluzi, L Cribier, M Rich, J Spiro, M Tao, C Vignaud, D Boger, J Hahn, RL Rowley, JK Stoenner, RW Weneser, J CA GALLEX Collaboration TI GALLEX solar neutrino observations: results for GALLEX IV SO PHYSICS LETTERS B LA English DT Article AB We report the GALLEX solar neutrino results for the measuring period GALLEX IV, from 14 February 1996 until 23 January 1997. Counting for the GALLEX IV runs was completed on 19 June 1997. The GALLEX IV result from 12 solar runs is [118.4 +/- 17.8 (stat.) +/- 6.6 (sys.)] SNU (1 sigma). The combined result for GALLEX I + II + III + IV, which comprises 65 solar runs, is 77.5 +/- 6.2(-4.7)(+4.3)(1 sigma) SNU. The GALLEX experimental program to register solar neutrinos has now been completed. In April 1998, GALLEX was succeeded by a new project, the Gallium Neutrino Observatory (GNO), with newly defined motives and goals. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Max Planck Inst Kernphys, D-69029 Heidelberg, Germany. Forschungszentrum Karlsruhe, Inst Tech Chem, D-760216021 Karlsruhe, Germany. Lab Nazl Gran Sasso, I-67010 Laquila, Italy. Univ Milan, Dipartimento Fis, I-20133 Milan, Italy. INFM, I-20133 Milan, Italy. Tech Univ Munich, Phys Dept E15, D-85747 Garching, Germany. Observ Cote Azur, Dept Cassini, F-06004 Nice 4, France. Hebrew Univ Jerusalem, Dept Environm & Energy Res, IL-76100 Rehovot, Israel. Univ Roma Tor Vergata, Dipartimento Fis, I-00133 Rome, Italy. INFM, Sez Roma 2, I-00133 Rome, Italy. CEA Saclay, DAPNIA, Serv Phys Particules, F-91191 Gif Sur Yvette, France. Brookhaven Natl Lab, Upton, NY 11973 USA. Jagiellonian Univ, Inst Fiz, PL-30059 Krakow, Poland. Russian Acad Sci, Inst Nucl Res, Moscow 117312, Russia. Univ Roma 3, Dipartimento Fis, I-00100 Rome, Italy. Fac Sci Luminy, CPPM, F-13288 Marseille 09, France. RP Hampel, W (reprint author), Max Planck Inst Kernphys, Postfach 103980, D-69029 Heidelberg, Germany. RI Belli, Pierluigi/H-1942-2012; Laubenstein, Matthias/C-4851-2013; Bernabei, Rita/C-1212-2016; OI Belli, Pierluigi/0000-0003-4517-4891; Laubenstein, Matthias/0000-0001-5390-4343; Bernabei, Rita/0000-0003-1786-5396; cattadori, carla maria/0000-0001-7885-6253 NR 23 TC 1117 Z9 1121 U1 2 U2 8 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 FEB 4 PY 1999 VL 447 IS 1-2 BP 127 EP 133 DI 10.1016/S0370-2693(98)01579-2 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 167XM UT WOS:000078660200018 ER PT J AU Acciarri, M Achard, P Adriani, O Aguilar-Benitez, M Alcaraz, J Alemanni, G Allaby, J Aloisio, A Alviggi, MG Ambrosi, G Anderhub, H Andreev, VP Angelescu, T Anselmo, F Arefiev, A Azemoon, T Aziz, T Bagnaia, P Baksay, L Balandras, A Ball, RC Banerjee, S Banerjee, S Banicz, K Barczyk, A Barillere, R Barone, L Bartalini, P Basile, M Battiston, R Bay, A Becattini, F Becker, U Behner, F Berdugo, J Berges, P Bertucci, B Betev, BL Bhattacharya, S Biasini, M Biland, A Bilei, GM Blaising, JJ Blyth, SC Bobbink, GJ Bock, R Bohm, A Boldizsar, L Borgia, B Bourilkov, D Bourquin, M Braccini, S Branson, JG Brigljevic, V Brochu, F Brock, IC Buffini, A Buijs, A Burger, JD Burger, WJ Busenitz, J Button, A Cai, XD Campanelli, M Capell, M Romeo, GC Carlino, G Cartacci, AM Casaus, J Castellini, G Cavallari, F Cavallo, N Cecchi, C Cerrada, M Cesaroni, F Chamizo, M Chang, YH Chaturvedi, UK Chemarin, M Chen, A Chen, G Chen, GM Chen, HF Chen, HS Chereau, X Chiefari, G Cifarelli, L Cindolo, F Civinini, C Clare, I Clare, R Coignet, G Colijn, AP Colino, N Costantini, S Cotorobai, F de la Cruz, B Csilling, A Dai, TS van Dalen, JA D'Alessandro, R de Asmundis, R Deglon, P Degre, A Deiters, K della Volpe, D Denes, P DeNotaristefani, F De Salvo, A Diemoz, M van Dierendonck, D Di Lodovico, F Dionisi, C Dittmar, M Dominguez, A Doria, A Dova, MT Duchesneau, D Dufournand, D Duinker, P Duran, I Easo, S El Mamouni, H Engler, A Eppling, FJ Erne, FC Extermann, P Fabre, M Faccini, R Falagan, MA Falciano, S Favara, A Fay, J Fedin, O Felcini, M Ferguson, T Ferroni, F Fesefeldt, H Fiandrini, E Field, JH Filthaut, F Fisher, PH Fisk, I Forconi, G Fredj, L Freudenreich, K Furetta, C Galaktionov, Y Ganguli, SN Garcia-Abia, P Gataullin, M Gau, SS Gentile, S Gheordanescu, N Giagu, S Goldfarb, S Gong, ZF Gratta, G Gruenewald, MW van Gulik, R Gupta, VK Gurtu, A Gutay, LJ Haas, D Hartmann, B Hasan, A Hatzifotiadou, D Hebbeker, T Herve, A Hidas, P Hirschfelder, J Hofer, H Holzner, G Hoorani, H Hou, SR Iashvili, I Jin, BN Jones, LW de Jong, P Josa-Mutuberria, I Khan, RA Kamrad, D Kapustinsky, JS Kaur, M Kienzle-Focacci, MN Kim, D Kim, DH Kim, JK Kim, SC Kinnison, WW Kirkby, A Kirkby, D Kirkby, J Kiss, D Kittel, W Klimentov, A Konig, AC Kopp, A Korolko, I Koutsenko, V Kraemer, RW Krenz, W Kunin, A Lacentre, P de Guevara, PL Laktineh, I Landi, G Lapoint, C Lassila-Perini, K Laurikainen, P Lavorato, A Lebeau, M Lebedev, A Lebrun, P Lecomte, P Lecoq, P Le Coultre, P Lee, HJ Le Goff, JM Leiste, R Leonardi, E Levtchenko, P Li, C Lin, CH Lin, WT Linde, FL Lista, L Liu, ZA Lohmann, W Longo, E Lu, W Lu, YS Lubelsmeyer, K Luci, C Luckey, D Luminari, L Lustermann, W Ma, WG Maity, M Majumder, G Malgeri, L Malinin, A Mana, C Mangeol, D Marchesini, P Marian, G Martin, JP Marzano, F Massaro, GGG Mazumdar, K McNeil, RR Mele, S Merola, L Meschini, M Metzger, WJ von der Mey, M Migani, D Mihul, A Milcent, H Mirabelli, G Mnich, J Molnar, P Monteleoni, B Moulik, T Mount, R Muanza, GS Muheim, F Muijs, AJM Nahn, S Napolitano, M Nessi-Tedaldi, F Newman, H Niessen, T Nippe, A Nisati, A Nowak, H Oh, YD Organtini, G Ostonen, R Palomares, C Pandoulas, D Paoletti, S Paolucci, P Park, HK Park, IH Pascale, G Passaleva, G Patricelli, S Paul, T Pauluzzi, M Paus, C Pauss, F Peach, D Pedace, M Pei, YJ Pensotti, S Perret-Gallix, D Petersen, B Petrak, S Pevsner, A Piccolo, D Pieri, M Piroue, PA Pistolesi, E Plyaskin, V Pohl, M Pojidaev, V Postema, H Pothier, J Produit, N Prokofiev, D Quartieri, J Rahal-Callot, G Raja, N Raacoita, PG Rattaggi, M Raven, G Razis, P Ren, D Rescigno, M Reucroft, S van Rhee, T Riemann, S Riles, K Robohm, A Rodin, J Roe, BP Romero, L Rosier-Lees, S Roth, S Rubio, JA Ruschmeier, D Rykaczewski, H Sakar, S Salicio, J Sanchez, E Sanders, MP Sarakinos, ME Schafer, C Schegelsky, V Schmidt-Kaerst, S Schmitz, D Scholz, N Schopper, H Schotanus, DJ Schwenke, J Schwering, G Sciacca, C Sciarrino, D Servoli, L Shevchenko, S Shivarov, N Shoutko, V Shukla, J Shumilov, E Shvorob, A Siedenburg, T Son, D Smith, B Spillantini, P Steuer, M Stickland, DP Stone, A Stone, H Stoyanov, B Straessner, A Sudhakar, K Sultanov, G Sun, LZ Suter, H Swain, JD Szillasi, Z Tang, XW Tauscher, L Taylor, L Timmermans, C Ting, SCC Ting, SM Tonwar, SC Toth, J Tully, C Tung, KL Uchida, Y Ulbricht, J Valente, E Vesztergombi, G Vetlitsky, I Viertel, G Villa, S Vivargent, M Vlachos, S Vogel, H Vogt, H Vorobiev, I Vorobyov, AA Vorvolakos, A Wadhwa, M Wallraff, W Wang, JC Wang, XL Wang, ZM Weber, A Wu, SX Wynhoff, S Xu, ZZ Yang, BZ Yang, CG Yang, HJ Yang, M Ye, JB Yeh, SC You, JM Zalite, A Zalite, Y Zemp, P Zeng, Y Zhang, ZP Zhu, GY Zhu, RY Zichichi, A Ziegler, F Zilizi, G AF Acciarri, M Achard, P Adriani, O Aguilar-Benitez, M Alcaraz, J Alemanni, G Allaby, J Aloisio, A Alviggi, MG Ambrosi, G Anderhub, H Andreev, VP Angelescu, T Anselmo, F Arefiev, A Azemoon, T Aziz, T Bagnaia, P Baksay, L Balandras, A Ball, RC Banerjee, S Banerjee, S Banicz, K Barczyk, A Barillere, R Barone, L Bartalini, P Basile, M Battiston, R Bay, A Becattini, F Becker, U Behner, F Berdugo, J Berges, P Bertucci, B Betev, BL Bhattacharya, S Biasini, M Biland, A Bilei, GM Blaising, JJ Blyth, SC Bobbink, GJ Bock, R Bohm, A Boldizsar, L Borgia, B Bourilkov, D Bourquin, M Braccini, S Branson, JG Brigljevic, V Brochu, F Brock, IC Buffini, A Buijs, A Burger, JD Burger, WJ Busenitz, J Button, A Cai, XD Campanelli, M Capell, M Romeo, GC Carlino, G Cartacci, AM Casaus, J Castellini, G Cavallari, F Cavallo, N Cecchi, C Cerrada, M Cesaroni, F Chamizo, M Chang, YH Chaturvedi, UK Chemarin, M Chen, A Chen, G Chen, GM Chen, HF Chen, HS Chereau, X Chiefari, G Cifarelli, L Cindolo, F Civinini, C Clare, I Clare, R Coignet, G Colijn, AP Colino, N Costantini, S Cotorobai, F de la Cruz, B Csilling, A Dai, TS van Dalen, JA D'Alessandro, R de Asmundis, R Deglon, P Degre, A Deiters, K della Volpe, D Denes, P DeNotaristefani, F De Salvo, A Diemoz, M van Dierendonck, D Di Lodovico, F Dionisi, C Dittmar, M Dominguez, A Doria, A Dova, MT Duchesneau, D Dufournand, D Duinker, P Duran, I Easo, S El Mamouni, H Engler, A Eppling, FJ Erne, FC Extermann, P Fabre, M Faccini, R Falagan, MA Falciano, S Favara, A Fay, J Fedin, O Felcini, M Ferguson, T Ferroni, F Fesefeldt, H Fiandrini, E Field, JH Filthaut, F Fisher, PH Fisk, I Forconi, G Fredj, L Freudenreich, K Furetta, C Galaktionov, Y Ganguli, SN Garcia-Abia, P Gataullin, M Gau, SS Gentile, S Gheordanescu, N Giagu, S Goldfarb, S Gong, ZF Gratta, G Gruenewald, MW van Gulik, R Gupta, VK Gurtu, A Gutay, LJ Haas, D Hartmann, B Hasan, A Hatzifotiadou, D Hebbeker, T Herve, A Hidas, P Hirschfelder, J Hofer, H Holzner, G Hoorani, H Hou, SR Iashvili, I Jin, BN Jones, LW de Jong, P Josa-Mutuberria, I Khan, RA Kamrad, D Kapustinsky, JS Kaur, M Kienzle-Focacci, MN Kim, D Kim, DH Kim, JK Kim, SC Kinnison, WW Kirkby, A Kirkby, D Kirkby, J Kiss, D Kittel, W Klimentov, A Konig, AC Kopp, A Korolko, I Koutsenko, V Kraemer, RW Krenz, W Kunin, A Lacentre, P de Guevara, PL Laktineh, I Landi, G Lapoint, C Lassila-Perini, K Laurikainen, P Lavorato, A Lebeau, M Lebedev, A Lebrun, P Lecomte, P Lecoq, P Le Coultre, P Lee, HJ Le Goff, JM Leiste, R Leonardi, E Levtchenko, P Li, C Lin, CH Lin, WT Linde, FL Lista, L Liu, ZA Lohmann, W Longo, E Lu, W Lu, YS Lubelsmeyer, K Luci, C Luckey, D Luminari, L Lustermann, W Ma, WG Maity, M Majumder, G Malgeri, L Malinin, A Mana, C Mangeol, D Marchesini, P Marian, G Martin, JP Marzano, F Massaro, GGG Mazumdar, K McNeil, RR Mele, S Merola, L Meschini, M Metzger, WJ von der Mey, M Migani, D Mihul, A Milcent, H Mirabelli, G Mnich, J Molnar, P Monteleoni, B Moulik, T Mount, R Muanza, GS Muheim, F Muijs, AJM Nahn, S Napolitano, M Nessi-Tedaldi, F Newman, H Niessen, T Nippe, A Nisati, A Nowak, H Oh, YD Organtini, G Ostonen, R Palomares, C Pandoulas, D Paoletti, S Paolucci, P Park, HK Park, IH Pascale, G Passaleva, G Patricelli, S Paul, T Pauluzzi, M Paus, C Pauss, F Peach, D Pedace, M Pei, YJ Pensotti, S Perret-Gallix, D Petersen, B Petrak, S Pevsner, A Piccolo, D Pieri, M Piroue, PA Pistolesi, E Plyaskin, V Pohl, M Pojidaev, V Postema, H Pothier, J Produit, N Prokofiev, D Quartieri, J Rahal-Callot, G Raja, N Raacoita, PG Rattaggi, M Raven, G Razis, P Ren, D Rescigno, M Reucroft, S van Rhee, T Riemann, S Riles, K Robohm, A Rodin, J Roe, BP Romero, L Rosier-Lees, S Roth, S Rubio, JA Ruschmeier, D Rykaczewski, H Sakar, S Salicio, J Sanchez, E Sanders, MP Sarakinos, ME Schafer, C Schegelsky, V Schmidt-Kaerst, S Schmitz, D Scholz, N Schopper, H Schotanus, DJ Schwenke, J Schwering, G Sciacca, C Sciarrino, D Servoli, L Shevchenko, S Shivarov, N Shoutko, V Shukla, J Shumilov, E Shvorob, A Siedenburg, T Son, D Smith, B Spillantini, P Steuer, M Stickland, DP Stone, A Stone, H Stoyanov, B Straessner, A Sudhakar, K Sultanov, G Sun, LZ Suter, H Swain, JD Szillasi, Z Tang, XW Tauscher, L Taylor, L Timmermans, C Ting, SCC Ting, SM Tonwar, SC Toth, J Tully, C Tung, KL Uchida, Y Ulbricht, J Valente, E Vesztergombi, G Vetlitsky, I Viertel, G Villa, S Vivargent, M Vlachos, S Vogel, H Vogt, H Vorobiev, I Vorobyov, AA Vorvolakos, A Wadhwa, M Wallraff, W Wang, JC Wang, XL Wang, ZM Weber, A Wu, SX Wynhoff, S Xu, ZZ Yang, BZ Yang, CG Yang, HJ Yang, M Ye, JB Yeh, SC You, JM Zalite, A Zalite, Y Zemp, P Zeng, Y Zhang, ZP Zhu, GY Zhu, RY Zichichi, A Ziegler, F Zilizi, G CA L3 Collaboration TI The Q(2) evolution of the hadronic photon structure function F-2(gamma) at LEP SO PHYSICS LETTERS B LA English DT Article ID L3 EXPERIMENT; PAIR PRODUCTION; HIGH-ENERGIES; DETECTOR; TRIGGER; Q2 AB New measurements at a centre-of-mass energy root s similar or equal to 183 GeV of the hadronic photon structure function F-2(gamma)(x) in the Q(2) interval, 9 GeV2 less than or equal to Q(2) less than or equal to 30 GeV2, are presented. The data, collected in 1997 with the L3 detector, correspond to an integrated luminosity of 51.9 pb(-1). Combining with the data taken at a centre-of-mass energy of 91 GeV, the evolution of F-2(gamma) With Q(2) is measured in the Q(2) range from 1.2 GeV2 to 30 GeV2. F-2(gamma) shows a linear growth with ln Q(2); the value of the slope alpha(-1)d F-2(gamma)(Q(2))/dlnQ(2) is measured in two x bins from 0.01 to 0.2 and is somewhat higher than predicted. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Rhein Westfal TH Aachen, Inst Phys 1, D-52056 Aachen, Germany. Rhein Westfal TH Aachen, Inst Phys 3, D-52056 Aachen, Germany. NIKHEF H, Natl Inst High Energy Phys, NL-1009 DB Amsterdam, Netherlands. Univ Amsterdam, NL-1009 DB Amsterdam, Netherlands. Univ Michigan, Ann Arbor, MI 48109 USA. Lab Annecy Le Vieux Phys Particules, IN2P3, CNRS, LAPP, F-74941 Annecy Le Vieux, France. Johns Hopkins Univ, Baltimore, MD 21218 USA. Univ Basel, Inst Phys, CH-4056 Basel, Switzerland. Louisiana State Univ, Baton Rouge, LA 70803 USA. Inst High Energy Phys, Beijing 100039, Peoples R China. Humboldt Univ, D-10099 Berlin, Germany. Univ Bologna, I-40126 Bologna, Italy. Ist Nazl Fis Nucl, Sez Bologna, I-40126 Bologna, Italy. Tata Inst Fundamental Res, Bombay 400005, Maharashtra, India. Northeastern Univ, Boston, MA 02115 USA. Inst Atom Phys, R-76900 Bucharest, Romania. Univ Bucharest, R-76900 Bucharest, Romania. Hungarian Acad Sci, Cent Res Inst Phys, H-1525 Budapest 114, Hungary. MIT, Cambridge, MA 02139 USA. Univ Florence, I-50125 Florence, Italy. Ist Nazl Fis Nucl, Sez Firenze, I-50125 Florence, Italy. CERN, European Lab Particle Phys, CH-1211 Geneva 23, Switzerland. FBLJA Project, World Lab, CH-1211 Geneva 23, Switzerland. Univ Geneva, CH-1211 Geneva 4, Switzerland. Chinese Univ Sci & Technol, USTC, Hefei 230029, Anhui, Peoples R China. SEFT, Res Inst High Energy Phys, SF-00014 Helsinki, Finland. Univ Lausanne, CH-1015 Lausanne, Switzerland. Ist Nazl Fis Nucl, Sez Lecce, I-73100 Lecce, Italy. Univ Lecce, I-73100 Lecce, Italy. Los Alamos Natl Lab, Los Alamos, NM 87544 USA. Univ Lyon 1, CNRS, IN2P3, Inst Phys Nucl Lyon, F-69622 Villeurbanne, France. CIEMAT, Ctr Invest Energet Medioambientales & Tecnol, E-28040 Madrid, Spain. Inst Theoret & Expt Phys, Moscow 117259, Russia. Ist Nazl Fis Nucl, Sez Napoli, I-80125 Naples, Italy. Univ Naples Federico II, I-80125 Naples, Italy. Univ Cyprus, Dept Nat Sci, Nicosia, Cyprus. Catholic Univ Nijmegen, NL-6525 ED Nijmegen, Netherlands. Natl Inst Nucl Phys & High Energy Phys, NL-6525 ED Nijmegen, Netherlands. CALTECH, Pasadena, CA 91125 USA. Ist Nazl Fis Nucl, Sez Perugia, I-06100 Perugia, Italy. Univ Perugia, I-06100 Perugia, Italy. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Princeton Univ, Princeton, NJ 08544 USA. Ist Nazl Fis Nucl, Sez Roma, I-00185 Rome, Italy. Univ Roma La Sapienza, I-00185 Rome, Italy. Russian Acad Sci, Inst Nucl Phys, St Petersburg, Russia. Univ Salerno, I-84100 Salerno, Italy. Ist Nazl Fis Nucl, I-84100 Salerno, Italy. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Santiago, Dept Fis Particulas Elementales, E-15706 Santiago, Spain. Bulgarian Acad Sci, Cent Lab Mechatron & Instrumentat, BU-1113 Sofia, Bulgaria. Korea Adv Inst Sci & Technol, Ctr High Energy Phys, Taejon 305701, South Korea. Univ Alabama, Tuscaloosa, AL 35486 USA. Univ Utrecht, NL-3584 CB Utrecht, Netherlands. NIKHEF H, NL-3584 CB Utrecht, Netherlands. Purdue Univ, W Lafayette, IN 47907 USA. Paul Scherrer Inst, CH-5232 Villigen, Switzerland. DESY, Inst Hochenergiephys, D-15738 Zeuthen, Germany. Swiss Fed Inst Technol, CH-8093 Zurich, Switzerland. Univ Hamburg, D-22761 Hamburg, Germany. Natl Cent Univ, Chungli 32054, Taiwan. Natl Tsing Hua Univ, Dept Phys, Taipei, Taiwan. RP Acciarri, M (reprint author), Ist Nazl Fis Nucl, Sez Milano, Via Celoria 16, I-20133 Milan, Italy. RI Achard, Pablo/C-2983-2009; Sanchez, Eusebio/H-5228-2015; Duran, Ignacio/H-7254-2015; Hoorani, Hafeez/D-1791-2013; Palomares, Carmen/H-7783-2015; Fedin, Oleg/H-6753-2016; Roth, Stefan/J-2757-2016; Di Lodovico, Francesca/L-9109-2016; Yang, Haijun/O-1055-2015; Fiandrini, Emanuele/C-4549-2008; D'Alessandro, Raffaello/F-5897-2015; Lista, Luca/C-5719-2008; Kirkby, Jasper/A-4973-2012; Servoli, Leonello/E-6766-2012; bertucci, bruna/J-5237-2012; Cavallo, Nicola/F-8913-2012; Cerrada, Marcos/J-6934-2014; de la Cruz, Begona/K-7552-2014; Josa, Isabel/K-5184-2014; Vogel, Helmut/N-8882-2014; Ferguson, Thomas/O-3444-2014; Berdugo, Javier/A-2858-2015 OI Castellini, Guido/0000-0002-0177-0643; Diemoz, Marcella/0000-0002-3810-8530; Doria, Alessandra/0000-0002-5381-2649; Sciacca, Crisostomo/0000-0002-8412-4072; Faccini, Riccardo/0000-0003-2613-5141; Filthaut, Frank/0000-0003-3338-2247; Achard, Pablo/0000-0002-4865-3196; Sanchez, Eusebio/0000-0002-9646-8198; Palomares, Carmen/0000-0003-4374-9065; Roth, Stefan/0000-0003-3616-2223; Di Lodovico, Francesca/0000-0003-3952-2175; Longo, Egidio/0000-0001-6238-6787; D'Alessandro, Raffaello/0000-0001-7997-0306; Kirkby, Jasper/0000-0003-2341-9069; Servoli, Leonello/0000-0003-1725-9185; Cerrada, Marcos/0000-0003-0112-1691; Vogel, Helmut/0000-0002-6109-3023; Ferguson, Thomas/0000-0001-5822-3731; Berdugo, Javier/0000-0002-7911-8532 NR 40 TC 47 Z9 47 U1 0 U2 2 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 FEB 4 PY 1999 VL 447 IS 1-2 BP 147 EP 156 DI 10.1016/S0370-2693(98)01552-4 PG 10 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 167XM UT WOS:000078660200020 ER PT J AU Mutz, MW Case, MA Wishart, JF Ghadiri, MR McLendon, GL AF Mutz, MW Case, MA Wishart, JF Ghadiri, MR McLendon, GL TI De novo design of protein function: Predictable structure-function relationships in synthetic redox proteins SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID ELECTRON-TRANSFER; DISTANCE DEPENDENCE; 4-HELIX BUNDLE; DENOVO DESIGN; POLYPEPTIDE; MYOGLOBINS; PEPTIDE C1 Princeton Univ, Dept Chem, Princeton, NJ 08544 USA. Scripps Res Inst, Dept Chem, La Jolla, CA 92037 USA. Scripps Res Inst, Dept Mol Biol, La Jolla, CA 92037 USA. Scripps Res Inst, Skaggs Inst Chem Biol, La Jolla, CA 92037 USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP McLendon, GL (reprint author), Princeton Univ, Dept Chem, Princeton, NJ 08544 USA. EM glm@chemvax.princeton.edu RI Wishart, James/L-6303-2013 OI Wishart, James/0000-0002-0488-7636 NR 25 TC 58 Z9 58 U1 0 U2 12 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD FEB 3 PY 1999 VL 121 IS 4 BP 858 EP 859 DI 10.1021/ja9828612 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 164PB UT WOS:000078471800033 ER PT J AU Liu, Q Yuan, YC Shen, BH Chen, DJ Chen, Y AF Liu, Q Yuan, YC Shen, BH Chen, DJ Chen, Y TI Conformational flexibility of a ubiquitin conjugation enzyme (E2) SO BIOCHEMISTRY LA English DT Article ID N-15 NMR RELAXATION; CELL-CYCLE; CRYSTAL-STRUCTURE; ROTATIONAL DIFFUSION; HUMAN HOMOLOG; YEAST UBC4; CDC34 UBC3; IN-VIVO; PROTEIN; DEGRADATION AB Ubiquitination plays important roles in a variety of biological processes, such as DNA repair, cell cycle regulation, and p53-dependent processes. Despite intensive studies in ubiquitination, the mechanism of substrate recognition is still not well understood. Each E2 has its own substrate specificity, yet substrate proteins recognized by each E2 are highly diverse. To better understand how E2 proteins confer both substrate specificity and diversity, we have studied conformational flexibility of an E2, UBC9, using nuclear magnetic resonance N-15 relaxation and hydrogen-deuterium exchange measurements. Two regions in human UBC9 show higher mobility over a wide range of time scales. Combined with previous biochemical studies, both regions are likely to be important for protein-protein recognition in the ubiquitin pathway. The region near the N-terminus may be important for interactions with the E1-UBL1 conjugate. The region near the C-terminus, which undergoes conformational exchange may be important for substrate binding and catalytic activity. Since E2 enzymes share high homology in primary sequences and three-dimensional structures, the conformational flexibility of UBC9 may represent a general feature of E2 enzymes. This study provides a new perspective for further studies of protein-protein recognition in ubiquitination. C1 Univ Calif Los Alamos Natl Lab, Div Life Sci, DNA Damage & Repair Grp, Los Alamos, NM 87545 USA. City Hope Natl Med Ctr, Beckman Res Inst, Div Immunol, Duarte, CA 91010 USA. City Hope Natl Med Ctr, Beckman Res Inst, Dept Cell & Tumor Biol, Duarte, CA 91010 USA. RP Chen, DJ (reprint author), Univ Calif Los Alamos Natl Lab, Div Life Sci, DNA Damage & Repair Grp, Los Alamos, NM 87545 USA. FU NIGMS NIH HHS [GM54190] NR 48 TC 25 Z9 25 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 FEB 2 PY 1999 VL 38 IS 5 BP 1415 EP 1425 DI 10.1021/bi981840h PG 11 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 170ZF UT WOS:000078836700004 PM 9931006 ER PT J AU Klooster, WT Voss, EJ AF Klooster, WT Voss, EJ TI Structures of 1,3-bis(diphenylphosphino)propane platinum(II) alditolate complexes SO INORGANICA CHIMICA ACTA LA English DT Article DE alditolate complexes; platinum complexes; x-ray diffraction; crystal structures AB Single-crystal X-ray diffraction studies have been carried out on three crystalline (dppp)Pt(II)(alditolate) complexes derived from reactions of the sugar alcohols glycerol, erythritol, and galactitol with (dppp)Ft(CO3). The alditols bind to the platinum via adjacent, deprotonated hydroxyl groups to form a 2,5-dioxaplatinacyclopentane ring system having hydroxyalkyl substituent side-chains. The hydroxyl groups in these side-chains all engage in either intra- or intermolecular hydrogen bonds, the former preferentially involving hydrogen bond donation from a hydroxyl group on the beta-carbon of the metallacycle dihydroxyethyl or trihydroxypropyl substituent to either the near or far metallacycle oxygen atoms to give a six- or seven-membered hydrogen-bonded ring system, respectively. Five-membered hydrogen-bonded ring systems to the adjacent metallacycle oxygen are observed for hydroxymethyl side-chains. These hydrogen-bonded interactions are believed to play a significant role in the complexation regioselectivity observed in these alditolate complexes. Conformations of the 2,5-dioxaplatinacyclopentane ring and dppp chelate ring are also discussed, as are comparisons with other alditolate and diolate structural determinations. (C) Published by Elsevier Science S.A. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Klooster, WT (reprint author), Brookhaven Natl Lab, Dept Chem, POB 5000, Upton, NY 11973 USA. NR 16 TC 4 Z9 4 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0020-1693 J9 INORG CHIM ACTA JI Inorg. Chim. Acta PD FEB 2 PY 1999 VL 285 IS 1 BP 10 EP 17 DI 10.1016/S0020-1693(98)00255-2 PG 8 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 163XD UT WOS:000078431200002 ER PT J AU Johnson, KL Nath, J Pluth, JM Tucker, JD AF Johnson, KL Nath, J Pluth, JM Tucker, JD TI The distribution of chromosome damage, non-reciprocal translocations and clonal aberrations in lymphocytes from Chernobyl clean-up workers SO MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS LA English DT Article DE Chernobyl; chromosome translocation; radiation; clone ID IN-SITU HYBRIDIZATION; HUMAN PERIPHERAL LYMPHOCYTES; STRUCTURAL-ABERRATIONS; BIOLOGICAL DOSIMETRY; IONIZING-RADIATION; GAMMA-RADIATION; EXPOSURE; VITRO; INVOLVEMENT; IRRADIATION AB In this paper we determined whether the frequencies of translocations and insertions are proportional to chromosome size in peripheral blood lymphocytes from Chernobyl nuclear accident clean-up workers and healthy unexposed control subjects. The frequency of aberrations among chromosomes 1, 2 and 4 in both groups was found to be significantly different from the distribution expected on the basis of chromosome size, although the difference was only marginally significant in controls. We also determined whether differences exist in aberration frequencies measured by two scoring systems: the classical method, where reciprocal exchanges are scored as one event, and PAINT, where each break junction is scored asa single event. The two scoring systems gave highly correlated results which yielded an interpretable arithmetic relationship between frequency measurements using the two systems. Approximately 34% of all translocations were observed to be non-reciprocal, and cells bearing clones of abnormal cells were observed in 6 of 198 subjects (3.0%). Our results demonstrate that clones of abnormal cells and the presence of non-reciprocal translocations contribute to the non-proportional distribution of radiation-induced and spontaneous cytogenetic damage. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94551 USA. W Virginia Univ, Genet & Dev Biol Program, Morgantown, WV 26506 USA. RP Tucker, JD (reprint author), Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, POB 808,L-452, Livermore, CA 94551 USA. EM tucker5@llnl.gov FU NCI NIH HHS [O01 CA59431] NR 41 TC 21 Z9 26 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1383-5718 J9 MUTAT RES-GEN TOX EN JI Mutat. Res. Genet. Toxicol. Environ. Mutagen. PD FEB 2 PY 1999 VL 439 IS 1 BP 77 EP 85 DI 10.1016/S1383-5718(98)00177-6 PG 9 WC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology SC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology GA 165FG UT WOS:000078509500008 PM 10029681 ER PT J AU Thomas, CB Nelson, DO Pleshanov, P Vorobstova, I Tureva, L Jensen, R Jones, IM AF Thomas, CB Nelson, DO Pleshanov, P Vorobstova, I Tureva, L Jensen, R Jones, IM TI Elevated frequencies of hypoxanthine phosphoribosyltransferase lymphocyte mutants are detected in Russian liquidators 6 to 10 years after exposure to radiation from the Chernobyl nuclear power plant accident SO MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS LA English DT Article DE Chernobyl; mutation; HPRT; radiation; human population ID ATOMIC-BOMB SURVIVORS; CIRCULATING T-LYMPHOCYTES; NORMAL HUMAN-POPULATION; BREAST-CANCER PATIENTS; INVIVO HPRT MUTATIONS; GLYCOPHORIN-A LOCUS; IONIZING-RADIATION; SOMATIC MUTATIONS; IN-VIVO; CLONING ASSAY AB This study was conducted to determine whether the frequency of hypoxanthine phosphoribosyltransferase (HPRT) deficient lymphocyte mutants would detect an effect of radiation exposure in a population of Russians who were exposed to low levels of radiation while working in 1986 and 1987 as liquidators cleaning up after the Chemobyl nuclear power reactor accident. The HPRT lymphocyte cloning assay was performed on peripheral blood lymphocytes collected between 1992 and 1996 from 142 liquidators and 66 Russian controls, and between 1989 and 1993 from 231 American controls. Russian and American controls were not significantly different for either cloning efficiency or mutant frequency (MF); inclusion of both sets of controls in the analysis increased the ability to detect a Chernobyl exposure effect in the liquidators. After adjusting for age and smoking, the results revealed no significant difference in cloning efficiency of Chernobyl liquidators relative to Russian controls but a significant, 24% increase in liquidator HPRT mutant frequency over Russian controls (90% confidence interval was 7% to 45% increase). The analytical method also accounted for differences in precision of the individual estimates of log CE and log MF and accommodated for outliers. The increase in HPRT mutant frequency of liquidators is an attribute of the exposed population as a whole rather than of individuals. These results demonstrate that, under appropriate circumstances, the HPRT specific locus mutation assay of peripheral blood lymphocytes can be used to detect a semi-acute, low dose radiation exposure of a population, even 6 to 10 years after the exposure. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94550 USA. Minist Publ Hlth Russia, Appl Ecol Res Lab, Moscow, Russia. Minist Publ Hlth Russia, Cent Res Inst Roentgenol & Radiol, St Petersburg, Russia. Tula Diagnost Ctr, Tula, Russia. Univ Calif San Francisco, Dept Lab Med, Ctr Canc, San Francisco, CA 94143 USA. RP Jones, IM (reprint author), Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, POB 808,L-452, Livermore, CA 94550 USA. EM jones20@llnl.gov FU NCI NIH HHS [P01 CA59431] NR 78 TC 14 Z9 17 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1383-5718 J9 MUTAT RES-GEN TOX EN JI Mutat. Res. Genet. Toxicol. Environ. Mutagen. PD FEB 2 PY 1999 VL 439 IS 1 BP 105 EP 119 DI 10.1016/S1383-5718(98)00179-X PG 15 WC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology SC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology GA 165FG UT WOS:000078509500011 PM 10029687 ER PT J AU Ha, TJ Ting, AY Liang, J Caldwell, WB Deniz, AA Chemla, DS Schultz, PG Weiss, S AF Ha, TJ Ting, AY Liang, J Caldwell, WB Deniz, AA Chemla, DS Schultz, PG Weiss, S TI Single-molecule fluorescence spectroscopy of enzyme conformational dynamics and cleavage mechanism SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID RESONANCE ENERGY-TRANSFER; STAPHYLOCOCCAL NUCLEASE; MAGNETIC-RESONANCE; POLARIZATION; RESOLUTION; ACTIN AB Fluorescence resonance energy transfer and fluorescence polarization anisotropy are used to investigate single molecules of the enzyme staphylococcal nuclease. Intramolecular fluorescence resonance energy transfer and fluorescence polarization anisotropy measurements of fluorescently labeled staphylococcal nuclease molecules reveal distinct patterns of fluctuations that may be attributed to protein conformational dynamics on the millisecond time scale. Intermolecular fluorescence resonance energy transfer measurements provide information about the dynamic interactions of staphylococcal nuclease with single substrate molecules. The experimental methods demonstrated here should prove generally useful in studies of protein folding and enzyme catalysis at single-molecule resolution. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA. Univ Calif Berkeley, Howard Hughes Med Inst, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RP Schultz, PG (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Ha, Taekjip/B-9506-2009; weiss, shimon/B-4164-2009 OI Ha, Taekjip/0000-0003-2195-6258; weiss, shimon/0000-0002-0720-5426 FU NIGMS NIH HHS [GM49220] NR 24 TC 366 Z9 374 U1 9 U2 69 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 FEB 2 PY 1999 VL 96 IS 3 BP 893 EP 898 DI 10.1073/pnas.96.3.893 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 164VK UT WOS:000078484100019 PM 9927664 ER PT J AU Srivastava, RC Klooster, WT Koetzle, TF AF Srivastava, RC Klooster, WT Koetzle, TF TI Neutron structures of ammonium tetrafluoroberyllate SO ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE LA English DT Article ID PHASE AB It is thought that hydrogen bonding is responsible for the ferroelectricity in ammonium tetrafluoroberyllate, (NH4)(2)BeF4. In the past X-ray data have been collected, but these did not permit accurate determination of the H-atom positions. In order to obtain more accurate information the neutron structures have now been determined for the paraelectric and ferroelectric phases. Going from the paraelectric to the ferroelectric phase, both the BeF42- and the NH4+ ions rotate and shift from the mirror planes of the paraelectric phase. This results in removal of the mirror-plane symmetry and formation of a superlattice with the a axis doubled. Along the polar c axis, the NH4+ ions move towards the BeF42- ions within chains of molecules and the chains move slightly relative to one another. The rotations and translations give rise to stronger hydrogen-bonding interactions. C1 Indian Inst Technol, Dept Phys, Kanpur 208016, Uttar Pradesh, India. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Srivastava, RC (reprint author), Indian Inst Technol, Dept Phys, Kanpur 208016, Uttar Pradesh, India. EM koetzle@glx.chm.bnl.gov NR 23 TC 13 Z9 13 U1 0 U2 3 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0108-7681 J9 ACTA CRYSTALLOGR B JI Acta Crystallogr. Sect. B-Struct. Sci. PD FEB 1 PY 1999 VL 55 BP 17 EP 23 DI 10.1107/S010876819800737X PN 1 PG 7 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 177NX UT WOS:000079217600003 ER PT J AU Terwilliger, TC Berendzen, J AF Terwilliger, TC Berendzen, J TI Discrimination of solvent from protein regions in native Fouriers as a means of evaluating heavy-atom solutions in the MIR and MAD methods SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article ID MACROMOLECULAR CRYSTALLOGRAPHY; RESOLUTION AB An automated examination of the native Fourier is tested as a means of evaluation of a heavy-atom solution in MAD and MIR methods for macromolecular crystallography. It is found that the presence of distinct regions of high and low density variation in electron-density maps is a good indicator of the correctness of a heavy-atom solution in the MIR and MAD methods. The method can be used to evaluate heavy-atom solutions during MAD and MIR structure solutions and to determine the handedness of the structure if anomalous data have been measured. C1 Univ Calif Los Alamos Natl Lab, Struct Biol Grp, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Biophys Grp, Los Alamos, NM 87545 USA. RP Terwilliger, TC (reprint author), Univ Calif Los Alamos Natl Lab, Struct Biol Grp, Mail Stop M888, Los Alamos, NM 87545 USA. RI Terwilliger, Thomas/K-4109-2012 OI Terwilliger, Thomas/0000-0001-6384-0320 NR 11 TC 50 Z9 50 U1 0 U2 0 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0907-4449 J9 ACTA CRYSTALLOGR D JI Acta Crystallogr. Sect. D-Biol. Crystallogr. PD FEB PY 1999 VL 55 BP 501 EP 505 DI 10.1107/S0907444998012657 PN 2 PG 5 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 165UU UT WOS:000078540900020 PM 10089362 ER PT J AU Odyniec, G AF Odyniec, G TI Statistical and dynamical fluctuations in heavy ion collisions: Role of conservation laws in event-by-event analysis SO ACTA PHYSICA POLONICA B LA English DT Article AB The analysis of the statistical and dynamical fluctuations in nucleus-nucleus collisions on an event-by-event basis strongly relies on a comparison with specially constructed artificial events where statistical fluctuations and kinematical correlations are under control. In this paper, we present a novel, analytical method of constructing reference events based on independent emission, modified by the energy/momentum constraint, which can lead to a better understanding of the nature of the observed final-state fluctuations. This approach can be easily used in the analysis of other topics in the heavy ion field (e.g. flow, HBT etc.) allowing more precise measurements. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Odyniec, G (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 6 TC 5 Z9 5 U1 0 U2 0 PU ACTA PHYSICA POLONICA B, JAGELLONIAN UNIV, INST PHYSICS PI KRAKOW PA REYMONTA 4, 30-059 KRAKOW, POLAND SN 0587-4254 J9 ACTA PHYS POL B JI Acta Phys. Pol. B PD FEB PY 1999 VL 30 IS 2 BP 385 EP 391 PG 7 WC Physics, Multidisciplinary SC Physics GA 175CL UT WOS:000079074600011 ER PT J AU Hamilton, JH Ramayya, AV Hwang, JK Greiner, W Zhu, SJ Sandulescu, A Floresscu, A Kormicki, J Ter-Akopian, G Oganessian, Y Daniel, AV Popeko, GS Kliman, J Morhac, M Cole, JD Aryaeinejad, R Drigert, MW Collins, WE Ma, WC Jones, EF Peker, LK Gore, PM Drafta, G Babu, BRS Wang, G Deng, JK AF Hamilton, JH Ramayya, AV Hwang, JK Greiner, W Zhu, SJ Sandulescu, A Floresscu, A Kormicki, J Ter-Akopian, G Oganessian, Y Daniel, AV Popeko, GS Kliman, J Morhac, M Cole, JD Aryaeinejad, R Drigert, MW Collins, WE Ma, WC Jones, EF Peker, LK Gore, PM Drafta, G Babu, BRS Wang, G Deng, JK TI Cold spontaneous fission processes of Cf-252 and the structure of neutron rich Ba and La nuclei SO ACTA PHYSICA SLOVACA LA English DT Article ID OCTUPOLE DEFORMATION; BARIUM ISOTOPES; EMISSION; MASS AB Rare cold (zero neutron emission and low excitation energy) binary fission, cold alpha and Be-10-accompanied ternary fission and cold fission with two neutrons emitted at scission and new nuclear structure effects have been observed in the spontaneous fission of Cf-252. Evidence for stable octupole deformation in Ba-143,Ba-144,Ba-146 and La-145,La-147 are presented. The roles of rotation in both enhancing and quenching stable octupole deformation are observed. In La-145 one has a new class of shape coexistence with symmetric and asymmetric rotational bands. C1 Vanderbilt Univ, Dept Phys, Nashville, TN 37235 USA. Univ Frankfurt, Inst Theoret Phys, D-6000 Frankfurt, Germany. Joint Inst Heavy Ion Res, Oak Ridge, TN 37831 USA. Tsing Hua Univ, Dept Phys, Beijing 100084, Peoples R China. Joint Inst Nucl Res, Dubna 141980, Russia. Slovak Acad Sci, Inst Phys, Bratislava 84228, Slovakia. Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. Fisk Univ, Dept Phys, Nashville, TN 37208 USA. Mississippi State Univ, Dept Phys, Mississippi State, MS 39762 USA. RP Hamilton, JH (reprint author), Vanderbilt Univ, Dept Phys, Nashville, TN 37235 USA. NR 29 TC 10 Z9 10 U1 0 U2 0 PU SLOVAK ACAD SCIENCES INST PHYSICS PI BRATISLAVA PA DUBRAVSKA CESTA 9, 842 28 BRATISLAVA, SLOVAKIA SN 0323-0465 J9 ACTA PHYS SLOVACA JI Acta Phys. Slovaca PD FEB PY 1999 VL 49 IS 1 BP 31 EP 42 PG 12 WC Physics, Multidisciplinary SC Physics GA 183NC UT WOS:000079558800003 ER PT J AU Pereyra, R Zukas, E AF Pereyra, R Zukas, E TI Jacquet-Lucas Award winner - Transformation behavior of cerium SO ADVANCED MATERIALS & PROCESSES LA English DT Article AB The Jacquet-Lucas Award is given each year to the winner of the IMS/ASM Metallographic Contest. It consists of a gold medal and $3000 conferred by IMS, an Affiliate Society of ASM International, for the microstructural analysis entry showing the highest level of technical expertise. C1 Univ Calif Los Alamos Natl Lab, Div Nucl Mat Technol, Los Alamos, NM 87545 USA. RP Pereyra, R (reprint author), Univ Calif Los Alamos Natl Lab, Div Nucl Mat Technol, Mail Stop G730, Los Alamos, NM 87545 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 0026-0665 J9 ADV MATER PROCESS JI Adv. Mater. Process. PD FEB PY 1999 VL 155 IS 2 BP 29 EP 32 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA 164FR UT WOS:000078453000003 ER PT J AU Cheng, YS Barr, EB Fan, BJ Hargis, PJ Rader, DJ O'Hern, TJ Torczynski, JR Tisone, GC Preppernau, BL Young, SA Radloff, RJ AF Cheng, YS Barr, EB Fan, BJ Hargis, PJ Rader, DJ O'Hern, TJ Torczynski, JR Tisone, GC Preppernau, BL Young, SA Radloff, RJ TI Detection of bioaerosols using multiwavelength UV fluorescence spectroscopy SO AEROSOL SCIENCE AND TECHNOLOGY LA English DT Article ID AERODYNAMIC PARTICLE SIZER; PERFORMANCE; DESIGN AB This article describes the development of an aerosol generation apparatus to investigate the fluorescence spectra of bioaerosols, The experimental system was set up in a Biosafety Level II Laboratory, The system included an aerosol generator, chamber, aerosol monitoring instrumentation, and laser-induced-fluorescence detection system. The aerosol generators, chamber, and monitors were housed in an enclosure with the exhaust vented through a double HEPA filtration system. A Hospitak nebulizer using aqueous suspensions generated aerosols of bacteria. Aerosols of pollens mere generated using a small-scale dry powder generator. The aerosol chamber, with four windows for optical access, was designed with the aid of a computational fluid dynamics code to optimize the generation of aerosol beams with a well-defined geometry for reproducible fluorescence measurements. Aerosol concentrations and aerodynamic diameters in the chamber were determined using a biter, an impinger, a modified Andersen impactor, and an Aerodynamic Particle Sizer. Geometric size and particle shapes were determined using microscopy and imaging analysis. The well-characterized aerosol stream allowed reproducible fluorescence measurements to be made with the aerosol generation methods developed in this work. Fluorescence spectra of four bacteria, Escherichia coli, Staphylococcus aureus, Bacillus subtilis var niger, and Bacillus thuringiensis, were found to be very similar. Calibrations of the fluorescence instrumentation allowed cross sections of live cells, killed cells, and spores to be measured with an uncertainty of about 2 to 5. C1 Lovelace Resp Res Inst, Albuquerque, NM 87185 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ New Mexico, Dept Microbiol, Albuquerque, NM 87131 USA. RP Cheng, YS (reprint author), Lovelace Resp Res Inst, POB 5890, Albuquerque, NM 87185 USA. NR 15 TC 64 Z9 65 U1 1 U2 16 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA SN 0278-6826 J9 AEROSOL SCI TECH JI Aerosol Sci. Technol. PD FEB PY 1999 VL 30 IS 2 BP 186 EP 201 DI 10.1080/027868299304778 PG 16 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 171ME UT WOS:000078866900009 ER PT J AU Benson, J Reis, V AF Benson, J Reis, V TI Conversations with Victor Reis SO AEROSPACE AMERICA LA English DT Editorial Material C1 US DOE, Def Programs, Washington, DC 20585 USA. RP Benson, J (reprint author), US DOE, Def Programs, Washington, DC 20585 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0740-722X J9 AEROSPACE AM JI Aerosp. Am. PD FEB PY 1999 VL 37 IS 2 BP 14 EP 16 PG 3 WC Engineering, Aerospace SC Engineering GA 165LE UT WOS:000078521600006 ER PT J AU Li, SG Jin, WQ Huang, P Xu, NP Shi, J Hu, MZC Payzant, EA Ma, YH AF Li, SG Jin, WQ Huang, P Xu, NP Shi, J Hu, MZC Payzant, EA Ma, YH TI Perovskite-related ZrO2-doped SrCo0.4Fe0.6O3-delta membrane for oxygen permeation SO AICHE JOURNAL LA English DT Article ID CERAMIC MEMBRANES; PARTIAL OXIDATION; BRITTLE MATERIALS; METHANE; REACTORS; TRANSFORMATION; PERMEABILITY; TRANSPORT; SYNGAS; FLUX AB A typical perovskite La0.2Sr0.8Co0.2Fe0.8O3-delta (LSCF) membrane and a novel perovskite-related ZrO2-doped SrCo0.4Fe0.6O3-delta (SCFZ) membrane were successfully prepared. The sintered membranes were characterized by an in-situ high-temperature X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. Oxygen permeabilities of the two dense membranes were measured in the temperature range of 923 to 1,173 K under a fixed oxygen partial pressure gradient. The results of the oxygen permeation experiment and high-temperature X-ra diffraction in argon atmosphere indicate that the perovskite-related SCFZ membrane has higher oxygen fluxes and is stable than that of the LSCF membrane at elevated temperatures and reduced oxygen partial pressures. C1 Nanjing Univ Chem Technol, Membrane Sci & Technol Res Ctr, Nanjing 210009, Peoples R China. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. Worcester Polytech Inst, Dept Chem Engn, Ctr Inorgan Membrane Studies, Worcester, MA 01609 USA. RP Xu, NP (reprint author), Nanjing Univ Chem Technol, Membrane Sci & Technol Res Ctr, Nanjing 210009, Peoples R China. RI Payzant, Edward/B-5449-2009; Jin, Wanqin/L-6011-2013 OI Payzant, Edward/0000-0002-3447-2060; NR 36 TC 50 Z9 55 U1 3 U2 23 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0001-1541 J9 AICHE J JI AICHE J. PD FEB PY 1999 VL 45 IS 2 BP 276 EP 284 DI 10.1002/aic.690450208 PG 9 WC Engineering, Chemical SC Engineering GA 169GY UT WOS:000078740300007 ER PT J AU Foster, NS Autrey, ST Amonette, JE Small, JR Small, EW AF Foster, NS Autrey, ST Amonette, JE Small, JR Small, EW TI Laser photoacoustic spectroscopy: A versatile absorption-spectroscopic technique SO AMERICAN LABORATORY LA English DT Article ID INDUCED OPTOACOUSTIC SPECTROSCOPY; H BOND STRENGTHS; ELECTRON-TRANSFER; CALORIMETRY; VOLUME; WATER; FLUORESCENCE; PORPHYRIN; PROTEINS; ENERGY AB The versatility of laser photoacoustic spectroscopy (LPAS) stems from the many processes that give rise to volumetric changes after photoexcitation of a sample. This article provides a concise review of the technology and its applications. C1 Pacific NW Lab, Richland, WA 99352 USA. Eastern Washington Univ, Cheney, WA 99004 USA. Quantum NW Inc, Spokane, WA USA. RP Foster, NS (reprint author), Pacific NW Lab, POB 999 MS K8-96, Richland, WA 99352 USA. NR 35 TC 5 Z9 5 U1 0 U2 1 PU INT SCIENTIFIC COMMUN INC PI SHELTON PA PO BOX 870, 30 CONTROLS DRIVE, SHELTON, CT 06484-0870 USA SN 0044-7749 J9 AM LAB JI Am. Lab. PD FEB PY 1999 VL 31 IS 4 BP 96S EP + PG 9 WC Chemistry, Analytical; Instruments & Instrumentation SC Chemistry; Instruments & Instrumentation GA 170BP UT WOS:000078785800013 ER PT J AU Grate, JW Fadeff, SK Egorov, O AF Grate, JW Fadeff, SK Egorov, O TI Separation-optimized sequential injection method for rapid automated analytical separation of Sr-90 in nuclear waste SO ANALYST LA English DT Article ID PLASMA-MASS SPECTROMETRY; PRECONCENTRATION; RADIONUCLIDES; STRONTIUM; URANIUM; SAMPLES; SR-89 AB An automated sequential injection (ST) analyzer was developed for analytical separations of Sr-90 in nuclear waste samples. The system provides rapid separation of Sr-90 from matrix and potential interfering elements using an Sr-selective extraction chromatographic column. After separation, Sr-90 activity can be determined by either on-line radiometric detection or off-line counting of collected fractions. The separation was investigated under automated conditions. Eluent compositions were determined that provide consistent, high, reproducible recoveries of Sr from the separation column. Procedures were designed with emphasis on rapid sample throughput. Using fraction collection, a set of eight samples can be processed in just over 1 h. Using on-line detection, each sample is separated and quantified in 22 min. The method was applied to nuclear waste supernate and Vitrified nuclear waste. C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Pacific NW Lab, Radiochem Proc Grp, Richland, WA 99352 USA. RP Grate, JW (reprint author), Pacific NW Lab, Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. NR 17 TC 26 Z9 27 U1 0 U2 4 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD,, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND SN 0003-2654 J9 ANALYST JI Analyst PD FEB PY 1999 VL 124 IS 2 BP 203 EP 210 DI 10.1039/a807468b PG 8 WC Chemistry, Analytical SC Chemistry GA 167VF UT WOS:000078653800020 ER PT J AU Barshick, SA Wolf, DA Vass, AA AF Barshick, SA Wolf, DA Vass, AA TI Differentiation of microorganisms based on pyrolysis ion trap mass spectrometry using chemical ionization SO ANALYTICAL CHEMISTRY LA English DT Article ID GAS-CHROMATOGRAPHY; METHYLATION; LIPIDS; ACIDS AB The ability to differentiate microorganisms using pyrolysis-ion trap mass spectrometry was demonstrated for five Gram-negative disease-causing organisms: Brucella melitensis, Brucella suis, Vibrio cholera, Yersinia pestis, and Francisella tularensis, Bacterial profiles were generated for gamma-irradiated bacterial samples using pyrolytic methylation and compared for electron ionization and chemical ionization using several liquid reagents with increasing proton affinities. Electron ionization combined with pyrolysis caused extensive fragmentation, resulting in a high abundance of lower mass ions and diminishing the diagnostic value of the technique for compound identification and bacterial profiling. Chemical ionization reduced the amount of fragmentation due to ionization while enhancing the molecular ion region of the fatty acids. As the proton affinity of the reagent increased, the protonated molecular ions of the fatty acids became the predominant ions observed in the mass spectrum. As a result, chemical ionization was shown to be more effective than electron ionization in bacterial profiling. Whereas the bacteria could be distinguished at the Genera level using electron ionization, further differentiation to the subspecies level was possible using chemical ionization. The greatest separation among the five test organisms, in terms of Euclidean distances, was obtained using ethanol as the chemical ionization reagent and using pooled masses representing specific fatty acid biomarkers rather than total ion profiles. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Barshick, SA (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA. EM barshicks@ornl.gov NR 31 TC 35 Z9 36 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 FEB 1 PY 1999 VL 71 IS 3 BP 633 EP 641 DI 10.1021/ac980356h PG 9 WC Chemistry, Analytical SC Chemistry GA 163VA UT WOS:000078426000021 PM 9989380 ER PT J AU Spriggs, GD Busch, RD Sakurai, T Okajima, S AF Spriggs, GD Busch, RD Sakurai, T Okajima, S TI The equivalent fundamental-mode source SO ANNALS OF NUCLEAR ENERGY LA English DT Article ID FISSION AB In this work, we describe the concept of an equivalent fundamental-mode source, and we derive an expression for a factor, g*, that converts any arbitrary source distribution to its equivalent fundamental-mode source strength. We also present a new experimental method that can be employed to measure the equivalent fundamental-mode source strength in a multiplying assembly. We demonstrate the method on the zero-power, XIX-1 assembly at the Fast-Critical Assembly (FCA) Facility, Japan Atomic Energy Research Institute (JAERI). (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ New Mexico, Dept Chem & Nucl Engn, Albuquerque, NM 87131 USA. Japan Atom Energy Res Inst, Tokai, Ibaraki 31911, Japan. RP Spriggs, GD (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663,MS D409, Los Alamos, NM 87545 USA. NR 25 TC 9 Z9 12 U1 0 U2 0 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 FEB PY 1999 VL 26 IS 3 BP 237 EP 264 DI 10.1016/S0306-4549(98)00048-6 PG 28 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 149MY UT WOS:000077610300004 ER PT J AU Barrett, CL Reidys, CM AF Barrett, CL Reidys, CM TI Elements of a theory of computer simulation - I: Sequential CA over random graphs SO APPLIED MATHEMATICS AND COMPUTATION LA English DT Article DE computer simulation; random graph; connectivity; components; update graph; sequential CA ID COMPUTATION AB This paper is a first step in the development of mathematical foundations for a theory of simulation. We employ sequentially updated cellular automata (sCA) over arbitrary graphs as a paradigmatic framework, In the development of the theory, we focus on the properties of causal dependencies among local mappings in a simulation. Let Y be a graph in which (a) each vertex i has a state x(i) is an element of {0,1} and (b) there exists a local map f(i) defined on the states of the Y-neighbors and x(i) that returns the state of y(i) is an element of {0, 1}. Suppose {i(l),..,, i(n)} is a permutation of the Y-vertices, then the order of application of the local maps fi, induces a sequential (or asynchronous) cellular automaton (sCA) over Y. In this paper we introduce a mapping between the base graph Y, over which the sCA is defined and which represents the mutual dependencies of the local maps, and the update graph U(Y), whose vertices are permutations of all Y-vertices. Two permutations nl, nz are adjacent in U(Y) if they differ in exactly two consecutive coordinates, {i(k), i(k+1)} and {i(k), i(k+1)} is not an element of eY. U(Y) represents a conceptual framework which allows to determine equivalence classes of sCA for a given graph X, independent of the family of local maps (f(i))(1 less than or equal to i less than or equal to n). We consider: (a) U as a random variable over G(n,p) and analyze the induced random graph U(G(n,p)), the update graph, and show (b) that U exhibits properties of a covariant functor. (C) 1999 Published by Elsevier Science Inc. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, TSADOSA, Los Alamos, NM 87548 USA. RP Barrett, CL (reprint author), Univ Calif Los Alamos Natl Lab, TSADOSA, Mailstop TA-0,SM-1237,MS M997, Los Alamos, NM 87548 USA. NR 26 TC 47 Z9 47 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0096-3003 J9 APPL MATH COMPUT JI Appl. Math. Comput. PD FEB PY 1999 VL 98 IS 2-3 BP 241 EP 259 DI 10.1016/S0096-3003(97)10166-7 PG 19 WC Mathematics, Applied SC Mathematics GA 144WQ UT WOS:000077339000011 ER PT J AU Roth, EG Holland, OW Thomas, DK AF Roth, EG Holland, OW Thomas, DK TI Control of diffusion of implanted boron in preamorphized Si: Elimination of interstitial defects at the amorphous-crystal interface SO APPLIED PHYSICS LETTERS LA English DT Article ID ENHANCED DIFFUSION; ION-IMPLANTATION; POINT-DEFECT; SILICON; DAMAGE; TEMPERATURE; ENERGY; ALLOYS AB Transient-enhanced diffusion (TED) during thermal annealing of ion-implanted B in Si is well established and attributed to the ion-induced, excess interstitials. On the other hand, the mechanism to account for TED of B in preamorphized (PA) Si remains unclear. Enhanced diffusion of the B persists in regrown layers even though the ion-induced interstitial defects responsible for TED in B+-only implanted Si are eliminated following regrowth. To test the hypothesis that TED in PA Si results from the "excess'' interstitial-type defects below the amorphous-crystalline (a-c) interface, a buried PA layer has been recrystallized from the surface inward to the SiO2 interface of silicon-on-insulator material to eliminate all possible sources of excess interstitials. The effect on B diffusion and the role of the residual interstitial-type defects will be discussed. (C) 1999 American Institute of Physics. [S0003-6951(99)03904-2]. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ N Texas, Dept Phys, Denton, TX 76203 USA. RP Roth, EG (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. NR 22 TC 1 Z9 1 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 1 PY 1999 VL 74 IS 5 BP 679 EP 681 DI 10.1063/1.122985 PG 3 WC Physics, Applied SC Physics GA 163AG UT WOS:000078379600016 ER PT J AU Meldrum, A Zuhr, RA Sonder, E Budai, JD White, CW Boatner, LA Ewing, RC Henderson, DO AF Meldrum, A Zuhr, RA Sonder, E Budai, JD White, CW Boatner, LA Ewing, RC Henderson, DO TI Formation of oriented particles in an amorphous host: ZnS nanocrystals in silicon SO APPLIED PHYSICS LETTERS LA English DT Article ID SEMICONDUCTOR AB Processes for incorporating randomly oriented crystalline precipitates in an amorphous host can be traced back to the 17th century when Cassius produced "gold ruby'' glass. In this glass, octahedral colloidal precipitates of gold scatter light by the Mie process to produce a deep red color. In contrast to gold ruby glass, we describe a type of material in which the crystalline precipitates are crystallographically aligned in a coherent manner-even though they are dispersed in an amorphous matrix. Ion implantation and thermal processing are first used to form zinc sulfide nanocrystals that are coherently oriented with respect to a crystalline Si host. The Si is then amorphized by ion irradiation leaving the highly radiation-resistant ZnS precipitates in an aligned crystalline state. The process is anticipated to find applications in the creation of surfaces with unique optoelectronic properties. (C) 1999 American Institute of Physics. [S0003-6951(99)02905-8]. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ Michigan, Dept NE&RS, Ann Arbor, MI 48109 USA. Fisk Univ, Dept Phys, Nashville, TN 37208 USA. RP Meldrum, A (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. RI Boatner, Lynn/I-6428-2013; Budai, John/R-9276-2016 OI Boatner, Lynn/0000-0002-0235-7594; Budai, John/0000-0002-7444-1306 NR 12 TC 12 Z9 12 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 1 PY 1999 VL 74 IS 5 BP 697 EP 699 DI 10.1063/1.122991 PG 3 WC Physics, Applied SC Physics GA 163AG UT WOS:000078379600022 ER PT J AU Smith, S Cheong, HM Fluegel, BD Geisz, JF Olson, JM Kazmerski, LL Mascarenhas, A AF Smith, S Cheong, HM Fluegel, BD Geisz, JF Olson, JM Kazmerski, LL Mascarenhas, A TI Spatially resolved photoluminescence in partially ordered GaInP2 SO APPLIED PHYSICS LETTERS LA English DT Article AB Scanning confocal microscopy combined with high-resolution spectroscopy is used to probe the spatial variations in the low-temperature (5.0 K) photoluminescence (PL) of partially ordered GaInP2 with a spatial resolution of 0.7 mu m. We observe large regions (1-2 mu m) wherein the excitonic PL is suppressed up to a factor of four ("defect- rich" regions) when compared to unaffected areas. These defect-rich regions show a commensurate enhancement in the lower energy below gap emission. The spatial extent of this effect is inconsistent with the picture that the low-energy emission originates solely at the antiphase boundaries of the ordered domains and therefore must originate from other defects within the ordered domain as well. (C) 1999 American Institute of Physics. [S0003-6951(99)02005-7]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Smith, S (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Cheong, Hyeonsik/D-7424-2012 OI Cheong, Hyeonsik/0000-0002-2347-4044 NR 12 TC 17 Z9 17 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 1 PY 1999 VL 74 IS 5 BP 706 EP 708 DI 10.1063/1.123189 PG 3 WC Physics, Applied SC Physics GA 163AG UT WOS:000078379600025 ER PT J AU Kurtz, SR Allerman, AA Jones, ED Gee, JM Banas, JJ Hammons, BE AF Kurtz, SR Allerman, AA Jones, ED Gee, JM Banas, JJ Hammons, BE TI InGaAsN solar cells with 1.0 eV band gap, lattice matched to GaAs SO APPLIED PHYSICS LETTERS LA English DT Article AB The design, growth by metalorganic chemical vapor deposition, and processing of an In0.07Ga0.93As0.98N0.02 solar cell, with 1.0 eV band gap, lattice matched to GaAs is described. The hole diffusion length in annealed, n-type InGaAsN is 0.6- 0.8 mu m, and solar cell internal quantum efficiencies >70% are obtained. Optical studies indicate that defects or impurities, from InGaAsN doping and nitrogen incorporation, limit solar cell performance. (C) 1999 American Institute of Physics. [S0003-6951(99)01805-7]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Kurtz, SR (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 8 TC 457 Z9 464 U1 5 U2 47 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 1 PY 1999 VL 74 IS 5 BP 729 EP 731 DI 10.1063/1.123105 PG 3 WC Physics, Applied SC Physics GA 163AG UT WOS:000078379600033 ER PT J AU Rokhinson, LP Chen, CJ Tsui, DC Vawter, GA Choi, KK AF Rokhinson, LP Chen, CJ Tsui, DC Vawter, GA Choi, KK TI Quantum grid infrared photodetectors SO APPLIED PHYSICS LETTERS LA English DT Article ID GRATING COUPLER; WAVE-GUIDE; EFFICIENCY; GAAS AB In this letter we introduce a quantum well infrared photodetector (QWIP) structure, which we refer to as the quantum grid infrared photodetector (QGIP). In an ideal structure, a grid pattern with very narrow linewidth is created in the QWIP active region to achieve lateral electron confinement, thereby improving its absorption as well as transport characteristics. In order to realize this detector structure, we have fabricated QGIPs with line patterns of lithographical linewidths w(l) ranging from 0.1 to 4 mu m, allowing for possible sidewall depletion. Low-damage reactive ion beam etching was employed to produce vertical sidewalls. From the experimental data, although the best detector performance occurs at w(l)approximate to 1.5 mu m, the detector starts to improve when w(l)<0.5 mu m, indicating a possible quantum confinement effect. (C) 1999 American Institute of Physics. [S0003-6951(99)04005-X]. C1 Princeton Univ, Dept Elect Engn, Princeton, NJ 08544 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. USA, Res Lab, Adelphi, MD 20783 USA. RP Rokhinson, LP (reprint author), Princeton Univ, Dept Elect Engn, Princeton, NJ 08544 USA. EM leonid@ee.princeton.edu RI Choi, Kwong-Kit/K-9205-2013 NR 10 TC 10 Z9 10 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 1 PY 1999 VL 74 IS 5 BP 759 EP 761 DI 10.1063/1.123302 PG 3 WC Physics, Applied SC Physics GA 163AG UT WOS:000078379600043 ER PT J AU Shultis, JK Khan, F Letellier, B Faw, RE AF Shultis, JK Khan, F Letellier, B Faw, RE TI Determining soil contamination profiles from intensities of capture-gamma rays using above-surface neutron sources SO APPLIED RADIATION AND ISOTOPES LA English DT Article ID IMAGE AB Four methods are presented to estimate contaminant concentration profiles in soil from the intensities of neutron-induced capture-gamma photon intensities measured at the soil surface. In particular, the method of linear regularization with and without an iterative positivity constraint, the Backus-Gilbert method, and the maximum entropy method are applied to the soil contamination problem. Example results obtained with the four methods are given for photon intensities calculated for idealized test contaminant profiles in soil irradiated by neutron sources above the surface. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Kansas State Univ, Dept Mech & Nucl Engn, Manhattan, KS 66506 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. RP Shultis, JK (reprint author), Kansas State Univ, Dept Mech & Nucl Engn, Manhattan, KS 66506 USA. NR 23 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 0969-8043 J9 APPL RADIAT ISOTOPES JI Appl. Radiat. Isot. PD FEB PY 1999 VL 50 IS 2 BP 415 EP 433 DI 10.1016/S0969-8043(98)00012-8 PG 19 WC Chemistry, Inorganic & Nuclear; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Chemistry; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 166AY UT WOS:000078555100020 PM 10081144 ER PT J AU Ma, Q Rosenberg, RA AF Ma, Q Rosenberg, RA TI Core and valence level characterization of the interfacial reaction between partially oxidized Ti films and graphite SO APPLIED SURFACE SCIENCE LA English DT Article DE core; valence level characterization; interfacial reaction; partially oxidized Ti films; graphite ID X-RAY PHOTOEMISSION; ELECTRONIC-STRUCTURE; MATRIX COMPOSITES; CARBON; FIBER; TRANSITION; SURFACE; IDENTIFICATION; SPECTROSCOPY; OXIDATION AB The solid state reaction between partially oxidized Ti films and highly oriented pyrolitic graphite (HOPG) was studied by soft X-ray photoelectron spectroscopy (PES). The reaction readily occurs upon room-temperature deposition, and is apparently catalyzed by the presence of oxide species. The interfacial reaction is also characterized by its influence on the surface electronic structure of HOPG through modification of the C 1s core-hole screening process. The characteristics of the electronic structures of the films and the interface are described by analysis of the valence band photoemission spectra. An electron-transfer model, previously suggested by the other workers, may be used to describe this catalytical reaction. (C) 1999 Published by Elsevier Science B.V. 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. EM qingma@aps.anl.gov RI Rosenberg, Richard/K-3442-2012 NR 38 TC 7 Z9 7 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD FEB PY 1999 VL 140 IS 1-2 BP 83 EP 89 DI 10.1016/S0169-4332(98)00477-2 PG 7 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA 166LB UT WOS:000078576900011 ER PT J AU Nelson, AJ Gregoratti, L Chagarov, E Lonza, D Marsi, M Kiskinova, M AF Nelson, AJ Gregoratti, L Chagarov, E Lonza, D Marsi, M Kiskinova, M TI X-ray photoemission analysis of CS2 treated polycrystalline Cu(In,Ga)Se-2 SO APPLIED SURFACE SCIENCE LA English DT Article DE polycrystalline; thin film; scanning electron microscopy ID GAAS-SURFACES; SULFUR PASSIVATION; ESCA MICROSCOPY; CUINSE2; EFFICIENCY; ELETTRA AB Device-grade polycrystalline thin-film Cu(Tn(0.5)Ga(0.5))Se-2 was treated with CS2 to determine the resulting microscopic surface composition/morphology. Scanning electron microscopy (SEM) was used to evaluate the resultant surface morphology. Angle-integrated high-resolution photoemission measurements on the valence band (Cu 3d) electronic structure and In 4d/Ga 3d, Se 3d and S 2p core lines were used to evaluate the chemistry of the CS2 treated surface. Results show that the surface has been planarized by the highly reactive CS2 treatment and that S has been incorporated at the surface, possibly creating a wider bandgap Cu(In1-xGax)(Se1-ySy)(2) surface layer. The purpose of this investigation is to find an environmentally safe replacement for the toxic CdS overlayer commonly used for heterojunction devices without sacrificing overall device performance and reliability. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Sincrotrone Trieste, I-34012 Trieste, Italy. RP Nelson, AJ (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 19 TC 3 Z9 3 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD FEB PY 1999 VL 140 IS 1-2 BP 208 EP 214 DI 10.1016/S0169-4332(98)00597-2 PG 7 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA 166LB UT WOS:000078576900028 ER PT J AU Adan-Bayewitz, D Asaro, F Giauque, RD AF Adan-Bayewitz, D Asaro, F Giauque, RD TI Determining pottery provenance: Application of a new high-precision x-ray fluorescence method and comparison with instrumental neutron activation analysis SO ARCHAEOMETRY LA English DT Article DE Israel; Galilee; Roman; high-precision x-ray fluorescence; instrumental neutron activation analysis; principal component analysis; ceramics; provenance C1 Bar Ilan Univ, Dept Land Israel Studies, IL-52100 Ramat Gan, Israel. EO Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Adan-Bayewitz, D (reprint author), Bar Ilan Univ, Dept Land Israel Studies, IL-52100 Ramat Gan, Israel. NR 41 TC 22 Z9 23 U1 0 U2 1 PU OXFORD UNIV PI OXFORD PA RES LAB ARCHAEOL HIST ART 6 KEBLE RD, OXFORD, ENGLAND OX1 3QJ SN 0003-813X J9 ARCHAEOMETRY JI Archaeometry PD FEB PY 1999 VL 41 BP 1 EP 24 DI 10.1111/j.1475-4754.1999.tb00849.x PN 1 PG 24 WC Archaeology; Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Geosciences, Multidisciplinary SC Archaeology; Chemistry; Geology GA 174LC UT WOS:000079035800001 ER PT J AU Alkorta, I Park, C Kong, J Garbisu, C Alberti, M Pon, N Hearst, JE AF Alkorta, I Park, C Kong, J Garbisu, C Alberti, M Pon, N Hearst, JE TI Rhodobacter capsulatus DNA topoisomerase I purification and characterization SO ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS LA English DT Article DE DNA topology; DNA topoisomerase I; Rhodobacter capsulatus; purple bacterium ID ESCHERICHIA-COLI; RHODOPSEUDOMONAS-CAPSULATA; METHANOPYRUS-KANDLERI; GENE-EXPRESSION; PEA CHLOROPLAST; REVERSE GYRASE; CALF THYMUS; PROTEIN; ENZYME; CELLS AB A 30-kDa DNA topoisomerase has been purified to near homogeneity from the purple nonsulfur photosynthetic bacterium Rhodobacter capsulatus. The enzyme is recognized by an antibody against a 16-mer peptide sequence from human DNA topoisomerase I. The purified enzyme is a type I topoisomerase. Consistent with the properties of other prokaryotic type I DNA topoisomerases, the isolated enzyme is unable to relax positively supercoiled DNA and absolutely requires divalent cations for its relaxation activity. However, regardless of the Mg+2 concentrations, ATP concentrations above 5 mM completely inhibit the relaxing activity. The enzyme is sensitive to high salt concentrations and the optimal activity occurs at salt concentrations between 3 and 30 mM for monovalent cations. Single-stranded M13 DNA is a strong inhibitor of this relaxing activity. The enzyme is inhibited by ethidium bromide, confirming that this DNA topoisomerase is incapable of relaxing positive supercoils. Topoisomerase I-specific inhibitors like Hoechst 32258 and actinomycin D inhibit the enzymatic activity while the enzyme is resistant to type II topoisomerase inhibitors such as norfloxacin, nalidixic acid, and novobiocin. From these enzymatic characteristics, we conclude that the R. capsulatus DNA topoisomerase is a prokaryotic type I DNA topoisomerase. (C) 1999 Academic Press. C1 Univ Basque Country, Fac Ciencias, Dept Bioquim & Biol Mol, E-48080 Bilbao, Spain. Lawrence Berkeley Lab, Struct Biol Div, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Alkorta, I (reprint author), Univ Basque Country, Fac Ciencias, Dept Bioquim & Biol Mol, Apdo 644, E-48080 Bilbao, Spain. EM gbzalcai@lg.ehu.es RI Garbisu, Carlos/D-1942-2012; Garbisu, Carlos/G-1908-2014; Alkorta, Itziar/N-4374-2014 OI Garbisu, Carlos/0000-0002-5577-6151; Alkorta, Itziar/0000-0002-1976-8904 NR 46 TC 4 Z9 4 U1 0 U2 1 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0003-9861 J9 ARCH BIOCHEM BIOPHYS JI Arch. Biochem. Biophys. PD FEB 1 PY 1999 VL 362 IS 1 BP 123 EP 130 DI 10.1006/abbi.1998.1023 PG 8 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 162MN UT WOS:000078350900014 PM 9917336 ER PT J AU Minniti, D Zijlstra, AA Alonso, MV AF Minniti, D Zijlstra, AA Alonso, MV TI The stellar populations of NGC 3109: Another dwarf irregular galaxy with a Population II stellar halo SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : individual (NGC 3109, DDO 236); galaxies : irregular; galaxies : stellar content; galaxy : formation; Local Group ID LOCAL GROUP GALAXIES; RED GIANT BRANCH; NEARBY GALAXIES; STAR-FORMATION; GLOBULAR-CLUSTERS; MAGELLANIC CLOUD; NGC-3109; PHOTOMETRY; DISTANCE; MASS AB We have obtained V- and I-band photometry for about 17,500 stars in the held of the dwarf irregular galaxy NGC 3109, located in the outskirts of the Local Group. The photometry allows us to study the stellar populations present inside and outside the disk of this galaxy. From the VI color-magnitude diagram, we infer metallicities and ages for the stellar populations in the main body and in the halo of NGC 3109. The stars in the disk of this galaxy have a wide variety of ages, including very young stars of age similar to 10(7) yr. Our main result is to establish the presence of a halo consisting of Population II stars, extending out to about 4".5 (or 1.8 kpc) above and below the plane of this galaxy. For these old stars we derive an age of over 10(10) yr and a metallicity of [Fe/H] = -1.8 +/- 0.2. We construct a deep luminosity function, obtaining an accurate distance modulus (m - M)(0) = 25.62 +/- 0.1 for this galaxy based on the I-magnitude of the red giant branch tip and adopting E(V - I) = 0.05. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Pontificia Univ Catolica Chile, Dept Astron, Santiago 22, Chile. Univ Manchester, Inst Sci & Technol, Dept Phys, Manchester M60 1QD, Lancs, England. European So Observ, D-85748 Garching, Germany. Univ Nacl Cordoba, Astron Observ, RA-5000 Cordoba, Argentina. RP Minniti, D (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-413, Livermore, CA 94550 USA. EM dminniti@llnl.gov; Albert.Zijlstra@umist.ac.uk; vicky@oac.uncor.edu NR 64 TC 53 Z9 56 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD FEB PY 1999 VL 117 IS 2 BP 881 EP 893 DI 10.1086/300735 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 172CT UT WOS:000078905300017 ER PT J AU Alcock, C Allsman, RA Alves, DR Axelrod, TS Becker, AC Bennett, DP Bersier, DF Cook, KH Freeman, KC Griest, K Guern, JA Lehner, M Marshall, SL Minniti, D Peterson, BA Pratt, MR Quinn, PJ Rodgers, AW Stubbs, CW Sutherland, W Tomaney, A Vandehei, T Welch, DL AF Alcock, C Allsman, RA Alves, DR Axelrod, TS Becker, AC Bennett, DP Bersier, DF Cook, KH Freeman, KC Griest, K Guern, JA Lehner, M Marshall, SL Minniti, D Peterson, BA Pratt, MR Quinn, PJ Rodgers, AW Stubbs, CW Sutherland, W Tomaney, A Vandehei, T Welch, DL TI The MACHO project LMC variable star inventory. VIII. The recent star formation history of the Large Magellanic Cloud from the Cepheid period distribution SO ASTRONOMICAL JOURNAL LA English DT Article DE Cepheids; Magellanic Clouds; stars : formation ID STELLAR MODELS; MAGNITUDES; OPACITIES; CLUSTERS; COLORS; MASS AB We present an analysis of the period distribution of about 1800 Cepheids in the LMC, based on data obtained by the MACHO microlensing experiment and on a previous catalog by C. H. Payne Gaposchkin. Using stellar evolution and pulsation models, we construct theoretical period-frequency distributions that are compared with the observations. These models reveal that a significant burst of star formation has occurred recently in the LMC (similar to 1.15 x 10(8) yr). We also show that during the last similar to 10(8) yr, the main center of star formation has been propagating from southeast to northwest along the bar. We find that the evolutionary masses of Cepheids are still smaller than pulsation masses by similar to 7% and that the red edge of the Cepheid instability strip could be slightly bluer than indicated by theory. There are approximately 600 Cepheids with periods below similar to 2.5 days that cannot be explained by evolution theory. We suggest that they are anomalous Cepheids and that a number of these stars are double-mode Cepheids. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Australian Natl Univ, Mt Stromlo & Siding Spring Observ, Weston, ACT 2611, Australia. Univ Washington, Dept Astron, Seattle, WA 98195 USA. Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. Pontificia Univ Catolica Chile, Dept Astron & Astrofis, Santiago 22, Chile. European So Observ, D-85748 Garching, Germany. Univ Oxford, Dept Phys, Oxford OX1 3RH, England. McMaster Univ, Dept Phys & Astron, Hamilton, ON L8S 4M1, Canada. RP Alcock, C (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. EM alcock@beowulf.llnl.gov RI Stubbs, Christopher/C-2829-2012; Quinn, Peter/B-3638-2013 OI Stubbs, Christopher/0000-0003-0347-1724; NR 32 TC 44 Z9 44 U1 0 U2 1 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 FEB PY 1999 VL 117 IS 2 BP 920 EP 926 DI 10.1086/300736 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 172CT UT WOS:000078905300020 ER PT J AU Jun, BI Jones, TW AF Jun, BI Jones, TW TI Radio emission from a young supernova remnant interacting with an interstellar cloud: Magnetohydrodynamic simulation with relativistic electrons SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic rays; hydrodynamics; ISM : clouds; MHD radiation; mechanisms : nonthermal ID DIFFUSIVE SHOCK ACCELERATION; PARTICLE-ACCELERATION; CASSIOPEIA-A; X-RAY; MAGNETIC-FIELDS; MAXIMUM ENERGY; COSMIC BULLETS; GAS CLOUDS; EVOLUTION; ORIGIN AB We present two-dimensional MHD simulations of the evolution of a young Type Ia supernova remnant (SNR) during its interaction with an interstellar cloud of comparable size at impact. We include for the first time in such simulations explicit relativistic electron transport. This was done using a simplified treatment of the diffusion-advection equation, thus allowing us to model injection and acceleration of cosmic-ray electrons at shocks and their subsequent transport. From this information we also model radio synchrotron emission, including spectral information. The simulations were carried out in spherical coordinates with azimuthal symmetry and compare three different situations, each incorporating an initially uniform interstellar magnetic field oriented in the polar direction on the grid. In particular, we modeled the SNR-cloud interactions for a spherical cloud on the polar axis, a toroidal cloud whose axis is aligned with the polar axis, and, for comparison, a uniform medium with no cloud. We find that the evolution of the overrun cloud qualitatively resembles that seen in simulations of simpler but analogous situations: that is, the cloud is crushed and begins to be disrupted by Rayleigh-Taylor and Kelvin-Helmholtz instabilities. However, we demonstrate here that, in addition, the internal structure of the SNR is severely distorted as such clouds are engulfed. This has important dynamical and observational implications. The principal new conclusions we draw from these experiments are the following. (1) Independent of the cloud interaction, the SNR reverse shock can be an efficient site for particle acceleration in a young SNR. (2) The internal flows of the SNR become highly turbulent once it encounters a large cloud. (3) An initially uniform magnetic field is preferentially amplified along the magnetic equator of the SNR, primarily because of biased amplification in that region by Rayleigh-Taylor instabilities. A similar bias produces much greater enhancement to the magnetic energy in the SNR during an encounter with a cloud when the interstellar magnetic field is partially transverse to the expansion of the SNR. The enhanced magnetic fields have a significant radial component, independent of the field orientation external to the SNR. This leads to a strong equatorial bias in synchrotron brightness that could easily mask any enhancements to electron-acceleration efficiency near the magnetic equator of the SNR. Thus, to establish the latter effect, it will be essential to establish that the magnetic field in the brightest regions are actually tangential to the blast wave. (4) The filamentary radio structures correlate well with "turbulence-enhanced" magnetic structures, while the diffuse radio emission more closely follows the gas-density distribution within the SNR. (5) At these early times, the synchrotron spectral index due to electrons accelerated at the primary shocks should be close to 0.5 unless those shocks are modified by cosmic-ray proton pressures. While that result is predictable, we find that this simple result can be significantly complicated in practice by SNR interactions with clouds. Those events can produce regions with significantly steeper spectra. Especially if there are multiple cloud encounters, this interaction can lead to nonuniform spatial spectral distributions or, through turbulent mixing, produce a spectrum that is difficult to relate to the actual strength of the blast wave. (6) Interaction with the cloud enhances the nonthermal electron population in the SNR in our simulations because of additional electron injection taking place in the shocks associated with the cloud. Together with point 3, this means that SNR-cloud encounters can significantly increase the radio emission from the SNR. C1 Univ Minnesota, Dept Astron, Minneapolis, MN 55455 USA. Univ Minnesota, Inst Supercomp, Minneapolis, MN 55455 USA. RP Jun, BI (reprint author), Lawrence Livermore Natl Lab, POB 808,L-630, Livermore, CA 94551 USA. EM jun2@llnl.gov; twj@msi.umn.edu NR 65 TC 56 Z9 56 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 1999 VL 511 IS 2 BP 774 EP 791 DI 10.1086/306694 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 176NN UT WOS:000079158100023 ER PT J AU Hix, WR Thielemann, FK AF Hix, WR Thielemann, FK TI Silicon burning. II. Quasi-equilibrium and explosive burning SO ASTROPHYSICAL JOURNAL LA English DT Article DE nuclear reactions, nucleosynthesis, abundances; stars : evolution; supernovae : general ID CORE-COLLAPSE; SUPERNOVAE; NUCLEOSYNTHESIS; PROPAGATION; CONVECTION; EJECTA; FLAMES AB Having examined the application of quasi-equilibrium to hydrostatic silicon burning in Paper I of this series, we now turn our attention to explosive silicon burning. Previous authors have shown that for material that is heated to high temperature by a passing shock and then cooled by adiabatic expansion, the results can be divided into three broad categories, incomplete burning, normal freezeout, and alpha-rich freezeout, with the outcome depending on the temperature, density, and cooling timescale. In all three cases, we find that the important abundances obey quasi-equilibrium for temperatures greater than approximately 3 x 10(9) K, with relatively little nucleosynthesis occurring following the breakdown of quasi-equilibrium. We will show that quasi-equilibrium provides better abundance estimates than global nuclear statistical equilibrium, even for normal freezeout, and particularly for alpha-rich freezeout. We will also examine the accuracy with which the final nuclear abundances can be estimated from quasiequilibrium. C1 Oak Ridge Natl Lab, Joint Inst Heavy Ion Res, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Univ Texas, Dept Astron, Austin, TX 78712 USA. Univ Basel, Dept Phys & Astron, CH-4056 Basel, Switzerland. RP Hix, WR (reprint author), Oak Ridge Natl Lab, Joint Inst Heavy Ion Res, Oak Ridge, TN 37831 USA. RI Hix, William/E-7896-2011 OI Hix, William/0000-0002-9481-9126 NR 24 TC 55 Z9 56 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 FEB 1 PY 1999 VL 511 IS 2 BP 862 EP 875 DI 10.1086/306692 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 176NN UT WOS:000079158100031 ER PT J AU Fryer, CL Colgate, SA Pinto, PA AF Fryer, CL Colgate, SA Pinto, PA TI Iron opacity and the pulsar of SN 1987A SO ASTROPHYSICAL JOURNAL LA English DT Article DE pulsars : general; stars : neutron; supernovae : general; supernovae : individual (SN 1987A) ID NEUTRON-STAR ACCRETION; LARGE MAGELLANIC CLOUD; SUPERNOVA; BURST AB Neutron stars formed in Type II supernovae are likely to be initially obscured by late-time fallback. Although much of the late-time fallback is quickly accreted via neutrino cooling, some material remains on the neutron star, forming an atmosphere that slowly accretes through photon emission. In this paper, we derive structure equations of the fallback atmosphere and present results of one-dimensional simulations of that fallback. The atmosphere remaining after neutrino cooling (L-v) becomes unimportant (L-v less than or similar to L-Edd,L-e-, the Compton Eddington limit) is only a fraction of the total mass accreted (less than or similar to 10(-8) M-acc = 10(-9) M.). Recombined iron dominates the opacity in the outer regions, leading to an opacity 10(3)-10(4) times higher than that of electron scattering alone. The resultant photon emission of the remnant atmosphere is limited to less than or similar to 10(-3) L-Edd,L-e-. The late-time evolution of this system leads to the formation of a photon-driven wind from the accretion of the inner portion of the atmosphere, leaving, for most cases, a bare neutron star on timescales shorter than 1 yr. The degenerate remnant of 1987A may not be a black hole. Instead, the fallback material may have already accreted or blown off in the accretion-driven wind. If the neutron star has either a low magnetic field or a low rotational spin frequency, we would not expect to see the neutron star remnant of 1987A. C1 Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. RP Fryer, CL (reprint author), Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA. NR 27 TC 38 Z9 38 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 FEB 1 PY 1999 VL 511 IS 2 BP 885 EP 895 DI 10.1086/306701 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 176NN UT WOS:000079158100033 ER PT J AU Drinkwater, MJ Phillipps, S Gregg, MD Parker, QA Smith, RM Davies, JI Jones, JB Sadler, EM AF Drinkwater, MJ Phillipps, S Gregg, MD Parker, QA Smith, RM Davies, JI Jones, JB Sadler, EM TI The fornax spectroscopic survey: The number of unresolved compact galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : compact; galaxies : general; galaxies : starburst ID EMISSION-LINE GALAXIES; SURFACE BRIGHTNESS; LIGHT; QSOS AB We describe a sample of 13 bright (18.5 < B-J < 20.1), compact galaxies at low redshift (0.05 < z < 0.21) behind the Fornax Cluster. These galaxies are unresolved on UK Schmidt sky survey plates, and so they would be missing from most galaxy catalogs compiled from this material. The objects were found during initial observations of The Fornax Spectroscopic Survey. This project is using the Two-degree Field spectrograph on the Anglo-Australian Telescope to obtain spectra for a complete sample of all 14,000 objects, stellar and nonstellar, with 16.5 < B-J < 19.7, in a 12 deg(2) area centered on the Fornax Cluster of galaxies. The surface density of compact galaxies with magnitudes 16.5 < B-J < 19.7 is 7 +/- 3 deg(-2), representing 2.8% +/- 1.6% of all local (z < 0.2) galaxies to this limit. There are 12 +/- 3 deg(-2) with 16.5 < B-J < 20.2. They are luminous (-21.5 < M-B < -18.0, for H-o = 50 km s(-1) Mpc(-1)), and most have strong emission lines (H alpha equivalent widths of 40-200 Angstrom) and small sizes typical of luminous H II galaxies and compact narrow emission line galaxies. Four out of 13 have red colors and early-type spectra, and so they are unlikely to have been detected in any previous surveys. C1 Univ New S Wales, Sch Phys, Sydney, NSW 2052, Australia. Univ Bristol, Dept Phys, Bristol BS8 1TL, Avon, England. Univ Calif Davis, Livermore, CA 94550 USA. Univ Calif Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. Anglo Australian Observ, Epping, NSW 2121, Australia. Univ Wales Coll Cardiff, Dept Phys & Astron, Cardiff CF2 3YB, S Glam, Wales. Univ Sydney, Sch Phys, Sydney, NSW 2006, Australia. RP Drinkwater, MJ (reprint author), Univ New S Wales, Sch Phys, Sydney, NSW 2052, Australia. RI Drinkwater, Michael/A-2201-2008; OI Drinkwater, Michael/0000-0003-4867-0022; Sadler, Elaine/0000-0002-1136-2555; Jones, Bryn/0000-0002-4679-5625 NR 36 TC 28 Z9 29 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 FEB 1 PY 1999 VL 511 IS 2 BP L97 EP L100 DI 10.1086/311844 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 176NP UT WOS:000079158200008 ER PT J AU Gordon, SM Duric, N Kirshner, RP Goss, WM Viallefond, F AF Gordon, SM Duric, N Kirshner, RP Goss, WM Viallefond, F TI A new sample of radio-selected and optically confirmed supernova remnants in M33 SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE galaxies : individual (M33); galaxies : ISM; radio continuum : ISM; supernova remnants ID EMISSION-LINE PROPERTIES; LARGE MAGELLANIC CLOUD; X-RAY-EMISSION; COSMIC-RAYS; ASTRONOMICAL DATA; CYGNUS LOOP; SPECTROPHOTOMETRY; GALAXY; CM; MORPHOLOGY AB Using radio data to identify and optical data to confirm, we have established the largest and most complete sample of extragalactic radio-bright supernova remnants (SNRs) in the nearby spiral galaxy M33. We have identified 53 radio SNRs, doubling the size of the earlier survey by Duric et al. The increased sample size provides more insight into the nature of SNRs and provides an extensive informational database about SNRs for future studies. The SNR sample was analyzed for statistical trends that relate to the evolution of their radio emission. We report no significant correlation between the radio flux densities and diameters of SNRs in our sample. The absence of a statistically meaningful Sigma-D relation is consistent with the view that environmental factors govern the radio evolution of SNRs. A new radio luminosity function for SNRs is presented. Although there appears to be a break in the function, the break is the result of selection effects and not intrinsic to the sample. A comparison of the radio luminosity function with the integrated radio continuum properties of M33 suggests that SNRs may well be the primary source of the relativistic electrons in M33. A histogram of synchrotron spectral indices of the SNRs is presented. Statistical analysis of the spectral index distribution indicates that the mean spectral index of SNRs in M33 is steeper than the mean in samples of SNRs in the Galaxy or the LMC and is consistent with a particle spectrum expected from a diffusive shock acceleration process. C1 Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ New Mexico, Dept Phys & Astron, Albuquerque, NM 87131 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. Observ Paris, Meudon Sect, F-92190 Meudon, France. RP Gordon, SM (reprint author), Lawrence Berkeley Lab, Bldg 50,Room 232,1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 68 TC 76 Z9 76 U1 0 U2 0 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 FEB PY 1999 VL 120 IS 2 BP 247 EP 264 DI 10.1086/313175 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 192RZ UT WOS:000080094000004 ER PT J AU van Aardenne, JA Carmichael, GR Levy, H Streets, D Hordijk, L AF van Aardenne, JA Carmichael, GR Levy, H Streets, D Hordijk, L TI Anthropogenic NOx emissions in Asia in the period 1990-2020 SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE NOx emissions; fossil fuels; Asia energy use; transportation; power sector ID DIOXIDE EMISSIONS; FUEL COMBUSTION; POLLUTION; WORLD; CHINA; SO2 AB Nitrogen oxides emissions in Asia during the period 1990-2020 due to anthropogenic activity are presented. These estimates are based on the RAINS-ASIA methodology (Foell et al., 1995, Acid Rain and Emission Reduction in Asia, World Bank), which includes a dynamic model for energy forecasts, and information on 6 energy sectors and 9 fuel types. The energy forecasts are combined with process emission factors to yield NO, emission estimates at the country level, the regional level, and on a 1 degree by 1 degree grid. In 1990 the total NO, emissions are estimated to be similar to 19 Tg NO2, with China (43 %), India (18 %) and Japan (13 %) accounting for 75 % of the total. Emissions by fuel are dominated by burning of hard coal and emissions by economic activity are dominated by the power. transport, and industrial sectors. These new estimates of NO, emissions are compared with those published by Hameed and Dignon (1988, Atmospheric Environment 22, 441-449) and Akimoto and Narita (1994, Atmospheric Environment 28, 213-225). Future emissions under a no- further-control scenario are also presented. During the period 1990-2020 the NOx emissions increase by 350%, to similar to 86 Tg NO2. The increase in NOx emissions by sector and end-use varies between countries, but in all countries this increase is strongest in the power and transport sectors. These results highlight the dynamic nature of energy use in Asia, and the need to take the rapid growth in NO, emissions in Asia into account in studies of air pollution and atmospheric chemistry. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Agr Univ Wageningen, Wageningen Ctr Environm & Climate Studies, NL-6700 HB Wageningen, Netherlands. Univ Iowa, Ctr Global & Reg Environm Res, Iowa City, IA USA. Univ Iowa, Dept Chem & Biochem Engn, Iowa City, IA USA. Geophys Fluid Dynam Lab, Princeton, NJ USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP van Aardenne, JA (reprint author), Agr Univ Wageningen, Wageningen Ctr Environm & Climate Studies, POB 9101, NL-6700 HB Wageningen, Netherlands. OI Streets, David/0000-0002-0223-1350 NR 30 TC 160 Z9 164 U1 3 U2 36 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD FEB PY 1999 VL 33 IS 4 BP 633 EP 646 DI 10.1016/S1352-2310(98)00110-1 PG 14 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 160KN UT WOS:000078229700012 ER PT J AU Lee, PCS Zaveri, RA Easter, RC Peters, LK AF Lee, PCS Zaveri, RA Easter, RC Peters, LK TI On the parallelization of a global climate-chemistry modeling system SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE atmospheric chemistry modeling; domain-decomposition; load-balancing; Message Passing Interface ID TRANSPORT AB Coupled climate-chemistry simulations are computationally intensive owing to the spatial and temporal scope of the problem. In global chemistry models, the time integrations encountered in the chemistry and aerosol modules usually comprise the major CPU consumption. Parallelization of these segments of the code can contribute to multifold CPU speed-ups with minimal modification of the original serial code. This technical note presents a single program-multiple data (SPMD) strategy applied to the time-split chemistry modules of a coupled climate - global tropospheric chemistry model. Latitudinal domain decomposition is adopted along with a dynamic load-balancing technique that uses the previous time-step's load/latitude estimates for distributing the latitude bands amongst the processors. The coupled model is manually parallelized using the Message Passing Interface standard (MPI) on a distributed memory platform (IBM-SP2), Load-balancing efficiencies and the associated MPI overheads are discussed. Overall speed-ups and efficiencies are also calculated for a series of runs employing up to eight processors. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Sci Applicat Int Corp, Ctr Atmospher Phys, Mclean, VA 22102 USA. Pacific NW Lab, Atmospher Sci Grp, Richland, WA 99352 USA. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. RP Lee, PCS (reprint author), Sci Applicat Int Corp, Ctr Atmospher Phys, 1710 Goodridge Dr,MS 2-3-1, Mclean, VA 22102 USA. EM pius.lee@apo.saic.com RI Lee, Pius/D-5201-2016; OI Zaveri, Rahul/0000-0001-9874-8807 NR 19 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 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD FEB PY 1999 VL 33 IS 4 BP 675 EP 681 DI 10.1016/S1352-2310(98)00272-6 PG 7 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 160KN UT WOS:000078229700015 ER PT J AU Elliott, S Blake, DR Rowland, FS AF Elliott, S Blake, DR Rowland, FS TI Rapid industrialization in developing countries: the challenge to earth system research for the new millennium SO ATMOSPHERIC ENVIRONMENT LA English DT Article C1 Univ Calif Los Alamos Natl Lab, Div Earth & Environm Sci, Atmospher Sci Grp, Los Alamos, NM 87545 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA. RP Elliott, S (reprint author), Univ Calif Los Alamos Natl Lab, Div Earth & Environm Sci, Atmospher Sci Grp, Los Alamos, NM 87545 USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD FEB PY 1999 VL 33 IS 4 BP 683 EP 684 DI 10.1016/S1352-2310(98)00189-7 PG 2 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 160KN UT WOS:000078229700016 ER PT J AU Shannon, JD AF Shannon, JD TI Regional trends in wet deposition of sulfate in the United States and SO2 emissions from 1980 through 1995 SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE acid rain; source-receptor; sulfate; wet deposition; trend analysis ID PRECIPITATION CHEMISTRY AB Regional trends of seasonal and annual wet deposition and precipitation-weighted concentrations (PWCs) of sulfate in the United States over the period 1980-1995 were developed from monitoring data and scaled to a mean of unity. To reduce some effects of year to year climatological variability, the unitless regional deposition and PWC trends were averaged thereafter termed CONCDEP. The SO2 emissions data over the same period from the United States, Canada, and northern Mexico, aggregated by state and province, were weighted appropriately for each deposition region in turn to produce scaled trends of the emissions affecting each region. The emission-weighting factors, which were held constant year to year, were estimated by exercise of a regional transport model. The sulfate CONCDEP regional trends are generally similar to those of regionally weighted SO2 emissions, although the latter trends are less steep and the former trends have more year to year variability. In eastern regions, sulfate CONCDEPs and SO2 emissions patterns both generally show an initial decrease, an essentially trendless middle period? and a final decrease as reductions mandated by the Acid Rain Provisions of the 1990 Clean Air Act Amendments began. Linear regressions of regional sulfate CONCDEPs on corresponding regionally weighted SO2 emissions produced statistically significant relationships in all regions. The analysis indicated that although regional sulfate CONCDEPs decreased relatively faster than did SO2 emissions during the period in all regions except the Great Plains, in general the slopes were not significantly different from unity. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. RP Shannon, JD (reprint author), Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. NR 23 TC 40 Z9 42 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD FEB PY 1999 VL 33 IS 5 BP 807 EP 816 DI 10.1016/S1352-2310(98)00143-5 PG 10 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 164MU UT WOS:000078468800012 ER PT J AU Beamer, LJ Carroll, SF Eisenberg, D AF Beamer, LJ Carroll, SF Eisenberg, D TI The three-dimensional structure of human bactericidal permeability-increasing protein - Implications for understanding protein-lipopolysaccharide interactions SO BIOCHEMICAL PHARMACOLOGY LA English DT Article DE LPS-binding proteins; lipopolysaccharide; bactericidal; X-ray crystallography; inflammation ID AMINO-TERMINAL FRAGMENT; BINDING-PROTEIN; (LPS)-BINDING PROTEIN; SOLUBLE CD14; LPS; ACTIVATION; ENDOTOXIN; SEPSIS; PHOSPHOLIPIDS; PURIFICATION AB Gram-negative bacterial infections are often complicated by the inflammatory properties of lipopolysaccharides (LPS) on or released from the bacterial outer membrane. When present in the mammalian bloodstream, LPS can trigger a series of pathological changes, sometimes resulting in septic shock. Two related mammalian proteins, bactericidal/permeability-increasing protein (BPI) and lipopolysaccharide-binding protein (LBP), are known to affect the LPS-induced inflammatory response and are, therefore, of clinical interest. The recently determined three-dimensional structure of human BPI provides information on the overall protein fold, domain organization, and conserved regions of these two proteins. In addition, the discovery of two apolar lipid binding pockets in BPI indicates a possible site of interaction with LPS. The BPI structure is a powerful tool for the design of site-directed mutants, peptide mimetics/inhibitors, and BPI/LBP chimeras. These studies should help further define the functions of BPI and LBP, and their mechanism of interaction with LPS. (C) 1998 Elsevier Science Inc. C1 Univ Missouri, Dept Biochem, Columbia, MO 65211 USA. Xoma Corp, Berkeley, CA 94710 USA. Univ Calif Los Angeles, Inst Mol Biol, Struct Biol Lab, DOE, Los Angeles, CA 90095 USA. RP Beamer, LJ (reprint author), Univ Missouri, Dept Biochem, Columbia, MO 65211 USA. EM beamerl@missouri.edu NR 34 TC 41 Z9 44 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0006-2952 J9 BIOCHEM PHARMACOL JI Biochem. Pharmacol. PD FEB 1 PY 1999 VL 57 IS 3 BP 225 EP 229 DI 10.1016/S0006-2952(98)00279-2 PG 5 WC Pharmacology & Pharmacy SC Pharmacology & Pharmacy GA 152CN UT WOS:000077758200001 PM 9890549 ER PT J AU Cho, MR Knowles, DW Smith, BL Moulds, JJ Agre, P Mohandas, N Golan, DE AF Cho, MR Knowles, DW Smith, BL Moulds, JJ Agre, P Mohandas, N Golan, DE TI Membrane dynamics of the water transport protein aquaporin-1 in intact human red cells SO BIOPHYSICAL JOURNAL LA English DT Article ID FLUORESCENCE PHOTOBLEACHING RECOVERY; HUMAN-ERYTHROCYTE MEMBRANE; LATERAL MOBILITY; GLYCOPHORIN-A; ROTATIONAL MOBILITY; MOLECULAR-STRUCTURE; BAND-3 PROTEIN; CHANNEL; BLOOD; CHIP AB Aquaporin-1 (AQP1) is the prototype integral membrane protein water channel. Although the three-dimensional structure and water transport function of the molecule have been described, the physical interactions between AQP1 and other membrane components have not been characterized. Using fluorescein isothiocyanate-anti-Co3 (FITC-anti-Co3), a reagent specific for an extracellular epitope on AQP1, the fluorescence photobleaching recovery (FPR) and fluorescence imaged microdeformation (FIMD) techniques were performed on intact human red cells. By FPR, the fractional mobility of fluorescently labeled AQP1 (F-alpha AQP1) in the undeformed red cell membrane is 66 +/- 10% and the average lateral diffusion coefficient is (3.1 +/- 0.5) x 10(-11) cm(2)/s. F-alpha AQP1 fractional mobility is not significantly affected by antibody-induced immobilization of the major integral proteins band 3 or glycophorin A, indicating that AQP1 does not exist as a complex with these proteins. FIMD uses pipette aspiration of individual red cells to create a constant but reversible skeletal density gradient, F-alpha AQP1 distribution, like that of lipid-anchored proteins, is not at equilibrium after microdeformation. Over time, similar to 50% of the aspirated F-alpha AQP1 molecules migrate toward the membrane portion that had been maximally dilated, the aspirated cap. Based on the kinetics of migration, the F-alpha AQP1 lateral diffusion coefficient in the membrane projection is estimated to be 6 x 10(-10) cm(2)/s. These results suggest that AQP1 lateral mobility is regulated in the unperturbed membrane by passive steric hindrance imposed by the spectrin-based membrane skeleton and/or by skeleton-linked membrane components, and that release of these constraints by dilatation of the skeleton allows AQP1 to diffuse much more rapidly in the plane of the membrane. C1 Harvard Univ, Sch Med, Dept Biol Chem & Mol Pharmacol, Boston, MA 02115 USA. Harvard Univ, Sch Med, Dept Med, Boston, MA 02115 USA. Brigham & Womens Hosp, Div Hematol, Boston, MA 02115 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Gamma Biol, Houston, TX 77092 USA. Johns Hopkins Univ, Sch Med, Dept Biol Chem, Baltimore, MD 21205 USA. Johns Hopkins Univ, Sch Med, Dept Med, Baltimore, MD 21205 USA. RP Golan, DE (reprint author), Harvard Univ, Sch Med, Dept Biol Chem & Mol Pharmacol, 250 Longwood Ave, Boston, MA 02115 USA. EM degolan@warren.med.harvard.edu FU NHLBI NIH HHS [HL 15157, HL 32854, HL 33991] NR 49 TC 33 Z9 33 U1 0 U2 5 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1999 VL 76 IS 2 BP 1136 EP 1144 DI 10.1016/S0006-3495(99)77278-4 PG 9 WC Biophysics SC Biophysics GA 162VZ UT WOS:000078368800052 PM 9916045 ER PT J AU Macnaughton, S Stephen, JR Chang, YJ Peacock, A Flemming, CA Leung, K White, DC AF Macnaughton, S Stephen, JR Chang, YJ Peacock, A Flemming, CA Leung, K White, DC TI Characterization of metal-resistant soil eubacteria by polymerase chain reaction - denaturing gradient gel electrophoresis with isolation of resistant strains SO CANADIAN JOURNAL OF MICROBIOLOGY LA English DT Article DE metals; PCR-DGGE; microbial community response ID FATTY-ACID PROFILES; 16S RIBOSOMAL-RNA; MOLECULAR MICROBIAL DIVERSITY; BURKHOLDERIA-CEPACIA; COMMUNITY STRUCTURE; BACTERIA; SEDIMENTS; MICROORGANISMS; RADIONUCLIDES; ACCUMULATION AB Contamination of soils with heavy metal ions is a major problem on industrial and defense-related sites worldwide. The bioavailability and mobility of these contaminants is partially determined by the microbial biomass present at these sites. in this study, we have assessed the effect of the addition of a mixture of toxic metal salts on the prokaryotic community of microcosms consisting of sandy-loam soil using direct molecular analysis of the recoverable eubacterial 16S rDNA molecules by polymerase chain reaction - denaturing gradient gel electrophoresis (PCR-DGGE) and limited phospholipid fatty acid analysis (PLFA). Addition of toxic metals (nonradioactive surrogates of Sr, Ca,Cs, Cd) resulted in rapid (ca. 1 week) changes in the DGGE profile of the indigenous eubacterial community when compared with pristine controls. These changes were stable over the course of the experiment (8 weeks). No changes in the eubacterial population of control microcosms were detected. The major changes in community structure in metal-contaminated microcosms consisted of the appearance of four novel bands not detected in controls. Sequence analysis of these bands suggested that two organisms related to the genus Acinetobacter and two related to the genus Burkholderia carried a selective advantage over other indigenous eubacteria under heavy metal induced stress. The Burkholderia spp. were then cultured and further characterized using lipid analysis. C1 Univ Tennessee, Ctr Environm Biotechnol, Knoxville, TN 37932 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37853 USA. RP White, DC (reprint author), Univ Tennessee, Ctr Environm Biotechnol, 10515 Res Dr,Unit 300, Knoxville, TN 37932 USA. NR 47 TC 13 Z9 14 U1 0 U2 4 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0008-4166 J9 CAN J MICROBIOL JI Can. J. Microbiol. PD FEB PY 1999 VL 45 IS 2 BP 116 EP 124 DI 10.1139/cjm-45-2-116 PG 9 WC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Immunology; Microbiology SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Immunology; Microbiology GA 204JK UT WOS:000080760800003 PM 10380644 ER PT J AU Lemke, RL Izaurralde, RC Nyborg, M Solberg, ED AF Lemke, RL Izaurralde, RC Nyborg, M Solberg, ED TI Tillage and N source influence soil-emitted nitrous oxide in the Alberta Parkland region SO CANADIAN JOURNAL OF SOIL SCIENCE LA English DT Article DE nitrous oxide; thawing soil; tillage; nitrogen fertilizer; manure; fallow ID DENITRIFICATION; EMISSIONS; ATMOSPHERE; EVOLUTION; LOSSES AB Zero tillage systems are receiving attention as possible strategies for sequestering atmospheric carbon. This benefit may be offset by increased N(2)O emissions, which have been reported for soils under zero tillage (ZT) compared to those under more intensive tillage (IT). Comparisons of N(2)O emissions from the two systems have been restricted to the growing season, but substantial losses of N(2)O have been reported during spring thaw events in many regions. Inorganic and organic additions of nitrogen and fallowing have a: so been shown to increase levels of soil-emitted N(2)O. The objectives for this study were: (i) to confirm that losses of N(2)O are higher under ZT than under IT in Alberta Parkland agroecosystems; (ii) to compare the relative influence of urea fertilizer (56 or 100 kg N ha(-1)), field pea residue (dry matter at 5 Mg ha(-1)), sheep manure (dry matter at 40 Mg ha(-1)) additions, and fallow on total N(2)O losses; and (iii) to investigate possible interactions between fertility and tillage treatments. Gas samples were collected using vented soil covers at three sites near Edmonton, Alberta during 1993, 1994, and 1995. Gas samples were analyzed using a gas chromatograph equipped with a (63)Ni; electron capture detector. Estimated annual N(2)O loss ranged from 0.1 to 4.0 kg N ha(-1). Emissions during summer were slightly higher, similar, or lower on ZT compared to those under IT, but were consistently lower on ZT plots during spring thaw. Combined estimates (spring plus summer) of N(2)O loss under ZT were equal to or lower than those under IT. Highest overall losses were observed on fallow plots, followed by fertilizer, pea residue, and then either manure or control plots. We conclude that ZT management systems have potential for reducing agricultural greenhouse gas emissions in the Alberta Parkland region. C1 Agr & Agri Food Canada, Semiarid Prairie Agr Res Ctr, Swift Current, SK S9H 3X2, Canada. Battelle Pacific NW Natl Lab, Washington, DC 20024 USA. Univ Alberta, Dept Renewable Resources, Edmonton, AB T6G 2E3, Canada. Alberta Agr Food & Rural Dev, Edmonton, AB T6H 4P2, Canada. RP Lemke, RL (reprint author), Agr & Agri Food Canada, Semiarid Prairie Agr Res Ctr, Swift Current, Swift Current, SK S9H 3X2, Canada. EM lemker@em.agr.ca RI Izaurralde, Roberto/E-5826-2012 NR 17 TC 85 Z9 87 U1 1 U2 17 PU AGRICULTURAL INST CANADA PI OTTAWA PA 280 ALBERT ST, SUITE 900, OTTAWA, ONTARIO K1P 5G8, CANADA SN 0008-4271 J9 CAN J SOIL SCI JI Can. J. Soil Sci. PD FEB PY 1999 VL 79 IS 1 BP 15 EP 24 PG 10 WC Soil Science SC Agriculture GA 186EG UT WOS:000079713900003 ER PT J AU Foord, EE Hughes, JM Cureton, F Maxwell, CH Falster, AU Sommer, AJ Hlava, PF AF Foord, EE Hughes, JM Cureton, F Maxwell, CH Falster, AU Sommer, AJ Hlava, PF TI Esperanzaite, NaCa2Al2(As5+O4)(2)F-4(OH)center dot 2H(2)O, a new mineral species from the La Esperanza mine, Mexico: Descriptive mineralogy and atomic arrangement SO CANADIAN MINERALOGIST LA English DT Article DE esperanzaite; new mineral species; crystal structure; La Esperanza mine; Durango; Mexico AB Esperanzaite, ideally NaCa2Al2(As5+O4)(2)F-4(OH). 2H(2)O, Z = 2, is a new mineral species from the La Esperanza mine, Durango State, Mexico. The mineral occurs as blue-green botryoidal crystalline masses on rhyolite, with separate spheres up to 1.5 mm in diameter. The Mohs hardness is 4 1/2, and the specific gravity, 3.24 (obs.) and 3.36(3) (calc.). Optical properties were measured in 589 nm light. Esperanzaite is biaxial (-), X = Y = Z = colorless, alpha 1.580(1), beta 1.588(1), and gamma 1.593(1); 2V(obs) is 74(1)degrees and 2V(calc) is 76.3 degrees. The dispersion is medium, r < v, and the optic axes are oriented according to a boolean AND Z = +50.5 degrees, b = Y, c boolean AND X = +35 degrees. The strongest five X-ray-diffraction maxima in the powder pattern [d in Angstrom(I)(hkl)] are: 2.966(100)(13 (1) over bar, 31 (1) over bar, 031), 3.527(90)(220), 2.700(90)(221,002,040), 5.364(80)(001,020) and 4.796(80)(011). Esperanzaite is monoclinic, a 9.687(5), b 10.7379(6), c 5.5523(7) Angstrom, beta 105.32(1)degrees, space group P2(1)/m. The atomic arrangement of esperanzaite was solved by direct methods and Fourier analysis (R = 0.032). The Fundamental Building Block (FBB) is formed of [001] stacks of heteropolyhedral tetramers; the tetramers are formed of two arsenate tetrahedra and two Al octahedra, corner-linked in four-member rings. The FBBs are linked by irregular Na phi(5) and Ca phi(8) polyhedra. C1 US Geol Survey, Denver Fed Ctr, Lakewood, CO 80225 USA. Miami Univ, Dept Geol, Oxford, OH 45056 USA. Univ New Orleans, Dept Geol & Geophys, New Orleans, LA 70148 USA. Miami Univ, Dept Chem & Biochem, Oxford, OH 45056 USA. Sandia Natl Labs, Dept 1822, Albuquerque, NM 87185 USA. RP Foord, EE (reprint author), US Geol Survey, Denver Fed Ctr, MS 905,box 25046, Lakewood, CO 80225 USA. NR 3 TC 3 Z9 3 U1 0 U2 0 PU MINERALOGICAL ASSOC CANADA PI NEPEAN PA CITYVIEW 78087, NEPEAN, ONTARIO K2G 5W2, CANADA SN 0008-4476 J9 CAN MINERAL JI Can. Mineral. PD FEB PY 1999 VL 37 BP 67 EP 72 PN 1 PG 6 WC Mineralogy SC Mineralogy GA 201QA UT WOS:000080605400007 ER PT J AU Li, D Peng, MS Murata, T AF Li, D Peng, MS Murata, T TI Coordination and local structure of magnesium in silicate minerals and glasses: MgK-edge XANES study SO CANADIAN MINERALOGIST LA English DT Article DE MgK-edge XANES; silicate minerals; CaMgSi2O3-NaAlSi3O8 glasses; coordination of Mg ID HIGH-TEMPERATURE MG-25; K-EDGE; MOLECULAR-DYNAMICS; SPECTROSCOPY; MGSIO3; PRESSURE; MELTS; SCATTERING; TRANSITION; FORSTERITE AB We present Mg K-edge XANES spectra of selected Mg-bearing oxide and silicate minerals with different coordination states of Mg. The Mg K-edge peak shifts to higher energy with increasing coordination, from Mg-[4] in spinel, to Mg-[5]. in grandidierite, to Mg-[6] in diopside and many other silicates, and to Mg-[8] in pyrope. The correlation between the energy of the Mg K-edge and Mg-O bond distance of the model minerals is also established; it can be used to estimate the average Mg-O bond distance in disordered systems. The curve fitting of Mg K-edge XANES spectra may be used to distinguish the coordination of Mg, and to determine the relative proportion of different coordination sites, as demonstrated in yoderite, which contains both Mg-[5] and Mg-[6]. The structural role of Mg in CaMgSi2O6 (Di) - NaAlSi3O8 (Ab) glasses was studied using Mg K-edge XANES spectra. The Mg-O bond distance in these glasses is estimated to be 2.00 +/- 0.04 Angstrom. Thus, Mg in these glasses may be five-coordinated with oxygen, or Mg may have multiple structural sites, Mg-[4], Mg-[5] and Mg-[6]. Structurally, the Di-Ab glasses may possess a medium-range order, and have dramatically different multiple scattering (MS) paths from those of crystalline model minerals. C1 Zhongshan Univ, Coll Earth & Environm Sci, Guangzhou 510275, Peoples R China. Univ Calif Los Alamos Natl Lab, Div Earth & Environm Sci, Los Alamos, NM 87545 USA. RP Li, D (reprint author), Zhongshan Univ, Coll Earth & Environm Sci, Guangzhou 510275, Peoples R China. RI Li, Dien/N-6370-2014 NR 28 TC 43 Z9 43 U1 4 U2 23 PU MINERALOGICAL ASSOC CANADA PI NEPEAN PA CITYVIEW 78087, NEPEAN, ONTARIO K2G 5W2, CANADA SN 0008-4476 J9 CAN MINERAL JI Can. Mineral. PD FEB PY 1999 VL 37 BP 199 EP 206 PN 1 PG 8 WC Mineralogy SC Mineralogy GA 201QA UT WOS:000080605400019 ER PT J AU Meldrum, A Boatner, LA Zinkle, SJ Wang, SX Wang, LM Ewing, RC AF Meldrum, A Boatner, LA Zinkle, SJ Wang, SX Wang, LM Ewing, RC TI Effects of dose rate and temperature on the crystalline-to-metamict transformation in the ABO(4) orthosilicates SO CANADIAN MINERALOGIST LA English DT Article DE zircon; hafnon; thorite; huttonite; metamict state; amorphization; irradiation ID BEAM-INDUCED AMORPHIZATION; RADIATION-DAMAGE; ZIRCON; MONAZITE; THORITE; MINERALS; CERAMICS; COMPLEX AB Displacive radiation-induced effects that accumulate during geological time in the uranium- and thorium-bearing orthosilicate minerals zircon, hafnon, thorite, and huttonite were investigated by ion-bombardment techniques and compared with radiation-damaged natural specimens. The atomic-scale changes in microstructure that occur with increasing dose of radiation are similar in both cases, but a polycrystalline microstructure occurs in the natural minerals that has only been found in synthetic specimens irradiated at elevated temperature. For ion-beam-irradiated synthetic crystals and natural crystalline thorite from the Kipawa complex, western Quebec, the dose required for amorphization increases with increasing temperature. At temperatures above 600 degrees C, the amorphization dose increases in the order: Kipawa thorite, synthetic thorite, hafnon, zircon and huttonite. The synthetic polymorphs of ThSiO4 require a similar dose for amorphization at temperatures below 500 degrees C; thus huttonite is not intrinsically more radiation-damage-resistant than thorite. Rather, huttonite recrystallizes more rapidly at elevated temperatures. The temperature above which amorphization cannot be induced by alpha-decay processes was calculated by further developing and applying a recently derived model that can also predict the transformation from the crystalline to metamict state in zircon as a function of age and temperature. The model was refined and expanded to include thorite and huttonite. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Michigan, Dept Nucl Engn & Radiol Sci, Ann Arbor, MI 48109 USA. Univ Michigan, Dept Geol Sci, Ann Arbor, MI 48109 USA. RP Meldrum, A (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. OI Zinkle, Steven/0000-0003-2890-6915; Boatner, Lynn/0000-0002-0235-7594 NR 57 TC 48 Z9 48 U1 1 U2 9 PU MINERALOGICAL ASSOC CANADA PI NEPEAN PA CITYVIEW 78087, NEPEAN, ONTARIO K2G 5W2, CANADA SN 0008-4476 J9 CAN MINERAL JI Can. Mineral. PD FEB PY 1999 VL 37 BP 207 EP 221 PN 1 PG 15 WC Mineralogy SC Mineralogy GA 201QA UT WOS:000080605400020 ER PT J AU Chapline, G AF Chapline, G TI A unique theory of gravity and matter SO CHAOS SOLITONS & FRACTALS LA English DT Article ID SUPER-TODA MOLECULE; LAST HOPF MAP; QUANTUM-GRAVITY; FIELD-EQUATIONS; 8 DIMENSIONS; F-THEORY; SUPERMEMBRANE; SUPERSTRINGS AB The author has previously suggested that the ground state for 4-dimensional quantum gravity can be represented as a condensation of non-linear gravitons connected by Dirac strings. In this note we suggest that the low-lying excitations of this state can be described by a quasi-topological action of the form integral d(13)z F-4 boolean AND F-5 boolean AND F-4, corresponding to a trilinear coupling of solilonic 8-branes and 7-branes. It is shown that when the excitations associated with F-5 are neglected, the effective action can be interpreted as a theory of conformal gravity in four dimensions. This in turn suggests that ordinary gravity as well supersymmetric matter and phenomenological gauge symmetries arise from the spontaneous breaking of topological invariance. The possibly deep mathematical significance of this theory is also noted. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Chapline, G (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 29 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 0960-0779 J9 CHAOS SOLITON FRACT JI Chaos Solitons Fractals PD FEB-MAR PY 1999 VL 10 IS 2-3 BP 311 EP 318 DI 10.1016/S0960-0779(98)00166-0 PG 8 WC Mathematics, Interdisciplinary Applications; Physics, Multidisciplinary; Physics, Mathematical SC Mathematics; Physics GA 179BB UT WOS:000079302700012 ER PT J AU Chapline, G Granik, A AF Chapline, G Granik, A TI Moyal quantization, holography and the quantum geometry of surfaces SO CHAOS SOLITONS & FRACTALS LA English DT Article ID COHERENT STATES; INFINITY AB An elementary introduction is provided to the phase space quantization method of Moyal and Wigner. We generalize the method so that it applies to 2-dimensional surfaces, where it has an interesting connection with quantum holography. In the case of Riemann surfaces the connection between Moyal quantization and holography provides new insights into the Torelli theorem and the quantization of nonlinear integrable models. Quantum holography may also serve as a model for a quantum theory of membranes. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Pacific, Dept Phys, Stockton, CA 95211 USA. RP Chapline, G (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. EM chapline1@llnl.gov NR 20 TC 2 Z9 2 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0960-0779 J9 CHAOS SOLITON FRACT JI Chaos Solitons Fractals PD FEB-MAR PY 1999 VL 10 IS 2-3 BP 319 EP 328 DI 10.1016/S0960-0779(98)00201-X PG 10 WC Mathematics, Interdisciplinary Applications; Physics, Multidisciplinary; Physics, Mathematical SC Mathematics; Physics GA 179BB UT WOS:000079302700013 ER PT J AU Krawetz, B AF Krawetz, B TI Ensuring marketable SO CHEMICAL ENGINEERING LA English DT Article C1 Lockheed Martin Idaho Technol Co, LMITCO, Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Krawetz, B (reprint author), Lockheed Martin Idaho Technol Co, LMITCO, Idaho Natl Engn & Environm Lab, POB 1625, Idaho Falls, ID 83415 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU CHEMICAL WEEK ASSOCIATES PI NEW YORK PA 888 SEVENTH AVE, 26TH FL, NEW YORK, NY 10106 USA SN 0009-2460 J9 CHEM ENG-NEW YORK JI Chem. Eng. PD FEB PY 1999 VL 106 IS 2 BP 96 EP + PG 4 WC Engineering, Chemical SC Engineering GA 166YW UT WOS:000078606500019 ER PT J AU Sandi, G Thiyagarajan, P Carrado, KA Winans, RE AF Sandi, G Thiyagarajan, P Carrado, KA Winans, RE TI Small angle neutron scattering characterization of the porous structure of carbons prepared using inorganic templates SO CHEMISTRY OF MATERIALS LA English DT Article ID LITHIUM BATTERIES; INSERTION; ANODE AB Small angle neutron scattering (SANS) was used for the characterization of the microstructure of carbons derived from organic-loaded inorganic template materials that are used as anodes in lithium ion cells. Pillared clays (PILC), layered silicates whose sheets have been permanently propped open by sets of thermally stable molecular props, were used as a template to load the organic precursors. Five organic precursors, namely pyrene, styrene, pyrene/trioxane copolymer, ethylene, and propylene, were used to load the PILC. Pyrolysis was carried out at 700 degrees C under nitrogen atmosphere. From SANS, information has been derived about the pore radius, mass fractal dimension, and the cutoff length (above which the fractal property breaks down) on each carbon. In general, the pore radius ranges from 4 to 11 Angstrom, and the mass fractal dimension varies in the range from 2.5 to 2.9. Contrast-match SANS studies of carbons wetted in 84% deuterated toluene indicate that a significant amount of pores in carbon from pyrene are not accessible to the solvent, while most of the porous network of carbon from propylene is accessible. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Argonne Natl Lab, Div Intense Pulsed Neutron Source, Argonne, IL 60439 USA. RP Sandi, G (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. EM gsandi@anl.gov NR 25 TC 24 Z9 24 U1 2 U2 16 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 FEB PY 1999 VL 11 IS 2 BP 235 EP 240 DI 10.1021/cm980333j PG 6 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 176EY UT WOS:000079139400012 ER PT J AU Anderson, MA Trouw, FR Tam, CN AF Anderson, MA Trouw, FR Tam, CN TI Properties of water in calcium- and hexadecyltrimethylammonium-exchanged bentonite SO CLAYS AND CLAY MINERALS LA English DT Article DE bentonite; diffusion; HDTMA; neutron scattering; water ID 2ND HARMONIC-GENERATION; ELASTIC NEUTRON-SCATTERING; ORGANIC-COMPOUNDS; PARA-NITROPHENOL; ADSORBED WATER; CLAYS; AIR; MONTMORILLONITE; CHLOROPHENOLS; INTERFACE AB Dynamical and thermodynamic properties of water at room temperature in Ca- and hexadecyltrimethylammonium- (HDTMA) exchanged bentonite were determined for 4 different water contents (similar to 0.03-0.55 g water g(-1) clay). Incoherent quasi-elastic neutron scattering (QENS) was used to measure the translational and rotational mobility of water in the clays, while chilled mirror dewpoint psychrometry measured water activity of the samples, differential scanning calorimetry (DSC) provided information about the temperature of dehydration and X-ray diffraction (XRD) quantified layer spacings for the clays. The neutron scattering data were fit to a jump diffusion model that yielded mean jump lengths, jump diffusion residence times and rotational relaxation times for water in the clays. Mean jump lengths were quite similar for the 2 different cation saturations at equivalent water contents, and decreased with increasing water content. The fitted jump lengths ranged from 0.27-0.5 nm and were 2-4 times larger than that found for bulk water (0.13 nm). jump diffusion residence times were 3-30 times longer than that for bulk water (1.2 ps) and also decreased with increasing water content. The residence times were somewhat shorter for HDTMA-clay as compared with Ca-clay at equivalent water contents. Rotational motion was less strongly influenced than translational motion by the presence of the clay surface. The energy state of water in the 2 cation saturations were quite different; dehydration temperatures for the HDTMA-clay were approximately 30 degrees C lower than the Ca-clay at equal water contents, while water activities, as P/P-0, were up to 0.6 units higher. A linear relationship was found between water activity and the translational diffusion coefficient, although at the highest water content, the diffusion coefficient of water for the HDTMA-clay was approximately 30% higher than that measured for bulk water. C1 Univ Calif Riverside, Dept Soil & Environm Sci, Riverside, CA 92521 USA. Argonne Natl Lab, Intense Pulsed Neutron Source, Argonne, IL 60439 USA. RP Univ Calif Riverside, Dept Soil & Environm Sci, Riverside, CA 92521 USA. NR 28 TC 36 Z9 36 U1 0 U2 8 PU CLAY MINERALS SOC PI CHANTILLY PA 3635 CONCORDE PKWY, STE 500, CHANTILLY, VA 20151-1125 USA SN 0009-8604 EI 1552-8367 J9 CLAY CLAY MINER JI Clay Clay Min. PD FEB PY 1999 VL 47 IS 1 BP 28 EP 35 DI 10.1346/CCMN.1999.0470103 PG 8 WC Chemistry, Physical; Geosciences, Multidisciplinary; Mineralogy; Soil Science SC Chemistry; Geology; Mineralogy; Agriculture GA 173KA UT WOS:000078978700003 ER PT J AU Compton, JS Conrad, ME Vennemann, TW AF Compton, JS Conrad, ME Vennemann, TW TI Stable isotope evolution of volcanic ash layers during diagenesis of the Miocene Monterey formation, California SO CLAYS AND CLAY MINERALS LA English DT Article DE bentonite; diagenesis; monterey formation; stable isotopes; volcanic ash ID SANTA-MARIA BASIN; CLAY-MINERALS; HYDROGEN-ISOTOPE; JOAQUIN BASIN; WATER; EXCHANGE; BURIAL; ROCKS; USA; GEOCHEMISTRY AB The oxygen and hydrogen isotope compositions of volcanic ash layers from coastal outcrops of the Miocene Monterey Formation elucidate the progressive burial diagenesis of glass to bentonite and metabentonite. Volcanic glass that texturally appears unaltered is found to have delta(18)O and delta D values that are significantly higher than fresh volcanic glasses. The positive shift in delta(18)O and delta D values is proportional to the amount of hydration and chemical alteration of the glass samples. Initial hydration of the glass results in the exchange of Na for H; later hydration results in the loss of K and Fe in exchange for H and Na. The delta(18)O values of the most hydrated glass, and clay minerals from bentonite and metabentonite layers are approximately in equilibrium with slightly modified seawater. The delta D values of the hydrated glass, and clay minerals from bentonite and metabentonite layers, are significantly depleted in D relative to seawater and suggest meteoric exchange associated with tectonic uplift and erosion in the Pliocene and Pleistocene. Smectite from bentonite layers has delta(18)O and delta D values similar to the most hydrated glass samples, suggesting similar glass-water and smectite-water fractionation factors. Kaolinite and mixed-layered illite-smectite (I-S) altered from smectite have lower delta(18)O and higher delta D values than their precursor. The delta(18)O and delta D of nonvolcanic siliceous mudstones from the Pt. Arguello oil field show an unusual decrease in delta D with increasing burial depth that probably reflects the presence of organic hydrogen in the analyzed samples as well as possible D-depleted formation waters from detrital illite-water and hydrocarbon-water exchange. C1 Univ Cape Town, Dept Geol Sci, ZA-7700 Rondebosch, South Africa. Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Isotope Geochem, Berkeley, CA 94720 USA. Univ Tubingen, Inst Geochem, D-72074 Tubingen, Germany. RP Compton, JS (reprint author), Univ Cape Town, Dept Geol Sci, ZA-7700 Rondebosch, South Africa. RI Conrad, Mark/G-2767-2010; Compton, John/E-1767-2013 NR 50 TC 9 Z9 9 U1 0 U2 2 PU CLAY MINERALS SOC PI CHANTILLY PA 3635 CONCORDE PKWY, STE 500, CHANTILLY, VA 20151-1125 USA SN 0009-8604 EI 1552-8367 J9 CLAY CLAY MINER JI Clay Clay Min. PD FEB PY 1999 VL 47 IS 1 BP 84 EP 95 DI 10.1346/CCMN.1999.0470109 PG 12 WC Chemistry, Physical; Geosciences, Multidisciplinary; Mineralogy; Soil Science SC Chemistry; Geology; Mineralogy; Agriculture GA 173KA UT WOS:000078978700009 ER PT J AU Duffy, PB Caldeira, KG AF Duffy, PB Caldeira, KG TI Sensitivity of simulated salinities in a three dimensional ocean general circulation model to vertical mixing of destabilizing surface fluxes SO CLIMATE DYNAMICS LA English DT Article ID DEEP CONVECTION; GREENLAND-SEA; ICE FORMATION; WORLD OCEAN; PARAMETERIZATIONS; EQUILIBRIUM; LAYER AB We present simulations performed with a three dimensional global ocean general circulation model which show that simulated salinities and amounts of convective mixing are very sensitive to vertical mixing of surface buoyancy fluxes. If, as usual, surface buoyancy fluxes are placed entirely in the topmost model level, our model produces excessive convective mixing in the Southern Ocean. This results in poor stimulated salinity in the Southern Ocean. In this simulation, we assume, as usual, that both surface buoyancy forcing and vertical mixing are homogeneous within each grid cell. If, on the other hand, destabilizing surface fluxes are instantaneously mixed into the subsurface ocean, the model produces much less convective mixing and much more realistic salinities. The vertical mixing of surface buoyancy fluxes performed in this simulation is equivalent to assuming that those fluxes affect only a small fraction of each grid cell, and cause vertical mixing only in that limited area. Our interpretation of these results is that the usual assumption that both surface buoyancy forcing and vertical mixing are uniform within each grid cell has a detrimental effect on model results; these results could be significantly improved by good parametrizations which treat the horizontal inhomogeneity of surface buoyancy forcing and of vertical mixing. C1 Univ Calif Lawrence Livermore Natl Lab, Climate Syst Modeling Grp, Livermore, CA 94550 USA. RP Duffy, PB (reprint author), Univ Calif Lawrence Livermore Natl Lab, Climate Syst Modeling Grp, L-103,POB 808, Livermore, CA 94550 USA. EM pduffy@llnl.gov RI Caldeira, Ken/E-7914-2011 NR 19 TC 5 Z9 5 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0930-7575 J9 CLIM DYNAM JI Clim. Dyn. PD FEB PY 1999 VL 15 IS 2 BP 81 EP 88 DI 10.1007/s003820050269 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 164NY UT WOS:000078471500001 ER PT J AU Cheng, RK Bedat, B AF Cheng, RK Bedat, B TI Effects of buoyancy on lean premixed v-flames - Part I: Laminar and turbulent flame structures SO COMBUSTION AND FLAME LA English DT Article ID JET DIFFUSION FLAMES; MICROGRAVITY; GRAVITY; BEHAVIOR AB Laser schlieren and planar laser-induced fluorescence techniques have been used to investigate laminar and turbulent v-flames in +g, -g, and mu g under flow conditions that span the regimes of momentum domination (Ri < 0.1) and buoyancy domination (Ri > 0.1). Overall flame features shown by schlieren indicate that buoyancy dominates the entire flow field for conditions close to Ri = 1. With decreasing Ri, buoyancy effects are observed only in the far-field regions. Analyses of the mean flame angles demonstrate that laminar and turbulent flames do not have similar responses to buoyancy. Difference in the laminar +g and -g flame angles decrease with Ri (i.e., increasing Re) and converge to the mu g flame angle at the momentum limit (Ri = 0). This is consistent with the notion that the effects of buoyancy diminish with increasing flow momentum. The +g and -g turbulent flame angles, however, do not converge at Ri = 0. As shown by OH-PLIF images, the inconsistency in +g and -g turbulent flame angles is associated with the differences in flame wrinkles. Turbulent flame wrinkles evolve more slowly in +g than in -g. The difference in flame wrinkle structures, however, cannot be explained in terms of buoyancy effects on flame instability mechanisms. It seems to be associated with the field effects of buoyancy that stretches the turbulent flame brushes in tg and compresses the flame brush in -g. Flame wrinkling offers a mechanism through which the flame responds to the field effects of buoyancy despite increasing flow momentum. These observations point to the need to include both upstream and downstream contributions in theoretical analysis of flame turbulence interactions. (C) 1998 by The Combustion Institute. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. Univ Alberta, Dept Mech Engn, Edmonton, AB, Canada. RP Cheng, RK (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. NR 20 TC 21 Z9 27 U1 0 U2 2 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD FEB PY 1999 VL 116 IS 3 BP 360 EP 375 DI 10.1016/S0010-2180(98)00063-7 PG 16 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 126MZ UT WOS:000076298600007 ER PT J AU Hopkins, WA Mendonca, MT Congdon, JD AF Hopkins, WA Mendonca, MT Congdon, JD TI Responsiveness of the hypothalamo-pituitary-interrenal axis in an amphibian (Bufo terrestris) exposed to coal combustion wastes SO COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY C-PHARMACOLOGY TOXICOLOGY & ENDOCRINOLOGY LA English DT Article DE amphibians; toads; pollutants; coal combustion wastes; hormones; stress; corticosterone; adrenocorticotropic hormone ID KRAFT MILL EFFLUENT; PLASMA-CORTISOL; OREOCHROMIS-MOSSAMBICUS; RANA-CATESBEIANA; STRESS-RESPONSE; FISH; CORTICOSTERONE; CADMIUM; GLUCOSE; GROWTH AB To assess the responsiveness of the interrenal axis to stress, we injected toads exposed to coal combustion wastes and toads from an unpolluted reference site with adrenocorticotropic hormone (ACTH), as well as the vehicle alone (saline). Initial circulating levels of corticosterone in toads captured at the polluted area were significantly higher than levels in toads from the reference site. Corticosterone levels in toads from the polluted site remained high even after 2 weeks of laboratory acclimation and injection with saline. The results may suggest disruption of hepatic enzymes responsible for the metabolic clearance of steroid hormones. Injection of toads from the polluted site with ACTH had no effect on plasma corticosterone levels, whereas a similar treatment of toads from the reference site stimulated a marked increase in corticosterone. Our study provides evidence that toads exposed to coal combustion wastes may be less efficient at responding to additional environmental stressors. (C) 1999 Elsevier Science Inc. All rights reserved. C1 Auburn Univ, Dept Zool & Wildlife, Auburn, AL 36849 USA. Savannah River Ecol Lab, Aiken, SC 29802 USA. RP Hopkins, WA (reprint author), Auburn Univ, Dept Zool & Wildlife, Auburn, AL 36849 USA. EM hopkins@srel.edu NR 33 TC 51 Z9 52 U1 2 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0742-8413 J9 COMP BIOCHEM PHYS C JI Comp. Biochem. Physiol. C-Pharmacol. Toxicol. Endocrinol. PD FEB PY 1999 VL 122 IS 2 BP 191 EP 196 DI 10.1016/S0742-8413(98)10104-4 PG 6 WC Biochemistry & Molecular Biology; Endocrinology & Metabolism; Toxicology; Zoology SC Biochemistry & Molecular Biology; Endocrinology & Metabolism; Toxicology; Zoology GA 168WF UT WOS:000078715600004 PM 10190044 ER PT J AU Mucke, EP Saias, I Zhu, B AF Mucke, EP Saias, I Zhu, B TI Fast randomized point location without preprocessing in two- and three-dimensional Delaunay triangulations SO COMPUTATIONAL GEOMETRY-THEORY AND APPLICATIONS LA English DT Article DE computational geometry; geometric computing; randomized algorithms; Delaunay triangulations; point location; three dimensional ID COMPUTING DIRICHLET TESSELLATIONS; VORONOI DIAGRAMS; MANIPULATION; SUBDIVISIONS; PRIMITIVES AB This paper studies the point location problem in Delaunay triangulations without preprocessing and additional storage. The proposed procedure finds the query point by simply "walking through" the triangulation, after selecting a "good starting point" by random sampling. The analysis generalizes and extends a recent result for d = 2 dimensions by proving this procedure takes expected time close to O(n(1/(d+1))) for point location in Delaunay triangulations of n random points in d = 3 dimensions. Empirical results in both two and three dimensions show that this procedure is efficient in practice. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. RP Mucke, EP (reprint author), ANSYS Inc, 275 Technol Dr, Canonsburg, PA 15317 USA. RI Zhu, Binhai/A-2911-2008 NR 24 TC 15 Z9 16 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0925-7721 J9 COMP GEOM-THEOR APPL JI Comput. Geom.-Theory Appl. PD FEB PY 1999 VL 12 IS 1-2 BP 63 EP 83 DI 10.1016/S0925-7721(98)00035-2 PG 21 WC Mathematics, Applied; Mathematics SC Mathematics GA 175KH UT WOS:000079092100006 ER PT J AU McPherson, A Painter, J McCormick, P Ahrens, J Ragsdale, C AF McPherson, A Painter, J McCormick, P Ahrens, J Ragsdale, C TI Visualizations of Earth processes for the American Museum of Natural History SO COMPUTER GRAPHICS-US LA English DT Article ID MANTLE C1 Los Alamos Natl Lab, Adv Comp Lab, Los Alamos, NM 87545 USA. NR 10 TC 1 Z9 1 U1 0 U2 1 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 2 PENN PLAZA, STE 701, NEW YORK, NY 10121-0701 USA SN 0097-8930 J9 COMPUT GRAPHICS-US JI Comput. Graph.-US PD FEB PY 1999 VL 33 IS 1 BP 11 EP + PG 6 WC Computer Science, Software Engineering SC Computer Science GA 247PA UT WOS:000083228100007 ER PT J AU Levine, D Gropp, W Forsman, K Kettunen, L AF Levine, D Gropp, W Forsman, K Kettunen, L TI Parallel computation of three-dimensional nonlinear magnetostatic problems SO CONCURRENCY-PRACTICE AND EXPERIENCE LA English DT Article AB We describe a general-purpose parallel code for computing accurate solutions to large computationally demanding, 3D, nonlinear magnetostatic problems, The code, CORAL, is based on a volume integral equation formulation. Using an IBM SP parallel computer and iterative solution methods, we successfully solved the dense linear systems inherent in such formulations. A key component of our work was the use of the PETSc library, which provides parallel portability and access to the latest linear algebra solution technology. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. Tampere Univ Technol, FIN-33610 Tampere, Finland. RP Levine, D (reprint author), Boeing Informat & Support Serv, POB 3707,MS 7L-20, Seattle, WA 98124 USA. OI Gropp, William/0000-0003-2905-3029 NR 11 TC 1 Z9 1 U1 0 U2 1 PU JOHN WILEY & SONS LTD PI CHICHESTER PA THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND SN 1040-3108 J9 CONCURRENCY-PRACT EX JI Concurrency-Pract. Exp. PD FEB PY 1999 VL 11 IS 2 BP 109 EP 120 DI 10.1002/(SICI)1096-9128(199902)11:2<109::AID-CPE320>3.0.CO;2-8 PG 12 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA 197YW UT WOS:000080395200004 ER PT J AU Adams, J Otte, M AF Adams, J Otte, M TI Did Indo-European languages spread before farming? SO CURRENT ANTHROPOLOGY LA English DT Article ID TRANSITION; RECORDS; POLLEN C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Univ Liege, Serv Prehist, B-4000 Liege, Belgium. RP Adams, J (reprint author), Oak Ridge Natl Lab, Div Environm Sci, MS 6335, Oak Ridge, TN 37831 USA. NR 23 TC 18 Z9 18 U1 1 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0011-3204 J9 CURR ANTHROPOL JI Curr. Anthropol. PD FEB PY 1999 VL 40 IS 1 BP 73 EP 77 DI 10.1086/515804 PG 5 WC Anthropology SC Anthropology GA 164QA UT WOS:000078474000005 ER PT J AU Golovanova, LV Hoffecker, JF Kharitonov, VM Romanova, GP AF Golovanova, LV Hoffecker, JF Kharitonov, VM Romanova, GP TI Mezmaiskaya cave: A Neanderthal occupation in the Northern Caucasus SO CURRENT ANTHROPOLOGY LA English DT Article ID EXCAVATIONS; SITE C1 Argonne Natl Lab, Lakewood, CO 80226 USA. Moscow State Univ, Museum Anthropol, Moscow, Russia. Russian Acad Sci, Archaeol Inst, Moscow, Russia. RP Golovanova, LV (reprint author), Moskovskii Prospekt, St Petersburg, Russia. NR 26 TC 65 Z9 67 U1 1 U2 7 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0011-3204 J9 CURR ANTHROPOL JI Curr. Anthropol. PD FEB PY 1999 VL 40 IS 1 BP 77 EP 86 DI 10.1086/515805 PG 10 WC Anthropology SC Anthropology GA 164QA UT WOS:000078474000006 ER PT J AU Campbell, AA AF Campbell, AA TI Interfacial regulation of crystallization in aqueous environments SO CURRENT OPINION IN COLLOID & INTERFACE SCIENCE LA English DT Review ID SELF-ASSEMBLED MONOLAYERS; CALCIUM-OXALATE MONOHYDRATE; INORGANIC MATERIALS; SHELL PROTEINS; NUCLEATION; GROWTH; BIOMINERALIZATION; MICROEMULSIONS; PHOSPHATE; CRYSTALS AB In nature, organisms control crystal nucleation and growth using organic interfaces as templates. Scientists are striving to understand this biological process and adapt it in order to produce synthetic analogs for use as advanced materials and composites. Recently, there has been much work in the area of understanding and controlling crystallization events at organic interfaces in aqueous environments has taken place. C1 Pacific NW Lab, Richland, WA 99352 USA. RP Campbell, AA (reprint author), Pacific NW Lab, POB 999, Richland, WA 99352 USA. NR 46 TC 22 Z9 25 U1 1 U2 10 PU CURRENT SCIENCE LTD PI LONDON PA 34-42 CLEVELAND STREET, LONDON W1P 6LE, ENGLAND SN 1359-0294 J9 CURR OPIN COLLOID IN JI Curr. Opin. Colloid Interface Sci. PD FEB PY 1999 VL 4 IS 1 BP 40 EP 45 DI 10.1016/S1359-0294(99)00014-X PG 6 WC Chemistry, Physical SC Chemistry GA 207MZ UT WOS:000080941800006 ER PT J AU Kingon, AI Streiffer, SK AF Kingon, AI Streiffer, SK TI Ferroelectric films and devices SO CURRENT OPINION IN SOLID STATE & MATERIALS SCIENCE LA English DT Review ID BA0.7SR0.3TIO3 THIN-FILMS; RANDOM-ACCESS MEMORIES; ELECTRICAL-PROPERTIES; HIGH-DENSITY; RESISTANCE DEGRADATION; POLARIZATION FATIGUE; CAPACITORS; ELECTRODES; SRBI2TA2O9; OXIDES AB Recent developments in ferroelectric films have been made in terms of their application in nonvolatile memories and dynamic random access memories. One highlight is the report of a complete description of the temperature-dependent dielectric behavior of (Ba,Sr)TiO3 films as a function of strain, composition, and thickness. For the first time, a direct link has been made between the thin film and bulk electrical properties. C1 N Carolina State Univ, Mat Res Ctr, Raleigh, NC 27695 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP N Carolina State Univ, Mat Res Ctr, Raleigh, NC 27695 USA. EM Angus_Kingon@ncsu.edu; streiffer@anl.gov RI Streiffer, Stephen/A-1756-2009 NR 43 TC 38 Z9 38 U1 2 U2 12 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-0286 EI 1879-0348 J9 CURR OPIN SOLID ST M JI Curr. Opin. Solid State Mat. Sci. PD FEB PY 1999 VL 4 IS 1 BP 39 EP 44 DI 10.1016/S1359-0286(99)80009-6 PG 6 WC Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 222TL UT WOS:000081800800007 ER PT J AU Huang, ZP Jett, JH Keller, RA AF Huang, ZP Jett, JH Keller, RA TI Bacteria genome fingerprinting by flow cytometry SO CYTOMETRY LA English DT Article DE bacteria genome; fingerprinting; flow cytometry; DNA sizing ID DNA CONDENSATION; POLYAMINES; FRAGMENTS AB Background: A now cytometry-based, ultrasensitive fluorescence detection technique has been developed that demonstrates unique advantages in the analysis of large DNA fragments over the currently most widely used technology, pulsed-field gel electrophoresis (PFGE). The technique described herein is used to characterize the restriction fingerprints of the bacteria genome Staphylococcus aureus in this study. Methods:The isolation of the bacterial genomic DNA and the subsequent complete digestion by a restriction endonuclease were performed inside an agarose plug. Electroelution was used to move the DNA fragments out of the agarose plug into a solution containing low concentrations of spermine and spermidine, added to stabilize the large DNA fragments. DNA was stained with the bisintercalating dye thiazole orange homodimer (TOTO-1) and subsequently introduced into our ultrasensitive flow cytometer from a capillary. Results: Individual DNA fragments up to 351 kbp were successfully handled and sized. The histograms of the burst sizes were generated from signals associated with individual fragments in <7 min with <2 pg of DNA. The sizing accuracy was better than 98%. In contrast, standard PFGE takes similar to 20 h and requires similar to 1 mu g of DNA with a sizing accuracy of similar to 90%. Conclusions: With the demonstrated success and advantages, our approach has the potential of being applied to fast, accurate bacteria species and strain identification. (C) 1999 Wiley-Liss, Inc. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM USA. RP Keller, RA (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, MS M888, Los Alamos, NM 87545 USA. FU NCRR NIH HHS [RR-01315] NR 21 TC 19 Z9 21 U1 0 U2 5 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0196-4763 J9 CYTOMETRY JI Cytometry PD FEB 1 PY 1999 VL 35 IS 2 BP 169 EP 175 DI 10.1002/(SICI)1097-0320(19990201)35:2<169::AID-CYTO9>3.0.CO;2-K PG 7 WC Biochemical Research Methods; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 160LB UT WOS:000078231200009 PM 10554173 ER PT J AU Bishop, JKB AF Bishop, JKB TI Transmissometer measurement of POC SO DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS LA English DT Article ID WARM-CORE RING; SUSPENDED PARTICULATE MATTER; EQUATORIAL PACIFIC; BEAM ATTENUATION; ATLANTIC OCEAN; SARGASSO SEA; VARIABILITY; LAYERS; FLUX AB The relationships between beam attenuation coefficient, c, at 660 nm, measured using a Sea Tech transmissometer, and particulate matter concentrations, size distributions, and chemistry determined by the Multiple Unit Large Volume in situ Filtration System (MULVFS) were investigated in the central equatorial Pacific during 1992 US-JGOFS cruises TT007 and TT011. Results from 24 pairs of simultaneous casts to 1000 m from the two 3000 km long transects showed highest correlation between beam attenuation coefficient and particulate organic carbon (POC) when POC was summed over all size classes sampled. Regression of c vs in situ POC data from TT007 and TT011 yields slopes of 6.34 +/- 0.03 and 6.09 +/- 0.03 x 10(-5) m(-1) (nmol Cl-1)(-1), intercepts of 0.366 +/- 0.002 and 0.368 +/- 0.003 m(-1) and r(2) values of 0.97 m and 0.95. A reanalysis of 1982 data from the NW Atlantic and 1996 results from sub-polar NE Pacific waters indicate that the calibration specifics of c vs POC are largely independent of ocean environment, season, or depth sampled. Our results suggest that the transmissometer can provide a quantitatively useful estimate of POC over a diverse suite of oceanographic environments. This opens the opportunity for deploying transmissometers from platforms other than ships to characterize the high-frequency (diurnal and longer time scales) variability of particulate organic carbon within the upper kilometer of the ocean. A framework for interpreting the vast body of beam attenuation coefficient measurements made in the oceans over the past two decades is provided. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Victoria, Sch Earth & Ocean Sci, Victoria, BC, Canada. RP Bishop, JKB (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, 1 Cyclotron Rd M-S 90-1116, Berkeley, CA 94720 USA. NR 32 TC 83 Z9 91 U1 0 U2 11 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0967-0637 J9 DEEP-SEA RES PT I JI Deep-Sea Res. Part I-Oceanogr. Res. Pap. PD FEB PY 1999 VL 46 IS 2 BP 353 EP 369 DI 10.1016/S0967-0637(98)00069-7 PG 17 WC Oceanography SC Oceanography GA 169CL UT WOS:000078729900006 ER PT J AU Barg, A Ashikhmin, A AF Barg, A Ashikhmin, A TI Binomial moments of the distance distribution and the probability of undetected error SO DESIGNS CODES AND CRYPTOGRAPHY LA English DT Article DE distance distribution; binomial moments; rank generating function; undetected error ID CODES AB In [1] K. A. S. Abdel-Ghaffar derives a lower bound on the probability of undetected error for unrestricted codes. The proof relies implicitly on the binomial moments of the distance distribution of the code. We use the fact that these moments count the size of subcodes of the code to give a very simple proof of the bound in [1] by showing that it is essentially equivalent to the Singleton bound. This proof reveals connections of the probability of undetected error to the rank generating function of the code and to related polynomials (Whitney function, Tutte polynomial, and higher weight enumerators). We also discuss some improvements of this bound. Finally, we analyze asymptotics. We show that an upper bound on the undetected error exponent that corresponds to the bound of [1] improves known bounds on this function. C1 Lucent Technol, Bell Labs, Murray Hill, NJ 07974 USA. Univ Calif Los Alamos Natl Lab, Grp CIC 3, Los Alamos, NM 87545 USA. RP Barg, A (reprint author), Lucent Technol, Bell Labs, 600 Mt Ave 2C-375, Murray Hill, NJ 07974 USA. NR 19 TC 10 Z9 10 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0925-1022 J9 DESIGN CODE CRYPTOGR JI Designs Codes Cryptogr. PD FEB PY 1999 VL 16 IS 2 BP 103 EP 116 DI 10.1023/A:1008382528138 PG 14 WC Computer Science, Theory & Methods; Mathematics, Applied SC Computer Science; Mathematics GA 200GT UT WOS:000080531800001 ER PT J AU Pechoux, C Gudjonsson, T Ronnov-Jessen, L Bissell, MJ Petersen, OW AF Pechoux, C Gudjonsson, T Ronnov-Jessen, L Bissell, MJ Petersen, OW TI Human mammary luminal epithelial cells contain progenitors to myoepithelial cells SO DEVELOPMENTAL BIOLOGY LA English DT Article ID HUMAN-BREAST; IMMUNOMAGNETIC SEPARATION; MALIGNANT BREAST; SALIVARY-GLAND; STEM-CELLS; EXPRESSION; DIFFERENTIATION; MORPHOGENESIS; BENIGN; GROWTH AB The origin of the epithelial and myoepithelial cells in the human breast has not been delineated. In this study we have addressed whether luminal epithelial cells and myoepithelial cells are vertically connected, i.e., whether one is the precursor for the other. We used a primary culture assay allowing preservation of basic phenotypic traits of luminal epithelial and myoepithelial cells in culture. The two cell types were then separated immunomagnetically using antibodies directed against lineage-specific cell surface antigens into at best 100% purity. The cellular identity was ascertained by cytochemistry, immunoblotting, and 2-D gel electrophoresis. Luminal epithelial cells were identified by strong expression of cytokeratins 18 and 19 while myoepithelial cells were recognized by expression of vimentin and alpha-smooth muscle actin. We used a previously devised culture medium (CDM4) that allows vigorous expansion of proliferative myoepithelial cells and also devised a medium (CDM6) that allowed sufficient expansion of differentiated luminal epithelial cells based on addition of hepatocyte growth factor/scatter factor. The two different culture media supported each lineage for at least five passages without signs of interconversion. We used parallel cultures where we switched culture media, thus testing the ability of each lineage to convert to the other. Whereas the myoepithelial lineage showed no signs of interconversion, a subset of luminal epithelial cells, gradually, but distinctly, converted to myoepithelial cells. We propose that in the mature human breast, it is the luminal epithelial cell compartment that gives rise to myoepithelial cells rather than the other way around. (C) 1999 Academic Press. C1 Univ Copenhagen, Panum Inst, Dept Anat, Struct Cell Biol Unit,Sect A, DK-2200 Copenhagen N, Denmark. Univ Copenhagen, August Krogh Inst, Zoophysiol Lab, DK-2100 Copenhagen, Denmark. Ernest Orlando Lawrence Berkeley Natl Lab, Div Life Sci, Cell Biol Lab, Berkeley, CA 94720 USA. RP Petersen, OW (reprint author), Univ Copenhagen, Panum Inst, Dept Anat, Struct Cell Biol Unit,Sect A, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark. EM O.W.Petersen@mai.ku.dk RI Ronnov-Jessen OR Ronnovjessen, Lone/A-5981-2013 FU NCI NIH HHS [CA64786-02] NR 40 TC 150 Z9 155 U1 0 U2 1 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0012-1606 J9 DEV BIOL JI Dev. Biol. PD FEB 1 PY 1999 VL 206 IS 1 BP 88 EP 99 DI 10.1006/dbio.1998.9133 PG 12 WC Developmental Biology SC Developmental Biology GA 167BX UT WOS:000078613700007 PM 9918697 ER PT J AU Bennett, DH Kastenberg, WE McKone, TE AF Bennett, DH Kastenberg, WE McKone, TE TI General formulation of characteristic: Time for persistent chemicals in a multimedia environment SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID ORGANIC-COMPOUNDS; SPATIAL RANGE; LIMITING LAW; BEHAVIOR; MODEL; DECAY AB A simple yet representative method for determining the characteristic time a persistent organic pollutant remains in a multimedia environment is presented. The characteristic time is an important attribute for assessing long-term health and ecological impacts of a chemical. Calculating the characteristic time requires information on decay rates in multiple environmental media as well as the proportion of mass in each environmental medium. We explore the premise that using a steady-state distribution of the mass in the environment provides a means to calculate a representative estimate of the characteristic time while maintaining a simple formulation. Calculating the steady-state mass distribution incorporates the effect of advective transport and nonequilibrium effects resulting from the source terms. Using several chemicals, we calculate and compare the characteristic time in a representative multimedia environment for dynamic, steady-state, and equilibrium multimedia models, and also for a single medium model. We demonstrate that formulating the characteristic time based on the steady-state mass distribution in the environment closely approximates the dynamic characteristic time for a range of chemicals and thus can be used in decisions regarding chemical use in the environment. C1 Univ Calif Berkeley, Dept Mech Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Nucl Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Sch Publ Hlth, Berkeley, CA 94720 USA. RP Kastenberg, WE (reprint author), Univ Calif Berkeley, Dept Mech Engn, Berkeley, CA 94720 USA. NR 17 TC 37 Z9 38 U1 1 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD FEB 1 PY 1999 VL 33 IS 3 BP 503 EP 509 DI 10.1021/es980556a PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 164VW UT WOS:000078485100039 ER PT J AU Cremonesi, M Ferrari, M Chinol, M Stabin, MG Grana, C Prisco, G Robertson, C Tosi, G Paganelli, G AF Cremonesi, M Ferrari, M Chinol, M Stabin, MG Grana, C Prisco, G Robertson, C Tosi, G Paganelli, G TI Three-step radioimmunotherapy with yttrium-90 biotin: dosimetry and pharmacokinetics in cancer patients SO EUROPEAN JOURNAL OF NUCLEAR MEDICINE LA English DT Article DE dosimetry; yttrium-90; pretargeting; radioimmunotherapy; biotin ID BIFUNCTIONAL CHELATING AGENT; MONOCLONAL-ANTIBODIES; NUCLEAR-MEDICINE; BREAST-CANCER; THERAPY; Y-90 AB A three-step avidin-biotin approach has been applied as a pretargeting system in radioimmunotherapy (RIT) as an alternative to conventional RIT with directly labelled monoclonal antibodies (MoAbs). Although dosimetric and toxicity studies following conventional RIT have been reported? these aspects have not previously been evaluated in a three-step RIT protocol. This report presents the results of pharmacokinetic and dosimetric studies performed in 24 patients with different tumours. Special consideration was given to the dose delivered to the red marrow and to the haematological toxicity. The possible additive dose to red marrow due to the release of unbound yttrium-90 was investigated. The protocol consisted in the injection of biotinylated MoAbs (first step) followed 1 day later by the combined administration of avidin and streptavidin (second step). After 24 h, biotin radiolabelled with 1.85-2.97 GBq/m(2) of Y-90 was injected (third step). Two different chelating agents, DTPA and DOTA, coupled to biotin, were used in these studies. Indium-111 biotin was used as a tracer of Y-90 to follow the biodistribution during therapy. Serial blood samples and complete urine collection were obtained over 3 days. Whole-body and single-photon emission tomography images were acquired at 1, 16, 24 and 40 h after injection. The sequence of images was used to extrapolate Y-90-biotin time-activity curves. Numerical fitting and compartmental modelling were used to calculate the residence time values (tau) for critical organs and tumour, and results were compared; the absorbed doses were estimated using the MIRDOSE3.1 software. The residence times obtained by the numerical and compartmental models showed no relevant differences (<10%); the compartmental model seemed to be more appropriate, giving a more accurate representation of the exchange between organs. The mean value for the tau in blood was 2.0+/-1.1 h; the mean urinary excretion in the first 24 h was 82.5%+/-10.8%. Without considering any contribution of free Y-90, kidneys, liver, bladder and red marrow mean absorbed doses were 1.62+/-1.14, 0.27+/-0.23, 3.61+/-0.70 and 0.11+/-0.05 mGy/MBq, respectively; the effective dose was 0.32+/-0.06 mSv/MBq, while the dose to the tumour ranged from 0.62 to 15.05 mGy/MBq. The amount of free Y-90 released after the injection proved to be negligible in the case of Y-90-DPTA-DOTA-biotin, but noteworthy in the case of Y-90-DTPA-biotin (mean value: 5.6%+/-2.5% of injected dose), giving an additive dose to red marrow of 0.18+/-0.08 mGy per MBq of injected Y-90-DTPA-biotin. Small fractions of free Y-90 originating from incomplete radiolabelling can contribute significantly to the red marrow dose (3.26 mGy per MBq of free Y-90) and may explain some of the high levels of haematological toxicity observed. These results indicate that pretargeted three-step RIT allows the administraton of high Y-90 activities capable of delivering a high dose to the tumour and sparing red marrow and other normal organs. Although Y-90-biotin clears rapidly from circulation, the use of DOTA-biotin conjugate for a stable chelation of Y-90 is strongly recommended, considering that small amounts of free Y-90 contribute significantly in increasing the red marrow dose. C1 European Inst Oncol, Div Nucl Med, I-20141 Milan, Italy. European Inst Oncol, Div Med Phys, Milan, Italy. European Inst Oncol, Div Epidemiol & Biostat, Milan, Italy. Oak Ridge Inst Sci & Educ, Oak Ridge, TN USA. RP Paganelli, G (reprint author), European Inst Oncol, Div Nucl Med, Via Ripamonti 435, I-20141 Milan, Italy. NR 48 TC 78 Z9 79 U1 0 U2 10 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0340-6997 J9 EUR J NUCL MED JI Eur. J. Nucl. Med. PD FEB PY 1999 VL 26 IS 2 BP 110 EP 120 DI 10.1007/s002590050366 PG 11 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 169EQ UT WOS:000078734900006 PM 9933344 ER PT J AU Rudolph, D Baktash, C Brinkman, MJ Devlin, M Jin, HQ LaFosse, DR Riedinger, LL Sarantites, DG Yu, CH AF Rudolph, D Baktash, C Brinkman, MJ Devlin, M Jin, HQ LaFosse, DR Riedinger, LL Sarantites, DG Yu, CH TI High-spin shell-model states near Ni-56 SO EUROPEAN PHYSICAL JOURNAL A LA English DT Article ID NUCLEI; DIAGONALIZATION; COINCIDENCE; FE-54(10+); MOMENT; CR-48; CR-50 AB High-spin states of nuclei near doubly magic Ni-56 were studied with the reaction Si-28(Ar-36, xpynz alpha) at 136 MeV beam energy. The GAMMASPHERE array in conjunction with the 4 pi charged-particle detector array MICROBALL and neutron detectors were used to detect gamma rays in coincidence with evaporated light particles. The resulting extensive decay schemes of Fe-54, Co-54,Co-55, Ni-56,Ni-57, and Cu-58 are compared to shell model calculations in the fp shell. C1 Lund Univ, Dept Phys, S-22100 Lund, Sweden. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Washington Univ, Dept Chem, St Louis, MO 63130 USA. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. RP Rudolph, D (reprint author), Lund Univ, Dept Phys, S-22100 Lund, Sweden. RI Rudolph, Dirk/D-4259-2009; Devlin, Matthew/B-5089-2013 OI Rudolph, Dirk/0000-0003-1199-3055; Devlin, Matthew/0000-0002-6948-2154 NR 62 TC 64 Z9 64 U1 0 U2 1 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1434-6001 J9 EUR PHYS J A JI Eur. Phys. J. A PD FEB PY 1999 VL 4 IS 2 BP 115 EP 145 DI 10.1007/s100500050212 PG 31 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 171HJ UT WOS:000078857200004 ER PT J AU Kamppeter, T Mertens, FG Sanchez, A Bishop, AR Dominguez-Adame, F Gronbech-Jensen, N AF Kamppeter, T Mertens, FG Sanchez, A Bishop, AR Dominguez-Adame, F Gronbech-Jensen, N TI Finite temperature dynamics of vortices in the two dimensional anisotropic Heisenberg model SO EUROPEAN PHYSICAL JOURNAL B LA English DT Article ID EASY-PLANE FERROMAGNETS; ANTIFERROMAGNET BANI2(PO4)2; MAGNETIC EXCITATIONS; NEUTRON-SCATTERING; MOTION; GRAPHITE; DOMAINS AB We study the effects of finite temperature on the dynamics of non-planar vortices in the classical, two-dimensional anisotropic Heisenberg model with XY- or easy-plane symmetry. To this end, we analyze a generalized Landau-Lifshitz equation including additive white noise and Gilbert damping. Using a collective variable theory with no adjustable parameters we derive an equation of motion for the vortices with stochastic forces which are shown to represent white noise with an effective diffusion constant linearly dependent on temperature. We solve these stochastic equations of motion by means of a Green's function formalism and obtain the mean vortex trajectory and its variance. We find a non-standard time dependence for the variance of the components perpendicular to the driving force. We compare the analytical results with Langevin dynamics simulations and find a good agreement up to temperatures of the order of 25% of the Kosterlitz-Thouless transition temperature. Finally, we discuss the reasons why our approach is not appropriate for higher temperatures as well as the discreteness effects observed in the numerical simulations. C1 Univ Bayreuth, Inst Phys, D-95440 Bayreuth, Germany. Univ Carlos III Madrid, Dept Matemat, Grp Interdisciplinar Sistemas Complicados, Madrid, Spain. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. Univ Complutense Madrid, Fac Fis, Dept Fis Mat, Grp Interdisciplinar Sistemas Complicados, Madrid 28040, Spain. RP Kamppeter, T (reprint author), Univ Bayreuth, Inst Phys, D-95440 Bayreuth, Germany. RI Sanchez, Angel/A-9229-2008; Dominguez-Adame, Francisco/E-4277-2010 OI Sanchez, Angel/0000-0003-1874-2881; Dominguez-Adame, Francisco/0000-0002-5256-4196 NR 34 TC 13 Z9 13 U1 0 U2 2 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 FEB PY 1999 VL 7 IS 4 BP 607 EP 618 DI 10.1007/s100510050653 PG 12 WC Physics, Condensed Matter SC Physics GA 173VZ UT WOS:000079001600016 ER PT J AU Aschieri, P Castellani, L Scarfone, AM AF Aschieri, P Castellani, L Scarfone, AM TI Quantum orthogonal planes: ISOq,r(N) and SOq,r(N) bicovariant calculi and differential geometry on quantum Minkowski space SO EUROPEAN PHYSICAL JOURNAL C LA English DT Article ID POINCARE GROUP; HARMONIC-OSCILLATOR; LIE-ALGEBRAS; R-MATRIX; DEFORMATION; CLASSIFICATION; EQUATION; SOQ(N); GL(N) AB We construct differential calculi on multiparametric quantum orthogonal planes in any dimension N. These calculi are bicovariant under the action of the full inhomogeneous (multiparametric) quantum group ISOq,r(N), and do contain dilatations. If we require bicovariance only under the quantum orthogonal group SOq,r(N), the calculus on the q-plane can be expressed in terms of its coordinates x(a), differentials dx(a) and partial derivatives partial derivative(a) without the need of dilatations, thus generalizing known results: to the multiparametric case. Using real forms that lead to the signature (n + 1, m) with m = n - 1, n, n + 1, we find ISOq,r(n + 1, m) and SOq,r(n + 1, m) bicovariant calculi on the multiparametric quantum spaces. The particular case of the quantum Minkowski space ISOq,r(3, 1)/SOq,r(3, 1) is treated in detail. The conjugated partial derivatives partial derivative(a)* can be expressed as linear combinations of the partial derivative(a). This allows a deformation of the phase-space where no additional operators (besides x(a) and p(a)) are needed. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Div Phys, Berkeley, CA 94720 USA. Univ Turin, Dipartimento Sci & Tecnol Avanzate, I-10125 Turin, Italy. Univ Turin, Dipartimento Fis Teor, I-10125 Turin, Italy. Univ Turin, Ist Nazl Fis Nucl, I-10125 Turin, Italy. Politecn Torino, Dipartimento Fis, I-10129 Turin, Italy. RP Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Div Phys, 1 Cyclotron Rd, Berkeley, CA 94720 USA. EM aschieri@lbl.gov; castellani@to.infn.it; scarfone@polito.it RI Scarfone, Antonio Maria/B-3119-2011; Aschieri, Paolo/J-2965-2012 OI Scarfone, Antonio Maria/0000-0001-6699-5889; NR 73 TC 30 Z9 30 U1 0 U2 1 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1434-6044 EI 1434-6052 J9 EUR PHYS J C JI Eur. Phys. J. C PD FEB PY 1999 VL 7 IS 1 BP 159 EP 175 PG 17 WC Physics, Particles & Fields SC Physics GA 173TX UT WOS:000078996800017 ER PT J AU Dunietz, I AF Dunietz, I TI CP asymmetries in (semi-)inclusive B-0 decays SO EUROPEAN PHYSICAL JOURNAL C LA English DT Article ID B-DECAYS; WEAK DECAYS; VIOLATION; PARTICLES; SYSTEMS; PHYSICS; PHASES AB It was recently pointed out that inclusive B-0(t) decays could show mixing-induced CP violation. The totally inclusive asymmetry is expected to be tiny [O(10(-3))] because of large cancellations among the asymmetries in the charmless, single charm and double charm final states. Enriching particular final state configurations could significantly increase the CP-asymmetry and observability. Such studies can extract fundamental CKM (Cabibbo-Kobayashi-Maskawa) parameters, and (perhaps) even Delta m(B-s). A superb vertex detector could see CP violation with 10(5) (10(6)) flavor-tagged B-s (B-d) mesons within the CKM model. Because the effects could be significantly larger due to new physics, they should be searched for in existing or soon available data samples. C1 Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. RP Fermilab Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 65 TC 9 Z9 9 U1 0 U2 0 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1434-6044 EI 1434-6052 J9 EUR PHYS J C JI Eur. Phys. J. C PD FEB PY 1999 VL 7 IS 2 BP 197 EP 203 PG 7 WC Physics, Particles & Fields SC Physics GA 176JR UT WOS:000079148400002 ER PT J AU Klasen, M AF Klasen, M TI Three jet cross sections in photoproduction at HERA SO EUROPEAN PHYSICAL JOURNAL C LA English DT Article ID PROTON-ANTIPROTON COLLIDER; MASS MULTIJET EVENTS; HARD SCATTERING; COLLISIONS; DISTRIBUTIONS; PHOTON; 3-JET; ORDER AB We calculate three jet cross sections in photoproduction using exact matrix elements for the direct and resolved contributions. Numerical distributions are presented in a generic, irreducible set of variables that allows to disentangle the dynamics of partonic QCD subprocesses from each other and from pure phase space distributions. The results are compared to preliminary data from the ZEUS collaboration at HERA. It is found that the largest contribution comes from photon-gluon fusion in the mass range 36 GeV < M3-jet < 80 GeV. The measured leading jet scattering angle distribution is consistent with the t-channel exchange of a massless fermion in 2 --> 2 scattering, where the third parton is assumed to arise from soft bremsstrahlung. The data are inconsistent with pure phase space and Rutherford scattering distributions. C1 Argonne Natl Lab, Div High Energy Phys, Argonne, IL 60439 USA. RP Klasen, M (reprint author), Argonne Natl Lab, Div High Energy Phys, Argonne, IL 60439 USA. EM klasen@hep.anl.gov NR 25 TC 11 Z9 11 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1434-6044 J9 EUR PHYS J C JI Eur. Phys. J. C PD FEB PY 1999 VL 7 IS 2 BP 225 EP 232 PG 8 WC Physics, Particles & Fields SC Physics GA 176JR UT WOS:000079148400005 ER PT J AU Kladko, K AF Kladko, K TI On the lowest-energy excitations of one-dimensional strongly correlated electrons SO EUROPHYSICS LETTERS LA English DT Article ID SPIN; CHAIN AB It is proven that the lowest excitations E-low(k) of one-dimensional half-integer spin generalized Heisenberg models and half-filled extended Hubbard models are pi-periodic functions. For Hubbard models at fractional fillings E-low(k + 2k(f)) = E-low(k), where 2k(f) = pi n, and n is the number of electrons per unit cell. Moreover, if one of the ground states of the system is magnetic in the thermodynamic limit, then E-low(k) = 0 for any k, so the spectrum is gapless at any wave vector. The last statement is true for any integer or half-integer value of the spin. C1 Max Planck Inst Phys Komplexer Syst, D-01187 Dresden, Germany. Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Max Planck Inst Phys Komplexer Syst, Noethnitzer Str 38, D-01187 Dresden, Germany. EM kladko@lanl.gov NR 20 TC 0 Z9 0 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 0295-5075 J9 EUROPHYS LETT JI Europhys. Lett. PD FEB 1 PY 1999 VL 45 IS 3 BP 354 EP 360 DI 10.1209/epl/i1999-00171-0 PG 7 WC Physics, Multidisciplinary SC Physics GA 163PX UT WOS:000078415300013 ER PT J AU Jordan, GB AF Jordan, GB TI Multiple methods for evaluation of economic and technology development programs: lessons from around the world SO EVALUATION AND PROGRAM PLANNING LA English DT Editorial Material C1 Sandia Natl Labs, Livermore, CA 94550 USA. RP Jordan, GB (reprint author), Sandia Natl Labs, Livermore, CA 94550 USA. NR 0 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 0149-7189 J9 EVAL PROGRAM PLANN JI Eval. Program Plan. PD FEB PY 1999 VL 22 IS 1 BP 53 EP 54 PG 2 WC Social Sciences, Interdisciplinary SC Social Sciences - Other Topics GA 191ZU UT WOS:000080053500006 ER PT J AU McLaughlin, JA Jordan, GB AF McLaughlin, JA Jordan, GB TI Logic models: a tool for telling your program's performance story SO EVALUATION AND PROGRAM PLANNING LA English DT Article DE program theory; program modeling; performance measurement; monitoring and evaluation; Government Performance and Results Act AB Program managers across private and public sectors are being asked to describe and evaluate their programs in new ways. People want managers to present a logical argument for how and why the program is addressing a specific customer need and how measurement and evaluation will assess and improve program effectiveness. Managers do not have clear and logically consistent methods to help them with this task. This paper describes a Logic Model process, a tool used by program evaluators, in enough detail that managers can use it to develop and tell the performance story for their program. The Logic Model describes the logical linkages among program resources, activities, outputs, customers reached, and short, intermediate and longer term outcomes. Once this model of expected performance is produced, critical measurement areas can be identified. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Sandia Natl Labs, Washington, DC 20024 USA. RP Jordan, GB (reprint author), Sandia Natl Labs, 950 Enfant Plaza SW Suite 110, Washington, DC 20024 USA. NR 17 TC 156 Z9 168 U1 3 U2 25 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0149-7189 J9 EVAL PROGRAM PLANN JI Eval. Program Plan. PD FEB PY 1999 VL 22 IS 1 BP 65 EP 72 DI 10.1016/S0149-7189(98)00042-1 PG 8 WC Social Sciences, Interdisciplinary SC Social Sciences - Other Topics GA 191ZU UT WOS:000080053500008 ER PT J AU Hagen, TM Ingersoll, RT Lykkesfeldt, J Liu, JK Wehr, CM Vinarsky, V Bartholomew, JC Ames, BN AF Hagen, TM Ingersoll, RT Lykkesfeldt, J Liu, JK Wehr, CM Vinarsky, V Bartholomew, JC Ames, BN TI (R)-alpha-lipoic acid-supplemented old rats have improved mitochondrial function, decreased oxidative damage, and increased metabolic rate SO FASEB JOURNAL LA English DT Article DE aging; ambulatory activity; MDA; antioxidants; liver ID ACETYL-L-CARNITINE; ALPHA-LIPOIC ACID; CHROMATOGRAPHY MASS-SPECTROMETRY; THIOCTIC ACID; LIQUID-CHROMATOGRAPHY; DEHYDROASCORBIC ACID; LIPID-PEROXIDATION; HEART MITOCHONDRIA; DIHYDROLIPOIC ACID; ASCORBIC-ACID AB A diet supplemented with (R)-lipoic acid, a mitochondrial coenzyme, was fed to old rats to determine its efficacy in reversing the decline in metabolism seen with age. Young (3 to 5 months) and old (24 to 26 months) rats were fed an AlN-93M diet with or without (R)-lipoic acid (0.5% w/w) for 2 wk, killed and their liver parenchymal cells were isolated. Hepatocytes from untreated old rats vs. young controls had significantly lower oxygen consumption (P<0.03) and mitochondrial membrane potential. (R)-Lipoic acid supplementation reversed the age-related decline in O-2 consumption and increased (P<0.03) mitochondrial membrane potential. Ambulatory activity, a measure of general metabolic activity, was almost threefold lower in untreated old rats vs. controls, but this decline was reversed (P<0.005) in old rats fed (R)-lipoic acid. The increase of oxidants with age, as measured by the fluorescence produced on oxidizing 2',7'-dichlorofluorescin, was significantly lowered in (R)-lipoic acid supplemented old rats (P<0.01). Malondialdehyde (MDA) levels, an indicator of lipid peroxidation, were increased fivefold with age in cells from unsupplemented rats. Feeding rats, the (R)-lipoic acid diet reduced MDA levels markedly (P<0.01). Both glutathione and ascorbic acid levels declined in hepatocytes with age, but their loss was completely reversed with (R)-lipoic acid supplementation. Thus, (R)-lipoic acid supplementation improves indices of metabolic activity as well. as lowers oxidative stress and damage evident in aging. C1 Univ Calif Berkeley, Dept Mol & Cell Biol, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Ames, BN (reprint author), Univ Calif Berkeley, Dept Mol & Cell Biol, 401 Barker Hall, Berkeley, CA 94720 USA. EM bnames@uclink4.berkeley.edu RI Lykkesfeldt, Jens/A-1072-2011; Liu, Jiankang/A-1610-2011 OI Lykkesfeldt, Jens/0000-0002-6514-8407; FU NCI NIH HHS [CA39910]; NIEHS NIH HHS [ESO1896] NR 43 TC 201 Z9 212 U1 0 U2 7 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 FEB PY 1999 VL 13 IS 2 BP 411 EP 418 PG 8 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 167CN UT WOS:000078615200021 PM 9973329 ER PT J AU Paisner, JA Lowdermilk, WH Boyes, JD Sorem, MS Soures, JM AF Paisner, JA Lowdermilk, WH Boyes, JD Sorem, MS Soures, JM TI Status of the National Ignition Facility Project SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT IAEA Technical Committee Meeting on Drivers and Ignition Facilities for Inertial Fusion CY FEB 10-MAR 14, 1997 CL OSAKA UNIV, OSAKA, JAPAN SP IAEA HO OSAKA UNIV DE worldwide research; inertial confinement fusion; electric power ID PERFORMANCE AB The ultimate goal of worldwide research in inertial confinement fusion (ICF) is to develop fusion as an inexhaustible, economic, environmentally safe source of electric power. Following nearly 30 years of laboratory and underground fusion experiments, the next step toward this goal is to demonstrate ignition and propagating burn of fusion fuel in the laboratory. The National Ignition Facility (NIF) Project is being constructed at the Lawrence Livermore National Laboratory (LLNL) for just this purpose. NIF will use advanced Nd-glass laser technology to deliver 1.8 MJ of 0.35-mu m laser light in a shaped pulse, several nanoseconds in duration, achieving a peak power of 500 TW. A national community of US laboratories is participating in this project, now in its final design phase. France and the UK are collaborating on development of required technology under bilateral agreements with the US. This paper presents the status of the laser design and development of its principal components and optical elements. (C) 1999 Published by Elsevier Science S.A. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94500 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. Univ Rochester, Laser Energet Lab, Rochester, NY USA. RP Paisner, JA (reprint author), Univ Calif Lawrence Livermore Natl Lab, 7000 East Ave,L-490, Livermore, CA 94500 USA. NR 6 TC 6 Z9 6 U1 2 U2 15 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0920-3796 J9 FUSION ENG DES JI Fusion Eng. Des. PD FEB PY 1999 VL 44 BP 23 EP 33 DI 10.1016/S0920-3796(98)00313-5 PG 11 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 170EM UT WOS:000078793400010 ER PT J AU Bangerter, RO AF Bangerter, RO TI Status of the US heavy ion fusion program SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT IAEA Technical Committee Meeting on Drivers and Ignition Facilities for Inertial Fusion CY FEB 10-MAR 14, 1997 CL OSAKA UNIV, OSAKA, JAPAN SP IAEA HO OSAKA UNIV DE United States; heavy ion fusion; numerical simulation; accelerators ID POWER-PLANT AB In many respects, high-energy accelerators are well suited to inertial fusion power production. Accelerators have long life, good reliability, and high pulse repetition rates. They can also have high efficiency. Nevertheless, existing accelerators have not been designed to be fusion drivers and they have not established that they can produce sufficiently intense beams to drive ICF targets. Establishing that properly designed accelerators can produce the required beams, while retaining the other desirable features of existing accelerators, is the principal scientific goal of the heavy ion fusion program. Until recently, we planned to establish the physics of intense ion beams by building a scaled driver known as ILSE. Because of declining support for fusion research in the US it is not now possible to construct ILSE. Other proposed fusion projects have also been cancelled. Because ILSE will not be built, we have restructured the US heavy ion fusion program. The restructured program is based on a large number of small experiments coupled with an expanded effort in numerical simulation. Experiments on ion sources, injection, matching, beam combining, recirculation, and focusing are underway. The goal of the simulation program is to perform accurate end-to-end simulations of the entire accelerator. The experiments and simulations will establish much of the science of high intensity beams. Reducing cost and increasing accelerator efficiency are also important goals of this scientific research. In addition we are developing key technologies that will reduce cost and increase efficiency. Before the program is in a position to build a full-scale fusion driver, it will be necessary to perform accelerator experiments that are larger than the experiments that are currently in progress. We plan to build a new accelerator to do these experiments. This new accelerator will also be designed to perform experiments on those aspects of target physics that are unique to ions. (C) 1999 Published by Elsevier Science S.A. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Bangerter, RO (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 9 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0920-3796 J9 FUSION ENG DES JI Fusion Eng. Des. PD FEB PY 1999 VL 44 BP 71 EP 79 DI 10.1016/S0920-3796(98)00267-1 PG 9 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 170EM UT WOS:000078793400017 ER PT J AU Nakai, S Logan, BG AF Nakai, S Logan, BG TI Strategy toward inertial fusion energy SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT IAEA Technical Committee Meeting on Drivers and Ignition Facilities for Inertial Fusion CY FEB 10-MAR 14, 1997 CL OSAKA UNIV, OSAKA, JAPAN SP IAEA HO OSAKA UNIV DE implosion; inertial fusion; laser facilities; fusion power plant AB The understanding of implosion physics and the progress of relevant technologies for inertial fusion has led us to a new phase of inertial fusion research: the initiation of the construction of ignition-capable laser facilities (the US National Ignition Facility and the French Megajoule Project). This also led us to consider a new phase for Inertial Fusion Energy (IFE) research, to proceed to IFE,test facilities operating at high pulse rates, once ignition and gain is demonstrated in the ignition class facilities. Many design concepts of IFE power plants have been investigated to clarify the critical issues for achieving technical and economical feasibility. R&D on the critical issues of drivers, targets and chambers for both direct and indirect-drive options have many common engineering issues together with concept-dependent issues. International exchanges and collaborations on these issues are beneficial for efficient development toward the ultimate goal of commercial use of fusion energy. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Osaka Univ, Inst Laser Engn, Suita, Osaka 565, Japan. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Nakai, S (reprint author), Osaka Univ, Inst Laser Engn, 2-6 Yamada Oka, Suita, Osaka 565, Japan. NR 17 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0920-3796 J9 FUSION ENG DES JI Fusion Eng. Des. PD FEB PY 1999 VL 44 BP 97 EP 104 DI 10.1016/S0920-3796(98)00335-4 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 170EM UT WOS:000078793400020 ER PT J AU Boreham, BW Bolton, PR Newman, DS Hora, H Aydin, M Azechi, H Cicchitelli, L Eliezer, S Goldsworthy, MP Hauser, T Kasotakis, G Kitagawa, Y Martinez-Val, JM Mima, K Murakami, M Nishihara, K Piera, M Ray, PS Scheid, W Sarris, E Stening, RJ Takabe, H Velarde, G Yamanaka, M Yamanaka, T Castillo, R Osman, F AF Boreham, BW Bolton, PR Newman, DS Hora, H Aydin, M Azechi, H Cicchitelli, L Eliezer, S Goldsworthy, MP Hauser, T Kasotakis, G Kitagawa, Y Martinez-Val, JM Mima, K Murakami, M Nishihara, K Piera, M Ray, PS Scheid, W Sarris, E Stening, RJ Takabe, H Velarde, G Yamanaka, M Yamanaka, T Castillo, R Osman, F TI Beam matter interaction physics for fast ignitors SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT IAEA Technical Committee Meeting on Drivers and Ignition Facilities for Inertial Fusion CY FEB 10-MAR 14, 1997 CL OSAKA UNIV, OSAKA, JAPAN SP IAEA HO OSAKA UNIV DE fast ignitor scheme; fusion energy; laser interaction; DT-fuel ID FREE-FREE TRANSITIONS; VOLUME IGNITION; NEUTRON YIELD; LASER-PULSES; ACCELERATION; PLASMAS; FUSION; ELECTRONS; LIGHT; SUPERPOSITION AB The fast ignitor scheme for achieving inertial fusion energy precompresses the DT fuel to more than 1000 times the solid state density with nanosecond laser pulses. It then employs a picosecond 10-100-PW laser pulse to deposit with very high efficiency the energy necessary to achieve the ignition temperature of approx. 4 keV. In this way the necessary driver energy for inertial fusion energy reactors is reduced from the megajoule level to the 100-kJ level. In this article, we present results relevant to the development of the fast ignitor scheme that have been achieved in recent years by Australian teams in collaboration with international teams. The topics that are specifically addressed are: (1) forces and relativistic mechanisms of laser interaction with the electrons in the intense picosecond beams; (2) electron and ion emission from the focused beam into the precompressed plasma, including double layer effects and collective stopping power; and (3) the energy of the picosecond beam, which when nearly uniformly deposited into the precompressed DT-fuel can achieve the conditions for high-gain volume ignition. Positive results are derived for volume ignition scheme from considerations of recent high neutron gain laser fusion experiments. (C) 1999 Published by Elsevier Science S.A. All rights reserved. C1 Univ Cent Queensland, Rockhampton, Qld 4702, Australia. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ New S Wales, Sydney, NSW 2052, Australia. Hacettepe Univ, Dept Phys, TR-06532 Ankara, Turkey. Osaka Univ, Inst Laser Engn, Suita, Osaka 565, Japan. Canon Australia, N Ryde, NSW 2113, Australia. Silex Pty Ltd, N Ryde, NSW 2113, Australia. Albat & Wirsam, D-35440 Linden, Germany. Natl Observ, Athens, Greece. Polytech Univ, Madrid, Spain. Def Sci & Technol Org, Salisbury, SA 5108, Australia. Univ Western Sydney Macarthur, Campbelltown, NSW 2560, Australia. RP Boreham, BW (reprint author), Univ Cent Queensland, Rockhampton, Qld 4702, Australia. RI Martinez-Val, Jose/D-3871-2013; Azechi, Hiroshi/H-5876-2015; Mima, Kunioki/H-9014-2016; Nishihara, Katsunobu/J-8172-2016; murakami, masakatsu/I-2309-2015 OI Martinez-Val, Jose/0000-0002-6325-6981; Nishihara, Katsunobu/0000-0002-5572-1169; murakami, masakatsu/0000-0003-2220-7638 NR 60 TC 1 Z9 1 U1 0 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0920-3796 J9 FUSION ENG DES JI Fusion Eng. Des. PD FEB PY 1999 VL 44 BP 215 EP 224 DI 10.1016/S0920-3796(98)00277-4 PG 10 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 170EM UT WOS:000078793400041 ER PT J AU Norreys, PA Bakarezos, M Barringer, L Borghesi, M Beg, FN Castro-Colins, M Chambers, D Dangor, AE Danson, CN Djaoui, A Fews, AP Galliard, R Gibbon, P Gizzi, L Glinsky, ME Hammel, BA Key, MH Lee, P Loukakos, P MacKinnon, AJ Meyer, C Meyer-ter-Vehn, J Moustaizis, S Preston, SG Pukhov, A Rose, SJ Tatarakis, M Wark, JS Willi, O Zepf, M Zhang, J AF Norreys, PA Bakarezos, M Barringer, L Borghesi, M Beg, FN Castro-Colins, M Chambers, D Dangor, AE Danson, CN Djaoui, A Fews, AP Galliard, R Gibbon, P Gizzi, L Glinsky, ME Hammel, BA Key, MH Lee, P Loukakos, P MacKinnon, AJ Meyer, C Meyer-ter-Vehn, J Moustaizis, S Preston, SG Pukhov, A Rose, SJ Tatarakis, M Wark, JS Willi, O Zepf, M Zhang, J TI Studies of the fast ignition route to inertial confinement fusion at the Rutherford Appleton Laboratory SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT IAEA Technical Committee Meeting on Drivers and Ignition Facilities for Inertial Fusion CY FEB 10-MAR 14, 1997 CL OSAKA UNIV, OSAKA, JAPAN SP IAEA HO OSAKA UNIV DE Rutherford Appleton Laboratory; fast ignition; inertial confinement fusion; laser-plasma processes; particle-in-cell calculations ID RAYLEIGH-TAYLOR INSTABILITY; PICOSECOND LASER-PULSE; RESONANT ABSORPTION; TARGETS DRIVEN; SOLID TARGETS; IMPRINT; PLASMA; SIMULATION; LIGHT AB The Rutherford Appleton Laboratory has been at the forefront of investigations into the physics associated with the fast ignition concept for inertial confinement fusion. This scheme involves complex laser-plasma processes, the theoretical understanding of which relies heavily on particle-in-cell calculations. In this paper, three experiments displaying quantitative agreement with detailed multi-dimensional PIC calculations are reviewed: hole-boring velocity measurements; relativistic self-focusing; and harmonic generation from plasma surfaces. Qualitative agreement of hot electron temperature measurements with PIC simulations are also discussed. The authors believe these results are very encouraging for the fast ignition concept. (C) 1999 Published by Elsevier Science S.A. All rights reserved. C1 Rutherford Appleton Lab, Cent Laser Facil, Didcot OX11 0QX, Oxon, England. Univ Crete, IESL, FORTH, GR-71110 Iraklion, Crete, Greece. Univ London Imperial Coll Sci Technol & Med, London SW7 2BZ, England. Univ Oxford, Clarendon Lab, Oxford OX1 3PU, England. Univ Bristol, HH Wills Phys Lab, Bristol BT8 1SL, Avon, England. Univ Jena, Max Planck Gesell, Res Unit Xray Opt, D-07743 Jena, Germany. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. Max Planck Inst Qantenopt, D-85748 Garching, Germany. RP Norreys, PA (reprint author), Rutherford Appleton Lab, Cent Laser Facil, Didcot OX11 0QX, Oxon, England. RI Gizzi, Leonida/F-4782-2011; Borghesi, Marco/K-2974-2012; Lee, Paul/A-8749-2008; Loukakos, Panagiotis/A-8642-2014; Zepf, Matt/M-1232-2014; Gibbon, Paul/C-8811-2015; MacKinnon, Andrew/P-7239-2014; pukhov, alexander/C-8082-2016; OI Lee, Paul/0000-0002-6385-4420; Gibbon, Paul/0000-0002-5540-9626; MacKinnon, Andrew/0000-0002-4380-2906; Gizzi, Leonida A./0000-0001-6572-6492; Rose, Steven/0000-0001-6808-6355 NR 25 TC 2 Z9 2 U1 1 U2 6 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0920-3796 J9 FUSION ENG DES JI Fusion Eng. Des. PD FEB PY 1999 VL 44 BP 239 EP 243 DI 10.1016/S0920-3796(98)00343-3 PG 5 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 170EM UT WOS:000078793400044 ER PT J AU Matzen, MK AF Matzen, MK TI Z pinches as intense X-ray sources for inertial confinement fusion applications SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT IAEA Technical Committee Meeting on Drivers and Ignition Facilities for Inertial Fusion CY FEB 10-MAR 14, 1997 CL OSAKA UNIV, OSAKA, JAPAN SP IAEA HO OSAKA UNIV DE X-ray sources; hohlraum; inertial confinement fusion ID IMPLOSIONS; EMISSION; DENSITY; NUMBER; POWER AB Fast z-pinch implosions can convert more than 10% of the stored electrical energy in a pulsed-power accelerator into X-rays. On the Saturn pulsed-power accelerator at Sandia National Laboratories, currents of 6-8 MA with a risetime of less than 50 ns have been used to drive cylindrically-symmetric arrays of wires, producing X-ray energies greater than 400 kJ with X-ray pulsewidths less than 5 ns and peak X-ray powers of 75 +/- 10 TW. Using similar loads, PBFA Z has produced > 1.5 MJ and > 150 TW of X-rays in the first 4 months of operation in the z-pinch mode. These X-ray energies and powers are records for laboratory X-ray production. The X-ray output can be thermalized into a near-Planckian X-ray source by containing it within a cylindrical radiation case (a hohlraum). These energetic, intense, large volume, long-lived hohlraum X-ray sources have recently been used for ICF-relevant ablator physics experiments and offer the potential for performing many new basic physics and fusion-relevant experiments. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Matzen, MK (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 17 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0920-3796 J9 FUSION ENG DES JI Fusion Eng. Des. PD FEB PY 1999 VL 44 BP 287 EP 293 DI 10.1016/S0920-3796(98)00322-6 PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 170EM UT WOS:000078793400054 ER PT J AU Logan, BG Perry, MD Caporaso, GJ AF Logan, BG Perry, MD Caporaso, GJ TI Concept for high-charge-state ion induction accelerators SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT IAEA Technical Committee Meeting on Drivers and Ignition Facilities for Inertial Fusion CY FEB 10-MAR 14, 1997 CL OSAKA UNIV, OSAKA, JAPAN SP IAEA HO OSAKA UNIV DE ion induction linac accelerators; high-charge-state ions ID MULTIPHOTON IONIZATION AB This work describes a particular concept for ion induction linac accelerators using high-charge-state ions produced by an intense, short pulse laser, and compares the costs of a modular drive system producing 6.5 MJ for a variety of ion masses and charge states using a simple but consistent cost model. (C) 1999 Published by Elsevier Science S.A. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Logan, BG (reprint author), Univ Calif Lawrence Livermore Natl Lab, L-481, Livermore, CA 94550 USA. NR 7 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0920-3796 J9 FUSION ENG DES JI Fusion Eng. Des. PD FEB PY 1999 VL 44 BP 295 EP 301 DI 10.1016/S0920-3796(98)00311-1 PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 170EM UT WOS:000078793400055 ER PT J AU Game, JC Kaufman, PD AF Game, JC Kaufman, PD TI Role of Saccharomyces cerevisiae chromatin assembly factor-I in repair of ultraviolet radiation damage in vivo SO GENETICS LA English DT Article ID UBIQUITIN-CONJUGATING ENZYME; CELL NUCLEAR ANTIGEN; DOUBLE-STRAND BREAKS; DNA-REPAIR; RAD6 PROTEIN; YEAST RAD6; POSTREPLICATION REPAIR; EXCISION-REPAIR; UV MUTAGENESIS; END RULE AB In vitro, the protein complex Chromatin Assembly Factor-I (CAF-l) from human or yeast cells deposits histones onto DNA templates after replication. In Saccharomyces cerevisiae, the CAC1, CAC2, and CAC3 genes encode the three CAF-I subunits. Deletion of any of the three CAC genes reduces telomeric gene silencing and confers an increase in sensitivity; to killing by ultraviolet (mr) radiation. We used double and triple mutants involving cac1 Delta and yeast repair gene mutations to show that deletion of the CACl gene increases the UV sensitivity of cells mutant in genes from each of the known DNA repair epistasis groups. For example, double mutants involving cac1 Delta and excision repair gene deletions rad1 Delta or rad14 Delta showed increased UV sensitivity, as did double mutants involving cac1 Delta and deletions of members of the RAD51 recombinational repair group. cac1 Delta also increased the UV sensitivity of strains with defects in either the error-prone (rev3 Delta) or error-free (pol30-46) branches of RAD6-mediated postrepricative DNA repair but did not substantially increase the sensitivity of strains carrying null mutations in the RAD6 or RAD18 genes. Deletion of CAC1 also increased the UV sensitivity and rate of UV-induced mutagenesis in rad5 Delta mutants, as has been observed for mutants defective in error-free postreplicative repair. Together, these data suggest that CAF-I has a role in error-free posheplicative damage repair and may also have an auxiliary role in other repair mechanisms. Like the CAC genes, RAD6 is also required for gene silencing at telomeres. We find an increased loss of telomeric gene silencing in rad6 Delta cac1 Delta and rad18 Delta cac1 Delta double mutants, suggesting that CAF-I and multiple factors in the postreplicative repair pathway influence chromosome structure. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Donner Lab 351, Div Life Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mol & Cell Biol, Berkeley, CA 94720 USA. RP Kaufman, PD (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Donner Lab 351, Div Life Sci, Berkeley, CA 94720 USA. FU NIGMS NIH HHS [1RO1 GM-55712] NR 64 TC 58 Z9 58 U1 0 U2 5 PU GENETICS PI BALTIMORE PA 428 EAST PRESTON ST, BALTIMORE, MD 21202 USA SN 0016-6731 J9 GENETICS JI Genetics PD FEB PY 1999 VL 151 IS 2 BP 485 EP 497 PG 13 WC Genetics & Heredity SC Genetics & Heredity GA 164KF UT WOS:000078462500007 PM 9927445 ER PT J AU Cole, DR Ripley, EM AF Cole, DR Ripley, EM TI Oxygen isotope fractionation between chlorite and water from 170 to 350 degrees C: A preliminary assessment based on partial exchange and fluid rock experiments SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID HYDROGEN-ISOTOPE; SYSTEMS; DIFFUSION; MINERALS AB Oxygen isotope fractionations in laboratory systems have been determined between chlorite and water at 170-350 degrees C. In one series of experiments, the Northrop-Clayton partial exchange method was used where three (sometimes four) isotopically different waters were reacted with chlorite [(Sigma Fe)/Sigma Fe+Mg = 0.483] for four durations (132-3282 h) at 350 degrees C and 250 b. The percents of exchange determined for the four times from shortest to longest are 4.4, 6.5, 8.0, and 11.9. The fractionations calculated from the Northrop and Clayton (1966) method are in modest agreement for the four run durations: 0.13, 0.26, -0.46, and -0.55 per mil. Errors associated with each of these fractionations are quite large (e.g., +/-1.2 per mil for the longest run). The value determined for the longest run of similar to 20 weeks is the most reliable of the group acid compares very closely with a value of similar to -0.7 per mil estimated by Wenner and Taylor (1971) based on natural chlorites. Good agreement is also observed with the estimates, -1.2 and -1.3 parts per thousand for calculated at 350 degrees C for chlorite compositions with [(Sigma Fe)/Sigma Fe+Mg] = 0.313 and 0.444, respectively, from equations given by Savin and Lee (1988) based on their empirical bond-type method. Additional fractionation data have been estimated from hydrothermal granite-fluid experiments where chlorite formed from biotite. Detailed thin section, scanning electron microscope (SEM), x-ray diffraction (XRD), and electron microprobe analyses demonstrate that biotite is altered exclusively to chlorite in 13 granite-fluid experiments conducted at the following conditions: T = 170-300 degrees C, P = vapor saturation - 200 b, salinity = H2O, 0.1 and 1 m NaCl, fluid/biotite mass ratios = 3-44, run durations = 122-772 h. The amount of chlorite, quantified through point counting and XRD, increased with increasing temperature, salinity, and time. The isotope compositions of chlorite were calculated from mass balance and compared to the final measured delta(18)O of the fluids. The 10(3)In alpha values averaged 0.14, 0.8 and 2.9 per mil for 300 degrees, 250 degrees, and 200 degrees C, respectively. A least-squares regression model of the combined data set (all T's) gives the following expression for fractionation: 1000 ln alpha(chl-w) = 2.693 (10(9)/T-3) - 6.342 (10(6)/T-2) + 2.969 (10(3)/T) The curve described by this equation is in very good agreement with empirical curves given by Wenner and Taylor (1971), Savin and Lee (1988), and Zheng (1993). Copyright (C) 1999 Elsevier Science Ltd. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Indiana Univ, Dept Geol Sci, Bloomington, IN 47405 USA. RP Cole, DR (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. EM coledr@orni.gov NR 36 TC 52 Z9 54 U1 0 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 FEB PY 1999 VL 63 IS 3-4 BP 449 EP 457 DI 10.1016/S0016-7037(99)00071-X PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 207ZD UT WOS:000080964900012 ER PT J AU Ridley, MK Wesolowski, DJ Palmer, DA Kettler, RM AF Ridley, MK Wesolowski, DJ Palmer, DA Kettler, RM TI Association quotients of aluminum sulphate complexes in NaCl media from 50 to 125 degrees C: Results of a potentiometric and solubility study SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID 2ND DISSOCIATION-CONSTANT; SODIUM-CHLORIDE SOLUTIONS; ACID-MINE DRAINAGE; AQUEOUS-SOLUTION; SURFACE WATERS; SULFURIC-ACID; ELEVATED-TEMPERATURES; ACETATE COMPLEXES; NATURAL-WATERS; LAKE TYRRELL AB The speciation and metal formation quotients for the complexation of aluminum with sulphate were measured based on potentiometric and solubility experiments. Potentiometric titrations, utilizing a hydrogen-electrode concentration cell, were performed from 50 to 125 degrees C at ionic strengths of 0.1, 0.3 and 1.0 molal in aqueous NaCl media. Two aluminum-sulphate species, AlSO4+ and Al(SO4)(2), were identified from the titration data and the formation quotients for these species were modeled by empirical equations to describe their temperature and ionic strength dependencies. Thermodynamic parameters for the complexation reactions were obtained by differentiating the empirical equations with respect to temperature. The thermodynamic quantities obtained for the formation of AlSO4+ at 50 degrees C and infinite dilution are: logK(1) = 3.7 +/- 0.4, Delta H(1)degrees = -10 +/- 30 kJ . mol(-1), Delta S(1)degrees = 40 +/- 100 J . K-1. mol(-1) and Delta C degrees(p1) = 1900 +/- 800 J K-1. mol-1; whereas the values for Al(SO4)(2)(-) are: logK(2) = 5.6 +/- 0.7, Delta H(2)degrees = 10 +/- 50 kJ . mol(-1), Delta S(2)degrees = 100 +/- 100 J . K-1. mol(-1) and Delta C degrees(p2) = 2800 +/- 800 J . K-1. mol(-1). A solubility study, which was undertaken to verify the 50 degrees C polentiometric data, was performed by reacting powdered gibbsite (Al(OH)(3)) with sulphate solutions at 10(-3.5) and 10(-)4 molal H+, total sulphate concentrations from 0.005 to 0.080 molal, and 0.1 and 1.0 molal ionic strength in aqueous NaCl media. The results of the solubility study are in good agreement with the potentiometric data and establish that Al-sulphate complexation substantially enhances the equilibrium solubility of gibbsite. Copyright (C) 1999 Elsevier Science Ltd. C1 Univ Nebraska, Dept Geol, Lincoln, NE 68588 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Ridley, MK (reprint author), Texas Tech Univ, Dept Geosci, POB 41053, Lubbock, TX 79409 USA. NR 67 TC 21 Z9 21 U1 2 U2 5 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 FEB PY 1999 VL 63 IS 3-4 BP 459 EP 472 DI 10.1016/S0016-7037(99)00016-2 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 207ZD UT WOS:000080964900013 ER PT J AU Bierman, PR Marsella, KA Patterson, C Davis, PT Caffee, M AF Bierman, PR Marsella, KA Patterson, C Davis, PT Caffee, M TI Mid-Pleistocene cosmogenic minimum-age limits for pre-Wisconsinan glacial surfaces in southwestern Minnesota and southern Baffin island: a multiple nuclide approach SO GEOMORPHOLOGY LA English DT Article; Proceedings Paper CT Association-of-American-Geographers 92nd Annual Meeting CY APR 09-13, 1996 CL CHARLOTTE, NORTH CAROLINA SP Assoc Amer Geographers DE glaciation; dating; cosmogenic; isotope; Quaternary ID PRODUCTION-RATES; EXPOSURE AGES; INSITU; BE-10; EROSION; AL-26; LANDSCAPES; WORKSHOP; HISTORY; ROCKS AB Paired Be-10 and Al-26 analyses (n = 14) indicate that pre-Wisconsinan, glaciated bedrock surfaces near the northern (Baffin Island) and southern (Minnesota) paleo-margins of the Laurentide Ice Sheet have long and complex histories of cosmic-ray exposure, including significant periods of partial or complete shielding from cosmic rays. Using the ratio, Al-26/Be-10, we calculate that striated outcrops of Sioux Quartzite in southwestern Minnesota (southern margin) were last overrun by ice at least 500,000 years ago. Weathered bedrock tors on the once-glaciated uplands of Baffin Island (northern margin) are eroding no faster than 1.1 m Myr(-1), the equivalent of at least 450,000 years of surface and near-surface exposure. Our data demonstrate that exposure ages and erosion rates calculated from single nuclides can underestimate surface stability dramatically because any intermittent burial, and the resultant lowering of nuclide production rates and nuclide abundances, will remain undetected. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Vermont, Dept Geol, Burlington, VT 05405 USA. Univ Minnesota, Minnesota Geol Survey, St Paul, MN 55114 USA. Bentley Coll, Dept Nat Sci, Waltham, MA 02454 USA. Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94550 USA. Univ Calif Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. RP Bierman, PR (reprint author), Univ Vermont, Dept Geol, Burlington, VT 05405 USA. RI Caffee, Marc/K-7025-2015 OI Caffee, Marc/0000-0002-6846-8967 NR 31 TC 168 Z9 175 U1 0 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-555X J9 GEOMORPHOLOGY JI Geomorphology PD FEB PY 1999 VL 27 IS 1-2 BP 25 EP 39 DI 10.1016/S0169-555X(98)00088-9 PG 15 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 169VD UT WOS:000078769000004 ER PT J AU Hancock, GS Anderson, RS Chadwick, OA Finkel, RC AF Hancock, GS Anderson, RS Chadwick, OA Finkel, RC TI Dating fluvial terraces with Be-10 and Al-26 profiles: application to the Wind River, Wyoming SO GEOMORPHOLOGY LA English DT Article; Proceedings Paper CT Association-of-American-Geographers 92nd Annual Meeting CY APR 09-13, 1996 CL CHARLOTTE, NORTH CAROLINA SP Assoc Amer Geographers DE fluvial terraces; inheritance-correction technique; cosmogenic radionuclide ID IN-SITU BE-10; BULL LAKE; PINEDALE GLACIATIONS; COSMOGENIC NUCLIDES; RANGE; SURFACES; DEPOSITS; EROSION; RATES; CHRONOLOGY AB Fluvial strath terraces provide a record of river incision and the timing of climatic perturbations to the fluvial system. Dating depositional surfaces like terraces that are older than the range of C-14, however, is difficult. We employ a cosmogenic radionuclide (CRN) profile technique that addresses a major problem of CRN dating on such surfaces: nuclide inheritance. By measuring Be-10 and Al-26 profiles, we constrain the exposure age and the mean CRN inheritance for the deposit. The CRN profile also yields a self-check on the assumptions underlying the method. Pie report our attempts to date terraces along the Wind River, WY. Like many sequences of western North American fluvial terraces, these are inferred to reflect oscillation between glacial and interglacial conditions in the headwaters. Previous dating of some of these terraces and the associated terraces and glacial deposits makes this a unique location to compare dating methods. Dates from five sites along the Bull Lake-glacial correlative terrace (WR-3) are similar to 118-125 ka, which agrees with dates on Bull Lake-age moraines and independent age estimates on the terrace, and is consistent with the model of terrace-glacial relationship. CRN inheritance is significant and highly variable, requiring it be considered despite the additional sampling complexity. Assuming all inheritance in WR-3 deposits arises during exhumation in the headwaters, we obtain minimum mean rates of exhumation of similar to 13-130 m/My for the source rocks. Alternatively, assuming the CRNs are inherited during clast transport, the time of fluvial transport from source to terrace is > similar to 10 ka; it increases downstream and is lower for sand than cobbles. The CRN ages for older terraces (WR-7 = similar to 300 ka and WR-15 = similar to 510 ka) are lower by similar to 50% than previous estimates based on tephrochronology; the most plausible explanation is eolian deflation of a once thicker loess cover on the terrace surfaces. Mean thicknesses of loess of similar to 0.5-1.5 m are required to reconcile these concentrations of CRN with the previous estimates of age. Difficulty in dating the older terraces emphasizes that geologic caution, independent estimates of age, and multiple sample sites should still be part of dating depositional surfaces with CRNs, even when employing the inheritance-correction technique. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Santa Cruz, Dept Earth Sci, Santa Cruz, CA 95064 USA. Univ Calif Santa Cruz, Inst Tecton, Santa Cruz, CA 95064 USA. Univ Calif Santa Barbara, Dept Geog, Santa Barbara, CA 93106 USA. Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94550 USA. RP Hancock, GS (reprint author), Coll William & Mary, Dept Geol, Williamsburg, VA 23187 USA. EM gshanc@facstaff.wm.edu RI Hancock, Gregory/I-7310-2012 NR 42 TC 122 Z9 133 U1 2 U2 28 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-555X J9 GEOMORPHOLOGY JI Geomorphology PD FEB PY 1999 VL 27 IS 1-2 BP 41 EP 60 DI 10.1016/S0169-555X(98)00089-0 PG 20 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 169VD UT WOS:000078769000005 ER PT J AU Heimsath, AM Dietrich, WE Nishiizumi, K Finkel, RC AF Heimsath, AM Dietrich, WE Nishiizumi, K Finkel, RC TI Cosmogenic nuclides, topography, and the spatial variation of soil depth SO GEOMORPHOLOGY LA English DT Article; Proceedings Paper CT Association-of-American-Geographers 92nd Annual Meeting CY APR 09-13, 1996 CL CHARLOTTE, NORTH CAROLINA SP Assoc Amer Geographers DE geomorphology; cosmogenic nuclides; soil production; erosion; landscape evolution ID SAN-FRANCISCO BAY; EROSION RATES; NEW-ZEALAND; CALIFORNIA; EVOLUTION; LANDSCAPE; EQUILIBRIUM; HILLSLOPE; SEDIMENT; MODEL AB If the rate of bedrock conversion to a mobile layer of soil depends on the local thickness of soil, then hillslopes on uniform bedrock in a landscape approaching dynamic equilibrium should be mantled by a uniform thickness of soil. Conversely, if the depth of soil varies across an actively eroding landscape, then rates of soil production will also vary and, consequently the landscape will not be in morphologic equilibrium. The slow evolution of hillslopes relative to the tempo of climatic variations and tectonic adjustments would suggest that local morphologic disequilibrium may be expected in many landscapes. Here, we explore this issue of equilibrium landscapes through a previously developed model that predicts the spatial variation in thickness of soil as a consequence of the local balance between soil production and erosion. First, we confirm the assumption in the model that soil production varies inversely with the thickness of soil using two independent methods. One method uses the theoretical prediction that at local steady state (soil production equals removal), the depth of soil should vary inversely with hillslope curvature. The second method relies on direct measurements of in situ produced concentrations of cosmogenic Be-10 and Al-26 in bedrock at the base of the soil column. For our study site in Northern California, the two methods agree and yield the expression that the rate of soil production declines exponentially with the thickness of soil from 0.077 mm/year with no soil mantle to 0.0077 mm/year under 1 m of soil. We then use this function of soil production in a coupled production and diffusive model of sediment transport to explore the controls on the spatial variation of the depth of soil on four separate spur ridges (noses) where we measured the data for the function of soil production. Model predictions are sensitive to boundary conditions, grid scale, and run time. Nonetheless, we found good agreement between predicted and observed depths of soil as long as we used the observed function of soil production. The four noses each have spatially varying curvature and, consequently, have varying depths of soil, implying morphologic disequilibrium. We suggest that our study site has been subjected to a wave of incision and varying intensities of erosion because of tectonic and climatic oscillations that have a frequency shorter than the morphologic response time of the landscape. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Geol & Geophys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94550 USA. RP Heimsath, AM (reprint author), Univ Calif Berkeley, Dept Geol & Geophys, Berkeley, CA 94720 USA. NR 68 TC 185 Z9 187 U1 5 U2 43 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-555X J9 GEOMORPHOLOGY JI Geomorphology PD FEB PY 1999 VL 27 IS 1-2 BP 151 EP 172 DI 10.1016/S0169-555X(98)00095-6 PG 22 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 169VD UT WOS:000078769000011 ER PT J AU Weber, RJ McMurry, PH Mauldin, RL Tanner, DJ Eisele, FL Clarke, AD Kapustin, VN AF Weber, RJ McMurry, PH Mauldin, RL Tanner, DJ Eisele, FL Clarke, AD Kapustin, VN TI New particle formation in the remote troposphere: A comparison of observations at various sites SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SULFURIC-ACID; NUCLEATION; CLOUDS; AEROSOL AB Measurements show that new particles are formed by homogenous nucleation over a wide range of conditions in the remote troposphere. In our studies, large nucleation events are found exclusively in regions of enhanced sulfuric acid vapor (H2SO4g)concentrations, with maximum concentrations never exceeding 5x10(7) molecules cm(-3). Although these data suggest that H2SO4g participated, comparisons between ambient conditions in regions of nucleation to conditions necessary for binary H2SO4 water (H2O) nucleation indicate that the mechanism may vary with elevation. In remote marine regions, at altitudes greater than similar to 4 km above sea level, observations of nucleation in clear air along cloud perimeters are in fair agreement with current classical binary nucleation models. In these regions, the low temperatures associated with high altitudes may produce sufficiently saturated H2SO4 for the production of new H2SO4/H2O particles. However, uncertainties with current binary nucleation models limit decisive comparisons. In warmer regions, closer to the earth's surface, measured H2SO4 concentrations are clearly insufficient for binary nucleation. Conditions at these sites are similar to those observed in an earlier study where there was circumstantial evidence for a ternary mechanism involving H2SO4, H2O, and ammonia (NH3) [Weber et al., 1998], suggesting that this may be a significant route for particle production at lower altitudes where surface-derived species, like NH3, are more apt to participate. C1 Brookhaven Natl Lab, Dept Appl Sci, Environm Chem Div, Upton, NY 11973 USA. Univ Minnesota, Particle Technol Lab, Minneapolis, MN USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. RP Weber, RJ (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Environm Chem Div, Upton, NY 11973 USA. RI McMurry, Peter/A-8245-2008 OI McMurry, Peter/0000-0003-1609-5131 NR 22 TC 182 Z9 187 U1 9 U2 40 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 FEB 1 PY 1999 VL 26 IS 3 BP 307 EP 310 DI 10.1029/1998GL900308 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 163YK UT WOS:000078434300007 ER PT J AU Sergeev, VA Liou, K Meng, CI Newell, PT Brittnacher, M Parks, G Reeves, GD AF Sergeev, VA Liou, K Meng, CI Newell, PT Brittnacher, M Parks, G Reeves, GD TI Development of auroral streamers in association with localized impulsive injections to the inner magnetotail SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PLASMA SHEET; MAGNETOSPHERE; EXPANSION; PARTICLE; FLOWS AB During continuous magnetospheric activity it is not uncommon to observe narrow (in MLT) transient particle injections (duration about 1-2 minute at E = 100 keV and local time extent less than or equal to 1 hour MLT) in the nightside part of geosynchronous orbit. Using global UV images from POLAR spacecraft we analyze the development of auroral activity on December 22, 1996 during a sequence of such injections observed by two LANL spacecraft. We found that narrow transient injections are associated with specific localized auroral form, the auroral streamer, which develops in this local time sector. The streamer first appear as a bright spot in the poleward part of the double oval approximate to 2-5 minutes before the geosynchronous plasma injection, and then develops equatorward, reaching in many cases the equatorward boundary of the UV aurora. We interprete the observations as evidence that some high speed flow bursts (BBFs) of small cross-tail extent (less than 1 h MLT), formed in the distant tail or midtail, can intrude as close to the Earth as the geosynchronous distance before being stopped. C1 St Petersburg State Univ, Inst Phys, St Petersburg 198904, Russia. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Univ Washington, Div Space Sci, Geophys Program, Seattle, WA 98195 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Sergeev, VA (reprint author), St Petersburg State Univ, Inst Phys, St Petersburg 198904, Russia. EM sergeev1@snoopy.phys.spbu.ru RI Reeves, Geoffrey/E-8101-2011; Sergeev, Victor/H-1173-2013; Liou, Kan/C-2089-2016 OI Reeves, Geoffrey/0000-0002-7985-8098; Sergeev, Victor/0000-0002-4569-9631; Liou, Kan/0000-0001-5277-7688 NR 15 TC 109 Z9 109 U1 0 U2 3 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 FEB 1 PY 1999 VL 26 IS 3 BP 417 EP 420 DI 10.1029/1998GL900311 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 163YK UT WOS:000078434300035 ER PT J AU Gavrilin, YI Khrouch, VT Shinkarev, SM Krysenko, NA Skryabin, AM Bouville, A Anspaugh, LR AF Gavrilin, YI Khrouch, VT Shinkarev, SM Krysenko, NA Skryabin, AM Bouville, A Anspaugh, LR TI Chernobyl accident: Reconstruction of thyroid dose for inhabitants of the Republic of Belarus SO HEALTH PHYSICS LA English DT Article DE Chernobyl; I-131; I-129; thyroid AB The Chernobyl accident in April 1986 resulted in widespread contamination of the environment with radioactive materials, including I-131 and other radioiodines, This environmental contamination led to substantial radiation doses in the thyroids of many inhabitants of the Republic of Belarus, The reconstruction of thyroid doses received by Belarussians is based primarily on exposure rates measured against the neck of more than 200,000 people in the more contaminated territories; these measurements were carried out within a few weeks after the accident and before the decay of I-131 to negligible levels. Preliminary estimates of thyroid dose have been divided into 3 classes: Class 1 ("measured" doses), Class 2 (doses "derived by affinity"), and Class 3 ("empirically-derived" doses), Class 1 doses are estimated directly from the measured thyroidal I-131 content of the person considered, plus information on lifestyle and dietary habits. Such estimates are available for about 130,000 individuals from the contaminated areas of the Gomel and Mogilev Oblasts and from the city of Minsk, Maximum individual doses are estimated to range up to about 60 Gy, For every village with a sufficient number of residents with Class 1 doses, individual thyroid dose distributions are determined for several age groups and levels of milk consumption. These data are used to derive Class 2 thyroid dose estimates for unmeasured inhabitants of these villages. For any village where the number of residents with Class 1 thyroid doses is small or equal to zero, individual thyroid doses of Class 3 are derived from the relationship obtained between the mean adult thyroid dose and the deposition density of I-131 Cs-137 in villages with Class 2 thyroid doses presenting characteristics similar to those of the village considered. In order to improve the reliability of the Class 3 thyroid doses, an extensive program of measurement of I-129 in soils is envisaged. C1 Minist Publ Hlth Russia, Inst Biophys, State Res Ctr Russia, Moscow, Russia. Minist Publ Hlth, Gomel, Byelarus. Sci Res Inst Radiat Med, Gomel Branch, Gomel, Byelarus. NCI, Radiat Effects Branch, Bethesda, MD 20892 USA. Lawrence Livermore Natl Lab, Dose Reconstruct Program, Livermore, CA 94550 USA. NR 34 TC 53 Z9 55 U1 0 U2 3 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD FEB PY 1999 VL 76 IS 2 BP 105 EP 119 DI 10.1097/00004032-199902000-00002 PG 15 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 161AR UT WOS:000078266000001 PM 9929121 ER PT J AU Cheng, YS Snipes, MB Wang, YS Jow, HN AF Cheng, YS Snipes, MB Wang, YS Jow, HN TI Biokinetics and dosimetry of titanium tritide particles in the lung SO HEALTH PHYSICS LA English DT Article DE biokinetics; tritium; lungs; human; dose; absorbed ID METABOLISM AB Doses of internal radiation from inhalation of metal tritide aerosols are potentially a major radiation protection problem encountered by nuclear industry workers. Based on results of experiments,with rats intratracheally instilled with titanium tritide particles and on a self-absorption factor of beta particles determined by a numerical method, a biokinetic model was developed for inhaled particles of titanium tritide, Results show ed that lung burdens of the tritide are well represented by a two-component exponential equation; biological half-lives derived for the retention of H-3 in lung where 0.81 d and 66 d, The tritium clearance rate, ia urine or feces was described by bi-phase exponential components. At 121 d after instillation, 82% of the initial lung burden of H-3 had been eliminated, of which 37% was excreted in urine, 29% via feces, and 16% through exhaled air. Based on simulation results of the biokinetic model, the cumulative absorbed dose and committed effective dose were calculated as well as the annual limit of intake (ALI) and derived air concentration (DAC), The ALI and DAC values for titanium tritide were a factor of 5 lower than values for tritiated water. This information will be useful in developing new guidelines for radiation protection purposes. C1 Lovelace Resp Res Inst, Albuquerque, NM 87185 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. NR 20 TC 17 Z9 17 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 FEB PY 1999 VL 76 IS 2 BP 120 EP 128 DI 10.1097/00004032-199902000-00003 PG 9 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 161AR UT WOS:000078266000002 PM 9929122 ER PT J AU Reichelt, R Clay, M Eichorst, J AF Reichelt, R Clay, M Eichorst, J TI Techniques for measuring radiographic repeat rates - Reply SO HEALTH PHYSICS LA English DT Letter C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD FEB PY 1999 VL 76 IS 2 BP 196 EP 196 PG 1 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 161AR UT WOS:000078266000013 ER PT J AU Parks, BS AF Parks, BS TI Tritium dose overestimates by CAP88-PC SO HEALTH PHYSICS LA English DT Article DE operational topics; tritium; dose assessment; food chain AB The dose assessment software CAP88-PC may overestimate doses from tritium under some conditions. The overestimates are linked to three key assumptions implicit in the software that may not be immediately apparent. The three assumptions are (1) the contribution of home grown food (2) the distances at which food is produced anti (3) the number of people consuming locally produced food. C1 US DOE, Off Energy Res, Germantown, MD 20874 USA. NR 4 TC 2 Z9 2 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 FEB PY 1999 VL 76 IS 2 SU S BP S37 EP S38 DI 10.1097/00004032-199902001-00010 PG 2 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 162HL UT WOS:000078339900008 PM 9930839 ER PT J AU Schischmanoff, PO Cynober, T Mielot, F Leclerc, L Vasseur-Godbillon, C Baudin-Creuza, V Magowan, C Yeung, J Mohandas, N Tchernia, G Delaunay, J AF Schischmanoff, PO Cynober, T Mielot, F Leclerc, L Vasseur-Godbillon, C Baudin-Creuza, V Magowan, C Yeung, J Mohandas, N Tchernia, G Delaunay, J TI Southeast Asian ovalocytosis in white persons SO HEMOGLOBIN LA English DT Article DE Southeast Asian ovalocytosis (SAO); White persons; stomatocytes; ovalo-stomatocytes ID HUMAN-ERYTHROCYTE MEMBRANE; BAND-3 PROTEIN; HEREDITARY OVALOCYTOSIS; CYTOPLASMIC DOMAIN; MOLECULAR-BASIS; MALARIA; GENE; POLYMORPHISM; RESISTANT; SUBUNITS AB We describe two White persons, a girl and her mother, presenting with Southeast Asian ovalocytosis. The child was evaluated for scoliosis. The red cell indices were normal but the cell counter triggered an alarm due to a high fraction of hyperdense red cells. Blood smears showed ovalocytes and ovalostomatocytes. Red cells exhibited a total lack of deformability upon osmotic gradient ektacytometry performed immediately after blood drawing. Analysis of nucleic acids and proteins ascertained a 27 nucleotide deletion, resulting in the loss of amino acids 400 to 408, and the presence in cis of the Memphis I polymorphism. The sulfate transport was diminished by more than 50%. There was no acidosis. In vitro invasion of ovalocytes by Plasmodium falciparum was decreased. The mother presented with the same hematological picture. On the whole, the condition was Southeast Asian ovalocytosis in all respects. The present kindred had ancestors who had inhabited islands in the Southwestern Indian Ocean. C1 Assistance Publ Hop Paris, Hop Bicetre, Serv Biochim 1, F-94275 Le Kremlin Bicetre, France. Assistance Publ Hop Paris, Hop Bicetre, Serv Hematol Immunol & Cytogenet, F-94275 Le Kremlin Bicetre, France. Assistance Publ Hop Paris, Hop Bicetre, INSERM, U473, F-94275 Le Kremlin Bicetre, France. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Schischmanoff, PO (reprint author), Hop Bicetre, Lab Biochim 1, 78 Rue Gen Leclerc, F-94275 Le Kremlin Bicetre, France. EM delaunay@kb.inserm.fr NR 26 TC 4 Z9 4 U1 0 U2 0 PU MARCEL DEKKER INC PI NEW YORK PA 270 MADISON AVE, NEW YORK, NY 10016 USA SN 0363-0269 J9 HEMOGLOBIN JI Hemoglobin PD FEB PY 1999 VL 23 IS 1 BP 47 EP 56 PG 10 WC Biochemistry & Molecular Biology; Hematology SC Biochemistry & Molecular Biology; Hematology GA 171FK UT WOS:000078851900004 PM 10081985 ER PT J AU Zajic, V Thieberger, P AF Zajic, V Thieberger, P TI Heavy ion linear energy transfer measurements during single event upset testing of electronic devices SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article DE heavy ion beam; Linear energy transfer (LET); plastic scintillator; pulse height defect (PHD); single-event upset (SEU) AB A heavy ion beam diagnostic system installed at the Brookhaven Single Event Upset Test Facility is described. Calibration of the system with the help of a-particles, essential for linear energy transfer (LET) measurements, is discussed, Measured LET values for 20 different ions, including Li-7, B-9, C-12, O-16, F-19, Si-28, S-32, Cl-35, Ca-40, Sc-45, Ti-48, Fe-56, Ni-58, Cu-63, Ge-74, Br-79, Ag-107, I-127, Au-197, and U-235, with energies between 0.5 and 8.5 MeV/AMU but not exceeding 400 MeV for the heaviest ions, are presented in both graphical and numerical forms. Results are compared to predictions of the TRIM-90 simulation program, with an average difference between the measured and calculated values of 2 +/- 6%. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. RP Zajic, V (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. NR 10 TC 15 Z9 16 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD FEB PY 1999 VL 46 IS 1 BP 59 EP 69 DI 10.1109/23.747768 PG 11 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 169VP UT WOS:000078770000008 ER PT J AU Keiter, ER Kushner, MJ AF Keiter, ER Kushner, MJ TI Radical and electron densities in a high plasma density-chemical vapor deposition reactor from a three-dimensional simulation SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE gas discharges; plasma CVD; plasma materials-processing applications AB High plasma density chemical vapor deposition (HPD-CVD) is being developed for producing interlevel dielectrics in microelectronics fabrication, We present images of radical and electron densities in an Ar/SiH4 HPD-CVD inductively coupled reactor produced by a three-dimensional equipment model. The silane feedstock and silyl (SiH3) radicals are rapidly dissociated, resulting is densities which are maximum near the nozzles, The silylene (SiH2) radicals, the most fragmented species included in the simulation, are the most uniformly distributed. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Illinois, Dept Elect & Comp Engn, Urbana, IL 61801 USA. RP Keiter, ER (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. RI Kushner, Mark/A-7362-2008; Kushner, Mark/D-4547-2015 NR 2 TC 2 Z9 2 U1 1 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1999 VL 27 IS 1 BP 62 EP 63 DI 10.1109/27.763037 PG 2 WC Physics, Fluids & Plasmas SC Physics GA 197MX UT WOS:000080369700030 ER PT J AU Tuszewski, M AF Tuszewski, M TI Planar inductively coupled plasmas operated with low and high radio frequencies SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE inductively coupled plasmas AB Planar inductively coupled plasmas (ICP's) powered with 13.56 MHz radio frequency (RF) are used increasingly by the semiconductor industry for close-coupled etching processes, Two planar ICP's operated with 0.46 and 13.56 MHz RF are described. Low-pressure argon discharges are compared in the same vacuum chamber. The two planar ICP's generate nearly identical plasmas, within experimental uncertainties, for similar gas pressures and RF powers. The ICP operation proves significantly easier with low RF frequency. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Tuszewski, M (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 6 TC 10 Z9 10 U1 3 U2 9 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1999 VL 27 IS 1 BP 68 EP 69 DI 10.1109/27.763041 PG 2 WC Physics, Fluids & Plasmas SC Physics GA 197MX UT WOS:000080369700033 ER PT J AU Czarnetzki, U Hebner, GA Luggenholscher, D Dobele, HF Riley, ME AF Czarnetzki, U Hebner, GA Luggenholscher, D Dobele, HF Riley, ME TI Plasma sheath electric field strengths above a grooved electrode in a parallel-plate radio-frequency discharge SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE electric fields; plasma; Rydberg; sheath AB The magnitude of the sheath electric field above a grooved electrode was measured using a novel, two color, laser induced fluorescence technique. Spatially resolved electric fields in the sheath region were determined by mapping the field induced Stark splitting of the n = 14 level in atomic hydrogen. Measured electric field values are in good agreement with calculated values. C1 Univ Essen Gesamthsch, Inst Laser & Plasmaphys, D-45117 Essen, Germany. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Czarnetzki, U (reprint author), Univ Essen Gesamthsch, Inst Laser & Plasmaphys, D-45117 Essen, Germany. NR 3 TC 21 Z9 22 U1 1 U2 6 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1999 VL 27 IS 1 BP 70 EP 71 DI 10.1109/27.763042 PG 2 WC Physics, Fluids & Plasmas SC Physics GA 197MX UT WOS:000080369700034 ER PT J AU Anders, A MacGill, RA Rubin, M AF Anders, A MacGill, RA Rubin, M TI Evaluation of the plasma distribution of a quasi-linear constricted plasma source SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE constricted plasma source; gas plasma flow; plasma diagnostics; plasma processing of materials ID HOLLOW AB The quasi-linear constricted plasma source is a downstream plasma source with ten linearly aligned discharge cells, Each cell operates on the basis of a constricted glow discharge, The plasma output can easily be monitored by the plasma-emitted light, The information is not only intuitive but can also be used to operate on-line feedback control of the plasma source which is important for large area plasma processing of materials. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Anders, A (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RI Anders, Andre/B-8580-2009 OI Anders, Andre/0000-0002-5313-6505 NR 9 TC 6 Z9 6 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 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1999 VL 27 IS 1 BP 82 EP 83 DI 10.1109/27.763051 PG 2 WC Physics, Fluids & Plasmas SC Physics GA 197MX UT WOS:000080369700040 ER PT J AU Keiter, ER Booske, JH Hitchon, WNG AF Keiter, ER Booske, JH Hitchon, WNG TI Visualization of plasma source ion implantation for arrays of multiple targets SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE ion implantation; PSII; pulsed sheaths ID MODEL AB Visualization of sheath overlap dynamics during plasma source ion implantation (PSII) of a multiple-target array is used to illustrate the effect of target spacing on dose uniformity over the surface of a single target. The simulations are conducted using a hybrid plasma model, and the images are created using the Tecplot package by Amtec. The simulations suggest scaling rules for sheath overlap time as a function of target spacing. C1 Univ Illinois, Dept Elect & Comp Engn, Urbana, IL 61801 USA. Univ Wisconsin, Dept Elect & Comp Engn, Madison, WI 53706 USA. RP Keiter, ER (reprint author), Sandia Natl Labs, Albuquerque, NM 87108 USA. NR 6 TC 1 Z9 1 U1 1 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1999 VL 27 IS 1 BP 86 EP 87 DI 10.1109/27.763054 PG 2 WC Physics, Fluids & Plasmas SC Physics GA 197MX UT WOS:000080369700042 ER PT J AU Maqueda, RJ Wurden, GA AF Maqueda, RJ Wurden, GA TI Images of plasma disruption effects in the tokamak fusion test reactor SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE digital systems; magnetic confinement; optical imaging; plasmas; tokamaks ID TFTR AB Fast-framing imaging of visible radiation from magnetically confined plasmas has lately become a useful tool for both machine operation and physics studies. Using an intensified, commercial Kodak Ektapro imaging system, the effects of a plasma disruption were observed in the Tokamak Fusion Test Reactor (TFTR). The high-energy "runaway" electrons created soon after the disruption collide with the plasma facing components damaging this surface and producing a shower of debris that traverses the toroidal vessel and "falls" over the inner bumper limiter. C1 Univ Calif Los Alamos Natl Lab, Plasma Phys Grp, Los Alamos, NM 87545 USA. RP Maqueda, RJ (reprint author), Univ Calif Los Alamos Natl Lab, Plasma Phys Grp, Los Alamos, NM 87545 USA. RI Wurden, Glen/A-1921-2017 OI Wurden, Glen/0000-0003-2991-1484 NR 4 TC 2 Z9 2 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1999 VL 27 IS 1 BP 112 EP 113 DI 10.1109/27.763073 PG 2 WC Physics, Fluids & Plasmas SC Physics GA 197MX UT WOS:000080369700055 ER PT J AU Spong, DA Hirshman, SP Whitson, JC AF Spong, DA Hirshman, SP Whitson, JC TI Optimization and visualization of low aspect ratio stellarators SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE magnetic confinement; optimization methods; plasma confinement; plasmas; scientific visualization; stellarators ID DEVICES AB Improved tools have recently been developed for numerically designing low aspect ratio stellarator plasma confinement devices. The increased flexibility offered by three-dimensional magnetic flux surface shaping has allowed a range of physics targets such as improved confinement and plasma stability to be achieved in relatively compact (low aspect ratio) devices. Three-dimensional scientific visualization has been a useful tool for developing understanding and intuition in this effort. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37830 USA. RP Spong, DA (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37830 USA. RI Spong, Donald/C-6887-2012 OI Spong, Donald/0000-0003-2370-1873 NR 4 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 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1999 VL 27 IS 1 BP 116 EP 117 DI 10.1109/27.763077 PG 2 WC Physics, Fluids & Plasmas SC Physics GA 197MX UT WOS:000080369700057 ER PT J AU Wan, AS Barbee, TW Cauble, R Celliers, P Da Silva, LB Moreno, JC Rambo, PW Stone, GF Trebes, JE Weber, F AF Wan, AS Barbee, TW Cauble, R Celliers, P Da Silva, LB Moreno, JC Rambo, PW Stone, GF Trebes, JE Weber, F TI A soft X-ray laser interferogram of a high-density colliding plasma SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE collision processes; inertial confinement; interferometry; X-ray lasers AB We have used a soft X-ray laser interferometer to study the collision and subsequent interaction of counterstreaming high-density plasmas. The measured density profiles show the evolution of the colliding plasmas from interpenetration, when the low-density edge of the plasmas first collide, to stagnation at the symmetry plane with density building at the symmetry plane. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Wan, AS (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 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 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1999 VL 27 IS 1 BP 120 EP 121 DI 10.1109/27.763079 PG 2 WC Physics, Fluids & Plasmas SC Physics GA 197MX UT WOS:000080369700059 ER PT J AU Voss, SA Barnes, CW Oertel, JA Watt, RG Boehly, TR Bradley, DK Knauer, JP Pien, G AF Voss, SA Barnes, CW Oertel, JA Watt, RG Boehly, TR Bradley, DK Knauer, JP Pien, G TI Gated X-ray framing camera image of a direct-drive cylindrical implosion SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE hydrodynamics; imaging mapping; inertial confinement; X-ray measurements AB Gated X-ray images of laser-driven implosions can provide movies of typically 16 frames with similar to 80 ps time resolution and 10 mu m spatial resolution, Cylindrical implosions allow study of convergent hydrodynamics but with excellent diagnostic access down the axis of the cylinder, This example from a recent cylindrical implosion campaign on the OMEGA laser provides quantitative data on the growth of ablative Rayleigh-Taylor instabilities in convergent geometry. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Rochester, Laser Energet Lab, Rochester, NY 14623 USA. RP Barnes, CW (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 4 TC 0 Z9 0 U1 1 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1999 VL 27 IS 1 BP 132 EP 133 DI 10.1109/27.763088 PG 2 WC Physics, Fluids & Plasmas SC Physics GA 197MX UT WOS:000080369700065 ER PT J AU Wurden, GA Wurden, AJ Gladstone, IM AF Wurden, GA Wurden, AJ Gladstone, IM TI Plasma tails: Comets Hale-Bopp and Hyakutake SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article AB Comet Hale-Bopp was one of the largest comets ever recorded, and it exhibited both a massive dust tail and a plasma tail, which developed as it approached the sun over the course of six months in 1996-1997, Because the dust responds to gravity and light pressure, but plasmas also respond to the local solar wind (Coulomb collisions and magnetic fields), there is typically an angular separation between the two tails, as seen in the photo above. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Los Alamos High Sch, Los Alamos, NM 87544 USA. RP Wurden, GA (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Wurden, Glen/A-1921-2017 OI Wurden, Glen/0000-0003-2991-1484 NR 4 TC 2 Z9 2 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1999 VL 27 IS 1 BP 142 EP 143 DI 10.1109/27.763094 PG 2 WC Physics, Fluids & Plasmas SC Physics GA 197MX UT WOS:000080369700070 ER PT J AU Gilgenbach, RM Kovaleski, SD Lash, JS Ang, LK Lau, YY AF Gilgenbach, RM Kovaleski, SD Lash, JS Ang, LK Lau, YY TI Science and applications of energy beam ablation SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE ablation; e-beam; laser-ablation ID RESONANT HOLOGRAPHIC-INTERFEROMETRY; LASER-ABLATION; ABSORPTION PHOTOGRAPHY; PLASMA ENVIRONMENTS; ION-SOURCE; DYNAMICS; ALUMINUM; GAS; SURFACE; PLUMES AB This article reviews the advances in the science and applications of energy beam ablation of materials at the University of Michigan. Types of energy beams applied to materials ablation are: excimer lasers, laser-ablation-assisted plasma discharges, and channelspark electron beams. The characteristics of the ablation plasma plumes generated by these energy deposition sources are discussed and compared. Plume expansion velocities are in the range of cm/mu s for all three types of ablation plumes. Electron beam ablation plumes show higher ionization states than laser ablation plumes. C1 Univ Michigan, Nucl Engn & Radiol Sci Dept, Intense Energy Beam Interact Lab, Ann Arbor, MI 48109 USA. Sandia Natl Labs, Albuquerque, NM 87123 USA. RP Gilgenbach, RM (reprint author), Univ Michigan, Nucl Engn & Radiol Sci Dept, Intense Energy Beam Interact Lab, Ann Arbor, MI 48109 USA. RI ANG, Lay Kee/F-8115-2015; OI ANG, Lay Kee/0000-0003-2811-1194; Kovaleski, Scott/0000-0002-5831-6388 NR 31 TC 17 Z9 17 U1 2 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1999 VL 27 IS 1 BP 150 EP 158 DI 10.1109/27.763103 PG 9 WC Physics, Fluids & Plasmas SC Physics GA 197MX UT WOS:000080369700074 ER PT J AU Bilek, MMM Brown, IG AF Bilek, MMM Brown, IG TI The effects of transmission through a magnetic filter on the ion charge state distribution of a cathodic vacuum arc plasma SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE filtered cathodic vacuum arc; ion charge states; 90 degrees filter; time of flight spectroscopy ID MACROPARTICLE FILTERS; TRANSPORT; STRAIGHT AB In this paper we report the effects of transmission through a 90 degrees solenoidal magnetic filter on the ion charge state distribution of a vacuum are plasma as a function of the magnetic field strength and the injection distance between the cathode and filter entrance. The mean ion charge state, measured using the time of flight technique, increased compared with the unfiltered value at low magnetic fields and then steadily decreased as the filter field was increased. At high fields, it was significantly lower than the unfiltered value. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Bilek, MMM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 17 TC 15 Z9 15 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1999 VL 27 IS 1 BP 193 EP 198 DI 10.1109/27.763115 PG 6 WC Physics, Fluids & Plasmas SC Physics GA 197MX UT WOS:000080369700079 ER PT J AU Trudnowski, DJ Johnson, JM Hauer, JF AF Trudnowski, DJ Johnson, JM Hauer, JF TI Making prony analysis more accurate using multiple signals SO IEEE TRANSACTIONS ON POWER SYSTEMS LA English DT Article DE prony analysis; electromechanical oscillations ID SYSTEM RESPONSE SIGNALS; ORDER; MODELS; DESIGN; INTERAREA; REDUCTION AB Prony analysis has proven to be a valuable tool in estimating the modal content of power oscillations from measured ringdowns. The accuracy of the mode estimates is limited by the noise content always found in field measured signals. current Prony analysis methods assume the system to be single output, and individual signals are analyzed independently often resulting in conflicting frequency and damping estimates (due to noise effects). This paper considers a simple extension to Prony analysis that allows multiple signals to be analyzed simultaneously resulting in one set of mode estimates. Examples are used to show that this extension improves the accuracy of modal estimates and simplifies the analysis steps. The first example uses a Monte Carlo type simulation model and the second analyzes field measured data from the western North American power system. C1 Univ Montana, Montana Tech, Butte, MT 59701 USA. Pacific NW Natl Lab, Richland, WA USA. RP Trudnowski, DJ (reprint author), Univ Montana, Montana Tech, Butte, MT 59701 USA. NR 22 TC 121 Z9 156 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 0885-8950 J9 IEEE T POWER SYST JI IEEE Trans. Power Syst. PD FEB PY 1999 VL 14 IS 1 BP 226 EP 231 DI 10.1109/59.744537 PG 6 WC Engineering, Electrical & Electronic SC Engineering GA 162YF UT WOS:000078374500041 ER PT J AU Brown, RG Brost, RC AF Brown, RG Brost, RC TI A 3-D modular gripper design tool SO IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION LA English DT Article DE agile manufacturing; fixture planning; force closure; grasp planning; manipulation ID FIXTURES; GRASPS AB Modular fixturing kits are sets of components used for flexible, rapid construction of fixtures. A modular vise is a parallel-jaw vise, with a regular grid of precisely positioned holes on each jaw. Parts are held by plating pins in the holes so that when the vise is closed, the part is reliably located and completely constrained. The modular vise concept can be adapted easily to the design of modular parallel-jaw grippers for robots. By attaching a grid-plate to each jaw of a parallel-jaw gripper, we gain the ability to easily construct high-quality grasps for a wide variety of parts from a standard set of hardware, Wallack and Canny [29], [30] developed an algorithm for planning planar grasp configurations for the modular vise. In this paper, we expand this work to produce a three dimensional (3-D) fisture/gripper design tool. We describe several anal,ses we have added to the planar algorithm, including a 3-D grasp quality metric based on force information, 3-D geometric loading analysis, and inter-gripper interference analysis. Finally, we describe two applications of our code. One of these is an internal application at Sandia, while the other shows a potential use of our code for designing part of an agile assembly line. C1 Sandia Natl Labs, Intelligent Syst & Robot Ctr, Albuquerque, NM 87185 USA. RP Sandia Natl Labs, Intelligent Syst & Robot Ctr, POB 5800, Albuquerque, NM 87185 USA. NR 30 TC 14 Z9 14 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1042-296X J9 IEEE T ROBOTIC AUTOM JI IEEE Trans. Robot. Autom. PD FEB PY 1999 VL 15 IS 1 BP 174 EP 186 DI 10.1109/70.744612 PG 13 WC Automation & Control Systems; Engineering, Electrical & Electronic; Robotics SC Automation & Control Systems; Engineering; Robotics GA 164UJ UT WOS:000078481700016 ER PT J AU Mosher, JC Leahy, RM AF Mosher, JC Leahy, RM TI Source localization using recursively applied and projected (RAP) MUSIC SO IEEE TRANSACTIONS ON SIGNAL PROCESSING LA English DT Article DE array signal processing; EEG; MEG; MUSIC; signal subspace; source localization ID ARRAY; PERFORMANCE; LOCATION AB A new method for source localization is described that is based on a modification of the well-known MUSIC algorithm. In classical MUSIC, the array manifold vector is projected onto an estimate of the signal subspace. Errors in the estimate of the signal subspace can make localization of multiple sources difficult, Recursively applied and projected (RAP) MUSIC uses each successively located source to form an intermediate array gain matrix and projects both the array manifold and the signal subspace estimate into its orthogonal complement. The MUSIC projection to find the next source is then performed in this reduced subspace, Special assumptions about the array manifold structure, such as Vandermonde or shift invariance, are not required. Using the metric of principal angles, we describe a general form of the RAP-MUSIC algorithm for the case of diversely polarized sources. Through a uniform linear array simulation with two highly correlated sources, we demonstrate the improved Monte Carlo error performance of RAP-MUSIC relative to MUSIC and two other sequential subspace methods: S and IES-MUSIC, We then demonstrate the more general utility of this algorithm for multidimensional array manifolds in a magnetoencephalography (MEG) source localization simulation. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ So Calif, Signal & Image Proc Inst, Los Angeles, CA 90089 USA. RP Mosher, JC (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 17 TC 171 Z9 177 U1 0 U2 8 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1053-587X J9 IEEE T SIGNAL PROCES JI IEEE Trans. Signal Process. PD FEB PY 1999 VL 47 IS 2 BP 332 EP 340 DI 10.1109/78.740118 PG 9 WC Engineering, Electrical & Electronic SC Engineering GA 158PJ UT WOS:000078123700004 ER PT J AU Xu, NP Shi, ZF Fan, YQ Dong, JH Shi, J Hu, MZC AF Xu, NP Shi, ZF Fan, YQ Dong, JH Shi, J Hu, MZC TI Effects of particle size of TiO2 on photocatalytic degradation of methylene blue in aqueous suspensions SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID CARBON-DIOXIDE; OXIDATION; POWDERS; OXIDE AB The influence of particle size of TiO2 on the photocatalytic degradation of methylene blue (MB) in a suspended aqueous solution has been studied. The results suggested that the adsorption rate and adsorbability of MB on suspended TiO2 particles increased as the particle sizes of TiO2 decreased. Photocatalytic activity of TiO2 also increased as the particle size of TiO2 became smaller, especially when the particle size is less than 30 nm. The half-life (t(0.5)) of the photocatalytic degradation of MB also decreased as the particle sizes of TiO2 decreased. The first-order reaction rate constant for photodegradation of MB increased as the particle size of TiO2 decreased. The initial degradation rate of MB in a suspended model was higher than that of a fixed-bed model. This will overcome the difficulty of preparation of ultrafine TiO2 catalyst particles. Once the problem of separation of fine TiO2 particles is solved, a TiO2 suspended photoreactor could be provided on an industrial basis. C1 Nanjing Univ Chem Technol, Membrane Sci & Technol Res Ctr, Nanjing 210009, Peoples R China. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. RP Xu, NP (reprint author), Nanjing Univ Chem Technol, Membrane Sci & Technol Res Ctr, Nanjing 210009, Peoples R China. OI , Yiqun/0000-0002-2455-8979; Hu, Michael/0000-0001-8461-9684 NR 13 TC 177 Z9 186 U1 9 U2 65 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 FEB PY 1999 VL 38 IS 2 BP 373 EP 379 DI 10.1021/ie980378u PG 7 WC Engineering, Chemical SC Engineering GA 166FG UT WOS:000078565100006 ER PT J AU Husson, SM King, CJ AF Husson, SM King, CJ TI Multiple-acid equilibria in adsorption of carboxylic acids from dilute aqueous solution SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID WEAK ORGANIC ELECTROLYTES; ACTIVATED CARBON; ACETIC-ACID; EXTRACTION; SORPTION; SYSTEMS; LIQUID; PH AB Equilibria were measured for adsorption of carboxylic acids from aqueous, binary-add mixtures of lactic and succinic acids and acetic and formic acids onto basic polymeric sorbents. The experimentally determined adsorption isotherms compared well with model predictions, confirming that simple extensions from adsorption of individual acids apply. Fixed-bed studies were carried out that establish the efficacy of chromatographic fractionation of lactic and succinic acids using basic polymeric sorbents. Finally, sequential thermal and solvent; regeneration of lactic and acetic acid-laden sorbents was investigated as a method to fractionate among coadsorbed volatile and nonvolatile acids. Essentially complete removal of the acetic acid from the acid-laden sorbent was achieved by vaporization under the conditions used; a small amount of loss of lactic acid (about 11%) was observed. C1 Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP King, CJ (reprint author), Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. NR 30 TC 25 Z9 25 U1 0 U2 10 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 FEB PY 1999 VL 38 IS 2 BP 502 EP 511 DI 10.1021/ie9804430 PG 10 WC Engineering, Chemical SC Engineering GA 166FG UT WOS:000078565100021 ER PT J AU Meyer, MK Thom, AJ Akinc, M AF Meyer, MK Thom, AJ Akinc, M TI Oxide scale formation and isothermal oxidation behavior of Mo-Si-B intermetallics at 600-1000 degrees C SO INTERMETALLICS LA English DT Article ID SILICON AB Initial scale formation in the range 600-1000 degrees C and isothermal oxidation behavior at 1000 degrees C was investigated for Mo-Si-B intermetallics containing 81-88 wt% molybdenum. All compositions exhibited an initial transient oxidation period consisting of a mass gain due to MoO3 and SiO2 formation, followed by a rapid mass loss starting at 750 degrees C due to MoO3 volatilization. After the initial transient oxidation period, oxidation proceeded at a much slower rate. During isothermal oxidation at 1000 degrees C the oxidation rate was found to vary inversely with the ratio of B/Si in the intermetallic, indicating that viscous flow of the scale was an important factor in determining the isothermal oxidation rate at 1000 degrees C. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Meyer, MK (reprint author), Argonne Natl Lab W, Idaho Falls, ID 83403 USA. OI Meyer, Mitchell/0000-0002-1980-7862 NR 9 TC 111 Z9 114 U1 1 U2 8 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 FEB PY 1999 VL 7 IS 2 BP 153 EP 162 DI 10.1016/S0966-9795(98)00058-2 PG 10 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 166TF UT WOS:000078592700003 ER PT J AU Nieh, TG Hsiung, LM Wadsworth, J AF Nieh, TG Hsiung, LM Wadsworth, J TI Superplastic behavior of a powder metallurgy TiAl alloy with a metastable microstructure SO INTERMETALLICS LA English DT Article DE superplasticity; intermetallics; phase transformations; grain boundary; cavitation ID INTERMETALLIC COMPOUND; MECHANICAL-PROPERTIES; TEMPERATURE; DEFORMATION AB Superplasticity in a powder metallurgy (P/M) TiAl alloy (Ti-47Al-2Cr-1Nb-1Ta) with a metastable B2 phase coexisted with a fine-grained gamma + alpha(z) duplex structure has been studied. Alloy samples were tested at temperatures ranging from 650 to 1100 degrees C, and at strain rates ranging from 10(-6) to 10(-4) s(-1). An elongation of over 300% was obtained at a strain rate of 2x10(-5) s(-1) and at a temperature of 800 degrees C, which is close to the ductile-to-brittle transition temperature of the alloy. This is in contrast to the prior observations of superplastic behavior of TiAl alloys in which a typical temperature of 1000 degrees C is usually required for achieving superplasticity. It is suggested that the occurrence of low-temperature (800 degrees C) superplasticity in the present alloy is primarily due to the presence of a metastable B2 phase in addition to a fine-grained (alpha(2)+gamma) duplex microstructure. The metastable B2 phase continues to decompose into fine-grained alpha(2) and gamma phases, which promotes grain boundary sliding during superplastic deformation. The retained fine B2 grains accommodate the sliding strains to reduce the propensity of cavitation at grain triple junctions and thus delay the cavitation and fracture process. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Nieh, TG (reprint author), Lawrence Livermore Natl Lab, L-369,POB 808, Livermore, CA 94550 USA. RI Nieh, Tai-Gang/G-5912-2011 OI Nieh, Tai-Gang/0000-0002-2814-3746 NR 20 TC 45 Z9 49 U1 0 U2 5 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0966-9795 J9 INTERMETALLICS JI Intermetallics PD FEB PY 1999 VL 7 IS 2 BP 163 EP 170 DI 10.1016/S0966-9795(98)00017-X PG 8 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 166TF UT WOS:000078592700004 ER PT J AU Fu, CL Wang, XD Ye, YY Ho, KM AF Fu, CL Wang, XD Ye, YY Ho, KM TI Phase stability, bonding mechanism, and elastic constants of Mo5Si3 by first-principles calculation SO INTERMETALLICS LA English DT Article DE Mo5Si3; first-principles calculation; phase stability; elastic constants; thermal expansion coefficients ID ELECTRONIC-STRUCTURE; BEHAVIOR; BORON AB We present results of first-principles local-density-functional calculations of the structural and elastic properties of Mo5Si3. Among the three different structures (D8(m), D8(8), and D8(l)), the D8(m) structure (referred to as the T1 phase) has the greatest binding with a high heat of formation of -3.8 eV/formula unit. The bonding in Mo5Si3 is found to have pronounced covalent components, characterized by the planar Mo-Si-Mo triangular bonding units on the (001) plane and by the unusually short Mo-Mo bonds directly along the c-axis. The calculated six elastic constants of the D8(m) structure are in excellent agreement with the experimental values. While the bonding in the (001) basal plane is stronger than the bonding along the [001] direction (i.e. C-12 + C-12 > C-33 and C-66 > C-44), the crystal anharmonicity is found to be higher along the [001] direction. The implication of our results on the anisotropy of thermal expansion coefficients is briefly discussed. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames Lab, US Dept Energy, Ames, IA 50011 USA. RP Fu, CL (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. NR 9 TC 110 Z9 127 U1 0 U2 13 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 FEB PY 1999 VL 7 IS 2 BP 179 EP 184 DI 10.1016/S0966-9795(98)00018-1 PG 6 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 166TF UT WOS:000078592700006 ER PT J AU Yang, ZJ Hull, JR Lockwood, JA Rossing, TD AF Yang, ZJ Hull, JR Lockwood, JA Rossing, TD TI Forces and torques between two square current loops SO INTERNATIONAL JOURNAL OF APPLIED ELECTROMAGNETICS AND MECHANICS LA English DT Article DE magnetic bearing; magnetic force ID COUPLINGS AB We derive closed-form expressions for the magnetic forces and torques between two coaxial square current loops as a function of their relative tilt angle. These expressions involve simple numerical integrations. An analytic expression for the torsion constant at zero tilt angle is derived for loop filaments and for loops of finite axial extent. C1 Argonne Natl Lab, Argonne, IL 60439 USA. No Illinois Univ, Dept Phys, De Kalb, IL 60115 USA. NR 8 TC 0 Z9 0 U1 0 U2 1 PU IOS PRESS PI AMSTERDAM PA VAN DIEMENSTRAAT 94, 1013 CN AMSTERDAM, NETHERLANDS SN 1383-5416 J9 INT J APPL ELECTROM JI Int. J. Appl. Electromagn. Mech. PD FEB PY 1999 VL 10 IS 1 BP 63 EP 76 PG 14 WC Engineering, Electrical & Electronic; Mechanics; Physics, Applied SC Engineering; Mechanics; Physics GA 154TW UT WOS:000077906000005 ER PT J AU Spano, D Cesaraccio, C Duce, P Snyder, RL AF Spano, D Cesaraccio, C Duce, P Snyder, RL TI Phenological stages of natural species and their use as climate indicators SO INTERNATIONAL JOURNAL OF BIOMETEOROLOGY LA English DT Article; Proceedings Paper CT ISB Phenology Symposium CY MAR 26-27, 1998 CL BOSTON, MASSACHUSETTS DE phenology; climate change; Mediterranean species; degree-days ID TEMPERATURE AB The objectives of this paper are to: (1) present 10 years of phenological data for nine natural species growing in a Mediterranean-type climate, (2) present threshold temperatures that were derived for the computation of cumulative degree-days (CDD), and (3) evaluate the sensitivity of the nine natural species to weather variability. The study was conducted at the Phenological Research Garden of Oristano, Sardinia, Italy, during the period 1986-96. The observations were made on five typical Mediterranean species and four species that are typical of higher latitudes. The mean annual pattern of phenological events and the CDD from 1 January are given for each development stage. Temperature thresholds were evaluated by comparing the standard deviation about the mean number of days in the development period for each species. A good relationship between timing of phenophase occurrence and;temperature was observed for the Mediterranean species, which were little affected by variations in rainfall. Phenological development of the nonnative species was affected by springtime rainfall. C1 Univ Sassari, Dipartimento Econ & Sistemi Arborei, I-07100 Sassari, Italy. CNR, Ist Monitoraggio Agroecosistemi, Sassari, Italy. Univ Calif Lawrence Livermore Natl Lab, Dept Land Air & Water Resources & Agr Engn, Livermore, CA 95616 USA. RP Spano, D (reprint author), Univ Sassari, Dipartimento Econ & Sistemi Arborei, Via De Nicola, I-07100 Sassari, Italy. RI Duce, Pierpaolo/B-7634-2015; Cesaraccio, Carla/C-1515-2015 OI Duce, Pierpaolo/0000-0002-5011-2903; Cesaraccio, Carla/0000-0002-1642-4663 NR 28 TC 61 Z9 72 U1 3 U2 28 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0020-7128 J9 INT J BIOMETEOROL JI Int. J. Biometeorol. PD FEB PY 1999 VL 42 IS 3 BP 124 EP 133 DI 10.1007/s004840050095 PG 10 WC Biophysics; Environmental Sciences; Meteorology & Atmospheric Sciences; Physiology SC Biophysics; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Physiology GA 169AT UT WOS:000078725900003 ER PT J AU Knapp, FF Kropp, J AF Knapp, FF Kropp, J TI BMIPP-design and development SO INTERNATIONAL JOURNAL OF CARDIAC IMAGING LA English DT Article DE BMIPP; methyl-branched fatty acids; myocardial imaging; radioiodinated fatty acids ID SUBACUTE MYOCARDIAL-INFARCTION; BRANCHED FATTY-ACIDS; RAT HEARTS; 15-(P-IODOPHENYL)-3,3-DIMETHYLPENTADECANOIC ACID; TELLURIUM POSITION; LIPID DISTRIBUTION; CANINE MYOCARDIUM; HYPERTENSIVE RATS; FREE-UNIVERSITY; IMAGING AGENTS AB In the early 1980s a major obstacle for myocardial SPECT using iodine-123-labeled fatty acids and imaging technology available at that time was the rapid metabolism and myocardial washout of activity. Development of the 15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) fatty acid analogue was based on the established effects of methyl-branching in delineating the enzymatic aberration in Refum's disease and our early studies with the tellurium (Te)-substituted fatty acid analogues. Extensive animal studies with the Te-fatty acids demonstrated that this major structural alteration did not affect initial myocardial extraction, but could successfully inhibit subsequent metabolism and significantly delay washout. Tracer kinetic evaluation and metabolic studies on experimental animals and Langendorff-perfused rat hearts clearly demonstrated that introduction of methyl-branching is an effective approach which alters tracer kinetics by delaying myocardial washout of radioiodinated fatty acids by increasing myocardial retention. Although irreversible retention of iodine-123 BMIPP is not observed, subsequent extensive human studies have clearly substantiated the delayed myocardial washout of BMIPP in comparison with the p-IPPA straight chain analogue. Although contemporary SPECT capabilities allow much more rapid acquisition periods, the delayed washout is still a practical benefit in relation to the use of BMIPP. Most important, the unexpected mis-match which has been widely observed between perfusion tracer distribution and the regional BMIPP distribution (i.e. BMIPP < flow tracer) has been linked to the identification of jeopardized, but viable myocardial regions. In this paper the development of BMIPP is discussed and the results of recent studies focusing on evaluating the effects of the absolute configuration of the branched methyl group using the 3(R)-BMIPP and 3(S)-BMIPP are described. C1 Oak Ridge Natl Lab, Nucl Med Grp, Oak Ridge, TN 37831 USA. Carl Gustav Carus Univ, Dept Nucl Med, Dresden, Germany. RP Knapp, FF (reprint author), Oak Ridge Natl Lab, Nucl Med Grp, Bldg 4501,Mail Stop 6229, Oak Ridge, TN 37831 USA. NR 61 TC 15 Z9 15 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-9899 J9 INT J CARDIAC IMAG JI Int. J. Card. Imaging PD FEB PY 1999 VL 15 IS 1 BP 1 EP 9 DI 10.1023/A:1006147228352 PG 9 WC Cardiac & Cardiovascular Systems; Radiology, Nuclear Medicine & Medical Imaging SC Cardiovascular System & Cardiology; Radiology, Nuclear Medicine & Medical Imaging GA 222QJ UT WOS:000081796000002 PM 10453397 ER PT J AU Hart, WE Goldbaum, M Cote, B Kube, P Nelson, MR AF Hart, WE Goldbaum, M Cote, B Kube, P Nelson, MR TI Measurement and classification of retinal vascular tortuosity SO INTERNATIONAL JOURNAL OF MEDICAL INFORMATICS LA English DT Article; Proceedings Paper CT 9th World Congress on Medical Informatics: Global Health Networking - A Vision for the Next Millennium (MEDINFO 98) CY 1998 CL SEOUL, SOUTH KOREA SP Int Med Informat Assoc DE tortuosity; retina; blood vessel; automated measurement ID RETINOPATHY AB Automatic measurement of blood vessel tortuosity is a useful capability for automatic ophthalmological diagnostic tools. We describe a suite of automated tortuosity measures for blood vessel segments extracted from RGB retinal images. The tortuosity measures were evaluated in two classification tasks: (1) classifying the tortuosity of blood vessel segments and (2) classifying the tortuosity of blood vessel networks. These tortuosity measures were able to achieve a classification rate of 91% for the first problem and 95% on the second problem, which confirms that they capture much of the ophthalmologists' notion of tortuosity. Finally, we discuss how the accuracy of these measures can be influence by the method used to extract the blood vessel segments. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved. C1 Sandia Natl Labs, Dept Appl & Numer Math, Albuquerque, NM 87185 USA. Univ Calif San Diego, Dept Ophthalmol, San Diego, CA 92103 USA. Registry Inc, San Diego, CA USA. Univ Calif San Diego, Dept Comp Sci & Engn, San Diego, CA 92103 USA. Data Vector, San Diego, CA USA. RP Hart, WE (reprint author), Sandia Natl Labs, Dept Appl & Numer Math, POB 5800, Albuquerque, NM 87185 USA. EM wehart@cs.sandia.gov FU NLM NIH HHS [R01LM05759] NR 19 TC 122 Z9 125 U1 0 U2 10 PU ELSEVIER SCI IRELAND LTD PI CLARE PA CUSTOMER RELATIONS MANAGER, BAY 15, SHANNON INDUSTRIAL ESTATE CO, CLARE, IRELAND SN 1386-5056 J9 INT J MED INFORM JI Int. J. Med. Inform. PD FEB-MAR PY 1999 VL 53 IS 2-3 BP 239 EP 252 DI 10.1016/S1386-5056(98)00163-4 PG 14 WC Computer Science, Information Systems; Health Care Sciences & Services; Medical Informatics SC Computer Science; Health Care Sciences & Services; Medical Informatics GA 173ZV UT WOS:000079010400014 PM 10193892 ER PT J AU Johnson, KL Brenner, DJ Nath, J Tucker, JD Geard, CR AF Johnson, KL Brenner, DJ Nath, J Tucker, JD Geard, CR TI Radiation-induced breakpoint misrejoining in human chromosomes: random or non-random? SO INTERNATIONAL JOURNAL OF RADIATION BIOLOGY LA English DT Review ID IN-SITU HYBRIDIZATION; HUMAN-LYMPHOCYTES; X-IRRADIATION; STRUCTURAL-ABERRATIONS; BIOLOGICAL DOSIMETRY; IONIZING-RADIATION; BREAKS; FISH; TRANSLOCATIONS; REARRANGEMENTS AB Purpose: To investigate whether radiation-induced misrejoining of chromosome breakpoints is randomly or non-randomly distributed throughout the human genome. Materials and methods: Data were combined from as many published cytogenetic studies as possible. The percentage of radiation-induced breaks per megabase (Mb) of DNA between all human chromosomes was calculated, and the observed and expected numbers of breakpoints based on DNA content between and within chromosomes were compared. Results: A DNA-proportional distribution of breakpoints in 14 autosomes and a statistically significant deviation from proportionality in the other eight autosomes and the sex chromosomes was found. Regression analysis showed no significant change in breakpoint frequency per Mb of DNA relative to autosome size. Analysis between chromosome arms showed a non-random distribution of induced breakpoints within certain autosomes, particularly the acrocentrics. In cases of non-random distributions, a prevalence of events was found at heterochromatic regions and/or telomeres, and a clustering of breakpoints was found near the centromeres of many chromosomes. Conclusions: There is an approximately linear proportionality between autosomal DNA content and observed breakpoint number, suggesting that subsets of autosomes can be used to estimate accurately the overall genomic frequency of misrejoined breakpoints contingent upon a carefully selected subset. However, this conclusion may not apply to the sex chromosomes. The results also support the influence of chromatin organization and/or preferential DNA repair/misrejoining on the distribution of induced breakpoints. However, these effects are not sufficient at a global level to dismiss the value of cytogenetic analysis using a genome subset for biodosimetry. C1 Columbia Univ, Ctr Radiol Res, New York, NY 10032 USA. W Virginia Univ, Genet & Dev Biol Program, Morgantown, WV 26506 USA. Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94551 USA. RP Johnson, KL (reprint author), Columbia Univ, Ctr Radiol Res, 630 W 168th St,VC11-230, New York, NY 10032 USA. EM kj77@columbia.edu FU NCI NIH HHS [CA-49062]; NCRR NIH HHS [P41 RR-11623]; NIEHS NIH HHS [ES 07361] NR 48 TC 46 Z9 50 U1 0 U2 0 PU INFORMA HEALTHCARE PI LONDON PA TELEPHONE HOUSE, 69-77 PAUL STREET, LONDON EC2A 4LQ, ENGLAND SN 0955-3002 J9 INT J RADIAT BIOL JI Int. J. Radiat. Biol. PD FEB PY 1999 VL 75 IS 2 BP 131 EP 141 DI 10.1080/095530099140582 PG 11 WC Biology; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 167JC UT WOS:000078627900001 PM 10072174 ER PT J AU Zavaliy, IY Pecharsky, VK Miller, GJ Akselrud, LG AF Zavaliy, IY Pecharsky, VK Miller, GJ Akselrud, LG TI Hydrogenation of Zr6MeX2 intermetallic compounds (Me=Fe, Co, Ni; X=Al, Ga, Sn): Crystallographic and theoretical analysis SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article DE intermetallic compounds; band structure; X-ray crystallography; hydrogen storage ID CRYSTAL-STRUCTURE; DIFFRACTION AB Experimental studies on the series of ternary intermetallic compounds, Zr6MeX2, where Me=Fe, Co, and Ni, and X=Al, Ga, and Sn, show that they have large hydrogen storage capacities ranging from 9.3 to 10.8 H-atoms per formula unit. The crystal structure of the parent intermetallic compounds changes upon hydrogenation with a two-fold increase of the crystallographic c-axis length and a corresponding change in space group from P (6) over bar m2 to P (6) over bar 2c. pull profile (Rietveld) refinement using X-ray powder diffraction data indicates that the crystal structures of the new hydrides, Zr6CoAl2H10, Zr6NiAl2H9.7 and Zr(6)NiSn(2)H(10.)8 are analogous to Zr6FeAl2D10, which was examined by neutron powder diffraction. Thermal desorption of hydrogen in all hydrides occurs in the temperature range between 400 and 900 K and is characterized by two similar events. The compounds Zr6FeAl2Hx (x=0, 10 and 0.1-0.2) order magnetically at 45, 155 and 10 K, respectively. Electronic structure calculations are carried out on Zr6FeAl2Hx (0 less than or equal to x less than or equal to 10) to interpret their structural and thermal behavior. Site energies for hydrogen incorporation, energetics of hydrogen desorption, as well as quantitative details of the densities of states are evaluated. Site energies and metal-metal bonding largely affect the maximum hydrogen content, while H-H repulsions constitute the greatest driving force for the change in space group upon hydrogenation. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Iowa State Univ Sci & Technol, Dept Chem, Ames, IA 50011 USA. Natl Acad Sci Ukraine, Phys & Mech Inst, UA-290601 Lviv, Ukraine. Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Mat Sci & Engn, Ames, IA 50011 USA. Lviv State Univ, Dept Inorgan Chem, UA-290602 Lviv, Ukraine. RP Miller, GJ (reprint author), Iowa State Univ Sci & Technol, Dept Chem, Ames, IA 50011 USA. NR 31 TC 4 Z9 5 U1 2 U2 6 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD FEB 1 PY 1999 VL 283 IS 1-2 BP 106 EP 116 DI 10.1016/S0925-8388(98)00877-9 PG 11 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 164ZM UT WOS:000078493500021 ER PT J AU McCusker, LB Von Dreele, RB Cox, DE Louer, D Scardi, P AF McCusker, LB Von Dreele, RB Cox, DE Louer, D Scardi, P TI Rietveld refinement guidelines SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article ID POWDER DIFFRACTION DATA; UNION-OF-CRYSTALLOGRAPHY; X-RAY; PREFERRED ORIENTATION; ROUND-ROBIN; DIFFRACTOMETRY; COMMISSION; PATTERN AB A set of general guidelines for structure refinement using the Rietveld (whole-profile) method has been formulated by the International Union of Crystallography Commission on Powder Diffraction. The practical rather than the theoretical aspects of each step in a typical Rietveld refinement are discussed with a view to guiding newcomers in the field. The focus is on X-ray powder diffraction data collected on a laboratory instrument, but features specific to data from neutron (both constant-wavelength and time-of-flight) and synchrotron radiation sources are also addressed. The topics covered include (i) data collection, (ii) background contribution, (iii) peak-shape function, (iv) refinement of profile parameters, (v) Fourier analysis with powder diffraction data, (vi) refinement of structural parameters, (vii) use of geometric restraints, (viii) calculation of e.s.d.'s, (ix) interpretation of R values and (x) some common problems and possible solutions. C1 ETH Zurich, Lab Kristallog, Zurich, Switzerland. Univ Calif Los Alamos Natl Lab, LANSCE, Los Alamos, NM USA. Brookhaven Natl Lab, Dept Phys, Brookhaven, NY USA. Univ Rennes 1, Chim Solide & Inorgan Mol Lab, CNRS, UMR 6511, F-35042 Rennes, France. Univ Trent, Dipartimento Ingn Mat, I-38050 Mesiano, TN, Italy. RP McCusker, LB (reprint author), ETH Zurich, Lab Kristallog, Zurich, Switzerland. EM lynne.mccusker@kristall.erdw.ethz.ch RI Scardi, Paolo/E-2085-2014; OI McCusker, Lynne/0000-0003-0074-1733 NR 44 TC 852 Z9 868 U1 19 U2 249 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 FEB 1 PY 1999 VL 32 BP 36 EP 50 DI 10.1107/S0021889898009856 PN 1 PG 15 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 173NK UT WOS:000078986500006 ER PT J AU Weller, A Frangos, W Seichter, M AF Weller, A Frangos, W Seichter, M TI Three-dimensional inversion of induced polarization data from simulated waste SO JOURNAL OF APPLIED GEOPHYSICS LA English DT Article DE electrical resistivity; geoelectrical prospection; induced polarization; inversion algorithm ID SPECTRAL-INDUCED POLARIZATION AB The Idaho National Laboratory (INEL) Cold Test Pit (CTP) has been carefully constructed to simulate buried hazardous waste sites. An induced polarization (IP) survey of the CTP shows a very strong polarization and a modest resistivity response associated with the simulated waste. A three-dimensional (3-D) inversion algorithm based on the simultaneous iterative reconstruction technique (SIRT) and finite difference forward modelling has been applied to generate a subsurface model of complex resistivity. The lateral extents of the waste zone are well resolved. Limited depth extent is recognized, but the bottom of the waste appears too deep. With a modelling experiment, the intrinsic polarizability of the waste material is determined. Since IP is a technique for detection of diffuse occurrences of metallic material, this method holds promise as a method to distinguish buried waste from conductive soil material. (C) 1949 Elsevier Science B.V. All rights reserved. C1 Tech Univ Clausthal, Inst Geophys, D-38678 Clausthal Zellerfeld, Germany. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. Tech Univ Braunschweig, Inst Geophys & Meteorol, D-38106 Braunschweig, Germany. RP Weller, A (reprint author), Tech Univ Clausthal, Inst Geophys, Arnold Sommerfeld Str 1, D-38678 Clausthal Zellerfeld, Germany. EM andreas.weller@tu-clausthal.de NR 28 TC 11 Z9 12 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0926-9851 J9 J APPL GEOPHYS JI J. Appl. Geophys. PD FEB PY 1999 VL 41 IS 1 BP 31 EP 47 DI 10.1016/S0926-9851(98)00036-6 PG 17 WC Geosciences, Multidisciplinary; Mining & Mineral Processing SC Geology; Mining & Mineral Processing GA 170LX UT WOS:000078808100003 ER PT J AU Song, J Gao, W AF Song, J Gao, W TI An improved method to derive surface albedo from narrowband AVHRR satellite data: Narrowband to broadband conversion SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID BAND; REFLECTANCE; RADIATION; CHANNELS AB A method was investigated to estimate broadband surface shortwave albedo from the narrowband reflectances obtained by the Advanced Very High Resolution Radiometers (AVHRRs) on board the polar orbiting satellites. Field experiments were conducted to measure simultaneously multispectral narrowband reflectances and broadband albedo over various vegetation and soil surfaces. These data were combined to examine the behavior of narrowband-to-broadband (NTB) conversion factors for different surfaces. Many previous studies have used constant NTB conversion factors for the AVHRR data. The results from this investigation indicate that the optimal NTB conversion factors for AVHRR channels 1 and 2 have a strong dependence on the amount of green vegetation within the field of view. Two conversion factors, f(1) and f(2), were established to quantify, respectively, 1) the relationship between the reflectance in the narrow red wave band and the total reflectance within the whole visible subregion (0.3-0.685 mu(m)) and 2) the relationship between the reflectance in the narrow near-infrared wave band and the total reflectance within the whole near infrared subregion (0.685-2.8 mu m). Values of f(1) and f(2), calculated from field data, correlated well with the normalized difference vegetation index (NDVI), largely because of the unique characteristics of light absorption and scattering within the red and near-infrared wave bands by green leaves. The f(1)-NDVI and f(2)-NDVI relationships developed from this study were used to infer empirical coefficients needed to estimate Sui face albedo from AVHRR data. The surface albedo values calculated by the new method agreed with ground-based measurements within a root mean-square error of 0.02, which is better than other methods that use constant empirical coefficients. Testing with albedo measurements made by unmanned aerospace vehicles during a field campaign also indicates that the new method provides an improved estimate of surface albedo. C1 No Illinois Univ, Dept Geog, De Kalb, IL 60115 USA. Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. RP Song, J (reprint author), No Illinois Univ, Dept Geog, De Kalb, IL 60115 USA. NR 16 TC 28 Z9 34 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD FEB PY 1999 VL 38 IS 2 BP 239 EP 249 DI 10.1175/1520-0450(1999)038<0239:AIMTDS>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 166AH UT WOS:000078553700007 ER PT J AU Knapp, JA Follstaedt, DM Myers, SM Barbour, JC Friedmann, TA AF Knapp, JA Follstaedt, DM Myers, SM Barbour, JC Friedmann, TA TI Finite-element modeling of nanoindentation SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID PULSED-LASER DEPOSITION; MECHANICAL-PROPERTIES; ELASTIC-MODULUS; THIN-FILMS; ALLOYS; INDENTATION; HARDNESS; LAYERS AB Procedures have been developed based on finite-element modeling of nanoindentation data to obtain the mechanical properties of thin films and ion-beam-modified layers independently of the properties of the underlying substrates. These procedures accurately deduce the yield strength, Young's elastic modulus, and layer hardness from indentations as deep as 50% of the layer thickness or more. We have used these procedures to evaluate materials ranging from ion implanted metals to deposited, diamond-like carbon layers. The technique increases the applicability of indentation testing to very thin layers, composite layers, and modulated compositions. This article presents an overview of the procedures involved and illustrates them with selected examples. (C) 1999 American Institute of Physics. [S0021-8979(99)04603-4]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Knapp, JA (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. EM jaknapp@sandia.gov NR 36 TC 162 Z9 163 U1 1 U2 23 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD FEB 1 PY 1999 VL 85 IS 3 BP 1460 EP 1474 DI 10.1063/1.369178 PG 15 WC Physics, Applied SC Physics GA 158VB UT WOS:000078137100025 ER PT J AU Takamoto, T Yumaguchi, M Ikeda, E Agui, T Kurita, H Al-Jassim, M AF Takamoto, T Yumaguchi, M Ikeda, E Agui, T Kurita, H Al-Jassim, M TI Mechanism of Zn and Si diffusion from a highly doped tunnel junction for InGaP/GaAs tandem solar cells SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID GALLIUM-ARSENIDE; EFFICIENCY; 30-PERCENT; ZINC AB Diffusion of impurities (Zn and Si) from a tunnel junction during epitaxial growth and the effects of impurity diffusion on InGaP/GaAs tandem cell properties have been investigated. Zn diffusion from the tunnel junction has been found to deteriorate the effect of the back-surface field layer on minority carrier reflectance in the InGaP top cell and degrade the quantum efficiency of the top cell. Furthermore, Zn diffusion has been found to be enhanced around the threading dislocations from a GaAs substrate and creates shunt paths only in the top cell region. Si diffusion, which degrades the quantum efficiency of the GaAs bottom cell, has also been observed when a different substrate with high etch pit density was used. Such anomalous diffusion of Zn has been found to be suppressed by using a double-hetero structure InGaP tunnel junction sandwiched by AlInP layers. It has been found that the Zn diffusion occurs as a layer highly doped with Si being formed nearby and Zn diffuses in the opposite direction from the Si-doped layer. The Zn diffusion is thought to be caused by group III self-diffusion which originates in the highly doped n-type layer. The direction of Zn diffusion is thought to be due to Coulombic repulsion between the substitutional Zn on the Ga site and the substitutional Si on the As site. The large energies of the formation and migration of group III vacancies in the AlInP barrier layers and InGaP tunnel junction layers are thought to suppress Zn diffusion from the tunnel junction. (C) 1999 American Institute of Physics. [S0021-8979(99)04203-6]. C1 Toyota Technol Inst, Tempa Ku, Nagoya, Aichi 4688511, Japan. Japan Energy Corp, Cent Res Lab, Toda, Saitama 335, Japan. Natl Renewable Energy Lab, Golden, CO USA. RP Takamoto, T (reprint author), Toyota Technol Inst, Tempa Ku, 2-12-1 Hisakata, Nagoya, Aichi 4688511, Japan. EM masafumi@toyota-ti.ac.jp RI 马, 忠权/I-4498-2014 OI 马, 忠权/0000-0002-6471-2985 NR 14 TC 48 Z9 49 U1 0 U2 22 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD FEB 1 PY 1999 VL 85 IS 3 BP 1481 EP 1486 DI 10.1063/1.369278 PG 6 WC Physics, Applied SC Physics GA 158VB UT WOS:000078137100027 ER PT J AU Lippert, T Webb, RL Langford, SC Dickinson, JT AF Lippert, T Webb, RL Langford, SC Dickinson, JT TI Dopant induced ablation of poly(methyl methacrylate) at 308 nm SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ULTRAVIOLET-LASER ABLATION; EXCIMER-LASER; 248 NM; POLYMER ABLATION; ROTATIONAL RELAXATION; ORGANIC POLYMERS; SOLID-STATE; POLYMETHYLMETHACRYLATE; PHOTOABLATION; FILMS AB Poly(methyl methacrylate) (PMMA) is highly resistant to laser ablation at 308 nm. Either very high fluences or absorbing dopants must be used to ablate PMMA efficiently at this wavelength. We investigate two dopants, pyrene and a common solvent, chlorobenzene, using time-of-flight mass spectroscopy. Both compounds improve the ablation characteristics of PMMA. For both dopants, the first step in ablation is an incubation process, in which absorption at 308 nm increases due to the production of C=C bonds along the polymer backbone. Incubation at 308 nm is similar to that observed for shorter ultraviolet wavelengths in previous studies. The principal ablation products and their corresponding temperatures are consistent with a photothermal ablation mechanism. (C) 1999 American Institute of Physics. [S0021-8979(99)04703-9]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Pacific Union Coll, Dept Phys, Angwin, CA 94508 USA. Washington State Univ, Dept Phys, Pullman, WA 99164 USA. RP Lippert, T (reprint author), Univ Calif Los Alamos Natl Lab, CST-6,MS J 585, Los Alamos, NM 87545 USA. RI Lippert, Thomas/N-2423-2016 NR 67 TC 49 Z9 49 U1 0 U2 4 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD FEB 1 PY 1999 VL 85 IS 3 BP 1838 EP 1847 DI 10.1063/1.369331 PG 10 WC Physics, Applied SC Physics GA 158VB UT WOS:000078137100085 ER PT J AU Butler, MA Hill, MK Spates, JJ Martin, SJ AF Butler, MA Hill, MK Spates, JJ Martin, SJ TI Pressure sensing with a flexural plate wave resonator SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB A silicon nitride membrane supported on a silicon substrate and having a sealed air cavity underneath has been used as a pressure sensor. Membrane resonances are excited and detected using conductor lines patterned on the membrane in combination with an applied magnetic field. The resonant frequency depends strongly upon membrane tension and thus the differential pressure across the membrane. (C) 1999 American Institute of Physics. [S0021-8979(99)08203-1]. C1 Sandia Natl Labs, Microsensor Res & Dev Dept, Albuquerque, NM 87185 USA. RP Butler, MA (reprint author), Sandia Natl Labs, Microsensor Res & Dev Dept, POB 5800, Albuquerque, NM 87185 USA. NR 5 TC 4 Z9 4 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD FEB 1 PY 1999 VL 85 IS 3 BP 1998 EP 2000 DI 10.1063/1.369196 PG 3 WC Physics, Applied SC Physics GA 158VB UT WOS:000078137100113 ER PT J AU Sandler, SJ Hugenholtz, P Schleper, C DeLong, EF Pace, NR Clark, AJ AF Sandler, SJ Hugenholtz, P Schleper, C DeLong, EF Pace, NR Clark, AJ TI Diversity of radA genes from cultured and uncultured Archaea: Comparative analysis of putative RadA proteins and their use as a phylogenetic marker SO JOURNAL OF BACTERIOLOGY LA English DT Article ID COMPLETE GENOME SEQUENCE; RECA PROTEIN; SACCHAROMYCES-CEREVISIAE; ARCHAEOGLOBUS-FULGIDUS; ESCHERICHIA-COLI; RECOMBINATION; YEAST; HOMOLOG; DMC1 AB Archaea-specific radA primers were used with PCR to amplify fragments of radA genes from 11 cultivated archaeal species and one marine sponge tissue sample that contained essentially an archaeal monoculture, The amino acid sequences encoded by the PCR fragments, three RadA protein sequences previously published (21), and two new complete RadA sequences were aligned with representative bacterial RecA proteins and eucaryal Rad51 and Dmc1 proteins. The alignment supported the existence of four insertions and one deletion in the archaeal and eucaryal sequences relative to the bacterial sequences. The sizes of three of the insertions were found to have taxonomic and phylogenetic significance. Comparative analysis of the RadA sequences, omitting amino acids in the insertions and deletions, shows a cladal distribution of species which mimics to a large extent that obtained by a similar analysis of archaeal 16S rRNA sequences. The PCR technique also was used to amplify fragments of 15 radA genes from uncultured natural sources. Phylogenetic analysis of the amino acid sequences encoded by these fragments reveals several clades with affinity, sometimes only distant, to the putative RadA proteins of several species of Crenarcheota. The two most deeply branching archaeal radA genes found had some amino acid deletion and insertion patterns characteristic of bacterial recA genes. Possible explanations are discussed. Finally, signature codons are presented to distinguish among RecA protein family members. C1 Univ Calif Berkeley, Dept Mol & Cell Biol, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Plant & Microbial Biol, Berkeley, CA 94720 USA. Univ Calif Santa Barbara, Inst Marine Sci, Santa Barbara, CA 93106 USA. RP Clark, AJ (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, 1 Cyclotron Rd,Bldg 74-157, Berkeley, CA 94720 USA. RI Hugenholtz, Philip/G-9608-2011 FU NIAID NIH HHS [AI05371] NR 30 TC 40 Z9 47 U1 0 U2 1 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 USA SN 0021-9193 J9 J BACTERIOL JI J. Bacteriol. PD FEB PY 1999 VL 181 IS 3 BP 907 EP 915 PG 9 WC Microbiology SC Microbiology GA 163EQ UT WOS:000078390600027 PM 9922255 ER PT J AU Roy, ME Rho, JY Tsui, TY Evans, ND Pharr, GM AF Roy, ME Rho, JY Tsui, TY Evans, ND Pharr, GM TI Mechanical and morphological variation of the human lumbar vertebral cortical and trabecular bone SO JOURNAL OF BIOMEDICAL MATERIALS RESEARCH LA English DT Article DE nanoindentation; elastic modulus; hardness; vertebral cortical shell; trabecular bone ID FINITE-ELEMENT ANALYSIS; INTERVERTEBRAL-DISK; CANCELLOUS BONE; YOUNG MODULUS; COMPACT-BONE; STRENGTH; BODY; NANOINDENTATION; FRACTURE; HARDNESS AB The nanoindentation technique was used to characterize the variation in the elastic modulus and hardness of human lumbar vertebral cortical and trabecular bone. The elastic modulus (and in most cases, the hardness as well) of axially aligned trabeculae cut in the transverse direction was significantly greater than in other orientations of vertebral cortical and trabecular bone. In all cases, the elastic modulus and hardness of bone in the load-bearing direction was greater than in corresponding bone types cut in the other directions. Scanning electron micrographs of cortical shell revealed the Haversian-like canal systems expected in secondary cortical bone, but it was difficult to differentiate by morphology cortical from trabecular bone in the human lumbar vertebrae. (C) 1999 John Wiley & Sons, Inc. C1 Memphis State Univ, Dept Biomed Engn, Memphis, TN 38152 USA. Rice Univ, Dept Mat Sci, Houston, TX 77005 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Rho, JY (reprint author), Memphis State Univ, Dept Biomed Engn, Memphis, TN 38152 USA. RI Evans, Neal/F-5955-2011 NR 28 TC 91 Z9 94 U1 0 U2 10 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0021-9304 J9 J BIOMED MATER RES JI J. Biomed. Mater. Res. PD FEB PY 1999 VL 44 IS 2 BP 191 EP 197 DI 10.1002/(SICI)1097-4636(199902)44:2<191::AID-JBM9>3.0.CO;2-G PG 7 WC Engineering, Biomedical; Materials Science, Biomaterials SC Engineering; Materials Science GA 144RN UT WOS:000077329000009 PM 10397920 ER PT J AU Lane, NE Haupt, D Kimmel, DB Modin, G Kinney, JH AF Lane, NE Haupt, D Kimmel, DB Modin, G Kinney, JH TI Early estrogen replacement therapy reverses the rapid loss of trabecular bone volume and prevents further deterioration of connectivity in the rat SO JOURNAL OF BONE AND MINERAL RESEARCH LA English DT Article ID OVARIECTOMIZED RATS; PARATHYROID-HORMONE; SKELETAL RESPONSE; TURNOVER; OSTEOPOROSIS; ALENDRONATE; RESORPTION; MARKERS; WOMEN; MASS AB To evaluate the ability of estrogen replacement therapy (ERT) to prevent changes in trabecular bone volume (BV/TV) and connectivity beginning either at ovariectomy (OVX) or 5-13 days after OVX in adult female rats, the right proximal tibial was examined by three-dimensional X-ray tomographic microscopy (XTM) in vivo, Animals had XTM scans of the right tibia and then were randomized into six:groups (n = 9), Groups 2-6 had bilateral (OVX), while group 1 was sham-ovariectomized (OVXd) on day 0, Animals were treated with vehicle (groups 1 and 2) or 17 beta-estradiol therapy (ERT) at 10 mu g/kg three times per meek starting at days 0, 5, 8, and 13 post-OVX (groups 3, 4, 5, and 6), until day 50 when they were rescanned by XTM and sacrificed. Trabecular bone structural variables were calculated from XTM data (BV/TVx and beta 1/BV/TVx) and standard histomorphometry, Trabecular bone volume (BV/TVx) and the trabecular connections per cubic millimeter of trabecular bone (beta 1/BV/TVx) were maintained in both sham-OVXd animals and OVX animals given ERT from the time of OVX, However, OVX + vehicle-treated animals lost 54% BV/TVx and 46% beta 1/BV/TVx (p < 0.01 from day 0), BV/TVx and beta 1/BV/TVx decreased rapidly post-OVX to -22% and -25% at day 13 (p < 0.01 from day 0), ERT initiated at day 5, 8, and 13 post-OVX restored BV/TVx to baseline values at day 50 by modestly increasing trabecular plate thickness; hoc-ever, beta 1/BV/TVx was reduced in all OVX groups when compared with their baseline values. ERT also caused a significant reduction in bone turnover compared with OVX + vehicle; however, resorption was suppressed more than formation. These results demonstrate that ERT can restore the lost trabecular bone, but not trabecular connectivity, that occurs soon after OVX by allowing bone formation to continue in previously activated bone remodeling units while suppressing the production of new remodeling units. This may be the mechanism by which prompt intervention with estrogen and other antiresorptive agents can restore bone mass that has been lost from the increase in remodeling space, and thereby reduce the risk of osteoporotic fractures in postmenopausal women. C1 Univ Calif San Francisco, Dept Med, Div Rheumatol, San Francisco, CA 94143 USA. Univ Calif Lawrence Livermore Natl Lab, Dept Chem & Mat Sci, Livermore, CA 94550 USA. Creighton Univ, Sch Med, Osteoporosis Res Ctr, Dept Med, Omaha, NE USA. RP Lane, NE (reprint author), Univ Calif San Francisco, Dept Med, Div Rheumatol, Box 0868, San Francisco, CA 94143 USA. FU NIAMS NIH HHS [1-R01-AR 43052] NR 49 TC 71 Z9 73 U1 0 U2 1 PU BLACKWELL SCIENCE INC PI MALDEN PA 350 MAIN ST, MALDEN, MA 02148 USA SN 0884-0431 J9 J BONE MINER RES JI J. Bone Miner. Res. PD FEB PY 1999 VL 14 IS 2 BP 206 EP 214 DI 10.1359/jbmr.1999.14.2.206 PG 9 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA 161NE UT WOS:000078294700007 PM 9933474 ER PT J AU Rabinovich, D Scott, BL Nielsen, JB Abney, KD AF Rabinovich, D Scott, BL Nielsen, JB Abney, KD TI Molecular structure of ThBr4(DME)(2) (DME=1,2-dimethoxyethane) SO JOURNAL OF CHEMICAL CRYSTALLOGRAPHY LA English DT Article DE thorium; dimethoxyethane; crystal structure ID CRYSTAL-STRUCTURES; COMPLEXES; THORIUM(IV); URANIUM(IV); CHEMISTRY AB The molecular structure of ThBr4(DME)(2) (DME = 1,2-dimethoxyethane), the first structurally characterized thorium complex containing a simple bidentate ether ligand, is described. The eight-coordinate complex presents a distorted dodecahedral geometry, with Th-Br and Th-O bond lengths in the ranges 2.8516(13)-2.8712(13) Angstrom and 2.564(8)-2.620(8) Angstrom, respectively. ThBr4(DME)(2) is monoclinic, space group P2(1)/n, a = 7.672(1), b = 14.581(1), c = 15.847(2) Angstrom, beta = 102.24(1)degrees, V = 1732.4(3) Angstrom(3), and Z = 4. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Rabinovich, D (reprint author), Univ N Carolina, Dept Chem, Charlotte, NC 28223 USA. RI G, Neela/H-3016-2014; Scott, Brian/D-8995-2017 OI Scott, Brian/0000-0003-0468-5396 NR 22 TC 6 Z9 6 U1 0 U2 3 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1074-1542 J9 J CHEM CRYSTALLOGR JI J. Chem. Crystallogr. PD FEB PY 1999 VL 29 IS 2 BP 243 EP 246 DI 10.1023/A:1009542715804 PG 4 WC Crystallography; Spectroscopy SC Crystallography; Spectroscopy GA 218DR UT WOS:000081538400019 ER PT J AU Gapinski, J Steffen, W Patkowski, A Sokolov, AP Kisliuk, A Buchenau, H Russina, M Mezei, F Schober, H AF Gapinski, J Steffen, W Patkowski, A Sokolov, AP Kisliuk, A Buchenau, H Russina, M Mezei, F Schober, H TI Spectrum of fast dynamics in glass forming liquids: Does the "knee'' exist? SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DEPOLARIZED-LIGHT-SCATTERING; RELAXATION PROCESSES; NEUTRON-SCATTERING; BETA-RELAXATION; TRANSITION; SPECTROSCOPY; MODEL AB A knee-shaped feature observed earlier in light scattering spectra of Ca(0.4)K(0.3)(NO(3))(1.4) (CKN) below T(c) is used as a strong argument in favor of mode- coupling theory of the glass transition (MCT). Our careful measurements reveal no "knee" in the spectra of two glass forming liquids, CKN and ortho- terphenyl. Instead of the knee the spectra show nontrivial broadening and an increase of the intensity with a temperature increase. Both variations are confirmed by neutron scattering measurements on CKN and are neither expected in the asymptotic MCT predictions nor in any other model. (C) 1999 American Institute of Physics. [S0021-9606(99)51605-X]. C1 Max Planck Inst Polymer Res, D-55128 Mainz, Germany. Forschungszentrum Julich, Inst Festkorperforsch, D-52425 Julich, Germany. Free Univ Berlin, Inst Phys Expt, D-14195 Berlin, Germany. Hahn Meitner Inst Berlin GmbH, D-14109 Berlin, Germany. ILL, F-38190 Grenoble, France. Adam Mickiewicz Univ Poznan, Inst Phys, Poznan, Poland. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Gapinski, J (reprint author), Max Planck Inst Polymer Res, D-55128 Mainz, Germany. RI Steffen, Werner/A-1417-2009; OI Steffen, Werner/0000-0001-6540-0660; Russina, Margarita/0000-0003-2067-606X NR 17 TC 65 Z9 65 U1 3 U2 6 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 FEB 1 PY 1999 VL 110 IS 5 BP 2312 EP 2315 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 161ET UT WOS:000078276500002 ER PT J AU Challacombe, M AF Challacombe, M TI A simplified density matrix minimization for linear scaling self-consistent field theory SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ELECTRONIC-STRUCTURE CALCULATIONS; DIFFERENCE-PSEUDOPOTENTIAL METHOD; QUANTUM MOLECULAR-DYNAMICS; CONJUGATE-GRADIENT METHOD; FAST MULTIPOLE METHOD; FUNCTIONAL-THEORY; TIGHT-BINDING; SYSTEM-SIZE; NONORTHOGONAL BASIS; FOCK MATRIX AB A simplified version of the Li, Nunes and Vanderbilt [Phys. Rev. B 47, 10891 (1993)] and Daw [Phys. Rev. B 47, 10895 (1993)] density matrix minimization is introduced that requires four fewer matrix multiplies per minimization step relative to previous formulations. The simplified method also exhibits superior convergence properties, such that the bulk of the work may be shifted to the quadratically convergent McWeeny purification, which brings the density matrix to idempotency. Both orthogonal and nonorthogonal versions are derived. The AINV algorithm of Benzi, Meyer, and T (u) over circle ma [SIAM J. Sci. Comp. 17, 1135 (1996)] is introduced to linear scaling electronic structure theory, and found to be essential in transformations between orthogonal and nonorthogonal representations. These methods have been developed with an atom- blocked sparse matrix algebra that achieves sustained megafloating point operations per second rates as high as 50% of theoretical, and implemented in the MondoSCF suite of linear scaling SCF programs. For the first time, linear scaling Hartree-Fock theory is demonstrated with three- dimensional systems, including water clusters and estane polymers. The nonorthogonal minimization is shown to be uncompetitive with minimization in an orthonormal representation. An early onset of linear scaling is found for both minimal and double zeta basis sets, and crossovers with a highly optimized eigensolver are achieved. Calculations with up to 6000 basis functions are reported. The scaling of errors with system size is investigated for various levels of approximation. (C) 1999 American Institute of Physics. [S0021-9606(99)30702-9]. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Grp T12, Los Alamos, NM 87545 USA. RP Challacombe, M (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Grp T12, MS B268, Los Alamos, NM 87545 USA. EM MChalla@T12.LANL.Gov NR 95 TC 170 Z9 170 U1 0 U2 17 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 1 PY 1999 VL 110 IS 5 BP 2332 EP 2342 DI 10.1063/1.477969 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 161ET UT WOS:000078276500005 ER PT J AU Kaiser, RI Ochsenfeld, C Head-Gordon, M Lee, YT AF Kaiser, RI Ochsenfeld, C Head-Gordon, M Lee, YT TI Crossed-beam reaction of carbon atoms with sulfur containing molecules. I. Chemical dynamics of thioformyl (HCS X(2)A ') formation from reaction of C(P-3(j)) with hydrogen sulfide, H2S(X(1)A(1)) SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID GAUSSIAN-BASIS SETS; HYDROCARBON MOLECULES; INTERSTELLAR CLOUDS; CHEMISTRY; STATES; H2CS; THIOFORMALDEHYDE; SPECTROSCOPY; ABUNDANCES; ENERGIES AB The reaction between ground state carbon atoms, C(P-3(j)), and hydrogen sulfide, H2S(X(1)A(1)), was studied at four average collision energies between 16.7 and 42.8 kJ mol(-1) using the crossed molecular beam technique. The reaction dynamics were deducted from time- of- flight spectra and from laboratory angular distributions combined with ab initio calculations. These data suggest that the reaction proceeds through an addition of C(P-3(j)) to the sulfur atom to form a triplet CSH2 van der Waals complex. Successive H atom migration on the triplet or singlet surface forms a thiohydroxycarbene intermediate, HCSH, which decomposes through a tight exit transition state to HCS (X(2)A') + H(S-2(1/2)). At lower collision energies, a weak L-L' coupling leads to isotropic center-of-mass angular distributions. As the collision energy rises, the angular distributions show increasing forward scattering thereby documenting that the reaction goes through an osculating HCSH complex. Identification of the HCS isomer under single collision conditions is a potential one- step pathway by which to form organo-sulfur molecules in interstellar environments during the collision of the comet Shoemaker-Levy 9 with Jupiter, and in combustion flames of sulfur containing fuels. (C) 1999 American Institute of Physics. [S0021-9606(99)01205-2]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Kaiser, RI (reprint author), Acad Sinica, Inst Atom & Mol Sci, 1,Sec 4,Roossevelt Rd, Taipei 106, Taiwan. EM kaiser@po.iams.sinica.edu.tw; chi@alcatraz.cchem.berkeley.edu; mhg@alcatraz.cchem.berkeley.edu; ytlee@gate.sinica.edu.tw RI Lee, Yuan-Tseh/F-7914-2012; Ochsenfeld, Christian/E-8021-2015 OI Ochsenfeld, Christian/0000-0002-4189-6558 NR 45 TC 26 Z9 27 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 1 PY 1999 VL 110 IS 5 BP 2391 EP 2403 DI 10.1063/1.477944 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 161ET UT WOS:000078276500011 ER PT J AU Liu, L Muckerman, JT AF Liu, L Muckerman, JT TI Strong-field optical control of vibrational dynamics: Vibrational Stark effect in planar acetylene SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SELECTIVE INFRARED EXCITATION; PHASE AB We perform quantum mechanical simulations of vibrational excitation of planar (5D) acetylene (HCCH) with linearly polarized, intense but nonionizing, infrared laser pulses, exploring one particular pathway for exciting the HCCH molecule into a CC-stretching state via the fundamental excitation in a two-pulse scheme. We optimize the pulse widths, time centers, and carrier frequencies of the two pulses to achieve the maximal projection onto the target CC-stretching state, (0,3,0,0,0) A(1), subject to penalties related to peak electric field and pulse duration. The influences of Fermi resonance, the vibrational Stark effect, and avoided crossings on the selective excitation are discussed. Different sizes of "essential-states" representation are used and checked against the underlying 299 475-point discrete variable representation (DVR) basis. We find that an essential- states basis consisting of 362 A(1) and B-2 eigenstates represents the results of a full- grid calculation for the excitation process under study. Moreover, we demonstrate that despite the complications associated with the higher dimensionality of the 5D model, we can nevertheless exert infrared laser control over the vibrational dynamics of selective excitation. (C) 1999 American Institute of Physics. [S0021-9606(98)00540-6]. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Liu, L (reprint author), Brookhaven Natl Lab, Dept Chem, POB 5000, Upton, NY 11973 USA. RI Muckerman, James/D-8752-2013 NR 17 TC 12 Z9 12 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 1 PY 1999 VL 110 IS 5 BP 2446 EP 2451 DI 10.1063/1.477950 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 161ET UT WOS:000078276500018 ER PT J AU Shi, ZT Afzal, V Coller, B Patel, D Chasis, JA Parra, M Lee, G Paszty, C Stevens, M Walensky, L Peters, LL Mohandas, N Rubin, E Conboy, JG AF Shi, ZT Afzal, V Coller, B Patel, D Chasis, JA Parra, M Lee, G Paszty, C Stevens, M Walensky, L Peters, LL Mohandas, N Rubin, E Conboy, JG TI Protein 4.1R-deficient mice are viable but have erythroid membrane skeleton abnormalities SO JOURNAL OF CLINICAL INVESTIGATION LA English DT Article ID SPECTRIN-ACTIN-BINDING; HEREDITARY ELLIPTOCYTOSIS; STRUCTURAL PROTEIN-4.1; TERNARY COMPLEX; MESSENGER-RNA; BAND 4.1; CELLS; EXPRESSION; DIFFERENTIATION; ERYTHROPOIESIS AB A diverse family of protein 4.1R isoforms is encoded by a complex gene on human chromosome 1. Although the prototypical 80-kDa 4.1R in mature erythrocytes is a key component of the erythroid membrane skeleton that regulates erythrocyte morphology and mechanical stability, little is known about 4.1R function in nucleated cells. Using gene knockout technology, we have generated mice with complete deficiency of all 4.1R protein isoforms. These 4.1R-null mice were viable, with moderate hemolytic anemia but no gross abnormalities. Erythrocytes from these mice exhibited abnormal morphology, lowered membrane stability, and reduced expression of other skeletal proteins including spectrin and ankyrin, suggesting that loss of 4.1R compromises membrane skeleton assembly in erythroid progenitors. Platelet morphology and function were essentially normal, indicating that 4.1R deficiency may have less impact on other hematopoietic lineages. Nonerythroid 4.1R expression patterns, viewed using histochemical staining for lacZ reporter activity incorporated into the targeted gene, revealed focal expression in specific neurons in the brain and in select cells of other major organs, challenging the view that 4.1R expression is widespread among nonerythroid cells. The 4.1R knockout mice represent a valuable animal model for exploring 4.1R function in nonerythroid cells and for determining pathophysiological sequelae to 4.1R deficiency. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. CUNY Mt Sinai Sch Med, Dept Med, New York, NY 10029 USA. Johns Hopkins Univ, Sch Med, Dept Neurosci, Baltimore, MD 21205 USA. Jackson Lab, Bar Harbor, ME 04609 USA. RP Conboy, JG (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Bldg 74-157,1 Cyclotron Rd, Berkeley, CA 94720 USA. EM jgconboy@lbl.gov FU NHLBI NIH HHS [HL55321, R01 HL055321]; NIDDK NIH HHS [DK32094, P01 DK032094] NR 45 TC 94 Z9 96 U1 0 U2 0 PU AMER SOC CLINICAL INVESTIGATION INC PI ANN ARBOR PA ROOM 4570 KRESGE I, 200 ZINA PITCHER PLACE, ANN ARBOR, MI 48109-0560 USA SN 0021-9738 J9 J CLIN INVEST JI J. Clin. Invest. PD FEB PY 1999 VL 103 IS 3 BP 331 EP 340 DI 10.1172/JCI3858 PG 10 WC Medicine, Research & Experimental SC Research & Experimental Medicine GA 166MX UT WOS:000078581400005 PM 9927493 ER PT J AU Goldberg, LA MacKenzie, PD AF Goldberg, LA MacKenzie, PD TI Analysis of practical backoff protocols for contention resolution with multiple servers SO JOURNAL OF COMPUTER AND SYSTEM SCIENCES LA English DT Article AB Backoff protocols are probably the most widely used protocols for contention resolution in multiple access channels. In this paper, we analyze the stochastic behavior of backoff protocols for contention resolution among a set of clients and servers. each server being a multiple access channel that deals with contention like an ethernet channel, We use the standard model in which each client generates requests for a given server according to a Bernoulli distribution with a specified mean. The client-server request rate of a system is the maximum over all client-server pairs ( i, j) of the sum of all request rates associated with either client i or server j, (Having a subunit client-server request rate is a necessary condition for stability for single-server systems.) Our main result is that any superlinear polynomial backoff protocol is stable for any multiple-server system with a subunit client-server request rate. Our result is the first proof of stability for any backoff protocol for contention resolution with multiple servers, (The multiple-server problem does not reduce to the single-server problem, because each client can only send a single message at any step.) Our result is also the first proof that any weakly acknowledgment based protocol is stable for contention resolution with multiple servers and such high request rates. Two special cases of our result are of interest. Hastad, Leighton, acid Rogoff have shown that for a single-server system with a subunit client-server request rate any modified superlinear polynomial backoff protocol is stable. These modified backoff protocols are similar to standard backoff protocols but require more random bits to implement. The special case of our result in which there is only one server extends the result of Hastad, Leighton, and Rogoff to standard (practical) backoff protocols. Finally, our result applies to dynamic routing in optical networks. Specifically, a special case of our result demonstrates that superlinear polynomial backoff protocols are stable for dynamic routing in optical networks. (C) 1999 Academic Press. C1 Univ Warwick, Dept Comp Sci, Coventry CV4 7AL, W Midlands, England. Boise State Univ, Dept Math & Comp Sci, Boise, ID 83725 USA. Sandia Natl Labs, Livermore, CA 94550 USA. RP Goldberg, LA (reprint author), Univ Warwick, Dept Comp Sci, Coventry CV4 7AL, W Midlands, England. NR 7 TC 19 Z9 20 U1 0 U2 0 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-0000 J9 J COMPUT SYST SCI JI J. Comput. Syst. Sci. PD FEB PY 1999 VL 58 IS 1 BP 232 EP 258 DI 10.1006/jcss.1998.1590 PG 27 WC Computer Science, Hardware & Architecture; Computer Science, Theory & Methods SC Computer Science GA 170AN UT WOS:000078783100021 ER PT J AU Chang, NB Kao, CYJ Wei, YL Tseng, CC AF Chang, NB Kao, CYJ Wei, YL Tseng, CC TI Comparative study of 3D numerical and puff models for dense air pollutants SO JOURNAL OF ENVIRONMENTAL ENGINEERING LA English DT Article ID 4-DIMENSIONAL DATA ASSIMILATION; TURBULENCE CLOSURE-MODEL; SIMULATIONS AB To prepare for a chemical emergency response program in those industrial cities that might involve a release of chemical contaminants to the atmosphere, we have adopted a series of source emission models and a three-dimensional atmospheric model along with its companion diffusion module for predicting the dispersion and concentrations of these hazardous chemicals with various types of release scenarios. The three-dimensional atmospheric model predicts the wind, temperature, and turbulence fields in which the physical processes associated with terrain, clouds, radiation, and surface vegetation are included. The analytical framework is designed by the fact that the diffusion module uses the estimated release rate from a source emission model and the predicted winds and turbulence conditions from the atmospheric model to compute particle trajectories, concentrations, and dosages in the area of a release. In addition, the model results have been coupled with the geographical information system, which may be used for risk assessment at the urban industrial area of south Taiwan by emergency planners. C1 Natl Cheng Kung Univ, Dept Environm Engn, Tainan 70101, Taiwan. Los Alamos Natl Lab, Div Earth & Environm Sci, Los Alamos, NM 87545 USA. RP Natl Cheng Kung Univ, Dept Environm Engn, Tainan 70101, Taiwan. NR 24 TC 1 Z9 1 U1 0 U2 3 PU ASCE-AMER SOC CIVIL ENGINEERS PI RESTON PA 1801 ALEXANDER BELL DR, RESTON, VA 20191-4400 USA SN 0733-9372 EI 1943-7870 J9 J ENVIRON ENG JI J. Environ. Eng.-ASCE PD FEB PY 1999 VL 125 IS 2 BP 175 EP 184 DI 10.1061/(ASCE)0733-9372(1999)125:2(175) PG 10 WC Engineering, Environmental; Engineering, Civil; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 157TQ UT WOS:000078078100010 ER PT J AU McMasters, RL Beck, JV Dinwiddie, RB Wang, H AF McMasters, RL Beck, JV Dinwiddie, RB Wang, H TI Accounting for penetration of laser heating in flash thermal diffusivity experiments SO JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME LA English DT Article DE absorption; conduction; heat transfer; inverse; properties; radiation AB Since the early 1960s, the laser flash method of thermal diffusivity measurement has been used on a large variety of materials. Several parameter estimation methods have also been used in analyzing such experiments, employing various levels of sophistication. Estimation of thermal parameters, using the models developed as part of this research, is performed on experimental data from the Oak Ridge National Laboratory in Oak Ridge, TN. The material used is carbon bonded carbon fiber (CBCF) which is designed as an insulating material for atmosphere re-entry applications. Ambient temperatures in the experiments range from 800 degrees C to 1200 degrees C. The approximate thermal diffusivity of the material is 0.3 mm(2)/sec. This research investi gates the penetration of the laser flash beyond the surface of the material being heated. Three heat transfer models are presented, each with different assumptions about the initial temperature distribution inside the material. An evaluation is made of the response of the methods to factors which may enter into the experimental process. This is done in quantitative terms so as to assess the adequacy of the models in comparison to one another. C1 Michigan State Univ, Dept Mech Engn, E Lansing, MI 48824 USA. Oak Ridge Natl Lab, High Temp Mat Lab, Oak Ridge, TN 37831 USA. RP McMasters, RL (reprint author), Michigan State Univ, Dept Mech Engn, E Lansing, MI 48824 USA. RI Wang, Hsin/A-1942-2013 OI Wang, Hsin/0000-0003-2426-9867 NR 13 TC 10 Z9 10 U1 0 U2 1 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0022-1481 J9 J HEAT TRANS-T ASME JI J. Heat Transf.-Trans. ASME PD FEB PY 1999 VL 121 IS 1 BP 15 EP 21 DI 10.1115/1.2825929 PG 7 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 177TP UT WOS:000079227400003 ER PT J AU Ammerman, CN You, SM AF Ammerman, CN You, SM TI Consecutive-photo method to measure vapor volume flow rate during boiling from a wire immersed in saturated liquid - Authors' closure SO JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME LA English DT Editorial Material RP Ammerman, CN (reprint author), Univ Calif Los Alamos Natl Lab, ESA DE, POB 1663, Los Alamos, NM 87545 USA. NR 8 TC 0 Z9 0 U1 1 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0022-1481 J9 J HEAT TRANS-T ASME JI J. Heat Transf.-Trans. ASME PD FEB PY 1999 VL 121 IS 1 BP 246 EP 247 DI 10.1115/1.2825960 PG 2 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 177TP UT WOS:000079227400044 ER PT J AU Kastner, JR Jones, WJ Roberts, RS AF Kastner, JR Jones, WJ Roberts, RS TI Ethanol fermentation of mixed-sugars using a two-phase, fed-batch process: method to minimize D-glucose repression of Candida shehatae D-xylose fermentations SO JOURNAL OF INDUSTRIAL MICROBIOLOGY & BIOTECHNOLOGY LA English DT Article DE D-xylose; mixed-sugars; fermentation; fed-batch; viability; Candida shehatae ID PICHIA-STIPITIS; VIABILITY; TEMPERATURE; METABOLISM; TRANSPORT; YEASTS; PH AB Candida shehatae cells pre-grown on D-xylose simultaneously consumed mixtures of D-xylose and D-glucose, under both non-growing (anoxic) and actively growing conditions (aerobic), to produce ethanol, The rate of D-glucose consumption was independent of the D-xylose concentration for cells induced on D-xylose. However, the D-xylose consumption rate was approximately three times lower than the D-glucose consumption rate at a 50% D-glucose: 50% D-xylose mixture. Repression was not observed (substrate utilization rates were approximately equal) when the percentage of D-glucose and D-xylose was changed to 22% and 78%, respectively. In fermentations with actively growing cells (50% glucose and D-xylose), ethanol yields from o-xylose increased, the % D-xylose utilized increased, and the xylitol yield was significantly reduced in the presence of D-glucose, compared to anoxic fermentations (Y-ETOH,Y-xylose = 0.2-0.40 g g(-1), 75-100%, and Y-xylltol = 0-0.2 g g(-1) compared to Y-ETOH,Y-xylose = 0.15 g g(-1), 56%, Y-xylitol = 0.51 g g(-1), respectively). To increase ethanol levels and reduce process time, fed-batch fermentations were performed in a single stage reactor employing two phases: (1) rapid aerobic growth on D-xylose (mu = 0.32 h(-1)) to high cell densities; (2) D-glucose addition and anaerobic conditions to produce ethanol (Y-ETOH/xylose = 0.23 g g(-1)). The process generated high cell densities, 2 x 10(9) cells ml(-1), and produced 45-50 g L-1 ethanol within 50 h from a mixture of D-glucose and D-xylose (compared to 30 g L-1 in 80 h in the best batch process). The two-phase process minimized loss of cell viability, increased D-xylose utilization, reduced process time, and increased final ethanol levers compared to the batch process. C1 Georgia Inst Technol, Sch Biol, Atlanta, GA 30332 USA. Georgia Inst Technol, Sch Chem Engn, Atlanta, GA 30332 USA. RP Kastner, JR (reprint author), Savannah River Technol Ctr, Bldg 704-8T, Aiken, SC 29808 USA. RI Kastner, James/C-6289-2014 NR 13 TC 7 Z9 7 U1 0 U2 2 PU STOCKTON PRESS PI BASINGSTOKE PA HOUNDMILLS, BASINGSTOKE RG21 6XS, HAMPSHIRE, ENGLAND SN 1367-5435 J9 J IND MICROBIOL BIOT JI J. Ind. Microbiol. Biotechnol. PD FEB PY 1999 VL 22 IS 2 BP 65 EP 70 DI 10.1038/sj.jim.2900608 PG 6 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA 200PG UT WOS:000080548400001 ER PT J AU Macnaughton, SJ Cormier, MR Jenkins, TL Davis, GA White, DC AF Macnaughton, SJ Cormier, MR Jenkins, TL Davis, GA White, DC TI Quantitative sampling of indoor air biomass by signature lipid biomarker analysis SO JOURNAL OF INDUSTRIAL MICROBIOLOGY & BIOTECHNOLOGY LA English DT Article DE airborne bacteria; phospholipid fatty acids; human health ID CHROMATOGRAPHY MASS-SPECTROMETRY; FATTY-ACIDS; MICROBIAL BIOMASS; MURAMIC ACID; ORGANIC DUST; VALIDATION; SEDIMENTS; BACTERIA; EXPOSURE; SYSTEM AB Exposure to airborne biocontaminants may result in a multitude of health effects and is related to a pronounced increase in adult-onset asthma. Established culture-based procedures for quantifying microbial biomass from airborne environments have severe limitations. Assay of the phospholipid fatty acid (PLFA) components of airborne microorganisms provides a quantitative method to define biomass, community composition and nutritional/physiological activity of the microbial community. By collecting airborne particulate matter from a high volume via filtration, we collected sufficient biomass for quantitative PLFA analysis. Comparing high (filtration)and low (impaction) volume air sampling techniques at 26 locations within the Eastern United States, we determined that PLFA analysis provided a viable alternative to the established but flawed culture-based techniques for measuring airborne microbial biomass and community composition. Compared to the PLFA analysis, the culture techniques underestimated the actual viable airborne biomass present by between one to three orders of magnitude. A case study of a manufacturing plant at which there had been complaints regarding the indoor air quality is presented. Phospholipid fatty acid characterization of the biomass enabled contamination point source determination. In comparison with samples taken outdoors, increases in the relative proportion of trans PLFA, reflecting shifts in the physiological status of viable airborne Gram-negative bacteria, were detected in the indoor air samples at a majority of sampling sites. C1 Ctr Environm Biotechnol, Knoxville, TN 37932 USA. Microbiol Insights Inc, Rockford, TN 37853 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37983 USA. RP White, DC (reprint author), Ctr Environm Biotechnol, 10515 Res Dr,Suite 300, Knoxville, TN 37932 USA. NR 44 TC 5 Z9 5 U1 1 U2 3 PU STOCKTON PRESS PI BASINGSTOKE PA HOUNDMILLS, BASINGSTOKE RG21 6XS, HAMPSHIRE, ENGLAND SN 1367-5435 J9 J IND MICROBIOL BIOT JI J. Ind. Microbiol. Biotechnol. PD FEB PY 1999 VL 22 IS 2 BP 80 EP 87 DI 10.1038/sj.jim.2900609 PG 8 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA 200PG UT WOS:000080548400004 ER PT J AU Helgesen, G Conover, MJ Gibbs, D Flynn, CP AF Helgesen, G Conover, MJ Gibbs, D Flynn, CP TI Magnetic and structural measurements of lattice-matched erbium films on sapphire [110] and [001] substrates SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article DE thin films; magnetic X-ray scattering; magnetization; epitaxial strain; lock-in transitions ID X-RAY-SCATTERING; ER THIN-FILMS; EXCHANGE SCATTERING; RESONANCE; SUPERLATTICES; POLARIZATION; HOLMIUM AB The results of X-ray scattering and SQUID magnetization studies of three thin erbium films (thickness greater than or equal to 1000 Angstrom) grown epitaxially on Lu0.6Y0.4 alloy layers with differently oriented sapphire substrates are presented. The alloy composition was chosen to match the average a-axis lattice constant of bulk erbium at room temperature in order to reduce the epitaxial strain at the film interfaces. Measurements of the temperature dependence of the c- and a-axis lattice constants, magnetic wave vectors, and the magnetization of the films are reported. The qualitative features of the magnetic phase behavior are similar to what is found in other thin erbium films and in thicker, bulk samples. However, at low temperatures there are differences in detail among films grown on [110] and [001] sapphire substrates. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Inst Energy Technol, N-2007 Kjeller, Norway. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Helgesen, G (reprint author), Inst Energy Technol, POB 40, N-2007 Kjeller, Norway. NR 16 TC 2 Z9 2 U1 0 U2 4 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 FEB PY 1999 VL 192 IS 1 BP 11 EP 18 DI 10.1016/S0304-8853(98)00371-0 PG 8 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 161LG UT WOS:000078289900002 ER PT J AU Grechnev, GE Panfilov, AS Svechkarev, IV Delin, A Johansson, B Wills, JM Eriksson, O AF Grechnev, GE Panfilov, AS Svechkarev, IV Delin, A Johansson, B Wills, JM Eriksson, O TI Magnetovolume effect in UGa3 SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article DE magnetovolume effect; antiferromagnetic compounds; Neel temperature ID FIELD-INDUCED MAGNETISM; NONMAGNETIC TRANSITION; ELECTRONIC-STRUCTURE; URANIUM-COMPOUNDS; BRILLOUIN-ZONE; SPECIAL POINTS; SYSTEMS; BAND; PRESSURE; SUPERCONDUCTIVITY AB The magnetic susceptibility chi of the itinerant antiferromagnetic compound UGa3 has been studied experimentally under pressure up to, kbar in the temperature range 64-300 K. This study reveals a pronounced pressure effect on magnetic properties of UGa3 and the measured pressure derivative of the Neel temperature is found to be dT(N)/dP = -1.1 K/kbar. In order to analyze the experimental magnetovolume effect, to be specific d ln chi/d ln V, the volume dependent electronic structure of UGa3 has been calculated ab initio in the paramagnetic phase by employing a relativistic full-potential LMTO method. The effect of the external magnetic field was included self-consistently by means of the Zeeman operator, as well as orbital polarization. The calculations have brought out a predominance of itinerant uranium 5f states at the Fermi energy, as well as large and competing orbital and spin contributions to chi. The calculated field-induced magnetic moment of UGa3 and its volume derivative compare favorably with our experimental results. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Ukrainian Acad Sci, B Verkin Inst Low Temp Phys & Engn, UA-310164 Kharkov, Ukraine. Univ Uppsala, Dept Phys, Condensed Matter Theory Grp, S-75121 Uppsala, Sweden. Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87544 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87544 USA. RP Grechnev, GE (reprint author), Ukrainian Acad Sci, B Verkin Inst Low Temp Phys & Engn, 47 Lenin Ave, UA-310164 Kharkov, Ukraine. RI Grechnev, Gennadiy/E-7781-2011; Eriksson, Olle/E-3265-2014; Delin, Anna/P-2100-2014; OI Eriksson, Olle/0000-0001-5111-1374; Delin, Anna/0000-0001-7788-6127; Grechnev, Gennadiy/0000-0003-0547-2309 NR 38 TC 18 Z9 18 U1 1 U2 2 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 FEB PY 1999 VL 192 IS 1 BP 137 EP 147 DI 10.1016/S0304-8853(98)00372-2 PG 11 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 161LG UT WOS:000078289900019 ER PT J AU Stori, JA Wright, PK King, C AF Stori, JA Wright, PK King, C TI Integration of process simulation in machining parameter optimization SO JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article ID SELECTION; SYSTEMS; MODEL AB In recent years, simulation tools have proven valuable for the prediction of machining slate variables over a wide range of operating parameters. Such simulation packages, however, are seldom an integral part of machining parameter optimization modules. This paper proposes a methodology for incorporating simulation feedback to fine-tune analytic models during the optimization process. Through a limited number of calls to the computationally expensive simulation tools, process parameters,nay be generated that satisfy the design constraints within the accuracy of the simulation predictions, while providing an efficient balance among parameters arising from the functional form of the optimization model. The following iterative algorithm is presented: (i) a non-linens programming (NLP) optimization technique is used to select process parameters based on closed-form analytical constraint equations relating to critical design requirements. (ii) the simulation is executed using these process parameters, providing predictions of the critical state variables. (iii) Constraint equation parameters are dynamically adapted using the feedback provided by the simulation predictions. This sequence is repeated until local convergence between the simulation and constraint equation predictions has been achieved. A case study in machining parameter optimization for peripheral finish milling operations is developed in which constraints on the allowable form error, Delta, and the peripheral surface roughness, R-a, drive the process pameter selection for a cutting operation intended to maximize the material removal rate. Results from twenty machining scenarios are presented, including five workpiece/tool material combinations at four levels of precision. Achieving agreement (within a 5% deviation tolerance) between the simulation and constraint equation predictions required an average of 5 simulation execution cycles (maximum of 8), demonstrating promise that simulation tools can be efficiently incorporated into parameter optimization processes. C1 Univ Illinois, Dept Mech & Ind Engn, Urbana, IL 61801 USA. Univ Calif Berkeley, Dept Mech Engn, Berkeley, CA 94720 USA. Sandia Natl Labs, Integrated Mfg Syst Ctr, Livermore, CA 94551 USA. RP Stori, JA (reprint author), Univ Illinois, Dept Mech & Ind Engn, 1206 W Green St, Urbana, IL 61801 USA. NR 35 TC 14 Z9 14 U1 0 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1087-1357 J9 J MANUF SCI E-T ASME JI J. Manuf. Sci. Eng.-Trans. ASME PD FEB PY 1999 VL 121 IS 1 BP 134 EP 143 DI 10.1115/1.2830565 PG 10 WC Engineering, Manufacturing; Engineering, Mechanical SC Engineering GA 170XP UT WOS:000078832600020 ER PT J AU Rawers, JC Harlow, DG AF Rawers, JC Harlow, DG TI Understanding the strength of hot-pressed nanostructured powder compacts SO JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE LA English DT Article DE compact; nanostructure; properties; statistics; strength; Weibull distributions ID FE-AL; CONSOLIDATION; MICROSTRUCTURE; ALLOYS AB Attrition-milled nanostructured powders were hot pressed, and macroscopic properties of density, hardness, grain size, and strength were measured. No correlation was found between processing conditions (temperature and time) used in this study and compact properties, nor was a correlation found between the tensile (or failure) stress and density, hardness, or grain size. Variations of compact properties of unmilled powder were similar to that of milled powders. Tensile data were not well fitted to a Gaussian distribution but were well fitted to a two-parameter Weibull distribution, Thus, although the milled powder compacts had an average tensile strength greater than the unmilled powder compacts, all sample compositions fit a distribution with zero as a possible minimal stress level. Weibull analysis suggests that the tensile and compression strength is controlled by the presence of fine cracks, which may limit future engineering applications. Efforts to eliminate these cracks during hot pressing were unsuccessful. C1 US DOE, Albany Res Ctr, Albany, OR 97321 USA. Lehigh Univ, Bethlehem, PA 18015 USA. RP Rawers, JC (reprint author), US DOE, Albany Res Ctr, Albany, OR 97321 USA. NR 25 TC 2 Z9 3 U1 0 U2 1 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 1059-9495 J9 J MATER ENG PERFORM JI J. Mater. Eng. Perform. PD FEB PY 1999 VL 8 IS 1 BP 35 EP 45 DI 10.1361/105994999770347142 PG 11 WC Materials Science, Multidisciplinary SC Materials Science GA 177TL UT WOS:000079227100003 ER PT J AU Zhu, YT Peterson, EJ Baldonado, PS Coulter, JY Peterson, DE Mueller, FM AF Zhu, YT Peterson, EJ Baldonado, PS Coulter, JY Peterson, DE Mueller, FM TI Synthesis and crystal chemistry of the new compounds GdBa4Cu3O8.5+delta and DyBa4Cu3O8.5+delta SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID SYSTEM AB Two new compounds, GdBa4Cu3O8.5+delta (Gd143), and DyBa4Cu3O8.5+delta (Dy143), were synthesized from precursors Gd2O3, DY2O3, BaO2, and CuO at 1000 degrees C in an oxygen atmosphere. The oxygen stoichiometric value delta was found to be 0.68 for Gd143 and 0.6 for Dy143 by iodometric titration. Rietveld refinement of x-ray powder diffraction data showed that Gd143 belongs to the space group Pm3 while Dy143 belongs to the space group P23. The two space groups, Pm3 and P23, are very similar. Their main difference is that P23 does not have the inversion symmetry of Pm3. Both compounds have a cubic unit cell with a lattice parameter of 8.16528 +/- 0.00006 Angstrom for Gd143 and 8.10807 +/- 0.00010 Angstrom for Dy143. Superconducting quantum interference device (SQUID) measurement indicated that neither compound was superconductive down to 5 K. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Zhu, YT (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Mail Stop K763, Los Alamos, NM 87545 USA. RI Zhu, Yuntian/B-3021-2008 OI Zhu, Yuntian/0000-0002-5961-7422 NR 7 TC 7 Z9 7 U1 1 U2 4 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD FEB PY 1999 VL 14 IS 2 BP 334 EP 339 DI 10.1557/JMR.1999.0049 PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA 235PA UT WOS:000082550200006 ER PT J AU Anderson, JW Dorris, SE Parrell, JA Larbalestier, DC AF Anderson, JW Dorris, SE Parrell, JA Larbalestier, DC TI The effect of lead content on the critical current density, irreversibility field, and microstructure of Ag-clad Bi0.8PbxSr2Ca2Cu3Oy tapes SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID CA-CU-O; HIGH-TC PHASE; BSCCO-2223 TAPES; (BI,PB)(2)SR2CA2CU3OX TAPES; REACTION-MECHANISM; SUPERCONDUCTING PROPERTIES; SINGLE-CRYSTALS; COOLING RATE; PB; BI AB We studied the effect of lead content (x = 0.20-0.40) on the critical current density J(c) (0 T, 77 K), irreversibility field H* (77 K), and microstructure of monocore, Ag-clad Bi(1.8)Pbx Sr2Ca2Cu3Oy (2223) tapes, finding that tapes with lower lead contents (x = 0.20-0.25) required higher processing temperatures (840 and 832 degrees C, respectively) to complete 2223 formation, as compared to the optimum 820 degrees C reaction temperature of the x = 0.30-0.40 tapes. We found that both the zero-field and the in-field properties correlated strongly to the phase purity with J(c) (0 T, 77 K) reaching a maximum of similar to 20 kA/cm(2) for x = 0.30, and then decreasing with increasing lead content to similar to 12 kA/cm(2) for x = 0.40. H* (77 K) increased from similar to 165 mT at x = 0.20 to similar to 265 mT at x = 0.30, then declined to 195 mT at x = 0.40. Optimizing the lead content at x = 0.30 maximized both the connectivity and the flux pinning contributions to the critical current density. C1 Univ Wisconsin, Ctr Appl Superconduct, Madison, WI 53706 USA. Univ Wisconsin, Mat Sci Program, Madison, WI 53706 USA. Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. RP Anderson, JW (reprint author), Motorola Inc, 3501 Ed Bluestein Blvd, Austin, TX 78721 USA. RI Larbalestier, David/B-2277-2008 OI Larbalestier, David/0000-0001-7098-7208 NR 41 TC 21 Z9 21 U1 0 U2 1 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 FEB PY 1999 VL 14 IS 2 BP 340 EP 348 PG 9 WC Materials Science, Multidisciplinary SC Materials Science GA 235PA UT WOS:000082550200007 ER PT J AU Lowndes, DH Rouleau, CM Thundat, TG Duscher, G Kenik, EA Pennycook, SJ AF Lowndes, DH Rouleau, CM Thundat, TG Duscher, G Kenik, EA Pennycook, SJ TI Silicon and zinc telluride nanoparticles synthesized by low energy density pulsed laser ablation into ambient gases SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID LIGHT-EMISSION; THIN-FILM; INERT-GAS; GROWTH; FABRICATION; ABSORPTION; DEPOSITION; PARTICLES; PRESSURE; SIZE AB The size distributions of Si and ZnTe nanoparticles produced by low energy density ArF (193 nm) pulsed laser ablation into ambient gases were measured as a function of the gas pressure, P, and target-substrate separation, D-ts. For both Si and ZnTe, the largest nanoparticles were found closest to the ablation target, and the mean nanoparticle size decreased with increasing D-ts. For Si ablation into He, the mean nanoparticle diameter did not increase monotonically with gas pressure but reached a maximum near P = 6 Torr. High resolution Z-contrast transmission electron microscopy and energy loss spectroscopy revealed that ZnTe nanoparticles consist of a crystalline core surrounded by an amorphous ZnO shell; growth defects and surface steps are clearly visible in the crystalline core. A pronounced narrowing of the ZnTe nanocrystal size distribution with increasing D-ts also was found. The results demonstrate that the size of laser-ablated nanoparticles can be controlled by varying the molecular weight and pressure of an ambient gas and that nanometer-scale particles can be synthesized. Larger aggregates of both ZnTe and Si having a "flakelike" or "weblike" structure were formed at the higher ambient gas pressures; for ZnTe these appear to be open agglomerates of much smaller (similar to 10 nm) particles. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Lowndes, DH (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. RI Duscher, Gerd/G-1730-2014; Rouleau, Christopher/Q-2737-2015 OI Duscher, Gerd/0000-0002-2039-548X; Rouleau, Christopher/0000-0002-5488-3537 NR 25 TC 43 Z9 44 U1 0 U2 1 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 FEB PY 1999 VL 14 IS 2 BP 359 EP 370 DI 10.1557/JMR.1999.0053 PG 12 WC Materials Science, Multidisciplinary SC Materials Science GA 235PA UT WOS:000082550200010 ER PT J AU Suryanarayana, C Ivanov, E Noufi, R Contreras, MA Moore, JJ AF Suryanarayana, C Ivanov, E Noufi, R Contreras, MA Moore, JJ TI Phase selection in a mechanically alloyed Cu-In-Ga-Se powder mixture SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID CHALCOGENIDES; COPPER AB Formation of a homogeneous nanocrystalline CuIn0.7Ga0.3Se2 alloy was achieved by mechanical alloying of blended elemental Cu, In, Ga, and Se powders in a planetary ball mill. X-ray diffraction and transmission electron microscopy and diffraction techniques were employed to follow the structural evolution during milling. It was observed that, depending upon the milling conditions, either a metastable cubic or a stable tetragonal phase was produced. The grain size of the mechanically alloyed powder was about 10 nm. The mechanically alloyed powder was consolidated to full density by hot isostatic pressing the powder at 750 degrees C and 100 MPa for 2 h. irrespective of the nature of the phase in the starting powder, the hot isostatically pressed compact contained the well-crystallized tetragonal CuIn(0.7)Gao(0.3)Se(2) phase with a grain size of about 50 nm. C1 Colorado Sch Mines, Dept Met & Mat Engn, Adv Coatings & Surface Engn Lab, Golden, CO 80401 USA. Tosoh SMD Inc, Grove City, OH 43213 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Suryanarayana, C (reprint author), Colorado Sch Mines, Dept Met & Mat Engn, Adv Coatings & Surface Engn Lab, Golden, CO 80401 USA. RI Suryanarayana, C/B-9314-2008 NR 21 TC 16 Z9 16 U1 1 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 FEB PY 1999 VL 14 IS 2 BP 377 EP 383 DI 10.1557/JMR.1999.0055 PG 7 WC Materials Science, Multidisciplinary SC Materials Science GA 235PA UT WOS:000082550200012 ER PT J AU Tambwe, MF Stone, DS Griffin, AJ Kung, H Lu, YC Nastasi, M AF Tambwe, MF Stone, DS Griffin, AJ Kung, H Lu, YC Nastasi, M TI Haasen plot analysis of the Hall-Petch effect in Cu/Nb nanolayer composites SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID MECHANICAL-PROPERTIES; THIN-FILMS; THERMAL-ACTIVATION; ENHANCED HARDNESS; STRESS; CU; SUPERLATTICES; MULTILAYERS; MOLYBDENUM; STRENGTH AB We investigate the effects of layer thickness (t) on hardness (H) and rate sensitivity of the hardness (partial derivative H / partial derivative In is an element of over dot) in 1 mu m-thick Cu/Nb nanolayer composites. For t > 10 nm, we find that H correlates with t according to H = H-0 + H(1)t(-1/2), suggestive of a Hall-Fetch mechanism with layer interfaces replacing grain boundaries as barriers against dislocation motion. The measured levels of partial derivative H / partial derivative In (is an element of) over dot clearly indicate the operation of bulk-like dislocation mechanisms consistent with a Hall-Fetch mechanism. However, based on a Haasen-plot activation analysis, it appears that the Hall-Fetch coefficient, H-1, is strongly rate-dependent, inconsistent with a conventional Hall-Fetch mechanism. For specimens with t < 10 nm there is a saturation in hardness, but the rate sensitivity data indicate no clear evidence of a corresponding change in mechanism. Simple models are proposed. C1 Univ Wisconsin, Dept Mat Sci & Engn, Madison, WI 53706 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Tambwe, MF (reprint author), Univ Wisconsin, Dept Mat Sci & Engn, 1509 Univ Ave, Madison, WI 53706 USA. RI Stone, Donald/A-7496-2016 NR 48 TC 28 Z9 28 U1 0 U2 8 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 FEB PY 1999 VL 14 IS 2 BP 407 EP 417 DI 10.1557/JMR.1999.0059 PG 11 WC Materials Science, Multidisciplinary SC Materials Science GA 235PA UT WOS:000082550200016 ER PT J AU Park, ET Nash, P Wolfenstine, J Goretta, KC Routbort, JL AF Park, ET Nash, P Wolfenstine, J Goretta, KC Routbort, JL TI High-temperature creep of polycrystalline BaTiO3 SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID BARIUM-TITANATE; DEFORMATION; DIFFUSION; CERAMICS AB Compressive creep of dense BaTiO3 having linear-intercept grain sizes of 19.3-52.4 mu m was investigated at 1200-1300 degrees C by varying the oxygen partial pressure from 10(2) to 10(5) Pa in both constant-stress and constant-crosshead-velocity modes. Microstructures of the deformed materials were examined by scanning and transmission electron microscopy. The stress exponent was approximate to 1, the grain-size dependence was approximate to 1/d(2), and the activation energy was approximate to 720 kJ/mole. These parameters, combined with the microstructural observations (particularly grain displacement and absence of deformation-induced dislocations), indicated that the dominant deformation mechanism was grain-boundary sliding accommodated by lattice cation diffusion. Because of the absence of an oxygen partial pressure dependence, diffusion was probably controlled extrinsically. C1 Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. IIT, Mech Mat & Aerosp Engn Dept, Chicago, IL 60616 USA. Army Mat Lab, Adelphi, MD 20783 USA. RP Park, ET (reprint author), Argonne Natl Lab, Div Energy Technol, 9700 S Cass Ave, Argonne, IL 60439 USA. OI Nash, Philip/0000-0003-2975-8512 NR 23 TC 20 Z9 20 U1 2 U2 12 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0884-2914 EI 2044-5326 J9 J MATER RES JI J. Mater. Res. PD FEB PY 1999 VL 14 IS 2 BP 523 EP 528 DI 10.1557/JMR.1999.0075 PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA 235PA UT WOS:000082550200032 ER PT J AU He, XM Shu, L Li, HB Weng, D AF He, XM Shu, L Li, HB Weng, D TI High corrosion resistant ZrC films synthesized by ion-beam-assisted deposition SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID CARBIDE AB ZrC films with high hardness were deposited on A3 steel by ion-beam-assisted deposition and had a corrosion rate more than two orders less and a corrosion potential 0.19 V greater than those of the bare A3 steel. The corrosion current of ZrC films was 10 times less and the polarization resistance at least 7.82 times higher than those of both Teflon and ZrN films, respectively. The experimental results confirmed that ZrC films notably enhanced the corrosion resistance of steels. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. Tsing Hua Univ, Dept Mat Sci & Engn, Beijing 100084, Peoples R China. RP He, XM (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, POB 1663, Los Alamos, NM 87545 USA. NR 12 TC 10 Z9 13 U1 1 U2 8 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 FEB PY 1999 VL 14 IS 2 BP 615 EP 618 DI 10.1557/JMR.1999.0087 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA 235PA UT WOS:000082550200044 ER PT J AU Joel, DD Coderre, JA Micca, PL Nawrocky, MM AF Joel, DD Coderre, JA Micca, PL Nawrocky, MM TI Effect of dose and infusion time on the delivery of p-boronophenylalanine for neutron capture therapy SO JOURNAL OF NEURO-ONCOLOGY LA English DT Article DE neutron capture therapy; p-boronophenylalanine; rat brain tumor; 9L gliosarcoma; boron concentration; biodistribution ID RAT-BRAIN TUMORS; GLIOBLASTOMA-MULTIFORME; BORON; MELANOMA; COMPLEX AB Clinical trials of boron neutron capture therapy (BNCT) for glioblastoma multiforme are currently in progress using p-boronophenylalanine (BPA) as the B-10 delivery agent. Enhancement of tumor boron uptake and/or the tumor-to-blood (T:B) boron concentration ratio would have the potential of significantly improving the therapeutic gain of BNCT. The effects of total dose, infusion time, and route of administration of BPA on tumor and blood boron concentrations were studied in rats bearing the 9L gliosarcoma. Increasing the total dose of BPA from 250 to 1000 mg/kg, administered intravenously over a 2-h infusion period, resulted in an increase in tumor boron concentration from similar to 30 to similar to 70 mu g B-10/g, with a constant T : B boron concentration ratio of about 3.7 : 1. Similarly, extension of the infusion time from 2 to 6 h, at a constant dose-rate of 125 mg BPA/kg/h, resulted in an increase in tumor boron concentration from similar to 30 to similar to 80 mu g B-10/g, while, again, maintaining a constant T:B ratio of about 3.7 : 1. In contrast, intracarotid infusion of BPA for 1 h at a dose rate of 125 mg BPA/kg resulted in an increase in the tumor boron concentration from similar to 26 to similar to 38 mu g B-10/g with a corresponding increase in the T:B ratio from 3.5 : 1 to 5.0 : 1. The effects of these results on the therapeutic gain potentially achievable with BNCT are discussed. C1 Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. RP Coderre, JA (reprint author), Brookhaven Natl Lab, Dept Med, Bldg 490,POB 5000, Upton, NY 11973 USA. NR 27 TC 43 Z9 44 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-594X J9 J NEURO-ONCOL JI J. Neuro-Oncol. PD FEB PY 1999 VL 41 IS 3 BP 213 EP 221 DI 10.1023/A:1006176901713 PG 9 WC Oncology; Clinical Neurology SC Oncology; Neurosciences & Neurology GA 195NW UT WOS:000080258900003 PM 10359141 ER EF