FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Puso, MA AF Puso, MA TI A highly efficient enhanced assumed strain physically stabilized hexahedral element SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING LA English DT Article DE finite element; hexahedral; physical stabilization; enhanced strain ID ONE-POINT QUADRATURE; HOURGLASS CONTROL; FINITE DEFORMATIONS; SHELL ELEMENT; FORMULATION AB A method which combines the incompatible modes method with the physical stabilization method is developed to provide a highly efficient formulation for the single point eight-node hexahedral element. The resulting element is compared to well-known enhanced elements in standard benchmark type problems. It is seen that this single-point element is nearly as coarse mesh accurate as the fully integrated EAS elements. A key feature is the novel enhanced strain fields which do not require any matrix inversions to solve for the internal element degrees of freedom. This, combined with the reduction of hourglass stresses to four hourglass forces, produces an element that is only 6.5 per cent slower than the perturbation stabilized single-point brick element commonly used in many explicit finite element codes. Copyright (C) 2000 John Wiley & Sons, Ltd. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Puso, MA (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94550 USA. NR 23 TC 64 Z9 68 U1 0 U2 9 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 NOV 20 PY 2000 VL 49 IS 8 BP 1029 EP 1064 DI 10.1002/1097-0207(20001120)49:8<1029::AID-NME990>3.0.CO;2-3 PG 36 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA 367LT UT WOS:000090064300003 ER PT J AU Reitz, TL Ahmed, S Krumpelt, M Kumar, R Kung, HH AF Reitz, TL Ahmed, S Krumpelt, M Kumar, R Kung, HH TI Characterization of CuO/ZnO under oxidizing conditions for the oxidative methanol reforming reaction SO JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL LA English DT Article DE CuO/ZnO; oxidizing condition; oxidative methanol reforming reaction ID TEMPERATURE-PROGRAMMED REDUCTION; SUPPORTED PALLADIUM CATALYSTS; COPPER-BASED CATALYSTS; CUO-ZNO CATALYSTS; METHYL FORMATE; HYDROGEN; DEHYDROGENATION; CU/ZNO/AL2O3; MECHANISM AB Catalytic generation of hydrogen by the reaction of methanol with oxygen in the presence of steam over an industrial copper-zinc oxide catalyst was studied. Under differential oxygen conversion conditions, the catalyst remained in an oxidized state, and the main reaction was oxidation of methanol to carbon dioxide and water. The activity was proportional to the copper oxide surface area. The methanol consumption rate had a small positive order in methanol and oxygen (0.18th order) and was suppressed by water. The catalyst deactivated with time on stream due to agglomeration of copper oxide. As the reactor temperature increased, the rate of methanol oxidation increased, the oxygen conversion became very high, and the catalyst away from the reactor entrance became reduced. Then, a significant rate of hydrogen production was observed. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Northwestern Univ, Dept Chem Engn, Evanston, IL 60208 USA. Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. RP Reitz, TL (reprint author), Northwestern Univ, Dept Chem Engn, Evanston, IL 60208 USA. RI Kung, Harold/B-7647-2009 NR 33 TC 102 Z9 107 U1 1 U2 16 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1381-1169 J9 J MOL CATAL A-CHEM JI J. Mol. Catal. A-Chem. PD NOV 20 PY 2000 VL 162 IS 1-2 BP 275 EP 285 DI 10.1016/S1381-1169(00)00296-X PG 11 WC Chemistry, Physical SC Chemistry GA 379BN UT WOS:000165621200023 ER PT J AU Fan, TS Jing, KX Phair, L Tso, K McMahan, M Hanold, K Wozniak, GJ Moretto, LG AF Fan, TS Jing, KX Phair, L Tso, K McMahan, M Hanold, K Wozniak, GJ Moretto, LG TI Excitation functions and mass asymmetric fission barriers for compound nuclei Se-70,Se-76 SO NUCLEAR PHYSICS A LA English DT Article DE C-12(Ni-58,Ni-64,X); E=6-14 A MeV; measured sigma (Z) vs E; deduced mass asymmetric fission barriers for Se-70,Se-76; transition state fission rates ID COMPLEX-FRAGMENT EMISSION; TRANSITION-STATE RATES; SCALING LAWS; SYSTEMATICS; ENERGY; MODEL AB Excitation functions were measured for complex fragments with atomic number Z = 5-20 emitted from the compound nuclei Se-70,Se-76 produced in the reactions Ni-58,Ni-64 + C-12. Mass asymmetric fission barriers were extracted by fitting the excitation functions with a transition state formalism. The extracted barriers were compared with those calculated from macroscopic nuclear models. The measured barriers for symmetric fission seem to support the hypothesis of a shaped-dependent congruence energy, which doubles for fission of strongly indented saddle-point shapes. All of the measured excitation functions can be scaled onto a single straight line according to the transition state prediction. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Beijing Univ, Dept Tech Phys, Inst Heavy Ion Phys, Beijing 100871, Peoples R China. RP Fan, TS (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 36 TC 20 Z9 21 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD NOV 20 PY 2000 VL 679 IS 2 BP 121 EP 146 DI 10.1016/S0375-9474(00)00334-1 PG 26 WC Physics, Nuclear SC Physics GA 377KR UT WOS:000165513200001 ER PT J AU Ko, YJ Egan, JJ Kegel, GHR DeSimone, DJ Seo, PN Young, PG AF Ko, YJ Egan, JJ Kegel, GHR DeSimone, DJ Seo, PN Young, PG TI Thulium-169 neutron inelastic scattering cross section measurements via the Tm-169(n, n 'gamma) reaction SO NUCLEAR PHYSICS A LA English DT Article DE inelastic neutron scattering; nuclear reactions Tm-169(n, n ' y); gamma-branching ratios; neutron inelastic level cross sections; compound and direct nuclear interaction; time-of-flight method; high purity Ge detector AB Neutron inelastic scattering from thulium-169 has been studied for states above 100 keV via the (n, n'gamma) reaction at incident energies in the 0.2- to 1.0-MeV range. A high-resolution Ge spectrometer in conjunction with the time-of-flight technique was utilized. Thirty-six gamma-ray transitions from 16 levels were observed. Gamma-ray angular distributions were measured at E-n = 750 keV and excitation functions at 125 degrees were measured in 50 keV steps over the range of incident energies. Differential gamma-ray production cross sections and gamma-ray branching ratios were obtained. Inferred neutron inelastic level cross sections of the four lowest groundstate rotational band (K-pi = 1/2(+)) members are compared to the sum of calculated compound nucleus and direct interaction cross sections. For the remaining levels, measurements are compared to compound nucleus calculations only. The comparison shows generally good agreement particularly near threshold. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Lowell, Dept Phys & Appl Phys, Radiat Lab, Lowell, MA 01854 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Ko, YJ (reprint author), Univ Lowell, Dept Phys & Appl Phys, Radiat Lab, 1 Univ Ave, Lowell, MA 01854 USA. NR 19 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD NOV 20 PY 2000 VL 679 IS 2 BP 147 EP 162 DI 10.1016/S0375-9474(00)00340-7 PG 16 WC Physics, Nuclear SC Physics GA 377KR UT WOS:000165513200002 ER PT J AU Cheng, HC Dobrescu, BA Hill, CT AF Cheng, HC Dobrescu, BA Hill, CT TI Electroweak symmetry breaking and extra dimensions SO NUCLEAR PHYSICS B LA English DT Article ID STANDARD MODEL; HIGGS MASS; CONDENSATION; UNIFICATION; MILLIMETER; HIERARCHY; STRINGS; TEV AB Electroweak symmetry can be naturally broken by observed quark and gauge fields in various extra-dimensional configurations. No new fundamental fields are required below the quantum gravitational scale (similar to 10-100 TeV), We examine schemes in which the QCD gauge group alone, in compact extra dimensions, forms a composite Higgs doublet out of (t, b)(L) and a linear combination of the Kaluza-Klein modes of t(R), The effective theory at low energies is the Standard Model. The top-quark mass is controlled by the number of active t(R) Kaluza-Klein modes below the string scale, and is in agreement with experiment. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Fermi Natl Accelerator Lab, Dept Theoret Phys, Batavia, IL 60510 USA. Univ Calif Santa Barbara, Inst Theoret Phys, Santa Barbara, CA 93106 USA. RP Cheng, HC (reprint author), Univ Chicago, Enrico Fermi Inst, 5640 S Ellis Ave, Chicago, IL 60637 USA. NR 36 TC 74 Z9 75 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD NOV 20 PY 2000 VL 589 IS 1-2 BP 249 EP 268 DI 10.1016/S0550-3213(00)00401-6 PG 20 WC Physics, Particles & Fields SC Physics GA 370DY UT WOS:000165109100008 ER PT J AU Arkani-Hamed, N Hall, LJ Kolda, C Murayama, H AF Arkani-Hamed, N Hall, LJ Kolda, C Murayama, H TI New perspective on cosmic coincidence problems SO PHYSICAL REVIEW LETTERS LA English DT Article ID COSMOLOGICAL CONSTANT AB Cosmological data suggest that we live in an interesting period in the history of the universe when rho (Lambda) - rho (M) - rho (R). The occurrence of any epoch with such a "triple coincidence" is puzzling, while the question of why we happen to live during this special epoch is the "Why now?" problem. We introduce a framework which makes the triple coincidence inevitable; furthermore, the "Why now?" problem is transformed and greatly ameliorated. The framework assumes that the only relevant mass scales are the electroweak scale M-EW, and the Planck scale M-P1 and requires rho (1/4)(Lambda) similar to M-EW(2)/M-Pl parametrically. Assuming that the true vacuum energy vanishes, we present a simple model, where a false vacuum energy yields a cosmological constant of this form. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RP Arkani-Hamed, N (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Murayama, Hitoshi/A-4286-2011 NR 14 TC 93 Z9 93 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 NOV 20 PY 2000 VL 85 IS 21 BP 4434 EP 4437 DI 10.1103/PhysRevLett.85.4434 PG 4 WC Physics, Multidisciplinary SC Physics GA 375KU UT WOS:000165399000006 ER PT J AU Belkin, MA Kulakov, TA Ernst, KH Yan, L Shen, YR AF Belkin, MA Kulakov, TA Ernst, KH Yan, L Shen, YR TI Sum-frequency vibrational spectroscopy on chiral liquids: A novel technique to probe molecular chirality SO PHYSICAL REVIEW LETTERS LA English DT Article ID CIRCULAR-DICHROISM SPECTROSCOPY; SURFACE 2ND-HARMONIC GENERATION; 2ND HARMONIC-GENERATION AB Optical activity in sum-frequency vibrational spectra has been observed for the first time in chiral liquids. The electric-dipole allowed chiral element of the nonlinear susceptibility appears to be 3 orders of magnitude smaller than typical allowed achiral elements. This is partly because the observed chirality requires a breakdown of the Born-Oppenheimer approximation. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Shen, YR (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Belkin, Mikhail/E-9041-2013; Ernst, Karl-Heinz/O-6128-2015 OI Belkin, Mikhail/0000-0003-3172-9462; Ernst, Karl-Heinz/0000-0002-2077-4922 NR 17 TC 141 Z9 142 U1 4 U2 39 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 NOV 20 PY 2000 VL 85 IS 21 BP 4474 EP 4477 DI 10.1103/PhysRevLett.85.4474 PG 4 WC Physics, Multidisciplinary SC Physics GA 375KU UT WOS:000165399000016 PM 11082574 ER PT J AU Finn, JM Sovinec, CR del-Castillo-Negrete, D AF Finn, JM Sovinec, CR del-Castillo-Negrete, D TI Chaotic scattering and self-organization in spheromak sustainment SO PHYSICAL REVIEW LETTERS LA English DT Article ID CORONAL LOOPS; HELICITY; RECONNECTION; STATES; TIME AB Flux core spheromak sustainment by electrostatic helicity injection is studied in resistive MHD. The geometry has magnetized electrodes at the ends held at a potential difference V. For V > V-c the central current column is kink unstable. The nonlinear state with V just above V-c has a large volume of flux surfaces, with rotational transform provided by the helical kinking of the column. As V increases the kink becomes stronger, the tori are destroyed, and the field lines exhibit chaotic scattering. The distribution of field line lengths L, related to confinement and parallel current density, is studied. At larger V or larger Lundquist number S, a limit cycle appears. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Finn, JM (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, POB 1663, Los Alamos, NM 87545 USA. OI del-Castillo-Negrete, Diego/0000-0001-7183-801X NR 26 TC 17 Z9 17 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 NOV 20 PY 2000 VL 85 IS 21 BP 4538 EP 4541 DI 10.1103/PhysRevLett.85.4538 PG 4 WC Physics, Multidisciplinary SC Physics GA 375KU UT WOS:000165399000032 ER PT J AU Qiu, SR Lai, HF Than, HT Amrhein, C Yarmoff, JA AF Qiu, SR Lai, HF Than, HT Amrhein, C Yarmoff, JA TI Reaction of SeF6 with iron and iron oxide surfaces: a model for selenate reduction SO SURFACE SCIENCE LA English DT Article DE desorption induced by electron stimulation; growth; halides; iron; polycrystalline thin films; solid-gas interfaces; surface chemical reaction; X-ray photoelectron spectroscopy ID RAY PHOTOELECTRON-SPECTROSCOPY; ELECTRON-STIMULATED DESORPTION; ADSORPTION; CHEMISORPTION; GROUNDWATER; SI(111)7X7; MECHANISM; KINETICS AB The reaction of SeF6 with Fe and Fe oxide surfaces is investigated as a model of the reduction of aqueous selenate. Polycrystalline iron foils were reacted with gaseous SeF6 in vacuum and then characterized by X-ray photoelectron spectroscopy. A novel use of electron stimulated desorption was used to determine if any Se-F bonds remain following reaction. It was found that SeF6 completely dissociates, growing a film of FeF6. The growth initially follows Mott-Cabrera kinetics, but then abruptly stops. Thin Fe oxide layers on the surface impede the adsorption of SeF6. It is suggested that the fluoride and oxide films both quench the reaction by inhibiting the transport of electrons that are needed to dissociate SeF6 at the surface. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Riverside, Dept Phys, Riverside, CA 92521 USA. Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Riverside, Dept Environm Sci, Riverside, CA 92521 USA. RP Yarmoff, JA (reprint author), Univ Calif Riverside, Dept Phys, Riverside, CA 92521 USA. NR 32 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD NOV 20 PY 2000 VL 468 IS 1-3 BP 17 EP 26 DI 10.1016/S0039-6028(00)00822-0 PG 10 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 383NN UT WOS:000165889000004 ER PT J AU Soares, EA Leatherman, GS Diehl, RD Van Hove, MA AF Soares, EA Leatherman, GS Diehl, RD Van Hove, MA TI Low-energy electron diffraction study of the thermal expansion of Ag(111) SO SURFACE SCIENCE LA English DT Article DE low energy electron diffraction (LEED); silver ID MOLECULAR-SURFACE STRUCTURE; TEMPERATURE-DEPENDENCE; ANHARMONICITY; CRYSTAL AB The temperature dependence of the first three interlayer distances of the Ag(lll) surface was studied by low-energy electron diffraction (LEED) over the temperature range 128-723 K. The first three interlayer spacings and the effective Debye temperatures were extracted from the LEED analysis. At the lowest temperature, the first two interlayer spacings are slightly (0.5%) contracted. All three interlayer spacings increase with temperature. finally reaching expansions relative to the bulk of about 0.8% at the highest temperature studied. The effective surface Debye temperature is lowest for the outermost layer, increasing toward the bulk value for successive layers. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Penn State Univ, Dept Phys, University Pk, PA 16802 USA. Lawrence Berkeley Lab, Mat Sci Div, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. RP Diehl, RD (reprint author), Penn State Univ, Dept Phys, 104 Davey, University Pk, PA 16802 USA. RI Van Hove, Michel/A-9862-2008; Soares, Edmar/C-2303-2013 OI Van Hove, Michel/0000-0002-8898-6921; NR 32 TC 21 Z9 21 U1 2 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD NOV 20 PY 2000 VL 468 IS 1-3 BP 129 EP 136 DI 10.1016/S0039-6028(00)00806-2 PG 8 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 383NN UT WOS:000165889000015 ER PT J AU Kendrick, BK Mead, CA Truhlar, DG AF Kendrick, BK Mead, CA Truhlar, DG TI On the nonexistence of strictly diabatic molecular electronic bases SO CHEMICAL PHYSICS LETTERS LA English DT Article AB In a recent publication (M. Baer, A. Alijah, Chem. Phys. Lett. 319 (2000) 489), it is proposed that, contrary to a number of statements in the literature, it may indeed be possible to construct strictly diabatic electronic basis sets in molecular systems. We show that the result of Baer and Alijah is invalid. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Minnesota, Dept Chem, Minneapolis, MN 55455 USA. Univ Minnesota, Inst Supercomp, Minneapolis, MN 55455 USA. RP Mead, CA (reprint author), G2 Bartram Rd, Savannah, GA 31411 USA. RI Truhlar, Donald/G-7076-2015 OI Truhlar, Donald/0000-0002-7742-7294 NR 7 TC 21 Z9 21 U1 0 U2 9 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 NOV 17 PY 2000 VL 330 IS 5-6 BP 629 EP 632 DI 10.1016/S0009-2614(00)01140-4 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 378PJ UT WOS:000165592500021 ER PT J AU Tran, NL Colvin, ME AF Tran, NL Colvin, ME TI The prediction of biochemical acid dissociation constants using first principles quantum chemical simulations SO JOURNAL OF MOLECULAR STRUCTURE-THEOCHEM LA English DT Article DE quantum chemistry; pK(a); acid constants; DNA bases ID DENSITY-FUNCTIONAL THEORY; FREE-ENERGIES; SOLVATION MODELS; AQUEOUS-SOLUTION; AB-INITIO; VIBRATIONAL FREQUENCIES; IONIZATION-POTENTIALS; BORN MODEL; SOLVENT; PROTONATION AB Proton transfer is a vital part of many chemical processes and is determined by the acid dissociation constants (pK(a)) of the chemicals involved. The goal of this study is to evaluate existing quantum chemical methods to accurately predict pK(a) and to determine the trade-off between accuracy and computational cost. We used density functional theory (DFT) with the B3LYP functional and two basis sets, 6-31G** and 6-31++G(3df,3pd). To include the effects of aqueous solvation, we used DFT combined with a polarizable continuum solvation model as well as the Langevin dipole model. Using largest basis set and aqueous-phase optimized structures, we find a strong linear relationship between the predicted and calculated pK(a)'s R-2 = 0.94 and even stronger fits within the individual classes of compounds. Despite these strong linear correlations, we find a systematic error leading to a much larger range in the predicted pK(a) values. We studied the effect of excluding the enthalpy and entropy terms, using the gas-phase optimized structures, and using a smaller basis set, and found in all cases no significant decrease in the accuracy of the predicted pK(a) values. We also calculated the pK(a) values from the gas-phase energies, excluding any solvation effects, and also found a strong linear relation with the experimental pK(a) values, although with much larger systematic errors in the range of predicted pK(a) values. Finally, we found that the Langevin dipole method yielded pK(a) values with smaller absolute errors than the PCM methods, bur yielded poorer linear fits to the experimental values. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Computat Biol Grp, Biol & Biotechnol Res Program, Dept Comp Sci, Livermore, CA 94550 USA. RP Colvin, ME (reprint author), Univ Calif Lawrence Livermore Natl Lab, Computat Biol Grp, Biol & Biotechnol Res Program, Dept Comp Sci, Mailstop L-448, Livermore, CA 94550 USA. NR 39 TC 19 Z9 20 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0166-1280 J9 J MOL STRUC-THEOCHEM JI Theochem-J. Mol. Struct. PD NOV 17 PY 2000 VL 532 BP 127 EP 137 DI 10.1016/S0166-1280(00)00509-1 PG 11 WC Chemistry, Physical SC Chemistry GA 369JV UT WOS:000165062900015 ER PT J AU Du, LM Holzman, SL Mohandas, N Trost, BA Scott, JP Hillery, CA AF Du, LM Holzman, SL Mohandas, N Trost, BA Scott, JP Hillery, CA TI Increased fibrin deposition at sites of vaso-occlusion in transgenic sickle mice. SO BLOOD LA English DT Meeting Abstract C1 Med Coll Wisconsin, Milwaukee, WI 53226 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Blood Ctr SE Wisconsin Inc, Blood Res Inst, Milwaukee, WI 53233 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC HEMATOLOGY PI WASHINGTON PA 1900 M STREET. NW SUITE 200, WASHINGTON, DC 20036 USA SN 0006-4971 J9 BLOOD JI Blood PD NOV 16 PY 2000 VL 96 IS 11 MA 3721 BP 16B EP 16B PN 2 PG 1 WC Hematology SC Hematology GA 372WC UT WOS:000165256200061 ER PT J AU Toh, CH Downey, C Wenstone, R Paton, R Ticknor, L AF Toh, CH Downey, C Wenstone, R Paton, R Ticknor, L TI The value of the APTT waveform in predicting mortality and haemostatic dysfunction. SO BLOOD LA English DT Meeting Abstract C1 Univ Liverpool, Liverpool L69 3BX, Merseyside, England. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC HEMATOLOGY PI WASHINGTON PA 1900 M STREET. NW SUITE 200, WASHINGTON, DC 20036 USA SN 0006-4971 J9 BLOOD JI Blood PD NOV 16 PY 2000 VL 96 IS 11 MA 210 BP 51A EP 51A PN 1 PG 1 WC Hematology SC Hematology GA 372WB UT WOS:000165256100211 ER PT J AU Boultwood, J Fidler, C Strickson, AJ Watkins, F Jaju, RJ Kasprzyk, A Cheng, JF Wainscoat, JS AF Boultwood, J Fidler, C Strickson, AJ Watkins, F Jaju, RJ Kasprzyk, A Cheng, JF Wainscoat, JS TI Narrowing and genomic annotation of the critical region of the 5q-syndrome. SO BLOOD LA English DT Meeting Abstract C1 Univ Oxford, LRF Mol Haematol Unit, Oxford, England. EMBL European Bioinformat Inst, Cambridge, England. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC HEMATOLOGY PI WASHINGTON PA 1900 M STREET. NW SUITE 200, WASHINGTON, DC 20036 USA SN 0006-4971 J9 BLOOD JI Blood PD NOV 16 PY 2000 VL 96 IS 11 MA 1525 BP 353A EP 353A PN 1 PG 1 WC Hematology SC Hematology GA 372WB UT WOS:000165256101526 ER PT J AU Hou, VC Gee, SL Wu, M Turck, CW Mayeda, A Conboy, JG AF Hou, VC Gee, SL Wu, M Turck, CW Mayeda, A Conboy, JG TI Developmentally-regulated expression of hnRNP A1 can regulate alternative splicing of protein 4.1R exon 16 through an interaction with an exonic splicing silencer. SO BLOOD LA English DT Meeting Abstract C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Univ Calif San Francisco, Cardiovasc Res Inst, Dept Med, San Francisco, CA 94143 USA. Univ Miami, Sch Med, Miami, FL USA. Univ Calif Berkeley, Berkeley, CA 94720 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER SOC HEMATOLOGY PI WASHINGTON PA 1900 M STREET. NW SUITE 200, WASHINGTON, DC 20036 USA SN 0006-4971 J9 BLOOD JI Blood PD NOV 16 PY 2000 VL 96 IS 11 MA 1897 BP 441A EP 441A PN 1 PG 1 WC Hematology SC Hematology GA 372WB UT WOS:000165256101898 ER PT J AU Spring, F Parsons, S Lee, G Brady, L Mohandas, N Anstee, D Chasis, J AF Spring, F Parsons, S Lee, G Brady, L Mohandas, N Anstee, D Chasis, J TI Mouse homologue of erythrocyte adhesion molecule LW is a counterreceptor for both beta 1 and alpha V integrins. SO BLOOD LA English DT Meeting Abstract C1 Bristol Inst Transfus Sci, Bristol, Avon, England. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Bristol, Bristol, Avon, England. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC HEMATOLOGY PI WASHINGTON PA 1900 M STREET. NW SUITE 200, WASHINGTON, DC 20036 USA SN 0006-4971 J9 BLOOD JI Blood PD NOV 16 PY 2000 VL 96 IS 11 MA 1899 BP 441A EP 441A PN 1 PG 1 WC Hematology SC Hematology GA 372WB UT WOS:000165256101900 ER PT J AU Hunger, SP Boomer, T McGavran, L Meltesen, L Olsen, AS Varella-Garcia, M AF Hunger, SP Boomer, T McGavran, L Meltesen, L Olsen, AS Varella-Garcia, M TI FISH detection of E2A translocations in leukemia. SO BLOOD LA English DT Meeting Abstract C1 Univ Colorado, Hlth Sci Ctr, Dept Pediat, Denver, CO 80262 USA. Univ Colorado, Hlth Sci Ctr, Dept Med, Denver, CO 80262 USA. Univ Colorado, Hlth Sci Ctr, Dept Pathol, Denver, CO 80262 USA. Lawrence Livermoe Natl Lab, Biol & Biotechnol Res Program, Livermore, CA USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC HEMATOLOGY PI WASHINGTON PA 1900 M STREET. NW SUITE 200, WASHINGTON, DC 20036 USA SN 0006-4971 J9 BLOOD JI Blood PD NOV 16 PY 2000 VL 96 IS 11 MA 1994 BP 463A EP 463A PN 1 PG 1 WC Hematology SC Hematology GA 372WB UT WOS:000165256101995 ER PT J AU Holzman, SL Hui, S Du, LM Mohandas, N Scott, JP Hudetz, AG Hillery, CA AF Holzman, SL Hui, S Du, LM Mohandas, N Scott, JP Hudetz, AG Hillery, CA TI Inhibition of nitric oxide synthase induces acute vaso-occlusion in transgenic sickle mice. SO BLOOD LA English DT Meeting Abstract C1 Med Coll Wisconsin, Milwaukee, WI 53226 USA. Blood Ctr SE Wisconsin Inc, Blood Res Inst, Milwaukee, WI 53233 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER SOC HEMATOLOGY PI WASHINGTON PA 1900 M STREET. NW SUITE 200, WASHINGTON, DC 20036 USA SN 0006-4971 J9 BLOOD JI Blood PD NOV 16 PY 2000 VL 96 IS 11 MA 2271 BP 528A EP 528A PN 1 PG 1 WC Hematology SC Hematology GA 372WB UT WOS:000165256102271 ER PT J AU Turhan, A Weiss, LA Mohandas, N Coller, BS Frenette, PS AF Turhan, A Weiss, LA Mohandas, N Coller, BS Frenette, PS TI Sickle cell interactions with adherent leukocytes can initiate venular occlusion in sickle cell mice. SO BLOOD LA English DT Meeting Abstract C1 CUNY Mt Sinai Sch Med, Dept Med, New York, NY 10029 USA. Lawrence Berkeley Lab, Berkeley, CA USA. RI Frenette, Paul/J-8272-2012; Turhan, Aslihan/G-2963-2013; Weiss, Linnea/K-8062-2014 NR 0 TC 2 Z9 2 U1 0 U2 1 PU AMER SOC HEMATOLOGY PI WASHINGTON PA 1900 M STREET. NW SUITE 200, WASHINGTON, DC 20036 USA SN 0006-4971 J9 BLOOD JI Blood PD NOV 16 PY 2000 VL 96 IS 11 MA 2268 BP 528A EP 528A PN 1 PG 1 WC Hematology SC Hematology GA 372WB UT WOS:000165256102268 ER PT J AU Parra, MK Cheng, JF Chan, N Weier, HUG Mohandas, N Conboy, JG AF Parra, MK Cheng, JF Chan, N Weier, HUG Mohandas, N Conboy, JG TI Gene structure in the protein 4.1 family: Evidence for domains of conservation and regions of evolutionary divergence. SO BLOOD LA English DT Meeting Abstract C1 Lawrence Berkeley Natl Lab, Div Life Sci, Berkeley, CA USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC HEMATOLOGY PI WASHINGTON PA 1900 M STREET. NW SUITE 200, WASHINGTON, DC 20036 USA SN 0006-4971 J9 BLOOD JI Blood PD NOV 16 PY 2000 VL 96 IS 11 MA 2541 BP 592A EP 592A PN 1 PG 1 WC Hematology SC Hematology GA 372WB UT WOS:000165256102541 ER PT J AU Noguchi, CT Gladwin, M Diwan, B Jafri, J Buzard, G Fitzhugh, A Keefer, L Schechter, AN Mohandas, N AF Noguchi, CT Gladwin, M Diwan, B Jafri, J Buzard, G Fitzhugh, A Keefer, L Schechter, AN Mohandas, N TI Developing a useful model for sickle cell disease: Hemizygotes for the mouse beta-globin gene. SO BLOOD LA English DT Meeting Abstract C1 NIDDK, Biol Chem Lab, NIH, Bethesda, MD USA. NIH, Ctr Clin, Dept Crit Care Med, Bethesda, MD 20892 USA. NCI, Frederick Canc Res & Dev Ctr, SAIC Frederik, Frederick, MD USA. NCI, Frederick Canc Res & Dev Ctr, LCC, Frederick, MD USA. Lawrence Berkeley Natl Lab, Div Life Sci, Berkeley, CA USA. NR 0 TC 1 Z9 1 U1 1 U2 1 PU AMER SOC HEMATOLOGY PI WASHINGTON PA 1900 M STREET. NW SUITE 200, WASHINGTON, DC 20036 USA SN 0006-4971 J9 BLOOD JI Blood PD NOV 16 PY 2000 VL 96 IS 11 MA 2568 BP 598A EP + PN 1 PG 2 WC Hematology SC Hematology GA 372WB UT WOS:000165256102568 ER PT J AU Shi, Z Chumbley, S Laabs, FC AF Shi, Z Chumbley, S Laabs, FC TI Electron diffraction analysis of an AB(2)-type Laves phase for hydrogen battery applications SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article DE transmission electron microscopy; electron diffraction; Laves phases; hydrogen storage; battery alloys ID METAL HYDRIDE ELECTRODES; CRYSTAL-STRUCTURE; ALLOYS; TI; STABILITY; MN AB A multicomponent AB(2) type nickel-metal hydride (Ni-MH) battery alloy prepared by high-pressure gas atomization (HPGA) was investigated by transmission electron microscopy (TEM) in both the as-atomized and heat treated condition. TEM examination showed a heavily faulted dendritic growth structure in as-atomized powder. Selected area diffraction (SAD) showed that this region consisted of both a cubic C15 structure with lattice constant a = 7.03 Angstrom and an hexagonal C14 structure with lattice parameter a = 4.97 Angstrom, c = 8.11 Angstrom. The orientation relationship (OR) between the C14 and C15 structures was determined to be (111)[1 (1) over bar0](C15)//(0001)[11 (2) over bar0]C-14. An interdendritic phase possessing the C14 structure was also seen. There was also a very fine grain region consisting of the C14 structure. Upon heat treatment, the faulted structure became more defined and appeared as intercalation layers within the grains. Spherical particles rich in Zr and Ni appeared scattered at the grain boundries instead of the C14 interdendritic phase. The polycrystalline region also changed to a mixture of C14 and C15 structures. The phase stability of the C15 and C14 structures based on a consideration of atomic size factor and the average electron concentration is discussed. (C) 2000 Elsevier Science BN. All rights reserved. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Chumbley, S (reprint author), Iowa State Univ, Ames Lab, 214 Wilhelm, Ames, IA 50011 USA. EM chumbley@iastate.edu NR 25 TC 22 Z9 22 U1 2 U2 5 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 EI 1873-4669 J9 J ALLOY COMPD JI J. Alloy. Compd. PD NOV 16 PY 2000 VL 312 IS 1-2 BP 41 EP 52 DI 10.1016/S0925-8388(00)01078-1 PG 12 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 376LJ UT WOS:000165458800008 ER PT J AU Schlagel, DL Wu, YL Zhang, W Lograsso, TA AF Schlagel, DL Wu, YL Zhang, W Lograsso, TA TI Chemical segregation during bulk single crystal preparation of Ni-Mn-Ga ferromagnetic shape memory alloys SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article DE magnetostriction; ferromagnetic shape memory alloy; Ni-Mn-Ga; single crystal; Heusler alloy ID SYSTEM; PHASE AB Preparation of bulk single crystals of the ferromagnetic shape memory alloy Ni2MnGa has been accomplished using the Bridgman method. Magnetic and magnetostrictive properties from samples sectioned from different portions of the crystal showed high variability, indicating significant chemical segregation occurred during single crystal growth. This chemical segregation during crystal growth implies that the compound Ni2MnGa does not melt congruently. Partial evaluation of the liquidus diagram of Ni-Mn-Ga by thermal analysis and microstructural evaluation has determined that the primary solidification surface for the Heusler alloy phase exists over a wide range of compositions. The primary solidification surface falls modestly in temperature with either increasing Mn or Ga concentration. The composition Ni50Mn25Ga25 melts incongruently over a temperature range of approximately 18 degreesC. Characterization of the compositional variation along the growth direction in the single crystals was done using energy dispersive spectrometry and the results normalized against the fraction solidified. Compositional changes during solidification followed constant electron/atom (e/a) ratios over most of the length of the ingot. Under the single crystal growth conditions, the segregation pattern corresponds to a fully mixed condition and the data was fitted to a complete mixing model. Partitioning coefficients for the elemental constituents and the overall compositions were determined. The partitioning coefficients were found to be uniformly consistent between different growth runs, even though the overall compositions differed between crystals. The martensite transition temperatures along the length of the crystal were measured by differential scanning calorimetry and compared to predicted transition temperatures based on the e/a concentration. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ, Ames Lab, Met & Ceram Program, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Dept Mat Sci & Engn, Ames, IA 50011 USA. RP Lograsso, TA (reprint author), Iowa State Univ, Ames Lab, Met & Ceram Program, 111A Met Dev, Ames, IA 50011 USA. NR 14 TC 96 Z9 98 U1 3 U2 14 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 NOV 16 PY 2000 VL 312 IS 1-2 BP 77 EP 85 DI 10.1016/S0925-8388(00)01161-0 PG 9 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 376LJ UT WOS:000165458800012 ER PT J AU Kim, YS AF Kim, YS TI V-O thermochemistry from the pure metal to the monoxide SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article DE V-O system; phase diagram; thermodynamics; oxygen isobars ID LIQUID-METALS; U-O; SYSTEMS; THERMODYNAMICS; SOLUBILITY AB Thermodynamic constraints together with Sieverts law were utilized to evaluate the partial thermodynamic functions of the V-O system from V to VO in the temperature range 800-1800 K. The p-C-T relationships for each phase region obtained in the literature were reassessed and new p-C-T relationships were proposed in the regions where data were scarce in the literature. The results are presented as the oxygen isobars superimposed on the phase diagram to characterize the system. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Engn, Idaho Falls, ID 83403 USA. RP Kim, YS (reprint author), Argonne Natl Lab, Div Engn, Idaho Falls, ID 83403 USA. NR 33 TC 3 Z9 3 U1 1 U2 3 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 NOV 16 PY 2000 VL 312 IS 1-2 BP 86 EP 93 DI 10.1016/S0925-8388(00)01152-X PG 8 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 376LJ UT WOS:000165458800013 ER PT J AU Kirchstetter, TW Novakov, T Morales, R Rosario, O AF Kirchstetter, TW Novakov, T Morales, R Rosario, O TI Differences in the volatility of organic aerosols in unpolluted tropical and polluted continental atmospheres SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CLOUD-CONDENSATION-NUCLEI; CARBONACEOUS AEROSOLS; PARTICULATE CONCENTRATIONS; UNITED-STATES; TROPOSPHERE; SULFATE; ALKANE; MATTER; ACE-2; COAST AB In this paper we describe experimental results that demonstrate that chemical and physical properties of the organic aerosol material in tropical trade winds an drastically different from the organic aerosol component typically found in fossil fuel combustion influenced atmospheres. These experiments were performed at a Caribbean location (Cape San Juan, Puerto Rico), and at a semiurban site influenced by common anthropogenic pollution (Berkeley, California). The results show that the volatility of the polluted and the (largely natural) tropical organic aerosols is vastly different. Specifically, we find that the tropical organic aerosol material is highly volatile. The condensed phase organic carbon (OC) appears to exist in equilibrium with its gas-phase counterpart. Its mass concentration drastically decreases if the concentration of the gas-phase is reduced. The condensed phase OC adjusts quickly to the new equilibrium when the equilibrium at the sampler inlet is perturbed. Consequently, the mass concentration of condensed phase OC in tropical aerosols may be governed by both natural and sampling induced changes in temperature and pressure that alter the gas-particle partitioning. As a result, analyses based on conventional filter techniques may result in OC mass concentrations that are not representative of actual ambient concentrations. In contrast, the anthropogenic aerosol OC is much more stable and not appreciably influenced by changes in gas-phase organic compound concentrations. C1 Univ Puerto Rico, Dept Chem, Rio Piedras, PR 00931 USA. RP Kirchstetter, TW (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Environm Technol Div, MS-73,1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 20 TC 11 Z9 11 U1 1 U2 4 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 NOV 16 PY 2000 VL 105 IS D21 BP 26547 EP 26554 DI 10.1029/2000JD900381 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 375VH UT WOS:000165421600015 ER PT J AU McGivern, WS Sorkhabi, O Suits, AG Derecskei-Kovacs, A North, SW AF McGivern, WS Sorkhabi, O Suits, AG Derecskei-Kovacs, A North, SW TI Primary and secondary processes in the photodissociation of CHBr3 SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID AB-INITIO; HIGH-RESOLUTION; DISSOCIATION; OZONE; BROMOMETHANES; SPECTROSCOPY; ATMOSPHERE; ABSORPTION; RADICALS; DYNAMICS AB The photodissociation of CHBr3 at 193 nm has been investigated using photofragment translational spectroscopy with VUV ionization detection. The only primary process observed was the loss of bromine atom. The translational energy distribution for this channel suggests a direct dissociation from an excited electronic state, and the anisotropy parameter, beta = 0.0, is consistent with a transition dipole moment aligned perpendicular to the C-3v axis. The majority of nascent CHBr2 fragments undergo secondary dissociation via two competing channels. The elimination of HBr and C-Br bond cleavage in CHBr2 occur with comparable yields. We also provide ab initio calculations on the relevant photochemical species and RRKM estimates of the product branching ratios that are consistent with the experimental observations. C1 Texas A&M Univ, Dept Chem, College Stn, TX 77842 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP North, SW (reprint author), Texas A&M Univ, Dept Chem, College Stn, TX 77842 USA. RI North, Simon/G-5054-2012 OI North, Simon/0000-0002-0795-796X NR 34 TC 53 Z9 54 U1 1 U2 8 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 NOV 16 PY 2000 VL 104 IS 45 BP 10085 EP 10091 DI 10.1021/jp0005017 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 374QG UT WOS:000165355400004 ER PT J AU Choi, H Bise, RT Neumark, DM AF Choi, H Bise, RT Neumark, DM TI Photodissociation dynamics of the ethoxy radical (C2H5O) SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID LASER-INDUCED FLUORESCENCE; RATE CONSTANTS; OH RADICALS; AB-INITIO; PHOTOELECTRON-SPECTROSCOPY; ABSORPTION-SPECTRUM; HYDROXYL RADICALS; REACTION PATHWAYS; UV SPECTRUM; DEGREES K AB Photodissociation of the ethoxy (C2H5O) radical is investigated using photofragment translational spectroscopy. The ethoxy radical is generated by photodetachment of C2H5O- and subsequently dissociated by photon absorption in the range of 270-220 nm; no dissociation is seen at higher wavelengths. The photofragment yield (PFY) spectrum is structureless but exhibits abrupt increases in intensity at 260 and 225 nm. The product mass distribution shows that C2H5O dissociates into the vinyl radical (C2H3) and H2O throughout the entire absorption band. We propose that these products are formed by isomerization and dissociation on electronically excited surfaces rather than by internal conversion to the ground state. The translational energy P(ET) distributions for this channel are largely insensitive to photon energy. However, at the two highest photon energies (5.51 and 5.96 eV), a new feature appears at E-T less than or equal to 0.3 eV, which is assigned as production of an excited state of C2H3. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Neumark, DM (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Neumark, Daniel/B-9551-2009 OI Neumark, Daniel/0000-0002-3762-9473 NR 50 TC 14 Z9 14 U1 1 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 NOV 16 PY 2000 VL 104 IS 45 BP 10112 EP 10118 DI 10.1021/jp0003050 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 374QG UT WOS:000165355400007 ER PT J AU Kobayashi, K Pride, LD Sears, TJ AF Kobayashi, K Pride, LD Sears, TJ TI Absorption spectroscopy of singlet CH2 near 9500 cm(-1) SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID DISPERSED FLUORESCENCE SPECTROSCOPY; MAGNETIC-ROTATION SPECTROSCOPY; ORBITAL ANGULAR-MOMENTUM; VIBRATIONAL RESONANCES; VISIBLE ABSORPTION; METHYLENE; SPECTRUM; STATE; TRANSITION; (CH2)-C-1 AB The (b) over tilde B-1(1)-(a) over tilde (1)A(1) spectrum of methylene between 9317 and 9610 cm(-1) was recorded using frequency-modulated diode laser absorption spectroscopy. This is the lowest-energy region ever observed in the CH2((b) over tilde B-1(1)) electronic state. Transitions to four upper rovibronic levels were identified using known ground-state combination differences. On the basis of comparison with published results of ab initio calculations, they were assigned to levels with both (a) over tilde and (b) over tilde primary electronic wave function character: K = 0 (b) over tilde (0,1,0), K = 4 (b) over tilde (0,0,0), K = 1 (a) over tilde (0,8,0), and K = 0 (b) over tilde (0,2,0). The first three of these levels had not previously been observed. The rotational assignments of the last, K = 0 (b) over tilde (0,2,0), observed via transitions from the (a) over tilde (0,1,0) vibrationally hot bending level, differ from the original assignments of Herzberg and Johns [Proc. R. Sec. London, Ser. A 1966, 295, 107]. A comparison with the results of the most recent high-level quantum chemical calculations suggests that further refinement of the potential energy surface of the b state near its equilibrium would be desirable. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Sears, TJ (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RI Sears, Trevor/B-5990-2013; OI Sears, Trevor/0000-0002-5559-0154; Kobayashi, Kaori/0000-0002-4163-9498 NR 36 TC 16 Z9 16 U1 0 U2 0 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 NOV 16 PY 2000 VL 104 IS 45 BP 10119 EP 10124 DI 10.1021/jp000293i PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 374QG UT WOS:000165355400008 ER PT J AU Williams, S Harding, LB Stanton, JF Weisshaar, JC AF Williams, S Harding, LB Stanton, JF Weisshaar, JC TI Barrier to methyl internal rotation of 1-methylvinoxy radical in the (X)over-tilde((2)A '') and (B)over-tilde((2)A '') states: Experiment and theory SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID LASER-INDUCED FLUORESCENCE; CONFIGURATION-INTERACTION CALCULATIONS; CORRELATED MOLECULAR CALCULATIONS; COUPLED-CLUSTER METHOD; AB-INITIO CALCULATIONS; GAUSSIAN-BASIS SETS; EXCITED-STATES; WAVE-FUNCTIONS; ATOMS; SPECTROSCOPY AB The jet-cooled laser induced fluorescence spectrum of the (B) over tilde <-- <(X)over tilde> electronic transition of the 1-methylvinoxy radical is assigned, including both hot and cold bands. The barrier to methyl internal rotation in both (X) over tilde and (B) over tilde states is determined by fitting pure torsional transitions to a one-dimensional hindered-rotor model. The resulting 3-fold torsional barrier parameters are V-3' = -740 +/- 30 cm(-1) for the (B) over tilde state (minimum-energy conformation with one methyl CH bond cis to the frame CO bond) and V-3" = +130 +/- 30 cm(-1) for the (X) over tilde state (methyl CH bond trans to CO). The intensity pattern clearly indicates a change in the preferred methyl conformation upon excitation, while ab initio calculations provide the absolute conformations in each state, A variety of ab initio methods including CASSCF, multireference CI, and coupled-cluster techniques were applied to both the (X) over tilde and the (B) over tilde states of 1-methylvinoxy. Only the largest coupled-cluster calculations yield a (B) over tilde -state barrier in good quantitative agreement with experiment. In unsubstituted vinery, a (B) over tilde -state geometry adjusted earlier to fit experimental rotational constants (ref 10) is evidently in error. C1 Univ Wisconsin, Dept Chem, Madison, WI 53706 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Univ Texas, Dept Chem & Biochem, Inst Theoret Chem, Austin, TX 78712 USA. RP Univ Wisconsin, Dept Chem, 1101 Univ Ave, Madison, WI 53706 USA. EM weisshaar@chem.wisc.edu NR 47 TC 16 Z9 16 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD NOV 16 PY 2000 VL 104 IS 45 BP 10131 EP 10138 DI 10.1021/jp001009q PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 374QG UT WOS:000165355400010 ER PT J AU Macdonald, RG AF Macdonald, RG TI Rotational and vibrational state distributions of HNC(0 v(2)(1) 0) from the hot H atom reaction: H+(CN)(2)-> HNC+CN SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID REACTION DYNAMICS; INFRARED CHEMILUMINESCENCE; ENERGY-DISTRIBUTION; REACTION PRODUCTS; TRANSITION-STATE; 193 NM; DISSOCIATION; SPECTROSCOPY; PHOTOLYSIS; REGION AB The reaction dynamics of the five-atom system, H + (CN)(2), was investigated by probing the minor product channel producing the transient HNC molecule. The complete initial energy disposition, translation, rotation, and vibration was determined for the HNC(0 v(2)(1) 0), v(2)(1)= 0(0), 1(1), product. The reaction was studied under bulk conditions and was initiated by energetic H atoms with a mean translational energy of 92 kJ mol(-1). The HNC molecule was monitored by time- and frequency-resolved absorption spectroscopy with sub-Doppler resolution. The initial rotational state distribution of each HNC(0 v(2)(1) 0) vibrational level was measured and found to be well-described by a Boltzmann distribution. Only two vibrational levels were detected so that the initial HNC product vibrational level distribution was determined as well. The absolute reaction cross section for the title reaction was measured to be 2 x 10(-18) cm(2) for H atoms with a nominal translational energy of 113 kJ mol.(-1) 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 43 TC 2 Z9 2 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 NOV 16 PY 2000 VL 104 IS 45 BP 10202 EP 10211 DI 10.1021/jp0010583 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 374QG UT WOS:000165355400019 ER PT J AU Costen, ML Katayanagi, H Hall, GE AF Costen, ML Katayanagi, H Hall, GE TI State correlations in the unimolecular dissociation of ketene SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID PHASE-SPACE THEORY; INFRARED-SPECTROSCOPY; DOPPLER SPECTROSCOPY; VECTOR CORRELATIONS; TRANSITION-STATES; BRANCHING RATIO; SINGLET KETENE; BOND-BREAKING; AB-INITIO; 308 NM AB Doppler-broadened absorption spectra of selected rotational levels of singlet CH2 fragments from the 308-nm photolysis of ketene have been observed by frequency-modulated transient absorption spectroscopy in a slit jet expansion. Nascent Doppler profiles of CH2 transitions have been analyzed to yield the internal energy distributions of coincident CO fragments at a total energy 2333 cm(-1) above the singlet dissociation threshold. The vibrational branching ratio of CO (v = 1):(v = 0) is determined in coincidence with selected rotational levels of CH2. The coincident rotational distributions of CO (v = 0) are also estimated and found to differ from simple statistical predictions, revealing a relative deficiency of those pairs in which both fragments have a low internal energy. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Inst Mol Sci, Okazaki, Aichi 4448585, Japan. RP Hall, GE (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RI Katayanagi, Hideki/J-3518-2016; Hall, Gregory/D-4883-2013; Costen, Matthew/K-5178-2012 OI Katayanagi, Hideki/0000-0003-3647-4331; Hall, Gregory/0000-0002-8534-9783; Costen, Matthew/0000-0002-6491-9812 NR 50 TC 18 Z9 20 U1 0 U2 0 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 NOV 16 PY 2000 VL 104 IS 45 BP 10247 EP 10258 DI 10.1021/jp001389f PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 374QG UT WOS:000165355400025 ER PT J AU Lakshmi, KV Reifler, MJ Brudvig, GW Poluektov, OG Wagner, AM Thurnauer, MC AF Lakshmi, KV Reifler, MJ Brudvig, GW Poluektov, OG Wagner, AM Thurnauer, MC TI High-field EPR study of carotenoid and chlorophyll cation radicals in photosystem II SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Letter AB In photosystem II (PS II), chlorophyll, p-carotene, and cytochrome b(559) an alternate electron donors that may be involved in a photoprotection mechanism. The present study describes the use of high-field EPR spectroscopy to characterize the low-temperature photooxidation of Chit and Car cofactors in PS II. The EPR signals of the individual species, previously not resolved at X-band frequency (9 GHz), are resolved at higher D-band frequency (130 GHz) in deuterated Synechococcus lividus PS II. Deuteration of PS II results in significant narrowing of the EPR lines, yielding well-resolved EPR spectra of the Car(+) and Chl(Z)(+) radicals at 130 GHz. The g tensors of the individual species were determined by EPR spectral simulations. The g tensor determined for the Car(+) radical (g(xx) = 2.00335, g(yy) = 2.00251, g(zz) = 2.00227) is similar to that previously observed for a canthaxanthin cation radical but with a slightly rhombic tensor. The Chl(Z)(+) g tensor (g(xx) = 2.00312, g(yy) = 2.00263, g(zz) = 2.00202) is similar to that of a chlorophyll a cation radical. This study shows that both the carotenoid and chlorophyll radicals are generated in PS II by illumination at temperatures from 6 to 190 K and that there is no interconversion of Car(+) and Chl(Z)(+) radicals upon dark annealing at temperatures up to 160 K. This study also establishes the feasibility of using deuteration and high-field EPR to resolve previously unresolvable cofactor signals in PS II. C1 Yale Univ, Dept Chem, New Haven, CT 06520 USA. Argonne Natl Lab, Dept Chem, Argonne, IL 60439 USA. RP Thurnauer, MC (reprint author), Yale Univ, Dept Chem, POB 208107, New Haven, CT 06520 USA. RI Lakshmi, K. V./A-9787-2017 OI Lakshmi, K. V./0000-0001-5443-9017 NR 25 TC 39 Z9 42 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 NOV 16 PY 2000 VL 104 IS 45 BP 10445 EP 10448 DI 10.1021/jp002558z PG 4 WC Chemistry, Physical SC Chemistry GA 374QL UT WOS:000165355800001 ER PT J AU Gibbs, GV Boisen, MB Rosso, KM Teter, DM Bukowinski, MST AF Gibbs, GV Boisen, MB Rosso, KM Teter, DM Bukowinski, MST TI Model structures and electron density distributions for the silica polymorph coesite at pressure: An assessment of OO bonded interactions SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID CRITICAL-POINT PROPERTIES; X-RAY; DIFFRACTION; CHEMISTRY; CRYSTALS; QUARTZ; MGO; SIO AB The crystal structure and the bond critical point, bcp, properties of the electron density distribution for the high-pressure silica polymorph coesite were generated for pressures up to similar to 17 GPa, using first-principles calculations. The nonequivalent SiO bond lengths and the SiOSi and OSiO angles of the generated structures agree with those observed to within similar to1%. With compression, the SiO bond lengths and the variable SiOSi angles of the structures both decrease while the value of the electron density, p(r(c)), the curvatures, and the Laplacian of the electron density distribution at the bond critical points each increases slightly. As found in a recent modeling of the structure of low quartz, the calculated electron density distributions are nearly static and change relatively little with compression. The bcp properties of the model structure agree with those observed at ambient conditions to within similar to 10%, on average, with several of the properties observed to correlate with the observed SiO bond lengths, R(SIO). This agreement is comparable with that observed for several other silicates. As predicted, the bonded radius of the oxide anion, the curvatures of p(r(c)) paralleling the bond paths and the Laplacian of p(r(c)) each correlates with the observed bond lengths. However, the observed p(r(c)) values and the curvatures of p(r(c)) perpendicular to the paths fail to show a correlation with the observed bond lengths. The ellipticity of the SiO bonds in both the model and the observed structures tends to decrease in value as the SiOSi angle approaches 180 degrees, indicating that the bonds become more circular in cross sections as the angle widens. Ridges of electron density and bond critical points were found between the intertetrahedral oxide anions at each pressure. The existence of these features appears to be closely related to purely geometrical factors of the coesite structure rather than to bonded interactions. None of these features was found between the intratetrahedral oxide anions. C1 Virginia Tech, Dept Math, Blacksburg, VA 24061 USA. Virginia Tech, Dept Geol Sci, Blacksburg, VA 24061 USA. Virginia Tech, Dept Mat Sci & Engn, Blacksburg, VA 24061 USA. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Sandia Natl Labs, Dept Geochem, Albuquerque, NM 87185 USA. Univ Calif Berkeley, Dept Geol & Geophys, Berkeley, CA 94720 USA. RP Boisen, MB (reprint author), Virginia Tech, Dept Math, Blacksburg, VA 24061 USA. NR 29 TC 35 Z9 35 U1 0 U2 11 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 NOV 16 PY 2000 VL 104 IS 45 BP 10534 EP 10542 DI 10.1021/jp002113a PG 9 WC Chemistry, Physical SC Chemistry GA 374QL UT WOS:000165355800014 ER PT J AU Nakamura, T Aumann, T Bazin, D Blumenfeld, Y Brown, BA Caggiano, J Clement, R Glasmacher, T Lofy, PA Navin, A Pritychenko, BV Sherrill, BM Yurkon, J AF Nakamura, T Aumann, T Bazin, D Blumenfeld, Y Brown, BA Caggiano, J Clement, R Glasmacher, T Lofy, PA Navin, A Pritychenko, BV Sherrill, BM Yurkon, J TI Structure of the weakly-bound nucleus He-6 studied via the Li-6(t,He-3)He-6 reaction SO PHYSICS LETTERS B LA English DT Article DE halo/skin nucleus; charge exchange reaction ID CHARGE-EXCHANGE REACTIONS; COULOMB DISSOCIATION; PARITY STATES; LIGHT-NUCLEI; LI-11; EXCITATION; BE-11 AB The Li-6(t, He-3)He-6 charge-exchange reaction leading to the weakly-bound nucleus He-6 has been studied at 336 MeV. Beyond the strong peaks for the known ground state (J(pi) = 0(+)) and first excited state (J(pi) = 2(+), E-x = 1.8 MeV), a broad asymmetric structure around E-x similar to 5 MeV has been observed. The angular distribution of this structure exhibits the dominance of a DeltaL = 1 transition, indicating the existence of intruder states at low excitation energies in He-6. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Michigan State Univ, Natl Superconducting Cyclotron Lab, E Lansing, MI 48824 USA. Tokyo Inst Technol, Dept Phys, Meguro Ku, Tokyo 1528551, Japan. Inst Phys Nucl, IN2P3, CNRS, F-91406 Orsay, France. Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Michigan State Univ, Dept Chem, E Lansing, MI 48824 USA. Bhabha Atom Res Ctr, Div Nucl Phys, Bombay 400085, Maharashtra, India. RP Nakamura, T (reprint author), Michigan State Univ, Natl Superconducting Cyclotron Lab, E Lansing, MI 48824 USA. RI Glasmacher, Thomas/C-4462-2008; Sherrill, Bradley/B-4098-2009; Sherrill, Bradley/B-3378-2011; Aumann, Thomas/B-1455-2012; Glasmacher, Thomas/H-9673-2014; Nakamura, Takashi/N-5390-2015 OI Glasmacher, Thomas/0000-0001-9436-2448; Nakamura, Takashi/0000-0002-1838-9363 NR 37 TC 30 Z9 31 U1 0 U2 4 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 NOV 16 PY 2000 VL 493 IS 3-4 BP 209 EP 215 DI 10.1016/S0370-2693(00)01146-1 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 377YW UT WOS:000165554800001 ER PT J AU Radyushkin, AV Weiss, C AF Radyushkin, AV Weiss, C TI DVCS amplitude with kinematical twist-3 terms SO PHYSICS LETTERS B LA English DT Article ID PARTON DISTRIBUTIONS; EVOLUTION-EQUATIONS; OPERATORS; QCD; ELECTROPRODUCTION; NUCLEON AB We compute the amplitude of deeply virtual Compton scattering (DVCS) using the calculus of QCD string operators in coordinate representation. To restore the electromagnetic gauge invariance (transversality) of the twist-2 amplitude we include the operators of twist-3 which appear as total derivatives of twist-2 operators. Our results are equivalent to a Wandzura-Wilczek approximation for twist-3 skewed parton distributions. We find that, for the tensor amplitude T-mu nu, this approximation gives a finite result for the longitudinal polarization of the virtual photon and a divergent result in case of transverse polarization. However, the divergent part has zero projection onto the polarization vector of the final real photon. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Old Dominion Univ, Dept Phys, Norfolk, VA 23529 USA. Jefferson Lab, Theory Grp, Newport News, VA 23606 USA. Ruhr Univ Bochum, Inst Theoret Phys 2, D-4630 Bochum, Germany. JINR, Theoret Phys Lab, Dubna, Russia. RP Old Dominion Univ, Dept Phys, Norfolk, VA 23529 USA. EM radyush@jlab.org; weiss@tp2.ruhr-uni-bochum.de NR 20 TC 36 Z9 36 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 NOV 16 PY 2000 VL 493 IS 3-4 BP 332 EP 340 DI 10.1016/S0370-2693(00)01155-2 PG 9 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 377YW UT WOS:000165554800014 ER PT J AU Warner, S Catterall, S AF Warner, S Catterall, S TI Phase diagram of four-dimensional dynamical triangulations with a boundary SO PHYSICS LETTERS B LA English DT Article ID 4D SIMPLICIAL GRAVITY; QUANTUM-GRAVITY AB We report on simulations of DT simplicial gravity for manifolds with the topology of the 4-disk. We find evidence for four phases in a two-dimensional parameter space. In two of these the boundary plays no dynamical role and the geometries are equivalent to those observed earlier for the sphere S-4. In another phase the boundary is maximal and the quantum geometry degenerates to a one-dimensional branched polymer. In contrast we provide evidence that the fourth phase is effectively three-dimensional. We find discontinuous phase transitions at all the phase boundaries. (C) 2000 Published by Elsevier Science B.V. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Syracuse Univ, Dept Phys, Syracuse, NY 13210 USA. RP Warner, S (reprint author), Univ Calif Los Alamos Natl Lab, T-8, Los Alamos, NM 87545 USA. RI Warner, Simeon/E-2423-2011; OI Warner, Simeon/0000-0002-7970-7855; Catterall, Simon/0000-0003-2735-2682 NR 10 TC 2 Z9 2 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 NOV 16 PY 2000 VL 493 IS 3-4 BP 389 EP 394 DI 10.1016/S0370-2693(00)01154-0 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 377YW UT WOS:000165554800022 ER PT J AU Su, YX Duan, YX Jin, Z AF Su, YX Duan, YX Jin, Z TI Development and evaluation of a glow discharge microwave-induced-plasma tandem source for time-of-flight mass spectrometry SO ANALYTICAL CHEMISTRY LA English DT Article ID OPTICAL-EMISSION SPECTROMETRY; CAVITY AB In this work, a new glow discharge, microwave-induced-plasma (GDMIP), tandem ion source was developed, characterized, and used in conjunction with time-of-flight mass spectrometry. This tandem source was designed to be-simple and compact. The GD and the MTP unit are independent and demountable, providing flexibility in tuning and, operating. The microwave plasma can be formed with very low power (a few watts) and overlapped with the glow discharge. The discharge current increased with the addition of microwave discharge when the GD was operated in constant-voltage mode, and the amplitude of-the current increase was found to be related to microwave power, discharge pressure, and sampling distance.:With the addition of microwave discharge, significant signal enhancement was achieved under a discharge pressure of 2.0 Torr and a discharge voltage of 500 V with: 2.0-mm sampling distance. Enhanced factors of analyte signals ranging from similar to1 to nearly 10 could be obtained with MIP boosting, while no significant change in noise level was observed. This new tandem source provides improved performance in direct solid sample analysis. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Duan, YX (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, CST-9,MS K484, Los Alamos, NM 87545 USA. NR 13 TC 7 Z9 8 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 NOV 15 PY 2000 VL 72 IS 22 BP 5600 EP 5605 DI 10.1021/ac000679p PG 6 WC Chemistry, Analytical SC Chemistry GA 374LN UT WOS:000165346800012 PM 11101237 ER PT J AU Cullum, BM Mobley, J Bogard, JS Moscovitch, M Phillips, GW Vo-Dinh, T AF Cullum, BM Mobley, J Bogard, JS Moscovitch, M Phillips, GW Vo-Dinh, T TI Three-dimensional optical random access memory materials for use as radiation dosimeters SO ANALYTICAL CHEMISTRY LA English DT Article ID 2-PHOTON MEMORY; DEVICES AB This article describes the development of the first three-dimensional optical random access memory (3D-ORAM) material and readout system for monitoring energetic neutrons. Two different photochromic dyes, 5'-chloro-6-nitro-1',3',3'-trimethylspiro-[2H-1-benzopyran-2,2'-indoline] (spirobenzopyran) and anthracene, have been investigated for use in these 3-D GRAM dosimeter materials. These dyes were immobilized in a poly(methyl methacrylate) support, and the resulting dosimeter materials were irradiated with neutrons from a Cf-252 source. Fluorescence measurements from the dosimeter show a dramatic decrease in the overall fluorescence intensity of the 3D-ORAM dosimeter exposed to the Cf-252, relative to a nonirradiated dosimeter. In addition, a two-photon excitation readout system has been developed for determining characteristics of the radiation that are necessary for estimating dose. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Georgetown Univ, Med Ctr, Washington, DC 20007 USA. USN, Res Lab, Washington, DC 20375 USA. RP Vo-Dinh, T (reprint author), Oak Ridge Natl Lab, POB 2008,Bethel Valley Rd MS-6101, Oak Ridge, TN 37831 USA. NR 13 TC 10 Z9 11 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD NOV 15 PY 2000 VL 72 IS 22 BP 5612 EP 5617 DI 10.1021/ac000638t PG 6 WC Chemistry, Analytical SC Chemistry GA 374LN UT WOS:000165346800014 PM 11101239 ER PT J AU Magowan, C Nunomura, W Waller, KL Yeung, J Liang, J Van Dort, H Low, PS Coppel, RL Mohandas, N AF Magowan, C Nunomura, W Waller, KL Yeung, J Liang, J Van Dort, H Low, PS Coppel, RL Mohandas, N TI Plasmodium falciparum histidine-rich protein 1 associates with the band 3 binding domain of ankyrin in the infected red cell membrane SO BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR BASIS OF DISEASE LA English DT Article DE Plasmodium falciparum malaria; ankyrin; erythrocyte cytoskeleton; knob-associated histidine-rich protein; KAHRP; PfHRP1; phosphorylation; protein-protein interaction ID ERYTHROCYTE SURFACE-ANTIGEN; ANION-EXCHANGER; BLOOD-CELLS; SKELETAL PROTEIN; PHOSPHORYLATION; SPECTRIN; KNOBS; MALARIA; CYTOADHERENCE; PARASITE AB Infection of erythrocytes by the malaria parasite Plasmodium falciparum results in the export of several parasite proteins into the erythrocyte cytoplasm. Changes occur in the infected erythrocyte due to altered phosphorylation of proteins and to novel interactions between host and parasite proteins, particularly at the membrane skeleton. In erythrocytes, the spectrin based red cell membrane skeleton is linked to the erythrocyte plasma membrane through interactions of ankyrin with spectrin and band 3. Here we report an association between the P. falciparum histidine-rich protein (PfHRP1) and phosphorylated proteolytic fragments of red cell ankyrin. Immunochemical, biochemical and biophysical studies indicate that the 89 kDa band 3 binding domain and the 62 kDa spectrin-binding domain of ankyrin are co-precipitated by mAb 89 against PfHRP1, and that native and recombinant ankyrin fragments bind to the 5' repeat region of PfHRP1. PfHRP1 is responsible for anchoring the parasite cytoadherence ligand to the erythrocyte membrane skeleton, and this additional interaction with ankyrin would strengthen the ability of PfEMP1 to resist shear stress. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Tokyo Womens Med Univ, Dept Biochem, Tokyo 1628666, Japan. Purdue Univ, Dept Chem, W Lafayette, IN 47907 USA. Monash Univ, Dept Microbiol, Clayton, Vic 3168, Australia. RP Mohandas, N (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, 1 Cyclotron Rd,MS 157, Berkeley, CA 94720 USA. RI Coppel, Ross/A-6626-2008; OI Coppel, Ross/0000-0002-4476-9124; Low, Philip/0000-0001-9042-5528 FU NIDDK NIH HHS [DK32094] NR 57 TC 44 Z9 46 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0925-4439 J9 BBA-MOL BASIS DIS JI Biochim. Biophys. Acta-Mol. Basis Dis. PD NOV 15 PY 2000 VL 1502 IS 3 BP 461 EP 470 DI 10.1016/S0925-4439(00)00069-7 PG 10 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 374RL UT WOS:000165358100014 PM 11068188 ER PT J AU Makarova, OV Rajh, T Thurnauer, MC Martin, A Kemme, PA Cropek, D AF Makarova, OV Rajh, T Thurnauer, MC Martin, A Kemme, PA Cropek, D TI Surface modification of TiO2 nanoparticles for photochemical reduction of nitrobenzene SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID PHOTOCATALYTIC DEGRADATION; ORGANIC-COMPOUNDS; TITANIUM-DIOXIDE; COLLOIDAL TIO2; 2,4,6-TRINITROTOLUENE; TNT; MINERALIZATION; SLURRIES AB The effects of surface modification of nanocrystalline titanium dioxide (TiO2) with specific chelating agents on photocatalytic degradation of nitrobenzene (NB) was investigated in order to design a selective and effective catalyst for removal of nitroaromatic compounds from contaminated waste streams. Mechanisms of NE adsorption and photodecomposition were investigated using infrared absorption and electron paramagnetic resonance spectroscopy. Liquid chromatography and gas chromatography/mass spectrometry were used for byproduct analyses. Arginine, lauryl sulfate, and salicylic acid were found to bind to TiO2 via their oxygen-containing functional groups. Modification of the TiO2 surface with arginine resulted in enhanced NE adsorption and photodecomposition, and compared to unmodified TiO2. The initial quantum yield for photodegradation of NE in this system was found to be Phi (init) = 0.31 as compared to the one obtained for Degussa P25 of Phi (init) = 0.18. NE degradation followed a reductive pathway over arginine-modified TiO2 and was enhanced upon addition of methanol. No degradation of arginine was detected under the experimental conditions. Arginine improved the coupling between NE and TiO2 and facilitated the transfer of photogenerated electrons from the TiO2 conduction band to the adsorbed NE. These results indicate that surface modification of nanocrystalline TiO2 with electron-donating chelating agents is an effective route to enhance photodecomposition of nitroaromatic compounds. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. USA CERL, CN E, Champaign, IL 61826 USA. RP Makarova, OV (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 37 TC 121 Z9 126 U1 6 U2 64 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 NOV 15 PY 2000 VL 34 IS 22 BP 4797 EP 4803 DI 10.1021/es001109+ PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 373XT UT WOS:000165315900021 ER PT J AU Vulava, VM Seaman, JC AF Vulava, VM Seaman, JC TI Mobilization of lead from highly weathered porous material by extracting agents SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID MASS-SPECTROMETRY; ORGANIC-COMPOUNDS; TRANSPORT; FERRIHYDRITE; CYCLODEXTRIN; CONTAMINANTS; MIGRATION; MEDIA; SOIL; CHEMISTRY AB Batch and dynamic leaching experiments were conducted to evaluate the influence of clay mineralogy and soil organic matter (SOM) present in two highly weathered, surface and subsurface soil materials on Pb sorption and subsequent extraction using ethylenediaminetetraacetic acid (EDTA) and carboxymethyl beta -cyclodextrin (CMCD). Saturated soil columns were leached with an acidic Pb solution to simulate a contamination event, followed by injection of artificial groundwater (AGW) at constant velocity, Greater Pb retardation was observed within the surface soil compared to the subsurface soil material, and a significant increase in effluent turbidity was observed coincident with the Pb breakthrough in the subsurface soil material. Electrophoretic, thermo-gravimetric, and X-ray diffraction analysis of the resulting suspension suggested that the presence of strongly adsorbing Pb2+ and excess H+ increased the positive charge on amphoteric mineral surfaces and reduced the negative charge on clay minerals, which induced selective dispersion and transport of Fe oxides. In contrast, no increase in turbidity was observed for the surface soil following Pb injection. While only 30% of adsorbed Pb was mobilized from contaminated subsurface soil material, less than 10% of adsorbed Ph was extracted from surface soil when Pb-contaminated soil columns were flushed with AGW. Following leaching with AGW, extraction solutions containing either 0.37 g L-1 (1 mM) EDTA or 10 g L-1 CMCD were applied to extract the residual bound Pb. Nearly 100% of residual Ph was extracted from the surface soil by EDTA as compared to about 56% removal by CMCD under similar conditions. About 80% of residual Ph was removed by EDTA from the Pb-contaminated subsurface material, but less than 2% of residual Pb was extracted by CMCD under similar conditions. C1 Univ Georgia, Savannah River Ecol Lab, Adv Analyt Ctr Environm Sci, Aiken, SC 29802 USA. RP Vulava, VM (reprint author), Univ Georgia, Savannah River Ecol Lab, Adv Analyt Ctr Environm Sci, PO Drawer E, Aiken, SC 29802 USA. NR 46 TC 22 Z9 22 U1 1 U2 9 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 NOV 15 PY 2000 VL 34 IS 22 BP 4828 EP 4834 DI 10.1021/es001295j PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 373XT UT WOS:000165315900026 ER PT J AU Carrigan, CR Nitao, JJ AF Carrigan, CR Nitao, JJ TI Predictive and diagnostic simulation of in situ electrical heating in contaminated, low-permeability soils SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article AB By in situ heating, contaminants can be mobilized by vaporization, modified into a harmless chemical state, or entrapped by soil vitrification. However, effective heating may be difficult or impossible by depending solely upon conduction of heat externally applied to a contaminated target layer. Heating a layer internally by passing an electric current through it has been employed in several different in situ remediation field experiments. We present a three-dimensional computer model of groundwater flow and transport in an electrically heated, partially saturated, porous regime. Simulations are used to show that the uniformity of heating can be enhanced by increasing the number of electrical phases employed in supplying current to the electrodes. However, a more serious concern for the field-scale application of this internal heating method is the nonuniform heating of the target layer because of large heating-rate differences between the near-electrode region and the center of the array. finally, for a dissolved solvent like TCE, we show that ohmic heating is exceptionally effective at clearing the layer by vapor-phase partitioning. Once expelled from the low-permeability layer, the solvent that is not already thermally destroyed by a pyrolytic reaction is available for extraction. C1 Univ Calif Lawrence Livermore Natl Lab, Earth Sci Div L204, Livermore, CA 94550 USA. RP Carrigan, CR (reprint author), Univ Calif Lawrence Livermore Natl Lab, Earth Sci Div L204, Livermore, CA 94550 USA. NR 11 TC 16 Z9 17 U1 3 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 NOV 15 PY 2000 VL 34 IS 22 BP 4835 EP 4841 DI 10.1021/es001506k PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 373XT UT WOS:000165315900027 ER PT J AU Hsu, HL Gilley, D Galande, SA Hande, MP Allen, B Kim, SH Li, GC Campisi, J Kohwi-Shigematsu, T Chen, DJ AF Hsu, HL Gilley, D Galande, SA Hande, MP Allen, B Kim, SH Li, GC Campisi, J Kohwi-Shigematsu, T Chen, DJ TI Ku acts in a unique way at the mammalian telomere to prevent end joining SO GENES & DEVELOPMENT LA English DT Article DE telomere; TRF1; Ku ID DEPENDENT PROTEIN-KINASE; DNA-BINDING; POLY(ADP-RIBOSE) POLYMERASE; SACCHAROMYCES-CEREVISIAE; V(D)J RECOMBINATION; HUMAN-CELLS; LENGTH; MAINTENANCE; AUTOANTIGEN; HOMOLOG AB Telomeres are specialized DNA/protein structures that act as protective caps to prevent end fusion events and to distinguish the chromosome ends from double-strand breaks. We report that TRF1 and Ku form a complex at the telomere. The Ku and TRF1 complex is a specific high-affinity interaction, as demonstrated by several in vitro methods, and exists in human cells as determined by coimmunoprecipitation experiments. Ku does not bind telomeric DNA directly but localizes to telomeric repeats via its interaction with TRF1. Primary mouse embryonic fibroblasts that are deficient for Ku80 accumulated a large percentage of telomere fusions, establishing that Ku plays a critical role in telomere capping in mammalian cells. We propose that Ku localizes to internal regions of the telomere via a high-affinity interaction with TRF1. Therefore, Ku acts in a unique way at the telomere to prevent end joining. C1 Lawrence Berkeley Natl Lab, Dept Cell & Mol Biol, Div Life Sci, Berkeley, CA 94720 USA. Columbia Univ, Ctr Radiol Res, New York, NY 10032 USA. Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. Mem Sloan Kettering Canc Ctr, Dept Radiat Oncol, New York, NY 10021 USA. RP Chen, DJ (reprint author), Lawrence Berkeley Natl Lab, Dept Cell & Mol Biol, Div Life Sci, Berkeley, CA 94720 USA. RI Hande, M. Prakash/B-1645-2008; Hsu, Hsin-Ling/E-3672-2010 OI Hande, M. Prakash/0000-0002-4511-6256; FU NCI NIH HHS [CA39681, CA50519, R01 CA039681, R01 CA050519, R37 CA039681, R37 CA050519]; NIA NIH HHS [AG17709, R01 AG011658] NR 32 TC 245 Z9 255 U1 0 U2 2 PU COLD SPRING HARBOR LAB PRESS PI PLAINVIEW PA 1 BUNGTOWN RD, PLAINVIEW, NY 11724 USA SN 0890-9369 J9 GENE DEV JI Genes Dev. PD NOV 15 PY 2000 VL 14 IS 22 BP 2807 EP 2812 DI 10.1101/gad.844000 PG 6 WC Cell Biology; Developmental Biology; Genetics & Heredity SC Cell Biology; Developmental Biology; Genetics & Heredity GA 378BA UT WOS:000165560400002 PM 11090128 ER PT J AU Yushkov, GY Anders, A Oks, EM Brown, IG AF Yushkov, GY Anders, A Oks, EM Brown, IG TI Ion velocities in vacuum arc plasmas SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID CATHODE SPOT AB Ion velocities in vacuum arc plasmas have been measured for most conducting elements of the Periodic Table. The method is based on drift time measurements via the delay time between arc current modulation and ion flux modulation. A correlation has been found between the element-specific ion velocity and average ion charge state; however, differently charged ions of the same element have approximately the same velocity. These findings contradict the potential hump model but are in agreement with a gasdynamic model that describes ion acceleration as driven by pressure gradients and electron-ion friction. The differences between elements can be explained by the element-specific power density of the cathode spot plasma which in turn determines the temperature, average charge state, and ion velocity of the expanding vacuum arc plasma. (C) 2000 American Institute of Physics. [S0021-8979(00)08723-5]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Russian Acad Sci, Inst High Current Elect, Tomsk 634050, Russia. State Univ Control Syst & Radioelect, Tomsk 634050, Russia. RP Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. EM aanders@lbl.gov RI Oks, Efim/A-9409-2014; Anders, Andre/B-8580-2009; Yushkov, Georgy/O-8024-2015 OI Oks, Efim/0000-0002-9323-0686; Anders, Andre/0000-0002-5313-6505; Yushkov, Georgy/0000-0002-7615-6058 NR 29 TC 122 Z9 127 U1 2 U2 15 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 NOV 15 PY 2000 VL 88 IS 10 BP 5618 EP 5622 AR PII [S0021-8979(00)08723-5] DI 10.1063/1.1321789 PG 5 WC Physics, Applied SC Physics GA 369MA UT WOS:000165068700015 ER PT J AU Handy, EM Rao, MV Holland, OW Jones, KA Derenge, MA Papanicolaou, N AF Handy, EM Rao, MV Holland, OW Jones, KA Derenge, MA Papanicolaou, N TI Variable-dose (10(17)-10(20) cm(-3)) phosphorus ion implantation into 4H-SiC SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID BORON; JUNCTION; ALUMINUM; DONORS AB Multiple-energy box profile elevated-temperature (700 degreesC) phosphorus ion implantations were performed into 4H-SiC in the doping range of 1x10(17)-1x10(20) cm(-3). The implanted material was annealed at 1500, 1600, or 1650 degreesC with an AIN encapsulant to prevent degradation of the SiC surface. Within this temperature range the sheet resistance does not change significantly for a given dose. The percentage of electrical activation of the P donors initially decreased with increasing implant dose for P-implant concentration up to 3x10(19) cm(-3) and then increased again at higher doses. For 1x10(20) cm(-3) P implant, a carrier concentration of 4x10(19) cm(-3) was measured at room temperature. In the 10(17) cm(-3) P doping concentration range substitutional activation greater than 85% was measured. Despite performing the implants at 700 degreesC, a significant amount of as-implanted damage was observed in the Rutherford backscattering (RBS) spectrum, even for 10(18) cm(-3) range P implantations. The RBS yield after annealing is near the virgin level for P concentrations up to 1x10(19) cm(-3), but above this concentration the RBS yield is above the virgin level, indicating a significant amount of residual lattice damage in the crystal. (C) 2000 American Institute of Physics. [S0021-8979(00)00123-7]. C1 George Mason Univ, Dept Elect & Comp Engn, Fairfax, VA 22030 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. USA, Res Lab, SEDD, Adelphi, MD 20783 USA. USN, Res Lab, Washington, DC 20375 USA. RP Handy, EM (reprint author), George Mason Univ, Dept Elect & Comp Engn, Fairfax, VA 22030 USA. NR 27 TC 10 Z9 11 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD NOV 15 PY 2000 VL 88 IS 10 BP 5630 EP 5634 DI 10.1063/1.1319161 PG 5 WC Physics, Applied SC Physics GA 369MA UT WOS:000165068700017 ER PT J AU Ferguson, IT Norman, AG Seong, TY AF Ferguson, IT Norman, AG Seong, TY TI Relationship between the lateral length and thickness of the platelets in naturally occurring strained layer superlattice structures SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID MOLECULAR-BEAM EPITAXY; III-V-ALLOYS; SPINODAL DECOMPOSITION; GROWTH; SEGREGATION AB The molecular beam epitaxial growth of InAs0.5Sb0.5 onto (001) surfaces below 430 degreesC results in the formation of a "natural" strained layer superlattice (n-SLS). Transmission electron micrographs of [110] cross sections showed the existence of two different alloy compositions that formed a tetragonally distorted interleaved platelet structure in which the interfaces were highly regular and ran approximately parallel to the growing surface. It is found that the structure of the n-SLS can be changed systematically by carefully controlling the InAs0.5Sb0.5 growth conditions. A simple relationship is derived relating the lateral size of the platelet to its thickness that is found to hold experimentally for n-SLS structures. It is suggested that the n-SLS structure occurs because it corresponds to the minimum free energy configuration of the growing crystal. A similar formalization has been applied to periodic modulations in other material systems. (C) 2000 American Institute of Physics. [S0021-8979(00)08321-3]. C1 EMCORE Corp, Somerset, NJ 08873 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. Kwangju Inst Sci & Technol, Ctr Frontier Mat, Kwangju 506712, South Korea. RP Ferguson, IT (reprint author), EMCORE Corp, 394 Elizabeth Ave, Somerset, NJ 08873 USA. RI Norman, Andrew/F-1859-2010 OI Norman, Andrew/0000-0001-6368-521X NR 21 TC 2 Z9 2 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD NOV 15 PY 2000 VL 88 IS 10 BP 5733 EP 5736 DI 10.1063/1.1321676 PG 4 WC Physics, Applied SC Physics GA 369MA UT WOS:000165068700034 ER PT J AU Kim, Y Subramanya, SG Siegle, H Kruger, J Perlin, P Weber, ER Ruvimov, S Liliental-Weber, Z AF Kim, Y Subramanya, SG Siegle, H Kruger, J Perlin, P Weber, ER Ruvimov, S Liliental-Weber, Z TI GaN thin films by growth on Ga-rich GaN buffer layers SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID CHEMICAL-VAPOR-DEPOSITION; THREADING DISLOCATIONS; OPTICAL-PROPERTIES; GALLIUM NITRIDE; SAPPHIRE; STRESS; COEFFICIENT; EVOLUTION; SUBSTRATE; STRAIN AB The influence of the composition of the low-temperature GaN buffer layer on the structural, electrical, and optical properties of the subsequently grown GaN epilayer by molecular-beam epitaxy is investigated. It is found that decreasing the N/Ga flux ratio during the buffer layer growth yields excess Ga in the buffer layer. GaN epilayers grown on the buffer layer with excess Ga showed increased electron Hall mobility and reduced threading dislocation density. The tilt and twist disorders of the epilayer were also significantly reduced. The compressive stress in the epilayers at room temperature increased as the N/Ga flux ratio during the buffer layer growth was reduced. The improved properties of the epilayers are explained by the hypothesis that excess Ga in the buffer layer facilitates stress relaxation at the epilayer growth temperature. (C) 2000 American Institute of Physics. [S0021-8979(00)00223-1]. C1 Univ Calif Berkeley, Dept Mat Sci & Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Kim, Y (reprint author), Univ Calif Berkeley, Dept Mat Sci & Engn, Berkeley, CA 94720 USA. RI Liliental-Weber, Zuzanna/H-8006-2012 NR 23 TC 19 Z9 21 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD NOV 15 PY 2000 VL 88 IS 10 BP 6032 EP 6036 DI 10.1063/1.1319162 PG 5 WC Physics, Applied SC Physics GA 369MA UT WOS:000165068700082 ER PT J AU Zerkle, DK Allendorf, MD Wolf, M Deutschmann, O AF Zerkle, DK Allendorf, MD Wolf, M Deutschmann, O TI Understanding homogeneous and heterogeneous contributions to the platinum-catalyzed partial oxidation of ethane in a short-contact-time reactor SO JOURNAL OF CATALYSIS LA English DT Article DE ethane; partial oxidation; ethylene; oxidative dehydrogenation; catalysis; platinum; computational fluid dynamics; reactor simulation ID PT(111) SURFACE; COATED MONOLITHS; CRYSTAL-SURFACES; C-2 HYDROCARBONS; PT/MGO CATALYST; MOLECULAR-BEAM; ETHYLENE; DEHYDROGENATION; METHANE; KINETICS AB This paper describes a computational study of the partial oxidation of ethane to ethylene in a short-contact-time reactor, using a two-dimensional computational fluid dynamics model with full heat and mass transport. Detailed heterogeneous and homogeneous chemical kinetic mechanisms are employed to describe the chemistry. Rate constants for elementary surface reactions are determined from literature sources or by fitting model predictions to experimental data. Simulations using these mechanisms suggest that platinum-catalyzed heterogeneous chemical processes are responsible for the oxidation of surface carbon and hydrogen, resulting in localized heat release into the gas phase. This heat release drives endothermic homogeneous and heterogeneous cracking of ethane to ethylene and H-2. The proportion of homogeneous and heterogeneous contributions depends strongly upon the reactor operating conditions. In addition to predictions of ethane conversion and ethylene selectivity, the model also predicts the production of all other major products: H2O, H-2, CH4, CO, and CO2. A good fit is obtained between model predictions and experimental data for ethane/oxygen mixtures. The model is applied to ethane/ hydrogen/oxygen mixtures and good agreement with this set of experimental. data is also obtained. (C) 2000 Academic Press. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Tehcnol Div, Los Alamos, NM 87545 USA. Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. Univ Heidelberg, Interdisziplinares Zentrum Wissenshaftliches Rech, Heidelberg, Germany. RP Zerkle, DK (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Tehcnol Div, POB 1663,Mail Stop 1567, Los Alamos, NM 87545 USA. RI Deutschmann, Olaf/B-4891-2015 OI Deutschmann, Olaf/0000-0001-9211-7529 NR 78 TC 108 Z9 109 U1 3 U2 27 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9517 J9 J CATAL JI J. Catal. PD NOV 15 PY 2000 VL 196 IS 1 BP 18 EP 39 DI 10.1006/jcat.2000.3009 PG 22 WC Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA 378RV UT WOS:000165598200003 ER PT J AU Li, YM Francisco, JS Peterson, KA AF Li, YM Francisco, JS Peterson, KA TI A complete active space self-consistent field multireference configuration interaction study of the low-lying excited states of BrO SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID GAUSSIAN-BASIS SETS; CORRELATED MOLECULAR CALCULATIONS; SPECTROSCOPY; ATOMS; SPECTRUM; ABSORPTION; TRANSITION; ENERGIES; CLO; OH AB A theoretical study of the excited states of the BrO radical has been carried out for the first time using high level ab initio molecular orbital methods. The vertical excitation energies for the low-lying excited states (2 (2)Pi, 1 (2)Sigma (+), 1 (2)Sigma (-) and 1 (2)Delta) are calculated using the internally contracted multireference configuration interaction (MRCI) method. Based on vertical excitation energies, the ordering of the first few excited states are determined to be 2 (2)Pi, 1 (2)Delta, 1 (2)Sigma (-), and 1 (2)Sigma (+). The potential energy curves for the ground state (X (2)Pi) and several low-lying excited states are examined at the MRCI+Q/aug-cc-pVQZ level of theory. Several excited states are calculated to intersect the 2 (2)Pi state, resulting in predissociation into Br(P-2)+O(P-3). Results for the quartet states of BrO are also included, as well as calculations of the effects of spin-orbit coupling on the electronic states of BrO. (C) 2000 American Institute of Physics. [S0021-9606(00)31243-0]. C1 Purdue Univ, Dept Chem, W Lafayette, IN 47907 USA. Purdue Univ, Dept Earth & Atmospher Sci, W Lafayette, IN 47907 USA. Washington State Univ, Dept Chem, Richland, WA 99352 USA. Pacific NW Natl Lab, William R Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Li, YM (reprint author), Purdue Univ, Dept Chem, W Lafayette, IN 47907 USA. NR 37 TC 13 Z9 13 U1 0 U2 7 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD NOV 15 PY 2000 VL 113 IS 19 BP 8556 EP 8560 AR PII [S0021-9606(00)31243-0] DI 10.1063/1.1318751 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 369TR UT WOS:000165083500017 ER PT J AU Dressler, RA Chiu, YH Levandier, DJ Ng, CY AF Dressler, RA Chiu, YH Levandier, DJ Ng, CY TI Collision-induced dissociation dynamics in O-2(+)+Ne(Ar) collisions: The role of electronic excitation SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID GUIDED-ION BEAM; RESOLUTION PHOTOFRAGMENT SPECTROSCOPY; 1ST NEGATIVE SYSTEM; CHARGE-TRANSFER; LOW ENERGIES; PREDISSOCIATION; PHOTOELECTRON; LASER; O-2 AB Integral collision-induced dissociation (CID) cross sections at center-of-mass (CM) energies ranging from threshold to 22 eV and product ion recoil velocity distributions are presented for O-2(+)+Ne(Ar) collisions. The O-2(+) ions are produced in an electron impact ion source and thus have similar to0.5 eV of vibrational energy. The O-2(+)+Ne CID cross sections are observed at energies below the 0 K thermodynamic threshold of 6.66 eV, implying the possibility of significant vibrational effects. A second CID threshold is apparent at 9 +/-1 eV. This is close to the charge-transfer (CT) threshold energy. No CT products are observed. The O-2(+)+Ar CID cross section rises rapidly above a relative translational energy onset of 7.5 +/-0.2 eV and reaches a maximum value of similar to0.8 Angstrom (2) at 14 eV (CM). A CT onset of 6.0 +/-0.2 eV is observed which is close to the thermodynamic threshold for CID. The energy dependence of the CT cross section is very similar to the CID cross section except for a small step at energies where CID becomes efficient. The CID recoil velocity distributions near threshold are centered at the CM velocity and shift to forward preference at higher energies. The O-2(+)+Ar CT recoil velocities are forward scattered near threshold and become centered with respect to the CM velocity at energies where competition with CID is apparent. (C) 2000 American Institute of Physics. [S0021-9606(00)00243-9]. C1 USAF, Res Lab, Space Vehicles Directorate, Hanscom AFB, MA 01731 USA. Boston Coll, Inst Sci Res, Newton, MA 02159 USA. Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP USAF, Res Lab, Space Vehicles Directorate, Hanscom AFB, MA 01731 USA. NR 35 TC 6 Z9 6 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD NOV 15 PY 2000 VL 113 IS 19 BP 8561 EP 8566 AR PII [S0021-9606(00)00243-9] DI 10.1063/1.1317550 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 369TR UT WOS:000165083500018 ER PT J AU Choi, H Taylor, TR Bise, RT Hoops, AA Neumark, DM AF Choi, H Taylor, TR Bise, RT Hoops, AA Neumark, DM TI Excited states and photodissociation dynamics of the triiodine radical (I-3) SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID FEMTOSECOND PHOTOELECTRON-SPECTROSCOPY; FAST BEAM; SPECTRUM; PHOTODETACHMENT; TRANSITION; ENERGY; IONS; I2 AB The electronic spectroscopy and photodissociation dynamics of the I-3 radical are investigated with two experimental methods. The ground and several low-lying excited states of the I-3 radical are characterized by photoelectron spectroscopy of I-3(-) at 213 nm. Assignments of these states are discussed with reference to recent calculations. In addition, photodissociation of the I-3 radical was investigated at selected photon energies (4.59, 4.96, and 5.17 eV) by fast radical beam photofragment translational spectroscopy. Two product channels were observed with mass ratios of 1:2 and 1:1, and translational energy (P(E-T)) distributions were measured. The P(E-T) distributions for products with mass ratio 1:2 show that this channel corresponds to I-2 in various electronic states along with atomic I in its P-2(3/2) or P-2(1/2) state. The 1:1 channel corresponds primarily to concerted three-body dissociation to three I atoms. (C) 2000 American Institute of Physics. [S0021-9606(00)01043-6]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Lam Res, Fremont, CA 94538 USA. Lucent Technol, Murray Hill, NJ 07974 USA. RP Choi, H (reprint author), Univ Calif Los Angeles, Dept Chem & Biochem, Los Angeles, CA 90095 USA. RI Neumark, Daniel/B-9551-2009 OI Neumark, Daniel/0000-0002-3762-9473 NR 32 TC 7 Z9 7 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD NOV 15 PY 2000 VL 113 IS 19 BP 8608 EP 8614 DI 10.1063/1.1318755 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 369TR UT WOS:000165083500024 ER PT J AU Moore, JD Cui, ST Cochran, HD Cummings, PT AF Moore, JD Cui, ST Cochran, HD Cummings, PT TI Rheology of lubricant basestocks: A molecular dynamics study of C-30 isomers SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID BRANCHED ALKANES; EXTREME CONFINEMENT; PHASE-EQUILIBRIA; SHEAR BEHAVIOR; TRANSFERABLE POTENTIALS; SELF-DIFFUSION; N-ALKANES; SIMULATION; VISCOSITY; TETRACOSANE AB We have performed extensive equilibrium and nonequilibrium molecular dynamics (EMD and NEMD) simulations of three isomers of C30H62 at temperatures of 311 and 372 K employing a united atom model. Using the rotational relaxation time calculated from the EMD simulation, the Rouse model predicts a zero-shear viscosity for n-triacontane within 16% of the value determined by NEMD. Compared to experiment, NEMD and the united atom model underpredict the kinematic viscosities of n-triacontane and 9-n-octyldocosane but accurately predict the values for squalane (within 15%). In addition, the predicted values of the kinematic viscosity index for both 9-n-octyldocosane and squalane are in quantitative agreement with experiment and represent the first such predictions by molecular simulation. This same general potential model and computational approach can be used to predict this important lubricant property for potential lubricants prior to their synthesis, offering the possibility of simulation-guided lubricant design. (C) 2000 American Institute of Physics. [S0021-9606(00)50643-6]. C1 Univ Tennessee, Dept Chem Engn, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Univ Tennessee, Dept Comp Sci, Knoxville, TN 37996 USA. RP Cummings, PT (reprint author), Univ Tennessee, Dept Chem Engn, Knoxville, TN 37996 USA. RI Moore, Jonathan/B-8201-2009; Cummings, Peter/B-8762-2013 OI Cummings, Peter/0000-0002-9766-2216 NR 48 TC 45 Z9 46 U1 0 U2 11 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD NOV 15 PY 2000 VL 113 IS 19 BP 8833 EP 8840 DI 10.1063/1.1318768 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 369TR UT WOS:000165083500051 ER PT J AU Zanni, MT Davis, AV Frischkorn, C Elhanine, M Neumark, DM AF Zanni, MT Davis, AV Frischkorn, C Elhanine, M Neumark, DM TI Femtosecond stimulated emission pumping: Characterization of the I-2(-) ground state" (vol 112, pg 8847, 2000) SO JOURNAL OF CHEMICAL PHYSICS LA English DT Correction C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Paris 11, CNRS, Photophys Mol Lab, F-91405 Orsay, France. RP Zanni, MT (reprint author), Univ Penn, Dept Chem, Philadelphia, PA 19104 USA. RI Zanni, Martin/K-2707-2013; Neumark, Daniel/B-9551-2009 OI Neumark, Daniel/0000-0002-3762-9473 NR 1 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD NOV 15 PY 2000 VL 113 IS 19 BP 8854 EP 8854 DI 10.1063/1.1318753 PG 1 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 369TR UT WOS:000165083500055 ER PT J AU Trainor, TP Brown, GE Parks, GA AF Trainor, TP Brown, GE Parks, GA TI Adsorption and precipitation of aqueous Zn(II) on alumina powders SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article DE adsorption; zinc; coprecipitation; alumina ID AMORPHOUS IRON OXYHYDROXIDE; BOND-VALENCE DETERMINATION; RAY-ABSORPTION-SPECTRA; SURFACE COMPLEXATION; ZINC ADSORPTION; EXCHANGE STOICHIOMETRY; CATION DISTRIBUTION; SORPTION PRODUCTS; PH-DEPENDENCE; NEUTRAL PH AB The products of aqueous Zn(II) sorption on high-surface-area alumina powders (Linde-A) have been studied using XAFS spectroscopy as a function of Zn(II) sorption density (Gamma = 0.2 to 3.3 mu mol/m(2)) at pH values of 7.0 to 8.2. Over equilibration times of 15-111 h, we find that at low sorption densities (Gamma = 0.2-1.1 mu mol/m(2)) Zn(II) forms predominantly inner-sphere bidentate surface complexes with AlO(6) polyhedra, whereas at higher sorption densities (Gamma = 1.5 to 3.5 mu mol/m(2)), we find evidence for the formation of a mixed-metal Zn(II)-Al(III) hydroxide coprecipitate with a hydrotalcite-type local structure. These conclusions are based on an analysis of first- and second-neighbor interatomic distances derived from EXAFS spectra collected under ambient conditions on wet samples. At low sorption densities the sorption mechanism involves a transformation from six-coordinated Zn-hexaaquo solution complexes (with an average Zn-O distance of 2.07 Angstrom) to four-coordinated surface complexes (with an average Zn-O distance of 1.97 Angstrom) as described by the reaction =Al(OH(a))(OH(b)) + Zn(H(2)O)(6)(2+) --> =Al(OH(a'))(OH(b'))Zn(OH(c'))(OH(d')) + 4H(2)O + zH(+), where =Al(OH(a))(OH(b)) represents edge-sharing sites of Al(O,OH,OH(2))(6) octahedra to which Zn(O,OH,OH(2))(4) bonds in a bidentate fashion. The proton release consistent with this reaction (z = a-a' + b-b' + 4-c'-d'), and with bond valence analysis falls in the range of O to 2 H(+)/Zn(II) when hydrolysis of the adsorbed Zn(II) complex is neglected. This interpretation suggests that proton release is likely a strong function of the coordination chemistry of the surface hydroxyl groups. At higher sorption densities (1.5 to 3.5 mu mol/m(2)), a high-amplitude, second-shell feature in the Fourier transform of the EXAFS spectra indicates the formation of a three-dimensional mixed-metal coprecipitate, with a hydrotalcite-like local structure. Nitrate anions presumably satisfy the positive layer charge of the Al(III)-Zn(II) hydroxide layers in which the Zn/Al ratio falls in the range of 1:1 to 2:1. Our results for the higher Gamma -value sorption samples suggest that Zn-hydrotalcite-like phases may be a significant sink for Zn(II) in natural or catalytic systems containing soluble alumina compounds. (C) 2000 Academic Press. C1 Stanford Univ, Dept Geol & Environm Sci, Surface & Aqueous Geochem Grp, Stanford, CA 94305 USA. Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Trainor, TP (reprint author), Stanford Univ, Dept Geol & Environm Sci, Surface & Aqueous Geochem Grp, Stanford, CA 94305 USA. EM trainor@pangea.stanford.edu NR 80 TC 115 Z9 120 U1 1 U2 24 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9797 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD NOV 15 PY 2000 VL 231 IS 2 BP 359 EP 372 DI 10.1006/jcis.2000.7111 PG 14 WC Chemistry, Physical SC Chemistry GA 371VD UT WOS:000165199200017 ER PT J AU Buttrey, DJ Vogt, T White, BD AF Buttrey, DJ Vogt, T White, BD TI High-temperature incommensurate-to-commensurate phase transition in the Bi2MoO6 catalyst SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article ID POWDER NEUTRON-DIFFRACTION; BISMUTH MOLYBDATE; CRYSTAL-STRUCTURE; SELECTIVE OXIDATION; REFINEMENT AB The temperature-dependent behavior of the low- and intermediate-temperature phases of gamma -Bi2MoO6 were investigated, As revealed by high-resolution neutron and synchrotron powder diffraction as well as electron diffraction, the low-temperature Aurivillius phase shows a previously undetected incommensurate modulation: along the pseudo-tetragonal a (q(a) = 0.5626(2)) and c (q(c) = 0.2844(2)) axes, A reversible incommensurate-to-commensurate phase transition to the intermediate-temperature phase occurs near 840 K, before irreversibly transforming near 880 K into the fluorite-related high-temperature polymorph described in detail by two of us in an earlier study (Buttrey et al,, J, Solid State Chem. 111, 118-127 (1994)), (C) 2000 Academic Press. C1 Univ Delaware, Ctr Catalyt Sci & Technol, Dept Chem Engn, Newark, DE 19716 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Buttrey, DJ (reprint author), Univ Delaware, Ctr Catalyt Sci & Technol, Dept Chem Engn, Newark, DE 19716 USA. RI Vogt, Thomas /A-1562-2011 OI Vogt, Thomas /0000-0002-4731-2787 NR 31 TC 28 Z9 31 U1 0 U2 17 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD NOV 15 PY 2000 VL 155 IS 1 BP 206 EP 215 DI 10.1006/jssc.2000.8935 PG 10 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA 378QL UT WOS:000165595000027 ER PT J AU Mozharivskyj, Y Kaczorowski, D Franzen, HF AF Mozharivskyj, Y Kaczorowski, D Franzen, HF TI Symmetry-breaking transitions from GdCuAs2 through GdCuAs1.15P0.85 to GdCuP2.20: Crystal structure, application of landau theory, bonding, magnetic and electrical properties SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article ID RARE-EARTH; ELEMENTS; CE; CU AB The crystal structures of GdCuAs2, GdCuAs1.15P0.85, and GdCuP2.20 have been investigated by the single crystal and powder methods. While GdCuAs2 (P4/nmm) retains the tetragonal HfCuSi2 structure (M. Brylak, M, H. Moller, and W, Jeitschko, J, Solid State Chem. 115, 305 (1995)), GdCuAs1.15P0.85 (Pmmn, a = 3,849(1), b = 3,8501(1), c = 9.871(3) Angstrom) and GdCuP2.20 (Pmm2, a = 5,3747(9), b = 5,3830(9), c = 9.7376(16) Angstrom) undergo orthorhombic distortions. The changes are significant in GdCuP2.20: P dimers are formed in the P layer along the a direction and there is an additional (but deficient) P site on one side of the layer that links the dimers, The GdCuAs1.15P0.85 structure was predicted by the Landau theory. According to this theory the transition from GdCuAs2 to GdCuAs1.15P0.85 can be a continous one, the transition from GdCuAs1.15P0.85 to GdCuP2.20 is a first-order one. The transition to GdCuP2.20 occurs with twin formation, The electronic structure and bonding are analyzed by the extended Huckel tight-binding method. The conductivity and magnetic measurements for the arsenide and phosphide are reported, (C) 2000 Academic Press. C1 Iowa State Univ, Ames Lab, US DOE, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Polish Acad Sci, W Trzebiatowski Inst Low Temp & Struct Res, PL-50950 Wroclaw, Poland. RP Franzen, HF (reprint author), Iowa State Univ, Ames Lab, US DOE, 342 Spedding Hall, Ames, IA 50011 USA. RI Kaczorowski, Dariusz/M-6572-2014 NR 50 TC 30 Z9 30 U1 1 U2 4 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD NOV 15 PY 2000 VL 155 IS 1 BP 259 EP 272 DI 10.1006/jssc.2000.8962 PG 14 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA 378QL UT WOS:000165595000035 ER PT J AU Aytug, T Wu, JZ Kang, BW Verebelyi, DT Cantoni, C Specht, ED Goyal, A Paranthaman, M Christen, DK AF Aytug, T Wu, JZ Kang, BW Verebelyi, DT Cantoni, C Specht, ED Goyal, A Paranthaman, M Christen, DK TI An all-sputtered buffer layer architecture for high-J(c) YBa2Cu3O7-delta coated conductors SO PHYSICA C LA English DT Article DE high-temperature superconductors; YBa2Cu3O7-delta; LaNiO3; sputtering; buffer layers ID ELECTRON-BEAM EVAPORATION; CRITICAL-CURRENT DENSITY; TEXTURED NI TAPES; SUPERCONDUCTING TAPES; YBCO FILMS; DEPOSITION; GROWTH AB We report the development of an all-sputter-deposited buffer multilayer architecture for the growth of high critical current density (J(c)) YBa2CU3O7-delta (YBCO) films on metallic tapes. The structure comprises the layer sequence of CeO2/YSZ/LNO (YSZ: yttria stabilized zirconia, LNO: LaNiO3) on biaxially textured Ni substrates. X-ray diffraction analysis of the base LaNiO3 (LNO) layers indicated that well textured films can be obtained at deposition temperatures (T-dep) between 450 degreesC and 500 degreesC, while higher T-dep yielded polycrystalline films. The degree of LNO crystallinity was also influenced by the oxygen partial pressure during the growth. Scanning electron microscopy observations revealed a smooth, dense and crack-free surface morphology, independent of film thickness in the range of 50-300 nm. Subsequent YSZ and CeO2 films were deposited to complete the buffer-layer structure. Epitaxial YBCO films grown by pulsed laser ablation on the CeO2/YSZ/LNO/Ni multilayer structure have self-field J(c) values as high as 1.3 x 10(6) A/cm(2) at 77 K, Effects of the LNO base-layer thickness on the quality of buffers and on the superconducting properties of YBCO films showed no remarkable differences, The present results demonstrate a viable approach for the production of long length YBCO superconducting wires. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA. RP Aytug, T (reprint author), Oak Ridge Natl Lab, Bldg 3115,MS-6061,Bethel Valley Rd,POB 2008, Oak Ridge, TN 37831 USA. RI Specht, Eliot/A-5654-2009; Paranthaman, Mariappan/N-3866-2015; Cantoni, Claudia/G-3031-2013 OI Specht, Eliot/0000-0002-3191-2163; Paranthaman, Mariappan/0000-0003-3009-8531; Cantoni, Claudia/0000-0002-9731-2021 NR 15 TC 10 Z9 11 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 NOV 15 PY 2000 VL 340 IS 1 BP 33 EP 40 DI 10.1016/S0921-4534(00)01331-9 PG 8 WC Physics, Applied SC Physics GA 377ZB UT WOS:000165555400003 ER PT J AU Alda, W Yuen, DA Luthi, HP Rustad, JR AF Alda, W Yuen, DA Luthi, HP Rustad, JR TI Exothermic and endothermic chemical reactions involving very many particles modeled with molecular dynamics SO PHYSICA D LA English DT Article DE exothermic and endothermic reactions; molecular dynamics; Lennard-Jones potential ID PHASE-SEPARATION; SIMULATIONS; DIFFUSION; SYSTEMS; INSTABILITY; SURFACES; AUTOMATA AB The traditional continuum approach of modeling chemical reactions with specified kinetic rates suffers from numerical difficulties in reactive flows and other highly non-equilibrium situations due to the stiffness of the differential equations in both space and time. These drawbacks can be eliminated within the framework of the discrete-particle approach in which the chemical reactions are modeled by means of two-body interparticle potentials with classical molecular dynamics. Here we present a simple model for prescribing the binary endothermic and exothermic reactions of the type A + B --> C, in the presence of many (greater than 10(4)) reacting particles. Two-body Lennard-Jones based potentials, V-ij, have been utilized, in which the reaction takes place via an attractive potential V-AB With a deep enough potential well. The other potentials V-AC and V-BC have deeper wells than V-AB for creating a suitable situation for inducing exothermic reactions, while a high-energy plateau for V-AC and V-BC is used for simulating endothermic reactions. We have deployed 20 000 to 100 000 particles in a computational domain with an area of around 1 million Angstrom (2). These ensembles have all been integrated out to around the order of nanoseconds. We have examined the bimolecular reactions between two layers initially consisting of A particles lying atop B particles, equally divided in the total population. Reactions take place first along this boundary. There is a nonlinear threshold phenomenon in the exothermic reactions, which are greatly accelerated by the heat liberated from the neighboring reactions. In contrast, the endothermic reactions are more subdued, as there is no positive feedback. Exothermic reactions occur in a spatially heterogeneous manner, especially at the lower temperatures, in which no single reaction rate can be assigned to the entire reaction front. More coherent spatial structures are found with decreasing temperature. These spatial structures can influence the overall flow field associated with the motions of the reacting particles. Timescales of the reactions are greatly lengthened by a reduction in the temperature in a threshold manner. (C) 2000 Published by Elsevier Science B.V. C1 Univ Minnesota, Dept Geol & Geophys, Minneapolis, MN 55415 USA. Stanislaw Staszic Univ Min & Met, Inst Comp Sci, PL-30059 Krakow, Poland. Univ Minnesota, Minnesota Supercomp Inst, Minneapolis, MN 55415 USA. Swiss Fed Inst Technol, Swiss Ctr Sci Comp, CH-8092 Zurich, Switzerland. Pacific NW Natl Lab, WR Wiley EMSL, Richland, WA 99352 USA. RP Yuen, DA (reprint author), Univ Minnesota, Dept Geol & Geophys, 1200 Washington Ave S, Minneapolis, MN 55415 USA. NR 31 TC 3 Z9 3 U1 1 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-2789 J9 PHYSICA D JI Physica D PD NOV 15 PY 2000 VL 146 IS 1-4 BP 261 EP 274 DI 10.1016/S0167-2789(00)00150-0 PG 14 WC Mathematics, Applied; Physics, Multidisciplinary; Physics, Mathematical SC Mathematics; Physics GA 370HG UT WOS:000165117000011 ER PT J AU Perebeinos, V Allen, PB Weinert, M AF Perebeinos, V Allen, PB Weinert, M TI First-principles calculations of the self-trapped exciton in crystalline NaCl SO PHYSICAL REVIEW B LA English DT Article ID ALKALI-HALIDE CRYSTALS; RESONANCE-RAMAN-SCATTERING; KCL; SPECTROSCOPY; STATE; LIGHT AB The atomic and electronic structure of the lowest triplet state of the off-center (C-2 nu symmetry) self-trapped exciton in crystalline NaCl is calculated using the local-spin-density (LSDA) approximation. In addition, the Franck-Condon broadening of the luminescence peak and the a(1g) --> b(3u) absorption peak are calculated and compared to experiment. LSDA accurately predicts transition energies if the initial and final states are both localized or delocalized, but I eV discrepancies with experiment occur if one state is localized and the other is delocalized. C1 SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Perebeinos, V (reprint author), SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. NR 33 TC 7 Z9 7 U1 0 U2 7 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 NOV 15 PY 2000 VL 62 IS 19 BP 12589 EP 12592 DI 10.1103/PhysRevB.62.12589 PG 4 WC Physics, Condensed Matter SC Physics GA 374XJ UT WOS:000165369700007 ER PT J AU Rasmussen, T AF Rasmussen, T TI Simulation of misfit dislocation loops at the Ag/Cu(111) interface SO PHYSICAL REVIEW B LA English DT Article ID SCANNING-TUNNELING-MICROSCOPY; FIRST-PRINCIPLES; METALS; TRANSITION; ENERGY AB Molecular dynamics simulations combined with the nudged elastic band method for finding transition states and corresponding activation energies are used to study mechanisms of nucleation, growth, and motion of misfit dislocation loops at the Ag/Cu(111) interface. A variety of mechanisms involving concerted motion of several atoms are identified. Nucleation has the highest activation energy, similar to1 eV. Growth and motion of the loops have activation energies in the range 0.3-0.7 eV. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Rasmussen, T (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 15 TC 11 Z9 11 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD NOV 15 PY 2000 VL 62 IS 19 BP 12664 EP 12667 DI 10.1103/PhysRevB.62.12664 PG 4 WC Physics, Condensed Matter SC Physics GA 374XJ UT WOS:000165369700026 ER PT J AU Qualls, JS Mielke, CH Brooks, JS Montgomery, LK Rickel, DG Harrison, N Han, SY AF Qualls, JS Mielke, CH Brooks, JS Montgomery, LK Rickel, DG Harrison, N Han, SY TI High-magnetic-field phase diagram of a quasi-one-dimensional metal SO PHYSICAL REVIEW B LA English DT Article ID SPIN-DENSITY-WAVE; QUANTUM OSCILLATIONS; RAPID OSCILLATION; CONDUCTOR; (TMTSF)(2)CLO4; (TMTSF)2X AB We report the high magnetic-field phase (to 45 T) of the quasi-one-dimensional organic conductor (TMTSF)(2)ClO4 in its thermally quenched phase. Termed ''Q-ClO4," this phase exhibits a spin-density-wave (SDW) transition at approximate to5 K which is strongly magnetic-field dependent, and distinct from the phase extensively studied in the annealed material. The field dependence of the SDW transition is well modeled by the theoretical treatment of Bjelis and Maki. We discuss the B-T phase diagram of Q-ClO4 in the context of the hierarchy of low-dimensional organic metals (one-dimensional towards two-dimensional), and describe the temperature dependence of the quantum oscillations observed in the SDW phase. C1 Florida State Univ, NHMFL, Tallahassee, FL 32310 USA. Los Alamos Natl Lab, NHMFL, Los Alamos, NM 87545 USA. Indiana Univ, Dept Chem, Bloomington, IN 47405 USA. RP Florida State Univ, NHMFL, Tallahassee, FL 32310 USA. RI Mielke, Charles/S-6827-2016 OI Mielke, Charles/0000-0002-2096-5411 NR 18 TC 13 Z9 14 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD NOV 15 PY 2000 VL 62 IS 19 BP 12680 EP 12683 DI 10.1103/PhysRevB.62.12680 PG 4 WC Physics, Condensed Matter SC Physics GA 374XJ UT WOS:000165369700030 ER PT J AU Su, T Chen, S Taylor, PC Crandall, RS Mahan, AH AF Su, T Chen, S Taylor, PC Crandall, RS Mahan, AH TI Molecular hydrogen in hydrogenated amorphous silicon: NMR evidence SO PHYSICAL REVIEW B LA English DT Article ID A-SI-H; ALPHA-SI; H-2 AB We measured the concentrations of molecular hydrogen in hydrogenated amorphous silicon (a-Si:H) using a Jeener-Brockaert three-pulse sequence. For samples prepared by both plasma-enhanced chemical vapor deposition (PECVD) and hot wire chemical vapor deposition (HWCVD), the molecular hydrogen concentrations are about one order of magnitude larger than those inferred from spin-lattice-relaxation time (T-1) measurements. There are two distinct environments for hydrogen molecules. In one the molecules are essentially isolated and act as relaxation centers for hydrogen bonded to silicon atoms. In the other, the hydrogen molecules are clustered and do not relax the bonded hydrogen. Samples prepared by HWCVD have a lower transition temperature for freezing of the molecular hydrogen motion than those prepared by PECVD. This behavior is attributed to a more ordered silicon structure in HWCVD samples. The nonexponential behavior of the dipolar relaxation and possible relation with the defects and doping is discussed. C1 Univ Utah, Dept Phys, Salt Lake City, UT 84112 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Su, T (reprint author), Univ Utah, Dept Phys, Salt Lake City, UT 84112 USA. NR 38 TC 27 Z9 27 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 NOV 15 PY 2000 VL 62 IS 19 BP 12849 EP 12858 DI 10.1103/PhysRevB.62.12849 PG 10 WC Physics, Condensed Matter SC Physics GA 374XJ UT WOS:000165369700052 ER PT J AU Teklu, AA Goodrich, RG Harrison, N Hall, D Fisk, Z Young, D AF Teklu, AA Goodrich, RG Harrison, N Hall, D Fisk, Z Young, D TI Fermi surface properties of low-concentration CexLa1-xB6: de Haas-van Alphen SO PHYSICAL REVIEW B LA English DT Article ID MAGNETIC-FIELD DEPENDENCE; KONDO LATTICE CEB6; CYCLOTRON MASS; QUANTUM INTERFERENCE; ORBITAL DEGENERACY; QUASI-PARTICLE; COMPOUND CEB6; VANALPHEN; DEHAAS; LAB6 AB The de Haas-van Alphen (dHvA) effect is used to study angular-dependent extremal areas of the Fermi surfaces and effective masses of CexLa1-xB6 alloys for x between 0 and 0.05. The dHvA signals from these alloys are observed to change from that arising from the normal two-spin metal, LaB6, to a single-spin sheet signal at x = 0.05. C1 Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA. LANL, Natl High Magnet Field Lab, Los Alamos, NM 87545 USA. Florida State Univ, Natl High Magnet Field Lab, Tallahassee, FL 32310 USA. RP Teklu, AA (reprint author), Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA. NR 34 TC 14 Z9 14 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 NOV 15 PY 2000 VL 62 IS 19 BP 12875 EP 12881 DI 10.1103/PhysRevB.62.12875 PG 7 WC Physics, Condensed Matter SC Physics GA 374XJ UT WOS:000165369700055 ER PT J AU Williamson, AJ Wang, LW Zunger, A AF Williamson, AJ Wang, LW Zunger, A TI Theoretical interpretation of the experimental electronic structure of lens-shaped self-assembled InAs/GaAs quantum dots SO PHYSICAL REVIEW B LA English DT Article ID PSEUDOPOTENTIAL CALCULATION; EXCITONIC TRANSITIONS; ENERGY-LEVELS; BAND; SPECTROSCOPY; STATES; GAAS; ABSORPTION; COULOMB; SPECTRA AB We adopt an atomistic pseudopotential description of the electronic structure of self-assembled, lens-shaped InAs quantum dots within the "linear combination of bulk bands" method. We present a detailed comparison with experiment, including quantites such as the single-particle electron and hole energy level spacings, the excitonic band gap, the electron-electron, hole-hole, and electron-hole Coulomb energies and the optical polarization anisotropy. We find a generally good agreement, which is improved even further for a dot composition where some Ga has diffused into the dots. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Williamson, AJ (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RI Zunger, Alex/A-6733-2013 NR 58 TC 264 Z9 265 U1 2 U2 25 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 NOV 15 PY 2000 VL 62 IS 19 BP 12963 EP 12977 DI 10.1103/PhysRevB.62.12963 PG 15 WC Physics, Condensed Matter SC Physics GA 374XJ UT WOS:000165369700067 ER PT J AU Akola, J Manninen, M Hakkinen, H Landman, U Li, X Wang, LS AF Akola, J Manninen, M Hakkinen, H Landman, U Li, X Wang, LS TI Aluminum cluster anions: Photoelectron spectroscopy and ab initio simulations SO PHYSICAL REVIEW B LA English DT Article ID DENSITY-FUNCTIONAL THEORY; ELECTRON-REMOVAL ENERGIES; TRANSITION-METAL CLUSTERS; S-P HYBRIDIZATION; SHELL-STRUCTURE; DERIVATIVE DISCONTINUITIES; CU-N(-) CLUSTERS; SPECTRA; TEMPERATURE; POLARIZABILITIES AB Atomic structures and geometries, electronic structure, and temperature-dependent photoelectron spectra of Al-N(-) (N = 19-102) clusters are studied both theoretically via ab initio local-density-functional simulations, and experimentally with high-resolution measurements. The use of a theoretically well-defined energy shift in conjunction with a generalized Koopmans' theorem enables direct comparisons between the calculated density of states and the experimental photoelectron spectrum. Such comparisons, using photoelectron spectra calculated for various relaxed cluster geometries, enables a determination of the optimal structures of the clusters. The atomic arrangements in the ground-state structures of Al-19(-), Al-20(-), and Al-23(-) are found and they exhibit oblate, prolate, and octupole deformed shapes, respectively. In addition to the low-temperature spectra, high temperature calculated spectra of these clusters obtained via ab initio molecular-dynamics simulations reproduce the experimentally observed trends measured for hot clusters. For larger cluster anions (N greater than or equal to 36), the level of agreement between the theoretically calculated spectra and the measured ones is less satisfactory, indicating that while certain structural motifs are identified, the optimal ground-state structures may not have been fully determined. fee-like low-energy structures are found in the larger cluster-size range, with decreasing distortions of the internal structures when the cluster size is increased. Indications are found pertaining to an octahedral growth pattern of larger aluminum clusters. C1 Univ Jyvaskyla, Dept Phys, FIN-40351 Jyvaskyla, Finland. Georgia Inst Technol, Sch Phys, Atlanta, GA 30332 USA. Washington State Univ, Dept Phys, Richland, WA 99352 USA. Pacific NW Natl Lab, WR Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Univ Jyvaskyla, Dept Phys, FIN-40351 Jyvaskyla, Finland. RI Akola, Jaakko/L-6076-2013; OI Akola, Jaakko/0000-0001-9037-7095; Manninen, Matti/0000-0001-6927-7698 NR 54 TC 89 Z9 92 U1 1 U2 10 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 NOV 15 PY 2000 VL 62 IS 19 BP 13216 EP 13228 DI 10.1103/PhysRevB.62.13216 PG 13 WC Physics, Condensed Matter SC Physics GA 374XJ UT WOS:000165369700104 ER PT J AU Qian, Q Tyson, TA Kao, CC Croft, M Cheong, SW Greenblatt, M AF Qian, Q Tyson, TA Kao, CC Croft, M Cheong, SW Greenblatt, M TI Thermal effects in the x-ray spectra of La1-xCaxMnO3 SO PHYSICAL REVIEW B LA English DT Article ID MN K-EDGE; DOUBLE EXCHANGE; VALENCE; SPECTROSCOPY; TRANSITION; MAGNETISM; EMISSION; STATE; LA(1-X)A(X)MNO(3); MAGNETORESISTANCE AB Complementary x-ray emission (XES) and x-ray-absorption (XAS) measurements of La1-xCaxMnO3 as a function of temperature have been performed. For 0.5 less than or equal tox less than or equal to0.8 we find changes in the XAS and XES spectra consistent with a small increase in the average Mn valence accompanying the passage to the low-temperature state. It is suggested that this small Mn-configuration shift could be due to the competition between the energies associated with ferromagnetic (FM) and charge/orbital (CO) correlations. In the region 0.0 less than or equal tox less than or equal to0.4 we observe thermal spectral changes quite different from those found in the x greater than or equal to0.5 materials. Modest thermal changes in the Mn XAS pre-edge (K-edge), for 0.0 less than or equal ton less than or equal to0.4, were observed to be coupled to the robustness of the;FM-metallic ground state. The dearest pre-edge feature variation appears to be related to Mn-e(g)-majority-spin state changes. In contrast the thermal XES spectral changes appear similar in character in the antiferromagnetic (AF)-insulating x=0.0 and FM-metallic x=0.3 materials. An enhancement of the effective local moment via a coupling to the internal exchange held, in the magnetically ordered states, is Proposed to explain these XES results. The x=1.0 end member (CaMnO3) was found to exhibit significant temperature dependence of the absorption and emission spectra. These XAS and XES results, for CaMnO3, are discussed in terms of thermal perturbations on the degree of covalency of this material. C1 New Jersey Inst Technol, Dept Phys, Newark, NJ 07102 USA. Brookhaven Natl Lab, Long Isl, NY 11973 USA. Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA. Rutgers State Univ, Dept Chem, Piscataway, NJ 08854 USA. RP New Jersey Inst Technol, Dept Phys, Newark, NJ 07102 USA. NR 33 TC 17 Z9 18 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 NOV 15 PY 2000 VL 62 IS 20 BP 13472 EP 13481 DI 10.1103/PhysRevB.62.13472 PG 10 WC Physics, Condensed Matter SC Physics GA 377ZM UT WOS:000165556400029 ER PT J AU Hart, GLW Zunger, A AF Hart, GLW Zunger, A TI Electronic structure of BAs and boride III-V alloys SO PHYSICAL REVIEW B LA English DT Article ID ABSORPTION FINE-STRUCTURE; SPECIAL QUASIRANDOM STRUCTURES; VALENCE-BAND DISCONTINUITY; RANDOM SOLID-SOLUTIONS; GALLIUM-ARSENIDE; SEMICONDUCTOR ALLOYS; BORON ARSENIDE; SPECIAL POINTS; D-ORBITALS; GAAS AB Boron arsenide, the typically ignored member of the Group-m-V arsenide series BAs-AlAs-GaAs-InAs is found to resemble silicon electronically: its Gamma conduction-band minimum is p-like (Gamma (15)), not a-like (Gamma (1c)), it has an X-1c-like indirect band gap, and its bond charge is distributed almost equally an the two atoms in the unit cell, exhibiting nearly perfect covalency. The reasons for these are trucked down to the anomalously low atomic p orbital energy in the boron and to the unusually strong s-s repulsion in BAs relative to most other Group-III-V compounds. We find unexpected valence-band offsets of BAs with respect to GaAs and AlAs. The valence-band maximum (VBM) of BAs is significantly higher than that of AlAs, despite the much smaller bond length of BAs, and the VBM of GaAs is only slightly higher than in BAs. These effects result from the unusually strong mixing of the cation and anion states at the VBM. For the BAs-GaAs alloys, we find (i) a relatively small (similar to3.5 eV) and composition-independent band-gap bowing. This means that while addition of small amounts of nitrogen to GaAs lowers the gap, addition of small amounts of boron to GaAs raises the gap; (ii) boron "semilocalized" states in the conduction band (similar to those in GaN-GaAs alloys); and (iii) bulk mixing enthalpies that are smaller than in GaN-GaAs alloys. The unique features of boride Group-III-V alloys offer new opportunities in band-gap engineering. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Zunger, Alex/A-6733-2013; OI Hart, Gus L. W./0000-0002-6149-9234 NR 73 TC 56 Z9 58 U1 0 U2 25 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 NOV 15 PY 2000 VL 62 IS 20 BP 13522 EP 13537 DI 10.1103/PhysRevB.62.13522 PG 16 WC Physics, Condensed Matter SC Physics GA 377ZM UT WOS:000165556400034 ER PT J AU Lyo, SK AF Lyo, SK TI Energy transfer of excitons between quantum wells separated by a wide barrier SO PHYSICAL REVIEW B LA English DT Article ID HETEROSTRUCTURES; ALXGA1-XAS AB We present a microscopic theory of the excitonic Stokes and anti-Stokes energy-transfer mechanisms between two widely separated unequal quantum wells with a large energy mismatch (Delta) at low temperatures (T). Several important intrinsic energy-transfer mechanisms have been examined, including dipolar coupling, real and virtual photon-exchange coupling, and over-barrier ionization of the excitons via exciton-exciton Auger processes. The transfer rate is calculated as a function of T and the center-to-center distance d between the wells. The rates depend sensitively on T for plane-wave excitons. For localized excitons, the rates depend on T only through the T dependence of the exciton localization radius. For Stokes energy transfer, the dominant energy transfer occurs through a photon-exchange interaction, which enables the excitons from the higher-energy wells to decay into free electrons and holes in the lower:energy wells. The rate has a slow dependence on d, yielding reasonable agreement with recent data from GaAs/AlxGa1-xAs quantum wells. The dipolar rate is about an order of magnitude smaller for large d (e.g., d= 175 Angstrom) with a stronger range dependence proportional to d(-4). However, the latter can be comparable to the radiative rate for small d (e.g., d less than or equal to 80 Angstrom). For anti-Stokes transfer through exchange-type (e.g., dipolar and photon-exchange) interactions, we show that thermal activation proportional to exp(-Delta /k(B) T) is essential for the transfer, contradicting a recent nonactivated result based on the Forster-Dexter's spectral-overlap theory. Phonon-assisted transfer yields a negligibly small rate. On the other hand, energy transfer through over-barrier ionization of excitons via Auger processes yields a significantly larger nonactivated rate which is independent of d. The result is compared with recent data. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 24 TC 31 Z9 32 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 NOV 15 PY 2000 VL 62 IS 20 BP 13641 EP 13656 DI 10.1103/PhysRevB.62.13641 PG 16 WC Physics, Condensed Matter SC Physics GA 377ZM UT WOS:000165556400051 ER PT J AU Arkani-Hamed, N Hall, L Smith, D Weiner, N AF Arkani-Hamed, N Hall, L Smith, D Weiner, N TI Solving the hierarchy problem with exponentially large dimensions SO PHYSICAL REVIEW D LA English DT Article ID 3-BRANE UNIVERSE; COMPACTIFICATION; SUPERSTRINGS; CONSTRAINTS; MILLIMETER; GRAVITY; TEV AB In theories with (sets of) two large extra dimensions and supersymmetry in the bulk, the presence of non-supersysmetric brane defects naturally induces a logarithmic potential for the volume of the transverse dimensions. Since the logarithm of the volume rather than the volume itself is the natural variable, parameters of O(10) in the potential can generate an exponentially large size for the extra dimensions. This provides a true solution to the hierarchy problem, on the same footing as technicolor or dynamical supersymmetry breaking. The area moduli have a Compton wavelength of about a millimeter and mediate Yukawa interactions with gravitational strength. We present a simple explicit example of this idea which generates two exponentially large dimensions. In this model, the area modulus mass is in the millimeter range even for six dimensional Planck scales as high as 100 TeV. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94530 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theory Grp, Berkeley, CA 94530 USA. RP Arkani-Hamed, N (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94530 USA. NR 22 TC 44 Z9 44 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD NOV 15 PY 2000 VL 62 IS 10 AR 105002 DI 10.1103/PhysRevD.62.105002 PG 7 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 374JG UT WOS:000165341600060 ER PT J AU Bassett, BA Liberati, S Molina-Paris, C Visser, M AF Bassett, BA Liberati, S Molina-Paris, C Visser, M TI Geometrodynamics of variable-speed-of-light cosmologies SO PHYSICAL REVIEW D LA English DT Article ID BLACK-HOLE EVAPORATION; FINE-STRUCTURE CONSTANT; FLATNESS PROBLEMS; TIME-VARIATION; LORENTZ INVARIANCE; PARALLEL MIRRORS; QUANTUM-GRAVITY; STANDARD MODEL; POWER SPECTRUM; QED VACUUM AB Variable-speed-of-light (VSL) cosmologies are currently attracting interest as an alternative to inflation. We investigate the fundamental geometrodynamic aspects of VSL cosmologies and provide several implementations which do not explicitly break Lorentz invariance (no "hard'' breaking). These ''soft'' implementations of Lorentz symmetry breaking provide particularly clean answers to the question "VSL with respect to what?." The class of VSL cosmologies,vr consider are compatible with both classical Einstein gravity and low-energy particle physics. These models solve the "kinematic" puzzles of cosmology as well as inflation does, but cannot by themselves solve the flatness problem, since in their purest form no violation of the strong energy condition occurs. We also consider a heterotic model (VSL plus inflation) which provides a number of observational implications for the low-redshift universe if chi contributes to the ''dark energy" either as CDM or quintessence. These implications include modified gravitational lensing, birefringence, variation of fundamental constants and rotation of the plane of polarization of light from distant sources. C1 Univ Portsmouth, Div Math & Stat, Relat & Cosmol Grp, Portsmouth PO1 2EG, Hants, England. Univ Oxford, Dept Theoret Phys, Oxford OX1 3NP, England. SISSA, I-34014 Trieste, Italy. Ist Nazl Fis Nucl, Sez Trieste, Trieste, Italy. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Washington Univ, Dept Phys, St Louis, MO 63130 USA. INTA, Ctr Astrobiol, Madrid 28850, Spain. RP Bassett, BA (reprint author), Univ Portsmouth, Div Math & Stat, Relat & Cosmol Grp, Portsmouth PO1 2EG, Hants, England. EM bruce.bassett@port.ac.uk; liberati@sissa.it; carmen@t6-sarv.lanl.gov; visser@kiwi.wustl.edu OI Liberati, Stefano/0000-0002-7632-7443 NR 93 TC 54 Z9 54 U1 1 U2 4 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 NOV 15 PY 2000 VL 62 IS 10 AR 103518 DI 10.1103/PhysRevD.62.103518 PG 18 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 374JG UT WOS:000165341600030 ER PT J AU Itakura, K Maedan, S AF Itakura, K Maedan, S TI Dynamical chiral symmetry breaking on the light front. II. The Nambu-Jona-Lasinio model SO PHYSICAL REVIEW D LA English DT Article ID (1+1)-DIMENSIONAL PHI(4) THEORY; ONE TIME DIMENSION; FIELD-THEORY; CONE QUANTIZATION; NULL-PLANE; ONE SPACE; QCD; QUARKS AB An investigation of dynamical chiral symmetry breaking on the light front is made in the Nambu-Jona-Lasinio model with one flavor and N colors. The analysis of the model suffers from extraordinary complexity due to the existence of a "fermionic constraint," i.e., a constraint equation for the bad spinor component. However, to solve this constraint is of special importance. In classical theory, we can exactly solve it and then explicitly check the property of "light-front chiral transformation." In quantum theory, we introduce a bilocal formulation to solve the fermionic constraint by the 1/N expansion. Systematic 1/N expansion of the fermion bilocal operator is realized by the boson expansion method. The leading (bilocal) fermionic constraint becomes a gap equation for a chiral condensate and thus if we choose a nontrivial solution of the gap equation, we are in the broken phase. As a result of the nonzero chiral condensate, we find an unusual chiral transformation of fields and nonvanishing of the light-front chiral charge. A leading-order eigenvalue equation for a single bosonic state is equivalent to a leading-order fermion-antifermion bound-state equation. We analytically solve it for scalar and pseudoscalar mesons and obtain their light-cone wave functions and masses. All of the results are entirely consistent with those of our previous analysis on the chiral Yukawa model. C1 Osaka Univ, Nucl Phys Res Ctr, Osaka 5670047, Japan. Tokyo Natl Coll Technol, Dept Phys, Tokyo 1938610, Japan. RP Itakura, K (reprint author), Brookhaven Natl Lab, RIKEN BNL Res Ctr, Upton, NY 11973 USA. EM itakura@bnl.gov; maedan@tokyo-ct.ac.jp NR 34 TC 1 Z9 1 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD NOV 15 PY 2000 VL 62 IS 10 AR 105016 PG 19 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 374JG UT WOS:000165341600074 ER PT J AU Shmakova, M AF Shmakova, M TI One-loop corrections to the D3-brane action SO PHYSICAL REVIEW D LA English DT Article ID GAUGE-THEORIES; YANG-MILLS; D-BRANES; AMPLITUDES; BREMSSTRAHLUNG; SUPERSYMMETRY; FINITENESS; SUPERSPACE AB We calculate one-loop corrections to the effective Lagrangian for the D3-brane. We perform the gauge fixing of the K-symmetric Born-Infeld D3-brane action in the flat background using the Killing gauge. The linearized supersymmetry of the gauge-fixed action coincides with that of the N = 4 Yang-Mills theory. We use the helicity amplitude and unitarity technique to calculate the one-loop amplitudes at order alpha (4). The counterterms and the finite 1-loop corrections are of the form (partial derivativeF)(4) and their supersymmetric generalization. This is to be contrasted with the Born-Infeld action which contains (F)(4) and other terms which do not depend on derivatives of the vector field strength. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Calif Inst Phys & Astrophys, Palo Alto, CA 94306 USA. RP Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. EM shmakova@slac.stanford.edu NR 43 TC 3 Z9 3 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD NOV 15 PY 2000 VL 62 IS 10 AR 104009 DI 10.1103/PhysRevD.62.104009 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 374JG UT WOS:000165341600042 ER PT J AU Dale, VH Joyce, LA McNulty, S Neilson, RP AF Dale, VH Joyce, LA McNulty, S Neilson, RP TI The interplay between climate change, forests, and disturbances SO SCIENCE OF THE TOTAL ENVIRONMENT LA English DT Article DE drought; fire; hurricanes; introduced species; outbreaks; storms AB Climate change affects forests both directly and indirectly through disturbances. Disturbances are a natural and integral part of forest ecosystems, and climate change can alter these natural interactions. When disturbances exceed their natural range of variation, the change in forest structure and function may be extreme. Each disturbance affects forests differently. Some disturbances have tight interactions with the species and forest communities which can be disrupted by climate change. Impacts of disturbances and thus of climate change are seen over a board spectrum of spatial and temporal scales. Future observations, research, and tool development are needed to further understand the interactions between climate change and forest disturbances. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. USDA, Forest Serv, Ft Collins, CO 80523 USA. USDA, Forest Serv, Raleigh, NC 27606 USA. US Forest Serv, Pacific NW Res Stn, Corvallis, OR 97331 USA. RP Dale, VH (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. RI Neilson, Ronald/A-8588-2009; Dale, Virginia/B-6023-2009 NR 8 TC 90 Z9 95 U1 5 U2 38 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0048-9697 J9 SCI TOTAL ENVIRON JI Sci. Total Environ. PD NOV 15 PY 2000 VL 262 IS 3 BP 201 EP 204 DI 10.1016/S0048-9697(00)00522-2 PG 4 WC Environmental Sciences SC Environmental Sciences & Ecology GA 369KQ UT WOS:000165064800001 PM 11087026 ER PT J AU Hanson, PJ Weltzin, JF AF Hanson, PJ Weltzin, JF TI Drought disturbance from climate change: response of United States forests SO SCIENCE OF THE TOTAL ENVIRONMENT LA English DT Review DE forest; drought; climate change; precipitation ID EASTERN NORTH-AMERICA; UPLAND OAK FOREST; WATER RELATIONS; ATMOSPHERIC CO2; VEGETATION DISTRIBUTION; SUMMER PRECIPITATION; ENVIRONMENTAL-STRESS; PLANT-COMMUNITIES; CONTINENTAL-SCALE; LOBLOLLY-PINE AB Predicted changes in climate have raised concerns about potential impacts on terrestrial forest ecosystem productivity, biogeochemical cycling, and the availability of water resources. This review summarizes characteristics of drought typical to the major forest regions of the United States, future drought projections, and important features of plant and forest community response to drought. Research needs and strategies for coping with future drought are also discussed. Notwithstanding uncertainties surrounding the magnitude and direction of future climate change, and the net impact on soil water availability to forests, a number of conclusions can be made regarding the sensitivity of forests to future drought. The primary response will be a reduction in net primary production and stand water use, which are driven by reductions in stomatal conductance. Mortality of small stature plants (i.e. seedlings and saplings) is a likely consequence of severe drought. In comparison, deep rooting and substantial reserves of carbohydrates and nutrients make mature trees less susceptible to water limitations caused by severe or prolonged drought. However, severe or prolonged drought may render even mature trees more susceptible to insects or disease. Drought-induced reductions in decomposition rates may cause a buildup of organic material on the forest floor, with ramifications for fire regimes and nutrient cycling. Although early model predictions of climate change impacts suggested extensive forest dieback and species migration, more recent analyses suggest that catastrophic dieback will be a local phenomenon, and changes in forest composition will be a relatively gradual process. Better climate predictions at regional scales, with a higher temporal resolution (months to days), coupled with carefully designed, field-based experiments that incorporate multiple driving variables (e.g. temperature and CO2), will advance our ability to predict the response of different forest regions to climate change. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Tennessee, Knoxville, TN 37996 USA. RP Hanson, PJ (reprint author), Oak Ridge Natl Lab, POB 2008,Bethel Valley Rd,Bldg 1059, Oak Ridge, TN 37831 USA. RI Hanson, Paul J./D-8069-2011 OI Hanson, Paul J./0000-0001-7293-3561 NR 125 TC 185 Z9 196 U1 18 U2 129 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0048-9697 J9 SCI TOTAL ENVIRON JI Sci. Total Environ. PD NOV 15 PY 2000 VL 262 IS 3 BP 205 EP 220 DI 10.1016/S0048-9697(00)00523-4 PG 16 WC Environmental Sciences SC Environmental Sciences & Ecology GA 369KQ UT WOS:000165064800002 PM 11087027 ER PT J AU Jin, Z Su, YX Duan, YX AF Jin, Z Su, YX Duan, YX TI An improved optical pH sensor based on polyaniline SO SENSORS AND ACTUATORS B-CHEMICAL LA English DT Article DE optical fiber; sensor; pH; polyaniline ID FILMS AB An optical pH sensor based on polyaniline is presented in this paper. Polyaniline films were prepared by chemical oxidation at room temperature. By increasing reaction time for up to 12 h, the stability of the polyaniline film was significantly improved. The film showed rapid reversible color change upon pH change. Solution pH could be determined by monitoring either absorption at a fixed wavelength or the maximum absorption wavelength of the film. The optical pH sensors can be exposed in air for over 1 month without any deterioration in sensor performance. Published by Elsevier Science B.V. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Duan, YX (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, CST-9,MS K484, Los Alamos, NM 87545 USA. NR 15 TC 119 Z9 124 U1 3 U2 26 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-4005 J9 SENSOR ACTUAT B-CHEM JI Sens. Actuator B-Chem. PD NOV 15 PY 2000 VL 71 IS 1-2 BP 118 EP 122 DI 10.1016/S0925-4005(00)00597-9 PG 5 WC Chemistry, Analytical; Electrochemistry; Instruments & Instrumentation SC Chemistry; Electrochemistry; Instruments & Instrumentation GA 380MU UT WOS:000165706300020 ER PT J AU Devedjiev, Y Dauter, Z Kuznetsov, SR Jones, TLZ Derewenda, ZS AF Devedjiev, Y Dauter, Z Kuznetsov, SR Jones, TLZ Derewenda, ZS TI Crystal structure of the human acyl protein thioesterase I from a single X-ray data set to 1.5 angstrom SO STRUCTURE LA English DT Article DE alpha/beta hydrolase; serine hydrolase; SAD; anomalous diffraction ID NEURONAL CEROID-LIPOFUSCINOSIS; ALPHA-SUBUNITS; LIPID MODIFICATIONS; PLASMA-MEMBRANE; PALMITOYLATION; ACTIVATION; RECEPTOR; LYSOPHOSPHOLIPASE; CRYSTALLOGRAPHY; PURIFICATION AB Background: Many proteins undergo posttranslational modifications involving covalent attachment of lipid groups. Among them is palmitoylation, a dynamic, reversible process that affects trimeric G proteins and Ras and constitutes a regulatory mechanism for signal transduction pathways. Recently, an acylhydrolase previously identified as lysophospholipase has been shown to function as an acyl protein thioesterase, which catalyzes depalmitoylation of Got proteins as well as Ras. Its amino acid sequence suggested that the protein is evolutionarily related to neutral lipases and other thioesterases, but direct structural information was not available. Results: We have solved the crystal structure of the human putative Ga-regulatory protein acyl thioesterase (hAPT1) with a single data set collected from a crystal containing the wildtype protein. The phases were calculated to 1.8 Angstrom resolution based on anomalous scattering from Br- ions introduced in the cryoprotectant solution in which the crystal was soaked for 20 s. The model was refined against data extending to a resolution of 1.5 Angstrom to an R factor of 18.6%. The enzyme is a member of the ubiquitous alpha/beta hydrolase family, which includes other acylhydrolases such as the palmitoyl protein thioesterase (PPT1). Conclusions: The human APT1 is closely related to a previously described carboxylesterase from Pseudomonas fluorescens. The active site contains a catalytic triad of Ser-114, His-203, and Asp-169. Like carboxylesterase, hAPT1 appears to be dimeric, although the mutual disposition of molecules in the two dimers differs. Unlike carboxylesterase, the substrate binding pocket and the active site of hAPT1 are occluded by the dimer interface, suggesting that the enzyme must dissociate upon interaction with substrate. C1 Univ Virginia, Hlth Sci Syst, Dept Mol Physiol & Biol Phys, Charlottesville, VA 22908 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. NCI, Frederick, MD 21701 USA. NIDDKD, Metab Dis Branch, NIH, Bethesda, MD 20892 USA. RP Derewenda, ZS (reprint author), Univ Virginia, Hlth Sci Syst, Dept Mol Physiol & Biol Phys, Charlottesville, VA 22908 USA. FU NHLBI NIH HHS [HL48807] NR 49 TC 81 Z9 82 U1 1 U2 8 PU CELL PRESS PI CAMBRIDGE PA 1100 MASSACHUSETTES AVE,, CAMBRIDGE, MA 02138 USA SN 0969-2126 J9 STRUCTURE JI Structure PD NOV 15 PY 2000 VL 8 IS 11 BP 1137 EP 1146 DI 10.1016/S0969-2126(00)00529-3 PG 10 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 420TX UT WOS:000168022300006 PM 11080636 ER PT J AU Fournier, KB Bauche, J Bauche-Arnoult, C AF Fournier, KB Bauche, J Bauche-Arnoult, C TI Evidence for a temperature law in non-LTE hot plasmas SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID SPECTRA AB Following a recent paper (Bauche J and Bauche-Amoult C 2000 J. Phys. B: At. Mel. Opt. Phys. 33 L283), we investigate numerically the relation between the populations in the levels of an ionic configuration and individual level energies. It is found that for densities far from those for which local thermodynamic equilibrium is obtained, level populations still obey a decreasing exponential law for an effective temperature within the configuration. We begin by demonstrating the linear relationship between the collision-strength-weighted mean energies of the levels of a configuration and the energies of the final levels to which they are coupled. This linear relationship means that if the populations in the levels of the initial configuration are described by a distribution characterized by some temperature, then the populations in the levels of the final configuration are also characterized by the same distribution with a related temperature. We then look at the populations in the levels of the 3d(4) and 3d(3)4p configurations of Fe V and Kr XV. We compute the populations in all levels of a large, detailed collisional-radiative model that involves nine configurations, then derive the effective temperatures for 3d(4) and 3d(3)4p by fitting a line to the calculated level populations. We look at the cases of Fe V by itself and for Fe V coupled to equally detailed models of Fe rv and Fe vr, and similarly for Kr XV coupled to Kr XIV and Kr XVI. Finally, the effect of a Planckian radiation field on the level populations is considered. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Lab Aimee Cotton, F-91405 Orsay, France. RP Fournier, KB (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 11 TC 16 Z9 16 U1 0 U2 1 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 NOV 14 PY 2000 VL 33 IS 21 BP 4891 EP 4904 DI 10.1088/0953-4075/33/21/329 PG 14 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 379WM UT WOS:000165666200036 ER PT J AU Hovenier, JN de Kleijn, RM Klaassen, TO Wenckebach, WT Chamberlin, DR Brundermann, E Haller, EE AF Hovenier, JN de Kleijn, RM Klaassen, TO Wenckebach, WT Chamberlin, DR Brundermann, E Haller, EE TI Mode-locked operation of the copper-doped germanium terahertz laser SO APPLIED PHYSICS LETTERS LA English DT Article ID GE AB We have fabricated a copper-doped germanium laser using copper diffusion into commercially available pure germanium. The spectrum and the emission pulses of this laser were investigated. Active mode locking was achieved with pulse lengths of 160 ps at full width half maximum. The current Ge:Cu laser does not yet reach the performance of an earlier studied Ge:Ga laser although mode-locked Ge:Cu lasers promise much shorter pulse lengths and wavelength tunable pulses due to the absence of acceptor related absorption. Possibilities to optimize the laser will be discussed. (C) 2000 American Institute of Physics. [S0003-6951(00)05346-8]. C1 Delft Univ Technol, Dept Appl Phys, NL-2600 GA Delft, Netherlands. Delft Univ Technol, Delft Inst Microelect & Submicron Technol, NL-2600 GA Delft, Netherlands. Univ Calif Berkeley, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Hovenier, JN (reprint author), Delft Univ Technol, Dept Appl Phys, POB 5046, NL-2600 GA Delft, Netherlands. RI Bruendermann, Erik/J-7186-2016 OI Bruendermann, Erik/0000-0003-4119-3489 NR 8 TC 8 Z9 8 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD NOV 13 PY 2000 VL 77 IS 20 BP 3155 EP 3157 AR PII [S0003-6951(00)05346-8] DI 10.1063/1.1326487 PG 3 WC Physics, Applied SC Physics GA 371FJ UT WOS:000165167600009 ER PT J AU Ashby, CIH Mitchell, CC Han, J Missert, NA Provencio, PP Follstaedt, DM Peake, GM Griego, L AF Ashby, CIH Mitchell, CC Han, J Missert, NA Provencio, PP Follstaedt, DM Peake, GM Griego, L TI Low-dislocation-density GaN from a single growth on a textured substrate SO APPLIED PHYSICS LETTERS LA English DT Article ID CHEMICAL-VAPOR-DEPOSITION; LATERAL EPITAXY; REDUCTION; OVERGROWTH; MECHANISMS; AREA AB The density of threading dislocations (TD) in GaN grown directly on flat sapphire substrates is typically greater than 10(9)/cm(2). The density of dislocations can be decreased by orders of magnitude using cantilever epitaxy, which employs pre-patterned sapphire substrates to provide reduced-dimension mesa regions for nucleation and etched trenches between them for suspended lateral growth of GaN or AlGaN. The substrate is pre-patterned with narrow lines and etched to a depth that permits coalescence of laterally growing III-N nucleated on the mesa surfaces before vertical growth fills the etched trench. Low-dislocation densities typical of epitaxial lateral overgrowth are obtained in the cantilever regions and the TD density is also reduced up to 1 mum from the edge of the support regions. (C) 2000 American Institute of Physics. [S0003-6951(00)02846-1]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Ashby, CIH (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 15 TC 129 Z9 134 U1 3 U2 36 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD NOV 13 PY 2000 VL 77 IS 20 BP 3233 EP 3235 DI 10.1063/1.1325394 PG 3 WC Physics, Applied SC Physics GA 371FJ UT WOS:000165167600035 ER PT J AU Carlson, CM Parilla, PA Rivkin, TV Perkins, JD Ginley, DS AF Carlson, CM Parilla, PA Rivkin, TV Perkins, JD Ginley, DS TI Control and elimination of biaxial strain in laser-ablated epitaxial BaxSr1-xTiO3 films SO APPLIED PHYSICS LETTERS LA English DT Article ID BATIO3 THIN-FILMS; SURFACE-MORPHOLOGY; INTERNAL-STRESSES; GROWTH; SRTIO3 AB We report the in-plane (a) and out-of-plane (c) lattice parameters of epitaxial laser-ablated Ba0.4Sr0.6TiO3 films on MgO for a range of O-2 deposition pressures (40-250 mTorr) near the observed transition from a c. From these lattice parameters, we calculate the residual strain and stress in terms of hydrostatic and biaxial components. Both components increase sharply with O-2 pressure between 85 and 100 mTorr, consistent with ion peening effects. Postdeposition annealing decreases the hydrostatic strain, but increases the biaxial tension. For both as-deposited and annealed films, we obtain samples with no biaxial strain (i.e., a=c), within experimental uncertainty. Overall, the strain is a combination of hydrostatic and biaxial components, both of which affect the dielectric response. Therefore, consideration and control of both types of strain is important for the optimum performance of devices such as tunable microwave devices and high-density memories. (C) 2000 American Institute of Physics. [S0003-6951(00)01533-3]. C1 Univ Colorado, Dept Phys, Boulder, CO 80309 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Carlson, CM (reprint author), Univ Colorado, Dept Phys, Boulder, CO 80309 USA. NR 15 TC 27 Z9 27 U1 1 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD NOV 13 PY 2000 VL 77 IS 20 BP 3278 EP 3280 DI 10.1063/1.1288808 PG 3 WC Physics, Applied SC Physics GA 371FJ UT WOS:000165167600050 ER PT J AU Muller, A Beugholt, C Kogerler, P Bogge, H Bud'ko, S Luban, M AF Muller, A Beugholt, C Kogerler, P Bogge, H Bud'ko, S Luban, M TI [(Mo12O30)-O-V(mu(2)-OH)(10)H-2{Ni-II(H2O)3}4], a highly symmetrical epsilon-Keggin unit capped with four Ni-II centers: Synthesis and magnetism SO INORGANIC CHEMISTRY LA English DT Article ID CLUSTERS; NUCLEARITY; COMPLEXES AB The novel title compound {(Ni4Mo12v)-Mo-II} demonstrates the concept of generating targeted spin topologies using reduced polyoxometalates: The four electrophilic nickel centers-forming a tetrahedron-are fixed by a nucleophilic highly reduced diamagnetic epsilon -Keggin cluster of T-d symmetry generated in solution. This cluster not only has a structural role but actually participates in the transmission of the exchange interaction. C1 Univ Bielefeld, Fak Chem, Lehrstuhl Anorgan Chem 1, D-33501 Bielefeld, Germany. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Muller, A (reprint author), Univ Bielefeld, Fak Chem, Lehrstuhl Anorgan Chem 1, Postfach 100131, D-33501 Bielefeld, Germany. RI Kogerler, Paul/H-5866-2013; OI Kogerler, Paul/0000-0001-7831-3953; Muller, Achim/0000-0003-0117-4021 NR 15 TC 67 Z9 67 U1 0 U2 8 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 NOV 13 PY 2000 VL 39 IS 23 BP 5176 EP + DI 10.1021/ic0005285 PG 3 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 375EJ UT WOS:000165386300002 PM 11187464 ER PT J AU Corbett, JD AF Corbett, JD TI Exploratory synthesis in the solid state. Endless wonders SO INORGANIC CHEMISTRY LA English DT Article; Proceedings Paper CT 219th National Meeting of the American-Chemical-Society CY MAR 26-30, 2000 CL SAN FRANCISCO, CALIFORNIA SP Amer Chem Soc ID METALLIC ZINTL PHASE; RARE-EARTH-METALS; ZIRCONIUM CHLORIDE CLUSTERS; TRANSITION-METALS; INTERSTITIAL COMPOUNDS; CRYSTAL-STRUCTURES; IODIDE CLUSTERS; HALIDE CLUSTERS; CHAIN COMPOUNDS; INDIUM CLUSTER AB This article gives an overview of recent developments in three areas of solid state chemistry: (1) The discovery that centered and originally-adventitious interstitial elements Z are essential for the stability of M6X12-type cluster halides of group 3 and 4 metals has led to a large amount of new chemistry through tuning structures and compositions of A(n)M(6)(Z)X12Xn phases with the variables Z, x, and it. The corresponding metal-rich group 3 tellurides exhibit novel and more extensive metal aggregation, reflecting a decreased number of anions and valence electrons. (2) Many intrinsically metallic T5M3 phases with a Mn5Si3-type structure are formed by early transition metals T with main-group elements M. Each characteristically reacts with diverse elements (up to 15-20 each) to form stuffed interstitial versions T(5)M(3)Z Of the same structure. The ranges of Z and some properties are described. Related reactions of hydrogen (often as an impurity) in Mn5Si3-, beta -Yb5Sb3-, and Cr5B3-type systems are extensive. Substantially all previous reports of beta -Yb5Sb3- and Cr5B3-type phases for divalent metals with pnictogen (As-Bi) and tetrel (Si-Pb) elements, respectively, have been for the hydrides, and about two-thirds do not exist without that hydrogen (or fluorine). (3) The developing chemistry of anionic polymetal cluster compounds of the main-group elements with alkali-metal cations is outlined, particularly for the triel elements In and Tl. These clusters lie to the left of what has been called the Zintl boundary, many are new hypoelectronic polyhedra, some may be centered by the same or another neighboring element, and so far all have been isolated only as neat solid state compounds in which specificity of cation-anion interactions seems important. Extended networks are also encountered. C1 Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Corbett, JD (reprint author), Iowa State Univ, Dept Chem, Ames, IA 50011 USA. NR 92 TC 105 Z9 106 U1 2 U2 26 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 NOV 13 PY 2000 VL 39 IS 23 BP 5178 EP 5191 DI 10.1021/ic0007862 PG 14 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 375EJ UT WOS:000165386300003 PM 11154578 ER PT J AU Musgrave, KB Lim, BS Sung, KM Holm, RH Hedman, B Hodgson, KO AF Musgrave, KB Lim, BS Sung, KM Holm, RH Hedman, B Hodgson, KO TI X-ray spectroscopy of enzyme active site analogues and related molecules: Bis(dithiolene)molybdenum(IV) and -tungsten(IV,VI) complexes with variant terminal ligands SO INORGANIC CHEMISTRY LA English DT Article ID DIMETHYL-SULFOXIDE REDUCTASE; RESOLUTION CRYSTAL-STRUCTURE; ABSORPTION-SPECTROSCOPY; DMSO REDUCTASE; FERREDOXIN OXIDOREDUCTASE; RHODOBACTER-CAPSULATUS; FORMATE DEHYDROGENASE; MOLYBDENUM SITE; MOLYBDOPTERIN; REACTIVITY AB The X-ray absorption spectra at the molybdenum and selenium K-edges and the tungsten L-2,L-3-edges are acquired for a set of 14 Mo(IV) and W(IV,VI) bis(dithiolene) complexes related to the active sites of molybdo- and tungstoenzymes. The set includes square pyramidal [(MoL)-L-IV(S2C2Me2)(2)](-) (L = O2-, R3SiO-, RO-, RS-, RSe-) and [W-IV(OR)(S2C2Me2)(2)](-), distorted trigonal prismatic [Mo-IV(CO)(SeR)(S2C2Me2)(2)](-) and [W-IV(CO)L(S2C2Me2)(2)](-) (L = RS-, RSe-), and distorted octahedral [(WO)-O-VI(OR)(S2C2Me2)(2)](-). The dithiolene simulates the pterin-dithiolene cofactor ligand, and L represents a protein ligand. Bond lengths are determined by EXAFS analysis using the GNXAS protocol. Normalized edge spectra, non-phase-shift-corrected Fourier transforms, and EXAFS data and fits are presented. Bond lengths determined by EXAFS and X-ray crystallography agree to less than or equal to0.02 Angstrom as do the M-Se distances determined by both metal and selenium EXAFS. The complexes [Mo-IV(QR)(S2C2Me2)(2)](-) simulate protein Ligation by the DMSO reductase family of enzymes, including DMSO reductase itself (Q = O), dissimilatory nitrate reductase (Q = S), and formate dehydrogenase (Q = Se). Edge shifts of these complexes correlate with the ligand electronegativities. Terminal Ligand binding is clearly distinguished in the presence of four Mo-S(dithiolene) interactions. Similarly, five-coordinate [ML(S2C2Me2)(2)](-) and six-coordinate [M(CO)L(S2C2Me2)(2)](-)are distinguishable by edge and EXAFS spectra. This study expands a previous XAS investigation of bis(dithiolene)-metal(IV,V,VI) complexes (Musgrave, K. B.; Donahue, J. P.; Lorber, C.; Holm, R. Fl.; Hedman, B.; Hodgson, K. O. J. Am. Chem. Sec. 1999, 121, 10297) by including a larger inventory of molecules with variant physiologically relevant terminal ligation. The previous and present XAS results should prove useful in characterizing and refining metric features and structures of enzyme sites. C1 Stanford Univ, Dept Chem, Stanford, CA 94305 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. Harvard Univ, Dept Chem & Chem Biol, Cambridge, MA 02138 USA. RP Holm, RH (reprint author), Stanford Univ, Dept Chem, Stanford, CA 94305 USA. FU NCRR NIH HHS [RR-01209] NR 33 TC 23 Z9 23 U1 1 U2 11 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 NOV 13 PY 2000 VL 39 IS 23 BP 5238 EP 5247 DI 10.1021/ic000601r PG 10 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 375EJ UT WOS:000165386300011 PM 11154582 ER PT J AU Wilkerson, MP Burns, CJ Dewey, HJ Martin, JM Morris, DE Paine, RT Scott, BL AF Wilkerson, MP Burns, CJ Dewey, HJ Martin, JM Morris, DE Paine, RT Scott, BL TI Basicity of uranyl oxo ligands upon coordination of alkoxides SO INORGANIC CHEMISTRY LA English DT Article ID OXYGEN-ATOM TRANSFER; VALENT ORGANOURANIUM COMPLEXES; NUCLEOPHILE TRANSFER-REACTIONS; LASER-INDUCED FLUORESCENCE; ELECTRONIC-STRUCTURE; CRYSTAL-STRUCTURE; CYCLOADDITION REACTIONS; URANIUM SPECIATION; FUNCTIONAL-GROUPS; MULTIPLE BONDS AB Uranium(VI) alkoxide complexes are prepared via metathesis reactions of [UO2Cl2(THF)(2)](2) with potassium alkoxides in nonaqueous media. The dark red compound U[OCH2C(CH3)(3)](6), 1, results from redistributive exchange of oxo and neopentoxide Ligands between more than one uranium species. Single-crystal X-ray diffraction analysis of 1 reveals a monomer in which the uranium is coordinated in a pseudooctahedral fashion by six neopentoxide ligands. Imposition of steric congestion at the metal center prevents oxo-alkoxide ligand exchange in the reactions using more sterically demanding alkoxides. Simple metathesis between uranyl chloride and alkoxide ligands occurs in the synthesis of golden yellow-orange UO2(OCHPh2)(2)(THF)(2), 2, and yellow UO2[OCH(Bu-t)Ph](2)(THF)(2), 3. Single-crystal X-ray diffraction analysis of 2 reveals a monomer in which the uranium is coordinated in a pseudooctahedral fashion by two apical oxo ligands, two diphenylmethoxide ligands occupying trans positions, and two tetrahydrofuran ligands. Coordination of diisopropylmethoxide allows for synthesis of a more complex binary alkoxide system. Single-crystal X-ray diffraction analysis of watermelon red [UO2(OCH(Pr-i)(2))(2)](4), 4, reveals a tetramer in which each uranium is coordinated in a pseudooctahedral fashion by two apical oxo ligands, one terminal alkoxide, two bridging all;oxide ligands, and one bridging oxo ligand from a neighboring uranyl group. These compounds are characterized by elemental analysis,H-1 NMR, infrared spectroscopy, and, for 1, 2, and 4, single-crystal X-ray diffraction analysis. Luminescence spectroscopy is employed to evaluate the extent of aggregation of compounds 2-4 in various solvents. Vibrational spectroscopic measurements of 2-4 imply that, in contrast to the case of uranyl complexes prepared in aqueous environments, coordination of relatively strongly donating alkoxide ligands allows for enhancement of electron density on the uranyl groups such that the uranyl U=O bonds are weakened. Crystal data are as follows. 1: monoclinic space group C2/m, a = 10.6192(8) Angstrom, b = 18.36(1) Angstrom, c = 10.6151(8) Angstrom, beta = 109.637(1)degrees, V = 1949.1(3) Angstrom (3), Z = 2, d(calc) = 1.297 g cm(-3). Refinement of 2065 reflections gave R1 = 0.045. 2: monoclinic space group P2(1)/c, a = 6.1796(4) Angstrom, b 15.669(1) Angstrom, c = 16.169(1) Angstrom, beta = 95.380(1)degrees V = 1558.7(2) Angstrom (3), Z = 2, d(calc), 1.664 g:cm-3. Refinement of 3048 reflections gave R1 = 0.036. 4: tetragonal space group 14, a 17.8570(6) Angstrom, b = 17.8570(6) Angstrom, c = 11.4489(6) Angstrom, V = 3650.7(3) Angstrom (3), Z = 2, d(calc) = 1.821 cm(-3). Refinement of 1981 reflections gave R1 = 0.020. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Univ New Mexico, Dept Chem, Albuquerque, NM 87131 USA. RP Burns, CJ (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, POB 1663, Los Alamos, NM 87545 USA. RI Morris, David/A-8577-2012; Scott, Brian/D-8995-2017 OI Scott, Brian/0000-0003-0468-5396 NR 86 TC 62 Z9 62 U1 0 U2 21 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 NOV 13 PY 2000 VL 39 IS 23 BP 5277 EP 5285 DI 10.1021/ic000142u PG 9 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 375EJ UT WOS:000165386300016 PM 11154586 ER PT J AU Bitterwolf, TE Linehan, JC Shade, JE AF Bitterwolf, TE Linehan, JC Shade, JE TI Dihydrogen as a reactant in the photochemistry of bimetallic cyclopentadienyl carbonyl compounds SO ORGANOMETALLICS LA English DT Article ID TRIBUTYLTIN HYDRIDE; COMPLEXES; PHOTOLYSIS; MATRICES; M=CR; MO AB Dihydrogen has been found to react photochemically with bimetallic compounds oft he form [(eta (5)-C5H5)M(CO)(n)](2), where M = Mo or W, n. = 3, M = Fe or Ru, n = 2, to give the corresponding metal hydrides, (eta (5)-C5H5)M(CO)(n)H. Hydride formation is only significant when the photolysis wavelengths are in the high-energy regions known to trigger CO boss from these compounds, and hydride formation is suppressed by added CO, making if likely that the reaction involves oxidative addition of H-2 to an electron-deficient, GO-Loss intermediate. C1 Univ Idaho, Dept Chem, Moscow, ID 83844 USA. Pacific NW Natl Lab, Dept Chem Sci, Richland, WA 99352 USA. USN Acad, Dept Chem, Annapolis, MD 21402 USA. RP Bitterwolf, TE (reprint author), Univ Idaho, Dept Chem, Moscow, ID 83844 USA. NR 18 TC 10 Z9 10 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD NOV 13 PY 2000 VL 19 IS 23 BP 4915 EP 4917 DI 10.1021/om000292c PG 3 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA 375KG UT WOS:000165397800038 ER PT J AU Babansky, A Balitsky, I AF Babansky, A Balitsky, I TI Renormalons as dilatation modes in the functional space SO PHYSICAL REVIEW LETTERS LA English DT Article ID VACUUM; QCD AB There are two possible sources of the factorial large-order behavior of a typical perturbative series. First, the number of different Feynman diagrams may be large;second, there may be abnormally large diagrams known as renormalons. It is well known that the large combinatorial number of diagrams is described by instanton-type solutions of the classical equations. We demonstrate that, from the functional integral viewpoint, the renormalons do not correspond to a particular configuration but manifest themselves as dilatation modes in the functional space. C1 Old Dominion Univ, Dept Phys, Norfolk, VA 23529 USA. Jefferson Lab, Theory Grp, Newport News, VA 23606 USA. RP Babansky, A (reprint author), Old Dominion Univ, Dept Phys, Norfolk, VA 23529 USA. NR 17 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 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD NOV 13 PY 2000 VL 85 IS 20 BP 4211 EP 4214 DI 10.1103/PhysRevLett.85.4211 PG 4 WC Physics, Multidisciplinary SC Physics GA 372RK UT WOS:000165247700005 ER PT J AU Affolder, T Akimoto, H Akopian, A Albrow, MG Amaral, P Amendolia, SR Amidei, D Anikeev, K Antos, J Apollinari, G Arisawa, T Asakawa, T Ashmanskas, W Atac, M Azfar, F Azzi-Bacchetta, P Bacchetta, N Bailey, MW Bailey, S de Barbaro, P Barbaro-Galtieri, A Barnes, VE Barnett, BA Barone, M Bauer, G Bedeschi, F Belforte, S Bellettini, G Bellinger, J Benjamin, D Bensinger, J Beretvas, A Berge, JP Berryhill, J Bevensee, B Bhatti, A Binkley, M Bisello, D Blair, RE Blocker, C Bloom, K Blumenfeld, B Blusk, SR Bocci, A Borras, K Bodek, A Bokhari, W Bolla, G Bonushkin, Y Bortoletto, D Boudreau, J Bindl, A van den Brink, S Bromberg, C Brozovic, M Bruner, N Buckley-Geer, E Budagov, J Budd, HS Burkett, K Busetto, G Byon-Wagner, A Byrum, KL Calafiura, P Campbell, M Carithers, W Carlson, J Carlsmith, D Cassada, J Castro, A Cauz, D Cerri, A Chan, AW Chang, PS Chang, PT Chapman, J Chen, C Chen, YC Cheng, MT Chertok, M Chiarelli, G Chirikov-Zorin, I Chlachidze, G Chlebana, F Christofek, L Chu, RL Ciobanu, CI Clark, AG Connolly, A Convery, M Conway, J Cooper, J Cordelli, M Cranshaw, J Cronin-Hennessy, D Cropp, R Culbertson, R Dagenhart, D 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 Engels, E Erdmann, W Errede, D Errede, S Fan, Q Feild, RG Ferretti, C Field, RD Fiori, I Flaugher, B Foster, GW Franklin, M Freeman, J Friedman, J Fukui, Y Galeotti, S Gallinaro, M Gao, T Garcia-Sciveres, M Garfinkel, AF Gatti, P Gay, C Geer, S Gerdes, DW Giannetti, P Glagolev, V Gold, M Goldstein, J Gordon, A Goshaw, AT Gotra, Y Goulianos, K Green, C Groer, L Grosso-Pilcher, C Guenther, M Guillian, G da Costa, JG Guo, RS Haas, RM Haber, C Hafen, E Hahn, SR Hall, C Handa, T Handler, R Hao, W Happacher, F Hara, K Hardman, AD Harris, RM Hartmann, F Hatakeyama, K Hauser, J Heinrich, J Heiss, A Herndon, M Hinrichsen, B Hoffman, KD Holck, C Hollebeek, R Holloway, L Hughes, R Huston, J Huth, J Ikeda, H Incandela, J Introzzi, G Iwai, J Iwata, Y James, E Jensen, H Jones, M Joshi, U Kamara, H Kamon, T Kaneko, T Karr, K Kasha, H Kato, Y Keaffaber, TA Kelley, K Kelly, M Kennedy, RD Kephart, R Khazins, D Kikuchi, T Kilminster, B Kirby, M Kirk, M Kim, BJ Kim, DH Kim, HS Kim, MJ Kim, SH Kim, YK Kirsch, L Klimenko, S Koehn, P Kongeter, A Kondo, K Konigsberg, J Kordas, K Korn, A Korytov, A Kovacs, E Kroll, J Kruse, M Kuhlmann, SE Kurino, K Kuwabara, T Laasanen, AT Lai, N Lami, S Lammel, S Lamoureux, JI Lancaster, M Latino, G LeCompte, T Lee, AM Lee, K Leone, S Lewis, JD Lindgren, M Liss, TM Liu, JB Liu, YC Lockyer, N Loken, J Loreti, M Lucchesi, D Lukens, P Lusin, S Lyons, L Lys, J Madrak, R Maeshima, K Maksimovic, P Malferrari, L Mangano, M Mariotti, M Martignon, G Martin, A Matthews, JAJ Mayer, J Mazzanti, P McFarland, KS McIntyre, P McKigney, E Melese, P Menguzzato, M Menzione, A Mesropian, C Miao, T Miller, R Miller, JS Minato, H Miscetti, S Mishina, M Mitselmakher, G Moggi, N Moore, C Moore, E Moore, R Morita, Y Mukherjee, A Muller, T Munar, A Murat, P Murgia, S Musy, M Nachtman, J Nahn, S Nakada, H Nakaya, T Nakano, I Nelson, C Neuberger, D Newman-Holmes, C Ngan, CYP Nicolaidi, P Niu, H Nodulman, L Nomerotski, A Oh, SH Ohmoto, T Ohsugi, T Oishi, R Okusawa, T Olsen, J Orejudos, W Pagliarone, C Palmonari, F Paoletti, R Papadimitriou, V Pappas, SP Partos, D Patrick, J Pauletta, G Paulini, M Paus, C Pescara, L Phillips, TJ Piacentino, G Pitts, KT Plunkett, R Pompos, A Pondrom, L Pope, G Popovic, M Prokoshin, F Proudfoot, J Ptohos, F Pukhov, O Punzi, G Ragan, K Rakitine, A Reher, D Reichold, A Riegler, W Ribon, A Rimondi, F Ristori, L Robertson, WJ Robinson, A Rodrigo, T Rolli, S Rosenson, L Roser, R Rossin, R Sakumoto, WK Saltzberg, D Sansoni, A Santi, L Sato, H Savard, P Schlabach, P Schmidt, EE Schmidt, MP Schmitt, M Scodellaro, L Scott, A Scribano, A Segler, S Seidel, S Seiya, Y Semenov, A Semeria, F Shah, T Shapiro, MD Shepard, PF Shibayama, T Shimojima, M Shochet, M Siegrist, J Signorelli, G Sill, A Sinervo, P Singh, P Slaughter, AJ Sliwa, K Smith, C Snider, FD Solodsky, A Spalding, J Speer, T Sphicas, P Spinella, F Spiropulu, M Spiegel, L Steele, J Stefanini, A Strologas, J Strumia, F Stuart, D Sumorok, K Suzuki, T Takano, T Takashima, R Takikawa, K Tamburello, P Tanaka, M Tannenbaum, B Taylor, W Tecchio, M Teng, PK Terashi, K Tether, S Theriot, D Thurman-Keup, R Tipton, P Tkaczyk, S Tollefson, K Tollestrup, A Toyoda, H Trischuk, W de Troconiz, JF Tseng, J Turini, N Ukegawa, F Vaiciulis, T Valls, J Vejcik, S Velev, G Vidal, R Vilar, R Volobouev, I Vucinic, D Wagner, RG Wagner, RL Wahl, J Wallace, NB Walsh, AM Wang, C Wang, CH Wang, MJ Watanabe, T Waters, D Watts, T Webb, R Wenzel, H Wester, WC Wicklund, AB Wicklund, E Williams, HH Wilson, P Winer, BL Winn, D Wolbers, S Wolinski, D Wolinski, J Wolinski, S Worm, S Wu, X Wyss, J Yagil, A Yao, W Yeh, GP Yeh, P Yoh, J Yosef, C Yoshida, T Yu, I Yu, S Yu, Z Zanetti, A Zetti, F Zucchelli, S AF Affolder, T Akimoto, H Akopian, A Albrow, MG Amaral, P Amendolia, SR Amidei, D Anikeev, K Antos, J Apollinari, G Arisawa, T Asakawa, T Ashmanskas, W Atac, M Azfar, F Azzi-Bacchetta, P Bacchetta, N Bailey, MW Bailey, S de Barbaro, P Barbaro-Galtieri, A Barnes, VE Barnett, BA Barone, M Bauer, G Bedeschi, F Belforte, S Bellettini, G Bellinger, J Benjamin, D Bensinger, J Beretvas, A Berge, JP Berryhill, J Bevensee, B Bhatti, A Binkley, M Bisello, D Blair, RE Blocker, C Bloom, K Blumenfeld, B Blusk, SR Bocci, A Borras, K Bodek, A Bokhari, W Bolla, G Bonushkin, Y Bortoletto, D Boudreau, J Bindl, A van den Brink, S Bromberg, C Brozovic, M Bruner, N Buckley-Geer, E Budagov, J Budd, HS Burkett, K Busetto, G Byon-Wagner, A Byrum, KL Calafiura, P Campbell, M Carithers, W Carlson, J Carlsmith, D Cassada, J Castro, A Cauz, D Cerri, A Chan, AW Chang, PS Chang, PT Chapman, J Chen, C Chen, YC Cheng, MT Chertok, M Chiarelli, G Chirikov-Zorin, I Chlachidze, G Chlebana, F Christofek, L Chu, RL Ciobanu, CI Clark, AG Connolly, A Convery, M Conway, J Cooper, J Cordelli, M Cranshaw, J Cronin-Hennessy, D Cropp, R Culbertson, R Dagenhart, D 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 Engels, E Erdmann, W Errede, D Errede, S Fan, Q Feild, RG Ferretti, C Field, RD Fiori, I Flaugher, B Foster, GW Franklin, M Freeman, J Friedman, J Fukui, Y Galeotti, S Gallinaro, M Gao, T Garcia-Sciveres, M Garfinkel, AF Gatti, P Gay, C Geer, S Gerdes, DW Giannetti, P Glagolev, V Gold, M Goldstein, J Gordon, A Goshaw, AT Gotra, Y Goulianos, K Green, C Groer, L Grosso-Pilcher, C Guenther, M Guillian, G da Costa, JG Guo, RS Haas, RM Haber, C Hafen, E Hahn, SR Hall, C Handa, T Handler, R Hao, W Happacher, F Hara, K Hardman, AD Harris, RM Hartmann, F Hatakeyama, K Hauser, J Heinrich, J Heiss, A Herndon, M Hinrichsen, B Hoffman, KD Holck, C Hollebeek, R Holloway, L Hughes, R Huston, J Huth, J Ikeda, H Incandela, J Introzzi, G Iwai, J Iwata, Y James, E Jensen, H Jones, M Joshi, U Kamara, H Kamon, T Kaneko, T Karr, K Kasha, H Kato, Y Keaffaber, TA Kelley, K Kelly, M Kennedy, RD Kephart, R Khazins, D Kikuchi, T Kilminster, B Kirby, M Kirk, M Kim, BJ Kim, DH Kim, HS Kim, MJ Kim, SH Kim, YK Kirsch, L Klimenko, S Koehn, P Kongeter, A Kondo, K Konigsberg, J Kordas, K Korn, A Korytov, A Kovacs, E Kroll, J Kruse, M Kuhlmann, SE Kurino, K Kuwabara, T Laasanen, AT Lai, N Lami, S Lammel, S Lamoureux, JI Lancaster, M Latino, G LeCompte, T Lee, AM Lee, K Leone, S Lewis, JD Lindgren, M Liss, TM Liu, JB Liu, YC Lockyer, N Loken, J Loreti, M Lucchesi, D Lukens, P Lusin, S Lyons, L Lys, J Madrak, R Maeshima, K Maksimovic, P Malferrari, L Mangano, M Mariotti, M Martignon, G Martin, A Matthews, JAJ Mayer, J Mazzanti, P McFarland, KS McIntyre, P McKigney, E Melese, P Menguzzato, M Menzione, A Mesropian, C Miao, T Miller, R Miller, JS Minato, H Miscetti, S Mishina, M Mitselmakher, G Moggi, N Moore, C Moore, E Moore, R Morita, Y Mukherjee, A Muller, T Munar, A Murat, P Murgia, S Musy, M Nachtman, J Nahn, S Nakada, H Nakaya, T Nakano, I Nelson, C Neuberger, D Newman-Holmes, C Ngan, CYP Nicolaidi, P Niu, H Nodulman, L Nomerotski, A Oh, SH Ohmoto, T Ohsugi, T Oishi, R Okusawa, T Olsen, J Orejudos, W Pagliarone, C Palmonari, F Paoletti, R Papadimitriou, V Pappas, SP Partos, D Patrick, J Pauletta, G Paulini, M Paus, C Pescara, L Phillips, TJ Piacentino, G Pitts, KT Plunkett, R Pompos, A Pondrom, L Pope, G Popovic, M Prokoshin, F Proudfoot, J Ptohos, F Pukhov, O Punzi, G Ragan, K Rakitine, A Reher, D Reichold, A Riegler, W Ribon, A Rimondi, F Ristori, L Robertson, WJ Robinson, A Rodrigo, T Rolli, S Rosenson, L Roser, R Rossin, R Sakumoto, WK Saltzberg, D Sansoni, A Santi, L Sato, H Savard, P Schlabach, P Schmidt, EE Schmidt, MP Schmitt, M Scodellaro, L Scott, A Scribano, A Segler, S Seidel, S Seiya, Y Semenov, A Semeria, F Shah, T Shapiro, MD Shepard, PF Shibayama, T Shimojima, M Shochet, M Siegrist, J Signorelli, G Sill, A Sinervo, P Singh, P Slaughter, AJ Sliwa, K Smith, C Snider, FD Solodsky, A Spalding, J Speer, T Sphicas, P Spinella, F Spiropulu, M Spiegel, L Steele, J Stefanini, A Strologas, J Strumia, F Stuart, D Sumorok, K Suzuki, T Takano, T Takashima, R Takikawa, K Tamburello, P Tanaka, M Tannenbaum, B Taylor, W Tecchio, M Teng, PK Terashi, K Tether, S Theriot, D Thurman-Keup, R Tipton, P Tkaczyk, S Tollefson, K Tollestrup, A Toyoda, H Trischuk, W de Troconiz, JF Tseng, J Turini, N Ukegawa, F Vaiciulis, T Valls, J Vejcik, S Velev, G Vidal, R Vilar, R Volobouev, I Vucinic, D Wagner, RG Wagner, RL Wahl, J Wallace, NB Walsh, AM Wang, C Wang, CH Wang, MJ Watanabe, T Waters, D Watts, T Webb, R Wenzel, H Wester, WC Wicklund, AB Wicklund, E Williams, HH Wilson, P Winer, BL Winn, D Wolbers, S Wolinski, D Wolinski, J Wolinski, S Worm, S Wu, X Wyss, J Yagil, A Yao, W Yeh, GP Yeh, P Yoh, J Yosef, C Yoshida, T Yu, I Yu, S Yu, Z Zanetti, A Zetti, F Zucchelli, S TI Dijet production by double Pomeron exchange at the Fermilab Tevatron SO PHYSICAL REVIEW LETTERS LA English DT Article ID LARGE RAPIDITY GAPS; SURVIVAL PROBABILITY; DIFFRACTION AB We report the first observation of dijet events with a double Pomeron exchange topology produced in (p) over barp, collisions at roots = 1800 GeV. The events are characterized by a leading antiproton, two jets in the central pseudorapidity region, and a large rapidity gap on the outgoing proton side. We present results on jet kinematics and production rates, compare them with corresponding results from single diffractive and inclusive dijet production, and test factorization. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Acad Sinica, Inst Phys, Taipei 11529, Taiwan. 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 Cantabria, Inst Fis Cantabria, CSIC, E-39005 Santander, Spain. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Joint Nucl Res Inst, RU-141980 Dubna, Russia. Duke Univ, Durham, NC 27708 USA. Fermilab 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. Johns Hopkins Univ, Baltimore, MD 21218 USA. Univ Karlsruhe, Inst Expt Kernphys, D-76128 Karlsruhe, Germany. Kyungpook Natl Univ, Korean Hadron Collider Lab, Taegu 702701, South Korea. Seoul Natl Univ, Seoul 151742, South Korea. Sungkyunkwan Univ, Suwon 440746, South Korea. KEK, High Energy Accelerator Res Org, Tsukuba, Ibaraki 305, Japan. MIT, Cambridge, MA 02139 USA. McGill Univ, Inst Particle Phys, Montreal, PQ H3A 2T8, Canada. Univ Toronto, Toronto, ON M5S 1A7, Canada. 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 Oxford, Oxford OX1 3RH, England. 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. Rockefeller Univ, New York, NY 10021 USA. Univ Rochester, Rochester, NY 10021 USA. Rutgers State Univ, Piscataway, NJ 08855 USA. Texas A&M Univ, College Stn, TX 77843 USA. Texas Tech Univ, Lubbock, TX 79409 USA. Univ Trieste, Ist Nazl Fis Nucl, Udine, Italy. Univ Tsukuba, Tsukuba, Ibaraki 305, Japan. Tufts Univ, Medford, MA 02155 USA. Waseda Univ, Tokyo 169, Japan. Univ Wisconsin, Madison, WI 53706 USA. Yale Univ, New Haven, CT 06520 USA. RP Affolder, T (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RI Lancaster, Mark/C-1693-2008; Vucinic, Dejan/C-2406-2008; Nomerotski, Andrei/A-5169-2010; Azzi, Patrizia/H-5404-2012; Punzi, Giovanni/J-4947-2012; Chiarelli, Giorgio/E-8953-2012; Scodellaro, Luca/K-9091-2014; Paulini, Manfred/N-7794-2014; Prokoshin, Fedor/E-2795-2012; Introzzi, Gianluca/K-2497-2015; OI Azzi, Patrizia/0000-0002-3129-828X; Punzi, Giovanni/0000-0002-8346-9052; Chiarelli, Giorgio/0000-0001-9851-4816; Scodellaro, Luca/0000-0002-4974-8330; Paulini, Manfred/0000-0002-6714-5787; Prokoshin, Fedor/0000-0001-6389-5399; Introzzi, Gianluca/0000-0002-1314-2580; Latino, Giuseppe/0000-0002-4098-3502; Wyss, Jeffery/0000-0002-8277-4012; Lancaster, Mark/0000-0002-8872-7292; Gallinaro, Michele/0000-0003-1261-2277; Turini, Nicola/0000-0002-9395-5230; CHANG, PAO-TI/0000-0003-4064-388X; Signorelli, Giovanni/0000-0001-8262-8245; Goldstein, Joel/0000-0003-1591-6014 NR 18 TC 76 Z9 76 U1 0 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 NOV 13 PY 2000 VL 85 IS 20 BP 4215 EP 4220 DI 10.1103/PhysRevLett.85.4215 PG 6 WC Physics, Multidisciplinary SC Physics GA 372RK UT WOS:000165247700006 ER PT J AU Wilson, KR Tobin, JG Ankudinov, AL Rehr, JJ Saykally, RJ AF Wilson, KR Tobin, JG Ankudinov, AL Rehr, JJ Saykally, RJ TI Extended x-ray absorption fine structure from hydrogen atoms in water SO PHYSICAL REVIEW LETTERS LA English DT Article ID NEAR-EDGE STRUCTURE; K-SHELL EXCITATION; MULTIPLE-SCATTERING; H2O AB We report the first quantitative measurement of extended x-ray absorption fine structure (EXAFS) from hydrogen atoms. A single oscillation is observed from gaseous water consistent with the location of the covalently bonded hydrogen in H2O. The experimental phase and amplitude of the oscillation are in excellent agreement with curved wave multiple scattering calculations for isolated water molecules. With this determination of the O-H scattering phase shift we have quantified the covalent hydrogen bond distance (0.95 +/- 0.03 Angstrom) in liquid water, thus demonstrating that hydrogen EXAFS can become a valuable complement to existing structural methods in chemistry and biology. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Washington, Dept Phys, Seattle, WA 98195 USA. RP Saykally, RJ (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 16 TC 37 Z9 37 U1 1 U2 8 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD NOV 13 PY 2000 VL 85 IS 20 BP 4289 EP 4292 DI 10.1103/PhysRevLett.85.4289 PG 4 WC Physics, Multidisciplinary SC Physics GA 372RK UT WOS:000165247700024 ER PT J AU Yamakov, V Milchev, A Limbach, HJ Dunweg, B Everaers, R AF Yamakov, V Milchev, A Limbach, HJ Dunweg, B Everaers, R TI Conformations of random polyampholytes SO PHYSICAL REVIEW LETTERS LA English DT Article ID MOLECULAR-DYNAMICS; CHARGED POLYMERS; CHAIN; COLLAPSE; WALK AB We study the size R-g of random polyampholytes (i.e., polymers with randomly charged monomers) as a function of their length N. All results of our extensive Monte Carlo simulations can be rationalized in terms of the scaling theory we develop for the Kantor-Kardar necklace model, although this theory neglects the quenched disorder in the charge sequence along the chain. We find (R-g) proportional to N1/2. Th, elongated globule model, the initial predictions of both Higgs and Joanny (proportional to N1/3) and Kantor and Kardar (proportional to N), and previous numerical estimates are ruled out. C1 Max Planck Inst Polymerforsch, D-55021 Mainz, Germany. Bulgarian Acad Sci, Inst Chem Phys, BU-1113 Sofia, Bulgaria. RP Yamakov, V (reprint author), Argonne Natl Lab, Div Mat Sci, Bldg 212,9700 S Cass Ave, Argonne, IL 60439 USA. RI Everaers, Ralf/K-2228-2013; MPIP, Theory/I-9884-2014; Duenweg, Burkhard/J-1126-2014; Milchev, Andrey/S-4118-2016 OI Everaers, Ralf/0000-0002-6843-2753; Duenweg, Burkhard/0000-0001-7769-5865; Milchev, Andrey/0000-0003-1991-0648 NR 28 TC 37 Z9 38 U1 1 U2 8 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD NOV 13 PY 2000 VL 85 IS 20 BP 4305 EP 4308 DI 10.1103/PhysRevLett.85.4305 PG 4 WC Physics, Multidisciplinary SC Physics GA 372RK UT WOS:000165247700028 ER PT J AU Nakao, H Ohwada, K Takesue, N Fujii, Y Isobe, M Ueda, Y Von Zimmermann, M Hill, JP Gibbs, D Woicik, JC Koyama, I Murakami, Y AF Nakao, H Ohwada, K Takesue, N Fujii, Y Isobe, M Ueda, Y Von Zimmermann, M Hill, JP Gibbs, D Woicik, JC Koyama, I Murakami, Y TI X-ray anomalous scattering study of a charge-ordered state in NaV2O5 SO PHYSICAL REVIEW LETTERS LA English DT Article ID SPIN-PEIERLS COMPOUND; ALPHA'-NAV2O5; TEMPERATURE; TRANSITION; SYSTEMS; EDGE AB Charge ordering of V4+ and V5+ in NaV2O5 has been studied by an x-ray diffraction technique using anomalous scattering near a vanadium K-absorption edge to critically enhance a contrast between the two ions. A dramatic energy dependence of the superlattice intensities is observed below T-C = 35 K. The charge ordering pattern is the fully charged zigzag-type ladder with the unit cell 2a X 2b X 4c, but not the chain-type originally proposed for the spin-Peierls state. Charge disproportionation suggested in our model as the average valence V4.5+/-deltac/2 is observed below T-C, showing continuous variation of delta (c) as a function of temperature. C1 Univ Tokyo, Inst Solid State Phys, Neutron Scattering Lab, Tokai, Ibaraki 3191106, Japan. Univ Tokyo, Inst Solid State Phys, Mat Design & Characterizat Lab, Minato Ku, Tokyo 1068666, Japan. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. High Energy Accelerator Res Org KEK, Inst Mat Struct Sci, Photon Factory, Tsukuba, Ibaraki 3050801, Japan. RP Nakao, H (reprint author), High Energy Accelerator Res Org KEK, Inst Mat Struct Sci, Photon Factory, Tsukuba, Ibaraki 3050801, Japan. RI Isobe, Masahiko/B-5616-2015 NR 26 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 NOV 13 PY 2000 VL 85 IS 20 BP 4349 EP 4352 DI 10.1103/PhysRevLett.85.4349 PG 4 WC Physics, Multidisciplinary SC Physics GA 372RK UT WOS:000165247700039 ER PT J AU Zaliznyak, IA Hill, JP Tranquada, JM Erwin, R Moritomo, Y AF Zaliznyak, IA Hill, JP Tranquada, JM Erwin, R Moritomo, Y TI Independent freezing of charge and spin dynamics in La1.5Sr0.5CoO4 SO PHYSICAL REVIEW LETTERS LA English DT Article ID MAGNETIC ORDER; SUPERCONDUCTIVITY; PHASE; LA0.5CA0.5MNO3; LA0.5SR1.5MNO4; MANGANITES AB We present elastic and quasielastic neutron scattering measurements characterizing peculiar short-range charge-orbital and spin order in the layered perovskite material La1.5Sr0.5CoO4. We find that below T-c approximate to 750 K holes introduced by Sr doping lose mobility and enter a statically ordered charge glass phase with loosely correlated checkerboard arrangement of empty and occupied d(3z)2-r(2) orbitals (Co3+ and Co2+). The dynamics of the resultant mixed spin system is governed by the anisotropic nature of the crystal-field Hamiltonian and the peculiar exchange pattern produced by the orbital order. It undergoes a spin freezing transition at a much lower temperature, T-s less than or similar to 30 K. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Nagoya Univ, CIRSE, Nagoya, Aichi 46401, Japan. Nagoya Univ, Dept Appl Phys, Nagoya, Aichi 46401, Japan. RP Zaliznyak, IA (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RI Tranquada, John/A-9832-2009; Hill, John/F-6549-2011; Zaliznyak, Igor/E-8532-2014; OI Tranquada, John/0000-0003-4984-8857; Zaliznyak, Igor/0000-0002-9886-3255; moritomo, yutaka/0000-0001-6584-7489 NR 22 TC 66 Z9 66 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 NOV 13 PY 2000 VL 85 IS 20 BP 4353 EP 4356 DI 10.1103/PhysRevLett.85.4353 PG 4 WC Physics, Multidisciplinary SC Physics GA 372RK UT WOS:000165247700040 ER PT J AU Bradley, K Jhi, SH Collins, PG Hone, J Cohen, ML Louie, SG Zettl, A AF Bradley, K Jhi, SH Collins, PG Hone, J Cohen, ML Louie, SG Zettl, A TI Is the intrinsic thermoelectric power of carbon nanotubes positive? SO PHYSICAL REVIEW LETTERS LA English DT Article ID SINGLE-WALL AB The thermoelectric power (TEP) of single-walled carbon nanotubes (SWNTs) is extremely sensitive to gas exposure history. Samples exposed to air or oxygen have an always positive TEP, suggestive of holelike carriers. However, at fixed temperature the TEP crosses zero and becomes progressively more negative as the SWNTs are stripped of oxygen. The time constant for oxygen adsorption/desorption is strongly temperature dependent and ranges from seconds to many days, leading to apparently "variable" TEP for a given sample at a given temperature. The saturated TEP can be accounted for within a model of strong oxygen doping of the semiconducting nanotubes. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Zettl, A (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Hone, James/E-1879-2011; Zettl, Alex/O-4925-2016 OI Hone, James/0000-0002-8084-3301; Zettl, Alex/0000-0001-6330-136X NR 19 TC 171 Z9 172 U1 2 U2 24 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 NOV 13 PY 2000 VL 85 IS 20 BP 4361 EP 4364 DI 10.1103/PhysRevLett.85.4361 PG 4 WC Physics, Multidisciplinary SC Physics GA 372RK UT WOS:000165247700042 ER PT J AU Raman, S Yonezawa, C Matsue, H Iimura, H Shinohara, N AF Raman, S Yonezawa, C Matsue, H Iimura, H Shinohara, N TI Efficiency calibration of a Ge detector in the 0.1-11.0 MeV region SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID THERMAL-NEUTRON CAPTURE; GAMMA-RAY SPECTRA; RELATIVE INTENSITIES; AUTOMATIC-ANALYSIS; DAUGHTER PRODUCTS; ENERGY-RANGE; STANDARD; RA-226; DECAY; EQUILIBRIUM AB An efficiency curve was constructed for a large-volume Ge detector located at the thermal-neutron beam line of the JRR-3M reactor at the Japan Atomic Energy Research Institute (JAERI). The calibrations for gamma -ray energies below 2754 keV were accomplished with a large number of radioactive sources and above 2754 keV with the C-12(n,gamma) and N-14(n,gamma) reactions. This detector and its efficiency curve were subsequently used to determine accurately the photon emission probabilities of gamma rays from the decays of Co-56 (T-1/2 = 77 d) and Ga-66 (9.5 h) and from the Cl-35(n,gamma) reaction. These radiation sources can serve as secondary standards for efficieney calibrations. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Japan Atom Energy Res Inst, Tokai, Ibaraki 3191195, Japan. RP Raman, S (reprint author), Oak Ridge Natl Lab, Div Phys, Bldg 6010 MS 6354, Oak Ridge, TN 37831 USA. NR 43 TC 39 Z9 40 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 NOV 11 PY 2000 VL 454 IS 2-3 BP 389 EP 402 DI 10.1016/S0168-9002(00)00493-9 PG 14 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 377LC UT WOS:000165514200011 ER PT J AU Shapira, D Lewis, TA Hulett, LD AF Shapira, D Lewis, TA Hulett, LD TI A fast and accurate position-sensitive timing detector based on secondary electron emission SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE timing; position-sensitive; particle detectors; heavy-ion beams; radioactive beams; tracking; secondary electrons; microchannel plate detectors ID CHARGED-PARTICLES; PLATE DETECTOR; HEAVY-IONS; FACILITY; BEAMS AB A position-sensitive timing detector suitable for detection of low-energy heavy ions is described. The device is based on the detection of secondary electrons emitted following ion impact on a surface. Using a combination of magnetic and electric fields these devices can deliver sub-nanosecond time definition and sub-millimeter position information for ion impact even at incidence rates above 10(6) p/s. When choosing a thin foil for the surface intercepting the heavy ion trajectory, multiple detectors can be used and reliable tracking of heavy ions with moderate energies (greater than or equal to 1 MeV/A) becomes feasible. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Instrumentat & Control Div, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Shapira, D (reprint author), Oak Ridge Natl Lab, Div Phys, POB 2008, Oak Ridge, TN 37831 USA. NR 34 TC 61 Z9 61 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 NOV 11 PY 2000 VL 454 IS 2-3 BP 409 EP 420 DI 10.1016/S0168-9002(00)00499-X PG 12 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 377LC UT WOS:000165514200013 ER PT J AU Saxena, AM AF Saxena, AM TI Characteristics of thin-film multilayer monochromator systems from ray-tracing calculations SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE neutron diffractometer; multilayer monochromator; Monte Carlo; ray tracing ID NI-TI MULTILAYERS; NEUTRON; SUPERMIRRORS; DIFFUSION AB A ray-tracing program was developed based on the Monte Carlo method to analyze the performance of a monochromating system based on thin-film multilayer monochromators. The monochromating assembly consisted of a collimator before the multilayer for limiting the dimensions of the beam incident on either one or two multilayer monochromators that reflect the neutron beam, and a final collimator after the multilayer to decrease the cross-section of the beam to match the sample, and also to reduce Delta lambda/lambda of the emerging neutrons by limiting their divergence. The results show that, in general, the bandwidth of the beam reaching the spectrometer will be narrower than the value predicted by the differential form of Bragg's law, and its dependence on the widths of the slits will also be significantly less. The large bandwidth of the reflected beam, that is normally obtained from these monochromators, does not necessarily imply a greater neutron flux. Imperfections, either natural or intentionally built-in during the deposition process, directly influence the intensity of the reflected beam. A perfect multilayer will not reflect a significant portion of the incident beam even though its bandwidth Delta lambda/lambda may be large, and a multilayer with appropriate variations in d-spacings may be used to increase the intensity available for the experiments. In many situations, the use of a multilayer with smaller d-spacings will be advantageous if the reflectivity can still be maintained at a high value. For a two-multilayer system, the reflected intensity will be significantly less even if the second multilayer is exactly identical to the first and, for unidentical multilayers, there will be a further degradation of neutron flux. In both cases, the bandwidth Delta lambda/lambda will remain essentially the same as for reflection from a single multilayer. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Saxena, AM (reprint author), Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. NR 21 TC 2 Z9 3 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 NOV 11 PY 2000 VL 454 IS 2-3 BP 426 EP 439 DI 10.1016/S0168-9002(00)00491-5 PG 14 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 377LC UT WOS:000165514200015 ER PT J AU Saxena, AM AF Saxena, AM TI Neutron focusing devices based on segmented thin-film multilayers SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE neutron focusing; multilayer; Monte Carlo; ray tracing ID X-RAY; MONOCHROMATORS; SUPERMIRRORS; DIFFRACTION AB A neutron converging device has been designed using sections of thin-film multilayer monochromators with the help of ray-tracing calculations (Saxena, Nucl. Instr. and Meth. A 454 (2000) 428, this issue). The device consists of an odd number of sections of multilayers. The central section will have a periodicity and angular orientation with respect to the mean ray that reflects the desired wavelength. The orientation of other sections was adjusted so that the reflected beam from these sections was coincident with that from the middle section. Since a rotation of sections also changes the wavelength of the reflected beam, the d-spacings of the peripheral sections were adjusted to reflect the same wavelength as the middle section. The convergence factor (gain in intensity) will depend on the areas of the primary beam and that of the sample, and also on the number of sections used in the focusing device. For a typical geometry, intensity may be increased by a factor of two or more. Used alone, such a device will both focus and monochromate the neutron beam to give a rather large Delta lambda/lambda, that is typical of thin-film multilayer monochromators. However, a device of this type may also be used to focus a neutron beam that has already been monochromated by reflection from a crystal monochromator. In this case, the neutron beam will be focused without a significant change of spectrum. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Saxena, AM (reprint author), Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. EM asaxena@bnl.gov NR 14 TC 1 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD NOV 11 PY 2000 VL 454 IS 2-3 BP 440 EP 451 DI 10.1016/S0168-9002(00)00490-3 PG 12 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 377LC UT WOS:000165514200016 ER PT J AU Franco, LM Link, B Epstein, RI AF Franco, LM Link, B Epstein, RI TI Quaking neutron stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE dense matter; magnetic fields; pulsars : individual (Crab pulsar); stars : magnetic fields; stars : neutron ID CRUSTAL PLATE-TECTONICS; SOFT GAMMA-REPEATERS; PULSAR GLITCHES; MAGNETIC-FIELD; RAY BURSTS; EVOLUTION; CRAB AB Gravitational, magnetic, and superfluid forces can stress the crust of an evolving neutron star. Fracture of the crust under these stresses could affect the star's spin evolution and generate high-energy emission. We study the growth of strain in the crust of a spinning down, magnetized neutron star and examine the initiation of crust cracking (a starquake). In preliminary work in 1998 we studied a homogeneous model of a neutron star. Here we extend this work by considering a more realistic model of a solid, homogeneous crust a afloat on a liquid core. In the limits of astrophysical interest, our new results qualitatively agree with those from the simpler model: the stellar crust fractures under shear stress at the rotational equator, matter moves to higher latitudes, and the star's oblateness is reduced. Magnetic stresses favor faults directed toward the magnetic poles. Thus our previous conclusions concerning the star's spin response still hold; namely, asymmetric redistribution of matter excites damped precession, which could ultimately lead to an increase in the spin-down torque. Starquakes associated with glitches could explain the permanent offsets in period derivative observed to follow glitches in at least three pulsars. C1 Univ Chicago, Chicago, IL 60637 USA. Montana State Univ, Dept Phys, Bozeman, MT 59717 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Franco, LM (reprint author), Univ Chicago, 5640 S Ellis Ave, Chicago, IL 60637 USA. EM lucia@oddjob.uchicago.edu; blink@dante.physics.montana.edu; epstein@lanl.gov NR 28 TC 47 Z9 47 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 10 PY 2000 VL 543 IS 2 BP 987 EP 994 DI 10.1086/317121 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 378TD UT WOS:000165599300041 ER PT J AU Blanton, M Lin, H AF Blanton, M Lin, H TI The distribution of [O II] emission-line widths of Las Campanas Redshift Survey galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : fundamental parameters; galaxies : luminosity function, mass function; galaxies : statistics ID LUMINOSITY FUNCTION; EVOLUTION; FIELD; DENSITY AB We present a simple functional form for the joint distribution of R-band luminosity and [O II] lambda 3727 emission-line equivalent widths of galaxies and show that this form is a good fit to the galaxies in the Las Campanas Redshift Survey. We find a relationship between [O II] equivalent width W and R-band luminosity L-R of the approximate form (W) approximate to (10 Angstrom)(L-R/L-R,(*))(-1/2), where L-R,L-*. is the characteristic luminosity in the Schechter function. Because this joint distribution yields information about the relationship between stellar mass in a galaxy and its recent star formation rate, it can be useful for testing theories of galaxy formation. Furthermore, understanding this joint distribution locally will make it easier to interpret the evolution of [O II] emission-line widths to higher redshifts. C1 NASA, Fermi Natl Accelerator Lab, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. RP Blanton, M (reprint author), NASA, Fermi Natl Accelerator Lab, Fermilab Astrophys Ctr, POB 500, Batavia, IL 60510 USA. NR 22 TC 6 Z9 6 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 NOV 10 PY 2000 VL 543 IS 2 BP L125 EP L128 DI 10.1086/317283 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 378TE UT WOS:000165599400008 ER PT J AU Sako, M Kahn, SM Paerels, F Liedahl, DA AF Sako, M Kahn, SM Paerels, F Liedahl, DA TI The Chandra high-energy transmission grating observation of an X-ray ionization cone in Markarian 3 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (Markarian 3); galaxies : nuclei; galaxies : Seyfert; techniques : spectroscopic; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; NARROW-LINE REGION; SEYFERT-GALAXIES; ABSORPTION LINES; EMISSION; SPECTROPOLARIMETRY; SPECTROMETER; CONTINUUM; NGC-1068; SPECTRA AB We present a preliminary analysis of the first high-resolution X-ray spectrum of a Seyfert 2 galaxy, Markarian 3, obtained with the High-Energy Transmission Grating Spectrometer on board the Chandra X-Ray Observatory. The high-energy spectrum (lambda less than or similar to 4 Angstrom) is dominated by reflection of the active galactic nucleus continuum radiation in a cold, optically thick medium and contains bright Ka! fluorescent lines from iron and silicon as well as weak, blended lines from sulfur and magnesium. The soft X-ray emission (4 Angstrom less than or similar to lambda 23 Angstrom) is spatially extended along the [O III] ionization cone and shows discrete signatures of emission following recombination and photoexcitation produced in a warm photoionized region. The measured iron L line fluxes indicate that emission from collisionally ionized plasma is almost completely negligible and does not contribute significantly to the total energy budget of the X-ray emission. We find that significant fractions of the H- and He-like resonance lines, as well as the observed iron L lines, are produced through reemission from the warm absorbing medium observed in Seyfert 1 galaxies. Its X-ray spectral properties are qualitatively consistent with those of a typical Seyfert 1 galaxy viewed at a different orientation and provide further convincing evidence for the existence of an obscured Seyfert 1 nucleus in Mrk 3. C1 Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. Columbia Univ, Dept Phys, New York, NY 10027 USA. Lawrence Livermore Natl Lab, Dept Phys, Livermore, CA 94550 USA. RP Sako, M (reprint author), Columbia Univ, Columbia Astrophys Lab, 538 W 120th St, New York, NY 10027 USA. EM masao@astro.columbia.edu; skahn@astro.columbia.edu; frits@astro.columbia.edu; duane@leo.llnl.gov NR 29 TC 128 Z9 128 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 10 PY 2000 VL 543 IS 2 BP L115 EP L118 DI 10.1086/317282 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 378TE UT WOS:000165599400006 ER PT J AU Sousa, MC Trame, CB Tsuruta, H Wilbanks, SM Reddy, VS McKay, DB AF Sousa, MC Trame, CB Tsuruta, H Wilbanks, SM Reddy, VS McKay, DB TI Crystal and solution structures of an HsIUV protease-chaperone complex SO CELL LA English DT Article ID ATP-DEPENDENT PROTEASE; ESCHERICHIA-COLI HOMOLOG; CELL-DIVISION INHIBITOR; PROTEOLYTIC ACTIVITY; TAGGING SYSTEM; 20S PROTEASOME; HSLVU PROTEASE; BETA-SUBUNITS; PROTEINS; SCATTERING AB HslUV is a "prokaryotic proteasome" composed of the HslV protease and the HslU ATPase, a chaperone of the Clp/Hsp100 family. The 3.4 a crystal structure of an HslUV complex is presented here. Two hexameric ATP binding rings of HslU bind intimately to opposite sides of the HslV protease; the HslU "intermediate domains" extend outward from the complex. The solution structure of HslUV, derived from small angle X-ray scattering data under conditions where the complex is assembled and active, agrees with this crystallographic structure. When the complex forms, the carboxy-terminal helices of HslU distend and bind between subunits of HslV, and the apical helices of HsIV shift substantially, transmitting a conformational change to the active site region of the protease. C1 Stanford Univ, Sch Med, Dept Biol Struct, Stanford, CA 94305 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. Scripps Res Inst, Dept Mol Biol, La Jolla, CA 92037 USA. RP McKay, DB (reprint author), Stanford Univ, Sch Med, Dept Biol Struct, Stanford, CA 94305 USA. FU NCRR NIH HHS [RR12255]; NIGMS NIH HHS [GM-39928] NR 45 TC 226 Z9 230 U1 0 U2 7 PU CELL PRESS PI CAMBRIDGE PA 1050 MASSACHUSETTES AVE, CIRCULATION DEPT, CAMBRIDGE, MA 02138 USA SN 0092-8674 J9 CELL JI Cell PD NOV 10 PY 2000 VL 103 IS 4 BP 633 EP 643 DI 10.1016/S0092-8674(00)00166-5 PG 11 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 374MB UT WOS:000165348000008 PM 11106733 ER PT J AU Fulton, JL Hoffmann, MM Darab, JG AF Fulton, JL Hoffmann, MM Darab, JG TI An X-ray absorption fine structure study of copper(I) chloride coordination structure in water up to 325 degrees C SO CHEMICAL PHYSICS LETTERS LA English DT Article ID SUPERCRITICAL WATER; MOLECULAR-DYNAMICS; HYDROTHERMAL SOLUTIONS; AQUEOUS-SOLUTIONS; EXAFS; COMPLEXES; XAFS; 300-DEGREES-C; SPECTROSCOPY; SCATTERING AB X-ray absorption fine structure (XAFS) spectroscopy was used to measure the Cl- and H2O coordination structure about Cu1+ in water at temperatures up to 325 degreesC including the coordination numbers, symmetry, distances and the amount of bond disorder. The linear dichloro Cu1+ species, [CuCl2](-), is especially stable and it is predominant from 100 degreesC to 325 degreesC in the presence of excess Cl-. Even for solutions with 2.0 m NaCl, only the dichloro Cu1+ species is observed with no evidence of higher Cl- coordination. There is no evidence of hydration waters in the first-solvation shell of this dichloro-species. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Pacific NW Natl Lab, Environm & Hlth Sci Div, Richland, WA 99352 USA. RP Fulton, JL (reprint author), Pacific NW Natl Lab, Environm & Hlth Sci Div, Battelle Blvd,POB 999, Richland, WA 99352 USA. NR 29 TC 57 Z9 61 U1 0 U2 6 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 NOV 10 PY 2000 VL 330 IS 3-4 BP 300 EP 308 DI 10.1016/S0009-2614(00)01110-6 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 375TT UT WOS:000165417900014 ER PT J AU Kraabel, B McBranch, DW AF Kraabel, B McBranch, DW TI Subpicosecond study of excitons in a phenylenevinylene conjugated polymer: exciton-exciton interactions and infrared photoinduced absorption features SO CHEMICAL PHYSICS LETTERS LA English DT Article ID POLYDIACETYLENE CHAINS; TRANSIENT-ABSORPTION; EMISSION; SPECTROSCOPY; GENERATION; RELAXATION; DIODES; FILMS AB We present a study of the fundamental photoexcitations in a phenylenevinylene conjugated polymer from the visible to the mid-infrared (IR) using polarized subpicosecond transient absorption (TA) spectroscopy. From 0.5 to roughly 1.3 eV we find that features due to singlet intrachain excitons dominate the photoinduced absorption. Two peaks are apparent in the spectrum: one near 0.5 eV and the other at similar to1.1 eV. In the regime of high excitation densities (> 10(19) cm(-3)), we find evidence of exciton-exciton interactions leading to exciton hopping between different chains or segments of the polymer. (C) 2000 Published by Elsevier Science B.V. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. ViewGate Networks, Sevenoaks TN13 1XJ, England. RP Kraabel, B (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, CST-6,MS-J567, Los Alamos, NM 87545 USA. NR 24 TC 11 Z9 12 U1 0 U2 3 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 NOV 10 PY 2000 VL 330 IS 3-4 BP 403 EP 409 DI 10.1016/S0009-2614(00)00994-5 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 375TT UT WOS:000165417900028 ER PT J AU Rodriguez, JA Jirsak, J Kim, JY Larese, JZ Maiti, A AF Rodriguez, JA Jirsak, J Kim, JY Larese, JZ Maiti, A TI Interaction of NO and NO2 with MgO(100): photoemission and density-functional studies SO CHEMICAL PHYSICS LETTERS LA English DT Article ID SURFACE; CHEMISORPTION; FILMS; SPECTROSCOPY; MO(100); WATER AB High resolution photoemission and first-principles density-functional calculations (DF-GGA) were used to study the chemistry of NO and NO2 on MgO(1 0 0). NO is weakly adsorbed. DF results predict an NO adsorption energy of 6 kcal/mol, close to the experimental value of similar to4 kcal/mol. On MgO1-x, O vacancies enhance the bonding energy of NO and lead to N2O and N production. NO2 is very reactive on MgO(1 0 0) forming NO3 species. The large differences in the reactivity of NO and NO2 reflect the fact that nitrogen dioxide is a good electron acceptor and its orbitals mix better with the occupied bands of MgO. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Mol Simulat Inc, San Diego, CA 92121 USA. RP Rodriguez, JA (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. NR 34 TC 43 Z9 43 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD NOV 10 PY 2000 VL 330 IS 3-4 BP 475 EP 483 DI 10.1016/S0009-2614(00)01098-8 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 375TT UT WOS:000165417900038 ER PT J AU Kim, WJ Lee, S Park, MS Jang, YK Kim, JB Park, SD AF Kim, WJ Lee, S Park, MS Jang, YK Kim, JB Park, SD TI Rad22 protein, a Rad52 homologue in Schizosaccharomyces pombe, binds to DNA double-strand breaks SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID FISSION YEAST; SACCHAROMYCES-CEREVISIAE; RECOMBINATION; REPAIR; REPLICATION; PATHWAYS; GENES AB DNA double-strand breaks can be introduced by exogenous agents or during normal cellular processes. Genes belonging to the RAD52 epistasis group are known to repair these breaks in budding yeast. Among these genes, RAD52 plays a central role in homologous recombination and DNA double-strand break repair. Despite its importance, its mechanism of action is not yet clear. It is known, however, that the human homologue of Rad52 is capable of binding to DNA ends in vitro. Herein, we show that Rad22 protein, a Rad52 homologue in the fission yeast Schizosaccharomyces pombe, can similarly bind to DNA ends at double-strand breaks. This end-binding ability was demonstrated in vitro by electron microscopy and by protection from exonuclease attack. We also showed that Rad22 specifically binds near double-strand break associated with mating type switching in vivo by chromatin immunoprecipitation analysis. This is the first evidence that a recombinational protein directly binds to DNA double-strand breaks in vivo. C1 Seoul Natl Univ, Sch Biol Sci, Seoul 151742, South Korea. CHA Gen Hosp, Pochon CHA Med Sch, Genet Lab, Tokyo 135081, Japan. Univ Calif Los Alamos Natl Lab, Div Biosci, Los Alamos, NM 87545 USA. RP Park, SD (reprint author), Seoul Natl Univ, Sch Biol Sci, Seoul 151742, South Korea. OI KIM, Jae Bum/0000-0003-2337-6935 NR 28 TC 22 Z9 25 U1 0 U2 0 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 NOV 10 PY 2000 VL 275 IS 45 BP 35607 EP 35611 DI 10.1074/jbc.M007060200 PG 5 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 375VW UT WOS:000165422800102 PM 10956666 ER PT J AU Brisbin, IL Austad, S Jacobson, SK AF Brisbin, IL Austad, S Jacobson, SK TI Canine Detectives: The nose knows - or does it? SO SCIENCE LA English DT Letter ID SCENT; DOGS C1 Savannah River Ecol Lab, Aiken, SC 29802 USA. Univ Idaho, Dept Biol Sci, Moscow, ID 83844 USA. State Colorado Off State Publ Defernder, Boulder, CO 80301 USA. RP Brisbin, IL (reprint author), Savannah River Ecol Lab, Aiken, SC 29802 USA. NR 6 TC 8 Z9 8 U1 1 U2 6 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 NOV 10 PY 2000 VL 290 IS 5494 BP 1093 EP 1093 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 372HL UT WOS:000165228200018 PM 11185001 ER PT J AU Smith, SJ Wigley, TML Edmonds, J AF Smith, SJ Wigley, TML Edmonds, J TI Climate - A new route toward limiting climate change? SO SCIENCE LA English DT Editorial Material C1 Pacific NW Natl Lab, Washington, DC 20024 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. RP Smith, SJ (reprint author), Pacific NW Natl Lab, 901 D St NW, Washington, DC 20024 USA. RI Wigley, Tom/B-4705-2008 NR 6 TC 8 Z9 9 U1 0 U2 2 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD NOV 10 PY 2000 VL 290 IS 5494 BP 1109 EP 1110 DI 10.1126/science.290.5494.1109 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 372HL UT WOS:000165228200034 PM 17743257 ER PT J AU Davis, KJ Dove, PM De Yoreo, JJ AF Davis, KJ Dove, PM De Yoreo, JJ TI The role of Mg2+ as an impurity in calcite growth SO SCIENCE LA English DT Article ID CRYSTAL-GROWTH; MAGNESIUM; CARBONATE; KINETICS; CRYSTALLIZATION; THERMODYNAMICS; 25-DEGREES-C; ARAGONITE; WATER AB Magnesium is a key determinant in CaCO3 mineralization; however, macroscopic observations have failed to provide a clear physical understanding of how magnesium modifies carbonate growth. Atomic force microscopy was used to resolve the mechanism of calcite inhibition by magnesium through molecular-scale determination of the thermodynamic and kinetic controls of magnesium on calcite formation. Comparison of directly measured step velocities to standard impurity models demonstrated that enhanced mineral solubility through magnesium incorporation inhibited calcite growth. Terrace width measurements on calcite growth spirals were consistent with a decrease in effective supersaturation due to magnesium incorporation. Ca1-xMgxCO3 solubilities determined from microscopic observations of step dynamics can thus be Linked to macroscopic measurements. C1 Virginia Polytech Inst & State Univ, Dept Geol Sci, Blacksburg, VA 24061 USA. Univ Calif Lawrence Livermore Natl Lab, Dept Chem & Mat Sci, Livermore, CA 94550 USA. RP Dove, PM (reprint author), Virginia Polytech Inst & State Univ, Dept Geol Sci, Blacksburg, VA 24061 USA. RI Dove, Patricia/A-7911-2010 NR 27 TC 372 Z9 385 U1 12 U2 180 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 NOV 10 PY 2000 VL 290 IS 5494 BP 1134 EP 1137 DI 10.1126/science.290.5494.1134 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 372HL UT WOS:000165228200039 PM 11073446 ER PT J AU Williams, S Harding, LB Stanton, JF Weisshaar, JC AF Williams, S Harding, LB Stanton, JF Weisshaar, JC TI Barrier to methyl internal rotation of cis- and trans-2-methylvinoxy radicals in the (X)over-tilde((2)A '') and (B)over-tilde((2)A '') states: Experiment and theory SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID LASER-INDUCED FLUORESCENCE; INTRAMOLECULAR VIBRATIONAL REDISTRIBUTION; CONFIGURATION-INTERACTION CALCULATIONS; CORRELATED MOLECULAR CALCULATIONS; COUPLED-CLUSTER METHOD; GAUSSIAN-BASIS SETS; P-FLUOROTOLUENE; OXYGEN-ATOMS; SPECTROSCOPY; ACCELERATION AB The jet-cooled laser induced fluorescence spectrum of the (B) over tilde <- <(X)over tilde> electronic transition of 2-methylvinoxy radical is assigned as a superposition of contributions from noninteracting cis and trans isomers. The spectrum of the cis isomer is identified by comparison with ab initio electronic structure calculations; both theory and experiment clearly indicate that the methyl conformation changes from the (X) over tilde state to the (B) over tilde state. Fits of both hot and cold bands to a one-dimensional torsional model yield methyl rotor barrier magnitudes of 270 +/- 20 cm(-1) in the (X) over tilde state and 200 +/- 20 cm(-1) in the (B) over tilde state. The ab initio calculations show that in the ground state the preferred conformation places one methyl CH bond in the plane of the molecular frame cis to the vicinal CC bond. Assignment of the spectrum of trans-2-methylvinoxy is more tentative because no resolved hot bands are available to corroborate the model. Our best estimate for the (B) over tilde state barrier magnitude is 60 +/- 15 cm(-1). Multireference configuration interaction calculations and coupled cluster calculations are reasonably successful in obtaining methyl torsional barriers in agreement with experiment, although high accuracy is elusive for the B state of both cis and trans isomers. By comparison with simpler cases, we infer that the Jr radical character of the B state strongly influences the methyl torsional barrier. C1 Univ Wisconsin, Dept Chem, Madison, WI 53706 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Univ Texas, Dept Chem & Biochem, Inst Theoret Chem, Austin, TX 78712 USA. RP Weisshaar, JC (reprint author), Univ Wisconsin, Dept Chem, 1101 Univ Ave, Madison, WI 53706 USA. NR 44 TC 15 Z9 15 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 NOV 9 PY 2000 VL 104 IS 44 BP 9906 EP 9913 DI 10.1021/jp002431+ PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 375QA UT WOS:000165411700013 ER PT J AU Feller, D Jordan, KD AF Feller, D Jordan, KD TI Estimating the strength of the water/single-layer graphite interaction SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID SET AB-INITIO; WATER CLUSTERS; MOLECULAR-DYNAMICS; CARBON NANOTUBES; WAVE-FUNCTIONS; HYDROGEN-BOND; LIQUID WATER; BENZENE; MODEL; COMPLEXES AB Second-order Moller-Plesset perturbation theory has been used to calculate the interaction energy between a water molecule and acenes as large as C96H24. The results of these calculations lead to an estimated value of -5.8 +/- 0.4 kcal/mol for the electronic binding energy of a water molecule with single-layer graphite. This value is comparable to the -5.0 +/- 0.1 kcal/mol binding energy of the hydrogen bonded water dimer, suggesting that the water/graphite interactions will play an important role in determining the structure of water on graphite, as well as of water inside carbon nanotubes. The present estimate of the binding energy of a water molecule to a graphite sheet is appreciably larger than those previously reported in the literature. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Univ Pittsburgh, Dept Chem, Pittsburgh, PA 15260 USA. Univ Pittsburgh, Ctr Mol & Mat Simulat, Pittsburgh, PA 15260 USA. RP Feller, D (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, MS K8-91,POB 999, Richland, WA 99352 USA. NR 46 TC 108 Z9 109 U1 2 U2 24 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 NOV 9 PY 2000 VL 104 IS 44 BP 9971 EP 9975 DI 10.1021/jp0017660 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 375QA UT WOS:000165411700021 ER PT J AU Nelsen, SF Newton, MD AF Nelsen, SF Newton, MD TI Estimation of electron transfer distances from AM1 calculations SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID TRANSITION-METAL COMPLEXES; CHARGE-TRANSFER COMPLEXES; MIXED-VALENCE COMPLEXES; ELECTROABSORPTION SPECTROSCOPY; SOLVENT REORGANIZATION; ACCEPTOR COMPOUNDS; TRANSFER KINETICS; RECOMBINATION; BIS(HYDRAZINE); SEPARATION AB We examine a simple approximate method for calculating the electron transfer (ET) distance suitable fur extracting the off-diagonal electronic coupling element (Hub) Of Marcus-Hush theory from the optical spectrum of nitrogen-centered organic intervalence radical cations. A very simple estimate of the ET distance on the adiabatic ground-state surface (d(12)(dm)) is employed. AM 1-UHF calculation of the dipole moment component in the long axis direction (mu (1)) for the radical cation using the center of mass as the origin gives the estimated d(12)(dm) (Angstrom) = 2 mu (1)(Debye)/4.8023 (eq 7). Cave and Newton's Generalized Mulliken-Hush theory equation allows calculation of the diabatic counterpart (d(ub)) in terms of d(12) and the transition dipole moment (mu (12)) obtained from the experimental intervalence optical band. These calculations indicate that d(ab) is significantly smaller than the distance between the nominal sites or charge localization, ratio 0.82-0.85 for the aromatic-bridged bis(hydrazines), 0.76-0.87 for the unsaturated-bridged bis(triarylamines), 0.74-0.79 for the saturated-bridged bis(diazenes), and 0.71-0.85 for the saturated-bridged bis(hydrazines) examined here. Furthermore, d(ab) is not very different for diastereomers that differ in relative orientation of the oxidized and reduced charge-bearing units for the aromatic-bridged compounds; experimental data corresponds to a superposition of the spectra of such isomers. There appears to be a problem with the trend of calculated ET distances as methyl groups are substituted on a benzene-1,4 -diyl bridge. The d(12)(dm) calculated is smaller for the compound with the tetramethyl-substituted bridge (DU) than that with the dimethyl-substituted bridge (XY), in contrast to the general trend in d(12) as twisting increases, and to the dipolar splitting constant for the triplet form of the dication oxidation states of these compounds. C1 Univ Wisconsin, Dept Chem, Madison, WI 53706 USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Nelsen, SF (reprint author), Univ Wisconsin, Dept Chem, 1101 Univ Ave, Madison, WI 53706 USA. NR 36 TC 72 Z9 72 U1 2 U2 8 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 NOV 9 PY 2000 VL 104 IS 44 BP 10023 EP 10031 DI 10.1021/jp002211w PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 375QA UT WOS:000165411700028 ER PT J AU Dabestani, R Higgin, J Stephenson, D Ivanov, IN Sigman, ME AF Dabestani, R Higgin, J Stephenson, D Ivanov, IN Sigman, ME TI Photophysical and photochemical processes of 2-methyl, 2-ethyl, and 2-tert-butylanthracenes on silica gel. A substituent effect study SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID SURFACE PHOTOCHEMISTRY; DRY SILICA; GEL/AIR INTERFACE; PYRENE; ACENAPHTHYLENE; ANTHRACENE; MOLECULES; PRODUCTS; SIO2; PHOTODECOMPOSITION AB The photophysics and photochemistry of 2-methylanthracene (2MA), 2-ethylanthracene (2EA), and 2-tert-butylanthracene (2TBA) adsorbed on silica was studied at a silica/air interface to determine the substituent effect on the above processes. In contrast to anthracene (AN), which forms ground state stable pairs at surface coverages as low as 1% of a monolayer, 2MA, 2EA, and 2TBA show no evidence of any ground state pairing even at high surface coverages. Diffuse reflectance and fluorescence data indicate that 2MA, 2EA, and 2TBA crystallize on the surface at higher surface coverages. Photolysis of 2MA, 2EA, and 2TBA at a silica/air interface proceeds more efficiently than photolysis of AN to produce the corresponding 9,10-endoperoxides formed by the addition of singlet molecular oxygen (type II) to the ground state molecules. Thermally unstable endoperoxides slowly decompose on silica surface to give the corresponding 9,10-quinones and other hydroxylated products of 2MA, 2EA, and 2TBA. Although photolyzed AN/silica samples show a significant amount of dimer formation at low surface coverages, no evidence of any dimer is observed in photolyzed samples of 2MA, 2EA, and 2TBA at low surface coverages. Small amount of dimers (isomeric), however, are observed in the photolyzed samples of 2MA, 2EA, and 2TBA at higher surface coverages suggesting that the crystal forms of these molecules may be involved in the dimerization process. The photolysis rate decreases as the surface coverage is increased. This behavior can be attributed to the involvement of crystals (formed at higher surface coverage) which act as a light sink to absorb the incident light without producing any net chemistry. The photolysis rate decreases by an order of magnitude in the presence of less than or equal to1 monolayer of physisorbed water. Time-resolved transient studies of excited triplet states of 2MA, 2EA, and 2TBA have revealed that triplet lifetimes are shortened on wet silica. Furthermore, the efficiency of singlet molecular oxygen formation drops significantly on wet silica. These results suggest that the decrease in photolysis rate is due to lowering of the singlet oxygen quantum yield in the presence of physisorbed water. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Dabestani, R (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, POB 2008,MS-6100, Oak Ridge, TN 37831 USA. RI ivanov, ilia/D-3402-2015 OI ivanov, ilia/0000-0002-6726-2502 NR 28 TC 18 Z9 19 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 NOV 9 PY 2000 VL 104 IS 44 BP 10235 EP 10241 DI 10.1021/jp0022555 PG 7 WC Chemistry, Physical SC Chemistry GA 375QD UT WOS:000165412000015 ER PT J AU Franzen, S Boxer, SG Dyer, RB Woodruff, WH AF Franzen, S Boxer, SG Dyer, RB Woodruff, WH TI Resonance Raman studies of heme axial ligation in H93G myoglobin SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID HISTIDINE STRETCHING MODE; CYTOCHROME-C PEROXIDASE; PORPHYRIN FORCE-FIELD; PROXIMAL LIGAND; NICKEL OCTAETHYLPORPHYRIN; SPERM WHALE; HEMOGLOBIN; SPECTROSCOPY; OXIDASE; SPECTRA AB The resonant Raman active mode identified in numerous studies as the heme iron-histidine stretch has been systematically investigated in the Raman spectrum of 15 exogenous ligands to the heme iron in the myoglobin proximal cavity mutant H93G. Mutation of the native histidine 93 of myoglobin to glycine (H93G) creates a cavity at the heme iron that can be filled with exogenous ligands. Substituted imidazoles and pyridines were introduced into the cavity at the heme iron of the deoxy ferrous H93G myoglobin by dialysis. Raman bands attributed to in-plane modes of the heme are unaffected by the change in heme-iron ligation. However, the Raman active band in the 180-250 cm(-1) region ascribed to an iron-ligand out-of-plane mode is highly dependent on the identity of the axial ligand. Information on the normal mode was obtained using isotopically labeled imidazole, pyridine, and I-methyl and 2-methyl imidazole. Relatively small isotope effects ate observed for the heme-iron ligands imidazole H93G(Im) and pyridine H93G(Pyr). We have examined models for the normal mode based on three-body, six-body, and 38-body calculations of the FG matrix. These models indicate that the potential energy distribution of the axial-ligand out-of-plane normal mode observed in the region from 180 to 245 cm(-1) has a significant contribution from iron-ligand (Fe-L) stretching (50-70%) but also from significant iron-heme doming. Using the normal coordinate analysis to correct for differences in ligand mass, we have compared the frequencies of the ligands as a function of their basicity. Although the iron-ligand force constant is linearly proportional to ligand basicity at pK(a) > 5, the correlation is less pronounced at lower pK(a). C1 N Carolina State Univ, Dept Chem, Raleigh, NC 27695 USA. Stanford Univ, Dept Chem, Stanford, CA 94305 USA. Univ Calif Los Alamos Natl Lab, Biosci & Biotechnol Grp, Los Alamos, NM 87545 USA. RP Franzen, S (reprint author), N Carolina State Univ, Dept Chem, Box 8204, Raleigh, NC 27695 USA. NR 51 TC 23 Z9 23 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD NOV 9 PY 2000 VL 104 IS 44 BP 10359 EP 10367 DI 10.1021/jp001231v PG 9 WC Chemistry, Physical SC Chemistry GA 375QD UT WOS:000165412000034 ER PT J AU Sandhu, C Donovan, J Bhattacharya, N Stampfer, M Worland, P Slingerland, J AF Sandhu, C Donovan, J Bhattacharya, N Stampfer, M Worland, P Slingerland, J TI Reduction of Cdc25A contributes to cyclin E1-Cdk2 inhibition at senescence in human mammary epithelial cells SO ONCOGENE LA English DT Article DE senescence; cell cycle; Cdc25A; p15(INK4B); cyclin E-cdk2; HMEC ID GROWTH-FACTOR-BETA; CELLULAR SENESCENCE; HUMAN FIBROBLASTS; REPLICATIVE SENESCENCE; CDK INHIBITORS; DNA-SYNTHESIS; G(1)/S TRANSITION; DEPENDENT KINASES; PROTEIN-KINASE; GENE STATUS AB Replicative senescence may be an important tumor suppressive mechanism for human cells. We investigated the mechanism of cell cycle arrest at senescence in human mammary epithelial cells (HMECs) that have undergone a period of 'self-selection', and as a consequence exhibit diminished p16(INK4A) levels. As HMECs approached senescence, the proportion of cells with a 2N DNA content increased and that in S phase decreased progressively. Cyclin D1-cdk4, cyclin E-cdk2 and cyclin A-cdk2 activities were not abruptly inhibited, but rather diminished steadily with increasing population age. In contrast to observations in fibroblast, p21(Cip1) was not increased at senescence in HMECs. There was no increase in p27(Kip1) levels nor in KIP association with targets cdks. While p15(INK4B) and its binding to both cdk4 and cdk6 increased with increasing passage, some cyclin D1-bound cdk4 and cdk6 persisted in senescent cells, whose inhibition could not be attributed to p15(INK4B). The inhibition of cyclin E-cdk2 in senescent HMECs was accompanied by increased inhibitory phosphorylation of cdk2, in association with a progressive loss of Cdc25A. Recombinant Cdc25A strongly reactivated cyclin E-cdk2 from senescent HMECs suggesting that reduction of Cdc25A contributes to cyclin E-cdk2 inhibition and G1 arrest at senescence. Although ectopic expression of Cdc25A failed to extend the lifespan of HMECs, the exogenous Cdc25A appeared to lack activity in these cells, since it neither shortened the G1-to-S phase interval nor activated cyclin E-cdk2. In contrast, in the breast cancer-derived MCF-7 line, Cdc25A overexpression increased both cyclin E-cdk2 activity and the S phase fraction. Thus, mechanisms leading to HMEC immortalization may involve not only the re-induction of Cdc25A expression, but also activation of this phosphatase. C1 Sunnybrook & Womens Coll, Hlth Sci Ctr, Div Canc Res, Toronto, ON M4N 3M5, Canada. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Mitotix Inc, Cambridge, MA 02139 USA. RP Slingerland, J (reprint author), Sunnybrook & Womens Coll, Hlth Sci Ctr, Div Canc Res, S-238,2075 Bayview Ave, Toronto, ON M4N 3M5, Canada. FU NCI NIH HHS [CA-24844] NR 71 TC 37 Z9 42 U1 0 U2 0 PU NATURE PUBLISHING GROUP PI BASINGSTOKE PA HOUNDMILLS, BASINGSTOKE RG21 6XS, HAMPSHIRE, ENGLAND SN 0950-9232 J9 ONCOGENE JI Oncogene PD NOV 9 PY 2000 VL 19 IS 47 BP 5314 EP 5323 DI 10.1038/sj.onc.1203908 PG 10 WC Biochemistry & Molecular Biology; Oncology; Cell Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Oncology; Cell Biology; Genetics & Heredity GA 373RH UT WOS:000165302300002 PM 11103932 ER PT J AU Holden, J Benczer-Koller, N Jakob, G Kumbartzki, G Mertzimekis, TJ Speidel, KH Macchiavelli, A McMahan, M Phair, L Maier-Komor, P Stuchbery, AE Rogers, WF Davies, AD AF Holden, J Benczer-Koller, N Jakob, G Kumbartzki, G Mertzimekis, TJ Speidel, KH Macchiavelli, A McMahan, M Phair, L Maier-Komor, P Stuchbery, AE Rogers, WF Davies, AD TI Evidence for 2f(7/2) neutron strength in the low energy structure of Nd-144,Nd-146,Nd-148,Nd-150 isotopes SO PHYSICS LETTERS B LA English DT Article ID MAGNETIC-MOMENT MEASUREMENTS; NUCLEI; STATES AB The g factors of the 4(1)(+) and 6(1)(+) states in Nd-144.148, the 4(1)(+) state in Nd-146 and the 4(1)(+), 6(1)(+), 8(1)(+) and 10(1)(+) states in Nd-150 have been measured fur the first time by projectile Coulomb excitation combined with the transient field technique. The g factors of the 2(1)(+) states in Nd-144,Nd-146,Nd-148,Nd-150 have been remeasured with very high precision. A pronounced transition in the structure of these isotopes occurs as neutrons are removed from the rotational Nd-150 and shell closure at N = 82 is approached. The g factors unambiguously reflect the increasing strength of the (2f(7/2))(nu)(n) configuration. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Rutgers State Univ, Dept Phys & Astron, New Brunswick, NJ 08903 USA. Univ Bonn, Inst Strahlen & Kernphys, D-5300 Bonn, Germany. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Tech Univ Munich, D-8000 Munich, Germany. Australian Natl Univ, Dept Nucl Phys, Canberra, ACT 0200, Australia. Westmont Coll, Santa Barbara, CA 93108 USA. RP Benczer-Koller, N (reprint author), Rutgers State Univ, Dept Phys & Astron, New Brunswick, NJ 08903 USA. RI Mertzimekis, Theo/A-3287-2008 OI Mertzimekis, Theo/0000-0001-9191-7903 NR 27 TC 23 Z9 23 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 NOV 9 PY 2000 VL 493 IS 1-2 BP 7 EP 11 DI 10.1016/S0370-2693(00)01136-9 PG 5 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 376WJ UT WOS:000165479500002 ER PT J AU Anthony, PL Arnold, RG Averett, T Band, HR Berisso, MC Borel, H Bosted, PE Bultmann, SL Buenerd, M Chupp, T Churchwell, S Court, GR Crabb, D Day, D Decowski, P DePietro, P Erbacher, R Erickson, R Feltham, A Fonvieille, H Frlez, E Gearhart, R Ghazikhanian, V Gomez, J Griffioen, KA Harris, C Houlden, MA Hughes, EW Hyde-Wright, CE Igo, G Incerti, S Jensen, J Johnson, JR King, PM Kolomensky, YG Kuhn, SE Lindgren, R Lombard-Nelsen, RM Marroncle, J McCarthy, J McKee, P Meyer, W Mitchell, GS Mitchell, J Olson, M Penttila, S Peterson, GA Petratos, GG Pitthan, R Pocanic, D Prepost, R Prescott, C Qin, LM Raue, BA Reyna, D Rochester, LS Rock, S Rondon-Aramayo, OA Sabatie, F Sick, I Smith, T Sorrell, L Staley, F St Lorant, S Stuart, LM Szalata, Z Terrien, Y Tobias, A Todor, L Toole, T Trentalange, S Walz, D Welsh, RC Wesselmann, FR Wright, TR Young, CC Zeier, M Zhu, H Zihlmann, B AF Anthony, PL Arnold, RG Averett, T Band, HR Berisso, MC Borel, H Bosted, PE Bultmann, SL Buenerd, M Chupp, T Churchwell, S Court, GR Crabb, D Day, D Decowski, P DePietro, P Erbacher, R Erickson, R Feltham, A Fonvieille, H Frlez, E Gearhart, R Ghazikhanian, V Gomez, J Griffioen, KA Harris, C Houlden, MA Hughes, EW Hyde-Wright, CE Igo, G Incerti, S Jensen, J Johnson, JR King, PM Kolomensky, YG Kuhn, SE Lindgren, R Lombard-Nelsen, RM Marroncle, J McCarthy, J McKee, P Meyer, W Mitchell, GS Mitchell, J Olson, M Penttila, S Peterson, GA Petratos, GG Pitthan, R Pocanic, D Prepost, R Prescott, C Qin, LM Raue, BA Reyna, D Rochester, LS Rock, S Rondon-Aramayo, OA Sabatie, F Sick, I Smith, T Sorrell, L Staley, F St Lorant, S Stuart, LM Szalata, Z Terrien, Y Tobias, A Todor, L Toole, T Trentalange, S Walz, D Welsh, RC Wesselmann, FR Wright, TR Young, CC Zeier, M Zhu, H Zihlmann, B CA E155 Collaboration TI Measurements of the Q(2)-dependence of the proton and neutron spin structure functions g(1)(p) and g(1)(n) SO PHYSICS LETTERS B LA English DT Article ID DEEP-INELASTIC-SCATTERING; SUM-RULE; POLARIZED NUCLEONS; PRECISION-MEASUREMENT; DEUTERON; LEPTONS; ELECTROPRODUCTION; BJORKEN; G(2) AB The structure functions g(1)(p) and g(1)(n) have been measured over the range 0.014 < x < 0.9 and 1 < Q(2) < 40 GeV2 using deep-inelastic scattering of 48 GeV longitudinally polarized electrons from polarized protons and deuterons. We find that the Q(2) dependence of g(1)(p) (g(1)(n)) at fixed x is very similar to that of the spin-averaged structure function F-1(p) (F-1(n)). From an NLO QCD fit to all available data we And Gamma (p)(1) - Gamma (n)(1) = 0.176 +/- 0.003 +/- 0.007 at Q(2) = 5 GeV2, in agreement with the Bjorken sum rule prediction of 0.182 +/- 0.005. (C) 2000 Published by Elsevier Science B.V. C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. American Univ, Washington, DC 20016 USA. Univ Basel, Inst Phys, CH-4056 Basel, Switzerland. Univ Blaise Pascal, LPC, IN2P3, CNRS, F-63170 Aubiere, France. Ruhr Univ Bochum, D-4630 Bochum, Germany. CALTECH, Pasadena, CA 91125 USA. Univ Calif Los Angeles, Los Angeles, CA 90095 USA. CEA Saclay, DAPNIA, Serv Phys Nucl, F-91191 Gif Sur Yvette, France. Florida Int Univ, Miami, FL 33199 USA. Kent State Univ, Kent, OH 44242 USA. Univ Liverpool, Liverpool L69 3BX, Merseyside, England. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Massachusetts, Amherst, MA 01003 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Old Dominion Univ, Norfolk, VA 23529 USA. Smith Coll, Northampton, MA 01063 USA. Stanford Univ, Stanford, CA 94305 USA. Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. Univ Virginia, Charlottesville, VA 22901 USA. Coll William & Mary, Williamsburg, VA 23187 USA. Univ Wisconsin, Madison, WI 53706 USA. RP Anthony, PL (reprint author), Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RI Averett, Todd/A-2969-2011; Rondon Aramayo, Oscar/B-5880-2013; Frlez, Emil/B-6487-2013; Day, Donal/C-5020-2015; Kolomensky, Yury/I-3510-2015; Sabatie, Franck/K-9066-2015; OI Day, Donal/0000-0001-7126-8934; Kolomensky, Yury/0000-0001-8496-9975; Sabatie, Franck/0000-0001-7031-3975; Wesselmann, Frank/0000-0001-7834-7977; Hyde, Charles/0000-0001-7282-8120; King, Paul/0000-0002-3448-2306; Incerti, Sebastien/0000-0002-0619-2053 NR 34 TC 240 Z9 240 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 NOV 9 PY 2000 VL 493 IS 1-2 BP 19 EP 28 DI 10.1016/S0370-2693(00)01014-5 PG 10 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 376WJ UT WOS:000165479500004 ER PT J AU Afnan, IR Bissey, F Gomez, J Katramatou, AT Melnitchouk, W Petratos, GG Thomas, AW AF Afnan, IR Bissey, F Gomez, J Katramatou, AT Melnitchouk, W Petratos, GG Thomas, AW TI Neutron structure function and A=3 mirror nuclei SO PHYSICS LETTERS B LA English DT Article ID DEEP-INELASTIC-SCATTERING; PARTON DISTRIBUTIONS; CROSS-SECTIONS; LARGE-X; ELECTRON-SCATTERING; FORM-FACTORS; QCD ANALYSIS; DEUTERON; PROTON; BINDING AB We investigate deep inelastic scattering from He-3 and H-3 within a conventional convolution treatment of binding and Fermi motion effects. Using realistic Faddeev wave functions together with a nucleon spectral function, we demonstrate that the free neutron structure function can be extracted in deep-inelastic scattering from A = 3 mirror nuclei, with nuclear effects canceling to within 2% for x less than or similar to 0.85. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Adelaide, Special Res Ctr Subatom Struct Matter, Adelaide, SA 5005, Australia. Univ Adelaide, Dept Phys & Math Phys, Adelaide, SA 5005, Australia. Flinders Univ S Australia, Sch Phys Sci, Bedford Pk, SA 5042, Australia. Univ Clermont Ferrand, Phys Corpusculaire Lab, CNRS, IN2P3, F-63177 Clermont Ferrand, France. Jefferson Lab, Newport News, VA 23606 USA. Kent State Univ, Kent, OH 44242 USA. RP Melnitchouk, W (reprint author), Univ Adelaide, Special Res Ctr Subatom Struct Matter, Adelaide, SA 5005, Australia. EM wmelnitc@nlab.org RI Thomas, Anthony/G-4194-2012 OI Thomas, Anthony/0000-0003-0026-499X NR 60 TC 44 Z9 44 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 NOV 9 PY 2000 VL 493 IS 1-2 BP 36 EP 42 DI 10.1016/S0370-2693(00)01012-1 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 376WJ UT WOS:000165479500006 ER PT J AU Nierste, U Plehn, T AF Nierste, U Plehn, T TI Probing light sbottoms with B decays SO PHYSICS LETTERS B LA English DT Article DE supersymmetry; squark; beauty; interpretation of experimental results ID SCALAR QUARK DECAYS; QCD CORRECTIONS; SUPERSYMMETRIC PARTICLES; TOP-QUARK; SEARCH; COLLISIONS; MASS; UNIFICATION; COLLIDERS; ENERGIES AB We discuss recently reported experimental hints for a bottom squark with mass around 3.5 GeV decaying as (b) over tilde --> cl<()over tilde>*. We correlate the sbottom lifetime with the dccay rates for b --> (b) over tilde nu<()over tilde>* and b --> (b) over tilde<()over bar><()over tilde> in the framework of a minimal supersymmetric model extended by right-handed (s)neutrinos. Confronting our results with the well-measured semileptonic branching ratio of B mesons we conclude that the light sbottom interpretation of the experimental anomalies is ruled out, unless m(b) less than or equal to m((b) over tilde) + m(<()over bar>). (C) 2000 Published by Elsevier Science B.V. C1 Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Plehn, T (reprint author), Univ Wisconsin, Dept Phys, 1150 Univ Ave, Madison, WI 53706 USA. NR 35 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 NOV 9 PY 2000 VL 493 IS 1-2 BP 104 EP 112 DI 10.1016/S0370-2693(00)01122-9 PG 9 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 376WJ UT WOS:000165479500016 ER PT J AU Davoudiasl, H Hewett, JL Rizzo, TG AF Davoudiasl, H Hewett, JL Rizzo, TG TI The g-2 of the muon in localized gravity models SO PHYSICS LETTERS B LA English DT Article ID KALUZA-KLEIN STATES; EXTRA DIMENSIONS; COLLIDERS; TEV; SUPERSYMMETRY; SUPERSTRINGS; MILLIMETER; HIERARCHY; BREAKING; SIGNALS AB The (g - 2) of the muon is well known to be an important model building constraint on theories beyond the Standard Model. In this Letter, we examine the contributions to (g - 2)mu arising in the Randall-Sundrum model of localized gravity fur the case where the Standard Model gauge fields and fermions are both in the hulk. Using the current experimental world average measurement for (S - 2)mu, we find that strong constraints can be placed on the mass of the lightest gauge Kaluza-Klein excitation For a narrow part of the allowed range of the assumed universal 5-dimensional fermion mass parameter, I,. However, employing both perturbativity and fine-tuning constraints we find that we can further restrict the allowed range of the parameter nu to only one fourth of its previous size. The scenario with the SM in the RS bulk is thus tightly constrained, being viable for only a small region of the parameter space. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Hewett, JL (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 42 TC 38 Z9 38 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 NOV 9 PY 2000 VL 493 IS 1-2 BP 135 EP 141 DI 10.1016/S0370-2693(00)01132-1 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 376WJ UT WOS:000165479500020 ER PT J AU Gelis, F AF Gelis, F TI A simple criterion for effects beyond hard thermal loops SO PHYSICS LETTERS B LA English DT Article DE finite temperature; perturbation theory; multiple scatterings ID CLASSICAL TRANSPORT-THEORY; QUARK-GLUON PLASMA; PHOTON PRODUCTION-RATE; HOT GAUGE-THEORIES; LADDER GRAPHS; FINITE-TEMPERATURE; DAMPING RATE; QCD; DYNAMICS; CANCELLATION AB Thermal amplitudes with ultrasoft momenta, which are not accessible by standard methods of perturbation theory, have recently attracted a lot of interest. However, the comparison of external momenta with the ultrasoft scale g(2)T In(1/g) is a too crude criterion, since amplitudes with hard external momenta can also be non perturbative, if these momenta are close enough to the light-cone. In this letter, I give a more refined criterion to decide if an amplitude is non perturbative, that applies to all situations. In physical terms, this condition states that non-perturbative: effects appear if the particles running in loops have to travel distances larger than their mean free path. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. EM gelis@bnl.gov NR 35 TC 5 Z9 5 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 NOV 9 PY 2000 VL 493 IS 1-2 BP 182 EP 188 DI 10.1016/S0370-2693(00)01130-8 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 376WJ UT WOS:000165479500027 ER PT J AU Dhar, M Webb, LS Smith, L Hauser, L Johnson, D West, DB AF Dhar, M Webb, LS Smith, L Hauser, L Johnson, D West, DB TI A novel ATPase on mouse chromosome 7 is a candidate gene for increased body fat SO PHYSIOLOGICAL GENOMICS LA English DT Article DE mouse chromosome 7; quantitative trait loci; adiposity ID DILUTION P LOCUS; DIETARY OBESITY; AGOUTI GENE; SEQUENCES; SUBFAMILY; MUTATIONS; TRAIT; MODEL; RATS; ACID AB A region of mouse chromosome 7, just distal to the pink-eyed (p) dilution locus, contains a gene or genes, which we have named p-locus-associated obesity (plo1), affecting body fat. Mice heterozygous for the most distally extending chromosomal deletions of this region have nearly double the body fat of mice when the deletion is inherited maternally as when it is inherited paternally. We have physically mapped the 1-Mb critical region, which lies between the Gabrb3 and Ube3a/ Ipw genes, and DNA sequencing has localized a new member of the third subfamily of P-type ATPases to the minimal region specifying the trait. This gene, which we have called p-locus fat-associated ATPase ( pfatp) is differentially expressed in human and mouse tissues with predominant expression in the testis and lower levels of expression in adipose tissue and other organs. We propose this ATPase as the prime candidate for the gene at the plo1 locus modulating body fat content in the mouse. The unusual inheritance pattern of this phenotype suggests either genomic imprinting, known to occur in other local genes (Ube3a, Ipw), or an effect of maternal haploinsufficiency during pregnancy or lactation on body fat in the progeny. C1 Alameda Labs, Pfizer Global Res & Dev, Alameda, CA 94502 USA. Univ Tennessee, Grad Sch Genome Sci & Technol, Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. Lawrence Berkeley Lab, Dept Mol Med, Donner Lab, Berkeley, CA 94720 USA. RP West, DB (reprint author), Alameda Labs, Pfizer Global Res & Dev, 1501 Harbor Bay Pkwy, Alameda, CA 94502 USA. EM david.west@w1.com RI Hauser, Loren/H-3881-2012 FU NIDDK NIH HHS [DK-45895, DK-53393] NR 39 TC 46 Z9 47 U1 0 U2 1 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 1094-8341 J9 PHYSIOL GENOMICS JI Physiol. Genomics PD NOV 9 PY 2000 VL 4 IS 1 BP 93 EP 100 PG 8 WC Cell Biology; Genetics & Heredity; Physiology SC Cell Biology; Genetics & Heredity; Physiology GA 371RV UT WOS:000165192700011 PM 11074018 ER PT J AU Dunning, TH Peterson, KA AF Dunning, TH Peterson, KA TI Approximating the basis set dependence of coupled cluster calculations: Evaluation of perturbation theory approximations for stable molecules SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID TOTAL ATOMIZATION ENERGIES; ELECTRIC QUADRUPOLE-MOMENT; QUARTIC FORCE-FIELD; AB-INITIO; WAVE-FUNCTIONS; BENCHMARK CALCULATIONS; GAUSSIAN-2 THEORY; FIRST-ROW; VIBRATIONAL FREQUENCIES; CORRELATED CALCULATIONS AB The coupled cluster CCSD(T) method provides a theoretically sound, accurate description of the electronic structure of a wide range of molecules. To obtain accurate results, however, very large basis sets must be used. Since the computational cost of CCSD(T) calculations formally increases with the seventh power of the number of basis functions (N-7), the CCSD(T) method can only be applied to a restricted range of molecules. In this work we show that the basis set dependence of the CCSD(T) method is well described by perturbation theory. Starting with CCSD(T)/aug-cc-pVTZ calculations, use of the MP3 method to simulate the effect of increasing the basis set to aug-cc-pV5Z leads to average absolute errors, relative to the full CCSD(T)/aug-cc-pV5Z calculations, of less than +/-0.4 kcal/mol (D-e), +/-0.0002 A (r(e)), +/-2 cm(-1) (omega (e)), 0.1 kcal/mol (IPe), and 0.2 kcal/mol (EA(e)) for the test set of diatomic molecules considered here. Although the corresponding MP2 approximation does not provide this high level of accuracy, it also should be useful for many molecular studies. When properly implemented, the savings in computer time should be significant since the MP3 method formally scales as N-6, while the MP2 method scales as only N-5. (C) 2000 American Institute of Physics. [S0021-9606(00)31942-0]. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Dunning, TH (reprint author), US DOE, Off Sci, 19901 Germantown Rd, Germantown, MD 20874 USA. NR 56 TC 46 Z9 46 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD NOV 8 PY 2000 VL 113 IS 18 BP 7799 EP 7808 AR PII [S0021-9606(00)31942-0] DI 10.1063/1.1316041 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 369BF UT WOS:000090151400012 ER PT J AU Liu, JB Hochlaf, M Ng, CY AF Liu, JB Hochlaf, M Ng, CY TI Pulsed field ionization-photoelectron bands for CO2+(A (2)Pi(u) and B (2)Sigma(+)(u)) in the energy range of 17.2-19.0 eV: An experimental and theoretical study SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID HIGH-RESOLUTION; THRESHOLD PHOTOELECTRON; SYNCHROTRON-RADIATION; EMISSION-SPECTRUM; ROVIBRONIC SPECTRUM; VIBRONIC STRUCTURE; CARBON-DIOXIDE; SPECTROSCOPY; PHOTOIONIZATION; STATES AB The vacuum ultraviolet (VUV) pulsed field ionization-photoelectron (PFI-PE) spectra for CO2 have been measured in the energy range of 17.2-19.0 eV, showing complex vibronic structures for the CO2+(A (2)Pi (u) and B (2)Sigma (+)(u)) states. The PFI-PE spectra for CO2+(A (2)Pi (u) and B (2)Sigma (+)(u)) are dominated by the upsilon (+)(1) (symmetric stretching) vibrational progressions, and weak bands due to excitation of both even and odd quanta of the upsilon (+)(2) (bending) and upsilon (+)(3) (antisymmetric stretching) modes are observed in the VUV-PFI-PE spectra. The simulation of rotational contours resolved in the PFI-PE vibronic bands associated with excitation to CO2+(A (2)Pi (3/2,1/2u);upsilon (+)(1)=0-5,upsilon (+)(2)=0,upsilon (+)(3)=0) and CO2+(B (2)Sigma (+)(u);0,0,0) has yielded accurate ionization energies for the formation of these states from CO2(X (1)Sigma (+)(g)). Three-dimensional potential energy functions (PEFs) for CO2+(B (2)Sigma (+)(u)) have also been generated theoretically using the complete active space self-consistent field and internally contracted multireference configuration interaction methods. Based on these PEFs, vibrational energy levels for CO2+(B (2)Sigma (+)(u)), together with the Franck-Condon factors for their formation from CO2(X (1)Sigma (+)(g)), have been calculated. With the guide of these theoretical predictions, the vibrational bands resolved in the PFI-PE spectrum for CO2+(B (2)Sigma (+)(u)) have been satisfactorily assigned. This assignment reveals the nature of many vibrational PFI-PE bands as originated from anharmonic resonance interactions and members of Fermi polyads. (C) 2000 American Institute of Physics. [S0021-9606(00)00442-6]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Marne La Vallee, Theoret Chem Grp, F-77454 Marne La Vallee 2, France. Iowa State Univ, Ames Lab, US DOE, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP Ng, CY (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. NR 51 TC 33 Z9 34 U1 1 U2 8 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD NOV 8 PY 2000 VL 113 IS 18 BP 7988 EP 7999 DI 10.1063/1.1314354 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 369BF UT WOS:000090151400035 ER PT J AU Chialvo, AA Cummings, PT Simonson, JM AF Chialvo, AA Cummings, PT Simonson, JM TI H3O+/Cl- ion-pair formation in high-temperature aqueous solutions SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MOLECULAR-DYNAMICS SIMULATION; THERMODYNAMIC PROPERTIES; SUPERCRITICAL WATER; HYDROCHLORIC-ACID; POLAR-SOLVENT; ASSOCIATION; HCL; DISSOCIATION; PRESSURES; NACL AB The radial profiles of the mean force and corresponding potential of mean force for the Cl-. . .H3O+ pair are determined by constraint molecular dynamics of an infinitely dilute near-critical aqueous solution, as described by the SPC/E water model and either the Gertner-Hynes or the Kusaka hydronium model. These profiles are used to test the prediction of a continuum primitive model, and to predict the ion-pair association constant. The reliability of these intermolecular potential models is assessed by comparing the predicted association constants with those determined experimentally by conductance and solubility measurements. This comparison suggests that the most accurate experimental data available for the association constant of HCl fall between the predictions of the two models, and tends to support the superiority of the Gertner-Hynes over the Kusaka hydronium model. Moreover, the simulation results allow a quick test of the reliability of the simple continuum dielectric model to represent the solvation behavior of the ion-pair in solution. (C) 2000 American Institute of Physics. [S0021-9606(00)50542-X]. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, High Temp Aqueous Chem Grp, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Chem Engn, Knoxville, TN 37996 USA. Univ Tennessee, Dept Chem & Comp Sci, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. RP Chialvo, AA (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, High Temp Aqueous Chem Grp, Oak Ridge, TN 37831 USA. RI Cummings, Peter/B-8762-2013; OI Cummings, Peter/0000-0002-9766-2216; Chialvo, Ariel/0000-0002-6091-4563 NR 60 TC 34 Z9 34 U1 0 U2 12 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD NOV 8 PY 2000 VL 113 IS 18 BP 8093 EP 8100 DI 10.1063/1.1314869 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 369BF UT WOS:000090151400046 ER PT J AU Kopta, S Salmeron, M AF Kopta, S Salmeron, M TI The atomic scale origin of wear on mica and its contribution to friction SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID CHAIN-LENGTH DEPENDENCE; FORCE MICROSCOPY; ULTRAHIGH-VACUUM; SLIDING FRICTION; SURFACE; TRIBOLOGY; FILMS; GOLD AB Atomic force microscopy is used to show that production of surface defects at the interface of rubbing solids is an important mechanism of energy dissipation in friction. Using mica and Si-tips, we demonstrate that defects produced by the rupture of Si-O bonds at the surface, which are not visible in contact mode AFM images, have a noticeable contribution to friction. When defects accumulate beyond a critical concentration, they grow to form visible wear scars similar to2 Angstrom deep at first and deeper holes later. The contribution of defect production to friction is explained by a simple model, which is based on the stress-induced enhancement of the rate of thermal defect production. (C) 2000 American Institute of Physics. [S0021-9606(00)70342-4]. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Basel, Inst Phys, Basel, Switzerland. RP Salmeron, M (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. NR 24 TC 61 Z9 61 U1 2 U2 16 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD NOV 8 PY 2000 VL 113 IS 18 BP 8249 EP 8252 DI 10.1063/1.1314376 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 369BF UT WOS:000090151400065 ER PT J AU Almgren, AS Bell, JB Crutchfield, WY AF Almgren, AS Bell, JB Crutchfield, WY TI Approximate projection methods: Part I. Inviscid analysis SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article DE projection method; approximate projection; incompressible flow ID NAVIER-STOKES EQUATIONS; STATES; FLOW AB The use of approximate projection methods for modeling low Mach number flows avoids many of the numerical complications associated with exact projection methods, but introduces additional design choices in developing a robust algorithm. In this paper we first explore these design choices in the setting of inviscid incompressible ow using several computational examples. We then develop a framework for analyzing the behavior of the different design variations and use that analysis to explain the features observed in the computations. As part of this work we introduce a new variation of the approximate projection algorithm that combines the advantages of several of the previous versions. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Almgren, AS (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, MS 50A-1148, Berkeley, CA 94720 USA. NR 20 TC 55 Z9 56 U1 1 U2 5 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 NOV 8 PY 2000 VL 22 IS 4 BP 1139 EP 1159 DI 10.1137/S1064827599357024 PG 21 WC Mathematics, Applied SC Mathematics GA 375BL UT WOS:000165379600001 ER PT J AU Khamayseh, A Hansen, G AF Khamayseh, A Hansen, G TI Quasi-orthogonal grids with impedance matching SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article DE quasi-conformal mapping; elliptic grid generation; grid orthogonality; impedance matching ID GENERATION AB An elliptic, quasi-orthogonal grid generation system is formulated based on quasi-conformal mapping for arbitrary anisotropic (long and skinny) regions. The resulting system is a generalization of the well-known elliptic grid generation system derived from conformal mapping. Coupled with the grid generation system, the impedance-matching principle describes a methodology for preserving the discrete accuracy of the simulation, both internal to the domain and near internal geometric interfaces. Empirically, satisfying the impedance principle tends to minimize mesh effects on the solution results; meshes that are impedance-matched tend to reduce or eliminate spurious wave reflection and/or attenuation at internal interfaces. The resulting grid generation system is used to construct impedance-matched quasi-orthogonal grids on domains containing internal geometric constraints given an algebraic grid and a grid impedance function as initial conditions. C1 Univ Calif Los Alamos Natl Lab, Div Appl Phys, Los Alamos, NM 87545 USA. RP Khamayseh, A (reprint author), Univ Calif Los Alamos Natl Lab, Div Appl Phys, MS F645, Los Alamos, NM 87545 USA. NR 13 TC 7 Z9 7 U1 0 U2 0 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 NOV 8 PY 2000 VL 22 IS 4 BP 1220 EP 1237 DI 10.1137/S1064827599358613 PG 18 WC Mathematics, Applied SC Mathematics GA 375BL UT WOS:000165379600005 ER PT J AU Benzi, M Cullum, JK Tuma, M AF Benzi, M Cullum, JK Tuma, M TI Robust approximate inverse preconditioning for the conjugate gradient method SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article DE sparse linear systems; finite element matrices; preconditioned conjugate gradients; factorized sparse approximate inverses; incomplete conjugation; stabilized AINV; diagonally compensated reduction ID LINEAR-SYSTEMS; MATRIX; ALGORITHM AB We present a variant of the AINV factorized sparse approximate inverse algorithm which is applicable to any symmetric positive definite matrix. The new preconditioner is breakdown-free and, when used in conjunction with the conjugate gradient method, results in a reliable solver for highly ill-conditioned linear systems. We also investigate an alternative approach to a stable approximate inverse algorithm, based on the idea of diagonally compensated reduction of matrix entries. The results of numerical tests on challenging linear systems arising from finite element modeling of elasticity and diffusion problems are presented. C1 Univ Calif Los Alamos Natl Lab, Comp Res & Applicat Grp CIC3, Los Alamos, NM 87545 USA. Acad Sci Czech Republ, Inst Comp Sci, Prague 18207 8, Czech Republic. RP Benzi, M (reprint author), Emory Univ, Dept Math & Comp Sci, Atlanta, GA 30322 USA. RI Tuma, Miroslav/A-5946-2014 OI Tuma, Miroslav/0000-0003-2808-6929 NR 38 TC 86 Z9 91 U1 0 U2 6 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 NOV 8 PY 2000 VL 22 IS 4 BP 1318 EP 1332 DI 10.1137/S1064827599356900 PG 15 WC Mathematics, Applied SC Mathematics GA 375BL UT WOS:000165379600008 ER PT J AU Kurganov, A Levy, D AF Kurganov, A Levy, D TI A third-order semidiscrete central scheme for conservation laws and convection-diffusion equations SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article DE hyperbolic systems; convection-diffusion equations; central difference schemes; high-order accuracy; nonoscillatory schemes; weighted essentially nonoscillatory reconstruction ID NONOSCILLATORY CENTRAL SCHEMES; SHOCK-CAPTURING SCHEMES; BURGERS-TYPE EQUATIONS; EFFICIENT IMPLEMENTATION; HYPERBOLIC SYSTEMS; HIGH-RESOLUTION; GRIDS AB We present a new third-order, semidiscrete, central method for approximating solutions to multidimensional systems of hyperbolic conservation laws, convection-diffusion equations, and related problems. Our method is a high-order extension of the recently proposed second-order, semidiscrete method in [A. Kurgonov and E. Tadmor, J. Comput Phys., 160 (2000) pp. 241-282]. The method is derived independently of the specfic piecewise polynomial reconstruction which is based on the previously computed cell-averages. We demonstrate our results by focusing on the new third-order central weighted essentially nonoscillatory (CWENO) reconstruction presented in [D. Levy, G. Puppo, and G. Russo, SIAM J. Sci. Comput., 21 (1999), pp. 294-322]. The numerical results we present show the desired accuracy, high resolution, and robustness of our method. C1 Univ Michigan, Dept Math, Ann Arbor, MI 48109 USA. Univ Calif Berkeley, Dept Math, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Univ Michigan, Dept Math, Ann Arbor, MI 48109 USA. EM kurganov@math.lsa.umich.edu; dlevy@math.berkeley.edu RI Kurganov, Alexander/H-8789-2013 OI Kurganov, Alexander/0000-0003-0231-986X NR 35 TC 137 Z9 153 U1 1 U2 15 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 1064-8275 EI 1095-7197 J9 SIAM J SCI COMPUT JI SIAM J. Sci. Comput. PD NOV 8 PY 2000 VL 22 IS 4 BP 1461 EP 1488 DI 10.1137/S1064827599360236 PG 28 WC Mathematics, Applied SC Mathematics GA 375BL UT WOS:000165379600014 ER PT J AU Pedraza, AJ Fowlkes, JD Lowndes, DH AF Pedraza, AJ Fowlkes, JD Lowndes, DH TI Laser ablation and column formation in silicon under oxygen-rich atmospheres SO APPLIED PHYSICS LETTERS LA English DT Article ID IRRADIATION AB The microstructure formed at the surface of silicon by cumulative pulsed-laser irradiation in oxygen-rich atmospheres consists of an array of microcolumns surrounded by microcanyons and microholes. Formation of SiOx at the exposed surface of silicon is most likely responsible for the occurrence of etching/ablation that causes the continuous deepening of canyons and holes. The growth mechanism of columns that is supported by the experimental evidence presented here is a process in which the columns are fed at their tips by the silicon-rich ablation plasma produced during pulsed-laser irradiation. (C) 2000 American Institute of Physics. [S0003-6951(00)05645-X]. C1 Univ Tennessee, Dept Mat Sci & Engn, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Pedraza, AJ (reprint author), Univ Tennessee, Dept Mat Sci & Engn, Knoxville, TN 37996 USA. NR 12 TC 30 Z9 30 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD NOV 6 PY 2000 VL 77 IS 19 BP 3018 EP 3020 DI 10.1063/1.1324732 PG 3 WC Physics, Applied SC Physics GA 369MG UT WOS:000165069500026 ER PT J AU Suemune, I Uesugi, K Walukiewicz, W AF Suemune, I Uesugi, K Walukiewicz, W TI Role of nitrogen in the reduced temperature dependence of band-gap energy in GaNAs SO APPLIED PHYSICS LETTERS LA English DT Article ID VAPOR-PHASE EPITAXY; ALLOYS AB We have observed a significant reduction in the temperature dependence of the absorption-edge energy in GaNxAs1-x alloys with x <0.04. The effect has been analyzed in terms of the recently introduced band anticrossing model that considers a coupling of the temperature-independent localized states of substitutional nitrogen atoms and the temperature-dependent extended states of GaAs. The model explains very well the alloy composition and the temperature dependence of the absorption-edge energy. We also compare the parameters that determine the temperature dependence of the band-gap energies in GaNAs and GaInNAs alloys. (C) 2000 American Institute of Physics. [S0003-6951(00)00545-3]. C1 Hokkaido Univ, Res Inst Elect Sci, Sapporo, Hokkaido 0600812, Japan. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Hokkaido Univ, Res Inst Elect Sci, Sapporo, Hokkaido 0600812, Japan. EM isuemune@es.hokudai.ac.jp RI Suemune, Ikuo/B-3133-2012 OI Suemune, Ikuo/0000-0002-9967-6865 NR 18 TC 101 Z9 103 U1 0 U2 11 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0003-6951 EI 1077-3118 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD NOV 6 PY 2000 VL 77 IS 19 BP 3021 EP 3023 AR PII [S0003-6951(00)00545-3] DI 10.1063/1.1322633 PG 3 WC Physics, Applied SC Physics GA 369MG UT WOS:000165069500027 ER PT J AU Lettieri, J Zurbuchen, MA Jia, Y Schlom, DG Streiffer, SK Hawley, ME AF Lettieri, J Zurbuchen, MA Jia, Y Schlom, DG Streiffer, SK Hawley, ME TI Epitaxial growth of SrBi2Nb2O9 on (110) SrTiO3 and the establishment of a lower bound on the spontaneous polarization of SrBi2Nb2O9 SO APPLIED PHYSICS LETTERS LA English DT Article ID SRBI2TA2O9 THIN-FILMS; BISMUTH TITANATE; AXIS AB Epitaxial SrBi2Nb2O9 thin films have been grown on (110) SrTiO3 substrates by pulsed laser deposition. Four-circle x-ray diffraction and transmission electron microscopy reveal nearly phase pure epitaxial films with the c axis of the films at 45 degrees with respect to the substrate normal. Electrical characterization is presented for films grown on epitaxial SrRuO3 electrodes. The low-field relative permittivity was 235, the remanent polarization was 11.4 muC/cm(2), and the dielectric loss was 3.0% for 0.3-mum-thick films. From the remanent polarization and an understanding of the epitaxial geometry, a lower bound of 22.8 muC/cm(2) was determined for the spontaneous polarization of SrBi2Nb2O9. (C) 2000 American Institute of Physics. [S0003-6951(00)03844-4]. C1 Penn State Univ, Dept Mat Sci & Engn, University Pk, PA 16803 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Lettieri, J (reprint author), Penn State Univ, Dept Mat Sci & Engn, University Pk, PA 16803 USA. RI Streiffer, Stephen/A-1756-2009; Zurbuchen, Mark/H-1664-2012; Schlom, Darrell/J-2412-2013 OI Zurbuchen, Mark/0000-0002-8947-6309; Schlom, Darrell/0000-0003-2493-6113 NR 26 TC 26 Z9 26 U1 0 U2 6 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD NOV 6 PY 2000 VL 77 IS 19 BP 3090 EP 3092 DI 10.1063/1.1322055 PG 3 WC Physics, Applied SC Physics GA 369MG UT WOS:000165069500050 ER PT J AU Thompson, RK Hilsenbeck, SJ Paskach, TJ McCarley, RE Schrader, GL AF Thompson, RK Hilsenbeck, SJ Paskach, TJ McCarley, RE Schrader, GL TI Pretreatment of new reduced ternary molybdenum sulfide catalysts SO JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL LA English DT Article DE metal sulfide clusters; hydrodesulfurization; amorphous ternary molybdenum sulfides; H-2 pretreatment; chevrel phases ID CHEVREL PHASES; HYDRODESULFURIZATION; PRECURSORS AB Pretreatment of a new lanthanum molybdenum sulfide (LaMoS) hydrodesulfurization (HSD) catalyst in flowing H-2 has been investigated. Following pretreatment up to 800 degrees C, the catalyst surface area decreased from 175 to 11 m(2)/g; the average pore diameter increased due to the loss of pore diameters smaller than 100 Angstrom. TPD characterization of the as-prepared LaMoS was used to monitor the evolution of solvents and adsorbed materials up to 800 degrees C. The Mo oxidation state was examined after various pretreatment procedures using X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction (TPR). Following temperature-programmed desorption (TPD), two types of surface oxygen were detected which could be reduced at 250 degrees C and 950 degrees C by a flow of 10% H-2 in N-2. Transformation of the amorphous LaMoS to the corresponding crystalline Chevrel phase [La(Mo6S8)] was detected at 1000 degrees C using TPR and x-ray diffraction (XRD). (C) 2000 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ, Coll Engn, Dept Chem Engn, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, USDOE, Ames Lab, Ames, IA 50011 USA. RP Schrader, GL (reprint author), Iowa State Univ, Coll Engn, Dept Chem Engn, Ames, IA 50011 USA. NR 10 TC 8 Z9 8 U1 0 U2 5 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 NOV 6 PY 2000 VL 161 IS 1-2 BP 75 EP 87 DI 10.1016/S1381-1169(00)00143-6 PG 13 WC Chemistry, Physical SC Chemistry GA 364ZD UT WOS:000089923200010 ER PT J AU Gaillard, MK Nelson, B AF Gaillard, MK Nelson, B TI Quantum-induced soft supersymmetry breaking in supergravity SO NUCLEAR PHYSICS B LA English DT Article ID PAULI-VILLARS REGULARIZATION; YANG-MILLS MATTER; ONE-LOOP; COUPLINGS; MODELS AB We calculate the one-loop quantum contributions to soft supersymmetry breaking terms in the scalar potential in supergravity theories regulated a la Pauli-Villars. We find "universal" contributions, independent of the regulator masses and tree level soft supersymmetry breaking, that contribute gaugino masses and A-terms equal to the "anomaly mediated" contributions found in analyses using spurion techniques, as well as a scalar mass term not identified in those analyses. The universal terms are in general modified - and in some cases canceled - by model-dependent terms. Under certain restrictions on the couplings we recover the one-loop results of previous "anomaly mediated" supersymmetry breaking scenarios. We emphasize the model dependence of loop-induced soft terms in the potential, which are much more sensitive to the details of Planck scale physics than are the one-loop contributions to gaugino masses. We discuss the relation of our results to previous analyses. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Dept Phys, 50A-5101, Berkeley, CA 94720 USA. EM mkgaillard@lbl.gov NR 30 TC 41 Z9 41 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 NOV 6 PY 2000 VL 588 IS 1-2 BP 197 EP 212 DI 10.1016/S0550-3213(00)00494-6 PG 16 WC Physics, Particles & Fields SC Physics GA 365PU UT WOS:000089960300009 ER PT J AU Aschieri, P Brace, D Morariu, B Zumino, B AF Aschieri, P Brace, D Morariu, B Zumino, B TI Proof of a symmetrized trace conjecture for the Abelian Born-Infeld Lagrangian SO NUCLEAR PHYSICS B LA English DT Article DE duality; Born-Infeld; unilateral matrix equations AB In this paper we prove a conjecture regarding the form of the Born-Infeld Lagrangian with a U(1)(2n) gauge group after the elimination of the auxiliary fields. We show that the Lagrangian can be written as a symmetrized trace of Lorentz invariant bilinears in the field strength. More generally, we prove a theorem regarding certain solutions of unilateral matrix equations of arbitrary order. For solutions which have perturbative expansions in the matrix coefficients, the solution and all its positive powers are sums of terms which are symmetrized in all the matrix coefficients and of terms which are commutators. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RP Morariu, B (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Aschieri, Paolo/J-2965-2012 NR 6 TC 11 Z9 11 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD NOV 6 PY 2000 VL 588 IS 1-2 BP 521 EP 527 DI 10.1016/S0550-3213(00)00500-9 PG 7 WC Physics, Particles & Fields SC Physics GA 365PU UT WOS:000089960300025 ER PT J AU Fukuda, S Fukuda, Y Ishitsuka, M Itow, Y Kajita, T Kameda, J Kaneyuki, K Kobayashi, K Koshio, Y Miura, M Moriyama, S Nakahata, M Nakayama, S Obayashi, Y Okada, A Okumura, K Sakurai, N Shiozawa, M Suzuki, Y Takeuchi, H Takeuchi, Y Toshito, T 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 Kropp, WR Mine, S Price, LR Smy, M Sobel, HW Vagins, MR Ganezer, KS Keig, WE Ellsworth, RW Tasaka, S Kibayashi, A Learned, JG Matsuno, S Takemori, D Hayato, Y Ishii, T Kobayashi, T Nakamura, K Oyama, Y Sakai, A Sakuda, M Sasaki, O Kohama, M Suzuki, AT Inagaki, T Nishikawa, K Haines, TJ Blaufuss, E Kim, BK Sanford, R Svoboda, R Chen, ML Goodman, JA Guillian, G Sullivan, GW Hill, J Jung, CK Martens, K Malek, M Mauger, C McGrew, C Sharkey, E Viren, B Yanagisawa, C Kirisawa, M Inaba, S Mitsuda, C Miyano, K Okazawa, H Saji, C Takahashi, M Takahata, M Nagashima, Y Nitta, K Takita, M Yoshida, M Kim, SB Ishizuka, T Etoh, M Gando, Y Hasegawa, T Inoue, K Ishihara, K Maruyama, T Shirai, J Suzuki, A Koshiba, M Hatakeyama, Y Ichikawa, Y Koike, M Nishijima, K Fujiyasu, H Ishino, H Morii, W Watanabe, Y Golebiewska, U Kielczewska, D Boyd, SC Stachyra, AL Wilkes, RJ Young, KK AF Fukuda, S Fukuda, Y Ishitsuka, M Itow, Y Kajita, T Kameda, J Kaneyuki, K Kobayashi, K Koshio, Y Miura, M Moriyama, S Nakahata, M Nakayama, S Obayashi, Y Okada, A Okumura, K Sakurai, N Shiozawa, M Suzuki, Y Takeuchi, H Takeuchi, Y Toshito, T 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 Kropp, WR Mine, S Price, LR Smy, M Sobel, HW Vagins, MR Ganezer, KS Keig, WE Ellsworth, RW Tasaka, S Kibayashi, A Learned, JG Matsuno, S Takemori, D Hayato, Y Ishii, T Kobayashi, T Nakamura, K Oyama, Y Sakai, A Sakuda, M Sasaki, O Kohama, M Suzuki, AT Inagaki, T Nishikawa, K Haines, TJ Blaufuss, E Kim, BK Sanford, R Svoboda, R Chen, ML Goodman, JA Guillian, G Sullivan, GW Hill, J Jung, CK Martens, K Malek, M Mauger, C McGrew, C Sharkey, E Viren, B Yanagisawa, C Kirisawa, M Inaba, S Mitsuda, C Miyano, K Okazawa, H Saji, C Takahashi, M Takahata, M Nagashima, Y Nitta, K Takita, M Yoshida, M Kim, SB Ishizuka, T Etoh, M Gando, Y Hasegawa, T Inoue, K Ishihara, K Maruyama, T Shirai, J Suzuki, A Koshiba, M Hatakeyama, Y Ichikawa, Y Koike, M Nishijima, K Fujiyasu, H Ishino, H Morii, W Watanabe, Y Golebiewska, U Kielczewska, D Boyd, SC Stachyra, AL Wilkes, RJ Young, KK CA Super-Kamiokande Collaboration TI Tau neutrinos favored over sterile neutrinos in atmospheric muon neutrino oscillations SO PHYSICAL REVIEW LETTERS LA English DT Article ID SUPER-KAMIOKANDE; MATTER; FLUX; SPECTROSCOPY; RESONANCE AB The previously published atmospheric neutrino data did not distinguish whether muon neutrinos were oscillating into tau neutrinos or sterile neutrinos, as both hypotheses fit the data. Using data recorded in 1100 live days of the Super-Kamiokande detector, we use three complementary data samples to study the difference in zenith angle distribution due to neutral currents and matter effects. We find no evidence favoring sterile neutrinos, and reject the hypothesis at the 99% confidence level. On the other hand, we find that oscillation between muon and tan neutrinos suffices to explain all the results in hand. C1 Univ Tokyo, Inst Cosm Ray Res, Kashiwa, Chiba 2778582, 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. KEK, Inst Particle & Nucl Studies, High Energy Accelerator Res Org, Tsukuba, Ibaraki 3050801, Japan. Kobe Univ, Dept Phys, Kobe, Hyogo 6578501, Japan. Kyoto Univ, Dept Phys, Kyoto 6068502, Japan. Los Alamos Natl Lab, Div 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, Toyonaka, Osaka 5600043, Japan. Seoul Natl Univ, Dept Phys, Seoul 151742, South Korea. Shizuoka Univ, Dept Syst Engn, Hamamatsu, Shizuoka 4328561, Japan. Tohoku Univ, Res Ctr Neutrino Sci, Sendai, Miyagi 9808578, Japan. Univ Tokyo, Tokyo 1130033, Japan. Tokai Univ, Dept Phys, Hiratsuka, 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 Habig, A (reprint author), Univ Tokyo, Inst Cosm Ray Res, Kashiwa, Chiba 2778582, Japan. RI Obayashi, Yoshihisa/A-4472-2011; Takeuchi, Yasuo/A-4310-2011; 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; Kibayashi, Atsuko/K-7327-2015 OI Sakurai, Nobuyuki/0000-0002-1002-217X; Ishino, Hirokazu/0000-0002-8623-4080; Koshio, Yusuke/0000-0003-0437-8505; NR 25 TC 693 Z9 702 U1 5 U2 44 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 NOV 6 PY 2000 VL 85 IS 19 BP 3999 EP 4003 DI 10.1103/PhysRevLett.85.3999 PG 5 WC Physics, Multidisciplinary SC Physics GA 370HX UT WOS:000165118400004 PM 11056609 ER PT J AU Kafesaki, M Sigalas, MM Garcia, N AF Kafesaki, M Sigalas, MM Garcia, N TI Frequency modulation in the transmittivity of wave guides elastic-wave band-gap materials SO PHYSICAL REVIEW LETTERS LA English DT Article ID COMPOSITES; STATES; SYSTEMS; MEDIA AB It is shown, for the first time, that the transmittivity of wave guides created as rectilinear defects in periodic elastic band-gap materials oscillates as a function of frequency. The results are obtained using the finite difference time domain method for elastic waves propagating in two-dimensional inhomogeneous media. The oscillations of the transmittivity are due to the richness of modes in the elastic systems and, mainly, due to the periodicity of the potential in the direction of the wave propagation. Results are presented for a periodic array of Ph and Ag cylinders inserted in an epoxy host, as well as for Hg cylinders in an Al host. C1 CSIC, Lab Fis Sistemas Pequenos & Nanotecnol, E-28006 Madrid, Spain. Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. RP Kafesaki, M (reprint author), CSIC, Lab Fis Sistemas Pequenos & Nanotecnol, Serrano 144, E-28006 Madrid, Spain. RI Kafesaki, Maria/E-6843-2012 OI Kafesaki, Maria/0000-0002-9524-2576 NR 20 TC 168 Z9 177 U1 1 U2 21 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 NOV 6 PY 2000 VL 85 IS 19 BP 4044 EP 4047 DI 10.1103/PhysRevLett.85.4044 PG 4 WC Physics, Multidisciplinary SC Physics GA 370HX UT WOS:000165118400015 PM 11056620 ER PT J AU Wang, CZ Ho, KM Shirk, MD Molian, PA AF Wang, CZ Ho, KM Shirk, MD Molian, PA TI Laser-induced graphitization on a diamond (111) surface SO PHYSICAL REVIEW LETTERS LA English DT Article ID GRAPHITE; TRANSITIONS; SI; TRANSFORMATION; DYNAMICS; DISORDER; SILICON; MODEL; GAAS AB We report an atomistic simulation study of laser-induced graphitization on the diamond (111) surface. Our simulation results show that the diamond to graphite transition occurs along different pathways depending on the length of the laser pulse being used. Under nanosecond or longer laser pulses, graphitization propagates vertically into bulk layers, leading to the formation of diamond-graphite interfaces after the laser treatment. By contrast, with femtosecond (0.2-0.5 ps) laser pulses, graphitization of the surface occurs layer by layer, resulting in a clean diamond surface after the ablation. This atomistic picture provides an explanation of recent experimental observations. C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Mech Engn, Ames, IA 50011 USA. RP Wang, CZ (reprint author), Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. NR 22 TC 67 Z9 68 U1 3 U2 27 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 NOV 6 PY 2000 VL 85 IS 19 BP 4092 EP 4095 DI 10.1103/PhysRevLett.85.4092 PG 4 WC Physics, Multidisciplinary SC Physics GA 370HX UT WOS:000165118400027 PM 11056632 ER PT J AU Berger, A Inomata, A Jiang, JS Pearson, JE Bader, SD AF Berger, A Inomata, A Jiang, JS Pearson, JE Bader, SD TI Experimental observation of disorder-driven hysteresis-loop criticality SO PHYSICAL REVIEW LETTERS LA English DT Article ID SELF-ORGANIZED CRITICALITY; FERROMAGNETIC DOMAIN-WALL; BARKHAUSEN NOISE; AVALANCHES; DIMENSIONS; DYNAMICS; BEHAVIOR; MODEL AB We have studied the effect of magnetic disorder on the magnetization reversal process in thin Co/CoO films. The antiferromagnetic CoO layer allows a reversible tuning of the magnetic disorder by simple temperature variation. For temperatures above a critical temperature: T-c, we observe a discontinuous magnetization reversal, whereas smooth magnetization loops occur for T < T-c. Our measurements establish the existence of a disorder-driven critical point in the nonequilibrium phase diagram. In addition, we observe scaling behavior in the vicinity of the critical point and determine the critical exponents = 0.022 +/- 0.006 and beta delta = 0.30 +/- 0.03 for this two-dimensional system. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Fujitsu File Memory Lab, Atsugi, Kanagawa, Japan. RP Berger, A (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Bader, Samuel/A-2995-2013; Berger, Andreas/D-3706-2015 OI Berger, Andreas/0000-0001-5865-6609 NR 26 TC 63 Z9 63 U1 3 U2 10 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD NOV 6 PY 2000 VL 85 IS 19 BP 4176 EP 4179 DI 10.1103/PhysRevLett.85.4176 PG 4 WC Physics, Multidisciplinary SC Physics GA 370HX UT WOS:000165118400048 PM 11056653 ER PT J AU Gschneidner, KA Pecharsky, VK Bruck, E Duijn, HGM Levin, EM AF Gschneidner, KA Pecharsky, VK Bruck, E Duijn, HGM Levin, EM TI Comment on "Direct measurement of the 'giant' adiabatic temperature change in Gd5Si2Ge2" SO PHYSICAL REVIEW LETTERS LA English DT Article C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Mat Sci & Engn, Ames, IA 50011 USA. Univ Amsterdam, Van der Waals Zeerman Inst, Amsterdam, Netherlands. RP Gschneidner, KA (reprint author), Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. RI Bruck, Ekkes/E-3365-2014 NR 4 TC 94 Z9 97 U1 0 U2 19 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 NOV 6 PY 2000 VL 85 IS 19 BP 4190 EP 4190 DI 10.1103/PhysRevLett.85.4190 PG 1 WC Physics, Multidisciplinary SC Physics GA 370HX UT WOS:000165118400053 PM 11056658 ER PT J AU Wong, KL Itoh, K Itoh, SI Fukuyama, A Yagi, M AF Wong, KL Itoh, K Itoh, SI Fukuyama, A Yagi, M TI Short wavelength fluctuations and electron transport in TFTR SO PHYSICS LETTERS A LA English DT Article ID REVERSED MAGNETIC SHEAR AB Correlation between electron heat diffusivity and short wavelength (k rho (i) similar to 5) fluctuation amplitude was observed in the TFTR tokamak in the cure of ERS plasmas (Phys. Lett. A 236 (1997) 339). These fluctuations propagate in the ion diamagnetic drift direction with wave number comparable to omega (pe)/c Further analysis of these data yields the ratios chi (e)/chi (i) and chi (e)/D-e, and their values are consistent with the picture that the electron transport is mainly induced by the short wavelength fluctuations in the plasma core where the long wavelength (k rho (i) similar to 1) fluctuations are absent. Although there is not enough information to identify these short wavelength modes, the values of chi (e) is found to be comparable to theoretical predictions based on the current diffusive ballooning mode theory (Plasma Phys. Control. Fusion 36 (1994) 279). (C) 2000 Elsevier Science B.V. All rights reserved. C1 Princeton Univ, Plasma Phys Lab, Princeton, NJ 08543 USA. Natl Inst Fus Sci, Gifu, Japan. Kyushu Univ, Fukuoka, Kyushu, Japan. Kyoto Univ, Kyoto, Japan. RP Wong, KL (reprint author), Princeton Univ, Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. RI Kyushu, RIAM/F-4018-2015; U-ID, Kyushu/C-5291-2016 NR 10 TC 9 Z9 9 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 NOV 6 PY 2000 VL 276 IS 5-6 BP 281 EP 285 DI 10.1016/S0375-9601(00)00669-1 PG 5 WC Physics, Multidisciplinary SC Physics GA 378YN UT WOS:000165613500012 ER PT J AU Osman, H Schmidt, J Svensson, K Palmer, RE Shigeta, Y Wilcoxon, JP AF Osman, H Schmidt, J Svensson, K Palmer, RE Shigeta, Y Wilcoxon, JP TI STM studies of passivated Au nanocrystals immobilised on a passivated Au(111) surface: ordered arrays and single electron tunnelling SO CHEMICAL PHYSICS LETTERS LA English DT Article ID SCANNING-TUNNELING-MICROSCOPY; ASSEMBLED MOLECULAR NANOSTRUCTURE; ALKANETHIOL MONOLAYERS; ROOM-TEMPERATURE; GOLD CLUSTERS; COULOMB STAIRCASE; GRAPHITE AB We have employed scanning tunnelling microscopy (STM) in ultra-high vacuum (UHV) to explore the assembly and electron transport properties of an ordered layer of passivated gold clusters adsorbed onto an alkanethiol passivated Au(111) surface. The passivation of the Au(111) surface stabilises the cluster layer. STM images show ordered hexagonal arrays of the nanoparticles extending over distances >100 nm with a mean nearest neighbour spacing of 6.5 nm. I-V measurements show a strong non-linear I-V relationship, as well as equidistant steps of width similar to0.15 V above a bias voltage of similar to2 V, attributed to a Coulomb staircase, i.e., single electron charging, in this structure. (C) 2000 Elsevier Science B.V, All rights reserved. C1 Univ Birmingham, Sch Phys & Astron, Nanoscale Phys Res Lab, Birmingham B15 2TT, W Midlands, England. Yokohama City Univ, Fac Sci, Kanazawa Ku, Yokohama, Kanagawa 236, Japan. Sandia Natl Labs, Nanostruct & Adv Mat Dept 1152, Albuquerque, NM 87185 USA. RP Univ Birmingham, Sch Phys & Astron, Nanoscale Phys Res Lab, Birmingham B15 2TT, W Midlands, England. EM r.e.palmer@bham.ac.uk RI Palmer, Richard/A-5366-2008; Svensson, Krister/C-5469-2012 OI Palmer, Richard/0000-0001-8728-8083; Svensson, Krister/0000-0003-1711-5595 NR 27 TC 24 Z9 24 U1 1 U2 5 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 NOV 3 PY 2000 VL 330 IS 1-2 BP 1 EP 6 DI 10.1016/S0009-2614(00)01072-1 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 372TA UT WOS:000165249100001 ER PT J AU Chen, LH McBranch, D Wang, R Whitten, D AF Chen, LH McBranch, D Wang, R Whitten, D TI Surfactant-induced modification of quenching of conjugated polymer fluorescence by electron acceptors: applications for chemical sensing SO CHEMICAL PHYSICS LETTERS LA English DT Article ID PHOTOCHEMICAL REACTIVITY; ORGANIZED ASSEMBLIES; COMPLEX-FORMATION; MICELLES; VESICLES; SOLVENTS; STILBENE; PROBE AB Both the photophysics and the fluorescence quenching behavior of an anionic conjugated polymer towards various small molecule quenchers can be modulated effectively by complexing the polymer with a simple countercharged detergent. For example upon adding odecyltrimethylammonium bromide (DTA) to the polymer, cationic quenchers such as methyl viologen become less effective while the quenching by neutral reagents - most notably nitroaromatics or cyanoaromatics - is enhanced. Thus, the polymer-detergent complex provides a new platform for sensing chemical agents via fluorescence quenching. Thin films formed from the complex exhibit high sensitivity to quenching by nitroaromatic vapor and reasonable reversibility. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Biosci Div, Los Alamos, NM 87545 USA. LLC, QLT Biosyst, Santa Fe, NM 87501 USA. RP Chen, LH (reprint author), Univ Calif Los Alamos Natl Lab, Biosci Div, POB 1663, Los Alamos, NM 87545 USA. NR 14 TC 111 Z9 113 U1 3 U2 19 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 NOV 3 PY 2000 VL 330 IS 1-2 BP 27 EP 33 DI 10.1016/S0009-2614(00)00970-2 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 372TA UT WOS:000165249100005 ER PT J AU Liu, K Cho, HS Hoyt, DW Nguyen, TN Olds, P Kelly, JW Wemmer, DE AF Liu, K Cho, HS Hoyt, DW Nguyen, TN Olds, P Kelly, JW Wemmer, DE TI Deuterium-proton exchange on the native wild-type transthyretin tetramer identifies the stable core of the individual subunits and indicates mobility at the subunit interface SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE transthyretin; amyloid; hydrogen exchange; NMR spectroscopy; protection factor ID PROTEIN SECONDARY STRUCTURE; AMYLOID FIBRIL FORMATION; GROUP HYDROGEN-EXCHANGE; CRYSTAL-STRUCTURE; CHEMICAL-SHIFT; IN-VITRO; VARIANT; C-13; DENATURATION; MUTATIONS AB Transthyretin is a human protein capable of amyloid formation that is believed to cause several types of amyloid disease, depending on the sequence deposited. Previous studies have demonstrated that wild-type transthyretin (TTR), although quite stable, forms amyloid upon dissociation from its native tetrameric form into monomers with an altered conformation. Many naturally occurring single-site variants of TTR display decreased stability in vitro, manifested by the early onset familial amyloid diseases in vivo. Only subtle structural changes were observed in X-ray crystallographic structures of these disease associated variants. In this study, the stability of the wild-type TTR tetramer was investigated at the residue-resolution level by monitoring H-2-H exchange via NMR spectroscopy. The measured protection factors for slowly-exchanging amide hydrogen atoms reveal a stable core consisting of strands A, B, E, F, and interestingly, the loop between strands A and B. Ln addition, the faster exchange of amide groups from residues at the subunit interfaces suggests unexpected mobility in these regions. This information is crucial for future comparisons between disease-associated and wild-type tetramers. Such studies can directly address the regions of TTR that become destabilized as a consequence of single amino acid substitutions, providing clues to aspects of TTR amyloidogenesis. (C) 2000 Academic Press. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Phys Biosci Div, Berkeley, CA 94720 USA. Pacific NW Natl Lab, Richland, WA 99352 USA. Scripps Res Inst, Dept Chem, La Jolla, CA 92037 USA. Scripps Res Inst, Skaggs Inst Chem Biol, La Jolla, CA 92037 USA. RP Wemmer, DE (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Dept Chem, MC-1460, Berkeley, CA 94720 USA. RI Hoyt, David/H-6295-2013 FU NIA NIH HHS [AG10770]; NIDDK NIH HHS [DK46335] NR 32 TC 47 Z9 47 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 NOV 3 PY 2000 VL 303 IS 4 BP 555 EP 565 DI 10.1006/jmbi.2000.4164 PG 11 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 373CM UT WOS:000165270900010 PM 11054291 ER PT J AU Michael, JV Kumaran, SS Su, MC AF Michael, JV Kumaran, SS Su, MC TI Reply to comment on "Rate constants for CH3+O-2 -> CH3O+Oat high temperature and evidence for H2CO+O-2 -> HCO+HO2" SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID SHOCK TUBE TECHNIQUE; THERMAL-DECOMPOSITION; CHEMICAL-KINETICS; ATOM ABSORPTION; PHOTOLYSIS; FLASH; OXIDATION; SYSTEM; RANGE; GAS C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Michael, JV (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Michael, Joe/E-3907-2010 NR 37 TC 3 Z9 3 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 NOV 2 PY 2000 VL 104 IS 43 BP 9800 EP 9802 DI 10.1021/jp994495u PG 3 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 371UN UT WOS:000165197800020 ER PT J AU Rice, MJ Chakraborty, AK Bell, AT AF Rice, MJ Chakraborty, AK Bell, AT TI Theoretical studies of the coordination and stability of divalent cations in ZSM-5 SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID SELECTIVE CATALYTIC REDUCTION; EFFECTIVE CORE POTENTIALS; CU-EXCHANGED ZEOLITES; LEAN NOX REDUCTION; NITRIC-OXIDE; CU-ZSM-5 CATALYSTS; MOLECULAR CALCULATIONS; NITROGEN MONOXIDE; ACTIVE-SITES; DECOMPOSITION AB The coordination of divalent metal cations to ZSM-5 has been investigated using gradient-corrected density functional theory (DFT). Coordination at both isolated charge-exchange sites and pairs of charge-exchange sites was considered for Co2+, Cu2+, Fe2+, Ni2+, Pd2+, Pt2+, Ru2+, Rh2+, and Zn2+. Thermodynamic calculations of the stability of M2+ to reduction to MO and demetalation to form MO, particles were also carried out. The results indicate that Cu2+, Co2+, Fe2+, and Ni2+ are coordinated preferentially to five-membered rings containing two Al atoms, which are located on the walls of the sinusoidal channels, whereas Pd2+, Pt-2+, Ru2+, Rh2+, and Zn2+ are coordinated preferentially to six-membered rings located on the walls of the sinusoidal channels. Examination of the stability of dimer cations of the form [M-O-M](2+) shows that such structures are not generally stable to hydrolysis, with the possible exception of [Cu-O-Cu](2+). The findings of these calculations are in good general agreement with experimental results. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Chem Engn, Div Chem Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Chem Engn, Div Sci Mat, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Chem, Div Chem Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Chem, Div Mat Sci, Berkeley, CA 94720 USA. RP Bell, AT (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Chem Engn, Div Chem Sci, Berkeley, CA 94720 USA. OI Bell, Alexis/0000-0002-5738-4645 NR 56 TC 66 Z9 66 U1 4 U2 25 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 NOV 2 PY 2000 VL 104 IS 43 BP 9987 EP 9992 DI 10.1021/jp0009352 PG 6 WC Chemistry, Physical SC Chemistry GA 371UP UT WOS:000165197900008 ER PT J AU Xie, SB Chen, KD Bell, AT Iglesia, E AF Xie, SB Chen, KD Bell, AT Iglesia, E TI Structural characterization of molybdenum oxide supported on zirconia SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID X-RAY-ABSORPTION; LASER RAMAN-SPECTROSCOPY; OXIDATIVE DEHYDROGENATION; ALUMINA CATALYSTS; GAMMA-ALUMINA; METAL-OXIDES; K-EDGE; MONOLAYER; SYSTEMS; ALKANES AB X-ray diffraction and X-ray absorption and Raman spectroscopies were used to determine the structure of dispersed and crystalline structures in MoOx/ZrO2 catalysts useful in the oxidative dehydrogenation of alkanes. The MoOx surface density on ZrO2 was varied over a wide range (0.35-50 Mo/nm(2)) by changing the Mo content (1-44 wt % MoO3) and the treatment temperature (393-973 K). Raman spectra showed that MoOx/ZrO2 samples with low surface density (<5 Mo/nm(2)) treated at temperatures below 873 K initially contain isolated tetrahedral MoOx species; these species oligomerize to form two-dimensional structures with bridging Mo-O-Mo bonds as the surface density increased to values typical for a polymolybdate monolayer (5 Mo/nm(2)). An increase in surface density led to a shift in the nu>(*) over bar * (Mo=O) Raman band to higher frequencies and to changes in the near-edge X-ray absorption spectra. Both of these are consistent with the growth of these polymolybdate domains with increasing Mo surface density, as also suggested by the concurrent decrease in the UV-visible absorption energy. Thermal treatment at 973 K led to the dissociation of Mo-O-Mo bonds and to the formation of tetragonal-pyramidal O=MoO4 species. For MoOx/ZrO2 samples with Mo surface densities greater than 5 Mo/nm(2), MoO3 and Zr(MoO4)(2) were detected by Raman and for larger crystallites also by X-ray diffraction. Treatment of these samples in air at 723 K led to the predominant formation of MoO3, while higher temperatures led to a solid-state reaction between MoO3 and ZrO2 to form Zr(MoO4)(2) This structural evolution was confirmed by the evolution of pre-edge and near edge features in the X-ray absorption spectra of these high surface density samples. Zr(MoO4)(2) contains Mo6+ cations in a distorted tetrahedral coordination with one oxygen bonded only to molybdenum and the other three shared by Zr and Mo atoms. The Raman bands observed for Zr(MoO4)(2) at 750, 945, and 1003 cm(-1) were assigned to nu (sym)(O-Mo-O), nu (asym)(O-Mo-O), and nu>(*) over bar * (Mo=O) vibrational modes, respectively, based on the analysis of the Raman bands observed after O-18(2) exchange with lattice oxygen atoms. Bridging O atoms in Mo-O-Mo species exchanged with gas phase O-18(2) more readily than terminal Mo=O species. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. RP Bell, AT (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RI Song, Kunshan/C-7073-2008; Iglesia, Enrique/D-9551-2017; OI Iglesia, Enrique/0000-0003-4109-1001; Bell, Alexis/0000-0002-5738-4645 NR 62 TC 69 Z9 70 U1 0 U2 32 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 NOV 2 PY 2000 VL 104 IS 43 BP 10059 EP 10068 DI 10.1021/jp002419h PG 10 WC Chemistry, Physical SC Chemistry GA 371UP UT WOS:000165197900018 ER PT J AU Bracht, H Nicols, SP Walukiewicz, W Silveira, JP Briones, F Haller, EE AF Bracht, H Nicols, SP Walukiewicz, W Silveira, JP Briones, F Haller, EE TI Large disparity between gallium and antimony self-diffusion in gallium antimonide SO NATURE LA English DT Article ID GAAS ISOTOPE HETEROSTRUCTURES; V COMPOUND SEMICONDUCTORS; ELECTRONIC-STRUCTURE; VACANCIES; GASB AB The most fundamental mass transport process in solids is selfdiffusion. The motion of host-lattice (`self-') atoms in solids is mediated by point defects such as vacancies or interstitial atoms, whose formation and migration enthalpies determine the kinetics of this thermally activated process(1,2). Self-diffusion studies also contribute to the understanding of the diffusion of impurities, and a quantitative understanding of self- and foreign-atom diffusion in semiconductors is central to the development of advanced electronic devices. In the past few years, self- diffusion studies have been performed successfully with isotopically controlled semiconductor heterostructures of germanium(3), silicon(4), gallium arsenide(5,6) and gallium phosphide(7). Self- diffusion studies with isotopically controlled GaAs and GaP have been restricted to Ga self- diffusion, as only Ga has two stable isotopes, Ga-69 and Ga-71. Here we report self- diffusion studies with an isotopically controlled multilayer structure of crystalline GaSb. Two stable isotopes exist for both Ga and Sb, allowing the simultaneous study of diffusion on both sublattices. Our experiments show that near the melting temperature, Ga diffuses more rapidly than Sb by over three orders of magnitude. This surprisingly large difference in atomic mobility requires a physical explanation going beyond standard diffusion models. Combining our data for Ga and Sb diffusion with related results for foreign-atom diffusion in GaSb (refs 8, 9), we conclude that the unusually slow Sb diffusion in GaSb is a consequence of reactions between defects on the Ga and Sb sublattices, which suppress the defects that are required for Sb diffusion. C1 Univ Calif Berkeley, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. CSIC, Ctr Nacl Microelect, Inst Microelect Madrid, Madrid 28066, Spain. RP Bracht, H (reprint author), Univ Calif Berkeley, Berkeley, CA 94720 USA. RI Microelectronica de Madrid, Instituto de/D-5173-2013 OI Microelectronica de Madrid, Instituto de/0000-0003-4211-9045 NR 19 TC 67 Z9 68 U1 3 U2 26 PU MACMILLAN PUBLISHERS LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD NOV 2 PY 2000 VL 408 IS 6808 BP 69 EP 72 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 369DH UT WOS:000165050400051 PM 11081507 ER PT J AU Wang, Y Espenson, JH AF Wang, Y Espenson, JH TI Efficient catalytic conversion of pyridine N-oxides to pyridine with an oxorhenium(V) catalyst SO ORGANIC LETTERS LA English DT Article ID SELECTIVE DEOXYGENATION AB [GRAPHICS] The compound CH3Re(O)(SR)(2)PPh3, where (SR)(2) represents the dianion of 2-(mercaptomethyl)thiophenol, catalyzes the rapid and efficient transfer of an oxygen atom from a wide range of ring-substituted pyridine N-oxides to triphenylphosphine, yielding the pyridines in high yield. 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 14 TC 47 Z9 48 U1 1 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1523-7060 J9 ORG LETT JI Org. Lett. PD NOV 2 PY 2000 VL 2 IS 22 BP 3525 EP 3526 DI 10.1021/ol006595k PG 2 WC Chemistry, Organic SC Chemistry GA 370EQ UT WOS:000165110900030 ER PT J AU Ideguchi, E Cederwall, B Wyss, R Back, T Lagergren, K Johnson, A Klamra, W Cederkall, J Devlin, M Elson, J LaFosse, DR Lerma, F Sarantites, DG Tomov, V Hausmann, M Jungclaus, A Napoli, DR Carpenter, MP Janssens, RVF Kondev, FG Lauritsen, T Lister, CJ Seweryniak, D Wiedenhoever, I Clark, RM Fallon, P Lee, IY Macchiavelli, AO Macleod, RW AF Ideguchi, E Cederwall, B Wyss, R Back, T Lagergren, K Johnson, A Klamra, W Cederkall, J Devlin, M Elson, J LaFosse, DR Lerma, F Sarantites, DG Tomov, V Hausmann, M Jungclaus, A Napoli, DR Carpenter, MP Janssens, RVF Kondev, FG Lauritsen, T Lister, CJ Seweryniak, D Wiedenhoever, I Clark, RM Fallon, P Lee, IY Macchiavelli, AO Macleod, RW TI Superdeformation in Tc-91 SO PHYSICS LETTERS B LA English DT Article ID QUADRUPOLE-MOMENTS; MASS REGION; STATES; NUCLEI; BANDS; TRANSITIONS AB A high-spin rotational band with 11 gamma -ray transitions has barn observed in Tc-91. The dynamical moment of inertia as well as the transition quadrupole moment of 8.1(-1.4)(+1.9) eb measured for this band show the characteristics of a superdeformed band. However, the shape is more elongated than in the neighbouring A = 80-90 superdeformed nuclei. Theoretical interpretations of the band within the cranked Strutinsky approach based on two different Woods-Saxon potential parameterisations are presented. Even though an unambiguous configuration assignment proved difficult, both calculations indicate a larger deformation and at least three additional high-N intruder orbitals occupied compared to the lighter SD nuclei. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Royal Inst Technol, Dept Phys, S-10405 Stockholm, Sweden. Washington Univ, Dept Chem, St Louis, MO 63130 USA. Univ Gottingen, Inst Phys 2, D-3400 Gottingen, Germany. Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Ideguchi, E (reprint author), Royal Inst Technol, Dept Phys, Frescativagen 24, S-10405 Stockholm, Sweden. RI Devlin, Matthew/B-5089-2013; Cederwall, Bo/M-3337-2014; Carpenter, Michael/E-4287-2015; Napoli, Daniel R./D-9863-2012; OI Devlin, Matthew/0000-0002-6948-2154; Cederwall, Bo/0000-0003-1771-2656; Carpenter, Michael/0000-0002-3237-5734; Napoli, Daniel R./0000-0002-8154-6958; Back, Torbjorn/0000-0003-1996-0805 NR 32 TC 5 Z9 5 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 NOV 2 PY 2000 VL 492 IS 3-4 BP 245 EP 253 DI 10.1016/S0370-2693(00)01114-X PG 9 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 373XQ UT WOS:000165315700003 ER PT J AU Edwards, BC AF Edwards, BC TI Design and deployment of a space elevator SO ACTA ASTRONAUTICA LA English DT Article ID CARBON NANOTUBES; POWER AB The space elevator was first proposed in the 1960s as a method of getting into space. The initial studies of a space elevator outlined the basic concept of a cable strung between Earth and space but concluded that no material available at the time had the required properties to feasibly construct such a cable. With the discovery of carbon nanotubes in 1991 it is now possible to realistically discuss the construction of a space elevator. Although currently produced only in small quantities, carbon nanotubes appear to have the strength-to-mass ratio required for this endeavor. However, fabrication of the cable required is only one of the challenges in construction of a space elevator. Powering the climbers, surviving micrometeor impacts, lightning strikes and low-Earth-orbit debris collisions are some of the problems that are now as important to consider as the production of the carbon nanotube cable. We consider various aspects of a space elevator and find each of the problems that this endeavor will encounter can be solved with current or near-future technology. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87544 USA. RP Edwards, BC (reprint author), Univ Calif Los Alamos Natl Lab, Mail Stop D436, Los Alamos, NM 87544 USA. RI Chang, Yanwei/D-8117-2013 NR 32 TC 59 Z9 60 U1 8 U2 53 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD NOV PY 2000 VL 47 IS 10 BP 735 EP 744 DI 10.1016/S0094-5765(00)00111-9 PG 10 WC Engineering, Aerospace SC Engineering GA 390YJ UT WOS:000166327100001 ER PT J AU Miao, J Sayre, D AF Miao, J Sayre, D TI On possible extensions of X-ray crystallography through diffraction-pattern oversampling SO ACTA CRYSTALLOGRAPHICA SECTION A LA English DT Article ID PHASE RETRIEVAL; TRANSMISSION; IMAGES AB It is known that sampling the diffraction pattern of a finite specimen, at a spacing somewhat finer than the Nyquist spacing (the inverse of the size of the diffracting specimen), corresponds to generating a no-density region surrounding the electron density of the specimen. This no-density region can then be used to retrieve the phase information. In earlier papers [Miao, Sayre & Chapman (1998). J. Opt. Soc. Am. A15, 1662-1669; Sayre, Chapman & Miao (1998). Acta Cryst. A54, 232-239], it was demonstrated, in the case of noncrystalline specimens, that this no-density region could be used to retrieve the phase information; here the same is performed for crystalline and near-crystalline specimens. By employment of an iterative algorithm, the phase information could be recovered from computer-generated oversampled diffraction patterns of small specimens that are (a) perfect or imperfect crystals, or (b) have a repeated motif without orientational regularity, or (c) are an unrepeated motif, such as an amorphous glass, a single molecule or a single biological cell. Cases (a) and (b) represent an extension over work recently published [Miao, Charalambous, Kirz & Sayre (1999). Nature (London), 400, 342-344]. Our algorithm requires an approximate envelope for the specimen. It does not require any structural knowledge concerning the specimen and does not require data to atomic resolution (although it can use such data if present). After a few hundred to a few thousand iterations, the correct phase set and image are recovered. The oversampling technique thus greatly extends the specimen range of X-ray crystallography but it imposes a high radiation dose on the specimens compared with the situation in crystallography, in which it is usual for the pattern to be sampled at the (much less fine) Bragg spacing (the inverse of the size of the unit cell). In cases where the specimen is a crystal, there are also possibilities for oversampling relative to Bragg (instead of Nyquist) sampling, thus providing a lesser degree of oversampling and the possibility of lower dosage. Damage of the specimen in consequence of the dose will in many cases seriously affect the quality and resolution of the imaging, but in at least one case [the biological cell in (c) above] the imaging obtainable with the aid of a cryogenic protective technique should surpass any other present method of whole-cell imaging. In addition, with the possible appearance in the future of free electron lasers (>10(12) photons and <200 fs per pulse), it is possible to circumvent the radiation-damage problem by recording diffraction patterns before damage manifests itself. C1 SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. RP Miao, J (reprint author), Stanford Synchrotron Radiat Lab, POB 20450 MS 69, Stanford, CA 94309 USA. NR 26 TC 66 Z9 66 U1 1 U2 12 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0108-7673 J9 ACTA CRYSTALLOGR A JI Acta Crystallogr. Sect. A PD NOV PY 2000 VL 56 BP 596 EP 605 DI 10.1107/S010876730001031X PN 6 PG 10 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 368EU UT WOS:000090105400013 ER PT J AU Schultz, AJ Figgis, BN Sobolev, AN AF Schultz, AJ Figgis, BN Sobolev, AN TI Na2Fe(CN)(5)(NO)center dot 2D(2)O at 11 and 293 K by X-ray, and at 15 K by neutron diffraction SO ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS LA English DT Article ID SODIUM-NITROPRUSSIDE; ELECTRON-DENSITY; CRYSTALLOGRAPHY; CRYSTALS; STATE AB The crystal structure of Na2Fe(CN)(5)(NO). 2D(2)O, disodium pentacyanonitrosylferrate(III) bis(dideuterium oxide), has been determined by X-ray diffraction at 11 and 293 K, and by neutron diffraction at 15 K. The accurate and extensive data sets lead to more precise determinations than are available from earlier work. The agreement in atomic positional and displacement parameters between the determinations at low temperature is very good. C1 Univ Western Australia, Dept Chem, Nedlands, WA 6907, Australia. Argonne Natl Lab, Intense Pulsed Neutron Source, Argonne, IL 60439 USA. RP Figgis, BN (reprint author), Univ Western Australia, Dept Chem, Nedlands, WA 6907, Australia. NR 22 TC 3 Z9 3 U1 0 U2 2 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 NOV PY 2000 VL 56 BP 1289 EP 1291 DI 10.1107/S0108270100008763 PN 11 PG 3 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 375EL UT WOS:000165386500001 PM 11077270 ER PT J AU Kuhn, P Deacon, AM Comoso, S Rajaseger, G Kini, RM Uson, I Kolatkar, PR AF Kuhn, P Deacon, AM Comoso, S Rajaseger, G Kini, RM Uson, I Kolatkar, PR TI The atomic resolution structure of bucandin, a novel toxin isolated from the Malayan krait, determined by direct methods SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article ID REFINED CRYSTAL-STRUCTURE; ANIMAL TOXINS; IMPLEMENTATION; BUNGAROTOXIN; ERABUTOXIN; RESIDUES; DESIGN; MODEL; VENOM AB Bucandin is a novel presynaptic neurotoxin isolated from Bungarus candidus (Malayan krait). It has the unique property of enhancing presynaptic acetylcholine release and represents a family of three-finger toxins with an additional disulfide in the first loop. There are no existing structures from this sub-category of three-finger toxins. The X-ray crystal structure of bucandin has been determined by the Shake-and-Bake direct-methods procedure. The resulting electron-density maps were of outstanding quality and allowed the automated tracing of 61 of the 63 amino-acid residues, including their side chains, and the placement of 48 solvent molecules. The 0.97 Angstrom resolution full-matrix least-squares refinement converged to a crystallographic R factor of 12.4% and the final model contains 118 solvent molecules. This is the highest resolution structure of any member of the three-finger toxin family and thus it can serve as the best model for other members of the family. Furthermore, the structure of this novel toxin will help in understanding its unique ability to enhance acetylcholine release. The unique structure resulting from the fifth disulfide bond residing in the first loop improves the understanding of other toxins with a similar arrangement of disulfide bonds. C1 Inst Mol & Cell Biol, Bioinformat Ctr, Singapore 117609, Singapore. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. Natl Univ Singapore, Fac Sci, Biosci Ctr, Singapore 119260, Singapore. Inst Inorgan Chem, D-37077 Gottingen, Germany. RP Kolatkar, PR (reprint author), Inst Mol & Cell Biol, Bioinformat Ctr, 30 Med Dr, Singapore 117609, Singapore. EM kolatkar@bic.nus.edu.sg RI ASTAR, IMCB/E-2320-2012; Kini, Manjunatha/H-8029-2012; OI kolatkar, prasanna/0000-0003-4970-5944 NR 38 TC 24 Z9 26 U1 0 U2 0 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0907-4449 J9 ACTA CRYSTALLOGR D JI Acta Crystallogr. Sect. D-Biol. Crystallogr. PD NOV PY 2000 VL 56 BP 1401 EP 1407 DI 10.1107/S0907444900011501 PN 11 PG 7 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 374FX UT WOS:000165336100006 PM 11053837 ER PT J AU Rice, LM Earnest, TN Brunger, AT AF Rice, LM Earnest, TN Brunger, AT TI Single-wavelength anomalous diffraction phasing revisited SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article ID CRYSTAL-STRUCTURE; MACROMOLECULAR STRUCTURES; SELENOMETHIONYL PROTEINS; ANGSTROM RESOLUTION; MAD; DOMAIN; CRYSTALLOGRAPHY; SCATTERING; LYSOZYME; PHASES AB Multiwavelength anomalous diffraction (MAD) phasing has become a routinely used tool for determining new macromolecular structures. The MAD method has stringent data-collection requirements, typically necessitating radiation-resistant crystals and access to a tunable synchrotron beamline. In cases where synchrotron time, monochromator tunability or radiation damage is a concern or where high-throughput structure determination is desired, phasing methods capable of producing interpretable electron-density maps from less data become attractive alternatives to MAD. The increasing availability of tunable synchrotron data-collection facilities prompted the authors to revisit single-wavelength anomalous diffraction (SAD) phasing used in conjunction with a phase-ambiguity resolving method such as solvent flattening. The anomalous diffraction from seven different selenomethionine-labelled protein crystals has been analysed and it is shown that in conjunction with solvent flattening, diffraction data from the peak anomalous wavelength alone can produce interpretable electron-density maps of comparable quality to those resulting from full MAD phasing. Single-wavelength anomalous diffraction (SAD) phasing can therefore be a time-efficient alternative to MAD. The data also show that radiation damage can have a significant effect on the quality of SAD/MAD diffraction data. These results may be useful in the design of optimal strategies for collection of the diffraction data. C1 Stanford Univ, Howard Hughes Med Inst, Stanford, CA 94305 USA. Stanford Univ, Dept Cellular & Mol Physiol, Stanford, CA 94305 USA. Stanford Univ, Dept Neurol & Neurol Sci, Stanford, CA 94305 USA. Stanford Univ, Stanford Synchrotron Radiat Lab, Stanford, CA 94305 USA. Yale Univ, Dept Mol Biophys & Biochem, New Haven, CT 06520 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source, Macromol Crystallog Facil, Berkeley, CA 94720 USA. RP Brunger, AT (reprint author), Stanford Univ, Howard Hughes Med Inst, Stanford, CA 94305 USA. NR 39 TC 103 Z9 104 U1 0 U2 12 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 NOV PY 2000 VL 56 BP 1413 EP 1420 DI 10.1107/S0907444900010039 PN 11 PG 8 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 374FX UT WOS:000165336100008 PM 11053839 ER PT J AU Colovos, C Toth, EA Yeates, TO AF Colovos, C Toth, EA Yeates, TO TI Evaluation of phase accuracy via topological and geometrical analysis of electron-density maps SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article ID MACROMOLECULAR CRYSTALLOGRAPHY; INFORMATION AB An empirical function is developed to measure the protein-like character of electron-density maps. The function is based upon a systematic analysis of numerous local and global map properties or descriptors. Local descriptors measure the occurrence throughout the unit cell of unique patterns on various defined templates, while global descriptors enumerate topological characteristics that define the connectivity and complexity of electron-density isosurfaces. We examine how these quantitative descriptors vary as error is introduced into the phase sets used to generate maps. Informative descriptors are combined in an optimal fashion to arrive at a predictive function. When the topological and geometrical analysis is applied to protein maps generated from phase sets with varying amounts of error, the function is able to estimate changes in average phase error with an accuracy of better than 10 degrees. Additionally, when used to monitor maps generated with experimental phases from different heavy-atom models, the analysis clearly distinguishes between the correct heavy-atom substructure solution and incorrect heavy-atom solutions. The function is also evaluated as a tool to monitor changes in map quality and phase error before and after density-modification procedures. C1 Univ Calif Los Angeles, Dept Chem & Biochem, DOE MBI Lab Struct Biol & Mol Med, Los Angeles, CA 90095 USA. Harvard Univ, Sch Med, Dept Biol Chem & Mol Pharmacol, Boston, MA 02115 USA. RP Yeates, TO (reprint author), Univ Calif Los Angeles, Dept Chem & Biochem, DOE MBI Lab Struct Biol & Mol Med, Box 951570, Los Angeles, CA 90095 USA. OI Yeates, Todd/0000-0001-5709-9839 FU NIGMS NIH HHS [GM07185] NR 15 TC 5 Z9 5 U1 0 U2 2 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0907-4449 J9 ACTA CRYSTALLOGR D JI Acta Crystallogr. Sect. D-Biol. Crystallogr. PD NOV PY 2000 VL 56 BP 1421 EP 1429 DI 10.1107/S0907444900011227 PN 11 PG 9 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 374FX UT WOS:000165336100009 PM 11053840 ER PT J AU Liang, LY Korte, N Gu, BH Puls, R Reeter, C AF Liang, LY Korte, N Gu, BH Puls, R Reeter, C TI Geochemical and microbial reactions affecting the long-term performance of in situ 'iron barriers' SO ADVANCES IN ENVIRONMENTAL RESEARCH LA English DT Article DE in situ barriers; dechlorination; water treatment; geochemical reactions; microbial reactions; long-term performance; precipitation; clogging ID ZERO-VALENT IRON; REDUCTIVE DEHALOGENATION; CARBON-TETRACHLORIDE; REMEDIATION; GROUNDWATER; METALS; DEGRADATION; CORROSION; KINETICS; WATER AB The in situ application of granular iron (Fe-0) has become popular for the destruction of halogenated organic compounds and for the immobilization of specific metals in groundwater. However, a knowledge gap exists concerning the long-term performance of the Fe-0-barriers. The corrosion of Fe-0 may produce mineral precipitates that alter the system's hydraulic integrity. For example, data from existing barriers show varying trends in pH, alkalinity, mineral precipitation, and microbial activity. Although the chemical behaviors are site-specific, this paper discusses the concepts involved in developing a generic approach for predicting the trend of aqueous and surface speciation, and the resulting effects on Fe-0 treatment systems. Observations from existing Fe barriers are summarized, and the chemical and microbial processes that influence chemical speciation, both in water and on surfaces, are reviewed. A conceptual geochemical model is presented, which illustrates the factors that must be considered in developing a quantitative model that can be used to design monitoring plans for timely detection of clogging in Fe-0 reactive barriers. In order to develop quantitative predictive models, field and laboratory research should: (1) assess the extent and rates of media deterioration by analyzing coupled chemical and microbial reactions; and (2) identify the controlling mechanisms for hydraulic alteration within and around Fe-0 barriers. (C) 2000 Published by Elsevier Science Ltd. All rights reserved. C1 Oak Ridge Natl Lab, Grand Junct Off, Grand Junction, CO 81506 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. US EPA, Natl Risk Management Lab, Ada, OK 74821 USA. USN, NFESC, Port Hueneme, CA 93403 USA. RP Korte, N (reprint author), Oak Ridge Natl Lab, Grand Junct Off, Grand Junction, CO 81506 USA. RI Gu, Baohua/B-9511-2012; Liang, Liyuan/O-7213-2014 OI Gu, Baohua/0000-0002-7299-2956; Liang, Liyuan/0000-0003-1338-0324 NR 58 TC 90 Z9 93 U1 2 U2 19 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1093-0191 J9 ADV ENVIRON RES JI Adv. Environ. Res. PD NOV PY 2000 VL 4 IS 4 BP 273 EP 286 DI 10.1016/S1093-0191(00)00026-5 PG 14 WC Engineering, Environmental; Engineering, Chemical SC Engineering GA 383WC UT WOS:000165906500001 ER PT J AU Liu, C Ball, WP AF Liu, C Ball, WP TI Analytical modeling of diffusion-limited contamination and decontamination in a two-layer porous medium (vol 21, pg 297, 1998) SO ADVANCES IN WATER RESOURCES LA English DT Correction C1 Johns Hopkins Univ, Dept Geog & Environm Sci, Baltimore, MD 21218 USA. RP Liu, C (reprint author), Pacific NW Natl Lab, EMSL, POB 999,K8-96, Richland, WA 99352 USA. RI Ball, William/A-3285-2010; Liu, Chongxuan/C-5580-2009 OI Ball, William/0000-0001-5217-8108; NR 1 TC 0 Z9 0 U1 1 U2 5 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 NOV PY 2000 VL 24 IS 2 BP 225 EP 225 DI 10.1016/S0309-1708(00)00049-X PG 1 WC Water Resources SC Water Resources GA 391HY UT WOS:000166351600010 ER PT J AU Strom, DJ Stansbury, PS AF Strom, DJ Stansbury, PS TI Determining parameters of lognormal distributions from minimal information SO AIHAJ LA English DT Article DE aerosol size distribution; computer program; environmental health; lognormal distribution; parameters; probabilistic risk assessment AB The lognormal distribution has a number of properties that do not lend themselves to simple "back-of-the-envelope" calculations. Mathematical relationships are presented for the basic parameters of the large population lognormal distribution as a function of characteristics available to, or needed by, the risk analyst. A freeware computer program called LOGNORM4 has been written to take the tedium out of determining various characteristics of lognormal distributions, given 1 of 15 sets of values that uniquely specify a lognormal distribution. C1 Pacific NW Natl Lab, Risk Anal & Hlth Protect Grp, Richland, WA 99352 USA. RP Strom, DJ (reprint author), Pacific NW Natl Lab, Risk Anal & Hlth Protect Grp, Battelle Blvd,POB 999, Richland, WA 99352 USA. NR 8 TC 10 Z9 10 U1 0 U2 1 PU AMER INDUSTRIAL HYGIENE ASSOC PI FAIRFAX PA 2700 PROSPERITY AVE #250, FAIRFAX, VA 22031-4307 USA SN 1529-8663 J9 AIHAJ JI AIHAJ PD NOV-DEC PY 2000 VL 61 IS 6 BP 877 EP 880 DI 10.1202/0002-8894(2000)061<0877:DPOLDF>2.0.CO;2 PG 4 WC Environmental Sciences; Public, Environmental & Occupational Health SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health GA 390FX UT WOS:000166286000015 PM 11192223 ER PT J AU Kuiken, C Thakallapalli, R Eskild, A de Ronde, A AF Kuiken, C Thakallapalli, R Eskild, A de Ronde, A TI Genetic analysis reveals epidemiologic patterns in the spread of human immunodeficiency virus SO AMERICAN JOURNAL OF EPIDEMIOLOGY LA English DT Article DE disease transmission; genetic heterogeneity; genetics; HIV; viruses ID INJECTING DRUG-USERS; HIV TYPE-1 SUBTYPE; COMMERCIAL SEX WORKERS; V3 LOOP SEQUENCES; MOLECULAR EPIDEMIOLOGY; SEROLOGIC CHARACTERIZATION; PHYLOGENETIC ANALYSIS; IMMUNE-DEFICIENCY; ENVELOPE PROTEIN; HIGH PREVALENCE AB The extreme variability of human immunodeficiency virus type 1 (HIV-1) makes it possible to conduct transmission studies on the basis of genetic analysis and to trace global and local patterns in the spread of the virus. Two such patterns are discussed in this paper. First, in many European countries (e.g., Scotland and Germany), homosexual men tend to be infected with a subtly different variant of HIV-1 than intravenous drug users. In other European countries (e.g., Norway and Sweden), a distinction is also found between the two risk groups; but based on available data, the distinction is a different one. The second pattern is a worldwide tendency for homosexual men in many different geographic regions around the world to carry HIV-1 subtype B, the variant that is most prevalent in the Americas, Europe, and Australia. In contrast, people infected via other routes (mostly heterosexual contact) in those same countries carry a mixture of other subtypes, Biologic differences between the viruses infecting different risk groups have not been found; the most likely explanation for the findings is different epidemiologic patterns. Although data are still scarce, the authors attempt to use these patterns in the reconstruction of the worldwide spread of the HIV epidemic. C1 Univ Calif Los Alamos Natl Lab, Grp T10, Theoret Biol & Biophys Grp, Los Alamos, NM 87545 USA. Natl Inst Publ Hlth, Oslo, Norway. Univ Amsterdam, Acad Med Ctr, Dept Human Retrovirol, NL-1105 AZ Amsterdam, Netherlands. RP Kuiken, C (reprint author), Univ Calif Los Alamos Natl Lab, Grp T10, Theoret Biol & Biophys Grp, Mail Stop K710, Los Alamos, NM 87545 USA. NR 77 TC 41 Z9 46 U1 0 U2 2 PU OXFORD UNIV PRESS INC PI CARY PA JOURNALS DEPT, 2001 EVANS RD, CARY, NC 27513 USA SN 0002-9262 J9 AM J EPIDEMIOL JI Am. J. Epidemiol. PD NOV 1 PY 2000 VL 152 IS 9 BP 814 EP 822 DI 10.1093/aje/152.9.814 PG 9 WC Public, Environmental & Occupational Health SC Public, Environmental & Occupational Health GA 369ZN UT WOS:000165097800005 PM 11085392 ER PT J AU Fowler, JS Wang, GJ Volkow, ND Franceschi, D Logan, J Pappas, N Shea, C MacGregor, RR Garza, V AF Fowler, JS Wang, GJ Volkow, ND Franceschi, D Logan, J Pappas, N Shea, C MacGregor, RR Garza, V TI Maintenance of brain monoamine oxidase B inhibition in smokers after overnight cigarette abstinence SO AMERICAN JOURNAL OF PSYCHIATRY LA English DT Article AB Objective: The authors' goal was to replicate a previous finding that smokers have lower brain monoamine oxidase B (MAO-B) levels than comparison nonsmoking subjects and to determine if levels recover after overnight cigarette abstinence. Method: Brain MAO-B levels were measured by means of positron emission tomography in six smokers who were scanned twice: 11.3 hours (baseline) and 10 minutes after smoking one cigarette. Results: Average MAO-B levels in smokers in the present study were similar to those found in the previous study and averaged 39% (SD=17) lower than those found in a comparison group of nonsmokers. Brain MAO-B levels did not differ between baseline levels and 10 minutes after smoking. Conclusions: This study reinforces the need to investigate whether MAO-B inhibition may account for some of the behavioral and epidemiological features of smoking. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. SUNY Stony Brook, Dept Psychiat, Stony Brook, NY 11794 USA. RP Fowler, JS (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. FU NIDA NIH HHS [DA-06278]; NINDS NIH HHS [NS-15380] NR 11 TC 41 Z9 43 U1 1 U2 4 PU AMER PSYCHIATRIC PRESS, INC PI WASHINGTON PA 1400 K ST, N W, STE 1101, WASHINGTON, DC 20005 USA SN 0002-953X J9 AM J PSYCHIAT JI Am. J. Psychiat. PD NOV PY 2000 VL 157 IS 11 BP 1864 EP 1866 DI 10.1176/appi.ajp.157.11.1864 PG 3 WC Psychiatry SC Psychiatry GA 369YJ UT WOS:000165095100025 PM 11058487 ER PT J AU Yan, XM Habbersett, RC Cordek, JM Nolan, JP Yoshida, TM Jett, JH Marrone, BL AF Yan, XM Habbersett, RC Cordek, JM Nolan, JP Yoshida, TM Jett, JH Marrone, BL TI Development of a mechanism-based, DNA staining protocol using SYTOX orange nucleic acid stain and DNA fragment sizing flow cytometry SO ANALYTICAL BIOCHEMISTRY LA English DT Article DE intercalating dye; flow cytometry; DNA sizing; fluorescence; dissociation constant ID DOUBLE-STRANDED DNA; FLUORESCENT INTERCALATING DYES; CAPILLARY-ELECTROPHORESIS; SENSITIVITY; MOLECULES; COMPLEXES; BINDING; SPECTROSCOPY; PROBES; YOYO AB Accurate measurement of single DNA fragments by DNA fragment sizing flow cytometry (FSFC) depends upon precise, stoichiometric DNA staining by the intercalating dye molecules, In this study, we determined the binding characteristics of a commercially available 532 nm wavelength-excitable dye and used this information to develop a universal DNA staining protocol for DNA FSFC using a compact frequency-doubled Nd:YAG laser excitation source. Among twelve 532 nm wavelength-excitable nucleic acid staining dyes tested, SYTOX Orange stain showed the highest fluorescence intensity along with a large fluorescence enhancement upon binding to double-stranded DNA (similar to 450-fold). Furthermore, using SYTOX Orange stain, accurate fragment-size-distribution histograms were consistently obtained without regard to the staining dye to base pair (dye/bp) ratio. A model describing two binding modes, intercalation (primary, yielding fluorescence) and external binding (secondary, involving fluorescence quenching), was proposed to interpret the performance of the dyes under different dye/bp ratios, The secondary equilibrium dissociation constant was found to be the most critical parameter in determining the sensitivity of each fluorophore to the staining dye/bp ratio, The measurements of both equilibrium dissociation constants provided us with a theoretical framework for developing a universal protocol which was successfully demonstrated over a wide range of DNA concentrations on a compact flow cytometer equipped with a frequency-doubled, diode-pumped, solid-state Nd:YAG laser for rapid and sensitive DNA fragment sizing, (C) 2000 Academic Press. C1 Univ Calif Los Alamos Natl Lab, Biosci Div, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Marrone, BL (reprint author), Univ Calif Los Alamos Natl Lab, Biosci Div, MS M888, Los Alamos, NM 87545 USA. FU OCPHP CDC HHS [PR-01315] NR 31 TC 35 Z9 38 U1 3 U2 12 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0003-2697 J9 ANAL BIOCHEM JI Anal. Biochem. PD NOV 1 PY 2000 VL 286 IS 1 BP 138 EP 148 DI 10.1006/abio.2000.4789 PG 11 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 371WA UT WOS:000165201200018 PM 11038284 ER PT J AU Miyabe, K Guiochon, G AF Miyabe, K Guiochon, G TI A kinetic study of mass transfer in reversed-phase liquid chromatography on a C18-silica gel SO ANALYTICAL CHEMISTRY LA English DT Article ID TRANSFER RATE COEFFICIENT; CONCENTRATION-DEPENDENCE; CELLULOSE TRIACETATE; LATERAL DIFFUSION; SURFACE-DIFFUSION; LIGHT-SCATTERING; FRONTAL ANALYSIS; TROGERS BASE; INTERFACE; SOLUTES AB The characteristic features of mass-transfer kinetics in a reversed-phase (RP) column packed with a C18-silica were studied. The relevant information on phase equilibrium thermodynamics and mass-transfer kinetics was obtained by frontal analysis and the pulse method, respectively. The equilibrium isotherm was accounted for by the simple Langmuir model. The ratio of the axial dispersion coefficient to the mobile-phase now velocity increased almost linearly with increasing solute concentration. Similarly, the mass-transfer rate coefficient (k(m)) showed a linear dependence on the solute concentration. The positive concentration dependence of k(m) resulted from that of the surface diffusion coefficient, which was interpreted with the chemical potential driving force model. The contribution of axial dispersion to band broadening was predominant in the RP column packed with the medium-size packing material used (particle diameter, 12 mum) whereas that of the kinetics of adsorption/desorption was negligibly small, The results of this study demonstrate how an analysis of the dependence of the mass-transfer kinetics on the flow velocity and the solute concentration allows a better understanding of this kinetics. 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 43 TC 39 Z9 39 U1 0 U2 5 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 NOV 1 PY 2000 VL 72 IS 21 BP 5162 EP 5171 DI 10.1021/ac0002801 PG 10 WC Chemistry, Analytical SC Chemistry GA 369XX UT WOS:000165094000011 ER PT J AU Rocklin, RD Ramsey, RS Ramsey, JM AF Rocklin, RD Ramsey, RS Ramsey, JM TI A microfabricated fluidic device for performing two-dimensional liquid-phase separations SO ANALYTICAL CHEMISTRY LA English DT Article ID MICELLAR ELECTROKINETIC CHROMATOGRAPHY; OPEN-CHANNEL ELECTROCHROMATOGRAPHY; CAPILLARY ELECTROPHORESIS; PCR AMPLIFICATION; MICROCHIP DEVICE; CHIPS AB A microfabricated fluidic device that combines micellar electrokinetic chromatography and high-speed open-channel electrophoresis on a single structure for the rapid automated two-dimensional analysis of peptides has been devised and demonstrated. The microchip operates by rapidly sampling and analyzing effluent in the second dimension from the first dimension. Second-dimension analyses are performed and completed every few seconds, with total analysis times of less than 10 min for tryptic peptides. The peak capacity of the two-dimensional separations has been estimated to be in the 500-1000 range. The orthogonality of the separation techniques, an important factor for maximizing peak capacity or resolution elements, was verified by examining each technique independently for peptide separations. The two-dimensional separation strategy was found to greedy increase the resolving power over that obtained for either dimension alone. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Caliper Technol Corp, Mt View, CA 94043 USA. RP Ramsey, JM (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. FU NCI NIH HHS [CA 83238-02] NR 27 TC 168 Z9 174 U1 2 U2 20 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 NOV 1 PY 2000 VL 72 IS 21 BP 5244 EP 5249 DI 10.1021/ac000578r PG 6 WC Chemistry, Analytical SC Chemistry GA 369XX UT WOS:000165094000023 PM 11080871 ER PT J AU Kavallieratos, K Danby, A Van Berkel, GJ Kelly, MA Sachleben, RA Moyer, BA Bowman-James, K AF Kavallieratos, K Danby, A Van Berkel, GJ Kelly, MA Sachleben, RA Moyer, BA Bowman-James, K TI Enhanced of CsNO3 extraction in 1,2-dichloroethane by tris(2-aminoethyl)amine triamide derivatives via a dual-host strategy SO ANALYTICAL CHEMISTRY LA English DT Article ID ETHER CARBOXYLIC-ACID; ION-PAIR EXTRACTION; ALKALI-METAL IONS; SOLVENT-EXTRACTION; CROWN-ETHER; DIDODECYLNAPHTHALENESULFONIC ACID; 1,3-ALTERNATE CONFORMATION; MACROCYCLIC POLYETHERS; SELECTIVE EXTRACTION; AQUEOUS-SOLUTIONS AB A systematic study of a dual-host system exhibiting pairwise anion/cation separations has been performed for CsNO3 extraction. Tripodal triamides 1-4 and 9 derived from condensation of hexanoic (for 1), octanoic (for 2), decanoic (for 3), lauric (for 4), and p-tert-butylbenzoic (for 9) acid with tris(2-aminoethyl)amine (tren) were used together with tetrabenzo-24-crown-8, a well-known Cs+ cation receptor. By using 5 mill crown ether in the organic phase and 10 mM CsNO3 with 0.1 mM HNO3 in the aqueous phase, tripods 1, 2, and 9 enhance CsNO3 extraction by factors of 2.4, 1.7, and 4.4, respectively (for 50 mM amide concentration), while the corresponding monoamide controls 5-8 derived from n-propylamine (5, 6) or N,N'-dimethylethylenediamine (7, 8) and hexanoic (5, 7) or octanoic (6, 8) acid derivatives gave no significant enhancement under the same conditions. This behavior may be ascribed to nitrate complexation by the triamides, which lowers the overall thermodynamic barrier for the salt transfer to the organic phase. The nitrate binding was confirmed by H-1 NMR titration of receptor solutions, using tetrabutylammonium nitrate. Association constants for the formation of the anion-nitrate complexes were found to vary between 33 and 52 M-1 for the more soluble triamides, The synergistic effects for CsNO3 extraction are in reasonable agreement with the values predicted theoretically from the measured association constants. Electrospray ionization mass spectrometry confirmed the predominant formation of 1:1 tripod-nitrate complexes. Monoamide controls gave no evidence of anion complexation. C1 Univ Kansas, Dept Chem, Lawrence, KS 66045 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Chem Separat Grp, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Organ & Biol Mass Spectrometry Grp, Oak Ridge, TN 37831 USA. RP Moyer, BA (reprint author), Univ Kansas, Dept Chem, Lawrence, KS 66045 USA. RI Solominow, Sonia/A-4021-2008; Moyer, Bruce/L-2744-2016 OI Moyer, Bruce/0000-0001-7484-6277 NR 85 TC 56 Z9 56 U1 1 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD NOV 1 PY 2000 VL 72 IS 21 BP 5258 EP 5264 DI 10.1021/ac0005971 PG 7 WC Chemistry, Analytical SC Chemistry GA 369XX UT WOS:000165094000025 ER PT J AU Martinovic, S Berger, SJ Pasa-Tolic, L Smith, RD AF Martinovic, S Berger, SJ Pasa-Tolic, L Smith, RD TI Separation and detection of intact noncovalent protein complexes from mixtures by on-line capillary isoelectric focusing-mass spectrometry SO ANALYTICAL CHEMISTRY LA English DT Article ID ELECTROSPRAY-IONIZATION; IDENTIFICATION; BINDING; ELECTROPHORESIS; BIOMOLECULES; ASSOCIATIONS; LIGANDS; YEAST AB Separation and mass spectrometric analysis of intact noncovalent protein-protein complexes from mixtures is described. Protein complexes were separated using isoelectric focusing in a capillary under native conditions. During the mobilization, molecular masses of the intact complexes were measured on-line (as they emerged from the capillary) using Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. An FTICR "in-trap" ion cleanup procedure was necessary for some complexes to reduce high levels of adduction and to obtain accurate molecular mass measurements. Optimization of the conditions for analysis of different intact complexes is discussed. We have shown that either the intact noncovalent complexes or their constituent protein subunits can be detected by variation of sheath liquid (i.e., NH4OAc vs HOAc) added at the electrospray-mass spectrometer interface. Thus, two successive experiments permit a fast and efficient characterization of intact complex stoichiometry, the individual complex subunits and the possible presence of metal or other adducted species. C1 Pacific NW Natl Lab, Environm & Mol Sci Lab, Richland, WA 99352 USA. RP Smith, RD (reprint author), Pacific NW Natl Lab, Environm & Mol Sci Lab, POB 999, Richland, WA 99352 USA. RI Smith, Richard/J-3664-2012 OI Smith, Richard/0000-0002-2381-2349 NR 45 TC 48 Z9 48 U1 1 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD NOV 1 PY 2000 VL 72 IS 21 BP 5356 EP 5360 DI 10.1021/ac0004557 PG 5 WC Chemistry, Analytical SC Chemistry GA 369XX UT WOS:000165094000039 PM 11080887 ER PT J AU Griffiths, SK Nilson, RH AF Griffiths, SK Nilson, RH TI Band spreading in two-dimensional microchannel turns for electrokinetic species transport SO ANALYTICAL CHEMISTRY LA English DT Article ID OPEN-CHANNEL ELECTROCHROMATOGRAPHY; CAPILLARY-ZONE-ELECTROPHORESIS; SEPARATIONS; CHIPS; DNA; SYSTEMS; GLASS; CHROMATOGRAPHY; DISPERSION; MICROCHIPS AB Analytical and numerical methods are employed to investigate species transport by electrophoretic or electroosmotic motion in the curved geometry of a tno-dimensional turn. Closed-form analytical solutions describing the turn-induced diffusive and dispersive spreading of a species band are presented for both the low and high Peclet number limits. We find that the spreading due to dispersion is proportional to the product of the turn included angle and the Peclet number at low Peclet numbers. It is proportional to the square of the included angle and independent of the Peclet number when the Peclet number is large. A composite solution applicable to all Peclet numbers is constructed from these limiting behaviors. Numerical solutions for species transport in a turn are also presented over a wide range of the included angle and the mean turn radius. On the basis of comparisons between the analytical and numerical results, we find that the analytical solutions provide very good estimates of both dispersive and diffusive spreading provided that the mean turn radius exceeds the channel width. These new solutions also agree well with data from a previous study. Optimum conditions minimizing total spreading in a turn are presented and discussed. C1 Sandia Natl Labs, Livermore, CA 94551 USA. RP Griffiths, SK (reprint author), Sandia Natl Labs, POB 969, Livermore, CA 94551 USA. NR 39 TC 75 Z9 76 U1 0 U2 5 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 NOV 1 PY 2000 VL 72 IS 21 BP 5473 EP 5482 DI 10.1021/ac000595g PG 10 WC Chemistry, Analytical SC Chemistry GA 369XX UT WOS:000165094000055 ER PT J AU Yost, TL Fagan, BC Allain, LR Barnes, CE Dai, S Sepaniak, MJ Xue, ZL AF Yost, TL Fagan, BC Allain, LR Barnes, CE Dai, S Sepaniak, MJ Xue, ZL TI Crown ether-doped sol-gel materials for strontium(II) separation SO ANALYTICAL CHEMISTRY LA English DT Article ID SILICA-GEL; MESOPOROUS SUPPORTS; IMMOBILIZATION; SELECTIVITY; MONOLAYERS; MEMBRANES; CATIONS; METALS AB Hybrid organic/inorganic sol-gel materials containing an encapsulated crown ether ligand were found to selectively remove 91.4 +/- 1.3% of Sr2+ from a solution containing excess of competing ions such as Ca2+. The crown ether ligand, 1,4,10,13-tetraoxa-7,1 6-diazacyclooctadecane-7, 16-bis(malonate) ligand (Na(4)oddm), with known high affinity for Sr2+ was encapsulated in hydrophilic SiO2 through a simple sol-gel process. Washing the Sr2+-loaded gel with acid or ethylenediaminetetraacetic acid disodium salt recovered the Sr2+ from the sol-gel sorbent and regenerated the doped gel for subsequent Sr2+ intake. The approach reported here is a new alternative to the use of crown ethers in metal ion separation through, for example, solvent extraction or the use of sorbents containing chemically grafted crown ether ligands. C1 Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. RP Xue, ZL (reprint author), Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. RI Dai, Sheng/K-8411-2015 OI Dai, Sheng/0000-0002-8046-3931 NR 42 TC 36 Z9 38 U1 3 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD NOV 1 PY 2000 VL 72 IS 21 BP 5516 EP 5519 DI 10.1021/ac0005518 PG 4 WC Chemistry, Analytical SC Chemistry GA 369XX UT WOS:000165094000061 ER PT J AU Van Fleet-Stalder, V Chasteen, TG Pickering, IJ George, GN Prince, RC AF Van Fleet-Stalder, V Chasteen, TG Pickering, IJ George, GN Prince, RC TI Fate of selenate and selenite metabolized by Rhodobacter sphaeroides SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID FLUORINE-INDUCED CHEMILUMINESCENCE; RAY-ABSORPTION SPECTROSCOPY; BACTERIAL CULTURES; REDUCING BACTERIA; DIMETHYL SELENONE; OXYANIONS; BIOAVAILABILITY; IDENTIFICATION; SPECIATION; CALIFORNIA AB Cultures of a purple nonsulfur bacterium, Rhodobacter sphaeroides, amended with similar to1 or similar to 100 ppm selenate or selenite, were grown phototrophically to stationary phase. Analyses of culture headspace, separated cells, and filtered culture supernatant were carried out using gas chromatography, X-ray absorption spectroscopy, and inductively coupled plasma spectroscopy-mass spectrometry, respectively. While selenium-amended cultures showed much higher amounts of SeO32- bioconversion than did analogous selenate experiments (94% uptake for SeO32- as compared to 9.6% for SeO32--amended cultures from 100-ppm solutions), the chemical forms of selenium in the microbial cells were not very different except at exposure to high concentrations of selenite. Volatilization accounted for only a very small portion of the accumulated selenium; most was present in organic forms and the red elemental form. C1 Sam Houston State Univ, Dept Chem, Huntsville, TX 77341 USA. Sam Houston State Univ, Texas Res Inst Environm Studies, Huntsville, TX 77341 USA. Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. ExxonMobil Res & Engn Co, Annandale, NJ 08801 USA. RP Chasteen, TG (reprint author), Sam Houston State Univ, Dept Chem, POB 2117, Huntsville, TX 77341 USA. RI Chasteen, Thomas/B-6601-2009; George, Graham/E-3290-2013; Pickering, Ingrid/A-4547-2013; OI Pickering, Ingrid/0000-0002-0936-2994 NR 26 TC 44 Z9 45 U1 1 U2 5 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD NOV PY 2000 VL 66 IS 11 BP 4849 EP + DI 10.1128/AEM.66.11.4849-4853.2000 PG 6 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 369FM UT WOS:000165055300036 PM 11055934 ER PT J AU Kennedy, CA Carpenter, MH Lewis, RM AF Kennedy, CA Carpenter, MH Lewis, RM TI Low-storage, explicit Runge-Kutta schemes for the compressible Navier-Stokes equations SO APPLIED NUMERICAL MATHEMATICS LA English DT Article ID PARTIAL-DIFFERENTIAL EQUATIONS; INITIAL-VALUE PROBLEMS; BOUNDARY-LAYER FLOWS; NUMERICAL-SOLUTION; COMPUTATIONAL ACOUSTICS; OSCILLATING SOLUTIONS; LOW-DISSIPATION; PAIRS; STABILITY; ERROR AB The derivation of low-storage, explicit Runge-Kutta (ERK) schemes has been performed in the context of integrating the compressible Navier-Stokes equations via direct numerical simulation. Optimization of ERK methods is done across the broad range of properties, such as stability and accuracy efficiency, linear and nonlinear stability, error control reliability, step change stability, and dissipation/dispersion accuracy, subject to varying degrees of memory economization. Following van der Houwen and Wray, sixteen ERK pairs are presented using from two to five registers of memory per equation, per grid point and having accuracies from third- to fifth-order. Methods have been tested with not only DETEST, but also with the 1D wave equation. Two of the methods have been applied to the DNS of a compressible jet as well as methane-air and hydrogen-air flames. Derived 3(2) End 4(3) pairs are competitive with existing full-storage methods. Although a substantial efficiency penalty accompanies use of two- and three-register, fifth-order methods, the best contemporary full-storage methods can be nearly matched while still saving 2-3 registers of memory. (C) 2000 IMACS. Published by Elsevier Science B.V. All rights reserved. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. NASA, Langley Res Ctr, Computat Methods & Simulat Branch, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Inst Comp Applicat Sci & Engn, Hampton, VA 23681 USA. RP Kennedy, CA (reprint author), Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. NR 93 TC 179 Z9 182 U1 1 U2 13 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9274 J9 APPL NUMER MATH JI Appl. Numer. Math. PD NOV PY 2000 VL 35 IS 3 BP 177 EP 219 DI 10.1016/S0168-9274(99)00141-5 PG 43 WC Mathematics, Applied SC Mathematics GA 371BJ UT WOS:000165157500001 ER PT J AU Timinger, A Kribus, A Ries, H Smith, T Walther, M AF Timinger, A Kribus, A Ries, H Smith, T Walther, M TI Optical assessment of nonimaging concentrators SO APPLIED OPTICS LA English DT Article ID SOLAR AB An optical measurement method for nonimaging radiation concentrators is proposed. A Lambertian Light source is placed in the exit aperture of the concentrator. Looking into the concentrator's entrance aperture from a remote position, one can photograph the transmission patterns. The patterns show the transmission of radiation through the concentrator with the full resolution of the four-dimensional phase space of geometric optics. By matching ray-tracing simulations to the measurement, one can achieve detailed and accurate information about the geometry of the concentrator. This is a remote, noncontact measurement and can be performed in situ for installed concentrators. Additional information regarding small-scale reflector waviness and surface reflectivity can also be obtained from the same measurement with additional analysis. (C) 2000 Optical Society of America. OCIS codes: 000.4430, 080.2740, 120.7000, 120.4290. C1 Opt & Energy Concepts, D-80686 Munich, Germany. Weizmann Inst Sci, Dept Environm Sci & Energy Res, IL-76100 Rehovot, Israel. Natl Renewable Energy Lab, Ctr Bldg & Thermal Syst, Golden, CO 80401 USA. RP Timinger, A (reprint author), Opt & Energy Concepts, Stoeberlstr 68, D-80686 Munich, Germany. RI Kribus, Abraham/D-5588-2009 OI Kribus, Abraham/0000-0003-2296-3556 NR 13 TC 7 Z9 7 U1 0 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD NOV 1 PY 2000 VL 39 IS 31 BP 5679 EP 5684 DI 10.1364/AO.39.005679 PG 6 WC Optics SC Optics GA 369EJ UT WOS:000165052800004 PM 18354564 ER PT J AU Lee, SH Naulleau, P Goldberg, KA Piao, F Oldham, W Bokar, J AF Lee, SH Naulleau, P Goldberg, KA Piao, F Oldham, W Bokar, J TI Phase-shifting point-diffraction interferometry at 193 nm SO APPLIED OPTICS LA English DT Article ID FUSED-SILICA; INDUCED DENSIFICATION; ULTRAVIOLET; COMPACTION; ACCURACY AB Phase-shifting point-diffraction interferometry at the 193-nm wavelength suitable for highly accurate measurement of wave-front aberration is introduced. The interferometer preserves the advantages of the previously described extreme-ultraviolet phase-shifting point-diffraction interferometer but offers higher relative efficiency. Wave-front measurement of an imaging system, operating at the 193-nm wavelength, is reported. Direct measurement of the refractive-index change in a deep-ultraviolet radiation-damaged fused-silica sample is also presented as an application. (C) 2000 Optical Society of America OCIS codes: 120.3180, 050.5080, 120.3940, 120.5050, 030.1640, 350.2770, 110.3960. C1 Univ Calif Berkeley, Dept Elect Engn & Comp Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. RP Lee, SH (reprint author), Univ Calif Berkeley, Dept Elect Engn & Comp Sci, Berkeley, CA 94720 USA. EM shlee@lbl.gov NR 15 TC 12 Z9 14 U1 0 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD NOV 1 PY 2000 VL 39 IS 31 BP 5768 EP 5772 DI 10.1364/AO.39.005768 PG 5 WC Optics SC Optics GA 369EJ UT WOS:000165052800016 PM 18354576 ER PT J AU Vanderberg, LA AF Vanderberg, LA TI Detection of biological agents: Looking for bugs in all the wrong places SO APPLIED SPECTROSCOPY LA English DT Review ID SURFACE-PLASMON RESONANCE; FT-IR SPECTROSCOPY; TRANSFORM INFRARED-SPECTROSCOPY; RAMAN-SPECTROSCOPY; FLUORESCENCE; BACTERIA; WARFARE; CELLS; IDENTIFICATION; MANAGEMENT C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Vanderberg, LA (reprint author), Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 69 TC 32 Z9 32 U1 1 U2 4 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA 5320 SPECTRUM DRIVE SUITE C, FREDERICK, MD 21703 USA SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD NOV PY 2000 VL 54 IS 11 BP 376A EP 385A PG 10 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA 379LR UT WOS:000165644000002 ER PT J AU Schneider, DP Fan, XH Strauss, MA Gunn, JE Richards, GT Knapp, GR Lupton, RH Saxe, DH Anderson, JE Bahcall, NA Brinkmann, J Brunner, R Csabai, I Fukugita, M Hennessy, GS Hindsley, RB Ivezic, Z Nichol, RC Pier, JR York, DG AF Schneider, DP Fan, XH Strauss, MA Gunn, JE Richards, GT Knapp, GR Lupton, RH Saxe, DH Anderson, JE Bahcall, NA Brinkmann, J Brunner, R Csabai, I Fukugita, M Hennessy, GS Hindsley, RB Ivezic, Z Nichol, RC Pier, JR York, DG TI Discovery of a pair of z=4.25 quasars from the Sloan Digital Sky Survey SO ASTRONOMICAL JOURNAL LA English DT Article DE early universe; quasars : individual ID HOBBY-EBERLY TELESCOPE; LOW-RESOLUTION SPECTROGRAPH; SURVEY COMMISSIONING DATA; HIGH-REDSHIFT QUASARS; TRANSIT GRISM SURVEY; SERENDIPITOUS DISCOVERY; LUMINOSITY FUNCTION; EMISSION; EVOLUTION; SYSTEM AB We report the discovery of a pair of z = 4.25 quasars with a separation of 33 ". The brighter of the two objects was identified as a high-redshift quasar candidate from Sloan Digital Sky Survey multicolor imaging data, and the redshift was measured from a spectrum obtained with the Hobby-Eberly Telescope. The slit orientation of this observation by chance included another quasar, approximately 1 mag fainter and having the same redshift as the target. This is the third serendipitous discovery of a z > 4 quasar. The differences in the relative strengths and profiles of the emission lines suggest that this is a quasar pair and not a gravitational lens. The two objects are likely to be physically associated; the projected physical separation is approximately 210 h(50)(-1) kpc and the redshifts are identical to approximate to0.01, implying a radial physical separation of 950 h(50)(-1) kpc or less. The existence of this pair is strong circumstantial evidence that z similar to 4 quasars are clustered. C1 Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Princeton Univ Observ, Princeton, NJ 08544 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Inst Adv Study, Princeton, NJ 08540 USA. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Apache Point Observ, Sunspot, NM 88349 USA. CALTECH, Dept Astron, Pasadena, CA 91125 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Eotvos Lorand Univ, Dept Phys Complex Syst, H-1117 Budapest, Hungary. Univ Tokyo, Inst Cosm Ray Res, Midori Ku, Tanashi, Tokyo 1888588, Japan. USN Observ, Washington, DC 20392 USA. USN, Res Lab, Remote Sensing Div, Washington, DC 20375 USA. Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15213 USA. USN Observ, Flagstaff Stn, Flagstaff, AZ 86002 USA. RP Schneider, DP (reprint author), Penn State Univ, Dept Astron & Astrophys, 525 Davey Lab, University Pk, PA 16802 USA. EM dps@astro.psu.edu; fan@astro.princeton.edu; strauss@astro.princeton.edu RI Csabai, Istvan/F-2455-2012; OI Csabai, Istvan/0000-0001-9232-9898 NR 38 TC 20 Z9 20 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD NOV PY 2000 VL 120 IS 5 BP 2183 EP 2189 DI 10.1086/316834 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 369YK UT WOS:000165095200001 ER PT J AU de Vries, WH O'Dea, CP Barthel, PD Fanti, C Fanti, R Lehnert, MD AF de Vries, WH O'Dea, CP Barthel, PD Fanti, C Fanti, R Lehnert, MD TI Hubble Space Telescope NICMOS observations of the host galaxies of powerful radio sources: Does size matter? SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : nuclei; infrared radiation ID COMPACT STEEP-SPECTRUM; GIGAHERTZ PEAKED-SPECTRUM; ACTIVE GALACTIC NUCLEI; SURFACE PHOTOMETRY; ELLIPTICAL GALAXIES; SYMMETRICAL OBJECTS; SOURCE EVOLUTION; CLUSTERS; VLA; DIAGRAM AB We present near-infrared J- and K-band imaging of a sample of powerful radio source host galaxies with the Hubble Space Telescope NICMOS2 camera. These sources have been selected on their double-lobed radio structure and include a wide range of projected radio source sizes. The largest projected linear sizes range from the compact gigahertz peaked spectrum (GPS; <1 kpc) and compact steep spectrum (CSS; <20 kpc) radio sources, up to the large-scale (>20 kpc) classical doubles (FR II radio sources). We investigate the dependence of host galaxy properties (including near-IR surface brightness profiles) on radio source size, using both our own and published data. The absolute magnitudes and surface brightness profiles are consistent with the host galaxies being regular giant elliptical galaxies rather than brightest cluster galaxies (BCGs). We find that the GPS, CSS, and FR II host galaxies are a uniform class of objects, consistent with a scenario in which a powerful radio source evolves along this size sequence. C1 Univ Calif Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Kapteyn Astron Inst, NL-9700 AV Groningen, Netherlands. Univ Bologna, I-40126 Bologna, Italy. MPE, D-85740 Garching, Germany. RP de Vries, WH (reprint author), Univ Calif Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. NR 65 TC 34 Z9 34 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 NOV PY 2000 VL 120 IS 5 BP 2300 EP 2330 DI 10.1086/316825 PG 31 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 369YK UT WOS:000165095200009 ER PT J AU Finlator, K Ivezic, Z Fan, XH Strauss, MA Knapp, GR Lupton, RH Gunn, JE Rockosi, CM Anderson, JE Csabai, I Hennessy, GS Hindsley, RB McKay, TA Nichol, RC Schneider, DP Smith, JA York, DG AF Finlator, K Ivezic, Z Fan, XH Strauss, MA Knapp, GR Lupton, RH Gunn, JE Rockosi, CM Anderson, JE Csabai, I Hennessy, GS Hindsley, RB McKay, TA Nichol, RC Schneider, DP Smith, JA York, DG CA SDSS Collaboration TI Optical and infrared colors of stars observed by the Two Micron All Sky Survey and the Sloan Digital Sky Survey SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxy : stellar content ID SYSTEM; DWARFS; FIELDS; MODEL AB We discuss optical and infrared photometric properties of stars matched in the Two Micron All Sky Survey (2MASS) and the Sloan Digital Sky Survey (SDSS) commissioning data for similar to 50 deg(2) of sky along the celestial equator centered at l = 150 degrees, b = -60 degrees. About 98% (similar to 63,000) of objects listed in the 2MASS Point Source Catalog in the analyzed area are matched within 2 " to an SDSS source. The matched sources represent 8% of the similar to 800,000 SDSS sources in this area. They are predominantly red sources, as expected, and 15% of them are resolved in SDSS imaging data although they are detected as point sources in 2MASS data. The distribution of positional discrepancies for the matched sources and the astrometric statistics for the multiply observed SDSS sources imply that the astrometric accuracy of both surveys is about 0."1 per coordinate (rms). For about 14,000 stars with the smallest photometric errors (less than or similar to 10%) in both surveys, we present optical and infrared color-magnitude and color-color diagrams. We use optical (SDSS) colors to identify the stellar spectral sequence and show that stars of different spectral types can have similar infrared colors, thus making the classification of stars based on only 2MASS data very difficult. However, a broad separation into "early" and "late" spectral types (relative to type KO) is possible with a reliability of similar to 95% even with 2MASS colors alone. The distributions of matched sources in color-magnitude and color-color diagrams are compared with the predictions of a stellar population synthesis code. We find that the models are in fair overall agreement with the data. In particular, the total number counts agree to better than 10%, and the morphologies of the color-magnitude and color-color diagrams appear similar. The most significant discrepancies are found for the number ratio of "early" to "late" type stars (by about a factor of 2) and in the colors of M stars (up to 0.2 mag). The first disagreement indicates that some parameters of the standard Galactic structure model and/or initial mass function can be improved, and the second disagreement emphasizes known difficulties with the modeling of stellar atmospheres for cool stars. C1 Princeton Univ Observ, Princeton, NJ 08544 USA. Univ Chicago, Ctr Astron & Astrophys, Chicago, IL 60637 USA. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Eotvos Lorand Univ, Dept Physr Complex Syst, H-1117 Budapest, Hungary. USN Observ, Washington, DC 20392 USA. USN, Res Lab, Remote Sensing Div, Washington, DC 20375 USA. Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USA. Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15232 USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. RP Finlator, K (reprint author), Princeton Univ Observ, Princeton, NJ 08544 USA. RI Csabai, Istvan/F-2455-2012; McKay, Timothy/C-1501-2009; Finlator, Kristian/M-4809-2014; OI McKay, Timothy/0000-0001-9036-6150; Finlator, Kristian/0000-0002-0496-1656; Csabai, Istvan/0000-0001-9232-9898 NR 29 TC 103 Z9 103 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD NOV PY 2000 VL 120 IS 5 BP 2615 EP 2626 DI 10.1086/316824 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 369YK UT WOS:000165095200030 ER PT J AU Kurczynski, P Palmer, D Seifert, H Teegarden, BJ Gehrels, N Cline, TL Ramaty, R Hurley, K Madden, NW Pehl, RH AF Kurczynski, P Palmer, D Seifert, H Teegarden, BJ Gehrels, N Cline, TL Ramaty, R Hurley, K Madden, NW Pehl, RH TI High-resolution spectroscopy of gamma-ray bursts with the transient gamma-ray spectrometer SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts; instrumentation : detectors; line : identification ID LINE SEARCH; SPECTRAL FEATURES; CYCLOTRON; ABSORPTION; ASTRONOMY; REPEATERS AB A search for spectral lines in gamma-ray bursts detected with the Transient Gamma-Ray Spectrometer has been unable to confirm their existence. The spectrometer, aboard the Wind spacecraft, has detected gamma-ray bursts and other transients since 1995. We have performed a systematic search for narrow spectral lines in gamma-ray bursts detected with this instrument that augments and extends the results of a similar search of bursts detected with BATSE. This search procedure tests for statistically significant lines at all possible times and durations during a burst using the method of maximum likelihood and C-statistic. Simulations demonstrated the effectiveness of this procedure, particularly on Poisson distributed data, for distinguishing real features from statistical fluctuations. The most promising line candidates were consistent with chance fluctuations, given the large number of spectra searched. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94702 USA. RP Kurczynski, P (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 22 TC 3 Z9 3 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 NOV 1 PY 2000 VL 543 IS 1 BP 77 EP 89 DI 10.1086/317069 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 374XB UT WOS:000165368800007 ER PT J AU Deupree, RG AF Deupree, RG TI Two-dimensional hydrodynamic simulations of zero-age main-sequence convective cores SO ASTROPHYSICAL JOURNAL LA English DT Article DE convection; hydrodynamics; stars : interiors ID ARBITRARY ROTATION LAWS; TURBULENT COMPRESSIBLE CONVECTION; STELLAR EVOLUTION; HELIUM FLASH; CONSTRAINTS; OVERSHOOT; OPACITIES; MODELS; TESTS; STARS AB Two-dimensional, fully implicit hydrodynamic simulations of the structure and motion of convective cores are made on complete zero-age main-sequence stellar models between 1.2 and 20 M-.. The calculations present a picture of hydrogen-burning convective cores where the convective speeds are tens of kilometers per second and the superadiabatic excess may be quite large at various locations in the core at any time. However, when averaged over angle, radius, and time the superadiabatic excess is only about 10(-3), although the steps to obtain this number involve some uncertainties. Convective core overshooting occurs in all models. In units of the pressure scale height at the convective core boundary, the overshooting calculated is about 0.45H(p) for models above 3 M-., and it decreases to about 0.3H(p) for lower mass models. Part of this decrease arises from the increase in the pressure scale height at the convective core boundary as the convective core boundary approaches the center of the model while the model mass becomes small. However, using the actual e-folding distance for the pressure as the unit of measure, the overshooting still shows a small decrease for lower masses. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87544 USA. RP Deupree, RG (reprint author), Univ Calif Los Alamos Natl Lab, DX-7,MS-P947, Los Alamos, NM 87544 USA. NR 35 TC 22 Z9 22 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 1 PY 2000 VL 543 IS 1 BP 395 EP 405 DI 10.1086/317068 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 374XB UT WOS:000165368800039 ER PT J AU Lee, A Bloom, ED Petrosian, V AF Lee, A Bloom, ED Petrosian, V TI Properties of gamma-ray burst time profiles using pulse decomposition analysis SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE gamma rays : bursts; methods : data analysis ID EVOLUTION AB The time profiles of many gamma-ray bursts consist of distinct pulses, which offers the possibility of characterizing the temporal structure of these bursts using a. relatively small set of pulse shape parameters. This pulse decomposition analysis has previously been performed on a small sample of bright, long bursts using binned data from BATSE, which comes in several data types, and on a sample of short bursts using the BATSE time-tagged event (TTE) data type. We have developed an interactive pulse-fitting program using the phenomenological pulse model of Norris et al. and a maximum-likelihood fitting routine. We have used this program to analyze the time-to-spill (TTS) data for all bursts observed by BATSE up through trigger number 2000, in all energy channels for which TTS data is available. This represents a total of 211 distinct bursts analyzed in one or more energy channels. We present statistical information on the attributes of pulses comprising these bursts, including relations between pulse characteristics in different energy channels and the evolution of pulse characteristics through the course of a burst. We carry out simulations to determine the biases that our procedures may introduce. We find that pulses tend to have shorter rise times than decay times, and tend to be narrower and peak earlier at higher energies. We also find that pulse brightness, pulse width, and pulse hardness ratios do not evolve monotonically within bursts, but that the ratios of pulse rise times to decay times tend to decrease with time within bursts. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Stanford Univ, Ctr Space Sci & Astrophys, Stanford, CA 94305 USA. Stanford Univ, Astron Program, Stanford, CA 94305 USA. Stanford Univ, Dept Phys, Stanford, CA 94305 USA. RP Lee, A (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 19 TC 31 Z9 37 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD NOV PY 2000 VL 131 IS 1 BP 1 EP 19 DI 10.1086/317364 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 385ZY UT WOS:000166036100001 ER PT J AU Lee, A Bloom, ED Petrosian, V AF Lee, A Bloom, ED Petrosian, V TI On the intrinsic and cosmological signatures in gamma-ray burst time profiles: Time dilation SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE cosmology : theory; gamma rays : bursts AB The time profiles of many gamma-ray bursts consist of distinct pulses, which offers the possibility of characterizing the temporal structure of these bursts using a relatively small set of pulse shape parameters. We have used a pulse decomposition procedure to analyze the time-to-spill (TTS) data for all bursts observed by BATSE up through trigger number 2000, in all energy channels for which TTS data is available. We obtain amplitude, rise and decay timescales, a pulse shape parameter, and the fluences of individual pulses in all of the bursts. We investigate the correlations between brightness measures (amplitude and fluence) and timescale measures (pulse width and separation), which may result from cosmological time dilation of bursts, or from intrinsic properties of burst sources, or from selection effects. The effects of selection biases are evaluated through simulations. The correlations between these parameters among pulses within individual bursts give a measure of the intrinsic effects, while the correlations among bursts could result from both intrinsic and cosmological effects. We find that timescales tend to be shorter in bursts with higher peak fluxes, as expected from cosmological time-dilation effects, but we also find that there are noncosmological effects contributing to this inverse correlation. We find that timescales tend to be longer in bursts with higher total fluences, contrary to what is expected from cosmological effects. We also find that peak fluxes and total fluences of bursts are uncorrelated, indicating that they cannot both be good distance indicators for bursts. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Stanford Univ, Ctr Space Sci & Astrophys, Stanford, CA 94305 USA. Stanford Univ, Astron Program, Stanford, CA 94305 USA. Stanford Univ, Dept Phys, Stanford, CA 94305 USA. RP Lee, A (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 31 TC 30 Z9 32 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD NOV PY 2000 VL 131 IS 1 BP 21 EP 38 DI 10.1086/317365 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 385ZY UT WOS:000166036100002 ER PT J AU Stanford, SA Stern, D van Breugel, W De Breuck, C AF Stanford, SA Stern, D van Breugel, W De Breuck, C TI The first sample of ultraluminous infrared galaxies at high redshift. I. Sample and near-infrared morphologies SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE galaxies : interactions; galaxies : starburst; infrared : galaxies; radio continuum : galaxies ID IRAS SOURCE FSC-10214+4724; STARBURST-AGN CONNECTION; STANDARD STARS; F15307+3252; LUMINOSITY; EMISSION; QUASAR; SYSTEM; NUCLEI; VLBI AB We present a new sample of distant ultraluminous infrared galaxies. The sample was selected from a positional cross-correlation of the IRAS Faint Source Catalog with the FIRST database. Objects from this set were selected for spectroscopy by virtue of following the well-known star-forming galaxy correlation between 1.4 GHz and 60 mum flux, and by being optically faint on the POSS. Optical identification and spectroscopy were obtained for 108 targets at the Lick Observatory 3 m telescope. Most objects show spectra typical of starburst galaxies and do not show the high-ionization lines of active galactic nuclei. The redshift distribution covers 0.1 < z < 0.9, with 13 objects at z > 0.5 and an average redshift of (z) over bar = 0.31. K-band images were obtained at the IRTF, Lick, and Reck observatories in sub-arcsec seeing of all optically identified targets. About two-thirds of the objects appear to be interacting galaxies, while the other one-third appear to be normal. Nearly all the identified objects have far-IR luminosities greater than 10(11) L., and similar to 25% have L-FIR > 10(12) L.. C1 Univ Calif Davis, Dept Phys, Livermore, CA 94550 USA. Univ Calif Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Univ Calif Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. Univ Calif Lawrence Livermore Natl Lab, Leiden Observ, Livermore, CA 94550 USA. Univ Calif Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. RP Stanford, SA (reprint author), Univ Calif Davis, Dept Phys, Livermore, CA 94550 USA. NR 34 TC 55 Z9 55 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD NOV PY 2000 VL 131 IS 1 BP 185 EP 221 DI 10.1086/317369 PG 37 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 385ZY UT WOS:000166036100007 ER PT J AU Nahar, SN Pradhan, AK Zhang, HL AF Nahar, SN Pradhan, AK Zhang, HL TI Electron-ion recombination rate coefficients and photoionization cross sections for astrophysically abundant elements. IV. Relativistic calculations for CIV and CV for ultraviolet and X-ray modeling SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE atomic data; atomic processes; line : formation; X-rays : general ID HELIUM-LIKE IONS; DIELECTRONIC RECOMBINATION; ATOMIC DATA; OSCILLATOR-STRENGTHS; IONIZATION FRACTIONS; OPACITY CALCULATIONS; IRON PROJECT; SPECTRA; CARBON; TEMPERATURE AB The first complete set of unified cross sections and rate coefficients are calculated for photoionization and recombination of He- and Li-like ions using the relativistic Breit-Pauli R-matrix method. We present total, unified (e + ion) recombination rate coefficients for (e + C VI --> C v) and (e + C V --> C IV), including fine structure. Level-specific recombination rate coefficients up to the n = 10 levels are also obtained for the first time; these differ considerably from the approximate rates currently available. Applications to recombination-cascade coefficients in X-ray spectral models of Ka emission from the important He-like ions are pointed out. The overall uncertainty in the total recombination rates should not exceed 10%-20%. Ionization fractions for carbon are recomputed in the coronal approximation using the new rates. The present (e + ion) recombination rate coefficients are compared with several sets of available data, including previous LS coupling results and "'experimentally derived" rate coefficients. The roles of relativistic fine structure, resolution of resonances, radiation damping, and interference effects are discussed. Two general features of recombination rates are noted: (1) the nonresonant (radiative recombination) peak as E, T --> 0, and (2) the high-rr resonant (dielectronic recombination) peak. C1 Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Los Alamos, NM 87545 USA. RP Nahar, SN (reprint author), Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. NR 42 TC 28 Z9 28 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD NOV PY 2000 VL 131 IS 1 BP 375 EP 389 DI 10.1086/317366 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 385ZY UT WOS:000166036100013 ER PT J AU Voelz, NJ McArthur, JV AF Voelz, NJ McArthur, JV TI An exploration of factors influencing lotic insect species richness SO BIODIVERSITY AND CONSERVATION LA English DT Review DE aquatic insects; biodiversity; blackwater stream; habitat diversity; productivity; species richness ID SNAG-DWELLING MAYFLIES; AQUATIC INSECTS; SOUTH-CAROLINA; BLACKWATER RIVER; DIVERSITY; STREAM; CREEK; BIODIVERSITY; PATTERNS; ECOSYSTEM AB An understanding of factors that influence species richness of lotic insects is generally lacking. We present comparative data on aquatic insect species richness from several North American and other streams. Factors such as large sample numbers and drainage area (species area relationships) are not significant predictors of species richness across the streams we examined. We explore several hypotheses regarding the origins and maintenance of species richness using Upper Three Runs Creek (UTR), South Carolina, USA, as a reference stream. UTR has the highest species richness of any stream in the Western Hemisphere. Hypotheses examined included historical, regional and local processes such as: (1) Evolutionary time, (2) disturbance regime/environmental variability, (3) temperature/evolutionary-speed, (4) productivity, and (5) habitat heterogeneity. Of these hypotheses, we suggest that productivity and habitat heterogeneity appear to contribute most to the high species richness found in UTR. We believe that multidisciplinary analysis of other streams is necessary because without this crucial information our knowledge of, and desire to protect biodiversity in streams will be wanting. C1 Univ Georgia, Savannah River Ecol Lab, Reprints Dept, Aiken, SC 29802 USA. St Cloud State Univ, Dept Biol Sci MS 262, St Cloud, MN 56301 USA. RP McArthur, JV (reprint author), Univ Georgia, Savannah River Ecol Lab, Reprints Dept, Drawer E, Aiken, SC 29802 USA. NR 114 TC 47 Z9 51 U1 4 U2 27 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0960-3115 J9 BIODIVERS CONSERV JI Biodivers. Conserv. PD NOV PY 2000 VL 9 IS 11 BP 1543 EP 1570 DI 10.1023/A:1008984802844 PG 28 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 372RQ UT WOS:000165248200004 ER PT J AU Cullum, BM Vo-Dinh, T AF Cullum, BM Vo-Dinh, T TI Optical nanosensors and biological measurements SO BIOFUTUR LA French DT Article ID SINGLE LIVING CELLS; CHEMICAL-ANALYSIS; PEBBLE SENSORS; DYE; PH; IMMOBILIZATION; BIOSENSOR; PROBES C1 Oak Ridge Natl Lab, Adv Monitoring Dev Grp, Oak Ridge, TN 37831 USA. RP Vo-Dinh, T (reprint author), Oak Ridge Natl Lab, Adv Monitoring Dev Grp, POB 2008, Oak Ridge, TN 37831 USA. NR 27 TC 1 Z9 1 U1 0 U2 1 PU EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER PI PARIS CEDEX 15 PA 23 RUE LINOIS, 75724 PARIS CEDEX 15, FRANCE SN 0294-3506 J9 BIOFUTUR JI Biofutur PD NOV PY 2000 VL 2000 IS 205 BP A1 EP A6 PG 6 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA 380TK UT WOS:000165719400005 ER PT J AU Mayor, C Brudno, M Schwartz, JR Poliakov, A Rubin, EM Frazer, KA Pachter, LS Dubchak, I AF Mayor, C Brudno, M Schwartz, JR Poliakov, A Rubin, EM Frazer, KA Pachter, LS Dubchak, I TI VISTA: visualizing global DNA sequence alignments of arbitrary length SO BIOINFORMATICS LA English DT Article AB VISTA is a program for visualizing global DNA sequence alignments of arbitrary length. It has a clean output, allowing for easy identification of similarity, and is easily configurable, enabling the visualization of alignments of various lengths at different levels of resolution. It is currently available on the web, thus allowing for easy access by all researchers. C1 Univ Calif Berkeley, Dept Math, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Natl Energy Res Sci Comp Ctr, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Genome Sci Dept, Berkeley, CA 94720 USA. RP Pachter, LS (reprint author), Univ Calif Berkeley, Dept Math, Berkeley, CA 94720 USA. FU NIGMS NIH HHS [GM-5748202] NR 9 TC 559 Z9 572 U1 0 U2 14 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 1367-4803 J9 BIOINFORMATICS JI Bioinformatics PD NOV PY 2000 VL 16 IS 11 BP 1046 EP 1047 DI 10.1093/bioinformatics/16.11.1046 PG 2 WC Biochemical Research Methods; Biotechnology & Applied Microbiology; Computer Science, Interdisciplinary Applications; Mathematical & Computational Biology; Statistics & Probability SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Computer Science; Mathematical & Computational Biology; Mathematics GA 391EY UT WOS:000166343700014 PM 11159318 ER PT J AU Vaknin, D Kelley, MS AF Vaknin, D Kelley, MS TI The structure of D-erythro-C18 ceramide at the air-water interface SO BIOPHYSICAL JOURNAL LA English DT Article ID X-RAY-DIFFRACTION; PHASE-TRANSITIONS; ACID MONOLAYERS; BREWSTER-ANGLE; REFLECTION; BEHAVIOR AB X-ray reflectivity (XR) and diffraction at grazing angles of incidence (GID) were conducted to determine the structure of synthetic D-erythro C18-ceramide films at the air-water interface at various surface pressures (pi). Analysis of the GID reveals that the monomolecular film, at the crystalline phase (pi > 0 mN/m), is predominantly hexagonal. In this crystalline phase, the analysis of the reflectivity yields an electron density profile that consists of three distinct homogeneous slabs, one associated with the headgroup region and the other two with the hydrocarbon chains. At large molecular areas (pi approximate to 0), isolated crystalline domains coexist with two-dimensional gas phase. Within the crystalline domains, we find an orthorhombic arrangement of the chains that coexists with the hexagonal symmetry. It is argued that the two-dimensional orthorhombic crystals are induced by hydrogen bonding between headgroups even at very low surface pressures. Although their structure is incommensurate with the simple hexagonal arrangement, they act as nucleation centers for the conventional hexagonal phase which dominates at high pi. C1 Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Vaknin, D (reprint author), Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RI Vaknin, David/B-3302-2009; OI Vaknin, David/0000-0002-0899-9248; Kelley, Michael/0000-0002-6702-7676 NR 25 TC 40 Z9 40 U1 0 U2 1 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD NOV PY 2000 VL 79 IS 5 BP 2616 EP 2623 PG 8 WC Biophysics SC Biophysics GA 370CE UT WOS:000165104500032 PM 11053134 ER PT J AU Krishnan, MS Taylor, F Davison, BH Nghiem, NP AF Krishnan, MS Taylor, F Davison, BH Nghiem, NP TI Economic analysis of fuel ethanol production from corn starch using fluidized-bed bioreactors SO BIORESOURCE TECHNOLOGY LA English DT Article DE fuel ethanol; fluidized-bed bioreactors; immobilization; economic analysis ID ZYMOMONAS-MOBILIS AB The economics of fuel ethanol production from dry-milled corn starch were studied in fluidized-bed bioreactors (FBRs) using immobilized biocatalysts. Glucoamylase immobilized on porous diatomaceous earth was used for hydrolysis of the starch to glucose in a packed-bed reactor. The fermentation of glucose to ethanol was carried out in FBRs using Zymomonas mobilis immobilized in kappa-carageenan beads. Volumetric ethanol productivities of up to 24 g/l h were achieved in non-optimized laboratory-scale systems. For a 15 million gal/yr ethanol plant, an economic analysis of this process was performed with Aspen Plus (Aspen Technology, Cambridge, MA) process simulation software. The analysis shows that an operating cost savings in the range of 1.1-3.1 cents/gal can be realized by using the FBR technology. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. USDA, Eastern Reg Res Ctr, Wyndmoor, PA 19038 USA. RP Nghiem, NP (reprint author), Oak Ridge Natl Lab, Div Chem Technol, POB 2008, Oak Ridge, TN 37831 USA. RI Davison, Brian/D-7617-2013 OI Davison, Brian/0000-0002-7408-3609 NR 12 TC 41 Z9 44 U1 0 U2 5 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0960-8524 J9 BIORESOURCE TECHNOL JI Bioresour. Technol. PD NOV PY 2000 VL 75 IS 2 BP 99 EP 105 DI 10.1016/S0960-8524(00)00047-X PG 7 WC Agricultural Engineering; Biotechnology & Applied Microbiology; Energy & Fuels SC Agriculture; Biotechnology & Applied Microbiology; Energy & Fuels GA 328NV UT WOS:000087857700001 ER PT J AU Williams, J McGrath, WJ Mangel, WF AF Williams, J McGrath, WJ Mangel, WF TI Sensitive method to identify and characterize proteinases in situ after SDS-PAGE SO BIOTECHNIQUES LA English DT Article ID HUMAN ADENOVIRUS PROTEINASE; ELECTROPHORETIC ANALYSIS; POLYACRYLAMIDE GELS; SERINE PROTEINASES; PROTEASES; CASEIN; FLUORESCENCE; PLASMINOGEN; INHIBITORS; RHODAMINE AB Cells and body fluids contain numerous, different proteinases; to identify and characterize them are both important and dial cult tasks. Especially difficult to identify and characterize are highly specific proteinases. Here, we present an extremely sensitive and quantitative method to characterize proteinases fractionated by SDS-PAGE that cleave specific rhodamine-based fluorogenic substrates. To rest the sensitivity of the technique, we used trypsin as our model system. Filter paper impregnated with rhodamine-based fluorogenic substrates was placed on a gel, and bands of fluorescence originating from specific proteinases,were visualized in real lime. The method is very sensitive; picogram amounts of trypsin can be detected. The method should be very general, in that even proteinases whose substrates require amino acids C-terminal to the cleavage site may be identified and characterized. The results allow one to obtain not only information on the substrate specificity of a specific enzyme but also information about its molecular weight. C1 Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Mangel, WF (reprint author), Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. FU NIAID NIH HHS [AI41599] NR 20 TC 4 Z9 4 U1 0 U2 0 PU EATON PUBLISHING CO PI NATICK PA 154 E. CENTRAL ST, NATICK, MA 01760 USA SN 0736-6205 J9 BIOTECHNIQUES JI Biotechniques PD NOV PY 2000 VL 29 IS 5 BP 1108 EP 1113 PG 6 WC Biochemical Research Methods; Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 373EF UT WOS:000165274900025 PM 11084874 ER PT J AU Kadam, KL Wooley, RJ Aden, A Nguyen, QA Yancey, MA Ferraro, FM AF Kadam, KL Wooley, RJ Aden, A Nguyen, QA Yancey, MA Ferraro, FM TI Softwood forest thinnings as a biomass source for ethanol production: A feasibility study for California SO BIOTECHNOLOGY PROGRESS LA English DT Article ID SULFUR-DIOXIDE ADDITION; STEAM EXPLOSION; PINUS-RADIATA AB A plan has been put forth to strategically thin northern California forests to reduce fire danger and improve forest health. The resulting biomass residue, instead of being open burned, can be converted into ethanol that can be used as a fuel oxygenate or an octane enhancer. Economic potential for a biomass-to-ethanol facility using this softwood biomass was evaluated for two cases: stand-alone and co-located. The colocated case refers to a specific site with an existing biomass power facility near Martell, California. A two-stage dilute acid hydrolysis process is used for the production of ethanol from softwoods, and the residual lignin is used to generate steam and electricity. For a plant processing 800 dry tonnes per day of feedstock, the co-located case is an economically attractive concept. Total estimated capital investment is approximately $70 million for the co-located plant, and the resulting internal rate of return (IRR) is about 24% using 25% equity financing. A sensitivity analysis showed that ethanol selling price and fixed capital investment have a substantial effect on the IRR. It can be concluded that such a biomass-to-ethanol plant seems to be an appealing proposition for California, if ethanol replaces methyl tert-butyl ether, which is slated for a phaseout. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. Merrick & Co, Aurora, CO 80014 USA. RP Kadam, KL (reprint author), Natl Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80401 USA. NR 27 TC 30 Z9 36 U1 0 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 8756-7938 J9 BIOTECHNOL PROGR JI Biotechnol. Prog. PD NOV-DEC PY 2000 VL 16 IS 6 BP 947 EP 957 DI 10.1021/bp000127s PG 11 WC Biotechnology & Applied Microbiology; Food Science & Technology SC Biotechnology & Applied Microbiology; Food Science & Technology GA 380TF UT WOS:000165719000005 PM 11101320 ER PT J AU Press, OW Eary, JF Gooley, T Gopal, AK Liu, S Rajendran, JG Maloney, DG Petersdorf, S Bush, SA Durack, LD Martin, PJ Fisher, DR Wood, B Borrow, JW Porter, B Smith, JP Matthews, DC Appelbaum, FR Bernstein, ID AF Press, OW Eary, JF Gooley, T Gopal, AK Liu, S Rajendran, JG Maloney, DG Petersdorf, S Bush, SA Durack, LD Martin, PJ Fisher, DR Wood, B Borrow, JW Porter, B Smith, JP Matthews, DC Appelbaum, FR Bernstein, ID TI A phase I/II trial of iodine-131-tositumomab (anti-CD20), etoposide, cyclophosphamide, and autologous stem cell transplantation for relapsed B-cell lymphomas SO BLOOD LA English DT Article ID NON-HODGKINS-LYMPHOMA; BONE-MARROW TRANSPLANTATION; POLYMERASE CHAIN-REACTION; RADIOLABELED MONOCLONAL-ANTIBODIES; I-131 LYM-1 ANTIBODY; MYELODYSPLASTIC SYNDROME; FRACTIONATED RADIOIMMUNOTHERAPY; LATE COMPLICATION; FOLLOW-UP; DOSIMETRY AB Relapsed B-cell lymphomas are incurable with conventional chemotherapy and radiation therapy, although a fraction of patients can be cured with high-dose chemoradiotherapy and autologous stem-cell transplantation (ASCT), We conducted a phase I/II trial to estimate the maximum tolerated dose (MTD) of iodine 131 (I-131)-tositumomab (anti-CD20 antibody) that could be combined with etoposide and cyclophosphamide followed by ASCT in patients with relapsed B-cell lymphomas. Fifty-two patients received a trace-labeled infusion of 1.7 mg/kg I-131-tositumomab (185-370 MBq) followed by serial quantitative gamma-camera imaging and estimation of absorbed doses of radiation to tumor sites and normal organs. Ten days later, patients received a therapeutic infusion of 1.7 mg/kg tositumomab labeled with an amount of I-131 calculated to deliver the target dose of radiation (20-27 Gy) to critical normal organs (liver, kidneys, and lungs). Patients were maintained in radiation isolation until their total-body radioactivity was less than 0.07 mSv/h at 1 m, They were then given etoposide and cyclophosphamide followed by ASCT. The MTD of I-131-tositumomab that could be safely combined with 60 mg/kg etoposide and 100 mg/kg cyclophosphamide delivered 25 Gy to critical normal organs. The estimated overall survival (OS) and progression-free survival (PFS) of all treated patients at 2 years was 83% and 68%, respectively. These findings compare favorably with those in a nonrandomized control group of patients who underwent transplantation, external-beam total-body irradiation, and etoposide and cyclophosphamide therapy during the same period (OS of 53% and PFS of 36% at 2 years), even after adjustment for confounding variables in a multivariable analysis. (C) 2000 by The American Society of Hematology. C1 Univ Washington, Ctr Canc, Dept Med, Seattle, WA 98195 USA. Univ Washington, Dept Pathol, Seattle, WA 98195 USA. Univ Washington, Dept Pediat, Seattle, WA 98195 USA. Univ Washington, Dept Radiol, Seattle, WA 98195 USA. Univ Washington, Dept Biol Struct, Seattle, WA 98195 USA. Univ Washington, Dept Biostat, Seattle, WA 98195 USA. Fred Hutchinson Canc Res Ctr, Seattle, WA 98104 USA. First Hill Diagnost Imaging, Richland, WA USA. Pacific NW Natl Lab, Richland, WA 99352 USA. RP Press, OW (reprint author), Univ Washington, Ctr Canc, Dept Med, Box 356043, Seattle, WA 98195 USA. FU NCI NIH HHS [P01CA44991] NR 38 TC 229 Z9 240 U1 1 U2 3 PU AMER SOC HEMATOLOGY PI WASHINGTON PA 1900 M STREET. NW SUITE 200, WASHINGTON, DC 20036 USA SN 0006-4971 J9 BLOOD JI Blood PD NOV 1 PY 2000 VL 96 IS 9 BP 2934 EP 2942 PG 9 WC Hematology SC Hematology GA 367RA UT WOS:000090074200003 PM 11049969 ER PT J AU Clark, EC Baxter, LR AF Clark, EC Baxter, LR TI Mammal-like striatal functions in Anolis I. Distribution of serotonin receptor subtypes, and absence of striosome and matrix organization SO BRAIN BEHAVIOR AND EVOLUTION LA English DT Article DE basal ganglia; serotonin receptors; acetylcholinesterase; naloxone; striosomes; Anolis ID OBSESSIVE-COMPULSIVE DISORDER; BASAL GANGLIA; COMPARTMENTAL ORGANIZATION; MESSENGER-RNA; RAT-BRAIN; NEUROTRANSMITTER ORGANIZATION; DISPLAY BEHAVIOR; GLOBUS-PALLIDUS; EVOLUTION; VERTEBRATES AB Serotonin (5-HT) 5-HT2A and 5-HT2C receptors are thought to play important roles in the mammalian striatum. As basal ganglia functions in general are thought highly conserved among amniotes, we decided to use in situ autoradiographic methods to determine the occurrence and distribution of pharmacologically mammal-like 5-HT2A and 5-HT2C receptors in the lizard, Anolis carolinensis, with particular attention to the striatum, We also determined the distributions of 5-HT1A, 5-HT1B/D, 5-HT3, and 5-HTuptake receptors for comparison. All 5-HT receptors examined showed pharmacological binding specificity, and forebrain binding density distributions that resembled those reported for mammals. Anolis 5-HT2A/C and 5-HT1A site distributions were similar in both in vivo and ex vivo binding experiments. 5-HT2A&C receptors occur in both high and low affinity states, the former having preferential affinity for I-125-(+/-)-2,5-dimethoxy-4-iodo-amphetamine hydrochloride (I-125-DOI). In mammals I-125-DOI binding shows a patchy density distribution in the striatum, being more dense in striosomes than in surrounding matrix. There was no evidence of any such patchy density of I-125-DOI binding in the anole striatum, however. As a further indication that anoles do not possess a striosome and matrix striatal organization, neither H-3-naloxone binding nor histochemical staining for acetylcholinesterase activity (AChE) were patchy. AChE did show a band-like striatal distribution, however, similar to that seen in birds. Copyright (C) 2001 S. Karger AG, Basel. C1 Univ Calif Los Angeles, Crump Inst Biomed Imaging, Los Angeles, CA USA. Univ Calif Los Angeles, DoE, Lab Struct Biol & Mol Med, Nucl Med Lab,Dept Psychiat, Los Angeles, CA USA. Univ Calif Los Angeles, DoE, Lab Struct Biol & Mol Med, Nucl Med Lab,Dept Pharmacol, Los Angeles, CA USA. Univ Alabama, Dept Neurobiol, Birmingham, AL USA. Univ Alabama, Dept Psychol, Birmingham, AL USA. Univ Alabama, Dept Psychiat & Behav Neurobiol, Birmingham, AL USA. RP Baxter, LR (reprint author), Sparks Res Ctr 1001, 1720 7th Ave S, Birmingham, AL 35294 USA. NR 84 TC 13 Z9 13 U1 0 U2 0 PU KARGER PI BASEL PA ALLSCHWILERSTRASSE 10, CH-4009 BASEL, SWITZERLAND SN 0006-8977 J9 BRAIN BEHAV EVOLUT JI Brain Behav. Evol. PD NOV PY 2000 VL 56 IS 5 BP 235 EP 248 DI 10.1159/000047207 PG 14 WC Behavioral Sciences; Neurosciences; Zoology SC Behavioral Sciences; Neurosciences & Neurology; Zoology GA 406YW UT WOS:000167244600001 PM 11251316 ER PT J AU Clark, EC Baxter, LR Dure, LS Ackermann, RF Kemp, GF Bachus, SE AF Clark, EC Baxter, LR Dure, LS Ackermann, RF Kemp, GF Bachus, SE TI Mammal-like striatal functions in Anolis II. Distribution of dopamine D-1 and D-2 receptors, and a laminar pattern of basal ganglia sub-systems SO BRAIN BEHAVIOR AND EVOLUTION LA English DT Article DE basal ganglia; dopamine; enkephalin; Anolis ID OBSESSIVE-COMPULSIVE DISORDER; SUBTHALAMIC NUCLEUS; MESSENGER-RNA; RAT STRIATUM; D2 DOPAMINE; ACETYLCHOLINE-RELEASE; GLOBUS-PALLIDUS; SPINY NEURONS; SUBSTANCE-P; BRAIN AB We used in situ autoradiographic ligand binding methods to determine the occurrence and distribution of dopamine D-1 and D-2 receptor sub-types in the anole lizard, Anolis carolinensis, Both were present and exhibited pharmacological specificity characteristics similar to those described for mammals. However, unlike in mammals where in the neostriatum [outside the nucleus accumbens/olfactory tubercle complex (NA/OT)] these receptors exhibit only slight dorsolateral (D-2 high, D-1 low) to ventromedial (D-1 high, D-2 low) gradients that co-mingle extensively, in the anole striatum outside the NA/OT there was a striking laminar pattern, with little if any overlap between D-2 (high in a dorsal band) and D-1 thigh ventral to the D-2 band) distributions. As D-1 receptors are related to the direct and D-2 to the indirect basal ganglia (BG) subsystems in mammals, we also determined anole striatal distributions of pre-proenkephalin mRNA, a marker for striatal efferents to the indirect BG subsystem in mammals, Here, too, there was a striking laminar pattern, with pre-proenkephalin mRNA in a band similar to that seen for Dg receptors. The crisp neuroanatomical separation between these classic BG subsystem markers in Anolis striatum make this species attractive for the study of such systems' functions during behavior. Copyright (C) 2001 S. Karger AG, Basel. C1 NIMH, Clin Brain Disorders Branch, Bethesda, MD 20892 USA. Univ Calif Los Angeles, Sch Med, Crump Inst Biomed Imaging, Los Angeles, CA USA. Univ Calif Los Angeles, Sch Med, DoE,Dept Psychiat, Lab Struct Biol & Mol Med,Lab Nucl Med, Los Angeles, CA USA. Univ Calif Los Angeles, Sch Med, DoE,Dept Pharmacol, Lab Struct Biol & Mol Med,Lab Nucl Med, Los Angeles, CA USA. Univ Alabama, Dept Neurol, Birmingham, AL 35294 USA. Univ Alabama, Dept Pediat, Birmingham, AL 35294 USA. Univ Alabama, Dept Neurobiol, Birmingham, AL 35294 USA. Univ Alabama, Dept Psychol, Birmingham, AL 35294 USA. Univ Alabama, Dept Psychiat & Behav Neurobiol, Birmingham, AL 35294 USA. RP Baxter, LR (reprint author), Sparks Res Ctr 1001, 1720 7th Ave, Birmingham, AL 35294 USA. RI Dure, Leon/B-3243-2008 NR 52 TC 13 Z9 13 U1 0 U2 0 PU KARGER PI BASEL PA ALLSCHWILERSTRASSE 10, CH-4009 BASEL, SWITZERLAND SN 0006-8977 J9 BRAIN BEHAV EVOLUT JI Brain Behav. Evol. PD NOV PY 2000 VL 56 IS 5 BP 249 EP 258 DI 10.1159/000047208 PG 10 WC Behavioral Sciences; Neurosciences; Zoology SC Behavioral Sciences; Neurosciences & Neurology; Zoology GA 406YW UT WOS:000167244600002 PM 11251317 ER PT J AU Peppler, RA Bahrmann, CP Barnard, JC Campbell, JR Cheng, MD Ferrare, RA Halthore, RN Heilman, LA Hlavka, DL Laulainen, NS Lin, CJ Ogren, JA Poellot, MR Remer, LA Sassen, K Spinhirne, JD Splitt, ME Turner, DD AF Peppler, RA Bahrmann, CP Barnard, JC Campbell, JR Cheng, MD Ferrare, RA Halthore, RN Heilman, LA Hlavka, DL Laulainen, NS Lin, CJ Ogren, JA Poellot, MR Remer, LA Sassen, K Spinhirne, JD Splitt, ME Turner, DD TI ARM Southern Great Plains site observations of the smoke pall associated with the 1998 Central American fires SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID RAMAN LIDAR MEASUREMENTS; OPTICAL-PROPERTIES; WATER-VAPOR; SIZE DISTRIBUTION; ATMOSPHERIC RADIATION; AEROSOL EXTINCTION; MICROPULSE LIDAR; FLOW PATTERNS; TRAJECTORIES; BRAZIL AB Drought-stricken areas of Central America and Mexico were victimized in 1998 by forest and brush fires that burned out of control during much of the first half of the year. Wind currents at various times during the episode helped transport smoke from these fires over the Gulf of Mexico and into portions of the United Slates. Visibilities were greatly reduced during favorable flow periods from New Mexico to south Florida and northward to Wisconsin as a result of this smoke and haze. In response to the reduced visibilities and increased pollutants, public health advisories and information statements were issued by various agencies in Gulf Coast states and in Oklahoma. This event was also detected by a unique array of instrumentation deployed at the U.S. Department of Energy's Atmospheric Radiation Measurement (ARM) program Southern Great Plains Cloud and Radiation Testbed and by sensors of the Oklahoma Department of Environmental Quality/Air Quality Division. Observations from these measurement devices suggest elevated levels of aerosol loading and ozone concentrations during May 1998 when prevailing winds were favorable for the transport of the Central American smoke pall into Oklahoma and Kansas. In particular, aerosol extinction profiles derived from the ARM Raman lidar measurements revealed large variations in the vertical distribution of the smoke. C1 Cooperat Inst Mesoscale Meteorol Studies, Norman, OK 73019 USA. Pacific NW Natl Lab, Richland, WA USA. Sci Syst & Applicat Inc, Lanham, MD USA. Oak Ridge Natl Lab, Oak Ridge, TN USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. NASA, Langley Res Ctr, Sci Applicat Int Corp, Hampton, VA 23665 USA. Oak Ridge Associated Univ, Oak Ridge, TN USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Univ N Dakota, Grand Forks, ND 58201 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Utah, Salt Lake City, UT USA. Univ Utah, Cooperat Inst Reg Predict, Salt Lake City, UT USA. RP Peppler, RA (reprint author), Cooperat Inst Mesoscale Meteorol Studies, 100 E Boyd St,Room 1110, Norman, OK 73019 USA. RI Campbell, James/C-4884-2012; Cheng, Meng-Dawn/C-1098-2012; Xiongfei, Zhao/G-7690-2015; Ogren, John/M-8255-2015; Lin, Che-Jen/K-1808-2013; OI Campbell, James/0000-0003-0251-4550; Ogren, John/0000-0002-7895-9583; Lin, Che-Jen/0000-0001-5990-3093; Splitt, Michael/0000-0002-7690-5100 NR 52 TC 51 Z9 52 U1 2 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD NOV PY 2000 VL 81 IS 11 BP 2563 EP 2591 DI 10.1175/1520-0477(2000)081<2563:ASGPSO>2.3.CO;2 PG 29 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 370BB UT WOS:000165101300001 ER PT J AU Ivanova, IA Stephen, JR Chang, YJ Bruggemann, J Long, PE McKinley, JP Kowalchuk, GA White, DC Macnaughton, SJ AF Ivanova, IA Stephen, JR Chang, YJ Bruggemann, J Long, PE McKinley, JP Kowalchuk, GA White, DC Macnaughton, SJ TI A survey of 16S rRNA and amoA genes related to autotrophic ammonia-oxidizing bacteria of the beta-subdivision of the class proteobacteria in contaminated groundwater SO CANADIAN JOURNAL OF MICROBIOLOGY LA English DT Article DE Nitrosomonas; Nitrosospira; nitrification; groundwater; amoA; 16S ID GRADIENT GEL-ELECTROPHORESIS; RIBOSOMAL-RNA GENES; NITROSOSPIRA SP; NITROSOMONAS-EUROPAEA; MOLECULAR ANALYSIS; MONOOXYGENASE; SEQUENCES; SOIL; POPULATIONS; DIVERSITY AB In this study, we investigated the size and structure of autotrophic ammonia oxidizer (AAO) communities in the groundwater of a contamination plume originating from a mill-tailings disposal site. The site has high levels of dissolved N from anthropogenic sources, and exhibited wide variations in the concentrations of NO3- and NH3 + NH4+. Community structures were examined by PCR-DGGE targeting 16S rDNA with band excision and sequence analysis, and by analysis of amoA fragment clone libraries. AAO population sizes were estimated by competitive PCR targeting the gene amoA, and correlated significantly with nitrate concentration. Most samples revealed novel diversity in AAO 16S rDNA and amoA gene sequences. Both 16S rDNA and amoA analyses suggested that all samples were dominated by Nitrosomonas sp., Nitrosospira sp. being detected in only 3 of 15 samples. This study indicated numerical dominance of Nitrosomonas over Nitrosospira in groundwater, and suggests that groundwater ammonia oxidizers are more similar to those dominating freshwater sediments than bulk soil. C1 Univ Tennessee, Ctr Environm Biotechnol, Knoxville, TN 37923 USA. Univ Sofia, Fac Biol, Dept Microbiol, BU-1126 Sofia, Bulgaria. Pacific NW Natl Lab, Appl Geol & Geochem Grp, Richland, WA 99352 USA. Pacific NW Natl Lab, Interfacial Geochem Grp, Richland, WA 99352 USA. Netherlands Inst Ecol, Ctr Terr Ecol, NL-6666 ZG Heteren, Netherlands. Oak Ridge Natl Lab, Div Biol Sci, Oak Ridge, TN 37831 USA. RP Macnaughton, SJ (reprint author), AEA Technol Environm, Abingdon OX14 3DB, Oxon, England. RI Kowalchuk, George/C-4298-2011; Long, Philip/F-5728-2013; OI Long, Philip/0000-0003-4152-5682; Ivanova, Iliana/0000-0001-5964-0609 NR 43 TC 40 Z9 43 U1 0 U2 12 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 NOV PY 2000 VL 46 IS 11 BP 1012 EP 1020 DI 10.1139/cjm-46-11-1012 PG 9 WC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Immunology; Microbiology SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Immunology; Microbiology GA 368TP UT WOS:000090133900006 PM 11109489 ER PT J AU Kulp, KS Knize, MG Malfatti, MA Salmon, CP Felton, JS AF Kulp, KS Knize, MG Malfatti, MA Salmon, CP Felton, JS TI Identification of urine metabolites of 2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine following consumption of a single cooked chicken meal in humans SO CARCINOGENESIS LA English DT Article ID MAMMARY EPITHELIAL-CELLS; HETEROCYCLIC AROMATIC-AMINES; N-ACETYLTRANSFERASE EXPRESSION; HUMAN LIVER-MICROSOMES; DNA ADDUCT LEVELS; FOOD MUTAGEN; WELL-DONE; COLORECTAL ADENOMAS; HEPATIC MICROSOMES; CYNOMOLGUS MONKEYS AB Many studies suggest that mutagenic/carcinogenic chemicals in the diet, like 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), may play a role in human cancer initiation. We have developed a method to quantify PhIP metabolites in human urine and have applied it to samples from female volunteers who had eaten a meal of cooked chicken. For this analysis, urine samples (5 mi) were spiked with a deuterium-labeled internal standard, adsorbed to a macroporous polymeric column and then eluted with methanol, lifter a solvent exchange to 0.01 M HCl, the urine extracts were passed through a filter, applied to a benzenesulfonic acid column, washed with methanol/acid and eluted with ammonium acetate and concentrated on a C-18 column. The metabolites were eluted from the C-18 column and quantified by LC/MS/MS. In our studies of human PhIP metabolism, eight volunteers were fed 200 g of cooked chicken containing a total of 27 mug PhIP, Urine samples were collected for 24 h after the meal, in 6 h aliquots, Although no metabolites could be found in urine collected from volunteers before eating the chicken, four major human PhIP metabolites, N-2-OH-PhIP-N3-glucuronide, PhIP-N-2-glucuronide 4'-PhIP-sulfate and N-2-OH-PhIP-N3-glucuronide, were found in the urine after the chicken meal, The volunteers in the study excreted 4-53% of the ingested PhIP dose in the urine. The rate of metabolite excretion varied among the subjects, however, in all of the subjects the majority of the metabolites were excreted in the first 12 h, Very little metabolite was detected in the urine after 18 h, In humans, N-2-OH-PhIP-N-2 glucuronide is the most abundant urinary metabolite, followed by PhIP-N-2-glucuronide, The variation seen in the total amount, excretion time and metabolite ratios with our method suggests that individual digestion, metabolism and/or other components of the diet may influence the absorption and amounts of metabolic products produced from PhIP. C1 Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94550 USA. RP Kulp, KS (reprint author), Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, L-452, Livermore, CA 94550 USA. FU NCI NIH HHS [CA5586] NR 65 TC 60 Z9 60 U1 2 U2 5 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0143-3334 J9 CARCINOGENESIS JI Carcinogenesis PD NOV PY 2000 VL 21 IS 11 BP 2065 EP 2072 DI 10.1093/carcin/21.11.2065 PG 8 WC Oncology SC Oncology GA 377ZF UT WOS:000165555800020 PM 11062169 ER PT J AU Goth-Goldstein, R Stampfer, MR Erdmann, CA Russell, M AF Goth-Goldstein, R Stampfer, MR Erdmann, CA Russell, M TI Interindividual variation in CYP1A1 expression in breast tissue and the role of genetic polymorphism SO CARCINOGENESIS LA English DT Article ID POLYMERASE CHAIN-REACTION; LUNG-CANCER; CYTOCHROME-P450IA1 GENE; SUSCEPTIBILITY; METABOLISM; RISK; IDENTIFICATION; ETIOLOGY; CELLS AB The cytochrome P4501A1 (CYP1A1) enzyme is regulated at the transcriptional level and its expression is influenced by genetic factors, polymorphisms in the structural and regulatory genes, and by environmental factors such as exposure to polycyclic aromatic hydrocarbons (PAHs), To investigate the role of CYP1A1 in breast cancer, we studied CYP1A1 expression in breast tissue, thereby taking all possible modifying factors into account. We measured CYP1A1 expression in 58 non-tumor breast tissue specimens from both breast cancer patients (n = 26) and cancer-free individuals (n = 32) using a newly developed reverse transcription-polymerase chain reaction assay. CYP1A1 expression varied between specimens similar to 400-fold and was independent of age. CYP1A1 expression was somewhat higher in tissue from breast cancer patients than in that from cancer-free individuals, but this difference was not statistically significant. Analysis for CYP1A1 genetic polymorphisms revealed eight variants, seven in the cancer-free group and one in the patient group. The variant genotype was not a good predictor of expression level. We conclude that high CYP1A1 expression could be a risk factor for breast cancer and that the known CYP1A1 polymorphisms are not good predictors of CYP1A1 expression. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Informat & Comp Sci Div, Berkeley, CA 94720 USA. RP Goth-Goldstein, R (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Environm Energy Technol Div, 1 Cyclotron Rd, Berkeley, CA 94720 USA. FU NCI NIH HHS [CA-24844] NR 26 TC 20 Z9 21 U1 0 U2 1 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0143-3334 J9 CARCINOGENESIS JI Carcinogenesis PD NOV PY 2000 VL 21 IS 11 BP 2119 EP 2122 DI 10.1093/carcin/21.11.2119 PG 4 WC Oncology SC Oncology GA 377ZF UT WOS:000165555800028 PM 11062177 ER PT J AU Ferer, MV Smith, DH AF Ferer, MV Smith, DH TI Filler cake removal efficiency: comparison of modeling results with experiment SO CHEMICAL ENGINEERING SCIENCE LA English DT Article DE filter cake; pulse cleaning; PFBC; powder tensile strength ID OPERATIONAL FILTRATION DATA; RIGID GAS FILTERS; ADHESIVE FAILURE; LAYER; FRACTURE; BEHAVIOR AB A fine-scale, quasi-static model has been used to study the cleaning of ceramic filters by a constant stress applied perpendicular to the layer of filter cake. The model includes randomly chosen bonding forces of adhesion between the substrate and imaginary 'gridblocks' within the layer, as well as cooperative forces of cohesion between adjacent 'gridblocks'. For small cohesive forces, the amount of cleaning varies continuously with the applied stress, a. From negligible cleaning at a minimum threshold value of the stress, the fraction of the layer removed, f(m)(sigma), increases to encompass the total layer, as the applied stress increases. This layer-removal function (cleaning efficiency) sharpens as the cooperative forces are increased, i.e. the slope of the cleaning efficiency, Deltaf(m)/Delta sigma increases, so that the extent of cleaning is more and more sensitive to changes in the applied stress. The fits to our results for the mid-point stress, sigma (1/2), of the cleaning efficiency, f(m)(sigma), and to the slope of the cleaning efficiency, chi = Deltaf(m)/Delta sigma, are used to collapse the modeling data to a single curve. We use these same parameters, sigma (1/2) and chi, to characterize existing experimental data for the cleaning efficiency (layer removal function) as a function of constant removal stress. These same parameters allow us to Ii) collapse the experimental data onto the aforementioned 'single' curve from the modeling and to (ii) estimate values of average adhesive and cohesive strengths for the experimental systems. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 W Virginia Univ, Dept Phys, Morgantown, WV 26506 USA. US DOE, Fed Energy Technol Ctr, Morgantown, WV 26507 USA. RP Ferer, MV (reprint author), W Virginia Univ, Dept Phys, POB 6315, Morgantown, WV 26506 USA. NR 32 TC 8 Z9 8 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0009-2509 J9 CHEM ENG SCI JI Chem. Eng. Sci. PD NOV PY 2000 VL 55 IS 21 BP 5003 EP 5011 DI 10.1016/S0009-2509(00)00103-2 PG 9 WC Engineering, Chemical SC Engineering GA 367XN UT WOS:000090087300017 ER PT J AU Wood, BD Quintard, M Whitaker, S AF Wood, BD Quintard, M Whitaker, S TI Jump conditions at non-uniform boundaries: the catalytic surface SO CHEMICAL ENGINEERING SCIENCE LA English DT Article DE jump condition; non-uniform boundary; catalytic surface; spatial averaging; effective reaction rate; closure problem ID CONTROLLED LIGAND-BINDING; RECEPTOR INTERACTIONS; POROUS-MEDIA; DIFFUSION; KINETICS; ISLANDS; ARCHIPELAGOS; OXIDATION; ARRAYS AB A spatially smoothed jump condition is developed for the process of diffusion and reaction at a catalytic surface where a first-order, irreversible reaction takes place at isolated regions on the fluid-solid interface. The point jump condition for this process is given by -n(gamma kappa).D gamma delc(A gamma) = kc(A gamma) at the gamma-kappa interface, in which the rate coefficient k undergoes abrupt changes with position on the fluid-solid interface. The averaging procedure leads to a spatially smoothed jump condition that takes the form -n(gamma kappa).D(gamma)del [c(A gamma)](gamma) = k(eff)[c(A gamma)](gamma) at the gamma-kappa interface, in which the effective reaction rate coefficient is determined by the solution of a closure problem. It is this effective reaction rate coefficient, times the interfacial area per unit volume, that is measured in a typical experimental study of diffusion and reaction in a porous catalyst. The solution of the closure problem allows one to relate the intrinsic properties of the catalytic surface to k(eff), and the results are presented in terms of a surface effectiveness factor as a function of a Thiele modulus. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Davis, Dept Chem Engn & Mat Sci, Davis, CA 95616 USA. Pacific NW Natl Lab, Richland, WA 99352 USA. Inst Mecan Fluides Toulouse, F-31400 Toulouse, France. RP Whitaker, S (reprint author), Univ Calif Davis, Dept Chem Engn & Mat Sci, Davis, CA 95616 USA. RI Wood, Brian/K-4025-2012; Wood, Brian/J-8362-2013; OI Wood, Brian/0000-0003-3152-7852; Wood, Brian/0000-0003-3152-7852; Quintard, Michel/0000-0002-6150-7011 NR 32 TC 25 Z9 25 U1 2 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0009-2509 J9 CHEM ENG SCI JI Chem. Eng. Sci. PD NOV PY 2000 VL 55 IS 22 BP 5231 EP 5245 DI 10.1016/S0009-2509(00)00161-5 PG 15 WC Engineering, Chemical SC Engineering GA 373YZ UT WOS:000165318800002 ER PT J AU Braun, A Bartsch, M Schnyder, B Kotz, R AF Braun, A Bartsch, M Schnyder, B Kotz, R TI A model for the film growth in samples with two moving reaction frontiers - an application and extension of the unreacted-core model SO CHEMICAL ENGINEERING SCIENCE LA English DT Article DE film growth; Lambert W function; unreacted core shrinking; carbon activation; exactly solvable growth model AB A mathematical expression for the film thickness in a flat sample, reacting with a fluid, as a function of reaction time is derived. The formulation is based on a gas-solid reaction similar to the unreacted core shrinking model and takes into account two moving reaction frontiers, one due to the shrinking unreacted core, and one due to the changing thickness of the samples as a result of combustion. The equation of motion for the two reaction boundaries is solved exactly for flat samples applying a Lambert W function. The model for the flat samples is compared with experimental results. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Paul Scherrer Inst, Gen Energy Res Dept, CH-5232 Villigen, Switzerland. RP Braun, A (reprint author), Lawrence berkeley Natl Lab, MS 70-108 B,1 Cyclotron Rd, Berkeley, CA 94720 USA. RI BRAUN, Artur/A-1154-2009 OI BRAUN, Artur/0000-0002-6992-7774 NR 21 TC 12 Z9 13 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0009-2509 J9 CHEM ENG SCI JI Chem. Eng. Sci. PD NOV PY 2000 VL 55 IS 22 BP 5273 EP 5282 DI 10.1016/S0009-2509(00)00143-3 PG 10 WC Engineering, Chemical SC Engineering GA 373YZ UT WOS:000165318800005 ER PT J AU Grate, JW Kaganove, SN Nelson, DA AF Grate, JW Kaganove, SN Nelson, DA TI Carbosiloxane polymers for chemical sensors SO CHEMICAL INNOVATION LA English DT Article ID ACOUSTIC-WAVE; SORBENT COATINGS; POLYMERIZATION; HYDROSILATION; ORGANOPHOSPHORUS; SORPTION; DESIGN; ARRAYS C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Michigan Mol Inst, Midland, MI 48640 USA. RP Grate, JW (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. NR 25 TC 19 Z9 19 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1527-4799 J9 CHEM INNOV JI Chem. Innov. PD NOV PY 2000 VL 30 IS 11 BP 29 EP 37 PG 9 WC Chemistry, Applied SC Chemistry GA 371ZR UT WOS:000165209600005 ER PT J AU Henson, NJ Eckert, J Hay, PJ Redondo, A AF Henson, NJ Eckert, J Hay, PJ Redondo, A TI Adsorption of ethane and ethene in Na-Y studied by inelastic neutron scattering and computation SO CHEMICAL PHYSICS LA English DT Article ID ETHYLENE SORPTION COMPLEX; ABINITIO CALCULATIONS; CARBON-DIOXIDE; ZEOLITE-X; DENSITY; MOLECULES; METHANE; GAS; APPROXIMATION; SPECTROMETER AB Inelastic neutron scattering (INS) spectra were collected for ethane and ethene in Na zeolite-Y (Si/Al = 2.0). The INS spectrum of ethane in Na-Y consists of a single broad adsorption band in which no individual peaks can be discerned. Monte-Carlo docking calculations predicted a large number of similar binding sites with energies ranging from 24 to 37 kJ mol(-1) in the region of the four rings on the wall of the faujasite supercage. This is consistent with the broad feature observed in the INS spectrum. In contrast, the MS spectrum of ethene in Na-Y shows significant fine structure, and several peaks can be distinguished in the region < 1000 cm(-1). Monte-Carlo docking calculations with a molecular mechanics type force field were performed and predict two binding sites, one bound to the SII cation site (binding energy = 36.2 kJ mol(-1)) and one lying in the window site (binding energy = 19.4 kJ mol(-1)). Quantum mechanical calculations were also performed using a cluster model for the SII binding site but resulted in a significantly lower binding energy, even when correlation corrections were employed (18,2 kJ mol(-1)). Vibrational spectra were calculated using both quantum mechanical and molecular mechanics based techniques and the results compared with the MS spectra. A significantly better fit was obtained using the latter method and the peaks could be assigned based on the computed eigenvectors. Analogies are drawn between the assignments and other previous studies of Zeise's salt and related compounds. (C) 2000 Published by Elsevier Science B.V. C1 Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Los Alamos Natl Lab, Manuel Lujan Jr Neutron Scattering Ctr, Los Alamos, NM 87545 USA. RP Henson, NJ (reprint author), Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. EM neil.henson@lanl.gov NR 47 TC 9 Z9 9 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0104 J9 CHEM PHYS JI Chem. Phys. PD NOV 1 PY 2000 VL 261 IS 1-2 SI SI BP 111 EP 124 DI 10.1016/S0301-0104(00)00239-1 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 368MT UT WOS:000090121700009 ER PT J AU Gailer, J George, GN Pickering, IJ Madden, S Prince, RC Yu, EY Denton, MB Younis, HS Aposhian, HV AF Gailer, J George, GN Pickering, IJ Madden, S Prince, RC Yu, EY Denton, MB Younis, HS Aposhian, HV TI Structural basis of the antagonism between inorganic mercury and selenium in mammals SO CHEMICAL RESEARCH IN TOXICOLOGY LA English DT Article ID HG-SE COMPLEX; RAY-ABSORPTION SPECTROSCOPY; NUCLEAR-MAGNETIC-RESONANCE; SELENOPROTEIN-P; URINARY MERCURY; SODIUM SELENITE; PLASMA-PROTEIN; BINDING; BLOOD; CADMIUM AB Mercuric chloride toxicity in mammals can be overcome by co-administration of sodium selenite. We report a study of the mutual detoxification product in rabbit plasma, and of a Hg-Se-S-containing species synthesized by addition of equimolar mercuric chloride and sodium selenite to aqueous, buffered glutathione. Chromatographic purification of this Hg-Se-S species and subsequent structural analysis by Se and Hg extended X-ray absorption fine structure (EXAFS) spectroscopy revealed the presence of four-coordinate Se and Hg entities separated by 2.61 Angstrom. Hg and Se near-edge X-ray absorption spectroscopy of erythrocytes, plasma, and bile of rabbits that had been injected with solutions of sodium selenite and mercuric chloride showed that Hg and Se in plasma samples exhibited X-ray absorption spectra that were essentially identical to those of the synthetic Hg-Se-S species. Thus, the molecular detoxification product of sodium selenite and mercuric chloride in rabbits exhibits similarities to the synthetic Hg-Se-S species. The underlying molecular mechanism for the formation of the Hg-Se-S species is discussed. C1 Stanford Synchrotron Radiat Lab, SLAC, Stanford, CA 94309 USA. Univ Arizona, Dept Cellular & Mol Biol, Tucson, AZ 85721 USA. Univ Arizona, Dept Chem, Tucson, AZ 85721 USA. ExxonMobil Res & Engn Co, Annandale, NJ 08801 USA. Univ Arizona, Coll Pharm, Dept Pharmacol & Toxicol, Tucson, AZ 85721 USA. RP George, GN (reprint author), Stanford Synchrotron Radiat Lab, SLAC, POB 20450,MS 69, Stanford, CA 94309 USA. RI George, Graham/E-3290-2013; Pickering, Ingrid/A-4547-2013; OI Prince, Roger/0000-0002-5174-4216; Pickering, Ingrid/0000-0002-0936-2994 FU NIGMS NIH HHS [GM57375] NR 49 TC 105 Z9 108 U1 3 U2 28 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0893-228X J9 CHEM RES TOXICOL JI Chem. Res. Toxicol. PD NOV PY 2000 VL 13 IS 11 BP 1135 EP 1142 DI 10.1021/tx000050h PG 8 WC Chemistry, Medicinal; Chemistry, Multidisciplinary; Toxicology SC Pharmacology & Pharmacy; Chemistry; Toxicology GA 376ML UT WOS:000165461300008 PM 11087435 ER PT J AU Nyman, M Bonhomme, F Teter, DM Maxwell, RS Gu, BX Wang, LM Ewing, RC Nenoff, TM AF Nyman, M Bonhomme, F Teter, DM Maxwell, RS Gu, BX Wang, LM Ewing, RC Nenoff, TM TI Integrated experimental and computational methods for structure determination and characterization of a new, highly stable cesium silicotitanate phase, Cs2TiSi6O15 (SNL-A) SO CHEMISTRY OF MATERIALS LA English DT Article ID SI-29 MAS NMR; POWDER DIFFRACTION PATTERNS; TOTAL-ENERGY CALCULATIONS; ION-EXCHANGE PROPERTIES; WAVE BASIS-SET; MOLECULAR-DYNAMICS; CRYSTAL-STRUCTURES; BRILLOUIN-ZONE; CHEMICAL-SHIFT; SPECIAL POINTS AB Exploratory hydrothermal synthesis in the system Cs2O-SiO2-TiO2 has produced a new polymorph of Cs2TiSi6O15 (SNL-A), whose structure was determined using a combination of experimental and theoretical techniques (Si-29 and Cs-133 NMR, X-ray powder diffraction, and density functional theory). SNL-A crystallizes in the monoclinic space group Cc with unit cell parameters a = 12.998(2) Angstrom, b = 7.5014(3) Angstrom, c = 15.156(3) Angstrom, and beta = 105.80(3)degrees. The SNL-A framework is an unbranched drier single-layer silicate with silicon tetrahedra and titanium octahedra that are linked in 3-, 5-, 6-, 7-, and 8-membered rings in three dimensions. SNL-A is distinctive from a previously reported C2/c polymorph of Cs2TiSi6O15 by orientation of the Si2O52- layers and by different ring geometries. Similarities and differences between the two structures are discussed. Other characterizations of SNL-A include TGA-DTA, Cs/Si/Ti elemental analyses, and SEM/EDS. Furthermore, the chemical and radiation durability of SNL-A was studied in interest of ceramic waste form applications. These studies show that SNL-A is durable in both radioactive and rigorous chemical environments. Finally, calculated cohesive energies of the two CS2TiSi6O15 polymorphs suggest that the Cc SNL-A phase (synthesized at 200 degreesC) is energetically more favorable than the C2/c polymorph (synthesized at 1050 degreesC). C1 Sandia Natl Labs, Catalysis & Chem Technol Dept, Albuquerque, NM 87185 USA. Sandia Natl Labs, Dept Geochem, Albuquerque, NM 87185 USA. Lawrence Livermore Natl Lab, Analyt & Nucl Sci Div, Livermore, CA 94551 USA. Univ Michigan, Dept Nucl Engn & Radiol Sci, Ann Arbor, MI 48109 USA. RP Sandia Natl Labs, Catalysis & Chem Technol Dept, POB 5800,MS 0710, Albuquerque, NM 87185 USA. NR 54 TC 33 Z9 33 U1 3 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0897-4756 EI 1520-5002 J9 CHEM MATER JI Chem. Mat. PD NOV PY 2000 VL 12 IS 11 BP 3449 EP 3458 DI 10.1021/cm000259g PG 10 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 376NC UT WOS:000165462800034 ER PT J AU Diamandis, EP Yousef, GM Clements, J Ashworth, LK Yoshida, S Egelrud, T Nelson, PS Shiosaka, S Little, S Lilja, H Stenman, UH Rittenhouse, HG Wain, H AF Diamandis, EP Yousef, GM Clements, J Ashworth, LK Yoshida, S Egelrud, T Nelson, PS Shiosaka, S Little, S Lilja, H Stenman, UH Rittenhouse, HG Wain, H TI New nomenclature for the human tissue kallikrein gene family SO CLINICAL CHEMISTRY LA English DT Article ID PROSTATE-SPECIFIC ANTIGEN; HUMAN GLANDULAR KALLIKREIN; CORNEUM CHYMOTRYPTIC ENZYME; SERINE-PROTEASE; MOLECULAR-CLONING; HORMONAL-REGULATION; KININOGENASE ACTIVITY; EXPRESSION; BREAST; MEMBER C1 Mt Sinai Hosp, Dept Pathol & Lab Med, Toronto, ON M5G 1X5, Canada. Univ Toronto, Dept Lab Med & Pathobiol, Toronto, ON M5G 1L5, Canada. Queensland Univ Technol, Sch Life Sci, Ctr Mol Biotechnol, Brisbane, Qld 4001, Australia. Lawrence Livermore Natl Lab, Ctr Human Genome, Biol & Biotechnol Res Program, Livermore, CA 94551 USA. Nara Inst Sci & Technol, Div Struct Cell Biol, Nara 6300101, Japan. Umea Univ Hosp, Dept Dermatol, S-90185 Umea, Sweden. Univ Washington, Dept Mol Biotechnol, Seattle, WA 98105 USA. Lilly Res Labs, Cent Nervous Syst Res, Indianapolis, IN 46285 USA. Lund Univ, Dept Lab Med, Div Clin Chem, S-20502 Malmo, Sweden. Univ Helsinki, Cent Hosp, Dept Clin Chem, FIN-00290 Helsinki, Finland. Hybritech Inc, San Diego, CA 92196 USA. UCL, Galton Lab, Human Gene Nomenclature Comm, London NW1 2HE, England. RP Diamandis, EP (reprint author), Mt Sinai Hosp, Dept Pathol & Lab Med, 600 Univ Ave, Toronto, ON M5G 1X5, Canada. EM ediamandis@mtsinai.on.ca RI Shiosaka, Sadao/B-1142-2008; OI Lilja, Hans/0000-0001-5871-7846; Diamandis, Eleftherios/0000-0002-1589-820X; Clements, Judith/0000-0001-6026-1964 NR 36 TC 150 Z9 157 U1 0 U2 5 PU AMER ASSOC CLINICAL CHEMISTRY PI WASHINGTON PA 2101 L STREET NW, SUITE 202, WASHINGTON, DC 20037-1526 USA SN 0009-9147 J9 CLIN CHEM JI Clin. Chem. PD NOV PY 2000 VL 46 IS 11 BP 1855 EP 1858 PG 4 WC Medical Laboratory Technology SC Medical Laboratory Technology GA 372HR UT WOS:000165228700026 PM 11067830 ER PT J AU Meier, W Barlow, RS Chen, YL Chen, JY AF Meier, W Barlow, RS Chen, YL Chen, JY TI Raman/Rayleigh/LIF measurements in a turbulent CH4/H-2/N-2 jet diffusion flame: Experimental techniques and turbulence-chemistry interaction SO COMBUSTION AND FLAME LA English DT Article ID SPONTANEOUS RAMAN; SCATTERING; LIF; OH AB Single-shot Raman, Rayleigh, and laser-induced fluorescence (LIF) measurements have been performed simultaneously in a turbulent jet flame (Re = 15,200) in order to determine joint probability density functions of temperature, mixture fraction, major species (CH4, H-2, O-2, N-2, H2O, CO2, CO), and minor species (OH, NO) mass fractions. The flame is used as a "standard flame" within the TNF Workshop, and therefore, comprehensive and accurate data sets are required to allow a quantitative comparison with predictions from computational fluid dynamics (CFD) calculations. In the first part of the paper, the results obtained at the Sandia National Laboratories are compared with those from Raman/Rayleigh measurements performed earlier at the Deutsches Zentrum fur Luft-und Raumfahrt, or German Aerospace Center (DLR). The agreement between the different data sets is generally good, and most of the observed deviations are within experimental uncertainties. The remaining discrepancies are discussed. The main issues of the second part are the characterization of the thermochemical state of the flame and the study of the influence of increasing the Reynolds number to Re = 22,800. Effects of finite-rate chemistry, local flame extinction, NO formation, and nonequilibrium concentrations are discussed. (C) 2000 by The Combustion Institute. C1 DLR, Inst Verbrennungstech, D-70569 Stuttgart, Germany. Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. Univ Tennessee, Inst Space, Tullahoma, TN 37388 USA. Univ Calif Berkeley, Dept Mech Engn, Berkeley, CA 94720 USA. RP Meier, W (reprint author), DLR, Inst Verbrennungstech, Pfaffenwaldring 38, D-70569 Stuttgart, Germany. NR 16 TC 117 Z9 121 U1 1 U2 27 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 NOV PY 2000 VL 123 IS 3 BP 326 EP 343 DI 10.1016/S0010-2180(00)00171-1 PG 18 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 364GT UT WOS:000089884600003 ER PT J AU Muske, KR Howse, JW Hansen, GA Cagliostro, DJ AF Muske, KR Howse, JW Hansen, GA Cagliostro, DJ TI Model-based control of a thermal regenerator. Part 2: control and estimation SO COMPUTERS & CHEMICAL ENGINEERING LA English DT Article DE model-based control; nonlinear control; state and parameter estimation AB This paper describes the model-based control and estimation techniques implemented on the hot blast stoves for the number 7 blast furnace at the Ispat Inland Steel facility in East Chicago, IN. The process model is a detailed heat transfer model of this thermal regenerator system used as part of a predictive control scheme to determine the minimum amount of fuel necessary to achieve the energy requirements. Batch nonlinear least squares estimation is used to update the predicted temperature profile and heat transfer coefficients. These estimated parameters are then used by the model-based controller to determine the minimum fuel required for the subsequent regenerative cycle. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Villanova Univ, Dept Chem Engn, Villanova, PA 19085 USA. Univ Calif Los Alamos Natl Lab, Computat Sci Methods Grp, Los Alamos, NM 87545 USA. RP Muske, KR (reprint author), Villanova Univ, Dept Chem Engn, Villanova, PA 19085 USA. NR 14 TC 3 Z9 3 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0098-1354 J9 COMPUT CHEM ENG JI Comput. Chem. Eng. PD NOV 1 PY 2000 VL 24 IS 11 BP 2507 EP 2517 DI 10.1016/S0098-1354(00)00613-X PG 11 WC Computer Science, Interdisciplinary Applications; Engineering, Chemical SC Computer Science; Engineering GA 372RL UT WOS:000165247800011 ER PT J AU Muske, KR Howse, JW Hansen, GA Cagliostro, DJ AF Muske, KR Howse, JW Hansen, GA Cagliostro, DJ TI Model-based control of a thermal regenerator. Part 1. dynamic model SO COMPUTERS & CHEMICAL ENGINEERING LA English DT Article DE physical dynamic modeling; model-based control; heat transfer model AB This paper describes the dynamic process model and solution technique developed for the hot blast stoves used with the No. 7 blast furnace at the Ispat Inland Steel facility in East Chicago, IN, USA. A detailed, distributed parameter, heat transfer model of this thermal regenerator system is developed and verified using plant data. The model is capable of predicting accurately the temperature and energy content of the stoves during the thermal regenerative cycles. It was developed for a predictive controller that determines the minimum amount of fuel necessary to achieve the energy requirements from the system. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Villanova Univ, Dept Chem Engn, Villanova, PA 19085 USA. Univ Calif Los Alamos Natl Lab, Computat Sci Methods Grp, Los Alamos, NM 87545 USA. RP Muske, KR (reprint author), Villanova Univ, Dept Chem Engn, Villanova, PA 19085 USA. NR 23 TC 4 Z9 5 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0098-1354 J9 COMPUT CHEM ENG JI Comput. Chem. Eng. PD NOV 1 PY 2000 VL 24 IS 11 BP 2519 EP 2531 DI 10.1016/S0098-1354(00)00614-1 PG 13 WC Computer Science, Interdisciplinary Applications; Engineering, Chemical SC Computer Science; Engineering GA 372RL UT WOS:000165247800012 ER PT J AU Tholudur, A Ramirez, WF McMillan, JD AF Tholudur, A Ramirez, WF McMillan, JD TI Interpolated parameter functions for neural network models SO COMPUTERS & CHEMICAL ENGINEERING LA English DT Article DE neural networks; parameter function modeling; interpolation; prediction; fermentation; cellulase production; Trichoderma reesei ID PROTEIN-PRODUCTION; OPTIMIZATION AB The method of neural network parameter function modeling has been demonstrated to be very effective in modeling the complex dynamics of cell growth and protein production in biotechnology processes. The development of neural network models usually requires large amounts of experimental data. This work examines the ability to use interpolated parameter functions in conjunction with neural network parameter function models to reduce the number of experiments required to develop neural network-based models of dynamic systems. Simulation and experimental results confirming the efficiency of the proposed method are presented. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Colorado, Dept Chem Engn, Boulder, CO 80309 USA. Natl Renewable Energy Lab, Biotechnol Ctr Fuels & Chem, Golden, CO 80401 USA. RP Ramirez, WF (reprint author), Univ Colorado, Dept Chem Engn, Boulder, CO 80309 USA. NR 13 TC 7 Z9 9 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0098-1354 J9 COMPUT CHEM ENG JI Comput. Chem. Eng. PD NOV 1 PY 2000 VL 24 IS 11 BP 2545 EP 2553 DI 10.1016/S0098-1354(00)00615-3 PG 9 WC Computer Science, Interdisciplinary Applications; Engineering, Chemical SC Computer Science; Engineering GA 372RL UT WOS:000165247800014 ER PT J AU Drach, R AF Drach, R TI Serving scientific data over the web SO COMPUTING IN SCIENCE & ENGINEERING LA English DT Article C1 Univ Calif Lawrence Livermore Natl Lab, Program Climate Model Diag & Intercomparison, Livermore, CA 94550 USA. RP Drach, R (reprint author), Univ Calif Lawrence Livermore Natl Lab, Program Climate Model Diag & Intercomparison, Livermore, CA 94550 USA. NR 4 TC 2 Z9 2 U1 0 U2 1 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 1521-9615 J9 COMPUT SCI ENG JI Comput. Sci. Eng. PD NOV-DEC PY 2000 VL 2 IS 6 BP 14 EP 18 DI 10.1109/5992.881702 PG 5 WC Computer Science, Interdisciplinary Applications SC Computer Science GA 369HU UT WOS:000165060500004 ER PT J AU Lillard, RS Enos, DG Scully, JR AF Lillard, RS Enos, DG Scully, JR TI Calcium hydroxide as a promoter of hydrogen absorption in 99.5% Fe and a fully pearlitic 0.8% C steel during electrochemical reduction of water SO CORROSION LA English DT Article DE calcium hydroxide; films; hydrogen; iron; overpotential; pearlitic steel; pH ID X-RAY PHOTOELECTRON; MILD-STEEL; IRON; EVOLUTION; ENTRY; EMBRITTLEMENT; SPECTROSCOPY; ADSORPTION; TRANSPORT; METALS AB Calcium hydroxide (Ca[OH](2)) surface films were found to enhance the efficiency of hydrogen absorption over a range of hydrogen overpotentials for cold-worked 99.5% alpha Fe and isothermally transformed 0.8% C pearlitic steel (AISI 1080) during galvanostatic charging. Devanathan/Stachurski permeation experiments were conducted on Fe and AISI 1080 steelfoils in a range of solutions including sodium hydroxide (NaOH, pH 12.5), saturated Ca(OH)(2) (pH 12.5), saturated Ca(OH)(2) (adjusted to pH 9.2), ASTM artificial ocean water (pH 8.2), and a buffered Ca++/Cl- solution (pH 6). Additional permeation experiments also were conducted on foils with a mortar cover. The true surface overpotential was calculated by correcting for an increased pH at the surface caused by hydroxyl formation during water reduction. The steady-state hydrogen permeation flux was only enhanced over the range of true hydrogen overpotentials in high pH solutions containing Call. Auger and x-ray photoelectron spectroscopy (XPS) analysis of the surface of foils; charged in Call solutions were consistent with the presence of a Ca(OH)(2) surface film. The presence of calcium hydride (CaH2), calcium oxide (CaO), and calcium carbonate (CaCO3) was ruled out on thermodynamic grounds. Diagnostic experiments suggest that Ca(OH)(2) lowers the rate constant for H desorption and, possibly, raises the rate constant for absorption of H. C1 Los Alamos Natl Lab, Div Mat Sci & Technol, Mat Corros & Environm Effects Lab, Los Alamos, NM 87545 USA. Univ Virginia, Dept Mat Sci & Engn, Ctr Electrochem Sci & Engn, Charlottesville, VA 22904 USA. RP Lillard, RS (reprint author), Los Alamos Natl Lab, Div Mat Sci & Technol, Mat Corros & Environm Effects Lab, MST-6, Los Alamos, NM 87545 USA. NR 52 TC 9 Z9 9 U1 0 U2 3 PU NATL ASSN CORROSION ENG PI HOUSTON PA 1440 SOUTH CREEK DRIVE, HOUSTON, TX 77084-4906 USA SN 0010-9312 J9 CORROSION JI Corrosion PD NOV PY 2000 VL 56 IS 11 BP 1119 EP 1132 PG 14 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 565DZ UT WOS:000176354800006 ER PT J AU Holcomb, GR Covino, BS Russell, JH Bullard, SJ Cramer, SD Collins, WK Bennett, JE Laylor, HM AF Holcomb, GR Covino, BS Russell, JH Bullard, SJ Cramer, SD Collins, WK Bennett, JE Laylor, HM TI Humectant use in the cathodic protection of reinforced concrete SO CORROSION LA English DT Article DE cathodic protection; humectant; lithium bromide; lithium nitrate; reinforced concrete; thermal spray; zinc ID BRIDGES AB Use of humectants to improve the thermal-sprayed zinc anode performance during the cathodic protection (CP) of reinforced concrete was examined. A humectant is a hygroscopic material. It is applied onto the surface of the zinc anode to keep the concrete-anode interface moist and a good conductor. The thermodynamics of humectants are discussed. Laboratory results are presented on the effects of using lithium bromide (LiBr) and lithium nitrate (LiNO3) as humectants in galvanic cathodic protection (GCP) and impressed current cathodic protection (ICCP) systems, in high and low relative humidities, and on new and previously electrochemically aged CP systems. LiNO3 and LiBr promoted more effective CP performance. Both improved the performance of aged slabs, suggesting that application of humectants onto existing CP systems would be beneficial. Microscopy showed that humectant-treated slabs develop the same cement-reaction zone, zinc anode structures as untreated slabs. Microscopy of LiBr-treated slabs revealed that the highest concentration of bromide was in the reaction zone. In GCP tests, LiBr was more effective than LiNO3. In accelerated ICCP tests, LiNO3 was more effective than LiBr. It was surmised that bromide could be oxidized in the high-voltage, accelerated ICCP tests. At the lower impressed currents of most installed ICCP systems, LiBr may perform as well as or better than LiNO3. C1 US DOE, Albany Res Ctr, Albany, OR 97321 USA. JE Bennett Consulting Inc, Chardon, OH 44024 USA. Oregon Dept Transportat, Salem, OR 97310 USA. RP Holcomb, GR (reprint author), US DOE, Albany Res Ctr, 1450 Queen Ave SW, Albany, OR 97321 USA. RI Holcomb, Gordon/G-9070-2013 OI Holcomb, Gordon/0000-0003-3542-5319 NR 19 TC 3 Z9 4 U1 0 U2 0 PU NATL ASSN CORROSION ENG PI HOUSTON PA 1440 SOUTH CREEK DRIVE, HOUSTON, TX 77084-4906 USA SN 0010-9312 J9 CORROSION JI Corrosion PD NOV PY 2000 VL 56 IS 11 BP 1140 EP 1157 PG 18 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 565DZ UT WOS:000176354800008 ER PT J AU Kolman, DG Scully, JR AF Kolman, DG Scully, JR TI An assessment of the crack tip potential of beta-titanium alloys during hydrogen environmentally assisted crack propagation based on crack tip and passive surface electrochemical measurements SO CORROSION SCIENCE LA English DT Article DE titanium; chloride; hydrogen-assisted cracking; ohmic loss; crack tip potential ID AQUEOUS CHLORIDE SOLUTIONS; BETA+ALPHA TITANIUM; BEHAVIOR AB We have previously proposed a scenario for intergranular hydrogen-assisted crack initiation of metastable p-titanium alloys exposed to aqueous chloride solution. This scenario requires the loss of potentiostatic control due to ohmic drop in solution such that the crack tip potential falls to a potential where hydrogen production is viable regardless of the applied potential. It is of interest to examine the crack tip potential during crack growth to discern whether hydrogen production is viable during crack growth as well. Crack tip potential excursions were examined by analyzing crack tip and passive film currents. The magnitude of the galvanic currents between filmed surfaces and the bare crack tip were estimated using a model compact tension specimen, which comprises a fixture with a similar geometry to an actual compact tension specimen. These experiments indicate that capacitive charging and discharging occurs on the passive surfaces surrounding a depassivated crack tip. High speed measurements of crack tip anodic current during potentiostatic crack growth indicate that coupling of the crack tip to the counter electrode is incomplete. Unaccounted charge suggests that a significant amount of current is supplied by the bare surface itself and that the crack tip approaches its bare surface open circuit potential during crack growth. Thus, hydrogen production was found to be viable during crack growth even though the applied potential was more positive than the reversible potential for hydrogen production. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Virginia, Dept Mat Sci, Ctr Electrochem Sci & Engn, Charlottesville, VA 22903 USA. RP Kolman, DG (reprint author), Univ Calif Los Alamos Natl Lab, Mat Corros & Environm Effects Lab, MS G755, Los Alamos, NM 87545 USA. NR 23 TC 8 Z9 9 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0010-938X J9 CORROS SCI JI Corrosion Sci. PD NOV PY 2000 VL 42 IS 11 BP 1863 EP 1879 DI 10.1016/S0010-938X(00)00033-0 PG 17 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 359XP UT WOS:000089637600002 ER PT J AU Larson, EJ Hakovirta, JR Cai, H Jett, JH Burde, S Keller, RA Marrone, BL AF Larson, EJ Hakovirta, JR Cai, H Jett, JH Burde, S Keller, RA Marrone, BL TI Rapid DNA fingerprinting of pathogens by flow cytometry SO CYTOMETRY LA English DT Article DE flow cytometry; pulsed-field gel electrophoresis; DNA fingerprinting ID FIELD GEL-ELECTROPHORESIS; STAPHYLOCOCCUS-AUREUS; FLUORESCENCE DETECTION; VANCOMYCIN RESISTANCE; ARBITRARY PRIMERS; FRAGMENTS; MOLECULES; PATTERNS; MARKERS; STRAIN AB Background: A new method for rapid discrimination among bacterial strains based on DNA fragment sizing by low cytometry is presented. This revolutionary approach combines the reproducibility and reliability of restriction fragment length polymorphism (RFLP) analysis with the speed and sensitivity of now cytometry. Methods: Bacterial genomic DNA was isolated and digested with a rare-cutting restriction endonuclease. The resulting fragments were stained stoichiometrically with PicoGreen dye and introduced into an ultrasensitive flow cytometer. A histogram of burst sizes from the restriction fragments (linearly related to fragment length in base pairs) resulted in a DNA fingerprint that was used to distinguish among different bacterial strains. Results: Five different strains of gram-negative Escherichia coli and six different strains of gram-positive Staphylococcus nul eus were distinguished by analyzing their restriction fragments with DNA fragment sizing by flow cytometry. Fragment distribution analpses of extracted DNA were similar to 100 times faster and similar to 200,000 times more sensitive than pulsed-field gel electrophoresis (PFGE). When sample preparation time is included, the total DNA fragment analysis time was approximately 8 h by flow cytometry and approximately 24 h by PFGE. Conclusions: DNA fragment sizing by flow cytometry is a fast and reliable technique that can be applied to the discrimination among species and strains of human pathogens. Unlike some polymerase chain reaction (PCR)based methods, sequence information about the bacterial strains is not required, allowing the detection of unknown, newly emerged, or unanticipated strains. Published 2000 Wiley-Liss, Inc.(dagger) C1 Univ Calif Los Alamos Natl Lab, Biosci Div, Los Alamos, NM 87545 USA. RP Marrone, BL (reprint author), Univ Calif Los Alamos Natl Lab, Biosci Div, Mail Stop M888, Los Alamos, NM 87545 USA. FU NCRR NIH HHS [RR-01315] NR 33 TC 16 Z9 20 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 0196-4763 J9 CYTOMETRY JI Cytometry PD NOV 1 PY 2000 VL 41 IS 3 BP 203 EP 208 DI 10.1002/1097-0320(20001101)41:3<203::AID-CYTO7>3.0.CO;2-2 PG 6 WC Biochemical Research Methods; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 368LX UT WOS:000090119400007 PM 11042617 ER PT J AU Tucker, JB Rao, MV Holland, OW Chi, PH Braga, GCB Freitas, JA Papanicolaou, N AF Tucker, JB Rao, MV Holland, OW Chi, PH Braga, GCB Freitas, JA Papanicolaou, N TI Material and n-p junction characteristics of As- and Sb-implanted SiC SO DIAMOND AND RELATED MATERIALS LA English DT Article DE SiC; ion-implantation; arsenic; antimony ID HIGH-POWER DEVICES; SILICON-CARBIDE; ION-IMPLANTATION; NITROGEN IMPLANTS; EPITAXIAL LAYERS; ACTIVATION; PHOTOLUMINESCENCE; SIMULATION; BEHAVIOR; DEFECTS AB Single and multiple energy As and Sb implantations were performed into p-type 6H-SiC epitaxial layers at room temperature (RT) and 800 degreesC. Secondary ion mass spectrometry measurements showed severe implant loss for annealing temperatures > 1500 degreesC. Rutherford backscattering spectroscopy/channeling (RBS/C) measurements indicated a high degree of residual lattice damage for RT implantations even after 1600 degreesC annealing while less damage was detected in 800 degreesC implanted samples. Electrical activations (ratios of sheet carrier concentrations to implant doses) of 11 and 20% were measured for 800 degreesC As and Sb implantations annealed at 1500 degreesC, respectively. The Schottky capacitance-voltage profiling measurements indicated substitutional concentrations in the low 10(18) cm(-3) range for both As and Sb. Based on the experimental data, carrier ionization energies of 130 and 88 meV were estimated for As and Sb donors, respectively. Vertical n-p junction diodes were made by using multiple energy As and Sb implanted epitaxial layers Elevated temperature As implanted diodes exhibited a room temperature reverse leakage current of approximate to 8 x 10 A/cm(2) with no passivation at - 100 V bias and a forward series resistance of 460 Ohm. (C) 2000 Elsevier Science B.V. All rights reserved. C1 George Mason Univ, Dept Elect & Comp Engn, Fairfax, VA 22030 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. USN, Res Lab, Washington, DC 20375 USA. RP Rao, MV (reprint author), George Mason Univ, Dept Elect & Comp Engn, Fairfax, VA 22030 USA. NR 43 TC 3 Z9 3 U1 1 U2 2 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-9635 J9 DIAM RELAT MATER JI Diam. Relat. Mat. PD NOV PY 2000 VL 9 IS 11 BP 1887 EP 1896 DI 10.1016/S0925-9635(00)00340-X PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA 371RC UT WOS:000165191100009 ER PT J AU Marinkovic, NS Wang, JX Zajonz, H Adzic, RR AF Marinkovic, NS Wang, JX Zajonz, H Adzic, RR TI Unusual stability of carbon monoxide adsorbed on the Ru(0001) electrode surface SO ELECTROCHEMICAL AND SOLID STATE LETTERS LA English DT Article ID RUTHENIUM ELECTRODE; METHANOL OXIDATION; OXYGEN REDUCTION; CO OXIDATION; ADSORPTION; PT(111); ELECTROOXIDATION; SPECTROSCOPY; ALLOYS AB Adsorption and oxidation of carbon monoxide have been studied on Ru(0001) single crystal and polycrystalline surfaces in sulfuric acid solutions by in situ Fourier transform infrared spectroscopy and electrochemical techniques. Carbon monoxide adsorbs on Ru( 0001) in linear and threefold bonding configurations, while only a linear configuration has been observed on polycrystalline surfaces. No CO oxidation can be discerned from the infrared spectra, because no CO2 band is observed up to 0.9 V, in sharp contrast with the facile reaction on polycrystalline surfaces. Voltammetry shows a negligible oxidation at very positive potentials. Oxidation of Ru( 0001) surface is limited to a one electron per Ru atom process, distinctly different from a high degree of oxidation of polycrystalline Ru. A limited oxidation of Ru( 0001) is likely the cause of the inactivity of Ru( 0001) for CO oxidation, which suggests an important role of the Ru surface structure and the form of ruthenium oxide in catalyzing CO oxidation. (C) 2000 The Electrochemical Society. S1099-0062(00)05-087-2. All rigths reserved. C1 Brookhaven Natl Lab, Dept Appl Sci, Div Chem & Mat Sci, Upton, NY 11973 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Marinkovic, NS (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Div Chem & Mat Sci, Upton, NY 11973 USA. RI Wang, Jia/B-6346-2011; Marinkovic, Nebojsa/A-1137-2016 OI Marinkovic, Nebojsa/0000-0003-3579-3453 NR 21 TC 25 Z9 25 U1 0 U2 11 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 65 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 1099-0062 J9 ELECTROCHEM SOLID ST JI Electrochem. Solid State Lett. PD NOV PY 2000 VL 3 IS 11 BP 508 EP 510 PG 3 WC Electrochemistry; Materials Science, Multidisciplinary SC Electrochemistry; Materials Science GA 353MA UT WOS:000089277100005 ER PT J AU Halley, JW Schelling, P Duan, Y AF Halley, JW Schelling, P Duan, Y TI Simulation methods for chemically specific modeling of electrochemical interfaces SO ELECTROCHIMICA ACTA LA English DT Article; Proceedings Paper CT 50th Annual Meeting of the International-Society-of-Electrochemistry (ISE) CY SEP 05-10, 1999 CL PAVIA, ITALY SP Int Soc Electrochem DE simulation; modeling; electrochemical interfaces ID DENSITY-FUNCTIONAL THEORY; METAL-WATER INTERFACE; ELECTRON-TRANSFER; MOLECULAR-DYNAMICS; POLYETHYLENE OXIDE; CHARGE AB We present progress in simulation of electrochemical interfaces. The problem is one of a larger class of materials related simulation challenges in which one needs to couple calculations spanning about 10 orders of magnitude in length and time scale in order to produce macroscopic predictions. Generally, methods within each scale are available but robust and reliable methods for coupling one scale to another are not. We discuss methods for coupling the electronic structure scale to the atomic scale and the atomic scale to higher length scales. At the electronic scale, quantum chemical, Hartree-Fock based methods and solid-state, density functional methods, while working from the same principles, are both useful in the appropriate electrochemical context. To study oxides, methods in which tight binding molecular dynamics models are fitted to plane wave local density electronic structure results with applications to titania and other rutile structure oxides are described in more detail. At the higher scale, we discuss progress on renormalization of molecular dynamics to permit it to be used on longer time and length scales in the context of studies of polymer electrolytes of interest in battery development programs. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP Halley, JW (reprint author), Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. NR 20 TC 9 Z9 9 U1 1 U2 8 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0013-4686 J9 ELECTROCHIM ACTA JI Electrochim. Acta PD NOV 1 PY 2000 VL 46 IS 2-3 BP 239 EP 245 DI 10.1016/S0013-4686(00)00578-8 PG 7 WC Electrochemistry SC Electrochemistry GA 383YQ UT WOS:000165912600011 ER PT J AU Johnson, DC Feng, J Houk, LL AF Johnson, DC Feng, J Houk, LL TI Direct electrochemical degradation of organic wastes in aqueous media SO ELECTROCHIMICA ACTA LA English DT Article; Proceedings Paper CT 50th Annual Meeting of the International-Society-of-Electrochemistry (ISE) CY SEP 05-10, 1999 CL PAVIA, ITALY SP Int Soc Electrochem DE malonic acid; acetic acid; cyanuric acid; oxidation; degradation ID OXYGEN-TRANSFER REACTIONS; HIGH OVERVOLTAGE ANODES; WATER TREATMENT; SNO2 ANODES; OXIDATION; PHENOL; ELECTROCATALYSIS; INCINERATION; ATRAZINE; BENZOQUINONE AB The goals of research reported here include the discovery of optimal electrocatalytic materials and electrolysis conditions for rapid degradation of organic compounds to CO2(g). Concepts of the designated procedure are summarized with emphasis on the carboxylic acids generated as intermediate products during anodic degradation of 4-chlorophenol and benzoquinone. Data are summarized for various electrode materials including oxide-covered Pt, as well as PbO2 and SnO2 films that are heavily doped with altervalent metallic cations. The anodic degradation reactions have in common the fact that they involve transfer of O-atoms from H2O in the solvent phase to the oxidation products. Therefore, variations in reactivity of electrode materials are ascribed to differences in the extent of electrocatalytic participation of these electrode surfaces within the anodic O-transfer mechanisms. Results are explained on the basis of the following mechanistic speculations: (1) a prerequisite of the required anodic O-transfer reactions is the discharge of H2O to generate adsorbed hydroxyl radicals; (2) a co-requisite is preadsorption of the reactant species; (3) the O-transfer step occurs from (OH)(ads) to (R)(ads); and (4) an inevitable but undesirable concomitant reaction is the anodic evolution of O-2(g). The expected benefit of elevated anode temperature is verified for degradation of acetic acid at a Pt anode. Also, cyanuric acid generated as a stable product of photocatalytic degradation processes is demonstrated to be degraded by anodic reaction at a Pt electrode. Recovery of nitrate is approximately 70% during degradation of cyanuric acid and it is speculated that some volatile N-species is lost during the procedure. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Iowa State Univ, Ames Lab, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, Microanalyt Instrumentat Ctr, Ames, IA 50011 USA. RP Johnson, DC (reprint author), Iowa State Univ, Ames Lab, Dept Chem, Ames, IA 50011 USA. NR 30 TC 124 Z9 134 U1 2 U2 44 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0013-4686 J9 ELECTROCHIM ACTA JI Electrochim. Acta PD NOV 1 PY 2000 VL 46 IS 2-3 BP 323 EP 330 DI 10.1016/S0013-4686(00)00588-0 PG 8 WC Electrochemistry SC Electrochemistry GA 383YQ UT WOS:000165912600021 ER PT J AU Liang, DH Song, LG Quesada, MA Tian, ZW Studier, FW Chu, B AF Liang, DH Song, LG Quesada, MA Tian, ZW Studier, FW Chu, B TI Formation of concentration gradient and its application to DNA capillary electrophoresis SO ELECTROPHORESIS LA English DT Article DE concentration gradient; enhancement; average concentration ID POLYMER-SOLUTIONS; POINT MUTATIONS; SEPARATION; FRAGMENTS; PROTEINS AB A new method to introduce the concentration gradient into the capillary has been developed and its application to DNA capillary electrophoresis is presented. The concentration gradient produced by mixing 5% w/v polyacrylamide-co-poly(N-dimethylacrylamide) (PAM-co-PDMA) solution and 1 x Tris/N-tris(hydroxymethyl)methyl-3-amino-propanesulfonic acid/EDTA (TT) + 5 M urea buffer was successfully achieved by using two programmable syringe pumps with strict control of dead volume, flow rate, and pressure balance. This method has the advantages of high stability, reproducibility, and versatility. The column with concentration gradient greatly improved the resolution, especially for the large DNA fragments, due to a decrease in band width broadening with time. A column containing 2-4% w/v gradient in four steps had a longer read length, shorter separation time and better resolution (after 380 base) than that of 4% w/v single concentration polymer solution. The number of steps in the gradient had almost no effect on the performance. The change in the average concentration by relocating the position of the same step gradient, i.e., a combination of different low concentration to high concentration polymer solution ratios, resulted in a different migration time, read length and resolution. C1 SUNY Stony Brook, Dept Chem, Stony Brook, NY 11794 USA. Corning Inc, Corning, NY 14831 USA. Xiamen Univ, Dept Chem, Xiamen 361005, Peoples R China. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Chu, B (reprint author), SUNY Stony Brook, Dept Chem, Stony Brook, NY 11794 USA. RI Tian, ZW/G-3410-2010 FU NHGRI NIH HHS [2R01HG0138604] NR 23 TC 12 Z9 12 U1 1 U2 7 PU WILEY-V C H VERLAG GMBH PI BERLIN PA PO BOX 10 11 61, D-69451 BERLIN, GERMANY SN 0173-0835 J9 ELECTROPHORESIS JI Electrophoresis PD NOV PY 2000 VL 21 IS 17 BP 3600 EP 3608 DI 10.1002/1522-2683(200011)21:17<3600::AID-ELPS3600>3.3.CO;2-8 PG 9 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 379AV UT WOS:000165619500010 PM 11271477 ER PT J AU Seshadri, KS Smith, DH AF Seshadri, KS Smith, DH TI Strengths and chemistry of filter cakes from pressurized fluidized bed combustion SO ENERGY & FUELS LA English DT Article ID MGSO4; CASO4; MG2CA(SO4)(3); MIXTURES AB Excessively hard filter cakes have occurred during filtration of fine particles from hot gases in pressurized fluidized bed combustion (PFBC) power plants. Hence, shear strengths were measured (at 22 degreesC) for cakes formed from powders taken from the hot-gas filtration vessel of a PFBC demonstration power plant. The measurements were made both before and after heating at 750 degreesC (1 h) or at 950 degreesC (1or 3 h). Sample strengths were significantly increased by the heat treatment at 950 degreesC, but not by heating to 750 degreesC. In filter vessels operating at 750 degreesC, formation of Mg2Ca(SO4)(3) from MgO, SOx, and CaSO4 is the main cause of the development of excessive cake strengths. However, these reactions and the concomitant strength increases cannot occur in the laboratory, if plant material is heated in the absence of one or more of the reactants (MgO and/or SOx). At 950 degreesC and in the absence of coal ash, the formation of Mg2Ca(SO4)(3) occurs even more rapidly. However, at 950 degreesC, Fe2O3 and other components of coal ash promote the decomposition of Mg2Ca(SO4)3. Hence, depending on the temperature, sorbent, amount of coal ash, and its composition, formation of Mg2Ca(SO4)(3) and/or sintering of CaSO4 may be the important cause(s) of cake hardening. C1 US DOE, Natl Energy Technol Lab, Morgantown, WV 26507 USA. Parsons Infrastruct, Morgantown, WV 26505 USA. W Virginia Univ, Dept Phys, Morgantown, WV 26506 USA. RP Smith, DH (reprint author), US DOE, Natl Energy Technol Lab, Morgantown, WV 26507 USA. NR 14 TC 1 Z9 1 U1 1 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0887-0624 J9 ENERG FUEL JI Energy Fuels PD NOV-DEC PY 2000 VL 14 IS 6 BP 1200 EP 1204 DI 10.1021/ef0000835 PG 5 WC Energy & Fuels; Engineering, Chemical SC Energy & Fuels; Engineering GA 376RF UT WOS:000165470000012 ER PT J AU Norinaga, K Iino, M Cody, GD Thiyagarajan, P AF Norinaga, K Iino, M Cody, GD Thiyagarajan, P TI Characterization of micro-domain structure of solvent-swollen coal by proton spin diffusion and small angle neutron scattering SO ENERGY & FUELS LA English DT Article ID NUCLEAR MAGNETIC-RESONANCE; MACROMOLECULAR STRUCTURE; MOLECULAR-STRUCTURE; PREMIUM COAL; PULSED NMR; H-1; PYRIDINE; CROSSLINKS; WEIGHT AB The macromolecular structure of a high volatile bituminous coal (the Blind Canyon) is characterized by osmotic dilation experiments using deuterated solvents (pyridine or benzene/ pyridine mixed solvent). Nano scale structural changes were quantitatively revealed using proton spin diffusion experiments and qualitatively verified with small-angle neutron scattering (SANS) measurements. The SANS data reveal. systematic changes in the coherent scattering behavior of osmotically dilated coal particles in a binary solvent system of benzene + pyridine. These results show that volumetric strain derived from osmotic stresses results in the development of phase-separated domains at nanoscales. Quantitatively, the effect of solvent-to-coal mass ratio (S/C) on the proton relaxation characteristics was examined. It is shown that the fractional amount of mobile hydrogen yielding the exponential decay, f(MH), increased to a maximum of 0.5 with increasing solvent concentration. Above S/C = 2.24, f(MH) remained nearly constant, indicating that solvent impenetrable regions exist in the swollen coal even at SIC ratios as high as 4.72. Although there exist at least two distinct structural regions in the swollen coals based on the transverse relaxation characteristics, longitudinal relaxation experiments are fit best by a single component revealing that spin diffusion is rapid in the swollen coals. The dynamics of spin diffusion were determined using a partially modified Goldman-Shen pulse sequence and analyzed by simple geometric models of two-phase systems. The average distance between the adjacent solvent impenetrable domains, di, was estimated on the basis of the diffusive path length for each spatial dimension by employing simple one-, two-, and three-dimensional models. Estimates of di derived from the SANS data lie between those derived for the one- and two-dimensional diffusion models suggesting that the actual structure may be roughly laminar, but with sufficient curvature or other irregularity to yield diffusion behavior lying between the two simple models considered. The results of this study clearly reveal that volumetrically measured osmotic strain is not affine down to the macromolecular level. C1 Tohoku Univ, Inst Chem React Sci, Aoba Ku, Sendai, Miyagi 9808577, Japan. Carnegie Inst Washington, Geophys Lab, Washington, DC 20015 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP Norinaga, K (reprint author), Tohoku Univ, Inst Chem React Sci, Aoba Ku, Sendai, Miyagi 9808577, Japan. RI Norinaga, Koyo/A-2597-2010 NR 29 TC 8 Z9 8 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0887-0624 J9 ENERG FUEL JI Energy Fuels PD NOV-DEC PY 2000 VL 14 IS 6 BP 1245 EP 1251 DI 10.1021/ef000102a PG 7 WC Energy & Fuels; Engineering, Chemical SC Energy & Fuels; Engineering GA 376RF UT WOS:000165470000019 ER PT J AU Britt, PF Buchanan, AC Malcolm, EA AF Britt, PF Buchanan, AC Malcolm, EA TI Impact of restricted mass transport on pyrolysis pathways for aryl ether containing lignin model compounds SO ENERGY & FUELS LA English DT Article ID LOW-RANK COAL; PHENYL ETHER; SURFACE; DECOMPOSITION; THERMOLYSIS; MOLECULES; RADICALS; BIOMASS; REARRANGEMENT; DIFFUSION AB Pyrolysis studies have been conducted at 375 degreesC on several silica-immobilized phenethyl phenyl ether (PPE) model compounds, representative of related beta -O-4 aryl ether linkages in lignin, to explore the impact of restricted mass transport on reaction pathways. As found previously for fluid-phase PPE, two competitive free-radical decay pathways are operative including a significant rearrangement pathway involving an O,C-phenyl shift for surface-attached PhCH2CH . OPh radicals. The selectivity for the rearrangement pathway is found to be sensitive to substituents and, in particular, to the structure of neighboring spacer molecules on the surface. In contrast to solution-phase behavior, dilution of PPE molecules on the surface with rigid aromatic spacers such as biphenyl or naphthalene hinder the rearrangement path. This phenomenon, attributed to steric constraints that decrease the rate of the 1,2-phenyl shift, is not observed when a more flexible spacer molecule (diphenylmethane) is employed. An improved knowledge of the pathways involved is important since this rearrangement pathway, which was also observed in the pyrolysis of alpha -aryl ether models, can result in the formation of valuable chemicals (aryl aldehydes and ketones) or undesirable refractory compounds (biphenyls and diphenylmethanes) during the thermochemical processing of lignin. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Buchanan, AC (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, POB 2008, Oak Ridge, TN 37831 USA. NR 42 TC 20 Z9 20 U1 0 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0887-0624 J9 ENERG FUEL JI Energy Fuels PD NOV-DEC PY 2000 VL 14 IS 6 BP 1314 EP 1322 DI 10.1021/ef000160w PG 9 WC Energy & Fuels; Engineering, Chemical SC Energy & Fuels; Engineering GA 376RF UT WOS:000165470000028 ER PT J AU Gustavsson, L Karjalainen, T Marland, G Savolainen, I Schlamadinger, B Apps, M AF Gustavsson, L Karjalainen, T Marland, G Savolainen, I Schlamadinger, B Apps, M TI Project-based greenhouse-gas accounting: guiding principles with a focus on baselines and additionality SO ENERGY POLICY LA English DT Article DE baselines; greenhouse-gas mitigation; guiding principles ID JOINT IMPLEMENTATION; ENERGY AB Implementation of some of the articles of the Kyoto Protocol will require rules for accounting and for defining baselines against which reduction of greenhouse-gas emissions, or enhancement of greenhouse-gas removals, are to be measured. Project accounting needs to provide incentives to ensure that the objective of the United Nations Framework Convention on Climate Change (UNFCCC) is served and that the interests of all participating parties are respected. To establish the emission reduction achievements of activities is complex as it is inherently very difficult to define the counterfatctuel baseline. Here, we articulate four basic principles - accuracy, comprehensiveness, conservativeness and practicability - that can be used to guide the construction of baselines for greenhouse-gas mitigation projects. The overall aim is to have accurate, comprehensive, and conservative baselines; but this aim needs to be balanced to yield baselines that are as simple as possible, can be practically implemented, and provide incentives to fulfill the ultimate objective of the UNFCCC. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Lund, Lund Inst Technol, Dept Environm & Energy Syst Studies, SE-22362 Lund, Sweden. European Forest Inst, Joensuu, Finland. Oak Ridge Natl Lab, Oak Ridge, TN USA. VTT Energy, Espoo, Finland. Canadian Forestry Serv, Dept Nat Resources, Edmonton, AB, Canada. RP Gustavsson, L (reprint author), Univ Lund, Lund Inst Technol, Dept Environm & Energy Syst Studies, Gerdagatan 13, SE-22362 Lund, Sweden. NR 36 TC 28 Z9 29 U1 1 U2 8 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0301-4215 J9 ENERG POLICY JI Energy Policy PD NOV PY 2000 VL 28 IS 13 BP 935 EP 946 DI 10.1016/S0301-4215(00)00079-3 PG 12 WC Energy & Fuels; Environmental Sciences; Environmental Studies SC Energy & Fuels; Environmental Sciences & Ecology GA 348NG UT WOS:000088990400003 ER PT J AU Fthenakis, VM AF Fthenakis, VM TI End-of-life management and recycling of PV modules SO ENERGY POLICY LA English DT Article DE photovoltaics; recycling; decommissioning; environment; waste ID MANUFACTURE; HEALTH; ISSUES AB Photovoltaics (PV) technology is undergoing a transition to a new generation of efficient, low-cost products based on thin films of photoactive materials. PV technology has definite environmental advantages over competing electricity generation technologies, and the PV industry follows a pro-active life-cycle approach to prevent future environmental damage and to sustain these advantages. An issue with potential environmental implications is the decommissioning of solar cells at the end of their useful life; a viable answer is recycling them when they are no longer useful. This paper presents a feasibility study for recycling thin-film solar cells and manufacturing waste, based on the current collection/recycling infrastructure and on current and emerging recycling technologies. Technology already exists for recycling PV modules and costs associated with recycling are not excessive. Published by Elsevier Science Ltd. C1 Brookhaven Natl Lab, Dept Adv Technol, Environm & Waste Technol Grp, Upton, NY 11973 USA. RP Fthenakis, VM (reprint author), Brookhaven Natl Lab, Dept Adv Technol, Environm & Waste Technol Grp, POB 5000, Upton, NY 11973 USA. NR 17 TC 86 Z9 87 U1 2 U2 25 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0301-4215 J9 ENERG POLICY JI Energy Policy PD NOV PY 2000 VL 28 IS 14 BP 1051 EP 1058 DI 10.1016/S0301-4215(00)00091-4 PG 8 WC Energy & Fuels; Environmental Sciences; Environmental Studies SC Energy & Fuels; Environmental Sciences & Ecology GA 359JY UT WOS:000089608800007 ER PT J AU Amonette, JE Workman, DJ Kennedy, DW Fruchter, JS Gorby, YA AF Amonette, JE Workman, DJ Kennedy, DW Fruchter, JS Gorby, YA TI Dechlorination of carbon tetrachloride by Fe(II) associated with goethite SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID REDUCTIVE DEHALOGENATION; SURFACE-AREA; IRON; TRANSFORMATION; ENVIRONMENTS; SEDIMENTS; KINETICS; CULTURE AB Carbon tetrachloride (CT) was dechlorinated to chloroform (CF) under anoxic conditions by Fe(II) that was sorbed to the surface of goethite (alpha -FeOOH). No reaction occurred when Fe(II) was present and goethite was absent. Several abiotic experiments were conducted with goethite at 30 degreesC in which the total amount of Fe(II) in the system, the amount of sorbed Fe(II), the density of sorbed Fe(II), and the pH were varied. Regeneration of sorbed Fe(II) occurred when dissolved Fe2+ was available and maintained pseudo-first-order conditions with respect to CT. Analysis of the rates of CT loss for experiments with sorbed-Fe(II) regeneration showed the rate-determining-step to be first order with respect to CT, second order with respect to the volumetric concentration of sorbed Fe(II) (i.e., mmol sorbed Fe(II) L-1 suspension), and zero order with respect to H+ for pH between 4.2 and 7.3. The absolute rare constant for the reaction was determined to be 42 +/- 5 M-2 s(-1). Normalization of the observed rate constants to account for different goethite concentrations yielded reaction orders of one and zero, respectively, for CT and H+, and a second-order reaction with respect to the density of sorbed Fe(II) (i.e., mmol sorbed Fe(II) g(-1) goethite). On the basis of the kinetic data, the rate-determining step is proposed to be a termolecular two-electron-transfer reaction involving two Fe2+ ions sorbed to adjacent sites on the goethite surface and a CCl4 molecule that approaches the surface. The primary role of the goethite surface, thus, is to catalyze the reaction by fixing the position of the two charged reactants in a geometry suitable for reaction with CT. In separate experiments, biogenic Fe(II) formed by the enzymatic reduction of goethite by the Fe(III)-reducing bacterium Shewanella alga, strain BrY, dechlorinated CT. Of the CT degraded by abiotic and biogenic Fe(II) on goethite, 83-90% was converted to chloroform (CF), which accumulated in the reaction vial. These results indicate that dechlorination reactions in Fe(III)-reducing environments may indirectly result from the enzymatic or chemical reduction of Fe(III)-bearing minerals such as goethite. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Gorby, YA (reprint author), Pacific NW Natl Lab, Mailstop P7-50,POB 999, Richland, WA 99352 USA. OI Kennedy, David/0000-0003-0763-501X NR 41 TC 203 Z9 230 U1 10 U2 74 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 NOV 1 PY 2000 VL 34 IS 21 BP 4606 EP 4613 DI 10.1021/es9913582 PG 8 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 370JV UT WOS:000165120800043 ER PT J AU Holloman, KA Dallas, CE Jagoe, CH Tackett, R Kind, JA Rollor, EA AF Holloman, KA Dallas, CE Jagoe, CH Tackett, R Kind, JA Rollor, EA TI Interspecies differences in oxidative stress response and radiocesium concentrations in rodents inhabiting areas highly contaminated by the Chornobyl nuclear disaster SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE superoxide dismutase; catalase; radiocesium; Cs-137; Chornobyl ID ANTIOXIDANT ENZYMES; SUPEROXIDE-DISMUTASE; FREE-RADICALS; IRRADIATION; CHERNOBYL; RAT AB Indicators of oxidative stress response were compared to radionuclide concentrations in rodents from highly contaminated sites around the Chornobyl Nuclear Power Plant, Ukraine, and uncontaminated reference areas. Three rodent species-Apodemus agrarius, Apodemus sylvaticus, and Clethrionomys glareolus (n = 121)-were collected from contaminated sites within the 10-km exclusion zone surrounding the Chornobyl Nuclear Power Plant and from uncontaminated reference areas in northern Ukraine. Liver samples were analyzed for superoxide dismutase (SOD) and catalase (CAT) activities, and muscle samples were analyzed for radiocesium activity. Superoxide dismutase and catalase activities differed significantly between reference and contaminated groups only for A. agrarius, and activities were lower in contaminated animals relative to those from reference sites. The SOP activity did not differ among species collected in reference areas. Among contaminated groups, A. agrarius had a significantly lower SOD activity than the other two species. Among reference groups, CAT activity for C. glareolus was significantly lower than for the other two species. Very high muscle radiocesium activities (up to 60,000 Bq/g) were found in rodents from contaminated areas, while the references for each species were at or below background. Clethrionomys glareolus had significantly higher muscle radiocesium concentrations than the other species collected at contaminated sites. There were no significant correlations between either SOD or CAT activities and muscle radiocesium concentrations for contaminated or reference animals in any species. There are significant interspecies differences in oxidative enzyme activities in rodents with lifetime exposure at highly radioactive contaminated sites. However, internal radiocesium concentration is not a sensitive predictor of these oxidative stress responses in individuals. C1 Univ Georgia, Coll Pharm, Dept Pharmaceut & Biomed Sci, Interdisciplinary Program Toxicol, Athens, GA 30602 USA. Univ Georgia, Savannah River Ecol Lab, Interdisciplinary Program Toxicol, Aiken, SC 29802 USA. Univ Georgia, Coll Pharm, Dept Clin & Adm Sci, Athens, GA 30602 USA. RP Dallas, CE (reprint author), Univ Georgia, Coll Pharm, Dept Pharmaceut & Biomed Sci, Interdisciplinary Program Toxicol, Athens, GA 30602 USA. NR 31 TC 3 Z9 3 U1 2 U2 4 PU SETAC PI PENSACOLA PA 1010 NORTH 12TH AVE, PENSACOLA, FL 32501-3367 USA SN 0730-7268 J9 ENVIRON TOXICOL CHEM JI Environ. Toxicol. Chem. PD NOV PY 2000 VL 19 IS 11 BP 2830 EP 2834 DI 10.1897/1551-5028(2000)019<2830:IDIOSR>2.0.CO;2 PG 5 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 373BQ UT WOS:000165268900030 ER PT J AU Reidys, CM AF Reidys, CM TI Random subgraphs of Cayley graphs over p-groups SO EUROPEAN JOURNAL OF COMBINATORICS LA English DT Article ID CUBE AB The subject of this paper is the size of the largest component in random subgraphs of Cayley graphs, X-n, taken over a class of p-groups, G(n).G(n) consists of p-groups, G(n), with the following properties: (i) G(n)/Phi (G(n)) congruent to F-p(n). where Phi (G(n)) is the Frattini subgroup and (ii) \G(n)\ less than or equal to n(Kn), where K is some positive constant. We consider Cayley graphs X-n = Gamma (G(n), S-n'), where S-n' = S-n boolean OR S-n(-1), and S-n is a minimal G(n)-generating set. By selecting G(n)-elements with the independent probability lambda (n) we induce random subgraphs of X-n. Our main result is, that there exists a positive constant c > 0 such that for lambda (n) = c ln(\S-n'\)/\S-n'\ the largest component of random induced subgraphs of X-n contains almost all vertices. (C) 2000 Academic Press. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Reidys, CM (reprint author), Univ Calif Los Alamos Natl Lab, TSA-2,Mail Stop M977, Los Alamos, NM 87545 USA. NR 16 TC 0 Z9 0 U1 0 U2 0 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0195-6698 J9 EUR J COMBIN JI Eur. J. Comb. PD NOV PY 2000 VL 21 IS 8 BP 1057 EP 1066 DI 10.1006/eujc.2000.0421 PG 10 WC Mathematics SC Mathematics GA 376DL UT WOS:000165442900008 ER PT J AU Degtyarenko, PV Kossov, MV Wellisch, HP AF Degtyarenko, PV Kossov, MV Wellisch, HP TI Chiral invariant phase space event generator - II. Nuclear pion capture at rest and photonuclear reactions below the Delta(3,3) resonance. SO EUROPEAN PHYSICAL JOURNAL A LA English DT Article ID ABSORPTION AB An event generator based on the CHIPS model is implemented in the GEANT4 simulation toolkit. Nuclear fragment production in the process of pion capture on nuclei is used to tune the parameters of the CHIPS model describing clusterization of nucleons in nuclei. The spectra of nucleons and nuclear fragments in pion capture and in photonuclear reactions at 60 MeV are compared with experimental data. C1 Thomas Jefferson Natl Accelerator Facil, Newport News, VA USA. Inst Theoret & Expt Phys, Moscow 117259, Russia. CERN, CH-1211 Geneva, Switzerland. RP Degtyarenko, PV (reprint author), Thomas Jefferson Natl Accelerator Facil, Newport News, VA USA. NR 16 TC 25 Z9 25 U1 1 U2 3 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1434-6001 J9 EUR PHYS J A JI Eur. Phys. J. A PD NOV PY 2000 VL 9 IS 3 BP 411 EP 420 DI 10.1007/s100500070025 PG 10 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 398FX UT WOS:000166747200015 ER PT J AU Hessberger, FP Hofmann, S Ackermann, D Ninov, V Leino, M Saro, S Andreyev, A Lavrentev, A Popeko, AG Yeremin, AV AF Hessberger, FP Hofmann, S Ackermann, D Ninov, V Leino, M Saro, S Andreyev, A Lavrentev, A Popeko, AG Yeremin, AV TI Decay properties of neutron-deficient nuclei in the region Z = 86-92 (vol 8, pg 521, 2000) SO EUROPEAN PHYSICAL JOURNAL A LA English DT Correction C1 Gesell Schwerionenforsch GmbH, D-64220 Darmstadt, Germany. Univ Mainz, Inst Phys, D-55099 Mainz, Germany. EO Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Jyvaskyla, Dept Phys, FIN-40351 Jyvaskyla, Finland. Comenius Univ, Dept Phys Nucl, SK-84215 Bratislava, Slovakia. Joint Inst Nucl Res, Frank Lab Neutron Phys, Dubna 141980, Russia. Univ Liverpool, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England. Katholieke Univ Leuven, Inst Kern Stralingsfys, B-3001 Louvain, Belgium. Joint Inst Nucl Res, Flerov Lab Nucl React, Dubna 141980, Russia. RP Hessberger, FP (reprint author), Gesell Schwerionenforsch GmbH, D-64220 Darmstadt, Germany. NR 1 TC 17 Z9 17 U1 0 U2 1 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1434-6001 J9 EUR PHYS J A JI Eur. Phys. J. A PD NOV PY 2000 VL 9 IS 3 BP 433 EP 433 PG 1 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 398FX UT WOS:000166747200018 ER PT J AU Airapetian, A Akopov, N Akushevich, I Amarian, M Arrington, J Aschenauer, EC Avakian, H Avakian, R Avetissian, A Avetissian, E Bailey, P Bains, B Baumgarten, C Beckmann, M Belostotski, S Bernreuther, S Bianchi, N Bottcher, H Borissov, A Bouwhuis, M Brack, J Brauksiepe, S Braun, B Bruckner, W Brull, A Budz, P Bulten, HJ Capitani, GP Carter, P Chumney, P Cisbani, E Court, GR Dalpiaz, PF De Leo, R De Nardo, L De Sanctis, E De Schepper, D Devitsin, E Huberts, PKAD Di Nezza, P Djordjadze, V Duren, M Dvoredsky, A Elbakian, G Ely, J Fantoni, A Fechtchenko, A Ferro-Luzzi, M Fiedler, K Filippone, BW Fischer, H Fox, B Franz, J Frullani, S Garber, Y Garibaldi, F Garutti, E Gavrilov, G Gharibyan, V Golendukhin, A Graw, G Grebeniouk, O Green, PW Greeniaus, LG Gute, A Haeberli, W Hartig, M Hasch, D Heesbeen, D Heinsius, FH Henoch, M Hertenberger, R Hesselink, WHA Hoffmann-Rothe, P Hofman, G Holler, Y Holt, RJ Hommez, B Hoprich, W Iarygin, G Ihssen, H Iodice, M Izotov, A Jackson, HE Jgoun, A Kaiser, R Kanesaka, J Kinney, E Kisselev, A Kitching, P Kobayashi, H Koch, N Konigsmann, K Kolstein, M Kolster, H Korotkov, V Kotik, E Kozlov, V Krivokhijine, VG Kyle, G Lagamba, L Laziev, A Lenisa, P Lindemann, T Lorenzon, W Makins, NCR Martin, JW Marukyan, H Masoli, F McAndrew, M McIlhany, K McKeown, RD Meissner, F Menden, F Metz, A Meyners, N Mikloukho, O Miller, CA Milner, R Mitsyn, V Muccifora, V Mussa, R Nagaitsev, A Nappi, E Naryshkin, Y Nass, A Nowak, WD O'Neill, TG Openshaw, R Ouyang, J Owen, BR Pate, SF Potashov, S Potterveld, DH Rakness, G Redwine, R Reggiani, D Reolon, AR Ristinen, R Rith, K Robinson, D Ruh, M Ryckbosch, D Sakemi, Y Sevin, I Scarlett, C Schill, C Schmidt, F Schmitt, M Schnell, G Schuler, KP Schwind, A Seibert, J Shibata, TA Shin, T Shutov, V Simani, C Simon, A Sinram, K Steffens, E Steijger, JJM Stewart, J Stosslein, U Suetsugu, K Sutter, M Tallini, H Taroian, S Terkulov, A Tessarin, S Thomas, E Tipton, B Tytgat, M Urciuoli, GM van den Brand, JFJ van der Steenhoven, G van de Vyver, R van Hunen, JJ Vetterli, MC Vikhrov, V Vincter, MG Visser, J Volk, E Weiskopf, C Wendland, J Wilbert, J Wise, T Woller, K Yoneyama, S Zohrabian, H AF Airapetian, A Akopov, N Akushevich, I Amarian, M Arrington, J Aschenauer, EC Avakian, H Avakian, R Avetissian, A Avetissian, E Bailey, P Bains, B Baumgarten, C Beckmann, M Belostotski, S Bernreuther, S Bianchi, N Bottcher, H Borissov, A Bouwhuis, M Brack, J Brauksiepe, S Braun, B Bruckner, W Brull, A Budz, P Bulten, HJ Capitani, GP Carter, P Chumney, P Cisbani, E Court, GR Dalpiaz, PF De Leo, R De Nardo, L De Sanctis, E De Schepper, D Devitsin, E Huberts, PKAD Di Nezza, P Djordjadze, V Duren, M Dvoredsky, A Elbakian, G Ely, J Fantoni, A Fechtchenko, A Ferro-Luzzi, M Fiedler, K Filippone, BW Fischer, H Fox, B Franz, J Frullani, S Garber, Y Garibaldi, F Garutti, E Gavrilov, G Gharibyan, V Golendukhin, A Graw, G Grebeniouk, O Green, PW Greeniaus, LG Gute, A Haeberli, W Hartig, M Hasch, D Heesbeen, D Heinsius, FH Henoch, M Hertenberger, R Hesselink, WHA Hoffmann-Rothe, P Hofman, G Holler, Y Holt, RJ Hommez, B Hoprich, W Iarygin, G Ihssen, H Iodice, M Izotov, A Jackson, HE Jgoun, A Kaiser, R Kanesaka, J Kinney, E Kisselev, A Kitching, P Kobayashi, H Koch, N Konigsmann, K Kolstein, M Kolster, H Korotkov, V Kotik, E Kozlov, V Krivokhijine, VG Kyle, G Lagamba, L Laziev, A Lenisa, P Lindemann, T Lorenzon, W Makins, NCR Martin, JW Marukyan, H Masoli, F McAndrew, M McIlhany, K McKeown, RD Meissner, F Menden, F Metz, A Meyners, N Mikloukho, O Miller, CA Milner, R Mitsyn, V Muccifora, V Mussa, R Nagaitsev, A Nappi, E Naryshkin, Y Nass, A Nowak, WD O'Neill, TG Openshaw, R Ouyang, J Owen, BR Pate, SF Potashov, S Potterveld, DH Rakness, G Redwine, R Reggiani, D Reolon, AR Ristinen, R Rith, K Robinson, D Ruh, M Ryckbosch, D Sakemi, Y Sevin, I Scarlett, C Schill, C Schmidt, F Schmitt, M Schnell, G Schuler, KP Schwind, A Seibert, J Shibata, TA Shin, T Shutov, V Simani, C Simon, A Sinram, K Steffens, E Steijger, JJM Stewart, J Stosslein, U Suetsugu, K Sutter, M Tallini, H Taroian, S Terkulov, A Tessarin, S Thomas, E Tipton, B Tytgat, M Urciuoli, GM van den Brand, JFJ van der Steenhoven, G van de Vyver, R van Hunen, JJ Vetterli, MC Vikhrov, V Vincter, MG Visser, J Volk, E Weiskopf, C Wendland, J Wilbert, J Wise, T Woller, K Yoneyama, S Zohrabian, H CA HERMES Collaboration TI Exclusive leptoproduction of p(0) mesons from hydrogen at intermediate virtual photon energies SO EUROPEAN PHYSICAL JOURNAL C LA English DT Article ID NONFORWARD PARTON DISTRIBUTIONS; VECTOR-MESONS; DIFFRACTIVE PRODUCTION; PHI ELECTROPRODUCTION; COMPTON-SCATTERING; NUCLEON; RHO(0); HERA; PHYSICS; QCD AB Measurements of the cross section for exclusive virtual-photoproduction of rho (0) mesons from hydrogen are reported. The data were collected by the HERMES experiment using 27.5 GeV positrons incident on a hydrogen gas target in the HERA storage ring. The invariant mass W of the photon-nucleon system ranges from 4.0 to 6.0 GeV, while the negative squared four-momentum Q(2) Of the virtual photon varies from 0.7 to 5.0 GeV2. The present data together with roost of the previous data in the intermediate W-domain are well described by a model that infers the W-dependence of the cross section from the dependence on the Bjorken scaling variables of the unpolarized structure function for deep-inelastic scattering. In addition, a model calculation based on OR-Forward Parton Distributions gives a fairly good account of the longitudinal component of the rho (0) production cross section for Q(2) > 2 GeV2. C1 Yerevan Phys Inst, Yerevan 375036, Armenia. Univ Alberta, Dept Phys, Edmonton, AB T6G 2J1, Canada. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Ist Nazl Fis Nucl, Sez Bari, I-70124 Bari, Italy. CALTECH, WK Kellogg Radiat Lab, Pasadena, CA 91125 USA. Univ Colorado, Nucl Phys Lab, Boulder, CO 80309 USA. DESY, 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, Sez Ferrara, I-44100 Ferrara, Italy. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Univ Freiburg, Fak Phys, D-79104 Freiburg, Germany. Univ Ghent, Dept Subatom & Radiat Phys, B-9000 Ghent, Belgium. Max Planck Inst Kernphys, D-69029 Heidelberg, Germany. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Univ Liverpool, Dept Phys, Liverpool L69 7ZE, Merseyside, England. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. MIT, Nucl Sci Lab, Cambridge, MA 02139 USA. Univ Michigan, Randall Lab Phys, Ann Arbor, MI 48109 USA. PN Lebedev Phys Inst, Moscow 117942, Russia. Univ Munich, Sekt Phys, D-85748 Garching, Germany. New Mexico State Univ, Dept Phys, Las Cruces, NM 88003 USA. NIKHEF H, NL-1009 DB Amsterdam, Netherlands. Petersburg Nucl Phys Inst, Gatchina 188350, Russia. Ist Nazl Fis Nucl, Sez Sanita, I-00161 Rome, Italy. Ist Super Sanita, Phys Lab, I-00161 Rome, Italy. Simon Fraser Univ, Dept Phys, Burnaby, BC V5A 1S6, Canada. TRIUMF, Vancouver, BC V6T 2A3, Canada. Tokyo Inst Technol, Dept Phys, Tokyo 152, Japan. Free Univ Amsterdam, Dept Phys & Astron, NL-1081 HV Amsterdam, Netherlands. RP Yerevan Phys Inst, Yerevan 375036, Armenia. RI Arrington, John/D-1116-2012; 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 Arrington, John/0000-0002-0702-1328; Cisbani, Evaristo/0000-0002-6774-8473; Heinsius, Fritz-Herbert/0000-0002-9545-5117 NR 39 TC 71 Z9 71 U1 1 U2 4 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 NOV PY 2000 VL 17 IS 3 BP 389 EP 398 DI 10.1007/s100520000483 PG 10 WC Physics, Particles & Fields SC Physics GA 376RP UT WOS:000165470800002 ER PT J AU Benayoun, M DelBuono, L O'Connell, HB AF Benayoun, M DelBuono, L O'Connell, HB TI VMD, the WZW Lagrangian and ChPT: The third mixing angle SO EUROPEAN PHYSICAL JOURNAL C LA English DT Article ID CHIRAL PERTURBATION-THEORY; HIDDEN LOCAL SYMMETRY; TRANSITION FORM-FACTORS; DYNAMICAL GAUGE BOSONS; RADIATIVE DECAYS; SU(3) BREAKING; VECTOR-MESONS; U(1) PROBLEM; ETA-GAMMA; PHYSICS AB We show that the Hidden Local Symmetry Model, supplemented with well-known procedures for breaking flavor SU(3) and nonet symmetry, provides all the information contained in the standard Chiral Perturbation Theory (ChPT) Lagrangian L-(0) + L-(1). This allows to rely on radiative decays of light mesons (VP gamma and P gamma gamma) in order to extract some numerical information of relevance to ChPT: a value for Lambda (1) = 0.20 +/- 0.04, a quark mass ratio of similar or equal to 21.2 +/- 2.4, and a negligible departure form the Gell-Mann-Okubo mass formula. The mixing angles are theta (8) = -20.40 degrees +/- 0.96 degrees and theta (0) = -0.05 degrees +/- 0.99 degrees. We also give the values of all decay constants. It is shown that the common mixing pattern with one mixing angle theta (P) is actually quite appropriate and algebraically related to the eta/eta' mixing pattern presently preferred by the ChPT community. For instance the traditional theta (P) is functionally related to the ChPT theta (8) and fulfills theta (P) similar or equal to theta (8)/2. The vanishing of theta (0), supported by all data on radiative decays, gives a novel relation between mixing angles and the violation of nonet symmetry in the pseudoscalar sector. Finally, it is shown that the interplay of nonet symmetry breaking through U(3) --> SU(3) x U(1) satisfies all requirements of the physics of radiative decays without any need for additional glueballs. C1 Univ Paris 06, LPNHE, Paris, France. Univ Paris 07, IN2P3, Paris, France. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Benayoun, M (reprint author), Univ Paris 06, LPNHE, Paris, France. OI O'Connell, Heath/0000-0002-1895-5310 NR 59 TC 28 Z9 29 U1 0 U2 2 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 NOV PY 2000 VL 17 IS 4 BP 593 EP 610 DI 10.1007/s100520000497 PG 18 WC Physics, Particles & Fields SC Physics GA 380FF UT WOS:000165688600004 ER PT J AU Schlatholter, T Newman, MW Niedermayr, TR Machicoane, GA McDonald, JW Schenkel, T Hoekstra, R Hamza, AV AF Schlatholter, T Newman, MW Niedermayr, TR Machicoane, GA McDonald, JW Schenkel, T Hoekstra, R Hamza, AV TI Hydrogenated carbon clusters produced by highly charged ion impact on solid C-84 SO EUROPEAN PHYSICAL JOURNAL D LA English DT Article ID FRAGMENTATION; SLOW; C-60; EMISSION; SURFACES; DISTRIBUTIONS; FULLERENE; SPECTRA AB The emission of small (hydrogenated) carbon cluster ions: CnHm+ (n = 2-22) upon highly charged Xeq+ (q = 20- 14) impact on C-84 surfaces is studied by means of time-of-flight secundary ion mass spectrometry. The respective stage of hydrogenation/protonation of a certain carbon cluster ion C-n(+) is a strong indication for its geometrical structure. From the cluster ion yield as a function of cluster size it can be concluded, that the hydrogenation takes place after the initial carbon cluster formation. The carbon clusters seem to be emitted as art entity in agreement with "equilibrium" and "shock wave" models. C1 Univ Groningen, KVI Atom Phys, NL-9747 AA Groningen, Netherlands. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Schlatholter, T (reprint author), Univ Groningen, KVI Atom Phys, Zernikelaan 25, NL-9747 AA Groningen, Netherlands. EM tschlat@kvi.nl RI Schlatholter, Thomas/A-3407-2011; Hoekstra, Ronnie/E-9279-2012 OI Schlatholter, Thomas/0000-0001-9923-172X; NR 27 TC 11 Z9 11 U1 0 U2 0 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1434-6060 J9 EUR PHYS J D JI Eur. Phys. J. D PD NOV PY 2000 VL 12 IS 2 BP 323 EP 327 DI 10.1007/s100530070028 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 370JJ UT WOS:000165119500015 ER PT J AU Horvath, A Berry, EA Huang, LS Maslov, DA AF Horvath, A Berry, EA Huang, LS Maslov, DA TI Leishmania tarentolae: A parallel isolation of cytochrome bc(1) and cytochrome c oxidase SO EXPERIMENTAL PARASITOLOGY LA English DT Article DE cytochrome c oxidase; phenylmethylsulphonyl fluoride; diethylaminoethyl; bicinchoninic acid; Leishmania tarentolae; cytochrome c oxidase; cytochrome bc(1); kinetoplast; trypanosomatid ID TRYPANOSOMATID CRITHIDIA-FASCICULATA; RESPIRATORY-CHAIN; MITOCHONDRIA; PURIFICATION; COMPLEXES AB A rapid and simple method which allowed for a parallel isolation of cytochrome c reductase (cytochrome bell and cytochrome c oxidase from kinetoplast-mitochondria of Leishmania tarentolae was developed. The method involved the lysis of kinetoplasts with dodecyl maltoside in the presence of 260 mM NaCl, followed by purification of bc(1) complexes on DEAE-sepharose CL-6B. The oxidase which was found in the flow-through fractions of the first chromatographic step was diluted and then repurified on a similar DEAE-sepharose column. The investigated properties of the isolated cytochrome c oxidase and reductase, such as their absolute and difference spectrum absorption maxima, heme content, specific activity, and subunit composition, confirm the usefulness of this method for obtaining highly active preparations of the enzymes. (C) 2000 Academic Press. C1 Univ Calif Riverside, Dept Biol, Riverside, CA 92521 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA. RP Maslov, DA (reprint author), Univ Calif Riverside, Dept Biol, Riverside, CA 92521 USA. RI Horvath, Anton/I-3626-2014 FU NIAID NIH HHS [AI40634]; NIDDK NIH HHS [DK44842] NR 19 TC 18 Z9 18 U1 0 U2 2 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0014-4894 J9 EXP PARASITOL JI Exp. Parasitol. PD NOV PY 2000 VL 96 IS 3 BP 160 EP 167 DI 10.1006/expr.2000.4564 PG 8 WC Parasitology SC Parasitology GA 389XT UT WOS:000166264500005 PM 11162366 ER PT J AU Moser, KW Kutter, EC Georgiadis, IG Buckius, RO Morris, HD Torczynski, JR AF Moser, KW Kutter, EC Georgiadis, IG Buckius, RO Morris, HD Torczynski, JR TI Velocity measurements of flow through a step stenosis using Magnetic Resonance Imaging SO EXPERIMENTS IN FLUIDS LA English DT Article ID POROUS-MEDIA; PHASE; ACCELERATION AB Magnetic resonance imaging (MRI) is a versatile noninvasive tool for achieving full-field quantitative visualization of complex fluid flows. The MRI signal results from the interaction of radio-frequency (RF) pulses with nuclear spins exposed to a strong static magnetic field. The two main techniques of MRI velocimetry are time-of-flight and phase contrast techniques. Time-of- flight techniques involve tagging and tracking a material volume of fluid, whereas phase contrast techniques use magnetic field gradients to encode velocity information into the phase of the MRI signal. In this study, both techniques are used to probe the pressure-driven steady flow of water in a pipe with a step stenosis. The velocity measurements were then compared with computational results obtained using the FIDAP software package. The experiments show that the phase contrast method gives more accurate results, with 90% of the measurements within 10% of the local computational fluid dynamics (CFD) velocity predictions at Re = 100 and 94% of the measurements within 10% of the local CFD predictions at Re = 258. Although the time-of-flight experiments were not as accurate, they provide a good qualitative image of the flow field. Sources of the discrepancies between the MRI data and the CFD results are also discussed, including acceleration and spin flow-through artifacts. C1 Univ Illinois, Dept Mech & Ind Engn, Lab Quantitat Visualizat Energet, Urbana, IL 61801 USA. Univ Illinois, Biomed Magnet Resonance Lab, Urbana, IL 61801 USA. Sandia Natl Labs, Engn Sci Ctr, Albuquerque, NM 87185 USA. RP Georgiadis, IG (reprint author), Univ Illinois, Dept Mech & Ind Engn, Lab Quantitat Visualizat Energet, 1206 W Green St, Urbana, IL 61801 USA. NR 24 TC 27 Z9 27 U1 0 U2 0 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0723-4864 J9 EXP FLUIDS JI Exp. Fluids PD NOV PY 2000 VL 29 IS 5 BP 438 EP 447 DI 10.1007/s003480000110 PG 10 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA 376QX UT WOS:000165469200004 ER PT J AU Wang, JA Liu, KC McCabe, DE David, SA AF Wang, JA Liu, KC McCabe, DE David, SA TI Using torsional bar testing to determine fracture toughness SO FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES LA English DT Article DE fracture toughness; mixed mode fracture; size effect; spiral notch test; torsion bar testing ID QUARTER-POINT ELEMENTS; CRACK-TIP ELEMENTS; T-STRESS AB A new method to determine fracture toughness K-IC of materials is introduced. A round-rod specimen having a V-grooved spiral line with a 45 degrees pitch is tested under pure torsion. An equibiaxial tensile/compressive stress state is effectively created to simulate conventional test methods using a compact-type specimen with a thickness equivalent to the full length of the spiral line. K-IC values are estimated from the fracture load and crack length with the aid of a three-dimensional finite element analysis. K-IC of 7475-T7351 aluminium is estimated to be 51.3 MPa rootm, which is higher than the vendor's value in the TL orientation by similar to0.8% and higher than 0.5T compact tension (CT) value by 6%; A302B steel yields 54.9 MPa rootm being higher than CT test value by similar to2%. Good agreement between the K-IC values obtained by different methods indicates the proposed method is sound and reliable. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37830 USA. RP Wang, JA (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37830 USA. OI Wang, Jy-An/0000-0003-2402-3832 NR 17 TC 5 Z9 5 U1 0 U2 4 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 8756-758X J9 FATIGUE FRACT ENG M JI Fatigue Fract. Eng. Mater. Struct. PD NOV PY 2000 VL 23 IS 11 BP 917 EP 927 DI 10.1046/j.1460-2695.2000.00352.x PG 11 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 394LV UT WOS:000166526300004 ER PT J AU Scaffidi-Argentina, F Longhurst, GR Shestakov, V Kawamura, H AF Scaffidi-Argentina, F Longhurst, GR Shestakov, V Kawamura, H TI Beryllium R&D for fusion applications SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE beryllium; fusion applications; plasma-facing material ID NEUTRON-IRRADIATED BERYLLIUM; ELEVATED-TEMPERATURES; CHEMICAL INTERACTIONS; DEUTERIUM RETENTION; COMPREHENSIVE MODEL; TRITIUM RELEASE; ISX-B; CARBON; CODEPOSITION; HYDROGEN AB Beryllium is one of the primary candidates as both plasma-facing material (PFM) and neutron multiplier in the next-step fusion reactors. Both sintered-product blocks and pebbles are considered in fusion reactor designs. Beryllium evaporated on carbon tiles has also been used in Joint European Torus (JET) and may be considered for other designs. Future efforts are directed toward the pebble form of beryllium. Research and evaluations of data are underway to determine the most attractive material processing approaches in terms of fabrication cost and quality; technical issues associated with heat transfer; thermal, mechanical and irradiation stability; safety and tritium release. Beryllium plasma-facing components will require periodic repair or replacement, therefore disposal or recycling of activated and tritiated beryllinm will also be a concern. Beryllium as a component of the molten salt, Flibe is also being considered in novel approaches to the plasma-structure interface. This paper deals with the main issues related to the use of Be in a fusion reactor as both neutron multiplier and first wall material. These issues include potential reactions with steam during accidents and the health and environmental aspects of its use, reprocessing and reuse, or disposal. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Forschungszentrum Karlsruhe, IKET, D-76344 Eggenstein Leopoldshafen, Germany. Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. Sci Tech Ctr Controlled Thermonuclear Fus, Almaty 480012, Kazakhstan. Japan Atom Energy Res Inst, Ibaraki, Osaka, Japan. Forschungszentrum Karlsruhe, IKET, D-76021 Karlsruhe, Germany. RP Scaffidi-Argentina, F (reprint author), Forschungszentrum Karlsruhe, IKET, Hermann Von Helmotz Pl 1, D-76344 Eggenstein Leopoldshafen, Germany. EM francesco.scaffidi@iket.fzk.de NR 115 TC 12 Z9 15 U1 3 U2 10 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 NOV PY 2000 VL 51-52 BP 23 EP 41 DI 10.1016/S0920-3796(00)00312-4 PG 19 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GX UT WOS:000165996400003 ER PT J AU Zinkle, SJ Ghoniem, NM AF Zinkle, SJ Ghoniem, NM TI Operating temperature windows for fusion reactor structural materials SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE temperature windows; fusion energy applications; structural materials ID RESEARCH-AND-DEVELOPMENT; FERRITIC-MARTENSITIC STEELS; FRACTURE-TOUGHNESS; NEUTRON-IRRADIATION; VANADIUM ALLOYS; CORROSION BEHAVIOR; REFRACTORY-METALS; SILICON-CARBIDE; SIC/SIC COMPOSITES; TENSILE PROPERTIES AB A critical analysis is presented of the operating temperature windows for nine candidate fusion reactor structural materials: four reduced-activation structural materials (oxide-dispersion-strengthened and ferritic/martensitic steels containing 8-12%Cr, V-4Cr-4Ti, and SiC/SiC composites), copper-base alloys (CuNiBe), tantalum-base alloys (e.g. Ta-8W-2Hf), niobium alloys (Nb-1Zr), and molybdenum and tungsten alloys. The results are compared with the operating temperature limits for Type 316 austenitic stainless steel. Several factors define the allowable operating temperature window for structural alloys in a fusion reactor. The lower operating temperature limit in all body-centered cubic (BCC) and most face-centered cubic (FCC) alloys is determined by radiation embrittlement (decrease in fracture toughness), which is generally most pronounced for irradiation temperatures below similar to 0.3 T(M) where T(M) is the melting temperature. The lower operating temperature limit for SiC/SiC composites will likely be determined by radiation-induced thermal conductivity degradation, which becomes more pronounced in ceramics with decreasing temperature. The upper operating temperature limit of structural materials is determined by one of four factors, all of which become more pronounced with increasing exposure time: (1) thermal creep (grain boundary sliding or matrix diffusional creep); (2) high temperature He embrittlement of grain boundaries; (3) cavity swelling (particularly important for SiC and Cu alloys); or (4) coolant compatibility/corrosion issues. In many cases, the upper temperature limit will be determined by coolant corrosion/compatibility rather than by thermal creep or radiation effects. The compatibility of the structural materials with Li, Pb-Li, Sn-Li, He and Flibe (Li(2)BeF(4)) coolants is summarized. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. Univ Calif Los Angeles, Dept Aerosp & Mech Engn, Los Angeles, CA 90095 USA. RP Zinkle, SJ (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. EM zinklesj@ornl.gov1 RI Ghoniem, Nasr/A-9799-2008; OI Zinkle, Steven/0000-0003-2890-6915 NR 122 TC 248 Z9 248 U1 13 U2 135 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 NOV PY 2000 VL 51-52 BP 55 EP 71 DI 10.1016/S0920-3796(00)00320-3 PG 17 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GX UT WOS:000165996400005 ER PT J AU Klepikov, AK Romanenko, OG Chikhray, YV Tazhibaeva, IL Shestakov, VP Longhurst, GR AF Klepikov, AK Romanenko, OG Chikhray, YV Tazhibaeva, IL Shestakov, VP Longhurst, GR TI Hydrogen release from irradiated vanadium alloy V-4Cr-4Ti SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE hydrogen retention and release; irradiated materials; vanadium alloys AB The present work is an attempt to obtain data concerning the influence of neutron and gamma irradiation upon hydrogen retention in V-4Cr-4Ti vanadium alloy. The experiments on in-pile loading of vanadium alloy specimens at the neutron flux density 10(14) n/cm(2) s, hydrogen pressure of 80 Pa, and temperatures of 563, 613 and 773 K were carried out using the IVG.1M reactor of the Kazakhstan National Nuclear Center. A preliminary set of loading/degassing experiments with non-irradiated material has been carried out to obtain data on hydrogen interaction with vanadium alloy. The, data presented in this work are related both to non-irradiated and irradiated samples. (C) Published by Elsevier Science B.V. C1 Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. Kanakh State Univ, SRIETP, Almaty 480012, Kazakhstan. RP Longhurst, GR (reprint author), Idaho Natl Engn & Environm Lab, POB 1625, Idaho Falls, ID 83415 USA. EM klepikov@ietp.alma-ata.su; gxl@inel.gov RI Chikhray, Yevgeni/A-7226-2012 OI Chikhray, Yevgeni/0000-0001-6623-4596 NR 16 TC 12 Z9 12 U1 0 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 NOV PY 2000 VL 51-52 BP 127 EP 133 DI 10.1016/S0920-3796(00)00305-7 PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GX UT WOS:000165996400015 ER PT J AU Natesan, K Uz, M AF Natesan, K Uz, M TI Oxidation performance of V-Cr-Ti alloys SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE oxidation kinetics; parabolic kinetics; V alloys; hardness profiles AB Vanadium-base alloys are being considered as candidates for the first wall in advanced V-Li blanket concepts in fusion reactor systems. However, a primary deterrent to the use of these alloys at elevated temperatures is their relatively high affinity for interstitial impurities, i.e. O, N, H, and C. We conducted a systematic study to determine the effects of time, temperature, and oxygen partial pressure (p(O2)) in the exposure environment on O uptake, scaling kinetics, and scale microstructure in V-(4-5) wt.% Cr-(4-5) wt.% Ti alloys. Oxidation experiments were conducted on the alloys at P(O2) in the range of 5 x 10(-6)-760 torr (6.6 x 10(-4)-1 x 10(5) Pa) at several temperatures in the range of 350-700 degreesC. Models that describe the oxidation kinetics, oxide type and thickness, alloy grain size, and depth of O diffusion in the substrate of the two alloys were determined and compared. Weight change data were correlated with time by a parabolic relationship. The parabolic rate constant was calculated for various exposure conditions and the temperature dependence of the constant was described by an Arrhenius relationship. The results showed that the activation energy for the oxidation process is fairly constant at p(O2) levels in the range of 5 x 10(-6)-0.1 torr. The activation energy calculated from data obtained in the air tests was significantly lower, whereas that obtained in pure-O tests (at 760 torr) was substantially higher than the energy obtained under low-p(O2) conditions. The oxide VO(2) was the predominant phase that formed in both alloys when exposed to p(O2) levels of 6.6 x 10(-4) to 0.1 torr. V(2)O(5) was the primary phase in specimens exposed to air and to pure O, at 760 torr. The implications of the increased O concentration are increased strength and decreased ductility of the alloy. However, the strength of the alloy was not a strong function of the O concentration of the ahoy, but an increase in O concentration did cause a substantial decrease in ductility. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Energy Technol, Fus Power Program, Argonne, IL 60439 USA. RP Natesan, K (reprint author), Argonne Natl Lab, Div Energy Technol, Fus Power Program, 9700 S Cass Ave,Bldg 212, Argonne, IL 60439 USA. EM natesan@anl.gov NR 4 TC 14 Z9 16 U1 0 U2 5 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 NOV PY 2000 VL 51-52 BP 145 EP 152 DI 10.1016/S0920-3796(00)00308-2 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GX UT WOS:000165996400017 ER PT J AU Shikama, T Yamamoto, S Snider, R Fukao, M Nishitani, T Young, K Kasai, S Narui, M Broesch, J Matsuo, H Sagawa, T AF Shikama, T Yamamoto, S Snider, R Fukao, M Nishitani, T Young, K Kasai, S Narui, M Broesch, J Matsuo, H Sagawa, T TI Fission-reactor-radiation-tests of MI-cables and magnetic coils for fusion burning plasma diagnostics SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE magnetic probe; International Thermonuclear Experimental Reactor (ITER); plasma diagnostics; fission reactor radiation; in-situ measurement; international collaboration AB Magnetic probes for plasma diagnostics in the International Thermonuclear Experimental Reactor (ITER) were developed and tested in a fission reactor, the Japan Materials Testing Reactor. Performance of coils made of mineral insulating cables could be analyzed by a proposed equivalent electrical circuit but were disturbed by electrical drift, presumably caused by a phenomenon called radiation induced electromotive force. However, results were promising and development of an ITER-relevant magnetic probe is within view. (C) Published by Elsevier Science B.V. All rights reserved. C1 Tohoku Univ, Inst Mat Res, Oarai Branch, Oarai, Ibaraki 3111313, Japan. ITER JWS Garching, D-85748 Garching, Germany. Gen Atom Co, San Diego, CA 92186 USA. Shizuoka Univ, Hamamatsu, Shizuoka 4328561, Japan. JAERI Naka, Naka, Ibaraki 3110913, Japan. Princeton Univ, PPPL, Princeton, NJ 08540 USA. Japan Atom Energy Res Inst, Oarai, Ibaraki 3111394, Japan. RP Shikama, T (reprint author), Tohoku Univ, Inst Mat Res, Oarai Branch, Oarai, Ibaraki 3111313, Japan. EM shikama@imr.tohoku.ac.jp RI Shikama, Tatsuo/C-3042-2011 NR 8 TC 12 Z9 12 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 NOV PY 2000 VL 51-52 BP 171 EP 177 DI 10.1016/S0920-3796(00)00315-X PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GX UT WOS:000165996400021 ER PT J AU Smith, DL Natesan, K Park, JH Reed, CB Mattas, RF AF Smith, DL Natesan, K Park, JH Reed, CB Mattas, RF TI Development of electrically insulating coatings on vanadium alloys for lithium-cooled blankets SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE vanadium alloys; magnetohydrodynamic pressure; lithium blanket; coatings; insulation AB The self-cooled lithium blanket concept with a vanadium structure offers a potential for high performance with attractive safety and environmental features. Based on blanket design studies, it became apparent that electrically insulating duct walls would be required to reduce the magnetohydrodynamic (MHD) pressure drop for liquid metal-cooled blankets for high magnetic field fusion devices. As a result, development of insulator coatings was recommended as the most appropriate approach for resolving this issue. Oxides such as CaO, Y(2)O(3), BeO. MgO, MgAl(2)O(4), and Y(3)Al(2)O(12) and nitrides such as AIN, BN and Si(3)N(2) were initially considered potential candidate coating materials. Based on results of scoping studies, CaO and AlN have been selected as primary candidates for further development. Progress on the development of CaO and AlN coatings, including in-situ formation and electrical properties measurements, are summarized in this paper. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Fus Power Program, Argonne, IL 60439 USA. RP Smith, DL (reprint author), Argonne Natl Lab, Fus Power Program, 9700 S Cass Ave, Argonne, IL 60439 USA. EM dalesmith@anl.gov NR 14 TC 24 Z9 24 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 NOV PY 2000 VL 51-52 BP 185 EP 192 DI 10.1016/S0920-3796(00)00317-3 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GX UT WOS:000165996400023 ER PT J AU Gulden, W Cook, I Marbach, G Raeder, J Petti, D Seki, Y AF Gulden, W Cook, I Marbach, G Raeder, J Petti, D Seki, Y TI An update of safety and environmental issues for fusion SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE SEAFP; SEAL; ARIES-RS; DREAM; fusion; safety; environmental impact ID REACTORS AB To characterise and quantify the safety and environmental aspects of fusion power plants, studies using the tokamak concept have been undertaken within the European Fusion Programme under the names SEAFP and SEAL. The main results obtained up to early 1997 were reported at ISFNT-4. The newest findings will be presented in this paper. Comparison will be made with findings from fusion power plant studies performed outside the EU, i.e. ARIES-RS (US) and DREAM (JA). Important lessons learnt from the International Thermonuclear Experimental Reactor Engineering Design Activities (ITER EDA) will also be presented. Emphasis will be put on how the two leading success criteria 'no-evacuation of the public for any in-plant accident' and 'no radioactive waste burden for future generations' can be met and how these criteria fit with the fundamental safety objectives of the recently presented European utilities requirements for LWR nuclear power plants. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Max Planck Inst Plasmaphys, European Fus Dev Agreement Close Support Unit Gar, D-85748 Garching, Germany. UKAEA Euratom Fus Assoc, Abingdon OX14 3DB, Oxon, England. CEA, EURATOM Assoc, DER, SERSI, F-13108 St Paul Durance, France. Commiss European Communities, D-85748 Garching, Germany. Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. Japan Atom Energy Res Inst, Naka Fus Res Estab, Naka, Ibaraki 31101, Japan. RP Gulden, W (reprint author), Max Planck Inst Plasmaphys, European Fus Dev Agreement Close Support Unit Gar, Boltzmannstr 2, D-85748 Garching, Germany. NR 19 TC 2 Z9 2 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 NOV PY 2000 VL 51-52 BP 419 EP 427 DI 10.1016/S0920-3796(00)00288-X PG 9 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GX UT WOS:000165996400054 ER PT J AU Petti, DA McCarthy, KA Taylor, NP Forty, CBA Forrest, RA AF Petti, DA McCarthy, KA Taylor, NP Forty, CBA Forrest, RA TI Re-evaluation of the use of low activation materials in waste management strategies for fusion SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE tokamark; radiotoxicity; recycling AB The world fusion programs have had a long goal that fusion power stations should produce only low level waste and thus not pose a burden for the future generations. However, the environmental impact of waste material is determined not only by the level of activation, but also the total Volume of activated material. Since a tokamak power plant is large, the potential to generate a correspondingly large volume of activated material exists. The adoption of low activation materials, while important for reducing the radiotoxicity of the most active components, should be done as part of a strategy that also minimizes the volume of waste material that might be categorized as radioactive, even if lower in level. In this paper we examine different fusion blanket and shield designs in terms of their ability to limit the activation of the large vessel/ex-vessel components (e.g. vacuum vessel, magnets) and we identify the trends that allow improved in-vessel shielding to result in reduced vessel/ex-vessel activation. Recycling and clearance are options for reducing the volume of radioactive waste in a fusion power plant. Thus, the performance of typical fusion power plant designs with respect to recycling and clearance criteria are also assessed, to show the potential for improvement in waste volume reduction by careful selection of materials' combinations. We discuss the impact of these results on fusion waste strategies and on the development of fusion power in the future. (C) Published by Elsevier Science B.V. C1 Idaho Natl Engn & Environm Lab, Fus Safety Program, Idaho Falls, ID 83415 USA. UKAEA Euratom Fus Assoc, Culham Sci Ctr, Culham, England. RP Petti, DA (reprint author), Idaho Natl Engn & Environm Lab, Fus Safety Program, POB 1625, Idaho Falls, ID 83415 USA. NR 15 TC 15 Z9 15 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 NOV PY 2000 VL 51-52 BP 435 EP 444 DI 10.1016/S0920-3796(00)00229-5 PG 10 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GX UT WOS:000165996400056 ER PT J AU Carmack, WJ Anderl, RA Pawelko, RJ Smolik, GR McCarthy, KA AF Carmack, WJ Anderl, RA Pawelko, RJ Smolik, GR McCarthy, KA TI Characterization and analysis of dusts produced in three experimental tokamaks: TFTR, DIII-D, and Alcator C-Mod SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE dusts; tokamaks; TFTR; DIII-D; Alcator C-Mod AB Particulate, referred to as 'dust', produced during operation of tokamak systems can be a large source of activated material in a D-T fusion machine. Particulate less than 10 mum in size is easily mobilized both during an accident as well as during routine maintenance activities. We have collected and analyzed dust samples from three tokamaks to determine the potential contribution to accident source terms in future fusion power plants. We have obtained dust samples from Princeton Plasma Physics Laboratory's TFTR (prior to the final run period in 1997), from MIT's Alcator C-Mod (during March and April of 1998), and from General Atomics' DIII-D (August of 1998). This paper presents the results of our analyses for particle size distribution, specific surface area, and dust composition, including the tritium content of TFTR dust. (C) 2000 Published by Elsevier Science B.V. C1 Idaho Natl Engn & Environm Lab, Fus Safety Program, Idaho Falls, ID 83415 USA. RP Carmack, WJ (reprint author), Idaho Natl Engn & Environm Lab, Fus Safety Program, POB 1625, Idaho Falls, ID 83415 USA. EM wjc@inel.gov NR 16 TC 30 Z9 30 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 NOV PY 2000 VL 51-52 BP 477 EP 484 DI 10.1016/S0920-3796(00)00269-6 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GX UT WOS:000165996400062 ER PT J AU McCarthy, KA Petti, DA Moore, RL Merrill, BJ AF McCarthy, KA Petti, DA Moore, RL Merrill, BJ TI Safety issues associated with mobilized activation products in selected APEX designs SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE advanced power extraction; safety; mobilization; radiologically hazardous AB In the advanced power extraction (APEX) project, safety and environmental concerns considered up front, as designs evolve, so that the goal of safety and environmental attractiveness is realized. Since the neutron and surface heat loads are higher in APEX designs than those in conventional fusion designs, decay heat and activation are generally higher, presenting an increased challenge when justifying the safety case. Potential first wall materials that can function adequately under higher neutron and heat loads include materials such as tungsten and molybdenum. The activation products of both these materials are radiologically hazardous and mobilizable under accident conditions. We have examined a number of APEX concepts to determine the ability of the design to remove decay heat from the plasma-facing surface during a loss of coolant and air ingress event. In this paper, we concentrate on mobilization of first wall materials during ingress events, and provide guidance to enhance the safety characteristics of APEX designs that utilize tungsten and similar high heat load materials. (C) Published by Elsevier Science B.V. C1 Idaho Natl Lab, Nucl Engn Technol Dept, Fus Safety Program, Idaho Falls, ID 83415 USA. RP McCarthy, KA (reprint author), Idaho Natl Lab, Nucl Engn Technol Dept, Fus Safety Program, POB 1625, Idaho Falls, ID 83415 USA. EM km3@inel.gov NR 13 TC 2 Z9 2 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 NOV PY 2000 VL 51-52 BP 549 EP 554 DI 10.1016/S0920-3796(00)00217-9 PG 6 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GX UT WOS:000165996400071 ER PT J AU Merrill, BJ Moore, RL Polkinghorne, ST Petti, DA AF Merrill, BJ Moore, RL Polkinghorne, ST Petti, DA TI Modifications to the MELCOR code for application in fusion accident analyses SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE MELCOR; international thermonuclear experimental reactor; engineering design activity; loss-of-cooling accidents; loss-of-vacuum accidents ID SURFACES AB For the past several years, the Fusion Safety Program at the Idaho National Engineering and Environmental Laboratory (INEEL) has modified the MELCOR code in order to assess safety issues associated with loss-of-cooling accidents (LOCAs) and loss-of-vacuum accidents (LOVAs) in the international thermonuclear experimental reactor (ITER) engineering design activity (EDA). MELCOR is a thermal hydraulics computer code developed by the Sandia National Laboratory for analyzing severe accidents in fission power plants. This paper describes these modifications and the role they played in LOVA and LOCA analyses performed for the non-site specific safety report (NSSR) for the ITER EDA. (C) Published by Elsevier Science B.V. C1 Idaho Natl Engn & Environm Lab, Fus Safety Program, Idaho Falls, ID 83415 USA. RP Petti, DA (reprint author), Idaho Natl Engn & Environm Lab, Fus Safety Program, POB 1625, Idaho Falls, ID 83415 USA. NR 36 TC 29 Z9 29 U1 1 U2 8 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 NOV PY 2000 VL 51-52 BP 555 EP 563 DI 10.1016/S0920-3796(00)00220-9 PG 9 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GX UT WOS:000165996400072 ER PT J AU Pinna, T Cadwallader, LC AF Pinna, T Cadwallader, LC TI Component failure rate data base for fusion applications SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE component failures; database; probabilistic assessment AB Due to the small number and the innovative aspects of fusion devices, in general, not much information is available in the literature about availability and reliability of their components. To perform probabilistic safety assessment of fusion devices, analysts have to consider use of reliability data originating from different technological experiences. To set up ail the available information and create a dedicated data source on components typically used in fusion facilities, a specific database system has been developed. Data collection and data distribution activities have been established in the context of the International Energy Agency Agreement on the Environmental, Safety and Economic Aspects of Fusion Power (IEA ESE). This database development has been carried out to pursue the objective of creating a reference databank for the international fusion community. This paper briefly describes the database structure, the adopted generic component classification, and the fusion specific component breakdown. It also describes the procedure to gain consensus on data between interested IEA participants. (C) 2000 Elsevier Science B.V. All rights reserved. C1 CR Frascati, Ass Euratom, ENEA Fus, I-00044 Frascati, Rome, Italy. Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Pinna, T (reprint author), CR Frascati, Ass Euratom, ENEA Fus, Via E Fermi 27, I-00044 Frascati, Rome, Italy. EM pinna@frascati.enea.it RI Cadwallader, Lee/F-6933-2014 NR 3 TC 12 Z9 12 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 NOV PY 2000 VL 51-52 BP 579 EP 585 DI 10.1016/S0920-3796(00)00231-3 PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GX UT WOS:000165996400075 ER PT J AU Hassanein, A Konkashbaev, I AF Hassanein, A Konkashbaev, I TI Theory and models of material erosion and lifetime during plasma instabilities in a tokamak environment SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE plasma; erosion; materials; disruptions; vapour shielding; HEIGHTS ID DISRUPTION AB Surface and structural damage to plasma-facing components (PFCs) due to the frequent loss of plasma confinement remains a serious problem for the tokamak reactor concept. The deposited plasma energy causes significant surface erosion, possible structural failure and frequent plasma contamination. Surface damage consists of vaporization, spallation, and liquid splatter of metallic materials. Structural damage includes large temperature increases in structural materials and at the interfaces between surface coatings and structural members. To evaluate the lifetimes of plasma-facing materials and nearby components and to predict the Various forms of damage that they experience, comprehensive models (contained in the HEIGHTS computer simulation package) are developed, integrated self-consistently and enhanced. Splashing mechanisms, such as bubble boiling and various liquid magnetohydrodynamic instabilities and brittle destruction mechanisms of non-melting materials, are being examined. The design requirements and implications of plasma-facing and nearby components are discussed, along with recommendations to mitigate and reduce the effects of plasma instabilities on reactor components. (C) 2000 Published by Elsevier Science B.V. C1 Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. Troitsk Inst Innovat & Fus Res, Troitsk, Russia. RP Hassanein, A (reprint author), Argonne Natl Lab, Div Energy Technol, 9700 S Cass Ave,Bldg 207, Argonne, IL 60439 USA. NR 20 TC 5 Z9 5 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 NOV PY 2000 VL 51-52 BP 681 EP 694 DI 10.1016/S0920-3796(00)00245-3 PG 14 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GX UT WOS:000165996400088 ER PT J AU Rodig, M Akiba, M Chappuis, P Duwe, R Febvre, M Gervash, A Linke, J Litounovsky, N Suzuki, S Wiechers, B Youchison, DL AF Rodig, M Akiba, M Chappuis, P Duwe, R Febvre, M Gervash, A Linke, J Litounovsky, N Suzuki, S Wiechers, B Youchison, DL TI Comparison of electron beam test facilities for testing of high heat flux components SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE electron beam facilities; high heat flux components; mock-up temperatures AB In the last few years, electron beam facilities for the testing of high heat flux components have been erected in Europe, Japan, Russia and in the USA. In principle ail the facilities are comparable, but some machine parameters are quite different. These differences include electron beam operation (beam generation, beam diameter, sweeping mode), as well as the temperature measurement devices, calibration techniques and the definition of absorbed power densities. In order to assess the influence of these machine parameters and techniques on the results of high heat flux experiments, a round robin test has been performed in five facilities. In these tests, actively cooled CFC monoblock mock-ups were heated by electron beams using target power densities up to 15 MW/m(2). Mock-up temperatures and their distribution, measured by different methods (IR camera, pyrometer, thermocouples), have been used as criteria for comparison. The evaluation of data from the different facilities shows good agreement for identical target loading conditions. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Forschungszentrum Julich, EURATOM Assoc, D-52425 Julich, Germany. JAERI, Naka, Ibaraki, Japan. CEA, DRFC, F-13115 St Paul Les Durance, France. Framatome France, Ctr Tech, F-89100 Le Creusot, France. Efremov Inst, St Petersburg 189631, Russia. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Rodig, M (reprint author), Forschungszentrum Julich, EURATOM Assoc, Postfach 1913, D-52425 Julich, Germany. EM m.roedig@fz-juelich.de OI Youchison, Dennis/0000-0002-7366-1710 NR 12 TC 12 Z9 12 U1 1 U2 2 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 NOV PY 2000 VL 51-52 BP 715 EP 722 DI 10.1016/S0920-3796(00)00219-2 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GX UT WOS:000165996400091 ER PT J AU Itoh, T Akino, N Ebisawa, N Grisham, L Honda, A Hu, LQ Kawai, M Kazawa, M Kuriyama, M Kusaka, M Mogaki, K Nishitani, T Ohga, T Okumura, Y Oohara, H Ooshima, K Satoh, F Seki, H Tanai, Y Toyokawa, R Usui, K Watanabe, K Yamaguti, M Yamazaki, H Yamazaki, T AF Itoh, T Akino, N Ebisawa, N Grisham, L Honda, A Hu, LQ Kawai, M Kazawa, M Kuriyama, M Kusaka, M Mogaki, K Nishitani, T Ohga, T Okumura, Y Oohara, H Ooshima, K Satoh, F Seki, H Tanai, Y Toyokawa, R Usui, K Watanabe, K Yamaguti, M Yamazaki, H Yamazaki, T TI Beam performance of negative-ion based NBI system for JT-60 SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE beam; NBI system; JT-60 AB The negative-ion based NBI system (N-NBI) for JT-60 is being operated for a high energy neutral beam injection into the JT-60 plasma, in parallel with increasing the beam power. The estimation of the beam characteristics is very important for the enhancement and optimization of the beam power. The following four items have been used as the characterization of the beam: neutron yield from the beamline, beam divergence, heat load on the beamline components and beam profile on the armor plate in the tokamak Vacuum vessel. Since the beam power accelerated in the ion source is proportional to the neutron yield in the beamline components, the operation status of deuterium negative ion current can be monitored easily. The beam divergence estimated at the drift duct and ion dumps, and the heat load on the beamline components are used for the optimization of the ion source operation parameters and the evaluation of neutral beam injection power. The beam divergence measured at the drift duct is 4 mrad in the horizontal direction, 6 mrad in the vertical, which are in agreement with the design value of 5 mrad. The deposition profile on the armor plate is used for monitoring of the neutral beam profile. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Japan Atom Energy Res Inst, NBI Facil Div, Dept Fus Facil, Naka, Ibaraki 3110193, Japan. Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Itoh, T (reprint author), Japan Atom Energy Res Inst, NBI Facil Div, Dept Fus Facil, Naka, Ibaraki 3110193, Japan. EM titoh@naka.jaeri.go.jp NR 11 TC 13 Z9 14 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 NOV PY 2000 VL 51-52 BP 1039 EP 1047 DI 10.1016/S0920-3796(00)00438-5 PG 9 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GX UT WOS:000165996400134 ER PT J AU Logan, BG Meier, WR Moir, RW Abdou, M Peterson, PF Kulcinski, GL Tillack, MS Latkowski, JF Petti, D Schultz, KR Nobile, A AF Logan, BG Meier, WR Moir, RW Abdou, M Peterson, PF Kulcinski, GL Tillack, MS Latkowski, JF Petti, D Schultz, KR Nobile, A TI Progress and critical issues for IFE blanket and chamber research SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE inertial fusion energy; diode-pumped solid-state lasers; chamber research ID INERTIAL FUSION ENERGY AB Research has been initiated in the U.S. Virtual Laboratory for Technology on IFE chamber and target technologies. The critical issues, and the approaches taken to address these issues, are discussed. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Los Angeles, Dept Mech & Aerosp Engn, Los Angeles, CA USA. Univ Calif Berkeley, Dept Nucl Engn, Berkeley, CA 94720 USA. Univ Wisconsin, Madison, WI USA. Univ Calif San Diego, San Diego, CA 92103 USA. Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83401 USA. Gen Atom Co, San Diego, CA USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. RP Logan, BG (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94550 USA. EM loganl@llnl.gov NR 6 TC 0 Z9 0 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 NOV PY 2000 VL 51-52 BP 1095 EP 1101 DI 10.1016/S0920-3796(00)00221-0 PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GX UT WOS:000165996400141 ER PT J AU Latkowski, JF Cullen, DE Sanz, J AF Latkowski, JF Cullen, DE Sanz, J TI Evaluation of HYLIFE-II and Sombrero using 175-and 566-group neutron transport and activation cross sections SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE multigroup; activation; neutron transport AB Recent modifications to the TART Monte Carlo neutron and photon transport code allow enable calculation of 566-group neutron spectra. This expanded group structure represents a significant improvement over the 50- and 175-group structures that have been previously available. To support use of this new capability, neutron activation cross-section libraries have been created in the 175- and 566-group structures starting from the FENDL/A-2.0 pointwise data. Neutron spectra have been calculated for the first walls of the HYLIFE-II and Sombrero inertial fusion energy power plant designs and have been used in subsequent neutron activation calculations. The results obtained using the two different group structures are compared with each other as well as to those obtained using a 175-group version of the EAF3.1 activation cross-section library. (C) Published by Elsevier Science B.V. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Nacl Educ Distancia, Dept Ingn Energet, Escuela Tecn Super Ingn Ind, E-28040 Madrid, Spain. Int Fus Nucl, Madrid, Spain. RP Latkowski, JF (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,Mailstop L-446, Livermore, CA 94550 USA. EM latkowskil@llnl.gov 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 NOV PY 2000 VL 51-52 BP 1115 EP 1120 DI 10.1016/S0920-3796(00)00218-0 PG 6 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GX UT WOS:000165996400144 ER PT J AU Moir, RW AF Moir, RW TI Grazing incidence liquid metal mirrors (GILMM) for radiation hardened final optics for laser inertial fusion energy power plants SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE grazing incidence liquid metal mirrors; inertial fusion energy; Reynolds number AB A thin film of liquid metal is suggested as a grazing incident mirror for robust final optics in a laser inertial fusion energy (IFE) power plant. The amount of laser light the grazing incidence liquid metal mirror (GILMM) can withstand, called the damage limit is limited by the surface disturbances initiated by rapid laser heating. For 0.35-mum light, the damage limit for a sodium film 85 degrees from normal is calculated to be 57 J/cm(2) normal to the beam for a 20 ns pulse and 1.3 J/cm(2) for a 10-ps pulse (2 and 90 m(2) of mirror area per 100 kJ of laser energy at 20 ns and 10 ps, respectively). Feasibility relies on keeping the liquid surface flat to the required accuracy by a combination of polished substrate, adaptive (deformable) optics, surface tension and low Reynolds number, laminar flow in the film. The film's substrate must be polished to +/- 0.015 mum. Then surface tension keeps the surface smooth over short distances (< 10 mm) and low Reynolds number laminar flow keeps the surface smooth (disturbances less than +/- 0.01 m) over long distances (> 10 mm). Adaptive optics techniques keep the substrate flat to within +/- 0.06 mum over 100-mm distance and +/- 0.6 mum over 1000 mm distances, even after 30 years of cumulative damage via neutron irradiation. The mirror can stand the X-ray pulse when located 30 m away from the microexplosions of nominal yield of 400 MJ (50 MJ of X-rays) when Li is used, but for higher atomic number liquids like Na there may be a significant rise in temperature, forcing the use of other X-ray attenuation methods such as attenuation by xenon gas. The GILMM should be applicable to both direct and indirect drive and pulse lengths appropriate to slow compression (similar to 20 ns) or fast ignition (similar to 10 ps). For direct-drive laser beams near the poles (70 degrees, where 90 degrees is vertical), stable thin films become more challenging. Proof of the concept experiments are needed to verify the predicted damage limit and required smoothness. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Moir, RW (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94551 USA. EM moir@llnl.gov NR 11 TC 7 Z9 7 U1 0 U2 2 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 NOV PY 2000 VL 51-52 BP 1121 EP 1128 DI 10.1016/S0920-3796(00)00224-6 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GX UT WOS:000165996400145 ER PT J AU Sanz, J Yuste, P Reyes, S Latkowski, JF AF Sanz, J Yuste, P Reyes, S Latkowski, JF TI Efficient modeling for pulsed activation in inertial fusion energy reactors SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY ID INTERMITTENT ACTIVATION; NEUTRON-ACTIVATION; IRRADIATION; EXTRACTION; CODE AB First structural wall material (FSW) materials in inertial fusion energy (IFE) power reactors will be irradiated under typical repetition rates of 1-10 Hz, for an operation time as long as the total reactor lifetime. The main objective of the present work is to determine whether a continuous-pulsed (CP) approach can be an efficient method in modeling the pulsed activation process for operating conditions of FSW materials. The accuracy and practicability of this method was investigated both analytically and (for reaction/decay chains of two and three nuclides) by computational simulation. It was found that CP modeling is an accurate and practical method for calculating the neutron-activation of FSW materials. Its use is recommended instead of the equivalent steady-state method or the exact pulsed modeling. Moreover, the applicability of this method to components of an IFE power plant subject to repetition rates lower than those of the FSW is still being studied. The analytical investigation was performed for 0.05 Hz, which could be typical for the coolant. Conclusions seem to be similar to those obtained for the FSW. However, further future work is needed for a final answer. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Nacl Educ Distancia, ETS Ingn Ind, Dept Ingn Energet, E-28040 Madrid, Spain. Inst Fus Nucl, E-28040 Madrid, Spain. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Sanz, J (reprint author), Univ Nacl Educ Distancia, ETS Ingn Ind, Dept Ingn Energet, C Ciudad Univ S-N, E-28040 Madrid, Spain. EM jsanz@denim.upm.es NR 17 TC 1 Z9 1 U1 0 U2 2 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 NOV PY 2000 VL 51-52 BP 1129 EP 1135 DI 10.1016/S0920-3796(00)00441-5 PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GX UT WOS:000165996400146 ER PT J AU Sawan, ME Peterson, RR Yu, S AF Sawan, ME Peterson, RR Yu, S TI Shielding analysis for a heavy ion beam chamber with plasma channels for ion transport SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE plasma channels; ion; HYLIFE-II ID FUSION AB Neutronics analysis has been performed to assess the shielding requirements for the insulators and final focusing magnets in a modified HYLIFE-II target chamber that utilizes pre-formed plasma channels for heavy ion beam transport. Using 65-cm-thick Flibe jet assemblies provides adequate shielding for the electrical insulator units. Additional shielding is needed in front of the final focusing superconducting quadrupole magnets. A shield with a thickness varying between 45 and 90 cm needs to be provided in front of the quadrupole unit. The final laser mirrors located along the channel axis are in the direct line-of-sight of source neutrons. Neutronics calculations were performed to determine the constraints on the placement of these mirrors to be lifetime components. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Wisconsin, Fus Technol Inst, Madison, WI 53706 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Sawan, ME (reprint author), Univ Wisconsin, Fus Technol Inst, Madison, WI 53706 USA. NR 10 TC 2 Z9 2 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 NOV PY 2000 VL 51-52 BP 1137 EP 1142 DI 10.1016/S0920-3796(00)00227-1 PG 6 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GX UT WOS:000165996400147 ER PT J AU Majumdar, S AF Majumdar, S TI Structural design criteria for high heat flux components SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE international thermonuclear experimental reactor; structural design criteria; high heat flux components AB The high temperature design rules of the international thermonuclear experimental reactor (ITER) structural design criteria (ISDC) are applied to first wall designs with high heat flux. The maximum coolant pressure and surface heat flux capabilities are shown to be determined not only by the mechanical properties of the first wall material but also by the details of the blanket-design. In a high power density self-cooled lithium blanket, the maximum primary stress in the first wall is controlled by many of the geometrical parameters of the blanket, such as, first wall span, first wall curvature, first wall thickness, side wall thickness, and second wall thickness. Also, the creep-ratcheting lifetime of the first wall is controlled by many of the same geometrical parameters as well as the coolant temperature. According to most high temperature design codes, the time-dependent primary membrane stress allowable are based on the average temperature (ignoring thermal stress). Such a procedure may sometimes be unconservative, particularly for embrittled first walls with large temperature gradients. The effect of secondary (thermal) stresses on the accumulation of creep deformation is illustrated with a vanadium-alloy, hat plate first-wall design. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Fus Power Program, Argonne, IL 60439 USA. RP Majumdar, S (reprint author), Argonne Natl Lab, Fus Power Program, 9700 S Cass Ave, Argonne, IL 60439 USA. EM majumdar@anl.gov NR 7 TC 3 Z9 4 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 NOV PY 2000 VL 49-50 BP 119 EP 126 DI 10.1016/S0920-3796(00)00379-3 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GW UT WOS:000165996300016 ER PT J AU Mattas, RF Allain, JP Bastasz, R Brooks, JN Evans, T Hassanein, A Luckhardt, S McCarthy, K Mioduszewski, P Maingi, R Mogahed, E Moir, R Molokov, S Morely, N Nygren, R Rognlien, T Reed, C Ruzic, D Sviatoslavsky, I Sze, D Tillack, M Ulrickson, M Wade, PM Wooley, R Wong, C AF Mattas, RF Allain, JP Bastasz, R Brooks, JN Evans, T Hassanein, A Luckhardt, S McCarthy, K Mioduszewski, P Maingi, R Mogahed, E Moir, R Molokov, S Morely, N Nygren, R Rognlien, T Reed, C Ruzic, D Sviatoslavsky, I Sze, D Tillack, M Ulrickson, M Wade, PM Wooley, R Wong, C TI ALPS - advanced limiter-divertor plasma-facing systems SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE plasma; advanced limiter-divertor plasma-facing systems; tokamak ID INSTABILITIES; DISRUPTION; MODELS AB The advanced limiter-divertor plasma-facing systems (ALPS) program was initiated in order to evaluate the potential for improved performance and lifetime for plasma-facing systems. The main goal of the program is to demonstrate the advantages of advanced limiter/divertor systems over conventional systems in terms of power density capability, component lifetime, and power conversion efficiency, while providing for safe operation and minimizing impurity concerns for the plasma. Most of the work to date has been applied to free surface liquids. A multi-disciplinary team from several institutions has been organized to address the key issues associated with these systems. The main performance goals for advanced limiters and diverters are a peak heat flux of > 50 MW/m(2), elimination of a lifetime limit for erosion, and the ability to extract useful heat at high power conversion efficiency (similar to 40%). The evaluation of various options is being conducted through a combination of laboratory experiments, modeling of key processes, and conceptual design studies. The current emphasis for the work is on the effects of free surface liquids on plasma edge performance. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Wisconsin, Madison, WI 53706 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Coventry Univ, Coventry, W Midlands, England. Univ Calif Los Angeles, Los Angeles, CA 90095 USA. Univ Illinois, Nucl Engn Lab 214, Urbana, IL 61801 USA. Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. Gen Atom Co, San Diego, CA 92186 USA. RP Mattas, RF (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. OI Allain, Jean Paul/0000-0003-1348-262X; Molokov, Sergei/0000-0002-8633-345X NR 13 TC 39 Z9 39 U1 2 U2 8 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 NOV PY 2000 VL 49-50 BP 127 EP 134 DI 10.1016/S0920-3796(00)00385-9 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GW UT WOS:000165996300017 ER PT J AU Litunovsky, VN Kuznetsov, VE Lyublin, BV Ovchinnikov, IB Titov, VA Hassanein, A AF Litunovsky, VN Kuznetsov, VE Lyublin, BV Ovchinnikov, IB Titov, VA Hassanein, A TI Material response due to simulated plasma disruption loads SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE plasma disruptions; visible radiation flux; abnormal events; irradiation power AB The paper is focused on the problem of understanding key items of high heat flux plasma-material interaction during abnormal events: the net power flux that reached the target surface and the nature of the target erosion. As to first the results of direct measurements of visible radiation (Delta/lambda = 400-800 nm) flux on the target surface are presented. It is shown that visible radiation power flux emitted inside spectral range Delta lambda =400-700 nm can be characterised by the level of P(R) less than or equal to 1 GW/m(2) typical of experiments performed at the VIKA facility during irradiation power of P(irr) similar to 80 GW/m(2). It is also shown that the existence of the strong guide magnetic field of B similar to 2 T results in a change in the behaviour and microstructure of the (Al) metal melt layer. (C) 2000 Publishe by Elsevier Science B.V. C1 DV Efremov Sci Res Inst Electrophys Apparatus, Sci Tech Ctr Sinteza, St Petersburg 189631, Russia. Argonne Natl Lab, Argonne, IL 60439 USA. RP Litunovsky, VN (reprint author), DV Efremov Sci Res Inst Electrophys Apparatus, Sci Tech Ctr Sinteza, Sovetsky Pr 1, St Petersburg 189631, Russia. EM vlitun@niiefa.spb.su NR 5 TC 4 Z9 4 U1 0 U2 2 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 NOV PY 2000 VL 49-50 BP 249 EP 253 DI 10.1016/S0920-3796(00)00445-2 PG 5 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GW UT WOS:000165996300036 ER PT J AU Nygren, RE Youchison, DL Watson, RD O'Dell, S AF Nygren, RE Youchison, DL Watson, RD O'Dell, S TI High heat flux tests on heat sinks armored with tungsten rods SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE high heat flux tests; heat sinks; tungsten rods ID PLASMA-FACING COMPONENTS; FUSION DEVICES AB This paper presents the results of high heat flux tests at Sandia National Laboratories of mock-ups armored with W rods embedded in water-cooled copper-alloy heat sinks. The major result is the excellent performance of these mock-ups in thermal response tests at up to 30 MW/m(2) and in thermal cycling tests of 500 cycles (10 s on, 10 s off) at similar to 25 MW/m(2). Melting of rod tips and the subsequent 'self-repair' of a degraded thermal bond were seen. Issues for further development in both testing and manufacturing of the mock-ups were identified. Evaluation of the surface heat flux was found to be somewhat problematic and this issue is discussed. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Plasma Proc Inc, Huntington, AL USA. RP Nygren, RE (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. EM renygre@sandia.gov OI Youchison, Dennis/0000-0002-7366-1710 NR 17 TC 14 Z9 14 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 NOV PY 2000 VL 49-50 BP 303 EP 308 DI 10.1016/S0920-3796(00)00388-4 PG 6 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GW UT WOS:000165996300044 ER PT J AU Odegard, BC Cadden, CH Yang, NYC Watson, RD Youchison, DL AF Odegard, BC Cadden, CH Yang, NYC Watson, RD Youchison, DL TI Failure analysis of beryllium tile assemblies following high heat flux testing for the ITER program SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE beryllium tile assemblies; high heat flux testing; ITER program AB The following document describes the processing, testing and post-test analysis of two Be-Cu assemblies that have successfully met the heat load requirements for the first wall and dome sections for the International Thermonuclear Experimental Reactor (ITER) fusion reactor. Several different joint assemblies were evaluated in support of a manufacturing technology investigation aimed at diffusion bonding or brazing a beryllium armor tile to a copper alloy heat sink for fusion reactor applications. Judicious selection of materials and coatings for these assemblies was essential to eliminate or minimize interactions with the highly reactive beryllium armor material. A thin titanium layer was used as a diffusion barrier to isolate the copper heat sink from the beryllium armor. To reduce residual stresses produced by differences in the expansion coefficients between the beryllium and copper, a compliant layer of aluminum or aluminum-beryllium (AlBeMet-150) was used. Aluminum was chosen because it does not chemically react with, and exhibits limited solubility in, beryllium. Two bonding processes were used to produce the assemblies. The primary process was a diffusion bonding technique. In this case, undesirable metallurgical reactions were minimized by keeping the materials in a solid state throughout the fabrication cycle. The other process employed an aluminum-silicon layer as a brazing filler material. In both cases, a hot isostatic press (HIP) furnace was used in conjunction with vacuum-canned assemblies in order to minimize oxidation and provide sufficient pressure on the assemblies for full metal-to-metal contact and subsequent bonding. The two final assemblies were subjected to a suite of tests including: tensile tests and electron and optical metallography. Finally, high heat flux testing was conducted at the electron beam testing system (EBTS) at Sandia National Laboratories, NM. Here, test mockups were fabricated and subjected to normal heat loads to 10 MW/m(2) (3 Hz) and abnormal heat loads to 250 MJ/m(2) (0.5 s) to determine their performance under simulated fusion reactor conditions for first wall components. Both assemblies survived the normal heat loads with no visual damage. Optical and electron microscopy were used to evaluate the extent of the damage at the interfaces following the VDE simulations. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Sandia Natl Labs, Dept 8712, Livermore, CA 94551 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Odegard, BC (reprint author), Sandia Natl Labs, Dept 8712, POB 969, Livermore, CA 94551 USA. EM odegard@ca.sandia.gov OI Youchison, Dennis/0000-0002-7366-1710 NR 5 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0920-3796 J9 FUSION ENG DES JI Fusion Eng. Des. PD NOV PY 2000 VL 49-50 BP 309 EP 316 DI 10.1016/S0920-3796(00)00389-6 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GW UT WOS:000165996300045 ER PT J AU Ying, AY Morley, N Smolentsev, S Gulec, K Fogarty, P AF Ying, AY Morley, N Smolentsev, S Gulec, K Fogarty, P TI Free surface heat transfer and innovative designs for thin and thick liquid walls SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE surface heat transfer; liquid flows; liquid walls ID FLOW AB Design windows on free surface flows in the APEX (advanced power extraction) study are derived from the viewpoints of the free surface heat transfer, the adaptation of liquid flows to the topological constraints, and temperature requirements for plasma operation and power conversion efficiency. Within these constraints, the temperature of the free liquid surface facing the plasma is the most critical parameter governing the amount of liquid that evaporates into the plasma chamber. Present analyses show that a 2 cm or a 40 cm thick lithium layer can be established throughout the ARIES-RS reactor using a velocity of 10 m s(-1) while operating under the plasma compatible surface temperature. However, like solid metallic walls, the liquid lithium walls require the use of electrical insulators to overcome the MHD drag. As for Flibe free surface flows, the MHD effect caused by interaction with the mean flow is negligible, while a fairly uniform flow of 2 or 45 cm thick can be maintained throughout the reactor based on 3-D hydrodynamics calculations. However, being a low thermally conducting medium, the Flibe surface temperature highly depends on the extent of the turbulent convection. The heat transfer analyses based on the K-E model of the turbulence, including MHD effects and various boundary conditions, predict a range of temperatures that may be beyond the plasma compatible temperatures. If indeed the Flibe surface temperature is high relative to the plasma operation limit, further design adjustments will be required to accommodate this deficiency. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Angeles, Dept Mech & Aerosp Engn, Los Angeles, CA 90095 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Ying, AY (reprint author), Univ Calif Los Angeles, Dept Mech & Aerosp Engn, Los Angeles, CA 90095 USA. EM ying@fusion.ucla.edu NR 10 TC 8 Z9 8 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 NOV PY 2000 VL 49-50 BP 397 EP 406 DI 10.1016/S0920-3796(00)00242-8 PG 10 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GW UT WOS:000165996300058 ER PT J AU Youchison, DL North, MT Lindemuth, JE McDonald, JM Lutz, TJ AF Youchison, DL North, MT Lindemuth, JE McDonald, JM Lutz, TJ TI Thermal performance and flow instabilities in a multi-channel, helium-cooled, porous metal divertor module SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE helium; plasma facing components; divertor; porous metal; multi-channel; flow instabilities; thermal performance AB Pressurized helium is under consideration for cooling Langmuir probes and plasma facing components of next generation fusion experiments. Helium is non-corrosive, does not activate, separated easily from tritium, vacuum compatible, and undergoes no phase transformations. Recently, the thermal performance of a bare-copper, dual-channel, helium-cooled, porous metal divertor mock-up, designed and fabricated by Thermacore Inc., was evaluated on Sandia's 30 kW Electron Beam Test System equipped with a closed helium flow loop. The module uses short circumferential flow paths to minimize pressure drops and pumping requirements while achieving optimal thermal performance by providing a very large effective surface area. The module was tested under both uniform and non-uniform heat loads to assess the effects of mass flow instabilities. It survived a maximum absorbed heat flux of 29.5 MW/m(2) on a 2-cm(2) area. Results on the power sharing between the two channels is presented and compared with that of a previous design. These experimental results coupled with appropriate modeling provide insight on flow instabilities in multi-channel, helium-cooled heat exchangers. (C) 2000 Published by Elsevier Science B.V. C1 Sandia Natl Labs, Fus Technol Dept, Albuquerque, NM 87185 USA. Thermacore Inc, Lancaster, PA 17601 USA. RP Youchison, DL (reprint author), Sandia Natl Labs, Fus Technol Dept, POB 5860,MS-1129, Albuquerque, NM 87185 USA. EM dlyouch@sandia.gov OI Youchison, Dennis/0000-0002-7366-1710 NR 8 TC 8 Z9 8 U1 0 U2 2 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 NOV PY 2000 VL 49-50 BP 407 EP 415 DI 10.1016/S0920-3796(00)00243-X PG 9 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GW UT WOS:000165996300059 ER PT J AU Gohar, Y Majumdar, S Smith, D AF Gohar, Y Majumdar, S Smith, D TI High power density self-cooled lithium-vanadium blanket SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE first wall; blanket; lithium; vanadium; neutronics; spectral shifter; liquid metal blanket design AB A self-cooled lithium-vanadium blanket concept capable of operating with 2 MW/m(2) surface heat flux and 10 MW/m(2) neutron wall loading has been developed. The blanket has liquid lithium as the tritium breeder and the coolant to alleviate issues of coolant breeder compatibility and reactivity. Vanadium alloy (V-4Cr-4Ti) is used as the structural material because it can accommodate high heat loads. Also, it has good mechanical properties at high temperatures, high neutron fluence capability, low degradation under neutron irradiation, good compatibility with the blanket materials, low decay heat, low waste disposal rating, and adequate strength to accommodate the electromagnetic loads during plasma disruption events. Self-healing electrical insulator (CaO) is utilized to reduce the MHD pressure drop. A poloidal coolant flow with high velocity at the first wall is used to reduce the peak temperature of the vanadium structure and to accommodate high surface heat flux. The blanket has a simple geometrical configuration and low coolant pressure to reduce the fabrication cost, to improve the blanket reliability, and to increase confidence in its performance. Spectral shifter and reflector are utilized to improve the blanket shielding capability and energy multiplication, and to reduce the radial blanket thickness. Natural lithium is used to avoid extra cost related to the lithium enrichment process. (C) 2000 Published by Elsevier Science B.V. C1 Argonne Natl Lab, Fus Power Program, Argonne, IL 60439 USA. RP Gohar, Y (reprint author), Argonne Natl Lab, Fus Power Program, 9700 S Cass Ave, Argonne, IL 60439 USA. EM gohar@anl.gov NR 12 TC 17 Z9 17 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 NOV PY 2000 VL 49-50 BP 551 EP 558 DI 10.1016/S0920-3796(00)00279-9 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GW UT WOS:000165996300076 ER PT J AU Gulec, K Abdou, MA Moir, RW Morley, NB Ying, A AF Gulec, K Abdou, MA Moir, RW Morley, NB Ying, A TI Novel liquid blanket configurations and their hydrodynamic analyses for innovative confinement concepts SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE azimuthal; APEX; heavy-ion diffusion ID FLOW AB Hydrodynamics analyses as a part of the APEX (advanced power extraction) study demonstrates the potential application of applying swirling thick liquid walls to innovative confinement concepts such as field reversed configuration (FRC), spherical torus (ST) and heavy-ion fusion (HIF). This paper addresses the design and the hydrodynamic aspects of fusion relevant swirling flow including 3-D velocity distribution, variations of the flow height in axial and azimuthal directions and hydrodynamic flow stability. Numerical hydrodynamic analyses using a 3-D code with Flibe as the working fluid, shows that a thick liquid first-wall/blanket (> 0.6 m) can be maintained in a circular vacuum chamber of 2 m radius by injecting the liquid layer from one side through a swirl flow generating inlet with axial (7 m/s) and azimuthal (10 m/s) velocity components. Parametric computational study indicated that the liquid layer thickness in axial and azimuthal directions is strongly dependent on the inlet axial, azimuthal velocity values and gravitational acceleration. It also shows that a uniform liquid layer thickness can be maintained for axial and azimuthal inlet velocities of 11 and 13 m/s in a cylindrical chamber with a 2 m radius and 12 m length. The swirling liquid wall idea is applied successfully to ST and HIF configurations. A 2D linear stability analysis using potential flow theory (Reynolds number is similar to 10(6) for liquid wall thickness of similar to 0.5 m) of the swirling flow in the azimuthal flow direction suggested that mean flow is stable when the surface tension, gravitational acceleration, and the centrifugal force effects are considered. (C) 2000 Published by Elsevier Science B.V. C1 Univ Calif Los Angeles, Dept Mech & Aerosp Engn, Los Angeles, CA 90095 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. RP Gulec, K (reprint author), Univ Calif Los Angeles, Dept Mech & Aerosp Engn, Los Angeles, CA 90095 USA. EM kgulec@fusion.ucla.edu NR 17 TC 2 Z9 2 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 NOV PY 2000 VL 49-50 BP 567 EP 576 DI 10.1016/S0920-3796(00)00282-9 PG 10 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GW UT WOS:000165996300078 ER PT J AU Mattas, RF Malang, S Khater, H Majumdar, S Mogahed, E Nelson, B Sawan, M Sze, DK AF Mattas, RF Malang, S Khater, H Majumdar, S Mogahed, E Nelson, B Sawan, M Sze, DK TI EVOLVE - an advanced first wall/blanket system SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE lithium; alloys; tritium extraction AB A new concept for an advanced fusion first wall and blanket has been identified. The key feature of the concept is the use of the heat of vaporization of lithium (about 10 times higher than water) as the primary means for capturing and removing the fusion power. A reasonable range of boiling temperatures of this alkali metal is 1200-1400 degreesC, corresponding with a saturation pressure of 0.035-0.2 MPa. Calculations indicate that an evaporative system with Li at similar or equal to 1200 degreesC can remove a first wall surface heat flux of > 2 MW m(-2) with an accompanying neutron wall load of > 10 MW m(-2). Work to date shows that the system provides adequate tritium breeding and shielding, very high thermal conversion efficiency, and low system pressure. Tungsten is used as the structural material, and it is expected to operate at a surface wall load of 2 MW m(-2) at temperatures above 1200 degreesC. (C) 2000 Published by Elsevier Science B.V. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Forschungszentrum Karlsruhe, D-76021 Karlsruhe, Germany. Univ Wisconsin, Madison, WI USA. Oak Ridge Natl Lab, Oak Ridge, TN USA. RP Mattas, RF (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 4 TC 11 Z9 11 U1 2 U2 2 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 NOV PY 2000 VL 49-50 BP 613 EP 620 DI 10.1016/S0920-3796(00)00350-1 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GW UT WOS:000165996300084 ER PT J AU Sagara, A Yamanishi, H Imagawa, S Muroga, T Uda, T Noda, T Takahashi, S Fukumoto, K Yamamoto, T Matsui, H Kohyama, A Hasizume, H Toda, S Shimizu, A Suzuki, A Hosoya, Y Tanaka, S Terai, T Sze, DK Motojima, O AF Sagara, A Yamanishi, H Imagawa, S Muroga, T Uda, T Noda, T Takahashi, S Fukumoto, K Yamamoto, T Matsui, H Kohyama, A Hasizume, H Toda, S Shimizu, A Suzuki, A Hosoya, Y Tanaka, S Terai, T Sze, DK Motojima, O TI Design and development of the Flibe blanket for helical-type fusion reactor FFHR SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE blanket design; Flibe blanket; helical-type fusion reactor FFHR AB Blanket design is in progress in helical-type compact reactor FFHR-2. A localized blanket concept is proposed by selecting molten-salt Flibe as a self-cooling tritium breeder from the main reason of safety: low tritium solubility, low reactivity with air and water, low pressure operation, and low MHD resistance which is compatible with the high magnetic field design in force-free helical reactor (FFHR). Numerical results are presented on nuclear analyses using the MCNP-4B code, on thermal and stress analyses using the ABAQUS code, and heat exchange efficiency from Flibe to He. R&D programs on Flibe engineering are also in progress in material dipping-tests and in construction of molten salt loop. Preliminary results in these experiments are also presented. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Inst Fus Sci, LHD Project, Res Operat Div, Toki 5095292, Japan. Natl Res Inst Met, Tsukuba, Ibaraki 305, Japan. Tohoku Univ, Inst Mat Res, Sendai, Miyagi 980, Japan. Kyoto Univ, Inst Adv Energy, Uji 611, Japan. Kyushu Univ, Kasuga, Fukuoka 816, Japan. Univ Tokyo, Tokyo 113, Japan. Argonne Natl Lab, Argonne, IL 60439 USA. RP Sagara, A (reprint author), Natl Inst Fus Sci, LHD Project, Res Operat Div, Toki 5095292, Japan. EM sagara@lhd.nifs.ac.jp NR 7 TC 44 Z9 44 U1 2 U2 10 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 NOV PY 2000 VL 49-50 BP 661 EP 666 DI 10.1016/S0920-3796(00)00360-4 PG 6 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GW UT WOS:000165996300091 ER PT J AU Sawan, ME Khater, HY Sze, DK AF Sawan, ME Khater, HY Sze, DK TI Nuclear analysis for a flowing Li2O particulate blanket without structural first wall SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE nuclear analysis; Li2O particulate blanket; structural first wall ID FUSION AB Neutronics and activation calculations have been performed for a Li2O particulate blanket concept without structural first wall. The concept has the potential for achieving tritium self-sufficiency with a lifetime structure and reweldable vacuum vessel. It has attractive safety features resulting from the significant reduction in radioactivity and decay heat generation in the structural material. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Wisconsin, Fus Technol Inst, Madison, WI 53706 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP Sawan, ME (reprint author), Univ Wisconsin, Fus Technol Inst, 1500 Engn Dr, Madison, WI 53706 USA. EM sawan@engr.wisc.edu NR 9 TC 0 Z9 0 U1 1 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 NOV PY 2000 VL 49-50 BP 667 EP 673 DI 10.1016/S0920-3796(00)00361-6 PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GW UT WOS:000165996300092 ER PT J AU Tillack, MS Wang, X Pulsifer, J Malang, S Sze, DK AF Tillack, MS Wang, X Pulsifer, J Malang, S Sze, DK CA ARIES Team TI ARIES-ST breeding blanket design and analysis SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE breeding blanket; fusion; ARIES-ST AB ARIES-ST is a 1000 MW fusion power plant conceptual design based on a low aspect ratio 'spherical torus' (ST) plasma. The power core uses an advanced 'dual-cooled' breeding blanket with flowing PbLi breeder and He-cooled ferritic steel structures. The main features of the blanket design are summarized here together with analysis of the thermal hydraulic and thermomechanical performance. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif San Diego, La Jolla, CA 92093 USA. Forschungszentrum Karlsruhe, D-76021 Karlsruhe, Germany. Argonne Natl Lab, Argonne, IL 60439 USA. RP Tillack, MS (reprint author), Univ Calif San Diego, La Jolla, CA 92093 USA. EM tillack@fusion.ucsd.edu NR 12 TC 23 Z9 24 U1 6 U2 10 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 NOV PY 2000 VL 49-50 BP 689 EP 695 DI 10.1016/S0920-3796(00)00366-5 PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GW UT WOS:000165996300095 ER PT J AU Wong, CPC Nygren, RE Baxi, CB Fogarty, P Ghoniem, N Khater, H McCarthy, K Merrill, B Nelson, B Reis, EE Sharafat, S Schleicher, R Sze, DK Ulrickson, M Willms, S Youssef, M Zinkle, S AF Wong, CPC Nygren, RE Baxi, CB Fogarty, P Ghoniem, N Khater, H McCarthy, K Merrill, B Nelson, B Reis, EE Sharafat, S Schleicher, R Sze, DK Ulrickson, M Willms, S Youssef, M Zinkle, S CA APEX Team TI Helium-cooled refractory alloys first wall and blanket evaluation SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE He-cooled system; refractory alloys; first wall and blanket designs ID FUSION AB Under the APEX program the He-cooled system design task is to evaluate and recommend high power density refractory alloy first wall and blanket designs and to recommend and initiate tests to address critical issues. We completed the preliminary design of a helium-cooled, W-5Re alloy, lithium breeder design and the results are reported in this paper. Many areas of the design were assessed, including material selection, helium impurity control, and mechanical, nuclear and thermal hydraulics design, and waste disposal, tritium and safety design. Systems study results show that at a closed cycle gas turbine (CCGT) gross thermal efficiency of 57.5%, a superconducting coil tokamak reactor, with an aspect ratio of 4, and an output power of 2 GWe, can be projected to have a cost of electricity at 54.6 mill/kW h. Critical issues were identified and we plan to continue the design on some of the critical issues during the next phase of the APEX design study. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Gen Atom Co, San Diego, CA 92186 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Oak Ridge Natl Lab, Oak Ridge, TN USA. Univ Wisconsin, Madison, WI USA. Univ Calif Los Angeles, Los Angeles, CA USA. Lockheed Martin Idaho Technol Co, Idaho Falls, ID USA. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Wong, CPC (reprint author), Gen Atom Co, POB 85608, San Diego, CA 92186 USA. EM clement.wong@gat.com RI Ghoniem, Nasr/A-9799-2008 NR 17 TC 14 Z9 14 U1 1 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 NOV PY 2000 VL 49-50 BP 709 EP 717 DI 10.1016/S0920-3796(00)00176-9 PG 9 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GW UT WOS:000165996300098 ER PT J AU Futterer, MA Albrecht, H Giroux, P Glugla, M Kawamura, H Kveton, OK Murdoch, DK Sze, DK AF Futterer, MA Albrecht, H Giroux, P Glugla, M Kawamura, H Kveton, OK Murdoch, DK Sze, DK TI Tritium technology for blankets of fusion power plants SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE tritium; technology; fusion power plant; breeder blanket ID RECOVERY AB Thermonuclear fusion power stations based on the deuterium-tritium reaction require breeding blankets to produce the tritium (T) fuel consumed in the plasma. This paper resumes the state-of-the-art of the T related technology from the initial T production in the lithium-bearing breeder material to a T stream which is ready for re-injection into the plasma. The remaining development issues are outlined and conventional techniques are confronted with advanced methods requiring more R&D effort but promising certain advantages in return. (C) 2000 Published by Elsevier Science B.V. C1 CEA Saclay, DRN, DMT, SERMA, F-91191 Gif Sur Yvette, France. Forschungszentrum Karlsruhe, Tritiumlab, D-76021 Karlsruhe, Germany. CEA Valduc, Serv Tritium, F-21120 Is Sur Tille, France. Japan Atom Energy Res Inst, Naka, Ibaraki 31101, Japan. IPP, NET Team, D-85748 Garching, Germany. Argonne Natl Lab, Argonne, IL 60439 USA. RP Futterer, MA (reprint author), CEA Saclay, DRN, DMT, SERMA, F-91191 Gif Sur Yvette, France. EM michael.futterer@cea.fr NR 26 TC 8 Z9 8 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 NOV PY 2000 VL 49-50 BP 735 EP 743 DI 10.1016/S0920-3796(00)00204-0 PG 9 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GW UT WOS:000165996300101 ER PT J AU Yamada, H Sakamoto, R Oda, Y Hiramatsu, T Kinoshita, M Ogino, M Matsuda, R Sudo, S Kato, S Fisher, PW Baylor, LR Gouge, M AF Yamada, H Sakamoto, R Oda, Y Hiramatsu, T Kinoshita, M Ogino, M Matsuda, R Sudo, S Kato, S Fisher, PW Baylor, LR Gouge, M TI Development of pellet injector system for large helical device SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE pellet injector; GM cycle; LHD ID HYDROGEN PELLET AB A multi-pellet injector system has been developed as a fundamental fueling tool for the Large Helical Device (LHD). Since a primary goal of the LHD project is demonstration of steady-state high-temperature plasmas, highly reliable and reproducible performance is prerequisite for the LHD pellet injector. The helium Gifford-McMahon (GM) cycle cryogenic refrigerator and conventional pipe-gun mechanism have been employed along with these requirements. Since the triple point temperature of hydrogen is lower than those of isotopes; deuterium and tritium, a careful and steady temperature control is necessary in pellet formation. The amount of propellant gas has been minimized by small reservoir to reduce heat load and inflow into the plasma vacuum chamber. Both robustness and flexibility have been realized by using the programmable logic controller combined with GUI on WindowsNT. The pellet injector has demonstrated continuous hundreds of injection without any fail and has been applied for the LHD experiment successfully. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Inst Fus Sci, Gifu 5095292, Japan. Mitsubishi Heavy Ind Ltd, Adv Nucl Plant & Fuel Cycle Eng, Hyogo Ku, Kobe, Hyogo 6528585, Japan. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Yamada, H (reprint author), Natl Inst Fus Sci, 322-6 Oroshi Cho, Gifu 5095292, Japan. EM hyamada@lhd.nifs.ac.jp RI Sakamoto, Ryuichi/E-7557-2013 OI Sakamoto, Ryuichi/0000-0002-4453-953X NR 9 TC 25 Z9 27 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 NOV PY 2000 VL 49-50 BP 915 EP 920 DI 10.1016/S0920-3796(00)00342-2 PG 6 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GW UT WOS:000165996300124 ER PT J AU Willms, RS Arzu, PR Honnell, KG Birdsell, SA AF Willms, RS Arzu, PR Honnell, KG Birdsell, SA TI Initial testing of a low pressure permeator for tritium processing SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 5th International Symposium on Fusion Nuclear Technology CY SEP 19-24, 1999 CL ROME, ITALY DE permeator; tritium; oxidation/adsorption C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Willms, RS (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. EM willms@lanl.gov NR 1 TC 9 Z9 9 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0920-3796 J9 FUSION ENG DES JI Fusion Eng. Des. PD NOV PY 2000 VL 49-50 BP 963 EP 970 DI 10.1016/S0920-3796(00)00462-2 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 385GW UT WOS:000165996300131 ER PT J AU Anderl, RA Pawelko, RJ Smolik, GR Scaffidi-Argentina, F Davydov, D AF Anderl, RA Pawelko, RJ Smolik, GR Scaffidi-Argentina, F Davydov, D TI Steam chemical reactivity of Be pebbles and Be powder SO FUSION TECHNOLOGY LA English DT Article; Proceedings Paper CT 4th International Workshop on Beryllium Technology for Fusion CY SEP 15-17, 1999 CL KARLSRUHE, GERMANY SP Int Energy Agcy, Fus Mat DE beryllium pebbles; beryllium powder; specific surface areas; steam chemical reactivity ID BERYLLIUM AB This paper reports the results of chemical reactivity experiments for Be pebbles (2-mm and 0.2-mm diameter) and Be powder (14-31 mum diameter) exposed to steam at elevated temperatures, 350 to 900 degreesC for pebbles and 400 to 500 degreesC for powders. We measured BET specific surface areas of 0.12 m(2)/g for 2-mm pebbles, 0.24 m(2)/g for 0.2mm pebbles and 0.66 to 1.21 m(2)/g for Be powder samples. These experiments showed a complex reactivity behavior for the material, dependent primarily on the test temperature. Average H-2 generation rates for powder samples, based on measured BET surface areas, were in good agreement with previous measurements for fully-dense CPM-Be. Rates for the Be pebbles, based on measured BET surface areas, were systematically lower than the CPM-Be rates, possibly because of different surface and bulk features for the pebbles, especially surface-layer impurities, that contribute to the measured BET surface area and influence the oxidation process at the material surface. C1 Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. Forschungszentrum Karlsruhe, Inst Kern & Energietech, D-76021 Karlsruhe, Germany. VNIINM, Bochvar All Russian Res Inst Inorgan Mat, Moscow, Russia. RP Anderl, RA (reprint author), Idaho Natl Engn & Environm Lab, POB 1625, Idaho Falls, ID 83415 USA. NR 14 TC 3 Z9 4 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0748-1896 J9 FUSION TECHNOL JI Fusion Technol. PD NOV PY 2000 VL 38 IS 3 BP 283 EP 289 PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 367FK UT WOS:000090050900005 ER PT J AU Lodato, A Rodig, M Duwe, R Derz, H Linke, J Castro, R Gervash, A AF Lodato, A Rodig, M Duwe, R Derz, H Linke, J Castro, R Gervash, A TI Heat shock tests on beryllium samples before and after neutron irradiation SO FUSION TECHNOLOGY LA English DT Article; Proceedings Paper CT 4th IEA International Workshop on Beryllium Technology for Fusion CY SEP 15-17, 1999 CL KARLSRUHE, GERMANY SP Int Energy Agcy, Implementing Agreement Program Res & Dev Fus Mat DE beryllium; neutron irradiation; thermal shock; high heat flux testing AB Beside carbon materials and tungsten, beryllium will play an important role as plasma facing material (PFM) in the International Thermonuclear Experimental Reactor (ITER). It will mainly be used for the primary wall, the limiter and the upper baffle. During off normal operation the surface of Be may be loaded by severe thermal shocks, caused by plasma disruptions with energies of several ten MJ/m(2) within tens of milliseconds. The influence of high heat fluxes on several un-irradiated Be grade have been investigated before. During the operation of ITER the material will suffer irradiation with 14 MeV neutrons generated in the fusion process. In order to study the material degradation caused by fast neutrons, different samples have been neutron irradiated in the High Flux Reactor (HFR) at Petten. The thermal shock behaviour of the different beryllium grade before and after neutron irradiation is now compared. C1 Forschungszentrum Julich, EURATOM Assoc, D-52425 Julich, Germany. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. DV Efremov Sci Res Inst Electrophys Apparatus, St Petersburg 189631, Russia. RP Forschungszentrum Julich, EURATOM Assoc, Postfach 1913, D-52425 Julich, Germany. NR 5 TC 0 Z9 0 U1 0 U2 0 PU AMER NUCLEAR SOC PI LA GRANGE PK PA 555 N KENSINGTON AVE, LA GRANGE PK, IL 60526 USA SN 0748-1896 J9 FUSION TECHNOL JI Fusion Technol. PD NOV PY 2000 VL 38 IS 3 BP 334 EP 337 PG 4 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 367FK UT WOS:000090050900011 ER PT J AU Castro, RG Hollis, KJ Maggiore, CJ Ayala, A Bartram, BD Doerner, RP AF Castro, RG Hollis, KJ Maggiore, CJ Ayala, A Bartram, BD Doerner, RP TI Negative transferred arc cleaning: A method for roughening and removing surface contamination from beryllium and other metallic surfaces SO FUSION TECHNOLOGY LA English DT Article; Proceedings Paper CT 4th International Workshop on Beryllium Technology for Fusion CY SEP 15-17, 1999 CL KARLSRUHE, GERMANY SP Int Energy Agcy, Fus Mat DE beryllium plasma spray; negative transferred-arc cleaning; tritium removal ID GRAPHITE; HYDROGEN; TRITIUM; EROSION AB TA cleaning has been investigated for preparing the surface of beryllium plasma facing components (PFC's) inside of the International Thermonuclear Experimental Reactor (ITER) prior to depositing beryllium by plasma spraying. Plasma spraying of beryllium was evaluated during the ITER Engineering Design Activity (EDA) for in-situ repair and initial fabrication of the beryllium first wall armor. Results have shown that surface roughening of beryllium, during the TA cleaning process, can result in bond strengths greater than 100 MPa between beryllium surfaces and plasma sprayed beryllium. In addition, the TA cleaning process was shown to be an effective method for removing contaminate layers of carbon and tungsten from the surface of beryllium. Investigations have been performed to characterize the different are-types that occur during the TA cleaning process (Type I, II and III arcs) and the effectiveness of the TA cleaning process for potentially removing co-deposited layers of carbon and deuterium from the surface of beryllium, stainless steel and tungsten. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. RP Castro, RG (reprint author), Univ Calif Los Alamos Natl Lab, POB 1163, Los Alamos, NM 87545 USA. NR 9 TC 2 Z9 2 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0748-1896 J9 FUSION TECHNOL JI Fusion Technol. PD NOV PY 2000 VL 38 IS 3 BP 369 EP 375 PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 367FK UT WOS:000090050900016 ER PT J AU Longhurst, GR Anderl, RA Willms, RS AF Longhurst, GR Anderl, RA Willms, RS TI Tritium loss in molten Flibe systems SO FUSION TECHNOLOGY LA English DT Article; Proceedings Paper CT 4th International Workshop on Beryllium Technology for Fusion CY SEP 15-17, 1999 CL KARLSRUHE, GERMANY SP Int Energy Agcy, Fus Mat ID SALT AB An emerging issue relative to beryllium technology in fusion involves tritium interactions with molten beryllium-bearing salts. Innovative designs for fusion reactors, both magnetic and inertially confined, feature the molten salt mixture 2LiF . BeF2, commonly called Flibe, as a tritium breeder and coolant. Tritium is bred in the Flibe as neutrons from the plasma are absorbed by Li atoms, which then transmute to tritium and helium. Transmutation of tritium from Be also occurs. Among the issues to be resolved for such coolant systems is the potential loss of tritium from the Flibe coolant to the walls of the system, particularly through heat exchanger tubes, and from there into secondary coolants or working fluids and the environment. Effectively removing tritium from Flibe in clean-up units is also important. In quiescent or low Reynolds number flow, tritium movement through Flibe is governed by diffusion. For Flibe in turbulent flow, as in heat exchanger tubes, transport is by turbulent mixing, and the same flow conditions and structural design features that maximize heat transfer to the heat exchanger walls will enhance the transport of tritium to those same surfaces. Analyses have been performed to estimate the fractional loss of tritium through heat exchanger tubes and release rates from Flibe droplets in vacuum disengagers in molten Flibe systems. The calculations suggest unacceptably large losses of tritium through heat exchanger tubes. The gravity of the implications of these estimates calls for experimental verification to determine if tritium losses through molten Flibe heat exchangers or other Flibe systems can really be so high and whether vacuum disengagers will really work. There is also a need for better information on evolution of tritium from Flibe droplets in a vacuum. Several experiments are presently being planned to address these issues and are discussed. These include experiments to induce tritium in Flibe using spontaneous fission neutrons, experiments in flowing loops to evaluated tritium losses through heat exchanger walls, and exploration of schemes for tritium extraction from molten Flibe. C1 Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Longhurst, GR (reprint author), Idaho Natl Engn & Environm Lab, POB 1625, Idaho Falls, ID 83415 USA. NR 20 TC 1 Z9 1 U1 0 U2 1 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0748-1896 J9 FUSION TECHNOL JI Fusion Technol. PD NOV PY 2000 VL 38 IS 3 BP 376 EP 383 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 367FK UT WOS:000090050900017 ER PT J AU Cai, H White, PS Torney, D Deshpande, A Wang, ZL Keller, RA Marrone, B Nolan, JP AF Cai, H White, PS Torney, D Deshpande, A Wang, ZL Keller, RA Marrone, B Nolan, JP TI Flow cytometry-based minisequencing: A new platform for high-throughput single-nucleotide polymorphism scoring (vol 66, pg 135, 2000) SO GENOMICS LA English DT Correction C1 Univ Calif Los Alamos Natl Lab, Biosci Div, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Cai, H (reprint author), Univ Calif Los Alamos Natl Lab, Biosci Div, POB 1663, Los Alamos, NM 87545 USA. NR 1 TC 2 Z9 2 U1 1 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 NOV 1 PY 2000 VL 69 IS 3 BP 395 EP 395 DI 10.1006/geno.2000.6335 PG 1 WC Biotechnology & Applied Microbiology; Genetics & Heredity SC Biotechnology & Applied Microbiology; Genetics & Heredity GA 371GB UT WOS:000165169500014 ER PT J AU Felmy, AR Onishi, LM Foster, NS Rustad, JR Rai, D Mason, MJ AF Felmy, AR Onishi, LM Foster, NS Rustad, JR Rai, D Mason, MJ TI An aqueous thermodynamic model for the Pb2+-Na+-K+-Ca2+-Mg2+-H+-Cl--SO42--H2O system to high concentration: Application to WIPP brines SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID NATURAL-WATERS; LEAD CHLORIDE; SOLUBILITY; COEFFICIENTS; 25-DEGREES-C; PREDICTION; EQUILIBRIA; CARBONATE; EQUATIONS; COMPLEXES AB The development of an aqueous thermodynamic model for the Pb2+-Na+-K+-Ca2+-Mg2+-Cl--SO42--H2O system is presented, which is valid to high ionic strengths at 25 degreesC. The model is based on the equations of Pitzer and has been parameterized from existing solubility, osmotic, electromotive force (emf), and spectroscopic data. To accurately represent the aqueous thermodynamics of Pb2+ in concentrated chloride containing solutions required the inclusion of four Pb chloride species (i.e., PbCl+, PbCl2(aq), PbCl3-, and PbCl42-) along with the necessary Pitzer ion interaction parameters for these species with the major electrolyte ions. The reliability of the final equilibrium model is tested against experimental solubility data on PbCl2(c) and PbSO4(c) in high ionic strength Waste Isolation Pilot Plant (WIPP) brines obtained as part of this study. On an overall basis the model accurately predicted the aqueous speciation, based on comparisons with our UV-Vis spectroscopy measurements, as well as the observed solubility. The model also proved satisfactory in predicting the observed solid phase assemblages, with the possible exception of those found in solutions high in KCl. Copyright (C) 2000 Elsevier Science Ltd. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Pacific NW Natl Lab, Richland, WA 99352 USA. EM ar.felmy@pnl.gov NR 28 TC 6 Z9 7 U1 0 U2 5 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 NOV PY 2000 VL 64 IS 21 BP 3615 EP 3628 DI 10.1016/S0016-7037(00)00454-3 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 371FZ UT WOS:000165169300001 ER PT J AU Fenter, P Teng, H Geissbuhler, P Hanchar, JM Nagy, KL Sturchio, NC AF Fenter, P Teng, H Geissbuhler, P Hanchar, JM Nagy, KL Sturchio, NC TI Atomic-scale structure of the orthoclase (001)-water interface measured with high-resolution X-ray reflectivity SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID CALCITE-WATER INTERFACE; DISSOLUTION KINETICS; SURFACE; ALBITE; ADSORPTION; TEMPERATURE; PRESSURE AB In situ X-ray specular reflectivity and atomic force microscopy were used to determine the structure of the orthoclase (001) cleavage surface in contact with deionized water at 25 degreesC. These are the first in situ measurements of the orthoclase-water interface structure performed to Angstrom-scale resolution. The orthoclase (001) cleavage surface has minimal roughness, and only one of two possible surface terminations is exposed. The X-ray data show that (1) the silica network at the orthoclase surface is terminated by an oxygen-containing species (e.g., O or OH) having a coverage of 1.9 +/- 0.25 ML (the expected coverage is 2.0 ML, where 1 ML = 1 atom/55.76 Angstrom (2)), (2) the outermost layer of K+ ions have been removed with a derived coverage of 0.0 +/- 0.08 ML (the bulk truncated K+ coverage is 1.0 ML), and (3) a complex relaxation profile affecting the near-surface structure propagates similar to 26 Angstrom into the orthoclase with a maximum relaxation of similar to0.15 Angstrom near the surface. These data are inconsistent with K+ ion depletion below the topmost K+ layer. These results provide a new baseline for understanding the initial steps of the feldspar dissolution process, demonstrate the power of combining X-ray scattering techniques with scanning probe microscopies for understanding the intrinsic characteristics of complex mineral-water interface systems, and suggest a new approach for understanding feldspar dissolution mechanisms. Copyright (C) 2000 Elsevier Science Ltd. C1 Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. Univ Washington, Dept Phys, Seattle, WA 98195 USA. George Washington Univ, Dept Earth & Environm Sci, Washington, DC 20006 USA. Univ Colorado, Dept Geol Sci, Boulder, CO 80309 USA. RP Fenter, P (reprint author), Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. EM fenter@anl.gov NR 26 TC 69 Z9 69 U1 0 U2 24 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 NOV PY 2000 VL 64 IS 21 BP 3663 EP 3673 DI 10.1016/S0016-7037(00)00455-5 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 371FZ UT WOS:000165169300004 ER PT J AU Clapp, EM Bierman, PR Schick, AP Lekach, J Enzel, Y Caffee, M AF Clapp, EM Bierman, PR Schick, AP Lekach, J Enzel, Y Caffee, M TI Sediment yield exceeds sediment production in arid region drainage basins SO GEOLOGY LA English DT Article DE Be-10; Al-26; Nahal Yael; cosmogenic; erosion rates; sediment generation rates ID ALLUVIAL SEDIMENT; RATES; DENUDATION; EROSION; BE-10 AB We use Be-10 and Al-26 to determine long-term sediment generation rates, identify significant sediment sources, and test for landscape steady state in Nahal Yael, an extensively studied, hyperarid drainage basin in southern Israel. Comparing a 33 yr sediment budget with 33 paired Be-10 and Al-26 analyses indicates that short-term sediment yield (113-138 t.km(-2).yr(-1)) exceeds long-term sediment production (74 +/- 16t.km(-2).yr(-1)) by 53%-86%. The difference suggests that the basin is not in steady state, but is currently evacuating sediment accumulated during periods of more rapid sediment generation and lower sediment yield. Nuclide data indicate that (1) sediment leaving the basin is derived primarily from hillslope colluvium, (2) bedrock weathers more rapidly beneath a cover of colluvium than when exposed, and (3) long-term erosion rates of granite, schist, and amphibolite are similar. C1 Univ Vermont, Sch Nat Resources, Burlington, VT 05401 USA. Univ Vermont, Dept Geol, Burlington, VT 05401 USA. Hebrew Univ Jerusalem, Dept Geog, Jerusalem, Israel. Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94551 USA. RP Clapp, EM (reprint author), Sevee & Maher Engineers Inc, 4 Blanchard Rd,Box 85A, Cumberland Ctr, ME 04021 USA. RI Caffee, Marc/K-7025-2015 OI Caffee, Marc/0000-0002-6846-8967 NR 23 TC 81 Z9 83 U1 2 U2 10 PU GEOLOGICAL SOC AMERICA, INC PI BOULDER PA PO BOX 9140, BOULDER, CO 80301-9140 USA SN 0091-7613 J9 GEOLOGY JI Geology PD NOV PY 2000 VL 28 IS 11 BP 995 EP 998 DI 10.1130/0091-7613(2000)28<995:SYESPI>2.0.CO;2 PG 4 WC Geology SC Geology GA 373FP UT WOS:000165277900009 ER PT J AU Olsson, WA Holcomb, DJ AF Olsson, WA Holcomb, DJ TI Compaction localization in porous rock SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID COMPRESSION; DEFORMATION; BANDS AB Experimental work on shear localization in porous sandstone led to the observation of nonuniform compaction. By analogy with shear localization, the process is referred to as compaction localization. To gain insight into the process of compaction localization, acoustic emission locations were used to define and track the thicknesses of localized zones of compaction during axisymmetric compression experiments. Zones of acoustic emission, demarcating the boundaries between the uncompacted and compacted regions, developed and moved parallel to the sample axis at velocities an order of magnitude higher than the imposed specimen shortening rate. Thus tabular zones of compaction were found to grow (thicken) in the direction of maximum compressive stress. These structures may form due to tectonic stresses or as a result of local stresses induced during production of fluids from wells, resulting in barriers to fluid (oil, gas, water) movement in sandstone reservoirs. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Olsson, WA (reprint author), Sandia Natl Labs, POB 5800,MS 0751, Albuquerque, NM 87185 USA. NR 16 TC 77 Z9 87 U1 2 U2 4 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 NOV 1 PY 2000 VL 27 IS 21 BP 3537 EP 3540 DI 10.1029/2000GL011723 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 369JW UT WOS:000165063000027 ER PT J AU Kaplan, DI Kutnyakov, IV Gamerdinger, AP Serne, RJ Parker, KE AF Kaplan, DI Kutnyakov, IV Gamerdinger, AP Serne, RJ Parker, KE TI Gravel-corrected Kd values SO GROUND WATER LA English DT Article AB Standard measurements of solute sorption to sediments are typically made on the <2 mm sediment fraction. This fraction is used by researchers to standardize the method and to ease experimental protocol so that large labware is not required to accommodate the gravel fraction (>2 mm particles). Since sorption is a phenomenon directly related to surface area, sorption measurements based on the <2 mm fraction would be expected to overestimate actual whole-sediment values for sediments containing gravel. This inaccuracy is a problem for ground water contaminant transport modelers who use laboratory-derived sorption values, typically expressed as a distribution coefficients (Kd), to calculate the retardation factor (Rf), a parameter that accounts for solute-sediment chemical interactions. The objectives of this laboratory study were to quantify the effect of gravel on strontium Kd and Rf values and to develop an empirical method to calculate gravel-corrected Kd values for the study site (Hanford Site in Richland, Washington). Three gravel corrections, Kd(gc) values, were evaluated: a correction based on the assumption that the gravel simply diluted the Kd(< 2mm) and had no sorption capacity (Kd(gc),(g=0)), a correction based on the assumption that the Kd of the intact sediment (Kd(tot)) was a composite of the Kd(< 2mm) and the Kd(> 2mm) (Kd(gc,g=x)), and a correction based on surface area (Kd(gc,surf)). On average, Kd(< 2mm) tended to overestimate Kd(tot) by 28% to 47%; Kd(gc,g=x) overestimated Kd(tot) by only 3% to 5%; and Kd(gc,g=0) and Kd(gc,surf) underestimated Kd(tot) by 10% to 39%. Kd(gc,g=x) provided the best estimate of actual values (Kd(tot)); however, Kd(gc,g=0) was appreciably easier to acquire. Although other contaminants will likely have different gravel-correction values, these results have important implications regarding the traditional approach to modeling contaminant transport which uses Kd(< 2mm) values. Such calculations may overestimate the tendency of gravel-containing sediments to retard contaminant migration. C1 Westinghouse Savannah River Co, Savannah River Technol Ctr, Aiken, SC 29808 USA. Pacific NW Natl Lab, Richland, WA 99352 USA. Washington State Univ, Dept Chem, Richland, WA 99352 USA. RP Kaplan, DI (reprint author), Westinghouse Savannah River Co, Savannah River Technol Ctr, Aiken, SC 29808 USA. NR 14 TC 7 Z9 7 U1 1 U2 1 PU GROUND WATER PUBLISHING CO PI WESTERVILLE PA 601 DEMPSEY RD, WESTERVILLE, OH 43081 USA SN 0017-467X J9 GROUND WATER JI Ground Water PD NOV-DEC PY 2000 VL 38 IS 6 BP 851 EP 857 DI 10.1111/j.1745-6584.2000.tb00683.x PG 7 WC Geosciences, Multidisciplinary; Water Resources SC Geology; Water Resources GA 371GA UT WOS:000165169400014 ER PT J AU Davis, SN Fabryka-Martin, J Wolfsberg, L Moysey, S Shaver, R Alexander, EC Krothe, N AF Davis, SN Fabryka-Martin, J Wolfsberg, L Moysey, S Shaver, R Alexander, EC Krothe, N TI Chlorine-36 in ground water containing low chloride concentrations SO GROUND WATER LA English DT Article ID AQUIFER; RATIOS; CL-36 AB Analyses of ground water from wells and springs in the United States indicate a broad regional trend in preanthropogenic ((CI)-C-36/total CI) x 10(15) ratios in potable water. Coastal areas influenced by marine chloride have ratios less than 100. These ratios increase inland and reach a maximum of about 1400 in the central and northern Rocky Mountains. However, the magnitude of these regional variations is greatly exceeded at a local level if water samples are considered regardless of age or origin. Most local departures from regional trends can be attributed to mixing of ground water recharge with either (CI)-C-36 from nuclear fusion tests to produce higher ratios or mixing with sources of old chloride such as from evaporite minerals to produce lower ratios. A useful interpretation of (CI)-C-36 data is difficult unless the origin of the chloride is understood. The interpretation is an unusually difficult problem for water having low chloride concentrations. The assumption that low concentrations originate primarily from wet and dry atmospheric deposition can be questioned even for some dilute waters with less than 2.0 mg/L chloride. Chloride/bromide ratios in ground water can help decipher the origin of the chloride. The presence of nonatmospheric chloride can be identified in part by its association with chloride/bromide mass ratios greater than about 200 in coastal areas and 100 in inland areas. Accurate chloride and bromide analyses are recommended for virtually all studies of (CI)-C-36 in natural waters, and particularly those with low concentrations of chloride. C1 Univ Arizona, Dept Hydrol & Water Resources, Tucson, AZ 85721 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ British Columbia, Dept Earth & Ocean Sci, Vancouver, BC V6T 1Z4, Canada. N Dakota State Water Commiss, Water Appropriat Div, Bismarck, ND 58505 USA. Univ Minnesota, Dept Geol & Geophys, Minneapolis, MN 55455 USA. Indiana Univ, Dept Geol Sci, Bloomington, IN 47405 USA. RP Davis, SN (reprint author), Univ Arizona, Dept Hydrol & Water Resources, Tucson, AZ 85721 USA. RI Moysey, Stephen/H-4658-2012 NR 39 TC 9 Z9 9 U1 1 U2 3 PU GROUND WATER PUBLISHING CO PI WESTERVILLE PA 601 DEMPSEY RD, WESTERVILLE, OH 43081 USA SN 0017-467X J9 GROUND WATER JI Ground Water PD NOV-DEC PY 2000 VL 38 IS 6 BP 912 EP 921 DI 10.1111/j.1745-6584.2000.tb00691.x PG 10 WC Geosciences, Multidisciplinary; Water Resources SC Geology; Water Resources GA 371GA UT WOS:000165169400022 ER PT J AU Blakely, EA AF Blakely, EA TI Biological effects of cosmic radiation: Deterministic and stochastic SO HEALTH PHYSICS LA English DT Review DE National Council on Radiation Protection and; Measurements; exposure, occupational; radiation, cosmic; health effects ID ATOMIC-BOMB SURVIVORS; INDUCED GENOMIC INSTABILITY; HEAVY-PARTICLE IRRADIATION; SISTER-CHROMATID EXCHANGES; TOTAL-BODY IRRADIATION; DOUBLE-STRAND BREAKS; SHORT DNA FRAGMENTS; REVISED DOSES DS86; GROWTH-FACTOR-BETA; IONIZING-RADIATION AB Our basic understanding of the biological responses to cosmic radiations comes in large part from an international series of ground-based laboratory studies, where accelerators have provided the source of representative charged particle radiations. Most of the experimental studies have been performed using acute exposures to a single radiation type at relatively high doses and dose rates. However, most exposures in flight occur from low doses of mixed radiation fields at low-dose rates. This paper provides a brief overview of existing pertinent clinical and biological radiation data and the limitations associated with data available from specific components of the radiation fields in airflight and space travel. C1 Ernest Orlando Lawrence Berkeley Natl Lab, Berkeley, CA 94702 USA. EM eablakely@lbl.gov RI huang, hongqi/N-1473-2014 FU NEI NIH HHS [EY-10737] NR 113 TC 34 Z9 35 U1 2 U2 6 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 NOV PY 2000 VL 79 IS 5 BP 495 EP 506 DI 10.1097/00004032-200011000-00006 PG 12 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 364LD UT WOS:000089893100006 PM 11045523 ER PT J AU Goldhagen, P AF Goldhagen, P TI Overview of aircraft radiation exposure and recent ER-2 measurements SO HEALTH PHYSICS LA English DT Article DE National Council on Radiation Protection and; Measurements; exposure, occupational; radiation, cosmic; neutrons ID HIGH-ENERGY NEUTRONS; DOSE-EQUIVALENT; CONVERSION COEFFICIENTS; QUALITY FACTORS; COSMIC-RAYS; SPECTRA; ATMOSPHERE; ALTITUDES; FLUENCE; AMBIENT AB The intensity of the different particles making up atmospheric cosmic radiation, their energy distribution, and their potential biological effect on aircraft occupants vary with altitude, geomagnetic latitude, and time in the sun's magnetic activity cycle. Dose rates from cosmic radiation at commercial aviation altitudes are such that crews working on present-day jet aircraft are an occupationally exposed group with a relatively high average effective dose. Crews of future high speed commercial aircraft flying at higher altitudes would be even more exposed. Present calculations of such exposures are uncertain because knowledge of important components of the radiation field comes primarily from theoretical predictions. To help reduce these uncertainties for high-altitude flight, the National Aeronautics and Space Administration (NASA) and the Department of Energy (DOE) started the Atmospheric Ionizing Radiation (AIR) project. The measurement part of the AIR project is an international collaboration of 12 laboratories placing 14 instruments on multiple flights of a NASA ER-2 aircraft. This paper describes the basic features of cosmic radiation in the atmosphere as they relate to exposure of aircraft occupants and then describes the AIR ER-2 measurements and presents some preliminary results from a series of flights in June 1997. C1 US DOE, Environm Measurements Lab, New York, NY 10014 USA. EM goldhagn@eml.doe.gov RI huang, hongqi/N-1473-2014 NR 62 TC 53 Z9 55 U1 0 U2 4 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 NOV PY 2000 VL 79 IS 5 BP 526 EP 544 DI 10.1097/00004032-200011000-00009 PG 19 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 364LD UT WOS:000089893100009 PM 11045526 ER PT J AU Chee, PA Braby, LA Conroy, TJ AF Chee, PA Braby, LA Conroy, TJ TI Potential doses to passengers and crew of supersonic transports SO HEALTH PHYSICS LA English DT Article DE National Council on Radiation Protection and; Measurements; exposure, occupational; radiation, cosmic; exposure, population AB Data from a tissue equivalent proportional counter that was flown at altitudes ranging from 60,000 feet to 70,000 feet were used to estimate radiation quality factors at different latitudes. For high LET radiation, Q values of 11 to 14 were calculated for latitude 18 degrees north to 59 degrees north. Dose equivalent rates ranging from 5.2 mu Sv hr(-1) to 27 mu Sv hr(-1) were measured. These dose equivalent rates are about twice that computed using a computer code called CARI-4Q. The dose equivalent received during a flight from Los Angeles to Tokyo was computed using CARI-4Q and the result doubled, based on the TEPC to CARI-4Q ratio. Members of the general public, including frequent flyers, would not exceed dose limits recommended by the ICRP. Air crew would not exceed the limits for occupationally exposed persons. However, pregnant air crew, based on a 2 mSv limit to concepti, would exceed the limit after 150 hours flying time. C1 Boeing Co, Seattle, WA 98124 USA. Texas A&M Univ, College Stn, TX 77843 USA. Pacific NW Natl Lab, Richland, WA 99352 USA. EM alexander.chee@boeing.com NR 7 TC 9 Z9 9 U1 0 U2 1 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD NOV PY 2000 VL 79 IS 5 BP 547 EP 552 DI 10.1097/00004032-200011000-00011 PG 6 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 364LD UT WOS:000089893100011 PM 11045528 ER PT J AU Vickers, L Eifert, E AF Vickers, L Eifert, E TI The quality evaluation program for plutonium pits at the US DOE Pantex Plant SO HEALTH PHYSICS LA English DT Article DE operational topic; as low as reasonably achievable (ALARA) plutonium; exposure, occupational AB The United States Department of Energy Pantex Plant quality evaluation program for plutonium pits is an extensive program that includes I) weigh and leak check system; 2) radiography; and 3) dye penetrant testing. Successful completion of these diagnostics qualifies a pit to remain in the active status stockpile program. The use of lead aprons and a robot when handling the plutonium pits minimizes personnel exposures to ionizing radiation. All personnel exposures to ionizing radiation at Pantex Plant are As Low As Reasonably Achievable. C1 US DOE, Pantex Plant, Amarillo, TX 79120 USA. EM lvickers@pantex.com 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 NOV PY 2000 VL 79 IS 5 SU S BP S96 EP S100 DI 10.1097/00004032-200011001-00013 PG 5 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 364WN UT WOS:000089917200011 PM 11045519 ER PT J AU Sakhaee, M Zhu, SJ Gan, CY Zhu, LY Yan, LM Xu, RQ Jon, MG Jiang, Z Zhang, Z Hamilton, JH Ramayya, AV Babu, BRS Hwang, JK Ma, WC Komicki, J Cole, JD Aryaeinejad, R Drigert, MW Rasmussen, JO Stoyer, MA Chu, SY Gregorich, KE Mohar, MF Prussin, SG Lee, IY Oganessian, YT Ter-Akopian, GM Daniel, AV AF Sakhaee, M Zhu, SJ Gan, CY Zhu, LY Yan, LM Xu, RQ Jon, MG Jiang, Z Zhang, Z Hamilton, JH Ramayya, AV Babu, BRS Hwang, JK Ma, WC Komicki, J Cole, JD Aryaeinejad, R Drigert, MW Rasmussen, JO Stoyer, MA Chu, SY Gregorich, KE Mohar, MF Prussin, SG Lee, IY Oganessian, YT Ter-Akopian, GM Daniel, AV TI Collective band structures in neutron-rich odd-A Ce-145,Ce-147 nuclei SO HIGH ENERGY PHYSICS AND NUCLEAR PHYSICS-CHINESE EDITION LA Chinese DT Article DE nuclear structure; collective band; spontaneous fission ID OCTUPOLE CORRELATIONS; BARIUM ISOTOPES; DEFORMATION; FISSION; XE-139 AB Through study of the prompt gamma -rays emitted in the spontaneous fission of Cf-252, high spin states of neutron-rich odd-A Ce-145,Ce-147 nuclei have been investigated. The levels in Ce-147 have been extended. A collective band in Ce-145 have been identified for the first time. The results from the par tide rotor model calculations indicate that the yrast bands in 145Ce and 147Ce originate from nui(13/2) orbital coupling and the ground states of Ce-145 and Ce-147 originate from (Vh(9/2)circle times nuf(7/2)) and vh(9/2) configuration, respectively. No obvious octupole deformation was observed in these two isotopes, but a side band obtained in Ce-147 may show some octupole correlations. C1 Tsing Hua Univ, Dept Phys, Beijing 100084, Peoples R China. Vanderbilt Univ, Dept Phys, Nashville, TN 37235 USA. Mississippi State Univ, Dept Phys, Mississippi State, MS 39762 USA. Idaho Natl Engn Lab, Idaho Falls, ID 83415 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Joint Inst Nucl Res, Dubna 141980, Russia. RP Sakhaee, M (reprint author), Tsing Hua Univ, Dept Phys, Beijing 100084, Peoples R China. RI Jiang, Zhuo/E-3110-2010 NR 20 TC 1 Z9 1 U1 0 U2 3 PU SCIENCE PRESS PI BEIJING PA 16 DONGHUANGCHENGGEN NORTH ST, BEIJING 100717, PEOPLES R CHINA SN 0254-3052 J9 HIGH ENERG PHYS NUC JI High Energy Phys. Nucl. Phys.-Chin. Ed. PD NOV PY 2000 VL 24 IS 11 BP 1018 EP 1023 PG 6 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 373VN UT WOS:000165310900007 ER PT J AU Casey, D Stodolsky, M AF Casey, D Stodolsky, M TI On the shoulders of giants: Private sector leverages HGP successes - Data, technologies catalyze a new, high-profile life sciences industry SO HUMAN GENOME NEWS LA English DT Article C1 HGMIS, Oak Ridge, TN 37830 USA. US DOE, Washington, DC 20585 USA. RP Casey, D (reprint author), HGMIS, Oak Ridge, TN 37830 USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU HUMAN GENOME MANAGE INF SYSTEM PI OAK RIDGE PA OAK RIDGE NATIONAL LABORATORY, 1060 COMMERCE PARK, OAK RIDGE, TN 37830 USA SN 1050-6101 J9 HUM GENOME NEWS JI Hum. Genome News PD NOV PY 2000 VL 11 IS 1-2 BP 1 EP 3 PG 3 WC Biotechnology & Applied Microbiology; Genetics & Heredity SC Biotechnology & Applied Microbiology; Genetics & Heredity GA 385WP UT WOS:000166028400001 ER PT J AU Drell, D Adamson, A AF Drell, D Adamson, A TI Fast forward to 2020: What to expect in molecular medicine SO HUMAN GENOME NEWS LA English DT Article C1 US DOE, Washington, DC 20585 USA. HGMIS, Oak Ridge, TN 37830 USA. RP Drell, D (reprint author), US DOE, Washington, DC 20585 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU HUMAN GENOME MANAGE INF SYSTEM PI OAK RIDGE PA OAK RIDGE NATIONAL LABORATORY, 1060 COMMERCE PARK, OAK RIDGE, TN 37830 USA SN 1050-6101 J9 HUM GENOME NEWS JI Hum. Genome News PD NOV PY 2000 VL 11 IS 1-2 BP 13 EP 14 PG 2 WC Biotechnology & Applied Microbiology; Genetics & Heredity SC Biotechnology & Applied Microbiology; Genetics & Heredity GA 385WP UT WOS:000166028400016 ER PT J AU Symbalisty, EMD Roussel-Dupre, RA ReVelle, DO Suszcynsky, DM Yukhimuk, VA Taylor, MJ AF Symbalisty, EMD Roussel-Dupre, RA ReVelle, DO Suszcynsky, DM Yukhimuk, VA Taylor, MJ TI Meteor trails and columniform sprites SO ICARUS LA English DT Article; Proceedings Paper CT 7th International Asteroids, Comets, Meteors Conference (ACM 99) CY JUL 26-30, 1999 CL CORNELL UNIV, ITHACA, NEW YORK HO CORNELL UNIV DE meteors; Earth; geophysics; atmospheres structure ID RUNAWAY AIR BREAKDOWN; HIGH-ALTITUDE DISCHARGES; AIRGLOW IMAGE DATA; OPTICAL CHARACTERISTICS; STREAM ACTIVITY; RED SPRITES; STRATOSPHERE; EMISSIONS; MODEL; N2 AB A theoretical model of columniform sprites (or c-sprites), a distinctive class of high altitude, temporally brief optical emissions, is presented and compared to observations which extends earlier work (1998, E. M, D, Symbalisty, R, Roussel-Dupre, and V. Yukhimuk, EOS Transactions of the AGU 79, No. 45, p, F129) by making a strong connection with meteors, The key features of the model are: (1) an ambient conductivity profile that falls between a measured nighttime and a measured daytime conductivity; (2) an aerosol reduced conductivity in a trail from a meteor that passed through some time during the evening, and (3) a cloud-to-ground (hereafter CG) lightning stroke, with sufficient charge transfer, subsequent to and occurring within an hour of the development of the reduced conductivity trail. The model predicts a temporally brief column oh light resulting from the conventional breakdown of air in a strong electric field in the observed altitude range. For the case of a positive CG stroke the emissions are extinguished by the passage of a runaway electron beam. The electron beam is initiated by the same positive CG lightning stroke that allows the high altitude conventional breakdown to occur and propagates from the cloud tops to the ionosphere, Based on our modeling results, a negative CG lightning stroke, for the same amount of charge transfer, produces a column of light about twice as bright. The emissions are extinguished, in this case, by the ambient conductivity taking into account the increase due to the conventional breakdown of air. In both cases, for the CG lightning stroke parameters examined here, the simulated c-sprite emissions are brief and last less than 17 ms, or one CCD video field. (C) 2000 Academic Press. C1 Univ Calif Los Alamos Natl Lab, Grp EES 8, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Grp NIS 1, Los Alamos, NM 87545 USA. BGI, San Francisco, CA 94105 USA. Utah State Univ, Logan, UT 84322 USA. RP Symbalisty, EMD (reprint author), Univ Calif Los Alamos Natl Lab, Grp EES 8, POB 1663,MS F659, Los Alamos, NM 87545 USA. NR 47 TC 11 Z9 11 U1 0 U2 3 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD NOV PY 2000 VL 148 IS 1 BP 65 EP 79 DI 10.1006/icar.2000.6517 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 375UV UT WOS:000165420400008 ER PT J AU Jacobs, RR Scifres, DR AF Jacobs, RR Scifres, DR TI Recollections on the founding of Spectra Diode Labs, Inc. (SDL, Inc.) SO IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS LA English DT Article DE diode-pumped solid-state lasers; diode pumps for erbium amplifiers; high power semiconductor diode lasers AB Spectra Diode Labs, Inc. (now named SDL, Inc.) was officially established on April 1, 1983, as a joint venture by Spectra-Physics, Inc., and Xerox Corporation. It was the first significant commercial supplier of quality high-power semiconductor diode lasers for governmental and commercial applications. Accordingly, it helped pave the way for the "revolution" that has taken place in the laser industry in the use of high-power semiconductor diode lasers and the attendant derivative systems, diode-pumped solidstate lasers that are rapidly replacing traditional gas and flashlamp-pumped solid-state lasers for many applications. Additionally, the company has helped lead the burgeoning telecommunications market with, among other offerings, diode lasers that pump erbium-doped fiber amplifiers that form the heart of the WDM: telecom systems. As one measure of its success an offer was made on July 10, 2000, to acquire SDL, Inc., for $41 B which represents the largest high-technology takeover ever. Briefly reviewed here is the early history of SDL, Inc. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. SDL Inc, San Jose, CA 95134 USA. RP Jacobs, RR (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1077-260X J9 IEEE J SEL TOP QUANT JI IEEE J. Sel. Top. Quantum Electron. PD NOV-DEC PY 2000 VL 6 IS 6 BP 1228 EP 1230 DI 10.1109/2944.902171 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 407MP UT WOS:000167275600041 ER PT J AU Shen, YR AF Shen, YR TI Surface nonlinear optics: A historical perspective SO IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS LA English DT Article DE nonlinear optics; surfaces and interfaces; second harmonic generation; sum-frequency generation; sum-frequency vibrational spectroscopy; surface structures ID SUM-FREQUENCY-GENERATION; 2ND HARMONIC-GENERATION; AIR-WATER-INTERFACE; 2ND-HARMONIC GENERATION; VIBRATIONAL SPECTROSCOPY; MOLECULAR MONOLAYERS; LIQUID INTERFACE; SPECTRA; METAL; DESORPTION AB A historical review is given on the development of surface second-harmonic and sum-frequency generation and their applications as analytical tools to surface science. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NR 63 TC 37 Z9 38 U1 0 U2 14 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1077-260X EI 1558-4542 J9 IEEE J SEL TOP QUANT JI IEEE J. Sel. Top. Quantum Electron. PD NOV-DEC PY 2000 VL 6 IS 6 BP 1375 EP 1379 DI 10.1109/2944.902191 PG 5 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 407MP UT WOS:000167275600061 ER PT J AU Werfel, J Mitchell, M Crutchfield, JP AF Werfel, J Mitchell, M Crutchfield, JP TI Resource sharing and coevolution in evolving cellular automata SO IEEE TRANSACTIONS ON EVOLUTIONARY COMPUTATION LA English DT Letter DE cellular automata; cooperative systems; distributed decision making; genetic algorithms; pattern classification AB Coevolution, between a population of candidate solutions and a population of test cases, has received increasing attention as a promising biologically inspired method for improving the performance of evolutionary computation techniques. However, the results of studies of coevolution have been mixed. One of the seemingly more impressive results to date was the improvement via coevolution demonstrated by Juille and Pollack on evolving cellular automata to perform a classification task. Their Study, however, Like most other studies on coevolution, did not investigate the mechanisms giving rise to the observed improvements. In this paper, we probe more deeply into the reasons for these observed improvements and present empirical evidence that, in contrast to what was claimed by Juille and Pollack, much of the improvement seen was due to their "resource sharing" technique rather than to coevolution. We also present empirical evidence that resource sharing works, at least in part, by preserving diversity in the population. C1 MIT, Dept Elect Engn & Comp Sci, Cambridge, MA 02139 USA. Univ Calif Los Alamos Natl Lab, Biophys Grp, Los Alamos, NM 87545 USA. Santa Fe Inst, Santa Fe, NM 87501 USA. RP Werfel, J (reprint author), MIT, Dept Elect Engn & Comp Sci, Cambridge, MA 02139 USA. NR 20 TC 29 Z9 29 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 1089-778X J9 IEEE T EVOLUT COMPUT JI IEEE Trans. Evol. Comput. PD NOV PY 2000 VL 4 IS 4 BP 388 EP 393 PG 6 WC Computer Science, Artificial Intelligence; Computer Science, Theory & Methods SC Computer Science GA 379RF UT WOS:000165655700007 ER PT J AU Shin, WT Yiacoumi, S Tsouris, C Dai, S AF Shin, WT Yiacoumi, S Tsouris, C Dai, S TI A pulseless corona-discharge process for the oxidation of organic compounds in water SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID HIGH-VOLTAGE DISCHARGE; ELECTROSTATIC DISPERSION; NONCONDUCTIVE FLUIDS; CONDUCTIVE FLUIDS; AQUEOUS-SOLUTION; ELECTRIC-FIELDS; OZONE; DEGRADATION; ULTRASOUND; VIABILITY AB Ozone is widely used to deactivate microorganisms and remove organic contaminants in water industries. However, interest also exists in using radical species, which are stronger oxidants than ozone, in such processes. One means of producing radical species is by corona discharge. This work investigates the use of a novel pulseless corona-discharge system for the removal of organic substances. The method combines corona discharge with electrohydrodynamic spraying of oxygen, forming microbubbles. Experimental results show that pulseless corona discharge effectively removes organics, such as phenol and methylene blue, in deionized water. The corona-discharge method is demonstrated to be comparable to the direct use of ozone at a high applied voltage. The results also show that a minimum applied voltage exists for an effective operation of the corona-discharge method. In this work, the minimum applied voltage is approximately 4-4.5 kV over a 3-cm distance between the electrodes. The kinetic rate of phenol degradation in the reactor is modeled. Modeling results show that the dominant species of the pulseless corona-discharge reactor are hydroxyl radical and aqueous electron. Several radical species produced in the pulseless corona-discharge process are identified experimentally. The major species are hydroxyl radical, atomic hydrogen species, and ozone. C1 Georgia Inst Technol, Sch Civil & Environm Engn, Atlanta, GA 30332 USA. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. RP Tsouris, C (reprint author), Georgia Inst Technol, Sch Civil & Environm Engn, Atlanta, GA 30332 USA. RI Tsouris, Costas/C-2544-2016; Dai, Sheng/K-8411-2015 OI Tsouris, Costas/0000-0002-0522-1027; Dai, Sheng/0000-0002-8046-3931 NR 29 TC 35 Z9 40 U1 1 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 NOV PY 2000 VL 39 IS 11 BP 4408 EP 4414 DI 10.1021/ie0002374 PG 7 WC Engineering, Chemical SC Engineering GA 371RF UT WOS:000165191400051 ER PT J AU Weber, CF AF Weber, CF TI Calculation of Pitzer parameters at high ionic strengths SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID THERMODYNAMIC PROPERTIES; MINERAL SOLUBILITIES; NATURAL-WATERS; 25-DEGREES-C; SYSTEM; PREDICTION; ELECTROLYTES; EQUATIONS AB A technique is developed for univalent salts that allows calculation of activity coefficients at very high ionic strengths using solubility data. Pitzer parameters for binary solutions are extended to ionic strengths exceeding the salt solubility limits. Pitzer mixing parameters are obtained from solutions with ionic strengths much higher than the usual valid range for the Pitzer method. The method is demonstrated on several salt; systems at 25 degreesC. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Weber, CF (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA. NR 17 TC 9 Z9 9 U1 1 U2 8 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 NOV PY 2000 VL 39 IS 11 BP 4422 EP 4426 DI 10.1021/ie000411o PG 5 WC Engineering, Chemical SC Engineering GA 371RF UT WOS:000165191400053 ER PT J AU Aceves, SM Martinez-Frias, J Garcia-Villazana, O AF Aceves, SM Martinez-Frias, J Garcia-Villazana, O TI Analytical and experimental evaluation of insulated pressure vessels for cryogenic hydrogen storage SO INTERNATIONAL JOURNAL OF HYDROGEN ENERGY LA English DT Article AB Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LH2) or ambient-temperature compressed hydrogen (CH2). These vessels offer the advantages of LH2 tanks (low weight and volume), with reduced disadvantages (fuel flexibility, lower energy requirement for hydrogen liquefaction and reduced evaporative losses). The work described here is directed to verify that commercially available pressure vessels can be safely used to store LH2. The use of commercially available pressure vessels significantly reduces the cost and complexity of the insulated pressure vessel development effort. This paper describes a series of tests that have been done with aluminum-lined, fiber-wrapped vessels to evaluate the damage caused by low temperature operation. All analyses and experiments to date indicate that no significant damage has resulted. Required future tests are described, which will prove that no technical barriers exist to the safe use of aluminum-fiber vessels at cryogenic temperatures. Published by Elsevier Science Ltd on behalf of the International Association for Hydrogen Energy. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Ctr Ingn & Desarrollo Ind, Queretaro, Qro, Mexico. Univ Guanajuato, FIMEE, Salamanca, Gto, Mexico. RP Aceves, SM (reprint author), Univ Calif Lawrence Livermore Natl Lab, 7000 East Ave,L-641, Livermore, CA 94551 USA. RI aceves, salvador/G-9052-2011 OI aceves, salvador/0000-0001-5687-7256 NR 24 TC 33 Z9 35 U1 1 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0360-3199 J9 INT J HYDROGEN ENERG JI Int. J. Hydrog. Energy PD NOV PY 2000 VL 25 IS 11 BP 1075 EP 1085 DI 10.1016/S0360-3199(00)00016-1 PG 11 WC Chemistry, Physical; Electrochemistry; Energy & Fuels SC Chemistry; Electrochemistry; Energy & Fuels GA 355RD UT WOS:000089397900008 ER PT J AU Levesque, S Ciureanu, M Roberge, R Motyka, T AF Levesque, S Ciureanu, M Roberge, R Motyka, T TI Hydrogen storage for fuel cell systems with stationary applications - I. Transient measurement technique for packed bed evaluation SO INTERNATIONAL JOURNAL OF HYDROGEN ENERGY LA English DT Article DE hydrogen storage; transient measurement technique ID METAL AB Data are presented on a metal hydride storage unit used as a hydrogen source for a 500 W fuel cell power supply system powering the electrical components of a gas furnace. The investigated packed bed had special design features for the internal heat transfer optimization: the hydride material was packed into Al foam, and an inner coaxial U-shaped tube enabled removal of heat by a heat transfer agent. This design enables recuperating heat from the gas furnace, by circulating the hot exhaust through the U-shaped tube, to compensate for the heat absorbed during hydrogen desorption, A transient measurement technique is used to evaluate the heat transfer properties of the storage unit. The method is based on a combination of transient temperature measurements, which provides data on heat exchange properties of the storage unit, as well as an estimate of the hydriding enthalpy Delta H for hydrogen desorption. In the absence of heating, the discharge is controlled by the rate of heat transfer between the container walls and the ambient atmosphere. The method provides a simple procedure for evaluating the value of the maximum flow of hydrogen which can be released, so that the entire amount of hydrogen stored in the packed bed can be discharged. When a heating agent is circulated through the U-shaped tube in the storage unit, the maximum discharge rate can be increased by an order of magnitude and the heat exchange with the ambient atmosphere becomes un-important. (C) 2000 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved. C1 H Power Enterprises Canada, Ville St Laurent, PQ H4R 1V8, Canada. Westinghouse Savannah River Co, Savannah River Technol Ctr, Aiken, SC 29808 USA. RP Ciureanu, M (reprint author), H Power Enterprises Canada, 1069 Begin St, Ville St Laurent, PQ H4R 1V8, Canada. NR 8 TC 40 Z9 40 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0360-3199 J9 INT J HYDROGEN ENERG JI Int. J. Hydrog. Energy PD NOV PY 2000 VL 25 IS 11 BP 1095 EP 1105 DI 10.1016/S0360-3199(00)00023-9 PG 11 WC Chemistry, Physical; Electrochemistry; Energy & Fuels SC Chemistry; Electrochemistry; Energy & Fuels GA 355RD UT WOS:000089397900010 ER PT J AU Tolle, DA Evers, DP Vigon, BW Sheehan, JJ AF Tolle, Duane A. Evers, David P. Vigon, Bruce W. Sheehan, John J. TI Streamlined LCA of Soy-Based Ink Printing SO INTERNATIONAL JOURNAL OF LIFE CYCLE ASSESSMENT LA English DT Article DE Impact categories; LCI; LCIA; Life Cycle Impact Assessment (LCIA); Life Cycle Inventory (LCI); lithography; sheetfed printing; soy-based ink; soybean oil AB This study provides a benchmark of the life cycle environmental impact characteristics associated with a typical soy-based ink used for sheetfed lithographic printing. The scope included a streamlined Life Cycle Inventory (LCI) and Impact Assessment (LCIA). Materials, processes, and life cycle stages that are the same between different printing inks, or were less than one percent by mass of the printing system input materials, were excluded. The LCIA included identification of specific processes in the life cycle of soy-based ink printing that make the greatest contribution to the overall environmental hazard potential in 13 impact categories for the baseline printing system selected. The LCIA approach included both regional scaling for areas that differ in sensitivity to certain impact indicators and normalization against a reference value. Reduction in the use of tall oil rosin and switching from conventional to low or no-till farming appear to be promising opportunities for reducing the environmental hazard potential. C1 [Tolle, Duane A.; Evers, David P.; Vigon, Bruce W.] Battelle Mem Inst, Life Cycle Management Grp, Columbus, OH 43201 USA. [Sheehan, John J.] Natl Renewable Energy Lab, Biotechnol Ctr Fuels & Chem, Golden, CO 80401 USA. RP Tolle, DA (reprint author), Battelle Mem Inst, Life Cycle Management Grp, 505 King Ave, Columbus, OH 43201 USA. EM tolled@battelle.org RI Sheehan, John/O-7042-2014 FU Iowa Soybean Promotion Board (through the National Soy Ink Information Center); Illinois Soybean Checkoff Board FX Funding for this project was provided jointly by the Iowa Soybean Promotion Board (through the National Soy Ink Information Center) and the Illinois Soybean Checkoff Board. Both Kirk Leeds and Jo Patterson with the Iowa Soybean Association provided guidance for the study. The authors would like to thank the GATF for technical assistance in defining the generic printing system and the five GATF member print shops that supplied inventory data. NREL provided two significant inventory modules on soybean growing and oil extraction. Derek R. Augood assisted in determining process information and inventory data for many of the intermediate materials. Wilson Cunningham provided contacts with many of the manufacturers of printing materials. Thomas E. Rice, Flint Ink Corporation, provided a generic formula for soy-based ink. Finally, the authors are particularly grateful to the external critical reviewers (Dr. J. William Owens from Procter & Gamble and Dr. William Rusterholz from Sun Chemical), who provided recommendations to improve the original report for compliance under the ISO 14040 series. NR 21 TC 0 Z9 0 U1 2 U2 7 PU SPRINGER HEIDELBERG PI HEIDELBERG PA TIERGARTENSTRASSE 17, D-69121 HEIDELBERG, GERMANY SN 0948-3349 EI 1614-7502 J9 INT J LIFE CYCLE ASS JI Int. J. Life Cycle Assess. PD NOV PY 2000 VL 5 IS 6 BP 374 EP 384 DI 10.1065/lca2000.11.040 PG 11 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA V32UW UT WOS:000208977100010 ER PT J AU Tran, TN Chyu, MC Wambsganss, MW France, DM AF Tran, TN Chyu, MC Wambsganss, MW France, DM TI Two-phase pressure drop of refrigerants during flow boiling in small channels: an experimental investigation and correlation development SO INTERNATIONAL JOURNAL OF MULTIPHASE FLOW LA English DT Article DE two-phase pressure drop; small channels; refrigerants; correlations AB Two-phase flow pressure drop measurements were made during a phase-change heat transfer process with three refrigerants (R-134a, R-12, and R-113) at six different pressures ranging from 138 to 856 kPa, and in two sizes of round tubes (2.46 and 2.92 mm inside diameters) and one rectangular channel (4.06 x 1.7 mm). The data were compared with those from large tubes under similar conditions, and state-of-the-art correlations were evaluated using the R-134a data. The state-of-the-art large-tube correlations failed to satisfactorily predict the experimental data, The data were used to develop a new correlation for two-phase pressure drop during flow boiling in small channels. The correlation was then tested against the experimental data for the three refrigerants; the error was +/- 20%. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. Texas Tech Univ, Dept Mech Engn, Lubbock, TX 79409 USA. Univ Illinois, Dept Mech Engn, Chicago, IL 60607 USA. RP Tran, TN (reprint author), Argonne Natl Lab, Div Energy Technol, 9700 S Cass Ave,Bldg 335, Argonne, IL 60439 USA. NR 18 TC 155 Z9 167 U1 1 U2 21 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0301-9322 J9 INT J MULTIPHAS FLOW JI Int. J. Multiph. Flow PD NOV PY 2000 VL 26 IS 11 BP 1739 EP 1754 DI 10.1016/S0301-9322(99)00119-6 PG 16 WC Mechanics SC Mechanics GA 354JC UT WOS:000089325400001 ER PT J AU Massoudi, M Johnson, G AF Massoudi, M Johnson, G TI On the flow of a fluid-particle mixture between two rotating cylinders, using the theory of interacting continua SO INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS LA English DT Article DE continuum mechanics; multiphase flows; granular materials; Couette flow ID COHESIONLESS GRANULAR-MATERIALS; STRESS CALCULATIONS; ASSEMBLIES; MECHANICS; SPHERES; MOTION; MEDIA; SHEAR; BEDS; SLOW AB Mixture theory is used to develop a model for a flowing mixture of solid particulates and a fluid. Equations describing the flow of a two-component mixture consisting of a Newtonian fluid and a granular solid are derived. These relatively general equations are then reduced to a system of coupled ordinary differential equations describing Couette flow between concentric rotating cylinders. The resulting boundary value problem is solved numerically and representative results are presented. Published by Elsevier Science Ltd. C1 Fed Energy Technol Ctr, US Dept Energy, Pittsburgh, PA 15236 USA. Univ Pittsburgh, Dept Mech Engn, Pittsburgh, PA 15261 USA. RP Massoudi, M (reprint author), Fed Energy Technol Ctr, US Dept Energy, POB 10940, Pittsburgh, PA 15236 USA. NR 70 TC 9 Z9 9 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0020-7462 J9 INT J NONLINEAR MECH JI Int. J. Non-Linear Mech. PD NOV PY 2000 VL 35 IS 6 BP 1045 EP 1058 DI 10.1016/S0020-7462(99)00078-5 PG 14 WC Mechanics SC Mechanics GA 324UN UT WOS:000087639900007 ER PT J AU Zhang, QM Cai, HM Zhang, ZY AF Zhang, QM Cai, HM Zhang, ZY TI Ab initio studies of Ge addimers on the Si(100) surface SO INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY LA English DT Article; Proceedings Paper CT 40th Annual Sanibel Symposium CY FEB 26-MAR 03, 2000 CL ST AUGUSTINE, FL SP IBM Corp, HyperCube Inc, Univ Florida DE Si(100) surface; Si/Ge heterostructure; first-principles molecular dynamics; simulated STM image ID SI AD-DIMERS; SCANNING-TUNNELING-MICROSCOPY; DIFFUSION-BARRIERS; ENERGETICS; DYNAMICS; SI(001); ADATOM; GROWTH; STEPS AB The atomic and electronic structures of Ge dimers adsorbed on top of a Si(100) flat surface has been investigated by first-principles molecular dynamics method. Four high-symmetry configurations have been considered and thoroughly relaxed. The most stable configuration for Ge dimers is found to be on the trough, in the middle of, and parallel to the substrate Si dimers. These results are consistent with recent experimental studies of the system using the scanning tunneling microscopy. (C) 2000 John Wiley & Sons, Inc. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ Texas, Dept Phys, Arlington, TX 76019 USA. Univ Tennessee, Dept Phys, Knoxville, TN USA. RP Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. EM zhangz@ornl.gov NR 21 TC 1 Z9 1 U1 2 U2 4 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0020-7608 EI 1097-461X J9 INT J QUANTUM CHEM JI Int. J. Quantum Chem. PD NOV-DEC PY 2000 VL 80 IS 4-5 BP 708 EP 712 DI 10.1002/1097-461X(2000)80:4/5<708::AID-QUA20>3.0.CO;2-2 PG 5 WC Chemistry, Physical; Mathematics, Interdisciplinary Applications; Physics, Atomic, Molecular & Chemical SC Chemistry; Mathematics; Physics GA 370DP UT WOS:000165108300019 ER PT J AU Boettger, JC Ray, AK AF Boettger, JC Ray, AK TI All-electron LCGTO calculations for uranium dioxide SO INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY LA English DT Article; Proceedings Paper CT 40th Annual Sanibel Symposium CY FEB 26-MAR 03, 2000 CL ST AUGUSTINE, FL SP IBM Corp, HyperCube Inc, Univ Florida DE uranium dioxide; LCGTO; density functional; electronic structure; spin-orbit ID DENSITY-FUNCTIONAL THEORY; UO2; PHOTOEMISSION; INSULATORS; SOLIDS; ENERGY; NIO AB The linear combinations of Gaussian-type orbitals-fitting function (LCGTO-FF) technique is used to study the zero-pressure properties of crystalline uranium dioxide, a prototypical heavy element bearing Mott-Hubbard insulator. The effects of several common approximations are examined: (1) scalar vs, full relativity; (2) paramagnetic vs. spin polarized; and (3) local density approximation (LDA) vs, generalized-gradient approximation (GGA). UO2 is incorrectly predicted to be a metal for all approximations considered here, as expected for a Mott-Hubbard insulator. The lattice constant and bulk modulus obtained using the highest level approximations are, however, in excellent agreement with experiment. This suggests that the strong correlation effects that are generally believed to produce the observed band gap do not have a significant impact on the binding properties of UO2, contrary to the results of recent LDA+U calculations. (C) 2000 John Wiley & Sons, Inc. C1 Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Texas, Dept Phys, Arlington, TX 76019 USA. RP Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. EM jn@lanl.gov NR 42 TC 33 Z9 33 U1 0 U2 4 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0020-7608 EI 1097-461X J9 INT J QUANTUM CHEM JI Int. J. Quantum Chem. PD NOV-DEC PY 2000 VL 80 IS 4-5 BP 824 EP 830 DI 10.1002/1097-461X(2000)80:4/5<824::AID-QUA30>3.3.CO;2-Q PG 7 WC Chemistry, Physical; Mathematics, Interdisciplinary Applications; Physics, Atomic, Molecular & Chemical SC Chemistry; Mathematics; Physics GA 370DP UT WOS:000165108300029 ER PT J AU Ritchie, B Weatherford, CA AF Ritchie, B Weatherford, CA TI Numerical solution of the time-dependent Schrodinger equation for continuum states SO INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY LA English DT Article; Proceedings Paper CT 40th Annual Sanibel Symposium CY FEB 26-MAR 03, 2000 CL ST AUGUSTINE, FLORIDA SP IBM Corp, HyperCube Inc, Univ Florida DE wave packets; electron scattering; time-dependent Schrodinger equation; continuum states ID ELECTRON-IMPACT IONIZATION; WAVE-PACKET THEORY; HYDROGEN SCATTERING; COUPLING METHOD; MODEL AB The time-dependent Schrodinger equation is solved numerically by using fast-Fourier transforms (FFTs) to evaluate the integrating factor e((i/2)del2(t-t')) in the integral form of the Schrodinger equation. The need for boundary conditions at grid boundaries is obviated provided the grid box is large enough that V psi, on which the integrating factor operates, is bounded within it. This means that psi can be represented as appropriately unbounded rather than as a wave packet confined within the box, whose spreading over time to the grid boundaries places practical Limits on the duration of the collision. This development means that numerical simulations for electron or positron scattering can be carried out at lower momenta k < 1 than is currently practical using a wave packet description. (C) 2000 John Wiley & Sons, Inc. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Florida A&M Univ, Dept Phys, Tallahassee, FL 32307 USA. RP Weatherford, CA (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 9 TC 2 Z9 2 U1 0 U2 0 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0020-7608 J9 INT J QUANTUM CHEM JI Int. J. Quantum Chem. PD NOV-DEC PY 2000 VL 80 IS 4-5 BP 934 EP 941 DI 10.1002/1097-461X(2000)80:4/5<934::AID-QUA42>3.0.CO;2-O PG 8 WC Chemistry, Physical; Mathematics, Interdisciplinary Applications; Physics, Atomic, Molecular & Chemical SC Chemistry; Mathematics; Physics GA 370DP UT WOS:000165108300041 ER PT J AU Skurski, P Gutowski, M Simons, J AF Skurski, P Gutowski, M Simons, J TI How to choose a one-electron basis set to reliably describe a dipole-bound anion SO INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY LA English DT Article; Proceedings Paper CT 40th Annual Sanibel Symposium CY FEB 26-MAR 03, 2000 CL ST AUGUSTINE, FLORIDA SP IBM Corp, HyperCube Inc, Univ Florida DE basis sets; anions; dipole-bond ID GROUND-STATE; CORRELATED CALCULATIONS; POLAR-MOLECULES; CONVERGENCE; COMPLEXES; WATER; ATOMS; ENERGETICS; CLUSTERS; BINDING AB The problem of choosing appropriate atomic orbital basis sets for ab initio calculations on dipole-bound anions has been examined. Such basis sets are usually constructed as combination of a standard valence-type basis, designed to describe the neutral molecular core, and an extra diffuse set designed to describe the charge distribution of the extra electron. As part of the present work, it has been found that the most commonly used valence-type basis sets (e.g., 6-31++G** or 6-311+G**), when so augmented, are subject to unpredictable under- or overestimating electron binding energies for dipole-bound anions. Whereas, when the aug-cc-pVDZ, aug-cc-pVTZ [or other medium-size polarized (MSP) basis sets] are so augmented, more reliable binding energies are obtained especially when the electron binding energy is calculated at the CCSD(T) level of theory. The issue of designing and centering the extra diffuse basis functions for the excess electron has also been studied, and our findings are discussed here. (C) 2000 John Wiley & Sons, Inc. C1 Univ Utah, Dept Chem, Henry Eyring Ctr Theoret Chem, Salt Lake City, UT 84112 USA. Univ Gdansk, Dept Chem, PL-80952 Gdansk, Poland. Pacific NW Natl Lab, Richland, WA 99352 USA. RP Simons, J (reprint author), Univ Utah, Dept Chem, Henry Eyring Ctr Theoret Chem, Salt Lake City, UT 84112 USA. NR 32 TC 106 Z9 106 U1 1 U2 4 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0020-7608 J9 INT J QUANTUM CHEM JI Int. J. Quantum Chem. PD NOV-DEC PY 2000 VL 80 IS 4-5 BP 1024 EP 1038 DI 10.1002/1097-461X(2000)80:4/5<1024::AID-QUA51>3.3.CO;2-G PG 15 WC Chemistry, Physical; Mathematics, Interdisciplinary Applications; Physics, Atomic, Molecular & Chemical SC Chemistry; Mathematics; Physics GA 370DP UT WOS:000165108300050 ER PT J AU Watson, CA Chang-Liu, CM Woloschak, GE AF Watson, CA Chang-Liu, CM Woloschak, GE TI Modulation of calmodulin by UV and X-rays in primary human endothelial cell cultures SO INTERNATIONAL JOURNAL OF RADIATION BIOLOGY LA English DT Article ID IONIZING-RADIATION; GENE-EXPRESSION; MESSENGER-RNA; INTRACELLULAR CALCIUM; DNA-DAMAGE; SUPPRESSION; APOPTOSIS; GROWTH; CYCLE; G(1) AB Purpose: Previous studies by the present authors and others have shown that the expression of many genes is modulated by radiation. The purpose of this study is to identify additional genes that are affected by UV and X-radiation. Identification of specific genes affected by radiation may allow the determination of pathways important in radiation responses as well as an examination of transcriptional elements that are involved in the process. Materials and methods: A modified differential display approach coupled with sequencing was used to identify genes that are modulated in response to UV and ionizing radiation, and Northern blot analysis was used to confirm specific gene modulation. Results: Treatment of human primary umbilical vein endothelial cells with UV radiation resulted in the differential expression of several genes. Sequencing of the bands revealed that one of these was calmodulin. There was a 30% reduction in accumulation of calmodulin-specific mRNA 1 h post UV exposure, and a 50% decrease 3 h after treatment. X-rays also repressed accumulation of calmodium mRNA. Radiation exposure of HeLa cells also resulted in a decrease in expression of this gene. Conclusions : UV and ionizing radiations cause a decrease in accumulation of calmodulin transcripts in the first 1-3 h following exposure. Repression of calmodium mRNA levels may be one mechanism of stress-induced intracellular Ca2+ modulation. C1 Argonne Natl Lab, Biosci Div, Argonne, IL 60439 USA. Roosevelt Univ, Sch Sci & Math, Chicago, IL 60605 USA. RP Woloschak, GE (reprint author), Argonne Natl Lab, Biosci Div, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Woloschak, Gayle/A-3799-2017 OI Woloschak, Gayle/0000-0001-9209-8954 FU NCI NIH HHS [CA73042, CA81375]; NIEHS NIH HHS [ES 07141] NR 49 TC 8 Z9 9 U1 0 U2 3 PU TAYLOR & FRANCIS LTD PI LONDON PA 11 NEW FETTER LANE, LONDON EC4P 4EE, ENGLAND SN 0955-3002 J9 INT J RADIAT BIOL JI Int. J. Radiat. Biol. PD NOV PY 2000 VL 76 IS 11 BP 1455 EP 1461 PG 7 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 371AG UT WOS:000165155000003 PM 11098848 ER PT J AU Ryynanen, PM Kortesniemi, M Coderre, JA Diaz, AZ Hiismaki, P Savolainen, SE AF Ryynanen, PM Kortesniemi, M Coderre, JA Diaz, AZ Hiismaki, P Savolainen, SE TI Models for estimation of the B-10 concentration after BPA-fructose complex infusion in patients during epithermal neutron irradiation in BNCT SO INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS LA English DT Article DE BNCT; glioma; boronophyenylanine; kinetics; modeling ID SULFHYDRYL BORON HYDRIDE; HIGH-GRADE GLIOMAS; CAPTURE THERAPY; GLIOBLASTOMA-MULTIFORME; P-BORONOPHENYLALANINE; BIODISTRIBUTION; RAT; ASTROCYTOMA; FACILITY; MRI AB Purpose: To create simple and reliable models for clinical practice for estimating the blood B-10 time-concentration curve after p-boronophenylalanine fructose complex (BPA-F) infusion in patients during neutron irradiation in boron neutron capture therapy (BNCT), Methods and Materials: BPA-F (290 mg BPA/kg body weight) was infused i.v. during two hours to 10 glioblastoma multiforme patients. Blood samples were collected during and after the infusion. Compartmental models and bi-exponential function fit were constructed based on the B-10 blood time-concentration curve. The constructed models were tested with data from six additional patients who received various amounts of infused BPA-F and data from one patient who received a one-hour infusion of 170 mg BPA/kg body weight. Results: The resulting open two-compartment model and bi-exponential function estimate the clearance of B-10 after 290 mg BPA/kg body weight infusion from the blood with satisfactory accuracy during the first irradiation field (1 ppm, i.e., 7%). The accuracy of the two models in predicting the clearance of B-10 during the second irradiation field are for two-compartment model 1.0 ppm (8%) and 0.2 ppm (2%) for bi-exponential function. The models predict the average blood B-10 concentration with an increasing accuracy as more data points are available during the treatment. Conclusion: By combining the two models, a robust and practical modeling tool is created for the estimation of the B-10 concentration in blood after BPA-F infusion. (C) 2000 Elsevier Science Inc. C1 Univ Helsinki, Dept Phys, Helsinki, Finland. Univ Helsinki, Cent Hosp, Dept Radiol, Helsinki, Finland. Univ Helsinki, Cent Hosp, Dept Diagnost, Helsinki, Finland. Univ Helsinki, Cent Hosp, Clin Res Inst, Helsinki, Finland. Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. VTT Chem Technol, Tech Res Ctr, Espoo, Finland. RP Savolainen, SE (reprint author), Univ Helsinki Hosp, Dept Radiol, POB 380, FIN-00029 Hus, Finland. NR 38 TC 26 Z9 27 U1 0 U2 4 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0360-3016 J9 INT J RADIAT ONCOL JI Int. J. Radiat. Oncol. Biol. Phys. PD NOV 1 PY 2000 VL 48 IS 4 BP 1145 EP 1154 DI 10.1016/S0360-3016(00)00766-5 PG 10 WC Oncology; Radiology, Nuclear Medicine & Medical Imaging SC Oncology; Radiology, Nuclear Medicine & Medical Imaging GA 372NB UT WOS:000165238800030 PM 11072174 ER PT J AU Blakely, EA Bjornstad, KA Chang, PY McNamara, MP Chang, E Aragon, G Lin, SP Lui, G Polansky, JR AF Blakely, EA Bjornstad, KA Chang, PY McNamara, MP Chang, E Aragon, G Lin, SP Lui, G Polansky, JR TI Growth and differentiation of human lens epithelial cells in vitro on matrix SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Article ID ALPHA-B-CRYSTALLIN; GENE-EXPRESSION; RAT LENS; CHICKEN LENS; FIBER DIFFERENTIATION; TRANSGENIC MICE; DONOR AGE; CULTURE; PROLIFERATION; INVITRO AB PURPOSE. To characterize the growth and maturation of nonimmortalized human lens epithelial (HLE) cells grown in vitro. METHODS. HLE cells, established from 18-week prenatal lenses, were maintained on bovine corneal endothelial (BCE) extracellular matrix (ECM) in medium supplemented with basic fibroblast growth factor (FGF-2). The identity, growth, and differentiation of the cultures were characterized by karyotyping, cell morphology, and growth kinetics studies, reverse transcription-polymerase chain reaction (RT-PCR), immunofluorescence, and Western blot analysis. RESULTS. HLE cells had a male, human diploid (2N = 46) karyotype. The population-doubling time of exponentially growing cells was 24 hours. After 15 days in culture, cell morphology changed, and lentoid formation was evident. Reverse transcription-polymerase chain reaction (RT-PCR) indicated expression of alphaA- and beta B2-crystallin, fibroblast growth factor receptor 1 (FGFR1), and major intrinsic protein (MIP26) in exponential growth. Western analyses of protein extracts show positive expression of three immunologically distinct classes of crystallin proteins (alphaA-, alphaB-, and beta B2-crystallin) with time in culture. By Western blot analysis, expression of p57(KIP2), a known marker of terminally differentiated fiber cells, was detectable in exponential cultures, and levels increased after confluence. MIP2G and gamma -crystallin protein expression was detected in confluent cultures, by using immunofluorescence, but not in exponentially growing cells. CONCLUSIONS. HLE cells can be maintained for up to 4 months on ECM derived from BCE cells in medium containing FGF-2. With time in culture, the cells demonstrate morphologic characteristics of, and express protein markers for, lens fiber cell differentiation. This in vitro model will be useful for investigations of radiation-induced cataractogenesis and other studies of lens toxicity. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Cellrex, San Francisco, CA USA. Univ Calif San Francisco, Dept Ophthalmol, Cellular Pharmacol Lab, San Francisco, CA 94143 USA. RP Blakely, EA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, 1 Cyclotron Rd,MS 70A-1118, Berkeley, CA 94720 USA. FU NEI NIH HHS [EY-10737, EY-02477] NR 58 TC 26 Z9 26 U1 0 U2 4 PU ASSOC RESEARCH VISION OPHTHALMOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD NOV PY 2000 VL 41 IS 12 BP 3898 EP 3907 PG 10 WC Ophthalmology SC Ophthalmology GA 369LH UT WOS:000165066400033 PM 11053292 ER PT J AU Prakash, J Redey, L Vissers, DR DeGruson, J AF Prakash, J Redey, L Vissers, DR DeGruson, J TI Effect of sodium iodide additive on the electrochemical performance of sodium/nickel chloride cells SO JOURNAL OF APPLIED ELECTROCHEMISTRY LA English DT Article DE batteries; dynamic performance; electric vehicle; iodine; nickel chloride ID BATTERY AB The effect of sodium iodide and sulfur additives on the performance of Na/beta''-alumina/NaAlCl4/NiCl2/Ni cells was investigated in quasi-sealed laboratory research cells (0.5-1.0 Ah capacity) and in sealed full-size cells (4 Ah capacity). It was found that sodium iodide additive especially in combination with sulfur in Na/NiCl2 cells significantly increases the usable capacity and reduces the impedance of the Na/NiCl2 cells. It is proposed that the use of sodium iodide enhances the energy and power performance of the NiCl2 electrode by two different mechanisms. The first mechanism, iodide ion doping of the anodically formed solid NiCl2, is dominant at potentials lower than that of iodine evolution. The doping effect of the iodide ions produces a higher-capacity, lower-impedance NiCl2 layer on the positive electrode. The second mechanism, anodic formation of very reactive iodine species, is effective when the cell is cycled through the iodine evolution potential range (2.8-3.1 V vs Na). During this process, the dissolved iodine species improve electrode kinetics through liquid-phase mass transport. Use of the sodium iodide additive is safe in sealed cells, causing no over-pressurizing problems. A maximum pressure increase of only 10 kPa was detected by a pressure sensor during severe overcharge tests. C1 IIT, Ctr Electrochem Sci & Engn, Chicago, IL 60616 USA. IIT, Dept Environm Chem & Engn, Chicago, IL 60616 USA. Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. Eagle Picher Ind Inc, Joplin, MO 64801 USA. RP Prakash, J (reprint author), IIT, Ctr Electrochem Sci & Engn, Chicago, IL 60616 USA. NR 16 TC 5 Z9 5 U1 5 U2 21 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0021-891X J9 J APPL ELECTROCHEM JI J. Appl. Electrochem. PD NOV PY 2000 VL 30 IS 11 BP 1229 EP 1233 DI 10.1023/A:1026539607417 PG 5 WC Electrochemistry SC Electrochemistry GA 377HB UT WOS:000165507100004 ER PT J AU O'Steen, LB AF O'Steen, LB TI Numerical simulation of nocturnal drainage flows in idealized valley-tributary systems SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID DEEP VALLEY; ENERGY BUDGET; DISPERSION; MODEL; TURBULENCE; VELOCITY; FLUXES; WINDS; MASS AB Numerical simulations of nocturnal drainage flow and transport in idealized valley-tributary systems are compared with the Atmospheric Science in Complex Terrain (ASCOT) meteorological field data and tracer studies from the Brush Creek valley of western Colorado. Much of the general valley-tributary flow behavior deduced from observations is qualitatively reproduced in the numerical results. The spatially complex, unsteady nature of the tributary flow found in the field data is also seen in the simulations. Oscillations in the simulated tributary Row are similar to some field observations. However, observed oscillations in the valley flow at the mouth of the tributary could not be reproduced in the numerical results. Thus, hypotheses of strongly coupled valley-tributary flow oscillations, based on field data, cannot be supported by these simulations. Along-valley mass flux calculations based on model results for the valley-tributary system indicate an increase of 5%-10% over a valley without a tributary. Enhanced valley mass fluxes were found from 8 km above the tributary to almost the valley mouth. However, the valley mass fluxes for topography with and without a tributary were nearly equal at the valley outflow. ASCOT field data suggested a tributary mass how contribution of 5%-15% for a Brush Creek tributary of similar drainage area to the model tributary employed here. Numerical simulations of transport in the nocturnal valley-tributary flow strongly support ASCOT tracer studies in the Pack Canyon tributary of Brush Creek. These results suggest that the valley-tributary interaction can significantly increase plume dispersion under stable conditions. Overall, the simulation results presented here indicate that simple terrain geometries are able to capture many of the salient features of drainage flow in real valley-tributary systems. C1 Westinghouse Savannah River Co, Savannah River Technol Ctr, Aiken, SC 29808 USA. RP O'Steen, LB (reprint author), Westinghouse Savannah River Co, Savannah River Technol Ctr, Bldg 773-A, Aiken, SC 29808 USA. NR 25 TC 5 Z9 5 U1 0 U2 0 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 NOV PY 2000 VL 39 IS 11 BP 1845 EP 1860 DI 10.1175/1520-0450(2000)039<1845:NSONDF>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 378QF UT WOS:000165594500005 ER PT J AU Bhattacharyya, S Lubbe, M Richter, F AF Bhattacharyya, S Lubbe, M Richter, F TI Near edge x-ray absorption fine structure of thermally annealed amorphous nitrogenated carbon films SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID CATHODIC ARC DEPOSITION; NITRIDE FILMS; NEAR-EDGE; THIN-FILMS; STABILITY; SPECTROSCOPY; BETA-C3N4; REDUCTION AB The change of structure of tetrahedral amorphous carbon (ta-C) films after nitrogen incorporation, particularly at a high concentration, was studied by near edge x-ray absorption fine structure (NEXAFS) spectroscopy and it was found to be very close to pyridine. The pi* peak at the N K (nitrogen K) edge was decomposed into three components corresponding to different resonances. From a detailed analysis of N K edge by NEXAFS spectroscopy it was revealed that as the nitrogen concentration in the films increases, the sigma*/pi* intensity ratio decreases, indicating that there is an increase of the amount of C=N relative to the C-N bonds. By thermal annealing at different temperatures, up to 800 degrees C, the nitrogen concentration in the films is reduced. Intensity as well as the position of the pi* peak at the C K edge changed with annealing temperature. At the same time, a decrease of the intensity of the pi* peak at the N K edge and a very interesting change of the relative intensities of the three split components of this pi* peak have been observed. The possible changes of structure of nitrogenated carbon films by annealing and thermal stability of the films have been thoroughly emphasized. (C) 2000 American Institute of Physics. [S0021-8979(00)09422-6]. C1 TU Chemnitz, Inst Phys, D-09107 Chemnitz, Germany. RP Bhattacharyya, S (reprint author), Argonne Natl Lab, MSD CHM, Bldg 200,9700 S Cass Ave, Argonne, IL 60439 USA. EM somnath@anl.gov RI Bhattacharyya, Somnath/M-1867-2015 OI Bhattacharyya, Somnath/0000-0002-6435-7864 NR 31 TC 28 Z9 28 U1 0 U2 8 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD NOV 1 PY 2000 VL 88 IS 9 BP 5043 EP 5049 AR PII [S0021-8979(00)09422-6] DI 10.1063/1.1318389 PG 7 WC Physics, Applied SC Physics GA 363BL UT WOS:000089813800017 ER PT J AU Lim, SH Shindo, D AF Lim, SH Shindo, D TI Defects and interfaces in an epitaxial ZnO/LiTaO3 heterostructure SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID CHEMICAL-VAPOR-DEPOSITION; RESOLUTION ELECTRON-MICROSCOPY; ZNO THIN-FILMS; STACKING-FAULTS; GAN; SAPPHIRE; CRYSTALS AB ZnO films were grown on a (01 (1) over bar 2) r-plane LiTaO3 substrate by electron cyclotron resonance-assisted molecular-beam epitaxy. The detailed structures of the interface and defects are investigated by high-resolution electron microscopy and image simulation. The epitaxial relationship was found to be [0001](ZnO)parallel to[0 (1) over bar 11](LiTaO3) and (11 (2) over bar 0)(ZnO)parallel to(01 (1) over bar 2)(LiTaO3). This epitaxial relationship corresponds to the c axis of ZnO parallel to the piezoelectric r-plane LiTaO3, which results in the enhanced electromechanical coupling factor. The interfaces were very smooth and structurally semicoherent with a comparative regular array of misfit dislocations at the interface accommodating a lattice mismatch of 9.49% when the incident electron beam is parallel to the [0001](ZnO)parallel to[0 (1) over bar 11](LiTaO3) direction. A high efficiency of transfer of acoustic energy across the interface is expected for surface acoustic wave devices with such an interface. The dominant defects commonly observed in ZnO films were found to be the type-I-1 intrinsic stacking fault. The formation of stacking faults was shown to be growth kinetics on particular crystallographic planes during the initial stage of film growth. The effects of these defects and interfaces on electrical and optical properties for device applications are discussed. (C) 2000 American Institute of Physics. [S0021-8979(00)05121-5]. C1 Tohoku Univ, Inst Adv Mat Proc, Sendai, Miyagi 9808577, Japan. RP Lim, SH (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, 62-203, Berkeley, CA 94720 USA. RI Shindo, Daisuke/I-3865-2012 NR 32 TC 13 Z9 14 U1 0 U2 12 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD NOV 1 PY 2000 VL 88 IS 9 BP 5107 EP 5112 DI 10.1063/1.1313777 PG 6 WC Physics, Applied SC Physics GA 363BL UT WOS:000089813800026 ER PT J AU Girt, E Krishnan, KM Thomas, G Altounian, Z Dikeakos, M AF Girt, E Krishnan, KM Thomas, G Altounian, Z Dikeakos, M TI Approaching the theoretical coercivity of Nd2Fe14B: Microstructural evaluation and interparticle interactions SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID MAGNETIC-PROPERTIES AB The microstructure of melt-spun rapidly quenched NddeltaFe13.1B (2.05 less than or equal to delta less than or equal to 147.6) and NddeltaFe14B (delta=40.6,151.7) ribbons was tailored by appropriate annealing from strongly interacting to magnetically isolated single domain Nd2Fe14B grains embedded in a nonmagnetic matrix of alpha-Nd and gamma-Nd. This microstructure, as characterized by a variation in the magnetic interaction between Nd2Fe14B grains, was found to have a large impact on coercivity, mu(0)H(c), i.e., coercivity increases with an increase in the Nd concentration from 1.2 T in Nd2.05Fe13.1B to 2.75 T in Nd147.6Fe13.1B at 290 K. A detailed study of the microstructure of NddeltaFe13.1B (delta=38.1,148.7), carried out by conventional transmission electron microscopy, energy-filtered imaging, and energy dispersive x-ray microanalysis, showed that the majority of the Nd2Fe14B grains are completely isolated only in Nd147.6Fe13.1B. The Nd2Fe14B grains, in Nd147.6Fe13.1B, are found to be randomly oriented platelets with the c axis normal to the platelet and an average size of 100x40x25 nm. For these randomly oriented, noninteracting, single domain Nd2Fe14B grains, the coercivity was calculated using the Stoner-Wohlfarth model and including the shape anisotropy of the grains. The observed coercivity of Nd2Fe14B in Nd147.6Fe13.1B is similar to 83% of this theoretical value and is the largest so far reported for Nd2Fe14B. (C) 2000 American Institute of Physics. [S0021-8979(00)05621-8]. 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. McGill Univ, Dept Phys, Ctr Phys Mat, Montreal, PQ H3A 2T8, Canada. RP Krishnan, KM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Altounian, Zaven/A-2073-2008 NR 13 TC 5 Z9 5 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD NOV 1 PY 2000 VL 88 IS 9 BP 5311 EP 5314 DI 10.1063/1.1313782 PG 4 WC Physics, Applied SC Physics GA 363BL UT WOS:000089813800062 ER PT J AU Brown, JM Fritz, JN Hixson, RS AF Brown, JM Fritz, JN Hixson, RS TI Hugoniot data for iron SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID HIGH-PRESSURES; EARTHS CORE; TEMPERATURES; PHASE AB A definitive set of the Los Alamos Hugoniot data for iron in a pressure regime extending to 442 GPa is given. Earlier standards data, obtained using conventional explosive systems, were thoroughly reprocessed. All original film records were reread. On the basis of more recent experiment and theory, some data were culled because the experimental designs were found to be insufficiently conservative. The analysis was also modified to take into account preheating of the explosively driven flyer plates. Minor clerical errors in transcription of measurements were corrected. An improved algorithm for the flash-gap time correction was incorporated. Higher-pressure data were obtained using a conventional 13-pin target assembly on a two-stage light gas gun. Several polynomial representations of the data are given. A linear fit to the data (U-s=3.935+1.578 U-p, where the shock velocity U-s and the particle velocity U-p are in km/s) has a root-mean-square misfit of 62 m/s. The quadratic fit (U-s=3.691+1.788 U-p-0.038 U-p(2)) has a root-mean-square misfit of 39 m/s. (C) 2000 American Institute of Physics. [S0021-8979(00)01123-3]. C1 Univ Washington, Geophys Program, Seattle, WA 98195 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Brown, JM (reprint author), Univ Washington, Geophys Program, Seattle, WA 98195 USA. EM brown@geophys.washington.edu NR 22 TC 60 Z9 68 U1 2 U2 15 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 NOV 1 PY 2000 VL 88 IS 9 BP 5496 EP 5498 AR PII [S0021-8979(00)01123-3] DI 10.1063/1.1319320 PG 3 WC Physics, Applied SC Physics GA 363BL UT WOS:000089813800093 ER PT J AU Macey, PM Richard, CA Rector, DM Harper, RK Harper, RM AF Macey, PM Richard, CA Rector, DM Harper, RK Harper, RM TI State influences on ventral medullary surface and physiological responses to sodium cyanide challenges SO JOURNAL OF APPLIED PHYSIOLOGY LA English DT Article DE hypoxia; peripheral chemoreceptors; optical imaging; sleep; respiration ID ANESTHETIZED GOATS; LIGHT-SCATTERING; SLEEP; STIMULATION; CAT; HYPOXIA; MICRODIALYSIS; INJECTION; SIGNALS; CORTEX AB Intravenous sodium cyanide (NaCN) administration lowers ventral medullary surface (VMS) activity in anesthetized cats. Sleep states modify spontaneous and blood pressure-evoked VMS activity and may alter VMS responses to chemoreceptor input. We studied VMS activation during peripheral chemoreceptor stimulation by intravenous NaCN using optical procedures in six cats instrumented for recording sleep physiology during sham saline and control site trials. Images of scattered 660-nm light were collected at 50 frames/s with an optical device after 80-100 mug total bolus intravenous NaCN delivery during waking and sleep states. Cyanide elicited an initial ventilatory decline, followed by large inspiratory efforts and an increase in respiratory rate, except in rapid eye movement sleep, in which an initial breathing increase occurred. NaCN evoked a pronounced decrease in VMS activity in all states; control sites and sham injections showed little effect. The activity decline was faster in rapid eye movement sleep, and the activity nadir occurred later in waking. Sleep states alter the time course but not the extent of decline in VMS activity. C1 Univ Calif Los Angeles, Sch Med, Dept Neurobiol, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Sch Med, Brain Res Inst, Los Angeles, CA 90095 USA. Univ Calif Irvine, Irvine Med Ctr, Sleep Disorders Ctr, Dept Neurol, Orange, CA 92868 USA. Univ Calif Los Alamos Natl Lab, Biophys Grp, Los Alamos, NM 87545 USA. RP Harper, RM (reprint author), Univ Calif Los Angeles, Sch Med, Dept Neurobiol, 10833 Le Conte Ave, Los Angeles, CA 90095 USA. OI Macey, Paul/0000-0003-4093-7458 FU NHLBI NIH HHS [R01 HL-22418] NR 33 TC 3 Z9 3 U1 0 U2 0 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 8750-7587 J9 J APPL PHYSIOL JI J. Appl. Physiol. PD NOV PY 2000 VL 89 IS 5 BP 1919 EP 1927 PG 9 WC Physiology; Sport Sciences SC Physiology; Sport Sciences GA 369FH UT WOS:000165054900032 PM 11053344 ER PT J AU Kennel, SJ Foote, LJ Morris, M Vass, AA Griest, WH AF Kennel, SJ Foote, LJ Morris, M Vass, AA Griest, WH TI Mutation analyses of a series of TNT-related compounds using the CHO-hprt assay SO JOURNAL OF APPLIED TOXICOLOGY LA English DT Article DE TNT; CHO; mutagen; TNT metabolites ID HAMSTER OVARY CELLS; PHOSPHORIBOSYL TRANSFERASE LOCUS; HGPRT SYSTEM; IN-VITRO; QUANTITATIVE ASSAY; MAMMALIAN-CELLS; INDUCTION; METHOXYACETALDEHYDE AB Trinitrotoluene (TNT) and related compounds were tested for induction of mutation in the CHO-hprt mutation assay. The parent compound, TNT, was consistently found to be mutagenic at concentrations above 40 mug ml(-1), whether or not S9 activating enzymes were added. Five TNT metabolites gave statistically significant but small increases in mutation frequency over solvent controls: 4-amino-2,6-dinitrotoluene, 2,4',6,6'-tetranitro-2',4-azoxytoluene, 2,2',6,6'- tetranitro-4,4'-azoxytoluene, 2',4,6,6'-tetranitra-2,4'-azoxytoluene and triaminotoluene. Clear dose-response relationships could not be established for the mutagenic response of these compounds. They are considered as very weak mutagens in this mammalian test system. Five compounds did not produce statistically significant mutation frequencies at the levels tested: 2-amino-4,6-dinitrotoluene, 2,4-diamino-6-nitrotoluene, 1,3,5-trinitrobenzene, 2,6-diamino-4-nitrotoluene and 4,4',6,6'-tetranitro-2,2'-azoxytoluene. The results indicate that none of the TNT metabolites tested pose a significant mutational health risk, at least as judged by the CHO-hprt assay. Copyright (C) 2000 John Wiley & Sons, Ltd. C1 Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Iowa State Univ, Dept Stat, Ames, IA USA. RP Kennel, SJ (reprint author), Oak Ridge Natl Lab, Div Life Sci, POB 2008, Oak Ridge, TN 37831 USA. NR 27 TC 7 Z9 7 U1 1 U2 5 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0260-437X J9 J APPL TOXICOL JI J. Appl. Toxicol. PD NOV-DEC PY 2000 VL 20 IS 6 BP 441 EP 448 DI 10.1002/1099-1263(200011/12)20:6<441::AID-JAT711>3.0.CO;2-W PG 8 WC Toxicology SC Toxicology GA 386XL UT WOS:000166090100004 PM 11180265 ER PT J AU Davis, KJ Gamage, N Hagelberg, CR Kiemle, C Lenschow, DH Sullivan, PP AF Davis, KJ Gamage, N Hagelberg, CR Kiemle, C Lenschow, DH Sullivan, PP TI An objective method for deriving atmospheric structure from airborne lidar observations SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID BOUNDARY-LAYER; ENTRAINMENT; SYSTEM; OZONE AB Wavelet analysis is applied to airborne infrared lidar data to obtain an objective determination of boundaries in aerosol backscatter that are associated with boundary layer structure. This technique allows high-resolution spatial variability of planetary boundary layer height and other structures to be derived in complex, multilayered atmospheres. The technique is illustrated using data from four different lidar systems deployed on four different field campaigns. One case illustrates high-frequency retrieval of the top of a strongly convective boundary layer. A second case illustrates the retrieval of multiple layers in a complex, stably stratified region of the lower troposphere. The method is easily modified to allow for varying aerosol distributions and data quality. Two more difficult cases, data that contain a great deal of instrumental noise and a cloud-topped convective layer, are described briefly. The method is also adaptable to model analysis, as is shown via application to large eddy simulation data. C1 Univ Minnesota, Dept Soil Water & Climate, St Paul, MN 55108 USA. Univ Corp Atmospher Res, Boulder, CO USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. Deutsch Zentrum Luft & Raumfahrt, Lidar Grp, Oberpfaffenhofen, Germany. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. RP Davis, KJ (reprint author), Penn State Univ, Dept Meteorol, 512 Walker Bldg, University Pk, PA 16802 USA. RI Hagelberg, Carl/E-9554-2014; OI Hagelberg, Carl/0000-0002-2073-3127; LENSCHOW, DONALD/0000-0003-4353-0098 NR 35 TC 108 Z9 111 U1 0 U2 12 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD NOV PY 2000 VL 17 IS 11 BP 1455 EP 1468 DI 10.1175/1520-0426(2000)017<1455:AOMFDA>2.0.CO;2 PG 14 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 377LR UT WOS:000165515500002 ER PT J AU Hopfner, KP Karcher, A Shin, D Fairley, C Tainer, JA Carney, JP AF Hopfner, KP Karcher, A Shin, D Fairley, C Tainer, JA Carney, JP TI Mre11 and Rad50 from Pyrococcus furiosus: Cloning and biochemical characterization reveal an evolutionarily conserved multiprotein machine SO JOURNAL OF BACTERIOLOGY LA English DT Article ID STRAND BREAK REPAIR; ESCHERICHIA-COLI K-12; SACCHAROMYCES-CEREVISIAE; GENETIC-RECOMBINATION; PROTEIN COMPLEX; DNA PALINDROMES; MAINTENANCE; BINDING; YEAST; CELLS AB The processing of DNA double-strand breaks is a critical event in nucleic acid metabolism. This is evidenced by the severity of phenotypes associated with deficiencies in this process in multiple organisms. The core component involved in double-strand break repair in eukaryotic cells is the Mre11-Rad50 protein complex, which includes a third protein, p95, in humans and Xrs2 in yeasts. Homologues of Mre11 and Rad50 have been identified in all kingdoms of life, while the Nbs1 protein family is found only in eukaryotes. In eukaryotes the Mre11-Rad50 complex has nuclease activity that is modulated by the addition of ATP. We have isolated the Mre11 and Rad50 homologues from the thermophilic archaeon Pyrococcus furiosus and demonstrate that the two proteins exist in a large, heat-stable complex that possesses single-strand endonuclease activity and ATP-dependent double-strand-specific exonuclease activity. These findings verify the identification of the P. furiosus Rad50 and Mre11 homologues and demonstrate that functional homologues with similar biochemical properties exist in all kingdoms of life. C1 Univ Maryland, Sch Med, Radiat Oncol Res Lab, Baltimore, MD 21201 USA. Univ Maryland, Sch Med, Marlene & Stewart Greenebaum Canc Ctr, Baltimore, MD 21201 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Scripps Res Inst, Dept Mol Biol, La Jolla, CA 92037 USA. Scripps Res Inst, Skaggs Inst Chem Biol, La Jolla, CA 92037 USA. RP Carney, JP (reprint author), Univ Maryland, Sch Med, Radiat Oncol Res Lab, Bressler Res Bldg,6-015,655 W Baltimore St, Baltimore, MD 21201 USA. RI Hopfner, Karl-Peter/B-6864-2014 OI Hopfner, Karl-Peter/0000-0002-4528-8357 FU NIGMS NIH HHS [GM53918] NR 27 TC 84 Z9 89 U1 1 U2 2 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0021-9193 J9 J BACTERIOL JI J. Bacteriol. PD NOV PY 2000 VL 182 IS 21 BP 6036 EP 6041 DI 10.1128/JB.182.21.6036-6041.2000 PG 6 WC Microbiology SC Microbiology GA 364MQ UT WOS:000089896500013 PM 11029422 ER PT J AU DeRocher, A Hagen, CB Froehlich, JE Feagin, JE Parsons, M AF DeRocher, A Hagen, CB Froehlich, JE Feagin, JE Parsons, M TI Analysis of targeting sequences demonstrates that trafficking to the Toxoplasma gondii plastid branches off the secretory system SO JOURNAL OF CELL SCIENCE LA English DT Article DE Toxoplasma gondii; apicoplast; protein targeting; mitochondrion; chloroplast ID CHLOROPLAST TRANSIT PEPTIDES; ENDOPLASMIC-RETICULUM; APICOMPLEXAN PARASITES; DIATOM PLASTIDS; CLEAVAGE SITES; PROTEIN; MITOCHONDRIAL; GREEN; LOCALIZATION; TRANSPORT AB Apicomplexan parasites possess a plastid-like organelle called the apicoplast. Most proteins in the Toxoplasma gondii apicoplast are encoded in the nucleus and imported post-translationally. I: gondii apicoplast proteins often have a long N-terminal extension that directs the protein to the apicoplast. It can be modeled as a bipartite targeting sequence that contains a signal sequence and a plastid transit peptide. We identified two nuclearly encoded predicted plastid proteins and made fusions with green fluorescent protein to study protein domains required for apicoplast targeting. The N-terminal 42 amino acids of the apicoplast ribosomal protein S9 directs secretion of green fluorescent protein, indicating that targeting to the apicoplast proceeds through the secretory system. Large sections of the S9 predicted transit sequence can be deleted with no apparent impact on the ability to direct green fluorescent protein to the apicoplast. The predicted transit peptide domain of the S9 targeting sequence directs protein to the mitochondrion in vivo. The transit peptide can also direct import of green fluorescent protein into chloroplasts in vitro. These data substantiate the model that protein targeting to the apicoplast involves two distinct mechanisms: the first involving the secretory system and the second sharing features with typical chloroplast protein import. C1 Seattle Biomed Res Inst, Seattle, WA 98109 USA. Michigan State Univ, MSU DOE Plant Res Lab, E Lansing, MI 48824 USA. Univ Washington, Sch Publ Hlth & Community Med, Dept Pathobiol, Seattle, WA 98195 USA. RP Parsons, M (reprint author), Seattle Biomed Res Inst, 4 Nickerson St, Seattle, WA 98109 USA. FU NIAID NIH HHS [AI 42493, R03 AI042493-02, R03 AI042493-03, R03 AI042493] NR 38 TC 79 Z9 81 U1 0 U2 1 PU COMPANY OF BIOLOGISTS LTD PI CAMBRIDGE PA BIDDER BUILDING CAMBRIDGE COMMERCIAL PARK COWLEY RD, CAMBRIDGE CB4 4DL, CAMBS, ENGLAND SN 0021-9533 J9 J CELL SCI JI J. Cell Sci. PD NOV PY 2000 VL 113 IS 22 BP 3969 EP 3977 PG 9 WC Cell Biology SC Cell Biology GA 383FJ UT WOS:000165872200010 PM 11058084 ER PT J AU Zou, P McGivern, WS Sorkhabi, O Suits, AG North, SW AF Zou, P McGivern, WS Sorkhabi, O Suits, AG North, SW TI Quantum yields and energy partitioning in the ultraviolet photodissociation of 1,2 dibromo-tetrafluoroethane (Halon-2402) SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID TIME-OF-FLIGHT; MULTIPHOTON IONIZATION; GAS-PHASE; MOLECULAR-BEAMS; CROSS-SECTIONS; DISSOCIATION; KINETICS; DYNAMICS; RADICALS; OZONE AB The photodissociation of 1,2 dibromo-tetrafluoroethane (Halon-2402) has been investigated at 193 nm using photofragment translational spectroscopy with vacuum ultraviolet ionization and at 193, 233, and 266 nm using state-selected translational spectroscopy with resonance-enhanced multiphoton ionization. The product branching ratios, angular distributions, and translational energy distributions were measured at these wavelengths, providing insight into the ultraviolet photodissociation dynamics of CF2BrCF2Br. The total bromine atom quantum yields were found to be 1.9 +/-0.1 at both 193 and 233 nm and 1.4 +/-0.1 at 266 nm. The first C-Br bond dissociation energy was determined to be 69.3 kcal/mol from ab initio calculations. The second C-Br bond dissociation energy was determined to be 16 +/-2 kcal/mol by modeling of the bromine quantum yield. In addition, variational Rice-Ramsperger-Kassel-Marcus theory was used to calculate the secondary dissociation rates for a range of dissociation energies above threshold. These results suggest that CF2CF2Br photofragments with sufficient internal energies will undergo secondary dissociation prior to collisional stabilization under atmospheric conditions. Based on the measured translational energy distributions and product branching ratios, a model is proposed to describe the wavelength-dependent bromine quantum yield and the implications of these results to atmospheric chemistry are discussed. (C) 2000 American Institute of Physics. [S0021-9606(00)01941-3]. C1 Texas A&M Univ, Dept Chem, College Stn, TX 77842 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Zou, P (reprint author), Texas A&M Univ, Dept Chem, College Stn, TX 77842 USA. EM north@mail.chem.tamu.edu RI North, Simon/G-5054-2012 OI North, Simon/0000-0002-0795-796X NR 53 TC 6 Z9 6 U1 1 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD NOV 1 PY 2000 VL 113 IS 17 BP 7149 EP 7157 AR PII [S0021-9606(00)01941-3] DI 10.1063/1.1313545 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 368TD UT WOS:000090132900014 ER PT J AU Bacon, JA Pratt, ST AF Bacon, JA Pratt, ST TI Photoelectron spectroscopy of ammonia: Mode-dependent vibrational autoionization SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID TRIPLE-RESONANCE SPECTROSCOPY; HIGHER EXCITED-STATES; HIGH RYDBERG STATES; QUANTUM-DEFECT THEORY; MULTIPHOTON IONIZATION; FLUORESCENCE EXCITATION; POLYATOMIC-MOLECULES; HIGH-RESOLUTION; PHOTOIONIZATION; NO2 AB Photoelectron spectroscopy was used to study the mode dependence of vibrational autoionization in high-Rydberg states of NH3. Two-color, two-photon resonant, three-photon excitation via the C' (1)A(1)'(1300) intermediate state was used to populate selected autoionizing Rydberg states between the (1200) and (1300) ionization thresholds of the NH3+ (X) over tilde (2)A(2)" ground electronic state, and the ionic vibrational distributions were determined from the photoelectron spectra. Excitation of Rydberg states in which two different vibrational modes are excited allowed the direct comparison of the autoionization efficiencies for the two modes. Autoionization via the loss of one quantum of vibrational energy from the nontotally symmetric "umbrella" mode, nu (2), was found to be the dominant autoionization process. Vibrational branching fractions obtained from the ionic vibrational distributions indicate that, for the Rydberg states accessed via the C-' (1)A(1)'(1300) intermediate state, the nu (2) mode is approximately 25 times more efficient at promoting autoionization than the totally symmetric stretching mode, nu (1). (C) 2000 American Institute of Physics. [S0021-9606(00)01241-1]. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Bacon, JA (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 46 TC 11 Z9 11 U1 0 U2 8 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD NOV 1 PY 2000 VL 113 IS 17 BP 7188 EP 7196 DI 10.1063/1.1312286 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 368TD UT WOS:000090132900019 ER PT J AU Gray, SK Balint-Kurti, GG Schatz, GC Lin, JJ Liu, XH Harich, S Yang, XM AF Gray, SK Balint-Kurti, GG Schatz, GC Lin, JJ Liu, XH Harich, S Yang, XM TI Probing the effect of the H-2 rotational state in O(D-1)+H-2 -> OH+H: Theoretical dynamics including nonadiabatic effects and a crossed molecular beam study SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID POTENTIAL-ENERGY SURFACE; ABSOLUTE RATE CONSTANTS; REAGENT ROTATION; REACTIVE SCATTERING; QUANTUM DYNAMICS; EXCITED SURFACES; SECTIONS; O(D-1)+HD; HD; H+D-2->HD+D AB Theoretical estimates of reactive cross sections for O(D-1)+H-2(X,upsilon =0,j)--> OH(X)+H(S-2), with H-2 rotational quantum numbers j=0 and 1, are obtained for a range of collision energies, E-col. Crossed molecular beam measurements are also used to infer the ratio, r(1,0), of the j=1 and 0 cross sections at E-col=0.056 eV. The theory indicates that the 1 (1)A' potential surface is the most important one. However, the 2 (1)A' and 1 (1)A' surfaces can also contribute. Adiabatic dynamics on the 1 (1)A' surface, particularly at E-col above its 0.1 eV barrier to reaction plays a role. The 2 (1)A' surface, while not correlating with ground electronic state products, can still lead to products via nonadiabatic interactions with the 1 (1)A' surface. Many quantum dynamics and quasiclassical classical trajectory calculations are carried out. Accurate, ab initio based potential energy surfaces are employed. Quantum cross sections are based on helicity decoupled wave packet calculations for several values of total angular momentum. Nonadiabatic wave packet and trajectory surface hopping calculations, where appropriate, are carried out. An interesting, subtle picture emerges regarding the energy dependence of r(1,0). The theoretical results indicate, somewhat surprisingly, that, for E-col<0.1 eV,r(1,0) can be less than unity owing to the anisotropy of the ground state potential. Electronically excited states and nonadiabatic effects contribute to the overall cross sections for E-col>0.1 eV, but the full r(1,0) is only weakly sensitive to excited states. Our experimentally inferred r(1,0) at E-col=0.056 eV, 0.95 +/-0.02, is in quantitative agreement with our best calculation, which suggests that the effect of potential anisotropy is correctly described by theory. The relation between these results and previous experimental findings is discussed. (C) 2000 American Institute of Physics. [S0021-9606(00)02041-9]. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Univ Bristol, Sch Chem, Bristol B58 1TS, Avon, England. Northwestern Univ, Dept Chem, Evanston, IL 60208 USA. Acad Sinica, Inst Atom & Mol Sci, Taipei 10764, Taiwan. Natl Tsing Hua Univ, Dept Chem, Hsinchu, Taiwan. RP Gray, SK (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Yang, Xueming/C-8764-2013 NR 47 TC 89 Z9 89 U1 3 U2 17 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD NOV 1 PY 2000 VL 113 IS 17 BP 7330 EP 7344 DI 10.1063/1.1313785 PG 15 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 368TD UT WOS:000090132900033 ER PT J AU Hanson, DE AF Hanson, DE TI A mesoscale strength model for silica-filled polydimethylsiloxane based on atomistic forces obtained from molecular dynamics simulations SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID REINFORCEMENT; COMPOSITES AB We present a novel mesoscale model that describes the tensile stress of silica-filled polydimethylsiloxane (PDMS) under elongation. The model is based on atomistic simulations of a single chain of PDMS, interacting with itself and/or a hydroxylated silica surface. These simulations provide estimates of the microscopic forces required to stretch or uncoil a chain of PDMS, or detach it from a silica surface. For both stretching and detachment, we find that the internal potential energy is linear with the distance the chain end is moved, albeit with differing slopes. From these calculations and recent atomic force microscopy (AFM) experiments, we conclude that the forces are constant. We apply this analysis to the case of uncrosslinked, silica-filled PDMS systems and develop a mesoscale, inter-particle strength model. The strength model includes the atomistic forces determined from the simulations, a small entropic component, and a Gaussian probability distribution to describe the distribution of chain lengths of PDMS strands connecting two silica particles and the chain lengths in the free ends. We obtain an analytic stress/strain expression whose predictions agree with experiment. This model also suggests mechanisms to explain the phenomena of hysteresis and permanent set. (C) 2000 American Institute of Physics. [S0021-9606(00)52341-1]. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Hanson, DE (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 22 TC 14 Z9 14 U1 2 U2 6 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD NOV 1 PY 2000 VL 113 IS 17 BP 7656 EP 7662 AR PII [S0021-9606(00)52341-1] DI 10.1063/1.1313536 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 368TD UT WOS:000090132900072 ER PT J AU Wu, GS Schatz, GC Lendvay, G Fang, DC Harding, LB AF Wu, GS Schatz, GC Lendvay, G Fang, DC Harding, LB TI A new potential surface and quasiclassical trajectory study of H+H2O -> OH+H-2 (vol 113, pg 3150, 2000) SO JOURNAL OF CHEMICAL PHYSICS LA English DT Correction C1 Northwestern Univ, Dept Chem, Evanston, IL 60208 USA. Hungarian Acad Sci, Chem Res Ctr, Inst Chem, H-1525 Budapest, Hungary. Argonne Natl Lab, Theoret Chem Grp, Argonne, IL 60439 USA. RP Wu, GS (reprint author), Northwestern Univ, Dept Chem, 2145 Sheridan Rd, Evanston, IL 60208 USA. RI Lendvay, Gyorgy/B-5397-2016 OI Lendvay, Gyorgy/0000-0002-2150-0376 NR 1 TC 20 Z9 20 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD NOV 1 PY 2000 VL 113 IS 17 BP 7712 EP 7712 DI 10.1063/1.1311968 PG 1 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 368TD UT WOS:000090132900077 ER PT J AU Albright, JG Rard, JA Serna, S Summers, EE Yang, MC AF Albright, JG Rard, JA Serna, S Summers, EE Yang, MC TI Isopiestic determination of the osmotic and activity coefficients of ZnSO4(aq) at T=298.15 K, and the standard potential of the electrochemical cell ZnHgx(two phase)vertical bar ZnSO4(aq)vertical bar PbSO4(s)vertical bar PbHgx(two phase) SO JOURNAL OF CHEMICAL THERMODYNAMICS LA English DT Article DE isopiestic measurements; zinc sulfate; osmotic coefficient; activity coefficient; Pitzer's equation; standard potential ID MUTUAL DIFFUSION-COEFFICIENTS; LIQUID-MEMBRANE CELLS; THERMODYNAMIC PROPERTIES; 298.15 K; SULFATE ELECTRODE; 25-DEGREES-C; SOLUBILITY; SYSTEM; TEMPERATURE; WATER AB Isopiestic vapor-pressure measurements were made for ZnSO4(aq) at T = 298.15 K, both at Texas Christian University and at Lawrence Livermore National Laboratory, from molality m = 0.1004 mol . kg(-1) to the supersaturated m = 4.3092 mol . kg(-1), and included solubility determinations. These results were combined with critically assessed e.m.f. results from m = 6.7 . 10(-4) to m = 3.4413 mol . kg(-1) to yield recommended values of the osmotic coefficients, water activities, and mean activity coefficients of ZnSO4(aq), along with the thermodynamic solubility product and a CODATA compatible value for the Gibbs free energy of formation of goslarite: K-s{ZnSO4 . 7H(2)O(cr, orthorhombic)} = (0.01119 +/- 0.00033) and Delta (f)G(m)(o),(ZnSO4 . 7H(2)O, cr, orthorhombic, 298.15 K) = -(2562.32 +/- 0.57) kJ . mol(-1). An equation of the type used by Pitzer and Mayorga (J. Solution Chem. 1974, 3, 539-546) accurately represents the experimental osmotic coefficients and e.m.f.s provided it is modified by making the third virial coefficient ionic-strength dependent and by adding a fourth virial term. However, the mean activity coefficients of ZnSO4(aq) undergo a change from negative deviations from the Debye-Huckel limiting law below m similar to 0.01 mol . kg(-1) to positive deviations at higher molalities as described by Malatesta and Zamboni (J. Solution Chem. 1997, 26, 791-815), and our recommended values were adjusted for this effect. The standard potential of the reversible electrochemical cell: ZnHgx(two phase)\ZnSO4(aq)\PbSO4(cr)\PbHgx(two phase) was evaluated, and the resulting value was used for evaluating the standard potentials of the PbSO4(cr)\PbHgx(two phase) and Hg2SO4(cr)\Hg(1) electrodes. (C) 2000 Academic Press. C1 Univ Calif Lawrence Livermore Natl Lab, Geosci & Environm Technol Earth & Environm Sci Di, Livermore, CA 94550 USA. Texas Christian Univ, Dept Chem, Ft Worth, TX 76129 USA. RP Rard, JA (reprint author), Univ Calif Lawrence Livermore Natl Lab, Geosci & Environm Technol Earth & Environm Sci Di, Livermore, CA 94550 USA. NR 62 TC 25 Z9 25 U1 1 U2 10 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0021-9614 J9 J CHEM THERMODYN JI J. Chem. Thermodyn. PD NOV PY 2000 VL 32 IS 11 BP 1447 EP 1487 DI 10.1006/jcht.2000.0673 PG 41 WC Thermodynamics; Chemistry, Physical SC Thermodynamics; Chemistry GA 391JK UT WOS:000166352700002 ER PT J AU Wilson, DL Abner, SR Newman, TC Mansfield, LS Linz, JE AF Wilson, DL Abner, SR Newman, TC Mansfield, LS Linz, JE TI Identification of ciprofloxacin-resistant Campylobacter jejuni by use of a fluorogenic PCR assay SO JOURNAL OF CLINICAL MICROBIOLOGY LA English DT Article ID GYRASE GYRA GENE; DNA GYRASE; NUCLEOTIDE-SEQUENCE; QUINOLONE RESISTANCE; TOPOISOMERASE-IV; CLONING; MUTATIONS; PARC; SUBUNIT; COLI AB Fluoroquinolones are one class of antimicrobial agents commonly used to treat severe Campylobacter jejuni infection. C,jejuni strains resistant to high levels of the fluoroquinolone ciprofloxacin (MIC greater than or equal to 16 mug/ml) have been predominantly characterized with a C-->T transition in codon 86 of gyrA. The gyrA gene encodes one subunit of DNA gyrase, which is a primary target for fluoroquinolone antibiotics. This study establishes a rapid PCR-based TaqMan method for identifying ciprofloxacin-resistant C, jejuni strains that carry the C-->T transition in codon 86 of gyrA. The assay uses real-time detection, eliminating the need for gel electrophoresis. Optimization of the assay parameters using purified Campylobacter DNA resulted in the ability to detect femtogram levels of DNA. The method should be useful for monitoring the development of ciprofloxacin resistance in C. jejuni. Compiled nucleotide sequence data on the quinolone resistance-determining region of gyrA in Campylobacter indicate that sequence comparison of this region is a useful method for tentative identification of Campylobacter isolates at the species level. C1 Michigan State Univ, Natl Food Safety & Toxicol Ctr, E Lansing, MI 48824 USA. Michigan State Univ, Dept Food Sci & Human Nutr, E Lansing, MI 48824 USA. Michigan State Univ, Dept Microbiol, E Lansing, MI 48824 USA. Michigan State Univ, US DOE, Plant Res Lab, E Lansing, MI 48824 USA. RP Linz, JE (reprint author), Michigan State Univ, Natl Food Safety & Toxicol Ctr, E Lansing, MI 48824 USA. OI Mansfield, Linda S./0000-0002-7523-7577 NR 37 TC 57 Z9 61 U1 0 U2 2 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0095-1137 J9 J CLIN MICROBIOL JI J. Clin. Microbiol. PD NOV PY 2000 VL 38 IS 11 BP 3971 EP 3978 PG 8 WC Microbiology SC Microbiology GA 400VT UT WOS:000166892900011 PM 11060054 ER PT J AU Koning, J Rodrigue, G White, D AF Koning, J Rodrigue, G White, D TI Scalable preconditioned conjugate gradient inversion of vector finite element mass matrices SO JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS LA English DT Article DE Galerkin method; mass matrices; vector finite elements; conjugate gradient method; vector wave equation; Maxwell's equations AB Mass matrices arise in the numerical solution of time-dependent partial differential equations by the Galerkin method. Since these systems must be inverted at each time step, rapid inversion algorithms for these systems are important. When nodal finite elements are used as basis functions, it is known that the mass matrices can be consistently approximated by a diagonal matrix or solved by a scalable conjugate gradient method. This may not be the case for other basis functions. In this paper, we show that the preconditioned conjugate gradient method is scalable when used to invert mass matrices that arise from vector finite element basis functions. These basis functions are particularly important for solving Maxwell's equations on unstructured grids by the Galerkin method. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Davis, Dept Appl Sci, Livermore, CA 94550 USA. Univ Calif Lawrence Livermore Natl Lab, Inst Sci Comp Res, Livermore, CA 94550 USA. Univ Calif Lawrence Livermore Natl Lab, Ctr Adv Sci Comp, Livermore, CA 94550 USA. RP Rodrigue, G (reprint author), Univ Calif Davis, Dept Appl Sci, L-561,POB 808 L-794, Livermore, CA 94550 USA. NR 20 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0427 J9 J COMPUT APPL MATH JI J. Comput. Appl. Math. PD NOV 1 PY 2000 VL 123 IS 1-2 SI SI BP 307 EP 321 DI 10.1016/S0377-0427(00)00407-6 PG 15 WC Mathematics, Applied SC Mathematics GA 371VJ UT WOS:000165199700016 ER PT J AU Dongarra, JJ Eijkhout, V AF Dongarra, JJ Eijkhout, V TI Numerical linear algebra algorithms and software SO JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS LA English DT Article ID NONSEPARABLE ELLIPTIC-EQUATIONS; ITERATIVE SOLUTION; SYSTEMS; MATRICES; SUBPROGRAMS; GRAPHS; SET AB The increasing availability of advanced-architecture computers has a significant effect on all spheres of scientific computation, including algorithm research and software development in numerical linear algebra. Linear algebra - in particular, the solution of linear systems of equations - lies at the heart of most calculations in scientific computing. This paper discusses some of the recent developments in linear algebra designed to exploit these advanced-architecture computers. We discuss two broad classes of algorithms: those for dense, and those for sparse matrices. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Tennessee, Dept Comp Sci, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Math Sci Sect, Oak Ridge, TN 37831 USA. RP Dongarra, JJ (reprint author), Univ Tennessee, Dept Comp Sci, 107 Ayres Hall, Knoxville, TN 37996 USA. RI Dongarra, Jack/E-3987-2014 NR 64 TC 11 Z9 11 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0427 J9 J COMPUT APPL MATH JI J. Comput. Appl. Math. PD NOV 1 PY 2000 VL 123 IS 1-2 SI SI BP 489 EP 514 DI 10.1016/S0377-0427(00)00400-3 PG 26 WC Mathematics, Applied SC Mathematics GA 371VJ UT WOS:000165199700024 ER PT J AU Gnanapragasam, EK Yu, C Whelan, G Mills, WB McDonald, JP Lew, CS Hung, CY Hoffmeyer, D AF Gnanapragasam, EK Yu, C Whelan, G Mills, WB McDonald, JP Lew, CS Hung, CY Hoffmeyer, D TI Comparison of multimedia model predictions for a contaminant plume migration scenario SO JOURNAL OF CONTAMINANT HYDROLOGY LA English DT Article DE contaminant transport; groundwater; saturated zone; dispersion; retardation; progeny transport; model comparison ID RISK ASSESSMENT MODELS; BENCHMARKING ANALYSIS; MMSOILS; RESRAD; MEPAS AB Predictions of four risk assessment models - RESRAD, PRESTO, MMSOILS, and MEPAS for a test scenario involving the migration of a single, rapidly transforming radionuclide, Sr-90, and a persistent, long radionuclide chain, U-234 and its progeny, in groundwater are compared. All four models make comparable predictions for the plume centerline concentrations of the primary contaminants in the aquifer for a distance of up to about 300 m from the source. MEPAS, MMSOILS, and RESRAD make similar predictions for the transverse concentration profiles in the aquifer. The four models make considerably different predictions for the temporal concentration profiles of the progeny in the aquifer. The profiles differ in shape, magnitude of the peak, and in width. The differences are a result of the simplifying assumptions underlying each of the models. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Environm Assessment Div, Argonne, IL 60439 USA. Pacific NW Natl Lab, Environm Technol Div, Richland, WA 99352 USA. Tetra Tech Inc, Lafayette, CA 94549 USA. US EPA, Off Radiat & Indoor Air, Washington, DC 20005 USA. RP Gnanapragasam, EK (reprint author), Argonne Natl Lab, Environm Assessment Div, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 14 TC 7 Z9 8 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7722 J9 J CONTAM HYDROL JI J. Contam. Hydrol. PD NOV PY 2000 VL 46 IS 1-2 BP 17 EP 38 DI 10.1016/S0169-7722(00)00128-5 PG 22 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA 374NA UT WOS:000165350200002 ER PT J AU Birdsell, KH Wolfsberg, AV Hollis, D Cherry, TA Bower, KM AF Birdsell, KH Wolfsberg, AV Hollis, D Cherry, TA Bower, KM TI Groundwater flow and radionuclide transport calculations for a performance assessment of a low-level waste site SO JOURNAL OF CONTAMINANT HYDROLOGY LA English DT Article DE performance assessment; hydrology; radioactive waste; unsaturated zone ID POROUS-MEDIA; WATER; FIELD AB Predictions of subsurface radionuclide transport are used to support the groundwater pathway analysis for the performance assessment of the low-level, solid radioactive waste site at Los Alamos National Laboratory. Detailed process-based models rather than higher-level performance-assessment models are used to perform the transport calculations. The deterministic analyses predict the fate of the waste from its sour ce. through the vadose zone, into the saturated zone and, finally, the potential dose to humans at the accessible environment. The calculations are run with the finite-element code FEHM, which simulates fluid now, heat transport, and reactive, contaminant transport through porous and Fractured media. The modeling approach for this study couples realistic source-term models with an unsaturated-zone flow and transport model, which is then linked to the saturated-zone flow and transport model. The three-dimensional unsaturated-zone flow and transport model describes the complex hydrology associated with the mesa-top and volcanic geology of the site. The continued mi,oration of nuclides into the main;aquifer is calculated using a three-dimensional, steady-flow, saturated zone model that maintains the spatial and temporal distribution of nuclide flux from the vadose zone. Preliminary results for the aquifer-related dose assessments show that doses are well below relevant performance objectives for low-level waste sites. A general screening technique that compares the nuclide's half-life to its unsaturated-zone travel time is described. This technique helps to decrease the number of transport calculations required at a site. In this case, over half the nuclides were eliminated from further consideration through this screening. (C) 2000 Published by Elsevier Science B.V. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Eastern Illinois Univ, Charleston, IL 61920 USA. RP Birdsell, KH (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 39 TC 17 Z9 17 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7722 J9 J CONTAM HYDROL JI J. Contam. Hydrol. PD NOV PY 2000 VL 46 IS 1-2 BP 99 EP 129 DI 10.1016/S0169-7722(00)00129-7 PG 31 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA 374NA UT WOS:000165350200006 ER PT J AU Rodriguez, MA Yang, P Kotula, P Dimos, D AF Rodriguez, MA Yang, P Kotula, P Dimos, D TI Microstructure and phase development of buried resistors in low temperature Co-fired ceramic SO JOURNAL OF ELECTROCERAMICS LA English DT Article DE microstructure; buried resistor; LTCC; XRD; SEM ID FILM CERMET RESISTORS AB Embedded resistor circuits have been generated with the use of a Micropen system, Ag conductor paste (DuPont 6142D), a new experimental resistor ink from DuPont (E84005-140), and Low Temperature Co-fired Ceramic (LTCC) green tape (DuPont A951). Sample circuits were processed under varying peak temperature ranges (835 degreesC-875 degreesC) and peak soak times (10 min-720 min). Resistors were characterized by SEM, TEM, EDS, and high-temperature XRD. Results indicate that devitrification of resistor glass phase to Celcian, Hexacelcian, and a Zinc-silicate phase occurred in the firing ranges used (835-875 degreesC) but kinetics of divitrification vary substantially over this temperature range. The resistor material appears structurally and chemically compatible with the LTCC. RuO2 grains do not significantly react with the devitrifying matrix material during processing. RuO2 grains coarsen significantly with extended time and temperature and the electrical properties appear to be strongly affected by the change in RuO2 grain size. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Rodriguez, MA (reprint author), Sandia Natl Labs, POB 5800,MS 1405, Albuquerque, NM 87185 USA. RI Kotula, Paul/A-7657-2011 OI Kotula, Paul/0000-0002-7521-2759 NR 9 TC 26 Z9 27 U1 0 U2 5 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 1385-3449 J9 J ELECTROCERAM JI J. Electroceram. PD NOV PY 2000 VL 5 IS 3 BP 217 EP 223 DI 10.1023/A:1026575428178 PG 7 WC Materials Science, Ceramics SC Materials Science GA 379JG UT WOS:000165638500004 ER PT J AU Ng, CY AF Ng, CY TI High-resolution pulsed-field ionization photoelectron-photoion coincidence spectroscopy: Determination of accurate bond dissociation energies for neutrals and cations SO JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA LA English DT Article ID MULTIBUNCH SYNCHROTRON-RADIATION; THRESHOLD; MOLECULES; RANGE; BANDS; AFFINITIES; V(+)=0-38); SPECTRUM; RADICALS; METHYL AB We have established a high-resolution vacuum ultraviolet (VUV) photoionization-photoelectron facility at the chemical dynamics beamline of the advanced light source. This facility is equipped with a 6.65-m monochromator, which has demonstrated a resolving power of approximate to 100 000 in the range of 6-30 eV. This resolving power is close to that achieved in common VUV lasers. Taking advantage of this high-resolution capability, we have developed novel synchrotron based pulsed-field ionization-photoelectron (PFI-PE) schemes, attaining resolutions of 1-5 cm(-1) (FWHM), which are also similar to that attained in laser-based PFI-PE studies. Most recently, we have introduced a generally applicable PFI-PE-photoion coincidence (PFI-PEPICO) method, making possible the internal state selection for cations to a resolution of 4-5 cm(-1) (FWHM) limited only by the PFI-PE measurement. The PFI-PEPICO study of the reaction O-2 + h nu -->O+ (4S)+O((3)p)+e(-) demonstrates that the dissociation dynamics of diatomic cations can be examined in specific rotational levels using this method. This study also supports that the dissociation threshold for O+(S-4)+O(P-3) lies at O-2(+) (b4 Sigma (-)(g), upsilon (+) = 4, N+ = 9) In the PFI-PE-PICO study of CH4(C2H2), we show that the 0 K dissociative photoionization threshold for CH3+ (C2H+) from CH4 (C2H2) can be determined unambiguously by the disappearance energy of the CH4+ (C2H2+) parent ion to an accuracy of +/-0.001 eV. These measurements, when combined with accurate ionization energies fort CH3, CH4 and C2H2 obtained by PFI-PE measurements, have allowed the determination of highly accurate 0 K bond dissociation energies for H-CH3, H-CH3+, and H-C2H+. The PFI-PEPICO study of 2-C3H7X (X = Cl, Br and I) has yielded more accurate values for the heat of formation of C3H7+ and the proton affinity of C3H6. (C) 2000 Elsevier Science BN. All rights reserved. C1 US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP Ng, CY (reprint author), US DOE, Ames Lab, Ames, IA 50011 USA. NR 44 TC 8 Z9 8 U1 1 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0368-2048 J9 J ELECTRON SPECTROSC JI J. Electron Spectrosc. Relat. Phenom. PD NOV PY 2000 VL 112 IS 1-3 SI SI BP 31 EP 46 DI 10.1016/S0368-2048(00)00201-2 PG 16 WC Spectroscopy SC Spectroscopy GA 383DB UT WOS:000165866900004 ER PT J AU Wang, RH Zubia, D O'Neil, T Emin, D Aselage, T Zhang, W Hersee, SD AF Wang, RH Zubia, D O'Neil, T Emin, D Aselage, T Zhang, W Hersee, SD TI Chemical vapor deposition of B12As2 thin films on 6H-SiC SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article DE B12As2; thin films; CVD; 6H-SiC; substrates ID BORON-RICH SOLIDS AB Icosahedral boron arsenide (B12As2) thin films were deposited on 6H-SiC substrates by chemical vapor deposition using B2H6 and AsH3 sources. X-ray diffraction analysis of the thin films showed them to have the rhombohedral crystal structure and lattice parameters of B12As2. Transmission electron microscopy showed that the films were polycrystalline with oriented crystal grains. The preferential orientation of the film with respect to the SiC substrate was determined to be: [0001]B12As2//[0001](6H-SiC) and [10(1) over bar0](6H-SiC) to within 3 degrees. Electron diffraction also revealed the extremely small lattice mismatch (<0.5%) between the B12As2 basal-plane lattice parameter and twice the SiC basal-plane lattice parameter. C1 Univ New Mexico, Ctr High Technol Mat, Albuquerque, NM 87131 USA. Univ New Mexico, Dept Elect & Comp Engn, Albuquerque, NM 87131 USA. Univ New Mexico, Dept Phys & Astron, Albuquerque, NM 87131 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Wang, RH (reprint author), Univ New Mexico, Ctr High Technol Mat, Albuquerque, NM 87131 USA. NR 8 TC 14 Z9 14 U1 0 U2 5 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086 USA SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD NOV PY 2000 VL 29 IS 11 BP 1304 EP 1306 DI 10.1007/s11664-000-0129-x PG 3 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA 370AC UT WOS:000165099100002 ER PT J AU Handy, EM Rao, MV Holland, OW Chi, PH Jones, KA Derenge, MA Vispute, RD Venkatesan, T AF Handy, EM Rao, MV Holland, OW Chi, PH Jones, KA Derenge, MA Vispute, RD Venkatesan, T TI Al, B, and Ga ion-implantation doping of SiC SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article DE SiC; ion implantation; (Al,B,Ga implants); AlN encapsulant ID SILICON-CARBIDE; ALUMINUM IMPLANTATION; NITROGEN; BORON; ACTIVATION; PHOSPHORUS; PROFILES; DAMAGE; LAYERS; LASER AB A series of single energy Al, B, and Ga ion implants were performed in the energy range 50 keV to 4 MeV into 6H-SiC to characterize the implant depth profiles using secondary ion mass spectrometry (SIMS). From the implant depth profiles empirical formulae were developed to model the range statistics as functions of ion energy. Multiple energy implants were performed into 6H- and 4H-SiC and annealed with both AlN and graphite encapsulants to determine the ability of the encapsulants to protect the implants from out-diffusion and redistribution. Al and Ga were thermally stable, but B out-diffused even with AlN or graphite encapsulation. Electrical activation was determined by Hall and capacitance-voltage measurements. An acceptor substitutional concentration of 7 x 10(16) cm(-3) was achieved for 1 x 10(17) cm(3) Al implantation. C1 George Mason Univ, Dept Elect & Comp Engn, Fairfax, VA 22030 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. USA, Res Lab, SEDD, Adelphi, MD 20783 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. RP Handy, EM (reprint author), George Mason Univ, Dept Elect & Comp Engn, Fairfax, VA 22030 USA. RI Venkatesan, Thirumalai/E-1667-2013 NR 34 TC 18 Z9 18 U1 0 U2 14 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086 USA SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD NOV PY 2000 VL 29 IS 11 BP 1340 EP 1345 DI 10.1007/s11664-000-0135-z PG 6 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA 370AC UT WOS:000165099100008 ER PT J AU McCarthy, JF Howard, KM McKay, LD AF McCarthy, JF Howard, KM McKay, LD TI Effect of pH on sorption and transport of fluorobenzoic acid ground water tracers SO JOURNAL OF ENVIRONMENTAL QUALITY LA English DT Article ID ORGANIC-MATTER; HETEROGENEOUS AQUIFER; NONREACTIVE TRACERS; SOIL; ADSORPTION; SURFACE; CHROMATOGRAPHY; DISPERSION; MECHANISMS; CHEMICALS AB Sorption and transport behavior of fluorobenzoic acid (FBA) tracers were evaluated as ground water tracers in a highly weathered and fractured clay-rich saprolite under both acidic and neutral conditions in laboratory batch tests and column transport studies. The FBAs are a group of 14 organic acids with pK(a) from 2.71 to 3.83, and may thus be potentially retarded in weathered, acidic soils. The degree of sorption was directly related to the pK(a) of the isomer and the pH of the solution. A technique for determining the intrinsic partitioning coefficient (K-d) of an non-ionized species was derived to predict the equilibrium sorption of a family of compounds over a range of pH and pK(a),. For the diflourobenzoic acids used in this study, gd was 2.50 L/kg. The intact column transport experiments confirmed that at neutral pH, none of the FBA isomers were retarded relative to a nonreactive tracer (Br-). Under acidic conditions (pH = 5,2), significant retardation was observed for isomers with higher pK(a). Because the use of FBA tracers could be limited by regulatory concerns about potential toxic effects in surface water receiving discharge from ground water containing FBA, aquatic toxicity was assessed using a Ceriodaphnia 96-h acute toxicity test. The LD50 (the concentration resulting in mortality of greater than or equal to 50% of the test organisms) for the four FBA. isomers tested was above 100 mg/L. The results of these equilibrium isotherm and column transport experiments demonstrate that FBAs can be ver useful as nonreactive ground water tracers in these materials as long as the pH is approximately 2 pH units above the pK(a) (i.e., >99% ionized). C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Geol Sci, Knoxville, TN 37996 USA. Theta Technol Inc, Oak Ridge, TN 37830 USA. RP McCarthy, JF (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008,Bethel Valley Rd, Oak Ridge, TN 37831 USA. NR 40 TC 24 Z9 24 U1 1 U2 16 PU AMER SOC AGRONOMY PI MADISON PA 677 S SEGOE RD, MADISON, WI 53711 USA SN 0047-2425 J9 J ENVIRON QUAL JI J. Environ. Qual. PD NOV-DEC PY 2000 VL 29 IS 6 BP 1806 EP 1813 PG 8 WC Environmental Sciences SC Environmental Sciences & Ecology GA 374VC UT WOS:000165364200010 ER PT J AU Brown, RS Power, G Beltaos, S Beddow, TA AF Brown, RS Power, G Beltaos, S Beddow, TA TI Effects of hanging ice dams on winter movements and swimming activity of fish SO JOURNAL OF FISH BIOLOGY LA English DT Article DE frazil ice; winter; common carp; brown trout; habitat exclusion; EMG ID TROUT SALMO-TRUTTA; CUTTHROAT TROUT; ONCORHYNCHUS-CLARKI; HABITAT USE; RAM-RIVER; ALBERTA; FALL; TELEMETRY AB Formation of a hanging dam, a large, thick sub-surface accumulation of frazil ice that blocked river flow, altered physical environmental conditions dramatically and common carp Cyprinus carpio and brown trout Salmo trutta evacuated the pool in which the dam developed. A mean of 80.1% of the pool volume was filled with frazil ice. Mean and bottom water velocities in the pool increased from 6 to 27 cm s(-1) and from 4 to 21 cm s(-1), respectively, when the hanging dam formed, and water depth decreased from a mean of 2.25 to 0.45 m. Activity levels of fish leaving the pool varied. Two carp had higher swimming activities when in the overwintering pool, compared to the period when they were out of it, and a third showed opposite results. (C) 2000 The Fisheries Society of the British Isles. C1 Univ Waterloo, Dept Biol, Waterloo, ON N2L 3G1, Canada. Environm Canada, Canada Ctr Inland Waters, Natl Water Res Inst, Burlington, ON L7R 4A6, Canada. RP Brown, RS (reprint author), Pacific NW Natl Lab, Ecol Grp, MSIN K6-85,902 Battelle Blvd,POB 999, Richland, WA 99352 USA. OI Beltaos, Spyros/0000-0002-2247-8588 NR 27 TC 30 Z9 30 U1 0 U2 4 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-1112 J9 J FISH BIOL JI J. Fish Biol. PD NOV PY 2000 VL 57 IS 5 BP 1150 EP 1159 DI 10.1006/jfbi.2000.1378 PG 10 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 377BA UT WOS:000165491000005 ER PT J AU Randich, E Fickies, TE Tulleners, FA Andresen, BD Grant, PM AF Randich, E Fickies, TE Tulleners, FA Andresen, BD Grant, PM TI Restoration tactics for seriously corroded Cu and Cu-alloy firearms evidence SO JOURNAL OF FORENSIC SCIENCES LA English DT Article DE forensic science; evidence cleaning techniques; metal restoration; solvent treatments; firearms examination AB A cleaning procedure for seriously weathered or corroded bullets and cartridge casings was developed and implemented for evidence specimens from a multiple homicide. The restoration protocol entailed successive treatments with increasingly aggressive chemical solvents and cleaning solutions while monitoring the progress of the method by optical microscopy. Treatment of worst-case, Cu-alloy jacketed bullets and casings resulted in reconditioned specimens that subsequently underwent successful firearms examinations. C1 Univ Calif Lawrence Livermore Natl Lab, Forens Sci Ctr, Livermore, CA 94550 USA. Calif Dept Justice, Bur Forens Sci, Sacramento, CA USA. Calif Dept Justice, Calif Criminalist Inst, Sacramento, CA USA. RP Grant, PM (reprint author), Univ Calif Lawrence Livermore Natl Lab, Forens Sci Ctr, L-178, Livermore, CA 94550 USA. NR 4 TC 1 Z9 1 U1 0 U2 2 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 USA SN 0022-1198 J9 J FORENSIC SCI JI J. Forensic Sci. PD NOV PY 2000 VL 45 IS 6 BP 1316 EP 1319 PG 4 WC Medicine, Legal SC Legal Medicine GA 374WY UT WOS:000165368400025 PM 11110190 ER PT J AU Loots, E Isacoff, EY AF Loots, E Isacoff, EY TI Molecular coupling of S4 to a K+ channel's slow inactivation gate SO JOURNAL OF GENERAL PHYSIOLOGY LA English DT Article DE Shaker; rearrangement; voltage; gating; fluorescence ID C-TYPE INACTIVATION; SHAKER POTASSIUM CHANNELS; SELECTIVITY FILTER; ION INTERACTIONS; XENOPUS-OOCYTES; CHARGE MOVEMENT; SODIUM-CHANNELS; VOLTAGE SENSOR; PORE; MODULATION AB The mechanism by which physiological signals regulate the conformation of molecular gates that open and close ion channels is poorly understood. Voltage clamp fluorometry was used to ask how the voltage sensing S4 transmembrane domain is coupled to the slow inactivation gate in the pore domain of the Shaker K+ channel. Fluorophores attached at several sites in S4 indicate that the voltage-sensing rearrangements are followed by an additional inactivation motion. Fluorophores attached at the perimeter of the pore domain indicate that the inactivation rearrangement projects from the selectivity filter out to the interface with the voltage-sensing domain. Some of the pore domain sites also sense activation, and this appears to be due to a direct interaction with S4 based on the finding that S4 comes into close enough proximity to the pore domain for a pore mutation to alter the nanoenvironment of an S4-attached fluorophore. We propose that activation produces an S4-pore domain interaction that disrupts a bond between the S4 contact site on the pore domain and the outer end of S6. Our results indicate that this bond holds the slow inactivation gate open and, therefore, we propose that this S4-induced bond disruption triggers inactivation. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Dept Mol & Cell Biol, Berkeley, CA 94720 USA. RP Isacoff, EY (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Dept Mol & Cell Biol, 271 Life Sci Addit,MC 3200, Berkeley, CA 94720 USA. FU NINDS NIH HHS [NS35549, R01 NS035549] NR 68 TC 80 Z9 81 U1 0 U2 1 PU ROCKEFELLER UNIV PRESS PI NEW YORK PA 1114 FIRST AVE, 4TH FL, NEW YORK, NY 10021 USA SN 0022-1295 J9 J GEN PHYSIOL JI J. Gen. Physiol. PD NOV PY 2000 VL 116 IS 5 BP 623 EP 635 DI 10.1085/jgp.116.5.623 PG 13 WC Physiology SC Physiology GA 372LA UT WOS:000165234100003 PM 11055991 ER PT J AU Haggerty, DK Roelof, EC Smith, CW Ness, NF Tokar, RL Skoug, RM AF Haggerty, DK Roelof, EC Smith, CW Ness, NF Tokar, RL Skoug, RM TI Interplanetary magnetic field connection to the L1 Lagrangian orbit during upstream energetic ion events SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID EARTHS BOW SHOCK; ADVANCED-COMPOSITION-EXPLORER; ALPHA-MONITOR; FAR UPSTREAM; SOLAR-WIND; PROTONS; SPACECRAFT; PARTICLES; ISEE-3; ACE AB Energetic ions (>15 keV) moving upstream from the Earth's bow shock frequently appear at the sunward Lagrangian point (L1) similar to1.5 x 10(6) km upstream from Earth. The most common orientation of the interplanetary magnetic field (IMF) at L1 during these upstream events is near-radial from the Sun (the nominal direction for connection to the magnetosphere). However, strong unidirectional beams of ions streaming away from Earth, consistent with good magnetic connection to the bow shock, are observed even when the IMF is transverse to the radial direction. This study includes for the first time observations of upstream events from as many as four upstream spacecraft. Included in this report are energetic ion and magnetic field measurements from (1) ACE/Electron, Proton, and Alpha Monitor (EPAM) and ACE/Magnetometer Instrument (MAG); (2) Wind/Three-Dimensional Plasma Analyzer (3DP) and Wind/Magnetic Fields Investigation (MFI); (3) IMP 8/Energetic Particle Experiment (EPE) and IMP 8/MAG; and (4) Geotail/Energetic Particle and Ion Composition (EPIC) and Geotail/MAG. In addition, the ACE/Solar Wind Electron, Proton, and Alpha Monitor (SWEPAM) instrument identifies IMF connection between the L1 point and the Earth's bow shock by the presence of low-energy (272-372 eV) bidirectional electron flux. Instruments on the IMP 8 and Geotail spacecraft simultaneously measure the energetic ion intensity and IMF configuration close to the Earth's bow shock during times of particle enhancements observed at L1. Analysis of ACE, Wind, IMP 8, and Geotail observations from February through November 1998 shows that >40% of upstream events are observed during times of nonradial (>30 degrees from the GSE X axis) IMF orientation. A second and independent study of ACE/EPAM observations of over 500 upstream energetic ion events from launch through November 1998 confirms this result. We find similar distributions of radial and nonradial IMF orientations both close to the bow shock and at L1. This implies that the IMF configurations during upstream events are large-scale spatial structures with radii of curvature of the order of the Earth-L1 distance, i.e., 0.01 AU. These spatial structures are being convected through the L1 point into the Earth's foreshock. C1 Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Haggerty, DK (reprint author), Johns Hopkins Univ, Appl Phys Lab, Room 4-202,11100 Johns Hopkins Rd, Laurel, MD 20723 USA. NR 27 TC 14 Z9 14 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD NOV 1 PY 2000 VL 105 IS A11 BP 25123 EP 25131 DI 10.1029/1999JA000346 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 369YX UT WOS:000165096300018 ER PT J AU Russell, CT Wang, YL Raeder, J Tokar, RL Smith, CW Ogilvie, KW Lazarus, AJ Lepping, RP Szabo, A Kawano, H Mukai, T Savin, S Yermolaev, YI Zhou, XY Tsurutani, BT AF Russell, CT Wang, YL Raeder, J Tokar, RL Smith, CW Ogilvie, KW Lazarus, AJ Lepping, RP Szabo, A Kawano, H Mukai, T Savin, S Yermolaev, YI Zhou, XY Tsurutani, BT TI The interplanetary shock of September 24, 1998: Arrival at Earth SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID IONOSPHERIC MASS EJECTION; MAGNETIC-FIELD; SPACECRAFT; MAGNETOSPHERE; SATELLITE; WAVES AB At close to 2345 UT on September 24, 1998, the magnetosphere was suddenly compressed by the passage of an interplanetary shock. In order to properly interpret the magnetospheric events triggered by the arrival of this shock, we calculate the orientation of the shock, its velocity, and its estimated time of arrival at the nose of the magnetosphere. Our best fit shock normal has an orientation of (-0.981 -0.157 -0.112) in solar ecliptic coordinates, a speed of 769 km/s, and an arrival time of 2344:19 at the magnetopause at 10 R-E. Since measurements of the solar wind and interplanetary magnetic field are available from multiple spacecraft, we can compare several different techniques of shock-normal determination. Of the single spacecraft techniques the magnetic coplanarity solution is most accurate and the mixed mode solution is of lesser accuracy. Uncertainty in the timing and location of the IMP 8 spacecraft limits the accuracy of solutions using the time of arrival at the position of IMP 8. C1 Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. MIT, Space Res Ctr, Cambridge, MA 02139 USA. Kyushu Univ 33, Dept Earth & Planetary Sci, Higashi Ku, Fukuoka 8128581, Japan. Inst Space & Astronaut Sci, Sagamihara, Kanagawa 229, Japan. Russian Acad Sci, Space Res Inst, Moscow 117810, Russia. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Chinese Acad Sci, Inst Geophys, Beijing, Peoples R China. RP Russell, CT (reprint author), Univ Calif Los Angeles, Inst Geophys & Planetary Phys, 3845 Slichter Hall,405 Hilgard Ave, Los Angeles, CA 90095 USA. NR 26 TC 37 Z9 38 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD NOV 1 PY 2000 VL 105 IS A11 BP 25143 EP 25154 DI 10.1029/2000JA900070 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 369YX UT WOS:000165096300020 ER PT J AU Greiner, M Faulkner, RJ Van, VT Tufo, HM Fischer, PF AF Greiner, M Faulkner, RJ Van, VT Tufo, HM Fischer, PF TI Simulations of three-dimensional flow and augmented heat transfer in a symmetrically grooved channel SO JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME LA English DT Article DE augmentation; computational; forced convection; heat transfer; unsteady ID PRESSURE-DROP; DESTABILIZATION; ENHANCEMENT; TRANSITION AB Navier-Stokes simulations of three-dimensional flow and augmented convection in a channel with symmetric, transverse grooves on two opposite walls were performed for 180 less than or equal to Re less than or equal to 1600 using the spectral element technique. A series of flow transitions was observed as the Reynolds number was increased from steady two-dimensional flow, to traveling two and three-dimensional wave structures, and finally to three-dimensional mixing. Three-dimensional simulations exhibited good agreement with local and spatially averaged Nusselt number and friction factor measurements over the range 800 less than or equal to Re less than or equal to 1600. C1 Univ Nevada, Dept Mech Engn, Reno, NV 89557 USA. Univ Chicago, Dept Comp Sci, Chicago, IL 60637 USA. Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. RP Greiner, M (reprint author), Univ Nevada, Dept Mech Engn, Reno, NV 89557 USA. NR 19 TC 7 Z9 7 U1 0 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0022-1481 J9 J HEAT TRANS-T ASME JI J. Heat Transf.-Trans. ASME PD NOV PY 2000 VL 122 IS 4 BP 653 EP 660 DI 10.1115/1.1318207 PG 8 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 430PT UT WOS:000168583900002 ER PT J AU Ramanaiah, KCV Stevens, ED Trudell, ML Pagoria, PF AF Ramanaiah, KCV Stevens, ED Trudell, ML Pagoria, PF TI Synthesis of 1-substituted [1,2,3]triazolo[4,5-d]pyridazines as precursors for novel tetraazapentalene derivatives SO JOURNAL OF HETEROCYCLIC CHEMISTRY LA English DT Article AB A series of 1-substituted 4,5-diformyl-[1,2,3]triazole derivatives were prepared by 1,3-dipolar cycloaddition of aryl azides with acetylene dicarboxaldehyde mono-diethylacetal. The triazoles were readily converted into 1-substituted [1,2,3]triazolo[4,5-6]pyridazines in good yields. The 1-(2-nitrophenyl)-[1,2,3]triazolo[4,5-d]pyridazine was found to be a useful intermediate for the generation of the novel SH-benzo[1,2,3]triazolo[1',2':1,2]triazolo[4,5-d]pyridazin-6-ium inner salt ring system. C1 Univ New Orleans, Dept Chem, New Orleans, LA 70148 USA. Lawrence Livermore Natl Lab, Energet Mat Ctr, Livermore, CA 94550 USA. RP Trudell, ML (reprint author), Univ New Orleans, Dept Chem, New Orleans, LA 70148 USA. NR 18 TC 8 Z9 8 U1 1 U2 3 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0022-152X J9 J HETEROCYCLIC CHEM JI J. Heterocycl. Chem. PD NOV-DEC PY 2000 VL 37 IS 6 BP 1597 EP 1602 PG 6 WC Chemistry, Organic SC Chemistry GA 397NC UT WOS:000166700900031 ER PT J AU Dueker, SR Lin, YM Buchholz, BA Schneider, PD Lame, MW Segall, HJ Vogel, JS Clifford, AJ AF Dueker, SR Lin, YM Buchholz, BA Schneider, PD Lame, MW Segall, HJ Vogel, JS Clifford, AJ TI Long-term kinetic study of beta-carotene, using accelerator mass spectrometry in an adult volunteer SO JOURNAL OF LIPID RESEARCH LA English DT Article DE vitamin A; human; isotope ID LOW-DENSITY LIPOPROTEINS; VITAMIN-A METABOLISM; PERFORMANCE LIQUID-CHROMATOGRAPHY; TRIGLYCERIDE-RICH LIPOPROTEINS; CHYLOMICRON REMNANT CLEARANCE; RETINYL ESTERS; ATRAZINE METABOLITES; CANCER PREVENTION; ALPHA-TOCOPHEROL; PLASMA-CLEARANCE AB We present a sensitive tracer method, suitable for in vivo human research, that uses beta-[C-14]carotene coupled with accelerator mass spectrometry (AMS) detection. Using this approach, the concentration-time course of a physiological (306 mug; 200 nCi) oral dose of beta-[C-14]carotene was determined for 209 days in plasma. Analytes included beta-[C-14]carotene, [C-14]retinyl esters, [C-14]retinol, and several [C-14]retinoic acids. There was a 5.5-h lag between dosing and the appearance of C-14 in plasma. Labeled beta -carotene and [C-14]retinyl esters rose and displayed several maxima with virtually identical kinetic profiles over the first 24-h period; elevated [C-14]retinyl ester concentrations were sustained in the plasma compartment for >21 h postdosing. The appearance of [C-14]retinol in plasma was also delayed 5.5 h postdosing and its concentration rose linearly for 28 h before declining. Cumalative urine and stool were collected for 17 and 10 days, respectively and 57.4% of the dose was recovered in the stool within 48 h postdosing. The stool was the major excretion route for the absorbed dose. The turnover times (I/k(el)) for beta -carotene and retinol were 58 and 302 days, respectively. Area under the curve analysis of the plasma response curves suggested a molar vitamin A value of 0.53 for beta -carotene, with a minimum of 62% of the absorbed beta -carotene being cleaved to vitamin A. In summary, AMS is an excellent tool for defining the in vivo metabolic behavior of beta -carotene and related compounds at physiological concentrations. Further, our data suggest that retinyl esters derived from beta -carotene may undergo hepatic resecretion with VLDL in a process similar to that observed for beta -carotene. C1 Univ Calif Davis, Dept Nutr, Davis, CA 95616 USA. Univ Calif Davis, Dept Mol Biosci, Davis, CA 95616 USA. Univ Calif Davis, Med Ctr, Ctr Canc, Sacramento, CA 95817 USA. Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94551 USA. RP Dueker, SR (reprint author), Univ Calif Davis, Dept Nutr, Davis, CA 95616 USA. RI Buchholz, Bruce/G-1356-2011 FU NIDDK NIH HHS [DK45939, DK48307] NR 67 TC 63 Z9 64 U1 0 U2 8 PU LIPID RESEARCH INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0022-2275 J9 J LIPID RES JI J. Lipid Res. PD NOV PY 2000 VL 41 IS 11 BP 1790 EP 1800 PG 11 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 372FC UT WOS:000165222800009 PM 11060348 ER PT J AU Franco-Puntes, V Batlle, X Labarta, A AF Franco-Puntes, V Batlle, X Labarta, A TI Domain structures and training effects in granular thin films SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article; Proceedings Paper CT 3rd EruoConference on Magnetic Properties of Fine Particles and Their Relevance to Materials Science CY OCT 19-22, 1999 CL BARCELONA, SPAIN SP European Commiss, Minist Educ & Culture, Univ Barcelona, Vicerectorat Recerca, Univ Barcelona, Div Ciencies Exptl Math, Comiss Univ Recerca, Gen Catalunya, Univ Barcelona, Dept Fis Fonamental, Fac Fis, Grp Magnetisme Propietats Transport DE MFM; magnetoresistance; granular alloys; training effects ID GIANT MAGNETORESISTANCE; TRANSPORT-PROPERTIES; ALLOYS; SYSTEMS AB Magnetic force microscopy (MFM) evidenced that sputtered CoFe-Ag(Cu) granular films displayed long-range magnetic domain structures (magnetic percolation) at ferromagnetic (FM) volume contents, x(nu), well below the volume percolation threshold. A variety of remanent magnetic microstructures was observed as a function of the thermomagnetic history, which strongly condition both magnetic and transport properties. These microstructures are formed due to the competition between perpendicular anisotropy and dipolar and matrix-mediated exchange interactions. All as-deposited samples displayed a high degree of [111] texture perpendicular to the film plane and a rhombohedral distortion induced by film-substrate strains, which are suggested to be at the origin of the observed perpendicular uniaxial anisotropy. Structural data indicate a 2% of CoFe is alloyed to the metallic matrix, which seems to be enough to couple the FM particles when they are closer than 1.5 nm at x(nu) greater than or equal to 25, leading to magnetic percolation. These FM correlations among particles were well evidenced in the low-field susceptibility measurements, which supports the hypothesis that exchange correlations propagate due to the CoFe spins diluted in the matrix. Annealing relaxed the rhombohedral distortion, leading to a cubic anisotropy along the [100] axis of the CoFe cell. Besides, annealing caused the segregation of the CoFe spins alloyed to the matrix, and consequently, the domain structure was lost. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Barcelona, Fac Fis, Dept Fis Fonamental, Barcelona 08028, Spain. RP Franco-Puntes, V (reprint author), Lawrence Berkeley Lab, NCEM, 1 Cyclotron Rd, Berkeley, CA 94720 USA. RI Labarta, Amilcar/B-4539-2012; Batlle, Xavier/H-5795-2012; Puntes, Victor/F-8407-2013 OI Labarta, Amilcar/0000-0003-0904-4678; Puntes, Victor/0000-0001-8996-9499 NR 24 TC 6 Z9 6 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD NOV PY 2000 VL 221 IS 1-2 BP 45 EP 56 DI 10.1016/S0304-8853(00)00371-1 PG 12 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 369XK UT WOS:000165092900007 ER PT J AU Dobrovitski, VV Katsnelson, MI Harmon, BN AF Dobrovitski, VV Katsnelson, MI Harmon, BN TI Statistical coarse-graining as an approach to multiscale problems in magnetism SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Letter DE multiscale problems; coarse graining; micromagnetism; spin dynamics ID MAGNETIZATION REVERSAL; DYNAMICS AB Multiscale phenomena which include several processes occurring simultaneously at different length scales and exchanging energy with each other, are widespread in magnetism. These phenomena often govern the magnetization reversal dynamics, and their correct modeling is important. In the present paper. we propose an approach to multiscale modeling of magnets, applying the ideas of coarse graining. We have analyzed the choice of the weighing function used in coarse graining, and propose an optimal form for this function. Simple tests provide evidence that this approach may be useful for modeling of realistic magnetic systems, (C)) 2000 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames Lab, Ames, IA 50011 USA. RP Dobrovitski, VV (reprint author), Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames Lab, Ames, IA 50011 USA. RI Katsnelson, Mikhail/D-4359-2012 NR 25 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD NOV PY 2000 VL 221 IS 3 BP L235 EP L242 DI 10.1016/S0304-8853(00)00492-3 PG 8 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 389KL UT WOS:000166237100001 ER PT J AU Thiele, JD Melkote, SN Peascoe, RA Watkins, TR AF Thiele, JD Melkote, SN Peascoe, RA Watkins, TR TI Effect of cutting-edge geometry and workpiece hardness on surface residual stresses in finish hard turning of AISI 52100 steel SO JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article ID INTEGRITY AB An experimental investigation was conducted to determine the effects of tool cutting-edge geometry (edge preparation) and workpiece hardness on surface residual stresses for finish hard turning of through-hardened AISI 52100 steel. Polycrystalline cubic boron nitride (PCBN) inserts with representative types of edge geometry including "up-sharp" edges, edge hones, and chamfers were used as the cutting tools in this study. This study shows that tool edge geometry is highly influential with respect to surface residual stresses, which were measured using x-ray diffraction. In general, compressive surface residual stresses in the axial and circumferential directions were generated by large edge hone tools in longitudinal turning operations. Residual stresses in the axial and circumferential directions generated by large edge hone tools are typically more compressive than stresses produced by small edge hone tools. Microstructural analysis shows that thermally-induced phase transformation effects are present at all feeds and workpiece hardness values with the large edge hone tools, and only at high feeds and hardness values with the small edge hone tools. In general, continuous while layers on the workpiece surface correlate with compressive residual stresses, while over-tempered regions correlate with tensile or compressive residual stresses depending on the workpiece hardness. C1 Georgia Inst Technol, George W Woodruff Sch Mech Engn, Atlanta, GA 30332 USA. Oak Ridge Natl Lab, High Temp Mat Lab, Oak Ridge, TN 37831 USA. RP Melkote, SN (reprint author), Georgia Inst Technol, George W Woodruff Sch Mech Engn, Atlanta, GA 30332 USA. RI Watkins, Thomas/D-8750-2016 OI Watkins, Thomas/0000-0002-2646-1329 NR 39 TC 58 Z9 60 U1 0 U2 9 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 1087-1357 J9 J MANUF SCI E-T ASME JI J. Manuf. Sci. Eng.-Trans. ASME PD NOV PY 2000 VL 122 IS 4 BP 642 EP 649 DI 10.1115/1.1286369 PG 8 WC Engineering, Manufacturing; Engineering, Mechanical SC Engineering GA 404PQ UT WOS:000167109900005 ER PT J AU Xu, Y Chumbley, LS Laabs, FC AF Xu, Y Chumbley, LS Laabs, FC TI Liquid metal extraction of Nd from NdFeB magnet scrap SO JOURNAL OF MATERIALS RESEARCH LA English DT Article AB This research involves using molten magnesium (Mg) to remove neodymium (Nd) from NdFeB magnet scrap by diffusion. Mg was melted over pieces of NdFeB scrap and held at temperatures in the range 675-705 degreesC for 2-8 h. The Mg was allowed to solidify, and the castings were then sectioned and characterized using scanning electron microscopy, x-ray diffraction, and chemical analysis. Nd was found to have diffused out of the solid scrap into the molten Mg. The thickness of the diffusion layer was measured, the diffusion of Nd through the NdFeB scrap into liquid Mg was described, and the diffusion coefficient of Nd in liquid Mg was estimated. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. RP Xu, Y (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 12 TC 41 Z9 43 U1 0 U2 10 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 NOV PY 2000 VL 15 IS 11 BP 2296 EP 2304 DI 10.1557/JMR.2000.0330 PG 9 WC Materials Science, Multidisciplinary SC Materials Science GA 373EL UT WOS:000165275400007 ER PT J AU Yuan, Y Gregg, BA Lawrence, MF AF Yuan, Y Gregg, BA Lawrence, MF TI Time-of-flight study of electrical charge mobilities in liquid-crystalline zinc octakis(beta-octoxyethyl) porphyrin films SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID PHTHALOCYANINE THIN-FILMS; POLYMER-ZNTPP/AU CELLS; CHLOROALUMINUM PHTHALOCYANINE; HOLE MOBILITIES; TRANSPORT; DEPENDENCE; DISORDER; CARRIERS AB Time-of-flight measurements performed on micron-thick films of liquid-crystalline zinc octakis(beta -octoxyethyl) porphyrin indicated that charge carriers possess significantly high drift mobilities, attaining approximately 0.01 cm(2) V(-1)s(-1) and 0.008 cm(2) V(-1)s(-1) for holes and electrons, respectively, at room temperature. Upon heating the samples from 300 to 420 K, causing the porphyrin to go from the solid-crystalline to the discotic mesophase, the mobilities did not decrease drastically, and remained at values slightly larger than half those observed at room temperature. Charge transport in this material conformed to the Scher-Montroll model, which attributes a distribution of hopping times to the propagation of the initially formed charged carrier packet. Analysis of the "universal" plots prescribed by this model yielded a dispersion factor of 0.5 for both charge carriers. C1 Concordia Univ, Dept Chem & Biochem, Montreal, PQ H3G 1M8, Canada. Natl Renewable Energy Lab, Div Basic Sci, Golden, CO 80401 USA. RP Lawrence, MF (reprint author), Concordia Univ, Dept Chem & Biochem, 1455 Maisonneuve W, Montreal, PQ H3G 1M8, Canada. NR 41 TC 24 Z9 24 U1 0 U2 3 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD NOV PY 2000 VL 15 IS 11 BP 2494 EP 2498 DI 10.1557/JMR.2000.0358 PG 5 WC Materials Science, Multidisciplinary SC Materials Science GA 373EL UT WOS:000165275400035 ER PT J AU Cook, BA Yudin, VE Otaigbe, JU AF Cook, BA Yudin, VE Otaigbe, JU TI Thermal properties of polyimide foam composites SO JOURNAL OF MATERIALS SCIENCE LETTERS LA English DT Article C1 Iowa State Univ Sci & Technol, Dept Mat Sci & Engn, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Chem Engn, Ames, IA 50011 USA. RP Otaigbe, JU (reprint author), Iowa State Univ Sci & Technol, Dept Mat Sci & Engn, Ames, IA 50011 USA. NR 7 TC 7 Z9 7 U1 1 U2 8 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 NOV PY 2000 VL 19 IS 21 BP 1971 EP 1973 DI 10.1023/A:1006752625555 PG 3 WC Materials Science, Multidisciplinary SC Materials Science GA 369WK UT WOS:000165090600025 ER PT J AU Prasad, SV Nainaparampil, JJ Zabinski, JS AF Prasad, SV Nainaparampil, JJ Zabinski, JS TI Lubricious zinc oxide films grown by pulsed laser deposition: Lateral force microscopy of wear surfaces SO JOURNAL OF MATERIALS SCIENCE LETTERS LA English DT Article ID TRIBOLOGICAL BEHAVIOR; TEMPERATURE C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Systran Fed Corp, Dayton, OH 45432 USA. USAF, Res Lab, MLBT, Wright Patterson AFB, OH 45433 USA. RP Prasad, SV (reprint author), Sandia Natl Labs, POB 5800,MS 1407, Albuquerque, NM 87185 USA. NR 10 TC 7 Z9 7 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 NOV PY 2000 VL 19 IS 22 BP 1979 EP 1981 DI 10.1023/A:1026790330643 PG 3 WC Materials Science, Multidisciplinary SC Materials Science GA 386AE UT WOS:000166036700002 ER PT J AU Boyd, JK AF Boyd, JK TI Probability amplitude dynamics for a two-level system (vol 41, pg 4330, 2000) SO JOURNAL OF MATHEMATICAL PHYSICS LA English DT Correction C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Boyd, JK (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808 L-095, Livermore, CA 94551 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0022-2488 J9 J MATH PHYS JI J. Math. Phys. PD NOV PY 2000 VL 41 IS 11 BP 7883 EP 7883 DI 10.1063/1.1322079 PG 1 WC Physics, Mathematical SC Physics GA 366DU UT WOS:000089990200042 ER PT J AU Potter, BG Simmons-Potter, K Dunbar, TD AF Potter, BG Simmons-Potter, K Dunbar, TD TI Thermal stability of photosensitive Bragg gratings in sputter-deposited germanosilicate glass SO JOURNAL OF NON-CRYSTALLINE SOLIDS LA English DT Article ID THIN-FILMS; EXCIMER-LASER; HIGH-PRESSURE; RAMAN; DEFECTS; FIBERS AB The thermal stability of photo-imprinted Bragg gratings formed in reactive-atmosphere, RF-magnetron sputtered germanosilicate thin films was evaluated in terms of point defect modifications observed during isochronal annealing. Optical and magnetic spectroscopies were utilized to evaluate structural relaxation in these sputtered glasses on both the local and medium-range size scale. Depending upon the substrate temperature used during deposition, significant structural rearrangement was found to occur with increasing post-deposition anneal temperature to 600 degreesC. This resulted in changes in the photobleaching response of the material itself as the identity of optically active structural defects evolved. Based on a color center model for photosensitivity in these materials and measured changes in optical absorption with annealing, the thermal stability of a photo-imprinted Bragg grating was modeled. Good qualitative agreement with experiment was observed. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Potter, BG (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 20 TC 3 Z9 4 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3093 J9 J NON-CRYST SOLIDS JI J. Non-Cryst. Solids PD NOV PY 2000 VL 277 IS 2-3 BP 114 EP 126 DI 10.1016/S0022-3093(00)00305-7 PG 13 WC Materials Science, Ceramics; Materials Science, Multidisciplinary SC Materials Science GA 381DB UT WOS:000165746100006 ER PT J AU Miller, MK Russell, KF Kocik, J Keilova, E AF Miller, MK Russell, KF Kocik, J Keilova, E TI Embrittlement of low copper VVER 440 surveillance samples neutron-irradiated to high fluences SO JOURNAL OF NUCLEAR MATERIALS LA English DT Letter AB An atom probe tomography microstructural characterization of low copper (0.06 at.% Cu) surveillance samples from a VVER 440 reactor has revealed manganese and silicon segregation to dislocations and other ultrafine features in neutron-irradiated base and weld materials (fluences 1 x 10(25) m(-2) and 5 x 10(24) m(-2), E > 0.5 MeV, respectively). The results indicate that there is an additional mechanism of embrittlement during neutron irradiation that manifests itself at high fluences. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Met & Ceram, Microscopy & Microanalyt Sci Grp, Oak Ridge, TN 37831 USA. Nucl Res Inst Rez Plc, Prague 25068, Czech Republic. RP Miller, MK (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, Microscopy & Microanalyt Sci Grp, Bldg 4500 S,MS 6136,POB 2008, Oak Ridge, TN 37831 USA. NR 13 TC 45 Z9 48 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD NOV PY 2000 VL 282 IS 1 BP 83 EP 88 DI 10.1016/S0022-3115(00)00240-3 PG 6 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 367NC UT WOS:000090067500008 ER PT J AU Ghandehari, K Akella, J Weir, ST Ruddle, CA AF Ghandehari, K Akella, J Weir, ST Ruddle, CA TI Phase stability and EOS of orthorhombic high-pressure phase of NaI to 204 GPa SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article DE X-ray diffraction; phase transitions; equations-of-state ID CRYSTAL-STRUCTURE; HYDRIDE; CSH AB X-ray diffraction studies fur the alkali halide, NaI, were performed to 204 GPa at room temperature. We observed that the TLI (B33) high-pressure phase, which has been reported to succeed the B1 phase for NaI around 30 Cpa, is stable to a pressure of at least 204 Cpa. The measured relative volume, V/V-0, at 204 Cpa is 0.366. We present data for the EOS of NaI in the B33 phase between 35 and 204 Cpa. No data has been previously reported to this pressure. The EOS determined in the present study will be useful in predicting theoretically if a higher packing density B2 phase exists at still higher pressures and if an insulator-metal transition occurs in the B33 phase stability region or in some other succeeding high-pressure phase region. Published by Elsevier Science Ltd. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Akella, J (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 5508, Livermore, CA 94550 USA. RI Weir, Samuel/H-5046-2012 NR 16 TC 2 Z9 4 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD NOV PY 2000 VL 61 IS 11 BP 1883 EP 1887 DI 10.1016/S0022-3697(00)00072-X PG 5 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA 353XE UT WOS:000089300100021 ER PT J AU Green, D Maeshima, K Marrafino, J Vidal, R Womersley, J Wu, W Kunori, S AF Green, D Maeshima, K Marrafino, J Vidal, R Womersley, J Wu, W Kunori, S TI Search for the standard model Higgs boson with M-H0 approximate to 170 GeV c(-2) in W+W- decay mode SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Article AB This note summarizes the results of a study of the identification of the H-0 --> W+W- --> l(+l)'(-)upsilon (l)<()over bar>(l') signal for M(H)0 = 170 GeV c(-2). This study is motivated by the papers written by Dittmar and Dreiner. We carried out a similar study using Pythia to generate events and a CMSIM calorimeter simulation for the jet veto, and compared with their results. We also show some comparison between Pythia- and ISAJET-generated events for this process. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Maryland, College Pk, MD 20742 USA. RP Green, D (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 4 TC 6 Z9 6 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0954-3899 J9 J PHYS G NUCL PARTIC JI J. Phys. G-Nucl. Part. Phys. PD NOV PY 2000 VL 26 IS 11 BP 1751 EP 1764 DI 10.1088/0954-3899/26/11/309 PG 14 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 374LW UT WOS:000165347500010 ER PT J AU Pak, J Wunderlich, B AF Pak, J Wunderlich, B TI Thermal analysis of paraffins as model compounds for polyethylene SO JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS LA English DT Article; Proceedings Paper CT Meeting of the Division of Polymer Physics of the American-Physical-Society CY MAR, 2000 CL MINNEAPOLIS, MINNESOTA SP Amer Phys Soc, Div Polymer Phys DE temperature-modulated differential scanning calorimetry; supercooling; melting; crystallization; isotropization; disordering; paraffin; C50H102; C44H90; C26H54; polyethylene; fractions ID DIFFERENTIAL SCANNING CALORIMETRY; TEMPERATURE-MODULATED CALORIMETRY; SPHERULITIC GROWTH; HEAT-CAPACITY; CRYSTALLIZATION; CRYSTALS; DSC; TRANSITIONS; FRACTIONS; POLYMERS AB The n-paraffins C50H102, C44H90, and C26H54 were analyzed with standard and temperature-modulated differential scanning calorimetry. Crystallization and ordering from the melt to the condis phase showed practically no supercooling. These observations were confirmed with hot-stage microscopy and a melting-point apparatus. Only the organization of the C26H54 condis crystals to fully ordered crystals showed a supercooling of 4.0 K. The measurement of the apparent reversing heat capacity with a 0.05-K modulation amplitude revealed that the melting of C50H102 was completed within 1.0 K and the isotropization of C26H54 was completed within less than 0.6 IC, but 62-78% of the total transitions occurred over a much narrower temperature range of 0.1 K or less. The link to polyethylene was made with fractions of the masses 15, 520, 2150, and 560 Da. The 560-Da sample corresponded to C40H82 and showed also almost no supercooling, whereas the others, with folded and extended-chain crystals, supercooled by about 10 K. (C) 2000 John Wiley & Sons, Inc. C1 Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Wunderlich, B (reprint author), Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. NR 39 TC 26 Z9 26 U1 1 U2 7 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0887-6266 J9 J POLYM SCI POL PHYS JI J. Polym. Sci. Pt. B-Polym. Phys. PD NOV 1 PY 2000 VL 38 IS 21 BP 2810 EP 2822 DI 10.1002/1099-0488(20001101)38:21<2810::AID-POLB100>3.0.CO;2-C PG 13 WC Polymer Science SC Polymer Science GA 363KZ UT WOS:000089836000010 ER PT J AU Hakem, NL Al Mahamid, I Apps, JA Moridis, GJ AF Hakem, NL Al Mahamid, I Apps, JA Moridis, GJ TI Sorption of cesium and strontium on Hanford soil SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article ID MINERALS; CLAYS AB The sorption behavior of strontium and cesium on soil collected from the US Department of Energy Hanford site, Washington State, was investigated under batch experiments. The sorption ratio was determined as a function of time and radionuclide concentration. All experiments were performed at 25 degreesC under argon atmosphere. Cesium and strontium were extensively sorbed on the soil. The sorption data were well described by a Freundlich isotherm. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Hakem, NL (reprint author), Univ Calif Lawrence Livermore Natl Lab, GT Seaborg Inst Transactium Sci, POB 808,L-231, Livermore, CA 94551 USA. NR 9 TC 14 Z9 15 U1 0 U2 3 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD NOV PY 2000 VL 246 IS 2 BP 275 EP 278 DI 10.1023/A:1006701902891 PG 4 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 375EZ UT WOS:000165387700005 ER PT J AU Silver, GL AF Silver, GL TI The auto-reduction of hexavalent Pu-239 in acid solution SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article ID PLUTONIUM AB Historical measurements on the alpha-particle reduction of hexavalent Pu-239 can be interpreted as a succession of near-equilibrium steps. The phenomenon can be simulated by plotting the distribution of the oxidation states for decreasing values of the Pu oxidation number. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Silver, GL (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663,MS E502, Los Alamos, NM 87545 USA. NR 8 TC 6 Z9 6 U1 0 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD NOV PY 2000 VL 246 IS 2 BP 429 EP 430 DI 10.1023/A:1006784221063 PG 2 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 375EZ UT WOS:000165387700031 ER PT J AU Gehrke, RJ AF Gehrke, RJ TI Artifact (alpha, x) reaction gamma-ray peaks reported as Am-241 decay gamma-rays - Comments to the paper by Abdulrahman Abdul-Hadi, J. Radioanal. Nucl. Chem., 231 (1998) 147. SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article AB Review of a recent paper reporting the gamma -ray energies and intensities associated with the decay of Am-241 has resulted in the conclusion that some of the gamma rays were misidentified. The misidentified gamma -rays are not associated with the decay of Am-241, but rather are prompt gamma -rays from alpha-induced reactions. C1 Bechtel BWXT Idaho LLC, Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Gehrke, RJ (reprint author), Bechtel BWXT Idaho LLC, Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. NR 7 TC 2 Z9 2 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD NOV PY 2000 VL 246 IS 2 BP 449 EP 450 DI 10.1023/A:1006748607859 PG 2 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 375EZ UT WOS:000165387700037 ER PT J AU Guedes, I Mitchell, JF Argyriou, D Grimsditch, M AF Guedes, I Mitchell, JF Argyriou, D Grimsditch, M TI Raman phonons in La2-2xSr1+2xMn2O7 layered manganites SO JOURNAL OF RAMAN SPECTROSCOPY LA English DT Article ID SINGLE-CRYSTALS; SCATTERING; LA1.2SR1.8MN2O7; SPECTROSCOPY; PYROCHLORE; PEROVSKITE; LAMNO3 AB Phonons of polycrystalline La2-2xSr1+2xMn2O7 (0.38 less than or equal to x less than or equal to 1.0) ceramic samples were studied at room temperature using Raman spectroscopy. The spectra are consistent with the group theory predictions for a body-centered tetragonal crystal structure (D-4h(17)). Since no appreciable changes were observed in the Raman spectra for different extents of La doping, this suggests that the layered manganite structure is less sensitive to dopants than that of the related three-dimensional perovskites. Copyright (C) 2000 John Wiley & Sons, Ltd. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. UFC, Dept Fis, BR-60455760 Fortaleza, Ceara, Brazil. RP Guedes, I (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI GUEDES, ILDE/C-3451-2013; UFC, DF/E-1564-2017; Universidade Federal do Ceara, Physics Department/J-4630-2016; Amado, Ana Margarida/M-9097-2013 OI Universidade Federal do Ceara, Physics Department/0000-0002-9247-6780; Amado, Ana Margarida/0000-0002-7572-0980 NR 16 TC 2 Z9 2 U1 0 U2 5 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0377-0486 J9 J RAMAN SPECTROSC JI J. Raman Spectrosc. PD NOV PY 2000 VL 31 IS 11 BP 1013 EP 1015 DI 10.1002/1097-4555(200011)31:11<1013::AID-JRS637>3.0.CO;2-9 PG 3 WC Spectroscopy SC Spectroscopy GA 376LM UT WOS:000165459100009 ER PT J AU May, K Barker, G Hancock, E Walker, A Dominick, J Westby, B AF May, K Barker, G Hancock, E Walker, A Dominick, J Westby, B TI Performance of a large parabolic trough solar water heating system at Phoenix Federal Correctional Institution SO JOURNAL OF SOLAR ENERGY ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article AB Phoenix Federal Correctional Institution in Arizona, the Federal Bureau of Prisons (FBP) completed a 1,584 m(2) (17,040 square feet) parabolic trough solar water heating system financed installed and operated under an Energy Savings performance Contract (ESPC) with Industrial Solar Technology Corp (IST). The ESPC was developed under a Cooperative Research and Development Agreement with the National Renewable Energy Laboratory (NREL). The system incorporates a 87 m(3) (23,000 gallon) storage tank. The system delivered 1,161,803 kWh (3,964 million Btu) of solar heat from March 1, 1999 to February 29, 2000. This energy would have cost $77,805.74 if purchased from the utility (based on the monthly average $/kWh cost). Sale of this energy to the prison provided $70,025.18 in revenue to IST (a rate negotiated at 90 percent of the monthly average $/kWh utility cost). Thus, the prison saved $7,780.56 (the remaining 10 percent). A photograph of the collector system is presented in Figure I. Results show that the system delivers hear reliably, with only minor operational problems which are listed and discussed. The system delivered a minimum of 80,315 kWh (274 Btu) in January 2000 to a maximum of 130,979 kWh (447 Million Btu) in October 1999. The prison pays IST for energy delivered by the solar system at a rate equal to 90 percent of the monthly average utility rate (10 percent guaranteed savings), over 20 years. Details of the establishment of the payment structure and the cost savings to the prison are discussed. Annual Emissions Savings are estimated by EPA multipliers [1] for Arizona as 627,374 kg/yr of CO2, 2,324 kg/yr of SO2 and 2,297 kg/yr of NOx. Other benefits to the prison are also discussed, such as reduced operations and maintenance on the electric water hearers and a greater capacity to deliver hot water. [S0199-6231(00)00704-8]. C1 Ind Solar Technol Corp, Golden, CO 80403 USA. Mt Energy Partners, Boulder, CO 80304 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP May, K (reprint author), Ind Solar Technol Corp, 4420 McIntyre St, Golden, CO 80403 USA. NR 4 TC 5 Z9 5 U1 2 U2 6 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0199-6231 J9 J SOL ENERG-T ASME JI J. Sol. Energy Eng. Trans.-ASME PD NOV PY 2000 VL 122 IS 4 BP 165 EP 169 DI 10.1115/1.1331288 PG 5 WC Energy & Fuels; Engineering, Mechanical SC Energy & Fuels; Engineering GA 404NC UT WOS:000167105800001 ER PT J AU Paschoal, CWA Moura, MR Ayala, AP Sasaki, JM Freire, PTC Melo, FEA Mendes, J Guedes, I Leyva, AG Polla, G Vega, D Perazzo, PK AF Paschoal, CWA Moura, MR Ayala, AP Sasaki, JM Freire, PTC Melo, FEA Mendes, J Guedes, I Leyva, AG Polla, G Vega, D Perazzo, PK TI Temperature-dependent Raman study of CaCu(HCOO)(4) and Ca2Cu(HCOO)(6) crystals SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article ID VIBRATIONAL-SPECTRA; COPPER(II) FORMATES; THERMAL-BEHAVIOR; CU(HCOO)2.2H2O; NAHCOO AB Unpolarized Raman spectra of policrystalline samples of calcium (II)-copper (II) formate [CaCu(HCOO)(4)] and dicalcium (II)-copper (II) formate [Ca2Cu(HCOO)(6)] were recorded and analyzed in the temperature range from 30 to 300 K, The observed modes at 300 K were assigned on the basis of formate group vibrations and correlations with previous data reported for other formate compounds, The splitting of the internal HCOO modes agrees with the group theory predictions. No changes either in the wavenumber or intensity of Raman modes were observed when the temperature of the samples was cooled to 30 K, This indicates that these compounds do no exhibit any phase transformation in the temperature range investigated. (C) 2000 Academic Press. C1 Univ Fed Ceara, Dept Fis, BR-60451970 Fortaleza, Ceara, Brazil. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Comis Nacl Energia Atom, Dept Fis, RA-1429 Buenos Aires, DF, Argentina. RP Paschoal, CWA (reprint author), Univ Fed Ceara, Dept Fis, Caixa Postal 6030, BR-60451970 Fortaleza, Ceara, Brazil. RI GUEDES, ILDE/C-3451-2013; Freire, Paulo/C-5229-2013; Mendes Filho, Josue/K-7083-2013; Melo, Francisco/J-2596-2014; Paschoal, William/A-5779-2013; UFC, DF/E-1564-2017; Ayala, Alejandro/A-7518-2008; Universidade Federal do Ceara, Physics Department/J-4630-2016; OI Freire, Paulo/0000-0002-2321-3709; Paschoal, William/0000-0001-9055-387X; Ayala, Alejandro/0000-0002-9247-6780; Universidade Federal do Ceara, Physics Department/0000-0002-9247-6780; GUEDES, ILDE/0000-0002-1040-5891 NR 23 TC 5 Z9 5 U1 0 U2 6 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD NOV 1 PY 2000 VL 154 IS 2 BP 338 EP 343 DI 10.1006/jssc.2000.8791 PG 6 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA 378ZW UT WOS:000165617300003 ER PT J AU Shaked, H Jorgensen, JD Chmaissem, O Ikeda, S Maeno, Y AF Shaked, H Jorgensen, JD Chmaissem, O Ikeda, S Maeno, Y TI Neutron diffraction study of the structural distortions in Sr3Ru2O7 SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article DE bilayered perovskites; structural distortions; Sr3Ru2O7; neutron diffraction ID CRYSTAL-STRUCTURE; MAGNETORESISTANCE; COMPOUND AB It is shown that due to the ionic sizes of Sr2+ and Ru4+, crystal structure distortions are expected in the layered structure of Sr3Ru2O7. Using neutron powder diffraction of Sr3Ru2O7, the expected distortions are indeed found and their nature is studied at roam temperature, It is found that among the eight possible modes of pure rotations (i,e,, rotations along symmetry axes) of the oxygen octahedra, only one mode is consistent with the neutron data, In this mode the octahedra rotate about the c axis with intra- and interbilayer order. This ordered model is in contrast to a previously reported semi-ordered model, where the rotations in every other bilayer have interbilayer disorder. (C) 2000 Academic Press. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. No Illinois Univ, Dept Phys, De Kalb, IL 60115 USA. Kyoto Univ, Dept Phys, Kyoto 6068502, Japan. Japan Sci & Technol Corp, Core Res Evolutionary Sci, Kawaguchi, Saitama 3320012, Japan. Ben Gurion Univ Negev, Dept Phys, IL-84190 Beer Sheva, Israel. Electrotech Lab, Div Phys Sci, Tsukuba, Ibaraki 3058568, Japan. RP Shaked, H (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Ikeda, Shinichi/I-5829-2012 OI Ikeda, Shinichi/0000-0003-2134-7786 NR 22 TC 76 Z9 76 U1 3 U2 29 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD NOV 1 PY 2000 VL 154 IS 2 BP 361 EP 367 DI 10.1006/jssc.2000.8796 PG 7 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA 378ZW UT WOS:000165617300007 ER PT J AU Hasnain, SS Kamitsubo, H Mills, DM AF Hasnain, SS Kamitsubo, H Mills, DM TI Phase II of the genomic effort SO JOURNAL OF SYNCHROTRON RADIATION LA English DT Editorial Material C1 SERC, Daresbury Lab, CCLRC, Warrington WA4 4AD, Cheshire, England. JASRI, SPring 8, Sayo, Hyogo 6795198, Japan. Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RP Hasnain, SS (reprint author), SERC, Daresbury Lab, CCLRC, Warrington WA4 4AD, Cheshire, England. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0909-0495 J9 J SYNCHROTRON RADIAT JI J. Synchrot. Radiat. PD NOV PY 2000 VL 7 BP 355 EP 355 DI 10.1107/S0909049500013492 PN 6 PG 1 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA 367LN UT WOS:000090063900001 PM 16609220 ER PT J AU Powell, CF Yue, Y Poola, R Wang, J AF Powell, CF Yue, Y Poola, R Wang, J TI Time-resolved measurements of supersonic fuel sprays using synchrotron X-rays SO JOURNAL OF SYNCHROTRON RADIATION LA English DT Article DE fuel sprays; monochromatic radiographs; time-resolved; supersonic liquid jets ID DROPLET AB A time-resolved radiographic technique has been developed for probing the fuel distribution close to the nozzle of a high-pressure single-hole diesel injector. The measurement was made using X-ray absorption of monochromatic synchrotron-generated radiation, allowing quantitative determination of the fuel distribution in this optically impenetrable region with a time resolution of better than 1 mus. These quantitative measurements constitute the most detailed near-nozzle study of a fuel spray to date. C1 Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. Argonne Natl Lab, Div Energy Syst, Argonne, IL 60439 USA. RP Wang, J (reprint author), Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. NR 12 TC 32 Z9 32 U1 0 U2 5 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0909-0495 J9 J SYNCHROTRON RADIAT JI J. Synchrot. Radiat. PD NOV PY 2000 VL 7 BP 356 EP 360 DI 10.1107/S0909049500013431 PN 6 PG 5 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA 367LN UT WOS:000090063900002 PM 16609221 ER PT J AU Winn, B Ade, H Buckley, C Feser, M Howells, M Hulbert, S Jacobsen, C Kaznacheyev, K Kirz, J Osanna, A Maser, J McNulty, I Miao, J Oversluizen, T Spector, S Sullivan, B Wang, Y Wirick, S Zhang, H AF Winn, B Ade, H Buckley, C Feser, M Howells, M Hulbert, S Jacobsen, C Kaznacheyev, K Kirz, J Osanna, A Maser, J McNulty, I Miao, J Oversluizen, T Spector, S Sullivan, B Wang, Y Wirick, S Zhang, H TI Illumination for coherent soft X-ray applications: the new X1A beamline at the NSLS SO JOURNAL OF SYNCHROTRON RADIATION LA English DT Article DE beamlines; microscopy; coherence; soft X-rays; undulators ID SYNCHROTRON RADIATION; HOLOGRAPHIC MICROSCOPY; LASER; SPECTROSCOPY; PERFORMANCE; RESOLUTION; UNDULATOR AB The X1A soft X-ray undulator beamline at the NSLS has been rebuilt to serve two microscopy stations operating simultaneously. Separate spherical-grating monochromators provide the resolving power required for XANES spectroscopy at the C, N and O absorption edges. The exit slits are fixed and define the coherent source for the experiments. The optical design and the operational performance are described. C1 SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. N Carolina State Univ, Dept Phys, Raleigh, NC 27599 USA. Kings Coll London, Dept Phys, London WC2R 2LS, England. Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source, Berkeley, CA 94720 USA. Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. Creat Instrumentat, E Patchogue, NY 11772 USA. RP Kirz, J (reprint author), SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. EM janos.kirz@sunysb.edu RI Ade, Harald/E-7471-2011; Maser, Jorg/K-6817-2013; Jacobsen, Chris/E-2827-2015; Winn, Barry/A-5065-2016 OI Jacobsen, Chris/0000-0001-8562-0353; Winn, Barry/0000-0001-6383-4318 NR 42 TC 35 Z9 35 U1 0 U2 3 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0909-0495 J9 J SYNCHROTRON RADIAT JI J. Synchrot. Radiat. PD NOV PY 2000 VL 7 BP 395 EP 404 DI 10.1107/S0909049500012942 PN 6 PG 10 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA 367LN UT WOS:000090063900008 PM 16609227 ER PT J AU Naulleau, PP Cho, CH Gullikson, EM Bokor, J AF Naulleau, PP Cho, CH Gullikson, EM Bokor, J TI Transmission phase gratings for EUV interferometry SO JOURNAL OF SYNCHROTRON RADIATION LA English DT Article DE EUV; phase gratings; diffraction; interferometry ID POINT-DIFFRACTION INTERFEROMETER; EXTREME-ULTRAVIOLET AB The performance of the recently developed EUV phase-shifting point diffraction interferometer (PS/ PDI) depends heavily on the characteristics of the grating beamsplitter used in the implementation. Ideally, such a grating should provide throughput of better than 25% and diffraction efficiency, defined as the ratio of the first-diffracted-order power to the zero-order power, variable in the range from approximately 10 to 500. The optimal method for achieving these goals is by way of a phase grating. Also, PS/PDI system implementation issues favor the use of transmission gratings over reflection gratings. Here, the design, fabrication, and characterization of a recently developed transmission phase grating developed for use in EUV interferometry is described. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept EECS, Berkeley, CA 94720 USA. RP Naulleau, PP (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. RI Bokor, Jeffrey/A-2683-2011 NR 11 TC 19 Z9 19 U1 0 U2 1 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0909-0495 J9 J SYNCHROTRON RADIAT JI J. Synchrot. Radiat. PD NOV PY 2000 VL 7 BP 405 EP 410 DI 10.1107/S0909049500010670 PN 6 PG 6 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA 367LN UT WOS:000090063900009 PM 16609228 ER PT J AU Goldberg, LA Mackenzie, PD Paterson, M Srinivasan, A AF Goldberg, LA Mackenzie, PD Paterson, M Srinivasan, A TI Contention resolution with constant expected delay SO JOURNAL OF THE ACM LA English DT Article DE Probability Theory; contention resolution; ethernet; Markov chains; multiple-access channel ID MULTIPLE-ACCESS CHANNELS; COMMUNICATION AB We study contention resolution in a multiple-access channel such as the Ethernet channel. In the model that we consider, n users generate messages for the channel according to a probability distribution. Raghavan and Upfai have given a protocol in which the expected delay (time to get serviced) of every message is O(log n) when messages are generated according to a Bernoulli distribution with generation rate up to about 1/10. Our main results are the following protocols: (a) one in which the expected average message delay is O(1) when messages are generated according to a Bernoulli distribution with a generation rate smaller than lie, and (b) one in which the expected delay of any message is O(1) for an analogous model in which users are synchronized (i.e., they agree about the time), there are potentially an infinite number of users, and messages are generated according to a Poisson distribution with generation rate up to 1/e. (Each message constitutes a new user.) To achieve (a), we first show how to simulate (b) using n synchronized users, and then show how to build the synchronization into the protocol. C1 Univ Warwick, Dept Comp Sci, Coventry CV4 7AL, W Midlands, England. Lucent Technol, Bell Labs, Murray Hill, NJ 07974 USA. Sandia Natl Labs, Livermore, CA 94550 USA. Max Planck Inst Informat, D-66123 Saarbrucken, Germany. Natl Univ Singapore, Sch Comp, Singapore 119260, Singapore. RP Goldberg, LA (reprint author), Univ Warwick, Dept Comp Sci, Coventry CV4 7AL, W Midlands, England. NR 22 TC 17 Z9 17 U1 0 U2 0 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036 USA SN 0004-5411 J9 J ACM JI J. ACM PD NOV PY 2000 VL 47 IS 6 BP 1048 EP 1096 DI 10.1145/355541.355567 PG 49 WC Computer Science, Hardware & Architecture; Computer Science, Information Systems; Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA 394XU UT WOS:000166550300005 ER PT J AU Chinn, RE Haun, MJ Kim, CY Price, DB AF Chinn, RE Haun, MJ Kim, CY Price, DB TI Microstructures and properties of three composites of alumina, mullite, and monoclinic SrAl2Si2O8 SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID FRACTURE-TOUGHNESS; CERAMICS AB Three composites that were 96% alumina were mixed and uniaxially dry-pressed into bars and pellets; all had monoclinic SrAl2Si2O8 as an intergranular phase. The diffraction patterns, microstructure, density, dielectric properties, strength, and toughness were measured, The first composition, which contained crystalline SrCO3, Al2O3, and SiO2, in a 1:1:2 molar ratio, as the 4% component, densified but was generally inferior to the second and third compositions, which contained strontium aluminosilicate (SrAlxSiyOz, SAS) glass as the 4% component, in terms of mechanical properties, defects, and monoclinic SrAl2Si2O8 transformation, The second composition, which lacked B2O3, was very tough and was comparable to commercial alumina, in terms of the dielectric constant. The third, which contained 0.068% of B2O3 that was dissolved in the SAS glass as a sintering aid, had high strength and toughness and no macroscopically visible defects. Mullite formed, in addition to monoclinic SrAl2Si2O8 in all three composites. Alumina-monoclinic SrAl2Si2O8 composites of the third composition had room-temperature properties that were comparable to commercial aluminas that contained 96% alumina and also had potential for mechanical and refractory applications. C1 Colorado Sch Mines, Colorado Ctr Adv Ceram, Golden, CO 80401 USA. RP Chinn, RE (reprint author), US DOE, Albany Res Ctr, Albany, OR 97321 USA. NR 29 TC 7 Z9 7 U1 2 U2 6 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD NOV PY 2000 VL 83 IS 11 BP 2668 EP 2672 PG 5 WC Materials Science, Ceramics SC Materials Science GA 372LR UT WOS:000165235600004 ER PT J AU Garino, T Rodriguez, M AF Garino, T Rodriguez, M TI Behavior of silver and palladium mixtures during heating SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID SUBSOLIDUS PHASE-RELATIONS; SINTERING BEHAVIOR; COMPACTS; SYSTEM; AG AB The behavior of mixtures of silver and palladium during heating in both air and an inert atmosphere was studied using X-ray diffractometry (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dilatometry, and scanning electron microscopy (SEM). In situ high-temperature XRD studies on a commercial 20% palladium material with submicrometer-sized particles indicated that an intermetallic phase, most likely Ag3Pd, formed in air between 300 degrees and 400 degreesC, the same temperature range where a 13% linear expansion was measured by dilatometry. The DSC data indicated an esothermic peak at 340 degreesC, a temperature where the TGA results indicated that the material had picked up only 0.2%, oxygen, compared with the maximum of 1.4% at 525 degreesC. No PdO was detected by XRD at 400 degreesC, which suggests that oxygen was being incorporated in the intermetallic. Microstructural examination using SEM indicated that larger particles, with internal pores, had formed after heating in air to 375 degreesC, When the material was heated in argon for 1h at 400 degreesC, no intermetallic phase or alloy formed, and minimal expansion occurred. When mixtures of larger silver particles (5-30 mum) with palladium particles (1-3 mum) were heated in air, the maximum amount of expansion that occurred increased from 0% for pure palladium up to a maximum of 18% at 75% silver. This result supports the conclusion that expansion is a result of formation of this new phase, in the presence of oxygen, not of the oxidation of the palladium. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Garino, T (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 14 TC 10 Z9 10 U1 1 U2 3 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD NOV PY 2000 VL 83 IS 11 BP 2709 EP 2714 PG 6 WC Materials Science, Ceramics SC Materials Science GA 372LR UT WOS:000165235600013 ER PT J AU Zhang, XF Sixta, ME De Jonghe, LC AF Zhang, XF Sixta, ME De Jonghe, LC TI Grain boundary evolution in hot-pressed ABC-SiC SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID SILICON-NITRIDE CERAMICS; BETA->ALPHA TRANSFORMATION; CARBIDE; GROWTH; FILMS; ADDITIONS; THICKNESS; BEHAVIOR; CREEP; PHASE AB Silicon carbide with aluminum, boron, and carbon additions (ABC-SiC) was hot-pressed to full density, The samples were examined by transmission electron microscopy (TEM), with an emphasis on high-resolution electron microscopy (HREM). Amorphous grain boundary interlayers, typically less than 2 nm wide, were formed between SIC grains. Heat-treating the ABC-SiC at temperatures as low as 1100 degreesC in Ar crystallized the grain boundary interlayers completely without significantly changing the dominant chemical constituents. Chemical microanalyses demonstrated Al and O enrichment for all examined grain boundaries in both as-prepared and annealed samples. Quantitative EDS analyses revealed Al2OC- and Al2O3-related species (with Si, C, B, or S substitutions) as two of the most likely grain boundary interlayer materials, both before and after heat treatment. Al2O3, and (Al1-xSix)(2)OC with a 2H-type wurtzite structure, were identified as grain boundary films by HREM images. The structural evolution in the grain boundary phases during the hot pressing and postannealing is discussed. C1 Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. RP Zhang, XF (reprint author), Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. NR 41 TC 50 Z9 50 U1 2 U2 12 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD NOV PY 2000 VL 83 IS 11 BP 2813 EP 2820 PG 8 WC Materials Science, Ceramics SC Materials Science GA 372LR UT WOS:000165235600029 ER PT J AU Wang, HX Ralston, CY Patil, DS Jones, RM Gu, W Verhagen, M Adams, M Ge, P Riordan, C Marganian, CA Mascharak, P Kovacs, J Miller, CG Collins, TJ Brooker, S Croucher, PD Wang, K Stiefel, EI Cramer, SP AF Wang, HX Ralston, CY Patil, DS Jones, RM Gu, W Verhagen, M Adams, M Ge, P Riordan, C Marganian, CA Mascharak, P Kovacs, J Miller, CG Collins, TJ Brooker, S Croucher, PD Wang, K Stiefel, EI Cramer, SP TI Nickel L-edge soft X-ray spectroscopy of nickel-iron hydrogenases and model compounds - Evidence for high-spin nickel(II) in the active enzyme SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID DESULFOVIBRIO-GIGAS HYDROGENASE; TRANSITION-METAL COMPOUNDS; ABSORPTION-SPECTROSCOPY; CHROMATIUM-VINOSUM; ELECTRONIC-STRUCTURE; NIFE HYDROGENASE; OXIDATIVE TITRATIONS; PYROCOCCUS-FURIOSUS; CATALYTIC MECHANISM; SULFUR CLUSTER AB L-edge X-ray absorption spectroscopy has been used to study, under a variety of conditions, the electronic structure of Ni in the Ni-Fe hydrogenases from Desulfovibrio gigas, Desulfovibrio baculatus, and Pyrococcus furiosus. The status of the enzyme films used for these measurements was monitored by FT-IR spectroscopy. The L-edge spectra were interpreted by ligand field multiplet simulations and by comparison with data for Ni model complexes. The spectrum for Ni in D. gigas enzyme "form A" is consistent with a covalent Ni(III) species. In contrast, all of the reduced enzyme samples exhibited high spin Ni(II) spectra. The significance of the Ni(II) spin state for the structure of the hydrogenase active site is discussed. C1 Univ Calif Davis, Dept Appl Sci, Davis, CA 95616 USA. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Georgia, Dept Biochem, Athens, GA USA. Univ Delaware, Dept Chem, Newark, DE 19716 USA. Univ Calif Santa Cruz, Dept Chem, Santa Cruz, CA 95064 USA. Univ Washington, Dept Chem, Seattle, WA 98195 USA. Carnegie Mellon Univ, Dept Chem, Pittsburgh, PA 15213 USA. Univ Otago, Dept Chem, Dunedin, New Zealand. Exxon Res & Engn Co, Annandale, NJ 08801 USA. RP Cramer, SP (reprint author), Univ Calif Davis, Dept Appl Sci, Davis, CA 95616 USA. RI Riordan, Charles/F-8513-2010; Brooker, Sally/C-3440-2016; Collins, Terrence/A-9807-2017 OI Brooker, Sally/0000-0002-5878-8238; Collins, Terrence/0000-0003-2611-9184 NR 77 TC 87 Z9 87 U1 2 U2 16 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 NOV 1 PY 2000 VL 122 IS 43 BP 10544 EP 10552 DI 10.1021/ja000945g PG 9 WC Chemistry, Multidisciplinary SC Chemistry GA 371XR UT WOS:000165205000006 ER PT J AU Ralston, CY Wang, HX Ragsdale, SW Kumar, M Spangler, NJ Ludden, PW Gu, W Jones, RM Patil, DS Cramer, SP AF Ralston, CY Wang, HX Ragsdale, SW Kumar, M Spangler, NJ Ludden, PW Gu, W Jones, RM Patil, DS Cramer, SP TI Characterization of heterogeneous nickel sites in CO dehydrogenases from Clostridium thermoaceticum and Rhodospirillum rubrum by nickel L-edge X-ray spectroscopy SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID CARBON-MONOXIDE DEHYDROGENASE; MAGNETIC CIRCULAR-DICHROISM; IRON-SULFUR PROTEIN; BLUE COPPER SITE; ABSORPTION-SPECTROSCOPY; ACETYL-COA; COORDINATION ENVIRONMENT; KINETIC CHARACTERIZATION; BIOINORGANIC SYSTEMS; ALPHA-METALLOSUBUNIT AB Carbon monoxide dehydrogenase from Clostridium thermoaceticum (Ct-CODH) is a nickel-containing enzyme that catalyzes acetyl-CoA synthesis and CO oxidation at two separate Ni sites, the A-cluster and C-cluster, respectively. Carbon monoxide dehydrogenase from Rhodospirillum rubrum (Rr-CODH) contains only a C-type cluster and catalyzes only Ca oxidation. We have used L-edge X-ray absorption spectroscopy to study the Ni electronic structure of these two enzymes. The spectra indicate that most of the Ni in as-isolated Ct-CODH is low-spin Ni(II). Upon CO treatment, a fraction of the nickel is converted either to high-spin Ni(II) and/or to Ni(I). Ni in dithionite-reduced Rr-CODH also exhibits a clear low spin Ni(II) component, again mixed with either high-spin Ni(II) or Ni(I). The spectrum of Rr-CODH shifts to higher energy upon indigo carmine oxidation, suggesting either that most of the high-spin Ni(II) is converted to low-spin Ni(II) and/or that some Ni is oxidized between these two forms; These results are;discussed and compared with recent L-edge spectra for the Ni site in hydrogenase. C1 Univ Calif Davis, Dept Appl Sci, Davis, CA 95616 USA. Univ Nebraska, Dept Biochem, Lincoln, NE 68583 USA. Univ Wisconsin, Dept Biochem, Madison, WI 53706 USA. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Cramer, SP (reprint author), Univ Calif Davis, Dept Appl Sci, Davis, CA 95616 USA. NR 78 TC 41 Z9 41 U1 3 U2 11 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 NOV 1 PY 2000 VL 122 IS 43 BP 10553 EP 10560 DI 10.1021/ja0009469 PG 8 WC Chemistry, Multidisciplinary SC Chemistry GA 371XR UT WOS:000165205000007 ER PT J AU Chen, Z Ward, R Tian, Y Baldelli, S Opdahl, A Shen, YR Somorjai, GA AF Chen, Z Ward, R Tian, Y Baldelli, S Opdahl, A Shen, YR Somorjai, GA TI Detection of hydrophobic end groups on polymer surfaces by sum-frequency generation vibrational spectroscopy SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID PROTEIN ADSORPTION; LATTICE MODEL; CHAIN-ENDS; INTERFACES; TENSION; ORIENTATION; SEGREGATION; DENSITY; BLENDS; MELT AB We report the successful application of SFG to detect segregation of end groups on polymer surfaces. Two groups of polymer samples are studied: one is polyurethane with different surface-modified end groups, the other is poly(ethylene glycol) (PEG) with different end groups. For each group of polymers, both hydrophobic and hydrophilic end groups are chosen. With the surface sensitivity of SFG, we have found that hydrophobic end groups [e.g., methoxy on PEG or poly(dimethylsiloxane) (PDMS) on polyurethane] tend to segregate to the polymer surface in ail. However, the hydrophilic end groups (e.g., hydroxyl group on PEG or PEG on polyurethane) remain in the bulk so that the surfaces that are exposed to air are covered by the polymer backbones. Although contact-angle measurements and XPS results can demonstrate that polymer surfaces indeed have been modified by different end groups, only SFG can show the surface structure at the molecular level. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. Polymer Technol Grp Inc, Berkeley, CA 94710 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RP Somorjai, GA (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Chen, Zhan/G-8312-2016 OI Chen, Zhan/0000-0001-8687-8348 NR 34 TC 84 Z9 88 U1 2 U2 37 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 NOV 1 PY 2000 VL 122 IS 43 BP 10615 EP 10620 DI 10.1021/ja000808j PG 6 WC Chemistry, Multidisciplinary SC Chemistry GA 371XR UT WOS:000165205000014 ER PT J AU Song, WG Haw, JF Nicholas, JB Heneghan, CS AF Song, WG Haw, JF Nicholas, JB Heneghan, CS TI Methylbenzenes are the organic reaction centers for methanol-to-olefin catalysis on HSAPO-34 SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID HYDROCARBON FORMATION; REACTION-MECHANISM; CO-REACTION; SAPO-34; CONVERSION; ZEOLITE C1 Univ So Calif, Loker Hydrocarbon Res Inst, Los Angeles, CA 90089 USA. Univ So Calif, Dept Chem, Los Angeles, CA 90089 USA. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Haw, JF (reprint author), Univ So Calif, Loker Hydrocarbon Res Inst, Los Angeles, CA 90089 USA. RI Song, Weiguo/D-6041-2016 OI Song, Weiguo/0000-0001-5390-6787 NR 11 TC 226 Z9 238 U1 16 U2 78 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 NOV 1 PY 2000 VL 122 IS 43 BP 10726 EP 10727 DI 10.1021/ja002195g PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 371XR UT WOS:000165205000036 ER PT J AU Van Berkel, GJ AF Van Berkel, GJ TI Insights into analyte electrolysis in an electrospray emitter from chronopotentiometry experiments and mass transport calculations SO JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY LA English DT Article ID ELECTROCHEMICAL OXIDATION; ION-SOURCE; GAS-PHASE; IONIZATION; SPECTROMETRY; METALLOCENES; DERIVATIVES; INTERFACE; INHERENT; CELL AB Insights into the electrolysis of analytes at the electrode surface of an electrospray (ES) emitter capillary are realized through an examination of the results from off-line chronopotentiometry experiments and from mass transport calculations for flow through tubular electrodes. The expected magnitudes and trends in the interfacial potential in an ES emitter under different solution conditions and current densities, using different metal electrodes, are revealed by the chronopotentiometry data. The mass transport calculations reveal the electrode area required for complete analyte electrolysis at a given volumetric flow rate. On the basis of these two pieces of information, the design of ES emitters that may maximize and those that may minimize analyte electrolysis during ES mass spectrometry are discussed. (C) 2000 American Society for Mass Spectrometry. C1 Oak Ridge Natl Lab, Chem & Analyt Sci Div, Oak Ridge, TN 37831 USA. RP Van Berkel, GJ (reprint author), Oak Ridge Natl Lab, Chem & Analyt Sci Div, Oak Ridge, TN 37831 USA. NR 30 TC 41 Z9 41 U1 1 U2 8 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 1044-0305 J9 J AM SOC MASS SPECTR JI J. Am. Soc. Mass Spectrom. PD NOV PY 2000 VL 11 IS 11 BP 951 EP 960 PG 10 WC Chemistry, Analytical; Chemistry, Physical; Spectroscopy SC Chemistry; Spectroscopy GA 367WR UT WOS:000090084900004 ER PT J AU Gover, RKB Kanno, R Mitchell, BJ Yonemura, M Kawamoto, Y AF Gover, RKB Kanno, R Mitchell, BJ Yonemura, M Kawamoto, Y TI Effects of sintering temperature on the structure of the layered phase Li-x(Ni0.8Co0.2)O-2 SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID RECHARGEABLE LITHIUM BATTERIES; LINI1-YCOYO2 SOLID-SOLUTION; NEUTRON-DIFFRACTION; ELECTRODE MATERIALS; LI-7 NMR; OXIDE; DEINTERCALATION; PERFORMANCE AB The structure of the layered phase Li-x(Ni0.8Co0.2)O-2 was studied extensively by powder X-ray and neutron diffraction, and the relationships between the sintering temperature, structure, and electrochemical properties were determined. Samples in this study were prepared with a sintering time of 48 h at 600-750 degreesC, and all indicated the presence of Ni on the Li site, based on structural analysis by the Rietveld method. The sample with the lowest level of Ni (similar to2.0%) on the Li site was prepared at 725 degreesC. Structural analysis also indicated that the occupancy of the Ni/Co layer varied as a function of the sintering temperature, but as the sintering temperature was increased, the deviation from the expected value decreased. Electrochemical measurements were carried out on these samples, and the best sample in terms of electrochemical properties was that prepared at 725 degreesC. This sample exhibited initial discharge capacities of similar to 190 mAh/g. All other samples delivered lower capacities, behavior which correlates with the degree of Li site disordering. These results clearly show the role of 3a site disorder on the electrochemical properties of these materials. However, we have not determined the role of the Ni/Co site, in particular, the disorder on electrochemical properties. (C) 2000 The Electrochemical Society. S0013-4651(00)05-010-2. All rights reserved. C1 Kobe Univ, Fac Sci, Dept Chem, Kobe, Hyogo 6570023, Japan. Argonne Natl Lab, Intense Pulsed Neutron Source, Argonne, IL 60439 USA. RP Gover, RKB (reprint author), Kobe Univ, Fac Sci, Dept Chem, Kobe, Hyogo 6570023, Japan. EM kanno@kobe-u.ac.jp NR 32 TC 39 Z9 39 U1 0 U2 7 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 65 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 0013-4651 EI 1945-7111 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD NOV PY 2000 VL 147 IS 11 BP 4045 EP 4051 DI 10.1149/1.1394016 PG 7 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 367GQ UT WOS:000090053700011 ER PT J AU Besmann, TM Klett, JW Henry, JJ Lara-Curzio, E AF Besmann, TM Klett, JW Henry, JJ Lara-Curzio, E TI Carbon/carbon composite bipolar plate for proton exchange membrane fuel cells SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article AB Carbon/carbon-composite bipolar plates for proton exchange membrane fuel cells (PEMFC) have been fabricated by slurry molding a chopped-fiber preform followed by sealing with chemically vapor-infiltrated carbon. The resulting component is hermetic with respect to through-thickness leakage and has a high electronic conductivity (200-300 S/cm) as a result of the deposited graphitic carbon. The material has a low density (0.96 g/cm(3)) due to retained porosity resulting in a low-weight component. Biaxial flexure strength was measured to be 175 +/- 26 MPa. Cell testing of a 100 cm(2) active area, single-sided plate indicated very low cell resistance and high efficiency, but with a somewhat steep drop-off in voltage with current at high values. Corrosion testing indicated minimal corrosion in fuel cell environments. (C) 2000 The Electrochemical Society. S0013-4651(99)09-074-6. All rights reserved. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37830 USA. RP Besmann, TM (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37830 USA. EM besmanntm@ornl.gov RI 李, 应辉/A-7739-2011; Klett, James/E-6860-2017 OI Klett, James/0000-0002-2553-9649 NR 9 TC 89 Z9 95 U1 1 U2 19 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 65 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD NOV PY 2000 VL 147 IS 11 BP 4083 EP 4086 DI 10.1149/1.1394023 PG 4 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 367GQ UT WOS:000090053700018 ER PT J AU Salmon, CP Knize, MG Panteleakos, DN Wu, RW Nelson, DO Felton, JS AF Salmon, CP Knize, MG Panteleakos, DN Wu, RW Nelson, DO Felton, JS TI Minimization of heterocyclic amines and thermal inactivation of Escherichia coli in fried ground beef SO JOURNAL OF THE NATIONAL CANCER INSTITUTE LA English DT Article ID AROMATIC-AMINES; MEAT-PRODUCTS; WELL-DONE; COOKED FOODS; RED MEAT; TEMPERATURE; O157-H7; HEAT; RISK; HYDROCARBONS AB Background: Heterocyclic amine carcinogens are formed during the cooking of a number of foods, especially well-done meats. Lower temperatures and shorter cooking times can minimize the formation of these carcinogens, yet a major food safety concern is that pathogens in the meat must be thermally inactivated. This study investigated cooking techniques that minimize heterocyclic amine formation while simultaneously destroying contaminating bacteria. Methods: Ground beef patties were inoculated with Escherichia coli K12 bacteria and fried to internal temperatures ranging from 35 degreesC to 70 degreesC in a skillet preheated to 160 degreesC, 180 degreesC, or 200 degreesC. Each patty was then analyzed for four common heterocyclic amines and for surviving bacteria. Additionally, the frequency of turning of the beef patty during cooking was varied (a single turn or multiple turns), length of time required for each patty to reach 70 degreesC was recorded, and heterocyclic amine levels were determined. An additional pan temperature of 250 degreesC was tested for its effect on heterocyclic amine formation but not on bacterial killing. Statistical tests were two-sided. Results: Colony-forming bacteria were reduced by five orders of magnitude at internal temperatures greater than 60 degreesC, regardless of cooking method, and were completely inactivated at 70 degreesC, For patties turned just once, heterocyclic amine levels increased as the cooking temperatures increased. However, levels of heterocyclic amines were statistically significantly lower with turning every minute. For each pan temperature, patties reached 70 degreesC internal temperature sooner when they were turned every minute than when they were turned just once during cooking. Conclusion: Lowering the pan temperature and turning the patties frequently can greatly reduce the formation of heterocyclic amines and can simultaneously achieve bacterial inactivation with little or no increase in cooking time, ensuring a product that is safe for human consumption. C1 Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94550 USA. RP Knize, MG (reprint author), Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, L-452,POB 808, Livermore, CA 94550 USA. FU NCI NIH HHS [CA55861] NR 35 TC 32 Z9 33 U1 1 U2 3 PU NATL CANCER INSTITUTE PI BETHESDA PA 9030 OLD GEORGETOWN RD, BETHESDA, MD 20814 USA SN 0027-8874 J9 J NATL CANCER I JI J. Natl. Cancer Inst. PD NOV 1 PY 2000 VL 92 IS 21 BP 1773 EP 1778 DI 10.1093/jnci/92.21.1773 PG 6 WC Oncology SC Oncology GA 368HC UT WOS:000090110800014 PM 11058620 ER PT J AU Coutts, TJ Young, DL Li, X Mulligan, WP Wu, X AF Coutts, TJ Young, DL Li, X Mulligan, WP Wu, X TI Search for improved transparent conducting oxides: A fundamental investigation of CdO, Cd2SnO4, and Zn2SnO4 SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Review ID THIN-FILMS; OPTICAL-PROPERTIES; CADMIUM STANNATE; ELECTRICAL-PROPERTIES; SPECTROSCOPY; MECHANISMS; MOSSBAUER; COATINGS; IN2O3 AB The bulk of developmental work on transparent conducting oxides (TCOs) has been somewhat empirical. This statement applies both to more familiar materials such as indium tin oxide (ITO) and to less-well-known materials that have emerged in recent years. In this at-tide, we place a greater emphasis on more fundamental research. Our eventual goal is to gain a thorough understanding of these materials, their potential for further improvement, whether or not they suggest new and potentially superior materials, and the way their properties are influenced by structural and other issues. We also hope to provide guidelines to other researchers working in this area. We have investigated films of cadmium oxide (CdO), cadmium stannate (Cd2SnO4 or CTO), and zinc stannate [Zn2SnO4 (ZTO)]. The CdO was prepared by chemical-vapor deposition, whereas the stannates were prepared by rf sputtering. Tn both cases, Coming 7059 glass substrates were used. However, some depositions were also made onto tin oxide, which had a profound effect on the nucleation of CdO, in particular. It is well known that a high free-carrier mobility is essential for a TCO with near-ideal electro-optical properties. Increasing the free-carrier concentration also increases the free-carrier absorbance but a higher mobility reduces it. We have achieved free-electron mobilities in CdO (E(g)similar to2.4 eV) of greater than 200 cm(2) V-1 s(-1), of almost 80 cm(2) V-1 s(-1) in CTO (E(g)similar to3.1 eV), but of only 10-15 cm(2) V-1 s(-1) in ZTO (E(g)similar to3.6 eV). We have characterized these materials, and will show key data, using techniques as diverse as the Nernst-Ettingshausen effect; Mossbauer, Raman, optical, and near-infrared spectroscopies; atomic-force and high-resolution electron microscopy; and x-ray diffraction. These measurements have enabled us to determine the effective mass of the free carriers and their relaxation time, the probable distributions of cations between octahedral and tetrahedral sites, the role of the deposition parameters on the carrier concentrations, and the nature of the dominant scattering mechanisms. We also consider issues relating to toxicity of cadmium and to reserves of indium. Both are of great significance to prospective large-volume manufacturers of TCO films and must be taken into account by researchers. (C) 2000 American Vacuum Society. [S0734-2101(00)00206-2]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. Sun Power Corp, Sunnyvale, CA 94086 USA. RP Coutts, TJ (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. NR 47 TC 237 Z9 240 U1 11 U2 130 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD NOV-DEC PY 2000 VL 18 IS 6 BP 2646 EP 2660 DI 10.1116/1.1290371 PG 15 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 375FH UT WOS:000165388500002 ER PT J AU Tu, VJ Jeong, JY Schutze, A Babayan, SE Ding, G Selwyn, GS Hicks, RF AF Tu, VJ Jeong, JY Schutze, A Babayan, SE Ding, G Selwyn, GS Hicks, RF TI Tantalum etching with a nonthermal atmospheric-pressure plasma SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article ID SPUTTER DEPOSITED TANTALUM; JET; FILMS; SILICON AB Tantalum was etched in a downstream, atmospheric-pressure plasma. In this process, etching occurred without significant ion bombardment. An etching rate of 6.0+/-0.5 mum/min was achieved using 14.8 Torr oxygen, 22.4 Torr carbon tetrafluoride, 720+/-5 Torr helium, 685 W radio frequency power at 13.56 MHz, and a film temperature of 300 degreesC. The etching rate increased with the applied power, carbon tetrafluoride pressure, oxygen pressure, and residence time of the gas between the electrodes, indicating that the surface reaction depends on the density of reactive fluorine species generated in the plasma. X-ray photoemission spectroscopy revealed that the etched surface was covered with tantalum fluoride and to a lesser extent, tantalum oxide. Based on these observations, a mechanism for tantalum etching is proposed which involves the reaction between fluorine atoms and the adsorbed tantalum fluoride. (C) 2000 American Vacuum Society. [S0734-2101(00)01806-6]. C1 Univ Calif Los Angeles, Dept Chem Engn, Los Angeles, CA 90095 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Hicks, RF (reprint author), Univ Calif Los Angeles, Dept Chem Engn, Los Angeles, CA 90095 USA. NR 32 TC 42 Z9 43 U1 3 U2 10 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD NOV-DEC PY 2000 VL 18 IS 6 BP 2799 EP 2805 DI 10.1116/1.1310652 PG 7 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 375FH UT WOS:000165388500022 ER PT J AU Berry, L Maynard, H Miller, P Moore, T Pendley, M Resta, V Sparks, D Yang, QY AF Berry, L Maynard, H Miller, P Moore, T Pendley, M Resta, V Sparks, D Yang, QY TI Control of the radio-frequency wave form at the chuck of an industrial oxide-each reactor SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article ID PLASMA REACTOR; CHF3 AB Radio frequency (rf) power is commonly applied to the chuck of a high-density plasma reactor in order to extract ions and to control the energy of the ions used for the fabrication of microelectronic devices. In many cases, the temporal shape of the rf wave form largely determines the shape of the spectrum of those extracted ions, thereby strongly affecting feature evolution. Using auxiliary rf circuits, we successfully made major changes to the rf-potential wave form at the chuck of an Applied Materials 5300 HDP Omega reactor without affecting the normal functioning of the reactor's control systems. This work established the practical feasibility of techniques for modifying the ion energy distribution functions of industrial reactors. (C) 2000 American Vacuum Society. [S0734-2101(00)05406-3]. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. SEMATECH, Austin, TX 78741 USA. RP Berry, L (reprint author), Oak Ridge Natl Lab, POB 2009, Oak Ridge, TN 37831 USA. NR 11 TC 10 Z9 10 U1 1 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD NOV-DEC PY 2000 VL 18 IS 6 BP 2806 EP 2814 DI 10.1116/1.1319819 PG 9 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 375FH UT WOS:000165388500023 ER PT J AU Young, DL Coutts, TJ Kaydanov, VI Gilmore, AS Mulligan, WP AF Young, DL Coutts, TJ Kaydanov, VI Gilmore, AS Mulligan, WP TI Direct measurement of density-of-states effective mass and scattering parameter in transparent conducting oxides using second-order transport phenomena SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 46th International Symposium of the American-Vacuum-Society CY OCT 25-29, 1999 CL SEATTLE, WASHINGTON SP Amer Vacuum Soc ID ZNO; FILMS AB The Boltzmann transport equation can be solved to give analytical solutions to the resistivity, Hall, Seebeck, and Nernst coefficients. These solutions may be solved simultaneously to give the density-of-states effective mass band, and a scattering parameter that is related to a relaxation time and the Fermi energy. The Nernst coefficient is essential for determining the scattering parameter and, thereby, the effective scattering mechanism(s). We constructed equipment to measure these four transport coefficients simultaneously over a temperature range of 30-350 K for thin, semiconducting films deposited on insulating substrates. We measured these coefficients for rf magnetron-sputtered zinc oxide, both doped and undoped, with aluminum with carrier concentrations in the range of 1x10(19)-5 X 10(20) cm(-3). The (m(d)*) was not constant over this carrier concentration range: varying from 0.3 to 0.48 m(e), leading us to conclude that zinc oxide has a nonparabolic conduction band. Conductivity effective mass values for zinc oxide matched our m(d)* values, revealing a single valley, nearly spherical, constant energy surface for zinc oxide. The measured scattering parameter changed from close to zero to 1.5 as the carrier concentrations increased. The scattering parameter, Seebeck coefficient, and mobility versus temperature data support neutral impurity scattering in the undoped material and ionized impurity scattering in the Al-doped ZnO. The transport theory also allows an extrapolation for an m(d)* value at the bottom of the conduction band, which was found to be 0.27 m(e). (C) 2000 American Vacuum Society. [S0734-2101(00)00106-8]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. Colorado Sch Mines, Golden, CO 80401 USA. Sunpower Inc, Sunnyvale, CA USA. RP Young, DL (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. NR 22 TC 74 Z9 75 U1 1 U2 31 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD NOV-DEC PY 2000 VL 18 IS 6 BP 2978 EP 2985 DI 10.1116/1.1290372 PG 8 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 375FH UT WOS:000165388500049 ER PT J AU Tangyunyong, P Benson, D Cole, EI AF Tangyunyong, P Benson, D Cole, EI TI Thermal modeling of a polysilicon-metal test structure used for thermally induced voltage alteration characterization SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article AB Thermal modeling and simulations were used to analyze the thermal profiles of a polysilicon-metal test structure generated by localized heating with an infrared laser. Localized laser heating is the basis of a new failure analysis technique, thermally induced voltage alteration (TIVA), that can identify shorted interconnects in integrated circuits. The modeling results show that variations in thermal profiles of the test structure measured by the TIVA technique are due mainly to preferential laser absorption in various locations in the test structure. Differences in oxide thickness also affect the local heat conduction and temperature distribution. Modeling results also show that local variation in heat conduction is less important than the absorbed laser power in determining the local temperatures since our test structure has feature sizes that are small compared to the length over which the heat spreads. (C) 2000 American Vacuum Society. [S0734-211X(00)18606-8]. C1 Sandia Natl Labs, Integrated Circuit Failure Anal Dept, Albuquerque, NM 87185 USA. Sandia Natl Labs, Adv Packaging Dept, Albuquerque, NM 87185 USA. RP Tangyunyong, P (reprint author), Sandia Natl Labs, Integrated Circuit Failure Anal Dept, POB 5800, Albuquerque, NM 87185 USA. NR 7 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD NOV-DEC PY 2000 VL 18 IS 6 BP 2820 EP 2825 DI 10.1116/1.1327297 PG 6 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 384HB UT WOS:000165935800040 ER PT J AU Goldberg, KA Naulleau, P Batson, P Denham, P Anderson, EH Chapman, H Bokor, J AF Goldberg, KA Naulleau, P Batson, P Denham, P Anderson, EH Chapman, H Bokor, J TI Extreme ultraviolet alignment and testing of a four-mirror ring field extreme ultraviolet optical system SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 44th International Conference on Electron Ion and Photon Beam Technology and Nanofabrication (EIPBN) CY MAY 30-JUN 02, 2000 CL RANCHO MIRAGE, CALIFORNIA SP Amer Vacuum Soc, IEEE Electron Devices Soc, Opt Soc Amer ID POINT-DIFFRACTION INTERFEROMETER; LITHOGRAPHY; EUV; COATINGS; ACCURACY; TOOL AB Extreme ultraviolet (EUV) interferometry has been used to characterize and align a recently fabricated, 4X reduction, four-minor, aspheric optical system designed for EUV lithography. This system is called the Engineering Test Stand Set-1 Optic. An EUV phase-shifting point diffraction interferometer constructed on an undulator beamline at the Advanced Light Source was used to perform high-accuracy wavefront measurements during several alignment iterations. For each iteration, the alignment algorithm used 35 wavefront measurements recorded across the 26-mm-wide image-side ring field. Adjustments were made to systematically reduce the root mean square wavefront error magnitude to approximately I nm, bringing the system to nearly diffraction-limited performance. (C) 2000 American Vacuum Society. [q0734-211X(00)05106-4]. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Berkeley, Dept EECS, Berkeley, CA 94720 USA. RP Goldberg, KA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. RI Chapman, Henry/G-2153-2010; Bokor, Jeffrey/A-2683-2011 OI Chapman, Henry/0000-0002-4655-1743; NR 20 TC 26 Z9 26 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD NOV-DEC PY 2000 VL 18 IS 6 BP 2911 EP 2915 DI 10.1116/1.1319703 PG 5 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 384HB UT WOS:000165935800056 ER PT J AU Yi, M Jeong, S Rekawa, S Bokor, J AF Yi, M Jeong, S Rekawa, S Bokor, J TI Characterization of extreme ultraviolet lithography mask defects from extreme ultraviolet far-field scattering patterns SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 44th International Conference on Electron Ion and Photon Beam Technology and Nanofabrication (EIPBN) CY MAY 30-JUN 02, 2000 CL RANCHO MIRAGE, CALIFORNIA SP Amer Vacuum Soc, IEEE Electron Devices Soc, Opt Soc Amer ID BLANK DEFECTS AB We present far-field scattering patterns from programmed phase and opaque defects on extreme ultraviolet lithography mask blanks. Distinct diffraction fringes were observed for both defect types, with fringe spacing dependent on the defect size. Phase defects and opaque defects were found to show clear differences in scattering properties that can be utilized to classify defects. (C) 2000 American Vacuum Society. [S0734-211X(00)09706-7]. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept EECS, Berkeley, CA 94720 USA. RP Yi, M (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Ctr Xray Opt, 1 Cyclotron Rd,MS 2-400, Berkeley, CA 94720 USA. RI Bokor, Jeffrey/A-2683-2011 NR 8 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD NOV-DEC PY 2000 VL 18 IS 6 BP 2930 EP 2934 DI 10.1116/1.1319843 PG 5 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 384HB UT WOS:000165935800060 ER PT J AU Lee, SH Bokor, J Naulleau, P Jeong, ST Goldberg, KA AF Lee, SH Bokor, J Naulleau, P Jeong, ST Goldberg, KA TI Extreme ultraviolet holographic microscopy and its application to extreme ultraviolet mask-blank defect characterization SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 44th International Conference on Electron Ion and Photon Beam Technology and Nanofabrication (EIPBN) CY MAY 30-JUN 02, 2000 CL RANCHO MIRAGE, CALIFORNIA SP Amer Vacuum Soc, IEEE Electron Devices Soc, Opt Soc Amer AB 100-nm-resolution at-wavelength holographic microscopy of aerial images produced by extreme ultraviolet (EUV) lithographic optics has recently been demonstrated. It provides a simple and compact method allowing image monitoring without printing in photoresist. Here, the concept of holographic microscopy is extended to the characterizations of defects on EUV multilayer mask blanks. As a proof of principle, defect characterization using the holographic microscope is demonstrated with programmed defects in transmission masks. Amplitude defects as small as 100 nm have been successfully characterized. Extension of this technique to the more relevant reflection mask configuration is also discussed. (C) 2000 American Vacuum Society. [S0734-211X(00)02506-3]. C1 Univ Calif Berkeley, Dept Elect Engn & Comp Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. RP Lee, SH (reprint author), Univ Calif Berkeley, Dept Elect Engn & Comp Sci, Berkeley, CA 94720 USA. RI Bokor, Jeffrey/A-2683-2011 NR 7 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD NOV-DEC PY 2000 VL 18 IS 6 BP 2935 EP 2938 DI 10.1116/1.1314382 PG 4 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 384HB UT WOS:000165935800061 ER PT J AU Naulieau, PP Goldberg, KA Bokor, J AF Naulieau, PP Goldberg, KA Bokor, J TI Extreme ultraviolet carrier-frequency shearing interferometry of a lithographic four-mirror optical system SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 44th International Conference on Electron Ion and Photon Beam Technology and Nanofabrication (EIPBN) CY MAY 30-JUN 02, 2000 CL RANCHO MIRAGE, CALIFORNIA SP Amer Vacuum Soc, IEEE Electron Devices Soc, Opt Soc Amer ID POINT-DIFFRACTION INTERFEROMETER; IMAGING-SYSTEM; RADIATION AB The phase-shifting point diffraction interferometer (PS/PDI) has recently been developed to address the problem of at-wavelength metrology of extreme ultraviolet (EUV) optical systems. Although extremely accurate, the fact that the PS/PDI is limited to use with coherent EUV sources, such as undulator radiation, is a drawback for its widespread use. An alternative to the PS/PDI, with relaxed coherence requirements, is lateral shearing interferometry (LSI). Here we describe various LSI implementations and demonstrate the use of a cross-grating, carrier-frequency configuration to characterize a large-field 4X-reduction EUV lithography optic. The results obtained are directly compared with PS/PDI measurements. (C) 2000 American Vacuum Society. [S0734-211X(00)12806-9]. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Elect Engn & Comp Sci, Berkeley, CA 94720 USA. RP Naulieau, PP (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. RI Bokor, Jeffrey/A-2683-2011 NR 21 TC 47 Z9 50 U1 0 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD NOV-DEC PY 2000 VL 18 IS 6 BP 2939 EP 2943 DI 10.1116/1.1321290 PG 5 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 384HB UT WOS:000165935800062 ER PT J AU Cardinale, GF Ray-Chaudhuri, AK Fisher, A Mangat, PSJ Wasson, J Mirkarimi, PB Gullikson, E AF Cardinale, GF Ray-Chaudhuri, AK Fisher, A Mangat, PSJ Wasson, J Mirkarimi, PB Gullikson, E TI Effects of smoothing on defect printability at extreme ultraviolet wavelengths SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 44th International Conference on Electron Ion and Photon Beam Technology and Nanofabrication (EIPBN) CY MAY 30-JUN 02, 2000 CL RANCHO MIRAGE, CALIFORNIA SP Amer Vacuum Soc, IEEE Electron Devices Soc, Opt Soc Amer ID LITHOGRAPHY AB Improvements in mask blank yield by the reduction in defects dramatically reduces the reticle cost of any lithography. Extreme ultraviolet lithography (EUVL) masks typically consist of a substrate coated with reflective multilayer (ML) materials (e.g., Mo and Si), followed by a sacrificial or "repair" layer (e.g., SiO2 and top absorber layer material (e.g., Cr or TaSiNx). Defects of the following two types exist: substrate and absorber defects. Substrate defects are generally below the absorber and buffer layers, i.e., at the substrate-ML interface or within the ML stack, whereas the absorber defects are located at the absorber layer. In addition, the printability of substrate-type defects may be reduced by coating the defects with a planarizing or smoothing layer. In this work, we discuss simulation and experimental results that compare the printability of programmed defect reticles with and without smoothing layers covering the programmed defect. We propose several criteria for smoothing layer specifications that are necessary to mitigate a size range of defects for an EUV imaging system. (C) 2000 American Vacuum Society. [S0734-211X(00)16706-X]. C1 Sandia Natl Labs, Livermore, CA 94550 USA. DigitalDNA TM Labs, APRDL, Phoenix, AZ 85284 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Lawrence Berkeley Natl Lab, Berkeley, CA USA. RP Cardinale, GF (reprint author), Sandia Natl Labs, Livermore, CA 94550 USA. NR 15 TC 9 Z9 9 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD NOV-DEC PY 2000 VL 18 IS 6 BP 2944 EP 2949 DI 10.1116/1.1324637 PG 6 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 384HB UT WOS:000165935800063 ER PT J AU Anderson, EH Olynick, DL Harteneck, B Veklerov, E Denbeaux, G Chao, WL Lucero, A Johnson, L Attwood, D AF Anderson, EH Olynick, DL Harteneck, B Veklerov, E Denbeaux, G Chao, WL Lucero, A Johnson, L Attwood, D TI Nanofabrication and diffractive optics for high-resolution x-ray applications SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 44th International Conference on Electron Ion and Photon Beam Technology and Nanofabrication (EIPBN) CY MAY 30-JUN 02, 2000 CL RANCHO MIRAGE, CALIFORNIA SP Amer Vacuum Soc, IEEE Electron Devices Soc, Opt Soc Amer ID ELECTRON-BEAM LITHOGRAPHY; RESIST AB Short wavelength x-ray radiation microscopy is well suited for a number of material and life science studies. The x-ray microscope (XM1) at the Advanced Light Source Synchrotron in Berkeley, California uses two diffractive Fresnel zone plate lenses. The first is a large condenser lens, which collects soft x-ray radiation from a bending magnet, focuses it, and serves as a linear monochromator. The second is the objective zone plate lens, which magnifies the image of the specimen onto a high-efficiency charge coupled device detector. The objective lens determines the numerical aperture and ultimate resolution. New objective lens zone plates with a minimum linewidth of 25 nm and excellent linewidth control have been fabricated using Berkeley Lab's 100 keV Nanowriter electron beam lithography tool, a calixarene high-resolution negative resist, and gold electroplating. Although the condenser zone plate is less critical to the resolution of the instrument, its efficiency determines the flux on the sample and ultimately the exposure time. A new condenser zone plate was fabricated and has a 9 mm diameter, 44 000 zones, and a minimum zone width of 54 nm (optimally the condenser and objective should have the same zone width). It is also fabricated with the Nanowriter at 100 keV using poly(methylmethacrylate) resist and nickel electroplating. The phase shift through the nickel absorber material enhances the diffraction efficiency over an amplitude only zone plate. To evaluate the microscope's performance transmission test patterns have been made and imaged. Lineout data show modulation for 30 nm lines and 60 (1:2) spaces to be almost 100%. These new diffractive optical elements represent a significant advancement in the field of high-resolution soft x-ray microscopy. Diffractive optical elements have been used to measure the wave front error of an extreme ultraviolet projection optical system. The reference wave is generated by the spherical wave generated by diffraction from a small freestanding pinhole. (C) 2000 American Vacuum Society. [S0734-211X(00)11106-0]. C1 EO Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Anderson, EH (reprint author), EO Lawrence Berkeley Natl Lab, Mail Stop 2-400,1 Cyclotron Rd, Berkeley, CA 94720 USA. RI Johnson, Lewis/G-1519-2013 NR 14 TC 94 Z9 97 U1 5 U2 20 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD NOV-DEC PY 2000 VL 18 IS 6 BP 2970 EP 2975 DI 10.1116/1.1321282 PG 6 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 384HB UT WOS:000165935800068 ER PT J AU Xiu, K Gibson, JM AF Xiu, K Gibson, JM TI Correction of the field curvature in SCALPEL projection systems SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 44th International Conference on Electron Ion and Photon Beam Technology and Nanofabrication (EIPBN) CY MAY 30-JUN 02, 2000 CL RANCHO MIRAGE, CALIFORNIA SP Amer Vacuum Soc, IEEE Electron Devices Soc, Opt Soc Amer ID ELECTRON AB The field curvature and axial chromatic aberration, 2 of 13 aberrations in an electron optical system, make the major contributions to the image blur of a SCALPEL projector. We first give a simple yet quantitative evaluation of the point spread function from the field curvature and chromatic aberration and show the merit of keeping a comparatively low field curvature. Then we describe two ways to reduce the field curvature in an electron projection system. One is to use an immersion magnetic doublet with a constant field along most of the optical column with opposite signs at two ends which are connected by a sharp field transition region. The other way is to use space charge foils. By putting a space charge foil with homogeneously distributed space charge density on either the object or image plane, we show the field curvature can be eliminated in principle without affecting any other aberrations. (C) 2000 American Vacuum Society. [S0734-211X(00)12506-5]. C1 Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Xiu, K (reprint author), Univ Illinois, Dept Phys, 1110 W Green St, Urbana, IL 61801 USA. RI Gibson, Murray/E-5855-2013 OI Gibson, Murray/0000-0002-0807-6224 NR 7 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD NOV-DEC PY 2000 VL 18 IS 6 BP 3067 EP 3071 DI 10.1116/1.1321287 PG 5 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 384HB UT WOS:000165935800086 ER PT J AU Scott, KL King, TJ Lieberman, MA Leung, KN AF Scott, KL King, TJ Lieberman, MA Leung, KN TI Pattern generators and microcolumns far ion beam lithography SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 44th International Conference on Electron Ion and Photon Beam Technology and Nanofabrication (EIPBN) CY MAY 30-JUN 02, 2000 CL RANCHO MIRAGE, CALIFORNIA SP Amer Vacuum Soc, IEEE Electron Devices Soc, Opt Soc Amer AB A self-aligned microfabrication process has been developed for micron-sized extraction systems, which can be used for pattern generators or microcolumns in ion beam lithography. The extraction of ions from a plasma source through micron-sized apertures is shown not to follow traditional design rules, and the governing equations of interest for meeting design parameters are presented. First order focal properties of the pattern generator and microcolumn are described using Davisson and Calbick's derivation [C. J. Davisson and C, J. Calbick, Phys. Rev. 38, 558 (1931); 42, 580 (1932)] for an aperture lens. A second order refinement of the focal properties is characterized and explained with computer simulations using MEBS(C). (C) 2000 American Vacuum Society. [S0734-211X(00)02706-2]. C1 Univ Calif Berkeley, Dept Elect Engn & Comp Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Scott, KL (reprint author), Univ Calif Berkeley, Dept Elect Engn & Comp Sci, Berkeley, CA 94720 USA. NR 16 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD NOV-DEC PY 2000 VL 18 IS 6 BP 3172 EP 3176 DI 10.1116/1.1314384 PG 5 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 384HB UT WOS:000165935800105 ER PT J AU Dentinger, PM AF Dentinger, PM TI Outgassing of photoresist materials at extreme ultraviolet wavelengths SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 44th International Conference on Electron Ion and Photon Beam Technology and Nanofabrication (EIPBN) CY MAY 30-JUN 02, 2000 CL RANCHO MIRAGE, CALIFORNIA SP Amer Vacuum Soc, IEEE Electron Devices Soc, Opt Soc Amer ID CHEMICALLY AMPLIFIED RESISTS AB Outgassing of photoresist materials is a concern for all advanced lithographies. To address this concern, outgassing of photoresist materials exposed at extreme ultraviolet (EUV) wavelengths was studied with a quartz crystal microbalance (QCM) and mass spectrometry and was quantified using the QCM. Mass spectrometry of poly(methylmethacrylate) at 13.4 nm indicated large quantities of hydrogen formed by exposure at EUV wavelengths. QCM studies showed that pure acrylic materials are particularly susceptible to outgassing while pure styrenic materials outgas approximately two orders of magnitude less mass per unit dose. Random copolymers of acrylics and hydroxystyrene, such as found in common 248 nm lithography materials were disproportionately low outgassers. The phenolic moieties randomly introduced into the backbone of acrylics reduced the outgassing by approximately an order of magnitude below what was expected from the pure polymers. It is thought that radical scavenging by phenolic moieties stabilize the acrylic monomers. In addition, judicious selection of the photoacid generator (PAG) is important. It is shown that some PAGs, even at concentrations of 3.8 wt % produce 4 times more volatile mass than the resin itself. The residual solvent left in the film after the postapply bake (PAB) can contribute and even dominate outgassing if the PAB is too low. For the best imaging materials to date, the main sources of outgassing are direct photo/radiolysis of the backbone polymer and the PAG at approximately similar rates, and to a lesser extent, the residual solvent if the PAB is too low. The fate of the outgassed species and their threat to facing optical elements is discussed. (C) 2000 American Vacuum Society. [S0734-211X(oo)02606-8]. C1 Sandia Natl Labs, Livermore, CA 94550 USA. RP Dentinger, PM (reprint author), Sandia Natl Labs, POB 969, Livermore, CA 94550 USA. NR 22 TC 19 Z9 19 U1 1 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD NOV-DEC PY 2000 VL 18 IS 6 BP 3364 EP 3370 DI 10.1116/1.1314383 PG 7 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 384HB UT WOS:000165935800144 ER PT J AU Kedzierski, J Anderson, E Bokor, J AF Kedzierski, J Anderson, E Bokor, J TI Calixarene G-line double resist process with 15 nm resolution aid large area exposure capability SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 44th International Conference on Electron Ion and Photon Beam Technology and Nanofabrication (EIPBN) CY MAY 30-JUN 02, 2000 CL RANCHO MIRAGE, CALIFORNIA SP Amer Vacuum Soc, IEEE Electron Devices Soc, Opt Soc Amer ID ELECTRON-BEAM LITHOGRAPHY AB Methods for combining fast optical lithography and slower high-resolution calixarene electron-beam lithography are presented. These methods rely on dividing the pattern into low-resolution and high-resolution components and exposing each with optical and electron-beam lithography steps, respectively. Patterns produced in this way have a minimum linewidth of 15 nm, and arbitrarily large low-resolution features. Although the procedures take two steps, for many patterns the total exposure time is significantly lower then it would be with a single step calixarene-only process. The optical and electron-beam exposures were aligned using SiGe zero-level alignment marks. A 5 nm misalignment between subsequent electron beam exposures is demonstrated. (C) 2000 American Vacuum Society. [S0734-211X(00)02906-1]. C1 Univ Calif Berkeley, Dept EECS, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Kedzierski, J (reprint author), Univ Calif Berkeley, Dept EECS, Berkeley, CA 94720 USA. RI Bokor, Jeffrey/A-2683-2011 NR 5 TC 3 Z9 3 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD NOV-DEC PY 2000 VL 18 IS 6 BP 3428 EP 3430 DI 10.1116/1.1314386 PG 3 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 384HB UT WOS:000165935800155 ER PT J AU Goodyear, AL Mackenzie, S Olynick, DL Anderson, EH AF Goodyear, AL Mackenzie, S Olynick, DL Anderson, EH TI High resolution inductively coupled plasma etching of 30 nm lines and spaces in tungsten and silicon SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 44th International Conference on Electron Ion and Photon Beam Technology and Nanofabrication (EIPBN) CY MAY 30-JUN 02, 2000 CL RANCHO MIRAGE, CALIFORNIA SP Amer Vacuum Soc, IEEE Electron Devices Soc, Opt Soc Amer ID X-RAY NANOLITHOGRAPHY AB Dry etching of 30 nm features was investigated for x-ray and integrated electronics applications. These typically require etching of either a tungsten absorber layer or a silicon mold. Through the use of an inductively coupled plasma source and accurate control over substrate temperature it was possible to achieve highly anisotropic patterning of tungsten and silicon. Densely patterned features as small as 30 nm and at pitches of 70 nm were etched in tungsten and silicon, to depths of 100 and 200 nm, respectively. (C) 2000 American Vacuum Society. [S0734-211X(00)18406-9]. C1 Oxford Instruments Plasma Technol, Bristol, Avon, England. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Goodyear, AL (reprint author), Oxford Instruments Plasma Technol, Bristol, Avon, England. NR 5 TC 13 Z9 13 U1 1 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD NOV-DEC PY 2000 VL 18 IS 6 BP 3471 EP 3475 DI 10.1116/1.1326922 PG 5 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 384HB UT WOS:000165935800164 ER PT J AU Wei, YY Fan, X Eres, G AF Wei, YY Fan, X Eres, G TI Directed assembly of carbon nanotube electronic circuits by selective area chemical vapor deposition on prepatterned catalyst electrode structures SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 44th International Conference on Electron Ion and Photon Beam Technology and Nanofabrication (EIPBN) CY MAY 30-JUN 02, 2000 CL RANCHO MIRAGE, CALIFORNIA SP Amer Vacuum Soc, IEEE Electron Devices Soc, Opt Soc Amer ID SINGLE-WALL; GROWTH AB Electron-beam lithography was used to pattern Fe thin film electrode structures on silicon dioxide covered Si wafers. The Fe film also serves as a catalyst in subsequent chemical vapor deposition of carbon nanotubes. Chemical vapor deposition was performed in a stainless steel chamber using acetylene at a partial pressure of 100 mTorr and a substrate temperature of 660 degreesC. Transmission electron microscopy images reveal that the carbon nanotubes grown by this method are multiwalled. The carbon nanotubes selectively grow only on the catalyst film and eventually bridge the intentionally designed micron size electrode gap forming carbon nanotube electronic circuits. The resulting devices were characterized by electronic transport measurements in a temperature range from room temperature down to 2 K. (C) 2000 American Vacuum Society. [S0734-211X(oo)05706-1]. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Wei, YY (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. RI Eres, Gyula/C-4656-2017 OI Eres, Gyula/0000-0003-2690-5214 NR 20 TC 7 Z9 7 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD NOV-DEC PY 2000 VL 18 IS 6 BP 3586 EP 3589 DI 10.1116/1.1319709 PG 4 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 384HB UT WOS:000165935800189 ER PT J AU Wendt, JR Krygowski, TW Vawter, GA Blum, O Sweatt, WC Warren, ME Reyes, D AF Wendt, JR Krygowski, TW Vawter, GA Blum, O Sweatt, WC Warren, ME Reyes, D TI Fabrication of diffractive optical elements for an integrated compact optical microelectromechanical system laser scanner SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 44th International Conference on Electron Ion and Photon Beam Technology and Nanofabrication (EIPBN) CY MAY 30-JUN 02, 2000 CL RANCHO MIRAGE, CALIFORNIA SP Amer Vacuum Soc, IEEE Electron Devices Soc, Opt Soc Amer AB We describe the microfabrication of a multilevel diffractive optical element (DOE) onto a microelectromechanical system (MEMS) module as a key element in an integrated compact optical-MEMS laser scanner. The DOE is a four-level off-axis microlens fabricated onto a movable polysilicon shuttle. The microlens is patterned by electron beam lithography and etched by reactive-ion-beam etching. The DOE was fabricated on two generations of MEMS components, each of which is briefly described. The compact design of the laser scanner is based on mounting a MEMS module and a vertical cavity surface-emitting laser onto a fused silica substrate that contains the rest of the optical system. The calculated scan range of the system is +/-4 degrees with a spot size of 0.5 mm. (C) 2000 American Vacuum Society. [S0734-211X(00)01106-9]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Wendt, JR (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 10 TC 3 Z9 3 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD NOV-DEC PY 2000 VL 18 IS 6 BP 3608 EP 3611 DI 10.1116/1.1313580 PG 4 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 384HB UT WOS:000165935800194 ER PT J AU Conroy, JM Kolda, TG O'Leary, DP O'Leary, TJ AF Conroy, JM Kolda, TG O'Leary, DP O'Leary, TJ TI Chromosome identification using hidden Markov models: Comparison with neural networks, singular value decomposition, principal components analysis, and Fisher discriminant analysis SO LABORATORY INVESTIGATION LA English DT Article ID SPEECH RECOGNITION; IMAGE-ANALYSIS; CLASSIFICATION; ABNORMALITIES; SYSTEM AB The analysis of G-banded chromosomes remains the most important tool available to the clinical cytogeneticist. The analysis is laborious when performed manually, and the utility of automated chromosome identification algorithms has been limited by the fact that classification accuracy of these methods seldom exceeds about 80% in routine practice. In this study, we use four new approaches to automated chromosome identification - singular value decomposition (SVD), principal components analysis (PCA), Fisher discriminant analysis (FDA), and hidden Markov models (HMM) - to classify three well-known chromosome data sets (Philadelphia, Edinburgh, and Copenhagen), comparing these approaches with the use of neural networks (NN). We show that the HMM is a particularly robust approach to identification that attains classification accuracies of up to 97% for normal chromosomes and retains classification accuracies of up to 95% when chromosome telomeres are truncated or small portions of the chromosome are inverted. This represents a substantial improvement of the classification accuracy for normal chromosomes, and a doubling in classification accuracy for truncated chromosomes and those with inversions, as compared with NN-based methods. HMMs thus appear to be a promising approach for the automated identification of both normal and abnormal G-banded chromosomes. C1 Armed Forces Inst Pathol, Dept Cellular Pathol, Washington, DC 20306 USA. Inst Def Anal, Ctr Comp Sci, Bowie, MD USA. Sandia Natl Labs, Computat Sci & Math Res Dept, Livermore, CA USA. Univ Maryland, Dept Comp Sci, College Pk, MD 20742 USA. Univ Maryland, Inst Adv Comp Studies, College Pk, MD 20742 USA. Armed Forces Inst Pathol, Dept Cellular Pathol, Washington, DC 20306 USA. RP O'Leary, TJ (reprint author), Armed Forces Inst Pathol, Dept Cellular Pathol, 14th St & Alaska Ave NW, Washington, DC 20306 USA. RI Kolda, Tamara/B-1628-2009 OI Kolda, Tamara/0000-0003-4176-2493 NR 32 TC 12 Z9 12 U1 0 U2 2 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0023-6837 J9 LAB INVEST JI Lab. Invest. PD NOV PY 2000 VL 80 IS 11 BP 1629 EP 1641 DI 10.1038/labinvest.3780173 PG 13 WC Medicine, Research & Experimental; Pathology SC Research & Experimental Medicine; Pathology GA 374XP UT WOS:000165370300003 PM 11092523 ER PT J AU Pan, JW Stein, DT Telang, F Lee, JH Shen, J Brown, P Cline, G Mason, GF Shulman, GI Rothman, DL Hetherington, HP AF Pan, JW Stein, DT Telang, F Lee, JH Shen, J Brown, P Cline, G Mason, GF Shulman, GI Rothman, DL Hetherington, HP TI Spectroscopic imaging of glutamate C4 turnover in human brain SO MAGNETIC RESONANCE IN MEDICINE LA English DT Article DE glutamate turnover; H-1-C-13; MR spectroscopic imaging; human brain metabolism; gray matter; segmentation ID C-13 NMR; 4.1 T AB One-dimensional spectroscopic imaging of C-13-4-glutamate turnover is performed in the human brain with a 6 cc nominal voxel resolution at 4T. Data were acquired with an indirect detection approach using a short spin echo single quantum H-1-C-13 heteronuclear editing method and a 7 cm surface coil with quadrature C-13 decoupling coils. To analyze the data as a function of tissue type, T-1-based image segmentation through the surface coil was performed to determine the gray and white matter contributions to each voxel, The tricarboxylic acid (TCA) cycle rate in gray and white matter was then determined using a two-compartment model with the tissue fractionation derived from the image segmentation. The mean values for the TCA cycle rate for occipital gray and white matter from three volunteers was 0.88 +/- 0.12 and 0.28 +/- 0.13 respectively, in agreement with literature data. (C) 2000 Wiley-Liss, Inc. C1 Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. Montefiore Med Ctr, Albert Einstein Coll Med, Dept Med, Bronx, NY 10467 USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Nathan S Kline Inst Psychiat Res, Orangeburg, NY 10962 USA. Yale Univ, Sch Med, Dept Radiol, New Haven, CT 06510 USA. Yale Univ, Sch Med, Dept Med, New Haven, CT 06510 USA. Yale Univ, Sch Med, Dept Psychiat, New Haven, CT 06510 USA. RP Pan, JW (reprint author), Brookhaven Natl Lab, Dept Med, Bldg 490,POB 5000, Upton, NY 11973 USA. RI Lee, Jing-Huei/J-3978-2016 OI Lee, Jing-Huei/0000-0001-9921-7629 FU NINDS NIH HHS [R01NS33991, P01NS39092, R01NS37257] NR 16 TC 35 Z9 35 U1 0 U2 4 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0740-3194 J9 MAGNET RESON MED JI Magn. Reson. Med. PD NOV PY 2000 VL 44 IS 5 BP 673 EP 679 DI 10.1002/1522-2594(200011)44:5<673::AID-MRM3>3.0.CO;2-L PG 7 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 371DW UT WOS:000165163600003 PM 11064400 ER PT J AU Volkow, ND Wang, GJ Fowler, JS Rooney, WD Felder, CA Lee, JH Franceschi, D Maynard, L Schlyer, DJ Pan, JW Gatley, SJ Springer, CS AF Volkow, ND Wang, GJ Fowler, JS Rooney, WD Felder, CA Lee, JH Franceschi, D Maynard, L Schlyer, DJ Pan, JW Gatley, SJ Springer, CS TI Resting brain metabolic activity in a 4 tesla magnetic field SO MAGNETIC RESONANCE IN MEDICINE LA English DT Article DE functional imaging; PET; visual stimulation; cerebellum; FDG ID AUDITORY-CORTEX; CINGULATE CORTEX; ACOUSTIC NOISE; STIMULATION; DEPRESSION; CATS; MICE AB MRI is a major tool for mapping brain function; thus it is important to assess potential effects on brain neuronal activity attributable to the requisite static magnetic field. This study used positron emission tomography (PET) and F-18-deoxyglucose ((18)FDG) to measure brain glucose metabolism (a measure of brain function) in 12 subjects while their heads were in a 4 T MRI field during the (18)FDG uptake period. The results were compared with those obtained when the subjects were in the earth's field (PET scanner), and when they were in a simulated MRI environment in the PET instrument that imitated the restricted visual field of the MRI experiment. Whole-brain metabolism, as well as metabolism in occipital cortex and posterior cingulate gyrus, was lower in the real (4 T) and simulated (0 T) MRI environments compared with the PET. This suggests that the metabolic differences are due mainly to the visual field differences characteristic of the MRI and PET instruments. We conclude that a static magnetic field of 4 T does not in itself affect this fairly sensitive measure of brain activity. (C) 2000 Wiley-Liss, Inc. C1 Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. SUNY Stony Brook, Dept Psychiat, Stony Brook, NY 11794 USA. SUNY Stony Brook, Dept Chem, Stony Brook, NY 11794 USA. RP Volkow, ND (reprint author), Brookhaven Natl Lab, Dept Med, Bldg 490, Upton, NY 11973 USA. RI Lee, Jing-Huei/J-3978-2016; OI Lee, Jing-Huei/0000-0001-9921-7629; Springer, Charles/0000-0002-5966-2135 NR 28 TC 6 Z9 6 U1 0 U2 2 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0740-3194 J9 MAGNET RESON MED JI Magn. Reson. Med. PD NOV PY 2000 VL 44 IS 5 BP 701 EP 705 DI 10.1002/1522-2594(200011)44:5<701::AID-MRM7>3.0.CO;2-J PG 5 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 371DW UT WOS:000165163600007 PM 11064404 ER PT J AU Lin, SD Cooper, P Fung, J Weier, HUG Rubin, EM AF Lin, SD Cooper, P Fung, J Weier, HUG Rubin, EM TI Genome scan identifies a locus affecting gamma-globin level in human beta-cluster YAC transgenic mice SO MAMMALIAN GENOME LA English DT Article ID GREEK HEREDITARY PERSISTENCE; FETAL HEMOGLOBIN; NORMAL INDIVIDUALS; F-CELLS; GENE; CHROMOSOME; COMPLEX; TRAITS; ADULTS AB Genetic factors affecting postnatal gamma -globin expression-a major modifier of the severity of both beta -thalassemia and sickle cell anemia-have been difficult to study. This is especially so in mice, an organism lacking a globin gene with an expression pattern equivalent to that of human gamma -globin. To model the human beta -cluster in mice, with the goal of screening for loci affecting human gamma -globin expression in vivo, we introduced a human beta -globin cluster YAC transgene into the genome of FVB/N mice. The beta -cluster contained a Greek hereditary persistence of fetal hemoglobin (HPFH) gamma allele, resulting in postnatal expression of human gamma -globin in transgenic mice. The level of human gamma -globin for various F-1 hybrids derived from crosses between the FVB/N transgenics and other inbred mouse strains was assessed. The gamma -globin level of the (C3HeB/FeJ x FVB/N)F-1 transgenic mice was noted to be significantly elevated. To map genes affecting postnatal gamma -globin expression, we performed a 20-centiMorgan (cM) genome scan of a (C3HeB/FeJ x FVB/N)F-1 transgenics x FVB/N back-cross, followed by high-resolution marker analysis of promising loci. From this analysis we mapped a locus within an 18-cM interval of mouse Chromosome (Chr) 1 (LOD = 4.3) that contributes 10.9% of variation in gamma -globin level. Combining transgenic modeling of the human beta -globin gene cluster with quantitative trait analysis, we have identified and mapped a murine locus that impacts on human gamma -globin level in vivo. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Genome Sci Dept, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Dept Subcellular Struct, Berkeley, CA 94720 USA. RP Rubin, EM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Genome Sci Dept, 1 Cyclotron Rd,MS 84-171, Berkeley, CA 94720 USA. FU NHLBI NIH HHS [HL20895] NR 31 TC 2 Z9 2 U1 0 U2 0 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0938-8990 J9 MAMM GENOME JI Mamm. Genome PD NOV PY 2000 VL 11 IS 11 BP 1024 EP 1029 DI 10.1007/s003350010164 PG 6 WC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity GA 367HU UT WOS:000090056300033 PM 11063260 ER PT J AU Schoeler, AC Kaun, TD Krumpelt, M AF Schoeler, AC Kaun, TD Krumpelt, M TI Corrosion behavior of coated steels and Mn- and Co-alloyed steels for separator materials on the cathode side in molten carbonate fuel cells SO MATERIALS AND CORROSION-WERKSTOFFE UND KORROSION LA English DT Article AB The corrosion behavior and the electrical resistivity of the oxide scale that forms on alternative materials for bipolar plates in molten carbonate fuel cells (MCFCs) were investigated. Commercial stainless steels (SS) containing cobalt (Haynes 556) and manganese (Nitronic 30, Nitronic 50, and Nitronic 60) were tested under cathodic MCFC conditions Additionally, 316L SS coated with cobalt by thermal spraying was studied. Oxide-scale resistivity measurements were coupled with observations of microstructural/compositional changes over time. All tested materials formed multilayered oxide scales. The composition of these phases was the key factor in determining the interfacial electrical resistivity. The high cobalt content of Haynes 556 (18 wt%) did not decrease its electrical resistivity or improve its corrosion resistance. Thus, Go-containing stainless steels, such as Haynes 556, do not appear to be candidate bipolar plate materials for MCFCs. In contrast, the cobalt coating on 316L SS did lead to improved corrosion resistance. The Nitronic alloys formed Mn-containing oxide scales, which appear to have a beneficial effect on lowering the resistivity of the oxide scale. The corrosion resistance of these Mn-containing stainless steels was greater than that of 316LSS, the present bipolar plate material. C1 Argonne Natl Lab, Div Chem Technol, Electrochem Technol Program, Argonne, IL 60439 USA. RP Schoeler, AC (reprint author), Argonne Natl Lab, Div Chem Technol, Electrochem Technol Program, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 13 TC 4 Z9 4 U1 0 U2 9 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0947-5117 J9 MATER CORROS JI Mater. Corros. PD NOV PY 2000 VL 51 IS 11 BP 797 EP 807 PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 378XN UT WOS:000165610800005 ER PT J AU Burmeister, J Kota, C Maughan, RL Spokas, JJ Coderre, JA Ma, RM Wielopolski, L AF Burmeister, J Kota, C Maughan, RL Spokas, JJ Coderre, JA Ma, RM Wielopolski, L TI A conducting plastic simulating brain tissue SO MEDICAL PHYSICS LA English DT Article DE tissue equivalent plastic; neutron dosimetry; BNCT; BNCEFNT ID NEUTRON-CAPTURE THERAPY; RESEARCH REACTOR; DOSIMETRY; BEAMS AB A new conducting plastic has been composed which accurately simulates the photon and neutron absorption properties of brain tissue. This tissue-equivalent (TE) plastic was formulated to match the hydrogen and nitrogen constituents recommended by ICRU Report #44 for brain tissue. Its development was initiated by the inability of muscle tissue-equivalent plastic to closely approximate brain tissue with respect to low-energy neutron interactions. This new plastic is particularly useful as an electrode in TE dosimetry devices for boron neutron capture therapy (BNCT), which utilizes low-energy neutrons for radiotherapy of the brain, Absorbed dose measurements in a clinical BNCT beam using a proportional counter constructed from this TE plastic show good agreement with Monte Carlo calculations. (C) 2000 American Association of Physicists in Medicine. [S0094-2405(00)02211-2]. C1 Harper Grace Hosp, Gershenson Radiat Oncol Ctr, Karmanos Canc Inst, Detroit, MI 48201 USA. Wayne State Univ, Detroit, MI 48201 USA. Exradin Inc, Lisle, IL 60532 USA. Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. RP Burmeister, J (reprint author), Harper Grace Hosp, Gershenson Radiat Oncol Ctr, Karmanos Canc Inst, 3990 John R, Detroit, MI 48201 USA. NR 23 TC 9 Z9 9 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-2405 J9 MED PHYS JI Med. Phys. PD NOV PY 2000 VL 27 IS 11 BP 2560 EP 2564 DI 10.1118/1.1320043 PG 5 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 377BK UT WOS:000165491900011 PM 11128308 ER PT J AU Mitlin, D Radmilovic, V Morris, JW AF Mitlin, D Radmilovic, V Morris, JW TI Catalyzed precipitation in Al-Cu-Si SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID THIN-FILM INTERCONNECTS; THETA-' PLATES; GE ALLOY; ELECTROMIGRATION; NUCLEATION; EVOLUTION; MECHANISM; GROWTH; LINES AB The work reported here concerns the effect of Si on the precipitation of theta' phase (metastable Al2Cu) during the isothermal aging of Al-2Cu-1Si (wt pet). The binary alloys Al-2Cu and Al-1Si were studied for comparison. Only two precipitate phases were detected: essentially pure Si in Al-1Si and Al-2Cu-1Si, and theta' (metastable Al2Cu) in Al-2Cu and Al-2Cu-1Si. On aging the ternary alloy at 225 degreesC, Si precipitates first and catalyzes the theta' phase. The precipitates in the ternary alloy are smaller, are more densely distributed, have lower aspect ratios, and coarsen more slowly than those in the binary Al2Cu aged at the same temperature. While the shapes of individual theta' precipitates in binary Al-2Cu are strongly affected by the kinetic problem of nucleating growth ledges, which produces a significant scatter in the aspect ratio for samples of given thickness, the overall evolution of particle shape with size follows the predictions of the Khachaturyan-Hairapetyan (KH) thermoelastic theory, which reduces to kappa = L/d proportional to rootL at large sizes. The KH theory provides an estimate for the interfacial tension of the broad Al-theta' interface of 85 to 96 mJ/m(2), which is near the values for other low-energy interfaces in Al, such as the twin boundary energy (100 mJ/m(2)) and the antiphase boundary energy in delta' Al3Li (70 mJ/m(2)). Si and theta' precipitates in Al-2Cu-1Si have a strong elastic interaction because of their compensating strain fields. This elastic interaction promotes the nucleation of theta' precipitates on Si, decreases the expected aspect ratio of theta', and inhibits coarsening. Finally, Si precipitation in ternary Al-2Cu-1Si differs from that in binary Al-1Si in that the Si precipitates are coarser, more equiaxed, and more extensively twinned. These changes appear to be effects of Cu, which increases the solubility of Si in Al and adsorbs on the Si-Al interface, promoting twinning by a "step-poisoning" effect at the interface. C1 Univ Calif Berkeley, Dept Mat Sci & Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Adv Mat, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Natl Ctr Electron Microscopy, Berkeley, CA 94720 USA. RP Mitlin, D (reprint author), Univ Calif Berkeley, Dept Mat Sci & Engn, Berkeley, CA 94720 USA. RI Mitlin , David /M-5328-2016 OI Mitlin , David /0000-0002-7556-3575 NR 51 TC 23 Z9 24 U1 1 U2 11 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086 USA SN 1073-5623 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD NOV PY 2000 VL 31 IS 11 BP 2697 EP 2711 DI 10.1007/BF02830329 PG 15 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 375HJ UT WOS:000165393200001 ER PT J AU Uwakweh, ONC Liu, ZT Jordan, A Chakoumakos, B Spooner, S Maziasz, P AF Uwakweh, ONC Liu, ZT Jordan, A Chakoumakos, B Spooner, S Maziasz, P TI Neutron diffraction and phase evolution of the mechanically alloyed intermetallic compound zeta-FeZn13 SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID FE; KINETICS; ZN AB High-energy ball milling with subsequent annealing is used to synthesize the intermetallic compound zeta -FeZn13. The mechanically alloyed phase in the as-milled state is determined to be nonequilibrium, or metastable. Transmission electron microscopy (TEM) studies show a highly defective microstructure with undefined grain areas, and the alloy can be described as a mechanical mixture of elemental Fe and Zn, based on neutron diffraction measurements. Characteristic stages associated with its transformation to the equilibrium state are identified based on differential scanning calorimetry (DSC) measurements. The activation energies corresponding to these stages are 128, 202, and 737 kJ/mole, respectively, with increasing transformation temperatures. The first stage is related to limited atomic diffusion or rearrangements, such as recovery, during thermal treatment, while the second stage depicts continued recrystallization and long-range atomic diffusion leading to a stable phase formation. The third and final stage marks structural decomposition of the equilibrium structure due to phase transition. Neutron diffraction of the equilibrium alloy confirmed that the structure is C2/m, with lattice parameters of a = 13.40995 Angstrom, b = 7.60586 Angstrom, c = 5.07629 Angstrom, and beta = 127 deg 18 minutes. The atomic positions of Fe and Zn compared well to reported values. C1 Univ Cincinnati, Dept Mat Sci & Engn, Cincinnati, OH 45221 USA. Oak Ridge Natl Lab, Alloy Behav & Design Grp, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Uwakweh, ONC (reprint author), Univ Cincinnati, Dept Mat Sci & Engn, Cincinnati, OH 45221 USA. RI Chakoumakos, Bryan/A-5601-2016 OI Chakoumakos, Bryan/0000-0002-7870-6543 NR 15 TC 6 Z9 6 U1 1 U2 3 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086 USA SN 1073-5623 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD NOV PY 2000 VL 31 IS 11 BP 2739 EP 2745 DI 10.1007/BF02830333 PG 7 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 375HJ UT WOS:000165393200005 ER PT J AU Uwakweh, O Jordan, A Maziasz, P AF Uwakweh, O Jordan, A Maziasz, P TI Thermal transformations in mechanically alloyed Fe-Zn-Si materials SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID GALVANIZED COATINGS AB The ball milling of elemental powders corresponding to Gamma (Fe3Zn10) + 0.12 wt pet Si; Gamma (1) (Fe5Zn21) + 0.12 wt pet Si; delta (FeZn7) + 0.12 wt pet Si; and zeta (FeZn13) + 0.12 wt pet Si composition ratios yields crystalline, mechanically alloyed phases. Differential scanning calorimetry (DSC) measurements of these materials show that they evolve differently, with well-defined characteristic stages. The activation energies for processes corresponding to these stages, based on kinetic analyses, are determined and correlated to microstructural evolvements. The processes occurring during the first stage below 250 degreesC, for all of the materials studied using X-ray diffraction (XRD) analysis, are associated with release of strain, recovery, and limited atomic diffusion. The activation energies for recovery processes are 120 kJ/mole for the Gamma + 0.12 wt pet Si, 131 kJ/mole for delta + 0.12 wt pet Si, and 96 kJ/mole for zeta + 0.12 wt pet Si alloys. At higher temperatures, recrystallization and other structural transformations occur with activation energies of 130 and 278 kJ/mole for Gamma + 0.12 wt % Si; of 161 kJ/mole for Gamma (1) + 0.12 wt pet Si; of 167 and 244 kJ/mole for delta + 0.12 wt pet Si; and of 641 kJ/mole for the zeta + 0.12 wt pet Si. In addition, a eutectic reaction at 420 degreesC +/- 3 degreesC, corresponding to the Zn-Si system, and a melting of Zn in Fe-Zn systems are observed for the zeta + 0.12 wt pet Si material. The relation of FeSi formation in the Sandelin process is discussed. C1 Univ Cincinnati, Dept Mat Sci & Engn, Cincinnati, OH 45221 USA. Oak Ridge Natl Lab, Alloy Behav & Design Grp, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Uwakweh, O (reprint author), Univ Cincinnati, Dept Mat Sci & Engn, Cincinnati, OH 45221 USA. OI Maziasz, Philip/0000-0001-8207-334X NR 32 TC 2 Z9 2 U1 0 U2 3 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086 USA SN 1073-5623 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD NOV PY 2000 VL 31 IS 11 BP 2747 EP 2754 DI 10.1007/BF02830334 PG 8 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 375HJ UT WOS:000165393200006 ER PT J AU Davies, RW Smith, MT Oliver, HE Khaleel, MA Pitman, SG AF Davies, RW Smith, MT Oliver, HE Khaleel, MA Pitman, SG TI Weld metal ductility in aluminum tailor welded blanks SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article AB The objective of the research described in this article was to characterize and numerically describe the ductility of weld material in aluminum tailor welded blanks under uniaxial tension conditions. Aluminum tailor welded blanks consist of multiple thickness and alloy sheet materials welded together into a single, variable thickness blank. To evaluate the mechanical properties of the weld material in these tailor welded blanks, a series of tensile specimens containing varying ratios of weld and monolithic material in the gage area of the specimen were tested. These experimental results show that increasing the amount of weld in the cross-sectional area of the specimen decreases the ductility of the specimen and that the weld characteristics have a pronounced impact on ductility. Using the experimental results and classical tensile instability and necking models, a numerical model was developed to describe the ductility of the weld metal. The model involves basic material properties and an initial imperfection level in both the weld and monolithic materials. The specimens studied were produced from 1- to 2-mm AA5182-O aluminum alloy sheet material welded into blanks using an autogenous gas tungsten are welding process. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. Reynolds Met Co, Chester, VA USA. RP Davies, RW (reprint author), Pacific NW Natl Lab, Richland, WA 99352 USA. OI khaleel, mohammad/0000-0001-7048-0749 NR 14 TC 31 Z9 31 U1 1 U2 4 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086 USA SN 1073-5623 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD NOV PY 2000 VL 31 IS 11 BP 2755 EP 2763 DI 10.1007/BF02830335 PG 9 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 375HJ UT WOS:000165393200007 ER PT J AU Krot, AN Brearley, AJ Petaev, MI Kallemeyn, GW Sears, DWG Benoit, PH Hutcheon, ID Zolensky, ME Keil, K AF Krot, AN Brearley, AJ Petaev, MI Kallemeyn, GW Sears, DWG Benoit, PH Hutcheon, ID Zolensky, ME Keil, K TI Evidence for low-temperature growth of fayalite and hedenbergite in MacAlpine Hills 88107, an ungrouped carbonaceous chondrite related to the CM-CO clan SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID EARLY SOLAR-SYSTEM; COMPOSITIONAL CLASSIFICATION; AQUEOUS ALTERATION; ASTEROIDAL ALTERATION; OXYGEN-ISOTOPE; CV3 CHONDRITES; BASALT GLASS; NEBULA; MOKOIA; CONDENSATION AB The carbonaceous chondrite MacAlpine Hills (MAC) 88107 has bulk composition and mineralogy that are intermediate between those of CO and CM chondrites. This meteorite experienced minor alteration and a low degree of thermal metamorphism (petrologic type 3.1) and escaped post-accretional brecciation. The alteration resulted in the formation of fayalite (Fa(90-100)), Al-free hedenbergite (similar to Fs(50)Wo(50)), phyllosilicates (saponite-serpentine intergrowths), magnetite, and Ni-bearing sulfides (pyrrhotite and pentlandite). Fayalite and hedenbergite typically occur as veins, which start at the opaque nodules in the chondrule peripheries, crosscut fine-grained rims and either terminate at the boundaries with the neighboring fine-grained rims or continue as layers between these rims. These observations suggest that fayalite and hedenbergite crystallized after accretion and compaction of the fine-grained rims. Fayalite also overgrows isolated forsteritic (Fa(1-5)) and fayalitic (Fa(20-40)) olivine grains without any evidence for Fe-Mg interdiffusion; it also replaces massive magnetite-sulfide grains. The initial Mn-53/Mn-55 ratio of (1.58 +/- 0.26) x 10(-6) in the MAC 88107 fayalite corresponds to an age difference between the formation of fayalite and refractory inclusions in Allende of either similar to9 or 18 Ma, depending upon the value of the solar system initial abundance of Mn-53 used in age calculations. Formation of secondary fayalite and hedenbergite requires mobilization and transport of Ca, Si, and Fe either through a high-temperature gaseous phase (Hua and Buseck, 1995) or low-temperature aqueous solution (Krot et al., 1998a,b). The high-temperature nebular model for the origin of fayalite (Hua and Buseck, 1995) fails to explain (a) formation of fayalite-hedenbergite assemblages after accretion of fine-grained rims that lack any evidence for high-temperature processing; (b) extreme fractionation of refractory lithophile elements of similar volatility, Ca and Al, in hedenbergite; and (c) absence of Fe-Mg interdiffusion along fayalite-forsterite boundaries. We conclude that fayalite and hedenbergite in MAC 88107 formed during late-stage, low-temperature (approximately 150-200 degreesC) aqueous alteration. The data for MAC 88107 extend the evidence for an early onset of aqueous activity on chondrite parent bodies and reinforce the conclusion that liquid water played an important role in the chemical and mineralogical evolution of the first chondritic planetesimals. C1 Univ Hawaii, Sch Ocean & Earth Sci & Technol, Hawaii Inst Geophys & Planetol, Honolulu, HI 96822 USA. Univ New Mexico, Albuquerque, NM 87131 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Tokyo Metropolitan Univ, Dept Math, Grad Sch Sci, Tokyo 1920397, Japan. Univ Arkansas, Dept Chem & Biochem, Fayetteville, AR 72701 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Krot, AN (reprint author), Univ Hawaii, Sch Ocean & Earth Sci & Technol, Hawaii Inst Geophys & Planetol, Honolulu, HI 96822 USA. NR 59 TC 27 Z9 27 U1 1 U2 5 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 0026-1114 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD NOV PY 2000 VL 35 IS 6 BP 1365 EP 1386 PG 22 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 385LF UT WOS:000166005400021 ER PT J AU Majidi, V AF Majidi, V TI Capillary electrophoresis inductively coupled plasma mass spectrometry SO MICROCHEMICAL JOURNAL LA English DT Article DE capillary electrophoresis; inductively coupled plasma mass spectrometry ID PERFORMANCE LIQUID-CHROMATOGRAPHY; ATOMIC EMISSION-SPECTROMETRY; ELEMENTAL SPECIATION; ZONE-ELECTROPHORESIS; SELENIUM SPECIATION; NEBULIZER INTERFACE; ELECTROSPRAY; MS; EXTRACTS; DESIGN AB Chemical speciation (extraction of elemental information and identification of molecular environment for an analyte in a complex sample) has been a long sought after goal for analytical chemists. Recently, because of successful developments in more sensitive element-specific detectors and gentle separation schemes, which preserve the true chemical information in a real sample, routine speciation experiments are becoming a common occurrence in the scientific literature. For many reasons, the combination of capillary electrophoresis (for separation of different chemical species) with inductively coupled plasma mass spectrometry (for element and isotope specific detection) has emerged as the method of choice for these analyses. In this article the basic principles of capillary electrophoresis inductively coupled plasma mass spectrometry are discussed. Design consideration for instrument interface, anticipated difficulties with speciation experiments and applications for specific matrices and analytes are also presented in this article. (C) 2000 Published by Elsevier Science B.V. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Majidi, V (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, MS K484, Los Alamos, NM 87545 USA. NR 36 TC 24 Z9 25 U1 2 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0026-265X J9 MICROCHEM J JI Microchem J. PD NOV PY 2000 VL 66 IS 1-3 BP 3 EP 16 DI 10.1016/S0026-265X(00)00062-X PG 14 WC Chemistry, Analytical SC Chemistry GA 382PH UT WOS:000165831100002 ER PT J AU Nyman, M Gu, BX Wang, LM Ewing, RC Nenoff, TM AF Nyman, M Gu, BX Wang, LM Ewing, RC Nenoff, TM TI Synthesis and characterization of a new microporous cesium silicotitanate (SNL-B) molecular sieve SO MICROPOROUS AND MESOPOROUS MATERIALS LA English DT Article DE molecular sieve; silicotitanates; Cs and Sr radionuclides; electron beam irradiation ID SODIUM TITANIUM SILICATE; ION-EXCHANGE PROPERTIES; SOLID-STATE NMR; SI-29 MAS NMR; CRYSTAL-STRUCTURE; CATALYTIC PROPERTIES; TITANOSILICATE; DIFFRACTION; ZEOLITE; WASTE AB Ongoing hydrothermal Cs-Ti-Si-O-H2O phase investigations has produced several new ternary phases including a novel microporous Cs-silicotitanate molecular sieve, SNL-B with the approximate formula of CS3TiSi3O9.5. 3H(2)O. SNL-B is only the second molecular sieve, Cs-silicotitanate phase reported to have been synthesized by hydrothermal methods. Crystallites are very small (0.1 x 2 mum(2)) with a blade-like morphology. SNL-B is confirmed to be a three-dimensional molecular sieve by a variety of characterization techniques (N-2 adsorption, ion exchange, water adsorption/desorption, solid state cross polarization-magic angle spinning nuclear magnetic resonance). SNL-B is able to desorb and adsorb water from its pores while retaining its crystal structure and exchanges Cs cations readily. Additional techniques were used to describe fundamental properties (powder X-ray diffraction, FTIR,Si-29 and Cs-133 MAS NMR, DTA, SEM/EDS, ion selectivity, and radiation stability). The phase relationships of metastable SNL-B to other hydrothermally synthesized Cs-Ti-Si-O-H2O phases are discussed, particularly its relationship to a Cs-silicotitanate analogue of pharmacosiderite, and a novel condensed phase, a polymorph of Cs2TiSi6O15 (SNL-A). (C) 2000 Elsevier Science B.V. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Michigan, Dept Nucl Engn & Radiol Sci, Ann Arbor, MI 48109 USA. RP Nenoff, TM (reprint author), Sandia Natl Labs, POB 5800,MS 0710, Albuquerque, NM 87185 USA. NR 49 TC 19 Z9 19 U1 6 U2 13 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-1811 J9 MICROPOR MESOPOR MAT JI Microporous Mesoporous Mat. PD NOV PY 2000 VL 40 IS 1-3 BP 115 EP 125 DI 10.1016/S1387-1811(00)00247-X PG 11 WC Chemistry, Applied; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary SC Chemistry; Science & Technology - Other Topics; Materials Science GA 373ZP UT WOS:000165320200011 ER PT J AU Lenosky, TJ Sadigh, B Alonso, E Bulatov, VV de la Rubia, TD Kim, J Voter, AF Kress, JD AF Lenosky, TJ Sadigh, B Alonso, E Bulatov, VV de la Rubia, TD Kim, J Voter, AF Kress, JD TI Highly optimized empirical potential model of silicon SO MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING LA English DT Article ID ABINITIO MOLECULAR-DYNAMICS; TOTAL-ENERGY CALCULATIONS; EMBEDDED-ATOM METHOD; WAVE BASIS-SET; AB-INITIO; INTERATOMIC POTENTIALS; STRUCTURAL ENERGIES; AMORPHOUS-SILICON; SI(100) SURFACE; METALS AB We fit an empirical potential for silicon using the modified embedded atom (MEAM) functional form, which contains a nonlinear function of a sum of pairwise and three-body terms. The three-body term is similar to the Stillinger-Weber form. We parametrized our model using five cubic splines, each with 10 fitting parameters, and fitted the parameters to a large database using the force-matching method. Our model provides a reasonable description of energetics for all atomic coordinations, Z, from the dimer (Z = 1) to fee and hcp (Z = 12). It accurately reproduces phonons and elastic constants, as well as point defect energetics. It also provides a good description of reconstruction energetics for both the 30 degrees and 90 degrees partial dislocations. Unlike previous models, our model accurately predicts formation energies and geometries of interstitial complexes-small dusters, interstitial-chain and planar {311} defects. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Ohio State Univ, Dept Phys, Columbus, OH 43210 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Lenosky, TJ (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. OI Voter, Arthur/0000-0001-9788-7194 NR 62 TC 85 Z9 86 U1 3 U2 22 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0965-0393 J9 MODEL SIMUL MATER SC JI Model. Simul. Mater. Sci. Eng. PD NOV PY 2000 VL 8 IS 6 BP 825 EP 841 DI 10.1088/0965-0393/8/6/305 PG 17 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 383YC UT WOS:000165911400006 ER PT J AU Riccillo, PM Collavino, MM Grasso, DH England, R de Bruijn, FJ Aguilar, OM AF Riccillo, PM Collavino, MM Grasso, DH England, R de Bruijn, FJ Aguilar, OM TI A guaB mutant strain of Rhizobium tropici CIAT899 pleiotropically defective in thermal tolerance and symbiosis SO MOLECULAR PLANT-MICROBE INTERACTIONS LA English DT Article DE guanine biosynthesis; nodule development; prototrophy ID PHASEOLUS-VULGARIS L; GTP-BINDING PROTEIN; AMINO-ACID STARVATION; ESCHERICHIA-COLI; BACILLUS-SUBTILIS; HEAT-SHOCK; NITROGEN-FIXATION; PURINE AUXOTROPHS; HIGH-TEMPERATURE; MELILOTI AB Rhizobium tropici strain CIAT899 displays a high intrinsic thermal tolerance, and had been used in this work to study the molecular basis of bacterial responses to high temperature. We generated a collection of R. tropici CIAT899 mutants affected in thermal tolerance using Tn5-luxAB mutagenesis and described the characterization of a mutant strain, CIAT899-10T, that fails to grow under conditions of high temperature. Strain CIAT899-10T carries a single transposon insertion in a gene showing a high degree of similarity with the guaB gene of Escherichia coli and other organisms, encoding the enzyme inosine monophosphate dehydrogenase, The guaB strain CIAT899-10T does not require guanine for growth due to an alternative pathway via xanthine dehydrogenase and, phenotypically, in addition to the thermal sensitivity, the mutant is also defective in symbiosis with beans, forming nodules that lack rhizobial content. Guanine and its precursors restore wild-type tolerance to grow at high temperature. Our data show that, in R. tropici, the production of guanine via inosine monophosphate dehydrogenase is essential for growth at extreme temperatures and for effective nodulation. C1 Natl Univ La Plata, Fac Ciencias Exactas, Inst Bioquim & Biol Mol, RA-1900 La Plata, Argentina. Univ Cent Lancashire, Dept Appl Biol, Preston PR1 2HE, Lancs, England. Michigan State Univ, DOE, Plant Res Lab, E Lansing, MI 48824 USA. Michigan State Univ, Dept Microbiol, E Lansing, MI 48824 USA. RP Aguilar, OM (reprint author), Natl Univ La Plata, Fac Ciencias Exactas, Inst Bioquim & Biol Mol, RA-1900 La Plata, Argentina. NR 46 TC 13 Z9 14 U1 0 U2 2 PU AMER PHYTOPATHOLOGICAL SOC PI ST PAUL PA 3340 PILOT KNOB ROAD, ST PAUL, MN 55121 USA SN 0894-0282 J9 MOL PLANT MICROBE IN JI Mol. Plant-Microbe Interact. PD NOV PY 2000 VL 13 IS 11 BP 1228 EP 1236 DI 10.1094/MPMI.2000.13.11.1228 PG 9 WC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Plant Sciences SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Plant Sciences GA 366BW UT WOS:000089985800008 PM 11059489 ER PT J AU Jiang, K Zhong, B Gilvary, DL Corliss, BC Hong-Geller, E Wei, S Djeu, JY AF Jiang, K Zhong, B Gilvary, DL Corliss, BC Hong-Geller, E Wei, S Djeu, JY TI Pivotal role of phosphoinositide-3 kinase in regulation of cytotoxicity in natural killer cells SO NATURE IMMUNOLOGY LA English DT Article ID PHOSPHATIDYLINOSITOL 3-KINASE; PROTEIN-KINASE; T-CELLS; TYROSINE KINASE; ADAPTER PROTEIN; EXCHANGE FACTOR; ACTIVATION; RECEPTOR; PATHWAY; RAC AB The mitogen-activated protein kinase-extracellular signal-regulated kinase signaling element (MAPK-ERK) plays a critical role in natural killer (NK) cell lysis of tumor cells, but its upstream effecters were previously unknown. We show that inhibition of phosphoinositide-3 kinase (PI3K) in NK cells blocks p21-activated kinase 1 (PAK1), MAPK kinase (MEK) and ERK activation by target cell ligation, interferes with perforin and granzyme B movement toward target cells and suppresses NK cytotoxicity. Dominant-negative N17Rac1 and PAK I mimic the suppressive effects of PI3K inhibitors, whereas constitutively active V12Rac1 has the opposite effect. V12Rac1 restores the activity of downstream effecters and lytic function in LY294002- or wortmannin-treated, but not PD98059-treated, NK cells,These results document a specific PI3K-->Rac1-->PAK1->MEK-->ERK pathway in NK cells that effects lysis. C1 Univ S Florida, Coll Med, Dept Interdisciplinary Oncol, H Lee Moffitt Canc Ctr,Immunol Program, Tampa, FL 33612 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Djeu, JY (reprint author), Univ S Florida, Coll Med, Dept Interdisciplinary Oncol, H Lee Moffitt Canc Ctr,Immunol Program, Tampa, FL 33612 USA. EM djeu@moffitt.usf.edu FU NCI NIH HHS [CA83146] NR 32 TC 222 Z9 228 U1 0 U2 3 PU NATURE PUBLISHING GROUP PI NEW YORK PA 75 VARICK ST, 9TH FLR, NEW YORK, NY 10013-1917 USA SN 1529-2908 J9 NAT IMMUNOL JI Nat. Immunol. PD NOV PY 2000 VL 1 IS 5 BP 419 EP 425 DI 10.1038/80859 PG 7 WC Immunology SC Immunology GA 369PL UT WOS:000165076100015 PM 11062502 ER PT J AU Terwilliger, TC AF Terwilliger, TC TI Structural genomics in North America SO NATURE STRUCTURAL BIOLOGY LA English DT Article AB Structural genomics in North America has moved remarkably quickly from ideas to pilot projects. Just three years ago, the field was only a concept, independently being discussed by its many inventors. Now it is already a well-organized, increasingly-funded, consortium-based effort to determine protein structures on a large scale. C1 Los Alamos Natl Lab, Div Biosci, Los Alamos, NM 87545 USA. RP Terwilliger, TC (reprint author), Los Alamos Natl Lab, Div Biosci, Mail Stop M888, Los Alamos, NM 87545 USA. RI Terwilliger, Thomas/K-4109-2012 OI Terwilliger, Thomas/0000-0001-6384-0320 NR 0 TC 82 Z9 86 U1 0 U2 2 PU NATURE AMERICA INC PI NEW YORK PA 345 PARK AVE SOUTH, NEW YORK, NY 10010-1707 USA SN 1072-8368 J9 NAT STRUCT BIOL JI Nat. Struct. Biol. PD NOV PY 2000 VL 7 SU S BP 935 EP 939 DI 10.1038/80700 PG 5 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 563YQ UT WOS:000176285900005 PM 11103992 ER PT J AU Abola, E Kuhn, P Earnest, T Stevens, RC AF Abola, E Kuhn, P Earnest, T Stevens, RC TI Automation of X-ray crystallography SO NATURE STRUCTURAL BIOLOGY LA English DT Article ID STRUCTURAL BIOLOGY; CRYOCRYSTALLOGRAPHY; DESIGN AB Structure-based biological discovery is entering a new era with the development of industrialized macromolecular structure determination pipelines. Intense, highly focused X-rays from integrated synchrotron radiation beam lines combined with significant advances in protein expression, purification, and micro-crystallization automation allow for the full streamlining of the traditionally tedious and time consuming process of determining the three dimensional structures of macromolecules. C1 Scripps Res Inst, Res Inst, Dept Mol Biol, La Jolla, CA 92037 USA. Syrrx Inc, San Diego, CA 92121 USA. Stanford Univ, Stanford Synchrotron Radiat Lab, Stanford, CA 94305 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley Ctr Struct Biol, Phys Biosci Div, Berkeley, CA 94720 USA. Novartis Res Fdn, Genom Inst, San Diego, CA 92121 USA. RP Stevens, RC (reprint author), Scripps Res Inst, Res Inst, Dept Mol Biol, La Jolla, CA 92037 USA. RI huang, hongqi/N-1473-2014; Stevens, Raymond/K-7272-2015 OI Stevens, Raymond/0000-0002-4522-8725 NR 13 TC 131 Z9 137 U1 1 U2 13 PU NATURE AMERICA INC PI NEW YORK PA 345 PARK AVE SOUTH, NEW YORK, NY 10010-1707 USA SN 1072-8368 J9 NAT STRUCT BIOL JI Nat. Struct. Biol. PD NOV PY 2000 VL 7 SU S BP 973 EP 977 DI 10.1038/80754 PG 5 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 563YQ UT WOS:000176285900017 PM 11104004 ER PT J AU Gifford, AN Park, MH Kash, TL Herman, LM Park, EH Gatley, SJ Volkow, ND AF Gifford, AN Park, MH Kash, TL Herman, LM Park, EH Gatley, SJ Volkow, ND TI Effect of amphetamine-induced dopamine release on radiotracer binding to D-1 and D-2 receptors in rat brain striatal slices SO NAUNYN-SCHMIEDEBERGS ARCHIVES OF PHARMACOLOGY LA English DT Article DE dopamine; brain slice; positron emission tomography; amphetamine ID VESICULAR TRANSMITTER STORES; ENDOGENOUS DOPAMINE; KINETIC-PROPERTIES; ACETYLCHOLINE NEUROTRANSMISSION; SYNTHESIS INHIBITORS; RACLOPRIDE BINDING; C-11 RACLOPRIDE; H-3 RACLOPRIDE; MOUSE-BRAIN; IN-VIVO AB The in vivo binding of positron emission tomography (PET) and single photon emission computer tomography (SPECT) radiotracers to dopamine D-2 receptors in the striatum can be influenced by competition with endogenous dopamine. The present study was undertaken to determine if a similar inhibition of radiotracer binding to dopamine receptors could be observed following pharmacologically-evoked dopamine release in rat brain striatal slices. Striatal slices were incubated in a large volume of oxygenated Krebs saline and exposed to amphetamine or methamphetamine to evoke dopamine release within the slice. Amphetamine and methamphetamine, at concentrations up to 30 muM, reduced [H-3]raclopride binding in the slices by 77% and 86%, respectively, with 50% inhibition at 1.6 muM amphetamine or 3.0 muM methamphetamine. Neither drug produced a significant effect on binding of [H-3]SCH 23390 in the slices. This suggests that dopamine was able to interfere with radiotracer binding to D-2 but not D-1 receptors. The dopamine uptake blockers, cocaine and methylphenidate, had relatively little effect by themselves on [H-3]raclopride binding but, by inhibiting amphetamine-induced dopamine release, significantly reduced inhibition of [H-3]raclopride binding by a low (3 muM) amphetamine concentration. At a higher (30 muM) amphetamine concentration the inhibition of [H-3]raclopride binding was not antagonized by uptake blockers and data obtained from homogenate binding experiments indicated a direct displacement of [H-3]raclopride binding by amphetamine at this concentration. In conclusion the data obtained in the present study demonstrate that the effects of amphetamine on striatal radiotracer accumulation observed in PET and SPECT can also be observed in brain slices in vitro and, at least at low amphetamine concentrations, are mediated by competition with released dopamine. C1 Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. Sookmyung Womens Univ, Coll Pharm, Seoul, South Korea. RP Gifford, AN (reprint author), Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. RI Kash, Thomas/G-9625-2013 FU NIDA NIH HHS [1R01DA/NS11552-01] NR 31 TC 13 Z9 13 U1 1 U2 3 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0028-1298 J9 N-S ARCH PHARMACOL JI Naunyn-Schmiedebergs Arch. Pharmacol. PD NOV PY 2000 VL 362 IS 4-5 BP 413 EP 418 DI 10.1007/s002100000293 PG 6 WC Pharmacology & Pharmacy SC Pharmacology & Pharmacy GA 375UB UT WOS:000165418700013 PM 11111836 ER PT J AU Zhong, K Li, X Shachar-Hill, Y Picart, F Wishnia, A Springer, CS AF Zhong, K Li, X Shachar-Hill, Y Picart, F Wishnia, A Springer, CS TI Magnetic susceptibility shift selected imaging (MESSI) and localized (H2O)-H-1 spectroscopy in living plant tissues SO NMR IN BIOMEDICINE LA English DT Article DE MRI; susceptibility agent imaging; maize; transcytolemmal water transport ID WATER-EXCHANGE; IN-VIVO; NMR; MUSCLE; BRAIN AB Maize root segments permeated with aqueous solutions of the paramagnetic agents GdDTPA(2-) or DyDTPA-BMA display two well-resolved NMR peaks corresponding to the signals from intracellular and extracellular (H2O)-H-1, which arise from well-understood bulk magnetic susceptibility effects. This allows each component to be studied separately. images obtained at each frequency with MESSI editing, and single- and multiple-voxel ('spectroscopic imaging') localized spectra, clearly indicate that the agents permeate into the interstitial spaces, and into the longitudinal (xylem/phloem) channels in the stele (core) of the root, confirming earlier assessments. We believe these are the first images of a multicellular tissue acquired in vivo exclusively from the intracellular water proton resonance. This method can be further exploited to study water transport in similar systems. Copyright (C) 2000 John Wiley & Sons, Ltd. C1 SUNY Stony Brook, Dept Chem, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. New Mexico State Univ, Dept Chem & Biochem, Las Cruces, NM 88003 USA. RP Wishnia, A (reprint author), SUNY Stony Brook, Dept Chem, Stony Brook, NY 11794 USA. RI Shachar-Hill, Yair/B-6165-2013; OI Shachar-Hill, Yair/0000-0001-8793-5084; Springer, Charles/0000-0002-5966-2135 FU NHLBI NIH HHS [R01 HL51286]; NIGMS NIH HHS [R01 GM32125] NR 19 TC 16 Z9 16 U1 0 U2 4 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0952-3480 J9 NMR BIOMED JI NMR Biomed. PD NOV PY 2000 VL 13 IS 7 BP 392 EP 397 DI 10.1002/1099-1492(200011)13:7<392::AID-NBM659>3.0.CO;2-O PG 6 WC Biophysics; Radiology, Nuclear Medicine & Medical Imaging; Spectroscopy SC Biophysics; Radiology, Nuclear Medicine & Medical Imaging; Spectroscopy GA 382NF UT WOS:000165828600003 PM 11114062 ER PT J AU Lopez-Bruna, D Carreras, BA Newman, DE AF Lopez-Bruna, D Carreras, BA Newman, DE TI Effect of power deposition and current evolution on the formation of internal transport barriers SO NUCLEAR FUSION LA English DT Article ID TOKAMAK ENERGY CONFINEMENT; POLOIDAL ROTATION; SHEAR DISCHARGES; CURRENT DRIVE; L-MODE; PLASMAS; SIMULATIONS; TRANSITION; TURBULENCE; DYNAMICS AB A model for internal transport barrier formation in tokamak plasmas [Newman et al., Phys. Plasmas 5 (1998) 938] is extended to include the evolution equation of the plasma current and a model of neutral beam injection power/particle deposition. The envelope density fluctuation level is evolved in time and coupled, via the E x B shearing rate, to the ASTRA system of transport equations. As a practical realization of the model, reversed shear configurations in the TFTR tokamak are studied. It is found that, aside from the total input power, the detailed profiles of power deposition and current density play an essential role in the determination of the value of the transition power threshold. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Alaska Fairbanks, Fairbanks, AK USA. RP Lopez-Bruna, D (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Lopez Bruna, Daniel/L-6539-2014 NR 37 TC 3 Z9 3 U1 0 U2 1 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5, PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD NOV PY 2000 VL 40 IS 11 BP 1825 EP 1838 DI 10.1088/0029-5515/40/11/302 PG 14 WC Physics, Fluids & Plasmas SC Physics GA 374JX UT WOS:000165343000002 ER PT J AU Gao, QD Budny, RV Zhang, JH Li, FZ Jiao, YM AF Gao, QD Budny, RV Zhang, JH Li, FZ Jiao, YM TI Sustained reversed magnetic shear mode of operation in the HL-2A tokamak SO NUCLEAR FUSION LA English DT Article ID NEGATIVE CENTRAL SHEAR; ENHANCED CONFINEMENT; DISCHARGES; TRANSPORT; BETA; PERFORMANCE; STABILITY; PLASMAS; UPGRADE; TFTR AB Realistic reversed magnetic shear (RS) discharges for the HL-PA tokamak are simulated with the TRANSP code. Early NBI heating achieves reversed shear (RS) configurations characterized by highly peaked pressure profiles and a narrow shear reversal region. To avoid excessive peaks in the pressure, and to sustain RS operation towards steady state, LHCD is used to control the current profile. The combined LH and bootstrap current create a quasi-stationary RS discharge with r(min)/a approximate to 0.6 and q(min) approximate to 2.8. A self-consistent internal transport barrier is produced, and the RS configuration is established with a wider shear reversal region and broader pressure profile that is favourable to achieving the high beta limit. C1 SW Inst Phys, Chengdu, Peoples R China. Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08544 USA. RP Gao, QD (reprint author), SW Inst Phys, Chengdu, Peoples R China. NR 32 TC 12 Z9 13 U1 1 U2 5 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5, PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD NOV PY 2000 VL 40 IS 11 BP 1897 EP 1907 DI 10.1088/0029-5515/40/11/309 PG 11 WC Physics, Fluids & Plasmas SC Physics GA 374JX UT WOS:000165343000009 ER PT J AU Anderson, TS Magruder, RH Wittig, JE Kinser, DL Zuhr, RA AF Anderson, TS Magruder, RH Wittig, JE Kinser, DL Zuhr, RA TI Fabrication of Cu-coated Ag nanocrystals in silica by sequential ion implantation SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Letter ID HIGH-PURITY SILICA; METAL COLLOIDS; GLASS; SB AB Metal nanocrystal glass composites were fabricated by single and sequential element implantations of Ag+ and Cu+ ions into high purity silica. Implantation doses (x10(16) ions/cm(2)) were 3Ag, 9Cu and 3Ag/9Cu. Composites were analyzed using Rutherford backscattering techniques (RBS), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and optical spectroscopy. An optical density spectrum based on the size distribution observed in the sequentially implanted sample for Cu shell and Ag core nanocrystals has been calculated using the dipole and quadrupole terms in a Mie series summation and is compared with the observed absorption spectrum. Results from TEM and EDS as well as the optical simulations demonstrate that Cu shell and Ag core nanocrystals are formed by the sequential implantation of Ag and Cu. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Belmont Univ, Dept Phys, Nashville, TN 37212 USA. Booz Allen & Hamilton Inc, Mclean, VA 22102 USA. Vanderbilt Univ, Mat Sci Program, Nashville, TN 37235 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Magruder, RH (reprint author), Belmont Univ, Dept Phys, Nashville, TN 37212 USA. EM magruderr@mail.belmont.edu NR 20 TC 34 Z9 41 U1 1 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X EI 1872-9584 J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD NOV PY 2000 VL 171 IS 3 BP 401 EP 405 DI 10.1016/S0168-583X(00)00369-4 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 372BJ UT WOS:000165213500016 ER PT J AU Kennel, SJ Mirzadeh, S Hurst, GB Foote, LJ Lankford, TK Glowienka, KA Chappell, LL Kelso, JR Davern, SM Safavy, A Brechbiel, MW AF Kennel, SJ Mirzadeh, S Hurst, GB Foote, LJ Lankford, TK Glowienka, KA Chappell, LL Kelso, JR Davern, SM Safavy, A Brechbiel, MW TI Labeling and distribution of linear peptides identified using in vivo phage display selection for tumors SO NUCLEAR MEDICINE AND BIOLOGY LA English DT Article DE peptides; phage display; tumors; distribution; radioiodination; Bi-213; bifunctional DTPA ligands ID N-SUCCINIMIDYL 3-IODOBENZOATE; ALPHA-PARTICLE EMITTER; IN-VIVO; MONOCLONAL-ANTIBODIES; BOMBESIN ANALOG; GROWTH-FACTOR; LOCALIZATION; RECEPTOR; INVIVO; LUNG AB To develop targeting molecules to be used for vascular targeting of short half lived cc-emitters for radioimmunotherapy, linear peptide phage display libraries were selected in vivo for binding to IC-12 rat tracheal tumors growing in severe combined immune deficient mice. After three rounds of selection, 15 phage clones were analyzed for DNA sequence, and the deduced translation products of cDNA inserts were compared. Three consensus sequences were chosen from three separate experimental selection series and peptides of these sequences with added -gly-gly-tyr were obtained. Peptides were radiolabeled on tyrosine with I-125 and the biodistribution in tumor-bearing mice was determined. The radioiodinated peptides were stable in vitro and when injected in tumor-bearing mice similar to3.0 %ID/g accumulated in the tumor; however, much of the I-125 was found in the gastrointestinal tract and thyroid, indicative of dehalogenation of the Labeled peptide. Radiolabeling peptide 2 with N-succinimidyl-3-I-125-iodobenzoate resulted in faster excretion, which in turn resulted in lower levels in tumor and other organs, especially thyroid and gastrointestinal tract. Peptide 2 was derivatized with the bifunctional isothiocyanates of cyclohexyl-B diethylenetriaminepentaacetic acid (DTPA) or CHX-A" DTPA by direct conjugation or with a hydroxylamine derivative of 1B4M-DTPA (2-(p[O-(carboxamylmethyl)hydroxylamine]benzyl)-6-methyl-diethylenetriamine-N,N,N',N",N"-pentaacetic acid ) coupled at the N terminus. The primary molecular species in the conjugated products were shown by mass spectrometry to have one DTPA per peptide. Peptide chelate conjugates were radiolabeled with Bi-213 and the products tested for biodistribution in tumor bearing mice. The data show that chelation of Bi-213 to peptides was accomplished by both the direct method of DTPA attachment and by the method using the linker at the N-terminus, Only small amounts of peptide accumulated at tumor sites. We conclude that phage display is a powerful tool to select peptides with restricted binding specificity; however, the peptides isolated to date do not bind with high retention to tumor sites in vivo. NUCL IVIED BIOL 27;8: 815-825, 2000. (C) 2000 Elsevier Science Inc. All rights reserved. C1 Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. NCI, Chem Sect, ROB, DCS,NIH, Bethesda, MD USA. Univ Alabama, Dept Radiat Oncol, Birmingham, AL USA. RP Kennel, SJ (reprint author), Oak Ridge Natl Lab, Div Life Sci, Bldg 4500S,Rm F150, Oak Ridge, TN 37831 USA. NR 46 TC 24 Z9 27 U1 2 U2 7 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0969-8051 J9 NUCL MED BIOL JI Nucl. Med. Biol. PD NOV PY 2000 VL 27 IS 8 BP 815 EP 825 DI 10.1016/S0969-8051(00)00149-9 PG 11 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 392VQ UT WOS:000166433600018 PM 11150716 ER PT J AU Booth, TE AF Booth, TE TI Adaptive importance sampling with a rapidly varying importance function SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article ID MONTE-CARLO; VARIANCE AB It is known well that zero-variance Monte Carlo solutions are possible if an exact importance function is available to bias the random walks. Monte Carlo can be used to estimate the importance function. This estimated importance function then can be used to bias a subsequent Monte Carlo calculation that estimates an even better importance function; this iterative process is called adaptive importance sampling. To obtain the importance function, one can expand the importance function in a basis such as the Legendre polynomials and make Monte Carlo estimates of the expansion coefficients. For simple problems, Legendre expansions of order 10 to 15 are able to represent the importance function well enough to reduce the error geometrically by ten orders of magnitude or more. The more complicated problems are addressed in which the importance function cannot be represented well by Legendre expansions of order 10 to 15. In particular, a problem with a cross-section notch and a problem with a discontinuous cross section are considered. C1 Univ Calif Los Alamos Natl Lab, Diagnost Applicat Grp, Los Alamos, NM 87545 USA. RP Booth, TE (reprint author), Univ Calif Los Alamos Natl Lab, Diagnost Applicat Grp, Mail Stop F663,X-5, Los Alamos, NM 87545 USA. NR 4 TC 8 Z9 9 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0029-5639 J9 NUCL SCI ENG JI Nucl. Sci. Eng. PD NOV PY 2000 VL 136 IS 3 BP 399 EP 408 PG 10 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 368XQ UT WOS:000090143100007 ER PT J AU Galperin, A Segev, M Todosow, M AF Galperin, A Segev, M Todosow, M TI A pressurized water reactor plutonium incinerator based on thorium fuel and seed-blanket assembly geometry SO NUCLEAR TECHNOLOGY LA English DT Article AB A pressurized water reactor (PWR)fuel cycle is proposed, whose purpose is the elimination and degradation of weapons-grade plutonium. This Radkowsky thorium-fuel Po incinerator(RTPI) cycle is based on a core and assemblies retrofittable to a Westinghouse-type PWR. The RTPI assembly: however. is a seed-blanket unit. The seed is supercritical, loaded with Pu-Zr alloy as fuel in a high moderator-to-fuel ratio configuration. The blanket is subcritical, loaded mainly with ThO2, generating and burning U-233 in situ. Blankets are loaded once every 6 yr. The seed fuel management scheme is based on three hatches, with one-third of the seed modules replaced every year. The core generates 1100 MW(electric). Equilibrium conditions are achieved with the second seed lending. For equilibrium conditions, the annual average of disposed (loaded) Po is 1210 kg, of which 702 kg are completely eliminated, and 508 kg are discharged but with significantly degraded isotopics (i.e., with a high percentage of even mass isotopes). Spontaneous fissions per second in a gram of this degraded Pu are similar to 500 resulting ill significantly increased proliferation resistance, Every 6 yr the blanket discharge contains 780 kg of U-233 (including Pa-233) and 36 kg of U-235. However, the blankets are initially loaded,with all amount of natural uranium selected such that these U fissile isotopes constitute only 12% of the total U discharge, a percentage equivalent to 20% U-235 enrichment; hence, both the discharged uranium isotopics satisfy proliferation-resistant criteria. The RTPI control variables, namely, the moderator temperature coefficient, the reactivity per ppm boron, and the control rods worth, are about equal to those of a PWR. The RTPI spent-fuel stockpile ingestion toxicity over a period often million years is about the same as the counterpart toxicities of a regular, or a mixed-oxide (MOX), PWR. Compared with known PWR MOX variants, the RTPI is, per 1000 MW(electric) and per annum, a significantly more efficient incinerator of weapons-grade plutonium. C1 Ben Gurion Univ Negev, Dept Nucl Engn, IL-84105 Beer Sheva, Israel. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Galperin, A (reprint author), Ben Gurion Univ Negev, Dept Nucl Engn, 1 Bar Kochua St, IL-84105 Beer Sheva, Israel. NR 8 TC 14 Z9 14 U1 1 U2 2 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD NOV PY 2000 VL 132 IS 2 BP 214 EP 226 PG 13 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 364UQ UT WOS:000089911700004 ER PT J AU Jimenez-Garate, MA Craig, WW Hailey, CJ Christensen, FE Hussain, A AF Jimenez-Garate, MA Craig, WW Hailey, CJ Christensen, FE Hussain, A TI Fabrication, performance, and figure metrology of epoxy-replicated aluminum foils for hard x-ray focusing multilayer-coated segmented conical optics SO OPTICAL ENGINEERING LA English DT Article DE x-rays; metrology; mirrors; grazing incidence; space optics ID CONSTELLATION-X; GAMMA-SATELLITE; TELESCOPE HEFT; MIRROR MODULES; SUPERMIRROR; SURFACES; SCATTER AB We fabricated x-ray mirrors for hard x-ray (greater than or equal to 10 keV) telescopes using multilayer coatings and an improved epoxy-replicated aluminum foil (ERAF) nonvacuum technology. The ERAF optics have similar to1 arcmin axial figure half-power diameter (HPD) and passed environmental testing. Reflectivity measurements at 8 keV on ERAFs with and without multilayer coatings show a 4.4 to 4.8 A root mean square (rms) microroughness for correlation lengths less than or equal to 15 mum. To reduce the dominant contribution of mirror assembly and large-scale distortion in the overall telescope HPD, we designed a figure metrology system and a new mounting technique. We describe a cylindrical metrology system built for fast axial and roundness figure measurement of hard x-ray conical optics. These developments lower cost and improve the optics performance of the HEFT (high-energy focusing telescope) and Constellation-X missions. (C) 2000 society of Photo-Optical Instrumentation Engineers. [S0091-3286(00)01611-1]. C1 Columbia Univ, Astrophys Lab, New York, NY 10027 USA. Danish Space Res Inst, Copenhagen, Denmark. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Jimenez-Garate, MA (reprint author), Columbia Univ, Astrophys Lab, 538 W 120th St, New York, NY 10027 USA. NR 42 TC 11 Z9 11 U1 0 U2 0 PU SPIE-INT SOCIETY OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD NOV PY 2000 VL 39 IS 11 BP 2982 EP 2994 DI 10.1117/1.1315572 PG 13 WC Optics SC Optics GA 376WH UT WOS:000165479400020 ER PT J AU Jellison, GE Boatner, LA Chen, C AF Jellison, GE Boatner, LA Chen, C TI Spectroscopic refractive indices of metalorthophosphates with the zircon-type structure SO OPTICAL MATERIALS LA English DT Article DE rare earths; orthophosphates; refractive index; ellipsometry ID 2-MODULATOR GENERALIZED ELLIPSOMETRY; DOPED LUTETIUM ORTHOPHOSPHATE; OPTICAL FUNCTIONS; ORTHO-PHOSPHATES; YBPO4 AB The spectroscopic refractive indices for nine zircon-structure orthophosphate compounds (LnPO(4), where Ln = Sc, Y, Tb, Dy, Ho, Er, Tm, Yb, and Lu) have been determined from 270 to 850 nm (1.46-4.59 eV) using two-modulator generalized ellipsometry. All crystals are highly birefringent, where Delta n = n(o) - n(e) similar to 0.18-0.22. All refractive indices are dispersive with wavelength, and can be fit with a single-term Sellmeier model. The refractive indices of the seven rare-earth orthophosphates (Ln = Tb, Dy, Ho, Er, Tm, Yb, and Lu) were the same within the error limits of the measurement, but the refractive indices of ScPO4 and YPO4 were larger and smaller, respectively, than the refractive indices of the rare-earth orthophosphates. These results are pertinent to current studies of the use of orthophosphates as laser hosts, scintillators, and thermophosphors. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Penn State Univ, State Coll, PA USA. RP Jellison, GE (reprint author), Oak Ridge Natl Lab, Div Solid State, MS-6030,Bldg 3025, Oak Ridge, TN 37831 USA. RI Boatner, Lynn/I-6428-2013 OI Boatner, Lynn/0000-0002-0235-7594 NR 21 TC 17 Z9 17 U1 2 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0925-3467 J9 OPT MATER JI Opt. Mater. PD NOV PY 2000 VL 15 IS 2 BP 103 EP 109 DI 10.1016/S0925-3467(00)00027-6 PG 7 WC Materials Science, Multidisciplinary; Optics SC Materials Science; Optics GA 355KR UT WOS:000089385300003 ER PT J AU Biswas, R Hendrickson, B Karypis, G AF Biswas, R Hendrickson, B Karypis, G TI Graph partitioning and parallel computing SO PARALLEL COMPUTING LA English DT Editorial Material C1 NASA, Ames Res Ctr, MRJ Technol Solut, Moffett Field, CA 94035 USA. Sandia Natl Labs, Parallel Comp Sci Dept, Albuquerque, NM 87185 USA. Univ Minnesota, Dept Comp Sci, Minneapolis, MN 55455 USA. RP Biswas, R (reprint author), NASA, Ames Res Ctr, MRJ Technol Solut, MS T27A-1, Moffett Field, CA 94035 USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-8191 J9 PARALLEL COMPUT JI Parallel Comput. PD NOV PY 2000 VL 26 IS 12 BP 1515 EP 1517 DI 10.1016/S0167-8191(00)00042-9 PG 3 WC Computer Science, Theory & Methods SC Computer Science GA 362LL UT WOS:000089779400001 ER PT J AU Hendrickson, B Kolda, TG AF Hendrickson, B Kolda, TG TI Graph partitioning models for parallel computing SO PARALLEL COMPUTING LA English DT Article DE graph partitioning; hypergraph partitioning; parallel computing ID COMPUTATIONS; DECOMPOSITION AB Calculations can naturally be described as graphs in which vertices represent computation and edges reflect data dependencies. By partitioning the vertices of a graph, the calculation can be divided among processors of a parallel computer. However, the standard methodology for graph partitioning minimizes the wrong metric and lacks expressibility. We survey several recently proposed alternatives and discuss their relative merits. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Sandia Natl Labs, Parallel Comp Sci Dept, Albuquerque, NM 87185 USA. Sandia Natl Labs, Computat Sci & Math Res Dept, Livermore, CA 94551 USA. RP Sandia Natl Labs, Parallel Comp Sci Dept, POB 5800, Albuquerque, NM 87185 USA. EM bah@cs.sandia.gov; tgkolda@sandia.gov RI Kolda, Tamara/B-1628-2009 OI Kolda, Tamara/0000-0003-4176-2493 NR 33 TC 136 Z9 145 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-8191 EI 1872-7336 J9 PARALLEL COMPUT JI Parallel Comput. PD NOV PY 2000 VL 26 IS 12 BP 1519 EP 1534 DI 10.1016/S0167-8191(00)00048-X PG 16 WC Computer Science, Theory & Methods SC Computer Science GA 362LL UT WOS:000089779400002 ER PT J AU Oliker, L Biswas, R Gabow, HN AF Oliker, L Biswas, R Gabow, HN TI Parallel tetrahedral mesh adaptation with dynamic load balancing SO PARALLEL COMPUTING LA English DT Article DE unstructured-meshes; graph repartitioning; data remapping; redistribution cost metrics; portability analysis ID ADAPTIVE UNSTRUCTURED MESHES; CONSERVATION-LAWS; ALGORITHMS; GRIDS; COMPUTATIONS; MODEL AB The ability to dynamically adapt an unstructured-grid is a powerful tool for efficiently solving computational problems with evolving physical features. In this paper, we report on our experience parallelizing an edge-based adaptation scheme, called 3D_TAG, using message passing. Results show excellent speedup when a realistic helicopter rotor mesh is randomly refined. However, performance deteriorates when the mesh is refined using a solution-based error indicator since mesh adaptation for practical problems occurs in a localized region, creating a severe load imbalance. To address this problem, we have developed PLUM, a global dynamic load balancing framework for adaptive numerical computations. Even though PLUM primarily balances processor workloads for the solution phase, it reduces the load imbalance problem within mesh adaptation by repartitioning the mesh after targeting edges for refinement but before the actual subdivision. This dramatically improves the performance of parallel 3D_TAG since refinement occurs in a more load balanced fashion. We also present optimal and heuristic algorithms that, when applied to the default mapping of a parallel repartitioner, significantly reduce the data redistribution overhead. Finally, portability is examined by comparing performance on three state-of-the-art parallel machines, (C) 2000 Elsevier Science B.V. All rights reserved. C1 NASA, Ames Res Ctr, MRJ Technol Solut, Moffett Field, CA 94035 USA. Univ Colorado, Dept Comp Sci, Boulder, CO 80309 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, NERSC, Berkeley, CA 94720 USA. RP Biswas, R (reprint author), NASA, Ames Res Ctr, MRJ Technol Solut, MS T27 A-1, Moffett Field, CA 94035 USA. EM loliker@lbl.gov; rbiswas@nas.nasa.gov; hal@piper.cs.colorado.edu NR 31 TC 24 Z9 24 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-8191 J9 PARALLEL COMPUT JI Parallel Comput. PD NOV PY 2000 VL 26 IS 12 BP 1583 EP 1608 DI 10.1016/S0167-8191(00)00047-8 PG 26 WC Computer Science, Theory & Methods SC Computer Science GA 362LL UT WOS:000089779400005 ER PT J AU Sago, H Carlson, EJ Smith, DJ Rubin, EM Crnic, LS Huang, TT Epstein, CJ AF Sago, H Carlson, EJ Smith, DJ Rubin, EM Crnic, LS Huang, TT Epstein, CJ TI Genetic dissection of region associated with behavioral abnormalities in mouse models for Down syndrome SO PEDIATRIC RESEARCH LA English DT Article ID TS65DN MICE; MUTATIONS; DEFICITS; MEMORY AB Two animal models of Down syndrome (human trisomy 21) with segmental trisomy for ail (Ts65Dn) or part (Ts1Cje) of human chromosome 21-homologous region of mouse chromosome 16 have cognitive: and behavioral abnormalities. To compare these trisomies directly and to assess the phenotypic contribution of the region of difference between them, Ts65Dn, Ts1Cje, and a new segmental trisomic (Ms1Ts65) for the region of difference (App to Sod1) have been generated as Littermates and tested in parallel. Although the performance of Ts1Cje mice in the Morris water maze is similar to that of Ts65Dn mice, the reverse probe tests indicate that Ts65Dn is more severely affected. By contrast, the deficits of Ms1Ts65 mice are significantly less severe than those of Ts65Dn. Therefore, whereas triplication of Sod1 to Mx1 plays the major role in causing the abnormalities of Ts65Dn in the Morris water maze, imbalance of App to Sod1 also contributes to the poor performance. Ts65Dn mice are hyperactive and Ts1Cje mice are hypoactive; the activity of Ms1Ts65 mice is not significantly above normal. These findings indicate that genes in the Ms1Ts65 trisomic legion must interact with others in the Ts1Cje region to produce hyperactivity in Ts65Dn mice. C1 Univ Calif San Francisco, Dept Pediat, San Francisco, CA 94143 USA. Lawrence Berkeley Natl Lab, Ctr Human Genome, Berkeley, CA USA. Univ Colorado, Sch Med, Dept Pediat, Denver, CO USA. Univ Colorado, Sch Med, Dept Psychiat, Denver, CO 80262 USA. Natl Okura Hosp, Tokyo, Japan. RP Epstein, CJ (reprint author), Univ Calif San Francisco, Dept Pediat, Box 0748, San Francisco, CA 94143 USA. FU NIA NIH HHS [AG08938]; NICHD NIH HHS [HD04024, HD17499] NR 19 TC 117 Z9 117 U1 0 U2 2 PU INT PEDIATRIC RESEARCH FOUNDATION, INC PI BALTIMORE PA 351 WEST CAMDEN ST, BALTIMORE, MD 21201-2436 USA SN 0031-3998 J9 PEDIATR RES JI Pediatr. Res. PD NOV PY 2000 VL 48 IS 5 BP 606 EP 613 DI 10.1203/00006450-200011000-00009 PG 8 WC Pediatrics SC Pediatrics GA 367CV UT WOS:000090044900009 PM 11044479 ER PT J AU Chisholm, MF Duscher, G Pang, LX Kumar, KS AF Chisholm, MF Duscher, G Pang, LX Kumar, KS TI Fe16Al14B2 phase in Fe-Al alloys SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article ID TENSILE PROPERTIES; FAULTS; BORON; ELECTRONS; FE-40 AB The atomic structure and composition of a recently reported second phase found in Fe-Al alloys with small B and C additions have been determined using a combination of Z-contrast imaging and electron-energy-loss spectroscopy. The structure of this ordered tetragonal precipitate is found to be closely related to the B2 structure of the matrix. The derived structure and electron-energy-loss spectroscopy indicate that the phase is a new low-metalloid-content boride with B occupying specific interstitial sites. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Brown Univ, Div Engn, Providence, RI 02912 USA. RP Chisholm, MF (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. RI Duscher, Gerd/G-1730-2014 OI Duscher, Gerd/0000-0002-2039-548X NR 17 TC 4 Z9 4 U1 0 U2 2 PU TAYLOR & FRANCIS LTD PI LONDON PA 11 NEW FETTER LANE, LONDON EC4P 4EE, ENGLAND SN 0141-8610 J9 PHILOS MAG A JI Philos. Mag. A-Phys. Condens. Matter Struct. Defect Mech. Prop. PD NOV PY 2000 VL 80 IS 11 BP 2737 EP 2745 PG 9 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA 374CM UT WOS:000165326900017 ER PT J AU Lawson, AC Martinez, B Von Dreele, RB Roberts, JA Sheldon, RI Brun, TO Richardson, JW AF Lawson, AC Martinez, B Von Dreele, RB Roberts, JA Sheldon, RI Brun, TO Richardson, JW TI Vibrational order in Pu0.98Ga0.02 SO PHILOSOPHICAL MAGAZINE B-PHYSICS OF CONDENSED MATTER STATISTICAL MECHANICS ELECTRONIC OPTICAL AND MAGNETIC PROPERTIES LA English DT Article ID DIFFRACTION; SCATTERING; DISORDER; LEAD AB In an earlier paper (Lawson et al., 2000, Phil. Mag. B, 80, 53) we described the measurement and interpretation of Debye-Waller factors in a delta -phase Pu0.98Ga0.02 alloy. We concluded that the measurements could be described using a Debye model with a strongly temperature-dependent Debye-Waller temperature. In those experiments, we observed significant diffuse scattering in the neutron powder diffraction patterns. In this paper we describe a new technique for analysing diffuse scattering based on Rietveld analysis, and apply the technique to data for F-phase Pu0.98Ga0.02 and for Pb. The results from the correlations among lattice vibrations show that the diffuse scattering is Warren-Borie scattering and that the diffuse scattering is in basic agreement with that expected from the Debye model except that the scattering from the nearest-neighbour correlations in Pu0.98Ga0.02 is anomalous at high temperatures. We also discuss the observation of significant anisotropic broadening of the diffraction peaks for Pu0.98Ga0.02 at low temperatures. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP Lawson, AC (reprint author), Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. EM lawson@lanl.gov NR 29 TC 14 Z9 15 U1 1 U2 7 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0141-8637 J9 PHILOS MAG B JI Philos. Mag. B-Phys. Condens. Matter Stat. Mech. Electron. Opt. Magn. Prop. PD NOV PY 2000 VL 80 IS 11 BP 1869 EP 1891 DI 10.1080/13642810008216511 PG 23 WC Materials Science, Multidisciplinary; Mechanics; Physics, Applied; Physics, Condensed Matter SC Materials Science; Mechanics; Physics GA 374CR UT WOS:000165327300001 ER PT J AU Hochbauer, T Misra, A Verda, R Nastasi, M Mayer, JW Zheng, Y Lau, SS AF Hochbauer, T Misra, A Verda, R Nastasi, M Mayer, JW Zheng, Y Lau, SS TI Hydrogen-implantation induced silicon surface layer exfoliation SO PHILOSOPHICAL MAGAZINE B-PHYSICS OF CONDENSED MATTER STATISTICAL MECHANICS ELECTRONIC OPTICAL AND MAGNETIC PROPERTIES LA English DT Article ID STRESS; SI AB The physical mechanisms of hydrogen-induced silicon surface cleavage were investigated using the combination of cross section transmission electron microscopy (XTEM) and Rutherford back-scattering spectrometry (RBS) channelling analysis. A [100]-oriented silicon wafer was implanted with 175 keV protons to a dose of 5 x 10(16) cm(-2). The implanted wafer was bonded to a SiO2-capped [100]-oriented silicon wafer and then heated to an elevated temperature of 600 degreesC to produce exfoliation. The damage region of the implanted silicon was examined by XTEM, which revealed the presence of hydrogen-filled platelets. The depth distribution of the implantation damage was also monitored by RES in the channelling condition in the as-implanted state as well as after the cleavage of the silicon wafer. A comparison of the RES and XTEM indicates that the nucleation of hydrogen-filled microcavities and the cleavage of the silicon wafer take place above the hydrogen concentration peak near the implantation damage peak, revealing the crucial role of the implantation damage in the crystal in terms of hydrogen-induced silicon surface layer exfoliation. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Arizona State Univ, Tempe, AZ 85287 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. RP Hochbauer, T (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Misra, Amit/H-1087-2012 NR 24 TC 13 Z9 16 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI LONDON PA 11 NEW FETTER LANE, LONDON EC4P 4EE, ENGLAND SN 0141-8637 J9 PHILOS MAG B JI Philos. Mag. B-Phys. Condens. Matter Stat. Mech. Electron. Opt. Magn. Prop. PD NOV PY 2000 VL 80 IS 11 BP 1921 EP 1931 DI 10.1080/13642810008216514 PG 11 WC Materials Science, Multidisciplinary; Mechanics; Physics, Applied; Physics, Condensed Matter SC Materials Science; Mechanics; Physics GA 374CR UT WOS:000165327300004 ER PT J AU Li, FX Lu, P Ishimaru, M Sickafus, KE AF Li, FX Lu, P Ishimaru, M Sickafus, KE TI Effect of heavy ion irradiation on near-surface microstructure in single crystals of rutile TiO2 SO PHILOSOPHICAL MAGAZINE B-PHYSICS OF CONDENSED MATTER STATISTICAL MECHANICS ELECTRONIC OPTICAL AND MAGNETIC PROPERTIES LA English DT Article ID LATTICE DISORDER; IMPLANTED TIO2; RECOVERY; UO2 AB Radiation damage near the surface of rutile (TiO2) single crystals irradiated with 360keV Xe2+ ions has been studied by combining Rutherford backscattering spectroscopy and ion channelling (RBS/C) analyses with direct observations using transmission electron microscopy (TEM). Irradiations were performed at ambient temperature on TiO2 single crystal surfaces with (110) and (100) orientations, using ion fluences of up to 7 x 10(19) Xe ions m(-2). The RBS/C spectra revealed two damage peaks: one peak due to a surface damage layer and a second peak due to a buried damage layer near the mean projected range of the implanted ions. Cross-sectional TEM and high-resolution electron microscopy revealed that the surface damage layer consists of TiO2 crystallites with different orientations compared with the original single crystal. C1 New Mexico Inst Min & Technol, Socorro, NM 87801 USA. Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. Osaka Univ, Inst Sci & Ind Res, Ibaraki, Osaka 5670047, Japan. RP Sickafus, KE (reprint author), New Mexico Inst Min & Technol, Socorro, NM 87801 USA. NR 14 TC 6 Z9 6 U1 0 U2 4 PU TAYLOR & FRANCIS LTD PI LONDON PA 11 NEW FETTER LANE, LONDON EC4P 4EE, ENGLAND SN 0141-8637 J9 PHILOS MAG B JI Philos. Mag. B-Phys. Condens. Matter Stat. Mech. Electron. Opt. Magn. Prop. PD NOV PY 2000 VL 80 IS 11 BP 1947 EP 1954 DI 10.1080/13642810008216517 PG 8 WC Materials Science, Multidisciplinary; Mechanics; Physics, Applied; Physics, Condensed Matter SC Materials Science; Mechanics; Physics GA 374CR UT WOS:000165327300007 ER PT J AU Bussmann-Holder, A Simon, A Buttner, H Bishop, AR AF Bussmann-Holder, A Simon, A Buttner, H Bishop, AR TI Phonon induced stripe formation and charge ordering in high-T(c) superconductors SO PHILOSOPHICAL MAGAZINE B-PHYSICS OF CONDENSED MATTER STATISTICAL MECHANICS ELECTRONIC OPTICAL AND MAGNETIC PROPERTIES LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTORS; HUBBARD-MODEL; PEIERLS; FLUCTUATIONS; SOLITONS; POLARON; SYSTEMS AB Two recent experimental findings on the formation of stripes in high-temperature superconductors show that substantial lattice effects are involved in the onset of stripe formation. Huge phonon anomalies have been observed at finite q-vector where this q-value correlates with doping. In addition, a giant isotope effect on the onset temperature T* for stripe formation has been reported recently. We show here that the striped phase can be caused by a strong nonlinear electron-phonon interaction which yields dynamical charge ordering on a mesoscale length scale and in a limited time range. A large isotope effect on T* is obtained together with substantial phonon anomalies. C1 Max Planck Inst Festkorperforsch, D-70569 Stuttgart, Germany. Univ Bayreuth, Lehrstuhl Theoret Phys 1, D-95440 Bayreuth, Germany. Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Bussmann-Holder, A (reprint author), Max Planck Inst Festkorperforsch, Heisenbergstr 1, D-70569 Stuttgart, Germany. EM annet@sim.mpi-stuttgart.mpg.de NR 20 TC 17 Z9 17 U1 1 U2 2 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0141-8637 J9 PHILOS MAG B JI Philos. Mag. B-Phys. Condens. Matter Stat. Mech. Electron. Opt. Magn. Prop. PD NOV PY 2000 VL 80 IS 11 BP 1955 EP 1960 DI 10.1080/13642810008216518 PG 6 WC Materials Science, Multidisciplinary; Mechanics; Physics, Applied; Physics, Condensed Matter SC Materials Science; Mechanics; Physics GA 374CR UT WOS:000165327300008 ER PT J AU Pant, V Goodrich, RG Godbole, MG Lowndes, DH AF Pant, V Goodrich, RG Godbole, MG Lowndes, DH TI Radiofrequency impedance measurements at 2 MHz on YBa2Cu3O7 epitaxial films SO PHILOSOPHICAL MAGAZINE B-PHYSICS OF CONDENSED MATTER STATISTICAL MECHANICS ELECTRONIC OPTICAL AND MAGNETIC PROPERTIES LA English DT Article ID KOSTERLITZ-THOULESS TRANSITION; SINGLE-CRYSTALS; SUPERCONDUCTING YBA2CU3O7-DELTA; 2-DIMENSIONAL SUPERFLUIDS; PENETRATION DEPTH; THIN-FILMS; SUPERLATTICES; FLUCTUATIONS; TEMPERATURE; RESISTANCE AB Measurements of the temperature dependence of the rf electrical impedance of YBa2Cu3O7 epitaxial films of 0.25, 0.5 and 1.0 mum thickness are reported. The contactless 2 MHz ac measurements yield both the real and the imaginary parts of the impedance. The temperature dependence of the real part of the impedance shows a peak in the resistance just below T-c for all the sample thicknesses, and we interpret this as being due to a Kosterlitz-Thouless (K-T) transition. The imaginary part gives the change in the kinetic inductance. From an analysis of the data near the K-T transition temperature an effective superconducting thickness of the sample is determined. C1 Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA. EM goodrich@lsu.phys.edu NR 29 TC 0 Z9 0 U1 1 U2 1 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 2-4 PARK SQUARE, MILTON PARK, ABINGDON OR14 4RN, OXON, ENGLAND SN 0141-8637 J9 PHILOS MAG B JI Philos. Mag. B-Phys. Condens. Matter Stat. Mech. Electron. Opt. Magn. Prop. PD NOV PY 2000 VL 80 IS 11 BP 1961 EP 1974 DI 10.1080/13642810008216519 PG 14 WC Materials Science, Multidisciplinary; Mechanics; Physics, Applied; Physics, Condensed Matter SC Materials Science; Mechanics; Physics GA 374CR UT WOS:000165327300009 ER PT J AU Ciftja, O AF Ciftja, O TI Spin correlation functions of some frustrated ultra-small classical Heisenberg clusters SO PHYSICA A LA English DT Article DE classical spin; Heisenberg model; molecular magnet ID SUSCEPTIBILITY; COMPLEXES AB We obtain analytical expressions for the spin correlation functions and zero-field susceptibility of small clusters of classical Heisenberg spins. The clusters consist of three, four and five spins interacting with antiferromagnetic exchange interaction where the exchange interaction between one of the spins and the other spins may be different from the n-n exchange between the remaining spins placed in a ring. These systems provide a useful theoretical framework for calculating the magnetic properties of several recently synthesized molecular magnets. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. RP Ciftja, O (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 12 TC 9 Z9 9 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4371 J9 PHYSICA A JI Physica A PD NOV 1 PY 2000 VL 286 IS 3-4 BP 541 EP 557 DI 10.1016/S0378-4371(00)00326-5 PG 17 WC Physics, Multidisciplinary SC Physics GA 364XV UT WOS:000089920100011 ER PT J AU Chu, CW AF Chu, CW TI High temperature superconducting materials: Present status, future challenges, and one recent example-the superconducting ferromagnet SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID SPONTANEOUS VORTEX PHASE; COEXISTENCE; RUSR2GDCU2O8; DENSITY AB Great progress has been made in all areas of high temperature superconductivity research in the last 14 years. This presentation will focus only on the material aspects. After briefly summarizing the present status and future challenges, some characteristics of ideal high temperature superconductors are proposed. High temperature superconductors also provide a fertile ground for the study of physics. This is exemplified by the recent observation of a novel superconducting state in the superconducting ferromagnet RuSr2GdCu2O8. C1 Univ Houston, Dept Phys, Houston, TX 77204 USA. Univ Houston, Texas Ctr Superconduct, Houston, TX 77204 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Chu, CW (reprint author), Univ Houston, Dept Phys, Houston, TX 77204 USA. NR 31 TC 11 Z9 11 U1 2 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 25 EP 30 DI 10.1016/S0921-4534(00)00381-6 PN 1 PG 6 WC Physics, Applied SC Physics GA 382YT UT WOS:000165855500007 ER PT J AU Pines, D AF Pines, D TI Quantum protectorates in the cuprate superconductors SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID NORMAL-STATE; YBA2CU3O7 AB Following the identification of the pairing state, the major challenge in understanding the cuprate superconductors has been determining the evolution with doping and temperature of their anomalous normal state behavior. Key to this understanding is the experimentally determined magnetic phase diagram for the cuprates, which provides information on the protected magnetic properties of the normal state, generic behavior that is reliably the same one system to the next, regardless of details. I discuss the constraints this places on candidate quantum protectorates, and the status of microscopic model calculations for a protectorate consistent with these constraints, the nearly antiferromagnetic Fermi liquid. C1 Univ Calif Los Alamos Natl Lab, Off President, LANSCE Div, Inst Complex Adapt Matter, Los Alamos, NM 87545 USA. Univ Illinois, Sci & Technol Ctr Superconduct, Chicago, IL 60680 USA. RP Pines, D (reprint author), Univ Calif Los Alamos Natl Lab, Off President, LANSCE Div, Inst Complex Adapt Matter, Los Alamos, NM 87545 USA. NR 12 TC 22 Z9 22 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 NOV PY 2000 VL 341 BP 59 EP 62 DI 10.1016/S0921-4534(00)00389-0 PN 1 PG 4 WC Physics, Applied SC Physics GA 382YT UT WOS:000165855500013 ER PT J AU Abrikosov, AA AF Abrikosov, AA TI Theory of high-Tc superconducting cuprates based on experimental evidence SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID HIGH-TEMPERATURE SUPERCONDUCTORS; SADDLE-POINT MODEL; UPPER CRITICAL-FIELD; ORDER-PARAMETER; ISOTOPE; YBA2CU3O7-DELTA; SINGULARITY; YBA2CU4O8; PARITY AB A model of superconductivity in layered high-temperature superconducting cuprates is proposed, based on the extended saddle point singularities ill the electron spectrum, weak screening of the Coulomb interaction and phonon-mediated interaction between electrons plus a small short range repulsion of Hund's, or spin-fluctuation, origin. This permits to explain the large values of Tc, features of the isotope effect on oxygen and copper, the existence of two types of the order parameter, the peak in the inelastic neutron scattering, the positive curvature of the upper critical field, as function of temperature etc. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Abrikosov, AA (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 25 TC 26 Z9 28 U1 2 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 97 EP 102 DI 10.1016/S0921-4534(00)00399-3 PN 1 PG 6 WC Physics, Applied SC Physics GA 382YT UT WOS:000165855500022 ER PT J AU Kresin, V Ovchinnikov, Y Wolf, S AF Kresin, V Ovchinnikov, Y Wolf, S TI Intrinsic inhomogeneity and the origin of the pseudogap SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID T-C; OVERDOPED BI2SR2CACU2O8+DELTA; SUPERCONDUCTORS; STATE; GAP AB Phenomenon of the pseudogap is caused by an intrinsic inhomogeneity and the dependence T-c(r). Set of superconducting islands (at T>T-c(res)) manifests itself in peculiar magnetic properties as well as in spectroscopy (pseudogap). C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Russian Acad Sci, LD Landau Theoret Phys Inst, Moscow 11733V, Russia. CNRS, F-38042 Grenoble, France. USN, Res Lab, Washington, DC 20375 USA. RP Kresin, V (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 13 TC 7 Z9 7 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 NOV PY 2000 VL 341 BP 103 EP 106 DI 10.1016/S0921-4534(00)00406-8 PN 1 PG 4 WC Physics, Applied SC Physics GA 382YT UT WOS:000165855500023 ER PT J AU Martin, I Balatsky, AV AF Martin, I Balatsky, AV TI Local structure of impurity states in d-wave superconductors SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID PARTICLE AB Scanning Tunneling Microscope (STM) experiments offer a unique insight into the inner workings of the superconducting state of high-Tc superconductors. Deliberately placed inside the material impurities perturb the coherent state and produce additional excitations. Superconducting excitation - quasiparticle - is a quantum-mechanical mixture of a negatively charged electron (-e) and a positively charged hole (+e). Depending on the applied voltage bias in STM one can sample the particle and hole content of a superconducting excitation. We argue that the complementary cross-shaped patterns observed on the positive and negative biases are the manifestation of the particle-hole duality of the quasiparticles. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Martin, I (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 11 TC 3 Z9 3 U1 1 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 NOV PY 2000 VL 341 BP 125 EP 128 DI 10.1016/S0921-4534(00)00412-3 PN 1 PG 4 WC Physics, Applied SC Physics GA 382YT UT WOS:000165855500029 ER PT J AU Shi, FJ AF Shi, FJ TI The possibility of bi-exciton pairing in singlet and in triplet states in cuprate superconductors SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS AB We investigate a spin-pairing mechanism of superconductivity based on a continuous strong-correlation model that we proposed previously. The model shows that substitutional doping may generate an quasi-exciton, a hole-dopant pair with immobile dopant. Two excitons interact with each other, resulting in two spin-pairing eigen states - the singlet and triplet states. A condensed phase of N excitons is proved to be a Gutzwiller projection of a Bose condensation. C1 Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Shi, FJ (reprint author), Lawrence Berkeley Lab, Div Mat Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 3 TC 0 Z9 0 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 NOV PY 2000 VL 341 BP 311 EP 312 DI 10.1016/S0921-4534(00)00495-0 PN 1 PG 2 WC Physics, Applied SC Physics GA 382YT UT WOS:000165855500112 ER PT J AU Suh, BJ Borsa, F Jang, ZH Yi, Z Lee, SI AF Suh, BJ Borsa, F Jang, ZH Yi, Z Lee, SI TI La-139 and Cu-63 NQR in Zn-doped lanthanum cuprate SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID NEUTRON-SCATTERING; PHASE-DIAGRAM; LA2-XSRXCUO4; TEMPERATURE; SUPERCONDUCTIVITY; TRANSITION; ORDER; HOLES; SPINS AB La-139 and Cu-63 nuclear quadrupole resonance (NQR) relaxation measurements have been performed in a series of La1.87Sr0.13Cu1-yZnyO4 (0 less than or equal to y less than or equal to 0.03) samples which show a dramatic suppression of the superconducting transition with Zn doping. La-139 T-139(1)-1 exhibits an enhancement at low T similar to the spin glass behavior in other lanthanum cuprates, but the peak indicating spin freezing is not observed down to 4.2 K. The opening of spin pseudogap is found to be suppressed as T-c decreases. These results appear to be associated with a disordered state of pinned charge stripes. C1 Catholic Univ Korea, Dept Phys, Puchon 420743, South Korea. Iowa State Univ, Dept Phys, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Pohang Univ Sci & Technol, Dept Phys, Pohang 790390, South Korea. Pohang Univ Sci & Technol, Natl Creat Res Initiat Ctr Supercond, Pohang 790390, South Korea. RP Suh, BJ (reprint author), Catholic Univ Korea, Dept Phys, Puchon 420743, South Korea. NR 16 TC 0 Z9 0 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 NOV PY 2000 VL 341 BP 387 EP 390 DI 10.1016/S0921-4534(00)00518-9 PN 1 PG 4 WC Physics, Applied SC Physics GA 382YT UT WOS:000165855500135 ER PT J AU Tetenbaum, M Maroni, VA Murphy, NM Dorris, SE AF Tetenbaum, M Maroni, VA Murphy, NM Dorris, SE TI Phase stability domains of (Bi,Pb)-2223: Data sources, correlation, and assessment SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID LEAD-DOPED BI-2223; THERMODYNAMIC BEHAVIOR; OXYGEN; SILVER; (BI,PB)(2)SR2CA2CU3OX; TEMPERATURE; SYSTEM; BI AB An assessment of the phase stability of lead-doped Bi-2223, (Bi,fb)-2223, as a function of temperature and partial pressure of oxygen, p(O-2), derived from equilibration and electromotive force studies carried out by numerous groups of investigators is presented. The data obtained from this assessment, coupled with additional more recent data from our laboratory, can be used to estimate the stability of this promising high-Tc bismuth cuprate system in the temperature range From 650 to 870 degreesC and for oxygen partial pressures ranging from 10(-5) to one atm. For oxygen contents above pO(2)=0.02 atm, the stability boundaries are reasonably well known. For smaller pO(2), discrepancies are found. C1 Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. RP Tetenbaum, M (reprint author), Argonne Natl Lab, Div Chem Technol, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 9 TC 5 Z9 5 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 NOV PY 2000 VL 341 BP 497 EP 498 DI 10.1016/S0921-4534(00)00560-8 PN 1 PG 2 WC Physics, Applied SC Physics GA 382YT UT WOS:000165855500178 ER PT J AU Serquis, A Fabrega, L Morales, L Basset, A Caneiro, A Fontcuberta, J Short, S Hodges, JP Jorgensen, J AF Serquis, A Fabrega, L Morales, L Basset, A Caneiro, A Fontcuberta, J Short, S Hodges, JP Jorgensen, J TI Thermodynamic and superconducting properties of Hg1-xRexBa2CuOy SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS AB Single phase materials of Hg1-xRexBa2CuOy samples were obtained for 0.00 < x < 0.15. They were studied by thermogravimetry under controlled p(O-2) to analyze the influence of Re on their chemical stability, oxygen nonstoichiometry and thermodynamic properties. Under and over-doped samples were obtained by changing the oxygen content. The oxygen content was determined by neutron diffraction and thermogravimetric measurements. The role of Re on the superconducting behavior and the improvement of the chemical stability of the Hg-1201 compounds is discussed. C1 CNEA, Ctr Atom Bariloche, RA-8400 Buenos Aires, DF, Argentina. CSIC, Inst Ciencia Mat Barcelona, E-08193 Barcelona, Spain. Univ Nacl Comahue, Neuquen, Argentina. Argonne Natl Lab, Argonne, IL 60439 USA. RP Serquis, A (reprint author), CNEA, Ctr Atom Bariloche, RA-8400 Buenos Aires, DF, Argentina. RI Fontcuberta, Josep /A-7114-2013; Hodges, Jason/K-1421-2013; Fabrega, Lourdes/L-5090-2014; OI Fabrega, Lourdes/0000-0002-2611-8037; Hodges, Jason/0000-0003-3016-4578; Fontcuberta, Josep/0000-0002-7955-2320; Serquis, Adriana/0000-0003-1499-4782 NR 4 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 511 EP 512 DI 10.1016/S0921-4534(00)00567-0 PN 1 PG 2 WC Physics, Applied SC Physics GA 382YT UT WOS:000165855500185 ER PT J AU Potrepka, DM Budnick, JI Moodenbaugh, AR Fischer, DA Hines, WA AF Potrepka, DM Budnick, JI Moodenbaugh, AR Fischer, DA Hines, WA TI Combined Cu-63,Cu-65 NQR and NMR study of Y1-xCaxBa2Cu3Oy SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID TEMPERATURE AB Zero-field Cu-63,Cu-65 nuclear quadrupole resonance (NQR) and nuclear magnetic resonance (NMR) spectra were obtained at 1.3 K for powdered samples of Y1-xCaxBa2Cu3OY with 0 less than or equal to x less than or equal to 0.20. The results for the deoxygenated samples (y = 6.05) demonstrate the existence of an internal magnetic field at the Cu(2) planar sites for Ca content x less than or equal to 0.20 and provide insight into the coexistence of superconductivity and antiferromagnetic correlations as a function of hole doping in the CuO2 planes due to Ca substitution. C1 Univ Connecticut, Dept Phys, Storrs, CT 06269 USA. Univ Connecticut, Inst Mat Sci, Storrs, CT 06269 USA. ARL, Sensors & Elect Devices Directorate, Adelphi, MD 20783 USA. Brookhaven Natl Lab, Div Mat Sci, Upton, NY 11973 USA. NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Potrepka, DM (reprint author), Univ Connecticut, Dept Phys, Storrs, CT 06269 USA. OI Potrepka, Daniel/0000-0002-0528-1038; Moodenbaugh, Arnold/0000-0002-3415-6762 NR 5 TC 0 Z9 0 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 611 EP 612 DI 10.1016/S0921-4534(00)00613-4 PN 1 PG 2 WC Physics, Applied SC Physics GA 382YT UT WOS:000165855500231 ER PT J AU Xu, YW Kramer, MJ Dennis, KW Wu, H O'Connor, A McCallum, RW Malik, SK Yelon, WB AF Xu, YW Kramer, MJ Dennis, KW Wu, H O'Connor, A McCallum, RW Malik, SK Yelon, WB TI Substitution for Ba by light rare-earth in Eu123 solid solutions SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS AB A detailed study on a series samples of Eu(Ba1-xRx)(2)Cu3O7+delta (R = La, Pr and Eu) was performed using X-ray diffraction, neutron diffraction, magnetic measurements and thermopower measurements. The effect of Pr in this compound was compared to two other rare earths, and we believe that the fast suppression of T-c by Pr substitution in this structure is electronic in nature. C1 Minnesota State Univ, Mankato, MN 56001 USA. Iowa State Univ, US Dept Energy, Ames Lab, Ames, IA 50011 USA. Tata Inst Fundamental Res, Bombay 400005, Maharashtra, India. Univ Missouri, Res Reactor, Columbia, MO 65211 USA. RP Xu, YW (reprint author), Minnesota State Univ, Mankato, MN 56001 USA. NR 3 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 613 EP 614 DI 10.1016/S0921-4534(00)00614-6 PN 1 PG 2 WC Physics, Applied SC Physics GA 382YT UT WOS:000165855500232 ER PT J AU Ono, S Ando, Y Murayama, T Balakirev, FF Betts, JB Boebinger, GS AF Ono, S Ando, Y Murayama, T Balakirev, FF Betts, JB Boebinger, GS TI Low-temperature normal state of Bi-2201 in a wide doping range: Where does the metal to insulator crossover take place? SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID LA2-XSRXCUO4 AB By suppressing the superconductivity with 60-T pulsed magnetic fields, the in-plane normal-state resistivity rho (ab) is measured down to 0.5 K in Bi2Sr2-xLaxCuO6+delta single crystals with varying carrier concentration. It is observed that a metallic behavior (d rho (ab)/dT greater than or equal to 0) gradually changes to an insulating one (d rho (ab)/dT < 0) with decreasing carrier concentration and that this crossover takes place in the underdoped region, not at the optimum doping. This result is notably distinct from that reported for La2-xSrxCuO4 or for Pr2-xCexCuO4+, indicating that the metal-to-insulator crossover in cuprates is not universally associated with the optimum doping. C1 CRIEPI, Tokyo 2018511, Japan. Sci Univ Tokyo, Dept Phys, Shinjuku Ku, Tokyo 1628601, Japan. Univ Calif Los Alamos Natl Lab, NHMFL, Los Alamos, NM 87545 USA. RP Ono, S (reprint author), CRIEPI, Tokyo 2018511, Japan. RI Ando, Yoichi/B-8163-2013 OI Ando, Yoichi/0000-0002-3553-3355 NR 5 TC 0 Z9 0 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 641 EP 642 DI 10.1016/S0921-4534(00)00628-6 PN 1 PG 2 WC Physics, Applied SC Physics GA 382YT UT WOS:000165855500246 ER PT J AU Murphy, NM Dorris, SE Miller, DJ Luo, ZP Claus, H Maroni, VA AF Murphy, NM Dorris, SE Miller, DJ Luo, ZP Claus, H Maroni, VA TI Phase formation and superconductivity in PIT-type (Bi,Pb)-1212 SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS AB It was shown via powder-in-tube (PIT) processing that the (Bi,Pb)-1212 phase with a textured microstructure readily forms inside a silver sheath at 920 degreesC in air. Composition, oxygen pressure, time, and temperature were all varied to study their effects on (Bi,Pb)-1212 phase purity and superconductivity. No evidence was found to support several prior claims that (Bi,Pb)-1212 is superconducting. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Murphy, NM (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Luo, Zhiping/C-4435-2014 OI Luo, Zhiping/0000-0002-8264-6424 NR 7 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 657 EP 658 PN 1 PG 2 WC Physics, Applied SC Physics GA 382YT UT WOS:000165855500254 ER PT J AU Hennings, BD Rathnayaka, KDD Naugle, DG Canfield, PC AF Hennings, BD Rathnayaka, KDD Naugle, DG Canfield, PC TI Thermal conductivity of rare-earth nickel borocarbides SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID SINGLE-CRYSTALS; SUPERCONDUCTORS; LUNI2B2C; HEAT AB YNi2B2C and LuNi2B2C are relatively high T-c superconductors (T-c=15.6K and 16.6K, respectively) for quaternary intermetallic compounds. Recent neutron scattering experiments show anomalous phonon behavior below T-c for both YNi2B2C and LuNi2B2C. Thermal conductivity measurements have been performed and indicate a strong enhancement below T-c in the thermal conductivity of LuNi2B2C, and a weaker enhancement below T-c for YNi2B2C which is similar to measurements previously reported by others for YNi2B2C. C1 Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Hennings, BD (reprint author), Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. RI Canfield, Paul/H-2698-2014 NR 9 TC 5 Z9 5 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 753 EP 754 DI 10.1016/S0921-4534(00)00676-6 PN 2 PG 2 WC Physics, Applied SC Physics GA 382YV UT WOS:000165855700023 ER PT J AU Hasan, MZ Isaacs, ED Shen, ZX Miller, LL AF Hasan, MZ Isaacs, ED Shen, ZX Miller, LL TI Particle-hole excitations in insulating antiferromagnet Ca2CuO2Cl2 SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID X-RAY-SCATTERING; SR2CUO2CL2 AB We briefly report results of an x-ray scattering study of particle-hole excitations in a cuprate insulator. The excitation spectrum shows a broad feature around 5.7 eV and a dispersive feature around 2.5 eV energy-loss. The low energy feature disperses upward about 0.8 eV along [110] having momentum-transfers (Q) from (2.1 pi ,2.1 pi) to (1.2 pi, 1.2 pi); whereas, it does not disperse much along [100] in going from (1.42 pi ,0) to (2.85 pi ,0) within the level of energy resolution of 0.56 eV. This dispersive behavior of particle-hole excitations is mostly determined by the underlying strong magnetic correlations. C1 Stanford Univ, SLAC, Phys & Stanford Synchr Rad Lab, Dept Appl Phys, Stanford, CA 94305 USA. Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Hasan, MZ (reprint author), Stanford Univ, SLAC, Phys & Stanford Synchr Rad Lab, Dept Appl Phys, Stanford, CA 94305 USA. RI HASAN, M. Zahid/D-8237-2012 NR 10 TC 4 Z9 4 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 NOV PY 2000 VL 341 BP 781 EP 782 DI 10.1016/S0921-4534(00)00690-0 PN 2 PG 2 WC Physics, Applied SC Physics GA 382YV UT WOS:000165855700037 ER PT J AU Almasan, CC Zhang, CL Levin, GA Gardner, JS AF Almasan, CC Zhang, CL Levin, GA Gardner, JS TI Temperature and field dependence of resistivities and anisotropy of layered manganites La2-2xSr1+2xMn2O7 SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS AB In-plane rho (ab) and out-of-plane rho (c) resistivities of L alpha 1.2Sr1.8Mn2O7 and LaSr2Mn2O7 have been measured by a multiterminal technique. We focus on the effects that magnetic and charge ordering transitions have on the anisotropy sigma (ab)/sigma (c) which reflects the ratio of the phase coherence lengths in the respective directions. Both resistivities of La1.2Sr1.8Mn2O7 decrease dramatically below the Curie temperature T-C approximate to 135 K. Anisotropy changes with temperature nonmonotonically and displays a peak close to T-C. In LaSr2Mn2O7, rho (c) and rho (ab) display a broad peak close to the paramagnetic-antiferromagnetic transition temperature T-N approximate to 165 K. The anisotropy exhibits an even more complex behavior than in (La12Sr1.8Mn2O7)-Sr-., displaying a maximum at the charge ordering temperature and a minimum at T-N. C1 Kent State Univ, Dept Phys, Kent, OH 44242 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Almasan, CC (reprint author), Kent State Univ, Dept Phys, Kent, OH 44242 USA. RI Gardner, Jason/A-1532-2013 NR 5 TC 1 Z9 1 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 791 EP 792 DI 10.1016/S0921-4534(00)00695-X PN 2 PG 2 WC Physics, Applied SC Physics GA 382YV UT WOS:000165855700042 ER PT J AU Balatsky, AV Kumar, P Schrieffer, JR AF Balatsky, AV Kumar, P Schrieffer, JR TI Clapping modes in unconventional superconductors SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID D-WAVE SUPERCONDUCTORS; T-C SUPERCONDUCTORS; SYMMETRY ORDER PARAMETERS; TIME-REVERSAL SYMMETRY; SURFACE-STATES; D(X(2)-Y(2))-WAVE; COEXISTENCE; BREAKING; VORTEX AB We consider a superconducting state with a mixed symmetry order parameter components, e.g. d+is or d+id' with d' = d(xy). We argue for the existence of the new orbital magnetization mode which corresponds to the oscillations of relative phase phi between two components around an equilibrium value of phi = 5. It is similar to the so called "clapping" mode in superfluid He-3 - A. We estimate the frequency of this made omega (0)(B,T) depending on the field and temperature for the specific case of magnetic field induced d' state. We find that this mode is tunable with an applied magnetic field with omega (0)(B,T) proportional to B Delta (0), where Delta (0) is the magnitude of the d-wave order parameter. We argue also that similar filed induced clapping mode should be present in an organic p-wave superconductors. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Florida, Dept Phys, Gainesville, FL 32611 USA. Florida State Univ, NHMFL, Tallahassee, FL 32310 USA. RP Balatsky, AV (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 27 TC 0 Z9 0 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 NOV PY 2000 VL 341 BP 807 EP 810 DI 10.1016/S0921-4534(00)00700-0 PN 2 PG 4 WC Physics, Applied SC Physics GA 382YV UT WOS:000165855700047 ER PT J AU Miyakawa, N Zasadzinski, JF Ozyuzer, L Guptasarma, P Kendziora, C Hinks, DG Kaneko, T Gray, KE AF Miyakawa, N Zasadzinski, JF Ozyuzer, L Guptasarma, P Kendziora, C Hinks, DG Kaneko, T Gray, KE TI Superconducting gap and pseudogap from tunneling conductance on Bi2Sr2CaCu2O8+delta with various oxygen concentration SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID T-C SUPERCONDUCTORS; OVERDOPED BI2SR2CACU2O8+DELTA; SPECTROSCOPY; PARTICLE AB The evolution of tunneling spectra on Bi2Sr2CaCu2O8+delta measured by SIN point contacts, SIS break junctions and STM/STS has been studied as a function of doping and temperature. The detailed examinations of the spectra show that the energy gap measured at low temperature appear to be due to superconducting pairing. The doping dependence of the superconducting gap at low temperature suggests a strong connection to the pseudogap temperature, T*, and this indicates that the pseudogap region is at least partly a consequence of some form of precursor superconductivity. In addition, dip/hump structures observed at high bias scale approximately with not only Delta but also superexchange interaction J over the entire doping range examined, indicating these features are linked to the underlying interaction responsible for superconductivity. We suggest that the hump structure may originate from short-range magnetic correlations. C1 Sci Univ Tokyo, Dept Appl Phys, Shinjuku Ku, Tokyo 1628601, Japan. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. IIT, Chicago, IL 60616 USA. Izmir Inst Technol, Dept Phys, TR-35230 Izmir, Turkey. USN, Res Lab, Washington, DC 20375 USA. RP Miyakawa, N (reprint author), Sci Univ Tokyo, Dept Appl Phys, Shinjuku Ku, 1-3 Kagurazaka, Tokyo 1628601, Japan. RI Ozyuzer, Lutfi/H-3142-2011 NR 12 TC 16 Z9 16 U1 1 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 NOV PY 2000 VL 341 BP 835 EP 838 DI 10.1016/S0921-4534(00)00707-3 PN 2 PG 4 WC Physics, Applied SC Physics GA 382YV UT WOS:000165855700054 ER PT J AU Klemm, RA AF Klemm, RA TI Striking similarities between the pseudogap phenomena in cuprates and in layered organic and dichalcogenide superconductors SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID CHARGE-DENSITY-WAVE; T-C; NORMAL-STATE; SINGLE-CRYSTAL; SPIN GAP; C-13 NMR; BI2SR2CACU2O8+DELTA; 2H-TASE2; YBA2CU3O7-DELTA; 2H-NBSE2 AB Underdoped high temperature superconductors (HTS) exhibit a 'normal' state for energies E > E-g and/or temperatures T > T-0, and a pseudogap in their electronic spectrum for E < E-g and/or T-0 > T > T-c. Strikingly similar behavior occurs in the transition metal dichalcogenides (TMD) 2H-MX2, where M = Ta, Nb, and X = S, Se, both in the 'normal' (T > T-0) and in the incommensurate charge-density wave (T-10DW > T > T-c) states. Such strikingly similar behavior has also been seen in the organic layered superconductors (OLS) kappa-(ET)(2)X, where ET is bis(ethylenedithio)tetrathiafulvalene, and X = Cu[N(CN)(2)]Cl, Cu[N(CN)(2)]Br, and Cu(SCN)(2), both in the 'normal' region T > T-SDW > T-c and in the spin-density wave region T-SDW > T > T-c. In all three materials classes, the anomalous transport and thermodynamic properties associated with the pseudogap or density-wave regime are completely independent of the applied magnetic field strength, whereas the same properties below T-c are all strongly field-dependent. Hence, we propose that the pseudogap in the HTS arises from charge- and/or spin-density waves, and not from either superconducting fluctuations or "preformed" charged quasiparticle pairs. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Klemm, RA (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 40 TC 34 Z9 34 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 839 EP 842 DI 10.1016/S0921-4534(00)00708-5 PN 2 PG 4 WC Physics, Applied SC Physics GA 382YV UT WOS:000165855700055 ER PT J AU Zasadzinski, JF Ozyuzer, L Miyakawa, N Hinks, DG Gray, KE AF Zasadzinski, JF Ozyuzer, L Miyakawa, N Hinks, DG Gray, KE TI High energy secondary peak structure in tunneling spectra (hump) as possible magnetic pseudogap SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID SUPERCONDUCTORS; SPECTROSCOPY AB It is demonstrated that tunneling spectra in various high T-c cuprates display generic features. The principal conductance peaks in superconductor-insulator-normal metal (SIN) junctions indicate the superconducting gap in the density of states (DOS). Higher energy features include a dip and hump structure with a strength that is asymmetric in bias voltage. The dip and hump features follow the doping trends of the superconducting gap, Delta, with a rough scaling as similar to2 Delta and similar to3 Delta respectively. Tunneling spectra in underdoped Bi2Sr2CaCu2O8+delta display a more pronounced hump feature suggestive of a second gap in the DOS. It is observed that the hump feature in the tunneling density of states is consistent with other experimental observations of the so-called high energy pseudogap which may have magnetic origins. C1 IIT, Div Phys, Chicago, IL 60616 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Izmir Inst Technol, Dept Phys, TR-35230 Izmir, Turkey. Sci Univ Tokyo, Dept Appl Phys, Tokyo 1628601, Japan. RP Zasadzinski, JF (reprint author), IIT, Div Phys, Chicago, IL 60616 USA. RI Ozyuzer, Lutfi/H-3142-2011 NR 11 TC 14 Z9 14 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 NOV PY 2000 VL 341 BP 867 EP 870 DI 10.1016/S0921-4534(00)00715-2 PN 2 PG 4 WC Physics, Applied SC Physics GA 382YV UT WOS:000165855700062 ER PT J AU Ozyuzer, L Zasadzinski, JF Miyakawa, N Kendziora, C Sha, J Hinks, DG Gray, KE AF Ozyuzer, L Zasadzinski, JF Miyakawa, N Kendziora, C Sha, J Hinks, DG Gray, KE TI Tunneling spectroscopy of heavily underdoped crystals of Bi2Sr2CaCu2O8+delta SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS AB Crystals of Bi2Sr2CaCu2O8+delta With optimal T-c=95 K have been underdoped using two different methods and the superconducting gaps have been obtained by tunneling. In some cases, three different tunneling geometries have been utilized: point contact, STM and break junctions. The first doping method involves control of the oxygen content by annealing in various partial pressures of oxygen. These crystals exhibit a narrow spread of gap values over a wide doping range from overdoped (T-c=56 K) to underdoped with T-c=70 K. However, for underdoped crystals with T-c midpoints in the range 25 K - 63 K, there is a dramatic increase in the spread of gap values which may signal the development of static phase separation of either chemical or electronic origin. To avoid possible chemical phase separation, we have explored another doping procedure which incorporates Dy substitution on the Ca site. These crystals exhibit a relatively narrow superconducting transition width and some preliminary tunneling spectra will be presented. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Izmir Inst Technol, Dept Phys, TR-35230 Izmir, Turkey. IIT, Chicago, IL 60616 USA. Sci Univ Tokyo, Dept Appl Phys, Tokyo 1628601, Japan. USN, Res Lab, Washington, DC 20375 USA. RP Ozyuzer, L (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Ozyuzer, Lutfi/H-3142-2011 NR 3 TC 3 Z9 3 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 NOV PY 2000 VL 341 BP 927 EP 928 DI 10.1016/S0921-4534(00)00739-5 PN 2 PG 2 WC Physics, Applied SC Physics GA 382YV UT WOS:000165855700086 ER PT J AU Marcenat, C Bouquet, F Calemczuk, R Welp, U Kwok, WK Crabtree, GW Phillips, NE Fisher, RA Schilling, A AF Marcenat, C Bouquet, F Calemczuk, R Welp, U Kwok, WK Crabtree, GW Phillips, NE Fisher, RA Schilling, A TI The vortex states of YBa2Cu3O7-delta: phase diagram; calorimetric and magnetic properties SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID LATTICE-MELTING TRANSITION; LINE; CRYSTALS; DISORDER; POINT; HEAT AB We report measurements of both the specific heat (C) and the magnetization (M) of a naturally untwinned YBa2Cu3O7-delta(YBCO) single crystal in magnetic field (H) up to 26 Tesla. The specific heat data determine the thermodynamic nature of the melting and show its evolution with increasing H within a low-H region (0.1 less than or equal to H less than or equal to 10.5 Tesla) in which it is first order, with a discontinuity in C and a hysteretic latent heat, through a multicritical point, and into a high-H region (10.5 I H I 26 Tesla) in which it is second order, with only a discontinuity in C. The qualitative change in melting in that latter region seems to reflect not a change in the nature of the solid but rather that of the (reversible) liquid. The M data show the relation of irreversibility to melting and allow to distinguish between the thermodynamic features at melting to disorder-dependent properties of the solid. C1 CEA, Dept Rech Fondamentale Mat Condensee, SPSMS, F-38054 Grenoble, France. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Zurich, Inst Phys, CH-8057 Zurich, Switzerland. RP Marcenat, C (reprint author), CEA, Dept Rech Fondamentale Mat Condensee, SPSMS, F-38054 Grenoble, France. NR 14 TC 5 Z9 5 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 949 EP 952 DI 10.1016/S0921-4534(00)00749-8 PN 2 PG 4 WC Physics, Applied SC Physics GA 382YV UT WOS:000165855700096 ER PT J AU Kwok, WK Olsson, RJ Karapetrov, G Paulius, LM Moulton, WG Hofman, DJ Crabtree, GW AF Kwok, WK Olsson, RJ Karapetrov, G Paulius, LM Moulton, WG Hofman, DJ Crabtree, GW TI Effect of defects on the critical points in YBa2Cu3O7-delta SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID LATTICE MELTING TRANSITION; VORTEX-LATTICE; BOSON LOCALIZATION; OXYGEN DEFICIENCY; PHASE-DIAGRAM; DISORDER; LINE; IMPURITIES; CRYSTALS; SYSTEM AB The upper and lower critical points are investigated in untwinned YBa2Cu3O7-delta single crystals with dilute columnar defects. Dilute columnar defects raise the upper critical point, indicating that the transition near the upper critical point is a vortex entanglement transition. The lower critical point is very sensitive to columnar defect disorder and its position can be described by a Lindemann-like criterion similar to that for melting. Dilute columnar defects induce non-linear behavior in the I-V curves of the vortex liquid state above the lower critical point, which we interpret as a vestige of the critical region associated with the Bose glass transition below the lower critical point. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Western Michigan Univ, Dept Phys, Kalamazoo, MI 49008 USA. Florida State Univ, Dept Phys, Natl High Magnet Field Lab, Tallahassee, FL 32306 USA. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. RP Kwok, WK (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Karapetrov, Goran/C-2840-2008 OI Karapetrov, Goran/0000-0003-1113-0137 NR 24 TC 1 Z9 1 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 NOV PY 2000 VL 341 BP 953 EP 956 DI 10.1016/S0921-4534(00)00750-4 PN 2 PG 4 WC Physics, Applied SC Physics GA 382YV UT WOS:000165855700097 ER PT J AU Moler, KA Kirtley, JR Liang, RX Bonn, DA Hardy, WN Williams, JM Schlueter, JA Hinks, D Villard, G Maignan, A Nohara, M Takagi, H AF Moler, KA Kirtley, JR Liang, RX Bonn, DA Hardy, WN Williams, JM Schlueter, JA Hinks, D Villard, G Maignan, A Nohara, M Takagi, H TI Images of interlayer Josephson vortices in single-layer cuprates SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID SCANNING SQUID MICROSCOPE; PENETRATION DEPTH; SUPERCONDUCTIVITY; MECHANISM; DESIGN AB The interlayer penetration depth in layered superconductors may be determined from scanning Superconducting QUantum Interference Device (SQUID) microscope images of interlayer Josephson vortices. We compare our findings at 4 K for single crystals of the organic superconductor kappa-(BEDT-TTF)(2)Cu(NCS)(2) and three near-optimally doped cuprate superconductors: La2-xSrxCuO4, (Hg,Cu)Ba2CuO4+delta, and Tl2Ba2CuO6+delta. C1 Stanford Univ, Dept Appl Phys, Stanford, CA 94305 USA. IBM Corp, Thomas J Watson Res Ctr, Yorktown Heights, NY 10598 USA. Univ British Columbia, Dept Phys & Astron, Vancouver, BC V6T 1Z1, Canada. Argonne Natl Lab, Div Chem & Mat Sci, Argonne, IL 60439 USA. ISMRA, CRISMAT, F-14050 Caen, France. Univ Tokyo, Inst Solid State Phys, Minato Ku, Tokyo 106, Japan. RP Moler, KA (reprint author), Stanford Univ, Dept Appl Phys, Stanford, CA 94305 USA. RI Takagi, Hidenori/B-2935-2010; Moler, Kathryn/F-2541-2011; NOHARA, Minoru/B-1476-2011 NR 20 TC 2 Z9 2 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 977 EP 980 DI 10.1016/S0921-4534(00)00756-5 PN 2 PG 4 WC Physics, Applied SC Physics GA 382YV UT WOS:000165855700103 ER PT J AU Kunchur, MN Ivlev, BI Christen, DK Phillips, JM AF Kunchur, MN Ivlev, BI Christen, DK Phillips, JM TI Vortex instability and the normal state at low temperatures SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID UPPER CRITICAL-FIELD; SUPERCONDUCTING LA2-XSRXCUO4; THIN-FILMS; FLUX-FLOW; YBA2CU3O7-DELTA; LAALO3(100); TRANSITION; BEHAVIOR; CORE AB The motion of flux vortices in Y1Ba2Cu3O7-delta has been studied in the low temperature limit (T similar to 2% of T-c) at extreme current and dissipation densities (P/V similar to 10(9) W/cm(3)). Beyond the regime where flux motion is driven into free how, occurs an instability that seems to arise from a suppression of the order parameter. The critical resistivity at the point of instability is roughly twice the free-flux-flow value rho*/rho (n) similar to 2 rho (f) similar to 2B/H-c2, allowing an estimation of the illusive normal-state resistivity, p(n), in the zero-temperature limit. The estimated p(n) saturates to a finite residual value, like a conventional elemental superconductor, and the vortex dissipation continues to be finite as T --> 0. C1 Univ S Carolina, Dept Phys & Astron, Columbia, SC 29208 USA. Univ Autronoma San Luis Potosi, San Luis Potosi, Mexico. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Kunchur, MN (reprint author), Univ S Carolina, Dept Phys & Astron, Columbia, SC 29208 USA. NR 22 TC 0 Z9 0 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 NOV PY 2000 VL 341 BP 1003 EP 1006 DI 10.1016/S0921-4534(00)00763-2 PN 2 PG 4 WC Physics, Applied SC Physics GA 382YV UT WOS:000165855700110 ER PT J AU Kolton, AB Dominguez, D Gronbech-Jensen, N AF Kolton, AB Dominguez, D Gronbech-Jensen, N TI Dynamical ordering in the c-axis in 3D driven vortex lattices SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID FLUX-LINE-LATTICE; PERIODIC MEDIA; PHASE-DIAGRAM; LOGARITHMIC INTERACTIONS; LAYERED SUPERCONDUCTORS; DISORDER; TRANSITION; SUMMATION; VORTICES; FILMS AB We present molecular dynamics simulations of driven vortices in layered superconductors in the presence of an external homogeneous force and point disorder. We use a model introduced by J.R.Clem for describing 3D vortex lines as stacks of 2D pancake Vortices where only magnetic interactions are considered and the Josephson interlayer coupling is neglected. We numerically evaluate the long-range magnetic interaction between pancake vortices exactly. We analyze the vortex correlation along the field direction on (c-axis). We find that above the critical current, in the "plastic flow" regime, pancakes are completely uncorrelated in the c-direction. When increasing the current, there is an onset of correlation along the c-axis at the transition from plastic flow to a moving smectic phase. This transition coincides with the peak in the differential resistance. C1 Ctr Atom Bariloche, RA-8400 Bariloche, Rio Negro, Argentina. Univ Calif Davis, Dept Appl Sci, Davis, CA 95616 USA. Lawrence Berkeley Natl Lab, NERSC, Berkeley, CA 94720 USA. RP Kolton, AB (reprint author), Ctr Atom Bariloche, RA-8400 Bariloche, Rio Negro, Argentina. RI Dominguez, Daniel/E-9304-2016; OI Dominguez, Daniel/0000-0002-6204-0150; Kolton, Alejandro B./0000-0002-9050-5859 NR 29 TC 5 Z9 5 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 NOV PY 2000 VL 341 BP 1007 EP 1010 DI 10.1016/S0921-4534(00)00764-4 PN 2 PG 4 WC Physics, Applied SC Physics GA 382YV UT WOS:000165855700111 ER PT J AU Olson, CJ Gronbech-Jensen, N AF Olson, CJ Gronbech-Jensen, N TI Depinning and dynamic phases in driven three-dimensional vortex lattices in anisotropic superconductors SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS AB We use three-dimensional molecular dynamics simulations of magnetically interacting pancake vortices to study the dynamic phases of vortex lattices in highly anisotropic materials such as BSCCO. Our model treats the magnetic interactions of the pancakes exactly, with long-range logarithmic interactions both within and between planes. The pancake vortices decouple at low drives and show two-dimensional plastic flow. The vortex lattice both recouples and reorders as the driving current is increased, eventually forming a recoupled crystalline-like state at high drives. We construct a phase diagram as a function of interlayer coupling and show the relationship between the recoupling transition and the single-layer reordering transitions. C1 Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Univ Calif Davis, Dept Appl Sci, Davis, CA 95616 USA. Lawrence Berkeley Lab, NERSC, Berkeley, CA 94720 USA. RP Olson, CJ (reprint author), Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. NR 7 TC 2 Z9 2 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 NOV PY 2000 VL 341 BP 1083 EP 1084 DI 10.1016/S0921-4534(00)00794-2 PN 2 PG 2 WC Physics, Applied SC Physics GA 382YV UT WOS:000165855700141 ER PT J AU Santiago, RD Krupski, AM Boekema, C Cooke, DW AF Santiago, RD Krupski, AM Boekema, C Cooke, DW TI D-wave symmetry in Bi2212 and TI2223 vortex states: an ME-mu SR study SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID SUPERCONDUCTORS; DEPENDENCE; LATTICE AB The vortex states of Bi2212 and Tl2223 have been studied by muon-spin resonance (mu SR). Similar to d-wave order predictions, and as recently found for M1237, twin-peak signatures in the main Vortex signals have been observed at 5 kOe, below T/T-C = 0.8. The twin-peak splitting is proportional to {1 - (T/T-C)(n)},with n about 3. C1 San Jose State Univ, Dept Phys, San Jose, CA 95192 USA. Natl High Magnet Field Lab, Tallahassee, FL 32310 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Santiago, RD (reprint author), San Jose State Univ, Dept Phys, San Jose, CA 95192 USA. NR 13 TC 3 Z9 3 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 NOV PY 2000 VL 341 BP 1097 EP 1098 DI 10.1016/S0921-4534(00)00801-7 PN 2 PG 2 WC Physics, Applied SC Physics GA 382YV UT WOS:000165855700148 ER PT J AU Prozorov, R Giannetta, RW Tamegai, T Guptasarma, P Hinks, DG AF Prozorov, R Giannetta, RW Tamegai, T Guptasarma, P Hinks, DG TI Low temperature vortex phase diagram of Bi2.15Sr1.85CaCu2O8+delta: a magnetic penetrtudy SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID CROSSOVER; CRYSTALS AB We report measurements of the magnetic penetration depth lambda (m)(T) in the presence of a DC magnetic field in optimally doped BSCCO-2212 single crystals. Warming, after magnetic field is applied to a zero-field cooled sample, results in a non-monotonic lambda (m)(T), which does not coincide with a curve obtained upon field cooling, thus exhibiting a hysteretic behaviour. We discuss the possible relation of our results to the vortex decoupling, unbinding, and dimensional crossover. C1 Univ Illinois, Loomis Lab Phys, Urbana, IL 61801 USA. Univ Tokyo, Dept Appl Phys, Bunkyo Ku, Tokyo 113, Japan. Argonne Natl Lab, Div Chem & Mat Sci, Argonne, IL 60439 USA. RP Prozorov, R (reprint author), Univ Illinois, Loomis Lab Phys, 1110 W Green St, Urbana, IL 61801 USA. RI Tamegai, Tsuyoshi /C-6656-2011; Prozorov, Ruslan/A-2487-2008 OI Prozorov, Ruslan/0000-0002-8088-6096 NR 7 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 1123 EP 1124 DI 10.1016/S0921-4534(00)00814-5 PN 2 PG 2 WC Physics, Applied SC Physics GA 382YV UT WOS:000165855700161 ER PT J AU Salem-Sugui, S Alvarenga, AD Ortiz, WA Ghivelder, L Paulikas, P Veal, B AF Salem-Sugui, S Alvarenga, AD Ortiz, WA Ghivelder, L Paulikas, P Veal, B TI Absence of pinning mechanism change in the second magnetization peak of YBa2Cu3O6.5 at low temperature SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID HYSTERESIS-LOOP; SUPERCONDUCTORS; DEPENDENCE; CURVES AB We have measured hysteresis curves M(H) and magnetic relaxation M(t) for a YBa2Cu3O6.5 single crystal (Tc = 62.5 K) with the magnetic field H // c axis. Magnetic relaxation was measured for values of field below and above the second magnetization peak Hp in hysteresis curves, at 1.8, 4.4 and 20 K. The activation pinning energy U is obtained from relaxation data, generating U(M) vs M(t) curves. All U(M) curves follow a power law behavior U similar to M-alpha. At 20 K and 4.4 K the curves U(M) obtained for fields below the second peak Hp, presents a distinct behavior from the curves obtained for fields above Hp. At 1.8 K all U(H,M) curves present the same power law behavior with alpha similar to 1.5. This fact highly suggests the existence of the second magnetization peak with only one pinning mechanism. C1 UFRJ, Inst Fis, BR-21945970 Rio De Janeiro, Brazil. Ctr Brasileiro Pesquisas Fis, BR-22290180 Rio De Janeiro, Brazil. UFSCar, Dept Fis, BR-13565905 Sao Carlos, SP, Brazil. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Salem-Sugui, S (reprint author), UFRJ, Inst Fis, CP 68528, BR-21945970 Rio De Janeiro, Brazil. RI Alvarenga, Ana Paula/M-9790-2014; Ortiz, Wilson/K-7379-2012; GHIVELDER, LUIS/L-1820-2015 OI GHIVELDER, LUIS/0000-0002-5667-6531 NR 9 TC 0 Z9 0 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 NOV PY 2000 VL 341 BP 1131 EP 1132 DI 10.1016/S0921-4534(00)00818-2 PN 2 PG 2 WC Physics, Applied SC Physics GA 382YV UT WOS:000165855700165 ER PT J AU Kimura, K Koshida, R Okayasu, S Sataka, M Kazumata, Y Kwok, WK Crabtree, GW Kadowaki, K AF Kimura, K Koshida, R Okayasu, S Sataka, M Kazumata, Y Kwok, WK Crabtree, GW Kadowaki, K TI Weak pinning phenomena in liquid state in Bi2Sr2CaCu2O8+delta with columnar defects SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID II SUPERCONDUCTORS AB Anomalous weak pinning phenomena were found in the Vortex liquid state of Bi2Sr2CaCu2O8+delta single crystals with and without columnar defects up to B-Phi = 1 T between H-irr and H-F, at which the M-T curves show a sharp step-like feature. With increasing B-Phi H-F as well as H-irr is considerably pushed up. It is shown that the region defined by H-irr and H-F is very sensitive to the disorder and is greatly expanded by introducing columnar defects. These results strongly suggest appearance of the new phase in the vortex liquid region, which may be induced by the pinning effect. C1 Univ Tsukuba, Inst Mat Sci, Tsukuba, Ibaraki 3058573, Japan. Japan Atom Energy Res Inst, Naka, Ibaraki 3191195, Japan. Nihon Adv Technol Co, Naka, Ibaraki 3191106, Japan. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60435 USA. RP Kimura, K (reprint author), Univ Tsukuba, Inst Mat Sci, 1-1-1 Tennodai, Tsukuba, Ibaraki 3058573, Japan. NR 4 TC 1 Z9 1 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 NOV PY 2000 VL 341 BP 1133 EP 1134 DI 10.1016/S0921-4534(00)00822-4 PN 2 PG 2 WC Physics, Applied SC Physics GA 382YV UT WOS:000165855700166 ER PT J AU Narozhnyi, VN Fuchs, G Nenkov, K Eckert, D Teresiak, A Muller, KH Canfield, PC AF Narozhnyi, VN Fuchs, G Nenkov, K Eckert, D Teresiak, A Muller, KH Canfield, PC TI Dip anomaly in ac screening response and peak effect in LuNi2B2C and YNi2B2C single crystals SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID SUPERCONDUCTORS AB AC susceptibility and de magnetization have been studied for LuNi2B2C and YNi2B2C single crystals in magnetic fields H up to 50 kOe (H\\[001], [100], [110]). A pronounced dip anomaly in the ac screening response in the mixed state has been found for both compounds which was found to be connected with the peak effect of the superconducting critical current. C1 Inst Solid State & Mat Res, D-01171 Dresden, Germany. Russian Acad Sci, Inst High Pressure Phys, Troitsk 142092, Moscow Reg, Russia. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Narozhnyi, VN (reprint author), Inst Solid State & Mat Res, POB 270016, D-01171 Dresden, Germany. RI Canfield, Paul/H-2698-2014 NR 9 TC 2 Z9 2 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 NOV PY 2000 VL 341 BP 1141 EP 1142 DI 10.1016/S0921-4534(00)00826-1 PN 2 PG 2 WC Physics, Applied SC Physics GA 382YV UT WOS:000165855700170 ER PT J AU Gurevich, A Friesen, M Vinokur, V AF Gurevich, A Friesen, M Vinokur, V TI Nonlinear current flow and electric field domains in inhomogeneous superconductors SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID DEFECTS AB We show that both macroscopic planar defects and random inhomogeneities of superconducting properties cause strong local enhancement of electric field, which dramatically changes nonlinear current transport of superconductors. We find that even small planar defects can produce significant voltage peaks, while random inhomogeneities can cause a nonmonotonic dependence of J(c)(B), negative differential conductivity and electric field domains (superconducting Gunn effect). C1 Univ Wisconsin, Ctr Appl Superconduct, Madison, WI 53706 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Gurevich, A (reprint author), Univ Wisconsin, Ctr Appl Superconduct, 1500 Johnson Dr, Madison, WI 53706 USA. RI Gurevich, Alex/A-4327-2008 OI Gurevich, Alex/0000-0003-0759-8941 NR 5 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 1249 EP 1250 DI 10.1016/S0921-4534(00)01152-7 PN 2 PG 2 WC Physics, Applied SC Physics GA 382YV UT WOS:000165855700224 ER PT J AU Terentiev, AN Hull, JR De Long, LE AF Terentiev, AN Hull, JR De Long, LE TI Flux line depinning in a magnet-superconductor levitation system SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS AB The AC loss characteristics of a magnet-superconductor system were studied with the magnet fixed to the free end of an oscillating cantilever located near a stationary melt-textured YBCO pellet. Below a threshold AC field amplitude approximate to2 Oe, the dissipation of the oscillator is amplitude-independent, characteristic of a linear, non-hysteretic regime. Above threshold, dissipation increases with amplitude, reflecting the depinning and hysteretic motion of flux lines. The threshold AC field is an order of magnitude higher than that measured for the same YBCO material via AC susceptometry in a uniform DC magnetic field. A partial lock-in of flux lines between YBCO ab planes is proposed as the mechanism for the substantial increase of the depinning threshold. C1 Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. RP Terentiev, AN (reprint author), Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. NR 3 TC 2 Z9 2 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 1289 EP 1290 DI 10.1016/S0921-4534(00)00904-7 PN 2 PG 2 WC Physics, Applied SC Physics GA 382YV UT WOS:000165855700244 ER PT J AU Civale, L Silhanek, AV Thompson, JR Song, KJ Tomy, CV Paul, DM AF Civale, L Silhanek, AV Thompson, JR Song, KJ Tomy, CV Paul, DM TI Four-fold anisotropy of the basal plane magnetization of YNi2B2C: nonlocal effects SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID SUPERCONDUCTORS; LATTICE AB We present studies of the vortex state magnetization M of a single crystal of the nonmagnetic borocarbide superconductor YNi2B2C. With magnetic field H applied in the square basal plane of the tetragonal unit cell, M has a four-fold anisotropy. This pi /2 periodicity occurs deep in the superconductive mixed state, with an unusual field dependence, for a range of temperatures T < T-c. The observations are well explained by a generalized London model incorporating non-local electrodynamics, using parameters from complementary experiments. C1 Comis Nacl Energia Atom, Ctr Atom Bariloche, RA-8400 Bariloche, Rio Negro, Argentina. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands, England. RP Civale, L (reprint author), Comis Nacl Energia Atom, Ctr Atom Bariloche, RA-8400 Bariloche, Rio Negro, Argentina. 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 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 1299 EP 1300 DI 10.1016/S0921-4534(00)00909-6 PN 2 PG 2 WC Physics, Applied SC Physics GA 382YV UT WOS:000165855700249 ER PT J AU Shibauchi, T Nakano, T Sato, M Kisu, T Kameda, N Okuda, N Ooi, S Tamegai, T AF Shibauchi, T Nakano, T Sato, M Kisu, T Kameda, N Okuda, N Ooi, S Tamegai, T TI Interlayer phase coherence in the vortex matter phases of Bi2Sr2CaCu2O8+y SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID JOSEPHSON PLASMA RESONANCE; LAYERED SUPERCONDUCTORS; STATE; CRYSTALS AB The vortex matter phase diagram in Bi2Sr2CaCu2O8+delta is studied by the magnetization measurements and by Josephson plasma resonance. Above the first-order transition (FOT), sample-moving magnetization measurements show an anomaly suggesting the surface-barrier related transition (T-x line). We find a strong change in the interlayer phase coherence at the FOT and the second peak lines, indicating the decoupling nature of these lines. However, we find no anomaly in the interlayer phase coherence at the T-x line. These results rule out the existence of the vortex line liquid state. C1 IBM Corp, TJ Watson Res Ctr, Yorktown Heights, NY 10598 USA. Univ Calif Los Alamos Natl Lab, MST, STC, Los Alamos, NM 87545 USA. RP Shibauchi, T (reprint author), IBM Corp, TJ Watson Res Ctr, POB 218, Yorktown Heights, NY 10598 USA. RI Shibauchi, Takasada/B-9349-2008; Tamegai, Tsuyoshi /C-6656-2011 OI Shibauchi, Takasada/0000-0001-5831-4924; NR 12 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 1315 EP 1316 DI 10.1016/S0921-4534(00)00917-5 PN 2 PG 2 WC Physics, Applied SC Physics GA 382YV UT WOS:000165855700257 ER PT J AU Gray, KE Miller, DJ Field, MB Kim, DH Berghius, P AF Gray, KE Miller, DJ Field, MB Kim, DH Berghius, P TI Grain-boundary dissipation in high-T-c superconductors SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID TRANSPORT-PROPERTIES; CRITICAL CURRENTS; THIN-FILMS; YBA2CU3O7-DELTA; BICRYSTALS; MICROSTRUCTURE; MISORIENTATION; FLUX; BULK AB Thin-film and bulk [001] tilt bicrystal grain boundaries (GBs) in YBa2Cu3O7 exhibit a strong dependence of critical current density, J(c), on misorientation angle. What was initially difficult to understand was the 30x smaller J(c) in bulk GBs which are microscopically more perfect. We review an explanation of this zero-field data, which is based on the pinning of Josephson vortices by the meandering found in thin-film GBs. In addition, there is evidence that J(c) of GBs does not drop as quickly with applied magnetic field as expected by simple Josephson junction models. The long-wavelength pinning potential due to meandering is less effective at high fields, but Gurevich and Cooley (GC) proposed a new mechanism for an enhanced GB J(c) arising from pinned Abrikosov vortices in the banks of a GB which present a static, quasiperiodic pinning potential to pin GB vortices. We find a peak in J(c) and an unusual hysteresis which give considerable support to the GC concept. In low fields, the GBs exhibit a larger J(c) for field cooling, which is opposite to the usual hysteresis but agrees with GC due to the larger Abrikosov vortex density in the banks. Magnetization data on the same sample are consistent including the identification of the irreversibility field. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Gray, KE (reprint author), Argonne Natl Lab, Bldg 223, Argonne, IL 60439 USA. NR 18 TC 9 Z9 9 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 1397 EP 1400 DI 10.1016/S0921-4534(00)00956-4 PN 3 PG 4 WC Physics, Applied SC Physics GA 382YX UT WOS:000165855900002 ER PT J AU Holzapfel, B Verebelyi, D Cantoni, C Paranthaman, M Sales, B Feenstra, R Christen, D Norton, DP AF Holzapfel, B Verebelyi, D Cantoni, C Paranthaman, M Sales, B Feenstra, R Christen, D Norton, DP TI Low angle grain boundary transport properties of undoped and doped Y123 thin film bicrystals SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID YBA2CU3O7-DELTA; CALCIUM AB Undoped and Ca- or Ag-doped YBa2Cu3Ox (Y123) thin films were prepared by pulsed laser deposition on symmetric low angle SrTiO3 bicrystals (4, 8, 12, 16 degree misorientation angle). The electrical transport properties of the inter- and intragrain critical current densities and V-I curves were investigated at 77K in magnetic fields up to 6T. Ca-doped Y123 bicrystal films (10 % Ca substitution) showed no significant j(c)-enhancement at 77K in zero field but a strongly decreased j(c) at higher magnetic fields due to a reduced irreversibility field at 77K. Ag-doped Y123 bicrystal films showed increased critical current densities at higher fields and a slightly shifted transition from strong to weak link behavior compared to undoped Y123 bicrystal films. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. IFW Dresden, Inst Metall Mat, D-01171 Dresden, Germany. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Holzapfel, B (reprint author), Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RI Holzapfel, Bernhard/D-3669-2009; Paranthaman, Mariappan/N-3866-2015; Cantoni, Claudia/G-3031-2013 OI Paranthaman, Mariappan/0000-0003-3009-8531; Cantoni, Claudia/0000-0002-9731-2021 NR 10 TC 20 Z9 21 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 1431 EP 1434 DI 10.1016/S0921-4534(00)00973-4 PN 3 PG 4 WC Physics, Applied SC Physics GA 382YX UT WOS:000165855900010 ER PT J AU Latyshev, YI Pavlenko, VN Kim, SJ Yamashita, T Bulaevskii, LN Graf, MJ Balatsky, AV Morozov, N Maley, MP AF Latyshev, YI Pavlenko, VN Kim, SJ Yamashita, T Bulaevskii, LN Graf, MJ Balatsky, AV Morozov, N Maley, MP TI Interlayer tunneling of quasiparticles and Cooper pairs in Bi-2212 single crystal whiskers SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID T-C; OVERDOPED BI2SR2CACU2O8+DELTA; GAP; SUPERCONDUCTORS; PSEUDOGAP; JUNCTIONS; STACKS AB The interlayer tunneling has been studied on high quality Bi-2212 stacks of micron to the submicron lateral size. We found that low temperature and low voltage tunneling I-V characteristics can be self-consistently described by Fermi-liquid model for a d-wave superconductor with a significant contribution from coherent interlayer tunneling. The gap and pseudogap interplay with variation of temperature and magnetic field has been extracted from the I-V characteristics. We consider also the role of charging effects for submicron stacks. C1 Russian Acad Sci, Inst Radioengn & Elect, Moscow 103907, Russia. Tohoku Univ, Elect Commun Res Inst, Aoba Ku, Sendai, Miyagi 9808577, Japan. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Latyshev, YI (reprint author), Russian Acad Sci, Inst Radioengn & Elect, 11 Mokhovaya Str, Moscow 103907, Russia. NR 17 TC 6 Z9 6 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 NOV PY 2000 VL 341 BP 1499 EP 1502 DI 10.1016/S0921-4534(00)01313-7 PN 3 PG 4 WC Physics, Applied SC Physics GA 382YX UT WOS:000165855900039 ER PT J AU Koshelev, AE Bulaevskii, LN AF Koshelev, AE Bulaevskii, LN TI Josephson coupling and plasma resonance in a vortex crystal SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID INTERLAYER PHASE COHERENCE; LAYERED SUPERCONDUCTORS; STATE; BI2SR2CACU2O8+DELTA; SYSTEMS; FIELDS AB We investigate the magnetic field dependence of the plasma resonance frequency in the vortex crystal state. We find that low magnetic fields induce a small correction to the plasma frequency proportional to the field. The slope of this linear field dependence is directly related to the average distance between the pancake vortices in the neighboring layers, the wandering length. This length is determined by both Josephson and magnetic couplings between layers. At higher fields the plasma frequency is suppressed collectively and is determined by the elastic energy of the vortex lattice. Analyzing experimental data, we find that (i) the wandering length becomes comparable with the London penetration depth near T-c, (ii) at small melting fields (< 20 G) the wandering length does not change noticeably at the melting transition, demonstrating the existence of the line liquid phase in this field range, and (iii) the self consistent theory of pancake fluctuations describes very well the field dependence of the Josephson plasma resonance frequency up to the melting point. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Koshelev, AE (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Koshelev, Alexei/K-3971-2013 OI Koshelev, Alexei/0000-0002-1167-5906 NR 16 TC 12 Z9 12 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 NOV PY 2000 VL 341 BP 1503 EP 1506 DI 10.1016/S0921-4534(00)01314-9 PN 3 PG 4 WC Physics, Applied SC Physics GA 382YX UT WOS:000165855900040 ER PT J AU Tamegai, T Ueno, T Kameda, N Tokunaga, M Wang, YM Zettl, A AF Tamegai, T Ueno, T Kameda, N Tokunaga, M Wang, YM Zettl, A TI Josephson plasma resonance in Bi2Sr2CaCu2O8+y crystals with macroscopic inhomogeneities SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID COLUMNAR DEFECTS; VORTEX LIQUID; STATE; SUPERCONDUCTORS AB The Josephson plasma resonance (JPR) is studied in Bi2Sr2CaCu2O8+y (BSCCO) crystals with macroscopic inhomogeneities, which are introduced by two methods; fabricating the crystal in the form having arrays of mesa structures (20x20 mum(2) similar to 100x100 mum(2)) or by irradiating heavy-ions in half of the crystal. The JPR in BSCCO with mesa array shows an additional resonance peak indicating that the length scale where phase coherence is averaged is smaller than the size of the mesas. On the other hand, the resonance fields in the half-irradiated BSCCO and those after cutting the crystal into two are different, suggesting the presence of some kind of interference between regions which have different macroscopically averaged phase coherence properties. C1 Univ Tokyo, Dept Appl Phys, Bunkyo Ku, Tokyo 1138656, Japan. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Tamegai, T (reprint author), Univ Tokyo, Dept Appl Phys, Bunkyo Ku, 7-3-1 Hongo, Tokyo 1138656, Japan. RI Tamegai, Tsuyoshi /C-6656-2011; Tokunaga, Masashi/C-6821-2014; Zettl, Alex/O-4925-2016 OI Tokunaga, Masashi/0000-0002-1401-9381; Zettl, Alex/0000-0001-6330-136X NR 12 TC 4 Z9 4 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 NOV PY 2000 VL 341 BP 1507 EP 1510 DI 10.1016/S0921-4534(00)01315-0 PN 3 PG 4 WC Physics, Applied SC Physics GA 382YX UT WOS:000165855900041 ER PT J AU Morozov, N Krusin-Elbaum, L Shibauchi, T Bulaevskii, LN Maley, MP Latyshev, YI Yamashita, T AF Morozov, N Krusin-Elbaum, L Shibauchi, T Bulaevskii, LN Maley, MP Latyshev, YI Yamashita, T TI C-axis tunneling in Bi2Sr2CaCu2O8+delta in the magnetic field up to 60 T SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID ZERO-TEMPERATURE LIMIT; SINGLE-CRYSTALS; NORMAL-STATE; SPIN GAP; SUPERCONDUCTORS; TRANSPORT; VORTEX; MAGNETORESISTANCE; RESISTIVITIES; DISSIPATION AB We report on the c-axis resistivity rho (c)(H) in Bi2Sr2CaCu2O8+delta (Bi-2212) that exhibits a maximum in quasistatic magnetic fields up to 60 T. We show that below T-c c-asis tunneling is a parallel, two-channel process: (i) sigma (j) of Cooper pairs and (ii) sigma (q) of quasiparticles: sigma (c) = sigma (j) + sigma (q). We demonstrate that high-field c-axis conductivity is linear-in-field at H < H-c2, in agreement with the field-linear dependence of quasiparticle conductivity (q) we find in mesas. Near GO T, as temperature decreases, rho (c) saturates, confirming a gapless spectrum of quasiparticles. The linear rho (c)(H) behavior extends up to the maximum field in experiment (GOT), beyond the applicability of the Fermi-liquid approach, which can be due to effects of the pseudo gap, not accounted in the model. C1 Univ Calif Los Alamos Natl Lab, MST STC, Los Alamos, NM 87545 USA. IBM Corp, Thomas J Watson Res Ctr, Yorktown Heights, NY 10598 USA. Tohoku Univ, RIEC, Aoba Ku, Sendai, Miyagi 9808577, Japan. RP Morozov, N (reprint author), Univ Calif Los Alamos Natl Lab, MST STC, MS K763, Los Alamos, NM 87545 USA. RI Shibauchi, Takasada/B-9349-2008 OI Shibauchi, Takasada/0000-0001-5831-4924 NR 24 TC 6 Z9 6 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 NOV PY 2000 VL 341 BP 1511 EP 1514 DI 10.1016/S0921-4534(00)01316-2 PN 3 PG 4 WC Physics, Applied SC Physics GA 382YX UT WOS:000165855900042 ER PT J AU Preis, C Helm, C Schmalzl, K Walter, C Keller, J AF Preis, C Helm, C Schmalzl, K Walter, C Keller, J TI Microscopic theory of the coupling of intrinsic Josephson oscillations and phonons SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID SUBGAP STRUCTURES; SINGLE-CRYSTALS; SUPERCONDUCTORS; JUNCTIONS; TL2BA2CA2CU3O10+DELTA; BI2SR2CACU2O8+DELTA AB A microscopic theory for the coupling: of intrinsic Josephson oscillations and dispersive phonon branches in layered superconductors is developed. Thereby the effect of phonons on the electronic c-axis transport enters through an effective longitudinal dielectric function. This coupling: provides an explanation of recently observed subgap resonances in the I-dc-V-dc-curve of anisotropic cuprate superconductors forming a stack of short Josephson junctions. Due to the finite dispersion these resonances can appear at van-Hove-singularities of both optical and acoustical phonon branches, explaining low-voltage structures in the I-V-characteristic, which are not understood in phonon models without dispersion. In long junctions the dispersion of collective eletron-phonon modes parallel to the layers is investigated. C1 Univ Regensburg, Inst Theoret Phys, D-93040 Regensburg, Germany. Univ Calif Los Alamos Natl Lab, Div T11, Los Alamos, NM 87545 USA. RP Preis, C (reprint author), Univ Regensburg, Inst Theoret Phys, D-93040 Regensburg, Germany. NR 14 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 1543 EP 1546 DI 10.1016/S0921-4534(00)01329-0 PN 3 PG 4 WC Physics, Applied SC Physics GA 382YX UT WOS:000165855900050 ER PT J AU Greene, LH Aprili, M Covington, M Badica, E Pugel, DE Aubin, H Xia, YM Salamon, MB Jain, S Hinks, DG AF Greene, LH Aprili, M Covington, M Badica, E Pugel, DE Aubin, H Xia, YM Salamon, MB Jain, S Hinks, DG TI Spectroscopy of the Andreev bound state of high-temperature superconductors: Measurements of quasiparticle scattering, anisotropy and broken time-reversal symmetry SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID D-WAVE SUPERCONDUCTORS; YBA2CU3O7 THIN-FILMS; TUNNELING SPECTROSCOPY; ORDER PARAMETERS; SURFACE; JUNCTIONS; COEXISTENCE; DEPENDENCE AB Tunneling and electron paramagnetic resonance (EPR) spectroscopies are used to investigate the quasiparticle (QP) density of states (DoS) of high-temperature superconductors. Planar tunnel junctions are formed on oriented thin films of Y1Ba2Cu3O7 (YBCO) and single crystals of Ba2Sr2Ca1Cu2O8 (BSCCO). Data are obtained as a function of crystallographic orientation, temperature, doping, damage and applied magnetic field. These data demonstrate that the observed zero bias conductance peak (ZBCP) is composed of Andreev bound states (ABS) which nucleate at an ab-plane interface of a d-wave symmetry superconductor. Tunneling into doped or ion-damaged YBCO shows that the ZBCP is weakened at the same rate as the gap-like feature, and provides a measure of the QP scattering rate below T-c. An applied field causes a splitting of the ZBCP, which is due to a Doppler shift arising from the scaler product between the QP velocity and superfluid momentum, V-F.P-S The dramatic hysteresis observed with increasing and decreasing applied field is consistent with the effects of strong vortex pinning at or near the interface. The magnitude of the splitting is strongly dependent on the direction of the applied magnetic field, demonstrating the highly-anisotropic transport properties of the ABS. In-plane tunneling into single crystal BSCCO also demonstrates crystallographic orientation dependence expected for a d-wave symmetry order parameter (OP). Temperature dependence in zero applied magnetic field shows the ZBCP splits below similar to 8K, consistent with a phase transition into a superconducting state with spontaneously-broken time-reversal symmetry (BTRS). Electron paramagnetic resonance (EPR) experiments are used to directly detect the spontaneous formation of the magnetic moments in the BTRS state. C1 Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Argonne Natl Lab, Div Sci Mat, Argonne, IL 60439 USA. RP Greene, LH (reprint author), Univ Illinois, Dept Phys, Urbana, IL 61801 USA. NR 25 TC 1 Z9 1 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 1633 EP 1637 DI 10.1016/S0921-4534(00)01490-8 PN 3 PG 5 WC Physics, Applied SC Physics GA 382YX UT WOS:000165855900085 ER PT J AU Klemm, RA Arnold, G Bille, A Scharnberg, K AF Klemm, RA Arnold, G Bille, A Scharnberg, K TI Theory of c-axis twist Bi2212 Josephson junctions: Strong evidence for incoherent tunneling and s-wave superconductivity SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS AB We studied the Bi2Sr2 CaCu2O8+delta bicrystal c-axis twist junctions of Li et al. In one model, two coherent tight-binding layered superconductors are coupled across the twist via coherent c-axis tunneling. In the other model, the c-axis tunneling across the twist is a Gaussian in the momentum change across the junction. We conclude that the c-axis tunneling is strongly incoherent, and contains an isotropic s-wave component for T less than or equal to T-c. C1 Argonne Natl Lab, Div Sci Mat, Argonne, IL 60439 USA. Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. Univ Hamburg, Fachbereich Phys, D-20355 Hamburg, Germany. RP Klemm, RA (reprint author), Argonne Natl Lab, Div Sci Mat, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 5 TC 2 Z9 2 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 NOV PY 2000 VL 341 BP 1663 EP 1664 DI 10.1016/S0921-4534(00)00925-4 PN 3 PG 2 WC Physics, Applied SC Physics GA 382YX UT WOS:000165855900092 ER PT J AU Li, Q Tsay, YN Suenaga, M Gu, GD Koshizuka, N AF Li, Q Tsay, YN Suenaga, M Gu, GD Koshizuka, N TI A direct probe of superconducting order parameter symmetry in Bi2Sr2CaCu2O8+delta using bicrystal c-axis twist Josephson junctions SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID BOUNDARIES AB Atomically clean Bi2Sr2CaCu2O8+delta (Bi2212) bicrystal grain boundary junctions were prepared using identical single crystal cleaves stacked and twisted an arbitrary angle phi (0) about the c-axis. We show that for each bicrystal, regardless of phi (0), the ratio of the measured c-axis Josephson critical current density across the twist junction to that across either single crystal part (J(c)(J)/J(c)(S)) is close to unity for T less than or equal to T-c. This result provides evidence that an isotropic s-wave superconducting order parameter is present near T-c . C1 Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. ISTEC, Superconduct Res Lab, Tokyo 135, Japan. RP Li, Q (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. NR 4 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 1665 EP 1666 DI 10.1016/S0921-4534(00)00926-6 PN 3 PG 2 WC Physics, Applied SC Physics GA 382YX UT WOS:000165855900093 ER PT J AU Aubin, H Pugel, DE Badica, E Greene, LH Jain, S Hinks, DG AF Aubin, H Pugel, DE Badica, E Greene, LH Jain, S Hinks, DG TI In-plane quasi-particle tunneling into Bi2Sr2CaCu2O8 SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID ANDREEV BOUND-STATES; SURFACE; JUNCTIONS AB Planar tunneling spectroscopy is performed into the a-b plane of the high-temperature superconductor Bi2Sr2CaCu2O8. The tunneling spectra exhibit a zero-bias conductance peak (ZBCP). Preliminary studies as a function of temperature, crystallographic orientation, magnetic field magnitude and direction confirm the ZBCP is an Andreev bound state (ABS) at zero energy. Below 5K, a depletion in the density of states at zero energy is observed. C1 Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Argonne Natl Lab, Div Sci Mat, Argonne, IL 60439 USA. RP Aubin, H (reprint author), Univ Illinois, Dept Phys, Urbana, IL 61801 USA. NR 6 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 1681 EP 1682 DI 10.1016/S0921-4534(00)00934-5 PN 3 PG 2 WC Physics, Applied SC Physics GA 382YX UT WOS:000165855900101 ER PT J AU Haase, J Slichter, CP Stern, R Milling, CT Hinks, DG AF Haase, J Slichter, CP Stern, R Milling, CT Hinks, DG TI Spatial modulation of the NMR properties of the cuprates SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID T-J MODEL; NEUTRON-SCATTERING; LA2-XSRXCUO4; LA1.85SR0.15CUO4; SUPERCONDUCTORS AB Substantial temperature dependent spatial modulation of the O and Cu NMR parameters of La1.85Sr0.15CuO4 from 10 K to 300K are reported. The length scale of the modulations is only a few lattice distances. Analysis of the planar oxygen lineshape shows that modulations of the Knight shift and quadrupole coupling are correlated. The Cu spectra reveal a strong modulation of chemical shift. Similar results on other cuprates indicate universality of these phenomena. C1 Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Univ Illinois, Mat Res Lab, Urbana, IL 61801 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Univ Stuttgart, Inst Phys 2, D-70569 Stuttgart, Germany. RP Haase, J (reprint author), Univ Illinois, Dept Phys, 1110 W Green St, Urbana, IL 61801 USA. RI Stern, Raivo/A-5387-2008 OI Stern, Raivo/0000-0002-6724-9834 NR 17 TC 25 Z9 25 U1 1 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 NOV PY 2000 VL 341 BP 1727 EP 1730 DI 10.1016/S0921-4534(00)00952-7 PN 3 PG 4 WC Physics, Applied SC Physics GA 382YX UT WOS:000165855900119 ER PT J AU Eroles, J Ortiz, G Balatsky, AV Bishop, AR AF Eroles, J Ortiz, G Balatsky, AV Bishop, AR TI Microscopic scenario for striped superconductors SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS AB We argue that the superconducting state found in high-T-c cuprates is inhomogeneous with a corresponding inhomogeneous superfluid density. We introduce two classes of microscopic models which capture the magnetic and superconducting properties of these strongly correlated materials. We start from a generalized t-J model, in which appropriate inhomogeneous terms mimic stripes. We find that inhomogeneous interactions that break magnetic symmetries are essential to induce substantial pair binding of holes in the thermodynamic limit. We argue that this type of model reproduces the ARPES and neutron scattering data seen experimentally. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Ctr Atom Bariloche, RA-8400 Bariloche, Rio Negro, Argentina. Inst Balseiro, RA-8400 Bariloche, Rio Negro, Argentina. RP Eroles, J (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 4 TC 1 Z9 1 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 NOV PY 2000 VL 341 BP 1763 EP 1766 DI 10.1016/S0921-4534(00)01011-X PN 3 PG 4 WC Physics, Applied SC Physics GA 382YX UT WOS:000165855900128 ER PT J AU Bozin, ES Billinge, SJL Kwei, GH Takagi, H AF Bozin, ES Billinge, SJL Kwei, GH Takagi, H TI Local structural evidence for inhomogeneous charge distribution in CuO2 planes of superconducting La2-xSTxCuO4 SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS AB Local structural evidence is found supporting the presence of charge inhomogeneities in the CuO2 planes of underdoped La2-xSrxCuO4, using high-resolution PDF analysis of neutron powder diffraction data. Broadening of the in-plane Cu-O bond distribution as a function of doping up to optimal doping is observed. Thereafter the peak abruptly sharpens. The result suggests a crossover from a charge inhomogeneous state below optimal doping to a homogeneous charge state above optimal doping. C1 Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. Michigan State Univ, Ctr Fundamental Mat Res, E Lansing, MI 48824 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Tokyo, Inst Solid State Phys, Minato Ku, Tokyo 106, Japan. RP Bozin, ES (reprint author), Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. RI Takagi, Hidenori/B-2935-2010; Bozin, Emil/E-4679-2011 NR 4 TC 7 Z9 7 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 NOV PY 2000 VL 341 BP 1793 EP 1794 DI 10.1016/S0921-4534(00)01074-1 PN 3 PG 2 WC Physics, Applied SC Physics GA 382YX UT WOS:000165855900139 ER PT J AU Curro, NJ Hammel, PC AF Curro, NJ Hammel, PC TI The CuNMR echo decay in stripe ordered La1.65Eu0.2Sr0.15CuO4 SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID SUPERCONDUCTORS; RELAXATION; HOLES; SPINS AB The Cu NMR echo decay in rare earth co-doped lanthanum cuprate undergoes a crossover from Gaussian to exponential decay below T similar to 100K. This behavior indicates that the visible nuclei are coupled to others with much faster spin lattice relaxation rates. We interpret the NMR signal as arising solely from regions on the boundaries of large clusters of coupled electron spins. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Curro, NJ (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Hammel, P Chris/O-4845-2014; Curro, Nicholas/D-3413-2009 OI Hammel, P Chris/0000-0002-4138-4798; Curro, Nicholas/0000-0001-7829-0237 NR 7 TC 4 Z9 4 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 1797 EP 1798 DI 10.1016/S0921-4534(00)01084-4 PN 3 PG 2 WC Physics, Applied SC Physics GA 382YX UT WOS:000165855900141 ER PT J AU Phillips, NE Fisher, RA Emerson, JP Gordon, JE Woodfield, BF Wright, DA AF Phillips, NE Fisher, RA Emerson, JP Gordon, JE Woodfield, BF Wright, DA TI Specific heat of YBa2Cu3O7-delta: paramagnetic centers; evidence for line nodes in the energy gap SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID DENSITY-OF-STATES; D-WAVE SUPERCONDUCTORS; MAGNETIC-FIELD DEPENDENCE; TEMPERATURE SPECIFIC-HEAT; BASAL-PLANE; MIXED-STATE; 0-LESS-THAN-OR-EQUAL-TO-DELTA-LESS-THAN-OR-EQUAL-TO-0.2; VORTEX AB Specific-heat data on YBa2Cu3O7-delta, 0 < < 0.2, have been analyzed to show the presence of spin-2, as well as spin-1/2, paramagnetic centers. Evidence of line nodes in the energy gap, including conformity to a predicted scaling relation, is reported. C1 Lawrence Berkeley Natl, Berkeley, CA 94720 USA. Dept Chem, Berkeley, CA 94720 USA. Amherst Coll, Dept Phys, Amherst, MA 01002 USA. Brigham Young Univ, Dept Chem & Biochem, Provo, UT 84602 USA. RP Phillips, NE (reprint author), Lawrence Berkeley Natl, Berkeley, CA 94720 USA. NR 18 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 1805 EP 1808 DI 10.1016/S0921-4534(00)01093-5 PN 3 PG 4 WC Physics, Applied SC Physics GA 382YX UT WOS:000165855900143 ER PT J AU Boaknin, E Hill, RW Lupien, C Taillefer, L Canfield, PC AF Boaknin, E Hill, RW Lupien, C Taillefer, L Canfield, PC TI Heat conduction in the borocarbide superconductor LuNi2B2C SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID THERMAL-CONDUCTIVITY; SINGLE-CRYSTALS; LU AB The thermal conductivity of the borocarbide superconductor LuNi2B2C (T-c = 16 K) was measured in the temperature range from 50 mK to 100 K. An unusually large phonon peak is observed in the superconducting state and the data at very low temperature is consistent with this material being an s-wave superconductor. C1 Univ Toronto, Dept Phys, Toronto, ON M5S 1A7, Canada. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Boaknin, E (reprint author), Univ Toronto, Dept Phys, 60 St George St, Toronto, ON M5S 1A7, Canada. RI Lupien, Christian/C-2148-2008; Canfield, Paul/H-2698-2014 OI Lupien, Christian/0000-0003-1767-8603; NR 14 TC 17 Z9 17 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 1845 EP 1848 DI 10.1016/S0921-4534(00)01117-5 PN 3 PG 4 WC Physics, Applied SC Physics GA 382YX UT WOS:000165855900153 ER PT J AU Balakirev, FF Ando, Y Passner, A Betts, JB Schneemeyer, LF Segawa, K Boebinger, S AF Balakirev, FF Ando, Y Passner, A Betts, JB Schneemeyer, LF Segawa, K Boebinger, S TI Large, linear c-axis magnetoresistance in YBa2Cu3O7-delta SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID OF-PLANE MAGNETORESISTANCE; SINGLE-CRYSTALS; NEGATIVE MAGNETORESISTANCE; LA2-XSRXCUO4; RESISTIVITY; INPLANE AB Underdoped YBa2Cu3O7-delta Single crystals exhibit a large, positive c-axis magnetoresistance that is strikingly linear over a wide magnetic field range up to 60 T. This linear magnetoresistance is observed at temperatures near or below T-c, once sufficient magnetic field has been applied to suppress superconductivity. The measurements are done in the longitudinal geometry, with current and magnetic field both along the c-axis (I\\B\\c). The linear magnetoresistance can be large, giving as much as a 35% increase in resistance between 30 T and 60 T. It also exhibits very strong temperature dependence, increasing by as much as an order of magnitude as the temperature is reduced from 100 K to 10 K. C1 Univ Calif Los Alamos Natl Lab, NHMFL, Los Alamos, NM 87545 USA. Cent Res Inst Elect Power Ind, Tokyo 2018511, Japan. Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. RP Balakirev, FF (reprint author), Univ Calif Los Alamos Natl Lab, NHMFL, POB 1663, Los Alamos, NM 87545 USA. RI Ando, Yoichi/B-8163-2013; SEGAWA, Kouji/D-4204-2014 OI Ando, Yoichi/0000-0002-3553-3355; SEGAWA, Kouji/0000-0002-3633-4809 NR 10 TC 4 Z9 4 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 1877 EP 1878 DI 10.1016/S0921-4534(00)01236-3 PN 3 PG 2 WC Physics, Applied SC Physics GA 382YX UT WOS:000165855900168 ER PT J AU Cimpoiasu, E Levin, GA Almasan, CC Zheng, H Veal, BW AF Cimpoiasu, E Levin, GA Almasan, CC Zheng, H Veal, BW TI Magnetoresistivity in strongly underdoped YBa2Cu3Ox single crystals SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS AB We report magnetoresistivity measurements on Y Ba2Cu3O6.36 Single crystals in applied magnetic fields H||c up to 14 T. We observe several unusual features: the out-of-plane magnetoresistivity np,lp, is negative at high temperatures T and becomes positive for T < 150 K. The in-plane magnetoresistivity rho (ab)/rho (ab) is positive and displays a maximum at T approximate to 180 K. There is a direct correlation between the sign and T-dependence of magnetoresistivities and the corresponding temperature coefficients of resistivities; i.e. Delta rho (c,ab) similar to d rho (c,ab)/dT over the measured T range for the in-plane component and for T > 150 K for the out-of-plane component. C1 Kent State Univ, Dept Phys, Kent, OH 44242 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP Cimpoiasu, E (reprint author), Kent State Univ, Dept Phys, Kent, OH 44242 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 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 1879 EP 1880 DI 10.1016/S0921-4534(00)01237-5 PN 3 PG 2 WC Physics, Applied SC Physics GA 382YX UT WOS:000165855900169 ER PT J AU Radovan, HA Behne, E Zieve, RJ Kim, JS Stewart, GR Kwok, WK AF Radovan, HA Behne, E Zieve, RJ Kim, JS Stewart, GR Kwok, WK TI Reduction of critical temperatures in pure and thoriated UBe13 by columnar defects SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID PHASE-DIAGRAM; U1-XTHXBE13 AB We investigate the influence of columnar defects on the superconducting transition temperatures of UBe13 and U0.97Th0.03Be13 The defects cause all the transitions to widen and to drop slightly in temperature. Quantitatively, the lower transition in U0.97Th0.03Be13 more strongly resembles the single UBe13 transition. C1 Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Univ Florida, Dept Phys, Gainesville, FL 32611 USA. Argonne Natl Lab, Div Sci Mat, Argonne, IL 60435 USA. RP Radovan, HA (reprint author), Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. NR 6 TC 1 Z9 1 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 1953 EP 1954 DI 10.1016/S0921-4534(00)01420-9 PN 3 PG 2 WC Physics, Applied SC Physics GA 382YX UT WOS:000165855900206 ER PT J AU Naugle, DG Rathnayaka, KDD Parasiris, A Canfield, PC AF Naugle, DG Rathnayaka, KDD Parasiris, A Canfield, PC TI Transport properties of HoxDy1-xNi2B2C single crystals SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID INTERPLAY; HONI2B2C AB The Neel temperature (T-N) of the magnetic superconductor HoNi2B2C is below its superconducting transition temperature [1] (T-c) while DyNi2B2C becomes superconducting below the magnetic ordering temperature [2] (T-c < T-N) HoxDy1-xNi2B2C demonstrates a rich interplay between superconductivity and magnetism as x is increased. Transport properties and the magnetic/superconducting phase diagram of single crystal HoxDy1-xNi2B2C are reported for different values of x. C1 Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Naugle, DG (reprint author), Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. RI Canfield, Paul/H-2698-2014 NR 5 TC 1 Z9 1 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 NOV PY 2000 VL 341 BP 1959 EP 1960 DI 10.1016/S0921-4534(00)01423-4 PN 3 PG 2 WC Physics, Applied SC Physics GA 382YX UT WOS:000165855900209 ER PT J AU Norman, MR Randeria, M Janko, B Campuzano, JC AF Norman, MR Randeria, M Janko, B Campuzano, JC TI Photoemission and the origin of high temperature superconductivity SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TX ID T-C; MECHANISM; SPECTRA AB The condensation energy can be shown to be a moment of the change in the occupied part of the spectral function when going from the normal to the superconducting state. As a consequence, there is a one to one correspondence between the energy gain associated with forming the superconducting ground state, and the dramatic changes seen in angle resolved photoemission spectra. Some implications this observation has are offered. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Tata Inst Fundamental Res, Bombay 400005, Maharashtra, India. Univ Illinois, Dept Phys, Chicago, IL 60607 USA. RP Norman, MR (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Norman, Michael/C-3644-2013 NR 19 TC 0 Z9 0 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 NOV PY 2000 VL 341 BP 2063 EP 2066 DI 10.1016/S0921-4534(00)01035-2 PN 4 PG 4 WC Physics, Applied SC Physics GA 382YY UT WOS:000165856000001 ER PT J AU Fujimori, A Ino, A Yoshida, T Mizokawa, T Nakamura, M Kim, C Shen, ZX Kakeshita, T Eisaki, H Uchida, S AF Fujimori, A Ino, A Yoshida, T Mizokawa, T Nakamura, M Kim, C Shen, ZX Kakeshita, T Eisaki, H Uchida, S TI Fermi surface, pseudogap and superconducting gap in La2-xSrxCuO4 SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID ELECTRONIC-STRUCTURE; BI2SR2CACU2O8+DELTA; EVOLUTION; DENSITY; STATE AB The electronic structure of La2-xSrxCuO4 (LSCO) has been revealed by a series of photoemission spectroscopic studies. The unusual electronic states in the underdoped regime are attributed to the large and small pseudogap formation, which has been observed in other high-T-C cuprates, and stripe fluctuations, which are particularly pronounced in LSCO. C1 Univ Tokyo, Dept Phys, Bunkyo Ku, Tokyo 1130033, Japan. Univ Tokyo, Dept Complex Sci & Engn, Bunkyo Ku, Tokyo 1130033, Japan. Japan Atom Energy Res Inst, Sayo, Hyogo 6795198, Japan. Nara Univ Educ, Dept Phys, Nara 6308528, Japan. Stanford Univ, Dept Appl Phys, Stanford, CA 94305 USA. Stanford Univ, Stanford Synchrotron Radiat Lab, Stanford, CA 94305 USA. Univ Tokyo, Dept Superconduct, Bunkyo Ku, Tokyo 1138656, Japan. Univ Tokyo, Dept Adv Mat Sci, Bunkyo Ku, Tokyo 1130033, Japan. RP Fujimori, A (reprint author), Univ Tokyo, Dept Phys, Bunkyo Ku, Tokyo 1130033, Japan. RI Mizokawa, Takashi/E-3302-2015 OI Mizokawa, Takashi/0000-0002-7682-2348 NR 17 TC 12 Z9 12 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 2067 EP 2070 DI 10.1016/S0921-4534(00)01040-6 PN 4 PG 4 WC Physics, Applied SC Physics GA 382YY UT WOS:000165856000002 ER PT J AU Sato, T Naitoh, Y Kamiyama, T Takahashi, T Yokoya, T Mesot, J Kaminski, A Fretwell, H Campuzano, JC Ding, H Chong, I Terashima, T Takano, M Kadowaki, K AF Sato, T Naitoh, Y Kamiyama, T Takahashi, T Yokoya, T Mesot, J Kaminski, A Fretwell, H Campuzano, JC Ding, H Chong, I Terashima, T Takano, M Kadowaki, K TI Superconducting gap, pseudogap, and fermi surface of Bi2201: High energy- and momentum-resolution photoemission study SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID ANGLE-RESOLVED PHOTOEMISSION; T-C SUPERCONDUCTORS; ELECTRONIC-STRUCTURE; NORMAL-STATE; BI2SR2CACU2O8+DELTA; ANISOTROPY; PLANE AB We have performed a systematic high energy (7-11 meV) and momentum (0.01 Angstrom (-1)) resolution angle-resolved photoemission spectroscopy (ARPES) on superstructure-free Bi1.80Pb0.38Sr2.01CuO6-delta With various dopings. All the samples from overdoped T-c=0K to underdoped T-c=18K possess a large hole-like Fermi surface centered at X point, whose volume shows a systematic evolution with doping. The superconducting gap exhibits a d(x2-y2)-like anisotropy with a typical gap value of 10-15 meV. By comparing with Bi2Sr2CaCu2O8, we found that the size of superconducting gap and the ARPES spectral feature near EF are well scaled with the maximum T-c (T-c(max)). This suggests that the superconducting properties are characterized by T-c(max) irrespective of the number of CuO2 layers or the structural modulation in BiO layer. C1 Tohoku Univ, Dept Phys, Sendai, Miyagi 9808578, Japan. Univ Tokyo, Inst Solid State Phys, Kashiwa, Chiba 2778581, Japan. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Univ Illinois, Dept Phys, Chicago, IL 60607 USA. Boston Coll, Dept Phys, Chestnut Hill, MA 02467 USA. Kyoto Univ, Inst Chem Res, Uji, Kyoto 6110011, Japan. Univ Tsukuba, Inst Mat Sci, Tsukuba, Ibaraki 3053573, Japan. RP Sato, T (reprint author), Tohoku Univ, Dept Phys, Sendai, Miyagi 9808578, Japan. RI Sato, Takafumi/E-5094-2010; Tohoku, Arpes/A-4890-2010; Takahashi, Takashi/E-5080-2010; YOKOYA, Takayoshi/B-1478-2011 NR 17 TC 2 Z9 2 U1 2 U2 11 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 2091 EP 2094 DI 10.1016/S0921-4534(00)01099-6 PN 4 PG 4 WC Physics, Applied SC Physics GA 382YY UT WOS:000165856000008 ER PT J AU Suh, BJ Hammel, PC AF Suh, BJ Hammel, PC TI La-139 NQR and NMR studies of the structural phase transitions in La1.8-xEu0.2SrxCuO4 SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID SUPERCONDUCTIVITY AB La-139 NQR and NMR relaxation measurements in the til;le compound have been used to investigate the dynamical properties of the structural phase transitions (SPT): HTT --> LTO and LTO --> LTT of lathanum cuprate. We present the data for thermodynamic fluctuations of critical modes in the vicinity of the SPT's which clearly reveal the character of each SPT and its dependence on doped hole concentration. C1 Catholic Univ Korea, Dept Phys, Puchon, South Korea. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Suh, BJ (reprint author), Catholic Univ Korea, Dept Phys, Puchon, South Korea. RI Hammel, P Chris/O-4845-2014 OI Hammel, P Chris/0000-0002-4138-4798 NR 9 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 2127 EP 2128 DI 10.1016/S0921-4534(00)01023-6 PN 4 PG 2 WC Physics, Applied SC Physics GA 382YY UT WOS:000165856000021 ER PT J AU Gutmann, M Billinge, SJL Brosha, E Kwei, GH AF Gutmann, M Billinge, SJL Brosha, E Kwei, GH TI Local structural evidence for charge inhomogeneities in the CuO2 planes of YBa2Cu3O6+x x=0.25, 0.45, 0.65, 0.94 SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID SUPERCONDUCTORS AB The atomic pair distribution function (PDF) of YBa2Cu3O6+x (x=0.25, 0.45, 0.65, 0.94) at 15 K has been measured. From least-squares full-profile modeling no split position is found for the apical oxygen in contrast to earlier XAFS work. Instead, an improvement over the average crystallographic structure results for a split planar Cu(2) site. This finding supports the existence of charge inhomogeneities throughout the planes and may resolve a long-standing controversy between the XAFS and diffraction community. C1 Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Gutmann, M (reprint author), Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. NR 9 TC 0 Z9 0 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 NOV PY 2000 VL 341 BP 2143 EP 2144 DI 10.1016/S0921-4534(00)01094-7 PN 4 PG 2 WC Physics, Applied SC Physics GA 382YY UT WOS:000165856000029 ER PT J AU Suter, A Mali, M Roos, J Brinkmann, D AF Suter, A Mali, M Roos, J Brinkmann, D TI Low energy charge fluctuations in the presence of the pseudo spin gap in YBa2Cu4O8 SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS ID SUPERCONDUCTORS; OXIDES AB We present results from a O-17 nuclear magnetic resonance study in the stoichiometric superconductor YBa2Cu4O8. A double irradiation method enables us to show that, below around 180 K approximate to T*, the spin-lattice relaxation rate of plane oxygen is not only driven by magnetic, but also significantly by quadrupolar fluctuations, i.e. low-frequency charge fluctuations. From the temperature dependence as well as from the magnitude of the spin-lattice relaxation, we conclude that this low-frequency charge fluctuations are not of simple phononic or sim ple electron-like quasiparticle origin. In the superconducting state, on lowering the temperature, the quadrupolar relaxation diminishes faster than the magnetic one. On the other side, we do not observe any quadrupolar contributions in the spin-lattice relaxation of plane copper. These findings show that, with the opening of the pseudo spin gap, a charge degree of freedom of mainly oxygen character is present in the electronic low-energy excitation spectrum. Different possibilities of charge degrees could explain our findings: (i) Formation of spatially strongly correlated holes. (ii) Anomalous strong electron-phonon coupling. These findings suggest that a simple magnetic single spin fluid model is not sufficient to describe the low-energy excitations for temperatures T < T*. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Zurich, Inst Phys, CH-8057 Zurich, Switzerland. RP Suter, A (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 9 TC 0 Z9 0 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 NOV PY 2000 VL 341 BP 2167 EP 2168 DI 10.1016/S0921-4534(00)01240-5 PN 4 PG 2 WC Physics, Applied SC Physics GA 382YY UT WOS:000165856000041 ER PT J AU Mali, M Suter, A Roos, J Brinkmann, D Keller, H Karpinski, J AF Mali, M Suter, A Roos, J Brinkmann, D Keller, H Karpinski, J TI Chain charge fluctuations in YBa2Cu4O8 detected via apex oxygen nuclear quadrupolar relaxation SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS AB We report a O-17 NMR study of the apex oxygen in YBa2Cu4O8. Applying two independent methods we show that the spin-lattice relaxation rate of apex oxygen is predominantly of quadrupolar origin and is driven by charge fluctuations in the double chain. The temperature dependence of this quadrupolar relaxation is different from the temperature dependence of the magnetic relaxation of double chain copper and oxygen. This indicates a possible spin-charge separation of the charge carrier quasi-particles in the double chain quasi-one dimensional conductor. C1 Univ Zurich, Inst Phys, CH-8057 Zurich, Switzerland. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. ETH Zurich, Festkorperphys Lab, CH-8093 Zurich, Switzerland. RP Mali, M (reprint author), Univ Zurich, Inst Phys, CH-8057 Zurich, Switzerland. NR 5 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 2169 EP 2170 DI 10.1016/S0921-4534(00)01251-X PN 4 PG 2 WC Physics, Applied SC Physics GA 382YY UT WOS:000165856000042 ER PT J AU Maroni, VA Fischer, AK Wu, KT AF Maroni, VA Fischer, AK Wu, KT TI The investigation of phase evolution in composite ceramic superconductors using Raman microscopy techniques SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI CY FEB 20-25, 2000 CL HOUSTON, TEXAS AB Raman microspectroscopy and imaging techniques are being used to investigate key mechanistic features that influence the formation of layered Bi-based superconducting phases during the thermal treatment employed to produce silver-sheathed Bi-2223 composite conductors. Seminal information gained from these studies includes the identification of the constituent phases in certain nonsuperconducting second phase (NSP) agglomerations that tend to resist dissipation as high-Tc phase formation proceeds to completion. C1 Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. SUNY Coll Old Westbury, Old Westbury, NY 11568 USA. RP Maroni, VA (reprint author), Argonne Natl Lab, Div Chem Technol, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 3 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD NOV PY 2000 VL 341 BP 2243 EP 2244 DI 10.1016/S0921-4534(00)01071-6 PN 4 PG 2 WC Physics, Applied SC Physics GA 382YY UT WOS:000165856000067 ER EF