FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Allspach, D Hahn, A Kendziora, C Pordes, S Boero, G Garzoglio, G Macri, M Marinelli, M Robutti, E AF Allspach, D Hahn, A Kendziora, C Pordes, S Boero, G Garzoglio, G Macri, M Marinelli, M Robutti, E TI The variable density gas jet internal target for Experiment 835 at Fermilab SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE target; cluster; internal; storage; charmonium AB The hydrogen Jet Target for Experiment 835 (Charmonium spectroscopy) at the Fermilab Antiproton Accumulator can provide a variable density cluster stream up to 3.2 x 10(14) atoms/cm(3) in order to allow an instantaneous luminosity greater than 2 x 10(31) cm(-2) s(-1). This result can be achieved due to the helium refrigerated expansion stage which provides the cluster stream and due to the pumping and the alignment system which significantly lower the background gas. Details on the construction and the performances, measured in the laboratory and during the run, are discussed. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Genoa, I-16126 Genoa, Italy. Ist Nazl Fis Nucl, Genoa, Italy. RP Garzoglio, G (reprint author), Fermilab, MS 366,POB 500, Batavia, IL 60510 USA. EM garzogli@fnal.gov NR 13 TC 22 Z9 22 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUN 11 PY 1998 VL 410 IS 2 BP 195 EP 205 DI 10.1016/S0168-9002(98)00236-8 PG 11 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA ZZ567 UT WOS:000074743100007 ER PT J AU Bangert, PD Cooper, MD Lamoreaux, SK AF Bangert, PD Cooper, MD Lamoreaux, SK TI Enhancement of superthermal ultracold neutron production by trapping cold neutrons SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB In the production of ultracold neutrons (UCN) by scattering cold neutrons in superfluid He-4 or cold solid D-2 ("superthermal" processes), the UCN production rate is proportional to the spatial density of cold neutrons in the material. For a superthermal source fed from a cold neutron guide, we show that the rate of UCN production can be increased by up to a factor of about 2.3 for realistic substances by enclosing the source in a cavity made of a material with a high cold neutron albedo. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Cooper, MD (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 8 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUN 11 PY 1998 VL 410 IS 2 BP 264 EP 272 DI 10.1016/S0168-9002(98)00282-4 PG 9 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA ZZ567 UT WOS:000074743100014 ER PT J AU Bai, JZ Bardon, O Blum, I Breakstone, A Burnett, T Chen, GP Chen, HF Chen, J Chen, SJ Chen, SM Chen, Y Chen, YB Chen, YQ Cheng, BS Cowan, RF Cui, XZ Ding, HL Du, ZZ Dunwoodie, W Fan, XL Fang, J Fero, M Gao, CS Gao, ML Gao, SQ Gratton, P Gu, JH Gu, SD Gu, WX Gu, YF Guo, YN Han, SW Han, Y Harris, FA Hatanaka, M He, J He, M Hitlin, DG Hu, GY Hu, T Hu, XQ Huang, DQ Huang, YZ Izen, JM Jia, QP Jiang, CH Jin, S Jin, Y Jones, L Kang, SH Ke, ZJ Kelsey, MH Kim, BK Kong, D Lai, YF Lan, HB Lang, PF Lankford, A Li, F Li, J Li, PQ Li, Q Li, RB Li, W Li, WD Li, WG Li, XH Li, XN Lin, SZ Liu, HM Liu, JH Liu, Q Liu, RG Liu, Y Liu, ZA Lou, XC Lowery, B Lu, JG Luo, S Luo, Y Ma, AM Ma, EC Ma, JM Mao, HS Mao, ZP Malchow, R Mandelkern, M Meng, XC Ni, HL Nie, J Olsen, SL Oyang, J Paluselli, D Pan, LJ Panetta, J Porter, F Prabhakar, E Qi, ND Que, YK Quigley, J Rong, G Schernau, M Schmid, B Schultz, J Shao, YY Shen, DL Shen, H Shen, XY Sheng, HY Shi, HZ Shi, XR Smith, A Soderstrom, E Song, XF Standifird, J Stoker, D Sun, F Sun, HS Sun, SJ Synodinos, J Tan, YP Tang, SQ Toki, W Tong, GL Torrence, E Wang, F Wang, LS Wang, LZ Wang, M Wang, P Wang, PL Wang, SM Wang, TJ Wang, YY Wei, CL Whittaker, S Wilson, R Wisniewski, WJ Xi, DM Xia, XM Xie, PP Xu, DZ Xu, RS Xu, ZQ Xue, ST Yamamoto, R Yan, J Yan, WG Yang, CM Yang, CY Yang, W Ye, MH Ye, SZ Young, K Yu, CS Yu, XC Yu, ZQ Yuan, CZ Zhang, BY Zhang, CC Zhang, DH Zhang, HL Zhang, J Zhang, JW Zhang, LS Zhang, SQ Zhang, Y Zhang, YY Zhao, DX Zhao, HW Zhao, JW Zhao, M Zhao, WR Zheng, JP Zheng, LS Zheng, ZP Zhou, GP Zhou, HS Zhou, L Zhou, XF Zhou, YH Zhu, QM Zhu, YC Zhu, YS Zhuang, BA Zioulas, G AF Bai, JZ Bardon, O Blum, I Breakstone, A Burnett, T Chen, GP Chen, HF Chen, J Chen, SJ Chen, SM Chen, Y Chen, YB Chen, YQ Cheng, BS Cowan, RF Cui, XZ Ding, HL Du, ZZ Dunwoodie, W Fan, XL Fang, J Fero, M Gao, CS Gao, ML Gao, SQ Gratton, P Gu, JH Gu, SD Gu, WX Gu, YF Guo, YN Han, SW Han, Y Harris, FA Hatanaka, M He, J He, M Hitlin, DG Hu, GY Hu, T Hu, XQ Huang, DQ Huang, YZ Izen, JM Jia, QP Jiang, CH Jin, S Jin, Y Jones, L Kang, SH Ke, ZJ Kelsey, MH Kim, BK Kong, D Lai, YF Lan, HB Lang, PF Lankford, A Li, F Li, J Li, PQ Li, Q Li, RB Li, W Li, WD Li, WG Li, XH Li, XN Lin, SZ Liu, HM Liu, JH Liu, Q Liu, RG Liu, Y Liu, ZA Lou, XC Lowery, B Lu, JG Luo, S Luo, Y Ma, AM Ma, EC Ma, JM Mao, HS Mao, ZP Malchow, R Mandelkern, M Meng, XC Ni, HL Nie, J Olsen, SL Oyang, J Paluselli, D Pan, LJ Panetta, J Porter, F Prabhakar, E Qi, ND Que, YK Quigley, J Rong, G Schernau, M Schmid, B Schultz, J Shao, YY Shen, DL Shen, H Shen, XY Sheng, HY Shi, HZ Shi, XR Smith, A Soderstrom, E Song, XF Standifird, J Stoker, D Sun, F Sun, HS Sun, SJ Synodinos, J Tan, YP Tang, SQ Toki, W Tong, GL Torrence, E Wang, F Wang, LS Wang, LZ Wang, M Wang, P Wang, PL Wang, SM Wang, TJ Wang, YY Wei, CL Whittaker, S Wilson, R Wisniewski, WJ Xi, DM Xia, XM Xie, PP Xu, DZ Xu, RS Xu, ZQ Xue, ST Yamamoto, R Yan, J Yan, WG Yang, CM Yang, CY Yang, W Ye, MH Ye, SZ Young, K Yu, CS Yu, XC Yu, ZQ Yuan, CZ Zhang, BY Zhang, CC Zhang, DH Zhang, HL Zhang, J Zhang, JW Zhang, LS Zhang, SQ Zhang, Y Zhang, YY Zhao, DX Zhao, HW Zhao, JW Zhao, M Zhao, WR Zheng, JP Zheng, LS Zheng, ZP Zhou, GP Zhou, HS Zhou, L Zhou, XF Zhou, YH Zhu, QM Zhu, YC Zhu, YS Zhuang, BA Zioulas, G TI Evidence for the leptonic decay D ->mu nu(mu) SO PHYSICS LETTERS B LA English DT Article ID HEAVY-QUARK; POTENTIAL MODEL; MESON DECAYS; SUM-RULES; B-MESONS; CONSTANTS; QCD; LATTICE; CHARM; HADRONS AB Purely leptonic decays of the charged D meson have been studied using the reaction e(+)e(-) --> D*D-+(-) at a center of mass energy of 4.03 GeV. A search was performed for D --> mu v(mu), recoiling against a D-0 or D+ which had been reconstructed from its hadronic decay products. A single event candidate was found in the reaction e(+)e(-) --> D*D-+(-), where D*(+) --> pi(+)D(0) with the D-0 --> K- pi(+), and the recoiling D- decaying via D- --> mu(-)(v) over bar(mu). This yields a branching fraction value (D --> mu v mu) = 0.08(- 0.05 - 0.02)(+ 0.16 + 0.05)% and a corresponding value of the pseudoscalar decay constant f(D) = 300(- 150 - 40)(+ 180 + 80) MeV. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Inst High Energy Phys, Beijing 100039, Peoples R China. Boston Univ, Boston, MA 02215 USA. CALTECH, Pasadena, CA 91125 USA. Univ Sci & Technol China, Hefei 230026, Peoples R China. Colorado State Univ, Ft Collins, CO 80523 USA. MIT, Cambridge, MA 02139 USA. Shandong Univ, Jinan 250100, Peoples R China. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Univ Hawaii, Honolulu, HI 96822 USA. Univ Calif Irvine, Irvine, CA 92717 USA. Univ Texas, Richardson, TX 75083 USA. Univ Washington, Seattle, WA 98195 USA. RP Bai, JZ (reprint author), Inst High Energy Phys, Beijing 100039, Peoples R China. RI Chen, Yu/E-3788-2012; OI Li, Xiaonan/0000-0003-2857-0219; Wilson, Robert/0000-0002-8184-4103 NR 31 TC 20 Z9 20 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD JUN 11 PY 1998 VL 429 IS 1-2 BP 188 EP 194 DI 10.1016/S0370-2693(98)00313-X PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ZZ087 UT WOS:000074694400026 ER PT J AU Li, CZ Angelici, RJ AF Li, CZ Angelici, RJ TI A facile synthesis of functionalized catechols SO TETRAHEDRON LETTERS LA English DT Article DE catechol; Michael reactions ID PSEUDOPTEROGORGIA-ELISABETHAE AB A general route to functionalized catechols is achieved by the reaction of 3,6-di(chloromethyl)-4,5-dimethyl-catechol with various nucleophiles in the presence of a base. The reactions are proposed to occur by way of a dehydrochlorinated intermediate which undergoes Michael additions to give the catechol products. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Ames Lab, Ames, IA 50011 USA. RP Angelici, RJ (reprint author), Iowa State Univ, Dept Chem, Ames, IA 50011 USA. NR 13 TC 2 Z9 2 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0040-4039 J9 TETRAHEDRON LETT JI Tetrahedron Lett. PD JUN 11 PY 1998 VL 39 IS 24 BP 4235 EP 4238 DI 10.1016/S0040-4039(98)00793-X PG 4 WC Chemistry, Organic SC Chemistry GA ZR078 UT WOS:000073933500023 ER PT J AU Pomes, R Hummer, G Wikstrom, M AF Pomes, R Hummer, G Wikstrom, M TI Structure and dynamics of a proton shuttle in cytochrome c oxidase SO BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS LA English DT Article; Proceedings Paper CT 10th European Bioenergetics Conference (EBEC) CY JUN 27-JUL 02, 1998 CL GOTHENBURG, SWEDEN DE molecular dynamics; potential of mean force; conformational isomerization; proton translocation; Grotthus mechanism; hydrogen bonding ID WATER CHAIN; GRAMICIDIN; CHANNEL; ENERGY; WIRE AB Protein-assisted transport of protons across the bioenergetic membrane is mediated by hydrogen-bonded networks. These networks involve titratable amino acid residues of membrane-spanning protein assemblies as well as internal water molecules. In cytochrome c oxidase, the so-called D-channel defines such a network for the uptake of protons from the cytoplasmic side of the membrane. It has been proposed that conformational changes of a Glu residue are required for the establishment of a proton linkage from the channel into the active site. The thermodynamic basis for the conformational isomerization of this residue is investigated using simulated annealing and free energy molecular dynamics simulations. The results support the existence of metastable conformations of the side chain, and their interchange through local structural fluctuations of neighboring residues and nearby internal chains of water molecules. The conformational isomerization of both protonated and unprotonated states of Glu, coupled with the reorganization of hydrogen bonds, suggests a kinetically competent mechanism for proton shuttling. (C) 1998 Elsevier Science BN. C1 Los Alamos Natl Lab, Theoret Biol & Biophys Grp, Los Alamos, NM 87545 USA. Univ Helsinki, Helsinki Bioenerget Grp, Dept Med Chem, Inst Biomed Sci, FI-00014 Helsinki, Finland. Univ Helsinki, Biocentrum Helsinki, FI-00014 Helsinki, Finland. RP Los Alamos Natl Lab, Theoret Biol & Biophys Grp, T-10,Mail Stop K-710, Los Alamos, NM 87545 USA. EM regis@lanl.gov RI Wikstrom, Marten/A-4403-2008; Hummer, Gerhard/A-2546-2013 OI Hummer, Gerhard/0000-0001-7768-746X NR 20 TC 72 Z9 72 U1 1 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0005-2728 EI 0006-3002 J9 BBA-BIOENERGETICS JI Biochim. Biophys. Acta-Bioenerg. PD JUN 10 PY 1998 VL 1365 IS 1-2 BP 255 EP 260 DI 10.1016/S0005-2728(98)00077-2 PG 6 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA ZX557 UT WOS:000074530000037 ER PT J AU Murayama, H AF Murayama, H TI Physics at e(-)e(-): A case for multi-channel studies SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (e(minus) e(minus) 97) CY SEP 22-24, 1997 CL UNIV CALIF SANTA CRUZ, SANTA CRUZ, CALIFORNIA SP US DOE, Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ ID COLLIDERS AB I argue that it would be crucial to have as many channels as possible to understand the physics of electroweak symmetry breaking (EWSB) in next-generation collider experiments. A historic example of the parity violation and the V - A interaction is used to make this point. An e(-)e(-) option offers us a new channel in this respect. The usefulness of this channel is exemplified for the case of supersymmetry and of the strongly coupled EWSB sector. C1 Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RP Murayama, H (reprint author), Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RI Murayama, Hitoshi/A-4286-2011 NR 7 TC 2 Z9 2 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD JUN 10 PY 1998 VL 13 IS 14 BP 2227 EP 2234 DI 10.1142/S0217751X98001025 PG 8 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA ZV823 UT WOS:000074344900003 ER PT J AU Czarnecki, A Marciano, WJ AF Czarnecki, A Marciano, WJ TI Parity violating asymmetries at future lepton colliders SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (e(minus) e(minus) 97) CY SEP 22-24, 1997 CL UNIV CALIF SANTA CRUZ, SANTA CRUZ, CALIFORNIA SP US DOE, Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ ID COLLISIONS AB Parity violating left-right scattering asymmetries at future high energy e(+)e(-) and e(-)e(-) colliders are examined. The utility of two polarized beams for precision measurements is pointed out. Sensitivity to "new" short-distance physics is briefly discussed. Electroweak radiative corrections due to the running of sin(2) theta(w) (q(2)) are exhibited. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. RP Czarnecki, A (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. NR 11 TC 16 Z9 16 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD JUN 10 PY 1998 VL 13 IS 14 BP 2235 EP 2244 DI 10.1142/S0217751X98001037 PG 10 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA ZV823 UT WOS:000074344900004 ER PT J AU Rizzo, TG AF Rizzo, TG TI Z ' investigations at future lepton colliders SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (e(minus) e(minus) 97) CY SEP 22-24, 1997 CL UNIV CALIF SANTA CRUZ, SANTA CRUZ, CALIFORNIA SP US DOE, Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ ID MODELS AB In this talk I summarize the capability of future lepton colliders to indirectly discover a new Z' and to determine its couplings to the fermions of the Standard Model. The physics associated with sitting on the Z'-pole is also briefly discussed. This analysis is based on the results presented in the Snowmass 1996 New Gauge Boson Working Group report. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Rizzo, TG (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 14 TC 3 Z9 3 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD JUN 10 PY 1998 VL 13 IS 14 BP 2245 EP 2254 DI 10.1142/S0217751X98001049 PG 10 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA ZV823 UT WOS:000074344900005 ER PT J AU Peskin, ME AF Peskin, ME TI Systematics of slepton production in e(+)e(-) and e(-)e(-) collisions SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (e(minus) e(minus) 97) CY SEP 22-24, 1997 CL UNIV CALIF SANTA CRUZ, SANTA CRUZ, CALIFORNIA SP US DOE, Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ ID STANDARD MODEL; SUPERSYMMETRY; COLLIDERS AB I present the basic formulae for slepton production in e(+)e(-) and e(-)e(-) collisions in an especially simple form, using a helicity basis. This parametrization introduces the useful neutralino functions to connect the neutralino eigenstates to observable cross sections. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Peskin, ME (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 9 TC 12 Z9 12 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD JUN 10 PY 1998 VL 13 IS 14 BP 2299 EP 2305 DI 10.1142/S0217751X98001086 PG 7 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA ZV823 UT WOS:000074344900009 ER PT J AU Feng, JL AF Feng, JL TI Supersymmetry at linear colliders: The importance of being e(-)e(-) SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (e(minus) e(minus) 97) CY SEP 22-24, 1997 CL UNIV CALIF SANTA CRUZ, SANTA CRUZ, CALIFORNIA SP US DOE, Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ ID E(+)E(-) COLLIDERS AB Advantages of the e(-)e(-) option at linear colliders for the study of supersymmetry are ;highlighted. The fermion number violating process e(-)e(-) --> (e) over tilde(-)(e) over tilde(-) provides unique opportunities for studies of slepton masses and flavor mixings. In particular, slepton mass measurements at the 100 MeV level through threshold scans of scalar pair production may be possible. Such measurements are over an order of magnitude better than those possible in e(+)e(-) mode, require far less integrated luminosity, and may lead to precise, model-independent measurements of tan beta. Implications for studying gauginos and the importance of accurate beam polarimetry are also discussed. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RP Feng, JL (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. NR 31 TC 19 Z9 19 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD JUN 10 PY 1998 VL 13 IS 14 BP 2319 EP 2328 DI 10.1142/S0217751X98001104 PG 10 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA ZV823 UT WOS:000074344900011 ER PT J AU Cheng, HC AF Cheng, HC TI Precision supersymmetry measurements at the e(-)e(-) collider SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (e(minus) e(minus) 97) CY SEP 22-24, 1997 CL UNIV CALIF SANTA CRUZ, SANTA CRUZ, CALIFORNIA SP US DOE, Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ ID LINEAR E(+)E(-) COLLIDERS; STANDARD MODEL; BREAKING AB Measurements of supersymmetric particle couplings provide important verification of supersymmetry. If some of the superpartners are at the multi-TeV scale, they will escape direct detection at planned future colliders. However, such particles induce nondecoupling corrections in processes involving the accessible superparticles through violations of the supersymmetric equivalence between gauge boson and gaugino couplings. These violations are analogous to the oblique corrections in the electroweak sector of the Standard Model, and can be parametrized in terms of super-oblique parameters. The e(-)e(-) collision mode of a future linear collider is shown to be an excellent environment for such high precision measurements of these SUSY parameters, which will provide an important probe of superparticles beyond reachable energies. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Cheng, HC (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 24 TC 5 Z9 5 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD JUN 10 PY 1998 VL 13 IS 14 BP 2329 EP 2336 DI 10.1142/S0217751X98001116 PG 8 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA ZV823 UT WOS:000074344900012 ER PT J AU Rizzo, TG AF Rizzo, TG TI Leptoquarks at future lepton colliders SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (e(minus) e(minus) 97) CY SEP 22-24, 1997 CL UNIV CALIF SANTA CRUZ, SANTA CRUZ, CA SP US DOE, Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ ID E-GAMMA COLLISIONS; E+E-COLLIDERS; PHOTON AB In this talk I summarize the capability of future lepton colliders to discover leptoquarks and to determine their electroweak quantum numbers. This analysis is an updated discussion based on the results presented in the Snowmass 1996 New Phenomena Working Group report as well as some more recent work that has appeared in the literature as a result of the HERA high-Q(2) excess. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. EM rizzo@slacvx.slac.stanford.edu NR 42 TC 1 Z9 1 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA 5 TOH TUCK LINK, SINGAPORE 596224, SINGAPORE SN 0217-751X EI 1793-656X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD JUN 10 PY 1998 VL 13 IS 14 BP 2351 EP 2362 DI 10.1142/S0217751X98001141 PG 12 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA ZV823 UT WOS:000074344900015 ER PT J AU Hewett, JL AF Hewett, JL TI Probing top-quark couplings at lepton and photon colliders SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (e(minus) e(minus) 97) CY SEP 22-24, 1997 CL UNIV CALIF SANTA CRUZ, SANTA CRUZ, CALIFORNIA SP US DOE, Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ ID LINEAR COLLIDER; DECAY; B->S-GAMMA AB The ability of high energy lepton and photon colliders to probe the gauge couplings of the top-quark is summarized. 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 30 TC 15 Z9 15 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD JUN 10 PY 1998 VL 13 IS 14 BP 2389 EP 2398 DI 10.1142/S0217751X98001177 PG 10 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA ZV823 UT WOS:000074344900018 ER PT J AU Brodsky, SJ AF Brodsky, SJ TI High energy photon-photon and electron-photon collisions SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (e(minus) e(minus) 97) CY SEP 22-24, 1997 CL UNIV CALIF SANTA CRUZ, SANTA CRUZ, CALIFORNIA SP US DOE, Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ ID MAGNETIC-MOMENT; GAUGE-THEORY; AMPLITUDES; MESON; ZEROS AB The advent of a next linear e(+/-)e(-) collider and back-scattered laser beams will allow the study of a vast array of high energy processes of the Standard Model through the fusion of real and virtual photons and other gauge bosons. As examples, I discuss virtual photon scattering gamma*gamma* --> X in the region dominated by BFKL hard Pomeron exchange and report the predicted cross sections at present and future e(+/-)e(-) colliders. I also discuss exclusive gamma gamma reactions in QCD as a measure of hadron distribution amplitudes and a new method for measuring the anomalous magnetic and quadrupole moments of the W and Z gauge bosons to high precision in polarized electron-photon collisions. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Brodsky, SJ (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 33 TC 1 Z9 1 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD JUN 10 PY 1998 VL 13 IS 14 BP 2417 EP 2427 DI 10.1142/S0217751X98001207 PG 11 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA ZV823 UT WOS:000074344900021 ER PT J AU Panofsky, WKH AF Panofsky, WKH TI Some remarks on the early history of high energy electron-electron scattering SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (e(minus) e(minus) 97) CY SEP 22-24, 1997 CL UNIV CALIF SANTA CRUZ, SANTA CRUZ, CALIFORNIA SP US DOE, Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Panofsky, WKH (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD JUN 10 PY 1998 VL 13 IS 14 BP 2429 EP 2430 DI 10.1142/S0217751X98001219 PG 2 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA ZV823 UT WOS:000074344900022 ER PT J AU Zimmermann, F Thompson, KA Helm, RH AF Zimmermann, F Thompson, KA Helm, RH TI Electron-electron luminosity in the next linear collider - A preliminary study SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (e(minus) e(minus) 97) CY SEP 22-24, 1997 CL UNIV CALIF SANTA CRUZ, SANTA CRUZ, CA SP US DOE, Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ ID PLASMA LENS; DISRUPTION AB In this paper, we discuss some operational aspects of electron-electron collisions at the Next Linear Collider (NLC) and estimate the luminosity attainable in such a machine. We also consider the use of two future technologies which could simplify the operation and improve the luminosity in an e(-)e(-) collider: polarized rf guns and plasma lenses. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Zimmermann, F (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 10 TC 5 Z9 5 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA 5 TOH TUCK LINK, SINGAPORE 596224, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD JUN 10 PY 1998 VL 13 IS 14 BP 2443 EP 2453 DI 10.1142/S0217751X98001232 PG 11 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA ZV823 UT WOS:000074344900024 ER PT J AU Markiewicz, TW Maruyama, T AF Markiewicz, TW Maruyama, T TI Backgrounds at an e(-)e(-) linear collider SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (e(minus) e(minus) 97) CY SEP 22-24, 1997 CL UNIV CALIF SANTA CRUZ, SANTA CRUZ, CALIFORNIA SP US DOE, Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ AB Background sources at a 1 TeV Linear Collider are discussed along with ideas on how to limit their effect on the detector. With modest shielding and an adequate solenoidal field, we find that detector backgrounds are minimal and that the experimental environment should be similar to that which one normally associates with e(+)e(-) colliders. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Markiewicz, TW (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD JUN 10 PY 1998 VL 13 IS 14 BP 2467 EP 2477 DI 10.1142/S0217751X98001256 PG 11 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA ZV823 UT WOS:000074344900026 ER PT J AU Spencer, JE AF Spencer, JE TI Limitations imposed by beam-beam effects and their remedies SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (e(minus) e(minus) 97) CY SEP 22-24, 1997 CL UNIV CALIF SANTA CRUZ, SANTA CRUZ, CALIFORNIA SP US DOE, Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ ID COLLIDER AB Effects that limit the luminosities of a general purpose linear collider or GLC capable of (e) over bar(+/-)(e) over bar(+/-), <(gamma)over bar>(e) over bar and <(gamma)over bar><(gamma)over bar> incident channels are discussed together with potential mitigations. The relative characteristics of such channels and their luminosities are predicted based on differing assumptions - including those for the current configurations for the NLC at root s(cc) = 0.5 and 1.0 TeV. Disadvantages related to the increased complexity of linear colliders can be offset by broader design constraints that seek to optimize the generalized luminosity. Decreased disruptions and bunch charges are effective and can be used in combination with feasable charge compensation schemes to predict higher luminosities and power conversion efficiencies. The incremental costs of additional channels is modest compared to the cost of any one by itself or potential gains in the integrated luminosity. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Spencer, JE (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 20 TC 6 Z9 6 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD JUN 10 PY 1998 VL 13 IS 14 BP 2479 EP 2492 DI 10.1142/S0217751X98001268 PG 14 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA ZV823 UT WOS:000074344900027 ER PT J AU Erickson, R AF Erickson, R TI e(-)e(-) collisions in a TeV linear collider built for e(+)e(-) operation SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (e(minus) e(minus) 97) CY SEP 22-24, 1997 CL UNIV CALIF SANTA CRUZ, SANTA CRUZ, CALIFORNIA SP US DOE, Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ AB In this paper, we discuss practical issues that must be addressed to reconfigure an e(+)e(-) linear collider for e(-)e(-) operation and argue that modest steps should be taken during the design stage to preserve this option. C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Erickson, R (reprint author), Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 3 TC 2 Z9 2 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD JUN 10 PY 1998 VL 13 IS 14 BP 2493 EP 2499 DI 10.1142/S0217751X9800127X PG 7 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA ZV823 UT WOS:000074344900028 ER PT J AU Weidemann, AW AF Weidemann, AW TI Cain simulation studies for e(-)e(-) collisions SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (e(minus) e(minus) 97) CY SEP 22-24, 1997 CL UNIV CALIF SANTA CRUZ, SANTA CRUZ, CALIFORNIA SP US DOE, Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ AB Disruption effects in e(-)e(-) collisions at a future linear collider affect the attainable luminosity; the angular spread of the disrupted beam particles may present a background in a detector. In this paper, I present simulations of the beam-beam interaction with the simulation code CAIN of relevance for these questions. C1 Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. RP Weidemann, AW (reprint author), Stanford Linear Accelerator Ctr, MS 94,POB 4349, Stanford, CA 94309 USA. NR 3 TC 1 Z9 1 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD JUN 10 PY 1998 VL 13 IS 14 BP 2501 EP 2506 DI 10.1142/S0217751X98001281 PG 6 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA ZV823 UT WOS:000074344900029 ER PT J AU Clendenin, JE AF Clendenin, JE TI Highly polarized electron beams for linear colliders SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (e(minus) e(minus) 97) CY SEP 22-24, 1997 CL UNIV CALIF SANTA CRUZ, SANTA CRUZ, CALIFORNIA SP US DOE, Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ ID GALLIUM-ARSENIDE; ENERGY-ANALYSIS; SPIN AB The SLC operates with electron beams having a polarization of similar to 80%. The physics opportunities for future colliders will be greatly enhanced if the beam polarization can be significantly higher. The prospects for achieving electron single-beam polarizations > 95% are discussed. A complimentary achievement would be to use two-beam polarization. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Clendenin, JE (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 20 TC 6 Z9 6 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD JUN 10 PY 1998 VL 13 IS 14 BP 2507 EP 2516 DI 10.1142/S0217751X98001293 PG 10 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA ZV823 UT WOS:000074344900030 ER PT J AU Woods, M AF Woods, M TI Compton polarimetry at a 1 TeV linear collider SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (e(minus) e(minus) 97) CY SEP 22-24, 1997 CL UNIV CALIF SANTA CRUZ, SANTA CRUZ, CALIFORNIA SP US DOE, Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ AB An electron beam polarization of 80% or greater will be a key feature of a 1 TeV Linear Collider. Accurate measurements of the beam polarization will therefore be needed. We discuss design considerations and capabilities for a Compton-scattering polarimeter located in the extraction line from the Interaction Point. Polarization measurements with 1% accuracy taken parasitic to collision data look feasible, but detailed simulations are needed. Polarimeter design issues are similar for both electron-positron and electron-electron collider modes, though beam disruption creates more difficulties for the electron-electron mode. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Woods, M (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 12 TC 4 Z9 4 U1 0 U2 1 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD JUN 10 PY 1998 VL 13 IS 14 BP 2517 EP 2524 DI 10.1142/S0217751X9800130X PG 8 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA ZV823 UT WOS:000074344900031 ER PT J AU Zimmermann, F Whittum, DH AF Zimmermann, F Whittum, DH TI Final-focus system and collision schemes for a 5-TeV W-band linear collider SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (e(minus) e(minus) 97) CY SEP 22-24, 1997 CL UNIV CALIF SANTA CRUZ, SANTA CRUZ, CALIFORNIA SP US DOE, Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ ID LUMINOSITY AB A 3-km long high-gradient W-band switched matrix linac may, in parallel channels, accelerate multiple electron and positron bunches to an energy of 2.5 TeV, with a tight control on the intra-bunch energy spread. In this report, we describe a final-focus system for such an accelerator, whose length is restrained by eliminating chromatic correction. The interaction point (IP) spot size is limited by synchrotron radiation in the last quadrupole (Oide effect). The energy loss due to beamstrahlung is optionally suppressed by combining bunches of opposite charge and colliding the neutral beams. We present two different high-luminosity multiple-collision schemes, which can provide a luminosity of up to 10(35) cm(-2) s(-1) with only about 1 MW average beam power. In the first scheme, batches of equally-charged bunches are combined into superbunches which, possibly after charge compensation, are collided head-on with the opposing beam. In the second scheme, 25 charge-neutral electron-positron bunch pairs of one beam are each collided with 25 neutral bunch pairs of the other beam. These multiplexed collisions are facilitated by a crossing angle and by crab cavities upstream of the electron-positron combiner; however they also require focusing channels (e.g., a crystal) preserving the IP beam size between the collision points, a difficult if not impossible construct. We describe the challenges posed by each approach. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Zimmermann, F (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 20 TC 4 Z9 4 U1 0 U2 1 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD JUN 10 PY 1998 VL 13 IS 14 BP 2525 EP 2549 DI 10.1142/S0217751X98001311 PG 25 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA ZV823 UT WOS:000074344900032 ER PT J AU Gor'kov, LP Kresin, VZ AF Gor'kov, LP Kresin, VZ TI Manganites at low temperatures and light doping: band approach and percolation SO JETP LETTERS LA English DT Article ID LA1-XSRXMNO3 AB A tight-band model is employed for the e(2g) orbitals in manganites. It is shown that a large intra-atomic Hund coupling J(H) and the resulting double-exchange mechanism lead to antiferromagnetic ordering along one of the cubic axes, stabilized by the cooperative Jahn-Teller effect, which further decreases the band energy of the electrons. As a result, LaMnO3 is a band insulator built of 2D ferromagnetic layers. The critical concentration (x(c) similar or equal to 0.16) for the onset of ferromagnetic and metallic behavior at low temperatures in La1-xSrxMnO3 and the phase transition are treated in a percolation approach. (C) 1998 American Institute of Physics. [S0021-3640(98)01811-8]. C1 Florida State Univ, Natl High Magnet Field Lab, Tallahassee, FL 32310 USA. LD Landau Theoret Phys Inst, Moscow 117334, Russia. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Gor'kov, LP (reprint author), Florida State Univ, Natl High Magnet Field Lab, Tallahassee, FL 32310 USA. NR 17 TC 84 Z9 84 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-3640 J9 JETP LETT+ JI Jetp Lett. PD JUN 10 PY 1998 VL 67 IS 11 BP 985 EP 990 DI 10.1134/1.567783 PG 6 WC Physics, Multidisciplinary SC Physics GA 108GV UT WOS:000075258600018 ER PT J AU Ribeiro, FH Gerken, CA Rupprechter, G Somorjai, GA Kellner, CS Coulston, GW Manzer, LE Abrams, L AF Ribeiro, FH Gerken, CA Rupprechter, G Somorjai, GA Kellner, CS Coulston, GW Manzer, LE Abrams, L TI Structure insensitivity and effect of sulfur in the reaction of hydrodechlorination of 1,1-dichlorotetrafluoroethane (CF3-CFCl2) over Pd catalysts SO JOURNAL OF CATALYSIS LA English DT Article ID PD(111) SURFACE; CARBON-MONOXIDE; ADSORPTION; HYDROGEN; LEED AB The kinetics of the hydrodechlorination of 1,1-dichlorotetrafluoroethane (CFC 114a) was studied on Pd(III), Pd(100), and a Pd foil at atmospheric pressure, The three products formed were CF3-CFH2 (HFC 134a), CF3-CFClH (HCFC 124), and CF3-CH3 (HFC 143a) with selectivities independent of conversion. The single crystals and foil (model catalysts) were studied in an apparatus that permitted the direct transfer of samples between a high pressure cell (1 atm) and an ultrahigh vacuum chamber, The reaction rates were measured in the temperature range of 350 to 470 K, The reaction is not sensitive to the structure of the catalyst, as indicated by the similar turnover rates for all catalysts tested. The reaction is inverse first order in the reaction product HCl on all samples. Sulfur adsorbed on the Pd surface depressed the rates of formation of 134a more strongly than the rates of 124 and 143a. (C) 1998 Academic Press. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Dupont Co, Cent Res & Dev, Expt Stn, Corp Catalysis Ctr, Wilmington, DE 19880 USA. RP Ribeiro, FH (reprint author), Worcester Polytech Inst, Dept Chem Engn, Worcester, MA 01609 USA. OI Ribeiro, Fabio/0000-0001-7752-461X NR 16 TC 57 Z9 58 U1 1 U2 3 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9517 J9 J CATAL JI J. Catal. PD JUN 10 PY 1998 VL 176 IS 2 BP 352 EP 357 DI 10.1006/jcat.1998.2059 PG 6 WC Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA ZV169 UT WOS:000074276900009 ER PT J AU Goldstein, S Saha, A Lymar, SV Czapski, G AF Goldstein, S Saha, A Lymar, SV Czapski, G TI Oxidation of peroxynitrite by inorganic radicals: A pulse radiolysis study SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID AQUEOUS-SOLUTION; HYDROXYL RADICALS; CARBON-DIOXIDE; RATE CONSTANTS; WATER; N2O4; NO AB Reactivity of the peroxynitrite ion toward a number of inorganic radicals was determined by using the pulse radiolysis technique. The rate constants for the oxidation of the ONOO- ion by CO3.-, N-.(3), and ClO2. radicals were determined from their decay kinetics to be (7.7 +/- 1.2) x 10(6) (I = 0.6 M), (7.2 +/- 0.9) x 10(8), and (3.2 +/- 0.3) x 10(4) M-1 s(-1), respectively. For the (OH)-O-. radical, the rate constant of (4.8 +/- 0.8) x 10(9) M-1 s(-1) was obtained by using competition kinetic analysis. The oxidation potential of the ONOO- ion was estimated as 0.8 V from the kinetic data. Although thermodynamically favorable, oxidation of ONOO- by the (NO2)-N-. radical was not observed; an upper limit of 2.5 x 10(4 )M(-1) s(-1) could be set for this reaction. Contribution from some of these reactions to the decomposition of peroxynitrite in the presence and absence of CO2 is discussed. C1 Hebrew Univ Jerusalem, Dept Phys Chem, IL-91904 Jerusalem, Israel. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Goldstein, S (reprint author), Hebrew Univ Jerusalem, Dept Phys Chem, IL-91904 Jerusalem, Israel. NR 31 TC 42 Z9 42 U1 0 U2 2 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 JUN 10 PY 1998 VL 120 IS 22 BP 5549 EP 5554 DI 10.1021/ja9735362 PG 6 WC Chemistry, Multidisciplinary SC Chemistry GA ZU595 UT WOS:000074213800022 ER PT J AU Salsbury, FR Harris, RA AF Salsbury, FR Harris, RA TI Estimation of the Fermi contact contribution to the xenon-hydrogen and xenon-xenon spin-spin coupling constants SO MOLECULAR PHYSICS LA English DT Article ID DENSITY-FUNCTIONAL THEORY AB The Fermi contact interaction contribution to the spin-spin coupling constant is calculated for Xe-H and Xe-129-Xe-131. The method used is a simple density functional theory of responses. In the regions of interest, J(Xe-H) is microHz, and J(Xe-129-Xe-131) is milliHz. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Salsbury, FR (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Salsbury, Freddie/A-5923-2008 NR 17 TC 20 Z9 20 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0026-8976 J9 MOL PHYS JI Mol. Phys. PD JUN 10 PY 1998 VL 94 IS 2 BP 307 EP 312 DI 10.1080/002689798168187 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZR704 UT WOS:000074005400009 ER PT J AU Cha, YS Askew, TR AF Cha, YS Askew, TR TI Transient response of a high-temperature superconductor tube to pulsed magnetic fields SO PHYSICA C LA English DT Article DE superconductor tube; pulsed magnetic fields; excitation current ID FAULT CURRENT LIMITER AB The transient response of a melt-cast-processed BSCCO-2212 superconductor mbe under a pulsed magnetic field was investigated by using a pulsed current source driving an external copper solenoid. The induced current in the superconductor tube was measured by a Rogowski coil and the penetration field was measured by a Hall probe inside the tube. It was found that (a) the maximum induced current I-s(max) and the excitation current at field penetration NI* increase with the maximum excitation current NI(max); (b) there is a time delay between peak NI and peak H in tests with relatively low NI(max), and this time delay diminishes in tests with relatively large NI(max); (c) the induced current I-s does not remain constant and begins to decrease immediately after its peak has been reached while the excitation current NI is still increasing; and (d) the decay of the induced current I-s exhibited different behavior between tests with relatively low and high NI(max), the former showed a gradual decay while the latter showed a rapid decay initially and then a nearly constant value for an extended period of time. All of these observations can be explained by magnetic diffusion and a postulated transition from flux-creep to flux-flow behavior. The constant value of induced current after its rapid decay can be interpreted as the steady-state critical current of the superconductor tube. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. Kalamazoo Coll, Dept Phys, Kalamazoo, MI 49006 USA. RP Cha, YS (reprint author), Argonne Natl Lab, Div Energy Technol, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 15 TC 18 Z9 18 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 JUN 10 PY 1998 VL 302 IS 1 BP 57 EP 66 DI 10.1016/S0921-4534(98)00191-9 PG 10 WC Physics, Applied SC Physics GA ZW854 UT WOS:000074455000007 ER PT J AU List, FA Goyal, A Paranthaman, M Norton, DP Specht, ED Lee, DF Kroeger, DM AF List, FA Goyal, A Paranthaman, M Norton, DP Specht, ED Lee, DF Kroeger, DM TI High J(c) YBCO films on biaxially textured Ni with oxide buffer layers deposited using electron beam evaporation and sputtering SO PHYSICA C LA English DT Article DE YBCO; thin films; applications of high-T-c superconductors; epitaxy ID CRITICAL-CURRENT DENSITY; SUPERCONDUCTING TAPES AB Epitaxial buffer layers of CeO2 and yttria-stabilized ZrO2 (YSZ) have been deposited on biaxially textured nickel using conventional electron beam evaporation and r-f sputtering. Epitaxial films of YBa2Cu3O7-delta (YBCO) have been then grown on these buffered substrates using pulsed laser deposition (PLD). Despite intermittent exposure of the buffered substrates to 1 atm air, the resulting YBCO conductors exhibited transport critical current densities (J(c)) of 0.8 MA/cm(2) at 77.3 K and H = 0 T. The dependence of J(c) of these conductors on temperature and magnetic field is similar to that of conductors prepared solely by in situ PLD. These results suggest that it may be possible to use more flexible and easily scalable fabrication methods for preparing long YBCO conductors. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP List, FA (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. RI Specht, Eliot/A-5654-2009; Paranthaman, Mariappan/N-3866-2015 OI Specht, Eliot/0000-0002-3191-2163; Paranthaman, Mariappan/0000-0003-3009-8531 NR 8 TC 62 Z9 63 U1 0 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD JUN 10 PY 1998 VL 302 IS 1 BP 87 EP 92 DI 10.1016/S0921-4534(98)00154-3 PG 6 WC Physics, Applied SC Physics GA ZW854 UT WOS:000074455000010 ER PT J AU Jagoe, CH Arnold-Hill, B Yanochko, GM Winger, PV Brisbin, IL AF Jagoe, CH Arnold-Hill, B Yanochko, GM Winger, PV Brisbin, IL TI Mercury in alligators (Alligator mississippiensis) in the southeastern United States SO SCIENCE OF THE TOTAL ENVIRONMENT LA English DT Article DE tissue mercury; bioaccumulation; alligator; crocodilian; reptile ID METHYL MERCURY; NORTHERN MANITOBA; LAKES; ECOSYSTEMS; SEDIMENTS; FISH AB Mercury methylation may be enhanced in wetlands and humic-rich, blackwater systems that crocodiles and alligators typically inhabit. Given their high trophic level and long life-spans, crocodilians could accumulate significant burdens of Hg. Our objectives were to survey Hg concentrations in alligators from several areas in the southeastern United States to test their utility as sentinels of Hg contamination, to examine relationships among Hg concentrations in various tissues and to Look for any differences in tissue Hg concentrations among locations. We measured total Hg concentrations in alligators collected in the Florida Everglades (n = 18), the Okefenokee National Wildlife Refuge, Georgia (n = 9), the Savannah River Site (SRS), South Carolina (n = 49) and various locations in central Florida (n = 21), sampling tissues including blood, brain, liver, kidney, muscle, bone, fat, spleen, claws and dermal scutes. Alligators from the Everglades were mostly juvenile, but Hg concentrations in tissues were high (means: liver 41.0, kidney 36.4, muscle 5.6 mg Hg/kg dry wt.). Concentrations in alligators from other locations in Florida were lower (means: liver 14.6, kidney 12.6, muscle 1.8 mg Hg/kg dry wt.), although they tended to be larger adults. Alligators from the Okefenokee were smallest and had the lowest Hg concentrations (means: liver 4.3, kidney 4.8, muscle 0.8 mg Hg/kg dry wt.). SRS alligators had the greatest size range and intermediate Hg levels (means: liver 14.9, muscle 4.8 mg Hg/kg dry wt.). At some locations, alligator length was correlated with Hg concentrations in some internal organs. However, at three of the four locations, muscle Hg was not related to length. Tissue Hg concentrations were correlated at most locations however, claw or dermal scute Hg explained less than 74% of the variation of Hg in muscle or organs, suggesting readily-obtained tissues, such as scutes or claws, have limited value for non-destructive screening of Hg in alligator populations. (C) 1998 Published by Elsevier Science B.V. C1 Univ Georgia, Savannah River Ecol Lab, Aiken, SC 29802 USA. Univ Georgia, Inst Ecol, Athens, GA 30602 USA. Univ Georgia, DB Warnell Sch Forest Resources, Patuxent Wildlife Res Ctr, US Natl Biol Serv, Athens, GA 30602 USA. RP Jagoe, CH (reprint author), Univ Georgia, Savannah River Ecol Lab, PO Drawer E, Aiken, SC 29802 USA. EM jagoe@srel.edu NR 17 TC 34 Z9 37 U1 1 U2 22 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 JUN 10 PY 1998 VL 213 IS 1-3 BP 255 EP 262 DI 10.1016/S0048-9697(98)00098-9 PG 8 WC Environmental Sciences SC Environmental Sciences & Ecology GA ZU102 UT WOS:000074162000028 PM 9652131 ER PT J AU Watson, GM Gibbs, D Zehner, DM Yoon, M Mochrie, SGJ AF Watson, GM Gibbs, D Zehner, DM Yoon, M Mochrie, SGJ TI Orientational phase diagram of the stepped Au(001) surface SO SURFACE SCIENCE LA English DT Article DE equilibrium thermodynamics and statistical mechanics; gold; single crystal surfaces; stepped single crystal surfaces; X-ray scattering, diffraction, and reflection ID HEXAGONALLY RECONSTRUCTED PT(001); GOLD SURFACES; EPITAXY; CRYSTALS; AU(100) AB We report an X-ray scattering study of the structure and morphology of a stepped Au(001) surface between room temperature and bulk melting. At high temperatures, between 1170 and 1220 K, the vicinal Au(001) surface appears rough. Below T-0 = 1170 K, there is a facetting transition: hexagonally reconstructed (001) facets appear in coexistence with unreconstructed, stepped domains. The tilt angle of the stepped domains increases with decreasing temperature, exhibiting a power-law behavior versus reduced temperature. The phase behavior of the hexagonally reconstructed domains follows that observed on nominally unstepped Au(001) surfaces. At T-1 = 992 K, there is a second facetting transition at which the stepped domains reconstruct to form a rotated and corrugated, quasi-hexagonal structure. The corrugation is threefold commensurate with the average terrace width, consistent with a 2 degrees magic vicinal phase. The orientational phase diagram of vicinal Au(001) is deduced and found to be qualitatively similar to that of vicinal Pt(001), although with intriguing differences. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Maryland Baltimore Cty, Dept Phys, Baltimore, MD 21250 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. RP Watson, GM (reprint author), Univ Maryland Baltimore Cty, Dept Phys, 1000 Hilltop Circle, Baltimore, MD 21250 USA. NR 31 TC 11 Z9 11 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JUN 10 PY 1998 VL 407 IS 1-3 BP 59 EP 72 DI 10.1016/S0039-6028(98)00112-5 PG 14 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA ZX834 UT WOS:000074560100018 ER PT J AU Tammaro, M Evans, JW Rastomjee, CS Swiech, W Bradshaw, AM Imbihl, R AF Tammaro, M Evans, JW Rastomjee, CS Swiech, W Bradshaw, AM Imbihl, R TI Reaction-diffusion front propagation across stepped surfaces during catalytic oxidation of CO on Pt(100) SO SURFACE SCIENCE LA English DT Article DE CO-oxidation; Pt(100); reaction-diffusion fronts; steps; surface diffusion ID ELECTRON-MICROSCOPY AB High-resolution microscopy studies of the removal of CO-adlayers on Pt(100) by exposure to oxygen reveal that reaction-diffusion front propagation is impeded both by mesoscopic step bunches and by monoatomic steps. The resulting "stop-and-go" nature to front propagation can be characterized in terms of a time delay for crossing each step bunch or step, at least when the separation of these defects is comparable to or exceeds the width of the front. Here, eve quantify this time delay in terms of the reduced diffusion coefficient for CO in step bunch regions and the width of these regions, or in terms of the reduced hop rate for CO across monoatomic steps. We also briefly examine front propagation across arrays of more closely spaced steps. Results facilitate assessment of terrace diffusivities from average or macroscopic front propagation velocities across multiply stepped surfaces. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys, Ames, IA 50011 USA. Iowa State Univ, Dept Math, Ames, IA 50011 USA. Max Planck Gesell, Fritz Haber Inst, D-14195 Berlin, Germany. Univ Hannover, Inst Phys Chem & Elektrochem, D-30167 Hannover, Germany. RP Evans, JW (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. EM evans@ameslab.gov NR 19 TC 15 Z9 15 U1 2 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JUN 10 PY 1998 VL 407 IS 1-3 BP 162 EP 170 DI 10.1016/S0039-6028(98)00168-X PG 9 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA ZX834 UT WOS:000074560100028 ER PT J AU Rodriguez, JA Jirsak, T Chaturvedi, S Hrbek, J AF Rodriguez, JA Jirsak, T Chaturvedi, S Hrbek, J TI The interaction of H2S and S-2 with Cs and Cs/ZnO surfaces: photoemission and molecular-orbital studies SO SURFACE SCIENCE LA English DT Article DE ab initio quantum-chemical calculations; alkali metals; cesium; hydrogen sulphide; photoelectron spectroscopy; sulfur; surface chemical reaction; zinc oxide ID METAL-SURFACES; PROMOTED SULFIDATION; HYDROGEN-SULFIDE; CO CHEMISORPTION; OXIDE SURFACES; ZINC-OXIDE; ADSORPTION; SULFUR; MODEL; ZNO AB The surface chemistry of H2S and S-2 on metallic Cs and Cs/ZnO surfaces has been investigated using high-resolution synchrotron based photoemission and ab initio self-consistent-field calculations. Metallic Cs is very reactive toward H2S and S-2 at temperatures between 100 and 300 K. Pure cesium decomposes H2S to form Cs2S compounds. After dosing S-2 to Cs, one obtains Cs2S and Cs2S2m (m greater than or equal to 1) compounds. The formation of cesium sulfides induces an increase in the intensity of the Cs 3d levels and large negative shifts (0.8-1.3 eV) in their peak positions. Cesium atoms supported on ZnO are in an ionic state (Csdelta+), but they are still able to interact with H2S and S-2 more strongly than Zn and O sites of the oxide support. A correlation is found between the electron density on the Cs adatoms and their reactivity: Cs atoms supported on Zn sites of the oxide bond S-containing species (H2S, HS, S-2, S) are stronger than Cs atoms supported on O sites. H2S dissociates into HS and atomic S upon adsorption on Cs/ZnO surfaces at 300 K. The HS species decompose at temperatures below 450 K leaving S atoms that are bonded to Cs and Zn. The adsorption of S-2 on Cs/ZnO surfaces at 300 K leads to the formation of Cs2S and Cs2S2m (m greater than or equal to 1) compounds. Cs<->S interactions increase the thermal stability of cesium on the ZnO surface. The poisoning of Cs/Cu/ZnO catalysts is discussed in light of these results and those previously reported for the S-2/Cu/ZnO system. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Rodriguez, JA (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. EM rodrigez@quantum.chm.bnl.gov RI Hrbek, Jan/I-1020-2013 NR 77 TC 34 Z9 38 U1 0 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 JUN 10 PY 1998 VL 407 IS 1-3 BP 171 EP 188 DI 10.1016/S0039-6028(98)00169-1 PG 18 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA ZX834 UT WOS:000074560100029 ER PT J AU Xu, L Bluhm, H Salmeron, M AF Xu, L Bluhm, H Salmeron, M TI An AFM study of the tribological properties of NaCl (100) surfaces under moist air SO SURFACE SCIENCE LA English DT Article DE adhesion; alkali halides; atomic force microscopy; friction; tribology; solid-liquid interfaces; water ID FRICTION AB Water molecules in the air play a very important role in the modification of the physical and chemical properties of NaCl surfaces. In this paper, we report on the dependence of the friction force between this alkali halide and a Pt-coated tip on the external load at different humidity levels. The results clearly demonstrate that the tribological properties of the surface are modified by water adsorption. We also found that at high humidity and below a certain threshold load, the water layer can act as a lubricant. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Shanghai Inst Nucl Res, Shanghai 210800, Peoples R China. RP Salmeron, M (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. EM salmeron@stm.lbl.gov NR 11 TC 36 Z9 37 U1 2 U2 13 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JUN 10 PY 1998 VL 407 IS 1-3 BP 251 EP 255 DI 10.1016/S0039-6028(98)00199-X PG 5 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA ZX834 UT WOS:000074560100035 ER PT J AU Utschig, LM Ohigashi, Y Thurnauer, MC Tiede, DM AF Utschig, LM Ohigashi, Y Thurnauer, MC Tiede, DM TI A new metal-binding site in photosynthetic bacterial reaction centers that modulates Q(A) to Q(B) electron transfer SO BIOCHEMISTRY LA English DT Article ID RHODOBACTER-SPHAEROIDES R-26; REACTION CENTER PROTEIN; RHODOPSEUDOMONAS-SPHAEROIDES; FREE-ENERGY; KINETICS; TEMPERATURE; SPHEROIDES; QUINONES; ACCEPTOR; FE-2+ AB Isolated reaction centers (RCs) from Rhodobacter sphaeroides were found to bind Zn(II) stoichiometrically and reversibly in addition to the 1 equiv of non-heme Fe(II). Metal and EPR analyses confirm that Zn(II) is ligated to a binding site that is distinct from the Fe site. When Zn(II) is bound to this site, electron transfer between the quinones Q(A) and Q(B) (Q(A)(-)Q(B) --> Q(A)Q(B)(-)) is slowed and the room-temperature kinetics become distributed across the microsecond to millisecond time domain. This effect of metal binding on the kinetics is similar to the more global effect of cooling RCs to 2 degrees C in the absence of Zn(II). This suggests that Zn(II) binding alters localized protein motions that are necessary for rapid Q(A)(-)Q(B) --> Q(A)Q(B)(-) electron transfer. Inspection of the RC crystal structure suggests a cluster of histidine Ligands located beneath the QB binding pocket as a potential binding site. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Utschig, LM (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. EM utschig@anlchm.chm.anl.gov NR 30 TC 62 Z9 63 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD JUN 9 PY 1998 VL 37 IS 23 BP 8278 EP 8281 DI 10.1021/bi980395n PG 4 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA ZU195 UT WOS:000074171800002 PM 9622479 ER PT J AU Zaban, A Micic, OI Gregg, BA Nozik, AJ AF Zaban, A Micic, OI Gregg, BA Nozik, AJ TI Photosensitization of nanoporous TiO2 electrodes with InP quantum dots SO LANGMUIR LA English DT Article ID SOLAR CONVERSION EFFICIENCY; SEMICONDUCTOR; JUNCTION; SURFACE; SENSITIZATION; PARTICLES; FILMS; LIGHT; CELL; PBS AB Quantum dots (QDs) of InP strongly adsorb onto transparent, porous, nanocrystalline TiO2 electrodes prepared by sintering 200-250 Angstrom diameter TiO2 colloidal particles. The interparticle space of the TiO2 electrodes is large enough to permit deep penetration of 65-Angstrom InP QDs into the porous TiO2 film. The absorption of light increases linearly with the thickness of the TiO2 film indicating that the InP QDs are adsorbed homogeneously on the TiO2 surface. We found that large particles adsorb better than smaller ones probably due to less hindrance by the stabilizer. The solid films exhibit strong photoconductivity in the visible region indicating photosensitization of TiO2 by InP QDs. The photocurrent action spectrum of the TiO2/InP QD film at a potential of +1 V is consistent with the absorption spectrum of the InP QDs. A photoelectrochemical cell was formed that consisted of p-type InP QDs loaded on TiO2, which was immersed in a I-/I-3(-) or hydroquinone/quinone acetonitrile solution, and a Pt counter electrode. These photoelectrochemical experiments show that electron transfer from InP QD into TiO2 nanoparticles occurs. p-Type InP/TiO2 electrodes are stable during illumination while n-type photocorrodes in an electrochemical cell. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Micic, OI (reprint author), Natl Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80401 USA. RI Nozik, Arthur/A-1481-2012; Nozik, Arthur/P-2641-2016 NR 22 TC 410 Z9 421 U1 6 U2 151 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD JUN 9 PY 1998 VL 14 IS 12 BP 3153 EP 3156 DI 10.1021/la9713863 PG 4 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA ZU371 UT WOS:000074190400003 ER PT J AU Kamata, K Kawamoto, H Honma, T Iwama, T Kim, SH AF Kamata, K Kawamoto, H Honma, T Iwama, T Kim, SH TI Structural basis for chemical inhibition of human blood coagulation factor Xa SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID HUMAN ALPHA-THROMBIN; CELL PROTEASE RECEPTOR-1; RAY CRYSTAL-STRUCTURE; ACTIVE-SITE; TISSUE FACTOR; DRUG DESIGN; RESOLUTION; COMPLEX; BINDING; DOMAIN AB Factor Xa, the converting enzyme of prothrombin to thrombin, has emerged as an alternative (to thrombin) target for drug discovery for thromboembolic diseases. An inhibitor has been synthesized and the crystal structure of the complex between Des [1-44] factor Xa and the inhibitor has been determined by crystallographic methods in two different crystal forms to 2.3- and 2.4-Angstrom resolution. The racemic mixture-of inhibitor FX-2212, (2RS)-(3'-amidino-3-biphenylyl)-5-(4-pyridylamino)pentanoic acid, inhibits-factor Xa activity by 50% at 272 nM in vitro. The S-isomer of FX-2212 (FX-2212a) was found to bind to the active site of factor Xa in both Crystal forms. The biphenylamidine of FX-2212a occupies the S1-pocket, and the pyridine ring makes hydrophobic interactions with the factor Xa aryl-binding site. Several water molecules meditate inhibitor binding to residues in the active site. In contrast to the earlier crystal structures of factor Xa, such as those of apo-Des[1-45] factor Xa and Des[1-44] factor Xa in complex with a naphthyl inhibitor DX-9065a, two epidermal growth factor-like domains of factor Xa are well ordered in both our crystal forms as well as the region between the two domains, which recently was found to be the binding site of the effector cell protease receptor-1. This structure provides a basis for designing next generation inhibitors of factor Xa. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Banyu Pharmaceut Co Ltd, Tsukuba Res Inst, Tsukuba, Ibaraki 30033, Japan. RP Kim, SH (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 47 TC 106 Z9 109 U1 0 U2 1 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD JUN 9 PY 1998 VL 95 IS 12 BP 6630 EP 6635 DI 10.1073/pnas.95.12.6630 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZT829 UT WOS:000074131900013 PM 9618463 ER PT J AU Hahn, DW AF Hahn, DW TI Laser-induced breakdown spectroscopy for sizing and elemental analysis of discrete aerosol particles SO APPLIED PHYSICS LETTERS LA English DT Article AB The laser-induced breakdown spectroscopy technique has been extended to provide quantitative analysis of the mass and elemental composition of individual, submicrometer to micrometer-sized aerosol particles. A two-part approach was used for calibration of the overall mass concentration response, and of the characteristic plasma volume, equal to 2.5 x 10(-4) cm(3). Laboratory results are presented for submicrometer-sized particles containing a known concentration of magnetite. Additional data are presented for fine particulate matter measured in ambient air, including: magnesium-containing particles with an average size of 313 nm. (C) 1998 American Institute of Physics. C1 Sandia Natl Labs, Livermore, CA 94551 USA. RP Hahn, DW (reprint author), Sandia Natl Labs, Livermore, CA 94551 USA. NR 11 TC 65 Z9 71 U1 1 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 8 PY 1998 VL 72 IS 23 BP 2960 EP 2962 DI 10.1063/1.121507 PG 3 WC Physics, Applied SC Physics GA 108PD UT WOS:000075273900012 ER PT J AU Munkholm, A Thompson, C Foster, CM Eastman, JA Auciello, O Stephenson, GB Fini, P DenBaars, SP Speck, JS AF Munkholm, A Thompson, C Foster, CM Eastman, JA Auciello, O Stephenson, GB Fini, P DenBaars, SP Speck, JS TI Determination of the cubic to hexagonal fraction in GaN nucleation layers using grazing incidence x-ray scattering SO APPLIED PHYSICS LETTERS LA English DT Article ID CHEMICAL-VAPOR-DEPOSITION; GROWN GAN; EVOLUTION; SAPPHIRE; FILMS AB Recent electron diffraction and microscopy studies of GaN nucleation layers have shown that, faults in the stacking of the close-packed planes result in the coexistence of cubic and hexagonal phases within the layers. Using grazing incidence x-ray scattering, we have quantified the proportion of the cubic and hexagonal phases throughout the nucleation layer. We compare the structure of a 20 nm nucleation layer grown on sapphire by atmospheric pressure metal-organic chemical vapor deposition at 525 degrees C to that of an identical layer heated to 1060 degrees C. The fractions of cubic and hexagonal phases in the layers are determined by a comparison of the scattering data with a Hendricks-Teller model. High temperature exposure results in a decrease of the cubic fraction from 0.56 to 0.17. The good agreement with. the Hendricks-Teller model indicates that the positions of the stacking faults are uncorrelated, (C) 1998 American Institute of Physics. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Univ Calif Santa Barbara, Dept Mat, Santa Barbara, CA 93106 USA. RP Munkholm, A (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Eastman, Jeffrey/E-4380-2011; Speck, James/H-5646-2011; OI Eastman, Jeff/0000-0002-0847-4265; Thompson, Carol/0000-0003-3832-4855 NR 18 TC 35 Z9 36 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 8 PY 1998 VL 72 IS 23 BP 2972 EP 2974 DI 10.1063/1.121511 PG 3 WC Physics, Applied SC Physics GA 108PD UT WOS:000075273900016 ER PT J AU Geohegan, DB Puretzky, AA Duscher, G Pennycook, SJ AF Geohegan, DB Puretzky, AA Duscher, G Pennycook, SJ TI Time-resolved imaging of gas phase nanoparticle synthesis by laser ablation SO APPLIED PHYSICS LETTERS LA English DT Article ID SILICON NANOCRYSTALLITES; PHOTOLUMINESCENCE; EMISSION; CLUSTERS AB The dynamics of nanoparticle formation, transport, and deposition by pulsed laser ablation of c-Si into 1-10 Torr He and Ar gases are revealed by imaging laser-induced photoluminescence and Rayleigh-scattered light from gas-suspended 1-10 nm SiOx particles. Two sets of dynamic phenomena are presented for times up to 15 s after KrF-laser ablation. Ablation of Si into heavier Ar results in a uniform, stationary plume of nanoparticles, while Si ablation into lighter He results in a turbulent ring of particles which propagates forward at 10 m/s. Nanoparticles unambiguously formed in the gas phase were collected on transmission electron microscope grids for Z-contrast imaging and electron energy loss spectroscopy analysis. The effects of gas flow on nanoparticle formation, photoluminescence, and collection are described. (C) 1998 American Institute of Physics. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Geohegan, DB (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. RI Duscher, Gerd/G-1730-2014; Puretzky, Alexander/B-5567-2016; Geohegan, David/D-3599-2013 OI Duscher, Gerd/0000-0002-2039-548X; Puretzky, Alexander/0000-0002-9996-4429; Geohegan, David/0000-0003-0273-3139 NR 16 TC 270 Z9 275 U1 7 U2 54 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 8 PY 1998 VL 72 IS 23 BP 2987 EP 2989 DI 10.1063/1.121516 PG 3 WC Physics, Applied SC Physics GA 108PD UT WOS:000075273900021 ER PT J AU Leppert, VJ Zhang, CJ Lee, HWH Kennedy, IM Risbud, SH AF Leppert, VJ Zhang, CJ Lee, HWH Kennedy, IM Risbud, SH TI Observation of quantum confined excited states of GaN nanocrystals SO APPLIED PHYSICS LETTERS LA English DT Article ID DEPOSITION; DIODES; TIME AB GaN nanocrystals with an average diameter of 4.5 nm+/-1.6 nm were synthesized by pulsed laser ablation of a gallium metal target in a nitrogen atmosphere. Transmission electron microscopy and selected area electron diffraction confirmed the hexagonal structure and size of the nanocrystals. Optical absorption and photoluminescence spectroscopy revealed quantum confined excited states in the nanocrystalline samples with features at 4.43 eV (280 nm) and 5.47 eV (227 nm), (C) 1998 American Institute of Physics. C1 Univ Calif Davis, Dept Chem Engn & Mat Sci, Livermore, CA 95616 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Davis, Dept Mech & Aeronaut Engn, Davis, CA 95616 USA. RP Leppert, VJ (reprint author), Univ Calif Davis, Dept Chem Engn & Mat Sci, Livermore, CA 95616 USA. NR 13 TC 27 Z9 27 U1 0 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 8 PY 1998 VL 72 IS 23 BP 3035 EP 3037 DI 10.1063/1.121532 PG 3 WC Physics, Applied SC Physics GA 108PD UT WOS:000075273900037 ER PT J AU Jia, QX Yan, F Mombourquette, C Reagor, D AF Jia, QX Yan, F Mombourquette, C Reagor, D TI Directly coupled direct current superconducting quantum interference device magnetometers based on ramp-edge Ag : YBa2Cu3O7-x/PrBa2Cu3O7-x/Ag : YBa2Cu3O7-x junctions SO APPLIED PHYSICS LETTERS LA English DT Article ID DC-SQUID MAGNETOMETERS; JOSEPHSON-JUNCTIONS; LOW-NOISE; YBA2CU3O7-X; BARRIER; LAYERS AB Directly coupled de superconducting quantum interference device (SQUID) magnetometers on LaAlO3 substrates were fabricated using ramp-edge superconductor/normal-metal/superconductor junctions, where Ag-doped YBa2Cu3O7-x was used for the electrode and PrBa2Cu3O7-x for the normal-metal barrier. A Aux noise of 8 X 10(-6) Phi(0) Hz(-1/2) at 10 kHz measured with a de bias current was achieved at 75 K, which corresponded to a field sensitivity of 400 fTHz(-1/2) for a magnetometer with a Dick-up loop area of 8.5 mmX7.5 mm. Most significantly, the noise floor increased at lower frequencies with a frequency dependence slightly less than 1/f. The field noise of the SQUID magnetometers increased by only 25% after cycling the devices from zero field to 500 mG. In a static earth's magnetic field background, the field noise of the SQUID magnetometers increased by less than a factor of 2. (C) 1998 American Institute of Physics. [S0003-6951(98)03 123-4]. C1 Univ Calif Los Alamos Natl Lab, Supercond Technol Ctr, Los Alamos, NM 87545 USA. RP Jia, QX (reprint author), Univ Calif Los Alamos Natl Lab, Supercond Technol Ctr, Mail Stop K763, Los Alamos, NM 87545 USA. RI Jia, Q. X./C-5194-2008 NR 24 TC 9 Z9 9 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 8 PY 1998 VL 72 IS 23 BP 3068 EP 3070 DI 10.1063/1.121543 PG 3 WC Physics, Applied SC Physics GA 108PD UT WOS:000075273900048 ER PT J AU Keil, UD Ha, T Jensen, JR Hvam, JM AF Keil, UD Ha, T Jensen, JR Hvam, JM TI Femtosecond tunneling response of surface plasmon polaritons SO APPLIED PHYSICS LETTERS LA English DT Article ID SCANNING PROBE MICROSCOPY; SPECTROSCOPY; FIELD; AG AB We obtain femtosecond (200 fs) time resolution using a scanning tunneling microscope on surface plasmon polaritons (SPPs) generated by two 100 fs laser beams in total internal reflection geometry. The tunneling gap dependence of the signal clearly indicates the tunneling origin of the signal and suggests that nanometer spatial resolution can be obtained together with femtosecond temporal resolution. This fast response, in contrast to the picosecond decay time of SPPs revealed by differential reflectivity measurements, can be attributed to a coherent superposition of SPPs rectified at the tunneling junction. (C) 1998 American Institute of Physics. [S0003-6951(98)02223-2]. C1 Mikroelekt Ctr, DK-2800 Lyngby, Denmark. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Sci Mat, Berkeley, CA 94720 USA. RP Keil, UD (reprint author), Mikroelekt Ctr, DK-2800 Lyngby, Denmark. EM ulli@mic.dtu.dk RI Ha, Taekjip/B-9506-2009; Hvam, Jorn/I-2987-2016 OI Ha, Taekjip/0000-0003-2195-6258; Hvam, Jorn/0000-0002-2429-1012 NR 15 TC 7 Z9 7 U1 1 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 8 PY 1998 VL 72 IS 23 BP 3074 EP 3076 DI 10.1063/1.121545 PG 3 WC Physics, Applied SC Physics GA 108PD UT WOS:000075273900050 ER PT J AU Shafizadeh, N Brechignac, P Dyndgaard, M Fillion, JH Gauyacq, D Levy, B Miller, JC Pino, T Raoult, M AF Shafizadeh, N Brechignac, P Dyndgaard, M Fillion, JH Gauyacq, D Levy, B Miller, JC Pino, T Raoult, M TI A, C, and D electronic states of the Ar-NO van der Waals molecule revisited: Experiment and theory SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MULTIPHOTON IONIZATION SPECTROSCOPY; VANDERWAALS COMPLEX; ROTATIONAL PREDISSOCIATION; NITRIC-OXIDE; PHOTOELECTRON; SPECTRA; A(2)SIGMA(+); SPECTROMETRY; TRANSITIONS; VIBRATIONS AB The A-X transition of ArNO has been reinvestigated by laser induced fluorescence (LIF) both in the bound-free and bound-bound region. The discrete part of the spectrum is at least two orders of magnitude weaker than the continuum part, indicative of a large change in geometry from the ground state. This very different configuration, both from the ground state and from the C and D states, can only be explained by strong interactions, induced by the perturbing argon atom, between the excited states of the van der Waals complex converging to the 3s sigma,A, 3p pi,C, and 3p sigma,D Rydberg states of NO. In order to quantitatively understand the observed structure of the A-X, C-X, and D-X excitation spectra, a global theoretical approach is proposed, based on ab initio calculations of the potential energy surfaces in the planar A' and A " symmetries, including a configuration interaction between the states of same symmetry. Small adjustments of the diabatic energy surfaces lead to a satisfactory agreement between the observed and calculated spectra, In contrast to the ground state, the Renner-Teller splitting of the 3p pi,C state into two A' and A " components is very large, of the order of 4000 cm(-1). This effect is complicated by further mixing between the states of A' symmetry induced by the argon atom. The A state is anisotropic and weakly bound with a small potential well at the linear configuration (the argon atom being on the side of the oxygen). The C(A ") and the bound electronic component of the strongly mixed C + D(Al) states exhibit a vibrational structure close to that of the ion and, consequently, present some Rydberg character even if the Coulomb field central symmetry (s-p) is broken by the perturbing argon atom. (C) 1998 American Institute of Physics. C1 Univ Paris Sud, CNRS, Photophys Mol Lab, F-91405 Orsay, France. Univ Cergy Pontoise, Lab Atomes & Mol Astrophys, F-95031 Cergy Pontoise, France. Univ Paris Sud, Lab Physicochim Rayonnements, F-91405 Orsay, France. Oak Ridge Natl Lab, Div Life Sci, Chem & Biol Phys Sect, Oak Ridge, TN 37831 USA. RP Gauyacq, D (reprint author), Univ Paris Sud, CNRS, Photophys Mol Lab, Bat 210, F-91405 Orsay, France. NR 37 TC 35 Z9 35 U1 1 U2 9 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 8 PY 1998 VL 108 IS 22 BP 9313 EP 9326 DI 10.1063/1.476384 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 108FT UT WOS:000075256000017 ER PT J AU Baumann, T Ramakrishnan, E Azhari, A Beene, JR Charity, RJ Dempsey, JF Halbert, ML Hua, PF Kryger, RA Mueller, PE Pfaff, R Sarantites, DG Sobotka, LG Stracener, DW Thoennessen, M Van Buren, G Varner, RL Yokoyama, S AF Baumann, T Ramakrishnan, E Azhari, A Beene, JR Charity, RJ Dempsey, JF Halbert, ML Hua, PF Kryger, RA Mueller, PE Pfaff, R Sarantites, DG Sobotka, LG Stracener, DW Thoennessen, M Van Buren, G Varner, RL Yokoyama, S TI Evolution of the giant dipole resonance in excited Sn-120 and Pb-208 nuclei populated by inelastic alpha scattering SO NUCLEAR PHYSICS A LA English DT Article DE giant dipole resonance; hot nuclei; statistical mode; inelastic alpha-scattering ID HIGH-EXCITATION ENERGIES; HOT ROTATING NUCLEI; TEMPERATURE-DEPENDENCE; WIDTH; SHAPE; FLUCTUATIONS; STATES; ISOTOPES; PHOTONS; FUSION AB The evolution of the giant dipole resonance (GDR) in Sn-120 and Pb-208 nuclei at excitation energies in the range of 30-130 MeV and 40-110 MeV, respectively, were studied by measuring high energy gamma rays from the decay of the resonance. The excited states were populated by inelastic scattering of alpha particles at beam energies of 40 and 50 MeV/nucleon for Sn-120 and 40 MeV/nucleon for Pb-208. A systematic increase of the resonance width with increasing excitation energy was observed for both nuclei. The observed width evolution was compared to calculations employing a model that adiabatically couples the collective excitation to the nuclear shape, and to a model based on the collisional damping of nucleons. The adiabatic coupling model described the width evolution in both nuclei well, whereas the collisional damping calculation could describe the width evolution only in Pb-208. Light-particle inelastic scattering populates low angular momentum states in the target nucleus. The observed width increase is therefore interpreted to be predominantly due to fluctuations in the nuclear shape induced by temperature. This interpretation is consistent with the adiabatic model calculations and with recent angular momentum-gated measurements of the GDR in excited Sn isotopes. (C) 1998 Published by Elsevier Science B.V. C1 Michigan State Univ, Natl Supercond Cyclotron Lab, E Lansing, MI 48824 USA. Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Washington Univ, Dept Chem, St Louis, MO 63130 USA. RP Baumann, T (reprint author), Michigan State Univ, Natl Supercond Cyclotron Lab, E Lansing, MI 48824 USA. OI Charity, Robert/0000-0003-3020-4998 NR 44 TC 59 Z9 60 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 JUN 8 PY 1998 VL 635 IS 4 BP 428 EP 445 DI 10.1016/S0375-9474(98)00197-3 PG 18 WC Physics, Nuclear SC Physics GA ZX478 UT WOS:000074520100002 ER PT J AU Gibson, JK AF Gibson, JK TI Gas-phase reactions of americium ion, Am+, with alkenes SO ORGANOMETALLICS LA English DT Article ID LANTHANIDE CATIONS; ORGANOMETALLIC CHEMISTRY; HYDROCARBON ACTIVATION; ELECTRONIC-STRUCTURE; ACTINIDE COMPLEXES; MASS-SPECTROMETRY; LASER-ABLATION; REACTIVITY; ALKANES; OXIDE AB The investigation of gas-phase activation of alkene C-H bonds by f-element metal ions has been extended to americium (Am+) using the technique of laser ablation with prompt reaction and detection; reactions were carried out with ethene, l-butene, 2-butene, cyclohexene, benzene, 1,5-cyclooctadiene (COD), and cyclooctatetraene (COT). The product (Am-L-*)(+) compositions and abundances were compared with those for lighter An(+) and Ln(+). For the linear and cyclic Cs alkene reactants, Am+ was found to be essentially inert-only a minuscule amount of the (Am+-benzene) condensation product was detected. Reactions with COD and COT produced the dehydrogenation complexes, {Am-C8H8}(+) and (Am-C8H6)(+), though in lower yields than for lighter An(+) Overall, the C-H activation efficacy of Am+ was smaller than that for the preceding An(+) but was closer to that of the relatively unreactive lanthanide ion Tm+. This result is interpreted to indicate that the 5f electrons of Am+, like the 4f electrons of the Ln(+), do not substantially participate in C-H (or C-C) activation. Apparently, ground-state Am+ with its [Rn]5f(7)7s(1) orbital occupancy must be excited to the [Rn]5f(6)6d(1)7s(1)-state, 245 kJ mol-l above ground, which comprises two chemically active 6d/7s electrons and is capable of forming a C-Am+-H dehydrogenation intermediate. The greatly enhanced reactivity of Am+ with COD and COT compared with the smaller alkenes can be rationalized in the context of a "curve-crossing" model for the C-H activation process. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Gibson, JK (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. NR 41 TC 17 Z9 17 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD JUN 8 PY 1998 VL 17 IS 12 BP 2583 EP 2589 DI 10.1021/om9801554 PG 7 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA ZU204 UT WOS:000074172700029 ER PT J AU Abbott, D Ahmidouch, A Amatuni, TA Armstrong, C Arrington, J Assamagan, KA Bailey, K Baker, OK Barrow, S Beard, K Beatty, D Beedoe, S Beise, E Belz, E Bochna, C Breuer, H Bruins, EEW Carlini, R Cha, J Chant, N Cothran, C Cummings, WJ Danagoulian, S Day, D DeSchepper, D Ducret, JE Duncan, F Dunne, J Dutta, D Eden, T Ent, R Fortune, HT Frolov, V Geesaman, DF Gao, H Gilman, R Gueye, P Hansen, JO Hinton, W Holt, RJ Jackson, C Jackson, HE Jones, CE Kaufman, S Kelly, JJ Keppel, C Khandaker, M Kim, W Kinney, E Klein, A Koltenuk, D Kramer, L Lorenzon, W McFarlane, K Mack, DJ Madey, R Markowitz, P Martin, J Mateos, A Meekins, D Miller, MA Milner, R Mitchell, J Mohring, R Markowitz, P Nathan, AM Niculescu, G Niculescu, I O'Neill, TG Potterveld, D Price, JW Reinhold, J Salgado, C Schiffer, JP Segel, RE Stoler, P Suleiman, R Tadevosyan, V Tang, L Terburg, B van Westrum, D Welch, P Williamson, C Wood, S Yan, C Yang, JC Yu, J Zeidman, B Zhao, W Zihlmann, B AF Abbott, D Ahmidouch, A Amatuni, TA Armstrong, C Arrington, J Assamagan, KA Bailey, K Baker, OK Barrow, S Beard, K Beatty, D Beedoe, S Beise, E Belz, E Bochna, C Breuer, H Bruins, EEW Carlini, R Cha, J Chant, N Cothran, C Cummings, WJ Danagoulian, S Day, D DeSchepper, D Ducret, JE Duncan, F Dunne, J Dutta, D Eden, T Ent, R Fortune, HT Frolov, V Geesaman, DF Gao, H Gilman, R Gueye, P Hansen, JO Hinton, W Holt, RJ Jackson, C Jackson, HE Jones, CE Kaufman, S Kelly, JJ Keppel, C Khandaker, M Kim, W Kinney, E Klein, A Koltenuk, D Kramer, L Lorenzon, W McFarlane, K Mack, DJ Madey, R Markowitz, P Martin, J Mateos, A Meekins, D Miller, MA Milner, R Mitchell, J Mohring, R Markowitz, P Nathan, AM Niculescu, G Niculescu, I O'Neill, TG Potterveld, D Price, JW Reinhold, J Salgado, C Schiffer, JP Segel, RE Stoler, P Suleiman, R Tadevosyan, V Tang, L Terburg, B van Westrum, D Welch, P Williamson, C Wood, S Yan, C Yang, JC Yu, J Zeidman, B Zhao, W Zihlmann, B TI Quasifree (e,e ' p) reactions and proton propagation in nuclei SO PHYSICAL REVIEW LETTERS LA English DT Article ID TRANSPARENCY; DEPENDENCE; C-12(E,E'P) AB The (e, e' p) reaction was studied on targets of C, Fe, and Au at momentum transfers squared Q(2) of 0.6, 1.3, 1.8, and 3.3 GeV2 in a region of kinematics dominated by quasifree electron-proton scattering. Missing energy and missing momentum distributions are reasonably well described by plane wave impulse approximation calculations with Q(2) and A dependent corrections that measure the attenuation of the final state protons. C1 Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. Argonne Natl Lab, Argonne, IL 60439 USA. CALTECH, Pasadena, CA 91125 USA. Chungnam Natl Univ, Taejon 305764, South Korea. Univ Colorado, Boulder, CO 80309 USA. Florida Int Univ, University Pk, FL 33199 USA. Hampton Univ, Hampton, VA 23668 USA. Kent State Univ, Kent, OH 44242 USA. Kyungpook Natl Univ, Taegu 702701, South Korea. Univ Illinois, Urbana, IL 61801 USA. MIT, Cambridge, MA 02139 USA. Univ Maryland, College Pk, MD 20742 USA. Norfolk State Univ, Norfolk, VA 23504 USA. N Carolina Agr & Technol State Univ, Greensboro, NC 27411 USA. Northwestern Univ, Evanston, IL 60201 USA. Oregon State Univ, Corvallis, OR 97331 USA. Old Dominion Univ, Norfolk, VA 23529 USA. Univ Penn, Philadelphia, PA 19104 USA. Rensselaer Polytech Inst, Troy, NY 12180 USA. Rutgers State Univ, New Brunswick, NJ 08903 USA. Ctr Etud Nucl Saclay, Gif Sur Yvette, France. Univ Virginia, Charlottesville, VA 22901 USA. Coll William & Mary, Williamsburg, VA 23187 USA. Yerevan Phys Inst, Yerevan 375036, Armenia. RP Abbott, D (reprint author), Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. RI Gao, Haiyan/G-2589-2011; Arrington, John/D-1116-2012; Holt, Roy/E-5803-2011; Day, Donal/C-5020-2015 OI Arrington, John/0000-0002-0702-1328; Day, Donal/0000-0001-7126-8934 NR 14 TC 62 Z9 62 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 8 PY 1998 VL 80 IS 23 BP 5072 EP 5076 DI 10.1103/PhysRevLett.80.5072 PG 5 WC Physics, Multidisciplinary SC Physics GA ZR769 UT WOS:000074011900012 ER PT J AU Wills, AA Gorczyca, TW Berrah, N Langer, B Felfli, Z Kukk, E Bozek, D Nayandin, O Alshehri, M AF Wills, AA Gorczyca, TW Berrah, N Langer, B Felfli, Z Kukk, E Bozek, D Nayandin, O Alshehri, M TI Importance of spin-orbit effects in parity-unfavored photoionization of neon, observed using a two-dimensional photoelectron imaging technique SO PHYSICAL REVIEW LETTERS LA English DT Article ID ANGULAR-DISTRIBUTION; RESONANCES; RESOLUTION; SATELLITES; STATES AB We present an experimental and theoretical study of photoexcitation and decay mechanisms of doubly excited resonances in neon. New spin-orbit induced effects are identified in the angle-resolved and photoelectron-resolved differential cross sections for a parity-unfavored transition. These observations are facilitated using a two-dimensional imaging technique, and highlight the importance of considering spin-orbit induced effects when studying detailed spectra in atomic systems as light as neon. C1 Western Michigan Univ, Dept Phys, Kalamazoo, MI 49008 USA. Max Planck Gesell, Fritz Haber Inst, D-14195 Berlin, Germany. Clark Atlanta Univ, Ctr Theoret Studies Phys Syst, Atlanta, GA 30314 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source, Berkeley, CA USA. RP Wills, AA (reprint author), Western Michigan Univ, Dept Phys, Kalamazoo, MI 49008 USA. RI Langer, Burkhard/A-6504-2013; Bozek, John/E-9260-2010 OI Bozek, John/0000-0001-7486-7238 NR 15 TC 23 Z9 23 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 8 PY 1998 VL 80 IS 23 BP 5085 EP 5088 DI 10.1103/PhysRevLett.80.5085 PG 4 WC Physics, Multidisciplinary SC Physics GA ZR769 UT WOS:000074011900015 ER PT J AU Jesson, DE Chen, G Chen, KM Pennycook, SJ AF Jesson, DE Chen, G Chen, KM Pennycook, SJ TI Self-limiting growth of strained faceted islands SO PHYSICAL REVIEW LETTERS LA English DT Article ID STRANSKI-KRASTANOV GROWTH; MICROSTRUCTURAL EVOLUTION; IN-SITU; GAAS; SI(001); GE; HETEROEPITAXY; TRANSITION; FILMS; DOTS AB We consider the growth of facets associated with coherently strained semiconductor islands. Surprisingly, the island growth rate is found to rapidly self-limit, which has important consequences for island size distributions. A new explanation for the elongation of strained faceted islands is proposed as a natural consequence of facet growth kinetics. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Jesson, DE (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. OI Jesson, David/0000-0003-0897-1445 NR 33 TC 150 Z9 152 U1 0 U2 10 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 8 PY 1998 VL 80 IS 23 BP 5156 EP 5159 DI 10.1103/PhysRevLett.80.5156 PG 4 WC Physics, Multidisciplinary SC Physics GA ZR769 UT WOS:000074011900033 ER PT J AU Ahluwalia, DV AF Ahluwalia, DV TI Can general relativistic description of gravitation be considered complete? SO MODERN PHYSICS LETTERS A LA English DT Article AB The local galactic cluster, the Great attractor, embeds us in a dimensionless gravitational potential of about -3 x 10(-5). In the solar system, this potential is constant to about 1 part in 10(11). Consequently, planetary orbits, which are determined by the gradient in the gravitational potential, remain unaffected. However, this is not so for the recently introduced flavor-oscillation clocks where the new redshift-inducing phases depend on the gravitational potential itself. On these grounds, and by studying the invariance properties of the gravitational phenomenon in the weak fields, we argue that there exists an element of incompleteness in the general relativistic description of gravitation. An incompleteness-establishing inequality is derived and an experiment is outlined to test the thesis presented. C1 Univ Calif Los Alamos Natl Lab, Phys Div P25, Los Alamos, NM 87545 USA. RP Ahluwalia, DV (reprint author), Univ Calif Los Alamos Natl Lab, Phys Div P25, Mail Stop H-846, Los Alamos, NM 87545 USA. NR 8 TC 24 Z9 24 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-7323 J9 MOD PHYS LETT A JI Mod. Phys. Lett. A PD JUN 7 PY 1998 VL 13 IS 17 BP 1393 EP 1400 DI 10.1142/S0217732398001455 PG 8 WC Physics, Nuclear; Physics, Particles & Fields; Physics, Mathematical SC Physics GA ZX463 UT WOS:000074518600007 ER PT J AU Myneni, SCB Traina, SJ Logan, TJ AF Myneni, SCB Traina, SJ Logan, TJ TI Ettringite solubility and geochemistry of the Ca(OH)(2)-Al-2(SO4)(3)-H2O system at 1 atm pressure and 298 K SO CHEMICAL GEOLOGY LA English DT Article DE ettringite; solubility; Al geochemistry; Al-sulfates ID CAO-AL2O3-CASO4-H2O SYSTEM; SULFATE RETENTION; FOREST SOILS; ALUMINUM; STABILITY; ALUNITE; WATERS; BASALUMINITE; 25-DEGREES-C; PH AB The solubility and weathering reactions of ettringite, (Ca6Al2(SO4)(3)(OH)(12).26H(2)O), were used to study the geochemical equilibria of the Ca(OH)(2)-Al-2(SO4)(3)-H2O system at environmental pH conditions. Ettringite is a stable mineral above a pH of 10.7 and dissolved congruently with a log K-sp of -111.6 (+/-0.8). Between pH 10.7 and 9.5, ettringite underwent incongruent dissolution to gypsum and Al-hydroxides and controlled Ca2+, Al3+, and SO42- activities. At near neutral pH, Al-hydroxy sulfates precipitated in addition to gypsum and AI-hydroxide. These Al-hydroxy sulfate phases exhibited prismatic and anhedral shapes and had variable Al/S ratios. In addition, some new poorly crystalline Ca-Al-hydroxy sulfate phases were identified in microscopic studies when the pH was acidic (pH similar to 5). The activities of Ca2+, Al3+, and SO42- suggest that the geochemistry of the Ca(OH)(2)-Al-2(SO4)(3)-H2O system in the pH range of 7 to 10 is simple and its component Ca(OH)(2)-SO3-H2O and Al-2(SO4)(3)-H2O systems behave independently of each other. The precipitation of Al-hydroxy sulfates below pH 7.0 significantly influenced Ca2+ and SO42- activities. This effect was pronounced when Ca-Al-hydroxy sulfate phases started precipitating (pH < 5.0). The lack of thermodynamic data on the newly identified Al, and Ca-Al-hydroxy sulfates makes it difficult to interpret the geochemistry of Ca(OH)(2)-Al-2(SO4)(3)-H2O system for pH 5.0. Reaction path calculations conducted using the EQ6 computer code predicted ion activities close to the experimental values above pH 5.0, The observed differences between thermodynamic modelling and actual experimental data below this pH can be explained by the formation of Al-/Ca-Al-hydroxy sulfate phases in the system, as detected by electron microscopy and X-ray elemental analysis. These reactions are relevant and useful to the prediction of AI, and Ca geochemistry in natural systems. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Ohio State Univ, Dept Geol Sci, Columbus, OH 43210 USA. RP Myneni, SCB (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Mail Stop 90-1116, Berkeley, CA 94720 USA. NR 59 TC 71 Z9 73 U1 0 U2 15 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2541 J9 CHEM GEOL JI Chem. Geol. PD JUN 5 PY 1998 VL 148 IS 1-2 BP 1 EP 19 DI 10.1016/S0009-2541(97)00128-9 PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA ZY360 UT WOS:000074612900001 ER PT J AU Voges, D Jap, BK AF Voges, D Jap, BK TI Recombinant expression, purification and characterization of Kch, a putative Escherichia coli potassium channel protein SO FEBS LETTERS LA English DT Article DE membrane protein; channel protein; potassium channel; Kch ID K+ CHANNEL; SUBUNIT STOICHIOMETRY; INACTIVATION; MEMBRANE AB The Escherichia coli gene kch, similar in primary structure to eukaryotic voltage-gated potassium channels, was cloned and overexpressed in E. coli. The protein was solubilized from the plasma membrane with dodecylmaltopyranoside, lauryldimethylamine oxide or N-laurylsarcosine and was purified in milligram amounts by imidazole clution from a nickel-chelate column. The molecular mass of the purified protein in a number of detergents with 12 carbon atom chains suggests that rKch forms primarily tetramers of the 50 kDa monomers. CD spectroscopy of the purified protein indicates a significant alpha-helical content that is preserved upon addition of SDS. (C) 1998 Federation of European Biochemical Societies. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP Voges, D (reprint author), Max Planck Inst Biochem, Dept Mol Struct Biol, Klopferspitz 18A, D-82152 Martinsried, Germany. FU NIGMS NIH HHS [GM-51487] NR 18 TC 8 Z9 8 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0014-5793 J9 FEBS LETT JI FEBS Lett. PD JUN 5 PY 1998 VL 429 IS 1 BP 104 EP 108 DI 10.1016/S0014-5793(98)00509-2 PG 5 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA ZU956 UT WOS:000074253400021 PM 9657392 ER PT J AU Ruscetti, T Lehnert, BE Halbrook, J Le Trong, H Hoekstra, MF Chen, DJ Peterson, SR AF Ruscetti, T Lehnert, BE Halbrook, J Le Trong, H Hoekstra, MF Chen, DJ Peterson, SR TI Stimulation of the DNA-dependent protein kinase by poly(ADP-ribose) polymerase SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID STRAND-BREAK-REPAIR; V(D)J RECOMBINATION; BINDING-PROTEIN; CATALYTIC SUBUNIT; KU AUTOANTIGEN; END-BINDING; NUCLEAR; INHIBITION; CELLS; PK AB The DNA-dependent protein kinase (DNA-PK) is a heterotrimeric enzyme that binds to double-stranded DNA and is required for the rejoining of double-stranded DNA breaks in mammalian cells. It has been proposed that DNA-PK functions in this DNA repair pathway by binding to the ends of broken DNA molecules and phosphorylating proteins that bind to the damaged DNA ends. Another enzyme that binds to DNA strand breaks and may also function in the cellular response to DNA damage is the poly(ADP-ribose) polymerase (PARP), Here, we show that PARP can be phosphorylated by purified DNA-PK, and the catalytic subunit of DNA-PK is ADP-ribosylated by PARP, The protein kinase activity of DNA-PK can be stimulated by PARP in the presence of NAD(+) in a reaction that is blocked by the PARP inhibitor 1,5-dihydroxyiso-quinoline. The stimulation of DNA-PK by PARP-mediated protein ADP-ribosylation occurs independent of the Ku70/80 complex. Taken together, these results show that PARP can modify the activity of DNA-PK in vitro and suggest that these enzymes may function coordinately in vivo in response to DNA damage. C1 Univ Calif Los Alamos Natl Lab, Cell & Mol Biol Grp LS4, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Life Sci, DNA Damage & Repair Grp LS6, Los Alamos, NM 87545 USA. ICOS Corp, Bothell, WA 98021 USA. RP Peterson, SR (reprint author), Mail Stop M888, Los Alamos, NM 87545 USA. FU NCI NIH HHS [CA50519] NR 53 TC 165 Z9 172 U1 0 U2 4 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 JUN 5 PY 1998 VL 273 IS 23 BP 14461 EP 14467 DI 10.1074/jbc.273.23.14461 PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA ZR856 UT WOS:000074021500061 PM 9603959 ER PT J AU Goldman, M Pruitt, L AF Goldman, M Pruitt, L TI Comparison of the effects of gamma radiation and low temperature hydrogen peroxide gas plasma sterilization on the molecular structure, fatigue resistance, and wear behavior of UHMWPE SO JOURNAL OF BIOMEDICAL MATERIALS RESEARCH LA English DT Article DE UHMWPE; plasma sterilization; gamma sterilization; structure; fatigue; wear; gas sterilization; low temperature sterilization ID WEIGHT POLYETHYLENE; IRRADIATION; CRACKS AB The effects of gamma radiation and low temperature hydrogen peroxide gas plasma (HPGP) sterilization on structure and cyclic mechanical properties were examined for orthopedic grade ultra-high-molecular-weight polyethylene (UHMWPE) and compared to each other as well as to no sterilization (control). Density was monitored with a density gradient column and was found to be directly influenced by the sterilization method employed: Gamma radiation led to an increase, while plasma did not. Oxidation of the polymer was studied by observing changes in the carbonyl peak with Fourier transform infrared spectrometry and was found to be strongly affected by both gamma radiation and subsequent aging, awhile plasma sterilization had little effect. Gamma radiation resulted in embrittlement of the polymer and a decreased resistance to fatigue crack propagation. This mechanical degradation was a direct consequence of postradiation oxidation and molecular evolution of the polymer and was not observed in the plasma-sterilized polymer. Both gamma radiation and plasma sterilization led to improved wear performance of the UHMWPE compared to the nonsterile control material. (C) 1998 John Wiley & Sons, Inc. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mech Engn, Berkeley, CA 94720 USA. RP Goldman, M (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 21 TC 89 Z9 90 U1 0 U2 9 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0021-9304 J9 J BIOMED MATER RES JI J. Biomed. Mater. Res. PD JUN 5 PY 1998 VL 40 IS 3 BP 378 EP 384 DI 10.1002/(SICI)1097-4636(19980605)40:3<378::AID-JBM6>3.0.CO;2-C PG 7 WC Engineering, Biomedical; Materials Science, Biomaterials SC Engineering; Materials Science GA ZJ364 UT WOS:000073207100006 PM 9570068 ER PT J AU Ben-Naim, E Bishop, AR Daruka, I Krapivsky, PL AF Ben-Naim, E Bishop, AR Daruka, I Krapivsky, PL TI Mean-field theory of polynuclear surface growth SO JOURNAL OF PHYSICS A-MATHEMATICAL AND GENERAL LA English DT Article ID DIRECTED POLYMERS; CRYSTAL-GROWTH; DOMAIN-STRUCTURE; ORDER PARAMETER; RANDOM-MEDIA; NUCLEATION; INTERFACES; EVOLUTION; FLUCTUATIONS; KINETICS AB We study statistical properties of a continuum model of polynuclear surface growth on an infinite substrate. We develop a self-consistent mean-field theory which is solved to deduce the growth velocity and the extremal behaviour of the coverage. Numerical simulations show that this theory gives an improved approximation for the coverage compared to the previous linear recursion relations approach. Furthermore, these two approximations provide useful upper and lower bounds for a number of characteristics including the coverage, growth velocity and the width exponent. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. Boston Univ, Ctr Polymer Studies, Boston, MA 02215 USA. Boston Univ, Dept Phys, Boston, MA 02215 USA. RP Ben-Naim, E (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RI Ben-Naim, Eli/C-7542-2009; Krapivsky, Pavel/A-4612-2014 OI Ben-Naim, Eli/0000-0002-2444-7304; NR 35 TC 14 Z9 14 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0305-4470 J9 J PHYS A-MATH GEN JI J. Phys. A-Math. Gen. PD JUN 5 PY 1998 VL 31 IS 22 BP 5001 EP 5012 DI 10.1088/0305-4470/31/22/005 PG 12 WC Physics, Multidisciplinary; Physics, Mathematical SC Physics GA ZU418 UT WOS:000074195100005 ER PT J AU Fowler, JS Volkow, ND Logan, J Pappas, N King, P MacGregor, R Shea, C Garza, V Gatley, SJ AF Fowler, JS Volkow, ND Logan, J Pappas, N King, P MacGregor, R Shea, C Garza, V Gatley, SJ TI An acute dose of nicotine does not inhibit MAO B in baboon brain in vivo SO LIFE SCIENCES LA English DT Article DE nicotine; MAO B; positron emission tomography; tobacco smoke ID MONOAMINE-OXIDASE-B; POSITRON EMISSION TOMOGRAPHY; PARKINSONS-DISEASE; ENDOGENOUS DOPAMINE; ALZHEIMERS-DISEASE; CIGARETTE SMOKERS; L-DEPRENYL; SMOKING; TOBACCO; BINDING AB Tobacco smoke exposure has been shown to inhibit brain and platelet MAO B in animals and in humans. Though the mechanism(s) responsible for MAO B inhibition are not known, studies in rodents have shown that nicotine administration does not inhibit brain MAO B. In this study we investigated whether brain MAO B is also unaffected by nicotine in the living primate. Brain MAO B was measured with posit-ron emission tomography (PET) and deuterium substituted [C-11]L-deprenyl ([C-11]L-deprenyl-D2) in three baboons at baseline and 5 minutes after the injection of (-)-nicotine (0.3 mg administered intravenously). A three-compartment model was used to calculate the plasma to brain transfer constant K1 which is related to blood flow, and lambda k3, which is a function of the concentration of catalytically active MAO B molecules. Nicotine administration did not produce significant changes in either of these parameters. This study in living baboons confirms previous studies in rodents and solidifies the notion that other mechanisms for MAO B inhibition observed in smokers need to be considered. (C) 1998 Elsevier Science Inc. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Fowler, JS (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. FU NINDS NIH HHS [NS 15380] NR 33 TC 12 Z9 12 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0024-3205 J9 LIFE SCI JI Life Sci. PD JUN 5 PY 1998 VL 63 IS 2 BP PL19 EP PL23 DI 10.1016/S0024-3205(98)00251-3 PG 5 WC Medicine, Research & Experimental; Pharmacology & Pharmacy SC Research & Experimental Medicine; Pharmacology & Pharmacy GA ZT841 UT WOS:000074133200010 PM 9674950 ER PT J AU Khrebtukova, I Michaud, EJ Foster, CM Stark, KL Garfinkel, DJ Woychik, RP AF Khrebtukova, I Michaud, EJ Foster, CM Stark, KL Garfinkel, DJ Woychik, RP TI Utilization of microhomologous recombination in yeast to generate targeting constructs for mammalian genes SO MUTATION RESEARCH-FUNDAMENTAL AND MOLECULAR MECHANISMS OF MUTAGENESIS LA English DT Article DE microhomologous recombination; yeast; targeting construct; targeted mutagenesis; mouse mutation; functional genomics ID EMBRYONIC STEM-CELLS; POLYCYSTIC KIDNEY-DISEASE; SACCHAROMYCES-CEREVISIAE; HOMOLOGOUS RECOMBINATION; SHUTTLE VECTORS; MOUSE; MICE; MUTAGENESIS; REPLACEMENT; DELETION AB We have developed a new procedure utilizing microhomologous recombination in yeast to generate targeting constructs for producing targeted mutations in mice. This procedure is rapid and efficient, and should be directly applicable to all mammalian genes. Moreover, only minimal information about the locus being targeted is required. The feasibility of this approach was demonstrated by producing another allele of the mouse Tg737 polycystic kidney gene. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Case Western Reserve Univ, Rainbow Babies & Childrens Hosp, Dept Pediat, Cleveland, OH 44106 USA. Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. NCI, Frederick Canc Res & Dev Ctr, ABL Basic Res Program, Gene Regulat & Chromosome Biol Lab, Frederick, MD 21702 USA. RP Case Western Reserve Univ, Rainbow Babies & Childrens Hosp, Dept Pediat, 11100 Euclid Ave, Cleveland, OH 44106 USA. EM rpw@po.cwru.edu NR 40 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0027-5107 EI 1873-135X J9 MUTAT RES-FUND MOL M JI Mutat. Res.-Fundam. Mol. Mech. Mutagen. PD JUN 5 PY 1998 VL 401 IS 1-2 BP 11 EP 25 DI 10.1016/S0027-5107(98)00053-0 PG 15 WC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology SC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology GA ZY520 UT WOS:000074630000002 PM 9639665 ER PT J AU Book, LD Arnett, DC Hu, HB Scherer, NF AF Book, LD Arnett, DC Hu, HB Scherer, NF TI Ultrafast pump-probe studies of excited-state charge-transfer dynamics in blue copper proteins SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article; Proceedings Paper CT 3rd Femtochemistry Conference (Femtochemistry 97) CY AUG 31-SEP 04, 1997 CL LUND, SWEDEN ID BIOLOGICAL ELECTRON-TRANSFER; RESONANCE RAMAN INTENSITIES; POLAR SOLVATION DYNAMICS; TIME-DOMAIN; PLASTOCYANIN; SPECTROSCOPY; CERULOPLASMIN; TEMPERATURE; ABSORPTION; COORDINATE AB We report the results of ultrafast pump-probe measurements on three blue copper proteins: spinach plastocyanin, poplar plastocyanin, and human ceruloplasmin. Electronic population dynamics and vibrational coherences involving d --> d transitions of the blue copper active site are observed using both wavelength-integrated and wavelength-resolved detection. Depending on the protein and the method of detection, the pump-induced bleaches of the electronic ground state decay with time constants of 230-300 fs. The pump-probe signals are modulated by oscillations that correspond to vibrational coherences induced by the ultrashort pulses. The frequencies of some of these oscillations can be matched with modes observed in resonance Raman studies of these proteins. For spinach plastocyanin and ceruloplasmin, wavelength-resolved signals reveal a previously unreported vibration at similar to 500 cm(-1) whose decay dynamics are consistent with the excited-state lifetime. The origin of this mode is argued to result from Duschinsky rotation. The relevance of these pump-probe results to the development of a model for biological electron transport;in these proteins is discussed. C1 Univ Chicago, Dept Chem, Chicago, IL 60637 USA. Univ Chicago, James Franck Inst, Chicago, IL 60637 USA. Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Univ Penn, Dept Chem, Philadelphia, PA 19104 USA. RP Scherer, NF (reprint author), Univ Chicago, Dept Chem, 5735 S Ellis Ave, Chicago, IL 60637 USA. NR 53 TC 54 Z9 56 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 JUN 4 PY 1998 VL 102 IS 23 BP 4350 EP 4359 DI 10.1021/jp9802634 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZU017 UT WOS:000074152900037 ER PT J AU Conboy, JC Olson, EJC Adams, DM Kerimo, J Zaban, A Gregg, BA Barbara, PF AF Conboy, JC Olson, EJC Adams, DM Kerimo, J Zaban, A Gregg, BA Barbara, PF TI Impact of solvent vapor annealing on the morphology and photophysics of molecular semiconductor thin films SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID 3,4,9,10-PERYLENETETRACARBOXYLIC DIANHYDRIDE PTCDA; SCANNING OPTICAL MICROSCOPY; ORGANIC SOLAR-CELLS; PHOTOVOLTAIC PROPERTIES; PHOTOELECTROCHEMICAL CHARACTERIZATION; EXTENDED EXCITONS; PHTHALOCYANINE; CRYSTALLOCHROMY; PHOTOCURRENT; DERIVATIVES AB The effect of solvent vapor annealing on the fluorescence properties and morphology of titanyl phthalocyanine/ perylene phenethylimide thin-film molecular semiconductor bilayers (TiOPc/PPEI) is investigated. A combination of atomic force microscopy (AFM) and near-field scanning optical microscopy (NSOM) is used in conjunction with bulk absorption and fluorescence measurements to correlate the morphological and photophysical properties of these bilayer systems. AFM data show that treatment of the vacuum-deposited amorphous PPEI and TiOPc/PPEI films results in the crystalline transformation of these materials and severely alters the contact between the TiOPc and PPEI layers. AFM data show extended solvent vapor annealing produces void spaces in the TiOPc coverage on the order of several hundred nanometers. Steady-state fluorescence intensity and fluorescence lifetime measurements are used as a measure of charge-transfer quenching efficiencies. Very efficient charge-transfer quenching is observed when amorphous layers of TiOPc are deposited onto PPEI resulting from uniform contact between the layers. Extended annealing results in decreased charge-transfer quenching efficiencies as a result of widely dispersed, localized interfacial contact points. C1 Univ Minnesota, Dept Chem, Minneapolis, MN 55455 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Barbara, PF (reprint author), Univ Minnesota, Dept Chem, 207 Pleasant St SE, Minneapolis, MN 55455 USA. NR 46 TC 102 Z9 103 U1 4 U2 59 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 JUN 4 PY 1998 VL 102 IS 23 BP 4516 EP 4525 DI 10.1021/jp980969y PG 10 WC Chemistry, Physical SC Chemistry GA ZU021 UT WOS:000074153300010 ER PT J AU Gamble, L Henderson, MA Campbell, CT AF Gamble, L Henderson, MA Campbell, CT TI Organofunctionalization of TiO2(110): (3,3,3-trifluoropropyl)trimethoxysilane adsorption SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID FLUOROALKYL-FUNCTIONAL SILANES; SURFACE MODIFICATION; ALIPHATIC-ALCOHOLS; FORMIC-ACID; DECOMPOSITION; WATER; CHEMISTRY; OXYGEN; GLASS; FILMS AB The interaction of (3,3,3-trifluoropropyl)trimethoxysilane (FPTS), or CF3CH2CH2Si(OCH3)(3), with TiO2(110) has been studied using temperature-programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), and static secondary ion spectrometry (SSIMS). The FPTS dissociatively adsorbed on the TiO2(110), forming adsorbed CF3CH2CH2SiOCH3 and -OCH3 groups. An isotopically (O-18) enriched surface was used to show that the CF3CH2CH2SiOCH3 species was bound to the surface via two Si-O(surface) bonds, by using SSIMS to identify (SiO)-O-18 bond formation. The two -OCH3 groups eliminated from the FPTS were bound to surface Ti4+ sites. When no surface hydroxyls were present, the -OCH3 ligands, whether bound to Ti4+ or Si, decomposed at similar to 550-600 K to form methane, formaldehyde, and methanol gases. In the presence of water, the -OCH3 bound to Ti4+ sites combined with the surface hydroxyls and desorbed as methanol at similar to 300K. The CF3CH2CH2-ligand decomposed at similar to 620 K via two elimination pathways. Either the H was eliminated from the beta-carbon to form CF3CH=CH2 gas or the CF3 group was eliminated to release CH2-CH2 gas. This methoxysilane was more reactive with TiO2(110) than several ethoxysilanes previously studied. C1 Univ Washington, Dept Chem, Seattle, WA 98195 USA. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Campbell, CT (reprint author), Univ Washington, Dept Chem, Seattle, WA 98195 USA. NR 33 TC 27 Z9 27 U1 0 U2 16 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 JUN 4 PY 1998 VL 102 IS 23 BP 4536 EP 4543 DI 10.1021/jp9725386 PG 8 WC Chemistry, Physical SC Chemistry GA ZU021 UT WOS:000074153300012 ER PT J AU Hierlemann, A Campbell, JK Baker, LA Crooks, RM Ricco, AJ AF Hierlemann, A Campbell, JK Baker, LA Crooks, RM Ricco, AJ TI Structural distortion of dendrimers on gold surfaces: A tapping-mode AFM investigation SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID RECONSTRUCTION; MICROSCOPY; IMAGES; FILMS; STM C1 Texas A&M Univ, Dept Chem, College Stn, TX 77842 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Crooks, RM (reprint author), Texas A&M Univ, Dept Chem, POB 300012, College Stn, TX 77842 USA. RI Hierlemann, Andreas/A-7046-2008; Baker, Lane/B-6452-2008; Ricco, Antonio/A-5273-2010 OI Hierlemann, Andreas/0000-0002-3838-2468; NR 22 TC 181 Z9 182 U1 1 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 JUN 3 PY 1998 VL 120 IS 21 BP 5323 EP 5324 DI 10.1021/ja974283f PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA ZT015 UT WOS:000074039100026 ER PT J AU Musgrave, KB Angove, HC Burgess, BK Hedman, B Hodgson, KO AF Musgrave, KB Angove, HC Burgess, BK Hedman, B Hodgson, KO TI All-ferrous titanium(III) citrate reduced Fe protein of nitrogenase: An XAS study of electronic and metrical structure SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID AZOTOBACTER-VINELANDII NITROGENASE; RAY-ABSORPTION-SPECTROSCOPY; IRON PROTEIN; K-EDGE; COMPLEXES; COVALENCY; CLUSTER; EXAFS C1 Univ Calif Irvine, Dept Biochem & Mol Biol, Irvine, CA 92697 USA. Stanford Synchrotron Radiat Lab, Stanford, CA 94305 USA. Stanford Univ, Dept Chem, Stanford, CA 94305 USA. RP Burgess, BK (reprint author), Univ Calif Irvine, Dept Biochem & Mol Biol, Irvine, CA 92697 USA. NR 21 TC 50 Z9 50 U1 2 U2 12 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD JUN 3 PY 1998 VL 120 IS 21 BP 5325 EP 5326 DI 10.1021/ja980598z PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA ZT015 UT WOS:000074039100027 ER PT J AU Peng, XG Wickham, J Alivisatos, AP AF Peng, XG Wickham, J Alivisatos, AP TI Kinetics of II-VI and III-V colloidal semiconductor nanocrystal growth: "Focusing" of size distributions SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID INP QUANTUM DOTS; CLUSTERS; PRECURSORS; SURFACE; SOLIDS C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Alivisatos, AP (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Alivisatos , Paul /N-8863-2015; peng, xiaogang/R-6184-2016 OI Alivisatos , Paul /0000-0001-6895-9048; peng, xiaogang/0000-0002-5606-8472 NR 20 TC 1339 Z9 1371 U1 42 U2 372 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 JUN 3 PY 1998 VL 120 IS 21 BP 5343 EP 5344 DI 10.1021/ja9805425 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA ZT015 UT WOS:000074039100036 ER PT J AU Saribas, AS Valkova-Valchanova, M Tokito, MK Zhang, ZL Berry, EA Daldal, F AF Saribas, AS Valkova-Valchanova, M Tokito, MK Zhang, ZL Berry, EA Daldal, F TI Interactions between the cytochrome b, cytochrome c(1), and Fe-S protein subunits at the ubihydroquinone oxidation site of the bc(1) complex of Rhodobacter capsulatus SO BIOCHEMISTRY LA English DT Article ID IRON-SULFUR SUBUNIT; C REDUCTASE; MITOCHONDRIAL UBIQUINOL; QUINOL OXIDATION; BC1 COMPLEX; Q(O) SITE; OXIDOREDUCTASE; SPHAEROIDES; CRYSTALLIZATION; RESISTANCE AB Ubihydroquinone:cytochrome (cyt) c oxidoreductase (bc(1) complex and its plant counterpart b(6)f complex) is a vital component of energy-transducing systems in most organisms from bacteria to eukaryotes. In the facultative phototrophic (Ps) bacterium Rhodobacter capsulatus, it is constituted by the cyt b, cyt c(1), and Rieske Fe-S protein subunits and is essential for Ps growth. Of these subunits, cyt b has two nontransmembrane helices, cd1 and cd2, which are critical for its structure and function. In particular, substitution of threonine (T) at position 163 on cd1 with phenylalanine (F) or proline (P) leads to the absence of the bc(1) complex. Here, Ps(+) revertants of B:T163F were obtained, and their detailed characterizations indicated that position 163 is important for the assembly of the bc(1) complex by mediating subunit interactions at the Q(o) site. The loss of the hydroxyl group at position 163 of cyt b was compensated for by the gain of either a hydroxyl group at position 182 of cyt b or 46 of the Fe-S protein or a sulfhydryl group at position 46 of cyt c(1). Examination of the mitochondrial bc(1) complex crystal structure [Zhang, Z., Huang, L., Shulmeister, V. M., Chi, Y.-I,, Kim, K. K., Hung, L.-W., Crofts, A. R., Berry, E. A., and Kim, S.-H. (1998) Nature 392, 677-684] revealed that the counterparts of B:G182 (i.e., G167) and F:A46 (i.e., A70) are located close to B:T163 (i.e., T148), whereas the C:R46 (i.e., R28) is remarkably far from it. The revertants contained substoichiometric amounts of the Fe-S protein subunit and exhibited steady-state and single-turnover, electron transfer activities lower than that of a wild-type bc(1) complex. Interestingly, their membrane supernatants contained a smaller form of this subunit with physicochemical properties identical to those of its membrane-bound form. Determination of the amino-terminal amino acid sequence of this soluble Fe-S protein revealed that it was derived from the wild-type protein by proteolytic cleavage at V44. This work revealed for the first time that position 163 of cyt b is important both for proper subunit interactions at the Q(o) site and for inactivation of the bc(1) complex by proteolytic cleavage of its Fe-S protein subunit at a region apparently responsible for its mobility during Q(o) site catalysis. C1 Univ Penn, Dept Biol, Inst Plant Sci, Philadelphia, PA 19104 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Daldal, F (reprint author), Univ Penn, Dept Biol, Inst Plant Sci, Philadelphia, PA 19104 USA. FU NIDDK NIH HHS [DK44842]; NIGMS NIH HHS [R01 GM038237, GM 38237] NR 45 TC 26 Z9 27 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD JUN 2 PY 1998 VL 37 IS 22 BP 8105 EP 8114 DI 10.1021/bi973146s PG 10 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA ZT215 UT WOS:000074061600023 PM 9609705 ER PT J AU Eckel, RH Krauss, RM AF Eckel, RH Krauss, RM CA AHA Nutr Comm TI American Heart Association call to action: Obesity as a major risk factor for coronary heart disease SO CIRCULATION LA English DT News Item C1 Univ Colorado, Hlth Sci Ctr, Gen Clin Res Ctr, Denver, CO 80262 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Eckel, RH (reprint author), Univ Colorado, Hlth Sci Ctr, Gen Clin Res Ctr, 4200 E 9th Ave, Denver, CO 80262 USA. NR 0 TC 452 Z9 466 U1 3 U2 13 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 USA SN 0009-7322 J9 CIRCULATION JI Circulation PD JUN 2 PY 1998 VL 97 IS 21 BP 2099 EP 2100 PG 2 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA ZR296 UT WOS:000073959900001 PM 9626167 ER PT J AU Chow, E Heroux, MA AF Chow, E Heroux, MA TI An object-oriented framework for block preconditioning SO ACM TRANSACTIONS ON MATHEMATICAL SOFTWARE LA English DT Article DE block matrices; preconditioners ID ITERATIVE METHODS; EQUATIONS AB General software for preconditioning the iterative solution of linear systems is greatly lagging behind the literature. This is partly because specific problems need specific matrix and preconditioner data structures in order to be solved efficiently, i.e., multiple implementations of a preconditioner with specialized data structures are required. This article presents a framework to support preconditioning with various, possibly user-defined, data structures for matrices that are partitioned into blocks. The main idea is to define data structures for the blocks, and an upper layer of software which uses these blocks transparently of their data structure. This transparency can be accomplished by using an object-oriented language. Thus, various preconditioners, such as block relaxations and block-incomplete factorizations, only need to be defined once and will work with any block type. In addition, it is possible to transparently interchange various approximate or exact techniques for inverting pivot blocks, or solving systems whose coefficient matrices are diagonal blocks. This leads to a rich variety of preconditioners that can be selected. Operations with the blocks are performed with optimized libraries or fundamental data types. Comparisons with an optimized Fortran 77 code on both workstations and Gray supercomputers show that this framework can approach the efficiency of Fortran 77, as long as suitable block sizes and block types are chosen. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Silicon Graph Inc, Cray Res, Math Algorithms & Scalable Comp Grp, Eagan, MN 55121 USA. RP Chow, E (reprint author), Univ Calif Lawrence Livermore Natl Lab, L-560,Box 808, Livermore, CA 94551 USA. EM echow@llnl.gov; mamh@cray.com OI Heroux, Michael/0000-0002-5893-0273 NR 32 TC 28 Z9 29 U1 0 U2 0 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036 USA SN 0098-3500 J9 ACM T MATH SOFTWARE JI ACM Trans. Math. Softw. PD JUN PY 1998 VL 24 IS 2 BP 159 EP 183 DI 10.1145/290200.287639 PG 25 WC Computer Science, Software Engineering; Mathematics, Applied SC Computer Science; Mathematics GA 149MM UT WOS:000077609300001 ER PT J AU Bischof, CH Quintana-Orti, G AF Bischof, CH Quintana-Orti, G TI Computing rank-revealing QR factorizations of dense matrices SO ACM TRANSACTIONS ON MATHEMATICAL SOFTWARE LA English DT Article ID DECOMPOSITION AB We develop algorithms and implementations for computing rank-revealing QR (RRQR) factorizations of dense matrices. First, we develop an efficient block algorithm for approximating an RRQR factorization, employing a windowed version of the commonly used Golub pivoting strategy, aided by incremental condition estimation. Second, we develop efficiently implementable variants of guaranteed reliable RRQR algorithms for triangular matrices originally suggested by Chandrasekaran and Ipsen and by Pan and Tang. We suggest algorithmic improvements with respect to condition estimation, termination criteria, and Givens updating. By combining the block algorithm with one of the triangular postprocessing steps, we arrive at an efficient and reliable algorithm for computing an RRQR factorization of a dense matrix. Experimental results on IBM RS/6000 and SGI R8000 platforms show that this approach performs up to three times faster than the less reliable QR factorization with column pivoting as it is currently implemented in LAPACK, and comes within 15% of the performance of the LAPACK block algorithm for computing a QR factorization without any column exchanges. Thus, we expect this routine to be useful in many circumstances where numerical rank deficiency cannot be ruled out, but currently has been ignored because of the computational cost of dealing with it. C1 Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. Univ Jaime I, Dept Informat, Castellon 46071, Spain. RP Bischof, CH (reprint author), Argonne Natl Lab, Div Math & Comp Sci, 9700 S Cass Ave,Bldg 221, Argonne, IL 60439 USA. RI Bischof, Christian/D-2897-2009 NR 42 TC 54 Z9 54 U1 0 U2 1 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036 USA SN 0098-3500 J9 ACM T MATH SOFTWARE JI ACM Trans. Math. Softw. PD JUN PY 1998 VL 24 IS 2 BP 226 EP 253 DI 10.1145/290200.287637 PG 28 WC Computer Science, Software Engineering; Mathematics, Applied SC Computer Science; Mathematics GA 149MM UT WOS:000077609300004 ER PT J AU Bischof, CH Quintana-Orti, G AF Bischof, CH Quintana-Orti, G TI Algorithm 782: Codes for rank-revealing QR factorizations of dense matrices SO ACM TRANSACTIONS ON MATHEMATICAL SOFTWARE LA English DT Article DE block algorithm; numerical rank; rank-revealing QR factorization AB This article describes a suite of codes as well as associated testing and timing drivers for computing rank-revealing QR (RRQR) factorizations of dense matrices. The main contribution is an efficient block algorithm for approximating an RRQR factorization, employing a windowed version of the commonly used Golub pivoting strategy and improved versions of the RRQR algorithms for triangular matrices originally Suggested by Chandrasekaran and Ipsen and by Pan and Tang, respectively. We highlight usage and features of these codes. C1 Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. Univ Jaime I, Dept Informat, Castellon 46071, Spain. RP Bischof, CH (reprint author), Argonne Natl Lab, Div Math & Comp Sci, 9700 S Cass Ave,Bldg 221, Argonne, IL 60439 USA. RI Bischof, Christian/D-2897-2009 NR 3 TC 23 Z9 23 U1 2 U2 4 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036 USA SN 0098-3500 J9 ACM T MATH SOFTWARE JI ACM Trans. Math. Softw. PD JUN PY 1998 VL 24 IS 2 BP 254 EP 257 DI 10.1145/290200.287638 PG 4 WC Computer Science, Software Engineering; Mathematics, Applied SC Computer Science; Mathematics GA 149MM UT WOS:000077609300005 ER PT J AU Parkin, S Hope, H AF Parkin, S Hope, H TI Uric acid dihydrate revisited SO ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE LA English DT Article AB At 120 K, crystals of pure laboratory-grown uric acid dihydrate [7,9-dihydro-lH-purine-2,6,8(3H)-trione dihydrate], C5H4N4O3.2H(2)O, are monoclinic, P2(1)/c, with a = 7.237(3), b = 6.363(4), c = 17.449(11) Angstrom, beta = 90.51(1)degrees, Z = 4, wR(2) (all data) = 0.1094, R-1 = 0.0406 for data with I > 2 sigma(I). The crystals exhibit pseudo-orthorhombic twinning with refined twin fractions of 0.89 and 0.11. Within each twin, disorder about a noncrystallographic twofold exists with refined occupancies of 0.83 and 0.17. Packing consists of layers of hydrogen-bonded uric acid separated by layers of hydrogen-bonded water. The epitaxy of uric acid dihydrate with its anhydrous counterpart is readily explicable from the refined model. Treatment of the structure as twinned and disordered in space group P2(1)/c fully accounts for well documented violations of systematic absences in orthorhombic space groups. C1 Univ Calif Lawrence Livermore Natl Lab, Mol & Struct Biol Div, Biol & Biotechnol Res Program, Livermore, CA 94550 USA. Univ Calif Davis, Dept Chem, Livermore, CA 95616 USA. RP Parkin, S (reprint author), Duke Univ, Dept Biochem, Durham, NC 27710 USA. RI Parkin, Sean/E-7044-2011 NR 20 TC 18 Z9 18 U1 1 U2 5 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0108-7681 J9 ACTA CRYSTALLOGR B JI Acta Crystallogr. Sect. B-Struct. Sci. PD JUN 1 PY 1998 VL 54 BP 339 EP 344 DI 10.1107/S0108768197015218 PN 3 PG 6 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA ZW589 UT WOS:000074426900017 ER PT J AU Jarzynski, C AF Jarzynski, C TI Equilibrium free energies from nonequilibrium processes SO ACTA PHYSICA POLONICA B LA English DT Article; Proceedings Paper CT Marian Smoluchowski Symposium on Statistical Physics CY SEP 01-10, 1997 CL ZAKOPANE, POLAND AB A recent result, relating the (irreversible) work performed on a system during. a non-quasistatic process, to the Helmholtz free energy difference between two equilibrium states of the system, is discussed. A proof of this result is given for the special case when the evolution of the system in question is modelled by a Langevin equation in configuration space. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Jarzynski, C (reprint author), Univ Calif Los Alamos Natl Lab, T-6,MS B288, Los Alamos, NM 87545 USA. EM chrisj@t6-serv.lanl.gov RI Jarzynski, Christopher/B-4490-2009 OI Jarzynski, Christopher/0000-0002-3464-2920 NR 9 TC 25 Z9 25 U1 1 U2 5 PU ACTA PHYSICA POLONICA B, JAGELLONIAN UNIV, INST PHYSICS PI KRAKOW PA REYMONTA 4, 30-059 KRAKOW, POLAND SN 0587-4254 J9 ACTA PHYS POL B JI Acta Phys. Pol. B PD JUN PY 1998 VL 29 IS 6 BP 1609 EP 1622 PG 14 WC Physics, Multidisciplinary SC Physics GA ZV122 UT WOS:000074271600008 ER PT J AU Maziasz, PJ AF Maziasz, PJ TI ASM Gas Turbine Materials Technology Conference SO ADVANCED MATERIALS & PROCESSES LA English DT Editorial Material C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 0026-0665 J9 ADV MATER PROCESS JI Adv. Mater. Process. PD JUN PY 1998 VL 153 IS 6 BP 6 EP 6 PG 1 WC Materials Science, Multidisciplinary SC Materials Science GA ZT878 UT WOS:000074137600003 ER PT J AU Otaigbe, JU Noid, DW Sumpter, B AF Otaigbe, JU Noid, DW Sumpter, B TI Gas atomization of polymers. II. Computational neural network modeling SO ADVANCES IN POLYMER TECHNOLOGY LA English DT Article ID MULTILAYER FEEDFORWARD NETWORKS; CONTROL-SYSTEMS; APPROXIMATION; DESIGN AB A novel gas atomization process (GAP) was designed for mass producing high-quality spherical powders from molten polymers. The dependence of the powder characteristics, such as particle size and size distribution on the GAP control variables, and physical properties of the polymers were determined experimentally. Statistical and computational neural network analyses were applied to the data in both the forward and reverse modes, leading to models for predicting the particle size distribution from the process variables and vice versa. The computational neural network (CNN) model predicts an increase in the weight fraction of the smallest particle size range (0-53 mu m) by increasing the polymer melt temperature while decreasing the polymer melt stream size for the more crystalline polyethylene-based material studied. Comparisons of the CNN model predictions with experimental data yields good agreement and demonstrates that the CNN can be used to qualitatively design new experiments for the production of spherical powders from molten polymers, thereby reducing the amount of experimental work required to optimize the process. (C) 1998 John Wiley & Sons, Inc. C1 Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Otaigbe, JU (reprint author), Iowa State Univ, Dept Mat Sci & Engn, 3053 Gilman Hall, Ames, IA 50011 USA. RI Sumpter, Bobby/C-9459-2013 OI Sumpter, Bobby/0000-0001-6341-0355 NR 58 TC 1 Z9 1 U1 1 U2 2 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0730-6679 J9 ADV POLYM TECH JI Adv. Polym. Technol. PD SUM PY 1998 VL 17 IS 2 BP 161 EP 173 PG 13 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA ZJ563 UT WOS:000073229300006 ER PT J AU Lue, L Prausnitz, JM AF Lue, L Prausnitz, JM TI Thermodynamics of fluid mixtures near to and far from the critical region SO AICHE JOURNAL LA English DT Article ID VAPOR-LIQUID-EQUILIBRIUM; CARBON-DIOXIDE; RENORMALIZATION-GROUP; NORMAL-BUTANE; N-BUTANE; STATISTICAL MECHANICS; DIFFERENTIAL APPROACH; LOW-TEMPERATURES; CRITICAL-POINTS; MODE EXPANSION AB A theory for an equation of state for simple fluid mixtures valid both near to and far from critical points is presented. The base equation of state obtained from integral-equation theory using the mean-spherical approximation is used to compute the contribution of short-wavelength fluctuations to the free energy of the fluid mixture. Wilson's phase-space cell approximation, as extended by White, is used to compute the contribution of long-wauelength fluctuations. The resulting theory possesses nonclassic critical exponents similar to those observed experimentally. Far from the critical region, where long-wavelength fluctuations are not important, the theory reduces to that corresponding to the base equation of state. The complete theory is used to represent the thermodynamic properties and phase behavior of binary mixtures of methane, carbon dioxide and n-butane. In the critical region, agreement with experiment is dramatically improved upon, adding to the base equation of state corrections from long-wavelength fluctuations. C1 Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Prausnitz, JM (reprint author), Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. RI Lue, Leo/E-7846-2011 OI Lue, Leo/0000-0002-4826-5337 NR 71 TC 45 Z9 45 U1 1 U2 4 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0001-1541 J9 AICHE J JI AICHE J. PD JUN PY 1998 VL 44 IS 6 BP 1455 EP 1466 DI 10.1002/aic.690440622 PG 12 WC Engineering, Chemical SC Engineering GA ZT298 UT WOS:000074070500021 ER PT J AU Dresden, M AF Dresden, M TI The Klopsteg Memorial Lecture: Fundamentality and numerical scales - Diversity and the structure of physics SO AMERICAN JOURNAL OF PHYSICS LA English DT Article C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Dresden, M (reprint author), Stanford Linear Accelerator Ctr, SLAC Bin 61,POB 4349, Stanford, CA 94309 USA. NR 2 TC 7 Z9 7 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0002-9505 J9 AM J PHYS JI Am. J. Phys. PD JUN PY 1998 VL 66 IS 6 BP 468 EP 482 DI 10.1119/1.18827 PG 15 WC Education, Scientific Disciplines; Physics, Multidisciplinary SC Education & Educational Research; Physics GA ZR866 UT WOS:000074022600003 ER PT J AU Bunimovich, LA Rehacek, J AF Bunimovich, LA Rehacek, J TI On the ergodicity of many-dimensional focusing billiards SO ANNALES DE L INSTITUT HENRI POINCARE-PHYSIQUE THEORIQUE LA English DT Article DE chaos; ergodic billiards; focusing billiards; hyperbolicity ID NOWHERE DISPERSING BILLIARDS; BERNOULLI; SYSTEMS AB The affirmative answer is given to the long standing question whether there exist nowhere dispersing ergodic billiards in dimensions greater than two. To do this we construct a class of n-dimensional domains, n greater than or equal to 3, generating ergodic billiards (that are also Bernoulli systems). (C) Elsevier, Paris. C1 Georgia Inst Technol, Sch Math, SE Appl Anal Ctr, Atlanta, GA 30332 USA. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. RP Bunimovich, LA (reprint author), Georgia Inst Technol, Sch Math, SE Appl Anal Ctr, Atlanta, GA 30332 USA. NR 28 TC 12 Z9 12 U1 0 U2 0 PU GAUTHIER-VILLARS/EDITIONS ELSEVIER PI PARIS PA 23 RUE LINOIS, 75015 PARIS, FRANCE SN 0246-0211 J9 ANN I H POINCARE-PHY JI Ann. Inst. Henri Poincare-Phys. Theor. PD JUN PY 1998 VL 68 IS 4 BP 421 EP 448 PG 28 WC Physics, Multidisciplinary SC Physics GA ZV117 UT WOS:000074271100003 ER PT J AU Vinuesa, P Rademaker, JLW de Bruijn, FJ Werner, D AF Vinuesa, P Rademaker, JLW de Bruijn, FJ Werner, D TI Genotypic characterization of Bradyrhizobium strains nodulating endemic woody legumes of the Canary Islands by PCR-restriction fragment length polymorphism analysis of genes encoding 16S rRNA (16S rDNA) and 16S-23S rDNA intergenic spacers, repetitive extragenic palindromic PCR genomic fingerprinting, and partial 16S rDNA sequencing SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID POLYMERASE CHAIN-REACTION; RIBOSOMAL-RNA GENES; CHAMAECYTISUS-PROLIFERUS; RHIZOBIUM-LEGUMINOSARUM; ROOT-NODULES; DIVERSITY; TAGASASTE; IDENTIFICATION; PALMENSIS; PHYLOGENY AB We present a phylogenetic analysis of nine strains of symbiotic nitrogen-fixing bacteria. isolated from nodules of tagasaste (Chamaecytisus proliferus) and other endemic woody legumes of the Canary Islands, Spain. These and several reference strains mere characterized genotypically at different levels of taxonomic resolution by computer-assisted analysis of 16S ribosomal DNA (rDNA) PCR-restriction fragment length polymorphisms (PCR-RFLPs), 165-23S rDNA intergenic spacer (IGS) RFLPs, and repetitive extragenic palindromic PCR (rep-PCR) genomic fingerprints with BOX, ERIC, and REP primers. Cluster analysis of 16S rDNA restriction patterns with four tetrameric endonucleases grouped the Canarian isolates with the two reference strains, Bradyrhizabium japonicum USDA 110spc4 and Bradyrhizobium sp. strain (Centrosema) CIAT 3101, resolving three genotypes within these bradyrhizobia. In the analysis of IGS RFLPs with three enzymes, six groups were found, whereas rep-PCR fingerprinting revealed an even greater genotypic diversity, with only two of the Canarian strains having similar fingerprints. Furthermore, we show that IGS RFLPs and even very dissimilar rep-PCR fingerprints can be clustered into phylogenetically sound groupings by combining them with 16S rDNA RFLPs in computer-assisted cluster analysis of electrophoretic patterns. The DNA sequence analysis of a highly variable 264-bp segment of the 16S rRNA genes of these strains was found to be consistent with the fingerprint-based classification. Three different DNA sequences were obtained, one of which was not previously described, and all belonged to the B. japoaicum/Rhodopseudomonas rDNA cluster. Nodulation assays revealed that none of the Canarian isolates nodulated Glycine max or Leucaena leucocephala, but all nodulated Acacia pendula, C. proliferus, Macroptilium atropurpureum, and Vigna unguiculata. C1 Univ Marburg, Fachbereich Biol, Fachgebiet Angew Bot & Zellbiol, D-35032 Marburg, Germany. Michigan State Univ, DOE Plant Res Lab, E Lansing, MI 48824 USA. Michigan State Univ, NSF Ctr Microbial Ecol, E Lansing, MI 48824 USA. Michigan State Univ, Dept Microbiol, E Lansing, MI 48824 USA. RP Vinuesa, P (reprint author), Univ Marburg, Fachbereich Biol, Fachgebiet Angew Bot & Zellbiol, Karl Frisch Str, D-35032 Marburg, Germany. EM vinuesa@mailerr.uni-marburg.de NR 52 TC 170 Z9 179 U1 0 U2 13 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 USA SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD JUN PY 1998 VL 64 IS 6 BP 2096 EP 2104 PG 9 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA ZQ805 UT WOS:000073904800017 PM 9603820 ER PT J AU Wasserman, E Felmy, AR AF Wasserman, E Felmy, AR TI Computation of the electrical double layer properties of semipermeable membranes in multicomponent electrolytes SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID ELECTROPHORETIC MOBILITY; BACTERIAL ADHESION; ADSORPTION; SURFACES; CHARGE; WALL AB A methodology is presented for calculating of the surface potential, Donnan potential, and ion concentration profiles for semipermeable microbial membranes that is valid for an arbitrary electrolyte composition. This model for surface potential, Donnan potential, and charge density was applied to recently reported experimental data for gram-positive bacteria, including Bacillus brevis, Rhodococcus opacus, Rhodococcus erythropolis, and Corynebacterium species. These calculations show that previously unconsidered trace amounts of divalent and trivalent cations at very low concentrations (10(-6) M) can have significant effects on the calculated surface and Donnan potentials, at ionic strengths of I less than or equal to 0.01 M, and that these effects need to be considered in accurate modeling of microbial surface, In addition, the calculated ion concentration profiles show that owing to the relatively high surface charges that can develop in microbial membranes, electrostatic effects fan act to significantly concentrate divalent (factors of 5 x 10(3)) and trivalent (factors of 2 x 10(4)) cations within the bacterial cell wall. Comparison of the calculated concentration factors with those derived from experiments shows that a significant fraction of the uptake of metal by bacteria can be explained by the proposed electrostatic model. C1 Pacific NW Natl Lab, WR Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Wasserman, E (reprint author), Pacific NW Natl Lab, WR Wiley Environm Mol Sci Lab, MS KS-96,POB 999, Richland, WA 99352 USA. NR 21 TC 23 Z9 23 U1 0 U2 1 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 USA SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD JUN PY 1998 VL 64 IS 6 BP 2295 EP 2300 PG 6 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA ZQ805 UT WOS:000073904800052 ER PT J AU Armstrong, SC Sturchio, NC Hendry, MJ AF Armstrong, SC Sturchio, NC Hendry, MJ TI Strontium isotopic evidence on the chemical evolution of pore waters in the Milk River aquifer, Alberta, Canada SO APPLIED GEOCHEMISTRY LA English DT Article ID WESTERN CANADA; MASS-TRANSFER; GROUNDWATER; ORIGIN; BASIN; GEOCHEMISTRY; SYSTEMATICS; RADIOCARBON; DIAGENESIS; SR AB Strontium isotope ratios were measured on 13 rock, 18 leachate and 28 pore-water samples from the Milk River aquifer, the confining argillaceous formations, and the glacial till mantling the recharge area. Strontium isotope ratios (Sr-87/Sr-86) of pore waters from the aquifer, confining units, and the glacial till ranged from 0.7069 to 0.7082. The 87Sr/86Sr ratios in aquifer pore waters decrease with increasing distance from the aquifer recharge area, and this is interpreted to be the result of mixing and water-rock interaction within the aquifer. The solute composition of the recharging groundwater is modified by the local lithology, causing distinct geochemical patterns along different flow paths within the aquifer. Whole-rock Sr-87/Sr-86 ratios indicate that the shales and till are generally more radiogenic than the aquifer sandstone. The authigenic carbonate cements and rock-forming minerals comprising the major lithologic units had little apparent influence on the pore-water Sr chemistry. Carbonate cement leachates from the till and the aquifer sandstone are more radiogenic than those from the confining shale formations. Feldspar separates from the aquifer sandstone have relatively radiogenic Sr isotope ratios, whereas bentonites from the Milk River and Colorado Shale Formations have whole-rock and leachate Sr isotope ratios that are relatively unradiogenic. Ratios of most Milk River aquifer pore waters are lower than those of any leachates or whole rocks analyzed, except the bentonites. The Sr-87/Sr-86 ratios of exchangeable Sr in the bentonites are similar to ratios found in the more evolved pore waters. Simple rock-water interaction models calculated for the whole-rock, leachate, and exchangeable-ion/pore-water pairs indicate that ion exchange with bentonite clays within the Milk River and Colorado Shale Formations appears to influence the isotopic evolution of the pore-water Sr in each of these units. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. Univ Saskatchewan, Dept Geol Sci, Saskatoon, SK S7N 5E2, Canada. RP Armstrong, SC (reprint author), Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. NR 41 TC 27 Z9 30 U1 1 U2 13 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0883-2927 J9 APPL GEOCHEM JI Appl. Geochem. PD JUN PY 1998 VL 13 IS 4 BP 463 EP 475 DI 10.1016/S0883-2927(97)00080-2 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA ZX594 UT WOS:000074533900005 ER PT J AU Lee, SF Gildemeister, JM Holmes, W Lee, AT Richards, PL AF Lee, SF Gildemeister, JM Holmes, W Lee, AT Richards, PL TI Voltage-biased superconducting transition-edge bolometer with strong electrothermal feedback operated at 370 mK SO APPLIED OPTICS LA English DT Article ID NOISE AB We present an experimental study of a composite voltage-biased superconducting bolometer (VSB). The tested VSB consists of a Ti-film superconducting thermometer (T-c similar to 375 mK) on a Si substrate suspended by NbTi superconducting leads. A resistor attached to the substrate provides calibrated heat input into the bolometer. The current through the bolometer is measured with a superconducting quantum interference device ammeter. Strong negative electrothermal feedback fixes the bolometer temperature at T, and reduces the measured response time from 2.6 s to 13 ms. As predicted, the measured current responsivity of the bolometer is equal to the inverse of the bias voltage. A noise equivalent power of 5 x 10(-17) W/root Hz was measured for a thermal conductance G similar to 4.7 x 10(-10) W/K, which is consistent with the expected thermal noise. Excess noise was observed for bias conditions for which the electrothermal feedback strength was close to maximum. (C) 1998 Optical Society of America. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. Ctr Particle Astrophys, Berkeley, CA USA. RP Lee, SF (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Dept Phys, Berkeley, CA 94720 USA. NR 12 TC 56 Z9 56 U1 1 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD JUN 1 PY 1998 VL 37 IS 16 BP 3391 EP 3397 DI 10.1364/AO.37.003391 PG 7 WC Optics SC Optics GA ZQ398 UT WOS:000073857200002 PM 18273298 ER PT J AU Colston, BW Everett, MJ Da Silva, LB Otis, LL Stroeve, P Nathel, H AF Colston, BW Everett, MJ Da Silva, LB Otis, LL Stroeve, P Nathel, H TI Imaging of hard- and soft-tissue structure in the oral cavity by optical coherence tomography SO APPLIED OPTICS LA English DT Article ID PERIODONTAL PROBE; SCATTERING; MICROSCOPY AB We have developed a prototype optical coherence tomography (OCT) system for the imaging of hard and soft tissue in the oral cavity. High-resolution images of in vitro porcine periodontal tissues have been obtained with this system. The images clearly show the enamel-cementum and the gingiva-tooth interfaces, indicating OCT is a potentially useful technique for diagnosis of periodontal diseases. To our knowledge, this is the first application of OCT for imaging biologic hard tissue. (C) 1998 Optical Society of America. C1 Univ Calif Lawrence Livermore Natl Lab, Hlth Care Initiat, Livermore, CA 94550 USA. Univ Connecticut, Ctr Hlth, Farmington, CT USA. Univ Calif Davis, Dept Chem Engn & Mat Sci, Davis, CA 95616 USA. RP Colston, BW (reprint author), Univ Calif Lawrence Livermore Natl Lab, Hlth Care Initiat, 7000 E Ave L-399, Livermore, CA 94550 USA. NR 16 TC 146 Z9 151 U1 0 U2 8 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD JUN 1 PY 1998 VL 37 IS 16 BP 3582 EP 3585 PG 4 WC Optics SC Optics GA ZQ398 UT WOS:000073857200031 PM 18273327 ER PT J AU Mourant, JR Freyer, JP Hielscher, AH Eick, AA Shen, D Johnson, TM AF Mourant, JR Freyer, JP Hielscher, AH Eick, AA Shen, D Johnson, TM TI Mechanisms of light scattering from biological cells relevant to noninvasive optical-tissue diagnostics SO APPLIED OPTICS LA English DT Article ID REFRACTIVE-INDEX; FIBROBLASTS AB We have studied the optical properties of mammalian cell suspensions to provide a mechanistic basis for interpreting the optical properties of tissues in vivo. Measurements of the wavelength dependence of the reduced scattering coefficient and measurements of the phase function demonstrated that there is a distribution of scatterer sizes. The volumes of the scatterers are equivalent to those of spheres with diameters in the range between similar to 0.4 and 2.0 mu m. Measurements of isolated organelles indicate that mitochondria and other similarly sized organelles are responsible for scattering at large angles, whereas nuclei are responsible for small-angle scattering. Therefore optical diagnostics are expected to be sensitive to organelle morphology but not directly to the size and shape of the cells. (C) 1998 Optical Society of America. C1 Univ Calif Los Alamos Natl Lab, Biosci & Biotechnol Grp, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Life Sci, Mol & Cell Biol Grp, Los Alamos, NM 87545 USA. RP Mourant, JR (reprint author), Univ Calif Los Alamos Natl Lab, Biosci & Biotechnol Grp, Chem Sci & Technol Div, MS E535, Los Alamos, NM 87545 USA. NR 31 TC 446 Z9 452 U1 3 U2 40 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD JUN 1 PY 1998 VL 37 IS 16 BP 3586 EP 3593 DI 10.1364/AO.37.003586 PG 8 WC Optics SC Optics GA ZQ398 UT WOS:000073857200032 PM 18273328 ER PT J AU Larsson, J Heimann, PA Lindenberg, AM Schuck, PJ Bucksbaum, PH Lee, RW Padmore, HA Wark, JS Falcone, RW AF Larsson, J Heimann, PA Lindenberg, AM Schuck, PJ Bucksbaum, PH Lee, RW Padmore, HA Wark, JS Falcone, RW TI Ultrafast structural changes measured by time-resolved X-ray diffraction SO APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING LA English DT Article ID INDUCED PHASE-TRANSITION; LATTICE INSTABILITY; LASER-PULSES; SILICON; INSB; GAAS; SI; CRYSTAL; DISORDER; FILMS AB High-intensity X-ray pulses from third-generation synchrotron sources make it possible to study the temporal dynamics of rapidly evolving materials. We report a study of rapid and reversible disordering of the structure of an InSb crystal induced by an ultrashort laser pulse. A novel crosscorrelation detection technique is described, which allowed us to observe rapid changes in X-ray diffraction that occur on a time-scale of less than 2 ps. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Accelerator & Fus Res, Berkeley, CA 94720 USA. Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USA. Univ Michigan, Ctr Ultrafast Opt Sci, Ann Arbor, MI 48109 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Univ Oxford, Dept Phys, Clarendon Lab, Oxford OX1 3PU, England. Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Beam Phys, Accelerator & Fus Res Div, Berkeley, CA 94720 USA. RP Falcone, RW (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. EM jorgen@physics.berkeley.edu NR 38 TC 96 Z9 98 U1 0 U2 9 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0947-8396 J9 APPL PHYS A-MATER JI Appl. Phys. A-Mater. Sci. Process. PD JUN PY 1998 VL 66 IS 6 BP 587 EP 591 DI 10.1007/s003390050719 PG 5 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA ZR229 UT WOS:000073953200001 ER PT J AU Theis, CD Yeh, J Schlom, DG Hawley, ME Brown, GW Jiang, JC Pan, XQ AF Theis, CD Yeh, J Schlom, DG Hawley, ME Brown, GW Jiang, JC Pan, XQ TI Adsorption-controlled growth of Bi4Ti3O12 by reactive MBE SO APPLIED PHYSICS LETTERS LA English DT Article ID FILMS; SURFACE AB Adsorption-controlled conditions have been identified and utilized to grow epitaxial bismuth titanate thin films by reactive molecular beam epitaxy. Growth of stoichiometric, phase pure, c-axis oriented, epitaxial films is achieved by supplying a large overabundance of bismuth and ozone continuously to the surface of the depositing film. Titanium is supplied to the film in the form of shuttered bursts each containing a three monolayer dose of titanium to grow one formula unit of Bi3Ti3O12. It is seen from measured film thickness, Rutherford backscattering spectrometry composition measurements, monitoring of reflection high-energy electron diffraction half-order intensity oscillations during growth, and in situ flux measurements using atomic absorption spectroscopy that at suitable temperature and ozone background pressure, the titanium sticking coefficient approaches one and the excess bismuth desorbs from the surface. Film growth proceeds by the formation of mounds whose step heights are predominantly integral multiples of a half-unit cell. (C) 1998 American Institute of Physics. C1 Penn State Univ, Dept Mat Sci & Engn, University Pk, PA 16802 USA. Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. Univ Michigan, Dept Mat Sci & Engn, Ann Arbor, MI 48109 USA. RP Theis, CD (reprint author), Penn State Univ, Dept Mat Sci & Engn, University Pk, PA 16802 USA. RI Schlom, Darrell/J-2412-2013 OI Schlom, Darrell/0000-0003-2493-6113 NR 18 TC 51 Z9 52 U1 0 U2 14 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 1 PY 1998 VL 72 IS 22 BP 2817 EP 2819 DI 10.1063/1.121468 PG 3 WC Physics, Applied SC Physics GA 108PB UT WOS:000075273700014 ER PT J AU Felcher, GP Lohstroh, W Fritzsche, H Munzenberg, M Maletta, H Felsch, W AF Felcher, GP Lohstroh, W Fritzsche, H Munzenberg, M Maletta, H Felsch, W TI Imprinting magnetic structures SO APPLIED PHYSICS LETTERS LA English DT Article ID SUPERLATTICES AB We created helical magnetic structures by depositing in sequence layers of lanthanum and iron (each 30 Angstrom thick) on a substrate rotating in a fixed field of a few Oe. The magnetic field was sufficient to define the magnetization of each layer during growth without disturbing the magnetization of the layers already formed. As a result, the imprinted helical magnetic structure had a chirality given by the direction of rotation of the substrate; the pitch was given by;the speed of rotation and the rate of deposition. This finding indicates that it is possible to engineer mesoscopic magnetic structures. (C) 1998 American Institute of Physics. C1 Univ Gottingen, Inst Phys 1, D-37073 Gottingen, Germany. RP Felcher, GP (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Munzenberg, Markus/B-1251-2010; OI Munzenberg, Markus/0000-0002-1332-5678; Fritzsche, Helmut/0000-0001-5288-8302 NR 12 TC 13 Z9 13 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 1 PY 1998 VL 72 IS 22 BP 2894 EP 2896 DI 10.1063/1.121451 PG 3 WC Physics, Applied SC Physics GA 108PB UT WOS:000075273700040 ER PT J AU Deis, TA Lelovic, M Eror, NG Balachandran, U AF Deis, TA Lelovic, M Eror, NG Balachandran, U TI Effect of Ag doping on structure and critical temperature of Bi2Sr2CaCu2O8+delta superconductors SO APPLIED SUPERCONDUCTIVITY LA English DT Article ID CRITICAL-CURRENT DENSITY; OXYGEN STOICHIOMETRY; STRAIN TOLERANCE; THIN-LAYER; SILVER; TAPES; PHASE; DIFFUSION; SYSTEM; BI1.8PB0.4SR2.0CA2.2CU3.0OY AB The effects of Ag substitution for Bi, Sr and Cu on the c-axis lattice parameter and critical temperature (T-c) were determined for the Bi2-xSr2-yCaCu2-zO8+delta(BSCCO-2212) superconducting phase. Two distinct regimes of behavior were observed: fast cooling represented the regime where the uptake of excess oxygen was the controlling factor and slow cooling represented the regime where the cation content was the controlling factor on the structure and properties, Samples showed higher T-c values and longer c-axes with increased cooling rate. A linear increase in T-c with increase in c-axis length was observed for the faster-cooled samples. For the slow-cooled samples, increased c-axis length was observed when Ag was substituted for Bi and Sr, whereas substituting Ag for Cu caused no change in c-axis length. In addition, any deviation from the ideal 2212 stoichiometry was shown to reduce the T-c values of samples that were slowly cooled and fully oxygenated. Preliminary results obtained by high-resolution transmission electron microscopy coupled with electron energy loss spectroscopy indicated that relatively small amounts of Ag (approximate to 1 at.%) can occupy Bi sites and a larger amount(approximate to 10 at.%) of Ae can substitute for Cu. (C) 1998 Published by Elsevier Science Ltd. All rights reserved. C1 Univ Pittsburgh, Dept Mat Sci & Engn, Pittsburgh, PA 15261 USA. Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. RP Eror, NG (reprint author), Univ Pittsburgh, Dept Mat Sci & Engn, Pittsburgh, PA 15261 USA. NR 34 TC 5 Z9 5 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0964-1807 J9 APPL SUPERCOND JI Appl. Supercond. PD JUN PY 1998 VL 6 IS 6 BP 279 EP 284 DI 10.1016/S0964-1807(98)00045-3 PG 6 WC Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 151NZ UT WOS:000077728100004 ER PT J AU Tilinin, IS Van Hove, MA Salmeron, M AF Tilinin, IS Van Hove, MA Salmeron, M TI Tip-surface transfer of adatoms in AFM/STM: effect of quantum oscillations SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Symposium on Atomically Controlled Surfaces and Interfaces (ACSI 4) CY OCT 27-30, 1997 CL TOKYO, JAPAN SP Minist Educ Sci Sports & Culture, Japan DE adatoms; atom-solid interactions; quantum effects; chemisorption; atomic force microscopy; scanning tunneling microscopy; hydrogen ID SCANNING TUNNELING MICROSCOPE; FIELD; ATOM; MANIPULATION; ADSORPTION; DIFFUSION; METALS; SWITCH; SYSTEM; SCALE AB An adiabatic theory of spontaneous adatom transfer between a surface and an AFM/STM tip has been developed under the assumption that the dwell time of the adsorbate at the adsorption site is small compared to the phonon and electron-hole relaxation times. The adsorbate is assumed to be tunneling across the potential barrier from a ground state at the sample to that at the tip. A simple analytical expression has been obtained for the ground-level energy splitting, which governs the dynamics of the coherent tunneling. The transition rate is shown to depend strongly on the adatom mass, binding energy and separation distance between the adsorption sites. It is found that, at typical AFM/STM tip velocities and separation distances, an adatom may be involved in a process of consecutive transitions from the sample to the tip and vice versa. It is shown that coherent tunneling is a dominant mechanism of adatom transfer at temperatures below 10 K for insulators and semiconductors and below 0.1 K in the case of metals. The total transfer probability as a function of lime may exhibit quantum oscillations whose period is very sensitive to variation of physical parameters. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Tilinin, IS (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. RI Van Hove, Michel/A-9862-2008 OI Van Hove, Michel/0000-0002-8898-6921 NR 22 TC 5 Z9 5 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD JUN PY 1998 VL 130 BP 676 EP 681 DI 10.1016/S0169-4332(98)00137-8 PG 6 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZW404 UT WOS:000074407600117 ER PT J AU Hashimoto, Y Oemler, A Lin, H Tucker, DL AF Hashimoto, Y Oemler, A Lin, H Tucker, DL TI The influence of environment on the star formation rates of galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, clusters, general; galaxies, evolution; galaxies, interactions; galaxies, starburst; galaxies, stellar content; galaxies, structure ID EMISSION-LINE GALAXIES; MORPHOLOGY-DENSITY RELATION; H-ALPHA OBSERVATIONS; REDSHIFT SURVEY; DISTANT CLUSTERS; SPIRAL GALAXIES; RICH CLUSTERS; CLASSIFICATION-SYSTEM; DISK GALAXIES; S0 GALAXIES AB We have used a sample of 15,749 galaxies taken from the Las Campanas Redshift Survey to investigate the effects of environment on the rate of star formation in galaxies. For each galaxy, we derive a measure of the star formation rate (SFR) based on the strength of the [O II] emission line and a measure of galactic structure based on the central concentration of the galaxy's light, which is used to decouple the effect of "morphology-environment" relation from the SFR. Galactic environment is characterized both by the three-space local density of galaxies and by membership in groups and clusters. The size and homogeneity of this data set allows us to sample, for the first time, the entire range of galactic environments, from the lowest density voids to the richest clusters, in a uniform manner. Thus, we could expand our research from the conventional cluster versus field comparison to a new "general" environmental investigation by decoupling the local galaxy density from the membership in associations. This decoupling is crucial for constraining the physical processes responsible for the observed environmental dependencies of star formation. On the other hand, the use of an automatic measure of galactic structure (concentration index) rather than Hubble type, which is a subjective and star formation-contaminated estimate of galactic morphology, allows us to separate cleanly the morphological component from the SFR-environment relationship. We find that, when a cluster/field comparison is made, cluster galaxies exhibit reduced star formation for the same concentration index. This result supports several previous studies based on Hubble type reporting similar suppression of star formation among cluster galaxies for the same Hubble type. We did not find any qualitatively different responses to environments between early-and late-type spirals, which were also previously reported. On the other hand, a further division of clusters by "richness" reveals a new possible excitation of starbursts in groups and poor clusters. Meanwhile, a more general environmental investigation shows that the star formation rate of galaxies with a given concentration index is sensitive to local galaxy density and shows a continuous correlation with the local density, in such a way that galaxies show higher levels of star formation in lower density environments. Interestingly, this trend is also observed both inside and outside of clusters, implying that physical processes responsible for this correlation might not operate intrinsically in the cluster environment. Furthermore, a more complex facet of the dependence of SFR on local density is also revealed; galaxies with differing levels of star formation appear to respond differently to the local density. Low levels of star formation, corresponding to those expected in normal members of the Hubble sequence, are more sensitive to environment inside than outside of clusters. In contrast, high levels of star formation, identified as "starbursts," are at least as sensitive to local density in the field as in clusters. We conclude that at least two separate processes are responsible for the environmental sensitivity of the SFR and tentatively identify gas removal processes as responsible for the variation with density of the SFR of normal galaxies and galaxy-galaxy interactions as responsible for the prevalence of starbursts in intermediate density environments. C1 Carnegie Observ, Pasadena, CA 91101 USA. Yale Univ, Dept Astron, New Haven, CT 06520 USA. Univ Toronto, Dept Astron, Toronto, ON M5S 3H8, Canada. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Hashimoto, Y (reprint author), Carnegie Observ, 813 Santa Barbara St, Pasadena, CA 91101 USA. NR 53 TC 166 Z9 167 U1 1 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 1 PY 1998 VL 499 IS 2 BP 589 EP 599 DI 10.1086/305657 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZU199 UT WOS:000074172200007 ER PT J AU Marshall, FE Gotthelf, EV Zhang, W Middleditch, J Wang, QD AF Marshall, FE Gotthelf, EV Zhang, W Middleditch, J Wang, QD TI Discovery of an ultrafast X-ray pulsar in the supernova remnant N157B SO ASTROPHYSICAL JOURNAL LA English DT Article DE pulsars, general; pulsars, individual (PSR J0537-6910); supernova remnants X-rays, general AB We present the serendipitous discovery of 16 ms pulsed X-ray emission from the Crab-like supernova remnant N157B in the Large Magellanic Cloud. This is the fastest spinning pulsar associated with a supernova remnant (SNR). Observations with the Rossi X-Ray Timing Explorer (RXTE), centered on the field containing SN 1987A, reveal an X-ray pulsar with a narrow pulse profile. The archival Advanced Satellite for Cosmology and Astrophysics (ASCA) X-ray data confirm this detection and locate the pulsar within 1' of the supernova remnant N157B, 14' from SN 1987A. The pulsar shows evidence of glitch(es)between the 3.5 yr separating the RXTE and ASCA observations; the mean linear spin-down rate is P = 5.126 x 10(-14) s s(-1). The background-subtracted, pulsed emission is similar to other Crab-like pulsars with a power law of photon index similar to 1.6. The characteristic spin-down age (similar to 5000 yr) is consistent with;he previous age estimate of the SNR. The inferred B-field for a rotationally powered pulsar is similar to 1 x 10(12) G. Our result confirms the Crab-like nature of N157B; the pulsar is likely associated with a compact X-ray source revealed by ROSAT HRI observations. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Northwestern Univ, Dearborn Observ, Evanston, IL 60208 USA. RP Marshall, FE (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 17 TC 109 Z9 109 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 1 PY 1998 VL 499 IS 2 BP L179 EP L182 DI 10.1086/311381 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZU234 UT WOS:000074175800015 ER PT J AU Minniti, D Vandehei, T Cook, KH Griest, K Alcock, C AF Minniti, D Vandehei, T Cook, KH Griest, K Alcock, C TI Detection of lithium in a main-sequence bulge star using Keck I as a 15 meter diameter telescope SO ASTROPHYSICAL JOURNAL LA English DT Article DE Galaxy, stellar content; stars, abundances; stars, Population II ID MICROLENSING EVENT; HIGH-RESOLUTION; GALACTIC BULGE; OPEN CLUSTERS; ABUNDANCE; METALLICITY; EVOLUTION; DWARFS; DISK AB The bulge contains the most chemically evolved old stellar population in the Milky Way. Thanks to microlensing, it is now possible to obtain high-resolution echelle spectra of bulge stars near the main-sequence turnoff and study the abundance of elements that are affected by stellar evolution, such as lithium. We have observed with the HIRES spectrograph on the Keck I 10 m telescope the source star of the MACHO microlensing event 97 BLG 45, while it was magnified by similar to 1 mag. Here we report the detection of the Li I line at 6707.8 Angstrom in the echelle spectrum of this star and measure the bulge lithium abundance for the first time: A(Li) = 2.25 +/- 0.25. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif San Diego, Dept Phys, San Diego, CA 92093 USA. RP Minniti, D (reprint author), Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. EM dminniti@llnl.gov; vandehei@astrophys.ucsd.edu; kcook@llnl.gov; griest@astrophys.ucsd.edu; alcock@llnl.gov NR 25 TC 27 Z9 27 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 JUN 1 PY 1998 VL 499 IS 2 BP L175 EP L178 DI 10.1086/311360 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZU234 UT WOS:000074175800014 ER PT J AU Owen, JM Villumsen, JV Shapiro, PR Martel, H AF Owen, JM Villumsen, JV Shapiro, PR Martel, H TI Adaptive smoothed particle hydrodynamics: Methodology. II. SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE cosmology, theory; hydrodynamics; large-scale structure of universe; methods, numerical ID N-BODY SIMULATIONS; GALAXY FORMATION; GAS-DYNAMICS; STARS; FRAGMENTATION; CLOUDS; CODE; SPH AB Further development and additional details and tests of adaptive smoothed particle hydrodynamics (ASPH), the new version of smoothed particle hydrodynamics (SPH) described in the first paper in this series (Shapiro et al.), are presented. The ASPH method replaces the isotropic smoothing algorithm of standard SPH, in which interpolation is performed with spherical kernels of radius given by a scalar smoothing length, with anisotropic smoothing involving ellipsoidal kernels and tensor smoothing lengths. In standard SPH, the smoothing length for each particle represents the spatial resolution scale in the vicinity of that particle and is typically allowed to vary in space and time so as to reflect the local value of the mean interparticle spacing. This isotropic approach is not optimal, however, in the presence of strongly anisotropic volume changes such as occur naturally in a wide range of astrophysical flows, including gravitational collapse, cosmological structure formation, cloud-cloud collisions, and radiative shocks. In such cases, the local mean interparticle spacing varies not only in time and space but also in direction as well. This problem is remedied in ASPH, where each axis of the ellipsoidal smoothing kernel for a given particle is adjusted so as to reflect the different mean interparticle spacings along different directions in the vicinity of that particle. By deforming and rotating these ellipsoidal kernels so as to follow the anisotropy of volume changes local to each particle, ASPH adapts its spatial resolution scale in time, space, and direction. This significantly improves the spatial resolving power of the method over that of standard SPH at fixed particle number per simulation. This paper presents an alternative formulation of the ASPH algorithm for evolving anisotropic smoothing kernels, in which the geometric approach of the first paper in this series, based upon the Lagrangian deformation of ellipsoidal fluid elements surrounding each particle, is replaced by an approach involving a local transformation of coordinates to those in which the underlying anisotropic volume changes appear to be isotropic. Using this formulation the ASPH method is presented in two and three dimensions, including a number of details not previously included in the earlier paper, some of which represent either advances or different choices with respect to the ASPH method detailed in the earlier paper. Among the advances included here are an asynchronous time-integration scheme with different time steps for different particles and the generalization of the ASPH method to three dimensions. In the category of different choices, the shock-tracking algorithm described in the earlier paper for locally adapting the artificial viscosity to restrict viscous heating just to particles encountering shocks is not included here. Instead, we adopt a different interpolation kernel for use with the artificial viscosity, which has the effect of spatially localizing effects of the artificial viscosity. This version of the ASPH method in two and three dimensions is then applied to a series of one-, two-, and three-dimensional test problems, and the results are compared to those of standard SPH applied to the same problems. These include the problem of cosmological pancake collapse, the Riemann shock tube, cylindrical and spherical Sedov blast waves, the collision of two strong shocks, and problems involving shearing disks intended to test the angular momentum conservation properties of the method. These results further support the idea that ASPH has significantly better resolving power than standard SPH for a wide range of problems, including that of cosmological structure formation. C1 Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Max Planck Inst Astrophys, D-85740 Garching, Germany. Univ Texas, Dept Astron, Austin, TX 78712 USA. Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. RP Owen, JM (reprint author), Lawrence Livermore Natl Lab, L-16, Livermore, CA 94551 USA. EM mikeowen@llnl.gov; victoria@infinet.com; shapiro@astro.as.utexas.edu; hugo@sagredo.as.utexas.edu NR 34 TC 63 Z9 64 U1 2 U2 11 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 EI 1538-4365 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD JUN PY 1998 VL 116 IS 2 BP 155 EP 209 DI 10.1086/313100 PG 55 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZV145 UT WOS:000074274000001 ER PT J AU Bradley, PA AF Bradley, PA TI Asteroseismological constraints on the structure of the ZZ Ceti stars G117-B15A and R548 SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE stars, evolution; stars, individual (G117-B15A, ZZ Ceti); stars, oscillations; stars, variables, other, ZZ Ceti; white dwarfs ID DA-WHITE-DWARF; THERMONUCLEAR REACTION-RATES; EARTH TELESCOPE OBSERVATIONS; COOLING DEGENERATE DWARF; COMPOSITION GRADIENTS; MAGNETIC-FIELDS; HYDROGEN LAYER; EVOLUTION; MODELS; MASS AB This study compares the theoretical pulsation periods from a new grid of evolutionary DA white dwarf models to the observed periods of the ZZ Ceti white dwarfs G117-B15A and R548 (=ZZ Ceti) in order to constrain their internal structure. Assuming that the similar periods of the two stars is the result of their having nearly identical internal structures, then they must have a hydrogen layer mass of similar to 10(-7)M* or greater. If we follow Clemens's work and identify the period near 215 s as the e = 1, k = 2 mode, then the hydrogen layer mass is close to 10(-4)M*, quite close to the maximum hydrogen layer mass allowed by stellar evolution theory. Based on this analysis, G117-B15A and R548 probably have masses near 0.60 M. and M(H) similar to 10(-4)M*, and R548 is about 0.04 M. less massive than G117-B15A. Alternatively, if 215 s is the k = 1 mode, then the hydrogen layer mass decreases to about 10(-7)M*, but the stellar mass remains near 0.60 M.. In all cases, the helium layer mass is near 10(-2)M*, and the C/O core of both stars is oxygen rich. The existence of the 304 s mode of G117-B15A strongly restricts the allowable core structure. At 0.60 Mo, the core is either 50:50 C/O to 0.75M* or 20:80 C/O to 0.83M*. The fine-structure splitting of R548 is due to slow rotation, and we can duplicate the observed splitting trend and periods if the 213 s mode is k = 2, the model mass is near 0.54 M., and the hydrogen layer mass is near 1.5 x 10(-4)M*. C1 Los Alamos Natl Lab, XTA, Los Alamos, NM 87545 USA. RP Bradley, PA (reprint author), Los Alamos Natl Lab, XTA, MS B220, Los Alamos, NM 87545 USA. NR 49 TC 57 Z9 57 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD JUN PY 1998 VL 116 IS 2 BP 307 EP 319 DI 10.1086/313102 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZV145 UT WOS:000074274000007 ER PT J AU Mashl, RJ Bruinsma, RF AF Mashl, RJ Bruinsma, RF TI Spontaneous-curvature theory of clathrin-coated membranes SO BIOPHYSICAL JOURNAL LA English DT Article ID RECEPTOR-MEDIATED ENDOCYTOSIS; SHAPE TRANSFORMATIONS; ELECTRON-MICROSCOPY; PLASMA-MEMBRANES; FLUID MEMBRANES; BENDING ENERGY; VESICLES; PITS; CELLS; VISUALIZATION AB Clathrin-coated membranes are precursors to coated vesicles in the receptor-mediated endocytic pathway. In this paper we present a physical model for the first steps of the transformation of a clathrin-coated membrane into a coated vesicle. The theory is based on in vitro cytoplasmic acidification experiments of Heuser (J. Cell Biol. 108:401-411) that suggest the transformation proceeds by changes in the chemical environment of the clathrin lattice, wherein the chemical environment determines the amount of intrinsic, or spontaneous, curvature of the network. We show that a necessary step of the transformation, formation of free pentagons in the clathin network, can proceed via dislocation unbinding, driven by changes in the spontaneous curvature. Dislocation unbinding is shown to favor formation of coated vesicles that are quite small compared to those predicted by the current continuum theories, which do not include the topology of the clathrin lattice. C1 Univ Calif Los Angeles, Dept Chem & Biochem, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. RP Mashl, RJ (reprint author), Los Alamos Natl Lab, T-CNLS,MS B258, Los Alamos, NM 87545 USA. EM mashl@lanl.gov NR 54 TC 37 Z9 37 U1 0 U2 5 PU CELL PRESS PI CAMBRIDGE PA 600 TECHNOLOGY SQUARE, 5TH FLOOR, CAMBRIDGE, MA 02139 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD JUN PY 1998 VL 74 IS 6 BP 2862 EP 2875 PG 14 WC Biophysics SC Biophysics GA ZT214 UT WOS:000074061500014 PM 9635740 ER PT J AU Sharp, DH Reinitz, J AF Sharp, DH Reinitz, J TI Prediction of mutant expression patterns using gene circuits SO BIOSYSTEMS LA English DT Article DE gene circuit; simulated annealing; computational biology; gene regulation; theory of metabolism ID SEGMENTATION GENE; FUSHI-TARAZU; DROSOPHILA; HUNCHBACK; MODEL AB Networks of interacting transcription factors, or gene circuits, form an essential part of the metabolic pathways controlling macromolecular synthesis. This paper conveys two new results about gene circuits. We first show how a gene circuit for mutant phenotypes can be constructed from the wild type gene circuit for the same organism. We then present results of computational studies that show that mutant expression patterns can be correctly predicted using gene circuits whose parameters have been determined from wild type data only. Further computational studies demonstrate that this property is insensitive to errors as large as a factor of two in the input data. Together, these results show that gene circuits can be used to identify the regulatory mechanisms governing an entire family of genotypes from a knowledge of the wild type genotype alone. It is argued that this fact forms the basis for a new paradigm in genetics. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. CUNY Mt Sinai Sch Med, Brookdale Ctr Mol Biol, Div Theoret, New York, NY 10029 USA. RP Sharp, DH (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, MS B285, Los Alamos, NM 87545 USA. FU NCRR NIH HHS [R01-RR07801] NR 24 TC 47 Z9 47 U1 0 U2 1 PU ELSEVIER SCI IRELAND LTD PI CLARE PA CUSTOMER RELATIONS MANAGER, BAY 15, SHANNON INDUSTRIAL ESTATE CO, CLARE, IRELAND SN 0303-2647 J9 BIOSYSTEMS JI Biosystems PD JUN-JUL PY 1998 VL 47 IS 1-2 SI SI BP 79 EP 90 DI 10.1016/S0303-2647(98)00014-8 PG 12 WC Biology; Mathematical & Computational Biology SC Life Sciences & Biomedicine - Other Topics; Mathematical & Computational Biology GA 105HF UT WOS:000075066100006 PM 9715752 ER PT J AU Moya, J Garrahan, KG Poston, TM Durell, GS AF Moya, J Garrahan, KG Poston, TM Durell, GS TI Effects of cooking on levels of PCBs in the fillets of winter flounder SO BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY LA English DT Article ID POLYCHLORINATED-BIPHENYLS; BLUEFISH; DDT C1 US EPA, Washington, DC 20460 USA. Pacific NW Lab, Richland, WA 99352 USA. Battelle Ocean Sci, Duxbury, MA 02332 USA. RP Moya, J (reprint author), US EPA, 8623D,401 M St SW, Washington, DC 20460 USA. NR 11 TC 12 Z9 14 U1 0 U2 7 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0007-4861 J9 B ENVIRON CONTAM TOX JI Bull. Environ. Contam. Toxicol. PD JUN PY 1998 VL 60 IS 6 BP 845 EP 851 PG 7 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA ZQ707 UT WOS:000073895000003 PM 9606259 ER PT J AU Nadeau, RM Johnson, LR AF Nadeau, RM Johnson, LR TI Seismological studies at Parkfield VI: Moment release rates and estimates of source parameters for small repeating earthquakes SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID SAN-ANDREAS-FAULT; CENTRAL CALIFORNIA; RECURRENCE MODEL; STRESS DROP; SLIP; ZONE; INVERSION; RUPTURE; CHOLAME; MOTION AB Waveform data from a borehule network of broadband seismographic stations have been used to study microearthquakes along the Parkfield segment of the San Andreas fault (SAF). Analysis of almost 10 years of such data demonstrates that much of the seismicity in this region consists of repeating sequences, quasiperiodic sequences of earthquakes that are essentially identical in terms of waveform, size, and location. Scalar seismic moments have been estimated for 53 of these repeating sequences and combined with equivalent estimates from 8 similar but larger event sequences from the Stone Canyon section of the fault and the main Parkfield sequence. These estimates show that seismic moment is being released as a function of time in a very regular manner. Measurements of the moment release rate, combined with an assumed tectonic loading rate, lead to estimates of the seismic parameters source area, slip, and recurrence interval. Such parameters exhibit a systematic dependence upon source size over a range of 10(10) in seismic moment that can be described by three simple scaling relational-Lips. Several implications of these scaling relationships are explored, including the repeat time of earthquakes, average stress drop, strength of the fault, and heat generated by earthquakes, What emerges from this analysis of moment release rates is a quantitative description of an earthquake process that is controlled by small strong asperities that occupy less than 1% of the fault area. This means that the fault is highly heterogeneous with respect to stress, strength, and heat generation. Such heterogeneity helps to explain many of the apparent contradictions that are encountered in the study of earthquakes, such as why faults appear weak, why significant heat flow is not observed, how significant high frequencies can be generated by large earthquakes, and, how various,geologic features such as pseudotachylytes might form. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Computat Seismol, Berkeley, CA 94720 USA. Univ Calif Berkeley, Berkeley Seismol Lab, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Computat Seismol, Berkeley, CA 94720 USA. NR 78 TC 213 Z9 224 U1 1 U2 15 PU SEISMOLOGICAL SOC AMER PI ALBANY PA 400 EVELYN AVE, SUITE 201, ALBANY, CA 94706-1375 USA SN 0037-1106 EI 1943-3573 J9 B SEISMOL SOC AM JI Bull. Seismol. Soc. Amer. PD JUN PY 1998 VL 88 IS 3 BP 790 EP 814 PG 25 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA ZU965 UT WOS:000074254300013 ER PT J AU Yang, XN Stump, BW Phillips, WS AF Yang, XN Stump, BW Phillips, WS TI Source mechanism of an explosively induced mine collapse SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID UNITED-STATES EARTHQUAKES; MOMENT TENSORS; DEEP-LEVEL; STRESS; SPALL; DISCRIMINATION; SEISMICITY; TREMORS AB Mining explosions and collapses, in addition to earthquakes, may trigger the future Comprehensive Test Ban Treaty (CTBT) monitoring system. Many shallow, spontaneously occurring mine collapses have implosional source mechanisms that might provide a physical basis to discriminate them from explosions. In this study, an explosively induced mine collapse was investigated, The collapse occurred immediately after the support pillars of a 320-m-deep underground mine opening were destroyed by explosives. It had an Lg body-wave magnitude (m(bLg)) of 2.8, We analyzed free-surface ground-motion data (within 1200 m) from the collapse by waveform forward modeling and time-dependent source moment-tenser inversion. The results indicate that the source mechanism of the collapse can be represented by a horizontal opening and closing crack, The time functions of the diagonal source moment-tenser components are similar to that of a spall source accompanying an underground explosion. A unique source characteristic of the induced collapse is that, unlike spontaneous collapses, the induced collapse initiated as a tensile crack. Because of the initially expansive source characteristic, this kind of induced mine collapses may pose some difficulties to the seismic discrimination problem. Despite the similarities between the induced mine collapse and underground explosions, the collapse has a more band-limited source spectrum and seems to be more efficient in shear and surface-wave generation. C1 Los Alamos Natl Lab, Los Alamos, NM 87544 USA. So Methodist Univ, Dept Geol Sci, Dallas, TX 75275 USA. RP Yang, XN (reprint author), Los Alamos Natl Lab, EEE-3,MS C335, Los Alamos, NM 87544 USA. EM xyang@lanl.gov; stump@passion.isem.smu.edu; wsp@lanl.gov NR 35 TC 14 Z9 15 U1 0 U2 0 PU SEISMOLOGICAL SOC AMER PI EL CERRITO PA PLAZA PROFESSIONAL BLDG, SUITE 201, EL CERRITO, CA 94530 USA SN 0037-1106 J9 B SEISMOL SOC AM JI Bull. Seismol. Soc. Amer. PD JUN PY 1998 VL 88 IS 3 BP 843 EP 854 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA ZU965 UT WOS:000074254300016 ER PT J AU Norato, MA Tsouris, C Tavlarides, LL AF Norato, MA Tsouris, C Tavlarides, LL TI Phase inversion studies in liquid-liquid dispersions SO CANADIAN JOURNAL OF CHEMICAL ENGINEERING LA English DT Article DE liquid-liquid dispersions; phase inversion; ambivalence region; hysteresis ID COALESCENCE AB A study of the phase inversion behavior of liquid-liquid dispersions in stirred vessels is performed for liquids of various physical properties at various operating conditions. Physical parameters studied are density (867 to 1180 kg/m(3)), viscosity (0.00096 to 0.00378 Pa s), and interfacial tension (0.0089 to 0.0323 N/m). Ambivalence region plots are presented and compared with results reported in the literature. Experiments are performed to examine the effects of impeller type and impeller-to-tank diameter ratio (D/T) on the ambivalence behavior. Also, phase inversion time experiments are performed to investigate the time required for complete phase inversion under various dynamic conditions. The traditional method of plotting the organic phase volume fraction at phase inversion against the agitation speed at that condition is compared with the method of plotting the initially dispersed phase volume fraction at phase inversion against the agitation speed at that condition. A hysteresis phenomenon is shown in phase inversion from O/W to W/O and W/O to O/W dispersions. Also, it is shown that, depending on the physical properties of the dispersed and continuous phases, phase inversion may occur when the agitation speed is increased or decreased. C1 Syracuse Univ, Dept Chem Engn & Mat Sci, Syracuse, NY 13244 USA. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. RP Tavlarides, LL (reprint author), Syracuse Univ, Dept Chem Engn & Mat Sci, Syracuse, NY 13244 USA. EM rrdewey@syr.edu RI Tsouris, Costas/C-2544-2016 OI Tsouris, Costas/0000-0002-0522-1027 NR 14 TC 30 Z9 33 U1 4 U2 7 PU CANADIAN SOC CHEMICAL ENGINEERING PI OTTAWA PA 130 SLATER ST, STE 550, OTTAWA, ONTARIO K1P 6E2, CANADA SN 0008-4034 J9 CAN J CHEM ENG JI Can. J. Chem. Eng. PD JUN PY 1998 VL 76 IS 3 BP 486 EP 494 PG 9 WC Engineering, Chemical SC Engineering GA 110BQ UT WOS:000075359700018 ER PT J AU Tsouris, C Shin, WT Yiacoumi, S AF Tsouris, C Shin, WT Yiacoumi, S TI Pumping, spraying, and mixing of fluids by electric fields SO CANADIAN JOURNAL OF CHEMICAL ENGINEERING LA English DT Article DE electrostatic spraying; gas-liquid dispersions; liquid-liquid dispersions; microbubbles; microdrops ID CONE-JET MODE; EMULSION-PHASE CONTACTOR; ELECTROSTATIC DISPERSION; NONCONDUCTIVE FLUIDS; CONDUCTIVE FLUIDS; LIQUIDS; CORONA; ELECTRODISPERSION; ELECTROSPRAYS; GENERATION AB The mechanism of electrostatic spraying of insulating fluids, such as air or organic solvents, into relatively conductive fluids, such as water, is investigated in this work. Experiments with air sprayed into water through an electrified capillary showed that the pressure inside the capillary increases, reaches a maximum, and then decreases as the applied voltage is increased. The initial pressure increase is due to the electric stress on the fluid interface, while the decrease is due to the Coulombic electrohydrodynamic flow generated near the end of the capillary. It is shown that electric fields can cause simultaneous pumping, spraying, and mixing of fluids. This phenomenon is demonstrated for air and kerosene in water. C1 Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. Georgia Inst Technol, Sch Civil & Environm Engn, Atlanta, GA 30332 USA. RP Tsouris, C (reprint author), Oak Ridge Natl Lab, Div Chem Technol, POB 2008, Oak Ridge, TN 37831 USA. EM tsourisc@ornl.gov RI Tsouris, Costas/C-2544-2016 OI Tsouris, Costas/0000-0002-0522-1027 NR 47 TC 26 Z9 26 U1 0 U2 3 PU CANADIAN SOC CHEMICAL ENGINEERING PI OTTAWA PA 130 SLATER ST, STE 550, OTTAWA, ONTARIO K1P 6E2, CANADA SN 0008-4034 J9 CAN J CHEM ENG JI Can. J. Chem. Eng. PD JUN PY 1998 VL 76 IS 3 BP 589 EP 599 PG 11 WC Engineering, Chemical SC Engineering GA 110BQ UT WOS:000075359700030 ER PT J AU Finch, RJ Hawthorne, FC Ewing, RC AF Finch, RJ Hawthorne, FC Ewing, RC TI Structural relations among schoepite, metaschoepite and "dehydrated schoepite" SO CANADIAN MINERALOGIST LA English DT Article DE schoepite; metaschoepite; uranyl oxide hydrate; uranium minerals; dehydration; phase transformation ID SPENT NUCLEAR-FUEL; CRYSTAL-STRUCTURE; URANIUM; OXIDATION; MINERALS; OXIDE; CORROSION; PHASE; UO2; TEMPERATURES AB Schoepite, [(UO2)(8)O-2(OH)(12)](H2O)(12), transforms slowly in air at ambient temperature to metaschoepite, UO3. nH(2)O (n congruent to 2), and crystals commonly contain an intergrowth of both minerals. The transformation may be due to the loss of one-sixth of the interlayer H2O groups in schoepite, and a possible structural formula for metaschoepite is [(UO2)(8)O-2(OH)(12)](H2O)(10). The transformation of schoepite (a 14.337, b 16.813, c 14.731 Angstrom, P2(1)ca) to metaschoepite (a 13.99, b 16.72, c 14.73 Angstrom, Pbna) is characterized by a 2% decrease in the a cell dimension, a slight decrease in the b dimension, and little or no change in the c dimension. Unit-cell changes probably reflect the reorganization of H-bonds. Differences in unit-cell volumes induce strain in crystals in which the transformation to metaschoepite is incomplete, and stored strain energy may be sufficient to rapidly drive the transformation of the remaining schoepite to "dehydrated schoepite" [a 6.86, b 4.26, c 10.20 Angstrom, Abcm (?)] when partly altered crystals are exposed to an external stress (e.g., heat, sunlight or mechanical pressure). Metaschoepite is apparently stable in air; canary yellow altered crystals commonly consist of a polycrystalline mixture of "dehydrated schoepite" and metaschoepite. The alteration of schoepite to "dehydrated schoepite" occurs in three steps: (1) loss of all interlayer H2O from schoepite, causing collapse of the layers, (2) atomic rearrangement within the structural sheets to a configuration that may be similar to that of metaschoepite, and (3) further re-arrangement to a defect alpha-UO2(OH)(2)-type sheet. The complete reaction is [(UO2)(8)O-2(OH)(12)](H2O)(12) double right arrow 8 [(UO2)O-0.25(OH)(1.5)] + 12H(2)O. We propose that "dehydrated schoepite" forms an omission solid-solution over the compositional range UO3. 0.75H(2)O to UO3. H2O, represented by the general formula (UO2)O0.25-x(OH)(1.5 +2x) (0 less than or equal to x less than or equal to 0.25). C1 Univ Manitoba, Dept Geol Sci, Winnipeg, MB R3T 2N2, Canada. Univ Michigan, Dept Nucl Engn & Radiol Sci, Ann Arbor, MI 48109 USA. RP Finch, RJ (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Hawthorne, Frank/F-6864-2011; Finch, Robert/D-9553-2013 OI Hawthorne, Frank/0000-0001-6405-9931; Finch, Robert/0000-0001-9342-5574 NR 52 TC 59 Z9 59 U1 0 U2 22 PU MINERALOGICAL ASSOC CANADA PI NEPEAN PA CITYVIEW 78087, NEPEAN, ONTARIO K2G 5W2, CANADA SN 0008-4476 J9 CAN MINERAL JI Can. Mineral. PD JUN PY 1998 VL 36 BP 831 EP 845 PN 3 PG 15 WC Mineralogy SC Mineralogy GA 134WR UT WOS:000076767200015 ER PT J AU Hoover, WG Posch, HA AF Hoover, WG Posch, HA TI Chaos and irreversibility in simple model systems SO CHAOS LA English DT Article ID NONEQUILIBRIUM-MOLECULAR-DYNAMICS; SHEAR VISCOSITY; CONTINUUM-MECHANICS; HAMILTONIAN-SYSTEMS; LYAPUNOV EXPONENTS; LORENTZ GAS; TIME; TRANSPORT; ENTROPY; FLOW AB The multifractal link between chaotic time-reversible mechanics and thermodynamic irreversibility is illustrated for three simple chaotic model systems: the Baker Map, the Galton Board, and many-body color conductivity. By scaling time, or the momenta, or the driving forces, it can be shown that the dissipative nature of the three thermostated model systems has analogs in conservative Hamiltonian and Lagrangian mechanics. Links between the microscopic nonequilibrium Lyapunov spectra and macroscopic thermodynamic dissipation are also pointed out. (C) 1998 American Institute of Physics. C1 Univ Calif Lawrence Livermore Natl Lab, Dept Appl Sci, Livermore, CA 94551 USA. Univ Vienna, Inst Phys Expt, A-1090 Vienna, Austria. RP Hoover, WG (reprint author), Univ Calif Lawrence Livermore Natl Lab, Dept Appl Sci, Livermore, CA 94551 USA. NR 44 TC 17 Z9 17 U1 1 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1054-1500 J9 CHAOS JI Chaos PD JUN PY 1998 VL 8 IS 2 BP 366 EP 373 DI 10.1063/1.166318 PG 8 WC Mathematics, Applied; Physics, Mathematical SC Mathematics; Physics GA ZV158 UT WOS:000074275600007 ER PT J AU Milanovic, L Posch, HA Hoover, WG AF Milanovic, L Posch, HA Hoover, WG TI Lyapunov instability of two-dimensional fluids: Hard dumbbells SO CHAOS LA English DT Article ID CHARACTERISTIC EXPONENTS; SYSTEMS; DYNAMICS; SPECTRUM; LIMIT AB We generalize Benettin's classical algorithm for the computation of the full Lyapunov spectrum to the case of a two-dimensional fluid composed of linear molecules modeled as hard dumbbells. Each dumbbell, two hard disks of diameter a with centers separated by a fixed distance d, may translate and rotate in the plane. We study the mixing between these qualitatively different degrees of freedom and its influence hard elastic collisions. We apply the exact collision rules for the differential offset vectors in tangent space to the computation of the Lyapunov exponents, and of time-averaged offset-vector projections into various subspaces of the phase space. For the case of a homogeneous mass distribution within a dumbbell we find that for small enough dla, depending on the density, the translational part of the Lyapunov spectrum is decoupled from the rotational part and converges to the spectrum of hard disks. (C) 1998 American Institute of Physics. C1 Univ Vienna, Inst Phys Expt, A-1090 Vienna, Austria. Univ Calif Lawrence Livermore Natl Lab, Dept Appl Sci, Livermore, CA 94551 USA. RP Milanovic, L (reprint author), Univ Vienna, Inst Phys Expt, Boltzmanngasse 5, A-1090 Vienna, Austria. NR 32 TC 16 Z9 16 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1054-1500 J9 CHAOS JI Chaos PD JUN PY 1998 VL 8 IS 2 BP 455 EP 461 PG 7 WC Mathematics, Applied; Physics, Mathematical SC Mathematics; Physics GA ZV158 UT WOS:000074275600015 ER PT J AU Hsu, CW Evans, M Stimson, S Ng, CY Heimann, P AF Hsu, CW Evans, M Stimson, S Ng, CY Heimann, P TI High-resolution photoelectron spectroscopy using multibunch synchrotron radiation: rotational-resolved photoelectron bands of O-2(+)(b(4)Sigma(-)(g),upsilon(+)) SO CHEMICAL PHYSICS LA English DT Article ID PULSED-FIELD-IONIZATION; CONFIGURATION-INTERACTION CALCULATIONS; THRESHOLD PHOTOELECTRON; PHOTO-IONIZATION; SHAPE-RESONANCE; RYDBERG STATES; PREDISSOCIATION LIFETIMES; COLLISIONAL ENHANCEMENT; DIATOMIC-MOLECULES; CROSS-SECTIONS AB We report rotational-resolved single-photon threshold photoelectron and pulsed field ionization zero kinetic energy (PFI-ZEKE) photoelectron (PE) spectra of O-2 in the energy range of 18.1-20.2 eV measured using high-resolution monochromatized multibunch undulator synchrotron radiation. The PFI-ZEKE PE bands for O-2(+)(b (4)Sigma(g)(-) v(+) = 0-9) have been simulated using the Buckingham-Orr-Sichel model derived for rotationally resolved single-photon ionization cross-sections. Only the Delta N = - , 0 and +2 (or O, Q and S) rotational branches are observed for these PFI-ZEKE PE bands, indicating that the outgoing electron continuum channels with angular momenta l = 1 and 3 dominate in the threshold ionization transitions O-2(+)(b (4)Sigma(g)(-), v(+) = 0-9, N+) <-- O-2(X (3)Sigma(g)(-), v" = O, N"). The relative rotational branch intensities for O-2(+)(b (4)Sigma(g)(-), v(+) = 4 and 5) are found to be drastically different from those for O-2(+)(b (4)Sigma(g)(-), v(+) = 0-3, 6 and 7). Considering that the energies of O-2(+)(b (4)Sigma(g)(-), v(+) = 4 and 5) are close to the dissociation limit of O+(S-4) + O(P-3) and that the crossing location of the O-2(+)(b (4)Sigma(g)(-)) and d (4)Sigma(g)(+) potential curves is shown to be in the vicinity of O-2(+)(b (4)Sigma(g)(-), v(+) = 4 and 5), we suggest that the latter observation is thee result of predissociative perturbations by the d (4)Sigma(g)(+) state. Within the uncertainties of this experiment, the ionization energies for the formation of O-2(+)(b (4)Sigma(g)(-), v(+) = 0-9, N+ - 1) can be satisfactorily characterized using a Morse potential. The effective lifetimes for high-n Rydberg states converging to O-2(+)(b (4)Sigma(g)(-), v(+) = 0, 2-5) prepared in the present experiment are nearly constant with values in the range of 1.8-2.0 mu s The observation that the effective lifetimes for high-n Rydberg states converging to O-2(+)(b (4)Sigma(g)(-), v(+) = 4 and 5) are significantly longer than the known dissociative lifetimes of the corresponding ionic states is in accordance with the expectation that the couplings between the O-2 ion core and the high-n Rydberg electron involved are negligibly small. (C) 1998 Elsevier Science B,V. All rights reserved. C1 Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames Lab, Ames, IA 50011 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source & Accelerator & Fus Res Div, Berkeley, CA 94720 USA. RP Ng, CY (reprint author), Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA. EM cyng@ameslab.gov NR 61 TC 30 Z9 31 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0104 J9 CHEM PHYS JI Chem. Phys. PD JUN 1 PY 1998 VL 231 IS 2-3 BP 121 EP 143 DI 10.1016/S0301-0104(97)00342-X PG 23 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZT945 UT WOS:000074144200003 ER PT J AU Blank, DA Hemmi, N Suits, AG Lee, YT AF Blank, DA Hemmi, N Suits, AG Lee, YT TI A crossed molecular beam investigation of the reaction Cl+propane -> HCl+C3H7 using VUV synchrotron radiation as a product probe SO CHEMICAL PHYSICS LA English DT Article ID DYNAMICS; DISTRIBUTIONS; HYDROCARBONS; ABSTRACTION; SECTIONS; CHLORINE; ATOMS; HCL; CL AB We have used the crossed molecular beam technique to study the hydrogen atom abstraction from propane by atomic chlorine over a wide range of collision energies. The experiments were carried out using a recently constructed crossed molecular beam apparatus that utilizes tunable VUV synchrotron radiation for product photoionization. We have measured laboratory TOF spectra and angular distributions for E-coll = 8.0, 11.5, and 31.6 kcal/mol. Center-of-mass flux maps were generated from the measured laboratory distributions. The results demonstrate two distinct reaction mechanisms that depend on the impact parameter of the reactive collision. Large impact parameter collisions proceed via a stripping mechanism resulting in forward scattered products with very little momentum change in going from reactant to product. The stripping reactions are most likely dominated by abstraction of secondary hydrogen atoms. Smaller impact parameter collisions lead to direct reactions with an impulsive recoil and are consistent with a preference for a collinear transition state geometry, C-H-Cl. The larger energy along the line of centers in smaller impact parameter collisions most likely makes the effect of a larger barrier to abstraction of primary hydrogen atoms negligible leaving the ratio of primary to secondary hydrogen abstraction to be dictated by simple statistics. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Blank, DA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RI Lee, Yuan-Tseh/F-7914-2012 NR 24 TC 47 Z9 50 U1 0 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0104 J9 CHEM PHYS JI Chem. Phys. PD JUN 1 PY 1998 VL 231 IS 2-3 BP 261 EP 278 DI 10.1016/S0301-0104(98)00021-4 PG 18 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZT945 UT WOS:000074144200014 ER PT J AU Jankowiak, R Ariese, F Hewer, A Luch, A Zamzow, D Hughes, NC Phillips, D Seidel, A Platt, KL Oesch, F Small, GJ AF Jankowiak, R Ariese, F Hewer, A Luch, A Zamzow, D Hughes, NC Phillips, D Seidel, A Platt, KL Oesch, F Small, GJ TI Structure, conformations, and repair of DNA adducts from dibenzo[a,l]pyrene: P-32-postlabeling and fluorescence studies SO CHEMICAL RESEARCH IN TOXICOLOGY LA English DT Article ID TUMOR-INITIATING ACTIVITY; RAT MAMMARY-GLAND; MOUSE SKIN; FJORD-REGION; DIOL-EPOXIDE; CARCINOGEN DIBENZOPYRENE; AROMATIC-HYDROCARBONS; MUTAGENIC SPECIFICITY; COVALENT BINDING; BENZOPYRENE AB The nature of stable DNA adducts derived from the very potent carcinogen dibenzo[alpha,l]pyrene (DB[alpha,l]P) in the presence of rat liver microsomes in vitro and in mouse skin in vivo has been studied using P-32-postlabeling and laser-based fluorescence techniques. Analysis of DB[alpha,l]P-DNA adducts via P-32-postlabeling has been obtained by comparison of the adduct patterns to those obtained from reactions of synthetic (+/-)-anti-, (+)-anti-, (-)-anti-, and (+/-)-syn-DB[alpha,l]P-11,12-diol 13,14-epoxide (DB[alpha,l]PDE) with single nucleotides and calf thymus DNA. anti-DB[alpha,l]PDE-dA adducts derived from the (-)-enantiomer are the major adducts formed in calf thymus DNA and in mouse skin DNA. The ratio of deoxyadenosine to deoxyguanosine modification is approximately 2:1 in mouse skin exposed to DB[alpha,l]P; activation by rat liver microsomes leads to a similar profile of adducts but with two additional spots. The conformations of DB[alpha,l]P adducts in native DNA, as well as the possibility of conformation-dependent repair, have been explored by low-temperature fluorescence spectroscopy. These studies have been performed using polynucleotides and calf thymus DNA reacted in vitro with DB[alpha,l]PDE and native DNA from mouse epidermis exposed to DB[alpha,l]P. The results show that adducts are heterogeneous, possess different structures, and adopt different conformations. External, external but base-stacked and intercalated adduct conformations are observed in calf thymus DNA and in mouse skin DNA samples. Differences in adduct repair rates are also revealed; namely, the analysis of mouse skin DNA samples obtained at 24 and 48 h after exposure to DB[alpha,l]P clearly shows that external adducts are repaired more efficiently than intercalated adducts. These results, taken together with those for B[alpha]P-DNA adducts [Suh et al. (1995) Carcinogenesis 16, 2561-2569], indicate that the repair of DNA damage resulting from PAH diol epoxides is conformation dependent. C1 Iowa State Univ, Ames Lab, USDOE, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Inst Canc Res, Haddow Labs, Sutton SM2 5NG, Surrey, England. Univ Mainz, Inst Toxicol, D-55131 Mainz, Germany. RP Jankowiak, R (reprint author), Iowa State Univ, Ames Lab, USDOE, 706 Gilman Hall, Ames, IA 50011 USA. EM jankowiak@ameslab.gov NR 44 TC 28 Z9 30 U1 0 U2 0 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 JUN PY 1998 VL 11 IS 6 BP 674 EP 685 DI 10.1021/tx970232k PG 12 WC Chemistry, Medicinal; Chemistry, Multidisciplinary; Toxicology SC Pharmacology & Pharmacy; Chemistry; Toxicology GA ZV403 UT WOS:000074301100011 PM 9625736 ER PT J AU Schoonover, JR Strouse, GF AF Schoonover, JR Strouse, GF TI Time-resolved vibrational spectroscopy of electronically excited inorganic complexes in solution SO CHEMICAL REVIEWS LA English DT Review ID RESONANCE RAMAN-SPECTROSCOPY; TRANSITION-METAL COMPLEXES; ACTIVE RHENIUM(I) PHOTOSENSITIZERS; ULTRAFAST INFRARED-SPECTROSCOPY; INTRAMOLECULAR ENERGY-TRANSFER; CHROMOPHORE-QUENCHER COMPLEX; VIBRONIC COUPLING MODEL; BOND-LENGTH CHANGES; SCAN FT-IR; CHARGE-TRANSFER C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Univ Calif Santa Barbara, Dept Chem, Santa Barbara, CA 93106 USA. RP Schoonover, JR (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Mail Stop J586, Los Alamos, NM 87545 USA. EM schoons@lanl.gov; Strouse@chem.ucsb.edu NR 185 TC 100 Z9 100 U1 3 U2 26 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0009-2665 J9 CHEM REV JI Chem. Rev. PD JUN PY 1998 VL 98 IS 4 BP 1335 EP 1355 DI 10.1021/cr950273q PG 21 WC Chemistry, Multidisciplinary SC Chemistry GA ZV899 UT WOS:000074352900004 ER PT J AU Anderson, MT Martin, JE Odinek, JG Newcomer, PP AF Anderson, MT Martin, JE Odinek, JG Newcomer, PP TI Effect of methanol concentration on CTAB micellization and on the formation of surfactant-templated silica (STS) SO CHEMISTRY OF MATERIALS LA English DT Article ID MESOPOROUS MOLECULAR-SIEVES; MCM-41; CATALYST; ORGANIZATION; OXIDATION AB We use Light-scattering techniques to study the effects of methanol concentration on alkaline, cetyltrimethylammonium bromide (CTAB) water:methanol micellar solutions. We use X-ray diffraction, SEM, TEM, Si-29 NMR, and gas sorption measurements to study the structure, microstructure, and porosity of surfactant-templated silica (STS), synthesized by adding tetramethoxysilane (TMOS) to the above micellar solutions. The measured critical micelle concentration (cmc) for CTAB at 25 degrees C in a 0.22 M NaOH (pH 13.2) solvent increases from similar to 1.3 x 10(-3) M for r = 0% to similar to 5.5 x 10(-2) M for r = 60% (where r is the wt % methanol in the mixture) as the concentration of methanol increases. In turn, the long-range order of STS decreases as the methanol concentration increases. Ordered STS forms for 0 less than or equal to r < 60%, where the concentration of CTAB, c, is greater than cmc in the precursor solution; disordered STS (resembling wormlike micelles) forms for 60 less than or equal to r less than or equal to 90%, where c < cmc. For r > 90% transparent, amorphous chemical gels form. The presence of methanol leads to a uniform submicron microstructure as compared to faceted 1-10-mu m particles with pure water. After template removal, apparent BET surface areas for STS can exceed 950 m(2)/g, and the void volume can exceed 0.6 cm(3)/g. Initially, there is a high fraction of uncondensed silica in the as-made product (Q(3)/Q(4), approximate to 2.1), but after calcination a strong, bonded siloxane framework forms (Q(3)/Q(4) approximate to 0.40). C1 Sandia Natl Labs, Encapsulants & Porous Mat Dept, Albuquerque, NM 87185 USA. Sandia Natl Labs, Nanostruct & Adv Mat Chem Dept, Albuquerque, NM 87185 USA. RP Anderson, MT (reprint author), 3M Ctr, Ceram Technol Ctr, Ind & Consumer Sector Res Lab, Bldg 201-4N-01, St Paul, MN 55144 USA. NR 37 TC 65 Z9 65 U1 1 U2 21 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD JUN PY 1998 VL 10 IS 6 BP 1490 EP 1500 DI 10.1021/cm970240m PG 11 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA ZV160 UT WOS:000074275800004 ER PT J AU Christensen, AN Jensen, TR Norby, P Hanson, JC AF Christensen, AN Jensen, TR Norby, P Hanson, JC TI In situ synchrotron x-ray powder diffraction studies of crystallization of microporous aluminophosphates and Me2+-substituted aluminophosphates SO CHEMISTRY OF MATERIALS LA English DT Article ID IN-SITU AB in situ synchrotron X-ray powder diffraction was used to study the crystallization of microporous aluminophosphate and of Mg2+-, Mn2+-, Co2+-, and Zn2+-substituted aluminophosphates. The gels contained the templates 2-(diethylamino)ethanol, di-n-propylamine, triethylamine, and tripropylamine and were heated in quartz glass capillaries at temperatures up to 200 degrees C, The main crystalline reaction products formed were AlPO4 (tridymite type), APO-5 (AFI), APO-11(AEL), MgAPO-5 (AFI), MnAPO-5 (AFI), CoAPO-5 (AFI), ZnAPO-39 (ATN), and ZnAPO-47 (CHA). A kinetic analysis of the crystallization of MnAPO-5 (AFI) and ZnAPO-47 (CHA) was performed using isothermal in situ synchrotron X-ray powder diffraction data. The apparent activation energies for the hydrothermal nucleation of MnAPO-5 (AFI) and ZnAPO-47 (CHA) were 161(6) and 112(3) KJ/mol, respectively. The crystallization of MnAPO-5 could be modeled using a first-order expression giving an apparent activation energy of the crystal growth of 81(6) kJ/mol. The crystallization of ZnAPO-47 was more complex, and the crystallization curves could not be described using simple kinetic expressions. C1 Aarhus Univ, Dept Inorgan Chem, DK-8000 Aarhus C, Denmark. Odense Univ, Dept Chem, DK-5230 Odense, Denmark. SUNY Stony Brook, Dept Chem, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Christensen, AN (reprint author), Aarhus Univ, Dept Inorgan Chem, DK-8000 Aarhus C, Denmark. RI Hanson, jonathan/E-3517-2010; Norby, Poul/B-9047-2014; OI Norby, Poul/0000-0002-2590-7050; Jensen, Torben Rene/0000-0002-4278-3221 NR 22 TC 48 Z9 49 U1 0 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD JUN PY 1998 VL 10 IS 6 BP 1688 EP 1693 DI 10.1021/cm980049s PG 6 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA ZV160 UT WOS:000074275800032 ER PT J AU Wos, L AF Wos, L TI Programs that offer fast, flawless, logical reasoning SO COMMUNICATIONS OF THE ACM LA English DT Article C1 Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. RP Wos, L (reprint author), Argonne Natl Lab, Div Math & Comp Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 12 TC 2 Z9 2 U1 0 U2 0 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036 USA SN 0001-0782 J9 COMMUN ACM JI Commun. ACM PD JUN PY 1998 VL 41 IS 6 BP 87 EP 95 DI 10.1145/276609.276624 PG 9 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA ZQ745 UT WOS:000073898800025 ER PT J AU Wei, GW Zhang, DS Kouri, DJ Hoffman, DK AF Wei, GW Zhang, DS Kouri, DJ Hoffman, DK TI A robust and reliable approach to nonlinear dynamical problems SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article ID BURGERS-EQUATION; PLANCK AB A new approach, which utilizes Gaussian Lagrange distributed approximating functionals (LDAFs) for evaluating spatial derivatives to high accuracy is proposed for solving nonlinear dynamical problems. Three different nonlinear problems (Burgers' equation, a nonlinear Fokker-Planck equation and the Korteweg-de Vries equation) are used to demonstrate the usefulness and test the accuracy of the method. It is found that the present approach is robust for a variety of different nonlinear dynamical problems, and, using equivalent parameters, is the most accurate available method for the problems which we have examined. (C) 1998 Elsevier Science B.V. C1 Univ Houston, Dept Chem, Houston, TX 77204 USA. Univ Houston, Dept Phys, Houston, TX 77204 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Wei, GW (reprint author), Univ Houston, Dept Chem, Univ Pk, Houston, TX 77204 USA. RI Wei, Guowei /E-1852-2011 NR 34 TC 10 Z9 10 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD JUN PY 1998 VL 111 IS 1-3 BP 87 EP 92 DI 10.1016/S0010-4655(98)00020-4 PG 6 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA ZY358 UT WOS:000074612700008 ER PT J AU Wei, GW Zhang, DS Kouri, DJ Hoffman, DK AF Wei, GW Zhang, DS Kouri, DJ Hoffman, DK TI Distributed approximating functional approach to Burgers' equation in one and two space dimensions SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article ID PROPAGATION; DYNAMICS; NUMBER AB The method of distributed approximating functionals (DAFs) is applied to Burgers' equation, as a typical nonlinear PDE, in one and two space dimensions. This equation is similar to, but simpler than, the Navier-Stokes equation in fluid dynamics. The present approach uses DAFs for spatial discretization and a Taylor expansion for time discretization. Several moderately large values of the Reynolds number are considered in the present application. The results obtained, which are in excellent agreement with the formally exact series solutions, are compared with those obtained by other authors using various different methods, It is found that a simple numerical propagation scheme based on DAFs provides highly accurate numerical solutions for Burgers' equation, while requiring very few grid points, (C) 1998 Elsevier Science B.V. C1 Univ Houston, Dept Chem, Houston, TX 77204 USA. Univ Houston, Dept Phys, Houston, TX 77204 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Wei, GW (reprint author), Univ Houston, Dept Chem, Univ Pk, Houston, TX 77204 USA. RI Wei, Guowei /E-1852-2011 NR 26 TC 16 Z9 16 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD JUN PY 1998 VL 111 IS 1-3 BP 93 EP 109 DI 10.1016/S0010-4655(98)00041-1 PG 17 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA ZY358 UT WOS:000074612700009 ER PT J AU Sussman, M Fatemi, E Smereka, P Osher, S AF Sussman, M Fatemi, E Smereka, P Osher, S TI An improved level set method for incompressible two-phase flows SO COMPUTERS & FLUIDS LA English DT Article; Proceedings Paper CT 6th International Symposium on Computational Fluid Dynamics CY SEP, 1995 CL LAKE TAHOE, NV SP Japan Soc Comp Fluid Dynam ID FLUID-FLOWS; ALGORITHMS; SCHEMES; BUBBLES; SURFACE AB A level set method for capturing the interface between two fluids is combined with a variable density projection method to allow for computation of a two-phase flow where the interface can merge/break and the flow can have a high Reynolds number. A distance function formulation of the level set method enables us to compute flows with large density ratios (1000/1) and flows that are surface tension driven, with no emotional involvement. Recent work has improved the accuracy of the distance function formulation and the accuracy of the advection scheme. We compute flows involving air bubbles and water drops, among others. We validate our code against experiments and theory. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Lawrence Livermore Natl Lab, Ctr Computat Sci & Engn, Livermore, CA 94550 USA. Univ Calif Los Angeles, Dept Math, Los Angeles, CA 90024 USA. Univ Michigan, Dept Math, Ann Arbor, MI 48109 USA. RP Sussman, M (reprint author), Lawrence Livermore Natl Lab, Ctr Computat Sci & Engn, Livermore, CA 94550 USA. RI Smereka, Peter/F-9974-2013 NR 21 TC 389 Z9 407 U1 4 U2 52 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0045-7930 J9 COMPUT FLUIDS JI Comput. Fluids PD JUN-JUL PY 1998 VL 27 IS 5-6 BP 663 EP 680 DI 10.1016/S0045-7930(97)00053-4 PG 18 WC Computer Science, Interdisciplinary Applications; Mechanics SC Computer Science; Mechanics GA ZT124 UT WOS:000074050800012 ER PT J AU Dwyer, HA Grcar, J AF Dwyer, HA Grcar, J TI Solution of the Navier-Stokes equation with finite-differences on unstructured triangular meshes SO COMPUTERS & FLUIDS LA English DT Article; Proceedings Paper CT 6th International Symposium on Computational Fluid Dynamics CY SEP, 1995 CL LAKE TAHOE, NEVADA SP Japan Soc Comp Fluid Dynam AB A low Mach number model of the Navier-Stokes equations has been developed for unstructured meshes. The numerical method combines many attractive features of the finite volume method and unstructured finite elements, however, inside the elements a finite difference scheme based on generalized coordinate transformations has been applied. The method of solution of the equations is a well developed pressure correction algorithm that has worked well previously for structured meshes. The physical applications in the paper include axisymmetry and two-dimensional problems, as well as variable density solutions of the Navier-Stokes equations. It is the authors' opinion that some of the methods developed in the paper may have been used by other investigators, however, we have not found references in the literature that explicitly use finite differences to solve flows on unstructured element based meshes. A major goal of the paper is to show some of the similarities between the finite element and the difference methods that are both very popular at the present time. It is hoped that these similarities will lead to better understanding and improvements in both techniques. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Davis, Davis, CA 95616 USA. Sandia Natl Labs, Livermore, CA USA. RP Dwyer, HA (reprint author), Univ Calif Davis, Davis, CA 95616 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0045-7930 J9 COMPUT FLUIDS JI Comput. Fluids PD JUN-JUL PY 1998 VL 27 IS 5-6 BP 695 EP 708 DI 10.1016/S0045-7930(97)00050-9 PG 14 WC Computer Science, Interdisciplinary Applications; Mechanics SC Computer Science; Mechanics GA ZT124 UT WOS:000074050800015 ER PT J AU Sarma, G Zacharia, T Miles, D AF Sarma, G Zacharia, T Miles, D TI Using High Performance Fortran for parallel programming SO COMPUTERS & MATHEMATICS WITH APPLICATIONS LA English DT Article DE parallel program; High Performance Fortran; finite element method; deformation process simulation; polycrystal plasticity ID CRYSTALLOGRAPHIC TEXTURE; POLYCRYSTAL PLASTICITY; SHEET; CREEP AB A finite element code with a polycrystal plasticity model for simulating deformation processing of metals has been developed for parallel computers using High Performance Fortran (HPF). The conversion of the code from an original implementation on the Connection Machine systems using CM Fortran is described. The sections of the code requiring minimal inter-processor communication are easily parallelized, by changing only the syntax for specifying data layout. However, the solver routine based on the conjugate gradient method required additional modifications, which are discussed in detail. The performance of the code on a massively parallel distributed-memory Intel PARAGON supercomputer is evaluated through timing statistics. Published by Elsevier Science Ltd. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Portland Grp Inc, Wilsonville, OR 97070 USA. RP Sarma, G (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. OI Zacharia, Thomas/0000-0001-6463-5425 NR 25 TC 5 Z9 5 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0898-1221 J9 COMPUT MATH APPL JI Comput. Math. Appl. PD JUN PY 1998 VL 35 IS 12 BP 41 EP 57 DI 10.1016/S0898-1221(98)00095-9 PG 17 WC Mathematics, Applied SC Mathematics GA ZT637 UT WOS:000074107800005 ER PT J AU Foster, I Geisler, J Nickless, B Smith, W Tuecke, S AF Foster, I Geisler, J Nickless, B Smith, W Tuecke, S TI Software infrastructure for the I-WAY metacomputing experiment SO CONCURRENCY-PRACTICE AND EXPERIENCE LA English DT Article ID SYSTEMS AB High-speed wide-area networks are expected to enable innovative applications that integrate geographically distributed, high-performance computing, database, graphics and networking resources. However, there is as yet little understanding of the higher-level services required to support these applications, or of the techniques required to implement these services in a scalable, secure manner. We report on a large-scale prototyping effort that has yielded some insights into these issues. Building on the hardware base provided by the I-WAY, a national-scale asynchronous transfer mode (ATM) network, we developed an integrated management and application programming system, called I-Soft. This system was deployed at most of the 17 I-WAY sites and used by many of the 60 applications demonstrated on the I-WAY network. In this paper we describe the I-Soft design and report on lessons learned from application experiments. We focus on four novel concepts that we believe may have relevance to future, similar systems: point of presence machines as a means of simplifying implementation and management; scheduler proxies to integrate local schedulers to computational resource brokers; authentication proxies to provide a uniform authentication environment across multiple administrative domains; and network-aware parallel programming tools to hide heterogeneity and improve performance in heterogeneous environments. Lessons learned in building I-Soft have motivated subsequent research and development efforts in the Globus project. (C) 1998 John Wiley & Sons, Ltd. C1 Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. EM foster@mc.anl.gov; geisler@mcs.anl.gov; nickless@mcs.anl.gov; wsmith@mcs.anl.gov; tuecke@mcs.anl.gov NR 27 TC 5 Z9 5 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI CHICHESTER PA THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND SN 1040-3108 J9 CONCURRENCY-PRACT EX JI Concurrency-Pract. Exp. PD JUN PY 1998 VL 10 IS 7 BP 567 EP 581 DI 10.1002/(SICI)1096-9128(199806)10:7<567::AID-CPE366>3.0.CO;2-X PG 15 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA 101RM UT WOS:000074882000003 ER PT J AU Hoyer, LL Payne, TL Bell, M Myers, AM Scherer, S AF Hoyer, LL Payne, TL Bell, M Myers, AM Scherer, S TI Candida albicans ALS3 and insights into the nature of the ALS gene family SO CURRENT GENETICS LA English DT Article DE Candida albicans; gene family; hyphal-specific; differential gene regulation ID SEQUENCE-ANALYSIS; PLASMID DNA; IN-VIVO; PROTEINS; REQUIREMENTS; CONSTRUCTION; EXPRESSION; PROLINE; ELONGATION; ATTACHMENT AB The ALS1 (agglutinin-like sequence) gene of Candida albicans encodes a protein similar to alpha-agglutinin, a cell-surface adhesion glycoprotein of Saccharomyces cerevisiae (Hoyer et al. 1995). A central domain of a tandemly repeated 108-bp sequence is found in the ALS1 coding region. This tandem-repeat motif hybridizes to multiple C. albicans genomic DNA fragments, indicating the possibility of other ALS1-like genes in C. albicans (Hoyer et al. 1995). To determine if these fragments constitute a gene family, tandem-repeat-hybridizing genomic fragments were isolated from a fosmid library by PCR screening using primers based on the consensus tandem-repeat sequence of ALS1 (Hoyer et al. 1995). One group of fosmids, designated ALS3, encodes a gene with 81% identity to ALS1. The sequences of ALS1 and ALS3 are most conserved in the tandem-repeat domain and in the region 5' of the tandem repeats, Northern-blot analysis using unique probes from the 3' end of each gene demonstrated that ALS1 expression varies, depending on which C. albicans strain is examined, and that,ALS3 is hyphal-specific. Both genes are found in a variety of C. albicans and C. stellatoidea strains examined. The predicted Als1p and Als3p exhibit features suggesting that both are cell-surface glycoproteins. Southern blots probed with conserved sequences from the region 5' of the tandem repeats suggest that other ALS-like sequences are present in the C. albicans genome and that the ALS family may be larger than originally estimated. C1 Univ Illinois, Dept Vet Pathobiol, Urbana, IL 61802 USA. Iowa State Univ Sci & Technol, Dept Biochem & Biophys, Ames, IA 50011 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Human Genome Ctr, Berkeley, CA 94720 USA. Univ Minnesota, Dept Microbiol, Minneapolis, MN 55455 USA. RP Univ Illinois, Dept Vet Pathobiol, 2522 VMBSB,2001 S Lincoln Ave, Urbana, IL 61802 USA. EM lhoyer@uiuc.edu FU NIAID NIH HHS [AI23850, AI39441] NR 39 TC 148 Z9 154 U1 0 U2 2 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0172-8083 EI 1432-0983 J9 CURR GENET JI Curr. Genet. PD JUN PY 1998 VL 33 IS 6 BP 451 EP 459 DI 10.1007/s002940050359 PG 9 WC Genetics & Heredity SC Genetics & Heredity GA 101RU UT WOS:000074882600009 PM 9644209 ER PT J AU Wang, J AF Wang, J TI Characterizing surfaces and interfaces using X-ray standing waves SO CURRENT OPINION IN COLLOID & INTERFACE SCIENCE LA English DT Review ID LATTICE LOCATION; MEMBRANES; ADSORBATE; FIELDS; LAYERS AB Since the discovery of X-ray standing waves in the 1960s, the technique has been extensively used to provide structural information about single crystal surfaces and interlaces with atomic resolution. Recently, this method has been used to elucidate the structure of organic thin films and their surfaces. More remarkably, it has proven its usefulness in characterizing aqueous/mineral interfaces in situ. C1 Argonne Natl Lab, Expt Facil Div, Argonne, IL 60439 USA. RP Wang, J (reprint author), Argonne Natl Lab, Expt Facil Div, 9700 S Cass Ave, Argonne, IL 60439 USA. EM wangj@aps.anl.gov NR 56 TC 3 Z9 3 U1 0 U2 2 PU CURRENT CHEMISTRY LTD PI LONDON PA 34-42 CLEVELAND STREET, LONDON W1P 6LE, ENGLAND SN 1359-0294 J9 CURR OPIN COLLOID IN JI Curr. Opin. Colloid Interface Sci. PD JUN PY 1998 VL 3 IS 3 BP 312 EP 320 PG 9 WC Chemistry, Physical SC Chemistry GA ZV971 UT WOS:000074360700013 ER PT J AU Hunter-Cevera, JC AF Hunter-Cevera, JC TI The value of microbial diversity SO CURRENT OPINION IN MICROBIOLOGY LA English DT Review ID 16S RIBOSOMAL-RNA; BACTERIAL GENOMES; UNITED-STATES; FERROUS IRON; BIODIVERSITY; BIOTECHNOLOGY; OXIDATION; SEQUENCES; ARCHAEA; OCEAN AB In the past few years, due to the use of molecular methods, our knowledge of microbial diversity has increased dramatically, not only from a phylogenetic and taxonomic perspective but also from an ecological basis. We now know that microorganisms exist in every conceivable place on Earth, even in extreme environments. Temperature may be the only limitation as to where they can and cannot exist and/or function. As more small subunit rDNA sequence information becomes available there is a real need to start turning the information into knowledge that can be applied to better elucidate and understand structure-function relationships within ecosystems, develop new culturing methods, and discover new products and processes. It has been stated on numerous occasions that the 21(st) century is the century for biology. Within that context, we must address the real value of microbial diversity. C1 Ernest Orlando Lawrence Berkeley Natl Lab, Ctr Environm Biotechnol, Berkeley, CA 94720 USA. RP Hunter-Cevera, JC (reprint author), Ernest Orlando Lawrence Berkeley Natl Lab, Ctr Environm Biotechnol, Bldg 70A-MS3317,1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 41 TC 20 Z9 21 U1 0 U2 5 PU CURRENT BIOLOGY LTD PI LONDON PA 34-42 CLEVELAND STREET, LONDON W1P 6LB, ENGLAND SN 1369-5274 J9 CURR OPIN MICROBIOL JI Curr. Opin. Microbiol. PD JUN PY 1998 VL 1 IS 3 BP 278 EP 285 DI 10.1016/S1369-5274(98)80030-1 PG 8 WC Microbiology SC Microbiology GA 117DK UT WOS:000075765200003 PM 10066499 ER PT J AU White, DC Phelps, TJ Onstott, TC AF White, DC Phelps, TJ Onstott, TC TI What's up down there? SO CURRENT OPINION IN MICROBIOLOGY LA English DT Review ID DEEP SUBSURFACE; MICROBIAL COLONIZATION; LIFE; MICROORGANISMS; BIODIVERSITY; CONSTRAINTS; BACTERIA; AQUIFER; BIOMASS AB The development of careful quality assurance criteria assuring freedom from contamination in all aspects of sample recovery has opened the window to studies of a fascinating new microbial biome in the deep subsurface. Organisms have been recovered with unusual metabolic capabilities and a chemosynthetic lifestyle independent of the recent surface photosynthetically derived energy inputs. The properties of the subsurface microbiota are critical when assessing aspects such as the utility of burying radioactive waste, the remediation of mixtures of organics, metals, and nuclides, and the search for life in extreme environments on Earth as well as on Mars and other extraterrestrial sites. In addition this pioneering work provides a foundation for examining life processes in extreme environments, such as the environment beneath the ocean floor. C1 Univ Tennessee, Ctr Environm Biotechnol, Knoxville, TN 37932 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Princeton Univ, Dept Geol, Princeton, NJ 08544 USA. RP White, DC (reprint author), Univ Tennessee, Ctr Environm Biotechnol, 10515 Res Dr,Suite 300, Knoxville, TN 37932 USA. EM milipids@aol.com RI phelps, tommy/A-5244-2011 NR 32 TC 27 Z9 30 U1 0 U2 14 PU CURRENT BIOLOGY LTD PI LONDON PA 34-42 CLEVELAND STREET, LONDON W1P 6LB, ENGLAND SN 1369-5274 J9 CURR OPIN MICROBIOL JI Curr. Opin. Microbiol. PD JUN PY 1998 VL 1 IS 3 BP 286 EP 290 DI 10.1016/S1369-5274(98)80031-3 PG 5 WC Microbiology SC Microbiology GA 117DK UT WOS:000075765200004 PM 10066493 ER PT J AU Embury, JD Han, K AF Embury, JD Han, K TI Conductor materials for high field magnets SO CURRENT OPINION IN SOLID STATE & MATERIALS SCIENCE LA English DT Review ID IN-SITU COMPOSITES; AG ALLOY SHEETS; HIGH-STRENGTH; COPPER; MICROSTRUCTURE; COILS; WIRES AB High field magnets require the development and fabrication of large quantities of wire which possess both high strength and high electrical conductivity (the latter is usually expressed as a percentage of the IACS, international annealed copper standard, where 100%IACS = 1.7241 mu Omega cm). This combination of properties can be obtained by the co-deformation of a variety of materials either in macroscopic form or in the form of as-solidified composites. A number of these materials have strength levels close to the theoretical strength and thus require detailed consideration of the mechanisms of strengthening which operate in materials with ultra fine scale microstructures. In addition, consideration must be given to the development of rational systems of design for the selection and fabrication of materials for use in high field magnets. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Embury, JD (reprint author), Univ Calif Los Alamos Natl Lab, Mail Stop K765, Los Alamos, NM 87545 USA. EM embury@lanl.gov; hanke@lanl.gov NR 47 TC 33 Z9 34 U1 2 U2 10 PU CURRENT CHEMISTRY LTD PI LONDON PA 34-42 CLEVELAND STREET, LONDON W1P 6LE, ENGLAND SN 1359-0286 J9 CURR OPIN SOLID ST M JI Curr. Opin. Solid State Mat. Sci. PD JUN PY 1998 VL 3 IS 3 BP 304 EP 308 DI 10.1016/S1359-0286(98)80106-X PG 5 WC Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 100AA UT WOS:000074790700014 ER PT J AU Bork, P Eisenberg, D AF Bork, P Eisenberg, D TI Sequences and topology - Deriving biological knowledge from genomic sequences SO CURRENT OPINION IN STRUCTURAL BIOLOGY LA English DT Editorial Material C1 European Mol Biol Lab, D-69012 Heidelberg, Germany. Univ Calif Los Angeles, Inst Mol Biol, UCLA DOE Lab Struct Biol & Mol Med, Los Angeles, CA 90095 USA. RP Bork, P (reprint author), European Mol Biol Lab, Meyerhofstr 1,102209, D-69012 Heidelberg, Germany. RI Bork, Peer/F-1813-2013 OI Bork, Peer/0000-0002-2627-833X NR 0 TC 7 Z9 7 U1 0 U2 2 PU CURRENT BIOLOGY LTD PI LONDON PA 34-42 CLEVELAND STREET, LONDON W1P 6LB, ENGLAND SN 0959-440X J9 CURR OPIN STRUC BIOL JI Curr. Opin. Struct. Biol. PD JUN PY 1998 VL 8 IS 3 BP 331 EP 332 DI 10.1016/S0959-440X(98)80066-3 PG 2 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA ZX965 UT WOS:000074573200009 ER PT J AU Nagy, P Bene, L Balazs, M Hyun, WC Lockett, SJ Chiang, NY Waldman, F Feuerstein, BG Damjanovich, S Szollosi, J AF Nagy, P Bene, L Balazs, M Hyun, WC Lockett, SJ Chiang, NY Waldman, F Feuerstein, BG Damjanovich, S Szollosi, J TI EGF-induced redistribution of erbB2 on breast tumor cells: Flow and image cytometric energy transfer measurements SO CYTOMETRY LA English DT Article DE erbB2; EGF receptor; energy transfer; homoassociation; breast cancer ID GROWTH-FACTOR RECEPTOR; MHC CLASS-I; SIGNAL-TRANSDUCTION; MONOCLONAL-ANTIBODY; NEU GENE; HEREGULIN; SURFACE; CANCER; ASSOCIATION; MOLECULES AB erbB2, a member of the epidermal growth factor (EGF) receptor-type tyrosine kinase receptor family, is overexpressed in breast carcinomas with poor prognosis. We examined the cell surface association of this receptor with itself and with other cell surface proteins by the Forster-type fluorescence resonance energy transfer using whole antibodies and Fab fragments. We found that erbB2 molecules homoassociate in unstimulated SK-BR-S, BT474 and BT474-M (a metastatic version of the parent BT474 line) breast tumor cells, and that the interaction was enhanced by EGF treatment in suspensions of SK-BR-3 and BT474-M cells, BT474 cells (with low EGF receptor expression) and attached SK-BR-S cells do not respond to EGF, Image microscopic energy transfer measurements found considerable pixel-by-pixel heterogeneity in the homoassociation state of erbB2, In accordance with the EGF-induced redistribution of erbB2, EGF receptor was found to be in close proximity to erbB2 in FRET measurements. By labeling different epitopes on erbB2 and the lipid bilayer, we were able to prepare an epitope map of erbB2 molecule. Our data suggest the existence of dynamic cell surface patterns of erbB2 and point to functions fulfilled by these molecular complexes. (C) 1998 Wiley-Liss, Inc. C1 Debrecen Univ Med, Sch Med, Dept Biophys & Cell Biol, H-4012 Debrecen, Hungary. Debrecen Univ Med, Sch Med, Dept Hyg, H-4012 Debrecen, Hungary. Univ Calif San Francisco, Ctr Canc, Div Canc Genet, San Francisco, CA 94143 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA USA. Genentech Inc, S San Francisco, CA 94080 USA. RP Szollosi, J (reprint author), Debrecen Univ Med, Sch Med, Dept Biophys & Cell Biol, POB 39, H-4012 Debrecen, Hungary. EM szollo@jaguar.dote.hu RI Damjanovich, Sandor/A-9284-2011; Nagy, Peter/D-2188-2013 OI Nagy, Peter/0000-0002-7466-805X NR 52 TC 36 Z9 36 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 JUN 1 PY 1998 VL 32 IS 2 BP 120 EP 131 DI 10.1002/(SICI)1097-0320(19980601)32:2<120::AID-CYTO7>3.0.CO;2-P PG 12 WC Biochemical Research Methods; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA ZR114 UT WOS:000073937700007 PM 9627225 ER PT J AU Bryndorf, T AF Bryndorf, T TI Development and clinical studies of in situ hybridization techniques in prenatal diagnosis SO DANISH MEDICAL BULLETIN LA English DT Review ID FLUORESCENCE INSITU HYBRIDIZATION; COMPARATIVE GENOMIC HYBRIDIZATION; AMNIOTIC-FLUID CELLS; ALPHA-SATELLITE DNA; MOLECULAR CYTOGENETIC ANALYSIS; CHORIONIC VILLUS CELLS; LOW-RISK WOMEN; UNCULTURED AMNIOCYTES; DOWNS-SYNDROME; RAPID DETECTION C1 Rigshosp, Clin Genet Sect, Chromosome Lab, DK-2100 Copenhagen, Denmark. Lawrence Livermore Natl Lab, Div Biomed Sci, Cytophys Sect, Livermore, CA USA. Becton Dickinson Immunocytometry Syst, San Jose, CA 95131 USA. RP Granholmen 28, DK-2840 Holte, Denmark. NR 127 TC 2 Z9 2 U1 0 U2 0 PU DANISH MEDICAL ASSOC PI COPENHAGEN PA TRONDHJEMSGADE 9, DK-2100 COPENHAGEN, DENMARK SN 0907-8916 EI 1603-9629 J9 DAN MED BULL JI Dan. Med. Bull. PD JUN PY 1998 VL 45 IS 3 BP 298 EP 312 PG 15 WC Medicine, General & Internal SC General & Internal Medicine GA 100ZH UT WOS:000074844800005 PM 9675541 ER PT J AU Bedell, MA Sripriya, R Davis, WS Jimenez, HK Russell, LB AF Bedell, MA Sripriya, R Davis, WS Jimenez, HK Russell, LB TI Cell-restricted effects of structural mutations in Steel growth factor of mice SO DEVELOPMENTAL BIOLOGY LA English DT Meeting Abstract C1 Univ Georgia, Dept Genet, Athens, GA 30602 USA. Oak Ridge Natl Lab, Oak Ridge, TN USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0012-1606 J9 DEV BIOL JI Dev. Biol. PD JUN 1 PY 1998 VL 198 IS 1 MA 311 BP 211 EP 211 PG 1 WC Developmental Biology SC Developmental Biology GA ZV215 UT WOS:000074281900314 ER PT J AU Gatley, SJ Volkow, ND AF Gatley, SJ Volkow, ND TI Addiction and imaging of the living human brain SO DRUG AND ALCOHOL DEPENDENCE LA English DT Review ID POSITRON EMISSION TOMOGRAPHY; CEREBRAL BLOOD-FLOW; BENZODIAZEPINE-RECEPTOR-BINDING; DEFICIT HYPERACTIVITY DISORDER; GLUCOSE-UTILIZATION; DOPAMINE TRANSPORTER; FRONTAL HYPOMETABOLISM; SCHIZOPHRENIC SUBJECTS; AMPHETAMINE CHALLENGE; ALCOHOL-INTOXICATION C1 Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. RP Gatley, SJ (reprint author), Brookhaven Natl Lab, Dept Med, 490 Bell Ave, Upton, NY 11973 USA. NR 109 TC 21 Z9 22 U1 0 U2 0 PU ELSEVIER SCI IRELAND LTD PI CLARE PA CUSTOMER RELATIONS MANAGER, BAY 15, SHANNON INDUSTRIAL ESTATE CO, CLARE, IRELAND SN 0376-8716 J9 DRUG ALCOHOL DEPEN JI Drug Alcohol Depend. PD JUN-JUL PY 1998 VL 51 IS 1-2 BP 97 EP 108 DI 10.1016/S0376-8716(98)00069-6 PG 12 WC Substance Abuse; Psychiatry SC Substance Abuse; Psychiatry GA 103DK UT WOS:000075142600011 PM 9716933 ER PT J AU Newman, MC Jagoe, RH AF Newman, MC Jagoe, RH TI Allozymes reflect the population-level effect of mercury: simulations of the mosquitofish (Gambusia holbrooki Girard) GPI-2 response SO ECOTOXICOLOGY LA English DT Article DE fish; mercury; natural selection; allozyme; population ID KREBS CYCLE METABOLITES; INORGANIC MERCURY; PHOSPHOGLUCOSE ISOMERASE; COLIAS BUTTERFLIES; MARINE ORGANISMS; AFFINIS BAIRD; LIFE-HISTORY; ENZYME LOCI; SELECTION; ADAPTATION AB Measurements of the differential tolerance between enzyme genotypes and shifts in allozyme frequencies in populations from contaminated habitats have prompted the use of allozymes as markers of population-level toxicant effects. However, such studies often do not consider other factors that influence allele frequencies, including natural clines, migration, the intensity and specificity of selection and toxicant-induced genetic bottlenecks. In addition, selection components other than survival are not included. Consequently, the associated conclusions remain speculative. To assess this approach rigorously, a simulation study was conducted with the mosquitofish (Gambusia holbrooki) GPI-2 locus. Laboratory studies have shown the GPI-2(38/38) homozygote at this locus to be less tolerant than other genotypes during acute exposure to mercury. The GPI-2(100/100) genotype has also been shown to have a reproductive disadvantage at lower mercury concentrations. Simple and then more complex models were used to quantify the relative effects of viability selection, random genetic drift and migration on the GPI-2(38) allele frequency. Simulations were also performed to assess the contribution of sexual and fecundity selection. A simple population model suggested that viability selection plays a greater role than does mortality-driven, genetic drift in the decrease of the sensitive allele under the conditions of this study. A more complex, stochastic model indicated that no significant mortality-driven drift was taking place in this system. In both models, migration mitigated the effect of selection. Sexual and fecundity selection had little effect on the allele frequencies in these simulations. We conclude that, provided the system under study is clearly understood, shifts in allele frequency can indicate the population-level effects of pollutants. C1 Coll William & Mary, Sch Marine Sci, Virginia Inst Marine Sci, Gloucester Point, VA 23062 USA. Univ Georgia, Savannah River Ecol Lab, Aiken, SC 29802 USA. RP Newman, MC (reprint author), Coll William & Mary, Sch Marine Sci, Virginia Inst Marine Sci, Gloucester Point, VA 23062 USA. NR 51 TC 13 Z9 15 U1 1 U2 7 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0963-9292 J9 ECOTOXICOLOGY JI Ecotoxicology PD JUN PY 1998 VL 7 IS 3 BP 141 EP 150 DI 10.1023/A:1014352226686 PG 10 WC Ecology; Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA ZN243 UT WOS:000073626200003 ER PT J AU Quesada, MA Dhadwal, HS Fisk, D Studier, FW AF Quesada, MA Dhadwal, HS Fisk, D Studier, FW TI Multi-capillary optical waveguides for DNA sequencing SO ELECTROPHORESIS LA English DT Article DE capillary electrophoresis; DNA sequencing ID REPLACEABLE LINEAR POLYACRYLAMIDE; LASER-INDUCED FLUORESCENCE; ARRAY ELECTROPHORESIS; FRAGMENTS; SEPARATION AB Cylindrial capillaries can be used as optical elements in a waveguide, where refraction will confine an appropriately focused light beam to pass through the interiors of successive capillaries in a flat parallel array. Such a capillary waveguide allows efficient illumination of samples in multiple capillaries with relatively little laser power. Analytical expressions derived under paraxial and thin-lens approximations provide guidance in selecting the capillary sizes and the refractive indices that will produce the waveguiding effect, but accurate predictions require exact ray tracing. Small reflective losses as the light passes through the capillary surfaces cause cumulative intensity decreases, but the resulting lack of uniformity can be compensated to a considerable extent by illuminating the capillary array from both sides. A 12-capillary waveguide illuminated from both sides in air has a difference of less than 10% from the strongest to the weakest illumination. By increasing the refractive index of both the external medium and the contents of the capillaries, a 96-capillary waveguide for DNA sequencing could be produced that would also provide nearly uniform illumination. A 12-capillary, bi-directionally illuminated waveguide system for DNA sequencing has been constructed. The two focused laser beams are delivered by integrated fiber optic transmitters (IFOTs), and fluorescence is collected by a set of optical fibers whose spacing exactly matches that of the capillaries in the waveguide. The system is easy to align and provides sensitive detection of fluorescence with minimal cross-talk between channels. C1 Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. SUNY Stony Brook, Dept Elect Engn, Stony Brook, NY 11794 USA. RP Quesada, MA (reprint author), Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. NR 26 TC 25 Z9 25 U1 2 U2 4 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0173-0835 J9 ELECTROPHORESIS JI Electrophoresis PD JUN PY 1998 VL 19 IS 8-9 BP 1415 EP 1427 DI 10.1002/elps.1150190836 PG 13 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA ZY715 UT WOS:000074652100036 PM 9694291 ER PT J AU Vine, EL Murakoshi, C Nakagami, H AF Vine, EL Murakoshi, C Nakagami, H TI International ESCO business opportunities and challenges: A Japanese case study SO ENERGY LA English DT Article AB U.S. energy service companies (ESCOs) are very interested in expanding their businesses outside the U.S. Despite the needs of many countries for ESCO involvement, ESCOs face many challenges (i.e. marketing, financial, institutional, political and cultural impediments). Using Japan as an example, we present (i) impediments to the development of an ESCO industry, (ii) general guidance for helping Japan to develop its own ESCO industry, (iii) specific ESCO development strategies for Japan, and (iv) recommendations to U.S. companies considering joint ventures between U.S. ESCOs and Japanese companies. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Jyukankyo Res Inst, Tokyo, Japan. RP Vine, EL (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Bldg 90-2000, Berkeley, CA 94720 USA. NR 4 TC 21 Z9 22 U1 0 U2 9 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0360-5442 J9 ENERGY JI Energy PD JUN PY 1998 VL 23 IS 6 BP 439 EP 447 DI 10.1016/S0360-5442(98)00008-5 PG 9 WC Thermodynamics; Energy & Fuels SC Thermodynamics; Energy & Fuels GA 101TY UT WOS:000074885300002 ER PT J AU Walker, IS Wilson, DJ Sherman, MH AF Walker, IS Wilson, DJ Sherman, MH TI A comparison of the power law to quadratic formulations for air infiltration calculations SO ENERGY AND BUILDINGS LA English DT Article DE power law; air infiltration calculations; building envelope air flow; fan pressurization (blower door) testing ID FLOW AB Although the power law has been broadly accepted in measurement and air infiltration standards, and in many air infiltration calculation methods, assumption that the power law is true over the range of pressures that a building envelope experiences has not been well documented. In this paper, we examine the validity of the power law through theoretical analysis, laboratory measurements of crack flow and detailed held tests of building envelopes. The results of the theoretical considerations and held and laboratory measurements indicate that the power law is valid for low pressure building envelope leakage. (C) Published by Elsevier Science S.A. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Energy & Environm, Energy Performance Bldg Grp, Berkeley, CA 94720 USA. RP Walker, IS (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Energy & Environm, Energy Performance Bldg Grp, Berkeley, CA 94720 USA. NR 19 TC 24 Z9 25 U1 0 U2 9 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0378-7788 J9 ENERG BUILDINGS JI Energy Build. PD JUN PY 1998 VL 27 IS 3 BP 293 EP 299 DI 10.1016/S0378-7788(97)00047-9 PG 7 WC Construction & Building Technology; Energy & Fuels; Engineering, Civil SC Construction & Building Technology; Energy & Fuels; Engineering GA ZF636 UT WOS:000072916900010 ER PT J AU Dooley, JJ AF Dooley, JJ TI Unintended consequences: energy R & D in a deregulated energy market SO ENERGY POLICY LA English DT Article DE energy policy; deregulation; utility R & D AB Many advanced industrialized nations are substantially reducing their national (public and private) investments in energy research and development (R&D), driven in part by changes occurring as a result of the deregulation of these nations' energy sectors, In particular, funding for strategic energy R&D aimed at developing future energy supply options (eg, fusion, fission,'clean' fossil energy, renewable energy) has been decreased substantially in both the public and private sectors in many of these nations. These trends are now starting to be seen in the United States as it moves towards the deregulation of the nation's utilities. The magnitude of the reductions in support for energy R&D in the public and private sectors and the shift towards decidedly shorter-term R&D has profound implications for nations approaching deregulation. Though utility customers may be short-term winners from the deregulation of utilities by paying less for energy, a national failure to invest in energy R&D is very likely to have long-term negative impacts on national energy sectors, the economies, and environmental wellbeing. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Pacific NW Natl Lab, Washington, DC 20024 USA. RP Dooley, JJ (reprint author), Pacific NW Natl Lab, 901 D St SW,Suite 900, Washington, DC 20024 USA. OI Dooley, James/0000-0002-2824-4344 NR 26 TC 47 Z9 48 U1 1 U2 5 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 JUN PY 1998 VL 26 IS 7 BP 547 EP 555 DI 10.1016/S0301-4215(97)00166-3 PG 9 WC Energy & Fuels; Environmental Sciences; Environmental Studies SC Energy & Fuels; Environmental Sciences & Ecology GA ZY574 UT WOS:000074637300004 ER PT J AU McKenna, SA AF McKenna, SA TI Geostatistical approach for managing uncertainty in environmental remediation of contaminated soils: Case study SO ENVIRONMENTAL & ENGINEERING GEOSCIENCE LA English DT Article DE pollution remediation; modeling/statistics; pollution modeling; site investigations; hazardous waste (management); simulation; environmental geology ID GROUNDWATER CONTAMINATION; PROBABILISTIC ASSESSMENT AB Variability in the spatial distribution of soil contaminants and limited (non-exhaustive) sampling create uncertainty in planned remediation activities at a site. Geostatistical simulation techniques can be applied to existing data to map the probability of exceeding a regulatory threshold (action level) across the site. This probability map can be used to devise a remediation plan based on an allowable probability of exceeding the regulatory action level that is acceptable to regulators and stakeholders. Compared with the traditional, deterministic approach to defining areas to be remediated, this probabilistic approach requires an acknowledgment of a nonzero probability of failure (failing to remove material actually exceeding the action level) that must be agreed upon by the regulators and stakeholders. Evaluation of costs for remediation alternatives and for potential regulatory failure can be combined with probability maps to provide site operators, regulators and stakeholders with cost-risk information from which key decisions can be effectively understood and negotiated. Approximately 300 samples were collected from a site in central New Mexico. These samples show concentrations of lead ranging from the 0.1 to 3,000 ppm. Initial negotiations with stakeholders and regulators resulted in two action levels being considered where each action level defined an acceptable human health risk for a residential or a industrial future land-use scenario. Probability-of-exceedence maps were created through geostatistical simulation at both action levels. Maps of areas to be remediated for several acceptable probabilities of exceedence, and the corresponding remediation costs as a function of proposed action level allowed the regulators and stakeholders to see clearly the economic consequences of their decisions. In the final decision, the regulators and stakeholders accepted a higher action level and a remediation map constructed with a five percent probability of exceedence. The cost difference between the selected action level, corresponding to an industrial future land-use scenario, and the alternative action level, corresponding to a residential future land-use scenario resulted in a projected savings in remediation costs of approximately $6.6 million. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP McKenna, SA (reprint author), Sandia Natl Labs, POB 5800,MS1324, Albuquerque, NM 87185 USA. NR 8 TC 12 Z9 13 U1 0 U2 3 PU ASSOC ENGINEERING GEOLOGISTS GEOLOGICAL SOCIETY AMER PI COLLEGE STN PA TEXAS A & M UNIV, DEPT GEOLOGY & GEOPHYSICS, COLLEGE STN, TX 77843-3115 USA SN 1078-7275 J9 ENVIRON ENG GEOSCI JI Environ. Eng. Geosci. PD SUM PY 1998 VL 4 IS 2 BP 175 EP 184 PG 10 WC Engineering, Environmental; Engineering, Geological; Geosciences, Multidisciplinary SC Engineering; Geology GA 219NA UT WOS:000081612300003 ER PT J AU Chen, ZY Yeh, JT AF Chen, ZY Yeh, JT TI A sorbent regenerator simulation model in copper oxide flue gas cleanup processes SO ENVIRONMENTAL PROGRESS LA English DT Article ID MECHANISM AB Sorbent regeneration is an important step in copper oxide flue gas cleanup processes because poor regeneration performance could require higher sorbent circulation rate and inventory resulting in increased process costs. This article describes a countercurrent moving-bed regenerator model using natural gas as the reducing agent. The model incorporates several aspects important for predicting, the regenerator performance, such as gas expansion effects, deviation from first-order kinetics with respect to copper sulfate and mass transfer limitations. The sorbent residence time predicted by this model is in good agreement with data obtained from the life-cycle test system at the Federal Energy Technology Center. The tests conducted include effects of reactor temperature, the methane to copper sulfate feed ratio, and sorbent residence time, on sorbent regeneration. The regenerator modeling also details the impact of gas velocity on the reactor performance. C1 Sci Applicat Int Corp, Reston, VA 20190 USA. US DOE, Pittsburgh Energy Technol Ctr, Pittsburgh, PA 15236 USA. RP Chen, ZY (reprint author), Sci Applicat Int Corp, 11251 Roger Bacon Dr, Reston, VA 20190 USA. NR 12 TC 7 Z9 8 U1 0 U2 1 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0278-4491 J9 ENVIRON PROG JI Environ. Prog. PD SUM PY 1998 VL 17 IS 2 BP 61 EP 69 DI 10.1002/ep.670170210 PG 9 WC Engineering, Environmental; Engineering, Chemical; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 104VL UT WOS:000075036700004 ER PT J AU Petersen, JN Bereded-Samuel, Y AF Petersen, JN Bereded-Samuel, Y TI The effect of oxygen exposure on the methanogenic activity of an anaerobic bacterial consortium SO ENVIRONMENTAL PROGRESS LA English DT Article ID SP STRAIN KC; DENITRIFICATION CONDITIONS; CARBON-TETRACHLORIDE; GRANULAR SLUDGE; MIXED CULTURES; TRANSFORMATION; DEHALOGENATION; CHEMOSTATS; COLUMN AB Due to industrial, agricultural, and defense operations, chlorinated solvents, and their natural transformation products, have been found in drinking water, wastewater, and ground water throughout the industrialized world [1]. Further, such compounds represent the most prevalent organic groundwater contaminants in the U.S. [2]. Because many are priority pollutants and/or suspected carcinogens or mutagens, the movement, transformation, and fate of these contaminants in the environment is of interest [3]. For these compounds, in situ bioremediation has the potential to substantially reduce cleanup duration and cost, when compared with traditional pump-and-treat technologies [4]. C1 Washington State Univ, Dept Chem Engn, Pullman, WA 99164 USA. Pacific NW Lab, Bioproc Grp, Richland, WA 99352 USA. RP Petersen, JN (reprint author), Washington State Univ, Dept Chem Engn, Pullman, WA 99164 USA. RI Petersen, James/B-8924-2008 NR 33 TC 6 Z9 6 U1 0 U2 2 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0278-4491 J9 ENVIRON PROG JI Environ. Prog. PD SUM PY 1998 VL 17 IS 2 BP 104 EP 110 DI 10.1002/ep.670170217 PG 7 WC Engineering, Environmental; Engineering, Chemical; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 104VL UT WOS:000075036700011 ER PT J AU Rothmel, RK Peters, RW St Martin, E Deflaun, MF AF Rothmel, RK Peters, RW St Martin, E Deflaun, MF TI Surfactant foam bioaugmentation technology for in situ treatment of TCE-DNAPLs SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID ENHANCED SOLUBILIZATION; RESIDUAL DODECANE; SOIL COLUMNS; REMEDIATION; TRANSPORT; GROUNDWATER; WATER; GAS AB Chlorinated solvents such as trichloroethylene (TCE) are prevalent aquifer contaminants. Depending on the degree of contamination, their physical properties may cause them to occur as dense nonaqueous-phase liquids (DNAPLs) making them difficult to remediate by pump-and-treat methods. Successful in situ bioremediation requires mobilization and dispersion of DNAPLs in order to reduce sediment concentrations to levels nontoxic to degradative bacteria. A bench-scale study was conducted to evaluate a novel remediation technology that utilized surfactant foam for mobilizing and dispersing TCE DNAPLs combined with a bioaugmentation technology to remediate TCE in situ. Results using the anionic surfactant Steol CS-330 showed that foam injected into TCE-DNAPL-contaminated sand columns enhanced mobilization of TCE-DNAPLs. Mobilization was maximized when the foam was injected in a pulsed operation. Injection of foam followed by artificial groundwater (AGW) and then by foam again resulted in flushing 75% of the initial TCE-DNAPL through an 8-in. column (884 cm(3) of sand). The residual TCE was dispersed within the column at concentration levels compatible with biodegradation (<500 mu g/g). Adding the TCE-degrading bacterial strain ENV 435 simultaneously with the second pulse of foam resulted in 95-99% degradation of the residual TCE. This level of remediation was achieved with a total of 3 pore volumes (foam/AGW/foam + bacteria) and an aqueous column retention time of 1 h. C1 Envirogen Inc, Lawrenceville, NJ 08648 USA. Argonne Natl Lab, Argonne, IL 60349 USA. RP Deflaun, MF (reprint author), Envirogen Inc, 4100 Quakerbridge Rd, Lawrenceville, NJ 08648 USA. EM deflaun@envirogen.com NR 31 TC 59 Z9 62 U1 1 U2 19 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 JUN 1 PY 1998 VL 32 IS 11 BP 1667 EP 1675 DI 10.1021/es970980w PG 9 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA ZR951 UT WOS:000074032700036 ER PT J AU Stewart, AJ Konetsky, BK AF Stewart, AJ Konetsky, BK TI Longevity and reproduction of Ceriodaphnia dubia in receiving waters SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE Ceriodaphnia dubia; ambient toxicity testing; daphnid ecology; biomonitoring ID POPULATION-DYNAMICS; AMBIENT TOXICITY; FOOD QUALITY; BODY-SIZE; DAPHNIA; ZOOPLANKTON; SEDIMENTS; CHLORINE; STREAM; TESTS AB Seven-day tests with Ceriodaphnia dubia are commonly used to estimate toxicity of effluents or receiving waters but can sometimes yield no toxicity outcomes even if pollutants are present. We conducted two sets of full life-cycle tests with C. dubia to (1) determine whether tests with longer exposure periods to low concentrations of contaminants in ambient water might reveal evidence of toxicity that could not be discerned from 7-d tests and (2) determine the relative importance of water quality versus food as factors influencing C. dubia longevity and reproduction. In the first set of tests, C. dubia was reared in diluted mineral water (a negative control), water from a stream impacted by coal fly-ash, or water from a retention basin containing sediments contaminated with mercury, other metals, and polychlorinated biphenyls. The second set of tests used water from the retention basin only. Before testing, though, water in the second set of tests was either filtered or not filtered, and food was either added or not added. Ceriodaphnia dubia longevity and reproduction did not differ much among the three water types in the first set of tests, but both longevity and reproduction were strongly affected by the filtering and food-addition treatments in the second set of tests. Thus, C. dubia appeared to be relatively insensitive to general water quality factors bur sensitive to food-related factors. In five of the six full life-cycle tests, lifetime reproduction by C. dubia could not be reliably predicted from reproduction data from the first 7 d of testing (R-2 < 0.35, by regression analysis). The increase in predictability of lifetime reproduction of C. dubia as a function of test duration also differed among water types in the first set of tests and among treatments in the second set of tests. Thus, it may not be possible to reliably extrapolate the results of 7-d tests with C. dubia to longer time scales. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Stewart, AJ (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. OI stewart, arthur/0000-0003-1968-5997 NR 38 TC 17 Z9 17 U1 0 U2 3 PU SETAC PRESS PI PENSACOLA PA 1010 NORTH 12TH AVE, PENSACOLA, FL 32501-3370 USA SN 0730-7268 J9 ENVIRON TOXICOL CHEM JI Environ. Toxicol. Chem. PD JUN PY 1998 VL 17 IS 6 BP 1165 EP 1171 DI 10.1897/1551-5028(1998)017<1165:LAROCD>2.3.CO;2 PG 7 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA ZN878 UT WOS:000073692600025 ER PT J AU Blower, PJ Lam, ASK O'Doherty, MJ Kettle, AG Coakley, AJ Knapp, FF AF Blower, PJ Lam, ASK O'Doherty, MJ Kettle, AG Coakley, AJ Knapp, FF TI Pentavalent rhenium-188 dimercaptosuccinic acid for targeted radiotherapy: synthesis and preliminary animal and human studies SO EUROPEAN JOURNAL OF NUCLEAR MEDICINE LA English DT Article DE rhenium-188; dimercaptosuccinic acid; bone metastases; medullary thyroid carcinoma ID TUMOR-SEEKING AGENT; MEDULLARY CARCINOMA; METASTASES; DOSIMETRY; TOXICITY; DMSA AB Pentavalent rhenium-188 dimercaptosuccinic acid [Re-188(V)DMSA] is a beta-emitting analogue of Tc-99m(V)DMSA, a tracer that is taken up in a variety of tumours and bone metastases. The aim of this study was to develop the kit-based synthesis of the agent on a therapeutic scale, to assess its stability in vivo, and to obtain preliminary biodistribution and dosimetry estimates, prior to evaluation of its potential as a targeted radiotherapy agent. The organ distribution of Re-188 in mice was determined 2 h after injection of 3 MBq Re-188(V)DMSA prepared from eluate from a W-188/Re-188 generator. Three patients with cancer of the prostate and three with cancer of the bronchus, all with bone metastases confirmed with a standard Tc-99m-hydroxymethylene diphosphonate (Tc-99m-HDP) scan, were given 370 MBq Re-188(V)DMSA and imaged at 3 h and 24 h using the 155-keV gamma-photon (15%). Blood and urine samples were collected to determine clearance and to analyse the speciation of Re-188. Organ residence times were estimated from the scans, and used to estimate radiation doses using MIRDOSE 3. In mice,Re-188(V)DMSA was selective for bone and kidney. In patients, it showed selectivity for bone metastases (particularly those from prostate carcinoma) and kidney, but uptake in normal bone was not significantly greater than in surrounding soft tissues. Of the normal tissues the kidneys received the highest radiation dose (0.5-1.3 mGy/MBq). The images were strongly reminiscent of 99mTc(V)DMSA scans in similar patients. High-performance liquid chromatography analysis of blood and urine showed no evidence of Re-188 in any chemical form other than Re-188(V)DMSA up to 24 h. In conclusion, Re-188(V)DMSA and its Re-186 analogue warrant further clinical assessment as generator/kit-derived agents for treatment of painful bone metastases. These agents should also be assessed in medullary thyroid carcinoma and other soft tissue tumours which have been shown to accumulate Tc-99m(`V)DMSA. C1 Kent & Canterbury Hosp, Dept Nucl Med, Canterbury CT1 3NG, Kent, England. Univ Kent, Dept Biosci, Canterbury, Kent, England. Oak Ridge Natl Lab, Nucl Med Grp, Oak Ridge, TN USA. RP Blower, PJ (reprint author), Kent & Canterbury Hosp, Dept Nucl Med, Canterbury CT1 3NG, Kent, England. NR 34 TC 53 Z9 55 U1 0 U2 5 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0340-6997 J9 EUR J NUCL MED JI Eur. J. Nucl. Med. PD JUN PY 1998 VL 25 IS 6 BP 613 EP 621 DI 10.1007/s002590050263 PG 9 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA ZW281 UT WOS:000074393900009 PM 9618576 ER PT J AU Acciarri, M Adriani, O Aguilar-Benitez, M Ahlen, S Alcaraz, J Alemanni, G Allaby, J Aloisio, A Alverson, G Alviggi, MG Ambrosi, G Anderhub, H Andreev, VP Angelescu, T Anselmo, F Arefiev, A Azemoon, T Aziz, T Bagnaia, P Baksay, L Banerjee, S Banerjee, S Banicz, K Barczyk, A Barillere, R Barone, L Bartalini, P Baschirotto, A Basile, M Battiston, R Bay, A Becattini, F Becker, U Behner, F Berdugo, J Berges, P Bertucci, B Betev, BL Bhattacharya, S Biasini, M Biland, A Bilei, GM Blaising, JJ Blyth, SC Bobbink, GJ Bock, R Bohm, A Boldizsar, L Borgia, B Bourilkov, D Bourquin, M Braccini, S Branson, JG Brigljevic, V Brock, IC Buffini, A Buijs, A Burger, JD Burger, WJ Busenitz, J Button, A Cai, XD Campanelli, M Capell, M Romeo, GC Carlino, G Cartacci, AM Casaus, J Castellini, G Cavallari, F Cavallo, N Cecchi, C Cerrada, M Cesaroni, F Chamizo, M Chang, YH Chaturvedi, UK Chekanov, SV Chemarin, M Chen, A Chen, G Chen, GM Chen, HF Chen, HS Chereau, X Chiefari, G Chien, CY Cifarelli, L Cindolo, F Civinini, C Clare, I Clare, R Cohn, HO Coignet, G Colijn, AP Colino, N Costantini, S Cotorobai, F de la Cruz, B Csilling, A Dai, TS D'Alessandro, R de Asmundis, R Degre, A Deiters, K della Volpe, D Denes, P DeNotaristefani, F DiBitonto, D Diemoz, M van Dierendonck, D Di Lodovico, F Dionisi, C Dittmar, M Dominguez, A Doria, A Dova, MT Duchesneau, D Duinker, P Duran, I Dutta, S Easo, S Efremenko, Y El Mamouni, H Engler, A Eppling, FJ Erne, FC Ernenwein, JP Extermann, P Fabre, M Faccini, R Falciano, S Favara, A Fay, J Fedin, O Felcini, M Fenyi, B Ferguson, T Ferroni, F Fesefeldt, H Fiandrini, E Field, JH Filthaut, F Fisher, PH Fisk, I Forconi, G Fredj, L Freudenreich, K Furetta, C Galaktionov, Y Ganguli, SN Garcia-Abia, P Gau, SS Gentile, S Gheordanescu, N Giagu, S Goldfarb, S Goldstein, J Gong, ZF Gougas, A Gratta, G Gruenewald, MW Gupta, VK Gurtu, A Gutay, LJ Hartmann, B Hasan, A Hatzifotiadou, D Hebbeker, T Herve, A van Hoek, WC Hofer, H Hong, SJ Hoorani, H Hou, SR Hu, G Innocente, V Jenkes, K Jin, BN Jones, LW de Jong, P Josa-Mutuberria, I Kasser, A Khan, RA Kamrad, D Kamyshkov, Y Kapustinsky, JS Karyotakis, Y Kaur, M Kienzle-Focacci, MN Kim, D Kim, DH Kim, JK Kim, SC Kim, YG Kinnison, WW Kirkby, A Kirkby, D Kirkby, J Kiss, D Kittel, W Klimentov, A Konig, AC Kopp, A Korolko, I Koutsenko, V Kraemer, RW Krenz, W Kunin, A Lacentre, P de Guevara, PL Laktineh, I Landi, G Lapoint, C Lassila-Perini, K Laurikainen, P Lebeau, M Lebedev, A Lebrun, P Lecomte, P Lecoq, P Le Coultre, P Lee, HJ Le Goff, JM Leiste, R Leonardi, E Levtchenko, P Li, C Lin, CH Lin, WT Linde, FL Lista, L Liu, ZA Lohmann, W Longo, E Lu, W Lu, YS Lubelsmeyer, K Luci, C Luckey, D Luminari, L Lustermann, W Ma, WG Maity, M Majumder, G Malgeri, L Malinin, A Mana, C Mangeol, D Mangla, S Marchesini, P Marin, A Martin, JP Marzano, F Massaro, GGG McNally, D McNeil, RR Mele, S Merola, L Meschini, M Metzger, WJ von der Mey, M Mi, Y Mihul, A van Mil, AJW Milcent, H Mirabelli, G Mnich, J Molnar, P Monteleoni, B Moore, R Morganti, S Moulik, T Mount, R Muheim, F Muijs, AJM Nahn, S Napolitano, M Nessi-Tedaldi, F Newman, H Niessen, T Nippe, A Nisati, A Nowak, H Oh, YD Opitz, H Organtini, G Ostonen, R Palomares, C Pandoulas, D Paoletti, S Paolucci, P Park, HK Park, IH Pascale, G Passaleva, G Patricelli, S Paul, T Pauluzzi, M Paus, C Pauss, F Peach, D Pei, YJ Pensotti, S Perret-Gallix, D Petersen, B Petrak, S Pevsner, A Piccolo, D Pieri, M Piroue, PA Pistolesi, E Plyaskin, V Pohl, M Pojidaev, V Postema, H Produit, N Prokofiev, D Rahal-Callot, G Raja, N Rancoita, PG Rattaggi, M Raven, G Razis, P Read, K Ren, D Rescigno, M Reucroft, S van Rhee, T Riemann, S Riles, K Robohm, A Rodin, J Roe, BP Romero, L Rosier-Lees, S Rosselet, P van Rossum, W Roth, S Rubio, JA Ruschmeier, D Rykaczewski, H Salicio, J Sanchez, E Sanders, MP Sarakinos, ME Sarkar, S Schafer, C Schegelsky, V Schmidt-Kaerst, S Schmitz, D Scholz, N Schopper, H Schotanus, DJ Schwenke, J Schwering, G Sciacca, C Sciarrino, D Servoli, L Shevchenko, S Shivarov, N Shoutko, V Shukla, J Shumilov, E Shvorob, A Siedenburg, T Son, D Smith, B Spillantini, P Steuer, M Stickland, DP Stone, A Stone, H Stoyanov, B Straessner, A Strauch, K Sudhakar, K Sultanov, G Sun, LZ Susinno, GF Suter, H Swain, JD Tang, XW Tauscher, L Taylor, L Ting, SCC Ting, SM Tonwar, SC Toth, J Tully, C Tuchscherer, H Tung, KL Uchida, Y Ulbricht, J Uwer, U Valente, E Van de Walle, RT Vesztergombi, G Vetlitsky, I Viertel, G Vivargent, M Volkert, R Vogel, H Vogt, H Vorobiev, I Vorobyov, AA Vorvolakos, A Wadhwa, M Wallraff, W Wang, JC Wang, XL Wang, ZM Weber, A Wu, SX Wynhoff, S Xu, J Xu, ZZ Yang, BZ Yang, CG Yao, XY Ye, JB Yeh, SC You, JM Zalite, A Zalite, Y Zemp, P Zeng, Y Zhang, Z Zhang, ZP Zhou, B Zhu, GY Zhu, RY Zichichi, A Ziegler, F AF Acciarri, M Adriani, O Aguilar-Benitez, M Ahlen, S Alcaraz, J Alemanni, G Allaby, J Aloisio, A Alverson, G Alviggi, MG Ambrosi, G Anderhub, H Andreev, VP Angelescu, T Anselmo, F Arefiev, A Azemoon, T Aziz, T Bagnaia, P Baksay, L Banerjee, S Banerjee, S Banicz, K Barczyk, A Barillere, R Barone, L Bartalini, P Baschirotto, A Basile, M Battiston, R Bay, A Becattini, F Becker, U Behner, F Berdugo, J Berges, P Bertucci, B Betev, BL Bhattacharya, S Biasini, M Biland, A Bilei, GM Blaising, JJ Blyth, SC Bobbink, GJ Bock, R Bohm, A Boldizsar, L Borgia, B Bourilkov, D Bourquin, M Braccini, S Branson, JG Brigljevic, V Brock, IC Buffini, A Buijs, A Burger, JD Burger, WJ Busenitz, J Button, A Cai, XD Campanelli, M Capell, M Romeo, GC Carlino, G Cartacci, AM Casaus, J Castellini, G Cavallari, F Cavallo, N Cecchi, C Cerrada, M Cesaroni, F Chamizo, M Chang, YH Chaturvedi, UK Chekanov, SV Chemarin, M Chen, A Chen, G Chen, GM Chen, HF Chen, HS Chereau, X Chiefari, G Chien, CY Cifarelli, L Cindolo, F Civinini, C Clare, I Clare, R Cohn, HO Coignet, G Colijn, AP Colino, N Costantini, S Cotorobai, F de la Cruz, B Csilling, A Dai, TS D'Alessandro, R de Asmundis, R Degre, A Deiters, K della Volpe, D Denes, P DeNotaristefani, F DiBitonto, D Diemoz, M van Dierendonck, D Di Lodovico, F Dionisi, C Dittmar, M Dominguez, A Doria, A Dova, MT Duchesneau, D Duinker, P Duran, I Dutta, S Easo, S Efremenko, Y El Mamouni, H Engler, A Eppling, FJ Erne, FC Ernenwein, JP Extermann, P Fabre, M Faccini, R Falciano, S Favara, A Fay, J Fedin, O Felcini, M Fenyi, B Ferguson, T Ferroni, F Fesefeldt, H Fiandrini, E Field, JH Filthaut, F Fisher, PH Fisk, I Forconi, G Fredj, L Freudenreich, K Furetta, C Galaktionov, Y Ganguli, SN Garcia-Abia, P Gau, SS Gentile, S Gheordanescu, N Giagu, S Goldfarb, S Goldstein, J Gong, ZF Gougas, A Gratta, G Gruenewald, MW Gupta, VK Gurtu, A Gutay, LJ Hartmann, B Hasan, A Hatzifotiadou, D Hebbeker, T Herve, A van Hoek, WC Hofer, H Hong, SJ Hoorani, H Hou, SR Hu, G Innocente, V Jenkes, K Jin, BN Jones, LW de Jong, P Josa-Mutuberria, I Kasser, A Khan, RA Kamrad, D Kamyshkov, Y Kapustinsky, JS Karyotakis, Y Kaur, M Kienzle-Focacci, MN Kim, D Kim, DH Kim, JK Kim, SC Kim, YG Kinnison, WW Kirkby, A Kirkby, D Kirkby, J Kiss, D Kittel, W Klimentov, A Konig, AC Kopp, A Korolko, I Koutsenko, V Kraemer, RW Krenz, W Kunin, A Lacentre, P de Guevara, PL Laktineh, I Landi, G Lapoint, C Lassila-Perini, K Laurikainen, P Lebeau, M Lebedev, A Lebrun, P Lecomte, P Lecoq, P Le Coultre, P Lee, HJ Le Goff, JM Leiste, R Leonardi, E Levtchenko, P Li, C Lin, CH Lin, WT Linde, FL Lista, L Liu, ZA Lohmann, W Longo, E Lu, W Lu, YS Lubelsmeyer, K Luci, C Luckey, D Luminari, L Lustermann, W Ma, WG Maity, M Majumder, G Malgeri, L Malinin, A Mana, C Mangeol, D Mangla, S Marchesini, P Marin, A Martin, JP Marzano, F Massaro, GGG McNally, D McNeil, RR Mele, S Merola, L Meschini, M Metzger, WJ von der Mey, M Mi, Y Mihul, A van Mil, AJW Milcent, H Mirabelli, G Mnich, J Molnar, P Monteleoni, B Moore, R Morganti, S Moulik, T Mount, R Muheim, F Muijs, AJM Nahn, S Napolitano, M Nessi-Tedaldi, F Newman, H Niessen, T Nippe, A Nisati, A Nowak, H Oh, YD Opitz, H Organtini, G Ostonen, R Palomares, C Pandoulas, D Paoletti, S Paolucci, P Park, HK Park, IH Pascale, G Passaleva, G Patricelli, S Paul, T Pauluzzi, M Paus, C Pauss, F Peach, D Pei, YJ Pensotti, S Perret-Gallix, D Petersen, B Petrak, S Pevsner, A Piccolo, D Pieri, M Piroue, PA Pistolesi, E Plyaskin, V Pohl, M Pojidaev, V Postema, H Produit, N Prokofiev, D Rahal-Callot, G Raja, N Rancoita, PG Rattaggi, M Raven, G Razis, P Read, K Ren, D Rescigno, M Reucroft, S van Rhee, T Riemann, S Riles, K Robohm, A Rodin, J Roe, BP Romero, L Rosier-Lees, S Rosselet, P van Rossum, W Roth, S Rubio, JA Ruschmeier, D Rykaczewski, H Salicio, J Sanchez, E Sanders, MP Sarakinos, ME Sarkar, S Schafer, C Schegelsky, V Schmidt-Kaerst, S Schmitz, D Scholz, N Schopper, H Schotanus, DJ Schwenke, J Schwering, G Sciacca, C Sciarrino, D Servoli, L Shevchenko, S Shivarov, N Shoutko, V Shukla, J Shumilov, E Shvorob, A Siedenburg, T Son, D Smith, B Spillantini, P Steuer, M Stickland, DP Stone, A Stone, H Stoyanov, B Straessner, A Strauch, K Sudhakar, K Sultanov, G Sun, LZ Susinno, GF Suter, H Swain, JD Tang, XW Tauscher, L Taylor, L Ting, SCC Ting, SM Tonwar, SC Toth, J Tully, C Tuchscherer, H Tung, KL Uchida, Y Ulbricht, J Uwer, U Valente, E Van de Walle, RT Vesztergombi, G Vetlitsky, I Viertel, G Vivargent, M Volkert, R Vogel, H Vogt, H Vorobiev, I Vorobyov, AA Vorvolakos, A Wadhwa, M Wallraff, W Wang, JC Wang, XL Wang, ZM Weber, A Wu, SX Wynhoff, S Xu, J Xu, ZZ Yang, BZ Yang, CG Yao, XY Ye, JB Yeh, SC You, JM Zalite, A Zalite, Y Zemp, P Zeng, Y Zhang, Z Zhang, ZP Zhou, B Zhu, GY Zhu, RY Zichichi, A Ziegler, F TI Search for scalar leptons, charginos and neutralinos in e(+)e(-) collisions at root s=161-172 GeV SO EUROPEAN PHYSICAL JOURNAL C LA English DT Article ID ELECTRON-POSITRON COLLISIONS; ANGLE BHABHA SCATTERING; STATE QED CORRECTIONS; W-PAIR PRODUCTION; MONTE-CARLO; L3 EXPERIMENT; SUPERSYMMETRIC PARTICLES; P(P)OVER-BAR COLLISIONS; E+E COLLISIONS; CROSS-SECTIONS AB Scalar leptons, charginos and neutralinos, predicted by supersymmetric theories, have been searched for in data samples collected with the L3 detector at centre-of-mass energies of 161 GeV and 172 GeV with integrated luminosities of 10.7 pb(-1) and 10.0 pb(-1) respectively. No evidence for such particles is found. New limits on production cross sections are set, assuming R-parity conservation. New exclusion contours in the Minimal Supersymmetric Standard Mc del parameter space as well as new lower limits on masses are derived. C1 Rhein Westfal TH Aachen, Inst Phys 1, D-52056 Aachen, Germany. Rhein Westfal TH Aachen, Inst Phys 3, D-52056 Aachen, Germany. NIKHEF, Natl Inst High Energy Phys, NL-1009 DB Amsterdam, Netherlands. Univ Amsterdam, NL-1009 DB Amsterdam, Netherlands. Univ Michigan, Ann Arbor, MI 48109 USA. CNRS, LAPP, IN2P3, Lab Annecy Le Vieux Phys Particules, F-74941 Annecy Le Vieux, France. Johns Hopkins Univ, Baltimore, MD 21218 USA. Univ Basel, Inst Phys, CH-4056 Basel, Switzerland. Louisiana State Univ, Baton Rouge, LA 70803 USA. Inst High Energy Phys, Beijing 100039, Peoples R China. Humboldt Univ, D-10099 Berlin, Germany. Univ Bologna, I-40126 Bologna, Italy. Ist Nazl Fis Nucl, Sez Bologna, I-40126 Bologna, Italy. Tata Inst Fundamental Res, Bombay 400005, Maharashtra, India. Boston Univ, Boston, MA 02215 USA. Northeastern Univ, Boston, MA 02115 USA. Inst Atom Phys, R-76900 Bucharest, Romania. Univ Bucharest, R-76900 Bucharest, Romania. Hungarian Acad Sci, Cent Res Inst Phys, H-1525 Budapest 114, Hungary. Harvard Univ, Cambridge, MA 02139 USA. MIT, Cambridge, MA 02139 USA. Ist Nazl Fis Nucl, Sez Firenze, I-50125 Florence, Italy. Univ Florence, I-50125 Florence, Italy. CERN, European Lab Particle Phys, CH-1211 Geneva 23, Switzerland. FBLJA, World Lab, CH-1211 Geneva 23, Switzerland. Univ Geneva, CH-1211 Geneva 4, Switzerland. Univ Sci & Technol China, USTC, Hefei 230029, Anhui, Peoples R China. SEFT, Res Inst High Energy Phys, SF-00014 Helsinki, Finland. Univ Lausanne, CH-1015 Lausanne, Switzerland. Ist Nazl Fis Nucl, Sez Lecce, I-73100 Lecce, Italy. Univ Lecce, I-73100 Lecce, Italy. Los Alamos Natl Lab, Los Alamos, NM 87544 USA. Univ Lyon 1, CNRS, IN2P3, Inst Phys Nucl, F-69622 Villeurbanne, France. CIEMAT, Ctr Invest Energet Medioambientales & Tecnol, E-28040 Madrid, Spain. Ist Nazl Fis Nucl, Sez Milano, I-20133 Milan, Italy. ITEP, Inst Theoret & Expt Phys, Moscow, Russia. Ist Nazl Fis Nucl, Sez Napoli, I-80125 Naples, Italy. Univ Naples Federico II, I-80125 Naples, Italy. Univ Cyprus, Dept Nat Sci, Nicosia, Cyprus. Univ Nijmegen, NL-6525 ED Nijmegen, Netherlands. Natl Inst Nucl Phys & High Energy Phys, NL-6525 ED Nijmegen, Netherlands. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. CALTECH, Pasadena, CA 91125 USA. Ist Nazl Fis Nucl, Sez Perugia, I-06100 Perugia, Italy. Univ Perugia, I-06100 Perugia, Italy. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Princeton Univ, Princeton, NJ 08544 USA. Ist Nazl Fis Nucl, Sez Roma, I-00185 Rome, Italy. Univ Roma La Sapienza, I-00185 Rome, Italy. Inst Nucl Phys, St Petersburg, Russia. Univ Salerno, I-84100 Salerno, Italy. Ist Nazl Fis Nucl, I-84100 Salerno, Italy. Univ Calif San Diego, San Diego, CA 92093 USA. Univ Santiago, Dept Fis Particulas Elementales, E-15706 Santiago De Compostela, Spain. Bulgarian Acad Sci, Cent Lab Mechatron & Instrumentat, BU-1113 Sofia, Bulgaria. Korea Adv Inst Sci & Technol, Ctr High Energy Phys, Taejon 305701, South Korea. Univ Alabama, Tuscaloosa, AL 35486 USA. Univ Utrecht, NL-3584 CB Utrecht, Netherlands. NIKHEF, NL-3584 CB Utrecht, Netherlands. Purdue Univ, W Lafayette, IN 47907 USA. Paul Scherrer Inst, CH-5232 Villigen, Switzerland. DESY, Inst Hochenergiephys, D-15738 Zeuthen, Germany. Swiss Fed Inst Technol, CH-8093 Zurich, Switzerland. RP Rhein Westfal TH Aachen, Inst Phys 1, D-52056 Aachen, Germany. RI Duran, Ignacio/H-7254-2015; Sanchez, Eusebio/H-5228-2015; Rancoita, Pier Giorgio/J-9896-2015; Hoorani, Hafeez/D-1791-2013; Palomares, Carmen/H-7783-2015; Fedin, Oleg/H-6753-2016; Roth, Stefan/J-2757-2016; Kamyshkov, Yuri/J-7999-2016; Di Lodovico, Francesca/L-9109-2016; Fiandrini, Emanuele/C-4549-2008; Lista, Luca/C-5719-2008; Kirkby, Jasper/A-4973-2012; Servoli, Leonello/E-6766-2012; bertucci, bruna/J-5237-2012; Cavallo, Nicola/F-8913-2012; Cerrada, Marcos/J-6934-2014; de la Cruz, Begona/K-7552-2014; Josa, Isabel/K-5184-2014; Vogel, Helmut/N-8882-2014; Ferguson, Thomas/O-3444-2014; Berdugo, Javier/A-2858-2015; D'Alessandro, Raffaello/F-5897-2015 OI Sanchez, Eusebio/0000-0002-9646-8198; Rancoita, Pier Giorgio/0000-0002-1990-4283; Palomares, Carmen/0000-0003-4374-9065; Roth, Stefan/0000-0003-3616-2223; Kamyshkov, Yuri/0000-0002-3789-7152; Di Lodovico, Francesca/0000-0003-3952-2175; Castellini, Guido/0000-0002-0177-0643; Kirkby, Jasper/0000-0003-2341-9069; Servoli, Leonello/0000-0003-1725-9185; Cerrada, Marcos/0000-0003-0112-1691; Vogel, Helmut/0000-0002-6109-3023; Ferguson, Thomas/0000-0001-5822-3731; Berdugo, Javier/0000-0002-7911-8532; D'Alessandro, Raffaello/0000-0001-7997-0306 NR 58 TC 24 Z9 24 U1 0 U2 7 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 JUN PY 1998 VL 4 IS 2 BP 207 EP 219 DI 10.1007/s100520050198 PG 13 WC Physics, Particles & Fields SC Physics GA 104RG UT WOS:000075027100003 ER PT J AU Agakichiev, G Appenheimer, M Averbeck, R Ballester, F Baur, R Brenschede, A Diaz, J Drees, A Faschingbauer, U Ferrero, JL Fischer, P Fraenkel, Z Franke, M Fuchs, C Gatti, E Glassel, P Gunzel, T de los Heros, CP Hess, F Holzmann, R Iourevitch, V Irmscher, D Jacob, C Kuhn, W Lenkeit, B Lohner, H Marin, A Marques, FM Martinez, G Metag, V Notheisen, M Novotny, R Olsen, LH Ostendorf, R Panebrattsev, Y Pfeiffer, A Ravinovich, I Rehak, P Sampietro, M Schon, A Schukraft, J Schutz, Y Shimansky, S Shor, A Simon, RS Specht, HJ Steiner, V Tapprogge, S Tel-Zur, G Tserruya, I Ullrich, T Wilschut, H Wurm, JP AF Agakichiev, G Appenheimer, M Averbeck, R Ballester, F Baur, R Brenschede, A Diaz, J Drees, A Faschingbauer, U Ferrero, JL Fischer, P Fraenkel, Z Franke, M Fuchs, C Gatti, E Glassel, P Gunzel, T de los Heros, CP Hess, F Holzmann, R Iourevitch, V Irmscher, D Jacob, C Kuhn, W Lenkeit, B Lohner, H Marin, A Marques, FM Martinez, G Metag, V Notheisen, M Novotny, R Olsen, LH Ostendorf, R Panebrattsev, Y Pfeiffer, A Ravinovich, I Rehak, P Sampietro, M Schon, A Schukraft, J Schutz, Y Shimansky, S Shor, A Simon, RS Specht, HJ Steiner, V Tapprogge, S Tel-Zur, G Tserruya, I Ullrich, T Wilschut, H Wurm, JP TI Systematic study of low-mass electron pair production in p-Be and p-Au collisions at 450 GeV/c SO EUROPEAN PHYSICAL JOURNAL C LA English DT Article ID DIRECT LEPTON PRODUCTION; D-MESON PRODUCTION; NUCLEUS COLLISIONS; PROTON-NUCLEUS; DEPENDENCE; PHYSICS; MODEL AB In a joint effort the CERES/NA45 and TAPS collaborations have measured low-mass electron pairs in p-Be and p-Au collisions at 450 GeV/c at the CERN SPS. In the range covered up to approximate to 1.5 GeV/c(2) the mass spectra from p-Be and p-Au collisions are well explained by electron pairs from decays of neutral mesons. For p-Au our result is new. For p-Be, the simultaneously measured electron pairs and photons served as a direct measure of the eta Dalitz decay contribution to the inclusive pair spectrum in which instrumental uncertainties are highly reduced. We confirm the earlier finding of HELIOS-1 with significantly reduced systematic uncertainties of 23% in the mass:range below 450 MeV/c(2), and of 28% in the mass range above 750 MeV/c(2) at 90% confidence limit. Any unconventional source of electron pairs is limited by these error margins as the percentage fraction of the hadronic contribution. C1 Max Planck Inst Kernphys, D-69117 Heidelberg, Germany. Univ Giessen, Inst Phys 2, D-35392 Giessen, Germany. GSI Darmstadt, D-64220 Darmstadt, Germany. Inst Fis Corpuscular, E-46100 Burjassot, Valencia, Spain. Univ Heidelberg, Inst Phys, D-69120 Heidelberg, Germany. Weizmann Inst Sci, IL-76100 Rehovot, Israel. Politecn Milan, I-20133 Milan, Italy. CERN, CH-1211 Geneva 23, Switzerland. Kernfys Versneller Inst, NL-9747 AA Groningen, Netherlands. GANIL, F-14021 Caen, France. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Agakichiev, G (reprint author), Max Planck Inst Kernphys, D-69117 Heidelberg, Germany. RI Diaz, Jose/B-3454-2012; Lohner, Herbert/B-2397-2014; Sampietro, Marco/A-3732-2016; Ballester, Facundo/F-5413-2016; OI Diaz, Jose/0000-0002-7239-223X; Lohner, Herbert/0000-0002-7441-739X; Sampietro, Marco/0000-0003-4825-9612; Ballester, Facundo/0000-0002-3785-8399; Perez de los Heros, Carlos/0000-0002-2084-5866 NR 42 TC 65 Z9 66 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1434-6044 J9 EUR PHYS J C JI Eur. Phys. J. C PD JUN PY 1998 VL 4 IS 2 BP 231 EP 247 DI 10.1007/s100530050204 PG 17 WC Physics, Particles & Fields SC Physics GA 104RG UT WOS:000075027100005 ER PT J AU Agakichiev, G Appenheimer, M Averbeck, R Ballester, F Baur, R Brenschede, A Diaz, J Drees, A Faschingbauer, U Ferrero, JL Fischer, P Fraenkel, Z Franke, M Fuchs, C Gatti, E Glassel, P Gunzel, T de los Hero, CP Hess, F Holzmann, R Irmscher, D Jacob, C Kuhn, W Lenkeit, B Lohner, H Marin, A Marques, FM Martinez, G Metag, V Notheisen, M Novotny, R Olsen, LH Schon, A Schukraft, J Ostendorf, R Panebrattsev, Y Pfeiffer, A Ravinovich, I Rehak, P Sampietro, M Schutz, Y Shimansky, S Shor, A Simon, RS Specht, HJ Steiner, V Tapprogge, S Tel-Zur, G Tserruya, I Ullrich, T Wilschut, H Wurm, JP Yurevich, V AF Agakichiev, G Appenheimer, M Averbeck, R Ballester, F Baur, R Brenschede, A Diaz, J Drees, A Faschingbauer, U Ferrero, JL Fischer, P Fraenkel, Z Franke, M Fuchs, C Gatti, E Glassel, P Gunzel, T de los Hero, CP Hess, F Holzmann, R Irmscher, D Jacob, C Kuhn, W Lenkeit, B Lohner, H Marin, A Marques, FM Martinez, G Metag, V Notheisen, M Novotny, R Olsen, LH Schon, A Schukraft, J Ostendorf, R Panebrattsev, Y Pfeiffer, A Ravinovich, I Rehak, P Sampietro, M Schutz, Y Shimansky, S Shor, A Simon, RS Specht, HJ Steiner, V Tapprogge, S Tel-Zur, G Tserruya, I Ullrich, T Wilschut, H Wurm, JP Yurevich, V TI Neutral meson production in p-Be and p-Au collisions at 450 GeV beam energy SO EUROPEAN PHYSICAL JOURNAL C LA English DT Article ID ELECTRON-PAIR PRODUCTION; TRANSVERSE-MOMENTUM; PARTICLE PRODUCTION; NUCLEUS COLLISIONS; HADRONS; LEPTON; PI+/; TAPS; ISR AB In a joint experiment the TAPS and CERES collaborations have studied the production of the neutral mesons pi degrees; eta and omega in 450 GeV p-Be and p-Au collisions at the CERN SPS. The mesons were identified by their pi degrees --> gamma gamma, eta --> gamma gamma, and omega --> pi degrees gamma decay modes. The cross sections were measured down to very low p(T) (greater than or equal to 20 MeV/c) near mid-rapidity (3.0 <: y < 4.0). The eta and omega, cross sections are smaller than expected from extrapolations of earlier. data to low p(T). Integrated over all p(T), the ratios eta/pi degrees and omega/pi degrees are lower by about 25% compared to previously published values. The reduction may be attributed to the large number of low pr pions from decays of heavier mesons. In addition, we have studied the dependence of neutral meson production on the mass of the nuclear target and find it in good agreement with previous measurements of charged mesons. C1 Max Planck Inst Kernphys, D-69117 Heidelberg, Germany. Univ Giessen, Inst Phys 2, D-35392 Giessen, Germany. GSI Darmstadt, D-64220 Darmstadt, Germany. Inst Fis Corpuscular, E-46100 Burjassot, Valencia, Spain. Univ Heidelberg, Inst Phys, D-69120 Heidelberg, Germany. Weizmann Inst Sci, IL-76100 Rehovot, Israel. Politecn Milan, I-20133 Milan, Italy. Kernfys Versneller Inst, NL-9747 AA Groningen, Netherlands. GANIL, F-14021 Caen, France. Brookhaven Natl Lab, Upton, NY 11973 USA. CERN, CH-1211 Geneva 23, Switzerland. RP Agakichiev, G (reprint author), Max Planck Inst Kernphys, D-69117 Heidelberg, Germany. RI Diaz, Jose/B-3454-2012; Lohner, Herbert/B-2397-2014; Sampietro, Marco/A-3732-2016; Ballester, Facundo/F-5413-2016; OI Diaz, Jose/0000-0002-7239-223X; Lohner, Herbert/0000-0002-7441-739X; Sampietro, Marco/0000-0003-4825-9612; Ballester, Facundo/0000-0002-3785-8399; Perez de los Heros, Carlos/0000-0002-2084-5866 NR 30 TC 21 Z9 21 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1434-6044 J9 EUR PHYS J C JI Eur. Phys. J. C PD JUN PY 1998 VL 4 IS 2 BP 249 EP 257 DI 10.1007/s100529800804 PG 9 WC Physics, Particles & Fields SC Physics GA 104RG UT WOS:000075027100006 ER PT J AU LaGattuta, KJ AF LaGattuta, KJ TI Multiple ionization of helium clusters by long wavelength laser radiation SO EUROPEAN PHYSICAL JOURNAL D LA English DT Article ID NONSEQUENTIAL DOUBLE-IONIZATION; FIELD; ATOMS AB We applied the method known as Fermion Molecular Dynamics to the description of a small cluster of helium atoms interacting with a short pulse of intense, long wavelength laser radiation, for both linear and circular polarization. We discuss the results of these calculations, elucidating questions relating to the mechanisms of multiple ionization in small clusters. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP LaGattuta, KJ (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 19 TC 7 Z9 7 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1434-6060 J9 EUR PHYS J D JI Eur. Phys. J. D PD JUN PY 1998 VL 2 IS 3 BP 267 EP 272 DI 10.1007/s100530050139 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 107UV UT WOS:000075230100011 ER PT J AU Koretsky, GM Knickelbein, MB AF Koretsky, GM Knickelbein, MB TI The evolution of electronic structure in lanthanide metal clusters: Threshold photoionization spectra of Ce-n and Pr-n SO EUROPEAN PHYSICAL JOURNAL D LA English DT Article ID IONIZATION-POTENTIALS; RARE-EARTH; VALENCE CHANGE; SM CLUSTERS; SIZE; TRANSITION; PARTICLES AB The photoionization spectra of Pr-2-Pr-21 and Ce-2-Ce-17 have been measured near threshold. The ionization potentials (IPs) of Pr-n and Ce-n vary discontinuously with size, but trend downward toward the work function of the bulk metals. In general, the IPs of cerium clusters display more variation than those of praseodymium clusters. The sudden discontinuities observed in the IPs of both Ce-n and Pr-n is akin to that displayed by clusters of transition metal atoms, suggesting that as in transition metal clusters, the rapid evolution in geometric structure with size is the source of these discontinuities. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Koretsky, GM (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 24 TC 17 Z9 17 U1 1 U2 4 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1434-6060 J9 EUR PHYS J D JI Eur. Phys. J. D PD JUN PY 1998 VL 2 IS 3 BP 273 EP 278 DI 10.1007/s100530050140 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 107UV UT WOS:000075230100012 ER PT J AU Baker, MC Bonazza, R AF Baker, MC Bonazza, R TI Visualization and measurements of void fraction in a gas-molten tin multiphase system by X-ray absorption SO EXPERIMENTS IN FLUIDS LA English DT Article ID NEUTRON RADIOGRAPHY; LIQUIDS; FLOW AB A technique has been developed to measure void fraction using X-rays in a 10 cm thick pool of molten tin with gas injection at various flow rates. Visualization of the multiphase mixture using high energy X-rays can be performed at imaging rates of 220 fps with 256 X 256 pixel resolution or at 30 fps with 480 X 1128 pixel resolution. The images are subsequently processed to obtain two dimensional distributions of the chordal average void fraction in the mixture. The estimated relative uncertainty of the measurement is discussed in detail and shown to be of the order of 10% of the reported value. C1 Univ Wisconsin, Dept Engn Phys, Madison, WI 53706 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Baker, MC (reprint author), Univ Wisconsin, Dept Engn Phys, 1500 Engn Dr, Madison, WI 53706 USA. NR 14 TC 12 Z9 12 U1 0 U2 2 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 JUN PY 1998 VL 25 IS 1 BP 61 EP 68 DI 10.1007/s003480050208 PG 8 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA ZW498 UT WOS:000074417000007 ER PT J AU Wohl, DL McArthur, JV AF Wohl, DL McArthur, JV TI Actinomycete-flora associated with submersed freshwater macrophytes SO FEMS MICROBIOLOGY ECOLOGY LA English DT Article DE actinomycete; freshwater macrophyte; stream; selective medium; isolation technique ID DIVERSITY; WATER AB Aquatic vegetation from three stream sites located within the US Department of Energy's Savannah River Site, South Carolina was sampled to determine the presence, distribution and diversity of actinomycetes on submersed macrophytes. At individual sampling sites, small pieces of submersed aquatic plants (Sparganium americanum, Ranunculus pusillus and Microanthemum umbrosum) were clipped and placed in sterile sampling containers. In the laboratory, plant fragments were subjected to a wide array of selective measures (5 pretreatments x 8 media X 2 antibiotic regimes x 2 temperatures) in order to obtain the greatest diversity and best isolation methods. A total of 433 actinomycete colonies was isolated, which included 32 distinct strains. The streams, plants and plant tissue types (healthy, necrotic or dead) all had an effect on the presence, distribution and diversity of the actinomycetes. (C) 1998 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved. C1 Savannah River Ecol Lab, Aiken, SC 29802 USA. RP Wohl, DL (reprint author), Savannah River Ecol Lab, Drawer E, Aiken, SC 29802 USA. EM wohl@srel.edu NR 23 TC 23 Z9 23 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-6496 J9 FEMS MICROBIOL ECOL JI FEMS Microbiol. Ecol. PD JUN PY 1998 VL 26 IS 2 BP 135 EP 140 DI 10.1111/j.1574-6941.1998.tb00499.x PG 6 WC Microbiology SC Microbiology GA ZV467 UT WOS:000074307500006 ER PT J AU Ramsey, MJ Nagao, M Inoue, R Fujita, H Matsushima, T Tucker, JD AF Ramsey, MJ Nagao, M Inoue, R Fujita, H Matsushima, T Tucker, JD TI Chromosome aberrations induced in mice by chronic feeding of 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ) SO FOOD AND CHEMICAL TOXICOLOGY LA English DT Article ID COOKED-FOOD MUTAGENS; RADIATION IN-VITRO; FRIED GROUND-BEEF; HETEROCYCLIC AMINES; BIOLOGICAL SIGNIFICANCE; CANCER; DNA; IDENTIFICATION; LYMPHOCYTES; MOUSE AB Dietary intake of mutagenic compounds is considered to be an important factor for the induction of some human cancers. Highly mutagenic compounds are known to be formed in meat during the cooking process. Since the discovery of such compounds, many studies have been conducted to evaluate their carcinogenic potential. One of the most mutagenic compounds formed in the cooking of meat is 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ). The recent development of mouse chromosome painting probes expand the capability of evaluating these food mutagens as potential clastogens in vivo. In this paper, we demonstrate the induction of chromosome aberrations in mice chronically exposed to MeIQ in their diet. CDF1 female mice were fed 400 ppm MeIQ beginning at 7 wk of age. At 76 wk of age, five control and eight exposed mice were euthanized. Blood and bone marrow cells were obtained and arrested in metaphase. Whole chromosome painting probes were used for fluorescence its situ hybridization of metaphase cells from blood and bone marrow. MeIQ-exposed mice were found to have a twofold increase in translocations and a 16-fold increase in fragments in their peripheral blood compared with controls. No aberrations were observed in the bone marrow. All organs were examined for the presence of tumours and routine histopathological analysis was performed on all organs as well as any tissue with macroscopic ab;normalities. Forestomach and/or liver tumours developed in all but one of the mice fed MeIQ, but no such tumours were observed in the control mice. These data indicate that MeIQ is clastogenic and carcinogenic in vivo. (C) 1998 Published by Elsevier Science Ltd. All rights reserved. C1 Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94551 USA. Natl Canc Ctr, Res Inst, Div Carcinogenesis, Chuo Ku, Tokyo 104, Japan. Japan Bioassay Lab, Kanagawa 257, Japan. RP Tucker, JD (reprint author), Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, POB 808 L-452, Livermore, CA 94551 USA. FU NCI NIH HHS [CA55861] NR 55 TC 7 Z9 7 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0278-6915 J9 FOOD CHEM TOXICOL JI Food Chem. Toxicol. PD JUN PY 1998 VL 36 IS 6 BP 467 EP 474 DI 10.1016/S0278-6915(98)00003-9 PG 8 WC Food Science & Technology; Toxicology SC Food Science & Technology; Toxicology GA ZX604 UT WOS:000074534900002 PM 9674954 ER PT J AU Foster, I von Laszewski, G Thiruvathukal, GK Toonen, B AF Foster, I von Laszewski, G Thiruvathukal, GK Toonen, B TI A computational framework for telemedicine SO FUTURE GENERATION COMPUTER SYSTEMS-THE INTERNATIONAL JOURNAL OF GRID COMPUTING AND ESCIENCE LA English DT Article DE Globus toolkit; telemedicine; metacomputing AB Emerging telemedicine applications require the ability to exploit diverse and geographically distributed resources. Highspeed networks are used to integrate advanced visualization devices, sophisticated instruments, large databases, archival storage devices, PCs, workstations, and supercomputers. This form of telemedical environment is similar to networked virtual supercomputers, also known as metacomputers. Metacomputers are already being used in many scientific application areas. In this article, we analyze requirements necessary for a telemedical computing infrastructure and compare them with requirements found in a typical metacomputing environment. We will show that metacomputing environments can be used to enable a more powerful and unified computational infrastructure for telemedicine. The Globus metacomputing toolkit can provide the necessary low level mechanisms to enable a large scale telemedical infrastructure. The Globus toolkit components are designed in a modular fashion and can be extended to support the specific requirements for telemedicine. (C) 1998 Elsevier Science B.V. C1 Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. RP von Laszewski, G (reprint author), Argonne Natl Lab, Div Math & Comp Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. EM foster@mcs.anl.gov; gregor@mcs.anl.gov; thiruvat@mcs.anl.gov; toonen@mcs.anl.gov RI von Laszewski, Gregor/C-2808-2012 OI von Laszewski, Gregor/0000-0001-9558-179X NR 25 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-739X EI 1872-7115 J9 FUTURE GENER COMP SY JI Futur. Gener. Comp. Syst. PD JUN PY 1998 VL 14 IS 1-2 BP 109 EP 123 DI 10.1016/S0167-739X(98)00013-2 PG 15 WC Computer Science, Theory & Methods SC Computer Science GA ZX113 UT WOS:000074480700010 ER PT J AU Kohn, MJ Valley, JW AF Kohn, MJ Valley, JW TI Oxygen isotope geochemistry of the amphiboles: Isotope effects of cation substitutions in minerals SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID CENTRAL NEW-HAMPSHIRE; POST POND VOLCANICS; TIERRA-DEL-FUEGO; P-T PATHS; CLOSURE TEMPERATURES; STRUCTURAL EVOLUTION; METAMORPHIC ROCKS; CORDILLERA DARWIN; PHASE-EQUILIBRIA; METABASIC ROCKS AB The occurrence of coexisting amphiboles in rocks and the likelihood of concurrent isotope closure allows equilibrium oxygen isotope fractionations among the amphiboles to be recovered from natural samples. Oxygen isotope analyses of mineral separates using laser fluorination show that coexisting amphiboles increasingly partition O-18 in the order: hornblende much less than gedrite < cummingtonite less than or equal to anthophyllite. The observed fractionations at similar to 575 degrees C are: Delta(Ged-Hbl) = 0.8 parts per thousand, Delta(Cum-Hbl) = 0.9, Delta(Cum-Ged) = 0.2, Delta(Ath-Ged) = 0.3, and Delta(Ath-Hbl) > 0.9. Previously published data for hornblende, actinolite, glaucophane, and garnet show that Delta(Act-Hbl) similar to 0.2, Delta(Gln-Grt) much greater than 1, and Delta(Hbl-Crt) similar to 0. Thus, glaucophane strongly partitions O-18 relative to the calcic amphiboles. The fractionation between two amphiboles of arbitrary composition can be predicted from the known fractionations for mica endmembers, pyroxene endmembers, acid exchange components such as CaAl(NaSi)(-1), NaAl(CaMg)(-1), CaMg-1, MgFe-1, FeMn-1, KNa-1, KAl(Si)(-1), and Fe3+ Al-1. Applications of the exchange component method reproduce measured amphibole fractionations to within +/-0.1 to +/-0.2 parts per thousand, whereas other predictive methods cause misfit for typical metamorphic hornblende of greater than or equal to 0.5 parts per thousand at 575 degrees C. Although the isotope effects of cation exchanges may be small at high-T, they magnify dramatically for minerals formed in surficial, diagenetic, and low-T metamorphic environments. Different composition clays are predicted to have equilibrium delta(18)O differences of 2-9 parts per thousand. If the: isotope fractionation can be determined for one mineral endmember, then calibrated exchanges allow accurate prediction of the isotope fractionations for intermediate compositions of most ortho-, ring-, chain-, and sheet-silicates. Copyright (C) 1998 Elsevier Science Ltd. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Wisconsin, Dept Geol & Geophys, Madison, WI 53706 USA. RP Kohn, MJ (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RI Valley, John/B-3466-2011; Kohn, Matthew/A-2562-2012 OI Valley, John/0000-0003-3530-2722; NR 64 TC 27 Z9 28 U1 0 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUN PY 1998 VL 62 IS 11 BP 1947 EP 1958 DI 10.1016/S0016-7037(98)00117-3 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 104HR UT WOS:000075009100010 ER PT J AU Richter, FM Liang, Y Minarik, WG AF Richter, FM Liang, Y Minarik, WG TI Multicomponent diffusion and convection in molten MgO-Al2O3-SiO2 SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID SILICATE MELTS AB Multicomponent diffusion and convection in molten MgO-Al2O3-SiO2 at 1550 degrees C and 0.5 GPa were examined experimentally in diffusion couples formed around 22.5 (wt%) MgO, 17.5% Al2O3, and 60% SiO2. The diffusion matrix obtained from a simultaneous least squares inversion of convectively stable intersecting chemical diffusion profiles has large off-diagonal terms indicating, for example, very strong coupling of the flux of SiO2 with gradients in MgO. In contrast to an earlier report on multicomponent diffusion involving the same compositions studied here, we found no features along the stable diffusion profiles that could not be explained in terms of a 2 x 2 diffusion matrix. X-ray concentration maps of the sectioned diffusion charges showed that double-diffusive convection had occurred in a number of experiments along the direction of constant SiO2, even though the more dense melt had been placed below the less dense composition. The occurrence of such double-diffusive fingering instabilities is shown to be consistent with the predictions of linear stability theory. Copyright (C) 1998 Elsevier Science Ltd. C1 Univ Chicago, Dept Geophys Sci, Chicago, IL 60637 USA. Rensselaer Polytech Inst, Dept Earth & Environm Sci, Troy, NY 12180 USA. Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94551 USA. RP Richter, FM (reprint author), Univ Chicago, Dept Geophys Sci, 5734 S Ellis Ave, Chicago, IL 60637 USA. EM richter@geosci.uchicago.edu RI Minarik, William/F-5590-2013; Liang, Yan/G-2241-2016 OI Minarik, William/0000-0001-5509-5543; Liang, Yan/0000-0002-9569-840X NR 17 TC 16 Z9 16 U1 4 U2 10 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 JUN PY 1998 VL 62 IS 11 BP 1985 EP 1991 DI 10.1016/S0016-7037(98)00123-9 PG 7 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 104HR UT WOS:000075009100013 ER PT J AU Brenan, JM Neroda, E Lundstrom, CC Shaw, HF Ryerson, FJ Phinney, DL AF Brenan, JM Neroda, E Lundstrom, CC Shaw, HF Ryerson, FJ Phinney, DL TI Behaviour of boron, beryllium, and lithium during melting and crystallization: Constraints from mineral-melt partitioning experiments SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID YOUNG VOLCANIC-ROCKS; UPPER-MANTLE; TRACE-ELEMENTS; ION-MICROPROBE; ARC MAGMAS; SYSTEMATICS; SPINEL; ORIGIN; ISLAND; LAVAS AB In order to provide a mon substantial foundation for interpreting the behaviour of B, Be, and Li during the production and early crystallization of primitive igneous rocks, we have measured olivine-, clinopyroxene-, orthopyroxene-, and amphibole-melt partition coefficients for these elements involving broadly basaltic-andesitic melt compositions. Experiments were conducted at both one atmosphere and 1.0-1.5 GPa and employed a time-temperature history that yielded large crystals with minimal compositional zoning. Experiment temperatures ranged from 1000 to 1350 degrees C and were selected to minimize the total crystal fraction in a given experiment. Partition coefficients for olivine and clinopyroxene were found to be independent of run duration or total concentration of B, Be, or Li suggesting that crystal-liquid equilibrium was closely approached. Olivine-, orthopyroxene-, and clinopyroxene-melt partition coefficients decrease in the order: Li (0.1-0.2) much greater than Be similar to B (0.002-0.03), whereas amphibole-melt partition coefficients for Be and Li are similar (similar to 0.2) and larger than those for B (similar to 0.02). Comparison of partition coefficients measured in this study with previous determinations yields good agreement, with the exception of some of our mineral-melt values for B, which are uniformly lower (up to 10 times) than values determined at similar conditions of pressure and temperature. The latter discrepancy could be due to mineral or melt compositional effects, but this hypothesis is currently untestable owing to the absence of reported mineral compositions in previous studies. Partition coefficients for olivine and clinopyroxene have been found to vary as a function of mineral and melt composition, and with the exception of B partitioning into clinopyroxene, this variation can be modeled using simple exchange reactions involving the trace element and a substituent element, such as Na, Mg, or Al. Partition coefficients measured in this study were combined with simple models of melting and crystallization to evaluate how accurately element ratios such as B/Be, B/K, B/Nb, Be/Nd, Li/V, and Li/Yb in primitive magmas reflect that of their source. These models further confirm that the source regions of IAB magmas are enriched in B/Be, B/Nb, and Li/Yb relative to the MORE source, thus lending further support to the notion of metasomatic enrichment of the IAB sourer by slab-derived fluids. Moreover, our modeling also indicates that the low B/Be and B/Nb in primitive OIB magmas is indicative of similarly low values in OIB sources, which is consistent with the hypothesis that OIB sources contain a B-depleted component, such as subducted, dehydrated oceanic crust. Partial melting models have also been constructed to explore the possibility of using the LIN ratio in MORE and IAB as a monitor of redox conditions in their source-regions. Models indicate that this ratio does not uniquely constrain source fO(2) without a priori knowledge of the degree of melting. However, the small amount of dispersion in MORE Li/V is consistent with (1) the small variation in source-region fO(2) inferred for MORE by independent means and (2) degrees of melting close to clinopyroxene exhaustion. The very large dispersion in Li/V ratios in the IAB suite can be reconciled by melt generation under more oxidising conditions than that for MORE, in addition to variation in source composition resulting from metasomatism involving a Li-rich component. Copyright (C) 1998 Elsevier Science Ltd. C1 Univ Toronto, Dept Geol, Toronto, ON M5S 3B1, Canada. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Univ Calif Santa Cruz, Earth Sci Board, Santa Cruz, CA 95064 USA. Univ Calif Lawrence Livermore Natl Lab, Geosci & Environm Technol Div, Livermore, CA 94551 USA. Univ Calif Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94551 USA. Univ Calif Lawrence Livermore Natl Lab, Div Nucl Chem, Livermore, CA 94551 USA. RP Brenan, JM (reprint author), Univ Toronto, Dept Geol, Toronto, ON M5S 3B1, Canada. RI Shaw, Henry/B-6445-2012 OI Shaw, Henry/0000-0003-0681-5430 NR 49 TC 160 Z9 168 U1 5 U2 34 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUN PY 1998 VL 62 IS 12 BP 2129 EP 2141 DI 10.1016/S0016-7037(98)00131-8 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 109JA UT WOS:000075317300008 ER PT J AU Burnham, AK AF Burnham, AK TI Comment on "Experiments on the role of water in petroleum formation" by M.D. Lewan SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Editorial Material ID HYDROCARBON GENERATION; HYDROUS PYROLYSIS; KINETIC-MODEL; SOURCE ROCKS; EXPULSION; KEROGEN; OIL; DESTRUCTION; BASIN C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Burnham, AK (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NR 21 TC 13 Z9 13 U1 1 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUN PY 1998 VL 62 IS 12 BP 2207 EP 2210 PG 4 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 109JA UT WOS:000075317300017 ER PT J AU Goff, F Janik, CJ Delgado, H Werner, C Counce, D Stimac, JA Siebe, C Love, SP Williams, SN Fischer, T Johnson, L AF Goff, F Janik, CJ Delgado, H Werner, C Counce, D Stimac, JA Siebe, C Love, SP Williams, SN Fischer, T Johnson, L TI Geochemical surveillance of magmatic volatiles at Popocatepetl volcano, Mexico SO GEOLOGICAL SOCIETY OF AMERICA BULLETIN LA English DT Article ID MOUNT ST-HELENS; IZTACCIHUATL VOLCANO; HYDROTHERMAL SYSTEM; YOUNGER ANDESITES; BASALTIC MAGMA; INCLUSIONS; CALIFORNIA; EMISSIONS; PETROLOGY; DIOXIDE AB Surveillance of Popocatepetl volcanic plume geochemistry and SO2 flux began in early 1994 after fumarolic and seismic activity increased significantly during 1993, Volatile traps placed around the summit were collected at near-monthly intervals until the volcano erupted on December 21, 1994, Additional trap samples were obtained in early 1996 before the volcano erupted again, emplacing a small dacite dome in the summit crater. Abundances of volatile constituents (ppm/day of CL, S-total, F, CO2, Hg, and As) varied, but most constituents were relatively high in early and late 1994, However, ratios of these constituents to Cl were highest in mid-1994, delta(34)S-S-total in trap solutions ranged from 1.5 parts per thousand to 6.4 parts per thousand; lowest values generally occurred during late 1994, delta(13)C-CO2 of trap solutions were greatly contaminated with atmospheric CO2 and affected by absorption kinetics. When trap data are combined with SO2 flux measurements made through November 1996, Popocatepetl released about 3.9 Mt SO2, 16 Mt CO2, 0.75 Mt HCl, 0.075 Mt HF, 260 t As, 2.6 t Hg, and roughly 200 Mt H2O. Near-vent gas concentrations in the volcanic plume measured by correlation spectrometer (COSPEC) and Fourier transform infrared (FTIR) commonly exceed human recommended exposure limits and may constitute a potential health hazard. Volatile geochemistry combined with petrologic observations and melt-inclusion studies show that mafic magma injection into a preexisting silicic chamber has accompanied renewed volcanism at Popocatepetl. Minor assimilation of Cretaceous wall rocks probably occurred in mid-1994. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. US Geol Survey, Menlo Park, CA 94025 USA. Natl Autonomous Univ Mexico, Inst Geofis, Mexico City 04510, DF, Mexico. Univ Manitoba, Winnipeg, MB R3T 2N2, Canada. Arizona State Univ, Tempe, AZ 85287 USA. RP Goff, F (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. EM fraser@lanl.gov RI Delgado Granados, Hugo/J-3056-2013; OI Delgado Granados, Hugo/0000-0001-5263-7968; Siebe, Claus/0000-0002-3959-9028 NR 67 TC 60 Z9 60 U1 1 U2 8 PU ASSOC ENGINEERING GEOLOGISTS GEOLOGICAL SOCIETY AMER PI COLLEGE STN PA TEXAS A & M UNIV, DEPT GEOLOGY & GEOPHYSICS, COLLEGE STN, TX 77843-3115 USA SN 0016-7606 J9 GEOL SOC AM BULL JI Geol. Soc. Am. Bull. PD JUN PY 1998 VL 110 IS 6 BP 695 EP 710 DI 10.1130/0016-7606(1998)110<0695:GSOMVA>2.3.CO;2 PG 16 WC Geosciences, Multidisciplinary SC Geology GA ZU539 UT WOS:000074208200001 ER PT J AU Taylor, MJ Jahn, JM Fukao, S Saito, A AF Taylor, MJ Jahn, JM Fukao, S Saito, A TI Possible evidence of gravity wave coupling into the mid-latitude F region ionosphere during the SEEK campaign SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MIDLATITUDE IONOSPHERE AB On five of eight observation nights during the 1996 SEEK (Sporadic E Experiment over Kyushu) campaign, Japan, unusual "wave-like" structures were imaged in the 630 nm thermospheric nightglow emission. Four of these events were observed to travel towards the southwest, providing new evidence in support of recent theories describing the coupling of medium-scale gravity waves into the mid-latitude F region ionosphere. Available ionosonde data and the visual characteristics of the wave structures indicate no association with the occurrence of mid-latitude spread F or F region upwellings. Instead, the data support the novel concept of feedback from the ionosphere into the gravity wave, via the Perkins instability, to enhance its visibility. C1 Utah State Univ, Space Dynam Lab, Logan, UT 84322 USA. Utah State Univ, Dept Phys, Logan, UT 84322 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Kyoto Univ, Ctr Radio Atmospher Sci, Kyoto 606, Japan. RP Taylor, MJ (reprint author), Utah State Univ, Space Dynam Lab, Logan, UT 84322 USA. NR 11 TC 31 Z9 31 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 1 PY 1998 VL 25 IS 11 BP 1801 EP 1804 DI 10.1029/97GL03448 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZR962 UT WOS:000074033800011 ER PT J AU Reeves, GD AF Reeves, GD TI Relativistic electrons and magnetic storms: 1992-1995 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PREDICTION AB This paper examines the relationship between relativistic electron enhancements at geosynchronous orbit and magnetic storms measured by the Dst index. We analyzed the 30 most intense relativistic electron events from 1992 to 1995 and all events that occurred in 1993. Every relativistic electron event was associated with a magnetic storm in the Dst index, but, magnetic storms could occur with no appreciable enhancement of the relativistic electron fluxes. By correlating the maximum electron flux in each event with the minimum Dst value we found that the maximum relativistic electron fluxes and maximum ring current intensity are roughly correlated but that there is considerable variation. These results suggest that the solar wind conditions that are necessary to generate a ring current response are also necessary to generate a strong relativistic electron response but that there is some additional factor, either in the solar wind or in the magnetosphere, that determines whether a given storm will produce relativistic electrons or not and how strong that response will be. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Max Planck Inst Aeron, Katlenburg Lindau, Germany. RP Reeves, GD (reprint author), Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. EM reeves@lanl.gov RI Reeves, Geoffrey/E-8101-2011 OI Reeves, Geoffrey/0000-0002-7985-8098 NR 11 TC 104 Z9 110 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 1 PY 1998 VL 25 IS 11 BP 1817 EP 1820 DI 10.1029/98GL01398 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZR962 UT WOS:000074033800015 ER PT J AU Stephens, BB Keeling, RF Heimann, M Six, KD Murnane, R Caldeira, K AF Stephens, BB Keeling, RF Heimann, M Six, KD Murnane, R Caldeira, K TI Testing global ocean carbon cycle models using measurements of atmospheric O-2 and CO2 concentration SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Article ID GENERAL-CIRCULATION MODEL; NORTH-ATLANTIC; THERMOHALINE CIRCULATION; SIMULATIONS; TRANSPORT; DISTRIBUTIONS; DIOXIDE; OXYGEN; HEAT; RADIOCARBON AB We present a method for testing the performance of global ocean carbon cycle models using measurements of atmospheric O-2 and CO2 concentration. We combine these measurements to define a tracer, atmospheric potential oxygen (APO approximate to O-2 + CO2), which is conservative with respect to terrestrial photosynthesis and respiration. We then compare observations of APO to the simulations of an atmospheric transport model which uses ocean-model air-sea fluxes and fossil fuel combustion estimates as lower boundary conditions. We present observations of the annual-average concentrations of CO2, O-2, and APO at 10 stations in a north-south transect. The observations of APO show a significant interhemispheric gradient decreasing towards the north. We use air-sea CO2, O-2, and N-2 fluxes from the Princeton ocean biogeochemistry model, the Hamburg model of the ocean carbon cycle, and the Lawrence Livermore ocean biogeochemistry model to drive the TM2 atmospheric transport model. The latitudinal variations in annual-average APO predicted by the combined models are distinctly different from the observations. All three models significantly underestimate the interhemispheric difference in APO, suggesting that they underestimate the net southward transport of the sum of O-2 and CO2 in the oceans. Uncertainties in the model-observation comparisons include uncertainties associated with the atmospheric measurements, the atmospheric transport model, and the physical and biological components of the ocean models. Potential deficiencies in the physical components of the ocean models, which have previously been suggested as causes for anomalously large heat fluxes out of the Southern Ocean, may contribute to the discrepancies with the APO observations. These deficiencies include the inadequate parameterization of subgrid-scale isopycnal eddy mixing, a lack of subgrid-scale vertical convection, too much Antarctic sea-ice formation, and an overestimation of vertical diffusivities in the main thermocline. C1 Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. Max Planck Inst Meteorol, D-20146 Hamburg, Germany. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Bermuda Biol Stn Res Inc, Ferry Reach, St Georges, Bermuda. RP Stephens, BB (reprint author), Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. EM kenc@LLNL.gov; rkeeling@ucsd.edu; martin.heimann@dkrz.de; six@dlrz.de; rmurnane@bbsr.edu RI Stephens, Britton/B-7962-2008; Caldeira, Ken/E-7914-2011; Heimann, Martin/H-7807-2016; Murnane, Richard/G-7039-2015 OI Stephens, Britton/0000-0002-1966-6182; Heimann, Martin/0000-0001-6296-5113; Murnane, Richard/0000-0002-9744-8471 NR 55 TC 87 Z9 91 U1 0 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0886-6236 J9 GLOBAL BIOGEOCHEM CY JI Glob. Biogeochem. Cycle PD JUN PY 1998 VL 12 IS 2 BP 213 EP 230 DI 10.1029/97GB03500 PG 18 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA ZR755 UT WOS:000074010500001 ER PT J AU Thompson, M Rayner, S Ney, S AF Thompson, M Rayner, S Ney, S TI Risk and governance part II: Policy in a complex and plurally perceived world SO GOVERNMENT AND OPPOSITION LA English DT Article ID IIASA ENERGY C1 Musgrave Inst, London, England. Univ Bergen, Dept Polit, Bergen, Norway. Pacific NW Lab, Global Change Grp, Richland, WA 99352 USA. Interdisciplinary Ctr Comparat Res Social Sci, Vienna, Austria. RP Thompson, M (reprint author), Musgrave Inst, London, England. NR 42 TC 17 Z9 17 U1 0 U2 1 PU GOVERNMENT OPPOSITION LTD PI LONDON PA LONDON SCH OF ECON AND POL SCI HOUGHTON ST, LONDON, ENGLAND WC2 2AE SN 0017-257X J9 GOV OPPOS JI Gov. Oppos. PD SUM PY 1998 VL 33 IS 3 BP 330 EP 354 DI 10.1111/j.1477-7053.1998.tb00455.x PG 25 WC Political Science SC Government & Law GA 113KZ UT WOS:000075551300003 ER PT J AU Gilmore, T Davis, J Coates, J AF Gilmore, T Davis, J Coates, J TI Downhole weir for measuring flow rate in recirculation wells SO GROUND WATER MONITORING AND REMEDIATION LA English DT Article AB Recirculating wells are increasingly being used for ground water remediation and aquifer characterization investigations. Determination of now rate is required for proper design and spacing of recirculation wells. The measurement of flow rate, however, can be difficult using standard equipment. To overcome some of the flow measurement problems associated with more common measurement systems, a new device in the form of a downhole weir was developed for recirculating wells that use a two-casing design. The weir was designed to measure flow rates between 10 and 40 gpm. In this now range, the weir had an accuracy of +/- 2.8 gpm. This accuracy may be improved with some modifications. C1 Pacific NW Lab, Richland, WA 99352 USA. RP Gilmore, T (reprint author), Pacific NW Lab, POB 999, Richland, WA 99352 USA. NR 6 TC 2 Z9 2 U1 0 U2 0 PU GROUND WATER PUBLISHING CO PI WESTERVILLE PA 601 DEMPSEY RD, WESTERVILLE, OH 43081 USA SN 1069-3629 J9 GROUND WATER MONIT R JI Ground Water Monit. Remediat. PD SUM PY 1998 VL 18 IS 3 BP 146 EP 150 DI 10.1111/j.1745-6592.1998.tb00738.x PG 5 WC Water Resources SC Water Resources GA 113WX UT WOS:000075577800012 ER PT J AU Hubbell, JM Wood, TR Higgs, B Wylie, AH McElroy, DL AF Hubbell, JM Wood, TR Higgs, B Wylie, AH McElroy, DL TI Design, installation, and uses of combination ground water and gas sampling wells SO GROUND WATER MONITORING AND REMEDIATION LA English DT Article AB Waste disposal sites with volatile organic compounds(VOCs) frequently contain contaminants that are present in both,the ground water and vadose zone.: Vertical sampling is useful where transport of VOCs in the:vadose Zone may effect ground water and where steep vertical gradients in chemical concentrations are anticipated Designs for combination ground water and gas Sampling wells place:the tubing inside the casing with the sample port penetrating the casing for sampling. This physically interferes with pump or sampler:placement. This paper describes a well design that combines a ground water well with gas sampling ports by attaching the gas sampling tubing and ports to the exterior Of the casing. Placement::sf the tubing on the exterior of the casing allows exact definition of:gas port depth, reduces physical interference between the various monitoring equipment, and: allows simultaneous remediation and monitoring in a;single well. The usefulness and versatility of this design was demonstrated at the Idaho National Engineering and Environmental Laboratory (INEEL) with the installation:Of seven wells with 53 gas ports, in a geologic formation consisting of deep basalt with sedimentary interbeds at-depths from 7.2 to 178 m below land surface.: The INEEL combination well design is. easy to-construct, install, and operate. C1 Idaho Natl Engn Lab, Lockheed Martin Idaho Technol, Idaho Falls, ID 83415 USA. RP Hubbell, JM (reprint author), Idaho Natl Engn Lab, Lockheed Martin Idaho Technol, POB 1625, Idaho Falls, ID 83415 USA. NR 16 TC 4 Z9 4 U1 0 U2 1 PU GROUND WATER PUBLISHING CO PI WESTERVILLE PA 601 DEMPSEY RD, WESTERVILLE, OH 43081 USA SN 1069-3629 J9 GROUND WATER MONIT R JI Ground Water Monit. Remediat. PD SUM PY 1998 VL 18 IS 3 BP 151 EP 157 DI 10.1111/j.1745-6592.1998.tb00739.x PG 7 WC Water Resources SC Water Resources GA 113WX UT WOS:000075577800013 ER PT J AU Kryshev, II Romanov, GN Sazykina, TG Isaeva, LN Trabalka, JR Blaylock, BG AF Kryshev, II Romanov, GN Sazykina, TG Isaeva, LN Trabalka, JR Blaylock, BG TI Environmental contamination and assessment of doses from radiation releases in the Southern Urals SO HEALTH PHYSICS LA English DT Article DE accident analysis; contamination, environmental; Sr-90; Cs-137 ID RADIOACTIVE CONTAMINATION; AQUATIC ECOSYSTEMS; TECHA RIVER; AREAS AB The Southern Urals in Russia was contaminated by radioactive discharges into the Techa River (1949-1956), the Kyshtym accident (1957), and the current releases and discharges from the Mayak Nuclear Materials Production Complex. In this paper, the consequences of radioactive contamination of the Ural region are analyzed. The current content of Sr-90 in the components of food chains is as follows (Bq kg(-1) wet weight): potatoes, 0.2-6.7; grain, 0.5-12.6; milk, 0.2-6.3; beef, 0.2-1.7; lake water, 0.12-1.0 river water, 0.2-8.5; fish, 7-480; mushrooms, 400-1,100; and berries, 700-16,000, The content of Cs-137 is as follows: potatoes, 0.5-3.8; grain, 0.3-2.9; milk, 0.2-4.5; beef, 0.3-2.6; lake and river water, 0.002-0.019; fish, 2-32; mushrooms, 110-1,600; and berries, 150, A major fraction of the dose to humans comes from the consumption of local food products, including natural ones, which have higher contamination levels than agricultural products. The average annual dose rates in contaminated areas are (0.5-4) x 10(-4) Sv y(-1), which is Lower by a factor of 10(2)-10(4) than in the periods of "acute" exposure (1950-1951 and 1957-1958), Natural organisms received very high doses up to 200-800 Gy resulting from radioactive discharges into the Techa River and the radiation accident in 1957, In all cases, including the "acute" exposure followed by the chronic irradiation, the doses to biota were by a factor of 10-10(3) higher than those to humans. C1 Inst Expt Meteorol, Obninsk 249020, Kaluga Region, Russia. Mayak Nucl Mat Prod Complex, Expt Res Stn, Chelyabinsk 454060, Russia. Chelyabinsk Hydrometeorol Ctr, Chelyabinsk 454048, Russia. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. SENES Oak Ridge Inc, Ctr Risk Anal, Oak Ridge, TN 37830 USA. NR 43 TC 22 Z9 22 U1 1 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 JUN PY 1998 VL 74 IS 6 BP 687 EP 697 DI 10.1097/00004032-199806000-00006 PG 11 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 ZN597 UT WOS:000073661800006 PM 9600301 ER PT J AU Walker, D Moler, PE Buhlmann, KA Avise, JC AF Walker, D Moler, PE Buhlmann, KA Avise, JC TI Phylogeographic patterns in Kinosternon subrubrum and K-baurii based on mitochondrial DNA restriction analyses SO HERPETOLOGICA LA English DT Article DE mud turtles; phylogeography; gene flow; population structure; southeastern United States; Kinosternon ID MUD TURTLE; ENDONUCLEASES; TREES AB We used restriction assays of mitochondrial (mt) DNA to estimate phylogeographic variation in two sister taxa of mud turtles in the southeastern United States. Extensive mtDNA variation characterized Kinosternon subrubrum and, to a lesser degree, K. baurii. Each of 26 mtDNA haplotypes from the 83 assayed specimens was localized spatially. Collectively these mtDNA haplotypes demarcated four major matrilineal assemblages each with a well defined regional distribution: a western group (A) in Missouri and Louisiana, a central group (B) throughout the Gulf coastal states, an eastern group (C) along the Atlantic coastal states north of Florida, and a southern group (D) in peninsular Florida. All assayed samples of K. baurii belonged to the mtDNA C assemblage. The two species in Florida are thus highly distinct in mtDNA genotype, but they exhibit minimal mtDNA divergence along the Atlantic coastal states. These findings raise questions concerning the evolutionary history and taxonomy of these two recognized species, MtDNA phylogeographic patterns in the baurii/subrubrum complex are remarkably similar to those reported previously for two other southeastern kinosternids, Sternotherus minor and S. odoratus. C1 Univ Georgia, Dept Genet, Athens, GA 30602 USA. Florida Game & Fresh Water Fish Commiss, Wildlife Res Lab, Gainesville, FL 32601 USA. Savannah River Ecol Lab, Aiken, SC 29801 USA. RP Walker, D (reprint author), Univ Georgia, Dept Genet, Athens, GA 30602 USA. NR 33 TC 19 Z9 19 U1 1 U2 2 PU HERPETOLOGISTS LEAGUE PI EMPORIA PA EMPORIA STATE UNIV, DIVISION BIOLOGICAL SCIENCES, 1200 COMMERCIAL ST, EMPORIA, KS 66801-5087 USA SN 0018-0831 J9 HERPETOLOGICA JI Herpetologica PD JUN PY 1998 VL 54 IS 2 BP 174 EP 184 PG 11 WC Zoology SC Zoology GA ZU167 UT WOS:000074169000006 ER PT J AU Gibbons, JW AF Gibbons, JW TI Graduate education at a field research laboratory: Facing the challenge SO HERPETOLOGICA LA English DT Article DE academic program; education; field research; field station; graduate students; herpetological research students ID TURTLES AB Field research stations provide both challenges and opportunities for graduate students interested in reptiles and amphibians. To be successful professionally, a student must balance the excitement inherent in conducting herpetological research with a program that will gain the respect of a broad spectrum of the scientific community. Each field research station has characteristics that make it distinctive from all others, but most have had to consider two problems: intellectual isolation from a main campus and an academic image of not being scientifically rigorous, a consequence of being an enjoyable place to be. Three decades of experience with graduate students in herpetology at The University of Georgia's Savannah River Ecology Laboratory provide one example of how the challenges can be met and the opportunities optimized. C1 Savannah River Ecol Lab, Aiken, SC 29802 USA. RP Gibbons, JW (reprint author), Savannah River Ecol Lab, Drawer E, Aiken, SC 29802 USA. NR 7 TC 0 Z9 0 U1 1 U2 4 PU HERPETOLOGISTS LEAGUE PI JOHNSON CITY PA EAST TENNESSEE STATE UNIV, DEPT BIOLOGICAL SCIENCES, BOX 70726, JOHNSON CITY, TN 37614-0726 USA SN 0018-0831 J9 HERPETOLOGICA JI Herpetologica PD JUN PY 1998 VL 54 SU S BP S21 EP S30 PG 10 WC Zoology SC Zoology GA ZU653 UT WOS:000074219600006 ER PT J AU Munne, S Fung, J Cassel, MJ Marquez, C Weier, HUG AF Munne, S Fung, J Cassel, MJ Marquez, C Weier, HUG TI Preimplantation genetic analysis of translocations: case-specific probes for interphase cell analysis SO HUMAN GENETICS LA English DT Article ID HUMAN EMBRYOS; INSITU HYBRIDIZATION; SEGREGATION; BLASTOMERES; MOSAICISM; DIAGNOSIS; FISH AB Carriers of balanced translocations show an increased risk of infertility and spontaneous abortions, because of errors in gametogenesis, and constitute a significant fraction of patients seeking assisted reproduction. The objective of this study was to design approaches for preimplantation diagnosis of chromosome translocations and to apply such techniques to the selection of chromosomally normal or balanced embryos prior to their transfer to the mother's womb. Three slightly different approaches were assessed by means of chromosome-specific, non-isotopically labeled DNA probes and an assay based on fluorescence in situ hybridization- to score and characterize chromosomes in single blastomeres biopsied from embryos on their third day of development. The three approaches were used for preimplantation genetic diagnosis involving four couples who had enrolled in our IVF program and in which one of the partners was a carrier of one of the following translocations: 46,XX,t(12;20)(p13.1;q13.3), 46,XY,t(3;4) (p24;p15), 45,XY,der(14;15)(10q;10q), and 46,XY,t(6;11) (p22.l;p15.3). A total of 33 embryos were analyzed, of which 25 (75.8%) were found to be either unbalanced or otherwise chromosomally abnormal. Only a single embryo could be transferred to patients A and D, whereas three embryos were transferred to patient B in a total of two IVF cycles. Transfer of two embryos to patient C resulted in an ongoing pregnancy. Re-analysis of non-transferred embryos with additional probes confirmed the initial results in 95% (20/21) of the cases. In conclusion, case-specific translocation tests can be applied to any translocation carrier for the selection of normal or chromosomally balanced embryos prior to embryo transfer. This is expected significantly to increase the success rates in IVF cycles of translocation carriers, while preventing the spontaneous abortion or birth of abnormal offspring. C1 St Barnabas Med Ctr, Inst Reprod Med & Sci, Livingston, NJ 07052 USA. Univ Calif San Francisco, Dept Obstet Gynecol & Reprod Sci, Reprod Genet Unit, San Francisco, CA 94143 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP Munne, S (reprint author), St Barnabas Med Ctr, Inst Reprod Med & Sci, 101 Old Short Hills Rd,Suite 501, Livingston, NJ 07052 USA. EM santi.munne@embryos.net OI Munne, Santiago/0000-0002-1088-5565 NR 31 TC 77 Z9 85 U1 0 U2 3 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0340-6717 J9 HUM GENET JI Hum. Genet. PD JUN PY 1998 VL 102 IS 6 BP 663 EP 674 DI 10.1007/s004390050759 PG 12 WC Genetics & Heredity SC Genetics & Heredity GA 104HX UT WOS:000075009600011 PM 9703428 ER PT J AU Davis, SN Cecil, D Zreda, M Sharma, P AF Davis, SN Cecil, D Zreda, M Sharma, P TI Chlorine-36 and the initial value problem SO HYDROGEOLOGY JOURNAL LA English DT Article DE isotopes; USA; groundwater age ID COSMOGENIC HE-3; NORTH-AMERICA; DESERT SOILS; ICE CORE; CL-36; MOVEMENT; USA; GROUNDWATER; DEPOSITION; SUBSURFACE AB Chlorine-36 is a radionuclide with a half-life of 3.01 x 10(5)a. Most Cl-36 in the hydrosphere originates from cosmic radiation interacting with atmospheric gases. Large amounts were also produced by testing thermonuclear devices during 1952-58. Because the monovalent anion, chloride, is the most common form of chlorine found in the hydrosphere and because it is extremely mobile in aqueous systems, analyses of both total Cl- as well as 36Cl have been important in numerous hydrologic studies. In almost all applications of 36Cl, knowledge of the initial, or pre-anthropogenic, levels of Cl-36 is useful, as well as essential in some cases. Standard approaches to the determination of initial values have been to: (a) calculate the theoretical cosmogenic production and fallout, which varies according to latitude; (b) measure Cl-36 in present-day precipitation and assume that anthropogenic components can be neglected; (c) assume that shallow groundwater retains a record of the initial concentration; (d) extract Cl-36 from vertical depth profiles in desert soils; (e) recover Cl-36 from cores of glacial ice; and (f) calculate subsurface production of Cl-36 for water that has been isolated from the atmosphere for more than one million years. The initial value from soil profiles and ice cores is taken as the value that occurs directly below the depth of the easily defined bomb peak. All six methods have serious weaknesses. Complicating factors include Cl-36 concentrations not related to cosmogenic sources, changes in cosmogenic production with time, mixed sources of chloride in groundwater, melting and refreezing of water in glaciers, and seasonal groundwater recharge that does not contain average year-long concentrations of Cl-36. C1 Univ Arizona, Dept Hydrol & Water Resources, Tucson, AZ 85721 USA. US Geol Survey, INEL, Div Water Resources, Idaho Falls, ID 83403 USA. Purdue Univ, PRIME Lab, Pankaj Sharma Dept Phys, W Lafayette, IN 47907 USA. RP Davis, SN (reprint author), Univ Arizona, Dept Hydrol & Water Resources, Tucson, AZ 85721 USA. NR 39 TC 19 Z9 19 U1 1 U2 5 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1431-2174 J9 HYDROGEOL J JI Hydrogeol. J. PD JUN PY 1998 VL 6 IS 1 BP 104 EP 114 DI 10.1007/s100400050137 PG 11 WC Geosciences, Multidisciplinary; Water Resources SC Geology; Water Resources GA 187BH UT WOS:000079765800010 ER PT J AU Fogg, GE Noyes, CD Carle, SF AF Fogg, GE Noyes, CD Carle, SF TI Geologically based model of heterogeneous hydraulic conductivity in an alluvial setting SO HYDROGEOLOGY JOURNAL LA English DT Article DE USA; alluvial; sediments; heterogeneity sediments; statistical modeling; hydraulic conductivity ID GROUNDWATER HYDROLOGY; AQUIFER SYSTEM; FLOW; TRANSPORT; FIELDS AB Information on sediment texture and spatial continuity are inherent to sedimentary depositional facies descriptions, which are therefore potentially good predictors of spatially varying hydraulic conductivity (K). Analysis of complex alluvial heterogeneity in Livermore Valley, California, USA, using relatively abundant core descriptions and field pumping-test data, demonstrates a depositional-facies approach to characterization of subsurface heterogeneity. Conventional textural classifications of the core show a poor correlation with K; however, further refinement of the textural classifications into channel, levee, debris-flow and flood-plain depositional facies reveals a systematic framework for spatial modeling of K. This geologic framework shows that most of the system is composed of very low-K flood-plain materials, and that the K measurements predominantly represent the other, higher-K facies. Joint interpretation of both the K and geologic data shows that spatial distribution of K in this system could not be adequately modeled without geologic data and analysis. Furthermore, it appears that K should not be assumed to be log-normally distributed, except perhaps within each facies. Markov chain modeling of transition probability, representing spatial correlation within and among the facies, captures the relevant geologic features while highlighting a new approach for statistical characterization of hydrofacies spatial variability. The presence of fining-upward facies sequences, cross correlation between facies, as well as other geologic attributes captured by the Markov chains provoke questions about the suitability of conventional geostatistical approaches based on variograms or covariances for modeling geologic heterogeneity. C1 Univ Calif Davis, Davis, CA 95616 USA. Weiss Associates, Emeryville, CA USA. RP Fogg, GE (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94551 USA. NR 49 TC 95 Z9 96 U1 3 U2 20 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1431-2174 J9 HYDROGEOL J JI Hydrogeol. J. PD JUN PY 1998 VL 6 IS 1 BP 131 EP 143 DI 10.1007/s100400050139 PG 13 WC Geosciences, Multidisciplinary; Water Resources SC Geology; Water Resources GA 187BH UT WOS:000079765800012 ER PT J AU Maurice, D Hawk, JA AF Maurice, D Hawk, JA TI Ferric chloride leaching of mechanically activated chalcopyrite SO HYDROMETALLURGY LA English DT Article ID SULFATE; MEDIA AB Mechanical activation is a means of accelerating the leaching process. Contributing to the success of this technique are (1) increased surface area; (2) increased surface reactivity; and (3) the microstructural modifications stemming from the deformation. Previous studies have focused on gaining a fundamental understanding of these factors. Tl-is study represents a divergence from this approach, as we set out to determine the effectiveness of the technique when applied on a scale more reflective of how the process might actually be practised. To this end, chalcopyrite was autogenously milled in a horizontal mill, and leaching was conducted using a 5 M chloride leach solution. Leaching of as-received concentrate resulted in copper extractions of 75% in 5 h of leaching, whereas leaching mechanically activated concentrates resulted in copper extractions over 95% after 3 h of leaching. This study investigated the critical parameters affecting the efficiency of mechanical activation as a means of accelerating the oxidative leaching of sulfide minerals. The processes of attrition and fragmentation enhance reaction rates by increasing both the surface area and the density of defects. A small laboratory shaker mill and a small tumbling mill were used to mechanically process chalcopyrite; the former using steel grinding media, the latter using sized ore. The increase in surface area was determined using BET; and X-ray diffraction analysis was utilized to determine the full width at half maximum (FWHM) for chalcopyrite, which is subsequently used as a marker of the relative deformation. Leaching experiments were conducted with as-received concentrate and with processed concentrate. The contributions of the increased surface area and the deformed structure were correlated with the leaching kinetics. (C) 1998 Elsevier Science B.V. All rights reserved. C1 US DOE, Albany Res Ctr, Albany, OR 97321 USA. RP Maurice, D (reprint author), US DOE, Albany Res Ctr, Albany, OR 97321 USA. NR 12 TC 39 Z9 47 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-386X J9 HYDROMETALLURGY JI Hydrometallurgy PD JUN PY 1998 VL 49 IS 1-2 BP 103 EP 123 DI 10.1016/S0304-386X(98)00013-9 PG 21 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA ZZ558 UT WOS:000074742200007 ER PT J AU Koplow, JP Goldberg, L Kliner, DAV AF Koplow, JP Goldberg, L Kliner, DAV TI Compact 1-W Yb-doped double-cladding fiber amplifier using V-groove side-pumping SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Article DE optical fiber amplifiers; optical fiber devices; ytterbium ID LASER; OPERATION AB A compact packaged fiber amplifier was constructed using a Yb-doped double-cladding fiber, which was V-groove side-pumped by a laser diode operating at 975 nm, Under saturation, the amplifier generated 1 W at 1064 nm, The small-signal gain reached a maximum of 50 dB at 1075 nm and was greater than 40 dB in the range of 1042-1093 nm. C1 USN, Res Lab, Div Opt Sci, Washington, DC 20375 USA. Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. RP Koplow, JP (reprint author), USN, Res Lab, Div Opt Sci, Washington, DC 20375 USA. NR 12 TC 21 Z9 22 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1041-1135 J9 IEEE PHOTONIC TECH L JI IEEE Photonics Technol. Lett. PD JUN PY 1998 VL 10 IS 6 BP 793 EP 795 DI 10.1109/68.681486 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA ZN391 UT WOS:000073641200015 ER PT J AU Tian, SY Morris, MF Morris, SJ Obradovic, B Wang, G Tasch, AF Snell, CM AF Tian, SY Morris, MF Morris, SJ Obradovic, B Wang, G Tasch, AF Snell, CM TI A detailed physical model for ion implant induced damage in silicon SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article DE implant-induced damage; ion implantation; ion radiation effects; modeling; Monte Carlo methods ID MONTE-CARLO SIMULATION; SINGLE-CRYSTAL SILICON; POINT-DEFECTS; COMPUTER-SIMULATION; DIFFUSION; BORON; ACCUMULATION; TEMPERATURE; CASCADES; SOLIDS AB A unified physically based ion implantation damage model has been developed which successfully predicts both the impurity profiles and the damage profiles for a wide range of implant conditions for arsenic, phosphorus, BF2, and boron implants into single-crystal silicon. In addition, the amorphous layer thicknesses predicted by this new damage model are also in excellent agreement with experimental measurements, This damage model is based on the physics of point defects in silicon, and explicitly simulates the defect production, diffusion, and their interactions which include interstitial-vacancy recombination, clustering of same type of defects, defect-impurity complex formation, emission of mobile defects from clusters, and surface effects for the first time. New computationally efficient algorithms have been developed to overcome the barrier of the excessive computational requirements. In addition, the new model has been incorporated in the UT-MARLOWE ion implantation simulator, and has been developed primarily for use in engineering workstations. This damage model is the most physical model in the literature to date within the framework of the binary collision approximation (BCA), and provides the required, accurate as-implanted impurity profiles and damage profiles for transient enhanced diffusion (TED) simulation. C1 Univ Texas, Microelect Res Ctr, Austin, TX 78712 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Tian, SY (reprint author), Avant, TCAD Business Unit, Fremont, CA 94538 USA. NR 40 TC 26 Z9 27 U1 1 U2 7 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9383 J9 IEEE T ELECTRON DEV JI IEEE Trans. Electron Devices PD JUN PY 1998 VL 45 IS 6 BP 1226 EP 1238 DI 10.1109/16.678523 PG 13 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA ZN241 UT WOS:000073624000011 ER PT J AU Kueck, JD Casada, DA Otaduy, PJ AF Kueck, JD Casada, DA Otaduy, PJ TI A comparison of two energy efficient motors SO IEEE TRANSACTIONS ON ENERGY CONVERSION LA English DT Article; Proceedings Paper CT 7th Annual Predictive Maintenance Technology National Conference CY DEC 04-06, 1995 CL INDIANAPOLIS, INDIANA AB Limited testing provides evidence that a particular energy efficient motor (EEM) appears to have a unique susceptibility to reduced negative sequence impedance. The effect of the reduction in negative sequence impedance is to allow a higher negative sequence current now under conditions of voltage unbalance or negative sequence harmonic distortion in the bus voltage. This higher current flow results in additional heating of the rotor and 120 Hz vibration, and may combine with other conditions to cause premature failure. In addition, energy efficient motors operate at slightly higher speeds, and may sometimes cause the driven loads to require more horsepower from the motor causing further overheating. Existing industry guidance for the application of three phase motors in poor power quality environments may be inadequate because this guidance does not consider the combined effect of such conditions as voltage unbalance, harmonic distortion and over voltage. A specific application of an EEM is studied in this paper; the motor may be failing due to a combination of over voltage, voltage unbalance, harmonic distortion and loading the motor to full rated load, while the motor has a Service Factor of 1.0. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Kueck, JD (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 13 TC 2 Z9 2 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0885-8969 J9 IEEE T ENERGY CONVER JI IEEE Trans. Energy Convers. PD JUN PY 1998 VL 13 IS 2 BP 140 EP 147 DI 10.1109/60.678977 PG 8 WC Energy & Fuels; Engineering, Electrical & Electronic SC Energy & Fuels; Engineering GA ZQ035 UT WOS:000073814900006 ER PT J AU Vogel, CR Oman, ME AF Vogel, CR Oman, ME TI Fast, robust total variation-based reconstruction of noisy, blurred images SO IEEE TRANSACTIONS ON IMAGE PROCESSING LA English DT Article DE cell-centered finite differences; conjugate gradient; deconvolution; fixed point iteration; image reconstruction; preconditioner; regularization; total variation ID RESTORATION; RECOVERY AB Tikhonov regularization with a modified total variation regularization functional is used to recover an image from noisy, blurred data. This approach is appropriate for image processing in that it does not place a priori smoothness conditions on the solution image. An efficient algorithm is presented for the discretized problem that combines a fixed point iteration to handle nonlinearity with a new, effective preconditioned conjugate gradient iteration for large linear systems. Reconstructions, convergence results, and a direct comparison with a fast linear solver are presented for a satellite image reconstruction application. C1 Montana State Univ, Dept Math Sci, Bozeman, MT 59717 USA. Iowa State Univ, US DOE, Ames, IA 50011 USA. RP Vogel, CR (reprint author), Montana State Univ, Dept Math Sci, Bozeman, MT 59717 USA. EM vogel@math.montana.edu; oman@ameslab.gov NR 34 TC 344 Z9 376 U1 3 U2 27 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1057-7149 J9 IEEE T IMAGE PROCESS JI IEEE Trans. Image Process. PD JUN PY 1998 VL 7 IS 6 BP 813 EP 824 DI 10.1109/83.679423 PG 12 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA ZP633 UT WOS:000073773000004 PM 18276295 ER PT J AU dos Santos, JMF Soares, AJVD Monteiro, CMB Morgado, RE Conde, CAN AF dos Santos, JMF Soares, AJVD Monteiro, CMB Morgado, RE Conde, CAN TI The application of the curved-grid technique to a gas proportional scintillation counter with a small-diameter photo-multiplier tube SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO ID X-RAY SPECTROMETRY; PERFORMANCE AB The curved-grid technique was developed to maintain the superior performance of large-area gas proportional scintillation counters (GPSCs) without resorting to complex and bulky focusing systems or large photomultiplier tubes (PMTs) for applications in energy-dispersive x-ray fluorescence analysis. The technique is a simple method to compensate for the variation in solid angle viewed by the PMT as a function of the radial distance from the cylindrical axis of the detector. The feasibility of the technique is demonstrated in a GPSC, by measuring the energy resolution as a function of entrance window diameter. With a properly shaped curved grid, no degradation in detector energy resolution is observed even when the effective detector sensitive area is increased approximately six-fold. The maximum ratio of detector entrance window to PMT diameter achieved thus far is approximately 0.75. C1 Univ Coimbra, Dept Phys, P-3000 Coimbra, Portugal. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP dos Santos, JMF (reprint author), Univ Coimbra, Dept Phys, P-3000 Coimbra, Portugal. EM Fcjmf@gemini.ci.uc.pt RI dos Santos, Joaquim/B-3058-2015; OI Monteiro, Cristina Maria Bernardes/0000-0002-1912-2804; dos Santos, Joaquim Marques Ferreira/0000-0002-8841-6523 NR 20 TC 7 Z9 7 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 229 EP 233 DI 10.1109/23.682385 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200003 ER PT J AU Hong, WS Cho, HS Biagi, S Retiere, F Kadyk, J Perez-Mendez, V Palaio, N Vujic, J AF Hong, WS Cho, HS Biagi, S Retiere, F Kadyk, J Perez-Mendez, V Palaio, N Vujic, J TI Gas avalanche pixel detectors with amorphous silicon carbide (a-Si : C : H) overcoating SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO ID ELECTRONIC CONDUCTIVITY; MICROSTRIP CHAMBERS; PERFORMANCE; SUBSTRATA; GLASS AB Performance of the gas avalanche pixel detectors of square and circular geometry, with and without semiconducting surface coating, was characterized in terms of gas gain and active region. Although the electric field profile of the square geometry cannot be radially uniform, a 200 mu m pitch detector of this type exhibited a maximum gain of similar to 12000 which is comparable to that of the circular counterpart. Due to the existence of the anode bus lines passing under the cathodes, there is a defocusing effect of the drift field lines converging to the anodes, resulting in inactive regions where electrons produced from gas ionization are not collected at the anodes. Variation of the count rate with the drift field was measured to probe these defocusing effects. The p-type a-Si:C:H surface coating was effective in reducing these inactive regions. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Univ Liverpool, Dept Phys, Liverpool L69 3BX, Merseyside, England. Univ Calif Berkeley, Dept Nucl Engn, Berkeley, CA 94720 USA. RP Hong, WS (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Engn, Berkeley, CA 94720 USA. NR 17 TC 6 Z9 6 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 252 EP 257 DI 10.1109/23.682389 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200007 ER PT J AU Cho, HS Hong, WS Perez-Mendez, V Kadyk, J Palaio, N Vujic, J AF Cho, HS Hong, WS Perez-Mendez, V Kadyk, J Palaio, N Vujic, J TI A columnar cesium iodide (CsI) drift plane layer for gas avalanche microdetectors SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO ID AMORPHOUS-SILICON; LOW-PRESSURE; CHAMBERS; EMISSION AB A new method is proposed to improve the spatial and time resolutions, and the detection efficiency with respect to the angle of the incident particles, for gas avalanche micro detectors. The new technique uses a thin (similar to 200 mu m) columnar CsI layer at the drift plane that acts as an efficient source of electrons produced by secondary emission due to the incident particles, and as an electron multiplier. In this paper, we present the measurements of the electron multiplication factor and detection efficiency of this layer, using a Sr-90 beta-source. C1 Univ Calif Berkeley, Dept Nucl Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Engn, Berkeley, CA 94720 USA. RP Cho, HS (reprint author), Univ Calif Berkeley, Dept Nucl Engn, Berkeley, CA 94720 USA. NR 16 TC 7 Z9 7 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 275 EP 279 DI 10.1109/23.682393 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200011 ER PT J AU Cho, HS Palaio, N Hong, WS Kadyk, J Perez-Mendez, V Vujic, J AF Cho, HS Palaio, N Hong, WS Kadyk, J Perez-Mendez, V Vujic, J TI Use of tungsten anodes in microgap gas chambers SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO ID LARGE-AREA; DETECTOR AB In a continuation of our earlier tests[1,2], tungsten has been used for anode strips in the fabrication of microgap gas chambers (MGCs) in an attempt to find a metallization suitable for gas avalanche microdetectors (MSGCs or MGCs) that will be both highly robust against sparking and yet have sufficiently low resistivity to permit use of detectors of relatively larger sizes. MGCs having about 5500 and 7500 Angstrom thick tungsten anodes were fabricated using a sputtering technique, and the sheet resistances for these layers were measured as 0.42 and 0.27 Ohm/square, respectively. The detectors were subjected to sparks having a range of energies, and the damage to the anode strips was assessed using optical and scanning electron microscope (SEM) photographs, and by measuring leakage current before and after sparking. In this paper, the spark damage test results of tungsten anodes in MGCs are reported, and an interpretation is made regarding the viability of use of this metal for larger sizes of detectors. C1 Univ Calif Berkeley, Dept Nucl Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Engn, Berkeley, CA 94720 USA. RP Cho, HS (reprint author), Univ Calif Berkeley, Dept Nucl Engn, Berkeley, CA 94720 USA. NR 18 TC 3 Z9 3 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 280 EP 284 DI 10.1109/23.682394 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200012 ER PT J AU Sudharsanan, R Greenwald, AC Vakerlis, G Yoganathan, M Cho, HS Kadyk, J Dubeau, J Dixit, M AF Sudharsanan, R Greenwald, AC Vakerlis, G Yoganathan, M Cho, HS Kadyk, J Dubeau, J Dixit, M TI High resistivity ZnSe coated substrates for microstrip gas chambers SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO ID ELECTRONIC CONDUCTIVITY; GLASS; PERFORMANCE; DETECTORS AB Microstrip gas chambers (MSGCs) require substrates with sheet resistance in the range of 10(13)-10(16) ohms/square to eliminate polarization and surface charging effects between the electrodes. Thin films of II-VI semiconductors deposited on glass or plastic substrates are attractive for this application since bulk resistivity of these semiconductors vary in the range 10(9)-10(12) ohm-cm and films with good uniformity can be deposited over large-areas using inexpensive deposition techniques. In this paper, deposition, characterization, and fabrication of MSGCs using ZnSe thin films are reported for the first time. ZnSe thin films were deposited on glass and plastic substrates by thermal evaporation. Sheet resistance of ZnSe varied in the range of 10(15) to 10(16) ohms/square depending on the deposition conditions. A MSGC detector fabricated using a 0.5 mu m thick ZnSe layer on glass substrate exhibited best values; gas gain of 25000 and an energy resolution of about 16.7% FWHM at a gain of 1080 for a Fe-55 source. C1 Spire Corp, Bedford, MA 01730 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Phys, Berkeley, CA 94720 USA. Carleton Univ, Ctr Res Particle Phys, Ottawa, ON K1S 5B6, Canada. RP Sudharsanan, R (reprint author), Spire Corp, 1 Patriots Pk, Bedford, MA 01730 USA. NR 12 TC 4 Z9 4 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 285 EP 289 DI 10.1109/23.682395 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200013 ER PT J AU Pandey, SU Bellwied, R Beuttenmueller, R Caines, H Chen, W DiMassimo, D Dyke, H Hall, J Hoffmann, GW Humanic, TJ Kuczewski, P Kotov, IV Kraner, HW Leonhardt, B Liaw, CJ Li, Z Lo Curto, G Lynn, D Middelkamp, P Ott, G Pruneau, C Rykov, V Schambach, J Sedlmeir, J Sheen, J Soja, B Sugarbaker, E Takahashi, J Wilson, WK AF Pandey, SU Bellwied, R Beuttenmueller, R Caines, H Chen, W DiMassimo, D Dyke, H Hall, J Hoffmann, GW Humanic, TJ Kuczewski, P Kotov, IV Kraner, HW Leonhardt, B Liaw, CJ Li, Z Lo Curto, G Lynn, D Middelkamp, P Ott, G Pruneau, C Rykov, V Schambach, J Sedlmeir, J Sheen, J Soja, B Sugarbaker, E Takahashi, J Wilson, WK TI Measurement of two particle resolution in silicon drift detectors. SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO ID CHAMBERS AB A study resolving two hits in a 45x45 mm rectangular n-type Silicon Drift Detector is presented as a function of drift field using a pulsed Nd:Yag laser. The data are analyzed under the assumption of the general form of a Gaussian distribution in two variables (including correlations). The two hit resolving power degrades with drift distance. As the two electron clouds approach each other their correlation coefficients are shown to increase and be anti-correlated. Arguments for optimal two hit resolution versus drift field are presented. A simple method to determine whether electron cloud distributions arise from multiple overlapping hits or single hits is demonstrated. Practical implications for analyzing data from high occupancy experiments such as STAR at the RHIC collider are discussed. C1 Wayne State Univ, Detroit, MI 48201 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Ohio State Univ, Columbus, OH 43210 USA. Univ Texas, Austin, TX 78712 USA. Protvino High Energy Phys Inst, Protvino 142284, Russia. Univ Sao Paulo, Sao Paulo, Brazil. RP Pandey, SU (reprint author), Wayne State Univ, Detroit, MI 48201 USA. RI Takahashi, Jun/B-2946-2012 OI Takahashi, Jun/0000-0002-4091-1779 NR 11 TC 5 Z9 5 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 315 EP 321 DI 10.1109/23.682400 PG 7 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200018 ER PT J AU Gomez, A Kroeger, W Nissen, T Sadrozinski, HFW Wichmann, R Emes, J Gilchriese, MGD Siegrist, J Wappler, F Unno, Y Ohsugi, T AF Gomez, A Kroeger, W Nissen, T Sadrozinski, HFW Wichmann, R Emes, J Gilchriese, MGD Siegrist, J Wappler, F Unno, Y Ohsugi, T TI Pulse height of MIP's in an n-side silicon microstrip detector after proton irradiation with a fluence of 1x10(15) p cm(-2) SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO AB We have irradiated an n-side silicon microstrip detector to an equivalent high energy fluence of 1 x 10(15) pcm(-2) using 55 MeV protons. We determined the median pulse height to be 0.7 fC at a bias voltage of 180 V, and deduced a depletion region of about 80 mu m. C1 Univ Calif Santa Cruz, Santa Cruz Inst Particle Phys, Santa Cruz, CA 95064 USA. LBNL, Berkeley, CA 94270 USA. SUNY Albany, Albany, NY 12222 USA. Natl Lab High Energy Phys, KEK, Tsukuba, Ibaraki 305, Japan. Hiroshima Univ, Hiroshima, Japan. RP Gomez, A (reprint author), Univ Calif Santa Cruz, Santa Cruz Inst Particle Phys, Santa Cruz, CA 95064 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 327 EP 330 DI 10.1109/23.682402 PG 4 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200020 ER PT J AU Chen, W Eremin, V Li, Z Menichelli, D Wang, Q Zhao, L Chien, CY Xie, X Anderson, D Kwan, S AF Chen, W Eremin, V Li, Z Menichelli, D Wang, Q Zhao, L Chien, CY Xie, X Anderson, D Kwan, S TI Design and processing of various configurations of silicon pixel detectors for high irradiation tolerance up to 6x10(14) n/cm(2) in LHC application SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO AB Various new configurations of silicon pixel detector have been designed and are in prototype production. The material selection and detector design are aimed to produce silicon detectors with radiation tolerance up to 6x10(14) n/cm(2) (or 4x10(14) pi/cm(2)) in LHC environment, which corresponds to a net increase (with long term anneal) of space charge of about 4.2x10(13) cm(-3). The configuration of n(+)/n/p(+), with multi-guard-rings structure for high voltage (up to 300 volts) operation, has been used for the purpose to make the detector insensitive to space charge sign inversion. The material selection of medium resistivity (1.9k Ohm-cm) n-type silicon has been made to try a new solution in extending detector lifetime: it should be the first step toward the use of low resistivity silicon, to prevent type inversion. The traditional configuration of p(+)/n/n(+), with multi-guard-ring structure and n-type material, has also been used with the same layout, to get a comparison. It is shown that the fabrication of n(+)/n/p(+) pixel detectors requires eight mask steps, while just four mask steps are required for the p(+)/n/n(+) configuration. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Fermilab Astrophys Ctr, Batavia, IL 60510 USA. RP Chen, W (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. NR 5 TC 10 Z9 10 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 348 EP 353 DI 10.1109/23.682406 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200024 ER PT J AU Unno, Y Kitabayashi, H Dick, B Dubbs, T Grillo, A Ikeda, M Iwata, Y Kashigin, S Kitayama, E Kroeger, W Kohriki, T Kondo, T Moorhead, G Morgan, D Nakano, I Ohmoto, T Ohsugi, T Phillips, PW Richardson, J Rowe, W Sadrozinski, HFW Sato, K Siegrist, J Spencer, E Spieler, H Takashima, R Taylor, G Terada, S Umeda, T Wilder, M Wyllie, K Yagi, H AF Unno, Y Kitabayashi, H Dick, B Dubbs, T Grillo, A Ikeda, M Iwata, Y Kashigin, S Kitayama, E Kroeger, W Kohriki, T Kondo, T Moorhead, G Morgan, D Nakano, I Ohmoto, T Ohsugi, T Phillips, PW Richardson, J Rowe, W Sadrozinski, HFW Sato, K Siegrist, J Spencer, E Spieler, H Takashima, R Taylor, G Terada, S Umeda, T Wilder, M Wyllie, K Yagi, H TI Evaluation of p-stop structures in the n-side of n-on-n silicon strip detector SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NM AB Large area (63.6 mm x 64 mm) n-on-n silicon strip detectors have been fabricated, implementing various p-stop structures in the n-side. The detectors were characterized in laboratory and in beamtests. The beamtests showed that the individual p-stop structure collected less charge in the region between the strips than other p-stop structures. C1 High Energy Accelerator Res Org, Inst Particle & Nucl Studies, Tsukuba, Ibaraki 305, Japan. Hiroshima Univ, Dept Phys, Hiroshima 739, Japan. Univ Cambridge, Cavendish Lab, Cambridge CB3 0HE, England. Kyoto Univ, Dept Educ, Fushimi Ku, Kyoto 612, Japan. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Phys, Berkeley, CA 94720 USA. Univ Liverpool, Dept Phys, Liverpool L69 7ZE, Merseyside, England. Univ Melbourne, Sch Phys, Parkville, Vic 3052, Australia. Okayama Univ, Dept Phys, Okayama 700, Japan. Rutherford Appleton Lab, Particle Phys Dept, Didcot OX11 0QX, Oxon, England. Univ Calif Santa Cruz, Inst Particle Phys SCIPP, Santa Cruz, CA 95064 USA. Univ Sheffield, Dept Phys, Sheffield S3 7RH, S Yorkshire, England. RP High Energy Accelerator Res Org, Inst Particle & Nucl Studies, Oho 1-1, Tsukuba, Ibaraki 305, Japan. RI Moorhead, Gareth/B-6634-2009 OI Moorhead, Gareth/0000-0002-9299-9549 NR 6 TC 13 Z9 13 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9499 EI 1558-1578 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 401 EP 405 DI 10.1109/23.682416 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200034 ER PT J AU Tull, CR Ludewigt, BA Lewak, D AF Tull, CR Ludewigt, BA Lewak, D TI Spectral response of multi-element silicon x-ray detectors SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO ID HIGH-RESISTIVITY SILICON; SIMULATION; DEVICES AB An x-ray spectrometer combining multi-element silicon detectors and multi-channel integrated circuit pulse-processing electronics is being developed for low noise, high count rate synchrotron x-ray fluorescence applications. This paper reports on the issues surrounding the use of highly segmented silicon detectors for x-ray spectroscopy. Several different detector geometries were modeled using commercially available device simulation software, and selected geometries were fabricated using planar processing techniques on high resistivity silicon. The detectors were characterized using a 5 mu m diameter 8.5 keV x-ray beam, and Fe-55 and Cd-109 radioisotope sources. Spectral background, anomalous peaks, peak-to-background and charge sharing between adjacent detector elements were studied. The measured x-ray spectral responses are interpreted with respect to the device simulations. These measurements bring to light the effects of detector design, detector processing techniques and detector materials properties on the spectral response of the detector. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Microprose Inc, Alameda, CA USA. RP Tull, CR (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 15 TC 10 Z9 10 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 421 EP 427 DI 10.1109/23.682420 PG 7 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200038 ER PT J AU Adam, I Aleksan, R Aston, D Bailly, P Beigbeder, C Benayoun, M Benkebil, M Bonneaud, G Breton, D Briand, H Brown, D Bourgeois, P Chauveau, J Cizeron, R Cohen-Tanugi, J Convery, M David, P de la Vaissiere, C de Lesquen, A del Buono, L Fouque, G Gaidot, A Gastaldi, F Genat, JF Gosset, L Hale, D de Monchenault, GH Hamon, O Kadel, R Kadyk, J Karolak, M Kawahara, H Krueger, H Lebbolo, H Leruste, PH Le Diberder, F London, G Long, M Lory, J Lu, A Lutz, AM Lynch, G McCulloch, M McShurley, D Malchow, R Matricon, P Mayer, B Meadows, B Narjoux, JL Noppe, JM Oshatz, D Oxoby, G Plano, R Plaszczynski, S Pripstein, M Rasson, J Ratcliff, B Reif, R Renard, C Roos, L Roussot, E Sarazin, X Schune, MH Schwiening, J Sen, S Shelkov, V Sokoloff, M Staengle, H Stiles, P Stone, R Thiebaux, C Truong, K Toki, W Vasileiadis, G Vasseur, G Va'vra, J Verderi, M Versille, S Warner, D Weber, T Weber, TF Wenzel, W Wilson, R Wormser, G Yeche, C Yellin, S Zhang, B Zito, M AF Adam, I Aleksan, R Aston, D Bailly, P Beigbeder, C Benayoun, M Benkebil, M Bonneaud, G Breton, D Briand, H Brown, D Bourgeois, P Chauveau, J Cizeron, R Cohen-Tanugi, J Convery, M David, P de la Vaissiere, C de Lesquen, A del Buono, L Fouque, G Gaidot, A Gastaldi, F Genat, JF Gosset, L Hale, D de Monchenault, GH Hamon, O Kadel, R Kadyk, J Karolak, M Kawahara, H Krueger, H Lebbolo, H Leruste, PH Le Diberder, F London, G Long, M Lory, J Lu, A Lutz, AM Lynch, G McCulloch, M McShurley, D Malchow, R Matricon, P Mayer, B Meadows, B Narjoux, JL Noppe, JM Oshatz, D Oxoby, G Plano, R Plaszczynski, S Pripstein, M Rasson, J Ratcliff, B Reif, R Renard, C Roos, L Roussot, E Sarazin, X Schune, MH Schwiening, J Sen, S Shelkov, V Sokoloff, M Staengle, H Stiles, P Stone, R Thiebaux, C Truong, K Toki, W Vasileiadis, G Vasseur, G Va'vra, J Verderi, M Versille, S Warner, D Weber, T Weber, TF Wenzel, W Wilson, R Wormser, G Yeche, C Yellin, S Zhang, B Zito, M TI An internally reflecting Cherenkov detector (DIRC): Properties of the fused silica radiators SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO AB The DIRC, a new type of ring-imaging Cherenkov detector that images internally reflected Cherenkov light, is being constructed as the main hadronic particle identification component of the BABAR detector at SLAC. The device makes use of 5 meter long fused silica (colloquially called quartz) bars, which serve both as the Cherenkov radiators and as light pipes for transmitting the light to an array of photo-multiplier tubes. This paper describes a program of research and development aimed at determining whether bars that meet the stringent requirements of the DIRC can be obtained from commercial sources. The results of studies of bulk absorption of fused silica, surface finish, radiation damage and bulk inhomogeneities are discussed. C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. CENS, CEA, DAPNIA, F-91191 Gif Sur Yvette, France. Univ Paris 06, LPNHE, F-75252 Paris, France. Univ Paris 07, LPNHE, F-75252 Paris 05, France. Univ Paris Sud, LAL Orsay, F-91405 Orsay, France. Ecole Polytech, LPNHE, F-91128 Palaiseau, France. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Colorado State Univ, Dept Phys, Ft Collins, CO 80523 USA. Univ Cincinnati, Dept Phys, Cincinnati, OH 45221 USA. Rutgers State Univ, Dept Phys, Piscataway, NJ 08855 USA. Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China. RP Adam, I (reprint author), Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. OI Hamel de Monchenault, Gautier/0000-0002-3872-3592; Wilson, Robert/0000-0002-8184-4103 NR 11 TC 9 Z9 9 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 450 EP 455 DI 10.1109/23.682425 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200043 ER PT J AU Moses, WW Weber, MJ Derenzo, SE Perry, D Berdahl, P Boatner, LA AF Moses, WW Weber, MJ Derenzo, SE Perry, D Berdahl, P Boatner, LA TI Prospects for dense, infrared emitting scintillators SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NM ID FLUORESCENT LIFETIME MEASUREMENTS; INORGANIC SCINTILLATORS; LIGHT; SYSTEM AB We present results from an ongoing search fur inorganic scintillators for x-ansi gamma-ray detection. We measure the scintillation properties (luminous efficiency, decay time, and emission wavelength) of powdered samples excited by brief x-ray pulses. To find scintillators that are compatible with silicon photodetectors, we have tested over 1,100 samples using a photomultiplier tube with a GaAs:Cs photocathode, which is sensitive to 200-950 nm emissions. Optical filters are used to block emissions that are observable with bialkali PMTs. Several lanthanide and transition metal ions, molecular complexes, and II-VI compounds are known to have strong emissions at wavelengths >500 nm. We find that several compounds exhibit emission intensities comparable to commercial phosphors in the 600-900 nm range, including Eu and Sm doped LuPO4, ScPO4, and YPO4. Significant emissions are also observed from Tb, Dy, Er, Pr, and Tm doped phosphates, as well as several intrinsic compounds, notably Hg2Cl2. Scintillation characteristics of promising compounds (in powdered or small crystal form) are presented. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RI Boatner, Lynn/I-6428-2013 OI Boatner, Lynn/0000-0002-0235-7594 NR 20 TC 38 Z9 38 U1 1 U2 18 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9499 EI 1558-1578 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 462 EP 466 DI 10.1109/23.682427 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200045 ER PT J AU Wojcik, R Majewski, S Kross, B Steinbach, D Weisenberger, AG AF Wojcik, R Majewski, S Kross, B Steinbach, D Weisenberger, AG TI High spatial resolution gamma imaging detector based on a 5 '' diameter R3292 Hamamatsu PSPMT SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO AB High resolution imaging gamma-ray detectors were developed using Hamamatsu's 5 " diameter R3292 position sensitive PMT (PSPMT) [1] and a variety of crystal scintillator arrays. Special readout techniques were used to maximize the active imaging area while reducing the number of readout channels. Spatial resolutions approaching 1 mm were obtained in a broad energy range from 20 to 511 keV. Results are also presented of coupling the scintillator arrays to the PMT via imaging light guides consisting of acrylic optical fibers. C1 Jefferson Lab, Newport News, VA 23606 USA. Coll William & Mary, Dept Phys, Williamsburg, VA 23187 USA. RP Wojcik, R (reprint author), Jefferson Lab, 12000 Jefferson Ave, Newport News, VA 23606 USA. NR 7 TC 66 Z9 70 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 487 EP 491 DI 10.1109/23.682432 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200050 ER PT J AU Whitley, CR Bounds, JA Steadman, PA AF Whitley, CR Bounds, JA Steadman, PA TI A portable swipe monitor for alpha contamination SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO AB A portable swipe monitor has been developed at Los Alamos National Laboratory for the state of New Mexico. The monitor is intended for use at New Mexico ports of entry to detect removable alpha contamination on shipments bound for the proposed Waste Isolation Pilot Plant (WIPP). This detector uses Long-Range Alpha Detection (LRAD) technology, which monitors ionization created by alpha interactions with ambient air, and includes built-in background subtraction of external radiation fields and radon. Its sensitivity to alpha contamination is on the order of a few tens of dpm, and it has excellent linearity throughout its entire range of over 200,000 counts per minute of alpha activity. Designed to be used primarily in the field, the monitor is battery-powered and can operate continuously for up to five hours. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Natl Ctr Genome Resources, Santa Fe, NM 87505 USA. RP Whitley, CR (reprint author), Univ Calif Los Alamos Natl Lab, MS J-561, Los Alamos, NM 87545 USA. NR 4 TC 1 Z9 1 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 533 EP 535 DI 10.1109/23.682443 PG 3 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200061 ER PT J AU Richardson, JM Snow, WM Chowdhuri, Z Greene, GL AF Richardson, JM Snow, WM Chowdhuri, Z Greene, GL TI Accurate determination of thermal neutron flux via cryogenic calorimetry SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO AB Absolute determination of thermal neutron flux is an important capability for several applications including neutron dosimetry, analytical chemistry, oil recovery, nuclear waste clean-up, and the determination of the neutron lifetime. Few methods exist that are calibrated to better than similar to 0.5% accuracy. As a corollary to this statement, it is also true that few thermal neutron absorption cross sections are known to better than similar to 0.5% accuracy. Several groups, including one at the National Institute of Standards and Technology (NIST) have worked for many years to develop methods for pushing the accuracy below the 0.1% level. This paper describes a calorimetric technique which avoids many of the problems associated with absolute counting methods. A description of the calorimetric method and results of system tests will be presented. C1 Sci Res Lab, Cambridge, MA 02143 USA. Indiana Univ, Bloomington, IN 47405 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Richardson, JM (reprint author), Sci Res Lab, 15 Ward St, Cambridge, MA 02143 USA. NR 8 TC 10 Z9 10 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 550 EP 555 DI 10.1109/23.682446 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200064 ER PT J AU Li, Z Eremin, V Ilyashenko, I Ivanov, A Verbitskaya, E AF Li, Z Eremin, V Ilyashenko, I Ivanov, A Verbitskaya, E TI Investigation of epitaxial silicon layers as a material for radiation hardened silicon detectors SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO ID N-EFF AB Epitaxial grown thick layers (greater than or equal to 100 mu m) of high resistivity silicon (Epi-Si) have been investigated as a possible candidate for radiation hardened material for detectors in high-energy physics. As grown Epi-Si layers contain high concentrations (up to 2.10(12) cm(-3)) Of deep levels compared with that in standard high resistivity bulk Si. After irradiation of test diodes by protons (E-p = 24 GeV) with a fluence of 1.5.10(11) cm(-2), no additional radiation induced deep traps have been detected. A reasonable explanation is that there is a sink of primary radiation induced defects (interstitial and vacancies), possibly by as-grown defects, in epitaxial layers. :The "sinking" process, however, becomes non-effective at high radiation fluences (10(14) cm(-2)) due to saturation of epitaxial defects by high concentration of radiation induced ones. As a result, at neutron fluences of 1.10(14)cm(-2) the deep level spectrum corresponds to well-known spectrum of radiation induced defects in high resistivity bulk Si. The net effective concentration in the space charge region equals to 3.10(12) cm(-3) after 3 months of room temperature storage and reveals similar annealing behavior for epitaxial as compared to bulk silicon. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. AF Ioffe Phys Tech Inst, St Petersburg 194021, Russia. RP Li, Z (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. RI Verbitskaya, Elena/D-1521-2014; Ivanov, Alexander/E-3993-2014 NR 12 TC 9 Z9 9 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 585 EP 590 DI 10.1109/23.682453 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200071 ER PT J AU Biggeri, U Borchi, E Bruzzi, M Eremin, V Leroy, C Li, Z Menichelli, D Pirollo, S Sciortino, S Verbitskaya, E AF Biggeri, U Borchi, E Bruzzi, M Eremin, V Leroy, C Li, Z Menichelli, D Pirollo, S Sciortino, S Verbitskaya, E TI A comparative study of heavily irradiated silicon and non irradiated SI LEC GaAs detectors SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NM ID CHARGE-COLLECTION EFFICIENCY; PARTICLE DETECTORS; ELECTRON TRAPS AB Silicon p(+)n junctions irradiated with neutron and proton fluences in the range 5x10(11)-4x10(15) cm(-2) and non-irradiated SI LEC GaAs Schottky barriers have been analyzed. In silicon the concentration N-t, of the main radiation-induced deep traps (Et approximate to 0.44 - 0.54 eV) is found to increase as N-t alpha f achieving values up to 5x10(15) cm(-3) and a mobility saturation at 100cm(2)/Vs has been observed at the highest fluences. A quantitative comparison between heavily irradiated silicon and non-irradiated GaAs evidenced similar charge collection efficiencies, a quasi-intrinsic bulk and similar concentrations of deep defects. On this basis, a unique model, correlating the lattice disorder and the detector performance, is suggested. C1 Univ Florence, Dipartimento Energet S Stecco, INFN, I-50139 Florence, Italy. AF Ioffe Phys Tech Inst, St Petersburg 194021, Russia. Univ Montreal, Montreal, PQ H3C 3J7, Canada. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Univ Florence, Dipartimento Energet S Stecco, INFN, Via S Marta 3, I-50139 Florence, Italy. RI Verbitskaya, Elena/D-1521-2014; Bruzzi, Mara/K-1326-2015 OI Bruzzi, Mara/0000-0001-7344-8365 NR 18 TC 2 Z9 2 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9499 EI 1558-1578 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 597 EP 601 DI 10.1109/23.682455 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200073 ER PT J AU Bellwied, R Beuttenmuller, R Chen, W DiMassimo, D Dyke, H French, A Hall, JR Hoffmann, GW Humanic, TJ Kotov, IV Kraner, HW Li, Z Liaw, CJ Lopez, J Lynn, D Rykov, VL Pandey, SU Pruneau, C Schambach, J Sedlmeir, J Sugarbaker, E Takahashi, J Wilson, WK AF Bellwied, R Beuttenmuller, R Chen, W DiMassimo, D Dyke, H French, A Hall, JR Hoffmann, GW Humanic, TJ Kotov, IV Kraner, HW Li, Z Liaw, CJ Lopez, J Lynn, D Rykov, VL Pandey, SU Pruneau, C Schambach, J Sedlmeir, J Sugarbaker, E Takahashi, J Wilson, WK TI Studies of ionizing radiation effects on STAR silicon drift detectors SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO AB A 63 x 63mm rectangular silicon drift detector was irradiated using a Co-60 source and its performance was studied. The total accumulated dose was 23.5 krad. The detector performance after room temperature annealing was studied. The detector was found to be sufficiently radiation hard for RHIC applications. C1 Ohio State Univ, Columbus, OH 43210 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Texas, Austin, TX 78712 USA. Wayne State Univ, Detroit, MI 48202 USA. IHEP, Protvino, Russia. RP Kotov, IV (reprint author), Ohio State Univ, Columbus, OH 43210 USA. RI Takahashi, Jun/B-2946-2012 OI Takahashi, Jun/0000-0002-4091-1779 NR 9 TC 1 Z9 2 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 623 EP 625 DI 10.1109/23.682460 PG 3 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200077 ER PT J AU Abe, K Ashford, V Aston, D Bienz, T Baird, K Bird, F Cavalli-Sforza, M Coller, J Coyle, P Coyne, D Dasu, S Dunwoodie, W Dima, M Hallewell, G Hasegawa, Y Iwasaki, Y Kalelkar, M Kawahara, H Leith, DWGS Lu, A Meadows, B Muller, D McCulloch, M McShurley, D Nagamine, T Narita, S Oxoby, G Pavel, TJ Plano, R Ratcliff, B Reif, R Rensing, P Schneider, M Schultz, D Shapiro, S Shaw, H Simopoulos, C Staengle, H Stamer, P Stiles, P Toge, N Va'vra, J Weber, T Whitaker, JS Wilson, RJ Williams, D Williams, SH Willocq, S Yellin, S Yuta, H AF Abe, K Ashford, V Aston, D Bienz, T Baird, K Bird, F Cavalli-Sforza, M Coller, J Coyle, P Coyne, D Dasu, S Dunwoodie, W Dima, M Hallewell, G Hasegawa, Y Iwasaki, Y Kalelkar, M Kawahara, H Leith, DWGS Lu, A Meadows, B Muller, D McCulloch, M McShurley, D Nagamine, T Narita, S Oxoby, G Pavel, TJ Plano, R Ratcliff, B Reif, R Rensing, P Schneider, M Schultz, D Shapiro, S Shaw, H Simopoulos, C Staengle, H Stamer, P Stiles, P Toge, N Va'vra, J Weber, T Whitaker, JS Wilson, RJ Williams, D Williams, SH Willocq, S Yellin, S Yuta, H TI The performance of the barrel CRID at the SLD; Long-term operational experience SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO ID RING-IMAGING DETECTOR AB The Barrel GRID detector has been operating successfully at SLD for the past seven years. It is an important tool for SLD physics analyses. We report results based on long term operational experience of a number of important quantities such as the Cherenkov quality factor, N-0, of the device, fluid transparency, electron lifetime, single electron detection efficiency, anode wire ageing, TMAE purity, long term stability of the gas refraction index, liquid radiator transparency, Cherenkov angle resolution and the number of photoelectrons observed per ring. C1 Tohoku Univ, Sendai, Miyagi 980, Japan. SLAC, Stanford, CA USA. Rutgers State Univ, Piscataway, NJ 08855 USA. Univ Barcelona, E-08007 Barcelona, Spain. Boston Univ, Boston, MA 02215 USA. Univ Marseille, Marseille, France. UC Santa Cruz, Santa Cruz, CA USA. Univ Wisconsin, Madison, WI 53706 USA. Colorado State Univ, Ft Collins, CO 80523 USA. UC Santa Barbara, Santa Barbara, CA USA. Univ Cincinnati, Cincinnati, OH 45221 USA. RP Abe, K (reprint author), Tohoku Univ, Sendai, Miyagi 980, Japan. RI Cavalli-Sforza, Matteo/H-7102-2015; OI Wilson, Robert/0000-0002-8184-4103 NR 28 TC 2 Z9 2 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 648 EP 656 DI 10.1109/23.682601 PG 9 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200082 ER PT J AU Adam, I Aleksan, R Aston, D Bailly, P Beigbeder, C Benayoun, M Benkebil, M Bonneaud, G Breton, D Briand, H Brown, D Bourgeois, P Chauveau, J Cizeron, R Cohen-Tanugi, J Convery, M David, P de la Vaissiere, C de Lesquen, A del Buono, L Fouque, G Gaidot, A Gastaldi, F Genat, JF Gosset, L Hale, D de Monchenault, GH Hamon, O Kadel, R Kadyk, J Karolak, M Kawahara, H Krueger, H Lebbolo, H Leruste, PH Le Diberder, F London, G Long, M Lory, J Lu, A Lutz, AM Lynch, G McCulloch, M McShurley, D Malchow, R Matricon, P Mayer, B Meadows, B Narjoux, JL Noppe, JM Oshatz, D Oxoby, G Plano, R Plaszczynski, S Pripstein, M Rasson, J Ratcliff, B Reif, R Renard, C Roos, L Roussot, E Sarazin, X Schune, MH Schwiening, J Sen, S Shelkov, V Sokoloff, M Staengle, H Stiles, P Stone, R Thiebaux, C Truong, K Toki, W Vasileiadis, G Vasseur, G Va'vra, J Verderi, M Versille, S Warner, D Weber, T Weber, TF Wenzel, W Wilson, R Wormser, G Yeche, C Yellin, S Zhang, B Zito, M AF Adam, I Aleksan, R Aston, D Bailly, P Beigbeder, C Benayoun, M Benkebil, M Bonneaud, G Breton, D Briand, H Brown, D Bourgeois, P Chauveau, J Cizeron, R Cohen-Tanugi, J Convery, M David, P de la Vaissiere, C de Lesquen, A del Buono, L Fouque, G Gaidot, A Gastaldi, F Genat, JF Gosset, L Hale, D de Monchenault, GH Hamon, O Kadel, R Kadyk, J Karolak, M Kawahara, H Krueger, H Lebbolo, H Leruste, PH Le Diberder, F London, G Long, M Lory, J Lu, A Lutz, AM Lynch, G McCulloch, M McShurley, D Malchow, R Matricon, P Mayer, B Meadows, B Narjoux, JL Noppe, JM Oshatz, D Oxoby, G Plano, R Plaszczynski, S Pripstein, M Rasson, J Ratcliff, B Reif, R Renard, C Roos, L Roussot, E Sarazin, X Schune, MH Schwiening, J Sen, S Shelkov, V Sokoloff, M Staengle, H Stiles, P Stone, R Thiebaux, C Truong, K Toki, W Vasileiadis, G Vasseur, G Va'vra, J Verderi, M Versille, S Warner, D Weber, T Weber, TF Wenzel, W Wilson, R Wormser, G Yeche, C Yellin, S Zhang, B Zito, M TI DIRC, the internally reflecting ring imaging Cherenkov detector for BABAR SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO AB The DIRC is a new type of Cherenkov imaging device that will be used for the first time in the BABAR detector at the asymmetric B-factory, PEP-II. It is based on total internal reflection and uses long, rectangular bars made from synthetic fused silica as Cherenkov radiator and light guide. The principles of the DIRC ring imaging Cherenkov technique are explained and results from the prototype program are presented. Its choice for the BABAR detector particle identification system is motivated, followed by a discussion of the quartz radiator properties and the detector design. C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. CE Saclay, DAPNIA, CEA, F-91191 Gif Sur Yvette, France. Univ Paris 06, LPNHE, F-75252 Paris, France. Univ Paris 07, LPNHE, F-75252 Paris 05, France. Univ Paris Sud, LAL Orsay, F-91405 Orsay, France. Ecole Polytech, LPNHE, F-91128 Palaiseau, France. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Colorado State Univ, Dept Phys, Ft Collins, CO 80523 USA. Univ Cincinnati, Dept Phys, Cincinnati, OH 45221 USA. Rutgers State Univ, Dept Phys, Piscataway, NJ 08855 USA. Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China. RP Adam, I (reprint author), Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. OI Hamel de Monchenault, Gautier/0000-0002-3872-3592; Wilson, Robert/0000-0002-8184-4103 NR 13 TC 11 Z9 11 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 657 EP 664 DI 10.1109/23.682602 PG 8 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200083 ER PT J AU Field, RC Frey, R Woods, M Arodzero, A Zhou, J AF Field, RC Frey, R Woods, M Arodzero, A Zhou, J TI Measurement of electron beam polarization from the energy asymmetry of Compton scattered photons SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO AB We describe a new method for precision measurement (similar to 1%) Of the longitudinal polarization of high-energy electron beams. The method relies on measuring the energy asymmetry of Compton scattered photons which result from collisions between the electron beam and a polarized laser beam. The measurement takes place near the electron-positron interaction point at the SLAG Linear Collider (SLC). The detector described here (PGC) is a threshold gas Cherenkov device which follows a lead radiator. The Cherenkov threshold (14 MeV) is essential for eliminating enormous synchrotron radiation-induced backgrounds at the position of interest in the SLC. We also describe the calibration of the PGC energy response in a test beam and its performance as a working polarimeter for the SLC/SLD physics program. Preliminary results from the 1996 run indicate that PGC measurement with total error at or below the 1% level is indeed achievable, and hence serves as a valuable crosscheck of the polarization scale. C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Univ Oregon, Dept Phys, Eugene, OR 97403 USA. RP Field, RC (reprint author), Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 8 TC 4 Z9 4 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 670 EP 675 DI 10.1109/23.682610 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200085 ER PT J AU Amman, M Beaulieu, L Hong, WS Phair, L Walton, JT Wozniak, GJ AF Amman, M Beaulieu, L Hong, WS Phair, L Walton, JT Wozniak, GJ TI Heavy ion response of amorphous silicon transmission detectors for particle identification SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO ID IONIZING PARTICLES; CHARGED-PARTICLES; LAYERS AB In an effort to determine the applicability of a-Si:H transmission detectors to integrated Delta E-E detector telescopes, we have measured the response of discrete a-Si:H detectors to ions with atomic numbers between 7 and 36 and ranging in energy from 0.5 to 4.5 MeV/nucleon. Measured pulse height. spectra show substantial pulse height deficits which depend on detector bias. Additionally an unexpected result is obtained in that the amplitudes of the detector signals correlate better with the total ion energy than with the ion energy loss in the transmission detector. C1 Ernest Orlando Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Amman, M (reprint author), Ernest Orlando Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RI Beaulieu, Luc/A-6803-2009 OI Beaulieu, Luc/0000-0003-0429-6366 NR 17 TC 0 Z9 0 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 676 EP 680 DI 10.1109/23.682611 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200086 ER PT J AU Zhu, RY Deng, Q Newman, H Woody, CL Kierstead, JA Stoll, SP AF Zhu, RY Deng, Q Newman, H Woody, CL Kierstead, JA Stoll, SP TI A study on the radiation hardness of lead tungstate crystals SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO ID DAMAGE AB This report presents recent progress of a study on the radiation damage in lead tungstate (PbWO4) crystals. The dose rate dependence of radiation damage in PbWO4 has been observed. An optimization of the oxygen compensation through post-growth thermal annealing has led to PbWO4 samples with significantly improved radiation hardness. Front irradiation is found to cause a factor of 2 to 6 times less severe damage than uniform irradiation. Lanthanum doping was found not to be a determining factor for PbWO4 radiation hardness improvement. Finally, a TEM/EDS analysis revealed that the radiation damage in PbWO4 crystals is caused by oxygen vacancies. C1 CALTECH, Pasadena, CA 91125 USA. Chinese Acad Sci, Shanghai Inst Ceram, Shanghai 200050, Peoples R China. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Zhu, RY (reprint author), CALTECH, 256-48 HEP, Pasadena, CA 91125 USA. NR 11 TC 33 Z9 38 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 686 EP 691 DI 10.1109/23.682613 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200088 ER PT J AU David, G Goto, Y Kistenev, E Stoll, S White, S Woody, C Bazilevsky, A Belikov, S Chernichenkov, S Denisov, A Kochetkov, V Melnikov, Y Onuchin, V Semenov, V Shelikhov, V Soldatov, A Usachev, A AF David, G Goto, Y Kistenev, E Stoll, S White, S Woody, C Bazilevsky, A Belikov, S Chernichenkov, S Denisov, A Kochetkov, V Melnikov, Y Onuchin, V Semenov, V Shelikhov, V Soldatov, A Usachev, A TI The PHENIX lead-scintillator electromagnetic calorimeter: Test beam and construction experience SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO AB We have recently completed the production of the 15552 channel Lead-Scintillator Electromagnetic calorimeter for the PHENIX experiment at RHIC. Our design features a single 4 tower module which is repeated throughout and which was produced with a number of quality control steps designed to achieve consistent, large light yields in all channels. We present results on the uniformity of the calorimeter, accuracy of a cosmic muon based precalibration scheme and test beam performance. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Inst High Energy Phys, Protvino, Russia. RP David, G (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. RI Semenov, Vitaliy/E-9584-2017 NR 4 TC 8 Z9 8 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 692 EP 697 DI 10.1109/23.682617 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200089 ER PT J AU Marchant, J Baumbaugh, B Gerig, A Hurlbut, C Kauffman, J Pla-Dalmau, A Reynolds, K Ruchti, R Warchol, J Wayne, M Zheng, H AF Marchant, J Baumbaugh, B Gerig, A Hurlbut, C Kauffman, J Pla-Dalmau, A Reynolds, K Ruchti, R Warchol, J Wayne, M Zheng, H TI Development of new scintillator and waveshifter materials SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO AB Experimental applications requiring fast timing and/or high efficiency position and energy measurements typically use scintillation materials. Scintillators utilized for triggering, tracking,and calorimetry in colliding beam detectors are vulnerable to the high radiation fields associated with such experiments. We have begun an investigation of several fluorescent dyes which might lead to fast, efficient, and radiation resistant scintillators. Preliminary results of spectral analysis and efficiency are presented. C1 Univ Notre Dame, Notre Dame, IN 46556 USA. Ludlum Measurements Inc, Sweetwater, TX 79556 USA. Philadelphia Coll Pharm & Sci, Philadelphia, PA 19104 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Marchant, J (reprint author), Univ Notre Dame, Notre Dame, IN 46556 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 698 EP 704 DI 10.1109/23.682618 PG 7 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200090 ER PT J AU David, G Kistenev, E Stoll, S White, S Woody, C Bazilevsky, A Belikov, S Chernichenkov, S Denisov, A Gilitzky, Y Kochetkov, V Melnikov, Y Onuchin, V Semenov, A Shelikhov, V Soldatov, A AF David, G Kistenev, E Stoll, S White, S Woody, C Bazilevsky, A Belikov, S Chernichenkov, S Denisov, A Gilitzky, Y Kochetkov, V Melnikov, Y Onuchin, V Semenov, A Shelikhov, V Soldatov, A TI The calibration and monitoring system for the PHENIX lead-scintillator electromagnetic calorimeter SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO AB The calibration and monitoring system for the PHENIX lead-scintillator electromagnetic calorimeter is described along with the experience obtained in using this system to calibrate calorimeter modules with cosmic rays. The system is based on a UV laser which delivers light to each module through a series of optical fibers and splitters that is monitored at various points using silicon and vacuum photodiodes. Results are given from a prototype system based on a nitrogen laser which was used to monitor the stability of several modules, as well as to set the gains of the phototubes and establish the energy calibration of all calorimeter modules before installation into the final detector. A description of the final system to be used in PHENIX, based on a high power YAG laser, is also given. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Inst High Energy Phys, Protvino, Russia. RP David, G (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. NR 4 TC 10 Z9 10 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 705 EP 709 DI 10.1109/23.682619 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200091 ER PT J AU Paulus, MJ Mihalczo, JT Valentine, TE Mullens, JA Breeding, JE Uckan, T Mattingly, J Turner, G Smith, MC McEvers, JA AF Paulus, MJ Mihalczo, JT Valentine, TE Mullens, JA Breeding, JE Uckan, T Mattingly, J Turner, G Smith, MC McEvers, JA TI A novel method for determining pulse counting circuitry dead time using the Nuclear Weapons Inspection System SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO AB A novel method for measuring dead time in nuclear pulse processing circuitry has been developed using the autocorrelation measurement capability of the Nuclear Weapons Inspection System (NWIS). Initially developed for active neutron interrogation of nuclear weapons and other fissile assemblies, NWIS employs a custom gallium arsenide application specific integrated circuit and a new signature analysis software package to simultaneously acquire and display the autocorrelation and cross-correlation spectra of up to five detector/electronics systems. The system operates at clock frequencies up to I GHz, permitting the collection of timing pulses in bins as narrow as I ns. In normal operation NWIS uses well characterized detectors and constant fraction discriminators, but it may also be configured to accept pulses from any circuit and to use the autocorrelation spectrum to accurately determine dead-time. Unlike traditional dead-time assessment techniques that typically require multiple sources and an assumed dead-time model, NWIS provides single-measurement assessment of circuit dead time and does not require an assumed dead-time model or a calibrated high count-rate source. C1 Oak Ridge Natl Lab, Div Instrumentat & Controls, Oak Ridge, TN 37830 USA. RP Paulus, MJ (reprint author), Oak Ridge Natl Lab, Div Instrumentat & Controls, POB 2008, Oak Ridge, TN 37830 USA. OI Valentine, Timothy/0000-0001-7495-7348 NR 2 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 710 EP 714 DI 10.1109/23.682620 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200092 ER PT J AU Krieger, B Kipnis, I Ludewigt, BA AF Krieger, B Kipnis, I Ludewigt, BA TI XPS: A multi-channel preamplifier-shaper IC for x-ray spectroscopy SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO ID CONTINUOUS-TIME FILTER; DESIGN AB An integrated circuit featuring 48 channels of charge-sensitive preamplifiers followed by variable-gain pulse shaping amplifiers is being developed as part of an x-ray spectrometer with a highly segmented detector to handle high fluxes in synchrotron experiments. Such detector systems can provide excellent energy resolution combined with one-dimensional spatial information. The IC combines many basic spectroscopy amplifier functions with a low-noise preamplifier section to produce a unique circuit capable of driving conventional ADC modules directly. An important feature of the design is the novel CR-RC2 pulse shaper. In this section, high-linearity transconductor circuits are required in order to provide a broad range of continuously variable peaking times while still maintaining the linearity and noise performance necessary for x-ray spectroscopy. Reported here are first measurements made on the performance of a 16-channel prototype integrated circuit. At present, the preamplifier-shaper circuit achieves an equivalent input noise of 26 electrons rms at 2 mu s peaking time with a 0.2 pF external capacitor, which is similar to the capacitance of a single detector element. The design was fabricated in standard 1.2 mu m CMOS technology.(1). C1 Ernest Orlando Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Hewlett Packard Co, Newark, CA 94560 USA. RP Krieger, B (reprint author), Ernest Orlando Lawrence Berkeley Natl Lab, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 7 TC 14 Z9 14 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 732 EP 734 DI 10.1109/23.682625 PG 3 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200097 ER PT J AU Pengg, F AF Pengg, F TI Pixel detector readout electronics with two-level discriminator SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO AB In preparation for a silicon pixel detector with more than 3000 readout channels per chip for operation at the future large hadron collider (LHC) at CERN the analog frontend of the readout electronics has been designed and measured on several test-arrays with 16 by 4 cells. They are implemented in the HP 0.8 mu m process but compatible with the design rules of the radiation hard Honeywell 0.8 mu m bulk process. Each call contains bump bonding pad, preamplifier, discriminator and control logic for masking and testing within a layout area of only 50 mu m by 140 mu m. A new two-level discriminator scheme has been implemented to cope with the problems of time-walk and interpixel cross-coupling. The measured gain of the preamplifier is 900mV for a minimum ionizing particle (MIP, about 24000 e(-) for a 300 mu m thick Si-detector) with a return to baseline within 750ns for a 1MIP input signal. The full readout chain (without detector) shows an equivalent noise charge of 60e(-) r.m.s. The time-walk, a function of the separation between the two threshold levels, is measured to be 22ns at a separation of 1500e(-), which is adequate for the 40MHz beam-crossing frequency at the LHC. The interpixel cross-coupling, measured with a 40fF coupling capacitance, is less than 3%. A single cell consumes 35 mu W at 3.5V supply voltage. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Pengg, F (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. NR 7 TC 2 Z9 2 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 745 EP 750 DI 10.1109/23.682628 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200100 ER PT J AU Bryan, WL Jagadish, U Britton, CL Frank, SS Ericson, MN Simpson, ML Young, GR Clonts, LG Smith, RS Oskarsson, A Mark, T O'Brien, E Greene, V AF Bryan, WL Jagadish, U Britton, CL Frank, SS Ericson, MN Simpson, ML Young, GR Clonts, LG Smith, RS Oskarsson, A Mark, T O'Brien, E Greene, V TI TGLD: A 16-channel charge readout chip for the PHENIX pad chamber detector subsystem at RHIC SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO AB This paper describes TOLD, a charge readout chip for the PHENIX Pad Chamber (PC) subsystem at Brookhaven National Laboratory's Relativistic Heavy Ion Collider (RHIC) in Upton, NY. Due to the PC's high channel density, the TOLD and associated circuitry operate within the active detector region as permanent, zero access components, with remote set-up and test during collider operation. The TGLD design accommodates varying pad capacitance and charge gain for three detector subassemblies that detect particles at three different distances from the PHENIX collision vertex. The design also provides adjustable discrimination thresholds from MIP/10 to 2 MIP (Minimum Ionizing Particle). Three TGLD chips operate with a complimentary digital memory unit (DMU) to form 48 channel low power, low mass, readout cards. Partitioning of readout electronics and address control for robust remote operation are discussed. Component and system test results are also reported. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. IBM, Res Triangle Pk, NC USA. Univ Lund, Lund, Sweden. McGill Univ, Montreal, PQ, Canada. Brookhaven Natl Lab, Upton, NY 11973 USA. Vanderbilt Univ, Nashville, TN USA. RP Bryan, WL (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Simpson, Michael/A-8410-2011 OI Simpson, Michael/0000-0002-3933-3457 NR 4 TC 4 Z9 4 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 754 EP 757 DI 10.1109/23.682630 PG 4 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200102 ER PT J AU Wintenberg, AL Moscone, CG Jones, JP Young, GR AF Wintenberg, AL Moscone, CG Jones, JP Young, GR TI A CMOS integrating amplifier for the PHENIX Ring Imaging Cherenkov detector SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO AB A CMOS integrating amplifier has been developed for use in the PHENIX Ring Imaging Cherenkov (RICH) detector. The amplifier, consisting of a charge-integrating amplifier followed by a variable gain amplifier (VGA), is an element of a photon measurement system comprising a photomultiplier tube, a wideband, gain-of-10 amplifier, the integrating amplifier, and an analog memory followed by an ADC and double correlated sampling implemented in software. The integrating amplifier is designed for a nominal full scale input of 160 pC with a gain of 20 mV/pC and a dynamic range of 1000:1. The VGA is used for equalizing gains prior to forming analog sums for trigger purposes. The gain of the VGA is variable over a 3:1 range using a 5-bit digital control, and the risetime is held to approximately 20 ns using switched compensation in the VGA. Details of the design and results from several prototype devices fabricated in 1.2 mu m Orbit CMOS are presented. A complete noise analysis of the integrating amplifier and the correlated sampling process is included as well as a comparison of calculated, simulated and measured results. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Tennessee, Knoxville, TN 37996 USA. RP Wintenberg, AL (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 4 TC 5 Z9 5 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 758 EP 763 DI 10.1109/23.682631 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200103 ER PT J AU Cancelo, G Mayosky, M AF Cancelo, G Mayosky, M TI A parallel analog signal processing unit based on radial basis function networks SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO AB This paper reports the design of an analog neuron circuit with Gaussian activation functions. The circuit is intended to be used for parallel computation of spatial distributed signals like the ones from array sensors (e.g. detectors) and images. The importance of the model is discussed in the context of Radial Basis Function and Regularization theory. Analog hardware implementation is performed as a natural approach for massive parallel computation of radial basis functions. Gaussian unit equations and simulation plots are provided along with an analysis of adjustable parameters. C1 Univ La Plata, Fermilab, Batavia, IL 60510 USA. RP Cancelo, G (reprint author), Univ La Plata, Fermilab, POB 500,MS 368, Batavia, IL 60510 USA. NR 16 TC 1 Z9 1 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 792 EP 797 DI 10.1109/23.682638 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200110 ER PT J AU Landis, DA Madden, NW Goulding, FS AF Landis, DA Madden, NW Goulding, FS TI Bipolar pulsed reset for AC coupled charge-sensitive preamplifiers SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO AB A new type of charge restoration is described for use particularly in germanium gamma-ray spectrometers for accelerator and space physics applications. A bipolar pulsed reset technique is applied to these applications for the first time. This technique overcomes the problems introduced by the need here to AC couple detectors and the fact that very large energy depositions occur due to charged particles present in substantial fluxes, particularly in space. The circuit is described and experimental results are presented and discussed. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Engn, Engn Sci Dept,Measurement Sci Grp, Berkeley, CA 94720 USA. RP Landis, DA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Engn, Engn Sci Dept,Measurement Sci Grp, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 805 EP 809 DI 10.1109/23.682641 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200113 ER PT J AU Ericson, MN Allen, MD Boissevain, J Britton, CL Emery, MS Hahn, SF Kapustinsky, JS Lind, RE Musrock, MS Simon-Gillo, J Smith, DE Sullivan, JP Van Hecke, H Young, GR Smith, MC AF Ericson, MN Allen, MD Boissevain, J Britton, CL Emery, MS Hahn, SF Kapustinsky, JS Lind, RE Musrock, MS Simon-Gillo, J Smith, DE Sullivan, JP Van Hecke, H Young, GR Smith, MC TI Front-end module readout and control electronics for the PHENIX Multiplicity Vertex Detector SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO ID ANALOG AB Front-end module (FEM) readout and control are implemented as modular, high-density, reprogrammable functions in the PHENIX Multiplicity Vertex Detector. FEM control is performed by the heap manager, an FPGA-based circuit in the FEM unit. Each FEM has 256 channels of front-end electronics, readout, and control, all located on an MCM. Data readout, formatting, and control are performed by the heap manager along with 4 interface units that reside outside the MVD detector cylinder. This paper discusses the application of a generic heap manager and the addition of 4 interface module types to meet the specific control and data readout needs of the MVD. Unit functioning, interfaces, control timing, data format, and communication rates will be Fiber discussed in detail. Tn addition, subsystem issues regarding mode control, serial architecture and functions, error handling, Global and FPGA implementation and programming will be presented. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Tennessee, Knoxville, TN 37996 USA. RP Ericson, MN (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 8 TC 3 Z9 3 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 833 EP 837 DI 10.1109/23.682646 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200118 ER PT J AU Hubbard, GS Binder, AB Feldman, W AF Hubbard, GS Binder, AB Feldman, W TI The Lunar Prospector Discovery mission: Mission and measurement description SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO AB Lunar Prospector, the first competitively selected planetary mission in NASA's Discovery Program, is described with emphasis on the radiation spectrometer instrumentation and anticipated scientific data return. Scheduled to be launched in January 1998, the mission will conduct a one year orbital survey of the Moon's composition and structure. The suite of five instruments are outlined: neutron spectrometer, alpha particle spectrometer, gamma-ray spectrometer, electron reflectometer and magnetometer. Scientific requirements and measurement approach to detect water/ice to a sensitivity of 50 ppm (hydrogen), measure key elemental constituents, detect radioactive gas release events and accurately map the Moon's gravitational and magnetic fields are given. A brief overview of the programmatic accomplishments in meeting a tightly constrained schedule and budget is also provided. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Hubbard, GS (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 5 TC 3 Z9 3 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 880 EP 887 DI 10.1109/23.682655 PG 8 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200127 ER PT J AU Truscott, PR Evans, HE Dyer, CS Cosby, M Knight, PR Moss, CE AF Truscott, PR Evans, HE Dyer, CS Cosby, M Knight, PR Moss, CE TI Monte Carlo simulation of induced radioactive background in gamma-ray detector materials SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO AB Induced activation in detector materials constitutes a major source or background for space-borne gamma-ray instruments. Future detector systems will utilise a variety of background reduction techniques and novel detector materials to maximise signal-to-noise and resolution of the measurements taken, and assessment of the merits of different designs will require detailed attention to a wide range of physical processes. The Integrated Radiation Transport Suite (IRTS) has been applied to simulate the effects of spacecraft shielding against Van Alien and galactic cosmic-ray protons, the production of secondary hadrons, and induced radioactivity in and the response of gamma-ray detector materials. This paper discusses the physics requirements for these simulations, and the degree of success of The models through comparisons with experimental data obtained from Space Shuttle flights and proton-beam irradiation of detector materials. C1 Def Evaluat & Res Agcy, Dept Space, Farnborough GU14 0LX, Hants, England. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Truscott, PR (reprint author), Def Evaluat & Res Agcy, Dept Space, Farnborough GU14 0LX, Hants, England. NR 17 TC 1 Z9 1 U1 1 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1998 VL 45 IS 3 BP 894 EP 902 DI 10.1109/23.682657 PG 9 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ZU096 UT WOS:000074161200129 ER PT J AU Tavora, LMN Morgado, RE Estep, RJ Rawool-Sullivan, M Gilboy, WB Morton, EJ AF Tavora, LMN Morgado, RE Estep, RJ Rawool-Sullivan, M Gilboy, WB Morton, EJ TI One-sided imaging of large, dense objects using 511-keV photons from induced-pair production SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1997 Nuclear Science Symposium CY NOV 09-15, 1997 CL ALBUQUERQUE, NEW MEXICO ID FAST-NEUTRON ANALYSIS; INSPECTION SYSTEM; PFNA AB This work investigates the use of annihilation photons from gamma-ray-induced electron-positron pair production to inspect objects when only one side is accessible. The Z(2)-dependence of the pair-production cross section and the high penetration of 511-keV photons allow this method to differentiate high-Z materials in low-Z matrices. The experimental results for the dependence of the back-streaming photon yield on Z shows a factor of 20 increase for elements over the range 4 orientation relationship out of a limited spectrum of preferentially formed nucleus orientations. Accordingly, recrystallization textures can be modeled by the multiplication of a function f(g)(nucl) describing the probability of nucleation of the various orientations with a function f(g)(grow) representing their growth probability. Whereas the growth probability can be accounted for by a 40 degrees < 111 > transformation of the rolling texture, the nucleation probability of the respective grains is given by the distribution of potential nucleus orientations, which is known from local texture analysis of rolled aluminum alloys to be cube bands, grain boundaries, and second-phase particles. The contributions of these nucleation sites are determined according to an approach to calculate the number of nuclei forming at each site, which is based on microstructural investigations of the evolution of the various nucleation sites during deformation. This article describes the model for recrystallization texture simulation in aluminum alloys and gives examples of recrystallization textures of AA3004 deformed in plane-strain compression at different deformation temperatures and strain rates. C1 Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. RP Engler, O (reprint author), Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, MS K765, Los Alamos, NM 87545 USA. EM engler@lanl.gov NR 36 TC 24 Z9 24 U1 0 U2 9 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 USA SN 1047-4838 J9 JOM-J MIN MET MAT S JI JOM-J. Miner. Met. Mater. Soc. PD JUN PY 1998 VL 50 IS 6 BP 23 EP 27 DI 10.1007/s11837-998-0123-y PG 5 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing SC Materials Science; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing GA ZT013 UT WOS:000074038900003 ER PT J AU Citterio, M Manfredi, PF AF Citterio, M Manfredi, PF TI Cryogenic behavior of low-noise monolithic preamplifiers using a JFET as a front-end element SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT 3rd European Workshop on Low Temperature Electronics (WOLTE 3) CY JUN 24-26, 1998 CL SAN MINIATO, ITALY ID RADIATION; CALORIMETRY; ELECTRONICS; TECHNOLOGY; DEVICES AB The noise behavior of monolithic preamplifiers using JFETs as input elements has been investigated on a broad temperature range, from room temperature down to 77 K. The preamplifiers under study are charge integrators intended for use with radiation detectors. The parameter of dominant interest in the analysis is the equivalent noise charge (ENC). The investigation addresses two issues. One is the ENC dependence on temperature. The other one is the extent to which ENC is affected when the preamplifiers are irradiated in cryogenic conditions. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Brookhaven Natl Lab, Upton, NY 11973 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 1155-4339 J9 J PHYS IV JI J. Phys. IV PD JUN PY 1998 VL 8 IS P3 BP 155 EP 159 DI 10.1051/jp4:1998334 PG 5 WC Physics, Multidisciplinary SC Physics GA ZZ686 UT WOS:000074756500035 ER PT J AU Castaing, J Rodriguez, AD AF Castaing, J Rodriguez, AD TI Grain dimensions and high temperature creep of materials SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT 40th INSTN Colloquium on Metallurgy - Mechanical Behavior and Scale Effects CY JUN 24-26, 1997 CL PARIS, FRANCE SP INSTN ID MECHANICAL-PROPERTIES; SUPERPLASTICITY; PLASTICITY; DIFFUSION; CERAMICS AB For most mechanisms of plastic deformation the flow stress, or the creep rate, is related to the dimension of the grains. In this paper we describe a few examples of behaviour of fine grain metallic materials and ceramics which are hardest for largest grain size. Based on experimental results, we give a brief description of a few models which explain the observations. C1 Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. Univ Sevilla, Dept Fis Mat Condensada, E-41080 Seville, Spain. RP Castaing, J (reprint author), Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, MS K765,POB 1663, Los Alamos, NM 87545 USA. OI Dominguez-Rodriguez, Arturo/0000-0003-1598-5669 NR 31 TC 0 Z9 0 U1 0 U2 0 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 1155-4339 J9 J PHYS IV JI J. Phys. IV PD JUN PY 1998 VL 8 IS P4 BP 195 EP 202 DI 10.1051/jp4:1998424 PG 8 WC Physics, Multidisciplinary SC Physics GA ZZ688 UT WOS:000074756700025 ER PT J AU Kirschner, DE Mehr, R Perelson, AS AF Kirschner, DE Mehr, R Perelson, AS TI Role of the thymus in pediatric HIV-1 infection SO JOURNAL OF ACQUIRED IMMUNE DEFICIENCY SYNDROMES LA English DT Article DE thymus; AIDS; ordinary differential equations; immunology; HIV; pediatric AIDS; mathematical modeling ID HUMAN-IMMUNODEFICIENCY-VIRUS; CD4+ T-CELLS; LYMPHOCYTES; THYMOCYTES; INFANTS; MOUSE; MICROENVIRONMENT; PATHOGENESIS; CHILDREN; DYNAMICS AB Several lines of evidence suggest that HIV-1 is present in the thymus during HIV-1 infection. Precursors to mature CD4(+) T lymphocytes develop in the thymus, which suggests that thymic infection may play a role in the CD4(+) T-cell decline observed during the course of pediatric HIV-1 infection. We illustrate, through mathematical modeling, the potential effects of thymic infection on the course of pediatric AIDS disease progression. We find that infection in the thymus not only can supplement peripheral infection but can help explain the faster progression in pediatric cases, as well as the early and high viral burden. C1 Univ Michigan, Sch Med, Dept Microbiol, Ann Arbor, MI USA. Princeton Univ, Dept Mol Biol, Princeton, NJ 08544 USA. Los Alamos Natl Lab, Div Theoret, Los Alamos, NM USA. RP Kirschner, DE (reprint author), Univ Michigan, Sch Med, Dept Microbiol & Immunol, 6730 Med Sci 2, Ann Arbor, MI 48109 USA. EM kirschne@umich.edu FU NCRR NIH HHS [RR06555]; NIAID NIH HHS [AI28433] NR 64 TC 35 Z9 36 U1 0 U2 2 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 1525-4135 J9 J ACQ IMMUN DEF SYND JI J. Acquir. Immune Defic. Syndr. PD JUN 1 PY 1998 VL 18 IS 2 BP 95 EP 109 PG 15 WC Immunology; Infectious Diseases SC Immunology; Infectious Diseases GA ZU166 UT WOS:000074168900001 PM 9637574 ER PT J AU Weber, RJ Stolzenburg, MR Pandis, SN McMurry, PH AF Weber, RJ Stolzenburg, MR Pandis, SN McMurry, PH TI Inversion of ultrafine condensation nucleus counter pulse height distributions to obtain nanoparticle (similar to 3-10 nm) size distributions SO JOURNAL OF AEROSOL SCIENCE LA English DT Article ID PARTICLE COUNTER AB Previous work (Ahn and Liu (1990) J. Aerosol. Sci. 21, 249-261; Brockmann (1981) Ph.D. Thesis, University of Minnesota; Rebours et al. (1992) J. Aerosol. Sci. 23, S189-S192; Stolzenburg (1988) Ph.D. thesis, University of Minnesota) has shown that for particles smaller than about 15 nm, pulse heights produced by the optical detector in a white-light ultrafine condensation nucleus counter (UCNC; Stolzenburg and McMurry (1991) Aerosol. Sci. 'Technol. 14, 48-65) decrease with initial particle size. We have previously reported on the use of pulse heights from this instrument to determine the concentrations of freshly nucleated atmospheric nanoparticles in the 3-4 nm diameter range (Weber et al. (1995) J. Atm. Sci. 52, 2242-2257) Weber et al. (1997) J. Geophys. Res. 102, 4375-4385). In this paper we report on the inversion of measured pulse-height distributions to obtain size distributions of particles in the 3-10 nm diameter range. Using methods developed by Stolzenburg (Stolzenburg (1988) Ph.D. Thesis, University of Minnesota) the effect of diffusional broadening is taken into account so as to obtain monodisperse kernel functions from measured pulse-height distributions produced by DMA-generated calibration aerosols in the 3-50 nm diameter range. These kernel functions are then used with the MICRON algorithm described by Wolfenbarger and Seinfeld (1990, J. Aerosol. Sci. 21, 227-247) to obtain size distributions of nanoparticle aerosols from measured pulse height distributions. Calculations were done to ensure that assumed pulse-height data generated from selected known size distributions can be inverted to recover the original size distribution. Results from these validation studies are discussed. Applications of the inversion algorithm to data acquired in studies of homogeneous nucleation in the atmosphere are also presented. Published by Elsevier Science Ltd. C1 Brookhaven Natl Lab, Environm Chem Div, Upton, NY 11973 USA. Aersol Dynam Inc, Albany, CA 94710 USA. Carnegie Mellon Univ, Dept Chem Engn, Pittsburgh, PA 15213 USA. Univ Minnesota, Dept Mech Engn, Particle Technol Lab, Minneapolis, MN 55455 USA. RP Weber, RJ (reprint author), Brookhaven Natl Lab, Environm Chem Div, Bldg 815E, Upton, NY 11973 USA. RI Pandis, Spyros/D-3680-2013; McMurry, Peter/A-8245-2008; OI McMurry, Peter/0000-0003-1609-5131; Pandis, Spyros/0000-0001-8085-9795 NR 22 TC 33 Z9 33 U1 0 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0021-8502 J9 J AEROSOL SCI JI J. Aerosol. Sci. PD JUN-JUL PY 1998 VL 29 IS 5-6 BP 601 EP 615 DI 10.1016/S0021-8502(97)10026-X PG 15 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA ZT632 UT WOS:000074107300010 ER PT J AU Czernik, S Elam, CC Evans, RJ Meglen, RR Moens, L Tatsumoto, K AF Czernik, S Elam, CC Evans, RJ Meglen, RR Moens, L Tatsumoto, K TI Catalytic pyrolysis of nylon-6 to recover caprolactam SO JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS LA English DT Article DE nylon-6; caprolactam; depolymerization; catalytic pyrolysis; molecular-beam mass-spectrometry; fluidized bed reactor; plastics recycling ID THERMAL-DEGRADATION; POLYMERS AB Catalytic pyrolysis has been proposed as a possible process for the recovery of caprolactam from waste nylon-6. Promising process conditions, i.e. catalyst and temperature were identified using a micro-scale reactor/molecular-beam mass-spectrometer system. At 330-360 degrees C, in the presence of alpha-alumina supported KOH, the reaction proceeded at a high rate and selectivity. Only a few minutes were needed to complete the nylon-6 depolymerization with a caprolactam yield of 85%. These results were confirmed in a bench-scale fluidized bed reactor system. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Czernik, S (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. NR 21 TC 26 Z9 26 U1 1 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-2370 J9 J ANAL APPL PYROL JI J. Anal. Appl. Pyrolysis PD JUN PY 1998 VL 46 IS 1 BP 51 EP 64 DI 10.1016/S0165-2370(98)00068-0 PG 14 WC Chemistry, Analytical; Spectroscopy SC Chemistry; Spectroscopy GA ZY376 UT WOS:000074614900004 ER PT J AU Johnson, L Schwartz, LM Elata, D Berryman, JG Hornby, B Norris, AN AF Johnson, L Schwartz, LM Elata, D Berryman, JG Hornby, B Norris, AN TI Linear and nonlinear elasticity of granular media: Stress-induced anisotropy of a random sphere pack SO JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME LA English DT Article ID VELOCITY ANISOTROPY; MODULI; ROCKS AB We develop an effective medium theory of the nonlinear elasticity of a random sphere pack based upon the underlying Hertz-Mindlin theory of grain-grain contacts. We compare our predictions for the stress-dependent sound speeds against new experimental data taken on samples with stress-induced uniaxial anistropy. We show that the second-order elastic moduli, C-ijkl, and therefore the sound speeds, can be calculated as unique path-independent functions of an arbitrary strain environment, {epsilon(kl)}, thus generalizing earlier results due to Walton. However, the elements of the stress tensor, oil, are not unique functions of {epsilon(kl)} and their values depend on the strain path. Consequently, the sound speeds, considered as functions of the applied stresses, are path dependent. Illustrative calculations for three cases of combined hydrostatic and uniaxial strain are presented. We show further, that, even when the additional applied uniaxial strain is small, these equations are not consistent with the usual equations of third-order hyperelasticity. Nor should they be, for the simple reason that there does not exist an underlying energy function which is simply a function of the current state of the strain. Our theory provides a good understanding of our new data an sound speeds as a function of uniaxial stress. C1 Schlumberger Doll Res Ctr, Ridgefield, CT 06877 USA. Univ Calif Lawrence Livermore Natl Lab, Div Earth Sci, Livermore, CA 94551 USA. Schlumberger Cambridge Res Ltd, Cambridge CB3 0EL, England. Rutgers State Univ, Dept Aerosp & Mech Engn, Piscataway, NJ 08855 USA. RP Johnson, L (reprint author), Schlumberger Doll Res Ctr, Old Quarry Rd, Ridgefield, CT 06877 USA. RI Berryman, James/A-9712-2008; Norris, Andrew/B-1821-2008; OI Norris, Andrew/0000-0001-7577-3698; Elata, David/0000-0002-3816-6669 NR 29 TC 12 Z9 12 U1 2 U2 5 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0021-8936 J9 J APPL MECH-T ASME JI J. Appl. Mech.-Trans. ASME PD JUN PY 1998 VL 65 IS 2 BP 380 EP 388 PG 9 WC Mechanics SC Mechanics GA ZZ804 UT WOS:000074768800013 ER PT J AU Keer, LM Xu, YL Luk, VK AF Keer, LM Xu, YL Luk, VK TI Boundary effects in penetration or perforation SO JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME LA English DT Article AB For the analysis of stress distributions around a projectile tip in penetration or perforation, a point force P associated with an expansion source E-z, which depends on the geometry of the projectile, is employed to simulate the projectile. Using the method of half-space analysis by Mindlin (1936), the boundary effects on the projectile are analyzed. The analytical solutions of an expansion source associated with a concentrated force are derived for the prediction of the damage zones in a target as the projectile either approaches or leaves the boundary. As a projectile perforates a target, it forms a cratering area at the impact surface and leaves a cone-like spalling area at the exit. surface. The presence of these two areas and the fact that the spalling area is larger than the cratering area in perforation, can be explained by the stress analysis of boundary effects. Solution of the cavity expansion source in a half-space is derived. This solution provides a theoretical evidence for the conclusion obtained from the empirical analysis by Forrestal et al. (1994), Their conclusion states that when the projectile is at about twice its shank diameters, it can be approximately treated as though it were in the infinite medium. C1 Northwestern Univ, Dept Civil Engn, Evanston, IL 60208 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Keer, LM (reprint author), Northwestern Univ, Dept Civil Engn, Evanston, IL 60208 USA. RI Keer, Leon/B-7017-2009 NR 9 TC 6 Z9 8 U1 0 U2 1 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0021-8936 J9 J APPL MECH-T ASME JI J. Appl. Mech.-Trans. ASME PD JUN PY 1998 VL 65 IS 2 BP 489 EP 496 DI 10.1115/1.2789081 PG 8 WC Mechanics SC Mechanics GA ZZ804 UT WOS:000074768800028 ER PT J AU de Wekker, SFJ Zhong, SY Fast, JD Whiteman, CD AF de Wekker, SFJ Zhong, SY Fast, JD Whiteman, CD TI A numerical study of the thermally driven plain-to-basin wind over idealized basin topographies SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID ENERGY BUDGET; VALLEY WINDS; HEAT-BUDGET; DEEP VALLEY; MOUNTAIN; ENVIRONMENT; SIMULATION; TRANSPORT; TERRAIN; FLOWS AB Numerical experiments have been carried out with a two-dimensional nonhydrostatic mesoscale model to investigate the diurnal temperature range in a basin and the thermally driven plain-to-basin winds. Under clear-sky conditions, the diurnal temperature range in a basin is larger than over the surrounding plains due to a combination of larger turbulent sensible heat fluxes over the sidewalls and a volume effect in which energy fluxes are distributed through the smaller basin atmosphere. Around sunset, a thermally driven plain-to-basin how develops, transporting air from the plains into the basin. Characteristic of this plain-to-basin wind are described for idealized basins bounded by sinusoidal mountains and the circumstances under which such winds might or might not occur are considered. In contrast with a previous numerical study, it is found that the height of the mixed layer over the plains relative to the mountain height is not a critical factor governing the occurrence or nonoccurrence of a plain-to-basin wind. The critical factor is the horizontal temperature gradient above mountain height created by a larger daytime heating rate over the basin topography than over the plains. Subsidence and turbulent heat flux divergence play important roles in this heating above mountain height. C1 Pacific NW Lab, Richland, WA 99352 USA. RP de Wekker, SFJ (reprint author), Univ British Columbia, Dept Geog, Atmospher Sci Programme, Vancouver, BC V6T 1Z2, Canada. OI De Wekker, Stephan/0000-0002-6343-854X NR 38 TC 35 Z9 35 U1 0 U2 4 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 JUN PY 1998 VL 37 IS 6 BP 606 EP 622 DI 10.1175/1520-0450(1998)037<0606:ANSOTT>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZV750 UT WOS:000074337400005 ER PT J AU Bardenhagen, SG Brackbill, JU AF Bardenhagen, SG Brackbill, JU TI Dynamic stress bridging in granular material SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID NUMERICAL-SIMULATION; UNIAXIAL COMPRESSION; FORCE FLUCTUATIONS; 2D PACKINGS; BEAD PACKS; MEDIA; CYLINDERS; MODEL; MECHANICS; SYSTEMS AB Through numerical experiments we investigate stress localization in granular material with application to plastic-bonded explosives. The results shed light on static versus dynamic loading, and on the role of an interstitial material between grains. Under static loading, we observe stress localization and bridging in a lattice of polydisperse cylinders in two dimensions. Under dynamic loading, we observe a two wave structure with stress fingers propagating ahead of a normal compaction wave. When an interstitial material is added (a polymeric binder), force fluctuations are substantially reduced under both static and dynamic loading. Under dynamic loading, the structure of the stress wave depends upon the material properties of the binder. As the binder stiffness increases, stress fingering decreases and is replaced by a planar compaction wave. (C) 1998 American Institute of Physics. [S0021-8979(98)10310-9]. C1 Los Alamos Natl Lab, Engn Sci & Applicat Div, Los Alamos, NM 87545 USA. Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Los Alamos Natl Lab, Engn Sci & Applicat Div, POB 1663, Los Alamos, NM 87545 USA. EM bard@lanl.gov NR 28 TC 53 Z9 55 U1 0 U2 6 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 JUN 1 PY 1998 VL 83 IS 11 BP 5732 EP 5740 DI 10.1063/1.367429 PN 1 PG 9 WC Physics, Applied SC Physics GA 108GE UT WOS:000075257100018 ER PT J AU Cook, BA Harringa, JL Vining, CB AF Cook, BA Harringa, JL Vining, CB TI Electrical properties of Ga and ZnS doped ZnO prepared by mechanical alloying SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB A series of n-type ZnO alloys doped with Ga and ZnS were prepared by mechanical alloying. Densities of 95% Co 98% of theoretical density were achieved by hot pressing the milled powders at 1000 and 1200 degrees C, respectively. The electrical resistivity and Seebeck coefficient of alloys containing 0.25-3.0 at, % Ga were characterized between 22 and 1000 degrees C, The magnitude of the resistivity and Seebeck coefficient at 22 degrees C ranged from 0.2 m Omega cm and -25 mu V/degrees C for the most heavily doped specimen to 1.1 m Omega cm and -70 mu V/degrees C for the lightly doped material. The alloys exhibit a positive temperature coefficient of resistivity and Seebeck coefficient with a nearly constant slope over the temperature range studied. Thermal diffusivity measurements on a specimen containing 1.0 at. % Ga were performed over the same temperature range. The thermal conductivity appears to follow a T-1 dependence, decreasing from 180 mW/cm degrees C at 22 degrees C to 82 mW/cm degrees C at 1000 degrees C, An estimate of the maximum dimensionless thermoelectric figure of merit, ZT, in this system at 1000 degrees C gives a value of 0.26, a factor of three to four less than current state-of-the-art materials such as Si-Ge, A significant reduction in thermal conductivity would be required to make these alloys competitive with existing thermoelectric power generation materials. (C) 1998 American Institute of Physics. [S0021-8979(98)03011-4]. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. ZT Serv Inc, Auburn, AL 36830 USA. RP Cook, BA (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 9 TC 33 Z9 33 U1 1 U2 19 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 5858 EP 5861 DI 10.1063/1.367445 PN 1 PG 4 WC Physics, Applied SC Physics GA 108GE UT WOS:000075257100037 ER PT J AU Varga, L Jiang, H Klemmer, TJ Doyle, WD Payzant, EA AF Varga, L Jiang, H Klemmer, TJ Doyle, WD Payzant, EA TI Magnetic and structural properties of epitaxially grown FeTaN thin films SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SURFACE-MORPHOLOGY; SI(111) SURFACES; SOFT MAGNETISM; FE; MAGNETOSTRICTION; MICROSTRUCTURE; MOMENT; HEADS; CU AB Epitaxial FeTaN films (similar to 1500 Angstrom) were grown as a function of nitrogen flow rate on epitaxial Cu(001) buffer layers (similar to 2000 Angstrom) on Si(001) single crystal substrates to investigate the effect of Ta and nitrogen on the magnetocrystalline anisotropy and magnetostriction. detailed structural investigation by transmission electron microscopy and x-ray diffraction showed that the FeTaN films were epitaxial with the Pitsch orientation relationship of FeTaN(110)parallel to Cu(001) and FeTaN[111]parallel to Cu[110], which allows four different in-plane variants to coexist in the film. It was found that the saturation magnetization did not change with nitrogen addition (similar to 1600 emu/cc) up to 2% lattice dilation. The values of K-1 and lambda(100) of Fe decreased slightly (20% and 10%, respectively), while lambda(111) increased with increasing nitrogen content and eventually changed sign at similar to 2% normalized lattice dilation. These results qualitatively agree with our earlier findings on (001) oriented FeTaN epitaxial films on MgO single crystal substrates. Also, our calculated saturation magnetostriction for nanocrystalline samples agrees very well with published data on the same FeTaN composition. Based on Hoffinann's ripple theory the ripple constant is calculated for nanocrystalline films using the Doyle-Finnegan model for the local average anisotropy and our measured single crystal constants. It was found that the effect of nitrogen on reducing the average anisotropy through the fundamental constants is not significant, and therefore the major factor in achieving a low ripple constant (i.e., soft magnetic properties) is the grain size, the number of grains across the thickness and the thin film stress. (C) 1998 American Institute of Physics. [S0021-8979(98)01811-8]. C1 Univ Alabama, Dept Phys & Astron, Ctr Mat Informat Technol, Tuscaloosa, AL 35487 USA. Oak Ridge Natl Lab, High Temp Mat Lab, Diffract & Thermophys Properties Grp, Oak Ridge, TN 37831 USA. RP Varga, L (reprint author), Univ Alabama, Dept Phys & Astron, Ctr Mat Informat Technol, POB 870202, Tuscaloosa, AL 35487 USA. RI Payzant, Edward/B-5449-2009 OI Payzant, Edward/0000-0002-3447-2060 NR 42 TC 24 Z9 26 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 5955 EP 5966 DI 10.1063/1.367460 PN 1 PG 12 WC Physics, Applied SC Physics GA 108GE UT WOS:000075257100053 ER PT J AU Gole, JL Dixon, DA AF Gole, JL Dixon, DA TI Evidence for oxide formation from the single and multiphoton excitation of a porous silicon surface or silicon "nanoparticles" SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID OPTICAL-PROPERTIES; LUMINESCENCE; SI; PHOTOLUMINESCENCE; IDENTIFICATION; ABSTRACTION; PREDICTION; OXIDATION; EXCITONS; SPECTRA AB Potential oxidation as monitored by single and multiphoton excitation and associated with the laser induced photoluminescence (PL) from silicon nanoparticles and a porous silicon (PS) surface is considered in the light of recent ir? situ observations of the photoluminescence process coupled with detailed quantum chemical modeling of the silanone based oxyhydrides. The enhanced oxidation of PS surface bound SiHx moieties as they undergo multiphoton excitation through the SiHx stretch vibrational ladder to the quasicontinuum is suggested as a source of the visible PL produced in the 600-800 nm region. Vibrational-to-electronic energy transfer within the SiHx manifold, as previously suggested, is thought to be unlikely. However, the formation of OSiHx constituencies on the PS surface as these are associated with the silanone-based silicon oxyhydrides would appear to be significant. Evidence for these oxyhydrides may also be apparent in the laser induced PL from silicon nanoparticles. All experimental observations are explained without envoking quantum confinement. (C) 1998 American Institute of Physics. [S0021-8979(98)08211-5]. C1 Georgia Inst Technol, Sch Phys, Atlanta, GA 30332 USA. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Georgia Inst Technol, Sch Phys, Atlanta, GA 30332 USA. NR 44 TC 7 Z9 7 U1 0 U2 3 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 JUN 1 PY 1998 VL 83 IS 11 BP 5985 EP 5991 DI 10.1063/1.367464 PN 1 PG 7 WC Physics, Applied SC Physics GA 108GE UT WOS:000075257100057 ER PT J AU Zhang, WM Huebner, W Sampayan, SE Krogh, ML AF Zhang, WM Huebner, W Sampayan, SE Krogh, ML TI Mixed electron emission from lead zirconate-titanate ceramics SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID FERROELECTRICS; CATHODES AB Simultaneous ferroelectric and plasma emission from Pb(Zr,Ti)O-3 was observed with only a negative driving pulse applied to the sample, and without an extraction potential on the electron collector. Plasma emission was a strong, inconsistent, and self-destructive process. In addition, a positive ion current was detected. Comparatively, ferroelectric emission was a relatively stable self-emission process, exhibiting no apparent delay time, and no positive ion current. The relationship between the switching and emission current of ferroelectric samples measured simultaneously cannot only be used to determine the existence of ferroelectric emission, but can also give direction to choosing suitable ferroelectric materials for emitter applications. (C) 1998 American Institute of Physics. [S0021-8979(98)03911-5]. C1 Univ Missouri, Dept Ceram Engn, Rolla, MO 65401 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Allied Signal Fed Mfg & Technol, Kansas City, MO 64141 USA. RP Zhang, WM (reprint author), Univ Missouri, Dept Ceram Engn, Rolla, MO 65401 USA. EM weiming@umr.edu NR 28 TC 33 Z9 33 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 6055 EP 6060 DI 10.1063/1.367474 PN 1 PG 6 WC Physics, Applied SC Physics GA 108GE UT WOS:000075257100069 ER PT J AU Meng, WJ Curtis, TJ Rehn, LE Baldo, PM AF Meng, WJ Curtis, TJ Rehn, LE Baldo, PM TI Plasma-assisted deposition and characterization of Ti-containing diamondlike carbon coatings SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ION-BEAM; FILMS AB We report on the synthesis of Ti-containing diamondlike hydrocarbon (Ti-DLC) coatings by plasma-assisted physical vapor deposition and the characterization of coating microstructure and mechanical properties. We find that Ti-DLC coatings with Ti compositions higher than 5.5 at. % an composites consisting of nanocrystalline TiC in an amorphous hydrocarbon matrix. The hardness and elastic modulus of Ti-DLC coatings are found to increase monotonically with increasing Ti composition, while the ratio of the hardness to the modulus remains approximately constant. (C) 1998 American Institute of Physics. [S0021-8979(98)07511-2]. C1 GM Corp, Ctr Res & Dev, Warren, MI 48090 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP Meng, WJ (reprint author), GM Corp, Ctr Res & Dev, Warren, MI 48090 USA. NR 16 TC 32 Z9 32 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 6076 EP 6081 DI 10.1063/1.367477 PN 1 PG 6 WC Physics, Applied SC Physics GA 108GE UT WOS:000075257100072 ER PT J AU Angadi, MA Gosztola, D Wasielewski, MR AF Angadi, MA Gosztola, D Wasielewski, MR TI Characterization of photovoltaic cells using poly(phenylenevinylene) doped with perylenediimide electron acceptors SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID DIODES; HETEROJUNCTIONS; PHOTODIODES; POLYMERS; DYE AB The performance of a sandwich junction device based on doped 1,4-bis(2-ethylhexyloxy)phenylenevinylene (BEH-PPV) is reported. The power conversion efficiency is dependent on the doping level, external load, and work function of the cathode. The increase in power conversion efficiency (eta(e)=0.8%) is due to efficient charge separation resulting from photoinduced electron transfer from the BEH-PPV donor to the perylene dicarboximide acceptor. (C) 1998 American Institute of Physics. [S0021-8979(98)01411-X] C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Northwestern Univ, Dept Chem, Evanston, IL 60208 USA. RP Angadi, MA (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Gosztola, David/D-9320-2011 OI Gosztola, David/0000-0003-2674-1379 NR 18 TC 46 Z9 46 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 6187 EP 6189 DI 10.1063/1.367491 PN 1 PG 3 WC Physics, Applied SC Physics GA 108GE UT WOS:000075257100088 ER PT J AU Jiang, JS Fullerton, EE Grimsditch, M Sowers, CH Bader, SD AF Jiang, JS Fullerton, EE Grimsditch, M Sowers, CH Bader, SD TI Exchange-spring behavior in epitaxial hard/soft magnetic bilayer films SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID PERMANENT MAGNETISM; 2-PHASE MAGNETS; FE AB We present results on the magnetic reversal process in epitaxial Sm-Co(1 (1) over bar 00)/TM (TM=Fe, Co) bilayer films prepared via magnetron sputtering onto Cr-buffered single-crystal MgO substrates. The magnetically hard Sm-Co films have 20 T uniaxial anisotropy and coercivities >3 T at room temperature. The magnetization of the soft layer is pinned at the interface to the hard-magnet layer and switches reversibly as expected for an exchange-spring magnet. With increasing soft layer thickness, the coercive field of the hard layer becomes significantly less than that of a single layer. We also present numerical solutions to a one-dimensional model that provide the spin configuration for each atomic layer. Comparison of the experimental results with the model simulations indicates that the exchange-spring behavior of our bilayer films can be understood from the intrinsic parameters of the hard and soft layers. (C) 1998 American Institute of Physics. [S0021-8979(98)42611-2]. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Jiang, JS (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Bader, Samuel/A-2995-2013; Fullerton, Eric/H-8445-2013 OI Fullerton, Eric/0000-0002-4725-9509 NR 16 TC 26 Z9 26 U1 1 U2 15 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 6238 EP 6240 DI 10.1063/1.367769 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500008 ER PT J AU Lewis, LH Wang, JY Welch, DO Panchanathan, V AF Lewis, LH Wang, JY Welch, DO Panchanathan, V TI Anomalous high-temperature coercivities in hard nanocomposite alloys SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID MAGNETIC-PROPERTIES; PHASE AB To elucidate the interphase interactions inherent to nanocomposite magnetic alloys, measurements of remanence B-r, and coercivity H-ci were made on a series of four meltspun, remanence-enhanced nanocomposite alloys consisting solely of various amounts of Nd2Fe14B and alpha-Fe. The phase constitution and microstructural scale of the alloys were characterized with synchrotron x-ray diffraction, Magnetic measurements were made using superconducting quantum interference device (SQUID) magnetometry on evacuated and encapsulated samples in the temperature range of 300 K less than or equal to T less than or equal to 750 K, in order to characterize the alpha-Fe component independently of the Nd2Fe14B component. The high-temperature coercivities of the samples increase with the amount of alpha-Fe present in the samples, ranging from an average value of approximately 75 Oe for the sample with 14 wt % excess Fe to over 400 Oe at 700 K for the sample with 27 wt % excess Fe, The relatively high coercivities of the samples found at elevated temperatures imply that a tabular morphology of the alpha-Fe grains is conferring anisotropy to the phase; this conclusion is supported by transmission electron microscopy. It is concluded that while the significant coercivity of the alpha-Fe phase likely reduces the room-temperature remanence enhancement of the alloy below its theoretical ideal, the favorable interphase interface orientation promotes exchange coupling. (C) 1998 American Institute of Physics. [S0021-8979(98)20811-5]. C1 Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. Magnequench Int Inc, Anderson, IN 46013 USA. RP Lewis, LH (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. NR 8 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 6274 EP 6276 DI 10.1063/1.367573 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500019 ER PT J AU Waldfried, C McIlroy, DN McAvoy, T Welipitiya, D Dowben, PA Vescovo, E AF Waldfried, C McIlroy, DN McAvoy, T Welipitiya, D Dowben, PA Vescovo, E TI Strain induced alteration of the gadolinium surface state SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID SPIN-POLARIZED PHOTOEMISSION; TEMPERATURE; AG(111) AB The electronic structure of strained and unstrained Gd(0001) has been studied with photoemission, inverse photoemission, and spin-polarized photoemission, A shift of the occupied majority and unoccupied minority surface states has been observed as a result of the strain, consistent with the phase accumulation model. There is a strain induced shift of the minority spin surface state across the Fermi level. (C) 1998 American Institute of Physics. [S0021-8979(98)28611-7]. C1 Univ Nebraska, Dept Phys & Astron, Lincoln, NE 68588 USA. Univ Nebraska, Ctr Mat Res & Anal, Lincoln, NE 68588 USA. Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. RP Waldfried, C (reprint author), Univ Nebraska, Dept Phys & Astron, Lincoln, NE 68588 USA. EM pdowben@unlinfo.unl.edu NR 14 TC 2 Z9 2 U1 3 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 6284 EP 6286 DI 10.1063/1.367647 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500022 ER PT J AU Freeland, JW Chakarian, V Bussmann, K Idzerda, YU Wende, H Kao, CC AF Freeland, JW Chakarian, V Bussmann, K Idzerda, YU Wende, H Kao, CC TI Exploring magnetic roughness in CoFe thin films SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID X-RAY; CIRCULAR-DICHROISM; SCATTERING; SUPERLATTICES; MULTILAYERS; EDGES AB The behavior of chemical and magnetic interfaces is explored using diffuse x-ray resonant magnetic scattering (XRMS) for CoFe thin films with varying interfacial roughnesses. A comparison of the chemical versus magnetic interfaces shows distinct differences in the behavior of these two related interfaces as the chemical roughness is increased. Such changes appear to be correlated with the behavior of the magnetic hysteresis of the interface, measured by tracking the diffuse XRMS intensity as a function of applied magnetic field. (C) 1998 American Institute of Physics. [S0021-8979(98)17511-4]. C1 USN, Res Lab, Washington, DC 20375 USA. Free Univ Berlin, D-14195 Berlin, Germany. Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. RP Freeland, JW (reprint author), Naval Res Lab, NSLS Bldg 725A-U4B, Upton, NY 11973 USA. RI Wende, Heiko/J-8505-2012 NR 19 TC 47 Z9 48 U1 0 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 6290 EP 6292 DI 10.1063/1.367544 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500024 ER PT J AU Tonnerre, JM Seve, L Barbara-Dechelette, A Bartolome, F Raoux, D Chakarian, V Kao, CC Fischer, H Andrieu, S Fruchart, O AF Tonnerre, JM Seve, L Barbara-Dechelette, A Bartolome, F Raoux, D Chakarian, V Kao, CC Fischer, H Andrieu, S Fruchart, O TI Soft x-ray resonant magnetic reflectivity study of thin films and multilayers SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID EXCHANGE SCATTERING; CIRCULAR-DICHROISM; IRON; EDGES; BCC AB Soft x-ray resonant magnetic reflectivity measurements on thin films and multilayers in a transverse geometry using linear polarized photons are presented. Magneto-optic calculations taking into account the layer roughness allows us to reproduce all the experimental features of the angular and energy reflectivity curves as well as the asymmetry ratio in both cases. Application to FexMn1-x alloy films epitaxially grown on Ir(001) brings more insights on the magnetic transition occurring at x=0.75. (C) 1998 American Institute of Physics. [S0021-8979(98)49911-0]. C1 Univ Grenoble 1, CNRS, Lab Cristallog, F-38042 Grenoble 9, France. USN, Res Lab, Washington, DC 20375 USA. Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. Univ Nancy, CNRS, LPM, F-54506 Vandoeuvre Nancy, France. Univ Grenoble 1, CNRS, Lab Louis Neel, F-38042 Grenoble 9, France. RP Tonnerre, JM (reprint author), Univ Grenoble 1, CNRS, Lab Cristallog, BP 166, F-38042 Grenoble 9, France. RI Bartolome, Fernando/K-1700-2014; andrieu, stephane/N-3654-2016; OI Bartolome, Fernando/0000-0002-0047-1772; andrieu, stephane/0000-0003-0373-8193; Fruchart, Olivier/0000-0001-7717-5229 NR 21 TC 26 Z9 26 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 6293 EP 6295 DI 10.1063/1.367837 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500025 ER PT J AU Argyriou, DN Kelley, TM Mitchell, JF Robinson, RA Osborn, R Rosenkranz, S Sheldon, RI Jorgensen, JD AF Argyriou, DN Kelley, TM Mitchell, JF Robinson, RA Osborn, R Rosenkranz, S Sheldon, RI Jorgensen, JD TI Two-dimensional ferromagnetic correlations above T-c in the naturally layered CMR manganite La2-2xSr1+2xMn2O7 (x = 0.3-0.4) SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID MAGNETORESISTANCE; LA1-XCAXMNO3; TRANSITION; EXCHANGE AB Neutron diffuse scattering in the form of rod-like features has been observed in single crystals of the layered CMR material La2-2xSr1-2xMn2O7 (x=0.4,0.36), consistent with the presence of 2D ferromagnetic spin correlations. These diffuse features are observed over a wide temperature region. However, their coherence length does not appear to diverge at T-C, although there is evidence of the development of three-dimensional correlations around ferromagnetic reflections of the 3D-ordered magnetic structure close to T-C. Quasi-elastic neutron scattering on a ceramic sample of x=0.3 shows that the lifetime of these ferromagnetic correlations increases at T-->T-C. They exhibit a spin-diffusion constant above T-C of similar to 5 meV Angstrom(2), much lower than that reported for La2/3Ca1/3MnO3. We discuss the relationship of these magnetic correlations to models of the ferromagnetic transition in CMR compounds. (C) 1998 American Institute of Physics. [S0021-8979(98)43211-0]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos Neutron Scattering Ctr, Los Alamos, NM 87545 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Argyriou, DN (reprint author), Univ Calif Los Alamos Natl Lab, Los Alamos Neutron Scattering Ctr, Los Alamos, NM 87545 USA. RI Osborn, Raymond/E-8676-2011; Rosenkranz, Stephan/E-4672-2011 OI Osborn, Raymond/0000-0001-9565-3140; Rosenkranz, Stephan/0000-0002-5659-0383 NR 16 TC 22 Z9 22 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 6374 EP 6378 DI 10.1063/1.367775 PN 2 PG 5 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500052 ER PT J AU Bader, SD Osgood, RM Miller, DJ Mitchell, JF Jiang, JS AF Bader, SD Osgood, RM Miller, DJ Mitchell, JF Jiang, JS TI Role of intergrowths in the properties of naturally layered manganite single crystals SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID GIANT MAGNETORESISTANCE; T-C; LA1.2SR1.8MN2O7; OXIDES; STATE AB Two-layered Ruddlesden-Popper phase SrO(La1-xSrxMnO3)(2), with x = 0.3 and 0.3, exhibits colossal magnetoresistance, a magnetic anisotropy which is strongly composition-dependent, very little remanence, and an anomalous low-field magnetization (M) plateau between the Curie temperature (T-C) and T* similar to 300 K. The resistivity peaks near T-C for both in-plane and out-of-plane currents. The magnetization plateau is not intrinsic to the crystal, but is attributed to intergrowth defects, consisting of one additional or missing SrO blocking layers, as observed in transmission electron micrographs. The intergrowths exhibit interesting two-dimensional magnetic behavior, for both the x = 0.3 and 0.3 compositions. For x = 0.4, M scales as (1 - T/T*)(beta), with beta = 0.25 +/-0.02, For x = 0.3, the intergrowths exhibit an easy axis in the a-b plane due to the shape anisotropy, while for T10 m/s for the TiC added alloy while >20 m/s was necessary without TiC. The overquenched samples contained a smaller fraction of alpha-Fe in smaller grains than the undercooled samples when Fe dendrites formed near the free surface during solidification. These Fe dendrites were not removed by annealing. In addition, large orientated 2-14-1 grains nucleated on the Fe dendrites. This combination is detrimental to the magnetic properties. The addition of TiC results in improved control of the microstructure over a larger fraction of the ribbon volume enhancing the magnetic properties. (C) 1998 American Institute of Physics. C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Lockheed Martin Idaho Technol Co, Idaho Falls, ID 83415 USA. Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. RP Kramer, MJ (reprint author), Iowa State Univ Sci & Technol, Ames Lab, 39 Wilhelm Hall, Ames, IA 50011 USA. NR 8 TC 9 Z9 11 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 6631 EP 6633 DI 10.1063/1.367929 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500136 ER PT J AU Boekema, C Ruiz, EJ Pobre, ZC Punjabi, SR Kong, F Vera, O Cooke, DW AF Boekema, C Ruiz, EJ Pobre, ZC Punjabi, SR Kong, F Vera, O Cooke, DW TI Plausible d-wave cuprate superconductivity: Muon-spin-relaxation studies of RBa2Cu3O7-delta vortex states SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID SR AB The rare-earth (R) magnetism and grain-size dependencies of magnetic field distributions in RBa2Cu3O7-delta (RBCO) vortex states have been studied. A maximum-entropy technique has been applied to transverse field muon-spin-relaxation data of several polycrystalline cuprate superconductors. The main vortex signals for R = Er, Gd, and Ho reveal signs of two peaks in the field distribution below the applied field (B-ext=1 kOe) as predicted for d-wave superconductivity. For the RBCO (R = Er, Gd, Ho, Eu, Y) vortex states, we have confirmed low-field tails in the field distributions well below B-ext. The low-field tail may be caused by magnetic frustration in the vortex state or possible CuO-chain superconductivity below 25 K. Any interpretation of these (magnetic) vortex anomalies should comprise unconventional non-Bardeen-Cooper-Schrieffer-like fundamental properties of the cuprate vortex states. (C) 1998 American Institute of Physics. C1 San Jose State Univ, Dept Phys, San Jose, CA 95192 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Boekema, C (reprint author), San Jose State Univ, Dept Phys, San Jose, CA 95192 USA. NR 12 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 6795 EP 6797 DI 10.1063/1.367907 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500191 ER PT J AU Yusuf, SM Fullerton, EE Osgood, RM Felcher, GP AF Yusuf, SM Fullerton, EE Osgood, RM Felcher, GP TI Depth-dependent magnetism of layered superconductors: Nb/Si SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID NB AB We have studied magnetic field penetration and vortex line formation in a [Nb(100 Angstrom)/Si(15 Angstrom)]x20 multilayer by magnetization and polarized neutron reflection. With the magnetic field applied parallel to the surface, the magnetization revealed the presence of a kink above H-cl indicative of transitions between one row of fluxoids and two rows of fluxoids parallel to the surface. The spin dependence of neutron reflectivity below H-cl was consistent with a penetration depth of 1200 Angstrom, substantially larger than that of bulk Nb. In the mixed phase (H-ext>H-et) the field was found to penetrate the surface, with a slope as found in the case of H-extH-cl vortices form inside the multilayer, in addition to there being surface penetration. A modulation of the vortex fields was found with the periodicity of the Nb/Si bilayers as evidenced by the spin dependence of the reflectivity at the first Bragg peak of the multilayer. (C) 1998 American Institute of Physics. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Yusuf, SM (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Fullerton, Eric/H-8445-2013 OI Fullerton, Eric/0000-0002-4725-9509 NR 6 TC 12 Z9 12 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 6801 EP 6803 DI 10.1063/1.367982 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500193 ER PT J AU Krishnan, KM Nelson, C Echer, CJ Farrow, RFC Marks, RF Kellock, AJ AF Krishnan, KM Nelson, C Echer, CJ Farrow, RFC Marks, RF Kellock, AJ TI Exchange biasing of permalloy films by MnxPt1-x: Role of composition and microstructure SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc AB The interfacial coupling energy, Delta sigma for polycrystalline Ni0.8Fe0.2 (100 Angstrom)/MnxPt1-x(t Angstrom)/SiO2 bilayers, has been determined from wedge samples spanning a MnxPt1-x composition range 0.42 100 K) and decreases monotonically with increasing field at high fields (0.5 T < H < 1T). Possible causes for these are also discussed. (C) 1998 American Institute of Physics.[S0021-8979(98)20411-7]. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Kwon, C (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Mail Stop K763, Los Alamos, NM 87545 USA. RI Kwon, Chuhee/A-8687-2008; Jia, Q. X./C-5194-2008 NR 18 TC 19 Z9 19 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 7052 EP 7054 DI 10.1063/1.367569 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500276 ER PT J AU Ju, HL Krishnan, KM Lederman, D AF Ju, HL Krishnan, KM Lederman, D TI Evolution of strain-dependent transport properties in ultrathin La0.67Sr0.33MnO3 films SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID EPITAXIAL-FILMS; MAGNETORESISTANCE; LA0.7CA0.3MNO3 AB We report on a systematic investigation of strain-induced lattice distortion effects on the crystal structure and transport properties of as-grown and postannealed ultrathin La0.67Sr0.33MnO3 epitaxial films grown on LaAlO3 (001) substrates by pulsed laser deposition. The resistivity of the as-grown films is critically dependent on the thickness, i.e., 100 Angstrom thick films show insulating behavior, 300 A thick films show metal-insulator transitions, and 500 Angstrom thick films show metallic behavior. However, all the annealed films show identical metallic behavior. Conventional theta-2 theta x-ray scans with momentum transfer (q) along the [001] direction, and theta-2 theta scans of the (103) and (113) peaks, with q having a component perpendicular to the growth direction, were used to measure the out-of-plane and in-plane lattice parameters of the sample. Phi scans of the (103) and (113) peaks revealed a fourfold symmetry which is consistent with a tetragonal unit cell. These data conclusively show that significantly elongated tetragonal structures (c/a = 1.02-1.04) are insulating whilst films with cubic unit cells, relaxed either due to annealing or as a function of thickness, have metallic characteristics. (C) 1998 American Institute of Physics. [S0021-8979(98)52911-8]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. W Virginia Univ, Dept Phys, Morgantown, WV 26506 USA. RP Krishnan, KM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. NR 10 TC 51 Z9 51 U1 0 U2 14 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 7073 EP 7075 DI 10.1063/1.367864 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500283 ER PT J AU Bartolome, F Tonnerre, JM Seve, L Raoux, D Lorenzo, JE Chaboy, J Garcia, LM Bartolome, J Krisch, M Rogalev, A Serimaa, R Kao, CC Cibin, G Marcelli, A AF Bartolome, F Tonnerre, JM Seve, L Raoux, D Lorenzo, JE Chaboy, J Garcia, LM Bartolome, J Krisch, M Rogalev, A Serimaa, R Kao, CC Cibin, G Marcelli, A TI Magnetic x-ray investigation at the L-2,L-3 edges of Nd in Nd2Fe14B SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID L(III) EDGE; DICHROISM; SCATTERING; SPECTRA AB A systematic study of x-ray magnetic circular dichroism, x-ray resonant magnetic scattering, and resonant inelastic x-ray scattering at the L-2,L-3 edges of Nd on Nd2Fe14B is presented. The combined information allows to assign a dipolar or quadrupolar origin to different features appearing in the experimental spectra and to study the thermal dependence of the Nd moment orientation below the spin reorientation transition which takes place at T-SRT=135 K, (C) 1998 American Institute of Physics. [S0021-8979(98)25011-0]. C1 CNRS, Cristallog Lab, F-38042 Grenoble 9, France. Univ Zaragoza, Fac Ciencias, CSIC, ICMA, E-50009 Zaragoza, Spain. European Synchrotron Radiat Facil, F-38043 Grenoble, France. Univ Helsinki, Dept Phys, FIN-00014 Helsinki, Finland. Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. RP Bartolome, F (reprint author), CNRS, Cristallog Lab, BP 166, F-38042 Grenoble 9, France. EM bartolom@polycnrs-gre.fr RI Bartolome, Fernando/K-1700-2014; Bartolome Sanjoaquin, Juan/G-2715-2014; Cibin, Giannantonio/G-2809-2015 OI Bartolome, Fernando/0000-0002-0047-1772; Bartolome Sanjoaquin, Juan/0000-0002-6517-1236; Cibin, Giannantonio/0000-0001-5761-6760 NR 12 TC 8 Z9 8 U1 1 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 7091 EP 7093 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500289 ER PT J AU Manoharan, SS Ju, HL Krishnan, KM AF Manoharan, SS Ju, HL Krishnan, KM TI Unusual substitutional properties of Ru in the La0.7Sr0.3Mn1-xRuxO3 system SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID GIANT MAGNETORESISTANCE; THIN-FILMS AB La0.7Sr0.3Mn1-xRuxO3, 0 less than or equal to x less than or equal to 0.2 samples were prepared both in bulk and thin film formed using pulsed laser deposition. Magnetization measurements of bulk samples indicate a marginal decrease in T-c from 366 to 335 K up to 15% Ru substitution in Mn site. X-ray diffraction of the < 100 > oriented epitaxial films indicate a monotonic increase in the lattice parameter with Ru doping. The magnetoresistive behavior of the Ru substituted films are comparable with the parent La0.7Sr0.3MnO3 films. Unlike other elemental substitution in Mn sites, the effect of Ru to stabilize magnetic ordering at elevated temperatures is exceptional. (C) 1998 American Institute of Physics. C1 Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Krishnan, KM (reprint author), Lawrence Berkeley Lab, Div Mat Sci, 72-150, Berkeley, CA 94720 USA. NR 9 TC 20 Z9 20 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 7183 EP 7185 DI 10.1063/1.367630 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500320 ER PT J AU Borchers, JA Ijiri, Y Lee, SH Majkrzak, CF Felcher, GP Takano, K Kodama, RH Berkowitz, AE AF Borchers, JA Ijiri, Y Lee, SH Majkrzak, CF Felcher, GP Takano, K Kodama, RH Berkowitz, AE TI Spin-flop tendencies in exchange-biased Co/CoO thin films SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID BILAYERS; SUPERLATTICES; ANISOTROPY; NIO AB In order to study the antiferromagnetic (AFM) spin structure near the interface of exchange-biased bilayers, polarized neutron diffraction measurements were performed on a series of (111)Co(7.5 nm)/CoO (X nm) and CoO (X nm) thin films where X = 20, 40, and 100 nm. In these samples, field cooling through the Neel temperature of the AFM increases the component of the CoO moment perpendicular to the applied field, relative to the parallel component. The subsequent application of a 500 Oe field perpendicular to the cooling direction rotates both the Co and CoO moments. Experiments on CoO films without Co showed a smaller difference between the parallel and perpendicular CoO moments in response to cooling and applied fields. Exchange coupling between the Co and CoO layers is apparently responsible for the increased projection of the AFM moments perpendicular to the cooling field. (C) 1998 American Institute of Physics. C1 NIST, Gaithersburg, MD 20899 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Calif San Diego, Ctr Magnet Recording Res, La Jolla, CA 94720 USA. RP Borchers, JA (reprint author), NIST, Gaithersburg, MD 20899 USA. EM borchers@rrdstrad.nist.gov NR 16 TC 20 Z9 20 U1 0 U2 9 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 7219 EP 7221 DI 10.1063/1.367939 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500332 ER PT J AU Schulthess, TC Butler, WH AF Schulthess, TC Butler, WH TI First-principles exchange interactions between ferromagnetic and antiferromagnetic films: Co on NiMn, a case study SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID SURFACE; BIAS AB Heisenberg exchange parameters at the interface of antiferromagnetic NiMn with ferromagnetic Co are calculated from first principles. We use a layer version of the Korringa-Kohn-Rostocker multiple-scattering approach and an expression, which is based on the expansion of the band energy, to calculate the exchange parameters from the underlying electronic structure. For bulk systems, the parameter sets yield Curie temperatures that are in good agreement with experimental values. In the interface region, the interlayer interactions in NiMn change significantly compared to the bulk while the intralayer interactions are almost unchanged. (C) 1998 American Institute of Physics. [S0021-8979(98)48511-6]. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Schulthess, TC (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. NR 12 TC 17 Z9 17 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 7225 EP 7227 DI 10.1063/1.367824 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500334 ER PT J AU Waldfried, C Welipitiya, D McAvoy, T Dowben, PA Vescovo, E AF Waldfried, C Welipitiya, D McAvoy, T Dowben, PA Vescovo, E TI Finite size scaling in the thin film limit SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID TRANSITION-METALS; CURIE-TEMPERATURE; GADOLINIUM AB The thickness dependent spin-polarized electronic structure of strained thin and ultrathin films of Gd is characterized by a distinct change in the critical exponent lambda in the formalism of finite size scaling. The reduced critical exponent in the ultrathin films can be correlated to the increased dominance of the surface magnetic structure and the increasing paramagnetic-like behavior of the bulk. (C) 1998 American Institute of Physics. [S0021-8979(98)34111-0]. C1 Univ Nebraska, Dept Phys & Astron, Lincoln, NE 68588 USA. Univ Nebraska, Ctr Mat Res & Anal, Lincoln, NE 68588 USA. Brookhaven Natl Lab, Natl Synchrotron Light Source Dept, Upton, NY 11973 USA. RP Waldfried, C (reprint author), Univ Nebraska, Dept Phys & Astron, Lincoln, NE 68588 USA. NR 21 TC 5 Z9 5 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 7246 EP 7248 DI 10.1063/1.367909 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500341 ER PT J AU Awana, VPS Dou, SX Felner, I Nowik, I Malik, SK Mehta, A Singh, R Narlikar, AV Yelon, WB AF Awana, VPS Dou, SX Felner, I Nowik, I Malik, SK Mehta, A Singh, R Narlikar, AV Yelon, WB TI Structural and magnetic properties of RSr2Fe3O9 (R = La, Y, Pr, and Gd) SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID NONSTOICHIOMETRIC PEROVSKITE SR2LAFE3O8+Y; MOSSBAUER-SPECTROSCOPY; OXYGEN VACANCIES AB We have investigated the RSr2Fe3O9 (R=La, Y, Pr, and Gd) materials by several experimental techniques, including x-ray and neutron diffraction, magnetic susceptibility, and Mossbauer spectroscopy measurements. All materials studied are single phase and crystallize in the hexagonal perovskite structure. Magnetic susceptibility studies reveal that, for R=La and Pr, the Fe ions order antiferromagnetically at about T-N =190 K. Short range magnetic correlations are observed up to 250 K. For R = La and Pr, Fe-57 Mossbauer studies reveal two inequivalent magnetic sextets below 190 K, with the area ratio 2:1. Above T-N, one singlet is observed with an isomer shift value typical to Fe4+ For R = Y and Gd, the magnetization curves do not lend themselves to easy determination of the magnetic transition due to an extra magnetic phase which exists up to 350 K. This phase is a result of deficiency of oxygen. The (57)Mossbauer spectra at 300 K indicate two superimposed singlet lines, and contain a small magnetic sextet. There is no indication that the R sublattice in RSr2Fe3O9 (R=Pr and Gd) orders magnetically down to 1.5 K. (C) 1998 American Institute of Physics. C1 Univ Wollongong, Ctr Superconduct & Elect Mat, Wollongong, NSW 2522, Australia. Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. Tata Inst Fundamental Res, Bombay 400005, Maharashtra, India. Stanford Synchrotron Radiat Lab, SLAC, Stanford, CA 94309 USA. Natl Phys Lab, New Delhi 110012, India. Univ Missouri, Res Reactor Facil, Columbia, MO 65211 USA. RP Awana, VPS (reprint author), Univ Wollongong, Ctr Superconduct & Elect Mat, Wollongong, NSW 2522, Australia. RI Gupta, Vishnu/B-9839-2009; Dou, Shi Xue/D-5179-2012; ayyadevara, rajaram/D-1572-2009; Awana, Veer/E-4938-2015 OI Dou, Shi Xue/0000-0003-3824-7693; NR 10 TC 9 Z9 9 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 7312 EP 7314 DI 10.1063/1.367834 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500363 ER PT J AU Rosenkranz, S Osborn, R Mitchell, JF Vasiliu-Doloc, L Lynn, JW Sinha, SK Argyriou, DN AF Rosenkranz, S Osborn, R Mitchell, JF Vasiliu-Doloc, L Lynn, JW Sinha, SK Argyriou, DN TI Magnetic correlations in the bilayer manganite La1.2Sr1.8Mn2O7 SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID GIANT MAGNETORESISTANCE; EXCHANGE AB Neutron scattering has been used to study the magnetic correlations in the double-layer manganite La1.2Sr1.8Mn2O7, which exhibits colossal magnetoresistance in the vicinity of the ferromagnetic transition at T-c = 112 K. Over a large temperature range above T-c, there is evidence for two-dimensional magnetic correlations which peak in intensity at the transition. Although the in-plane correlations are predominantly ferromagnetic, a strong canting of spins in neighboring planes within the bilayers, at an angle that is dependent on both the temperature and magnetic field, is observed. There are indications of a crossover to three-dimensional critical scattering very close to T-c, but the nature of the phase transition has yet to be determined. (C) 1998 American Institute of Physics. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. Univ Calif Los Alamos Natl Lab, Los Alamos Neutron Sci Ctr, Los Alamos, NM 87545 USA. Univ Maryland, College Pk, MD 20742 USA. RP Rosenkranz, S (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Osborn, Raymond/E-8676-2011; Rosenkranz, Stephan/E-4672-2011 OI Osborn, Raymond/0000-0001-9565-3140; Rosenkranz, Stephan/0000-0002-5659-0383 NR 15 TC 22 Z9 22 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 7348 EP 7350 DI 10.1063/1.367796 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500374 ER PT J AU Sharma, RP Fournier, P Greene, RL Venkatesan, T Mitchell, JF Miller, D AF Sharma, RP Fournier, P Greene, RL Venkatesan, T Mitchell, JF Miller, D TI The complex magnetic behavior and the role of dynamic structural fluctuations in La1.2Sr1.8Mn2O7 crystals SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID MAGNETORESISTANCE; ORDER AB The presence of dynamic structural distortions at the magnetic phase transitions in layered perovskite La1.2Sr1.8Mn2O7 crystals is found by ion channeling. Their amplitude is similar to 1.5 picometer between 70 and 150 K, twice as that expected due to the thermal vibrations and static changes seen by neutron diffraction. Over the range 150 to 320 K a total change of similar to 2.3 picometer is observed with discontinuities, which correlate well with the anomalous features seen in magnetic studies. In this material a small ferromagnetic component persists in the region 120 to 320 K, and it is fully paramagnetic above 320 K. (C) 1998 American Institute of Physics. C1 Univ Maryland, Dept Phys, Ctr Superconduct Res, College Pk, MD 20742 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Sharma, RP (reprint author), Univ Maryland, Dept Phys, Ctr Superconduct Res, College Pk, MD 20742 USA. RI Venkatesan, Thirumalai/E-1667-2013 NR 8 TC 4 Z9 4 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 7351 EP 7353 DI 10.1063/1.367797 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500375 ER PT J AU Kresin, VZ Wolf, SA AF Kresin, VZ Wolf, SA TI Isotope effect and T-c in manganites and high T-c oxides SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID RESISTIVITY; TRANSPORT; SYSTEM; SHIFT; FILMS AB Oxygen isotope effect in manganites (cuprates) is caused by the dynamic Jahn-Teller effect on the bridging oxygen ion (e.g., the ion between Mn3+ and Mn4+ in manganites). This effect leads also to the vibronic reduction and effective decrease of the ferromagnetic transition temperature. (C) 1998 American Institute of Physics. [S0021-8979(98)32211-2]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. USN, Res Lab, Washington, DC 20375 USA. RP Kresin, VZ (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RI Wolf, Stuart/A-7513-2009 NR 30 TC 7 Z9 7 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 7357 EP 7359 DI 10.1063/1.367679 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500377 ER PT J AU Golosov, DI Norman, MR Levin, K AF Golosov, DI Norman, MR Levin, K TI A mean field theory of magnets with competing double exchange and superexchange interactions SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID MAGNETORESISTANCE; LA1.2SR1.8MN2O7 AB We study the competition between ferromagnetic double exchange (DE) and direct nearest-neighbor antiferromagnetic exchange J(AF) in two-dimensional colossal magnetoresistance materials. Towards this end, a single site mean field theory is proposed which incorporates the hopping-mediated nature of the DE contribution. The canted state appears only under highly restricted conditions, Instead, in the regime where the antiferromagnetic and DE ferromagnetic interactions are of comparable scale land in the classical limit), the system exhibits ferro- or antiferromagnetic order with incomplete saturation of the lattice or sublattice magnetization, We interpret these results as an indication that spin fluctuations remain strong even at low temperatures and discuss the associated experimental implications, (C) 1998 American Institute of Physics, [S0021-8979(98)45611-1]. C1 Univ Chicago, James Franck Inst, Chicago, IL 60637 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Golosov, DI (reprint author), Univ Chicago, James Franck Inst, 5640 S Ellis Ave, Chicago, IL 60637 USA. RI Norman, Michael/C-3644-2013 NR 15 TC 7 Z9 7 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 7360 EP 7362 DI 10.1063/1.367798 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500378 ER PT J AU Coutant, CC AF Coutant, CC TI What is "normative" for fish pathogens? A perspective on the controversy over interactions between wild and cultured fish SO JOURNAL OF AQUATIC ANIMAL HEALTH LA English DT Article; Proceedings Paper CT Symposium on Pathogens and Diseases of Fish in Aquatic Ecosystems - Implications in Fisheries Management CY JUN 03-04, 1997 CL PORTLAND, OREGON SP Pacific NW Fish Hlth Protect Comm, Alaska Fish & Game, Amer Fisheries Soc, Colorado Wyoming Chapter, Amer Fisheries Soc, Fish Hlth Sect, BioProd, Clear Springs Foods Inc, Idaho Aquaculture Assoc, Montana Dept Fish Wildlife & Parks, Moore Clark, Muckelshoot Indian Tribe, Keta Creek Hatchery, Natl Marine Fisheries Serv, Nelson & Sons, Nisqually Indian Tribe, Clear Springs Hatchery, Oregon Dept Fish & Wildlife, Oregon State Univ, Suquamish Indian Tribe, Trout Unlimited, Univ Idaho, US Fish & Wildlife Serv, Washington Dept Fish & Wildlife, Western Chem, Western Fisheries Res Ctr, US Geol Survey, Western Reg Aquaculture Consortium, Whirling Dis Fdn ID USELESS PASTIME; SALMON; STOCKS AB In its report, Return to the River, the Independent Scientific Group (now called the Independent Scientific Advisory Board-the scientific peer review arm of the Northwest Power Planning Council) advanced the notion of a "normative river ecosystem" as a new conceptual foundation for salmonid recovery in the Columbia River basin. With this perspective, the sum of the best scientific understanding of how organisms and aquatic ecosystems naturally function should be the norm or standard of measure for how we judge the effects of human activities on aquatic systems. For the best likelihood of recovery, key aspects of altered systems should be brought back toward normative (although not necessarily fully back to the historical or pristine state); new alterations should be judged by how much they move key functions away from normative or what might be considered as normal. In this paper, I ask what "normative" is for fish pathogens and how this concept could help resolve the long-standing disputes between fish culturists and advocates of wild fish in fisheries management. Through literature review and parallels with the evolution of infectious diseases in human populations, I suggest that the concept can be useful for understanding and controlling pathogens and diseases of fish in aquatic ecosystems. One key to avoiding disease outbreaks appears to be maintenance of normal diversity in fish pathogens, intermediate hosts, and immunological types in fish. I encourage further exploration of the normative perspective as a guide to our research and evaluations of pathogens and diseases cf fish. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Coutant, CC (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. NR 21 TC 16 Z9 17 U1 0 U2 0 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 USA SN 0899-7659 J9 J AQUAT ANIM HEALTH JI J. Aquat. Anim. Health PD JUN PY 1998 VL 10 IS 2 BP 101 EP 106 DI 10.1577/1548-8667(1998)010<0101:WINFFP>2.0.CO;2 PG 6 WC Fisheries; Veterinary Sciences SC Fisheries; Veterinary Sciences GA ZU180 UT WOS:000074170300003 ER PT J AU Philipona, R Frohlich, C Dehne, K DeLuisi, J Augustine, J Dutton, E Nelson, D Forgan, B Novotny, P Hickey, J Love, SP Bender, S McArthur, B Ohmura, A Seymour, JH Foot, JS Shiobara, M Valero, FPJ Strawa, AW AF Philipona, R Frohlich, C Dehne, K DeLuisi, J Augustine, J Dutton, E Nelson, D Forgan, B Novotny, P Hickey, J Love, SP Bender, S McArthur, B Ohmura, A Seymour, JH Foot, JS Shiobara, M Valero, FPJ Strawa, AW TI The Baseline Surface Radiation Network pyrgeometer round-robin calibration experiment SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID PERFORMANCE; ACCURACY AB With the aim of improving the consistency of terrestrial and atmospheric longwave radiation measurements within the Baseline Surface Radiation Network, five: Eppley Precision Infrared Radiometer (PIR) pyrgeometers and one modified Mereorological Research Flight (MRF) pyrgeometer were individually calibrated by 11 specialist laboratories. The round-robin experiment was conducted in a "blind" sense in that the participants had no knowledge of the results of others until the wholl: series of calibrations had ended. The responsivities C(mu V/W m(-2)) determined by 6 of the 11 institutes were within about 2% of the median for all five PIR pyrgeometers. Among the six laboratories, the absolute deviation around the median of the deviations of the five instruments is less than 1%. This small scatter suggests that PII: pyrgeometers were stable at least during the two years of the experiment and that the six different calibration devices reproduce the responsivity C of PIR pyrgeometers consistently and within the precision required for climate applications. The results also suggest that the responsivity C can be determined without simultaneous determination of the dome correction factor k, if the temperature difference between pyrgeometer body and dome is negligible during calibration. For field measurements, however, k has to be precisely known. The calibration of the MRF pyrgeometer, although not performed by all institutes, also showed satisfactory results. C1 World Radiat Ctr, Phys Meteorolog Observ, CH-7260 Davos Dorf, Switzerland. Meteorolog Observat Potsdam, Potsdam, Germany. SRRB, Appl Res Lab, NOAA, Boulder, CO USA. CMDL, NOAA, Boulder, CO USA. Bur Meteorol, Melbourne, Vic, Australia. Eppley Lab, Newport, RI USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. Atmospher Environm Serv, Downsview, ON, Canada. ETH Zurich, Inst Geophys, CH-8093 Zurich, Switzerland. Meteorol Res Flight, Farnborough, Hants, England. Meteorol Res Inst, Tsukuba, Ibaraki 305, Japan. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Philipona, R (reprint author), World Radiat Ctr, Phys Meteorolog Observ, Dorfstr 33, CH-7260 Davos Dorf, Switzerland. NR 16 TC 34 Z9 34 U1 1 U2 3 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 JUN PY 1998 VL 15 IS 3 BP 687 EP 696 DI 10.1175/1520-0426(1998)015<0687:TBSRNP>2.0.CO;2 PG 10 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA ZQ890 UT WOS:000073913300007 ER PT J AU Huang, GX Myers, D AF Huang, GX Myers, D TI Subgoal strategies for solving board puzzles SO JOURNAL OF AUTOMATED REASONING LA English DT Article DE automated deduction; subgoal; puzzle AB We show that a few simple search strategies can solve a variety of difficult puzzles ranging from the 15-puzzle to central solitaire, Rubik's cube, and several of its variants. One of these strategies automatically generates subgoals; another finds efficient sets of rules for the subgoals. The subgoals are based on the reversal of simple logical implications. With these strategies and a simple learning algorithm, we not only solve particular instances of these problems but automatically generate programs that solve all instances of the problem with reasonable efficiency. Our automatically generated program for Rubik's cube can solve a fully scrambled cube in about two minutes on a 66 Mhz 486 PC. C1 Univ Hawaii, Dept Math, Honolulu, HI 96822 USA. Argonne Natl Lab, Argonne, IL 60439 USA. NR 17 TC 0 Z9 0 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0168-7433 J9 J AUTOM REASONING JI J. Autom. Reasoning PD JUN PY 1998 VL 20 IS 3 BP 215 EP 253 DI 10.1023/A:1005882724254 PG 39 WC Computer Science, Artificial Intelligence SC Computer Science GA ZE569 UT WOS:000072807100001 ER PT J AU Habara, H Yamamoto, S Ochsenfeld, C Head-Gordon, M Kaiser, RI Yuan, YT AF Habara, H Yamamoto, S Ochsenfeld, C Head-Gordon, M Kaiser, RI Yuan, YT TI Fourier transform millimeter-wave spectroscopy of the HCS radical in the (2)A ' ground electronic state SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MICROWAVE-SPECTRUM; CHEMISTRY; CLOUDS AB The 1(01)-0(00) rotational transition of the HCS radical in the (X) over tilde (2)A ' ground electronic state has been observed with a Fourier transform millimeter-wave spectrometer in combination with a pulsed discharge nozzle. The radical is produced by discharging a mixture of CH4 and H2S diluted in Ar. Six fine and hyperfine components are detected, and the effective rotational constant, spin-rotation interaction constant, and hyperfine interaction constants are determined accurately. The Fermi contact term of the hydrogen nucleus is found to be much smaller than that for the isovalent radical, HCO, indicating that the HCS radical is more close to a linear structure than the HCO radical. (C) 1998 American Institute of Physics, [S0021-9606(98)01521-9] C1 Univ Tokyo, Dept Phys, Bunkyo Ku, Tokyo 1130033, Japan. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Acad Sinica, Inst Atom & Mol Sci, Taipei 106, Taiwan. Tech Univ Chemnitz Zickau, Dept Phys, D-09107 Chemnitz, Germany. RP Habara, H (reprint author), Univ Tokyo, Dept Phys, Bunkyo Ku, Tokyo 1130033, Japan. RI Lee, Yuan-Tseh/F-7914-2012; Ochsenfeld, Christian/E-8021-2015 OI Ochsenfeld, Christian/0000-0002-4189-6558 NR 24 TC 23 Z9 23 U1 0 U2 6 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 1 PY 1998 VL 108 IS 21 BP 8859 EP 8863 DI 10.1063/1.476332 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 108FR UT WOS:000075255900011 ER PT J AU Sun, X Miller, WH AF Sun, X Miller, WH TI Semiclassical initial value representation for rotational degrees of freedom: The tunneling dynamics of HCl dimer SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MECHANICS; SPECTRA AB The semiclassical initial value representation (SC-IVR) isemerging as a practical way of generalizing classical trajectory simulation methods to include (approximately) the effects of quantum mechanics (i.e., interference and tunneling). This paper describes the application of the SC-IVR approach to determine the low lying vibrational states of the HCl dimer on a realistic potential energy surface. Overall agreement of the semiclassical energy levels with accurate quantum values is very good, including a good description of the tunneling splitting in the ground state. Issues regarding the applications of the SC-IVR methodology to the angular variables related to rotational degrees of freedom are explicitly discussed. (C) 1998 American Institute of Physics. [S0021-9606(98)01121-0] C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Sun, X (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Sun, Sean/C-6755-2009 OI Sun, Sean/0000-0002-9077-7088 NR 30 TC 84 Z9 84 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 1 PY 1998 VL 108 IS 21 BP 8870 EP 8877 DI 10.1063/1.476333 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 108FR UT WOS:000075255900013 ER PT J AU Mellinger, A Ashikhmin, MV Moore, CB AF Mellinger, A Ashikhmin, MV Moore, CB TI Experimental evidence for K-conservation in the dissociation of singlet ketene SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SPECTROSCOPY; ROTATION; STATE; PHOTODISSOCIATION AB The extent of K-mixing in the dissociation of ketene on its So potential energy surface has been investigated. Using a two-step photodissociation scheme for ketene and laser-induced fluorescence (LIF) to detect the CH2 radical, photofragment excitation (PHOFEX) spectra of high energy selectivity were recorded. The ratio of the step heights shows that K is strongly mixed for K > 0 and that for K = 0 the extent of mixing increases with J. (C) 1998 American Institute of Physics. [S0021-9606(98)01621-3] C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Mellinger, A (reprint author), Univ Potsdam, Inst Phys, Neuen Palais 10, D-14469 Potsdam, Germany. NR 22 TC 9 Z9 9 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 1 PY 1998 VL 108 IS 21 BP 8944 EP 8949 DI 10.1063/1.476339 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 108FR UT WOS:000075255900020 ER PT J AU Leung, K Csajka, FS AF Leung, K Csajka, FS TI Metal ammonia solutions: A lattice model approach SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID FALICOV-KIMBALL MODEL; LIQUID-AMMONIA; ELECTRON INTERACTIONS; INSULATOR-TRANSITION; DENSITY FLUCTUATIONS; PHASE-SEPARATION; MICROEMULSIONS; DIMENSIONS; LOCALIZATION; BIPOLARONS AB A generalized Falicov-Kimball model is applied to study the phase diagram of metal ammonia solutions. The model includes a fluid-fluid interaction term and an electron-fluid interaction with a hard core and an attractive tail. Mean-field theories are derived for the localized and delocalized electron phases using ideas from the slave-boson approach to the Hubbard model. The attractive force stabilizes both the homogeneous delocalized electron phase and a regime where the electrons localize in cavities devoid of fluid particles. In its absence, the localized states are found to be unstable towards phase separation, in contrast to previous predictions. The Gaussian fluctuations and structure factors derived from this theory suggest the-existence of bicontinuous channels percolating through the system. These findings agree qualitatively with experiments and computer simulations. (C) 1998 American Institute of Physics. [S0021-9606(98)50821-5]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Leung, K (reprint author), Sandia Natl Labs, MS 1421, Albuquerque, NM 87185 USA. EM kleung@sandia.gov NR 63 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 1 PY 1998 VL 108 IS 21 BP 9050 EP 9061 DI 10.1063/1.476351 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 108FR UT WOS:000075255900032 ER PT J AU Wilcoxon, JP Martin, JE Parsapour, F Wiedenman, B Kelley, DF AF Wilcoxon, JP Martin, JE Parsapour, F Wiedenman, B Kelley, DF TI Photoluminescence from nanosize gold clusters SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID COLLOIDAL SEMICONDUCTORS; OPTICAL-PROPERTIES; CDS PARTICLES; PHOTOCHEMISTRY AB We have observed visible light emission from nanosize gold clusters. Liquid chromatographic analysis of the metal clusters shows that relatively intense photoluminescence occurs only when the size of the metal nanocluster is sufficiently small (<5 nm). The emission is strongly Stokes shifted and is assigned to radiative recombination of Fermi level electrons and sp- or d-band holes. The electron and/or hole states are perturbed by surface states, as indicated by the dependence of the emission spectrum on the nature of the cluster surface. Finally, we found that large, nonemitting gold clusters can also be made luminescent by partial dissolution using KCN. (C) 1998 American Institute of Physics. [S0021-9606(98)00819-8]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Colorado State Univ, Dept Chem, Ft Collins, CO 80523 USA. RP Wilcoxon, JP (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 23 TC 403 Z9 411 U1 13 U2 126 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 1 PY 1998 VL 108 IS 21 BP 9137 EP 9143 DI 10.1063/1.476360 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 108FR UT WOS:000075255900041 ER PT J AU Barton, JW Hartz, SM Klasson, KT Davison, BH AF Barton, JW Hartz, SM Klasson, KT Davison, BH TI Microbial removal of alkanes from dilute gaseous waste streams: Mathematical modeling of advanced bioreactor systems SO JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY LA English DT Article DE VOC; biodegradation; alkanes; trickle-bed; mass transfer; kinetics ID BIOFILTRATION AB Many industries generate volatile organic compounds (VOCs) in dilute streams which must be removed before being released into the environment. Mathematical models for biological filters which can remediate waste streams are useful both as predictive tools and as a means to better understand the fundamental processes involved. Optimization of the system also necessitates a better understanding of the mechanisms by which biofilters work and can be approached through modeling and maximizing appropriate conditions for removal. In a trickle-bed bioreactor, VOCs (n-pentane and isobutane) were passed over a biofilm-coated packing which degraded the VOCs. Bacterial growth was controlled via liquid nutrient-limited media trickled through the reactor. Results from this trickle-bed system were analyzed by applying a simple mathematical model to accurately describe the processes which are believed to play important roles. The model was based on a two-step process: mass transfer in which the VOCs diffuse into the liquid biofilm, and kinetics by which VOCs are degraded by the biofilm. Modeling results revealed that both kinetic and mass transfer resistances were significant under typical operating conditions. (C) 1998 SCI. C1 Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. RP Davison, BH (reprint author), Oak Ridge Natl Lab, Div Chem Technol, POB 2008-6226, Oak Ridge, TN 37831 USA. RI Davison, Brian/D-7617-2013; OI Davison, Brian/0000-0002-7408-3609; Klasson, K. Thomas/0000-0003-3358-3081 NR 13 TC 11 Z9 11 U1 2 U2 4 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0268-2575 J9 J CHEM TECHNOL BIOT JI J. Chem. Technol. Biotechnol. PD JUN PY 1998 VL 72 IS 2 BP 93 EP 98 DI 10.1002/(SICI)1097-4660(199806)72:2<93::AID-JCTB889>3.0.CO;2-R PG 6 WC Biotechnology & Applied Microbiology; Chemistry, Multidisciplinary; Engineering, Environmental; Engineering, Chemical SC Biotechnology & Applied Microbiology; Chemistry; Engineering GA ZU607 UT WOS:000074215000001 ER PT J AU Holmes, HF Mesmer, RE AF Holmes, HF Mesmer, RE TI An isopiestic study of aqueous solutions of the alkali metal bromides at elevated temperatures SO JOURNAL OF CHEMICAL THERMODYNAMICS LA English DT Article DE MBr(aq); isopiestic; high-temperature; osmotic; activity ID RECIPROCAL SALT SYSTEMS; APPARENT MOLAR VOLUMES; THERMODYNAMIC PROPERTIES; ELECTROLYTE-SOLUTIONS; ACTIVITY-COEFFICIENTS; 38.0 MPA; NABR; WATER; DENSITIES; MGCL2 AB Isopiestic molalities of aqueous solutions of the alkali metal bromides have been measured at T = 383.15 K to T = 498.15 K. Aqueous NaCl served as the isopiestic standard for the calculation of osmotic coefficients. The ion-interaction model gave an excellent fit to the experimental osmotic coefficients and provided parameters for the calculation of activity coefficients. Osmotic and activity coefficients both decrease with increasing temperature in this temperature range. A simple model is presented from which activity and osmotic coefficients (at p(sat)) can be calculated as a function of molality for T = 273.15 K to T = 523.15 K. Comparison of the stoichiometric activity coefficients with those of the corresponding alkali metal chlorides reveals quite complicated relative behavior. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Holmes, HF (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, POB 2008, Oak Ridge, TN 37831 USA. EM rem@ornl.gov NR 46 TC 20 Z9 20 U1 1 U2 6 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 JUN PY 1998 VL 30 IS 6 BP 723 EP 741 DI 10.1006/jcht.1997.0377 PG 19 WC Thermodynamics; Chemistry, Physical SC Thermodynamics; Chemistry GA ZW883 UT WOS:000074457900007 ER PT J AU Brander, C Hartman, KE Trocha, AK Jones, NG Johnson, RP Korber, B Wentworth, P Buchbinder, SP Wolinsky, S Walker, BD Kalams, SA AF Brander, C Hartman, KE Trocha, AK Jones, NG Johnson, RP Korber, B Wentworth, P Buchbinder, SP Wolinsky, S Walker, BD Kalams, SA TI Lack of strong immune selection pressure by the immunodominant, HLA-A(*)0201-restricted cytotoxic T lymphocyte response in chronic human immunodeficiency virus-1 infection SO JOURNAL OF CLINICAL INVESTIGATION LA English DT Article DE AIDS; immunodominance; escape; variant; antigen processing ID EPSTEIN-BARR-VIRUS; DYNAMICS IN-VIVO; FINE SPECIFICITY; REVERSE-TRANSCRIPTASE; GENETIC-VARIATION; HIV-1 INFECTION; PEPTIDE BINDING; CELL EPITOPES; TYPE-1; RECOGNITION AB Despite detailed analysis of the HIV-l-specific cytotoxic T lymphocyte response by various groups, its relation to viral load and viral sequence variation remains controversial. We analyzed HLA-A*0201 restricted cytotoxic T lymphocyte responses in 17 HIV-l-infected individuals with viral loads ranging from < 400 to 221,000 HIV RNA molecules per milliliter of plasma. In 13 out of 17 infected subjects, CTL responses against the SLYNTVATL epitope (p17 Gag; aa 77-85) were detectable, whereas two other HLA-A*0201 restricted epitopes (ILKEPVHGV, IV9; and VIYQYMDDL, VL9) were only recognized by six and five individuals out of 17 individuals tested, respectively. Naturally occurring variants of the SL9 epitope were tested for binding to HLA-A*0201 and for recognition by specific T cell clones generated from five individuals. Although these variants were widely recognized, they differed by up to 10,000-fold in terms of variant peptide concentrations required for lysis of target cells. A comparison of viral sequences derived from 10 HLA-A*0201-positive individuals to sequences obtained from 11 HLA-A*0201-negative individuals demonstrated only weak evidence for immune selective pressure and thus question the in vivo efficacy of inmunodominant CTL responses present during chronic HIV-1 infection. C1 Massachusetts Gen Hosp, AIDS Res Ctr, Boston, MA 02114 USA. Massachusetts Gen Hosp, Infect Dis Unit, Boston, MA 02114 USA. Harvard Univ, Sch Med, Boston, MA 02114 USA. Harvard Univ, Sch Med, New England Reg Primate Ctr, Southborough, MA 01772 USA. Los Alamos Natl Labs, Div Theoret, Los Alamos, NM USA. Cytel Corp, San Diego, CA 92121 USA. Dept Publ Hlth, AIDS Off, San Francisco, CA 94102 USA. Northwestern Univ, Sch Med, Dept Med, Chicago, IL 60611 USA. RP Kalams, SA (reprint author), Massachusetts Gen Hosp East, Massachusetts Gen Hosp, AIDS Res Ctr, 149 13th St, Charlestown, MA 02129 USA. EM Kalams@helix.mgh.harvard.edu RI Wolinsky, Steven/B-2893-2012; OI Wolinsky, Steven/0000-0002-9625-6697; Korber, Bette/0000-0002-2026-5757 FU NIAID NIH HHS [R01 AI 33327, R01 AI30914, R37 AI28568] NR 67 TC 133 Z9 133 U1 0 U2 1 PU ROCKEFELLER UNIV PRESS PI NEW YORK PA 1114 FIRST AVE, 4TH FL, NEW YORK, NY 10021 USA SN 0021-9738 J9 J CLIN INVEST JI J. Clin. Invest. PD JUN 1 PY 1998 VL 101 IS 11 BP 2559 EP 2566 DI 10.1172/JCI2405 PG 8 WC Medicine, Research & Experimental SC Research & Experimental Medicine GA ZU136 UT WOS:000074165900028 PM 9616227 ER PT J AU Sun, YW Petersen, JN Clement, TP Hooker, BS AF Sun, YW Petersen, JN Clement, TP Hooker, BS TI Effect of reaction kinetics on predicted concentration profiles during subsurface bioremediation SO JOURNAL OF CONTAMINANT HYDROLOGY LA English DT Article DE contaminants; bioremediation processes; subsurface interaction ID POROUS-MEDIA; TRANSPORT; BIODEGRADATION; GROUNDWATER AB The lack of a complete mechanistic description of subsurface interactions between contaminants and microbes has limited the ability to predict the effectiveness of subsurface bioremediation processes. Important microbial processes which must be included in such mechanistic descriptions of bioremediation are microbial growth, death and transport, including microbial attachment to and detachment from the soil surfaces. Recent advances have provided a better understanding of the relationships between contaminant destruction rates and such microbial processes. In this manuscript, contaminant profiles predicted using more realistic descriptions are compared with those obtained using less complete, previously published mathematical models. The more comprehensive model described here includes mathematical descriptions for microbial growth and transport. Contaminant profiles predicted using this model are compared with those obtained when the contaminant destruction processes are described by assuming that (1) no reaction occurs, (2) the contaminant reacts instantaneously with any available oxygen, and (3) dual-substrate Monod kinetics without consideration of microbial growth and transport. This work demonstrates that if reaction kinetics are ignored, the size of the plume will be overpredicted at large times and if the reaction is assumed to occur instantaneously, the plume will be underpredicted at small times. Thus, if these processes are not included in the mathematical description of bioremediation, erroneous interpretations of site characterization data collected during this period would be likely. (C) 1998 Elsevier Science B.V. C1 Washington State Univ, Dept Chem Engn, Pullman, WA 99164 USA. Pacific NW Lab, Bioproc Grp, Richland, WA 99352 USA. RP Petersen, JN (reprint author), Washington State Univ, Dept Chem Engn, POB 642710, Pullman, WA 99164 USA. RI Petersen, James/B-8924-2008; Sun, Yunwei/C-9751-2010 NR 18 TC 10 Z9 10 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7722 J9 J CONTAM HYDROL JI J. Contam. Hydrol. PD JUN PY 1998 VL 31 IS 3-4 BP 359 EP 372 DI 10.1016/S0169-7722(97)00072-7 PG 14 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA ZW415 UT WOS:000074408700009 ER PT J AU Romano, LT McCluskey, MD Krusor, BS Bour, DP Chua, C Brennan, S Yu, KM AF Romano, LT McCluskey, MD Krusor, BS Bour, DP Chua, C Brennan, S Yu, KM TI Phase separation in annealed InGaN/GaN multiple quantum wells SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 2nd International Conference on Nitride Semiconductors (ICNS 97) CY OCT 27-31, 1997 CL TOKUSHIMA CITY, JAPAN SP Japan Soc Appl Phys, Inst Electr Informat & Commun Engineers, IEEE, Electron Devices Soc AB In-rich second phases were detected by transmission electron microscopy (TEM) in In0.27Ga0.73N multiple quantum well(MQW) samples that were annealed at 950 degrees C for 40 h. X-ray diffraction (XRD) measurements showed a shift in the zero-order diffraction peak toward GaN, consistent with the formation of an In-poor phase remaining in the InGaN wells. Voids were also found by TEM in the MQWs after annealing. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Xerox Corp, Palo Alto Res Ctr, Palo Alto, CA 94304 USA. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Stanford Synchrotron Radiat Lab, Menlo Park, CA 94720 USA. RP Romano, LT (reprint author), Xerox Corp, Palo Alto Res Ctr, 3333 Coyote Hill Rd, Palo Alto, CA 94304 USA. EM romano@parc.xerox.com RI Yu, Kin Man/J-1399-2012 OI Yu, Kin Man/0000-0003-1350-9642 NR 5 TC 15 Z9 15 U1 3 U2 13 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD JUN PY 1998 VL 189 BP 33 EP 36 DI 10.1016/S0022-0248(98)00151-1 PG 4 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA ZZ448 UT WOS:000074730400009 ER PT J AU Swartzentruber, BS AF Swartzentruber, BS TI Fundamentals of surface step and island formation mechanisms SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 6th International Conference on Chemical Beam Epitaxy and Related Growth Techniques CY SEP 07-10, 1997 CL MONTREUX, SWITZERLAND DE scanning tunneling microscopy; diffusion and migration; surface diffusion; silicon; surface defects; clusters ID SCANNING-TUNNELING-MICROSCOPY; VARIABLE-TEMPERATURE STM; SI AD-DIMERS; DIFFUSION-BARRIERS; SI(001) SURFACES; VICINAL SI(001); SI(100) SURFACE; SINGLE-LAYER; GROWTH; DYNAMICS AB The kinetics of adsorbed Si monomers and dimers, at submonolayer coverage, are measured using scanning tunneling microscopy (STM). Si monomers are observed in empty-state STM images acquired between room temperature and 115 degrees C. The monomers are trapped at the ends of rebonded-SB type dimer rows. When monomers thermally escape from the traps, they rapidly diffuse along the substrate dimer row until they find another unoccupied trap or return to their original trap. The binding activation barrier at isolated traps is similar to 1.0 eV. A slightly lower barrier exists for monomers to hop between the ends of neighbouring dimer rows - a process facilitating diffusion along segments of SE-type steps. In addition to monomers, the surface migration and the interactions of adsorbed Si dimers with steps and islands on Si(0 0 1) are quantified using atom-tracking STM. Diffusing dimers are reflected from steps, sides of islands, and certain surface defect structures. Site-specific free energies are extracted from measurements of lattice-site occupation probabilities of dimers trapped between these reflecting barriers. Relative to the free energy of isolated dimers on a terrace, dimers located at the first lattice site next to SA steps and the sides of islands are bound by similar to 0.03-0.06 eV. The binding decreases to half that at the second lattice site, and is indistinguishable from the free-terrace value at a distance of three or more lattice sites. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Swartzentruber, BS (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. EM bsswart@sandia.gov NR 36 TC 16 Z9 16 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD JUN PY 1998 VL 188 IS 1-4 BP 1 EP 10 DI 10.1016/S0022-0248(98)00039-6 PG 10 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA ZW211 UT WOS:000074386800002 ER PT J AU Sweet, AP Guthrie, JT Ng, MM AF Sweet, AP Guthrie, JT Ng, MM TI Teacher perceptions and student reading motivation SO JOURNAL OF EDUCATIONAL PSYCHOLOGY LA English DT Article ID JUNIOR-HIGH SCHOOL; CHILDRENS PERCEPTIONS; INTRINSIC MOTIVATION; PERCEIVED COMPETENCE; ACHIEVEMENT GOALS; CLASSROOM; BELIEFS; STRATEGIES; ENGAGEMENT; AUTONOMY AB Teacher perceptions of students' intrinsic motivation for reading were examined from the perspective of self-determination development and reading achievement. A sample of 68 teachers from randomly selected elementary schools that were representative of county characteristics rated 374 students on 6 aspects of motivation for reading, including individual, topical, activity-based, autonomy-supported, socially supported, and writing-related aspects. Quantitative and qualitative results showed that teachers perceived higher achievers to be relatively higher in intrinsic reading motivation (individual and topical) than in extrinsic reading motivation (activity-based and autonomy-supported). In contrast, teachers perceived lower achievers to be relatively more motivated by extrinsic contextual factors than by intrinsic factors. Teachers appear to possess implicit theories that are in accord with the self-determination perspective on the development of motivation and reading achievement. C1 US DOE, Off Educ Res & Improvement, Washington, DC 20208 USA. Univ Maryland, Dept Human Dev, College Pk, MD 20742 USA. St Bonaventure Univ, Dept Educ, St Bonaventure, NY USA. RP Sweet, AP (reprint author), US DOE, Off Educ Res & Improvement, 555 New Jersey Ave NW, Washington, DC 20208 USA. EM anne_sweet@ed.gov NR 66 TC 67 Z9 67 U1 2 U2 14 PU AMER PSYCHOLOGICAL ASSOC PI WASHINGTON PA 750 FIRST ST NE, WASHINGTON, DC 20002-4242 USA SN 0022-0663 J9 J EDUC PSYCHOL JI J. Educ. Psychol. PD JUN PY 1998 VL 90 IS 2 BP 210 EP 223 DI 10.1037/0022-0663.90.2.210 PG 14 WC Psychology, Educational SC Psychology GA ZV945 UT WOS:000074358100003 ER PT J AU Melendres, CA Bowmaker, GA Leger, JM Beden, B AF Melendres, CA Bowmaker, GA Leger, JM Beden, B TI In-situ synchrotron far infrared spectroscopy of surface films on a copper electrode in aqueous solutions SO JOURNAL OF ELECTROANALYTICAL CHEMISTRY LA English DT Article DE synchrotron source; infrared reflection-absorption spectra; spectroelectrochemical behavior of copper; synchrotron far IR spectroscopy ID INSITU RAMAN-SPECTROSCOPY; RADIATION; SPECTRA; SILVER; CUO AB Far infrared spectra of the surface films formed upon anodic oxidation of copper have been obtained in-situ for the first time in aqueous solution environments using a synchrotron source. The spectroelectrochemical behavior of copper was studied in NaOH and in a dilute solution of KSCN in perchlorate. The oxide film at - 0.05 V vs. SCE in 0.1 M NaOH solution has been identified as Cu2O. In the passive region at 0.3 V, CuO and Cu(OH), appear to be present on the surface. Vibrational bands observed in 0.025 M KSCN + perchlorate solution are attributed to a multilayer film of copper(I) thiocyanate. (C) 1998 Elsevier Science S.A. All rights reserved. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. Univ Auckland, Dept Chem, Auckland, New Zealand. Univ Poitiers, Chem Lab, CNRS, Poitiers, France. RP Melendres, CA (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI LEGER, Jean-Michel/D-1125-2013 OI LEGER, Jean-Michel/0000-0002-9879-5029 NR 20 TC 57 Z9 57 U1 0 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0022-0728 J9 J ELECTROANAL CHEM JI J. Electroanal. Chem. PD JUN 1 PY 1998 VL 449 IS 1-2 BP 215 EP 218 DI 10.1016/S0022-0728(97)00609-8 PG 4 WC Chemistry, Analytical; Electrochemistry SC Chemistry; Electrochemistry GA ZZ066 UT WOS:000074692300020 ER PT J AU Southworth, SH LeBrun, T Azuma, Y Dyall, KG AF Southworth, SH LeBrun, T Azuma, Y Dyall, KG TI Argon KM photoelectron satellites SO JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA LA English DT Article DE X-ray photoelectron spectroscopy; satellites; inner shell; shake theory ID SYNCHROTRON RADIATION; NONDIPOLAR ASYMMETRIES; SHELL PHOTOIONIZATION; ANGULAR-DISTRIBUTIONS; HIGH-RESOLUTION; CROSS-SECTION; AR K; THRESHOLD; SPECTRA; EDGE AB Satellite structure in the Ar K-shell photoelectron spectrum due to M-shell excitations was recorded at X-ray energies 122-422 eV above threshold. Relativistic, multiconfiguration shake-theory calculations give a good overall match to the main satellite features, showing that electron correlation in this case is qualitatively well described by the relaxation model. Conjugate satellite intensities appear to be negligible at the X-ray energies used in the experiment. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Natl Lab High Energy Phys, Photon Factory, Tsukuba, Ibaraki 305, Japan. NASA, Ames Res Ctr, Thermosci Inst, Moffett Field, CA 94035 USA. RP Southworth, SH (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 37 TC 4 Z9 4 U1 0 U2 6 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 JUN PY 1998 VL 94 IS 1-2 BP 33 EP 38 DI 10.1016/S0368-2048(98)00149-2 PG 6 WC Spectroscopy SC Spectroscopy GA 100GB UT WOS:000074806800005 ER PT J AU Olson, CG Chase, SJ Canfield, PC Lynch, DW AF Olson, CG Chase, SJ Canfield, PC Lynch, DW TI Crystal momentum conservation in resonant photoelectron emission SO JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA LA English DT Article; Proceedings Paper CT 4th International Workshop on Auger Spectroscopy and Electronic Structure CY JUN, 1997 CL JULICH, GERMANY DE crystal momentum conservation; angle-resolved photoemission; resonant enhancement ID PHOTOEMISSION; SPECTRA AB Angle-resolved photoemission spectra taken at the rare earth 4d resonance show crystal momentum conservation in emission from 5d states in LaSb and 4f derived states in Ce2Sb. In both cases the emission resulting from resonant enhancement is shown to be direct photoemission. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames, IA 50011 USA. RP Olson, CG (reprint author), Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. RI Canfield, Paul/H-2698-2014 NR 14 TC 11 Z9 11 U1 0 U2 2 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 JUN PY 1998 VL 93 IS 1-3 BP 175 EP 180 DI 10.1016/S0368-2048(98)00171-6 PG 6 WC Spectroscopy SC Spectroscopy GA ZY129 UT WOS:000074589200020 ER PT J AU Gotter, R Bartynski, RA Hulbert, SL Wu, XL Nozoye, H Zitnik, M AF Gotter, R Bartynski, RA Hulbert, SL Wu, XL Nozoye, H Zitnik, M TI Core-hole decay mechanism in Ru studied by Auger-photoelectron coincidence spectroscopy SO JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA LA English DT Article; Proceedings Paper CT 4th International Workshop on Auger Spectroscopy and Electronic Structure CY JUN, 1997 CL JULICH, GERMANY DE Ru; Auger-Photoelectron Coincidence Spectroscopy; core-hole decay mechanism ID SYNCHROTRON RADIATION; TRANSITIONS; SURFACE; SPECTRA; METALS AB In order to explore the photoexcitation and decay mechanism of holes created in the 4p core level in Ru, the N2,3VV Auger spectrum of the Ru(0001) surface has been measured in coincidence with several features of the photoemission spectra and vice versa. The main features of the core level photoemission spectrum and the Anger spectra can be successfully modelled by atomic-like multiplets of the p(5)d(8) and d(6) configurations respectively, meaning that the core hole is suddenly screened. Furthermore, the photoemission spectrum cannot be simply described by a 4p(1/2),4P(3/2) spin-orbit doublet, but the angular momentum coupling between the 4p core hole and the 4d open shell must be considered, The Auger electrons emitted in coincidence with the satellite feature, shifted 10 eV below the 4p core level, have a high energy threshold that exceeds the threshold of conventional Auger measurements by an amount corresponding to the downward energy shift of the satellite feature. This indicates that the excitation associated with the satellite feature is long-lived and participates in the Auger decay, Remaining differences between the experimental and the model spectra for the,Auger emission could be explained by correlation effects. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Ist Nazl Fis Mat, Lab Nazl TASC, I-34012 Trieste, Italy. Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08855 USA. Rutgers State Univ, Surface Modificat Lab, Piscataway, NJ 08855 USA. Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. Natl Inst Mat & Chem Res, Tsukuba, Ibaraki, Japan. Univ Ljubljana, Jozef Stefan Inst, Ljubljana 1000, Slovenia. RP Gotter, R (reprint author), Ist Nazl Fis Mat, Lab Nazl TASC, Padriciano 99, I-34012 Trieste, Italy. NR 25 TC 3 Z9 3 U1 1 U2 1 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 JUN PY 1998 VL 93 IS 1-3 BP 201 EP 207 DI 10.1016/S0368-2048(98)00175-3 PG 7 WC Spectroscopy SC Spectroscopy GA ZY129 UT WOS:000074589200024 ER PT J AU James, RB Brunett, B Heffelfinger, J Van Scyoc, J Lund, J Doty, FP Lingren, CL Olsen, R Cross, E Hermon, H Yoon, H Hilton, N Schieber, M Lee, EY Toney, J Schlesinger, TE Goorsky, M Yao, W Chen, H Burger, A AF James, RB Brunett, B Heffelfinger, J Van Scyoc, J Lund, J Doty, FP Lingren, CL Olsen, R Cross, E Hermon, H Yoon, H Hilton, N Schieber, M Lee, EY Toney, J Schlesinger, TE Goorsky, M Yao, W Chen, H Burger, A TI Material properties of large-volume cadmium zinc telluride crystals and their relationship to nuclear detector performance SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT US Workshop on the Physics and Chemistry of II - VI Materials CY OCT 21-23, 1997 CL SANTA BARBARA, CALIFORNIA SP USA, CECOM, NVESD, USA, SSDC, USN, Off Naval Res, USAF, Air Force Wright Lab, Amer Phys Soc, Minerals, Metals & Mat Soc DE CZT; etching; gamma-ray response; internal electric fields; nuclear detectors; microstructural properties; photoluminescence; precipitates ID GAMMA-RAY DETECTORS; HIGH-PRESSURE BRIDGMAN; CD1-XZNXTE; SPECTROMETERS; CDTE; ETCHANTS AB The material showing the greatest promise today for production of large-volume gamma-ray spectrometers operable at room temperature is cadmium zinc telluride (CZT). Unfortunately, because of deficiencies in the quality of the present material, high-resolution CZT spectrometers have thus far been limited to relatively small dimensions, which makes them inefficient at detecting high photon energies and ineffective for weak radiation signals except in near proximity. To exploit CZT fully, it will be necessary to make substantial improvements in the material quality. Improving the material involves advances in the crystallinity, purity, carrier lifetimes, and control of the electrical compensation mechanism. A more detailed understanding of the underlying material problems limiting the performance of CZT gamma-ray detectors is required; otherwise, problems with supply, delivery times, and unit cost of large-volume (>5 cm(3) active volume) CZT spectrometers are expected to continue. A variety of analytical and numerical techniques have been employed to quantify crystallinity, strain, impurities, compositional and stoichiometric variations, bulk and surface defect states, carrier mobilities and lifetimes, electric field distributions, and surface passivation. Data from these measurements were correlated with spatial maps of the gamma-ray and alpha particle spectroscopic response, add feedback on the effectiveness of crystal growth and detector fabrication procedures has been generated. The results of several of these analytical techniques will be presented in this paper. C1 Sandia Natl Labs, Livermore, CA 94550 USA. Univ Calif Los Angeles, Los Angeles, CA 90095 USA. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Digirad, San Diego, CA 92121 USA. Univ Arizona, Tucson, AZ 85724 USA. Univ Nebraska, Lincoln, NE 68588 USA. Fisk Univ, Nashville, TN 37208 USA. RP Chen, H (reprint author), Sandia Natl Labs, Livermore, CA 94550 USA. EM Rbjames@Sandia.Gov NR 46 TC 56 Z9 59 U1 1 U2 16 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 USA SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD JUN PY 1998 VL 27 IS 6 BP 788 EP 799 DI 10.1007/s11664-998-0055-x PG 12 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA ZV637 UT WOS:000074325800055 ER PT J AU Biefeld, RM Allerman, AA Baucom, KC AF Biefeld, RM Allerman, AA Baucom, KC TI The growth of AlInSb by metalorganic chemical vapor deposition SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Letter DE AlInSb; metalorganic chemical vapor deposition (MOCVD); tritertiarybutylaluminum (TTBAl); semiconductor heterostructures ID EPITAXIAL-GROWTH; PHASE EPITAXY AB We have grown AlxIn1-xSb epitaxial layers by metalorganic chemical vapor deposition using tritertiarybutylaluminum (TTBAl), trimethylindium (TMIn), and triethylantimony (TESb) as sources in a high speed rotating disk reactor. Growth temperatures of 435 to 505 degrees C at 200 Torr were investigated. The V/III ratio was varied from 1.6 to 7.2 and TTBAl/(TTBAl+TMIn) ratios of 0.26 to 0.82 were investigated. AlxIn1-xSb compositions from x = 0.002 to 0.52 were grown with TTBAl/(TTBAl+TMIn) ratios of 0.62 to 0.82. Under these conditions, no Al was incorporated for TTBA1/(TTBAl+TMIn) ratios less than 0.62. Hall measurements of AlxIn1-xSb showed hole concentrations between 5 x 10(16) cm(3) to 2 x 10(17) cm(-3) and mobilities of 24 to 91 cm(2)/Vs for not intentionally doped AlxIn1-xSb. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Biefeld, RM (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 14 TC 6 Z9 7 U1 0 U2 3 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 USA SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD JUN PY 1998 VL 27 IS 6 BP L43 EP L46 DI 10.1007/s11664-998-0060-0 PG 4 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA ZV637 UT WOS:000074325800060 ER PT J AU Aceves, SM Smith, JR AF Aceves, SM Smith, JR TI A desiccant dehumidifier for electric vehicle heating SO JOURNAL OF ENERGY RESOURCES TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT International Mechanical Engineering Congress and Exposition - Winter Annual Meeting of the ASME CY NOV 17-22, 1996 CL ATLANTA, GEORGIA SP Amer Soc Mech Engineers AB Vehicle heating requires a substantial amount of energy. Electric vehicles (EVs) generate little waste heat, and using battery energy for heating may consume a substantial fraction of the energy storage capacity, reducing the vehicle range, which is one of the most important parameters in determining EV acceptability. This paper analyzes the applicability of a desiccant dehumidifier for providing comfort heating in an EV with reduced energy consumption. A dehumidifier can reduce the heating load in a vehicle because it adsorbs the water vapor generated by the passengers, thereby avoiding water condensation on the windows without requiring a high external air ventilation rate or a high window temperature. The results indicate that the desiccant dehumidifier can reduce the steady-state heating loan by 60 percent or more under typical conditions. The reduction in heating load is such that waste heat may be enough to provide the required heating under most ambient conditions. Desiccant system dimensions and weight appear reasonable Sor packaging inside an EV. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Aceves, SM (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-641,7000 East Ave, Livermore, CA 94551 USA. EM saceves@llnl.gov; jrsmith@llnl.gov RI aceves, salvador/G-9052-2011 OI aceves, salvador/0000-0001-5687-7256 NR 25 TC 1 Z9 1 U1 0 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0195-0738 J9 J ENERG RESOUR-ASME JI J. Energy Resour. Technol.-Trans. ASME PD JUN PY 1998 VL 120 IS 2 BP 131 EP 136 DI 10.1115/1.2795023 PG 6 WC Energy & Fuels SC Energy & Fuels GA ZW720 UT WOS:000074441000007 ER PT J AU Aceves, SM Berry, GD AF Aceves, SM Berry, GD TI Thermodynamics of insulated pressure vessels for vehicular hydrogen storage SO JOURNAL OF ENERGY RESOURCES TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT International Mechanical Engineering Congress and Exposition, at the Winter Annual Meeting of the American-Society-of-Mechanical-Engineers CY NOV 16-21, 1997 CL DALLAS, TEXAS SP Amer Soc Mech Engineers AB This paper studies the application of insulated pressure vessels for hydrogen-fueled light-duty vehicles. insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LH2); low-temperature (46 K) compressed hydrogen (CH2); or ambient-temperature CH2. In this analysis, hydrogen temperatures, pressures, and venting losses are calculated for insulated pressure vessels fueled with LH2 or with low-temperature CH2, and the results are compared to those obtained in low-pressure LH2 ranks. Hydrogen losses are calculated as a function of daily driving distance during normal operation; as a function of time during long periods of vehicle inactivity; and as a function of initial vessel temperature during fueling. The results show that insulated pressure vessels have packaging characteristics comparable or better than those of conventional, low-pressure LH2 tanks, with greatly improved dormancy and much lower boil-off, and therefore appear to be a good alternative for vehicular hydrogen storage. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Aceves, SM (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-641,7000 East Ave, Livermore, CA 94551 USA. RI aceves, salvador/G-9052-2011 OI aceves, salvador/0000-0001-5687-7256 NR 17 TC 26 Z9 26 U1 0 U2 4 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0195-0738 J9 J ENERG RESOUR-ASME JI J. Energy Resour. Technol.-Trans. ASME PD JUN PY 1998 VL 120 IS 2 BP 137 EP 142 DI 10.1115/1.2795024 PG 6 WC Energy & Fuels SC Energy & Fuels GA ZW720 UT WOS:000074441000008 ER PT J AU Sullivan, TM Heiser, J Gard, A Senum, G AF Sullivan, TM Heiser, J Gard, A Senum, G TI Monitoring subsurface barrier integrity using perfluorocarbon tracers SO JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE LA English DT Article AB Subsurface barriers are an extremely promising remediation option to many waste-management problems. It is recognized that monitoring of the barrier is necessary to provide confidence in the ability of the barrier to contain the pollutants. However, the large size and deep placement of subsurface barriers make detection of leaks a challenging task. Therefore, typical geophysical methods are not suitable for the monitoring of an emplaced barrier's integrity. Perfluorocarbon tracers (PFTs) have been tested as a means of barrier verification at the Hanford geotechnical test facility, where a soil/cement barrier was emplaced around a buried drum. PFTs were injected beneath the drum for three days in the center of the barrier 3 m below grade. The concentration of PFTs in seven external and two internal monitoring wells has been measured as a function of time over a 17-day period. The data have been analyzed through numerical modeling to determine barrier integrity and PFT diffusion rates through the barrier. This paper discusses the experimental design, test results, data analysis, and modeling of PFT transport in the subsurface system. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. RP Sullivan, TM (reprint author), Brookhaven Natl Lab, Bldg 830, Upton, NY 11973 USA. NR 15 TC 10 Z9 12 U1 0 U2 2 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 USA SN 0733-9372 J9 J ENVIRON ENG-ASCE JI J. Environ. Eng.-ASCE PD JUN PY 1998 VL 124 IS 6 BP 490 EP 497 DI 10.1061/(ASCE)0733-9372(1998)124:6(490) PG 8 WC Engineering, Environmental; Engineering, Civil; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA ZP958 UT WOS:000073805900004 ER PT J AU Moline, GR Schreiber, ME Bahr, JM AF Moline, GR Schreiber, ME Bahr, JM TI Representative ground water monitoring in fractured porous systems SO JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE LA English DT Article AB Ground water flow and transport processes in fractured porous rocks present special challenges for obtaining representative samples. Designing appropriate monitoring programs for these systems requires an assessment of spatial and temporal variability (1) to define representativeness, and (2) to determine the most efficient and cost-effective methods for obtaining representative samples. Gas tracer studies, borehole tests, and geochemical sampling conducted at a fractured rock site in east Tennessee indicate large spatial and temporal variations in transport processes. Ground water flow as indicated by helium tracers moves predominantly along strike, perpendicular to hydraulic gradients except during storm events, demonstrating temporal variability in transport directions. Distinct vertical changes in water chemistry encountered in multilevel wells are indicative of discrete transport pathways in a poorly mixed system. Comparison of samples obtained from standard screened wells and multilevel wells show that screened wells mask these vertical variations in ground water composition and miss important transport pathways. Experimental results demonstrate the need for adequate characterization of spatial and temporal variations for appropriate placement and construction of monitoring wells, timing of ground water monitoring, and evaluation of exposure risk and contaminant flux in support of remedial decision making. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Univ Wisconsin, Dept Geol & Geophys, Madison, WI 53706 USA. RP Moline, GR (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. RI Schreiber, Madeline/A-5356-2009 OI Schreiber, Madeline/0000-0002-1858-7730 NR 15 TC 10 Z9 10 U1 1 U2 4 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 USA SN 0733-9372 J9 J ENVIRON ENG-ASCE JI J. Environ. Eng.-ASCE PD JUN PY 1998 VL 124 IS 6 BP 530 EP 538 DI 10.1061/(ASCE)0733-9372(1998)124:6(530) PG 9 WC Engineering, Environmental; Engineering, Civil; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA ZP958 UT WOS:000073805900010 ER PT J AU Herrmannsfeldt, WB AF Herrmannsfeldt, WB TI Relevance of plasma science to particle accelerators SO JOURNAL OF FUSION ENERGY LA English DT Article DE plasma; accelerators; fusion AB In following the theme of this Symposium, "Plasma Science and Its Applications," we may be suggesting to some readers that the "other" applications of Plasma Science somehow justify the existence of a field traditionally devoted to fusion energy. In fact, we do not believe that plasma science can or should be justified for its spin-off contributions. Nevertheless, the unity of science would be seriously threatened by a precipitous decline in the support for plasma science. It is that unity which repeatedly has been verified as one looks for how advances in one field are crucial to several other seemingly fundamentally different fields. Thus it is in this case, as a representative of the community of Particle Accelerator Scientists, that we show four significant areas in which the methods and the results of plasma science have been applied to Accelerator Science. We have deliberately skipped plasma ion sources which are perhaps the most obvious application of plasmas to accelerators. Two of our four examples are cases in which the computational methods of plasma science have been adopted, and two are examples in which the plasmas themselves are employed. One of each category are now actively in use and the other one in each category is being used to develop or design new devices. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Herrmannsfeldt, WB (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0164-0313 J9 J FUSION ENERG JI J. Fusion Energy PD JUN PY 1998 VL 17 IS 2 BP 99 EP 101 DI 10.1023/A:1021809202222 PG 3 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 341RE UT WOS:000088602700006 ER PT J AU Rasmussen, D Schoenberg, K Siemon, R Zweben, SJ AF Rasmussen, D Schoenberg, K Siemon, R Zweben, SJ TI Near term applications of plasma science and fusion research: National laboratory perspectives SO JOURNAL OF FUSION ENERGY LA English DT Article DE plasma applications; fusion applications AB This paper describes some of the near-term practical applications of plasma science from the perspective of National Laboratories involved with fusion research for many years. The first half of the paper presents suggestions for maintaining a healthy national program in this area. The second part of the paper gives specific examples of near-term plasma applications research at our laboratories. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. Princeton Plasma Phys Lab, Princeton, NJ 08540 USA. RP Rasmussen, D (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 2 TC 0 Z9 0 U1 0 U2 1 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0164-0313 J9 J FUSION ENERG JI J. Fusion Energy PD JUN PY 1998 VL 17 IS 2 BP 103 EP 115 DI 10.1023/A:1021861219060 PG 13 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 341RE UT WOS:000088602700007 ER PT J AU Markevich, D AF Markevich, D TI Education outreach SO JOURNAL OF FUSION ENERGY LA English DT Article DE fusion; education AB A survey is presented on the Education Outreach activities that are sponsored by the Department of Energy's Office of Fusion Energy Sciences, with emphasis on the scope of these activities and the history behind the effort. C1 US DOE, Off Fus Energy Sci, Germantown, MD 20874 USA. RP Markevich, D (reprint author), US DOE, Off Fus Energy Sci, SC-55,19901 Germantown Rd, Germantown, MD 20874 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0164-0313 J9 J FUSION ENERG JI J. Fusion Energy PD JUN PY 1998 VL 17 IS 2 BP 117 EP 119 DI 10.1023/A:1021813303130 PG 3 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 341RE UT WOS:000088602700008 ER PT J AU Meade, DM AF Meade, DM TI Road map for a modular magnetic fusion program SO JOURNAL OF FUSION ENERGY LA English DT Article DE fusion; ignition AB During the past several decades magnetic fusion has made outstanding progress in understanding the science of fusion plasmas, the achievement of actual fusion plasmas and the development of key fusion technologies. Magnetic fusion is now technically ready to take the next step: the study of high gain fusion plasmas, the optimization of fusion plasmas and the continued development and integration of fusion technology. However, each of these objectives requires significant resources since the tests are now being done at the energy production scale. This paper describes a modular approach that addresses these objectives in specialized facilities that reduces the technical risk and lowers cost for near term facilities needed to address critical issues. C1 Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Meade, DM (reprint author), Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 7 TC 0 Z9 0 U1 0 U2 1 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0164-0313 J9 J FUSION ENERG JI J. Fusion Energy PD JUN PY 1998 VL 17 IS 2 BP 125 EP 131 DI 10.1023/A:1021817404039 PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 341RE UT WOS:000088602700010 ER PT J AU Lin, N Kellogg, PJ MacDowall, RJ Scime, EE Balogh, A Forsyth, RJ McComas, DJ Phillips, JL AF Lin, N Kellogg, PJ MacDowall, RJ Scime, EE Balogh, A Forsyth, RJ McComas, DJ Phillips, JL TI Very low frequency waves in the heliosphere: Ulysses observations SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ELECTRON HEAT-FLUX; SOLAR-WIND; INTERPLANETARY SHOCKS; MAGNETIC-FIELD; ECLIPTIC-PLANE; WHISTLER WAVES; LATITUDES; RADIO AB An overall profile of plasma wave activity in a frequency range of 0.2 to 448 Hz in the solar wind is presented using 6 years of Ulysses data which cover a large range of heliographic latitudes (0 degrees to +/- 80 degrees) at distances from 1 to 5 AU from the Sun. The spacecraft has continuously observed wave activity with peak power below the local electron cyclotron frequency f(ce). Four distinct types of fluctuation phenomena have been observed: (1) enhanced electromagnetic fluctuations associated with the interplanetary shocks and heliospheric current sheet crossings and other solar wind turbulence; (2) enhanced electromagnetic fluctuations associated with compression regions of high-speed stream interfaces, which were observed in periods of increasing solar wind velocity; (3) electric fluctuations associated with the expanding solar wind, which were observed in periods of decreasing solar wind velocity; and (4) enhanced electric fluctuations in the high-latitude fast solar wind plasma. The fourth type of wave activity was observed nearly continuously with the relative power observed peaked near the local f(ce). The first three types of waves were observed in the heliomagnetic streamer belt flows, where the spacecraft frequently encountered enhanced solar mind turbulence, interplanetary shocks, and current sheet crossings. The electromagnetic wave bursts (types 1 and 2) are likely to be whistler mode. The occurrences of apparently electrostatic waves during periods of expanding solar wind are coincident with significant reductions in the electron heat flux intensity. The generation mechanism of these electrostatic waves is still under investigation, but the observations may imply that these waves reduce the intensity of the heat flux through enhanced wave particle scattering associated with a heat flux instability. C1 Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. Univ London Imperial Coll Sci Technol & Med, London, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. W Virginia Univ, Dept Phys, Morgantown, WV 26506 USA. RP Lin, N (reprint author), Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. EM lin@waves.space.umn.edu; kellogg@waves.space.umn.edu; xrrjm@leprjm.gsfc.nasa.gov; scime@wvnvaxa.wvnet.edu; a.balogh@ic.ac.uk; r.forsyth@ic.ac.uk; dmccomas@lanl.gov RI MacDowall, Robert/D-2773-2012 NR 38 TC 25 Z9 25 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUN 1 PY 1998 VL 103 IS A6 BP 12023 EP 12035 DI 10.1029/98JA00764 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZQ564 UT WOS:000073880700039 ER PT J AU Raimondo, SM Rowe, CL Congdon, JD AF Raimondo, SM Rowe, CL Congdon, JD TI Exposure to coal ash impacts swimming performance and predator avoidance in larval bullfrogs (Rana catesbeiana) SO JOURNAL OF HERPETOLOGY LA English DT Article ID FLY-ASH; TEMPORARY PONDS; LOW PH; TADPOLES; AMPHIBIANS; SUSCEPTIBILITY; ECOSYSTEMS; ALUMINUM; EMBRYOS C1 Univ Georgia, Savannah River Ecol Lab, Aiken, SC 29802 USA. RP Rowe, CL (reprint author), Univ Georgia, Savannah River Ecol Lab, PO Drawer E, Aiken, SC 29802 USA. RI Rowe, Christopher/D-5271-2012 NR 23 TC 62 Z9 63 U1 2 U2 12 PU SOC STUDY AMPHIBIANS REPTILES PI ST LOUIS PA C/O ROBERT D ALDRIDGE, ST LOUIS UNIV, DEPT BIOLOGY, 3507 LACLEDE, ST LOUIS, MO 63103 USA SN 0022-1511 J9 J HERPETOL JI J. Herpetol. PD JUN PY 1998 VL 32 IS 2 BP 289 EP 292 DI 10.2307/1565313 PG 4 WC Zoology SC Zoology GA ZT261 UT WOS:000074066900023 ER PT J AU Lorusso, GF Capozzi, V Staehli, JL AF Lorusso, GF Capozzi, V Staehli, JL TI Photoluminescence excitation spectra of disordered superlattices SO JOURNAL OF LUMINESCENCE LA English DT Article DE disordered systems; quantum wells; electronic states (localized) ID LOCALIZATION AB We investigate photoluminescence excitation (PLE) and selective photoluminescence (SPL) of ordered and disordered superlattices, showing that the coexistence of localized and extended states in disordered superlattices produces a dramatic dependence of the PLE spectra on the detection energy. We demonstrate that the PLE of disordered superlattices gives ambiguous information on joint density of states, and we use SPL in order to show that this effect is a consequence of the localization and of the lack of thermal equilibrium in disordered systems. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Bari, Dipartmento Fis, I-70126 Bari, Italy. INFM, I-70126 Bari, Italy. Ecole Polytech Fed Lausanne, Dept Phys, CH-1015 Lausanne, Switzerland. RP Lorusso, GF (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-2313 J9 J LUMIN JI J. Lumines. PD JUN PY 1998 VL 78 IS 4 BP 259 EP 264 DI 10.1016/S0022-2313(98)00004-0 PG 6 WC Optics SC Optics GA ZV487 UT WOS:000074309500004 ER PT J AU Gatteschi, D Lascialfari, A Borsa, F AF Gatteschi, D Lascialfari, A Borsa, F TI H-1 NMR study of the spin dynamics in the superparamagnetic octanuclear iron cluster Fe8 SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article; Proceedings Paper CT ICM 97 Meeting CY 1997 CL CAIRNS, AUSTRALIA SP ICM DE clusters; NMR-relaxation; relaxation time; spin fluctuations AB The eight iron (III) S = 5/2 cluster Fe8, was studied by H-1 NMR and relaxation rate measurements. We directed our experimental efforts to the analysis of the nuclear spin-lattice relaxation rate T-1(-1) which presents a broad maximum at T > 100 K for all the NMR frequencies used. We discuss the temperature and frequency dependence of the relaxation rate in terms of the slow fluctuations of the local Fe magnetic moment and we try to relate the local dynamics observed by NMR with the macroscopic relaxation of the magnetization measured by AC susceptibility and Mossbauer experiments. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Florence, Dipartimento Chim, I-50144 Florence, Italy. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. Dept Phys A Volta, I-27100 Pavia, Italy. RP Gatteschi, D (reprint author), Univ Florence, Dipartimento Chim, Via Maragliano 75-77, I-50144 Florence, Italy. RI Gatteschi, Dante/B-5429-2008; OI Gatteschi, Dante/0000-0002-4859-4317 NR 7 TC 7 Z9 7 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD JUN PY 1998 VL 185 IS 2 BP 238 EP 240 DI 10.1016/S0304-8853(97)00711-7 PG 3 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA ZQ849 UT WOS:000073909200017 ER PT J AU Thoms, H Epple, M Froba, M Wong, J Reller, A AF Thoms, H Epple, M Froba, M Wong, J Reller, A TI Metal diolates: useful precursors for tailor-made oxides prepared at low temperatures SO JOURNAL OF MATERIALS CHEMISTRY LA English DT Article ID RAY AB Diolates of titanium and heterometallic diolates of the combinations Mg/Si, Mg/Ti, Mg/Zr and Ti/Si were prepared by reacting alcoholates [e.g. Ti(OC2H5)(4), Mg(OCH3)(2) . CH3OH] with alpha,omega-diols like pentane-1,5-diol. The resulting diolates are probably of polymeric nature and do not form single crystals. Structural information was obtained by infrared spectroscopy, thermal analysis and X-ray absorption spectroscopy at the Mg and Si K-edges. Thermal decomposition of such diolates led to oxides with distinct morphology at comparatively low temperatures (540-800 degrees C). For the heterometallic diolates the thermal decomposition in most cases led to binary, sometimes metastable oxides. The morphology of the oxides strongly depended on the nature of the precursor. C1 Univ Hamburg, Inst Inorgan & Appl Chem, D-20146 Hamburg, Germany. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Reller, A (reprint author), Univ Hamburg, Inst Inorgan & Appl Chem, Martin Luther King Pl 6, D-20146 Hamburg, Germany. EM reller@xray.chemie.uni-hamburg.de RI Froba, Michael/B-2888-2010 NR 22 TC 23 Z9 23 U1 0 U2 0 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON ROAD, CAMBRIDGE CB4 4WF, CAMBS, ENGLAND SN 0959-9428 J9 J MATER CHEM JI J. Mater. Chem. PD JUN PY 1998 VL 8 IS 6 BP 1447 EP 1451 DI 10.1039/a801263f PG 5 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA ZU197 UT WOS:000074172000023 ER PT J AU Grohmann, I Hess, A Kemnitz, E Fentrup, W Unger, WES Wong, J Rowen, M Tanaka, T Froba, M AF Grohmann, I Hess, A Kemnitz, E Fentrup, W Unger, WES Wong, J Rowen, M Tanaka, T Froba, M TI XANES investigations and catalytic properties of coprecipitated AlF3/MgF2 phases SO JOURNAL OF MATERIALS CHEMISTRY LA English DT Article ID SURFACE-AREA ALUMINA; AMBIENT-TEMPERATURE; GAMMA-ALUMINA; 1,1,1-TRICHLOROETHANE; OXIDE; DECOMPOSITION; FLUORINATION; EXCHANGE; BEHAVIOR AB Stepwise replacement of aluminium by magnesium in beta-AlF3 phases leads to considerable alterations in the structure and surface properties of the calcination products of co-precipitates. This is accompanied by significant changes in the catalytic activity for heterogeneous chlorine/fluorine exchange reactions. The maximum catalytic activity is reached between 10 and 20 atom% magnesium doping. Due to the decrease of the strength of Lewis acid sites with further increasing the Mg content, the catalytic activity is more and more diminished. The XRD patterns indicate a loss of crystallinity for beta-AlF3 with increasing Mg content. From Mg K-edge XANES and Al K-edge XANES spectra of Mg added beta-AlF3 phases one can conclude a partial incorporation of Mg into the beta-AlF3 lattice. Furthermore, a partial electron transfer from magnesium to the beta-AlF3 lattice resulting in an increased electron deficiency (increased Lewis acidity) at low Mg concentrations can be stated, a result which correlates well with the increased catalytic activity observed for co-precipitated phases with lower Mg contents. The insertion of Mg into the beta-AlF3 lattice is also supported by XPS studies on the same samples which show an increase of the modified Auger parameter for magnesium of about 0.4 eV, which indicates a change of the chemical environment of the ionized magnesium atom. C1 Humboldt Univ, Inst Chem, D-10115 Berlin, Germany. Humboldt Univ, Inst Phys, EES, D-10115 Berlin, Germany. Bundesanstalt Mat Forsch & Prufung, D-12205 Berlin, Germany. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. Natl Inst Res Inorgan Mat, Tsukuba, Ibaraki 305, Japan. Univ Hamburg, Inst Anorgan & Angew Chem, D-20146 Hamburg, Germany. RP Kemnitz, E (reprint author), Humboldt Univ, Inst Chem, Hessische Str 1-2, D-10115 Berlin, Germany. RI Froba, Michael/B-2888-2010; Unger, Wolfgang/A-9317-2009 OI Unger, Wolfgang/0000-0002-7670-4042 NR 19 TC 5 Z9 5 U1 1 U2 5 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON ROAD, CAMBRIDGE CB4 4WF, CAMBS, ENGLAND SN 0959-9428 J9 J MATER CHEM JI J. Mater. Chem. PD JUN PY 1998 VL 8 IS 6 BP 1453 EP 1457 DI 10.1039/a801131a PG 5 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA ZU197 UT WOS:000074172000024 ER PT J AU Jensen, JA Laabs, FC Chumbley, LS AF Jensen, JA Laabs, FC Chumbley, LS TI Microstructure of heavily deformed magnesium-lithium composites containing steel fibers SO JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE LA English DT Article DE in-situ composites; metal matrix composites; microscopy; steel wool ID DEFORMATION; STRENGTH; TITANIUM; YTTRIUM; ALLOYS AB The microstructure of deformation-processed metal-metal composites (DMMC) of Mg-Li alloys containing steel reinforcing fibers was characterized to correlate the fiber size to the deformation strain and mechanical properties of the composite material, Micrographs taken using scanning and transmission electron microscopy techniques revealed fiber sizes larger than predicted from the deformation applied to the bulk composite, Deformation strain in the fibers, therefore, was less than in the bulk material. Measurements from SEM and TEM micrographs were used to calculate the actual deformation strain present in the fibers. This strain was then used to adjust rule-of-mixture (ROM) predictions of the strength of the composite material. However, the experimental strengths of these materials were still less than the adjusted ROM values, potentially due to the presence of fibers considerably larger than the average size measured stereologically. Of the many models used to describe the strengthening observed in DMMC materials, the Hall-Fetch relationship best describes the experimental data. Details of the strengthening models are discussed in relation to these composite materials. C1 Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. RP Jensen, JA (reprint author), Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA. EM jensen_jeff_a@cat.com NR 23 TC 3 Z9 6 U1 3 U2 4 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 1059-9495 J9 J MATER ENG PERFORM JI J. Mater. Eng. Perform. PD JUN PY 1998 VL 7 IS 3 BP 375 EP 384 DI 10.1361/105994998770347828 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA ZQ600 UT WOS:000073884300012 ER PT J AU Heffelfinger, JR Medlin, DL McCarty, KF AF Heffelfinger, JR Medlin, DL McCarty, KF TI Preparation of wurtzitic AlN thin films with a novel crystallographic alignment on MgO substrates by molecular-beam epitaxy SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID ALUMINUM NITRIDE; GROWTH AB Thin films of wurtzitic AW have been deposited by molecular-beam epitaxy onto (001) oriented MgO substrates, The films are epitactic and align with the (2 (1) over bar (1) over bar 0)(AlN) \\ (220)(MgO) and the [01 (1) over bar 1](AlN) \\ [001](MgO), as evidenced by transmission electron microscopy, This configuration, which matches a close-packed direction of the film and substrate, allows for growth of two symmetrically equivalent orientation variants of the AlN film, These variants are distinguished by a 90 degrees rotation about the [01 (1) over bar 1](AlN) direction that is normal to the substrate surface. Each variant also aligns the (0 (1) over bar 12)(AlN) \\ (2 (2) over bar 0)(MgO) and the (1 (1) over bar 01)(AlN) to within 5 degrees of being parallel to the (200)(MgO). The microstructure of the AlN films and origins of these novel alignments are discussed. C1 Sandia Natl Labs, Ctr Mat Sci & Engn, Livermore, CA 94551 USA. RP Heffelfinger, JR (reprint author), Hutchinson Technol, 40 W Highland Pk,Mail Stop 707, Hutchinson, MN 55350 USA. RI McCarty, Kevin/F-9368-2012 OI McCarty, Kevin/0000-0002-8601-079X NR 16 TC 3 Z9 3 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD JUN PY 1998 VL 13 IS 6 BP 1414 EP 1417 DI 10.1557/JMR.1998.0200 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA ZT232 UT WOS:000074063800002 ER PT J AU Weber, WJ Ewing, RC Catlow, CRA de la Rubia, TD Hobbs, LW Kinoshita, C Matzke, H Motta, AT Nastasi, M Salje, EKH Vance, ER Zinkle, SJ AF Weber, WJ Ewing, RC Catlow, CRA de la Rubia, TD Hobbs, LW Kinoshita, C Matzke, H Motta, AT Nastasi, M Salje, EKH Vance, ER Zinkle, SJ TI Radiation effects in crystalline ceramics for the immobilization of high-level nuclear waste and plutonium SO JOURNAL OF MATERIALS RESEARCH LA English DT Review ID IRRADIATION-INDUCED AMORPHIZATION; ALPHA-RECOIL DAMAGE; ANGULAR-CORRELATION SPECTROSCOPY; BEAM-INDUCED AMORPHIZATION; TO-AMORPHOUS TRANSITION; SIC SINGLE-CRYSTALS; DECAY EVENT DAMAGE; PU-SUBSTITUTED ZIRCONOLITE; SOLID-STATE AMORPHIZATION; PYROCHLORE GROUP MINERALS AB This review provides a comprehensive evaluation of the state-of-knowledge of radiation effects in crystalline ceramics that may be used for the immobilization of high-level nuclear waste and plutonium. The current understanding of radiation damage processes, defect generation, microstructure development, theoretical methods, and experimental methods are reviewed. Fundamental scientific and technological issues that offer opportunities for research are identified. The most important issue is the need for an understanding of the radiation-induced structural changes at the atomic, microscopic, and macroscopic levels, and the effect of these changes on the release rates of radionuclides during corrosion. C1 Pacific NW Lab, Richland, WA 99352 USA. Univ Michigan, Ann Arbor, MI 48109 USA. UCL Royal Inst Great Britain, London W1X 4BS, England. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA. Kyushu Univ, Dept Nucl Engn, Fukuoka 812, Japan. Commiss European Communities, Joint Res Ctr, Inst Transuranium Elements, D-76125 Karlsruhe, Germany. Penn State Univ, Dept Nucl Engn, University Pk, PA 16802 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Cambridge, Dept Earth Sci, Cambridge CB2 3EQ, England. ANSTO, Mater Div, Menai, NSW, Australia. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Pacific NW Lab, POB 999,MS K2-44, Richland, WA 99352 USA. RI Weber, William/A-4177-2008; Salje, Ekhard/M-2931-2013; OI Weber, William/0000-0002-9017-7365; Salje, Ekhard/0000-0002-8781-6154; Zinkle, Steven/0000-0003-2890-6915 NR 395 TC 572 Z9 590 U1 21 U2 189 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0884-2914 EI 2044-5326 J9 J MATER RES JI J. Mater. Res. PD JUN PY 1998 VL 13 IS 6 BP 1434 EP 1484 DI 10.1557/JMR.1998.0205 PG 51 WC Materials Science, Multidisciplinary SC Materials Science GA ZT232 UT WOS:000074063800007 ER PT J AU Kung, H Lu, YC Bartlett, AH Castro, RG Petrovic, JJ Shtessel, E AF Kung, H Lu, YC Bartlett, AH Castro, RG Petrovic, JJ Shtessel, E TI Structural characterization of combustion synthesized MoSi2-Si3N4 composite powders and plasma sprayed MoSi2-Si3N4 composites SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID HIGH-TEMPERATURE SYNTHESIS; MOSI2 AB A systematic structural characterization has been conducted on combustion synthesized MoSi2-Si3N4 powders and plasma sprayed composites by transmission electron microscopy (TEM). The powders are cleaner and with little surface oxide contamination than most commercial powders. The distribution of the two phases can be tailored by modifying the synthesis conditions, which has resulted in improved retention of Si3N4 after plasma spraying. TEM studies performed on deformed composites indicate a strong link between even dispersion of second phases and enhanced dislocation plasticity in the plasma sprayed composites. C1 Univ Calif Los Alamos Natl Lab, Mat Sci & Technol Div, Los Alamos, NM 87545 USA. Exotherm Corp, Camden, NJ USA. RP Kung, H (reprint author), Univ Calif Los Alamos Natl Lab, Mat Sci & Technol Div, POB 1663, Los Alamos, NM 87545 USA. NR 17 TC 10 Z9 10 U1 1 U2 2 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD JUN PY 1998 VL 13 IS 6 BP 1522 EP 1529 DI 10.1557/JMR.1998.0212 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA ZT232 UT WOS:000074063800014 ER PT J AU Cao, ZC Lee, BI Samuels, WD Wang, LQ Exarhos, GJ AF Cao, ZC Lee, BI Samuels, WD Wang, LQ Exarhos, GJ TI Sol-gel synthesis of phosphate ceramic composites II SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID SILICON; GLASS; PHOSPHORUS; EVOLUTION; SI-29 AB Phosphate ceramics were synthesized using sol-gel technique of direct reaction of P2O5 With tetraethoxy silane (TEOS) or titanium tetraethoxide (Ti(OEt)(4)). The reaction mechanism of P2O5 and TEOS was deduced using liquid and solid-state NMR. Hexacoordinated silicon in phosphosilicate gels was observed. A specially structured titanium phosphate-layered Ti(HPO4)(2).2H(2)O was synthesized for the first time through the sol-gel method. The gelation process and phase transformations were investigated. C1 Clemson Univ, Dept Ceram & Mat Engn, Clemson, SC 29634 USA. Pacific NW Lab, Richland, WA 99352 USA. RP Lee, BI (reprint author), Clemson Univ, Dept Ceram & Mat Engn, Clemson, SC 29634 USA. NR 28 TC 14 Z9 14 U1 1 U2 1 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD JUN PY 1998 VL 13 IS 6 BP 1553 EP 1559 DI 10.1557/JMR.1998.0216 PG 7 WC Materials Science, Multidisciplinary SC Materials Science GA ZT232 UT WOS:000074063800018 ER PT J AU Tsu, IF Bai, GR Foster, CM Merkle, KL Liu, KC AF Tsu, IF Bai, GR Foster, CM Merkle, KL Liu, KC TI Grain morphology and cation composition heterogeneity of Pb(ZrxTi1-x)O-3 thin films deposited by metal-organic chemical vapor deposition SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID ZIRCONATE-TITANATE FILMS; ELECTRICAL-PROPERTIES; METALLOORGANIC DECOMPOSITION; SOLID FILMS; GEL; GROWTH; MICROSTRUCTURE; STOICHIOMETRY; MOCVD; CAPACITORS AB The preferred orientation, grain morphology, and composition heterogeneity of the polycrystalline Pb(ZrxTi1-x)O-3 (PZT) thin films were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), and x-ray energy dispersive spectroscopy (EDS). PZT thin films with nominal x = 0.5 were grown by metal-organic chemical vapor deposition (MOCVD) on (110)- and (101)-textured RuO2 bottom electrodes at temperatures less than or equal to 525 degrees C. Columnar grain microstructure with strongly faceted surface morphology was observed in both films. The grain morphology and surface roughness of the PZT films were observed to depend on those of the underlying RuO2 layers. TEM-EDS analysis shows notable cation composition heterogeneity in length scales of 0.2-2 mu m. Pronounced Pb composition deficiency and heterogeneity were also observed in PZT/(110)RuO2 in length scales above 40 mu m. The grain morphology and cation heterogeneity of the PZT films are discussed on the basis of diffusion-limited columnar growth mechanism. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Univ Wisconsin, Water Chem Program, Madison, WI 53706 USA. RP Tsu, IF (reprint author), Seagate Technol, Recording Head Grp, Minneapolis, MN 55437 USA. NR 41 TC 10 Z9 10 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 JUN PY 1998 VL 13 IS 6 BP 1614 EP 1625 DI 10.1557/JMR.1998.0222 PG 12 WC Materials Science, Multidisciplinary SC Materials Science GA ZT232 UT WOS:000074063800024 ER PT J AU Cendra, H Holm, DD Hoyle, MJW Marsden, JE AF Cendra, H Holm, DD Hoyle, MJW Marsden, JE TI The Maxwell-Vlasov equations in Euler-Poincare form SO JOURNAL OF MATHEMATICAL PHYSICS LA English DT Article ID POISSON SYSTEM; 3 DIMENSIONS; STABILITY; PRINCIPLES; EQUILIBRIA; PLASMA AB Low's well-known action principle for the Maxwell-Vlasov equations of ideal plasma dynamics was originally expressed in terms of a mixture of Eulerian and Lagrangian variables. By imposing suitable constraints on the variations and analyzing invariance properties of the Lagrangian, as one does for the Euler equations for the rigid body and ideal fluids, we first transform this action principle into purely Eulerian variables. Hamilton's principle for the Eulerian description of Low's action principle then casts the Maxwell-Vlasov equations into Euler-Poincare form for right invariant motion on the diffeomorphism group of position-velocity phase space, R-6. Legendre transforming the Eulerian form of Low's action principle produces the Hamiltonian formulation of these equations in the Eulerian description. Since it arises from Euler-Poincare equations, this Hamiltonian formulation can be written in terms of a Poisson structure that contains the Lie-Poisson bracket on the dual of a semidirect product Lie algebra. Because of degeneracies in the Lagrangian, the Legendre transform is dealt with using the Dirac theory of constraints. Another Maxwell-Vlasov Poisson structure is known, whose ingredients are the Lie-Poisson bracket on the dual of the Lie algebra of symplectomorphisms of phase space and the Born-Infeld brackets for the Maxwell field. We discuss the relationship between these two Hamiltonian formulations. We also discuss the general Kelvin-Noether theorem for Euler-Poincare equations and its meaning in the plasma context. (C) 1998 American Institute of Physics. C1 CALTECH, Pasadena, CA 91125 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Calif Santa Cruz, Dept Math, Santa Cruz, CA 95064 USA. Univ Nacl Sur, RA-8000 Bahia Blanca, Argentina. RP Cendra, H (reprint author), CALTECH, Pasadena, CA 91125 USA. OI Holm, Darryl D/0000-0001-6362-9912 NR 34 TC 42 Z9 42 U1 1 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0022-2488 J9 J MATH PHYS JI J. Math. Phys. PD JUN PY 1998 VL 39 IS 6 BP 3138 EP 3157 DI 10.1063/1.532244 PG 20 WC Physics, Mathematical SC Physics GA 108KC UT WOS:000075264200011 ER PT J AU Heitzer, A Applegate, B Kehrmeyer, S Pinkart, H Webb, OF Phelps, TJ White, DC Sayler, GS AF Heitzer, A Applegate, B Kehrmeyer, S Pinkart, H Webb, OF Phelps, TJ White, DC Sayler, GS TI Physiological considerations of environmental applications of lux reporter fusions SO JOURNAL OF MICROBIOLOGICAL METHODS LA English DT Article DE bioluminescence; Pseudomonas fluorescens; naphthalene ID ESCHERICHIA-COLI; SALICYLATE BIOAVAILABILITY; BACTERIAL BIOLUMINESCENCE; NAPHTHALENE; CATABOLISM; NAH; PHENANTHRENE; INDUCTION; EXPOSURE; ACIDS AB The performance of the bioluminescent reporter bacterium Pseudomonas fluorescens HK44, which contains a nahG-luxCDABE fusion for naphthalene catabolism and bioavailability was investigated for environmental samples and mixed contaminants, For aqueous extracts from fuel hydrocarbon-contaminated soils, a reproducible bioluminescence response was obtained, which coincided with, but overestimated the presence of naphthalene. Therefore, the strain's bioluminescence response to mixed contaminants was investigated further. The strain showed a linear correlation between bioluminescence and the amount of JP-4 jet fuel present in an aqueous solution, representing a mixture of compounds including naphthalene. However, some non-inducing organic solvents such as toluene, p-xylene and acetone caused a significant bioluminescence increase as well. The analysis of nah-lux mRNA from cells exposed to toluene revealed that the bioluminescence response was not due to increased nahG-luxCDABE gene expression, whereas increased lux mRNA levels were found with exposure to naphthalene or JP-4 jet fuel. While different mixture combinations of solvents resulted in either additive or intermediate effects, the combination of naphthalene and solvent resulted in a synergistic effect on the bioluminescence response. The addition of n-decanal, a substrate for luciferase, showed that the cells were aldehyde-limited. If aldehyde was added, only the presence of naphthalene caused a significantly increased bioluminescence response over the control. The solvent effects were dependent on the physiological status of the reporter culture and were present in growing, but not in resting cell cultures. It was postulated that the increase in bioluminescence after exposure to solvents was due to changed fatty acid synthesis patterns affecting the aldehyde supply for the bioluminescence reaction. Exposure to toluene resulted in altered membrane fatty acid composition and release of fatty acids from the cells. Exposure to n-alkanes resulted in minor changes in the bioluminescence response, whereas, exposure to heavy metals or cyanide resulted in significant reductions in the overall bioluminescence. These results demonstrate the utility of bioluminescent reporter bacteria for environmental applications, as well as the need for adequate experimental controls in interpreting environmental sensing data. (C) 1998 Elsevier Science B.V. C1 Univ Tennessee, Ctr Environm Biotechnol, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Sayler, GS (reprint author), Univ Tennessee, Ctr Environm Biotechnol, 676 Dabney Hall, Knoxville, TN 37996 USA. EM SAYLER@utk.edu RI phelps, tommy/A-5244-2011 NR 33 TC 62 Z9 64 U1 1 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-7012 J9 J MICROBIOL METH JI J. Microbiol. Methods PD JUN PY 1998 VL 33 IS 1 BP 45 EP 57 DI 10.1016/S0167-7012(98)00043-8 PG 13 WC Biochemical Research Methods; Microbiology SC Biochemistry & Molecular Biology; Microbiology GA 104VD UT WOS:000075035800005 ER PT J AU Castner, EW Maroncelli, M AF Castner, EW Maroncelli, M TI Solvent dynamics derived from optical Kerr effect, dielectric dispersion, and time-resolved Stokes shift measurements: An empirical comparison SO JOURNAL OF MOLECULAR LIQUIDS LA English DT Review ID ULTRAFAST SOLVATION DYNAMICS; SURROGATE HAMILTONIAN DESCRIPTION; DEPOLARIZED RAYLEIGH-SCATTERING; STIMULATED RAMAN-SCATTERING; LIQUID CARBON-DISULFIDE; LIGHT-SCATTERING; MOLECULAR-DYNAMICS; INTERMOLECULAR DYNAMICS; POLAR LIQUIDS; ORIENTATIONAL RELAXATION AB Data from the optical Kerr effect, time-resolved Stokes shift, and dielectric dispersion experiments on 21 common room temperature solvents are collected and compared. The correlation functions of the collective variables (polarizability, solvation energy, and dipole moment fluctations) responsible for each observable are first extracted from the experimental data and compared directly. In any given solvent the decay times of these various correlation functions are often vastly different. Such differences mainly result from the fact that intermolecular correlations affect the collective variables sampled by each technique in a different manner. To compare dynamics at a more basic level, power law relations are applied in an attempt to account for these correlations and to examine the extent to which the collective dynamics in these three experiments can be viewed as arising from the same underlying single-particle motions (primarily rotations). The Stokes shift and dielectric correlation functions can be reasonably inter-related in this manner, but the polarizability anisotropy monitored with Kerr experiments cannot be as simply related to the former two dynamics, probably due to the importance of collision-induced effects in the latter case. (C) 1998 Elsevier Science B.V. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Penn State Univ, Dept Chem, University Pk, PA 16802 USA. RP Castner, EW (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RI Maroncelli, Mark/A-1800-2012 NR 142 TC 148 Z9 148 U1 3 U2 39 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-7322 J9 J MOL LIQ JI J. Mol. Liq. PD JUN PY 1998 VL 77 IS 1-3 BP 1 EP 36 DI 10.1016/S0167-7322(98)00066-X PG 36 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZW741 UT WOS:000074443100002 ER PT J AU Sales, BC Otaigbe, JU Beall, GH Boatner, LA Ramey, JO AF Sales, BC Otaigbe, JU Beall, GH Boatner, LA Ramey, JO TI Structure of zinc polyphosphate glasses SO JOURNAL OF NON-CRYSTALLINE SOLIDS LA English DT Article ID X-RAY-DIFFRACTION; PHOSPHATE-GLASSES; LEAD PYROPHOSPHATE; SPECTROSCOPY; SCATTERING; STATE; XPS AB The technique of high-performance liquid chromatography (HPLC) has been used to determine the distributions of phosphate-anion chains and rings in a variety of zinc-phosphate-based glasses. The phosphate-anion distributions in simple binary zinc phosphate glasses are compared to those found in multi-cation alkali-zine phosphate glasses. Multi-cation zinc phosphate glasses are chemically durable and can be tailored to exhibit transition temperatures sufficiently low for co-processing with a variety of plastics to form novel organic-inorganic composite materials. The intermediate range order in the multi-cation glasses is found to be similar to that measured in the binary zinc-phosphate glasses. Scanning calorimetry measurements indicate, however, that the multi-cation glasses are more resistant to crystallization than the binary glasses. The fraction of phosphorus sites with 2 (Q(2)), 1 (Q(1)) and 0 (Q(0)) bridging oxygen, as well as the ratio of bridging to non-bridging oxygen (BO/NBO), are obtained from the chromatograms. Structural data for the zinc phosphate glasses obtained using HPLC are compared to results reported in the literature that were deduced using more-traditional solid-state techniques such as NMR, XPS, and Raman spectroscopy. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. Corning Inc, Sci & Technol Grp, Corning, NY 14831 USA. RP Sales, BC (reprint author), Oak Ridge Natl Lab, MS-6056,POB 6056, Oak Ridge, TN 37831 USA. EM vb4@ornl.gov RI Boatner, Lynn/I-6428-2013 OI Boatner, Lynn/0000-0002-0235-7594 NR 23 TC 33 Z9 33 U1 2 U2 19 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3093 EI 1873-4812 J9 J NON-CRYST SOLIDS JI J. Non-Cryst. Solids PD JUN PY 1998 VL 226 IS 3 BP 287 EP 293 DI 10.1016/S0022-3093(98)00415-3 PG 7 WC Materials Science, Ceramics; Materials Science, Multidisciplinary SC Materials Science GA ZX380 UT WOS:000074509900011 ER PT J AU Cooke, DW Bennett, BL Farnum, EH Thomas, DE Portis, AM AF Cooke, DW Bennett, BL Farnum, EH Thomas, DE Portis, AM TI Radioluminescence in amorphous silica: temperature dependence and relaxation SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID SELF-TRAPPED EXCITON; OPTICAL-ABSORPTION; CRYSTALLINE SIO2; SYNTHETIC SILICA; LUMINESCENCE; FIBERS; QUARTZ; RADIATION; DIOXIDE; ENERGY AB Radioluminescence measurements on preform and fiber amorphous silica specimens have been made in the temperature interval 6 to 300 K and wavelength regime 300 to 800 nm. A typical spectrum consists of peaks at similar to 550 (main band) and similar to 650 (secondary band) nm, which are associated with self-trapped excitons and nonbridging oxygen hole centers of the silica lattice, respectively. Radioluminescence from the main band decays with increasing temperature and becomes undetectable in the 130 to 170 K range, consistent with the decay of self-trapped holes. Assuming the decrease in radioluminescence with temperature to be due to quenching of self-trapped exciton radiative recombination, with a spread in quenching barrier energy, we derive an expression of the form L(T)=L(0)/[1 + AT + BT2 + CT3], which yields an excellent fit to the experimental data. An observed time-dependent relaxation of radioluminescence is associated with the enhancement of nonradiative recombination. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RP Cooke, DW (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, MST-8,MS E546, Los Alamos, NM 87545 USA. NR 37 TC 4 Z9 4 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD JUN PY 1998 VL 255 IS 2-3 BP 180 EP 188 DI 10.1016/S0022-3115(98)00027-0 PG 9 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA ZY384 UT WOS:000074615900010 ER PT J AU Balooch, M Siekhaus, WJ AF Balooch, M Siekhaus, WJ TI Reaction of hydrogen with uranium catalyzed by platinum clusters SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID ADSORPTION AB The surface-reaction of hydrogen with uranium in the presence of Pt clusters was studied using scanning tunnelling microscopy (STM). Uranium was deposited on highly oriented pyrolytic graphite (HOPG) and annealed at temperatures up to 1200 degrees C to obtain atomically flat surfaces. Platinum clusters were then formed using evaporation from a Pt source onto the surface and were subsequently annealed. As a result, hydrogen primarily attacked U in the vicinity of Pt clusters and formed hydride, which expanded non-linearly over time. A simple model to explain this expansion behavior is proposed. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. EM balooch1@1lnl.gov NR 8 TC 6 Z9 8 U1 2 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 EI 1873-4820 J9 J NUCL MATER JI J. Nucl. Mater. PD JUN PY 1998 VL 255 IS 2-3 BP 263 EP 268 DI 10.1016/S0022-3115(98)00028-2 PG 6 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA ZY384 UT WOS:000074615900018 ER PT J AU Hazlett, RD Chen, SY Soll, WE AF Hazlett, RD Chen, SY Soll, WE TI Wettability and rate effects on immiscible displacement: Lattice Boltzmann simulation in microtomographic images of reservoir rocks SO JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING LA English DT Article; Proceedings Paper CT 4th International Symposium on Evaluation of Reservoir Wettability and Its Effect on Oil Recovery CY SEP 11-13, 1996 CL MONTPELLIER, FRANCE DE relative permeability; network modeling; computational fluid dynamics; porous media; micro-imaging ID MODEL AB Pore networks derived from synchrotron X-ray microtomographic images of reservoir rocks were used to provide realistic,geometries for simulation of oil displacement by water. The Lattice Boltzmann Method was used to compute two-phase flow dynamics with constant pore geometry-but different pressure driving forces and imposed wettability distributions at the pore wall boundaries. Such examinations can be used to formulate more physically meaningful functional forms for multiphase flow relations to replace empirical constructs of relative permeability with only implicit dependencies on wettability and pore structure. Each simulation started with the same low initial water saturation distribution achieved by primary drainage network simulation in an initially strongly water-wet, reasonably homogeneous pore system. Mixed-wet scenarios were produced by altering the boundary conditions of those surfaces contacted by the non-wetting phase in the initial water distribution image. In one set of simulations comparing water-wet and mixed-wet boundary conditions, capillary numbers in the vicinity of 10(-4) were not low enough for differences in wettability to give markedly different displacement dynamics. Zn a second set of simulations, as the driving force for flow was reduced further, we saw differences in the fluid distributions, but only minor changes in the relative permeabilities extracted from simulation output. The biggest difference between waterflood simulations with different wettabilities appears to be the additional recovery possible after breakthrough in the mixed-wet scenario. Capillary pressure, and not relative permeability, controls whether or not a particular saturation state can be observed. It is therefore concluded that capturing wettability effects in capillary pressure relations is probably more important than trying to roll such effects into relative permeability functions. Wettability is expected to play a more important rob in heterogeneous systems. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Mobil Explorat & Prod Tech Ctr, Dallas, TX USA. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. RP Hazlett, RD (reprint author), Mobil Explorat & Prod Tech Ctr, Dallas, TX USA. RI Chen, Shiyi/A-3234-2010 NR 13 TC 34 Z9 34 U1 0 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-4105 J9 J PETROL SCI ENG JI J. Pet. Sci. Eng. PD JUN PY 1998 VL 20 IS 3-4 BP 167 EP 175 DI 10.1016/S0920-4105(98)00017-5 PG 9 WC Energy & Fuels; Engineering, Petroleum SC Energy & Fuels; Engineering GA ZX469 UT WOS:000074519200010 ER PT J AU Koike, J Kassner, ME Tate, RE Rosen, RS AF Koike, J Kassner, ME Tate, RE Rosen, RS TI The Nb-U (niobium-uranium) system SO JOURNAL OF PHASE EQUILIBRIA LA English DT Article C1 Tohoku Univ, Sendai, Miyagi 980, Japan. Oregon State Univ, Corvallis, OR 97331 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. RP Koike, J (reprint author), Tohoku Univ, Sendai, Miyagi 980, Japan. NR 42 TC 14 Z9 14 U1 1 U2 8 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 1054-9714 J9 J PHASE EQUILIB JI J. Phase Equilib. PD JUN PY 1998 VL 19 IS 3 BP 253 EP 260 DI 10.1361/105497198770342265 PG 8 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA ZR675 UT WOS:000074002500008 ER PT J AU Wu, CJ Klepeis, JE AF Wu, CJ Klepeis, JE TI The effect of Cl coverage on Si(100) surface reactivity: implications for Cl etching of Si SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID BONDING SITES; CHLORINE AB We have carried out first-principles calculations of the potential energy as a function of the distance from the Cl to the surface normal for various Si(100)-(2 x 1) surface sites. A comparison between the potential energies of the clean and Cl-covered (1 ML) surfaces indicates a significant change in Si surface reactivity. Our results suggest that it is critical to consider the effect of Cl coverage when simulating Cl plasma etching of Si With regard to the mechanism responsible for Cl etching of Si(100), we have ruled out the pathway where Cl penetrates into the Si substrate via adsorption on top of the exposed second-layer Si atoms. Both of the pathways via the exposed third-and fourth-layer Si atoms are found to be energetically possible. Finally, we have found, in contrast to the findings of previous theoretical studies, that the bridge bonded Cl structure is stable with the Si-Si dimer bond remaining intact, in agreement with the experimentally suggested structure. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Wu, CJ (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NR 19 TC 4 Z9 4 U1 1 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD JUN 1 PY 1998 VL 10 IS 21 BP 4515 EP 4522 DI 10.1088/0953-8984/10/21/009 PG 8 WC Physics, Condensed Matter SC Physics GA ZU415 UT WOS:000074194800009 ER PT J AU Staub, U Soderholm, L Osborn, R Goodwin, TJ Radousky, HB Shelton, RN AF Staub, U Soderholm, L Osborn, R Goodwin, TJ Radousky, HB Shelton, RN TI Magnetic ground state of Pr in (Pr1.5Ce0.5)Sr2Cu2NbO10-delta SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID CRYSTAL-FIELD; OXIDATION-STATE; LOCAL MAGNETISM; PR-141 NMR; PRBA2CU3O7; SUPPRESSION; 6-LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-7; SUPERCONDUCTIVITY; HYBRIDIZATION; CE AB Inelastic neutron scattering experiments were performed on (Pr1.5Ce0.5)Sr2Cu2 NbO10-delta to determine the magnetic ground state of the Pr ions. In this compound, superconductivity is suppressed by the presence of Pr ions. The magnetic ground state is found to be very similar to that in PrBa2Cu3Ox and Pb2Sr2PrCu3O8. However, the high energy spectrum has a stronger resemblance to that of Pr2-xCexCuO4, where the Pr ions see a very similar local structure. Therefore, a similar set of higher order crystalline-electric-field parameters and an inversion of B-0(2) can explain qualitatively the neutron spectra. The suppression of superconductivity and the quasi-tripler magnetic ground state support models which correlate the unusual magnetic properties with T-c suppression by Pr. C1 Paul Scherrer Inst, Swiss Light Source Project, CH-5232 Villigen, Switzerland. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Univ Calif Davis, Dept Phys, Davis, CA 95626 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Staub, U (reprint author), Paul Scherrer Inst, Swiss Light Source Project, CH-5232 Villigen, Switzerland. RI Osborn, Raymond/E-8676-2011; Staub, Urs/C-4914-2015 OI Osborn, Raymond/0000-0001-9565-3140; NR 32 TC 1 Z9 1 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD JUN 1 PY 1998 VL 10 IS 21 BP 4637 EP 4643 DI 10.1088/0953-8984/10/21/019 PG 7 WC Physics, Condensed Matter SC Physics GA ZU415 UT WOS:000074194800019 ER PT J AU Kryger, G Silman, I Sussman, JL AF Kryger, G Silman, I Sussman, JL TI Three-dimensional structure of a complex of E2020 with acetylcholinesterase from Torpedo californica SO JOURNAL OF PHYSIOLOGY-PARIS LA English DT Article DE Alzheimer's disease; drug design; peripheral site ID INDANONE BENZYLPIPERIDINE INHIBITORS; ACTIVE-SITE GORGE; HYDROCHLORIDE E2020; MOLECULAR-DYNAMICS; BINDING; ENZYME; SPECIFICITY; FIBRILS; SERIES AB The 3D structure of a complex of the anti-Alzheimer drug, E2020, also known as Aricept(R), with Torpedo californica acetylcholinesterase is reported. The X-ray structure, at 2.5 Angstrom resolution, shows that the elongated E2020 molecule spans the entire length of the active-site gorge of the enzyme. It thus interacts with both the 'anionic' subsite, at the bottom of the gorge, and with the peripheral anionic site, near its entrance, via aromatic stacking interactions with conserved aromatic residues. It does not interact directly with either the catalytic triad or with the 'oxyanion hole'. Although E2020 is a chiral molecule, and both the S and R enantiomers have similar affinity for the enzyme, only the R enantiomer is bound within the active-site gorge when the racemate is soaked into the crystal. The selectivity of E2020 for acetylcholinesterase, relative to butyrylcholinesterase, can be ascribed primarily to its interactions with Trp279 and Phe330, which are absent in the latter. ((C)Elsevier, Paris). C1 Weizmann Inst Sci, Dept Biol Struct, IL-76100 Rehovot, Israel. Weizmann Inst Sci, Dept Neurobiol, IL-76100 Rehovot, Israel. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Kryger, G (reprint author), Weizmann Inst Sci, Dept Biol Struct, IL-76100 Rehovot, Israel. OI Sussman, Joel/0000-0003-0306-3878 NR 23 TC 90 Z9 95 U1 1 U2 12 PU EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER PI PARIS CEDEX 15 PA 23 RUE LINOIS, 75724 PARIS CEDEX 15, FRANCE SN 0928-4257 J9 J PHYSIOLOGY-PARIS JI J. Physiol.-Paris PD JUN-AUG PY 1998 VL 92 IS 3-4 BP 191 EP 194 DI 10.1016/S0928-4257(98)80008-9 PG 4 WC Neurosciences; Physiology SC Neurosciences & Neurology; Physiology GA 120VR UT WOS:000075978500008 PM 9789806 ER PT J AU Kadish, A AF Kadish, A TI On the problem of source identification from far-field observations in hysteretic materials SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article ID PROPAGATION; SANDSTONE AB Propagation resulting from finite pulselength stresses applied at one end of a hysteretic material is analyzed using a propagation model containing a double modulus, or two-signal-speed, approximation of the stress-strain relation. The local signal speed is determined at any instant by both the value of stress and the sign of its time derivative (i.e., time-local history). It is shown that far-field waveforms do not determine unique source profiles. The propagation mechanism responsible for the ambiguity in source identification is common to broad classes of both local and global hysteretic stress-strain operators. Consequently, one may expect that it is typical of hysteretic materials that remote sources are not uniquely determined by observed waveforms. (C) 1998 Acoustical Society of America. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Kadish, A (reprint author), Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NR 9 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD JUN PY 1998 VL 103 IS 6 BP 3196 EP 3202 DI 10.1121/1.423075 PG 7 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA ZT999 UT WOS:000074151200007 ER PT J AU Ross, M Goodwin, R Watkins, R Wenzel, T Wang, MQ AF Ross, M Goodwin, R Watkins, R Wenzel, T Wang, MQ TI Real-world emissions from conventional passenger cars SO JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION LA English DT Article ID VEHICLE EMISSIONS; PROGRAM AB It has long been recognized that vehicles emit more pollutants than allowed under the new car emission standards. Further tightening of the certification standards based on existing test procedures does not directly address the largest sources of emissions. This study attempts to quantify vehicle emissions by source, in order to prioritize future policymaking. Several new sets of data are used in conjunction with regulatory emission models to characterize the lifetime emissions from the average Model Year (MY)93 vehicle. Special attention is paid to two of the largest sources of real-world emissions: (1) high-power driving by cars with properly functioning emissions controls, and (2) cars with malfunctioning emissions controls. Emissions are projected to MY2000 and 2010, based on estimates of the effectiveness of recently adopted and proposed regulatory policies. These new policies are projected to reduce total emissions substantially. C1 Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USA. Lawrence Berkeley Natl Lab, Energy Anal Program, Berkeley, CA 94720 USA. Argonne Natl Lab, Ctr Transportat Res, Argonne, IL 60439 USA. RP Ross, M (reprint author), Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USA. NR 33 TC 16 Z9 16 U1 0 U2 4 PU AIR & WASTE MANAGEMENT ASSOC PI PITTSBURGH PA ONE GATEWAY CENTER, THIRD FL, PITTSBURGH, PA 15222 USA SN 1047-3289 J9 J AIR WASTE MANAGE JI J. Air Waste Manage. Assoc. PD JUN PY 1998 VL 48 IS 6 BP 502 EP 515 PG 14 WC Engineering, Environmental; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA ZV301 UT WOS:000074290900003 PM 28075262 ER PT J AU Blanchard, CR Lin, HT Becher, PF AF Blanchard, CR Lin, HT Becher, PF TI Grain boundary sliding measurements during tensile creep of a single-phase alumina SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID POLYCRYSTALLINE ALUMINA; CAVITATION; SEGREGATION; NUCLEATION; CERAMICS; AL2O3 AB The grain boundary sliding (GBS) behavior of a single-phase (relatively coarse-grained) alumina material was studied after tensile creep experiments were performed at 1500 degrees C at stress levels of 20 and 35 MPa. Specimens tested at 35 MPa exhibited a number of modes of GBS, including Mode II (shear) displacements, Mode I (opening) displacements, out-of-plane sliding displacements, and in-plane grain rotation. Strains in the grain boundaries due to Mode II GBS ranged from 940% to 4400%. Average Mode II GBS displacements ranged from 0.08 to 0.29 mu m in samples tested for 120 and 480 min, respectively, at 35 MPa, The GBS displacements were shown to fit a Weibull distribution. Tensile creep under a 35 R MPa stress yielded a GBS rate of 9.5 x 10(-6) mu m/s, while the 20 MPa stress resulted in a GBS rate of 2.2 x 10-6 mu m/s. The average Mode II GBS displacements increased linearly with specimen strain, suggesting that GBS may play an important role in creep cavitation during tensile creep. The data also revealed that compatibility and constraint rules appear to govern GBS behavior during tensile creep. GBS behavior during compressive creep will be compared to the tensile creep GBS measurements presented. C1 SW Res Inst, San Antonio, TX 78238 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Blanchard, CR (reprint author), SW Res Inst, San Antonio, TX 78238 USA. NR 28 TC 3 Z9 3 U1 0 U2 0 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 JUN PY 1998 VL 81 IS 6 BP 1429 EP 1436 PG 8 WC Materials Science, Ceramics SC Materials Science GA ZV175 UT WOS:000074277600004 ER PT J AU Aldrich, DJ Jones, KM Govindarajan, S Moore, JJ Ohno, TR AF Aldrich, DJ Jones, KM Govindarajan, S Moore, JJ Ohno, TR TI Microstructure of molybdenum disilicide silicon carbide nanocomposite thin films SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID COMPOSITES; SILICIDES; MOSI2 AB Composite thin films of molybdenum disilicide-silicon carbide (MoSi2-SiC) have been deposited via rf magnetron sputtering onto molybdenum substrates. An intermediate layer was deposited in the presence of nitrogen gas and evaluated as a potential diffusion barrier layer. The composite films have been characterized using X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, and Auger electron spectroscopy. The as-deposited films were amorphous but crystallized into nanometer-sized grains after annealing under vacuum at 1000 degrees C for 30 min. There was a significant amount of interdiffusion between the film and substrate, which resulted in the formation of subsilicides such as Mo5Si3 and MoSi3, as well as Mo2C. The films that were deposited via reactive sputtering in a nitrogen ambient were amorphous in both the as-deposited and annealed conditions. Significantly fewer second phases were detected with the presence of the intermediate Layer, which suggests the potential use of the nitrided (MoSixNyCz) layer as a high-temperature diffusion barrier layer for the silicon and carbon. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. Colorado Sch Mines, Dept Met & Mat Engn, Golden, CO 80401 USA. Colorado Sch Mines, Dept Phys, Golden, CO 80401 USA. RP Caterpillar Inc, Adv Mat TEchnol, Peoria, IL 61656 USA. RI Ohno, Timothy/J-9384-2014 NR 23 TC 4 Z9 4 U1 2 U2 3 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0002-7820 EI 1551-2916 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD JUN PY 1998 VL 81 IS 6 BP 1471 EP 1476 PG 6 WC Materials Science, Ceramics SC Materials Science GA ZV175 UT WOS:000074277600009 ER PT J AU Rabin, BH Williamson, RL Bruck, HA Wang, XL Watkins, TR Feng, YZ Clarke, DR AF Rabin, BH Williamson, RL Bruck, HA Wang, XL Watkins, TR Feng, YZ Clarke, DR TI Residual strains in an Al2O3-Ni joint bonded with a composite interlayer: Experimental measurements and FEM analyses SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID CERAMIC-METAL INTERFACES; FINITE-ELEMENT ANALYSIS; STRESS DISTRIBUTION AB A cylindrical Al2O3-Ni joint bonded with a 4.0 mm thick composite interlayer of 40 vol% Al2O3-60 vol% Ni was fabricated by powder processing, and the residual strains in the specimen were studied experimentally using neutron diffraction, X-ray diffraction, and optical fluorescence spectroscopy. Experimental measurements were compared with finite element modeling results obtained using a variety of different constitutive assumptions. The predicted residual strain distribution within the Al2O3 along the center of the specimen was in reasonable agreement with neutron diffraction measurements, although the magnitude of the error in the experimental measurements did not allow a distinction to be made between the various modeling assumptions examined. In contrast, the predicted peak strains within the Al2O3 along the specimen surface were significantly higher than those measured by X-ray diffraction or optical fluorescence spectroscopy, suggesting that strain relief occurred near the free edge during cooling. The mechanism of strain relief is believed to involve damage accumulation within the composite interlayer that was not accounted for in the constitutive models used. C1 Idaho Natl Engn Lab, Idaho Falls, ID 83415 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. RP Rabin, BH (reprint author), Idaho Natl Engn Lab, Idaho Falls, ID 83415 USA. RI Wang, Xun-Li/C-9636-2010; Clarke, David/D-2616-2009; Albe, Karsten/F-1139-2011; Watkins, Thomas/D-8750-2016; OI Wang, Xun-Li/0000-0003-4060-8777; Watkins, Thomas/0000-0002-2646-1329; Williamson, Richard/0000-0001-7734-3632 NR 40 TC 34 Z9 35 U1 0 U2 4 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD JUN PY 1998 VL 81 IS 6 BP 1541 EP 1549 PG 9 WC Materials Science, Ceramics SC Materials Science GA ZV175 UT WOS:000074277600018 ER PT J AU Li, JB Xu, GY Sun, EY Huang, Y Becher, PF AF Li, JB Xu, GY Sun, EY Huang, Y Becher, PF TI Synthesis and morphology of niobium monocarbide whiskers SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article AB Niobium monocarbide (NbC) whiskers were successfully synthesized by heating mixtures of niobium oxide (Nb2O5) powder and carbon black in an argon atmosphere to temperatures in excess of 1100 degrees C. The whiskers were mainly cuboid or cycloid needles with a square-pyramid-shaped tip and were 0.1-2.0 mu m in width and 5-100 mu m in length. The particular shape of the whiskers and the very low impurity levels detected suggest that the NbC whiskers grew via a solid-vapor growth process. C1 Tsing Hua Univ, Dept Mat Sci & Engn, State Key Lab New Ceram & Fine Proc, Beijing 100084, Peoples R China. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Li, JB (reprint author), Tsing Hua Univ, Dept Mat Sci & Engn, State Key Lab New Ceram & Fine Proc, Beijing 100084, Peoples R China. NR 10 TC 23 Z9 25 U1 0 U2 1 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD JUN PY 1998 VL 81 IS 6 BP 1689 EP 1691 PG 3 WC Materials Science, Ceramics SC Materials Science GA ZV175 UT WOS:000074277600039 ER PT J AU Stephenson, JL McLuckey, SA AF Stephenson, JL McLuckey, SA TI Ion/ion reactions for oligopeptide mixture analysis: Application to mixtures comprised of 0.5-100 kDa components SO JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY LA English DT Article ID PROTON-TRANSFER REACTIONS; ELECTROSPRAY MASS-SPECTROMETRY; ION-MOLECULE REACTIONS; MULTIPLY-CHARGED IONS; GAS-PHASE; IONIZATION; DECONVOLUTION; ANIONS; PRINCIPLES; PROTEINS AB Oligopeptide mixtures have been subjected to electrospray ionization, accumulated within a quadrupole ion trap, and subjected to ion/ion proton transfer reactions with anions derived from perfluoro-1,3-dimethylcyclohexane. Various mixtures were studied with approximate molecular weight ranges of 0.5-8.5, 12-30, 45-100, and 0.5-100 kDa. Mixtures of known composition were studied to evaluate the mixture complexity amenable to electrospray combined with ion/ion reactions to reduce spectral complexity associated with multiple charging. Mixture analysis with at least 40 components of low and medium molecular weight and roughly comparable solution concentrations appears to be straightforward. No matrix effects upon ionization were implicated in the data for the low and medium molecular weight mixtures but bovine albumin appeared to inhibit signals from bovine transferrin and chicken conalbumin in the high molecular weight mix. Furthermore, the presence of abundant low mass-to-charge ions appeared to inhibit signals from high molecular weight proteins (>40 kDa) in the 0.5-100 kDa mix. Such an observation is consistent with dynamic range limitations that can arise from discrimination based on ion space charge effects, although an ionization matrix effect could not be precluded from the data reported here. The results reported here indicate that the limitation to mixture complexity amenable to electrospray mass spectrometry imposed by spectral congestion associated with multiple charging can be significantly reduced via ion/ion reactions. The use of ion/ion reactions can therefore facilitate the study of other factors that can impose limitations to mixture analysis, such as matrix effects upon ionization and differences in ion transmission, accumulation, storage, and detection efficiencies. (C) 1998 American Society for Mass Spectrometry. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP McLuckey, SA (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. EM mcluckey@ornl.gov RI Stephenson, James/A-9262-2009; McLuckey, Scott/B-2203-2009 OI McLuckey, Scott/0000-0002-1648-5570 NR 43 TC 52 Z9 52 U1 1 U2 6 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 JUN PY 1998 VL 9 IS 6 BP 585 EP 596 DI 10.1016/S1044-0305(98)00025-7 PG 12 WC Chemistry, Analytical; Chemistry, Physical; Spectroscopy SC Chemistry; Spectroscopy GA ZP262 UT WOS:000073734700004 PM 9879372 ER PT J AU Chong, SK Klubek, BP Weber, JT AF Chong, SK Klubek, BP Weber, JT TI Herbicide contamination by the 1993 Great Flood along the Mississippi River SO JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION LA English DT Article DE alachlor; atrazine; cyanazine ID ALACHLOR; ATRAZINE AB The Great Flood of 1993 inundated more than 355,000 ha of Illinois cropland, creating great concern for the possible contamination of farmland by herbicides. The objective of this study was to assess the herbicide contamination of floodwaters and farmland due to the great flood of 1993. Floodwater samples were collected between August 5 and December 20, 1993, at the Horseshoe Lake State Game Reserve in Alexander County, Illinois, USA. Water and suspended sediment were tested separately for the more commonly used herbicides in Illinois and the midwestern USA: alachlor, atrazine, and cyanazine. These herbicides were detected in the floodwater samples, but concentrations were all below the health advisory concentration of 3 mu g/L established for drinking water by the United States Environmental Protection Agency. No herbicides were detected in the suspended sediment. After the recession of the flood, soil samples from flooded and non-flooded corn fields were collected for comparison. Soil samples taken from two out of three sampling locations had a 0.4 to 0.8 mu g/kg increase in atrazine at the flooded verses the non-flooded sites. Concentrations were 500 to 1,000 times lower than the recommended 1 mg/kg rate at which this herbicides typically applied to soil. C1 So Illinois Univ, Plant Soil & Gen Agr Dept, Carbondale, IL 62901 USA. Univ Georgia, Savannah River Ecol Lab, Aiken, SC 29801 USA. RP Chong, SK (reprint author), So Illinois Univ, Plant Soil & Gen Agr Dept, Carbondale, IL 62901 USA. EM skchong@siu.edu NR 22 TC 10 Z9 11 U1 0 U2 6 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1093-474X J9 J AM WATER RESOUR AS JI J. Am. Water Resour. Assoc. PD JUN PY 1998 VL 34 IS 3 BP 687 EP 693 DI 10.1111/j.1752-1688.1998.tb00965.x PG 7 WC Engineering, Environmental; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA ZT244 UT WOS:000074065200020 ER PT J AU Qu, WQ Henderson-Sellers, A Pitman, AJ Chen, TH Abramopoulos, F Boone, A Chang, S Chen, F Dai, Y Dickinson, RE Dumenil, L Ek, M Gedney, N Gusev, YM Kim, J Koster, R Kowalczyk, EA Lean, J Lettenmaier, D Liang, X Mahfouf, JF Mengelkamp, HT Mitchell, K Nasonova, ON Noilhan, J Robock, A Rosenzweig, C Schaake, J Schlosser, CA Schulz, JP Shmakin, AB Verseghy, DL Wetzel, P Wood, EF Yang, ZL Zeng, Q AF Qu, WQ Henderson-Sellers, A Pitman, AJ Chen, TH Abramopoulos, F Boone, A Chang, S Chen, F Dai, Y Dickinson, RE Dumenil, L Ek, M Gedney, N Gusev, YM Kim, J Koster, R Kowalczyk, EA Lean, J Lettenmaier, D Liang, X Mahfouf, JF Mengelkamp, HT Mitchell, K Nasonova, ON Noilhan, J Robock, A Rosenzweig, C Schaake, J Schlosser, CA Schulz, JP Shmakin, AB Verseghy, DL Wetzel, P Wood, EF Yang, ZL Zeng, Q TI Sensitivity of latent heat flux from PILPS land-surface schemes to perturbations of surface air temperature SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID GENERAL-CIRCULATION MODELS; CLIMATE FEEDBACK PROCESSES; SOIL-MOISTURE; BOUNDARY-LAYER; PARAMETERIZATION; EVAPORATION; HYDROLOGY; BIOSPHERE; GCMS AB In the PILPS Phase 2a experiment, 23 land-surface schemes were compared in an off-line control experiment using observed meteorological data from Cabauw, the Netherlands. Two simple sensitivity experiments were also undertaken in which the observed surface air temperature was artificially increased or decreased by 2 K while all other factors remained as observed. On the annual timescale, all schemes show similar responses to these perturbations in latent, sensible heat flux, and other key variables. For the 2-K increase in temperature, surface temperatures and latent heat fluxes all increase while net radiation, sensible heat fluxes, and soil moistures all decrease. The results are reversed for a 2-K temperature decrease. The changes in sensible heat fluxes and, especially, the changes in the latent heat fluxes are nor linearly related to the change of temperature. Theoretically, the nonlinear relationship between air temperature and the latent heat flux is evident and due to the convex relationship between air temperature and saturation vapor pressure. A simple test shows that, the effect of the change of air temperature on the atmospheric stratification aside, this nonlinear relationship is shown in the form that the increase of the latent heat flux for a 2-K temperature increase is larger than its decrease for a 2-K temperature decrease. However, the results from the Cabauw sensitivity experiments show that the increase of the latent heat flux in the +2-K experiment is smaller than the decrease of the latent heat flux in the -2-K experiment (we refer to this as the asymmetry). The analysis in this paper shows that this inconsistency between the theoretical relationship and the Cabauw sensitivity experiments results (or the asymmetry) is due to (i) the involvement of the beta(g), formulation, which is a function of a series stress factors that limited the evaporation and whose values change in the +/-2-K experiments, leading to strong modifications of the latent heat flux; (ii) the change of the drag coefficient induced by the changes in stratification due to the imposed air temperature changes (+/-2 K) in parameterizations of latent heat flux common in current land-surface schemes. Among all stress factors involved in the beta(g), formulation, the soil moisture stress in the +2-K experiment induced by the increased evaporation is the main factor that contributes to the asymmetry. C1 RMIT Univ, Dept Math, Melbourne, Vic 3001, Australia. Macquarie Univ, Sch Earth Sci, Sydney, NSW 2109, Australia. Sci Syst & Applicat Inc, Sydney, NSW, Australia. NASA, Goddard Space Flight Ctr, Mesoscale Dynam & Precipitat Branch, Greenbelt, MD 20771 USA. Philips Labs, GPAB, PL, Hanscom AFB, MA USA. NOAA, Natl Ctr Environm Predict, Dev Div, Camp Springs, MD USA. Chinese Acad Sci, Inst Atmospher Phys, Beijing, Peoples R China. Univ Arizona, Inst Atmospher Phys, Tucson, AZ 85721 USA. Max Planck Inst Meteorol, Hamburg, Germany. Royal Netherlands Meteorol Inst, NL-3730 AE De Bilt, Netherlands. Univ Reading, Dept Meteorol, Reading, Berks, England. Russian Acad Sci, Inst Water Problems, Moscow, Russia. Lawrence Livermore Natl Lab, Livermore, CA USA. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. CSIRO, Div Atmospher Res, Aspendale, Vic 3195, Australia. Meteorol Off, Hadley Ctr Climate Predict & Res, Bracknell, Berks, England. Univ Washington, Dept Civil Engn, Seattle, WA 98195 USA. Princeton Univ, Dept Civil Engn & Operat Res, Princeton, NJ 08544 USA. ECMWF, Reading, Berks, England. GKSS, Res Ctr, Dept Phys, Geesthacht, Germany. Meteo France, CNRM, Toulouse, France. Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. NOAA, Natl Weather Serv, Off Hydrol, Silver Spring, MD 20910 USA. Russian Acad Sci, Inst Geog, Moscow, Russia. Atmospher Environm Serv, Climate Res Branch, Downsview, ON, Canada. Australian Oceanog Data Ctr, Sydney, NSW, Australia. RP Qu, WQ (reprint author), RMIT Univ, Dept Math, GPO Box 2476V, Melbourne, Vic 3001, Australia. EM rmawq@gauss.ma.rmit.edu.au RI Yang, Zong-Liang/B-4916-2011; Pitman, Andrew/A-7353-2011; Dai, Yongjiu/D-6261-2014; Henderson-Sellers, Ann/H-5323-2011; Koster, Randal/F-5881-2012; Chen, Fei/B-1747-2009; lettenmaier, dennis/F-8780-2011; Nasonova, Olga/B-6093-2014; gusev, yugeniy/G-4711-2014; Robock, Alan/B-6385-2016; OI Pitman, Andrew/0000-0003-0604-3274; Dai, Yongjiu/0000-0002-3588-6644; Koster, Randal/0000-0001-6418-6383; lettenmaier, dennis/0000-0003-3317-1327; gusev, yugeniy/0000-0003-3886-2143; Wood, Eric/0000-0001-7037-9675 NR 48 TC 32 Z9 36 U1 1 U2 9 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 EI 1520-0469 J9 J ATMOS SCI JI J. Atmos. Sci. PD JUN 1 PY 1998 VL 55 IS 11 BP 1909 EP 1927 DI 10.1175/1520-0469(1998)055<1909:SOLHFF>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZT491 UT WOS:000074093200001 ER PT J AU Pint, BA Alexander, KB AF Pint, BA Alexander, KB TI Grain boundary segregation of cation dopants in alpha-A(2)O(3) scales SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID HIGH-TEMPERATURE OXIDATION; FE-CR-AL; ALUMINA SCALES; REACTIVE ELEMENTS; GROWTH MECHANISMS; ION-IMPLANTATION; ODS ALLOY; BEHAVIOR; ZR; CR2O3 AB A Fe-20 atom % Cr-1O%Al matrix was dispersed with a wide range of oxide particulates in order to study the effect of oxygen-active dopants on high-temperature oxidation performance and alumina scale microstructure. The effects of these various cation dopants have been correlated with dopant ion segregation to the alpha-Al2O3 grain boundaries using analytical electron microscopy. Elements such as Mn and V showed little effect on the oxide scale microstructure and were not observed to segregate. Elements such as Y, Nd, and Gd were found to have a positive effect on oxidation performance and segregated to scale grain boundaries, resulting in finer, more columnar alpha-Al2O3 grains. However, Ti, Ta, Ca, and Nb also were found to segregate but had less of an effect on oxidation behavior. These results indicate that cation segregation to scale grain boundaries is not a sufficient condition for achieving beneficial oxidation performance. The driving force for diffusion and segregation in growing alumina scales is discussed. Based on comparisons with an alloy containing an Al2O3 dispersion, the finer scale grain sizes observed with reactive element oxide dispersions are the result of grain growth inhibition and not a heterogeneous nucleation effect. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Pint, BA (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Pint, Bruce/A-8435-2008 OI Pint, Bruce/0000-0002-9165-3335 NR 61 TC 65 Z9 67 U1 1 U2 20 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD JUN PY 1998 VL 145 IS 6 BP 1819 EP 1829 DI 10.1149/1.1838563 PG 11 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA ZN999 UT WOS:000073705200003 ER PT J AU Kolman, DG Gaudett, MA Scully, JR AF Kolman, DG Gaudett, MA Scully, JR TI Modeling of anodic current transients resulting from oxide rupture of plastically strained beta+alpha titanium SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID STRESS-CORROSION CRACKING; AQUEOUS CHLORIDE SOLUTIONS; SURFACE CURRENT DENSITIES; 304L STAINLESS-STEEL; SCRATCHED ELECTRODE; FILM GROWTH; REPASSIVATION; BETA; BEHAVIOR; KINETICS AB The film rupture behavior on dynamically strained Ti-15 Mo-3 Nb-3 Al exposed to 0.6 M NaCl has been examined by rapid data acquistion of anodic current transients. The anodic current transients resulted from dislocation intersection of the passive film, followed by film rupture, bare surface dissolution, and repassivation. The transient morphology during dynamic straining differs from that generated via conventional depassivation techniques (i.e., manual scratch and fractured thin film depassivation) which incorporate an electrode that does not experience active plastic straining following depassivation. During conventional depassivation testing, current transients increase relatively rapidly and decay with an approximately linear slope on the log i-log t plot. In contrast, the transients acquired during dynamic straining are characterized by a relatively slow current increase and a nonlinear current decay on the log i-log t plot. This nonlinear decay is not attributable to ohmic or capacitive effects. The difference between the anodic transient morphologies on dynamically strained and unstrained electrodes is attributed to the combination of many discrete dislocation intersections of the surface over a period which is much larger than the time required for repassivation of a single dislocation intersection. Additionally, atomic force microscopy revealed persistent slip on a limited number of slip planes, with slip offsets as large as 600 nm, which is consistent with the formation and emergence of superdislocations. Thus, film rupture results from sc-face intersection of a superdislocation comprised of individual dislocations which are spatially and temporally separated. Current transient modeling of superdislocation intersection agrees qualitatively with that observed experimentally. It is concluded that the repassivation behavior determined by conventional depassivation techniques may not be relevant for modeling of environmentally assisted cracking of dynamically strained electrodes in some cases. C1 Univ Calif Los Alamos Natl Lab, Mat Corros & Environm Effects Lab, Los Alamos, NM 87545 USA. USN, Ctr Surface Warfare, Carderock Div, W Bethesda, MD 20817 USA. Univ Virginia, Dept Mat Sci & Engn, Ctr Electrochem Sci & Engn, Charlottesville, VA 22903 USA. RP Kolman, DG (reprint author), Univ Calif Los Alamos Natl Lab, Mat Corros & Environm Effects Lab, POB 1663, Los Alamos, NM 87545 USA. RI Street, Steven/A-5398-2015 OI Street, Steven/0000-0002-8999-3701 NR 72 TC 22 Z9 22 U1 0 U2 6 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD JUN PY 1998 VL 145 IS 6 BP 1829 EP 1840 DI 10.1149/1.1838564 PG 12 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA ZN999 UT WOS:000073705200004 ER PT J AU Zhang, JG Liu, P Turner, JA Tracy, CE Benson, DK AF Zhang, JG Liu, P Turner, JA Tracy, CE Benson, DK TI Highly stable vanadium oxide cathodes prepared by plasma-enhanced chemical vapor deposition SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID THIN-FILMS; VO2 FILMS; BATTERIES; LITHIUM; ELECTRODES AB Vanadium oxide films have been prepared by plasma-enhanced chemical vapor deposition for rechargeable Lithium-battery applications. Vanadium oxytrichloride (VOCl3) was employed as the vanadium precursor. Various parameters, such as the partial pressures of carrier gas and reactant gases, substrate temperature, and radio-frequency power, have been optimized to improve the electrochemical properties of the films. The film deposition rate was similar to 11 Angstrom/s. The best films obtained in this work displayed an oxygen-to-vanadium atomic ratio close to that of V6O13. These films exhibited a high discharge capacity and were very stable during electrochemical cycling. The discharge capacity of these films exceeded 408 mAh/g (or 1265 mAh/cm(3)) when tested between 4.0 and 1.5 V, and the energy density of these films (similar to 5000 Angstrom thick) was 960.3 Wh/kg. The films exhibited negligible capacity fade from the second cycle to more than 5800 cycles when cycled between 4.0 ana 1.8 V with a current density of 114 mu Angstrom/cm(2). The combination of high capacity, extended cycling stability and rapid deposition rate make both this material and its deposition technology very attractive choices for the manufacturers of rechargeable lithium batteries. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Zhang, JG (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Liu, Ping/I-5615-2012 NR 21 TC 25 Z9 25 U1 0 U2 2 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD JUN PY 1998 VL 145 IS 6 BP 1889 EP 1892 DI 10.1149/1.1838572 PG 4 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA ZN999 UT WOS:000073705200012 ER PT J AU Oblonsky, LJ Ryan, MP Isaacs, HS AF Oblonsky, LJ Ryan, MP Isaacs, HS TI In situ determination of the composition of surface films formed on Fe-Cr alloys SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID IRON-CHROMIUM ALLOYS; X-RAY-ABSORPTION; PASSIVE FILMS; PERCOLATION MODEL; STAINLESS-STEELS; IN-SITU; FE/CR ALLOYS; OXIDE FILM; XANES; SPECTROSCOPY AB A method for using in situ X-ray absorption near edge spectroscopy to determine the composition of passive, transpassive, and nonreducible thin oxide films is described. The method is demonstrated by determining the composition of the passive films formed in pH 4.5, 0.1 M acetate buffer, on 100 Angstrom thick Fe-yCr alloys (y = 8.5, 15, 19, 23 atom %) at potentials: (i) low in the passive region (-0.3 V vs. mercurous sulfate reference electrode, MSE); (ii) high in the passive region (+0.2 V MSE); (iii) in the transpassive region (+0.8 V MSE); and (iv) in the cathodic region where the air-formed film is not fully reduced (e.g., -1.2 V MSE). The nonreducible film at -1.2 V is entirely a Cr3+ oxide/hydroxide, due to reductive dissolution at -1.2 V of all the Fe that was present in the air-formed film. This nonreducible film persists at anodic potentials. At -0.3 V, the passive film on each alloy is significantly enriched in Cr, present as Cr3+. Fe, if present, exists as both Fe2+ and Fe3+. The film at -0.3 V consists primarily of the nonreducible Cr3+ oxide/hydroxide plus a very small amount of additional oxidized alloy; at this potential most Fe dissolves as Fe2+. At +0.2 V, Fe is present in the passive film only as Fe3+, Cr as Cr3+, and the passive film is less enriched in Cr than at -0.3 V. The composition of the transpassive film at +0.8 V is nearly the same as the composition of the film at +0.2 V,with Fe present at Fe3+, but Cr is present as both Cr3+ and a small amount of Cr6+ (10-25% of the total Cr in the oxide). At +0.2 and +0.8 V, the passive film consists of the nonreducible Cr3+ oxide/hydroxide plus significant amounts of additional oxidized alloy. Formation of the +0.2 and +0.8 V films proceeds with little dissolution of Fe or Cr. C1 Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. RP Oblonsky, LJ (reprint author), Dupont Co, Cent Res & Dev, Expt Stn, Wilmington, DE 19880 USA. NR 30 TC 55 Z9 57 U1 3 U2 12 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD JUN PY 1998 VL 145 IS 6 BP 1922 EP 1932 DI 10.1149/1.1838577 PG 11 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA ZN999 UT WOS:000073705200017 ER PT J AU Lillard, RS Scully, JR AF Lillard, RS Scully, JR TI Electrochemical passivation of ordered NiAl SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID RAY PHOTOELECTRON-SPECTROSCOPY; GRAIN-BOUNDARY FRACTURE; ENVIRONMENTAL EMBRITTLEMENT; INITIAL-STAGES; NI3AL ALLOY; OXIDATION; NICKEL; MECHANISM; CORROSION; ALUMINUM AB The passivity and electrochemical behavior of single crystalline, ordered NiAl intermetallic compound in buffered solutions of pH 2, 7, and 12.5 was compared to that of polycrystalline Ni and Al. NiAl exhibited improved passivity compared to Ni at a pH of 2, and improved passivity compared to Al at pH 12.5. Water oxidation and reduction were enhanced on NiAl compared to Al, suggesting the presence of a more conductive or catalytic oxide film. Al2O3 was preferentially formed (> 60 atom % of all oxidized Ni and Al species) throughout the interior of oxide films formed anodically at each pH as well as within the air-formed oxide grown at room temperature. However, the oxide surface layers exhibited a tendency toward nearly equal presence of oxidized Ni+2, especially as the pH was increased to 7 and 12.5. Therefore, Al2O3 formation was favored, but not exclusively, during electrochemical passivation. In contrast, little or no Ni+2 las NiO or NiAl2O4) has been reported after high temperature oxidation of NiAl. The composition of the electrochemically grown oxide is influenced by the specific oxide solubility and kinetic formation/dissolution rates at the oxide/solution interface as well. as by the free energy of formation of the oxides. C1 Univ Virginia, Dept Mat Sci & Engn, Ctr Electrochem Sci & Engn, Charlottesville, VA 22903 USA. RP Lillard, RS (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 35 TC 6 Z9 6 U1 1 U2 2 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD JUN PY 1998 VL 145 IS 6 BP 2024 EP 2032 DI 10.1149/1.1838593 PG 9 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA ZN999 UT WOS:000073705200033 ER PT J AU Sun, J Bartholomew, RF Bellur, K Srivastava, A Osburn, CM Masnari, NA Westhoff, R AF Sun, J Bartholomew, RF Bellur, K Srivastava, A Osburn, CM Masnari, NA Westhoff, R TI Parasitic resistance considerations of using elevated source/drain technology for deep submicron metal oxide semiconductor field effect transistors SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID NMOSFETS; MOSFET AB Device drive current, parasitic resistance, and junction leakage current have been studied using silicided and non-silicided deep submicron elevated source/drain (ESD) n-channel metal oxide semiconductor field effect transistors (NMOSFETs). This study illustrated the effects of doping profile in the elevated S/D region, junction depth in the substrate, and doping level in the source/drain extension. Compared to devices having nonelevated junctions with the same substrate doping profile, MOSFETs with a profile-doped elevated S/D, used to contact an ultrashallow junction formed before selective epitaxial growth, had higher drive currents and demonstrated the ability of the elevated junction to reduce the extrinsic resistance. Measurements of drive currents in ESD devices showed that (i) the lightly doped region at the bottom of a profile-doped elevated layer introduces additional extrinsic resistance, and (ii) the locally deeper junction beneath the epi facets extends laterally toward the channel and shortens the drain extension length, thereby reducing the intrinsic resistance. Silicided devices had higher drive current and reduced parasitic resistance when the silicide/silicon interfacial dopant concentrations remained high (> 1 x 10(20)/cm(3)) after silicidation. The lowest total parasitic resistance was achieved when the elevated S/D was used to give a small contact resistance to a shallow junction and a moderately doped drain extension was used to lower the resistance of the source/drain extension tab. C1 N Carolina State Univ, Dept Elect & Comp Engn, Raleigh, NC 27695 USA. Lawrence Semicond Res Lab, Tempe, AZ 85282 USA. RP Adv Micro Devices Inc, Sunnyvale, CA 94088 USA. NR 19 TC 5 Z9 5 U1 0 U2 2 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 JUN PY 1998 VL 145 IS 6 BP 2131 EP 2137 DI 10.1149/1.1838607 PG 7 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA ZN999 UT WOS:000073705200047 ER PT J AU Teyssandier, F Allendorf, MD AF Teyssandier, F Allendorf, MD TI Thermodynamics and kinetics of gas-phase reactions in the Ti-Cl-H system SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID CHEMICAL-VAPOR-DEPOSITION; TITANIUM NITRIDE; TEMPERATURE-DEPENDENCE; THERMOCHEMISTRY; SUBSTRATE; DIBORIDE; PRESSURE; LPCVD AB A mechanism and associated rate constants for the gas-phase chemical reactions that occur during the chemical vapor deposition (CVD) of titanium from titanium tetrachloride (TiCl4)/hydrogen mixtures is presented. TiCl4 is the most widely used inorganic precursor employed in the CVD of titanium-containing materials, such as titanium nitride, titanium carbide, and titanium diboride. Although the thermodynamic properties of this compound and its subchlorides TiCl4 (n = 2-4) are fairly well known, their gas-phase decomposition kinetics have not been characterized. In this work, rate constants for the unimolecular decomposition reactions of the titanium chlorides were predicted using Rice-Ramsberger-Kassel-Marcus theory for unimolecular reaction, while the rate constants for bimolecular reactions between TiCl4 species and hydrogen atoms were estimated using an empirical correlation. Calculations at thermodynamic equilibrium over a range of temperatures and total pressures characteristic of Ti CVD conditions are presented first. The time-dependent evolution of the gas-phase composition is then simulated using the proposed mechanism. The results show that at 1500 K complete equilibrium is reached in approximately 2 s at any total pressure in the range 0.01-101 kPa (1-760 Torr). The approach to equilibrium is much slower at 1000 K, with more than 300 s required to reach equilibrium at 101 kPa. Due to the pressure dependence of the unimolecular reactions in the mechanism these times are significantly shorter at atmospheric pressure than at reduced pressures. The results suggest that equilibrium predictions of gas-phase concentrations should be a good approximation at 1500 K, unless very short residence times and low pressures are involved. In contrast, equilibrium calculations do not accurately reflect the gas-phase composition at 1000 K. C1 Univ Perpignan, Inst Sci & Genie Mat & Procedes, CNRS, UPR8521, F-66860 Perpignan, France. Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. RP Teyssandier, F (reprint author), Univ Perpignan, Inst Sci & Genie Mat & Procedes, CNRS, UPR8521, F-66860 Perpignan, France. NR 53 TC 16 Z9 16 U1 2 U2 6 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD JUN PY 1998 VL 145 IS 6 BP 2167 EP 2178 DI 10.1149/1.1838613 PG 12 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA ZN999 UT WOS:000073705200053 ER PT J AU Rubenstein, F AF Rubenstein, F TI Investigation of light distribution with an annular lens light guide - Discussion SO JOURNAL OF THE ILLUMINATING ENGINEERING SOCIETY LA English DT Editorial Material C1 Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Rubenstein, F (reprint author), Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ILLUMINAT ENG SOC NORTH AMER PI NEW YORK PA 120 WALL ST, 17TH FL, NEW YORK, NY 10005-4001 USA SN 0099-4480 J9 J ILLUM ENG SOC JI J. Illum. Eng. Soc. PD SUM PY 1998 VL 27 IS 2 BP 10 EP 11 PG 2 WC Optics SC Optics GA 108FW UT WOS:000075256300002 ER PT J AU Siminovitch, M AF Siminovitch, M TI Method for estimating the efficiency of prism light guide luminaires - Discussion SO JOURNAL OF THE ILLUMINATING ENGINEERING SOCIETY LA English DT Editorial Material C1 Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Siminovitch, M (reprint author), Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ILLUMINAT ENG SOC NORTH AMER PI NEW YORK PA 120 WALL ST, 17TH FL, NEW YORK, NY 10005-4001 USA SN 0099-4480 J9 J ILLUM ENG SOC JI J. Illum. Eng. Soc. PD SUM PY 1998 VL 27 IS 2 BP 19 EP 19 PG 1 WC Optics SC Optics GA 108FW UT WOS:000075256300009 ER PT J AU Page, E Siminovitch, M Marr, L Mitchell, J AF Page, E Siminovitch, M Marr, L Mitchell, J TI Energy efficient alternatives to halogen torchieres SO JOURNAL OF THE ILLUMINATING ENGINEERING SOCIETY LA English DT Article AB A series of novel energy efficient torchiere systems have been developed using compact fluorescent lamps (CFLs). These systems were studied photometrically and compared with the performance of traditional commercially available tungsten halogen sources. Gonio-photometric data and power assessments indicate that significant lighting energy savings can be obtained by utilizing Cm, sources instead of standard tungsten halogen sources. This energy savings is jointly due to the higher source efficacy of the CFLs and the surprisingly poor performance of the imported 300 W halogen lamps. Experimental data shows that a 50 to 60 W cm, will effectively lumen match a variety of 300 W tungsten halogen sources with five to ten times the efficacy. Cm, torchieres have additional benefits of higher power quality and cooler lamp operating temperature, making them safer fixtures. C1 Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Page, E (reprint author), Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RI Marr, Linsey/C-9698-2010 OI Marr, Linsey/0000-0003-3628-6891 NR 4 TC 0 Z9 0 U1 0 U2 0 PU ILLUMINAT ENG SOC NORTH AMER PI NEW YORK PA 120 WALL ST, 17TH FL, NEW YORK, NY 10005-4001 USA SN 0099-4480 J9 J ILLUM ENG SOC JI J. Illum. Eng. Soc. PD SUM PY 1998 VL 27 IS 2 BP 28 EP + PG 6 WC Optics SC Optics GA 108FW UT WOS:000075256300018 ER PT J AU Ehrlich, C AF Ehrlich, C TI Simulating the visual performance of electrochromic glazing for solar control SO JOURNAL OF THE ILLUMINATING ENGINEERING SOCIETY LA English DT Article AB The development of new building products typically involves long delays before marketability. The products may be based on scientifically sound technologies but may lack full-size working prototypes with which to evaluate or demonstrate their physical performance. Lawrence Berkeley National Laboratory's Advanced Materials Research Group is developing electrochromic glazing which promises to fill a need for building solar control. which is both dynamic and integral to the building envelope. Electrochromic devices have been produced in sizes up to 1 ft(2); however, all of the manufacturers are several years away from being able to produce glazing samples large enough to fill the entire aperture of a typical perimeter office. Tooling up for the production of large samples is prohibitively expensive unless some assurance of the marketability of the product can be demonstrated. Participants in the development of electrochromic glazings all have questions about the performance of their future products. This paper describes a simulation method which allows the user to answer the following questions: What rate of coloration and bleaching is fast enough to control solar exposure to the satisfaction of occupants? Can the coloration and bleaching rates be switched too quickly! Will users accept the blue tint of some of these devices? The paper discusses the rendering techniques and underlying technologies used in the animated simulation. C1 Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Ehrlich, C (reprint author), Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU ILLUMINAT ENG SOC NORTH AMER PI NEW YORK PA 120 WALL ST, 17TH FL, NEW YORK, NY 10005-4001 USA SN 0099-4480 J9 J ILLUM ENG SOC JI J. Illum. Eng. Soc. PD SUM PY 1998 VL 27 IS 2 BP 141 EP + PG 9 WC Optics SC Optics GA 108FW UT WOS:000075256300071 ER PT J AU Triantafyllidis, N Schraad, MW AF Triantafyllidis, N Schraad, MW TI Onset of failure in aluminum honeycombs under general in-plane loading SO JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS LA English DT Article DE buckling; microstructures; elastic-plastic material; finite deflections; foam material ID CELLULAR MATERIALS; MECHANICAL-PROPERTIES; MULTIAXIAL LOADS; COMPOSITES; SURFACES; SOLIDS; MODELS AB Of interest here is the theoretical prediction of the onset of failure in aluminum honeycombs under arbitrary macroscopic loading conditions. A failure surface is defined in macroscopic stress space by the onset of the first buckling-type instability encountered along proportional load paths, where each load path is defined by a fixed macroscopic load orientation and a fixed ratio of principal macroscopic stresses. The influence of specimen size (i.e., geometric scale effects), and the influence of geometric microstructural imperfections on these failure surfaces, are investigated through a combination of analytical (i.e., Bloch wave) and numerical (i.e., finite element) techniques. All of the analyses presented here are carried out for commercially available honeycombs, and the results show an extreme sensitivity of the onset of failure in these materials to the macroscopic load orientation and the principal macroscopic stress ratio. In addition, the failure surface for a perfectly periodic honeycomb of infinite extent. is found to be an upper bound for the failure surfaces of the corresponding finite honeycomb specimens with microstructural imperfections. Moreover, the construction of the failure surfaces for the imperfect specimens requires the numerical solution for large, multicell models, while the failure surface for the finite, perfectly periodic model is obtained with less computational effort, since calculations involving only the unit cell are required. The methodology proposed in this investigation, therefore, provides a useful predictive tool for the design of these materials. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Univ Michigan, Dept Aerosp Engn, Ann Arbor, MI 48109 USA. RP Triantafyllidis, N (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Grp T-3,Mail Stop B216, Los Alamos, NM 87545 USA. NR 22 TC 95 Z9 96 U1 3 U2 16 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-5096 J9 J MECH PHYS SOLIDS JI J. Mech. Phys. Solids PD JUN PY 1998 VL 46 IS 6 BP 1089 EP 1124 DI 10.1016/S0022-5096(97)00060-4 PG 36 WC Materials Science, Multidisciplinary; Mechanics; Physics, Condensed Matter SC Materials Science; Mechanics; Physics GA ZP055 UT WOS:000073712000005 ER PT J AU Dykhuizen, RC Smith, MF AF Dykhuizen, RC Smith, MF TI Gas dynamic principles of cold spray SO JOURNAL OF THERMAL SPRAY TECHNOLOGY LA English DT Article DE analytic; coating; cold spray; gas dynamic AB This paper presents an analytical model of the cold-spray process, By assuming a one-dimensional isentropic flow and constant gas properties, analytical equations are solved to predict the spray particle velocities. The solutions demonstrate the interaction between the numerous geometric and material properties. The analytical results allow determination of an optimal design for a cold-spray nozzle, The spray particle velocity is determined to be a strong function of the gas properties, particle material density, and size, It is also shown that the system performance is sensitive to the nozzle length, but not sensitive to the nozzle shape. Thus, it is often possible to use one nozzle design for a variety of operational conditions. Many of the results obtained in this article are also directly applicable to other thermal spray processes. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Dykhuizen, RC (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 11 TC 268 Z9 285 U1 6 U2 66 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 1059-9630 J9 J THERM SPRAY TECHN JI J. Therm. Spray Technol. PD JUN PY 1998 VL 7 IS 2 BP 205 EP 212 DI 10.1361/105996398770350945 PG 8 WC Materials Science, Coatings & Films SC Materials Science GA ZZ741 UT WOS:000074762500032 ER PT J AU Kanouff, MP Neiser, RA Roemer, TJ AF Kanouff, MP Neiser, RA Roemer, TJ TI Surface roughness of thermal spray coatings made with off-normal spray angles SO JOURNAL OF THERMAL SPRAY TECHNOLOGY LA English DT Article DE coating; coating formation simulation; high velocity oxygen fuel (HVOF); modeling; off-normal spray angle; over-spray; surface roughness; thermal spray ID SOLIDIFICATION; DROPLETS; MODEL AB The formation of a thermal spray coating using an off-normal direction angle for the spray has been analyzed to identify the causes of the large surface roughness of the coating. In the analysis, the string method was used for modeling the formation of the coating. The method uses a string of equally spaced node points to define the shape of the coating surface and to track the change in this shape as the thermal spray mass is deposited. The method allows for the calculation of arbitrary shapes for the coating surface that may be very complex. The model simulates the stochastic deposition of a large number of thermal spray droplets, Experiments were carried out to obtain the data used in the model for the mass flux distribution on the target surface. The data show that when the thermal spray mass impinges on the target surface a large fraction of it, called overspray, splashes off the target and is redeposited with a small direction angle. This component of the deposited mass results in a large coating roughness. C1 Sandia Natl Labs, Mech & Simulat Mfg Proc Dept, Livermore, CA 94550 USA. Sandia Natl Labs, Direct Fabricat Dept, Albuquerque, NM 87185 USA. RP Kanouff, MP (reprint author), Sandia Natl Labs, Mech & Simulat Mfg Proc Dept, Livermore, CA 94550 USA. NR 20 TC 32 Z9 34 U1 1 U2 6 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 1059-9630 J9 J THERM SPRAY TECHN JI J. Therm. Spray Technol. PD JUN PY 1998 VL 7 IS 2 BP 219 EP 228 DI 10.1361/105996398770350963 PG 10 WC Materials Science, Coatings & Films SC Materials Science GA ZZ741 UT WOS:000074762500034 ER PT J AU van't Wout, AB Blaak, H Ran, LJ Brouwer, M Kuiken, C Schuitemaker, H AF van't Wout, AB Blaak, H Ran, LJ Brouwer, M Kuiken, C Schuitemaker, H TI Evolution of syncytium-inducing and non-syncytium-inducing biological virus clones in relation to replication kinetics during the course of human immunodeficiency virus type 1 infection SO JOURNAL OF VIROLOGY LA English DT Article ID T-CELL-LINE; PRIMARY HIV-1 ISOLATE; REVERSE-TRANSCRIPTASE; VIRAL PHENOTYPE; GENE; DOMAIN; PROGRESSION; MACROPHAGE; RECEPTOR; VARIANTS AB To investigate the temporal relationship between human immunodeficiency virus type 1 (HIV-1) replicative capacity and syncytium-inducing (SI) phenotype, biological and genetic characteristics of longitudinally obtained virus clones from two HIV-1-infected individuals who developed SI variants were studied. In one individual, the emergence of rapidly replicating SI and non-syncytium-inducing (NSI) variants was accompanied by a loss of the slowly replicating NSI variants. In the other subject, NSI variants were always slowly replicating, while the coexisting SI variants showed an increase in the rate of replication. Irrespective their replicative capacity, the NSI variants remained present throughout the infection in both individuals. Phylogenetic analysis of the V3 region showed early branching of the SI variants from the NSI tree. Successful SI conversion seemed a unique event since no SI variants were found among later-stage NSI variants. This was also confirmed by the increasing evolutionary distance between the two subpopulations. At any time point during the course of the infection, the variation within the coexisting SI and NSI populations did not exceed 2%, indicating continuous competition within each viral subpopulation. C1 Netherlands Red Cross, Blood Transfus Serv, Cent Lab, Dept Clin Viroimmunol, NL-1066 CX Amsterdam, Netherlands. Univ Amsterdam, Acad Med Ctr, Expt & Clin Immunol Lab, NL-1105 AZ Amsterdam, Netherlands. Univ Calif Los Alamos Natl Lab, HIV Database & Anal Grp, Los Alamos, NM USA. RP Schuitemaker, H (reprint author), Netherlands Red Cross, Blood Transfus Serv, Cent Lab, Dept Clin Viroimmunol, Plesmanlaan 125, NL-1066 CX Amsterdam, Netherlands. EM J_Schuitemaker@CLB.nl NR 62 TC 82 Z9 82 U1 0 U2 3 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 USA SN 0022-538X J9 J VIROL JI J. Virol. PD JUN PY 1998 VL 72 IS 6 BP 5099 EP 5107 PG 9 WC Virology SC Virology GA ZM029 UT WOS:000073497600065 PM 9573281 ER PT J AU Eastman, PS Mittler, J Kelso, R Gee, C Boyer, E Kolberg, J Urdea, M Leonard, JM Norbeck, DW Mo, HM Markowitz, M AF Eastman, PS Mittler, J Kelso, R Gee, C Boyer, E Kolberg, J Urdea, M Leonard, JM Norbeck, DW Mo, HM Markowitz, M TI Genotypic changes in human immunodeficiency virus type 1 associated with loss of suppression of plasma viral RNA levels in subjects treated with ritonavir (norvir) monotherapy SO JOURNAL OF VIROLOGY LA English DT Article ID HIV-1 REVERSE-TRANSCRIPTASE; DYNAMICS IN-VIVO; PROTEASE INHIBITOR; ZIDOVUDINE RESISTANCE; REDUCED SENSITIVITY; PROTEINASE-INHIBITOR; INVITRO SELECTION; SHORT-TERM; MUTATIONS; VARIANTS AB Ten subjects received 600 to 1,200 mg of the human immunodeficiency virus type 1 (HIV-1) protease inhibitor ritonavir per day, Following 2 weeks of therapy, plasma HIV RNA levels decreased by a mean of 1.57 (range, 0.89 to 1.96) log units, With continued therapy, HIV RNA levels began to rise in eight subjects. The initial rise in plasma RNA levels was temporally associated with the development and quantitative increase in the V82 resistance mutation. Doubling times of the V82A mutant virus were estimated to be 2.4 to 4.8 days. An L63P/A mutation was commonly present at baseline even in subjects with a durable virologic response. The concomitant acquisition of an L63P/A mutation with the V82A/F mutation at the time when plasma RNA levels rebounded suggests a role for the L63P/A mutation in improving the fitness of the V82A/F mutation. Subsequent additional genotypic changes at codons 54 and 84 were often associated with further increases in plasma RNA levels. Ongoing viral replication in the presence of drugs resulted in the appearance of additional genotypic changes, including the L90M saquinavir resistance mutation, and decreased phenotypic susceptibility. The relative fitness of the protease V82A ritonavir resistance mutation and reverse transcriptase T215Y/F zidovudine resistance mutation following drug withdrawal were estimated to be 96 to 98% that of the wild type. Durability of the virologic response was associated with plasma RNA levels at the nadir. A virologic response beyond 60 days was not observed unless plasma HIV RNA levels were suppressed below 2,000 copies/ml, consistent with estimates from V82A doubling times for selection of a single resistance mutation to dominate the replicating population. C1 Chiron Corp, Emeryville, CA 94608 USA. Univ Calif Los Alamos Natl Lab, Theoret Biol & Biophys, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. Abbott Labs, Div Pharmaceut Prod, Abbott Pk, IL 60064 USA. Abbott Labs, Antiinfect Res, Abbott Pk, IL 60064 USA. NYU, Sch Med, Aaron Diamond AIDS Res Ctr, New York, NY 10016 USA. RP Eastman, PS (reprint author), Chiron Corp, 4560 Horton St, Emeryville, CA 94608 USA. NR 49 TC 67 Z9 68 U1 0 U2 0 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 USA SN 0022-538X J9 J VIROL JI J. Virol. PD JUN PY 1998 VL 72 IS 6 BP 5154 EP 5164 PG 11 WC Virology SC Virology GA ZM029 UT WOS:000073497600071 PM 9573287 ER PT J AU Streitwieser, A Xie, LF Speers, P Williams, PG AF Streitwieser, A Xie, LF Speers, P Williams, PG TI Kinetic acidities of some hydrocarbons by tritium NMR SO MAGNETIC RESONANCE IN CHEMISTRY LA English DT Article DE NMR; H-3 NMR; exchange rates; cesium cyclohexylamide; kinetic acidity; hydrocarbon AB Exchange rates in cyclohexylamine-N-H-3 catalyzed by cesium cyclohexylamide were determined by H-3 NMR for the vinyl positions of 3,3-dimethyl-1-butene (1-trans > l-cis > 2-) and the cyclopropyl methylene positions of norcarane (exo > endo) relative to the ring position of p-xylene. The kinetic acidity of cubane was confirmed. (C) 1998 John Wiley & Sons, Ltd. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Natl Tritium Labelling Facil, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA. RP Streitwieser, A (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 10 TC 5 Z9 5 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0749-1581 J9 MAGN RESON CHEM JI Magn. Reson. Chem. PD JUN PY 1998 VL 36 SI SI BP S209 EP S211 DI 10.1002/(SICI)1097-458X(199806)36:133.3.CO;2-O PG 3 WC Chemistry, Multidisciplinary; Chemistry, Physical; Spectroscopy SC Chemistry; Spectroscopy GA ZY964 UT WOS:000074681200028 ER PT J AU Alwazzan, M Hamshere, MG Lennon, GG Brook, JD AF Alwazzan, M Hamshere, MG Lennon, GG Brook, JD TI Six transcripts map within 200 kilobases of the myotonic dystrophy expanded repeat SO MAMMALIAN GENOME LA English DT Article ID EXON AMPLIFICATION; CTG REPEAT; GENE; PROTEIN; LOCUS C1 Univ Nottingham, Queens Med Ctr, Dept Genet, Nottingham NG7 2UH, England. Univ Nottingham, City Hosp NHS Trust, Ctr Med Genet, Nottingham NG6 1PB, England. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Brook, JD (reprint author), Univ Nottingham, Queens Med Ctr, Dept Genet, Nottingham NG7 2UH, England. OI Brook, John David/0000-0002-5946-6740 NR 21 TC 6 Z9 7 U1 0 U2 2 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 JUN PY 1998 VL 9 IS 6 BP 485 EP 487 DI 10.1007/s003359900804 PG 3 WC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity GA ZN865 UT WOS:000073691200017 PM 9585442 ER PT J AU Cooper, LW Beasley, TM Zhao, XL Soto, C Vinogradova, KL Dunton, KH AF Cooper, LW Beasley, TM Zhao, XL Soto, C Vinogradova, KL Dunton, KH TI Iodine-129 and plutonium isotopes in Arctic kelp as historical indicators of transport of nuclear fuel-reprocessing wastes from mid-to-high latitudes in the Atlantic Ocean SO MARINE BIOLOGY LA English DT Article ID MASS-SPECTROMETRY; LAMINARIA-SOLIDUNGULA; I-129; ENVIRONMENT; GROWTH; TRACER; STRAIT; WATER AB Iodine-129:iodine-127 ratios were determined using accelerator mass spectrometry in 34 Arctic marine algae collected between 1930 and 1993, A smaller set (5) of marine algae were also analyzed mass spectrometrically to determine plutonium-isotope ratios. The I-129:I-127 ratio increased as much as three orders of magnitude from a mean of < 1 x 10(-11) (atom/atom) in the pre-nuclear era (before 1945) to nearly 1000 x 10(-11) in 1993 for marine algae collected from the Novaya Zemlya archipelago separating the Barents and Kara Seas. The predominant basis for the higher ratios in the Novaya Zemlya kelps appears to be upcurrent sources of I-129 from nuclear fuel-reprocessing facilities at Sellafield (UK) and La Hague (France). Relatively high Pu-241:Pu-239 ratios (compared to observed bomb fallout at boreal latitudes, decay corrected to the date of collection) also corroborate the influence of non-fallout sources. The small size of the data set precludes determining if there are significant contributions of I-129 and other radionuclides from Russian sources. In contrast. marine algae collected between 1969 and 1993 in the Bering, Beaufort and East Siberian Seas had much lower I-129:I-127 ratios (mean = 14.04 x 10(-11) +/- 3.15 SD) than those observed in the European Arctic. The narrow range of ratios in Ameriasian Arctic kelps, and the modest change over that time period, indicate that there were ilo major contributions of non-fallout I-129 to North American Arctic surface waters at the time that the al ae were collected. The potential for timing the transport of fuel-reprocessed I-129 through analysis of additional archived samples is outlined. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. US Dept Energy, New York, NY 10014 USA. Univ Toronto, Isotrace Lab, Toronto, ON M5S 1A7, Canada. VL Komarov Bot Inst, St Petersburg 197376, Russia. Univ Texas, Inst Marine Sci, Port Aransas, TX 78373 USA. RP Cooper, LW (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008,MS 6038, Oak Ridge, TN 37831 USA. RI Cooper, Lee/E-5251-2012 OI Cooper, Lee/0000-0001-7734-8388 NR 31 TC 33 Z9 33 U1 0 U2 13 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0025-3162 J9 MAR BIOL JI Mar. Biol. PD JUN PY 1998 VL 131 IS 3 BP 391 EP 399 DI 10.1007/s002270050332 PG 9 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 110JY UT WOS:000075378700001 ER PT J AU Ma, B Balachandran, U Hodges, JP Jorgensen, JD Miller, DJ Richardson, JW AF Ma, B Balachandran, U Hodges, JP Jorgensen, JD Miller, DJ Richardson, JW TI Synthesis, conductivity and oxygen diffusivity of Sr2Fe3Ox SO MATERIALS LETTERS LA English DT Article DE mixed-conducting oxides; Sr2Fe3Ox; synthesis; crystal structure; electrical conductivity; oxygen diffusivity ID O SYSTEM; COEFFICIENT; SRFECO0.5OX AB Sr2Fe3Ox samples were synthesized by solid-state reaction at 1200 degrees C in atmospheres with various oxygen partial pressures. X-ray and neutron powder diffraction experiments were conducted to determine the crystal structure. Electrical conductivity was measured by the four-probe method at elevated temperatures in atmospheres with various oxygen partial pressures. The oxygen chemical diffusion coefficient was determined by the conductivity relaxation method. Neutron powder diffraction shotvbed that the Sr2Fe3Ox material has a layered structure with an orthorhombic unit cell with lattice parameters a = 11.122 Angstrom, b = 18.98 Angstrom, c = 5.585 Angstrom, and V = 1178.97 Angstrom(3). The total conductivity of Sr2Fe3Ox increases with increasing temperature and oxygen partial pressure; at 800 degrees C in air, the conductivity is approximate to 0.5 Ohm(-1) cm(-1). Oxygen chemical diffusion coefficient increases with increasing temperature. The coefficient at 900 degrees C approximate to 1.2 X 10(-5) cm(2) s(-1), is more than one order of magnitude higher than that of the mixed-conducting Sr2Fe2CoOx material. The activation energy for oxygen diffusion in Sr2Fe3Ox, derived from the oxygen chemical diffusion coefficient, is approximate to 0.9 eV in air. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Intense Pulsed Neutron Source, Argonne, IL 60439 USA. RP Ma, B (reprint author), Argonne Natl Lab, Div Energy Technol, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Ma, Beihai/I-1674-2013; Hodges, Jason/K-1421-2013; OI Ma, Beihai/0000-0003-3557-2773; Hodges, Jason/0000-0003-3016-4578 NR 17 TC 6 Z9 6 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-577X J9 MATER LETT JI Mater. Lett. PD JUN PY 1998 VL 35 IS 5-6 BP 303 EP 308 DI 10.1016/S0167-577X(97)00270-X PG 6 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA ZX898 UT WOS:000074566500005 ER PT J AU Roy, AK Fleming, DL Lum, BY AF Roy, AK Fleming, DL Lum, BY TI Potential H-2 damage in candidate nuclear waste package container materials - Reply SO MATERIALS PERFORMANCE LA English DT Letter C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Roy, AK (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,M-S L-369, Livermore, CA 94551 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NATL ASSN CORROSION ENG PI HOUSTON PA 1440 SOUTH CREEK DRIVE, HOUSTON, TX 77084-4906 USA SN 0094-1492 J9 MATER PERFORMANCE JI Mater. Perform. PD JUN PY 1998 VL 37 IS 6 BP 7 EP 7 PG 1 WC Materials Science, Characterization & Testing SC Materials Science GA ZT352 UT WOS:000074076600002 ER PT J AU Huh, MY Cho, YS Engler, O AF Huh, MY Cho, YS Engler, O TI Effect of lubrication on the evolution of microstructure and texture during rolling and recrystallization of copper SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE lubrication; microstructure; copper ID POLYCRYSTALLINE FCC METALS; SINGLE-CRYSTALS; CUBE TEXTURE; DEFORMATION; INHOMOGENEITIES; MECHANISM; ORIGIN; GROWTH AB Two polycrystalline copper specimens were deformed by cold rolling with and without lubrication so as to achieve different deformed microstructures. The effect of the different rolling procedures on the evolution of microstructure and texture during rolling and recrystallization was studied by microstructural observations and X-ray texture analysis. In addition, local orientations in the as-deformed state were determined by selected area diffraction (SAD) in a transmission electron microscope (TEM) and, after recrystallization, by electron backscattering diffraction (EBSD) in a Scanning electron microscope (SEM). Whereas the rolling textures of the two differently rolled sheets were surprisingly similar, the microstructures strongly differed in so far as the sample rolled without lubrication contained a much larger amount of shear bands. The present results suggest that the shear component epsilon(13) caused by friction during dry rolling can effectively be dissipated by shear band formation, resulting in a rather homogeneous overall rolling texture. With regard to nucleation of recrystallization, shear bands are known to cut the typical nucleation sites of the cube-orientation, the main recrystallization texture component of rolled copper, but they are also able to act as new nucleation sites. Furthermore, growth of the new recrystallized grains is hindered by the shear bands because of microstructural and orientation discontinuities at the matrix-shear band interfaces. This led to a strong retardation of the recrystallization process and gave rise to a very fine grained microstructure and a weak recrystallization texture in the specimen cold rolled without lubrication. (C) 1998 Elsevier Science S.A. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. Korea Univ, Div Engn & Mat Sci, Seoul 136701, South Korea. RP Engler, O (reprint author), Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. NR 35 TC 31 Z9 33 U1 0 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD JUN 1 PY 1998 VL 247 IS 1-2 BP 152 EP 164 DI 10.1016/S0921-5093(97)00772-7 PG 13 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA ZZ381 UT WOS:000074723700019 ER PT J AU Phillips, C Stein, C Wein, J AF Phillips, C Stein, C Wein, J TI Minimizing average completion time in the presence of release dates SO MATHEMATICAL PROGRAMMING LA English DT Article DE scheduling; preemptive scheduling; average weighted completion time; approximation algorithms; relaxations; linear programming AB A natural and basic problem in scheduling theory is to provide good average quality of service to a stream of jobs that arrive over time. In this paper we consider the problem of scheduling n jobs that are released over time in order to minimize the average completion time of the set of jobs. In contrast to the problem of minimizing average completion time when all jobs are available at time 0, all the problems that we consider are NP-hard, and essentially nothing was known about constructing good approximations ill polynomial time. We give the first constant-factor approximation algorithms for several variants of the single and parallel machine models. Many of the algorithms are based on interesting algorithmic and structural relationships between preemptive and nonpreemptive schedules and linear programming relaxations of both, Many of the algorithms generalize to the minimization of average weighted completion time as well. (C) 1998 The Mathematical Programming Society, Inc.Published by Elsevier Science B.V. C1 Polytech Univ, Dept Comp Sci, Brooklyn, NY 11201 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Sudikoff Lab, Dept Comp Sci, Hanover, NH USA. RP Wein, J (reprint author), Polytech Univ, Dept Comp Sci, 6 Metrotech Ctr, Brooklyn, NY 11201 USA. EM wein@mem.poly.edu NR 23 TC 79 Z9 85 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0025-5610 J9 MATH PROGRAM JI Math. Program. PD JUN 1 PY 1998 VL 82 IS 1-2 BP 199 EP 223 DI 10.1007/BF01585872 PG 25 WC Computer Science, Software Engineering; Operations Research & Management Science; Mathematics, Applied SC Computer Science; Operations Research & Management Science; Mathematics GA ZZ779 UT WOS:000074766300011 ER PT J AU Dowding, KJ Blackwell, BF AF Dowding, KJ Blackwell, BF TI Joint experimental/computational techniques to measure thermal properties of solids SO MEASUREMENT SCIENCE AND TECHNOLOGY LA English DT Article ID CARBON-CARBON COMPOSITE; DESIGN AB Experimental techniques to measure the thermal properties of solids are discussed. Experimental measurements and parameter estimation techniques are used to estimate the thermal properties. The importance of experimental design is emphasized, and criteria that give insight to the parameter estimation process and experiment are cited. A code-to-code communication technique is presented, which allows standard stand-alone direct solution programs to be linked with parameter estimation codes without modification. This method is called reusable interlace technology (RIT). Aspects of this computational technique are discussed. The experimental/computational techniques are demonstrated with an experiment to estimate the thermal properties of an orthotropic carbon-carbon composite material. Two-dimensional, transient temperature and heat flux data are used to estimate two components of thermal conductivity (in the principal directions of the material) and the volumetric heat capacity. C1 Sandia Natl Labs, Thermal Sci Dept 9113, Albuquerque, NM 87185 USA. RP Sandia Natl Labs, Thermal Sci Dept 9113, POB 5800, Albuquerque, NM 87185 USA. NR 36 TC 17 Z9 19 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0957-0233 EI 1361-6501 J9 MEAS SCI TECHNOL JI Meas. Sci. Technol. PD JUN PY 1998 VL 9 IS 6 BP 877 EP 887 DI 10.1088/0957-0233/9/6/004 PG 11 WC Engineering, Multidisciplinary; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA ZV062 UT WOS:000074264500004 ER PT J AU Krulewich, DA AF Krulewich, DA TI Temperature integration model and measurement point selection for thermally induced machine tool errors SO MECHATRONICS LA English DT Article ID NEURAL-NETWORK; COMPENSATION AB This paper proposes a new method to characterize and predict thermally induced errors in machine tools. The thermal error model predicts positioning errors between the tool and workpiece that are caused by deformations in the machine structure due to heat flow from both internal and external sources. These thermally induced errors can account for as much as 70% of the dimensional errors on a machined workpiece. If thermal errors can be predicted, they can be removed in real time by the machine controller. The success of performing the prediction relies on the thermal error model being both accurate and easy to implement. In this paper, a new thermal error model is presented which capitalizes on the notion that thermally induced errors are related to the integral of the temperature field and captures that integral via the Gaussian integration technique. This approach therefore creates a simple linear model with analytical foundations, where the number and location of the sensors are selected as the Gaussian integration points along an assumed polynomial temperature profile. Advantages to this approach over many of the alternative approaches include the fact that warm-up and cool-down situations can be represented by the same model as steady-state conditions. Also, since the model is based on the analytical solution for thermally induced errors, less training data are required than other methods. Furthermore, the optimum number and location of temperature measurements are predetermined and do not require additional measurements, while some alternative approaches require a large number of measurements from many sensors to determine the subset of optimum sensor locations. Test results on a spindle show that between 93-96% of the thermally induced axial errors are predicted for a variety of spindle duty cycles. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Precis Syst & Mfg Grp, Livermore, CA 94550 USA. RP Krulewich, DA (reprint author), Univ Calif Lawrence Livermore Natl Lab, Precis Syst & Mfg Grp, 7000 East Ave,L-537, Livermore, CA 94550 USA. EM krulewic@llnl.gov NR 24 TC 35 Z9 37 U1 2 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0957-4158 J9 MECHATRONICS JI Mechatronics PD JUN PY 1998 VL 8 IS 4 BP 395 EP 412 DI 10.1016/S0957-4158(97)00059-7 PG 18 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic; Engineering, Mechanical SC Automation & Control Systems; Computer Science; Engineering GA ZW220 UT WOS:000074387700008 ER PT J AU Jayaram, R Klueh, RL AF Jayaram, R Klueh, RL TI Microstructural characterization of 5 to 9 pct Cr-2 pct W-V-Ta martensitic steels SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID FERRITIC STEELS; ATOM-PROBE; PRECIPITATION AB The microstructure of 9Cr-2W-0.25V-0.1C (9Cr-2WV), 9Cr-2W-0.25V-0.07Ta-0.1C (9Cr-2WVTa), 7Cr-2W-0.25V-0.07Ta-0.1C (7Cr-2WVTa), and 5Cr-2W-0.25V-0.07Ta-0.1C (5Cr-2WVTa) steels (all composition are in wt pct) have been characterized by analytical electron microscopy (AEM) and atom probe field ion microscopy (APFIM). These alloys have potential applications in fusion reactors because they exhibit reduced neutron activation in comparison to the conventional Cr-Mo steels. The matrix in all four alloys was 100 pct martensite. The precipitate type in the steels depended primarily on the chromium level in the alloy. In the two 9Cr steels, the stable phases were blocky M23C6 and small spherical precipitates previously identified as MC. The two lower-chromium steels contained blocky M7C3 ans small needle-shaped carbonitrides in addition to M23C6. The AEM and APFIM analyses revealed that, in the steels containing tantalum, the majority of the tantalum was in solid solution. With the exception of a few of the small spherical precipitates in low-number densities in the 9Cr-2WVTa, none of the other precipitates containing measurable tantalum. The experimentally observed phases were in agreement with those predicted by phase equilibria calculations using the ThermoCalc software. However, a similar match between the experimental and predicted values of the phase composition did not occur in some instances. Atom probe analyses directly confirmed the crucial role of trace amounts of nitrogen in the formation of vandium-rich carbonitrides as predicted by thermodynamic equilibrium calculations. C1 Univ Pittsburgh, Dept Mat Sci & Engn, Pittsburgh, PA 15261 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Jayaram, R (reprint author), Univ Pittsburgh, Dept Mat Sci & Engn, Pittsburgh, PA 15261 USA. NR 18 TC 34 Z9 36 U1 0 U2 7 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 USA SN 1073-5623 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD JUN PY 1998 VL 29 IS 6 BP 1551 EP 1558 DI 10.1007/s11661-998-0077-2 PG 8 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA ZX470 UT WOS:000074519300003 ER PT J AU Santo Domingo, JW Kaufman, MG Klug, MJ Holben, WE Harris, D Tiedje, JM AF Santo Domingo, JW Kaufman, MG Klug, MJ Holben, WE Harris, D Tiedje, JM TI Influence of diet on the structure and function of the bacterial hindgut community of crickets SO MOLECULAR ECOLOGY LA English DT Article DE gut fermentation; hindgut microbial community; insect gut; microbial community structure ID COCKROACH GUT; DNA; MICROORGANISMS AB The effect of diets varying in carbohydrate and protein content on the structure and function of the hindgut microbiota of crickets was evaluated by determining bacterial densities, fermentation activity, and guanine plus cytosine (G + C) profiles of the DNA extracted from the microbial hindgut community. DNA isolated from the gut community was fractionated and quantified according to G + C content as a comprehensive, coarse-level measure of the composition and structure of the community. The bacterial densities measured by direct counts were not significantly different among the four diets. The crickets were initially reared in the laboratory on cricket chow, which resulted in a hindgut community dominated by bacteria with a G + C content between 32% and 57%. Crickets shifted to an alfalfa diet showed a similar hindgut community G + C profile, although microbial populations with DNA between 35% and 45% G + C were more abundant in alfalfa- than chow-fed crickets. The apparent complexity of the gut community was reduced in crickets fed beet-pulp and protein-based diets compared to those fed chow and alfalfa, and was dominated by populations with a low percentage G + C content. Hindgut communities in crickets fed pulp and protein diets also showed a decrease in hydrogen and carbon dioxide production, suggesting that these diets affected the biochemical activity of the hindgut community. The protein-based diet resulted in a decrease in the rate of evolution of volatile fatty acids, while the ratio of butyrate production to acetate and propionate production was significantly higher in these crickets. Our results show the emergence of a new microbial community structure concomitant with changes in microbial biochemical activity due to shifts in the cricket's dietary regime. C1 Michigan State Univ, Dept Microbiol, E Lansing, MI 48824 USA. Michigan State Univ, Ctr Microbial Ecol, E Lansing, MI 48824 USA. Michigan State Univ, Wk Kellogg Biol Stn, Hickory Corners, MI 49060 USA. Michigan State Univ, Dept Crop & Soil Sci, E Lansing, MI 48824 USA. RP Santo Domingo, JW (reprint author), Westinghouse Savannah River Co, Savannah River Technol Ctr, Bldg 704-8T, Aiken, SC 29808 USA. EM j.santodomingo@srs.gov NR 34 TC 42 Z9 42 U1 3 U2 28 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0962-1083 J9 MOL ECOL JI Mol. Ecol. PD JUN PY 1998 VL 7 IS 6 BP 761 EP 767 DI 10.1046/j.1365-294x.1998.00390.x PG 7 WC Biochemistry & Molecular Biology; Ecology; Evolutionary Biology SC Biochemistry & Molecular Biology; Environmental Sciences & Ecology; Evolutionary Biology GA ZU801 UT WOS:000074236300009 ER PT J AU Hoffman, PA AF Hoffman, PA TI Materials needs for high-efficiency, low-emission gas turbines being developed for the 21st-century electric power generation SO MRS BULLETIN LA English DT Editorial Material C1 US DOE, Off Ind Technol, Washington, DC 20585 USA. RP Hoffman, PA (reprint author), US DOE, Off Ind Technol, Washington, DC 20585 USA. NR 0 TC 2 Z9 2 U1 0 U2 4 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0883-7694 J9 MRS BULL JI MRS Bull. PD JUN PY 1998 VL 23 IS 6 BP 4 EP + PG 3 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA ZU489 UT WOS:000074203200004 ER PT J AU Rigney, DA Hammerberg, JE AF Rigney, DA Hammerberg, JE TI Unlubricated sliding behavior of metals SO MRS BULLETIN LA English DT Article ID PLASTIC-DEFORMATION; FRICTION; DYNAMICS C1 Ohio State Univ, Dept Mat Sci & Engn, Columbus, OH 43210 USA. Univ Calif Los Alamos Natl Lab, Appl Theoret & Comp Phys Div, Los Alamos, NM 87545 USA. RP Rigney, DA (reprint author), Ohio State Univ, Dept Mat Sci & Engn, Columbus, OH 43210 USA. NR 23 TC 60 Z9 62 U1 2 U2 10 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0883-7694 J9 MRS BULL JI MRS Bull. PD JUN PY 1998 VL 23 IS 6 BP 32 EP 36 PG 5 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA ZU489 UT WOS:000074203200023 ER PT J AU Grant, WF Owens, ET AF Grant, WF Owens, ET TI Chromosome aberration assays in Crepis for the study of environmental mutagens SO MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH LA English DT Article; Proceedings Paper CT Workshop on Sources, Effects, and Potential Hazards of Genotoxic Complex Mixtures in the Environment at the 28th Annual Meeting of the Environmental-Mutagen-Society CY APR 20, 1997 CL MINNEAPOLIS, MINNESOTA SP Environm Mutagen Soc DE Crepis capillaris; Crepis tectorum; Compositae; plant bioassay; chromosome aberrations; polyploidy; C-mitosis ID GENE-TOX PROGRAM; CAPILLARIS CELLS; DNA-SYNTHESIS; B-CHROMOSOME; CHEMICALS; MUTATIONS; BATTERIES; BIOASSAYS; PATTERNS; SYSTEM AB Crepis capillaris (2n = 6) is an excellent plant for the assay of chromosome aberrations after chemical treatment. C. tectorum (2n = 8) has been used also in mutagenic studies, but to a much lesser extent. A protocol has been given for using root tips to study the cytological endpoints, such as chromosome breaks and exchanges, which follow the testing of chemicals in somatic cells. Meiotic endpoints have not been used in C. capillaris for testing potential chemical mutagens but should be considered, especially a meiotic micronucleus assay. From a literature survey, 81 chemicals are tabulated that have been assayed in 162 Crepis assays for their clastogenic effects. Of the 162 assays that have been carried out, 40 are reported at giving a positive reaction (i.e., causing chromosome aberrations), 97 positive and with a dose response, 7 borderline positive, and 17 negative. Eighty-five percent of the chemicals gave a definite positive response. Assays for one chemical gave contrary results, and were not included in the above tabulation. The Crepis bioassay has been shown to be an excellent plant bioassay for assessing chromosome damage induced by chemicals and environmental pollutants. (C) 1998 Elsevier Science B.V. All rights reserved. C1 McGill Univ, Dept Plant Sci, St Anne De Bellevue, PQ H9X 3V9, Canada. Oak Ridge Natl Lab, Div Life Sci, Toxicol & Risk Anal Sect, Human Genome & Toxicol Grp, Oak Ridge, TN 37830 USA. RP Grant, WF (reprint author), McGill Univ, Dept Plant Sci, POB 4000,Macdonald Campus, St Anne De Bellevue, PQ H9X 3V9, Canada. EM ef16@musica.mcgill.ca NR 189 TC 14 Z9 15 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1383-5742 J9 MUTAT RES-REV MUTAT JI Mutat. Res.-Rev. Mutat. Res. PD JUN PY 1998 VL 410 IS 3 BP 291 EP 307 DI 10.1016/S1383-5742(98)00004-0 PG 17 WC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology SC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology GA ZU324 UT WOS:000074185300006 PM 9630682 ER PT J AU Huang, L Hofer, F Martin, GS Kim, SH AF Huang, L Hofer, F Martin, GS Kim, SH TI Structural basis for the interaction of Ras with RaIGDS SO NATURE STRUCTURAL BIOLOGY LA English DT Letter ID NUCLEOTIDE DISSOCIATION STIMULATOR; H-RAS; R-RAS; PROTEIN; KINASE; TRANSFORMATION; FAMILY; P21; ACTIVATION; DOMAINS AB The Ras protein signals to a number of distinct pathways by interacting with diverse downstream effecters. Among the effecters of Ras are the Raf kinase and RalGDS, a guanine nucleotide dissociation stimulator specific for Ral. Despite the absence of significant sequence similarities, both effecters bind directly to Ras, but with different specificities. We report here the 2.1 Angstrom crystal structure of the complex between Ras and the Ras-interacting domain (RID) of RalGDS. This structure reveals that the beta-sheet of the RID joins the switch I region of Ras to form an extended beta-sheet with a topology similar to that found in the Rap-Raf complex. However, the side chain interactions at the joining junctions of the two interacting systems and the relative orientation of the two binding domains are distinctly different. Furthermore, in the case of the Ras-RID complex a second RID molecule also interacts with a different part of the Ras molecule, the switch II region. These findings account for the cross-talk between the Ras and Ral pathways and the specificity with which Ras distinguishes the two effecters. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mol & Cell Biol, Berkeley, CA 94720 USA. RP Kim, SH (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 32 TC 163 Z9 165 U1 2 U2 6 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 JUN PY 1998 VL 5 IS 6 BP 422 EP 426 DI 10.1038/nsb0698-422 PG 5 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA ZQ612 UT WOS:000073885500008 PM 9628477 ER PT J AU Nogales, E Downing, KH Amos, LA Lowe, J AF Nogales, E Downing, KH Amos, LA Lowe, J TI Tubulin and FtsZ form a distinct family of GTPases SO NATURE STRUCTURAL BIOLOGY LA English DT Article ID DIVISION PROTEIN FTSZ; GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE; PROKARYOTIC HOMOLOG; BETA-TUBULIN; BINDING-SITE; HYDROLYSIS; SEQUENCE; PROTOFILAMENTS; PROGRAM; SHEETS AB Tubulin and FtsZ share a common fold of two domains connected by a central helix. Structure-based sequence alignment shows that common residues localize in the nucleotide-binding site and a region that interacts with the nucleotide of the next tubulin subunit in the protofilament, suggesting that tubulin and FtsZ use similar contacts to form filaments. Surfaces that would make lateral interactions between protofilaments or interact with motor proteins are, however, different. The highly conserved nucleotide-binding sites of tubulin and FtsZ clearly differ from those of EF-Tu and other GTPases, while resembling the nucleotide site of glyceraldehyde-3-phosphate dehydrogenase. Thus, tubulin and FtsZ farm a distinct family of GTP-hydrolyzing proteins. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Donner Lab, Berkeley, CA 94720 USA. MRC, Mol Biol Lab, Cambridge CB2 2QH, England. RP Nogales, E (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Donner Lab, 1 Cyclotron Rd, Berkeley, CA 94720 USA. EM enogales@lbl.gov RI Lowe, Jan/B-3882-2011 NR 43 TC 330 Z9 342 U1 5 U2 26 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 JUN PY 1998 VL 5 IS 6 BP 451 EP 458 DI 10.1038/nsb0698-451 PG 8 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA ZQ612 UT WOS:000073885500014 PM 9628483 ER PT J AU Rao, NSV Protopopescu, V AF Rao, NSV Protopopescu, V TI Function estimation by feedforward sigmoidal networks with bounded weights SO NEURAL PROCESSING LETTERS LA English DT Article DE feedforward sigmoid networks; function estimation; PAC learning AB We address the problem of estimating a function f : [0, 1](d) bar right arrow [-L, L] by using feedforward sigmoidal networks with a single hidden layer and bounded weights. The only information about the function is provided by an identically independently distributed sample generated according to an unknown distribution. The quality of the estimate is quantified by the expected cost functional and depends on the sample size. We use Lipschitz properties of the cost functional and of the neural networks to derive the relationship between performance bounds and sample sizes within the framework of Valiant's probably approximately correct learning. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. OI Rao, Nageswara/0000-0002-3408-5941 NR 16 TC 8 Z9 8 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 1370-4621 J9 NEURAL PROCESS LETT JI Neural Process. Lett. PD JUN PY 1998 VL 7 IS 3 BP 125 EP 131 DI 10.1023/A:1009640613940 PG 7 WC Computer Science, Artificial Intelligence; Neurosciences SC Computer Science; Neurosciences & Neurology GA ZG367 UT WOS:000072994500001 ER PT J AU Rooney, WD Miller, RG Gelinas, D Schuff, N Maudsley, AA Weiner, MW AF Rooney, WD Miller, RG Gelinas, D Schuff, N Maudsley, AA Weiner, MW TI Decreased N-acetylaspartate in motor cortex and corticospinal tract in ALS SO NEUROLOGY LA English DT Article ID AMYOTROPHIC-LATERAL-SCLEROSIS; MAGNETIC-RESONANCE SPECTROSCOPY; POSITRON EMISSION TOMOGRAPHY; TEMPORAL-LOBE EPILEPSY; HUMAN-BRAIN INVIVO; IN-VIVO; NEURON DISEASE; MULTIPLE-SCLEROSIS; PROTON; METABOLITES AB The primary objectives of this study were to test whether 1) N-acetylaspartate (NAA), a neuronal marker, is reduced in motor cortex and corticospinal-tract (CST) brain regions of ALS patients; and 2) motor cortex NAA correlates to a clinical measurement of upper motor neuron function in ALS patients. Ten probable or definite ALS patients and nine neurologically normal control subjects were studied. Three axial planes of two-dimensional H-1 MRSI data were collected, using a single spin-echo multislice sequence (TE140/TR2000). Two of the H-1 MRSI planes were positioned superior to the lateral ventricles, and one plane was positioned at the level of the internal capsule. Spectroscopy voxels were selected from motor cortex, frontal cortex, parietal cortex, medial gray matter, centrum semiovale white matter, anterior internal capsule, and posterior internal capsule. Peak integrals were obtained for the three major H-1 MRSI singlet resonances, NAA, creatine and phosphocreatine (Cr), and cholines (Cho). Maximum finger-tap rate was used as a clinical measurement of upper motor neuron function. In ALS, brain NAA/(Cho + Cr) was reduced 19% (p = 0.024) in the motor cortex and 16% (p = 0.021) in the CST (centrun semiovale and posterior internal capsule) regions. NAA/ (Cho+Cr) was not reduced in frontal cortex, parietal cortex, medial gray matter, or anterior internal capsule. There was a significant relation between ALS motor cortex NAA/(Cho+Cr) and maximum finger-tap rate (r = 0.80; p = 0.014). NAA/(Cho+Cr) was reduced in motor cortex and CST regions and unchanged in other brain regions of ALS patients when compared with controls. These findings are consistent with the known distribution of neuronal loss in ALS. The positive correlation between motor cortex NAA/(Cho+Cr) and maximum finger-tap rate suggests that reduced NAA/(Cho+Cr) is a surrogate marker of motor cortex neuron loss in ALS. These findings support the study of 1H MRSI NAA measurement as an objective and quantitative measurement of upper motor neuron dysfunction in ALS. C1 Dept Vet Affairs Med Ctr, Magnet Resonance Unit, San Francisco, CA USA. Univ Calif San Francisco, Dept Neurol, San Francisco, CA 94143 USA. Univ Calif San Francisco, Dept Radiol, San Francisco, CA 94143 USA. Univ Calif San Francisco, Dept Med, San Francisco, CA 94143 USA. Calif Pacific Med Ctr, Dept Neurol, San Francisco, CA USA. RP Rooney, WD (reprint author), Brookhaven Natl Lab, Dept Chem, High Field MRI Lab, Upton, NY 11973 USA. FU NCI NIH HHS [CA48815]; NIA NIH HHS [R01AG10897] NR 32 TC 88 Z9 91 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 USA SN 0028-3878 J9 NEUROLOGY JI Neurology PD JUN PY 1998 VL 50 IS 6 BP 1800 EP 1805 PG 6 WC Clinical Neurology SC Neurosciences & Neurology GA ZU712 UT WOS:000074226700046 PM 9633731 ER PT J AU Kissick, MW Callen, JD Fredrickson, ED AF Kissick, MW Callen, JD Fredrickson, ED TI Conditions and behaviour related to non-local electron heat transport on TFTR SO NUCLEAR FUSION LA English DT Article ID PULSE-PROPAGATION; TOKAMAK; INTERFEROMETER; DIFFUSIVITY; TURBULENCE; INJECTION; PLASMAS AB A database of 70 distinct and randomly collected cold pulse cases from TFTR is analysed. Observations show a striking parameter regime cut-off for the presence of non-local transient transport and coincident magnetohydrodynamic (MHD) (1/1 mode) activity, as well as for changes in the radial speed of the non-local transport effect and changes in the sawtooth period. A significant link is demonstrated between electron heat transport and MHD properties through observation of a common cut-off in the parameter n(e)(0)/T-e(0)(1/2) and a common threshold for changes in the radial speed of propagation and in the sawtooth period. Auxiliary heating (via energetic neutral beams) destroys whatever process is responsible for the non-local transport effect, unless the discharge contains significant amounts of injected tritium. These observations are evidence, albeit circumstantial, that changes in the propagation of some MHD related phenomenon are responsible for a large fraction of the electron heat transport. This propagation is then probably a function of n(e)(0)/T-e(0)(1/2), ion mass and, possibly, beam power. An analysis of ohmic cases indicates the non-local transport effects that occur when the electrons are collisionally thermally decoupled from the ions. C1 Univ Calif Los Angeles, Los Angeles, CA 90024 USA. Univ Wisconsin, Madison, WI 53706 USA. Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08544 USA. RP Kissick, MW (reprint author), Univ Calif Los Angeles, Los Angeles, CA 90024 USA. NR 27 TC 38 Z9 38 U1 0 U2 2 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 JUN PY 1998 VL 38 IS 6 BP 821 EP 833 DI 10.1088/0029-5515/38/6/304 PG 13 WC Physics, Fluids & Plasmas SC Physics GA 104FE UT WOS:000075003400004 ER PT J AU Sesnic, S Kaita, R Batha, SH Bell, RE Bernabei, S Chance, MS De la Luna, E Dunlap, JL England, AC Isler, RC Jones, S Kaye, SM Kesner, J Kugel, HW LeBlanc, B Levinton, FM Luckhardt, SC Manickam, J Okabayashi, M Ono, M Paoletti, F Paul, SF Post-Zwicker, AP Sanz, JS Sauthoff, NR Seki, T Takahashi, H Tighe, W Von Goeler, S Woskov, P Zolfaghari, A AF Sesnic, S Kaita, R Batha, SH Bell, RE Bernabei, S Chance, MS De la Luna, E Dunlap, JL England, AC Isler, RC Jones, S Kaye, SM Kesner, J Kugel, HW LeBlanc, B Levinton, FM Luckhardt, SC Manickam, J Okabayashi, M Ono, M Paoletti, F Paul, SF Post-Zwicker, AP Sanz, JS Sauthoff, NR Seki, T Takahashi, H Tighe, W Von Goeler, S Woskov, P Zolfaghari, A TI Magnetohydrodynamic behaviour during core transport barrier experiments with ion Bernstein wave heating in PBX-M: I ELMs, fluctuations and crash events SO NUCLEAR FUSION LA English DT Article ID DIII-D TOKAMAK; HEATED DIVERTOR DISCHARGES; POLOIDAL ROTATION; HIGH CONFINEMENT; EDGE TURBULENCE; MODES; SHEAR; SUPPRESSION; TRANSITION; PROFILE AB If the ion Bernstein wave (IBW) heating power in an H mode discharge of the PBX-M experiment exceeds a threshold power of about 200 kW, a core transport barrier is created in the central region of the plasma. At lower neutral beam injection (NBI) powers, the core barrier is accompanied by an edge L mode. The high edge localized mode (ELM) repetition frequency (1 kHz) prevents the creation of a strong barrier, so the edge first has to make an H-to-L transition before a strong core transport barrier can be created. At higher NBI powers, the ELM repetition frequency is lowered to less than 200 Hz, which allows the immediate creation of a strong core barrier. Edge localized mode loss, which propagates radially first on a fast (non-diffusive) and then on a slow (diffusive) time-scale all the way to the plasma core, is strongly reduced in the core barrier region. Correlated with the reduced ELM. loss, the fluctuations in the core barrier region are also strongly reduced, both during the ELM and during the quiet periods between the ELMs, There is strong evidence that the IBW induced poloidal flow shear is responsible for the stabilization of core turbulence and the creation of the core transport barrier. The large perpendicular E x B flow shear component of the measured toroidal velocity in co-injection neutral beam heated discharges seems to be largely cancelled by the ion diamagnetic drift shear produced by large ion pressure gradients in the core barrier region. The value of IBW induced poloidal flow has not been experimentally determined, but its numerical value is found to be a factor of 4 larger than either the toroidal velocity or the ion diamagnetic drift, shear components, leaving only IBW induced flow shear as the most probable cause for the turbulence stabilization. The core turbulence suppression and the creation of the core transport barrier is also consistent with expectations from a comparison between the E x B flow shear rate and a rough estimate of the linear ion temperature gradient (ITG) growth rate. The presence of the core barrier region also strongly modifies the other MHD events: crashes on the q = 1.5, 2 surfaces and the disruption. C1 Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08544 USA. Max Planck Inst Plasma Phys, EURATOM, IPP Assoc, Garching, Germany. Fus Phys & Technol, Torrance, CA USA. EURATOM, CIEMAT Fus, Madrid, Spain. Oak Ridge Natl Lab, Div Fus Energy, Oak Ridge, TN 37831 USA. MIT, Plasma Sci & Fus Ctr, Cambridge, MA 02139 USA. Natl Inst Fus Sci, Nagoya, Aichi, Japan. RP Sesnic, S (reprint author), Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08544 USA. EM ssesnic@ipp.mpg.de OI Isler, Ralph/0000-0002-5368-7200 NR 42 TC 5 Z9 5 U1 0 U2 0 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5, PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD JUN PY 1998 VL 38 IS 6 BP 835 EP 859 DI 10.1088/0029-5515/38/6/305 PG 25 WC Physics, Fluids & Plasmas SC Physics GA 104FE UT WOS:000075003400005 ER PT J AU Sesnic, S Gunter, S Pinches, SD AF Sesnic, S Gunter, S Pinches, SD TI Magnetohydrodynamic behaviour during core transport barrier experiments with ion Bernstein wave heating in PBX-M: II-n=m-1 and n=m modes SO NUCLEAR FUSION LA English DT Article ID KINETIC BALLOONING MODES; MAGNETIC ISLANDS; NONLINEAR DYNAMICS; TOROIDAL ROTATION; TOKAMAKS; PRESSURE; EXCITATION; PARTICLES; PLASMAS; TFTR AB Two new types of high frequency (HF) MHD mode activity are observed when a core transport barrier is formed during ion Bernstein wave (IBW) heating in PBX-M. These modes, localized in the core transport barrier, seem to be mainly responsible for the soft saturation in the strength of the core transport barrier. The two types of HF mode activity are determined by the presence or absence of a strong 1/1 mode. The n = m modes are observed with the 1/1 mode, while the n = m - 1 modes are seen when the 1/1 mode is absent. The m numbers of both of these modes vary between 4 and 13. They all seem to be coupled and rotate as a rigid body. The n = m - 1 modes seemed to be narrowly localized on their corresponding rational surface, i.e. q = m/(m - 1). The modes are ballooning-like, and their amplitudes increase with increasing beta. Calculations with the CASTOR code show that the n = m - 1 modes are most probably pressure driven tearing modes, but the possibility of kinetic ballooning modes (KBMs) cannot be fully excluded. The n = m modes appear on or around the q = 1 surface, and are localized at the X point of the 1/1 mode island. The frequency offset of the n = m modes, which is too low for a TAE, is shown to be consistent with P-induced toroidal Alfven eigenmodes (BAEs). C1 Max Planck Inst Plasma Phys, EURATOM Assoc, D-85748 Garching, Germany. Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08544 USA. Fus Phys & Technol, Torrance, CA USA. EURATOM, CIEMAT Fus, Madrid, Spain. Oak Ridge Natl Lab, Div Fus Energy, Oak Ridge, TN 37831 USA. MIT, Plasma Sci & Fus Ctr, Cambridge, MA 02139 USA. Natl Inst Fus Sci, Nagoya, Aichi, Japan. RP Sesnic, S (reprint author), Max Planck Inst Plasma Phys, EURATOM Assoc, Boltzmannstr 2, D-85748 Garching, Germany. EM ssesnic@ipp.mpg.de OI Isler, Ralph/0000-0002-5368-7200 NR 28 TC 2 Z9 2 U1 0 U2 0 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5, PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD JUN PY 1998 VL 38 IS 6 BP 861 EP 884 DI 10.1088/0029-5515/38/6/306 PG 24 WC Physics, Fluids & Plasmas SC Physics GA 104FE UT WOS:000075003400006 ER PT J AU Goniche, M Guilhem, D Bibet, P Froissard, P Litaudon, X Rey, G AF Goniche, M Guilhem, D Bibet, P Froissard, P Litaudon, X Rey, G TI Enhanced heat flux in the scrape-off layer due to electrons accelerated in the near field of lower hybrid grills SO NUCLEAR FUSION LA English DT Article ID TORE SUPRA; PLASMAS; TOKAMAK AB As a result of experimental observations of localized heat flux on components magnetically connected to radiating waveguides in Tore Supra and in TdeV, the acceleration of electrons near lower hybrid (LH) antennas has been investigated. A simple analytical model has been developed to compute the dynamics of the particles in the near field approximation. Landau damping of the very high N-parallel to (20 < N-parallel to < 100) component of the launched spectrum on the thermal electrons of the scrape-off layer (SOL) is found to occur. Simulation of a typical LH pulse in Tore Supra indicates that the electrons can be accelerated up to 2-3 keV. Modelling of the interaction of this fast electron population with the edge plasma allows a calculation of the heat flux on plasma facing components that are magnetically connected to the antenna. Model results and the results of experiments in Tore Supra and TdeV are compared. The calculated heat fluxes are found to be fairly consistent when the variation of convective heat flux at the grill aperture is taken into account. From this analysis, it is concluded that, for an LH power density of 25 MW/m(2), the resulting heat flux along the field lines (3.5 MW/m(2)) is manageable for the components connected to the antenna, provided that good coupling can be maintained at a low density in front of the grill. C1 CEA, EURATOM Assoc, CEA Cadarache, St Paul Les Durance, France. Ctr Canadien Fus Magnet, Varennes, PQ J3X 1S1, Canada. Oak Ridge Natl Lab, Oak Ridge, TN USA. RP CEA, EURATOM Assoc, CEA Cadarache, St Paul Les Durance, France. EM goniche@drfc.cad.cea.fr NR 32 TC 64 Z9 64 U1 0 U2 10 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0029-5515 EI 1741-4326 J9 NUCL FUSION JI Nucl. Fusion PD JUN PY 1998 VL 38 IS 6 BP 919 EP 937 DI 10.1088/0029-5515/38/6/309 PG 19 WC Physics, Fluids & Plasmas SC Physics GA 104FE UT WOS:000075003400009 ER PT J AU Hermon, H Schieber, M James, RB Lund, J Antolak, AJ Morse, DH Kolesnikov, NNP Ivanov, YN Goorsky, MS Yoon, H Toney, J Schlesinger, TE AF Hermon, H Schieber, M James, RB Lund, J Antolak, AJ Morse, DH Kolesnikov, NNP Ivanov, YN Goorsky, MS Yoon, H Toney, J Schlesinger, TE TI Homogeneity of CdZnTe detectors SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 5th International Workshop on GaAs Detectors and Related Compounds CY JUN 17-20, 1997 CL UDINE, ITALY ID PRESSURE BRIDGMAN METHOD; GAMMA-RAY DETECTORS; X-RAY; RADIATION DETECTORS; PERFORMANCE; EPITAXY; CDTE AB We describe the current state of nuclear radiation detectors produced from single crystals of Cd1-xZnxTe (CZT), with 0.04 < x < 0.4, grown by the vertical high pressure Bridgman (VHPB) method. The crystals investigated were grown commercially both in the USA and at the Institute of Solid State Physics, Chernogolska, Russia. The CZT was evaluated by Sandia National Laboratories and the UCLA and CMU groups using proton-induced X-ray emission (PIXE), X-ray diffraction (XRD), photoluminescence (PL), infrared (IR) transmission microscopy, leakage current measurements and response to nuclear radiation. We discuss the homogeneity of the various CZT crystals based on the results from these measurement techniques. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Hebrew Univ Jerusalem, IL-91904 Jerusalem, Israel. Sandia Natl Labs, Livermore, CA 94550 USA. Russian Acad Sci, Inst Solid State Phys, Chernogolovka 142432, Russia. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. RP Schieber, M (reprint author), Hebrew Univ Jerusalem, IL-91904 Jerusalem, Israel. EM Schieber@vms.huji.ac.il NR 30 TC 7 Z9 7 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 JUN 1 PY 1998 VL 410 IS 1 BP 100 EP 106 DI 10.1016/S0168-9002(98)00184-3 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 101QN UT WOS:000074879800019 ER PT J AU Schieber, M Zuck, A Melekhov, L Nissenbaum, J Turchetta, R Dulinski, W Husson, D Riester, JL AF Schieber, M Zuck, A Melekhov, L Nissenbaum, J Turchetta, R Dulinski, W Husson, D Riester, JL TI Radiation-hard polycrystalline mercuric iodide semiconductor particle counters SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 5th International Workshop on GaAs Detectors and Related Compounds CY JUN 17-20, 1997 CL UDINE, ITALY ID NOISE AB Mercuric iodide polycrystalline radiation detectors, which can act as nuclear particle counters and for large area imaging devices, have been fabricated using three different methods. Response to X-and gamma rays, beta particles and to 100 GeV muons, as well as radiation hardness results are briefly described. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Hebrew Univ Jerusalem, IL-91904 Jerusalem, Israel. Sandia Natl Labs, Livermore, CA 94556 USA. ULP, IN2P3, LEPSI, Strasbourg, France. RP Schieber, M (reprint author), Hebrew Univ Jerusalem, IL-91904 Jerusalem, Israel. EM schieber@vms.huji.ac.il NR 8 TC 9 Z9 9 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 EI 1872-9576 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUN 1 PY 1998 VL 410 IS 1 BP 107 EP 110 DI 10.1016/S0168-9002(98)00189-2 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 101QN UT WOS:000074879800020 ER PT J AU De Geronimo, G AF De Geronimo, G TI In view of low-noise and low-power GaAs front-ends SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 5th International Workshop on GaAs Detectors and Related Compounds CY JUN 17-20, 1997 CL UDINE, ITALY ID CHARGE MEASUREMENTS; OPTIMUM FILTERS AB The use of GaAs in front-end electronics for radiation detection systems has been widely investigated by many authors and several prototypes of GaAs front-ends have been proposed. This work is a review and deepening of the criteria for the design of a low noise and low-power GaAs front-end. Remarks on the choice of the optimum bins point and gate width of the input transistor and on the choice of the shaping an discussed. A comparison of several GaAs FETs in terms of low-frequency noise and achievable resolution is also shown. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Politecn Milan, Dipartimento Elettr & Informat, I-20133 Milan, Italy. Ist Nazl Fis Nucl, Sez Milano, I-20133 Milan, Italy. RP De Geronimo, G (reprint author), Brookhaven Natl Lab, Instrumentat Div, Bldg 535B, Upton, NY 11973 USA. EM degeronimo@bnl.gov 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 0168-9002 EI 1872-9576 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUN 1 PY 1998 VL 410 IS 1 BP 124 EP 128 DI 10.1016/S0168-9002(98)00192-2 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 101QN UT WOS:000074879800023 ER PT J AU Lykken, J Poppitz, E Trivedi, SP AF Lykken, J Poppitz, E Trivedi, SP TI M(ore) on chiral gauge theories from D-branes SO NUCLEAR PHYSICS B LA English DT Article DE superstrings; supersymmetry; gauge theory; nonperturbative; D-branes ID ORIENTIFOLDS; CONSISTENCY; STRINGS AB We consider a brane configuration consisting of intersecting Neveu-Schwarz five-branes, Dirichlet four-branes, and an orientifold four-plane in a C-2/Z(3) orbifold background. We show that the low-energy dynamics is described by a four-dimensional gauge theory with N = 1 supersymmetry and SO(N + 4) x SU(N) or SP(2M) x SU(2M + 4) gauge symmetry. The matter content of this theory is chiral. In particular, the SU group has one matter field in the antisymmetric tenser or symmetric tenser representation and several fields in the fundamental and antifundamental representations. We discuss various consistency checks on these theories. By considering the brane configuration in M-theory we deduce the spectral curves for these theories. Finally, we consider the effects of replacing the orbifold background with a non-singular ALE space (both with and without an orientifold plane) and show that it leaves the spectral curves unchanged. (C) 1998 Elsevier Science B.V. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. RP Lykken, J (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 38 TC 20 Z9 20 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 JUN 1 PY 1998 VL 520 IS 1-2 BP 51 EP 74 DI 10.1016/S0550-3213(98)00186-2 PG 24 WC Physics, Particles & Fields SC Physics GA ZV797 UT WOS:000074342200003 ER PT J AU Gerber, CE AF Gerber, CE CA CDF DO collaborations TI Production of gauge bosons at the Tevatron SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 5th San Miniato Topical Seminar on the Irresistible Risk of the Standard Model CY APR 21-25, 1997 CL CASSA RISPARMO SAN MINIATO, CTR STUDI CAPPUCINI, SAN MINIATO TODESCO, ITALY SP Italian Inst Nucl Phys, Univ Bologna, Univ Florence, Regione Toscana, Electr & Instrumentat Firm CAEN HO CASSA RISPARMO SAN MINIATO, CTR STUDI CAPPUCINI ID YAN K-FACTOR; P(P)OVER-BAR COLLISIONS; ROOT-S=1.8 TEV; ORDER AB The CDF and DO collaborations have used recent data, taken at the Tevatron to perform QCD tests with W and Z bosons decaying leptonically. DO measures the production cross section times branching ratio for W and Z bosons and determines the branching ratio B(W --> lv) = (10.43 +/- 0.44)% (l = e, mu). This also gives an indirect measurement of the total width of the W boson: Gamma w = 2.16 +/- 0.09 GeV. The W cross section times branching ratio into tau leptons is measured to be sigma((p) over bar p --> W + X)B(W --> tau v) = 2.38 +/- 0.13 nb, from which the ratio of the coupling constants is determined: g(tau)(W)/g(e)(W) = 1.004 +/- 0.019 +/- 0.026. DO's measurement of the differential d sigma/dP(T) distribution for the Z boson decaying to electrons, discriminates between different phenomenologic vector boson production models. CDF measures the cross section for the Drell-Yan continuum, and extracts improved limits on compositeness scales for quarks and leptons of Lambda(ql) similar to 3 - 6 TeV, depending on the model. Studies of W + Jet production at CDF and DO find that the QCD prediction underestimates the production rate of W + 1 Jet events by about a factor of 2 as measured by both collaborations. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Gerber, CE (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JUN PY 1998 VL 65 BP 84 EP 89 DI 10.1016/S0920-5632(97)00981-X PG 6 WC Physics, Particles & Fields SC Physics GA ZG234 UT WOS:000072980600014 ER PT J AU Diehl, HT AF Diehl, HT CA DO CDF Collaborations TI Boson pair production and triple gauge couplings SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 5th San Miniato Topical Seminar on the Irresistible Risk of the Standard Model CY APR 21-25, 1997 CL CASSA RISPARMO SAN MINIATO, CTR STUDI CAPPUCINI, SAN MINIATO TODESCO, ITALY SP Italian Inst Nucl Phys, Univ Bologna, Univ Florence, Regione Toscana, Electr & Instrumentat Firm CAEN HO CASSA RISPARMO SAN MINIATO, CTR STUDI CAPPUCINI ID ROOT-S=1.8 TEV; P(P)OVER-BAR COLLISIONS; PHOTON COUPLINGS; GAMMA COUPLINGS; WZ PRODUCTION; LIMITS; WW; SEARCH AB The DO and CDF Collaborations measure boson pair production including W gamma, WW, WZ, ZZ and Z gamma production in p (p) over bar collisions at root 8 = 1800 GeV. New results, from direct measurements, are described including W gamma, WW, and Z gamma production cross sections and limits on non-Standard Model triple gauge boson couplings. The limits on anomalous WW gamma, WWZ, Z gamma gamma and ZZ gamma couplings are the most restrictive available. Prospects for Run II are discussed. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Diehl, HT (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. 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 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JUN PY 1998 VL 65 BP 103 EP 108 DI 10.1016/S0920-5632(97)00984-5 PG 6 WC Physics, Particles & Fields SC Physics GA ZG234 UT WOS:000072980600017 ER PT J AU Willocq, S AF Willocq, S CA SLD Collaboration TI B physics at SLD SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 5th San Miniato Topical Seminar on the Irresistible Risk of the Standard Model CY APR 21-25, 1997 CL CASSA RISPARMO SAN MINIATO, CTR STUDI CAPPUCINI, SAN MINIATO TODESCO, ITALY SP Italian Inst Nucl Phys, Univ Bologna, Univ Florence, Regione Toscana, Electr & Instrumentat Firm CAEN HO CASSA RISPARMO SAN MINIATO, CTR STUDI CAPPUCINI AB We review recent B physics results obtained in polarized e(+)e(-) interactions at the SLC by the SLD experiment. The excellent 3-D vertexing capabilities of SLD are exploited to extract precise B+ and B-d(0) lifetimes, as well as measurements of the time evolution of B-d(0) - <(B-d(0))over bar> mixing. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Willocq, S (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 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 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JUN PY 1998 VL 65 BP 210 EP 214 DI 10.1016/S0920-5632(97)01003-7 PG 5 WC Physics, Particles & Fields SC Physics GA ZG234 UT WOS:000072980600036 ER PT J AU Li, QZ AF Li, QZ CA DO collaboration TI Recent DO results on the top quark SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 5th San Miniato Topical Seminar on the Irresistible Risk of the Standard Model CY APR 21-25, 1997 CL CASSA RISPARMO SAN MINIATO, CTR STUDI CAPPUCINI, SAN MINIATO TODESCO, ITALY SP Italian Inst Nucl Phys, Univ Bologna, Univ Florence, Regione Toscana, Electr & Instrumentat Firm CAEN HO CASSA RISPARMO SAN MINIATO, CTR STUDI CAPPUCINI AB Recent results on top quark physics with the DO experiment in (p) over bar p collisions root s = 1.8 TeV for an integrated luminosity of 125 pb(-1) are reported. The direct measurement of the top quark mass uses single lepton events, giving the result m(top) = 173.3 +/- 5.6(stat.) +/- 6.2(syst.) GeV/c(2). The measurement of the t (t) over bar production cross section includes analyses from 8 top decay channels: dilepton (t (t) over bar --> e mu, ee, and mu mu), electron and neutrino (t (t) over bar --> ev), and single leptons (t (t) over bar --> e + jets and t (t) over bar --> mu + jets) with and without b tagging. We measure the t (t) over bar production cross section to be 5.5 +/- 1.8 pb at m(top) 173.3 GeV/c(2). C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Li, QZ (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JUN PY 1998 VL 65 BP 266 EP 271 DI 10.1016/S0920-5632(97)01012-8 PG 6 WC Physics, Particles & Fields SC Physics GA ZG234 UT WOS:000072980600045 ER PT J AU Staples, P Morley, K AF Staples, P Morley, K TI Neutron-induced fission cross-section ratios for Pu-239, Pu-240, Pu-242, and Pu-244 relative to U-235 from 0.5 to 400 MeV SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article AB The fission cross-section ratios for isotopic targets of Pu-240, Pu-242, and Pu-244 relative to U-235 are measured for neutron energies from 0.5 to 400 MeV and for Pu-239 relative to U-235 for energies from 0.85 to 62 MeV. A multiple-plate gas ionization detector was used to measure simultaneously the fission rate for each of the isotopic targets. The neutron energies were determined by the time-of-flight technique on a 20-m flight path at the Weapons Neutron Research white neutron source at the Las Alamos National Laboratory Neutron Science Center. Uncertainties are <4% for energies <50 MeV. This measurement provides the capability to resolve discrepancies among previous measurements for these isotopes over this energy range and are the first measurements for mast of these isotopes for energies >30 MeV. The results are compared with previous measurements and to ENDF/B-VI. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Staples, P (reprint author), Univ Calif Los Alamos Natl Lab, NIS-5,MS E540, Los Alamos, NM 87545 USA. NR 36 TC 22 Z9 22 U1 0 U2 1 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 JUN PY 1998 VL 129 IS 2 BP 149 EP 163 PG 15 WC Nuclear Science & Technology SC Nuclear Science & Technology GA ZU723 UT WOS:000074228000003 ER PT J AU Zucker, MS Tsoupas, N Vanier, PE von Wimmersperg, U Mughabghab, SF Schmidt, E AF Zucker, MS Tsoupas, N Vanier, PE von Wimmersperg, U Mughabghab, SF Schmidt, E TI Spallation neutron production measurements SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article AB Measurements of neutron production by the proton bombardment of range-thick targets of Pb and of W at energies of 0.8, 1.0, 1.2, and 1.4 GeV are made for comparison with calculations based on the LAHET code system (LAHET + MCNP) and also with each of two previous experiments. The code estimate of tritium production in the apparatus via the n(He-3,t)p reaction is also compared with the present measurements. C1 Brookhaven Natl Lab, Dept Adv Technol, Upton, NY 11973 USA. RP Zucker, MS (reprint author), Brookhaven Natl Lab, Dept Adv Technol, Mail Stop T-475C, Upton, NY 11973 USA. NR 7 TC 14 Z9 14 U1 0 U2 1 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 JUN PY 1998 VL 129 IS 2 BP 180 EP 186 PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA ZU723 UT WOS:000074228000006 ER PT J AU Sanchez, R Myers, W Hayes, D Kimpland, R Jaegers, P Paternoster, R Rojas, S Anderson, R Stratton, W AF Sanchez, R Myers, W Hayes, D Kimpland, R Jaegers, P Paternoster, R Rojas, S Anderson, R Stratton, W TI Criticality characteristics of mixtures of plutonium, silicon dioxide, Nevada tuff, and water SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article AB The parameters that determine when critical mixtures of Pu-239, SiO2, and water and mixtures of Pu-239, Nevada tuff, and water are capable of sustaining an increasing neutron chain reaction as may be caused by a positive void coefficient at constant temperature are established. A single canister is considered that is loaded with up to 75 kg of Pu-239. A survey of critical spherical mixtures of plutonium, SiO2, tuff, and water at constant temperature is created and these results are examined to determine the mixtures that might be autocatalytic. Regions of criticality instability are identified that have the possibility of autocatalytic power behavior. A positive void coefficient is possible for a very limited range of wet systems. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87544 USA. RP Sanchez, R (reprint author), Univ Calif Los Alamos Natl Lab, MS-J562, Los Alamos, NM 87544 USA. NR 13 TC 1 Z9 1 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 JUN PY 1998 VL 129 IS 2 BP 187 EP 194 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA ZU723 UT WOS:000074228000007 ER PT J AU Booth, TE AF Booth, TE TI Simultaneous Monte Carlo zero-variance estimates of several correlated means SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article ID BIASING SCHEMES AB Zero-variance biasing procedures are normally associated with estimating a single mean or "tally." In particular a zero-variance solution occurs when every sampling is made proportional to the product of the true probability multiplied by the expected score (importance) subsequent to the sampling; i.e., the zero-variance sampling is importance weighted. Because every tally has a different importance function, a zero-variance biasing for one tally cannot be a zero-variance biasing far another tally (unless the tallies are perfectly correlated). The way to optimize the situation when the required tallies have positive correlation is shown. C1 Univ Calif Los Alamos Natl Lab, Transport Methods Grp, XTM, Los Alamos, NM 87545 USA. RP Booth, TE (reprint author), Univ Calif Los Alamos Natl Lab, Transport Methods Grp, XTM, Mail Stop B226, Los Alamos, NM 87545 USA. NR 9 TC 1 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 0029-5639 J9 NUCL SCI ENG JI Nucl. Sci. Eng. PD JUN PY 1998 VL 129 IS 2 BP 199 EP 202 PG 4 WC Nuclear Science & Technology SC Nuclear Science & Technology GA ZU723 UT WOS:000074228000009 ER PT J AU Mueller, CJ Folga, SM Roglans-Ribas, J Nabelssi, B Mishima, J AF Mueller, CJ Folga, SM Roglans-Ribas, J Nabelssi, B Mishima, J TI A structured methodology for waste management facility accident analysis SO NUCLEAR TECHNOLOGY LA English DT Article DE risk analysis; environmental impact statements; waste management AB Guidance from the U.S. Department of Energy (DOE) for the performance of accident analysis in support of environmental impact assessments calls for a graded approach that considers frequencies as well as consequences of accidents, focuses on high-risk scenarios, and avoids bounding analyses that can obfuscate comparisons of alternative actions. This guidance reflects the fact that at the heart of an environmental impact statement is a comparative analysis of alternatives, including the proposed action; this analysis should address the environmental impacts in proportion to their potential significance, avoid addressing insignificant impacts in detail, and focus analysis resources to be as cost-effective as possible. Accordingly, a probabilistic risk analysis-based methodology to satisfy DOE guidance was developed and implemented for the DOE Waste Management Programmatic Environmental Impact Statement (WM PEIS). The methods are described and illustrated, and an outline of the computational framework is presented. This methodology, although developed for the WM PEIS, is, of course, applicable to general safety analyses. The implementation of the methods for the WM PEIS is summarized, and the extension of the methods to site-specific applications is explained. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Sci Applicat Int Corp, Richland, WA USA. RP Mueller, CJ (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 20 TC 0 Z9 0 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD JUN PY 1998 VL 122 IS 3 BP 306 EP 317 PG 12 WC Nuclear Science & Technology SC Nuclear Science & Technology GA ZT951 UT WOS:000074144800006 ER PT J AU Van Tuyle, GJ AF Van Tuyle, GJ TI Nuclear applications of accelerator-driven spallation targets SO NUCLEAR TECHNOLOGY LA English DT Article DE accelerator driven; nuclear applications; spallation targets ID TRANSMUTATION AB As a result of advances in particle accelerator technology and difficulties in building new nuclear reactors, increasingly ambitious applications of particle accelerator-driven spallation targets have been proposed in recent years. The simplest applications are the spallation neutron sources needed for basic nuclear sciences, with proton beams in the 1- to 5-MW range to be driven into targets of lead, mercury, or tungsten to produce neutron fluxes higher than is practical with nuclear reactors. On a much larger scale, the proposed accelerator production of tritium would use a 170-MW proton beam to generate sufficient neutrons to produce similar to 3 kg tritium/yr, based on neutron capture in a He-3 feedstock. Other proposals include the use of subcritical neutron multiplication, using waste actinides and/or fertile actinides to transmute nuclear wastes or support alternate fuel cycles. The basic technology and technical aspects of the numerous-proposed applications are described. Fundamental relationships regarding machine efficiencies, neutron production, and subcritical multiplication are provided and utilized to cross-compare concepts. C1 Assoc Univ Inc, Brookhaven Natl Lab, Dept Adv Technol, Upton, NY 11973 USA. RP Van Tuyle, GJ (reprint author), Assoc Univ Inc, Brookhaven Natl Lab, Dept Adv Technol, Bldg 701,POB 5000, Upton, NY 11973 USA. EM vantuyle@lanl.gov NR 39 TC 4 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 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD JUN PY 1998 VL 122 IS 3 BP 330 EP 354 PG 25 WC Nuclear Science & Technology SC Nuclear Science & Technology GA ZT951 UT WOS:000074144800008 ER PT J AU Erzberger, JP Barsky, D Scharer, OD Colvin, ME Wilson, DM AF Erzberger, JP Barsky, D Scharer, OD Colvin, ME Wilson, DM TI Elements in abasic site recognition by the major human and Escherichia coli apurinic/apyrimidinic endonucleases SO NUCLEIC ACIDS RESEARCH LA English DT Article ID DNA-REPAIR ENZYME; CONTAINING DEOXYTRIDECANUCLEOTIDE DUPLEXES; BASE EXCISION-REPAIR; HUMAN APURINIC ENDONUCLEASE; EXTRA ADENOSINE STACKS; EXONUCLEASE-III; POLYMERASE-BETA; CONFORMATIONAL TRANSITIONS; FLANKING SEQUENCE; BOVINE TESTIS AB Sites of base loss in DNA arise spontaneously, are induced by damaging agents or are generated by DNA glycosylases. Repair of these potentially mutagenic or lethal lesions is carried out by apurinic/apyrimidinic (AP) endonucleases. To test current models of AP site recognition, we examined the effects of site-specific DNA structural modifications and an F266A mutation on incision and protein-DNA complex formation by the major human AP endonuclease, Ape, Changing the ring component of the abasic site from a neutral tetrahydrofuran (F) to a positively charged pyrrolidine had only a 4-fold effect on the binding capacity of Ape, A non-polar 4-methylindole base analog opposite F had a <2-fold effect on the incision activity of Ape and the human protein was unable to incise or specifically bind 'bulged' DNA substrates. Mutant Ape F266A protein complexed with F-containing DNA with only a 6-fold reduced affinity relative to wild-type protein, Similar studies are described using Escherichia coli AP endonucleases, exonuclease III and endonuclease IV, The results, in combination with previous findings, indicate that the ring structure of an AP site, the base opposite an AP site, the conformation of AP-DNA pries to protein binding and the F266 residue of Ape are not critical elements in targeted recognition by AP endonucleases. C1 Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94551 USA. Harvard Univ, Dept Chem & Biol Chem, Cambridge, MA 02138 USA. RP Wilson, DM (reprint author), Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, L-452, Livermore, CA 94551 USA. EM wilson61@llnl.gov RI Scharer, Orlando/B-8908-2008 OI Scharer, Orlando/0000-0003-2425-2715 FU NCI NIH HHS [CA79056]; PHS HHS [51330] NR 62 TC 82 Z9 86 U1 0 U2 3 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0305-1048 J9 NUCLEIC ACIDS RES JI Nucleic Acids Res. PD JUN 1 PY 1998 VL 26 IS 11 BP 2771 EP 2778 DI 10.1093/nar/26.11.2771 PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA ZU005 UT WOS:000074151700037 PM 9592167 ER PT J AU Buchko, GW Ni, SS Thrall, BD Kennedy, MA AF Buchko, GW Ni, SS Thrall, BD Kennedy, MA TI Structural features of the minimal DNA binding domain (M98-F219) of human nucleotide excision repair protein XPA SO NUCLEIC ACIDS RESEARCH LA English DT Article ID A COMPLEMENTING PROTEIN; PIGMENTOSUM GROUP-C; XERODERMA-PIGMENTOSUM; TRANSCRIPTION FACTOR; ESCHERICHIA-COLI; ZINC FINGERS; DAMAGED DNA; IMPROVED SENSITIVITY; PYROCOCCUS-FURIOSUS; NMR-SPECTROSCOPY AB XPA, an essential protein in nucleotide excision repair (NER), interacts with damaged DNA and other proteins (RPA, ERCC1 and TFIIH) to remove a wide variety of chemically and structurally distinct DNA lesions from the eukaryotic genome. To understand the structural basis for the role of XPA in the repair process, the structure of the minimal DNA binding domain of human XPA [XPA-MBD (M98-F219)] was studied by NMR spectroscopy, A three-dimensional structure for XPA-MBD was generated using distance geometry and simulated annealing methods from NOB-based distance restraints, hydrogen bond and Zn-S distance restraints, and dihedral restraints. The structure calculations indicate that XPA-MBD contains elements of well-defined secondary structure interspaced with disordered loops organized into two non-interactive sub-domains: a zinc-binding core (D101-K137) and a loop-rich domain (L138-F219). The zinc-associated core contains an antiparallel beta-sheet (Y102-C105 and K110-M113) and an alpha-helix (C126-K137) separated by a poorly defined turn, reminiscent of the structure of the zinc-binding domain of the chicken erythroid transcription factor GATA-1 when bound to its cognate DNA sequence. The loop rich domain contains a triple-strand antiparallel P-sheet (L138-T140, L182-M178 and K163-K167), three loops (K151-L162, N169-D177 and Q208-F219) and three alpha-helices (K141-L150, K183-W194 and Q197-R207). The XPA-MBD structure is discussed in terms of known functions: binding single- and double-stranded DNA and binding RPA. C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Pacific NW Lab, Dept Mol Biosci, Richland, WA 99352 USA. RP Kennedy, MA (reprint author), Pacific NW Lab, Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. EM ma_kennedy@pnl.gov RI Buchko, Garry/G-6173-2015 OI Buchko, Garry/0000-0002-3639-1061 NR 67 TC 56 Z9 58 U1 0 U2 1 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0305-1048 J9 NUCLEIC ACIDS RES JI Nucleic Acids Res. PD JUN 1 PY 1998 VL 26 IS 11 BP 2779 EP 2788 DI 10.1093/nar/26.11.2779 PG 10 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA ZU005 UT WOS:000074151700038 PM 9592168 ER PT J AU Macchiavelli, AO AF Macchiavelli, AO TI Physics with gammasphere SO NUOVO CIMENTO DELLA SOCIETA ITALIANA DI FISICA A-NUCLEI PARTICLES AND FIELDS LA English DT Article; Proceedings Paper CT XVI Nuclear Physics Divisional Conference on Structure of Nuclei Under Extreme Conditions (SNEC 98) CY MAR 31-APR 04, 1998 CL PADUA, ITALY ID SUPERDEFORMED BAND; EXCITATION-ENERGIES; MASS REGION; SPIN; PARITY; HG-194; NUCLEI AB The technical properties of the GAMMASPHERE array are reviewed. A list of physics topics that have been studied with GAMMASPHERE stand-alone or in combination with auxiliary devices is presented. A few highlights are discussed and they include: i) the observation of superdeformation in mass 60, ii) one-step links in the superdeformed bands in Hg-194 and iii) the cosmic-ray chronometer Mn-54. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 20 TC 1 Z9 1 U1 0 U2 0 PU EDITRICE COMPOSITORI BOLOGNA PI BOLOGNA PA VIA STALINGRADO 97/2, I-40128 BOLOGNA, ITALY SN 1124-1861 J9 NUOVO CIMENTO A JI Nuovo Cimento Soc. Ital. Fis. A-Nucl. Part. Fields PD JUN-JUL PY 1998 VL 111 IS 6-7 BP 589 EP 599 PG 11 WC Physics, Particles & Fields SC Physics GA 165DP UT WOS:000078504700002 ER PT J AU Hamilton, JH Jones, EF Gore, PM Ramayya, AV Dodder, RS Beyer, CJ Hwang, JK Zhang, XQ Zhu, SJ de Lima, AP Kormicki, J Cole, JD Aryaeinejad, R Ma, WC Ter-Akopian, GM Oganessian, YT Daniel, AV Rasmussen, JO Asztalos, SJ Lee, IY Macchiavelli, AO Stoyer, MA Lougheed, RW Prussin, SG Donangelo, R AF Hamilton, JH Jones, EF Gore, PM Ramayya, AV Dodder, RS Beyer, CJ Hwang, JK Zhang, XQ Zhu, SJ de Lima, AP Kormicki, J Cole, JD Aryaeinejad, R Ma, WC Ter-Akopian, GM Oganessian, YT Daniel, AV Rasmussen, JO Asztalos, SJ Lee, IY Macchiavelli, AO Stoyer, MA Lougheed, RW Prussin, SG Donangelo, R TI A new phenomenon - shifted identical bands and new region of stable octupole deformation SO NUOVO CIMENTO DELLA SOCIETA ITALIANA DI FISICA A-NUCLEI PARTICLES AND FIELDS LA English DT Article; Proceedings Paper CT XVI Nuclear Physics Divisional Conference on Structure of Nuclei Under Extreme Conditions (SNEC 98) CY MAR 31-APR 04, 1998 CL PADUA, ITALY ID IDENTIFICATION; NUCLEI AB From gamma-gamma-gamma coincidence measurements in the spontaneous fission of Cf-252, level energies were established for spins 14(+) to 20(+) in many neutron-rich nuclei. New isotopes Sm-160 and Gd-162 were identified. The yrast bands of Nd-152,Nd-154,Nd-156, Sm-156,Sm-158,Sm-160, and Gd-160,Gd-162 exhibit remarkably near-identical transition energies and moments of inertia which are shifted by the same constant amounts for every spin state from 2(+) to 12(+) or 14(+) for nuclei differing by 2n, 4n, 2p, 4p, alpha, alpha+2p, and alpha+2n. These shifted identical bands (SIB) are a new phenomenon. Analysis of all known even-even proton to neutron-rich nuclei hom Ba (Z = 56) to Os (Z = 76) reveal no SIE for proton-rich nuclei and only a few additional cases of SIE for the most neutron-rich pairs around N = 98-102 separated by 2n and 2p. The levels in Mo-107 were extended and levels in Mo-109 identified for the first time. Conversion coefficient measurements and level patterns help establish a new region of stable octupole deformation for Mo-107,Mo-109 with N = 85, 67, associated with the nu(d(5/2)-h(11/2)) orbitals. This is the first region based on only one pair of orbitals. C1 Vanderbilt Univ, Dept Phys, Nashville, TN 37235 USA. Tsinghua Univ, Dept Phys, Beijing 100084, Peoples R China. Oak Ridge Natl Lab, Joint Inst Heavy Ion Res, Oak Ridge, TN 37831 USA. Univ Coimbra, Dept Phys, P-3000 Coimbra, Portugal. Idaho Natl Lab, Idaho Falls, ID 83415 USA. Mississippi State Univ, Dept Phys, Mississippi State, MS 39762 USA. Joint Inst Nucl Res, Dubna 141980, Russia. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Berkeley, Dept Nucl Engn, Berkeley, CA 94720 USA. Univ Fed Rio de Janeiro, Dept Phys, Rio De Janeiro, Brazil. RP Vanderbilt Univ, Dept Phys, Nashville, TN 37235 USA. NR 10 TC 2 Z9 2 U1 0 U2 0 PU EDITRICE COMPOSITORI BOLOGNA PI BOLOGNA PA VIA STALINGRADO 97/2, I-40128 BOLOGNA, ITALY SN 1124-1861 J9 NUOVO CIMENTO A JI Nuovo Cimento Soc. Ital. Fis. A-Nucl. Part. Fields PD JUN-JUL PY 1998 VL 111 IS 6-7 BP 633 EP 643 PG 11 WC Physics, Particles & Fields SC Physics GA 165DP UT WOS:000078504700007 ER PT J AU Smith, BH Riedinger, LL Jin, HQ Reviol, W Satula, W Galindo-Uribarri, A Sarantites, DG Wilson, JN Mullins, SM LaFosse, D AF Smith, BH Riedinger, LL Jin, HQ Reviol, W Satula, W Galindo-Uribarri, A Sarantites, DG Wilson, JN Mullins, SM LaFosse, D TI Bands of enhanced deformation in light Pr nuclei SO NUOVO CIMENTO DELLA SOCIETA ITALIANA DI FISICA A-NUCLEI PARTICLES AND FIELDS LA English DT Article; Proceedings Paper CT XVI Nuclear Physics Divisional Conference on Structure of Nuclei Under Extreme Conditions (SNEC 98) CY MAR 31-APR 04, 1998 CL PADUA, ITALY ID SUPERDEFORMED BANDS AB Rotational bands based on the pi g(9/2) structure have been assigned for the first time in Pr-127 and Pr-128, through GAMMASPHERE measurements. This extends the region of these bands of enhanced deformation down to N = 68 and 69, the lightest Pr isotopes for which this structure has been observed. C1 Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Washington Univ, St Louis, MO 63130 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Australian Natl Univ, Canberra, ACT, Australia. SUNY Stony Brook, Dept Phys, Stony Brook, NY 11794 USA. RP Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. NR 12 TC 1 Z9 1 U1 0 U2 0 PU EDITRICE COMPOSITORI BOLOGNA PI BOLOGNA PA VIA STALINGRADO 97/2, I-40128 BOLOGNA, ITALY SN 1124-1861 J9 NUOVO CIMENTO A JI Nuovo Cimento Soc. Ital. Fis. A-Nucl. Part. Fields PD JUN-JUL PY 1998 VL 111 IS 6-7 BP 663 EP 668 PG 6 WC Physics, Particles & Fields SC Physics GA 165DP UT WOS:000078504700011 ER PT J AU Collins, B Wein, G AF Collins, B Wein, G TI Soil resource heterogeneity effects on early succession SO OIKOS LA English DT Article ID OLD-FIELD VEGETATION; PLANT COMMUNITY; NITROGEN; COMPETITION; AVAILABILITY; MECHANISMS; RESPONSES; GRADIENTS; DIVERSITY; GRASSLAND AB Heterogeneous soil resources may cause vegetation heterogeneity on abandoned fields and grasslands. We tested effects of resource enrichment and heterogeneity at scales from a single plant to small plot community on vegetation composition and rare of early succession on two fields. Enriched plots of three heterogeneity scales were established by fertilizing alternate trenched subplots. Unenriched plots were established with trenched but unfertilized subplots as controls for trenching heterogeneity. Vegetation was censused every other year for six pears. We asked if nutrient enrichment or heterogeneity affects vegetation diversity or rate of succession, and if resource effects change over time. Species richness was lower in fertilized plots on both fields. Species turnover reflected an early gain of species on one field and loss on the other. Turnover differed between enriched and unenriched plots, bur not over heterogeneity scales. Plot enrichment. but nor heterogeneity, influenced initial abundance and establishment of a dominant, Ambrosin trifida, on one field and the later dominant Solidago altissima on the other field. Ambrosia responses slowed, and Solidago responses increased, succession on enriched plots. There was a weak trend of increasing strength of soil resource effects over time in both fields. We found no strong evidence that vegetation tracks soil resource heterogeneity of the patch sizes, arrangement, and contrast tested. However, differential growth of the dominant species and richness of minor taxa between enriched and unenriched plots created vegetation heterogeneity on both fields through early succession. C1 Savannah River Ecol Lab, Aiken, SC 29802 USA. RP Collins, B (reprint author), Savannah River Ecol Lab, PO Drawer E, Aiken, SC 29802 USA. NR 38 TC 30 Z9 31 U1 0 U2 8 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0030-1299 J9 OIKOS JI Oikos PD JUN PY 1998 VL 82 IS 2 BP 238 EP 245 DI 10.2307/3546963 PG 8 WC Ecology SC Environmental Sciences & Ecology GA 101QB UT WOS:000074878700004 ER PT J AU Rodriguez, G Taylor, AJ AF Rodriguez, G Taylor, AJ TI Measurement of cross-phase modulation in optical materials through the direct measurement of the optical phase change SO OPTICS LETTERS LA English DT Article ID NONLINEAR REFRACTIVE-INDEX; PULSES; INTENSITY; N(2) AB We measure the cross-phase modulation (XPM) nonlinear indices of optical materials resulting from the interaction of an ultrashort pump pulse at 800 nm with a weak ultrashort probe pulse at 400 nm through the direct measurement of the optical phase change, using frequency-resolved optical gating. The materials studied include fused silica (SiO2), borosilicate glass (BK-7), beta-BBO, and KD*P. This method results in a XPM nonlinear index that is in agreement with calculations based on nonlinear indices fi om previous self-phase modulation measurements. (C) 1998 Optical Society of America. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Rodriguez, G (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, MS D429, Los Alamos, NM 87545 USA. RI Rodriguez, George/G-7571-2012 OI Rodriguez, George/0000-0002-6044-9462 NR 11 TC 15 Z9 16 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD JUN 1 PY 1998 VL 23 IS 11 BP 858 EP 860 DI 10.1364/OL.23.000858 PG 3 WC Optics SC Optics GA ZT288 UT WOS:000074069500015 PM 18087365 ER PT J AU Pint, BA AF Pint, BA TI The oxidation behavior of oxide-dispersed beta-NiAl: I. Short-term performance at 1200 degrees C SO OXIDATION OF METALS LA English DT Article DE beta-NiAl; alpha-Al2O3; reactive element effect; oxide dispersion; scale adhesion; scale morphology ID HIGH-TEMPERATURE OXIDATION; CR-AL ALLOYS; ALUMINA SCALES; REACTIVE ELEMENTS; GROWTH MECHANISMS; IMPLANTED YTTRIUM; CYCLIC OXIDATION; ION-IMPLANTATION; FECRAL ALLOYS; ADHERENCE AB Oxide dispersions were added to beta-NiAl alloys using a powder-metallurgy technique. During 20, 2-hr cycles at 1200 degrees C, scale adhesion of the external alpha-Al2O3 was improved by the addition of Y2O3 and ZrO2. Relative to an undoped, cast NiAl alloy, no improvement was observed for TiO2 and HfO2 additions and negative effects were observed for Al2O3 and La2O3 additions. The various cation additions also had differing effects on the scale morphology and isothermal growth rates at 1200 degrees C. The effect of the dopants added as oxide dispersions was compared to similar alloy additions of the dopants to beta-NiAl. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Pint, BA (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA. RI Pint, Bruce/A-8435-2008 OI Pint, Bruce/0000-0002-9165-3335 NR 73 TC 80 Z9 82 U1 1 U2 12 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0030-770X J9 OXID MET JI Oxid. Met. PD JUN PY 1998 VL 49 IS 5-6 BP 531 EP 559 DI 10.1023/A:1018894711276 PG 29 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA 107ET UT WOS:000075194600008 ER PT J AU Mirin, AA Shumaker, DE Wehner, MF AF Mirin, AA Shumaker, DE Wehner, MF TI Efficient filtering techniques for finite-difference atmospheric general circulation models on parallel processors SO PARALLEL COMPUTING LA English DT Article DE atmospheric general circulation model; domain decomposition; high-latitude filtering AB Finite-difference-based atmospheric general circulation models using latitude/longitude meshes typically invoke filtering to suppress numerical instabilities occurring near the poles. We present a more efficient methodology for performing this filtering on parallel processors. This involves redistribution of the computational workload among all available processing elements, along with either the invocation of fast Fourier transforms to replace the slower numerical convolutions, or the smoothing of the transfer functions to enable use of fewer terms in the convolution sum. Results are presented on contemporary parallel architectures such as the Cray-T3D. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Mirin, AA (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 13 TC 2 Z9 2 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 JUN PY 1998 VL 24 IS 5-6 BP 729 EP 740 DI 10.1016/S0167-8191(98)00012-X PG 12 WC Computer Science, Theory & Methods SC Computer Science GA ZY657 UT WOS:000074646100004 ER PT J AU Pierron, X De Graef, M Thompson, AW AF Pierron, X De Graef, M Thompson, AW TI On the effect of hydrogen on the microstructure of alpha(2)-Ti3Al+Nb alloys SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article ID TITANIUM-ALUMINIDE ALLOY; AL-NB ALLOYS; TI-24AL-15NB ALLOY; PHASE; TRANSFORMATIONS; BEHAVIOR; TI3AL AB Hydrogen has repeatedly been shown to have a detrimental effect on the mechanical properties of alpha(2)-Ti3Al titanium aluminides containing niobium. The loss of ductility and toughness observed in these alloys in the presence of hydrogen has previously been attributed to the precipitation of brittle hydrides in the alpha(2) phase. The present paper reports a transmission electron microscopy (TEM) and X-ray diffraction study of the effect of hydrogen on the microstructure of two Ti3Al + Nb alloys, Ti-25 at.% Al-10 at.% Nb-3 at.% V-1 at.% Mo,. also known as Super-alpha(2), and Ti-25.2 at.% Al-9.5 at.% Nb. We present evidence for an orthorhombic. hydrogen-stabilized phase labelled O-H, and none of the previously reported hydrides were observed in this study. The O-H phase can be obtained by a simple distortion of the alpha(2) basal plane, and the magnitude of this distortion increases with increasing hydrogen content, The O-H phase reversibly disappears after hydrogen outgassing in vacuum. The morphology of this hydrogen-induced orthorhombic phase in the alpha(2) grains is described using the phenomenological theory of martensitic transformations. The calculated O-H habit planes, as well as the calculated interfaces separating two neighbouring O-H precipitates, agree with TEM observations of the hydrogen-charged microstructures. The stress-free interfaces separating twin-related O-H variants are the (110)(OH) and (130)(OH) planes. A reversible distortion of the B2 phase is also identified, and the B2 lattice parameter increases with increasing hydrogen content. C1 Dartmouth Coll, Thayer Sch Engn, Hanover, NH 03755 USA. Carnegie Mellon Univ, Dept Mat Sci & Engn, Pittsburgh, PA 15213 USA. Lawrence Berkeley Lab, Dept Mat Sci, Berkeley, CA 94720 USA. RP Pierron, X (reprint author), Dartmouth Coll, Thayer Sch Engn, Hanover, NH 03755 USA. RI DeGraef, Marc/G-5827-2010 OI DeGraef, Marc/0000-0002-4721-6226 NR 28 TC 11 Z9 11 U1 0 U2 2 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0141-8610 J9 PHILOS MAG A JI Philos. Mag. A-Phys. Condens. Matter Struct. Defect Mech. Prop. PD JUN PY 1998 VL 77 IS 6 BP 1399 EP 1421 PG 23 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA ZR185 UT WOS:000073948800004 ER PT J AU Fisher, IR Islam, Z Panchula, AF Cheon, KO Kramer, MJ Canfield, PC Goldman, AI AF Fisher, IR Islam, Z Panchula, AF Cheon, KO Kramer, MJ Canfield, PC Goldman, AI TI Growth of large-grain R-Mg-Zn quasicrystals from the ternary melt (R = Y, Er, Ho, Dy, Tb) SO PHILOSOPHICAL MAGAZINE B-PHYSICS OF CONDENSED MATTER STATISTICAL MECHANICS ELECTRONIC OPTICAL AND MAGNETIC PROPERTIES LA English DT Article ID ICOSAHEDRAL QUASI-CRYSTALS; SPIN-GLASS BEHAVIOR; PHASES; ALLOYS AB The growth of large (up to 0.5 cm(3)), single-grain R-Mg-Zn quasicrystals (R = Y, Er, Ho, Dy and Tb) from a ternary melt is described in detail. The quasicrystals grown by this technique have a composition R8.7Mg34.6Zn56.8, are thermodynamically stable and have a dodecahedral morphology with clearly visible pentagonal facets. The quasicrystalline phase has been examined by X-ray diffaction, high-resolution transmission electron microscopy, elemental analysis and transport measurements. In addition, results are presented for a closely related ternary crystalline phase. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. RP Fisher, IR (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RI Canfield, Paul/H-2698-2014 NR 21 TC 93 Z9 94 U1 0 U2 9 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0141-8637 J9 PHILOS MAG B JI Philos. Mag. B-Phys. Condens. Matter Stat. Mech. Electron. Opt. Magn. Prop. PD JUN PY 1998 VL 77 IS 6 BP 1601 EP 1615 DI 10.1080/13642819808206407 PG 15 WC Materials Science, Multidisciplinary; Mechanics; Physics, Applied; Physics, Condensed Matter SC Materials Science; Mechanics; Physics GA ZR186 UT WOS:000073948900001 ER PT J AU Morgan, RM Ivanov, AG Priscu, JC Maxwell, DP Huner, NPA AF Morgan, RM Ivanov, AG Priscu, JC Maxwell, DP Huner, NPA TI Structure and composition of the photochemical apparatus of the Antarctic green alga, Chlamydomonas subcaudata SO PHOTOSYNTHESIS RESEARCH LA English DT Article DE Antarctic alga; Chlamydomonas; 77 K fluorescence; light harvesting; Photosystem I; psychrophile ID PHOTOSYSTEM STOICHIOMETRY; LOW-TEMPERATURE; HIGH LIGHT; INDUCED ACCUMULATION; CHROMATIC REGULATION; QUANTUM EFFICIENCY; ICE ALGAE; PHOTOSYNTHESIS; GROWTH; PHOTOADAPTATION AB The green alga, Chlamydomonas subcaudata, collected from a perennially ice-covered Antarctic lake, was able to grow at temperatures of 16 degrees C or lower, but not at temperatures of 20 degrees C or higher, which confirmed its psychrophilic nature. Low temperature (77 K) Chi a fluorescence emission spectra of whole cells of the mesophile, C. reinhardtii, indicated the presence of major emission bands at 681 and 709 nm associated with PS II and PS I, respectively. In contrast, emission spectra of whole cells of C, subcaudata exhibited major emission bands at 681 and 692 nm associated with PS II, but the absence of a major PS I emission band at 709 nm. These results for C. subcaudata were consistent with: (1) low ratio of Chi a/b (1.80); (2) low levels of PsaA/PsaB heterodimer as well as specific Lhca polypeptides as determined by immunoblotting, (3) decreased levels of the Chi-protein complexes CPI and LHC I associated with PS I, and (4) an increased stability of the oligomeric form of LHC II as assessed by non-denaturing gel electrophoresis in the psychrophile compared to the mesophile. Further more, immunoblotting indicated that the stoichiometry of PS LI:PS I:CF1 is significantly altered in C, subcaudata compared to the mesophile. Even though the psychrophile is adapted to growth at low irradiance, it retained the capacity to adjust the total xanthophyll cycle pool size as well as the epoxidation state of the xanthophyll cycle. Despite these differences, the psychrophile and mesophile exhibited comparable photosynthetic efficiency for O-2 evolution regardless of growth conditions. P-max for both Chlamydomonas species was similar only when grown under identical conditions. We suggest that these photosynthetic characteristics of the Antarctic psychrophile reflect the unusual light and low temperature regime to which it is adapted. C1 Univ Western Ontario, Dept Plant Sci, London, ON N6A 5B7, Canada. Montana State Univ, Dept Biol, Bozeman, MT 59717 USA. Michigan State Univ, DOE, Plant Res Lab, E Lansing, MI 48824 USA. RP Huner, NPA (reprint author), Univ Western Ontario, Dept Plant Sci, London, ON N6A 5B7, Canada. OI Ivanov, Alexander G./0000-0001-7100-9211 NR 36 TC 37 Z9 38 U1 0 U2 6 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0166-8595 J9 PHOTOSYNTH RES JI Photosynth. Res. PD JUN PY 1998 VL 56 IS 3 BP 303 EP 314 DI 10.1023/A:1006048519302 PG 12 WC Plant Sciences SC Plant Sciences GA 113HR UT WOS:000075545400006 ER PT J AU Felcher, GP Dozier, W Marwick, AD AF Felcher, GP Dozier, W Marwick, AD TI Hydrogen segregation at the Al/Si(111) interface SO PHYSICA B LA English DT Article; Proceedings Paper CT 5th International Conference on Surface X-Ray and Neutron Scattering (SXNS-5) CY JUL 13-17, 1997 CL ST CATHERINES COLL, OXFORD, ENGLAND HO ST CATHERINES COLL DE hydrogen in metals; neutron reflection; depth profile AB The density depth profile of hydrogen trapped at an epitaxial solid-solid interface has been measured by neutron reflection. The interface was between a Si(111) substrate and an epitaxial film of Al 1500 Angstrom thick, into which hydrogen was introduced by low-energy implantion. The measurements, carried out at room temperature, indicated that a total of 0.7 x 10(16) H atoms/cm(2) were trapped at the interface. This number corresponds approximately to one atomic layer of liquid hydrogen; however, hydrogen was found to be spread over a thickness of 60 Angstrom. Cooling the sample from room temperature to 220 K did not significantly alter the distribution of hydrogen trapped at the interface. (C) 1998 Published by Elsevier Science B.V. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. IBM Corp, Div Res, Yorktown Heights, NY 10598 USA. RP Felcher, GP (reprint author), Argonne Natl Lab, Div Mat Sci, Bldg 223-D-117,9700S Cass Ave, Argonne, IL 60439 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 0921-4526 J9 PHYSICA B JI Physica B PD JUN 1 PY 1998 VL 248 BP 90 EP 94 DI 10.1016/S0921-4526(98)00209-9 PG 5 WC Physics, Condensed Matter SC Physics GA ZZ546 UT WOS:000074740900017 ER PT J AU Hashizume, H Ishimatsu, N Sakata, O Iizuka, T Hosoito, N Namikawa, K Iwazumi, T Srajer, G Venkataraman, CT Lang, JC Nelson, CS Berman, LE AF Hashizume, H Ishimatsu, N Sakata, O Iizuka, T Hosoito, N Namikawa, K Iwazumi, T Srajer, G Venkataraman, CT Lang, JC Nelson, CS Berman, LE TI Resonant X-ray magnetic scattering from the twisted states of an Fe/Gd multilayer SO PHYSICA B LA English DT Article; Proceedings Paper CT 5th International Conference on Surface X-Ray and Neutron Scattering (SXNS-5) CY JUL 13-17, 1997 CL ST CATHERINES COLL, OXFORD, ENGLAND HO ST CATHERINES COLL DE resonant X-ray magnetic scattering; circular polarization; X-ray reflectivity; twisted magnetic structure; magnetic phase diagram ID PHASE-TRANSITIONS; GD/FE MULTILAYERS; SUPERLATTICES; FILMS AB Resonant X-ray magnetic scattering experiments have been conducted using circularly polarized light at the Gd L-3, edge on a Fe/Gd multilayer at 300, 150, 100 and 10 K. Specular reflectivity data collected with magnetic fields applied parallel and perpendicular to the plane of scattering confirm the Fe-aligned state at 300 K and twisted states at the low temperatures. At 300K, the Gd spins appear to be distributed with a nonuniform profile along the layer thickness direction. There are at least two distinct twisted states with different magnetic structures at 100 and 10K. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Tokyo Inst Technol, Mat & Struct Lab, Midori Ku, Yokohama, Kanagawa 2268503, Japan. Kyoto Univ, Inst Chem Res, Uji 611, Japan. Tokyo Gakugei Univ, Koganei, Tokyo 184, Japan. Inst Mat Struct Sci, Photon Factory, Tsukuba, Ibaraki 305, Japan. Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. RP Hashizume, H (reprint author), Tokyo Inst Technol, Mat & Struct Lab, Midori Ku, Yokohama, Kanagawa 2268503, Japan. RI SAKATA, Osami/H-2621-2011 NR 15 TC 8 Z9 8 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD JUN 1 PY 1998 VL 248 BP 133 EP 139 DI 10.1016/S0921-4526(98)00219-1 PG 7 WC Physics, Condensed Matter SC Physics GA ZZ546 UT WOS:000074740900025 ER PT J AU Schlomka, JP Press, W Fitzsimmons, MR Lutt, M Grigorov, I AF Schlomka, JP Press, W Fitzsimmons, MR Lutt, M Grigorov, I TI Structural and magnetic properties of ion beam sputtered NiMnSb films SO PHYSICA B LA English DT Article; Proceedings Paper CT 5th International Conference on Surface X-Ray and Neutron Scattering (SXNS-5) CY JUL 13-17, 1997 CL ST CATHERINES COLL, OXFORD, ENGLAND HO ST CATHERINES COLL DE thin films; X-ray reflectivity; magneto-resistance ID HALF-METALLIC FERROMAGNETS; MAGNETORESISTANCE AB In this work the structural and magnetic properties of NiMnSb (NMS)-films deposited at different temperatures were investigated to determine optimal sample preparation conditions. Films of NMS were sputtered from a composite target onto heated(150-300 degrees C) Si(100) and MgO(100) substrates. The crystal structure was characterized by high angle X-ray diffraction, and polycrystalline samples with the typical Cl-b, structure were found for higher deposition temperatures. The roughness of the growth surface was investigated by X-ray reflectivity and X-ray diffuse scattering measurements. It was found to range from 13 to 60 Angstrom depending on the deposition temperature. Magnetization measurements confirmed ferromagnetic layers with a strong dependence of the coercive held on the deposition temperature. The saturation moments were found to be affected by deposition temperature and in all cases less than 2.5 mu(B), per Mn-site. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Kiel, Inst Expt Phys, D-24098 Kiel, Germany. Univ Calif Los Alamos Natl Lab, Manuel Lujan Jr Neutron Scattering Ctr, Los Alamos, NM 87545 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RP Schlomka, JP (reprint author), Univ Kiel, Inst Expt Phys, Gutenbergstr 76-78, D-24098 Kiel, Germany. EM schlomka@physik.uni-kiel.de RI Lujan Center, LANL/G-4896-2012 NR 10 TC 5 Z9 5 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD JUN 1 PY 1998 VL 248 BP 140 EP 145 DI 10.1016/S0921-4526(98)00221-X PG 6 WC Physics, Condensed Matter SC Physics GA ZZ546 UT WOS:000074740900026 ER PT J AU Larese, JZ AF Larese, JZ TI Neutron scattering studies of the structure and dynamics of methane absorbed on MgO(100) surfaces SO PHYSICA B LA English DT Article; Proceedings Paper CT 5th International Conference on Surface X-Ray and Neutron Scattering (SXNS-5) CY JUL 13-17, 1997 CL ST CATHERINES COLL, OXFORD, ENGLAND HO ST CATHERINES COLL DE neutron scattering; methane; MgO ID GRAPHITE; ADSORPTION; MOLECULES; SYMMETRY; OXIDE; FILMS AB Although neutrons are not normally viewed as surface-sensitive probes, elastic and high-resolution inelastic neutron scattering (INS) techniques are surprisingly effective ways to investigate the structural and dynamical properties of films adsorbed on solid surfaces. In fact, in cases where the adsorption takes place on crystalline powder samples with large surface-to-volume ratios and with highly uniform surfaces, neutron data can yield remarkably detailed pictures of gas-solid interactions. As an illustration of the power of this approach we will describe here what has been learned with neutrons about the structure and rotational dynamics of methane films adsorbed on MgO(100) surfaces. Since the sensitivity of such investigations is largely determined by the quality of the adsorbates employed we will also briefly describe how the MgO powders used in these studies were prepared and characterized. Elastic neutron diffraction data show that at low temperatures solid methane films on MgO surfaces exhibit a layer-by-layer growth pattern essentially identical to the growth of the (100) face of the bulk solid. It is not possible, however, to determine from the diffraction data how the molecules are oriented relative to the MgO surface plane. Interestingly, questions relating to the orientational order of the molecules can be addressed by studying low-temperature rotational tunneling in monolayer methane films with high-resolution INS. Unlike the simple, two-line tunneling spectrum observed in bulk methane, the monolayer film produces a more structured spectrum which, when analyzed, is found to be only consistent with a dipod-down configuration of the molecules (C-2v axis normal to surface plane). We have been able to follow the evolution of the tunneling spectrum as the film builds progressively, layer-by-layer, from one-to-six layers. Strong indication of a crossover from 2D-3D behavior are seen. (C) 1998 Published by Elsevier Science B.V. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Larese, JZ (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. NR 20 TC 31 Z9 31 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD JUN 1 PY 1998 VL 248 BP 297 EP 303 DI 10.1016/S0921-4526(98)00253-1 PG 7 WC Physics, Condensed Matter SC Physics GA ZZ546 UT WOS:000074740900053 ER PT J AU Krist, T Klose, F Felcher, GP AF Krist, T Klose, F Felcher, GP TI A white beam neutron spin splitter SO PHYSICA B LA English DT Article; Proceedings Paper CT 5th International Conference on Surface X-Ray and Neutron Scattering (SXNS-5) CY JUL 13-17, 1997 CL ST CATHERINES COLL, OXFORD, ENGLAND HO ST CATHERINES COLL DE polarized neutrons; reflectometry; supermirror AB The polarization of a narrow, highly collimated polychromatic neutron beam is tested by a neutron spin splitter that permits the simultaneous measurement of both spin states. The device consists of a Si-Co0.11Fe0.89 supermirror, which totally reflects one spin state up to a momentum transfer q = 0.04 Angstrom(-1), whilst transmits neutrons of the opposite spin state. The supermirror is sandwiched between two thick silicon wafers and is magnetically saturated by a magnetic field of 400 Oe parallel to its surface. The neutron beam enters through the edge of one of the two silicon wafers, its spin components are split by the supermirror and exit from the opposite edges of the two silicon wafers and are recorded at different channels of a position-sensitive detector. The device is shown to have excellent efficiency over a bread range of wavelengths. (C) 1998 Published by Elsevier Science B.V. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Hahn Meitner Inst Kernforsch Berlin GmbH, D-14109 Berlin, Germany. RP Felcher, GP (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave,Bldg 223-D-117, Argonne, IL 60439 USA. NR 7 TC 7 Z9 7 U1 2 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD JUN 1 PY 1998 VL 248 BP 372 EP 376 DI 10.1016/S0921-4526(98)00267-1 PG 5 WC Physics, Condensed Matter SC Physics GA ZZ546 UT WOS:000074740900065 ER PT J AU Tolan, M Sinha, SK AF Tolan, M Sinha, SK TI X-ray scattering with partial coherent radiation: The exact relationship between "resolution" and "coherence" SO PHYSICA B LA English DT Article; Proceedings Paper CT 5th International Conference on Surface X-Ray and Neutron Scattering (SXNS-5) CY JUL 13-17, 1997 CL ST CATHERINES COLL, OXFORD, ENGLAND HO ST CATHERINES COLL DE partial coherent radiation; surface/interface scattering; Fresnel/Fraunhofer limits AB We discuss the scattering of X-rays by matter using the Huygens-Fresnel method for the particular case of scattering from surfaces and interfaces. We discuss the exact relationship between "coherence" and "instrumental resolution" effects in various regimes. The so-called "Fraunhofer" and "Fresnel" regimes are distinguished and it is shown that most X-ray experiments are performed in what we call the "extreme Fresnel" regime. For each of those regimes the so-called "incoherent" and "coherent" limits are discussed. We illustrate the results with explicit calculations for surface scattering from layered materials. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Kiel, Inst Phys Expt, D-24098 Kiel, Germany. Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RP Tolan, M (reprint author), Univ Kiel, Inst Phys Expt, Leibnizstr 19, D-24098 Kiel, Germany. NR 7 TC 12 Z9 13 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD JUN 1 PY 1998 VL 248 BP 399 EP 404 DI 10.1016/S0921-4526(98)00271-3 PG 6 WC Physics, Condensed Matter SC Physics GA ZZ546 UT WOS:000074740900070 ER PT J AU Yaguchi, H Harrison, N Honold, MM Mielke, C Singleton, J Gee, PJ Rickel, D Deckers, I Reinders, PHP Herlach, F Kurmoo, M Day, P AF Yaguchi, H Harrison, N Honold, MM Mielke, C Singleton, J Gee, PJ Rickel, D Deckers, I Reinders, PHP Herlach, F Kurmoo, M Day, P TI The quantum Hall effect and chiral Fermi liquids in a quasi-two-dimensional organic conductor at very high magnetic fields SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 12th International Conference on Electronic Properties of 2-Dimensional Systems CY SEP 22-26, 1997 CL TOKYO, JAPAN DE quantum Hall effect; organic conductors; magnetoresistance oscillation; chiral sheath current ID BREAKDOWN AB The oscillations in the longitudinal magnetoresistance of alpha-(BEDT-TTF)(2)KHg(SCN)(4) are shown to be strongly attenuated with decreasing temperature if the sample is in a state where it displays the quantum Hall effect. We provide evidence that this is a direct consequence of the existence of a chiral Fermi liquid on the surface of the sample. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Oxford, Dept Phys, Clarendon Lab, Oxford OX1 3PU, England. Los Alamos Natl Lab, Natl High Magnet Field Lab, Los Alamos, NM 87545 USA. Katholieke Univ Leuven, Vaste Stof Fys & Magnetisme Lab, B-3001 Heverlee, Belgium. UCL Royal Inst Great Britain, London W1X 4BS, England. RP Univ Oxford, Dept Phys, Clarendon Lab, Oxford OX1 3PU, England. EM j.singleton1@physics.oxford.ac.uk RI Mielke, Charles/S-6827-2016 OI Mielke, Charles/0000-0002-2096-5411 NR 15 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 EI 1873-2135 J9 PHYSICA B JI Physica B PD JUN PY 1998 VL 249 BP 75 EP 78 DI 10.1016/S0921-4526(98)00070-2 PG 4 WC Physics, Condensed Matter SC Physics GA 102HW UT WOS:000074919400017 ER PT J AU McCormick, KL Woodside, MT Huang, M McEuen, PL Duruoz, CI Harris, JS AF McCormick, KL Woodside, MT Huang, M McEuen, PL Duruoz, CI Harris, JS TI Scanned potential microscopy of a two-dimensional electron gas SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 12th International Conference on Electronic Properties of 2-Dimensional Systems CY SEP 22-26, 1997 CL TOKYO, JAPAN DE atomic force; quantum Hall effect; voltage microscopy ID ATOMIC FORCE MICROSCOPE; SEMICONDUCTOR NANOSTRUCTURES; QUANTUM AB The high sensitivity and spatial resolution of the atomic force microscope make it a powerful tool for measuring local properties of mesoscopic systems. We consider its application to mapping voltage distributions in two cases: a narrow constriction in a two-dimensional electron gas, and a current-carrying quantum Hall conductor. We demonstrate the ability to measure these distributions with sub-micron resolution and sub-millivolt precision. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Stanford Univ, Stanford, CA 94305 USA. RP Univ Calif Berkeley, MS 2-200, Berkeley, CA 94720 USA. EM kentm@physics.berkeley.edu NR 19 TC 6 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 EI 1873-2135 J9 PHYSICA B JI Physica B PD JUN PY 1998 VL 249 BP 79 EP 83 DI 10.1016/S0921-4526(98)00071-4 PG 5 WC Physics, Condensed Matter SC Physics GA 102HW UT WOS:000074919400018 ER PT J AU Cobden, DH Bockrath, M Chopra, NG Zettl, A McEuen, PL Rinzler, A Thess, A Smalley, RE AF Cobden, DH Bockrath, M Chopra, NG Zettl, A McEuen, PL Rinzler, A Thess, A Smalley, RE TI Transport spectroscopy of single-walled carbon nanotubes SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 12th International Conference on Electronic Properties of 2-Dimensional Systems CY SEP 22-26, 1997 CL TOKYO, JAPAN DE one-dimensional transport; carbon nanotubes ID TUBULES AB We have performed transport spectroscopy on individual ropes of single-walled carbon nanotubes. We find that the levels are Zeeman split in a magnetic field, with a g-factor of 2.04 +/- 0.05. The observed pattern of peak splittings indicates the parity of the number of electrons on the dot. In one device there are also signs of the presence of a second dot. We observe features which resemble anticrossings between quantum levels in the two dots, which may be formed from separate conducting nanotubes within the rope. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab MS 2 200, Berkeley, CA 94720 USA. Rice Univ, Ctr Nanoscale Sci & Technol, Rice Quantum Inst, Houston, TX 77251 USA. Rice Univ, Dept Chem, Houston, TX 77251 USA. Rice Univ, Dept Phys, Houston, TX 77251 USA. RP Cobden, DH (reprint author), Oersted Lab, Univ Pk 5, DK-2100 Copenhagen, Denmark. EM cobden@fys.ku.dk RI Zettl, Alex/O-4925-2016 OI Zettl, Alex/0000-0001-6330-136X NR 13 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 EI 1873-2135 J9 PHYSICA B JI Physica B PD JUN PY 1998 VL 249 BP 132 EP 135 DI 10.1016/S0921-4526(98)00083-0 PG 4 WC Physics, Condensed Matter SC Physics GA 102HW UT WOS:000074919400030 ER PT J AU Marinescu, DC Quinn, JJ Yi, KS AF Marinescu, DC Quinn, JJ Yi, KS TI Coupled spin and charge collective excitations in a spin-polarized electron gas SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 12th International Conference on Electronic Properties of 2-Dimensional Systems CY SEP 22-26, 1997 CL TOKYO, JAPAN DE local field corrections; quantum wells; collective excitations AB The charge and longitudinal spin responses induced in a spin-polarized quantum well by a weak electromagnetic field are investigated within the framework of the linear response theory. We evaluate the excitation frequencies for the intra-and inter-subband transitions of the collective charge and longitudinal spin density oscillations including many-body corrections beyond the random-phase approximation through the spin-dependent local field factors, G(sigma)(+/-) =(q, omega). An equation-of-motion method was used to obtain these corrections in the limit of long wavelengths, and the results are given in terms of the equilibrium pair correlation function. The finite degree of spin polarization is shown to introduce coupling between the charge and spin density modes, in contrast with the result for an unpolarized system. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Pusan Natl Univ, Dept Phys, Pusan 609735, South Korea. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. RP Yi, KS (reprint author), Pusan Natl Univ, Dept Phys, Pusan 609735, South Korea. EM ksyi@hyowon.cc.pusan.ac.kr NR 8 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 EI 1873-2135 J9 PHYSICA B JI Physica B PD JUN PY 1998 VL 249 BP 727 EP 730 DI 10.1016/S0921-4526(98)00301-9 PG 4 WC Physics, Condensed Matter SC Physics GA 102HW UT WOS:000074919400156 ER PT J AU Zeman, J Martinez, G Kwok, SH Yu, PY Uchida, K AF Zeman, J Martinez, G Kwok, SH Yu, PY Uchida, K TI Electron confinement in (ordered)GaInP2/GaAs/(ordered)GaInP2 single quantum well SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 12th International Conference on Electronic Properties of 2-Dimensional Systems CY SEP 22-26, 1997 CL TOKYO, JAPAN DE GaInP/GaAs quantum wells; magnetophotoluminescence; quantum wells ID ARBITRARY MAGNETIC-FIELDS; ENERGY-LEVELS; GAINP AB Quantum confinement of electrons in a series of undoped (ordered)GaInP2/GaAs/(ordered)GaInP2 single quantum well (QW) samples was studied by magnetophotoluminescence measurements. The electron confinement is observed only in the sample with two thin GaP barriers inserted on both sides of the GaAs QW. The excitonic photoluminescence peak related to the transition between confined electron and hole states does not exactly obey the B cos(Theta) law in the tilted magnetic field which is explained by the quasi-two-dimensional nature of electrons confined in the well by partially transmitting GaP barriers. (C) 1998 Elsevier Science B.V. All rights reserved. C1 CNRS, FKF, MPI, Grenoble High Magnet Field Lab, F-38042 Grenoble 09, France. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Electrocommun, Dept Commun & Syst, Chofu, Tokyo 182, Japan. RP Zeman, J (reprint author), CNRS, FKF, MPI, Grenoble High Magnet Field Lab, BP 166,25 Av Martyrs, F-38042 Grenoble 09, France. EM zeman@labs.polycnrs-gre.fr NR 10 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 EI 1873-2135 J9 PHYSICA B JI Physica B PD JUN PY 1998 VL 249 BP 735 EP 739 DI 10.1016/S0921-4526(98)00303-2 PG 5 WC Physics, Condensed Matter SC Physics GA 102HW UT WOS:000074919400158 ER PT J AU Simmons, JA Harff, NE Lyo, SK Boebinger, GS Klem, JF Pfeiffer, LN West, KW AF Simmons, JA Harff, NE Lyo, SK Boebinger, GS Klem, JF Pfeiffer, LN West, KW TI Magnetic breakdown and Landau level spectra of a tunable double-quantum-well Fermi surface SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 12th International Conference on Electronic Properties of 2-Dimensional Systems CY SEP 22-26, 1997 CL TOKYO, JAPAN DE double-quantum well; Fermi surface; magnetotransport; Landau level ID FIELDS; MASS AB By measuring longitudinal resistance, we map the Landau level spectra of double quantum wells as a function of both parallel (B-parallel to) and perpendicular (B-perpendicular to) magnetic fields. In this continuously tunable highly non-parabolic system, the cyclotron masses of the two Fermi surface orbits change in opposite directions with B-parallel to. This causes the two corresponding ladders of Landau levels formed at finite B-perpendicular to, to exhibit multiple crossings. We also observe a third set of Landau levels, independent of B-parallel to, which arise from magnetic breakdown of the Fermi surface. Both semiclassical and full-quantum mechanical calculations show good agreement with the data. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Lucent Technol, Bell Labs, Murray Hill, NJ 07974 USA. RP Simmons, JA (reprint author), Sandia Natl Labs, POB 5800,Mail Stop 1415, Albuquerque, NM 87185 USA. EM jsimmon@sandia.gov NR 8 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 EI 1873-2135 J9 PHYSICA B JI Physica B PD JUN PY 1998 VL 249 BP 845 EP 849 DI 10.1016/S0921-4526(98)00328-7 PG 5 WC Physics, Condensed Matter SC Physics GA 102HW UT WOS:000074919400183 ER PT J AU Zheng, H Jiang, M Veal, BW Claus, H Obst, B AF Zheng, H Jiang, M Veal, BW Claus, H Obst, B TI Growth rate dependence of physical properties of YBa2Cu3Ox single crystals SO PHYSICA C LA English DT Article DE growth rate; YBa2Cu3Ox single crystals; magnetization ID OXYGEN-DEFICIENT YBA2CU3O7-DELTA; T-C SUPERCONDUCTORS; MAGNETIZATION; DIFFRACTION; BAZRO3; PURE AB We present magnetization measurements on YBa2Cu3Ox single crystals cooled at various rates (0.1-1.0 degrees C/h) during the growth process. The oxygen concentration dependence of the superconducting transition temperature, T-c, as determined from the low-field magnetization, is very different for samples grown at different cooling rates. Crystals grown at 1.0 and 0.7 degrees C/h display the typical T-c vs. x maximum, with a maximum T-c of 93.4 K at an oxygen concentration of x = 6.94 (oxygenation at 480 degrees C in flowing O-2). Crystals grown at the rate of 0.3 degrees C/h show a similar maximum in T-c vs. x, but with a maximum value of T-c of only 92 K. Crystals grown at an even slower rate (0.2 and 0.1 degrees C/h) no longer display a maximum in T-c vs. x. For these crystals, T-c monotonically decreases with decreasing oxygen concentration. The maximum T-c of 91 K is reached at the lowest oxygenation temperature of 375 degrees C. This difference in T-c vs. oxygen concentration is accompanied by significant differences in the pinning behavior as determined from hysteresis loop measurements. The microscopic conditions giving rise to this behavior are not understood. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Univ Illinois, Dept Phys, Chicago, IL 60607 USA. Forschungszentrum Karlsruhe, Inst Tech Phys, D-76021 Karlsruhe, Germany. RP Claus, H (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 19 TC 9 Z9 9 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD JUN 1 PY 1998 VL 301 IS 3-4 BP 147 EP 154 DI 10.1016/S0921-4534(98)00153-1 PG 8 WC Physics, Applied SC Physics GA ZX444 UT WOS:000074516500004 ER PT J AU Zhang, XF Sung, YS Miller, DJ AF Zhang, XF Sung, YS Miller, DJ TI Special Tl-Ba-Ca-Cu-O structures: two intermediate states and their superconducting behavior SO PHYSICA C LA English DT Article DE Tl-Ba-Ca-Cu-O; structure; defect ID THALLIUM CUPRATE SUPERCONDUCTORS; THIN-FILMS; ELECTRON-MICROSCOPY; CRYSTAL-STRUCTURE; NEUTRON-DIFFRACTION; TL2BA2CA2CU3O10; TL2BA2CACU2O8; TLBA2CA2CU3O9; INTERGROWTH; DEFECTS AB Two special structures formed in Tl-Ba-Ca-Cu-O superconducting compounds are reported in this paper. The first one is a defective Tl2Ba2CaCu2Oy (Tl-2212) structure in which a large amount of Tl vacancies distribute unevenly in the (Tl-O), bilayers, This defective structure is considered corresponding to an early stage of the transition from the bilayered Tl-2212 structure to monolayered Tl-1212 (TlBa2CaCu2Oy) structure, therefore can be considered as an intermediate state between the ideal Tl-2212 and Tl-1212 structures. The second special structure is formed by ordered intergrowths along the c-axis between Tl-O monolayered structures and (Tl-O), bilayered structures. Phases formed by such superlattices possess their own structural and superconductive characteristics which define the phases as another type of intermediate state between the ideal Tl-Ba-Ca-Cu-O structures. Both types of intermediate structures are found closely related to the nonstoichiometric Tl concentration. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Sci & Technol Ctr Superconduct, Argonne, IL 60439 USA. RP Zhang, XF (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Mail Stop K765, Los Alamos, NM 87545 USA. NR 38 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 JUN 1 PY 1998 VL 301 IS 3-4 BP 221 EP 233 DI 10.1016/S0921-4534(98)00150-6 PG 13 WC Physics, Applied SC Physics GA ZX444 UT WOS:000074516500013 ER PT J AU Aharonov, Y Oppenheim, J Popescu, S Reznik, B Unruh, WG AF Aharonov, Y Oppenheim, J Popescu, S Reznik, B Unruh, WG TI Measurement of time of arrival in quantum mechanics SO PHYSICAL REVIEW A LA English DT Article AB It is argued that the time of arrival cannot be precisely defined and measured in quantum mechanics. By constructing explicit toy models of a measurement, we show that for a free particle it cannot be measured more accurately then Delta t(A) similar to 1/E-k, where E-k is the initial kinetic energy of the particle. With a better accuracy, particles reflect off the measuring device, and the resulting probability distribution becomes distorted. It is shown that: a time-of-arrival operator cannot exist, and that approximate time-of-arrival operators do not correspond to the measurements considered here. C1 Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Univ S Carolina, Dept Phys, Columbia, SC 29208 USA. Univ British Columbia, Dept Phys, Vancouver, BC V6T 1Z1, Canada. Univ Cambridge, Isaac Newton Inst, Cambridge CB3 0HE, England. Hewlett Packard Labs, BRIMS, Bristol BS12 6QZ, Avon, England. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Aharonov, Y (reprint author), Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. NR 16 TC 90 Z9 91 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUN PY 1998 VL 57 IS 6 BP 4130 EP 4139 DI 10.1103/PhysRevA.57.4130 PG 10 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA ZU090 UT WOS:000074160600014 ER PT J AU Weinberg, G Beck, BR Steiger, J Church, DA McDonald, J Schneider, D AF Weinberg, G Beck, BR Steiger, J Church, DA McDonald, J Schneider, D TI Electron capture from H-2 to highly charged Th and Xe ions trapped at center-of-mass energies near 6 eV SO PHYSICAL REVIEW A LA English DT Article ID CROSS-SECTIONS; 2-ELECTRON TRANSFER; MERGED-BEAMS; COLLISIONS; SLOW; AR; ATOMS; HE; TRANSITIONS; PARTICLE AB Ions with charge states as high as 80+, produced in the Lawrence Livermore National Laboratory electron beam ion trap were extracted and transferred to a Penning ion trap (RETRAP). RETRAP was operated at cryogenic temperature in the field of a superconducting magnet. The stored low-energy ions collided occasionally with H-2 molecules in the ultrahigh-vacuum environment of the trap, capturing one or two electrons and reducing the charge state of the ions. The number of ions was monitored nondestructively by ramping the axial oscillation frequencies of the ions through resonance with a tuned circuit composed in part of trap capacitance and an external inductor. This produced resonance signals whose square is proportional to the number of ions in each charge state. These signals were recorded vs storage time to determine the electron-capture rates. From these rates the relative electron-capture cross sections were obtained using estimates of the mean ion energies based on modeling the ion storage, and with the aid of a density calibration measurement using Ar11+. The measured total electron-capture cross sections are consistent with a linear increase with charge state q. The cross-section data for the highest charge states lie above the predictions of the absorbing sphere model, but agree within uncertainties in both experiment and theory. The true double-capture cross-section fraction for q>35 is near 25%. The results are discussed with relation to measurements on lower charge states, and with theory. C1 Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Weinberg, G (reprint author), 2201 3rd St, San Francisco, CA USA. NR 33 TC 11 Z9 11 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUN PY 1998 VL 57 IS 6 BP 4452 EP 4461 DI 10.1103/PhysRevA.57.4452 PG 10 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA ZU090 UT WOS:000074160600052 ER PT J AU Gaarde, MB Antoine, P L'Huillier, A Schafer, KJ Kulander, KC AF Gaarde, MB Antoine, P L'Huillier, A Schafer, KJ Kulander, KC TI Macroscopic studies of short-pulse high-order harmonic generation using the time-dependent Schrodinger equation SO PHYSICAL REVIEW A LA English DT Article ID LASER; IONIZATION; GASES AB We consider high harmonic generation by ultrashort (27-108 fs) laser pulses and calculate the macroscopic response of a collection of atoms to such a short pulse. We show how the harmonic spectrum after propagation through the medium is significantly different from the single-atom spectrum. We use single-atom data calculated by integration of the time-dependent Schrodinger equation and propose a method, based on an adiabatic approximation;:to extract the data necessary to perform a propagation calculation. C1 Lund Inst Technol, Dept Phys, S-22100 Lund, Sweden. Niels Bohr Inst, Orsted Lab, DK-2100 Kbh O, Denmark. Univ Catholique Louvain, Lab Phys Atom & Mol, B-1348 Louvain, Belgium. Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA. Univ Calif Lawrence Livermore Natl Lab, TAMP Grp, Livermore, CA 94551 USA. RP Gaarde, MB (reprint author), Lund Inst Technol, Dept Phys, POB 118, S-22100 Lund, Sweden. RI L'Huillier, Anne/P-4379-2015 OI L'Huillier, Anne/0000-0002-1335-4022 NR 21 TC 49 Z9 50 U1 1 U2 7 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUN PY 1998 VL 57 IS 6 BP 4553 EP 4560 DI 10.1103/PhysRevA.57.4553 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA ZU090 UT WOS:000074160600064 ER PT J AU Cohen, JS AF Cohen, JS TI Extension of quasiclassical effective Hamiltonian structure of atoms through Z = 94 SO PHYSICAL REVIEW A LA English DT Article ID IONIZATION; COLLISIONS; HEISENBERG; HELIUM AB The ground states of all atoms (through Z = 94) and their first and second ions have been calculated using the Kirschbaum-Wilets (KW) quasiclassical, many-body atomic model [Phys. Rev. A 21, 834 (1980)]. The present calculations allow the atoms to be in any spin state. The results essentially agree with previous calculations, done for atoms and their first ions with Z = 1 to 38 [Phys. Rev. A 51, 266 (1995)], which constrained the atoms to minimal-total-spin configurations (S=O or 1/2). The KW model is shown to be similarly valid for the heavier atoms. However, it is found that a number of the heavier atoms and ions have KW ground states-with nonminimal total spins (S = 1 or 3/2). C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Cohen, JS (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. EM cohen@lanl.gov NR 15 TC 16 Z9 16 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUN PY 1998 VL 57 IS 6 BP 4964 EP 4966 DI 10.1103/PhysRevA.57.4964 PG 3 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA ZU090 UT WOS:000074160600109 ER PT J AU Ditmire, T AF Ditmire, T TI Simulation of exploding clusters ionized by high-intensity femtosecond laser pulses SO PHYSICAL REVIEW A LA English DT Article ID INDUCED COULOMB EXPLOSION; X-RAY-EMISSION; IONIZATION AB The dynamics of small (less than or equal to 55 atom) argon clusters ionized by a high-intensity, femtosecond laser pulse have been studied using classical particle dynamics simulations. The evolution of both ions and electrons during the laser pulse is examined. These simulations show that the space-charge and impact ionization of electrons, liberated from individual atoms in the cluster, have a very important effect on the ion energies resulting from the cluster explosion. C1 Lawrence Livermore Natl Lab, Laser Program L440, Livermore, CA 94550 USA. RP Ditmire, T (reprint author), Lawrence Livermore Natl Lab, Laser Program L440, 7000 East Ave, Livermore, CA 94550 USA. NR 21 TC 72 Z9 73 U1 0 U2 9 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUN PY 1998 VL 57 IS 6 BP R4094 EP R4097 DI 10.1103/PhysRevA.57.R4094 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA ZU090 UT WOS:000074160600006 ER PT J AU Hansen, DL Armen, GB Arrasate, ME Cotter, J Fisher, GR Leung, KT Levin, JC Martin, R Neill, P Perera, RCC Sellin, IA Simon, M Uehara, Y Vanderford, B Whitfield, SB Lindle, DW AF Hansen, DL Armen, GB Arrasate, ME Cotter, J Fisher, GR Leung, KT Levin, JC Martin, R Neill, P Perera, RCC Sellin, IA Simon, M Uehara, Y Vanderford, B Whitfield, SB Lindle, DW TI Postcollision-interaction effects in HCl following photofragmentation near the chlorine K edge SO PHYSICAL REVIEW A LA English DT Article ID POST-COLLISION INTERACTION; INNER-SHELL PHOTOIONIZATION; SYNCHROTRON RADIATION BEAMLINE; HIGH-ENERGY-RESOLUTION; ADVANCED LIGHT-SOURCE; X-RAY SPECTROSCOPY; COINCIDENCE MEASUREMENTS; PHOTOELECTRON RECAPTURE; AUGER PROCESSES; DECAY AB Ion time-of-flight mass spectroscopy was used to study the relaxation dynamics of HCl following photoexcitation in the vicinity of the Cl K threshold (approximate to 2.8 keV). Detailed observations of molecular fragmentation mediated by postcollision interaction between a photoelectron and an Auger electron are presented, evidenced by the recapture of Cl K photoelectrons by either Cln+ or H+ dissociation fragments. C1 Univ Nevada, Dept Chem, Las Vegas, NV 89154 USA. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. Univ Nevada, Dept Phys, Reno, NV 89557 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Waterloo, Dept Chem, Waterloo, ON N2L 3G1, Canada. Univ Paris Sud, LURE, F-91405 Orsay, France. CENS, CEA, SPAM, DRECAM, F-91191 Gif Sur Yvette, France. Mitsubishi Elect Corp, Amagasaki, Hyogo 661, Japan. Univ Wisconsin, Dept Phys & Astron, Eau Claire, WI 54702 USA. RP Hansen, DL (reprint author), Univ Nevada, Dept Chem, Las Vegas, NV 89154 USA. NR 28 TC 12 Z9 12 U1 0 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUN PY 1998 VL 57 IS 6 BP R4090 EP R4093 DI 10.1103/PhysRevA.57.R4090 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA ZU090 UT WOS:000074160600005 ER PT J AU Savoini, B Ballesteros, C Santiuste, JEM Gonzalez, R Chen, Y AF Savoini, B Ballesteros, C Santiuste, JEM Gonzalez, R Chen, Y TI Thermochemical reduction of yttria-stabilized-zirconia crystals: Optical and electron microscopy SO PHYSICAL REVIEW B LA English DT Article ID MAGNESIUM-OXIDE; SINGLE-CRYSTALS; COLLOIDS; PRECIPITATION; ABSORPTION AB Thermochemical reduction (TCR) at high temperatures has been performed on yttria-stabilized zirconia (YSZ), undoped and doped with Ni:Er, Co. or Pr. Investigations were carried out using optical absorption, luminescence, and analytical electron microscopy. After TCR, undoped crystals show an extinction band centered at about 1.8 eV which is attributed to Mie scattering from precipitates with an average size of 10 nm, as observed by analytical transmission electron microscopy. In crystals codoped with Ni:Er, TCR induced a broad extinction band centered at 1.3 eV beginning at 1600 K. Metallic Ni colloids contributing to Mie scattering have an average size of 100 nm. Similarly, in Go-doped crystals a broad band at 0.9 eV, emerging at 1750 K, was attributed to metallic colloids observed to have an average dimension of 200 nm. In all cases, the precipitate distribution is very inhomogeneous. These results agree qualitatively with the predictions of the Mie theory for the extinction bands associated with metal colloids embedded in the matrix. Electron microscope observations indicate that the degradation of the optical properties experienced by previously reduced YSZ crystals during oxidation at elevated temperatures is a bulk effect probably related to cavities and dislocations. C1 Univ Carlos Madrid 3, Escuela Politecn Super, E-28911 Madrid, Spain. US DOE, Off Basic Energy Sci, Div Sci Mat, Germantown, MD 20874 USA. RP Savoini, B (reprint author), Univ Carlos Madrid 3, Escuela Politecn Super, Butarque 15,Leganes, E-28911 Madrid, Spain. RI Munoz Santiuste, Juan/K-7461-2015; OI Munoz Santiuste, Juan/0000-0001-6286-139X; SAVOINI, BEGONA/0000-0002-7347-7569; BALLESTEROS, CARMEN INES/0000-0002-8983-4751 NR 28 TC 24 Z9 24 U1 0 U2 14 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUN 1 PY 1998 VL 57 IS 21 BP 13439 EP 13447 DI 10.1103/PhysRevB.57.13439 PG 9 WC Physics, Condensed Matter SC Physics GA ZT216 UT WOS:000074061700026 ER PT J AU Woodward, C Kajihara, S Yang, LH AF Woodward, C Kajihara, S Yang, LH TI Site preferences and formation energies of substitutional Si, Nb, Mo, Ta,and W solid solutions in L1(0) Ti-Al SO PHYSICAL REVIEW B LA English DT Article ID ELASTIC-CONSTANTS; AB-INITIO; 1ST-PRINCIPLES CALCULATION; TRANSITION-METALS; POINT-DEFECTS; GROUND-STATE; STRESS; PSEUDOPOTENTIALS; ALUMINUM; SYSTEMS AB Modifications to alloy chemistry are often used to tailor the intrinsic flow behavior of structural materials. Models of solution strengthening, high-temperature yield stress and creep must relate the effects of chemistry to the mechanisms which influence these material properties. In ordered alloys, additional information regarding the crystallographic site occupancy of substitutional solid solutions is required. The energy of intrinsic and substitutional point defects in L1(0) TiAl are calculated within a fil st principles, local density functional theory framework. We calculate the relaxed structures and energies of vacancies, antisites, and substitutional defects using a plane-wave pseudopotential method. The results of these total energy calculations are incorporated into a simple thermodynamic model in order to determine the density of point defects as a function of temperature and stoichiometry. Defect densities are presented as a function of alloy chemistry and temperature for binary TiAl and ternary additions (Si, Nb, Mo, Ta, and W). Defect formation energies are calculated using the derived chemical potentials of each atomic species for several alloy compositions. The predicted site selection of the solutes are in excellent agreement with recent x-ray emission experiments using a quantitative statistical method for atom location by channelling enhanced microanalysis. C1 USAF, Res Lab, Mat & Mfg Directorate, Wright Patterson AFB, OH 45433 USA. Univ Calif Lawrence Livermore Natl Lab, Phys Div H, Livermore, CA 94551 USA. Universal Energy Syst Inc, Mat Res Div, Dayton, OH 45432 USA. RP Woodward, C (reprint author), USAF, Res Lab, Mat & Mfg Directorate, Wright Patterson AFB, OH 45433 USA. NR 45 TC 55 Z9 57 U1 2 U2 10 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUN 1 PY 1998 VL 57 IS 21 BP 13459 EP 13470 DI 10.1103/PhysRevB.57.13459 PG 12 WC Physics, Condensed Matter SC Physics GA ZT216 UT WOS:000074061700028 ER PT J AU Bud'ko, SL Canfield, PC Mielke, CH Lacerda, AH AF Bud'ko, SL Canfield, PC Mielke, CH Lacerda, AH TI Anisotropic magnetic properties of light rare-earth diantimonides SO PHYSICAL REVIEW B LA English DT Article ID ANTIFERROMAGNETIC METALS; MAGNETORESISTANCE; SYSTEMS; GROWTH; FIELD AB Results are presented of anisotropic temperature and field-dependent magnetization M(H,T) and resistivity rho(H T) measurements on high quality single crystals of the light rare-earth diantimonides RSb2, R = La-Nd, Sm. All of these, excepting LaSb2, magnetically order at low temperatures, and for CeS2, and NdSb2 several magnetically ordered phases were observed in low-field magnetization and zero-field resistivity measurements. For R = Ce-Sm strong anisotropies, associated with crystalline electric field (CEF) splitting of the R3+ ion, were found in M(T) measurements both below and above magnetic ordering temperatures. Furthermore, for R = Ce-Nd metamagnetic transitions were observed in IM(H) and p(H) for H parallel to(ab) in the magnetically ordered state. In addition, above 15 kG de Haas-van Alphen oscillations are observed for SmSb2 and Shubnikov-de Haas quantum oscillations are observed above similar to 120 kG for NdSb2 and SmSb2. The zero-field in-plane resistivity rho(ab) of all of the compounds is metallic (d rho/dT>0), with residual resistance ratios ranging from 40 to 750. The c-axis resistivity is also metallic, but appears to be considerably larger than the in-plane value, consistent with the diantimonides being quasi-two-dimensional materials. The magnetoresistance of all members of the series is large, approximately Linear in H at moderate fields, and is also dependent on the relative orientation of the applied magnetic fields to the crystallographic axes. The extreme case of SmSb, has [rho(55 kG)-rho(0)]/rho(0)>50000% at T = 2 K and H parallel to c. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. Univ Calif Los Alamos Natl Lab, Los Alamos Facil, Natl High Magnet Field Lab, Los Alamos, NM 87545 USA. RP Bud'ko, SL (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RI Canfield, Paul/H-2698-2014; Mielke, Charles/S-6827-2016 OI Mielke, Charles/0000-0002-2096-5411 NR 42 TC 71 Z9 71 U1 2 U2 35 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 JUN 1 PY 1998 VL 57 IS 21 BP 13624 EP 13638 DI 10.1103/PhysRevB.57.13624 PG 15 WC Physics, Condensed Matter SC Physics GA ZT216 UT WOS:000074061700048 ER PT J AU Scheidl, S Vinokur, VM AF Scheidl, S Vinokur, VM TI Dynamic melting and decoupling of the vortex lattice in layered superconductors SO PHYSICAL REVIEW B LA English DT Article ID FLUX-LINE-LATTICE; HIGH-TEMPERATURE SUPERCONDUCTORS; HIGH-TC SUPERCONDUCTORS; CHARGE-DENSITY WAVES; PHASE-TRANSITIONS; THERMAL FLUCTUATIONS; QUENCHED DISORDER; SYMMETRY-BREAKING; ELASTIC THEORY; SYSTEMS AB The dynamic phase diagram of vortex lattices driven in disorder is calculated in two and three dimensions. A modified Lindemann criterion for the fluctuations of the distance of neighboring vortices is used, which unifies previous analytic approaches to the equilibrium and nonequilibrium phase transitions. The temperature shifts of the dynamic melting and decoupling transitions are found to scale inversely proportional to large driving currents. A comparison with two-dimensional simulations shows that this phenomenological approach can provide a quantitative estimate for the location of these transitions. C1 Univ Koln, Inst Theoret Phys, D-50937 Koln, Germany. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Scheidl, S (reprint author), Univ Koln, Inst Theoret Phys, Zulpicher Str 77, D-50937 Koln, Germany. NR 57 TC 40 Z9 40 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 JUN 1 PY 1998 VL 57 IS 21 BP 13800 EP 13810 DI 10.1103/PhysRevB.57.13800 PG 11 WC Physics, Condensed Matter SC Physics GA ZT216 UT WOS:000074061700066 ER PT J AU Gray, KE Steel, DG Hettinger, JD Eddy, MM AF Gray, KE Steel, DG Hettinger, JD Eddy, MM TI Modeling flux-flow dissipation from randomly placed strong-pinning sites and comparison with ion-irradiated cuprate superconductors SO PHYSICAL REVIEW B LA English DT Article ID VORTICES AB The interaction of an Abrikosov vortex lattice with randomly placed strong pinning centers (produced experimentally with heavy-ion irradiation) has been modeled with a particularly simple and powerful expression. Excellent quantitative fits to the dissipation in ion-irradiated Tl2Ba2CaCu2Ox are found for T/T-c = 0.75-0.9 over ranges of 10000 in resistance and 60 in field. The three free parameters are within a factor of 2 of expectations. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Superconductor Technol Inc, Santa Barbara, CA 93111 USA. RP Gray, KE (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 10 TC 3 Z9 3 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUN 1 PY 1998 VL 57 IS 21 BP 13894 EP 13898 DI 10.1103/PhysRevB.57.13894 PG 5 WC Physics, Condensed Matter SC Physics GA ZT216 UT WOS:000074061700075 ER PT J AU Voter, AF AF Voter, AF TI Parallel replica method for dynamics of infrequent events SO PHYSICAL REVIEW B LA English DT Article ID ISOMERIZATION DYNAMICS AB Although molecular-dynamics simulations can be parallelized effectively to treat large systems (10(6)-10(8) atoms), to date the power of parallel computers has not been harnessed to make analogous gains in time scale. I present a simple approach for infrequent-event systems that extends the time scale with high parallel efficiency. Integrating a replica of the system independently on each processor until the first transition occurs gives the correct transition-time distribution, and hence the correct dynamics. I obtain >90% efficiency simulating Cu(100) surface vacancy diffusion on 15 processors. C1 Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 14 TC 313 Z9 314 U1 1 U2 40 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 JUN 1 PY 1998 VL 57 IS 22 BP 13985 EP 13988 PG 4 WC Physics, Condensed Matter SC Physics GA ZU948 UT WOS:000074252500007 ER PT J AU Dzurak, AS Kane, BE Clark, RG Lumpkin, NE O'Brien, JL Facer, GR Starrett, RP Skougarevsky, A Nakagawa, H Miura, N Enomoto, Y Rickel, DG Goettee, JD Campbell, LJ Fowler, CM Mielke, C King, JC Zerwekh, WD Clark, D Bartram, BD Bykov, AI Tatsenko, OM Platonov, VV Mitchell, EE Herrmann, J Muller, KH AF Dzurak, AS Kane, BE Clark, RG Lumpkin, NE O'Brien, JL Facer, GR Starrett, RP Skougarevsky, A Nakagawa, H Miura, N Enomoto, Y Rickel, DG Goettee, JD Campbell, LJ Fowler, CM Mielke, C King, JC Zerwekh, WD Clark, D Bartram, BD Bykov, AI Tatsenko, OM Platonov, VV Mitchell, EE Herrmann, J Muller, KH TI Transport measurements of in-plane critical fields in YBa2Cu3O7-delta to 300T SO PHYSICAL REVIEW B LA English DT Article ID COMPLEX MICROWAVE CONDUCTIVITY; ZERO-TEMPERATURE LIMIT; MAGNETIC-FIELDS; INPLANE; STATE AB Thin-film YBa2Cu3O7-delta has been studied with in-plane magnetic fields B to 850 T, with good signal-to-noise to 300 T, using a GHz-transmission-line technique for electrical transport measurements in explosive-driven microsecond pulsed magnetic fields. At an ambient temperature of 1.6 K with B perpendicular to c axis we find an onset of dissipation at 150 T, the highest field reported, with a saturation of resistivity at 240 T. Comparison with the Pauli limit B-p = 155 T expected for this material suggests that the critical field is limited by spin paramagnetism. C1 Univ New S Wales, Sch Phys, Natl Pulsed Magnet Lab, Sydney, NSW 2052, Australia. Univ New S Wales, Sch Phys, Semicond Nanofabricat Facil, Sydney, NSW 2052, Australia. Univ Tokyo, Inst Solid State Phys, Tokyo 106, Japan. Int Technol Ctr, Superconduct Res Lab, Koto Ku, Tokyo 135, Japan. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. All Russain Res Inst Expt Phys, Arzamas 607200 16, Russia. CSIRO, Div Telecommun & Ind Phys, Epping, NSW 2121, Australia. RP Univ New S Wales, Sch Phys, Natl Pulsed Magnet Lab, Sydney, NSW 2052, Australia. RI Dzurak, Andrew/C-5973-2009; O'Brien, Jeremy/A-6290-2008 NR 24 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 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD JUN 1 PY 1998 VL 57 IS 22 BP 14084 EP 14087 PG 4 WC Physics, Condensed Matter SC Physics GA ZU948 UT WOS:000074252500032 ER PT J AU Evans, WJ Silvera, IF AF Evans, WJ Silvera, IF TI Index of refraction, polarizability, and equation of state of solid molecular hydrogen SO PHYSICAL REVIEW B LA English DT Article ID X-RAY-DIFFRACTION; MEGABAR PRESSURES; TEMPERATURE; ABSORPTION; DEUTERIUM; DIAMOND; GPA AB The index of refraction and the equation of state (EOS) of hydrogen have been measured to high pressures, leading to a determination of the pressure dependence of the polarizability to greater than 1 mbar. A simple method for measuring the index allows for straightforward extension of both the index and EOS measurements to the highest pressures achievable in a diamond-anvil cell. C1 Harvard Univ, Lyman Lab Phys, Cambridge, MA 02138 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Harvard Univ, Lyman Lab Phys, Cambridge, MA 02138 USA. NR 15 TC 27 Z9 27 U1 0 U2 4 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 JUN 1 PY 1998 VL 57 IS 22 BP 14105 EP 14109 DI 10.1103/PhysRevB.57.14105 PG 5 WC Physics, Condensed Matter SC Physics GA ZU948 UT WOS:000074252500035 ER PT J AU Beiden, SV Temmerman, WM Szotek, Z Gehring, GA Stocks, GM Wang, Y Nicholson, DMC Shelton, WA Ebert, H AF Beiden, SV Temmerman, WM Szotek, Z Gehring, GA Stocks, GM Wang, Y Nicholson, DMC Shelton, WA Ebert, H TI Real-space approach to the calculation of magnetocrystalline anisotropy in metals SO PHYSICAL REVIEW B LA English DT Article ID 1ST-PRINCIPLES DETERMINATION; MAGNETIC-PROPERTIES; SPIN; FE; DICHROISM; ENERGY; ALLOYS; IRON; NI; CO AB We have implemented the fully relativistic and spin-polarized extension of the locally self-consistent multiple-scattering method. We have calculated the spin and orbital magnetic moments and magnetocrystalline anisotropy energy of Fe, Ni, and Co in the face-centered-cubic (fcc) and hexagonal-close-packed(hcp) crystal structures. We have obtained fast convergence of these quantities in real space. Moreover, these results compare favorably with the results of conventional k-space methods. C1 Univ Sheffield, Dept Phys, Sheffield, S Yorkshire, England. SERC, Daresbury Lab, Warrington WA4 4AD, Cheshire, England. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Munchen, Inst Phys Chem, D-80333 Munchen, Germany. RP Univ Sheffield, Dept Phys, Sheffield, S Yorkshire, England. RI Stocks, George Malcollm/Q-1251-2016 OI Stocks, George Malcollm/0000-0002-9013-260X NR 39 TC 22 Z9 22 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 JUN 1 PY 1998 VL 57 IS 22 BP 14247 EP 14253 DI 10.1103/PhysRevB.57.14247 PG 7 WC Physics, Condensed Matter SC Physics GA ZU948 UT WOS:000074252500053 ER PT J AU Schellenberg, R Kisker, E Fanelsa, A Hillebrecht, FU Menchero, JG Kaduwela, AP Fadley, CS Van Hove, MA AF Schellenberg, R Kisker, E Fanelsa, A Hillebrecht, FU Menchero, JG Kaduwela, AP Fadley, CS Van Hove, MA TI Photoelectron diffraction: A source for magnetic dichroism in angle-resolved photoemission from ferromagnets SO PHYSICAL REVIEW B LA English DT Article ID CORE-LEVEL PHOTOEMISSION; LINEARLY POLARIZED-LIGHT; CIRCULAR-DICHROISM; FE; SCATTERING; EMISSION; SPECTRA AB Magnetic dichroism has been measured in angle-resolved core-level photoemission from the Fe 2p and 3p levels in epitaxially grown ultrathin films of Fe(001) and in an amorphous metallic glass with composition Fe78B13Si9. Unpolarized Al K alpha and Mg K alpha radiation was used for excitation, leading to diffraction patterns that are dominated by forward scattering along low-index crystallographic directions. The Fe(001) data for both total intensity and magnetic dichroism are quantitatively compared to theoretical calculations at both a two-atom single-scattering level and a multiatom multiple-scattering level. Strong effects on the magnetic dichroism due to photoelectron diffraction are found, and the combined angle and energy dependence of the dichroism shows a characteristic "checkered" pattern that should be generally observable in all single crystals. Comparing dichroism data obtained for single-crystal Fe films with those obtained from the amorphous glass and from two-atom and multiatom diffraction theory further permits estimating the relative contributions of free-atom-like dichroism and of photoelectron diffraction, with the free-atom dichroism (that is dominant along low-index directions) being smaller by about a factor of 2 to 4 than the maximum diffraction dichroism (that dominates away from low-index directions). Such photoelectron-diffraction-produced magnetic dichroism thus should provide a useful tool for studying magnetic order near single-crystal surfaces. The deviation of the zero in the dichroic asymmetry from the low-index directions is also found via photoelectron diffraction theory to be very sensitive to the s-to-d partial-wave phase difference, and the experimental data permit estimating this quantity and the solid-state effects on it. C1 Heinrich Heine Univ, Inst Angew Phys, D-40225 Dusseldorf, Germany. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Sci Mat, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Phys, Livermore, CA 95616 USA. RP Heinrich Heine Univ, Inst Angew Phys, D-40225 Dusseldorf, Germany. RI Van Hove, Michel/A-9862-2008; OI Van Hove, Michel/0000-0002-8898-6921; Kaduwela, Ajith/0000-0002-7236-2698 NR 29 TC 32 Z9 32 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 JUN 1 PY 1998 VL 57 IS 22 BP 14310 EP 14319 DI 10.1103/PhysRevB.57.14310 PG 10 WC Physics, Condensed Matter SC Physics GA ZU948 UT WOS:000074252500057 ER PT J AU Dodgson, MJW Geshkenbein, VB Nordborg, H Blatter, G AF Dodgson, MJW Geshkenbein, VB Nordborg, H Blatter, G TI Thermodynamics of the first-order vortex lattice melting transition in YBa2Cu3O7-delta SO PHYSICAL REVIEW B LA English DT Article ID TYPE-2 SUPERCONDUCTORS; ELASTIC ENERGY; INDUCTIONS; STATE AB Using the London approximation within the high-field scaling regime, we calculate the jump in the specific heat Delta c at the first-order melting transition of the vortex lattice in YBa2Cu3O7-delta. This has recently been measured [A. Schilling et al., Phys. Rev. Lett. 78, 4833 (1997)] and reported to be at least 100 times higher than expected from the fluctuations of field-induced vortices alone. We demonstrate how the correct treatment of the temperature dependence of the model parameters, which are singular at the mean-field B-c2 line, leads to good agreement between the predictions of the London model and the size of the experimental jump. In addition, we consider the changes in the slopes of the magnetization Delta(partial derivative M/partial derivative T) and Delta(partial derivative M/partial derivative H) at the transition. Using continuum anisotropic scaling theory we demonstrate the consistency of measurements at different angles of the magnetic field with respect to the crystal c axis. C1 ETH Honggerberg, CH-8093 Zurich, Switzerland. LD Landau Inst Theoret Phys, Moscow 117940, Russia. Argonne Natl Lab, Argonne, IL 60439 USA. RP ETH Honggerberg, CH-8093 Zurich, Switzerland. NR 21 TC 23 Z9 23 U1 1 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 JUN 1 PY 1998 VL 57 IS 22 BP 14498 EP 14506 DI 10.1103/PhysRevB.57.14498 PG 9 WC Physics, Condensed Matter SC Physics GA ZU948 UT WOS:000074252500078 ER PT J AU Aegerter, CM Johnson, ST Nuttall, WJ Lloyd, SH Wylie, MT Nutley, MP Forgan, EM Cubitt, R Lee, SL Paul, DM Yethiraj, M Mook, HA AF Aegerter, CM Johnson, ST Nuttall, WJ Lloyd, SH Wylie, MT Nutley, MP Forgan, EM Cubitt, R Lee, SL Paul, DM Yethiraj, M Mook, HA TI Observation of vortex lattice melting in twinned YBa2Cu3O7-x using neutron small-angle scattering SO PHYSICAL REVIEW B LA English DT Article ID SINGLE-CRYSTAL YBA2CU3O7; MAGNETIC-FLUX LATTICE; ELECTRONIC-STRUCTURE; ELASTIC THEORY; SUPERCONDUCTORS; TRANSITION; DISORDER; SYMMETRY; HEAT AB A neutron small-angle scattering study of the flux-line lattice in heavily twinned YBa2Cu3O7-x is presented. It is found that the diffraction signal disappears at temperatures well below: T-c, associated with a melting of the flux lattice. The shape of the melting line is consistent with both a Lindemann criterion and the scaling expected for a vortex-glass transition with the superconducting parameters from the three-dimensional XY model. The influence of twin planes on the structure of the vortex lattice and its melting is studied by applying; the field at different angles to the c axis. The results are compared with recent specific heat measurements on similar crystals. C1 Univ Zurich, Inst Phys, CH-8057 Zurich, Switzerland. Univ Birmingham, Sch Phys & Space Res, Birmingham B15 2TT, W Midlands, England. Inst Max Von Laue Paul Langevin, F-38042 Grenoble, France. Univ St Andrews, Dept Phys & Astron, St Andrews KY16 9SS, Fife, Scotland. Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands, England. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Univ Zurich, Inst Phys, CH-8057 Zurich, Switzerland. RI cubitt, robert/B-9408-2008; Lee, Stephen/G-9791-2016 OI Lee, Stephen/0000-0002-2020-3310 NR 32 TC 16 Z9 16 U1 0 U2 2 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 JUN 1 PY 1998 VL 57 IS 22 BP 14511 EP 14517 DI 10.1103/PhysRevB.57.14511 PG 7 WC Physics, Condensed Matter SC Physics GA ZU948 UT WOS:000074252500080 ER PT J AU Su, X Zuo, F Schlueter, JA Kelly, ME Williams, JM AF Su, X Zuo, F Schlueter, JA Kelly, ME Williams, JM TI Structural disorder and its effect on the superconducting transition temperature in the organic superconductor kappa-(BEDT-TTF)(2)Cu[N(CN)(2)]Br SO PHYSICAL REVIEW B LA English DT Article ID BEDT-TTF; TC; KAPPA-(BEDT-TTF)2CUBR; K-(BEDT-TTF)2CUBR AB In this paper, we report direct evidence of a structural transition in the organic superconductor kappa-(BEDT-TTF)(2)Cu[N(CN)(2)]Br near 80 K and the effect of disorder on the superconducting transition temperature. By cooling the sample from above 80 K, the interlayer magnetoresistance displays a bumplike feature, which increases sharply with increasing cooling rate. The rapidly cooled sample has a much larger resistivity and a lower transition temperature, which decreases linearly with increasing resistivity near the transition temperature. We propose that rapid cooling quenches the sample into a disordered state. Localized moments in the disordered state reduce the superconducting transition temperature. C1 Univ Miami, Dept Phys, Coral Gables, FL 33124 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Univ Miami, Dept Phys, Coral Gables, FL 33124 USA. NR 21 TC 57 Z9 57 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 JUN 1 PY 1998 VL 57 IS 22 BP R14056 EP R14059 DI 10.1103/PhysRevB.57.R14056 PG 4 WC Physics, Condensed Matter SC Physics GA ZU948 UT WOS:000074252500025 ER PT J AU Carr, SB Afnan, IR Gibson, BF AF Carr, SB Afnan, IR Gibson, BF TI Xi(-)d ->Lambda Lambda and the Lambda Lambda final state interaction SO PHYSICAL REVIEW C LA English DT Article ID BARYON-BARYON SCATTERING; UNITARY SYMMETRY AB The reaction Xi(-)d-->n Lambda Lambda is studied within the framework of the Faddeev equations as a possible tool to gain insight into the final state Lambda Lambda interaction. The neutron differential energy spectrum gives a final state interaction that is sensitive to both the Lambda Lambda amplitude at threshold and the coupling between the Lambda Lambda and Xi N channels. The latter is a result of interference between two mechanisms for the production of the final state, which suggests that this reaction could give a measure of flavor SU(3) violation in the two-baryon system. C1 Flinders Univ S Australia, Dept Phys, Adelaide, SA 5001, Australia. Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Carr, SB (reprint author), Flinders Univ S Australia, Dept Phys, GPO Box 2100, Adelaide, SA 5001, Australia. NR 14 TC 6 Z9 6 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 EI 1089-490X J9 PHYS REV C JI Phys. Rev. C PD JUN PY 1998 VL 57 IS 6 BP 2858 EP 2869 DI 10.1103/PhysRevC.57.2858 PG 12 WC Physics, Nuclear SC Physics GA ZU091 UT WOS:000074160700015 ER PT J AU Kharraja, B Ghugre, SS Garg, U Janssens, RVF Carpenter, MP Crowell, B Khoo, TL Lauritsen, T Nisius, D Reviol, W Mueller, WF Riedinger, LL Kaczarowski, R AF Kharraja, B Ghugre, SS Garg, U Janssens, RVF Carpenter, MP Crowell, B Khoo, TL Lauritsen, T Nisius, D Reviol, W Mueller, WF Riedinger, LL Kaczarowski, R TI Nuclear structure of Mo-94,Mo-95 at high spins SO PHYSICAL REVIEW C LA English DT Article ID SHELL-MODEL; BACKGROUND SUBTRACTION; COINCIDENCE DATA; STATES; TC-93; SPECTRA; RU-94; RH-95; MO-92 AB The high-spin level structures of Mo-94,Mo-95 (N= 52,53) have been investigated via the (CU)-C-65(S-36, alpha p2n)Mo and Cu-65(S-36, alpha pn)Mo-95 reactions at 142 MeV. The level schemes have been extended up to spin J approximate to 19h and excitation energies E-x approximate to 12 MeV. Spherical shell-model calculations have been performed and compared with the experimental energy levels. The level structure of Mo-94 exhibits a single-particle nature and the higher-angular-momentum states are dominated by the excitation of a g(9/2) neutron across the N=50 shell gap. The level sequences observed in Mo-95 have been interpreted on the basis of the spherical shell model and weak coupling of a d(5/2) Or a g(7/2) neutron to the Mo-94 core. C1 Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. Soltan Inst Nucl Studies, PL-05400 Swierk, Poland. RP Kharraja, B (reprint author), Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. RI Carpenter, Michael/E-4287-2015 OI Carpenter, Michael/0000-0002-3237-5734 NR 23 TC 20 Z9 21 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUN PY 1998 VL 57 IS 6 BP 2903 EP 2911 DI 10.1103/PhysRevC.57.2903 PG 9 WC Physics, Nuclear SC Physics GA ZU091 UT WOS:000074160700020 ER PT J AU Archer, DE Riley, MA Brown, TB Hartley, DJ Doring, J Johns, GD Pfohl, J Tabor, SL Simpson, J Sun, Y Egido, JL AF Archer, DE Riley, MA Brown, TB Hartley, DJ Doring, J Johns, GD Pfohl, J Tabor, SL Simpson, J Sun, Y Egido, JL TI Rotational bands in Yb-170 and Yb-171 and the projected shell model SO PHYSICAL REVIEW C LA English DT Article ID RARE-EARTH NUCLEI; HIGH-SPIN STATES; ANGULAR-MOMENTUM PROJECTION; ODD PROTON NUCLEI; CROSSING FREQUENCY; YRAST LINE; REGION AB Rotational bands in Yb-170 and Yb-171 have been studied with the reactions Er-170(alpha,xn)Yb174-x at 35 and 40 MeV. Considerable extensions have been made to the previously published level schemes, and new structures have been found in each nucleus. Angular correlation measurements and reduced transition probability [B(M1:I-->I-1)/B(E2:I-->I-2)] ratios have been extracted. Detailed comparisons are made with the first major projected shell model calculations for excited bands in an odd-N nucleus Yb-171. C1 Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. SERC, Daresbury Lab, CCLRC, Warrington WA4 4AD, Cheshire, England. Oak Ridge Natl Lab, Joint Inst Heavy Ion Res, Oak Ridge, TN 37831 USA. Drexel Univ, Dept Phys & Atmospher Sci, Philadelphia, PA 19104 USA. Univ Autonoma Madrid, Dept Fis Teor 111, E-28049 Madrid, Spain. RP Archer, DE (reprint author), Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. RI Sun, Yang/P-2417-2015; Egido, J. Luis/F-4921-2017 OI Egido, J. Luis/0000-0002-8292-6127 NR 42 TC 11 Z9 12 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUN PY 1998 VL 57 IS 6 BP 2924 EP 2943 DI 10.1103/PhysRevC.57.2924 PG 20 WC Physics, Nuclear SC Physics GA ZU091 UT WOS:000074160700022 ER PT J AU Myers, WD Swiatecki, WJ AF Myers, WD Swiatecki, WJ TI Nuclear equation of state SO PHYSICAL REVIEW C LA English DT Article ID DROPLET-MODEL; COMPRESSIBILITY AB We present a discussion of the equation of state of cold nuclear matter predicted by our recently completed Thomas-Fermi model. The equation is in the form of a three-term polynomial in the cube root of the density, with coefficients that are functions of the relative neutron excess delta. The coefficients are tabulated in the range from delta=0 (standard nuclear matter) to delta=1 (neutron matter), making it very easy to calculate, for a given delta, the pressure, compressibility, saturation binding, and any other property of the Thomas-Fermi equation of state. We discuss the empirical information concerning abnormal densities and large neutron excess that is contained in the measured values of the surface energy, surface diffuseness, and the neutron skin. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Myers, WD (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 13 TC 86 Z9 86 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUN PY 1998 VL 57 IS 6 BP 3020 EP 3025 DI 10.1103/PhysRevC.57.3020 PG 6 WC Physics, Nuclear SC Physics GA ZU091 UT WOS:000074160700028 ER PT J AU Vertse, T Kruppa, AT Liotta, RJ Nazarewicz, W Sandulescu, N Werner, TR AF Vertse, T Kruppa, AT Liotta, RJ Nazarewicz, W Sandulescu, N Werner, TR TI Shell corrections for finite depth potentials: Particle continuum effects SO PHYSICAL REVIEW C LA English DT Article ID LEVEL DENSITY; MEAN-FIELD; NUCLEI; FISSION AB Shell corrections of finite, spherical, one-body potentials are analyzed using a smoothing procedure which properly accounts for the contribution from the particle continuum, i.e., unbound states. Since the plateau condition for the smoothed single-particle energy seldom holds, a new recipe is suggested for the definition of the shell correction. The generalized Strutinsky smoothing procedure is compared with the results of the semiclassical Wigner-Kirkwood expansion. A good agreement has been found for weakly bound nuclei in the vicinity of the proton drip line. However, some deviations remain for extremely neutron-rich systems due to the pathological behavior of the semiclassical level density around the particle threshold. C1 Hungarian Acad Sci, Inst Nucl Res, H-4001 Debrecen, Hungary. Oak Ridge Natl Lab, Joint Inst Heavy Ion Res, Oak Ridge, TN 37831 USA. Royal Inst Technol, Phys Dept Frescati, S-10405 Stockholm, Sweden. Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Univ Warsaw, Inst Theoret Phys, PL-00681 Warsaw, Poland. Inst Atom Phys, R-76900 Bucharest, Romania. RP Vertse, T (reprint author), Hungarian Acad Sci, Inst Nucl Res, POB 51, H-4001 Debrecen, Hungary. NR 31 TC 32 Z9 32 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUN PY 1998 VL 57 IS 6 BP 3089 EP 3098 DI 10.1103/PhysRevC.57.3089 PG 10 WC Physics, Nuclear SC Physics GA ZU091 UT WOS:000074160700037 ER PT J AU Souliotis, GA Hanold, K Loveland, W Lhenry, I Morrissey, DJ Veeck, AC Wozniak, GJ AF Souliotis, GA Hanold, K Loveland, W Lhenry, I Morrissey, DJ Veeck, AC Wozniak, GJ TI Heavy residue formation in 20 MeV/nucleon Au-197-C-12 and Au-197-Al-27 collisions SO PHYSICAL REVIEW C LA English DT Article ID ION REACTIONS; TARGET FRAGMENTATION; MEV NUCLEON; EVAPORATION RESIDUES; INTERMEDIATE; ENERGY; EMISSION; DISTRIBUTIONS; MECHANISMS; FISSION AB The yields and velocity distributions of heavy residues and fission fragments from the reaction of 20 MeV/nucleon Au-197 with C-12 and Al-27 have been measured using the MSU A1200 fragment separator. The mass and isotopic distributions of the reaction products are generally consistent with previously measured radiochemical data. One observes, especially for the Au+Al reaction, the production of very neutron deficient nuclides, possibly including "new" nuclei. The heavy-residue velocity distributions can be resolved into components due to fusionlike collisions (incomplete fusion, nu(res)/nu(cn) similar or equal to 0.8) along with components due to more peripheral interactions. Fusionlike events were observed that lead to near-and trans-gold species. The observed mass and charge distributions of the fusionlike products, sorted by velocity, are compared with the results of simulations using PACE2 and GEMINI of the decay of the excited incomplete fusion products. The simulations, while reproducing the general features of the data, predict residue distributions that are too neutron deficient relative to the observed distributions. The observed yields of the trans-gold species are not predicted in the simulations. C1 Oregon State Univ, Dept Chem, Corvallis, OR 97331 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Michigan State Univ, Natl Superconducting Cyclotron Lab, E Lansing, MI 48824 USA. RP Souliotis, GA (reprint author), NCSR Demokritos, Inst Nucl Phys, GR-15310 Athens, Greece. NR 37 TC 11 Z9 11 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUN PY 1998 VL 57 IS 6 BP 3129 EP 3143 DI 10.1103/PhysRevC.57.3129 PG 15 WC Physics, Nuclear SC Physics GA ZU091 UT WOS:000074160700041 ER PT J AU Frlez, E Pocanic, D Assamagan, KA Chen, JP Keeter, KJ Marshall, RM Minehart, RC Smith, LC Dodge, GE Hanna, SS King, BH Knudson, JN AF Frlez, E Pocanic, D Assamagan, KA Chen, JP Keeter, KJ Marshall, RM Minehart, RC Smith, LC Dodge, GE Hanna, SS King, BH Knudson, JN TI Differential cross sections for pion charge exchange on the proton at 27.5 MeV SO PHYSICAL REVIEW C LA English DT Article ID SCATTERING; BREAKING AB We have measured pion single charge exchange differential cross sections on the proton at 27.5 MeV incident pi(-) kinetic energy in the center of momentum angular range between 0 degrees and 55 degrees. The extracted cross sections are compared with predictions of the standard pion-nucleon partial wave analysis and found to be in excellent agreement. C1 Univ Virginia, Dept Phys, Charlottesville, VA 22901 USA. Stanford Univ, Dept Phys, Stanford, CA 94305 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Frlez, E (reprint author), Univ Virginia, Dept Phys, Charlottesville, VA 22901 USA. RI Frlez, Emil/B-6487-2013 NR 31 TC 7 Z9 7 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUN PY 1998 VL 57 IS 6 BP 3144 EP 3152 DI 10.1103/PhysRevC.57.3144 PG 9 WC Physics, Nuclear SC Physics GA ZU091 UT WOS:000074160700042 ER PT J AU Long, SA Spicer, BM Raywood, KJ Abegg, R Alford, WP Celler, A Frekers, D Green, PE Hausser, O Helmer, RL Henderson, RS Hicks, KH Jackson, KP Jeppesen, RG King, NSP Miller, CA Moinester, MA Officer, VC Shute, GG Trudel, A Vetterli, MC Yavin, AI Yen, S AF Long, SA Spicer, BM Raywood, KJ Abegg, R Alford, WP Celler, A Frekers, D Green, PE Hausser, O Helmer, RL Henderson, RS Hicks, KH Jackson, KP Jeppesen, RG King, NSP Miller, CA Moinester, MA Officer, VC Shute, GG Trudel, A Vetterli, MC Yavin, AI Yen, S TI Spin-isovector giant resonances induced by (n,p) reactions on heavy nuclei SO PHYSICAL REVIEW C LA English DT Article ID GAMOW-TELLER STRENGTH; MICROSCOPIC ANALYSIS; SCATTERING; CONTINUUM; EXCITATIONS; SPECTRA; TRIUMF; ZR-90 AB Double differential cross sections from the Sn-120(n,p)In-120 and Ta-181(n,p)Hf-181 reactions at 298 MeV and the U-238(n,p)Pa-238 reaction at 318 MeV have been measured for excitation energies up to 50 MeV in the residual nucleus. These data, together with the previously published data from the Zr-90(n,p)Y-90 and Pb-208(n,p)Tl-208 reactions at 198 MeV, have been analyzed for spin-isovector resonances of multipolarities less than 7, using the multipole decomposition method. The strengths due to spin-isovector excitations of multipolarity less than 4 have been extracted. The anomalous behavior of the extracted spin-isovector quadrupole strength with target mass number is discussed with reference to the calculations of Leonardi et al. The cross section due to quasifree processes was calculated and subtracted from the data. The data after this subtraction were reanalyzed for spin-isovector resonances and the strengths due to multipolarities up to 3 were extracted. The strengths due to spin-isovector dipole and octupole excitations were compared to values calculated, for 1 (h) over bar omega transitions only, using the sum rules of Macfarlane. The behavior with target mass number is well represented by these sum rules. C1 Univ Melbourne, Sch Phys, Parkville, Vic 3052, Australia. TRIUMF, Vancouver, BC V6T 2A3, Canada. Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, Sch Phys, IL-69978 Tel Aviv, Israel. Simon Fraser Univ, Dept Phys, Burnaby, BC V5A 1S6, Canada. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Ohio Univ, Dept Phys, Athens, OH 45701 USA. Univ Western Ontario, Dept Phys, London, ON N6A 3K7, Canada. RP Long, SA (reprint author), Univ Melbourne, Sch Phys, Parkville, Vic 3052, Australia. NR 42 TC 9 Z9 9 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUN PY 1998 VL 57 IS 6 BP 3191 EP 3202 DI 10.1103/PhysRevC.57.3191 PG 12 WC Physics, Nuclear SC Physics GA ZU091 UT WOS:000074160700047 ER PT J AU Wilburn, WS Bowman, JD AF Wilburn, WS Bowman, JD TI Consistency of parity-violating pion-nucleon couplings extracted from measurements in F-18 and Cs-133 SO PHYSICAL REVIEW C LA English DT Article ID OPTICAL-ROTATION; ATOMIC LEAD; NONCONSERVATION AB The recent measurement of the nuclear anapole moment of Cs-133 has been interpreted to yield a value of the weak pion-nucleon coupling H-pi(1) which contradicts the upper limit from the F-18 experiments. We argue that because of the sensitivity of the anapole moment to H-rho(0) in the odd proton nucleus Cs-133, there is a combination of weak meson-nucleon couplings which satisfies both experiments and which is (barely) in agreement with theory. In addition, the anapole moment measurement in Tl-205 gives a constraint which is inconsistent with the value from Cs-133, calling into question the theory of nuclear anapole moments. We argue that measurements of directional asymmetry in (n) over right arrow + p --> d + gamma and in the photodisintegration of the deuteron by circularly polarized photons, combined with results from pp scattering, would determine H-pi(1) and several other weak meson-nucleon couplings in a model-independent way. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Wilburn, WS (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 31 TC 32 Z9 32 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUN PY 1998 VL 57 IS 6 BP 3425 EP 3429 DI 10.1103/PhysRevC.57.3425 PG 5 WC Physics, Nuclear SC Physics GA ZU091 UT WOS:000074160700070 ER PT J AU Wu, CY Simon, MW Cline, D Davis, GA Macchiavelli, AO Vetter, K AF Wu, CY Simon, MW Cline, D Davis, GA Macchiavelli, AO Vetter, K TI Production and spectroscopy of the neutron-rich nucleus Dy-166 SO PHYSICAL REVIEW C LA English DT Article ID REGION; ISOTOPES; FISSION; BANDS AB Yrast states up to spin 16 (H) over bar in Dy-166 were observed, for the first time, using a quasielastic neutron-transfer reaction in the bombardment of Sn-118 with Dy-164 at E-lab = 790 MeV. The ratio of the Dy-166 production cross section relative to the inelastic cross section, integrated over the c.m. scattering angle range 110 degrees to 140 degrees, is approximate to 0.0027. This experiment demonstrates that the improved sensitivity, provided by the new generation of highly segmented 4 pi gamma-ray arrays coupled to a 4 pi heavy-ion detector array, makes subbarrier heavy-ion-induced nucleon-transfer reactions a powerful probe of the structure of neutron-rich nuclei at moderately high spin. A comparison with the production of Dy-164 in the reaction between Sn-118 and Dy-162 is made. C1 Univ Rochester, Nucl Struct Res Lab, Rochester, NY 14627 USA. Lawrence Berkeley Natl Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Wu, CY (reprint author), Univ Rochester, Nucl Struct Res Lab, Rochester, NY 14627 USA. NR 15 TC 25 Z9 25 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUN PY 1998 VL 57 IS 6 BP 3466 EP 3469 DI 10.1103/PhysRevC.57.3466 PG 4 WC Physics, Nuclear SC Physics GA ZU091 UT WOS:000074160700077 ER PT J AU Bernstein, LA Becker, JA Younes, W Archer, DE Hauschild, K Johns, GD Nelson, RO Wilburn, WS Drake, DM AF Bernstein, LA Becker, JA Younes, W Archer, DE Hauschild, K Johns, GD Nelson, RO Wilburn, WS Drake, DM TI Probing reaction dynamics with the Pt-196(n,xn gamma) reactions for x <= 15 SO PHYSICAL REVIEW C LA English DT Article ID NEUTRON AB Discrete gamma-ray spectra have been measured as a function of incident neutron energy for nuclei produced in the Pt-196(n,xn gamma) reactions. Spectroscopy was done using the large-scale Compton suppressed Ge gamma-ray spectrometer GEANIE. The "white" source neutron beam was produced at the Los Alamos Neutron Science WNR facility. Reaction neutron energy was determined using the time-of-flight technique. Reaction-channel yields were inferred from the measured intensity sum of the 2(1)(+) --> 0(1)(+) and the 2(2)(+) --> 0(1)(+) transitions for the Pt-196(n,xn) reactions for x less than or equal to 15. Weisskopf-Ewing calculations (including precompound) done with the HMS-ALICE code correctly predict the bulk of the (n,xn) reaction products for low multiplicity. However, they do not accurately predict yield ratios of the different (n,xn) reactions for x greater than or equal to 9. In addition, there is no consistent experimental indication of charged-particle reaction channels (n,pxn) for incident neutron energies above 60 MeV where they are predicted to account for approximately 1/3 of the total reaction cross section. Several possible causes are discussed for these discrepancies. Finally, the region of E-J phase space populated in this reaction is probed for several of the strongest reaction channels through the observation of relative yields for different yrast and off-yrast states. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Amparo Corp, Santa Fe, NM USA. RP Bernstein, LA (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RI Hauschild, Karl/A-6726-2009 NR 10 TC 9 Z9 9 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUN PY 1998 VL 57 IS 6 BP R2799 EP R2803 DI 10.1103/PhysRevC.57.R2799 PG 5 WC Physics, Nuclear SC Physics GA ZU091 UT WOS:000074160700005 ER PT J AU Gollwitzer, A Hertenberger, R Metz, A Schiemenz, P Valnion, BD Graw, G Blasi, N Lucchini, S Micheletti, S Pignanelli, M de Leo, R Gill, RL Hategan, C Casten, RF AF Gollwitzer, A Hertenberger, R Metz, A Schiemenz, P Valnion, BD Graw, G Blasi, N Lucchini, S Micheletti, S Pignanelli, M de Leo, R Gill, RL Hategan, C Casten, RF TI Experimental study of the deformed nucleus Sm-153 via ((d)over-right-arrow,t) and average resonance capture as a test case for the multiorbit interacting boson fermion model SO PHYSICAL REVIEW C LA English DT Article AB The Sm-154(-->(d),t) reaction at high energy resolution (n,y), average resonance capture (ARC), and coincidence measurements were performed to study the deformed nucleus Sm-153. Strength distributions from (-->(d),t) and completeness for I-pi = 1/2(-) and 3/2(-) states up to 1500 keV from ARC provide one of the first detailed tests of the interacting boson fermion model (IBFM) in a deformed nucleus in a multiorbit environment. For negative parity states the model accounts for the large number of low spin (1/2(-), 3/2(-)) states much better than the Nilsson model since the even-even core in the IBFM calculations automatically includes excited vibrational states. The IBFM calculations also predict (d,t) spectroscopic factors better than the Nilsson model with pairing and Coriolis mixing. Neither the IBFM nor the Nilsson approach can explain the low lying positive parity states. The IBFM calculations show that for certain combinations of parameters, the monopole term in the boson-fermion Hamiltonian has more than a scaling effect: it can attenuate the Coriolis mixing (energy staggering). Finally suggested improvements in the treatment of pairing in the IBFM are made. C1 Univ Munchen, Sekt Phys, D-85748 Garching, Germany. Univ Milan, Dipartimento Fis, I-20133 Milan, Italy. Univ Bari, Bari, Italy. Sez INFN Bari, Bari, Italy. Brookhaven Natl Lab, Upton, NY 11973 USA. Inst Atom Phys, R-76900 Bucharest, Romania. Yale Univ, AW Wright Nucl Struct Lab, New Haven, CT 06520 USA. RP Gollwitzer, A (reprint author), Univ Munchen, Sekt Phys, D-85748 Garching, Germany. NR 20 TC 4 Z9 4 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUN PY 1998 VL 57 IS 6 BP R2781 EP R2785 DI 10.1103/PhysRevC.57.R2781 PG 5 WC Physics, Nuclear SC Physics GA ZU091 UT WOS:000074160700001 ER PT J AU Maris, P Roberts, CD Schmidt, S AF Maris, P Roberts, CD Schmidt, S TI Chemical potential dependence of pi and rho properties SO PHYSICAL REVIEW C LA English DT Article ID NON-PERTURBATIVE CALCULATION; GAUGE GLUON PROPAGATOR; INFRARED LIMIT; CONFINEMENT AB Using a confining, Dyson-Schwinger equation model of QCD at finite temperature (T) and chemical potential (mu), we study the behavior of [(q) over bar q], m(pi), f(pi) and the masses of the rho- and phi-mesons. For each of these quantities there is a necessary anticorrelation between its response to T and its response to mu. ( -[(q) over bar q]) and f(pi) decrease with T and increase with mu; m(pi) is almost insensitive to T and mu until very near the border of the confinement domain: the mass of the longitudinal component of the vector mesons increases with T and decreases with mu. At T=0, the rho-meson mass is reduced by approximately 15% at nuclear matter density. These results are a consequence of the necessary momentum-dependence of the dressed-quark self-energy. C1 Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Univ Rostock, Fachbereich Phys, D-18051 Rostock, Germany. RP Maris, P (reprint author), Argonne Natl Lab, Div Phys, Bldg 203, Argonne, IL 60439 USA. NR 24 TC 22 Z9 23 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUN PY 1998 VL 57 IS 6 BP R2821 EP R2825 DI 10.1103/PhysRevC.57.R2821 PG 5 WC Physics, Nuclear SC Physics GA ZU091 UT WOS:000074160700010 ER PT J AU Wuosmaa, AH Conner, CM Ahmad, I Back, BB Betts, RR Dunford, RW Fischer, SM Ganz, R Greene, JP Kaloskamis, NI Lamm, L Lister, CJ Nanal, V Roa, DE Schiffer, JP AF Wuosmaa, AH Conner, CM Ahmad, I Back, BB Betts, RR Dunford, RW Fischer, SM Ganz, R Greene, JP Kaloskamis, NI Lamm, L Lister, CJ Nanal, V Roa, DE Schiffer, JP TI Positron-electron angular correlations in internal pair conversion SO PHYSICAL REVIEW C LA English DT Article AB The internal pair conversion (IPC) of transitions in Pb nuclei has been studied. Recent calculations of IPC for transitions with energies up to 2 MeV predict large differences in the shapes of the angular correlations according to their magnetic or electric character. We have measured absolute pair-conversion coefficients for E1 transitions in Pb-206 and an M1 transition in Pb-207 with uncertainties three to five times smaller than previous measurements. The measured positron-electron angular correlations are in good agreement with the predictions of the recent calculations and display the predicted differences between the electric and magnetic cases. C1 Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Univ Illinois, Dept Phys, Chicago, IL 60607 USA. Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. RP Wuosmaa, AH (reprint author), Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. NR 22 TC 2 Z9 2 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUN PY 1998 VL 57 IS 6 BP R2794 EP R2798 DI 10.1103/PhysRevC.57.R2794 PG 5 WC Physics, Nuclear SC Physics GA ZU091 UT WOS:000074160700004 ER PT J AU Bonvicini, G Cinabro, D Greene, R Perera, LP Zhou, GJ Chadha, M Chan, S Eigen, G Miller, JS O'Grady, C Schmidtler, M Urheim, J Weinstein, AJ Wurthwein, F Bliss, DW Masek, G Paar, HP Prell, S Sharma, V Asner, DM Gronberg, J Hill, TS Lange, DJ Morrison, RJ Nelson, HN Nelson, TK Roberts, D Ryd, A Balest, R Behrens, BH Ford, WT Park, H Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Bloom, K Boisvert, V Cassel, DG Crowcroft, DS Dickson, M von Dombrowski, S Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kandaswamy, J Kim, PC Kreinick, DL Lee, T Liu, Y Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Valant-Spaight, B Ward, C Athanas, M Avery, P Jones, CD Lohner, M Patton, S Prescott, C Yelton, J Zheng, J Brandenburg, G Briere, RA Ershov, A Gao, YS Kim, DYJ Wilson, R Yamamoto, H Browder, TE Li, Y Rodriguez, JL Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Selen, M Thaler, JJ Edwards, KW Bellerive, A Janicek, R MacFarlane, DB Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Darling, C Davis, R Kotov, S Kravchenko, I Kwak, N Zhou, L Anderson, S Kubota, Y Lee, SJ O'Neill, JJ Poling, R Riehle, T Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Timm, S Wappler, F Anastassov, A Duboscq, JE Fujino, D Gan, KK Hart, T Honscheid, K Kagan, H Kass, R Lee, J Spencer, MB Sung, M Undrus, A Wanke, R Wolf, A Zoeller, MM Nemati, B Richichi, SJ Ross, WR Severini, H Skubic, P Bishai, M Fast, J Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ Yurko, M Glenn, S Johnson, SD Kwon, Y Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Savinov, V Ugolini, D Wang, R Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Shelkov, V Staeck, J Stroynowski, R Volobouev, I Ye, J Artuso, M Azfar, F Efimov, A Goldberg, M He, D Kopp, S Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Viehhauser, G Xing, X Bartlet, J Csorna, SE Jain, V McLean, KW Marka, S Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S AF Bonvicini, G Cinabro, D Greene, R Perera, LP Zhou, GJ Chadha, M Chan, S Eigen, G Miller, JS O'Grady, C Schmidtler, M Urheim, J Weinstein, AJ Wurthwein, F Bliss, DW Masek, G Paar, HP Prell, S Sharma, V Asner, DM Gronberg, J Hill, TS Lange, DJ Morrison, RJ Nelson, HN Nelson, TK Roberts, D Ryd, A Balest, R Behrens, BH Ford, WT Park, H Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Bloom, K Boisvert, V Cassel, DG Crowcroft, DS Dickson, M von Dombrowski, S Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kandaswamy, J Kim, PC Kreinick, DL Lee, T Liu, Y Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Valant-Spaight, B Ward, C Athanas, M Avery, P Jones, CD Lohner, M Patton, S Prescott, C Yelton, J Zheng, J Brandenburg, G Briere, RA Ershov, A Gao, YS Kim, DYJ Wilson, R Yamamoto, H Browder, TE Li, Y Rodriguez, JL Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Selen, M Thaler, JJ Edwards, KW Bellerive, A Janicek, R MacFarlane, DB Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Darling, C Davis, R Kotov, S Kravchenko, I Kwak, N Zhou, L Anderson, S Kubota, Y Lee, SJ O'Neill, JJ Poling, R Riehle, T Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Timm, S Wappler, F Anastassov, A Duboscq, JE Fujino, D Gan, KK Hart, T Honscheid, K Kagan, H Kass, R Lee, J Spencer, MB Sung, M Undrus, A Wanke, R Wolf, A Zoeller, MM Nemati, B Richichi, SJ Ross, WR Severini, H Skubic, P Bishai, M Fast, J Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ Yurko, M Glenn, S Johnson, SD Kwon, Y Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Savinov, V Ugolini, D Wang, R Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Shelkov, V Staeck, J Stroynowski, R Volobouev, I Ye, J Artuso, M Azfar, F Efimov, A Goldberg, M He, D Kopp, S Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Viehhauser, G Xing, X Bartlet, J Csorna, SE Jain, V McLean, KW Marka, S Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S TI Study of semileptonic decays of B mesons to charmed baryons SO PHYSICAL REVIEW D LA English DT Article AB Using data collected by the CLEO II detector at a center-of-mass energy on or near the Y(4S) resonance; we have determined the 90% confidence level upper limit B((B) over bar --> #Lambda(c)(+) e(-)X)/B((B) over bar-->(Lambda(c)(+) or <(Lambda)over bar>(-)(c))X)<0.05 for electrons with momentum above 0.6 GeV/c. We have also obtained the limit B(B- --> Lambda(c)(+) (p) over bar e(-) (v) over bar(e))/B((B) over bar --> Lambda(c)(+) (p) over bar X) <0.04 at the 90% confidence level and measured the ratio B((B) over bar-->Lambda(c)(+)(p) over bar X)/B((B) over bar-->(Lambda(c)(+) or <(Lambda)over bar>(-)(c))X) = 0.57 +/- 0.05 +/- 0.05. C1 Wayne State Univ, Detroit, MI 48202 USA. CALTECH, Pasadena, CA 91125 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. Univ Colorado, Boulder, CO 80309 USA. Cornell Univ, Ithaca, NY 14853 USA. Univ Florida, Gainesville, FL 32611 USA. Harvard Univ, Cambridge, MA 02138 USA. Univ Hawaii Manoa, Honolulu, HI 96822 USA. Univ Illinois, Urbana, IL 61801 USA. Carleton Univ, Ottawa, ON K1S 5B6, Canada. McGill Univ, Montreal, PQ H3A 2T8, Canada. Ithaca Coll, Ithaca, NY 14850 USA. Univ Kansas, Lawrence, KS 66045 USA. Univ Minnesota, Minneapolis, MN 55455 USA. SUNY Albany, Albany, NY 12222 USA. Ohio State Univ, Columbus, OH 43210 USA. Univ Oklahoma, Norman, OK 73019 USA. Purdue Univ, W Lafayette, IN 47907 USA. Univ Rochester, Rochester, NY 14627 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. So Methodist Univ, Dallas, TX 75275 USA. Syracuse Univ, Syracuse, NY 13244 USA. Vanderbilt Univ, Nashville, TN 37235 USA. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. Univ Texas, Austin, TX 78712 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. BINP, RU-630090 Novosibirsk, Russia. Yonsei Univ, Seoul 120749, South Korea. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Bonvicini, G (reprint author), Wayne State Univ, Detroit, MI 48202 USA. RI Briere, Roy/N-7819-2014; OI Poling, Ronald/0000-0001-7305-4702; Bloom, Kenneth/0000-0002-4272-8900; Briere, Roy/0000-0001-5229-1039; Bean, Alice/0000-0001-5967-8674 NR 9 TC 6 Z9 6 U1 1 U2 2 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 JUN 1 PY 1998 VL 57 IS 11 BP 6604 EP 6608 DI 10.1103/PhysRevD.57.6604 PG 5 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ZR642 UT WOS:000073999200006 ER PT J AU Arkani-Hamed, N Murayama, H AF Arkani-Hamed, N Murayama, H TI Renormalization group invariance of exact results in supersymmetric gauge theories SO PHYSICAL REVIEW D LA English DT Article ID MODULI SPACES; BREAKING; DUALITY; VACUA AB We clarify the notion of Wilsonian renormalization group (RG) invariance in supersymmetric gauge theories, which states that low-energy physics can be kept fixed when one changes the ultraviolet cutoff, provided appropriate changes are made to the bare coupling constants in the Lagrangian. We first pose a puzzle on how a quantum modified constraint [such as pf(Q(i)Q(j))=Lambda(2(N + 1)) in SP(N) theories with N + 1 flavors] can be RC invariant, since the bare fields Q(i) receive wave function renormalization when one changes the ultraviolet cutoff, while we naively regard the scale Lambda as RG invariant. The resolution is that Lambda is not RG invariant if one sticks to canonical normalization for the bare fields as is conventionally done in held theory. We derive a formula for how Lambda must be changed when one changes the ultraviolet cutoff. We then compare our formula to known exact results and show that their consistency requires the change in Lambda we have found. Finally, we apply our result to models of supersymmetry breaking due to quantum modified constraints. The RG invariance helps us to determine the effective potential along the classical flat directions found in these theories. In particular, the inverted hierarchy mechanism does not occur in the original version of these models. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RI Murayama, Hitoshi/A-4286-2011 NR 20 TC 60 Z9 60 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 JUN 1 PY 1998 VL 57 IS 11 BP 6638 EP 6648 DI 10.1103/PhysRevD.57.6638 PG 11 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ZR642 UT WOS:000073999200010 ER PT J AU Blanford, G Gollwitzer, K Mandelkern, M Schultz, J Takei, G Zioulas, G Christian, DC Munger, CT AF Blanford, G Gollwitzer, K Mandelkern, M Schultz, J Takei, G Zioulas, G Christian, DC Munger, CT TI Measuring the antihydrogen Lamb shift with a relativistic antihydrogen beam SO PHYSICAL REVIEW D LA English DT Article ID POSITRON CAPTURE; PAIR PRODUCTION; HYDROGEN-ATOM; H IONS; FIELD AB We propose an experiment to measure the Lamb shift and fine structure (the intervals 2s(1/2)-2p(1/2), and 2p(1/2)-2p(3/2)) in antihydrogen. A sample of 10 000 antihydrogen atoms at a momentum of 8.85 GeV/c suffices to measure the Lamb shift to 5% and the fine structure to 1%. Atomic collisions excite antihydrogen atoms to states with n =2; field ionization in a Lorentz-transformed laboratory magnetic field then prepares a particular n = 2 state, and is used again to analyze that state after it is allowed to oscillate in a region of zero field. This experiment is feasible at Fermilab. C1 Univ Calif Irvine, Irvine, CA 92717 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Blanford, G (reprint author), Univ Calif Irvine, Irvine, CA 92717 USA. NR 23 TC 15 Z9 15 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUN 1 PY 1998 VL 57 IS 11 BP 6649 EP 6655 DI 10.1103/PhysRevD.57.6649 PG 7 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ZR642 UT WOS:000073999200011 ER PT J AU Kamal, B AF Kamal, B TI Drell-Yan forward-backward and spin asymmetries for arbitrary vector boson production at next-to-leading order SO PHYSICAL REVIEW D LA English DT Article ID SUPERSYMMETRIC DIMENSIONAL REGULARIZATION; PARTON DISTRIBUTIONS; RADIATIVE-CORRECTIONS; SPLITTING FUNCTIONS; PERTURBATION-THEORY; QCD; SCATTERING; MODEL; NUCLEON; SCHEME AB Longitudinally polarized, unpolarized and forward-backward mass differential cross sections for Drell-Yan lepton-pair production by arbitrary vector bosons are calculated in next-to-leading order (NLO) QCD. Analytical results are presented in a form valid for all consistent n-dimensional regularization schemes, with the mass factorization scheme kept general. NLO predictions for all Drell-Yan type processes (W+/-, Z and y*) at BNL's Relativistic Heavy Ion Collider (RHIC) are made using polarized parton distributions which fit the recent deep-inelastic scattering data. These are examined as tools in the determination of the polarized parton distributions and the unpolarized (u) over bar/(d) over bar ratio. NLO predictions for the forward-backward lepton asymmetry at Fermilab are made and the precision determination of sin(2) theta(W) from future runs is studied. In all the above, the QCD corrections are found to be significant. An introductory discussion is given of various theoretical issues, such as allowable factorization and regularization schemes, and scale dependences. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Kamal, B (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 63 TC 28 Z9 28 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUN 1 PY 1998 VL 57 IS 11 BP 6663 EP 6691 DI 10.1103/PhysRevD.57.6663 PG 29 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ZR642 UT WOS:000073999200013 ER PT J AU Afanasev, A Page, PR AF Afanasev, A Page, PR TI Photoproduction and electroproduction of J(PC) = 1(-+) exotics SO PHYSICAL REVIEW D LA English DT Article ID FLUX-TUBE BREAKING; HYBRID MESONS; DECAY AB We estimate the kinematic dependence of the exclusive photo- and electro-production of J(PC)=1(-+) exotic mesons due to pi exchange. We show that the kinematic dependence is largely independent of the exotic meson form factor, which is explicitly derived for a 1(-+) isovector hybrid meson in the flux-tube model of Isgur and Paton. The relevance to experiments currently planned at Jefferson Lab is indicated. C1 Thomas Jefferson Natl Accelerator Facil, Theory Grp, Newport News, VA 23606 USA. RP Afanasev, A (reprint author), N Carolina Cent Univ, Durham, NC 27707 USA. RI Page, Philip/L-1885-2015; OI Page, Philip/0000-0002-2201-6703; Afanasev, Andrei/0000-0003-0679-3307 NR 21 TC 22 Z9 22 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUN 1 PY 1998 VL 57 IS 11 BP 6771 EP 6777 DI 10.1103/PhysRevD.57.6771 PG 7 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ZR642 UT WOS:000073999200021 ER PT J AU Luty, MA Terning, J AF Luty, MA Terning, J TI New mechanisms of dynamical supersymmetry breaking and direct gauge mediation SO PHYSICAL REVIEW D LA English DT Article ID ELECTRIC-MAGNETIC DUALITY; MODULI SPACES; FERMIONS; MODEL; VACUA AB We construct supersymmetric gauge theories with new mechanisms of dynamical supersymmetry breaking. The models have flat directions at the classical level, and different mechanisms lift these flat directions in different regions of the classical moduli space, in one branch of the moduli space, supersymmetry is broken by confinement in a novel manner. The models contain only dimensionless couplings and have large groups of unbroken global symmetries, making them potentially interesting for model building. As an illustrative application, we couple the standard model gauge group to a model with an SU(5) global symmetry, resulting in a model with composite messengers and a nonminimal spectrum of superpartner masses. C1 Univ Maryland, Dept Phys, College Pk, MD 20742 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theory Grp, Berkeley, CA 94720 USA. RP Luty, MA (reprint author), Univ Maryland, Dept Phys, College Pk, MD 20742 USA. OI Terning, John/0000-0003-1367-0575 NR 46 TC 20 Z9 20 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUN 1 PY 1998 VL 57 IS 11 BP 6799 EP 6806 DI 10.1103/PhysRevD.57.6799 PG 8 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ZR642 UT WOS:000073999200025 ER PT J AU Bora, K Jaffe, RL AF Bora, K Jaffe, RL TI Double-scattering contribution to b(1)(x,Q(2)) in the deuteron SO PHYSICAL REVIEW D LA English DT Article AB We study the tensor structure function b(1)(x,Q(2)) in deep inelastic scattering of an electron from a polarized deuteron target. We model the electron-nucleon cross section at the starting point for Q(2) evolution by vector-meson dominance. Shadowing due to the double scattering of vector mesons, along with the presence of a d-state admixture in a ground-state deuteron wave function gives rise to a nonvanishing contribution to b(1)(x,Q(2)). We find a large enhancement at low x in qualitative agreement with other recent estimates of double-scattering contributions to b(1)(x,Q(2)). If the model is valid, it should apply within the range of present fixed-target experiments. C1 MIT, Ctr Theoret Phys, Nucl Sci Lab, Cambridge, MA 02139 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. Brookhaven Natl Lab, RIKEN, BNL Res Ctr, Upton, NY 11973 USA. RP Bora, K (reprint author), MIT, Ctr Theoret Phys, Nucl Sci Lab, Cambridge, MA 02139 USA. NR 17 TC 21 Z9 21 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUN 1 PY 1998 VL 57 IS 11 BP 6906 EP 6911 DI 10.1103/PhysRevD.57.6906 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ZR642 UT WOS:000073999200036 ER PT J AU Balazs, C Berger, EL Mrenna, S Yuan, CP AF Balazs, C Berger, EL Mrenna, S Yuan, CP TI Photon pair production with soft gluon resummation in hadronic interactions SO PHYSICAL REVIEW D LA English DT Article ID TRANSVERSE-MOMENTUM DISTRIBUTION; TO-LEADING-ORDER; QUARK PRODUCTION; BOSON PRODUCTION; CROSS-SECTIONS; HIGGS-BOSON; BACK JETS; QCD; COLLISIONS; ANNIHILATION AB The production rate and kinematic distributions of isolated photon pairs produced in hadron interactions are studied. The effects of the initial-state multiple soft-gluon emission to the scattering subprocesses q (q) over bar,qg, and gg-->gamma gamma X are resummed with the Collins-Soper-Sterman soft gluon resummation formalism. The effects of fragmentation photons from qg-->gamma q, followed by q-->gamma X, are also studied. The results are compared with data from the Fermilab Tevatron collider. A prediction of the production rate and kinematic distributions of the diphoton pair in proton-nucleon reactions is also presented. C1 Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. Argonne Natl Lab, Div High Energy Phys, Argonne, IL 60439 USA. RP Balazs, C (reprint author), Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. NR 50 TC 58 Z9 58 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUN 1 PY 1998 VL 57 IS 11 BP 6934 EP 6947 DI 10.1103/PhysRevD.57.6934 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ZR642 UT WOS:000073999200039 ER PT J AU Geer, S AF Geer, S TI Neutrino beams from muon storage rings: Characteristics and physics potential SO PHYSICAL REVIEW D LA English DT Article ID OSCILLATIONS; SEARCH AB High-intensity high-energy neutrino beams could be produced by exploiting a very intense future muon source, and allowing the muons to decay in a storage ring containing a long straight section. Taking the parameters of muon source designs that are currently under study, the characteristics of the neutrino beams that could be produced are discussed and some examples of their physics potential given. It is shown that the neutrino and antineutrino beam intensities may be sufficient to produce hundreds of charged current interactions per year in a detector on the far side of the Earth. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Geer, S (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 24 TC 435 Z9 435 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUN 1 PY 1998 VL 57 IS 11 BP 6989 EP 6997 DI 10.1103/PhysRevD.57.6989 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ZR642 UT WOS:000073999200043 ER PT J AU Zhang, LZ Goity, JL AF Zhang, LZ Goity, JL TI Decays K-L -> l(+)l(-)l '(+)l '(-) reexamined SO PHYSICAL REVIEW D LA English DT Article ID FORM-FACTOR; BRANCHING RATIO; KL->E+E-GAMMA AB The double lepton pair decay modes of the K-L meson are analyzed including all contributions of order p(6) in chiral perturbation theory. The experimentally established e(+)e(-)e(+)e(-) mode and the recently observed e(+)e(-)mu(+)mu(-) mode are discussed in detail. C1 Hampton Univ, Dept Phys, Hampton, VA 23668 USA. Jefferson Lab, Newport News, VA 23606 USA. RP Zhang, LZ (reprint author), Hampton Univ, Dept Phys, Hampton, VA 23668 USA. NR 9 TC 8 Z9 8 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUN 1 PY 1998 VL 57 IS 11 BP 7031 EP 7033 DI 10.1103/PhysRevD.57.7031 PG 3 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ZR642 UT WOS:000073999200049 ER PT J AU Feit, MD Komashko, AM Musher, SL Rubenchik, AM Turitsyn, SK AF Feit, MD Komashko, AM Musher, SL Rubenchik, AM Turitsyn, SK TI Electron cavitation and relativistic self-focusing in underdense plasma SO PHYSICAL REVIEW E LA English DT Article ID LASER-PULSE; PROPAGATION AB An improved cavitation model shows that stable beam channeling and electron cavitation occur for relativistic laser intensities even at powers hundreds of times larger than the critical power for self-focusing. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Davis, Dept Appl Sci, Livermore, CA 94550 USA. Russian Acad Sci, Inst Automat & Electrometry, Novosibirsk 630090, Russia. RP Feit, MD (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-439, Livermore, CA 94550 USA. RI Feit, Michael/A-4480-2009 NR 15 TC 41 Z9 43 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD JUN PY 1998 VL 57 IS 6 BP 7122 EP 7125 DI 10.1103/PhysRevE.57.7122 PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA ZU947 UT WOS:000074252400113 ER PT J AU Zimmermann, F AF Zimmermann, F TI Impedance and wake field in a superconducting beam pipe SO PHYSICAL REVIEW E LA English DT Article AB The impedance and the longitudinal wake field in a superconducting beam pipe are derived. At low frequencies, this impedance is purely inductive, while at higher frequencies it approaches the resistive-wall impedance of a normal conductor. For very short bunches, the resistive heating of the beam pipe can induce quenches of the superconductor. C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Zimmermann, F (reprint author), Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 14 TC 1 Z9 1 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD JUN PY 1998 VL 57 IS 6 BP 7146 EP 7152 DI 10.1103/PhysRevE.57.7146 PG 7 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA ZU947 UT WOS:000074252400116 ER PT J AU Rourke, DE Bush, SD AF Rourke, DE Bush, SD TI Inversion of the bloch equations with T-2 relaxation: An application of the dressing method SO PHYSICAL REVIEW E LA English DT Article ID NUCLEAR-MAGNETIC-RESONANCE; SUPERPOSITION FORMULAS; SCATTERING TRANSFORM; NMR-SPECTROSCOPY; PROTON NMR; FOURIER; EVOLUTION AB The Bloch equations, with time-varying driving field, and T-2 relaxation, are expressed as a scattering problem, with Gamma(2 )= 1/T-2 as the scattering parameter, or eigenvalue. When the rf pulse, describing the driving field, is real, this system is equivalent to the 2x2 Zakharov-Shabat eigenvalue problem. In general, for complex rf pulses, the system is a third-order scattering problem. These systems can be inverted, to provide the rf pulse needed to obtain a given magnetization response as a function of Gamma(2) In particular, the class of "soliton pulses" are described, which have utility as T-2-selective pulses. For the third-order case, the dressing method is used to calculate these pulses. Constraints on the dressing data used in this method are derived, as a consequence of the structure of the Bloch equations. Nonlinear superposition formulas are obtained, which enable soliton pulses to be calculated efficiently. Examples of one-soliton and three-soliton pulses are given. A closed-form expression for the effect of T-1 relaxation for the one-soliton pulse is obtained. The pulses are tested numerically and experimentally, and found to work as predicted. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Rourke, DE (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. EM rourke@magres.nottingham.ac.uk NR 36 TC 7 Z9 7 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD JUN PY 1998 VL 57 IS 6 BP 7216 EP 7230 DI 10.1103/PhysRevE.57.7216 PG 15 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA ZU947 UT WOS:000074252400124 ER PT J AU Luscombe, JH Luban, M AF Luscombe, JH Luban, M TI Simplified recursive algorithm for Wigner 3j and 6j symbols SO PHYSICAL REVIEW E LA English DT Article ID ANGULAR MOMENTA; 3J-COEFFICIENTS; 6J-COEFFICIENTS AB We present a highly accurate, ab initio recursive algorithm for evaluating the Wigner 3j and 6j symbols. Our method makes use of two-term, nonlinear recurrence relations that an obtained from the standard three-term recurrence relations satisfied by these quantities. The use of two-term recurrence relations eliminates the need for rescaling of iterates to control numerical overflows and thereby simplifies the widely used recursive algorithm of Schulten and Gordon. C1 USN, Postgrad Sch, Dept Phys, Monterey, CA 93943 USA. Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames, IA 50011 USA. RP Luscombe, JH (reprint author), USN, Postgrad Sch, Dept Phys, Monterey, CA 93943 USA. NR 9 TC 16 Z9 16 U1 1 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD JUN PY 1998 VL 57 IS 6 BP 7274 EP 7277 DI 10.1103/PhysRevE.57.7274 PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA ZU947 UT WOS:000074252400131 ER PT J AU Beardmore, KM Gronbech-Jensen, N AF Beardmore, KM Gronbech-Jensen, N TI Efficient molecular dynamics scheme for the calculation of dopant profiles due to ion implantation SO PHYSICAL REVIEW E LA English DT Article ID BORON IMPLANTATION; ENERGY-RANGE; SILICON; SIMULATION; CRYSTALLINE; ALUMINUM AB We present a highly efficient molecular dynamics scheme for calculating the concentration depth profile of dopants in ion irradiated materials. The scheme incorporates several methods for reducing the computational overhead, plus a rare event algorithm that allows statistically reliable results to be obtained over a range of several orders of magnitude in the dopant concentration. We give examples of using this scheme for calculating concentration profiles of dopants in crystalline silicon. Here we can predict the experimental profile over five orders of magnitude for both channeling and nonchanneling implants at energies up to hundreds of keV. The scheme has advantages over binary collision approximation (BCA) simulations, in that it does not rely on a large set of empirically fitted parameters. Although our scheme has a greater computational overhead than the BCA, it is far superior in the low ion energy regime, where the BCA scheme becomes invalid. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Beardmore, KM (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 31 TC 58 Z9 59 U1 0 U2 8 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD JUN PY 1998 VL 57 IS 6 BP 7278 EP 7287 DI 10.1103/PhysRevE.57.7278 PG 10 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA ZU947 UT WOS:000074252400132 ER PT J AU Kachru, S Silverstein, E AF Kachru, S Silverstein, E TI 4D conformal field theories and strings on orbifolds SO PHYSICAL REVIEW LETTERS LA English DT Article AB We propose and test correspondences between 4D quantum field theories (QFTs) with N = 2, 1, 0 (super)conformal invariance and type IIB string theory on various orbifolds of AdS(5) x S-5. This allows us to translate the problem of finding stable nontrivial nonsupersymmetric string backgrounds into the problem of realizing nontrivial renormalization group (RG) fixed point QFTs on branes. RG fixed lines in this context correspond to string theories in which no vacuum energy is generated quantum mechanically. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Univ Calif Santa Barbara, Inst Theoret Phys, Santa Barbara, CA 93106 USA. RP Kachru, S (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NR 19 TC 465 Z9 466 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 1 PY 1998 VL 80 IS 22 BP 4855 EP 4858 DI 10.1103/PhysRevLett.80.4855 PG 4 WC Physics, Multidisciplinary SC Physics GA ZQ908 UT WOS:000073915100006 ER PT J AU Levinton, FM Bell, RE Batha, SH Synakowski, EJ Zarnstorff, MC AF Levinton, FM Bell, RE Batha, SH Synakowski, EJ Zarnstorff, MC TI Radial electric field measurements in reversed shear plasmas SO PHYSICAL REVIEW LETTERS LA English DT Article ID DIII-D TOKAMAK; MAGNETIC SHEAR; IMPROVED CONFINEMENT; POLOIDAL ROTATION; H-MODE; EDGE; TFTR; FLUCTUATIONS; TRANSITION; TURBULENCE AB Measurements of the radial electric field have been obtained on the Tokamak Fusion Test Reactor utilizing the motional Stark effect diagnostic. A large negative excursion in the radial electric field occurs before the transition to the enhanced reversed magnetic shear mode. The electric field is localized to a narrow spatial region and is not observed in discharges without the transition to improved confinement. Concomitant with the radial electric field excursion is a change in the measured impurity poloidal rotation velocity and bursts of magnetic fluctuations. C1 Fus Phys & Technol, Torrance, CA 90503 USA. Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. Sci Res Lab, Somerville, MA 02143 USA. RP Levinton, FM (reprint author), Fus Phys & Technol, Torrance, CA 90503 USA. NR 31 TC 44 Z9 44 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 JUN 1 PY 1998 VL 80 IS 22 BP 4887 EP 4890 DI 10.1103/PhysRevLett.80.4887 PG 4 WC Physics, Multidisciplinary SC Physics GA ZQ908 UT WOS:000073915100014 ER PT J AU Hill, JP Kao, CC Caliebe, WAL Matsubara, M Kotani, A Peng, JL Greene, RL AF Hill, JP Kao, CC Caliebe, WAL Matsubara, M Kotani, A Peng, JL Greene, RL TI Resonant inelastic x-ray scattering in Nd2CuO4 SO PHYSICAL REVIEW LETTERS LA English DT Article ID EMISSION SPECTROSCOPY; ELECTRONIC-STRUCTURE; K-EDGE; LA2CUO4; CUO; SUPERCONDUCTORS; ABSORPTION; SPECTRA; OXIDES AB We report inelastic x-ray scattering studies of charge excitations in insulating Nd2CuO4 as a function of incident photon energy. An excitation of similar to 6 eV is observed when the incident photon energy is tuned through the Cu K edge. This is interpreted as resonantly enhanced inelastic x-ray scattering. Numerical calculations identify the 6 eV feature as a charge-transfer excitation to the antibonding state and suggest that nonlocal effects play a role in determining the shape of the resonance. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. Univ Tokyo, Inst Solid State Phys, Tokyo 106, Japan. Univ Maryland, Ctr Supercond Res, Dept Phys & Astron, College Pk, MD 20742 USA. RP Hill, JP (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RI Hill, John/F-6549-2011 NR 17 TC 134 Z9 135 U1 1 U2 13 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 1 PY 1998 VL 80 IS 22 BP 4967 EP 4970 DI 10.1103/PhysRevLett.80.4967 PG 4 WC Physics, Multidisciplinary SC Physics GA ZQ908 UT WOS:000073915100034 ER PT J AU Moran, MJ Sweider, D AF Moran, MJ Sweider, D TI Measurements of sonoluminescence temporal pulse shape SO PHYSICAL REVIEW LETTERS LA English DT Article ID SINGLE; BUBBLE AB Experiments using time-correlated photon counting and optical bandpass filters measure new features in the time and spectral dependences of single-bubble sonoluminescence (SBSL). The SBSI;full width at half maximum (FWHM) varies with wavelength at 3 degrees C, but not at 24 degrees C. The pulse shapes are dominated by nearly Gaussian peaks with FWHM in the 150- to 300-ps range. At 3 degrees C, increases of pulse width with acoustic drive pressure are independent of wavelength. The pulses have extended tails that decay exponentially, with effective lifetimes of about 150 ps. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Moran, MJ (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 17 TC 44 Z9 45 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 1 PY 1998 VL 80 IS 22 BP 4987 EP 4990 DI 10.1103/PhysRevLett.80.4987 PG 4 WC Physics, Multidisciplinary SC Physics GA ZQ908 UT WOS:000073915100039 ER PT J AU Elphick, C Hagberg, A Meron, E AF Elphick, C Hagberg, A Meron, E TI Phase front instability in periodically forced oscillatory systems SO PHYSICAL REVIEW LETTERS LA English DT Article ID NONEQUILIBRIUM SYSTEMS; DISSIPATIVE SYSTEMS; RESONANCES; BREAKING; DEFECTS; CHAOS AB Multiplicity of phase states within frequency locked bands in periodically forced oscillatory systems may give rise to front structures separating states with different phases. A new front instability is found within bands where omega(forcing)/omega(system) = 2n (n > 1). Stationary fronts shifting the oscillation phase by pi lose stability below a critical forcing strength and decompose into n traveling fronts each shifting the phase by pi/n. The instability designates a transition from stationary two-phase patterns to traveling n-phase patterns. C1 Ctr Fis No Lineal & Sistemas Complejos Santiago, Santiago, Chile. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. Ben Gurion Univ Negev, Jacob Blaustein Inst Desert Res, IL-84990 Sede Boqer, Israel. Ben Gurion Univ Negev, Dept Phys, IL-84990 Sede Boqer, Israel. RP Elphick, C (reprint author), Ctr Fis No Lineal & Sistemas Complejos Santiago, Casilla 17122, Santiago, Chile. RI MERON, EHUD/F-1810-2012 NR 15 TC 53 Z9 53 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 JUN 1 PY 1998 VL 80 IS 22 BP 5007 EP 5010 DI 10.1103/PhysRevLett.80.5007 PG 4 WC Physics, Multidisciplinary SC Physics GA ZQ908 UT WOS:000073915100044 ER PT J AU Alexander, FJ Garcia, AL Alder, BJ AF Alexander, FJ Garcia, AL Alder, BJ TI Cell size dependence of transport coefficients in stochastic particle algorithms SO PHYSICS OF FLUIDS LA English DT Article ID SIMULATION MONTE-CARLO; GAS-FLOWS; DYNAMICS AB Using the Green-Kubo theory, the dependence of the viscosity and thermal conductivity on cell size is obtained explicitly for stochastic particle methods such as direct simulation Monte Carlo (DSMC) and its generalization, the consistent Boltzmann algorithm (CBA). These analytical results confirm empirical observations that significant errors occur when the cell dimensions are larger than a mean free path. (C) 1998 American Institute of Physics. C1 Boston Univ, Ctr Computat Sci, Boston, MA 02215 USA. Lawrence Berkeley Lab, Ctr Computat Sci & Engn, Berkeley, CA 94720 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. San Jose State Univ, Dept Phys, San Jose, CA 95192 USA. RP Alexander, FJ (reprint author), Boston Univ, Ctr Computat Sci, 3 Cummington St, Boston, MA 02215 USA. NR 14 TC 101 Z9 105 U1 0 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD JUN PY 1998 VL 10 IS 6 BP 1540 EP 1542 DI 10.1063/1.869674 PG 3 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 110KB UT WOS:000075379000026 ER PT J AU Cohen, RH Ryutov, DD AF Cohen, RH Ryutov, DD TI Sheath over a rough surface in a tilted magnetic field SO PHYSICS OF PLASMAS LA English DT Letter ID PLASMA AB In this paper a sheath near the wall whose surface is "rough," containing random bumps with a height comparable to the distance between them is considered. The magnetic field is assumed to form a shallow angle with the wall (as in a tokamak divertor) and the scale of nonuniformities is assumed greater than the ion gyroradius. The following new effects caused by surface roughness are identified: (1) The fraction of the surface "wetted'' by the plasma becomes much smaller than for a flat wall. (2) The ion subsheath is broadened and the diamagnetic current in it acquires a complex three-dimensional structure. (3) Cross-held nonuniformities of the plasma potential appear in the bulk plasma. [S1070-664X(98)02006-0] C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Cohen, RH (reprint author), Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 10 TC 9 Z9 9 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD JUN PY 1998 VL 5 IS 6 BP 2194 EP 2196 DI 10.1063/1.872926 PG 3 WC Physics, Fluids & Plasmas SC Physics GA 110KQ UT WOS:000075380300002 ER PT J AU Huba, JD Winske, D AF Huba, JD Winske, D TI Rayleigh-Taylor instability: Comparison of hybrid and nonideal magnetohydrodynamic simulations SO PHYSICS OF PLASMAS LA English DT Article ID MAGNETOTAIL BARIUM RELEASES; EXPANDING PLASMA CLOUDS; LARGE-LARMOR-RADIUS; HALL MAGNETOHYDRODYNAMICS; LIMIT; MODES AB The evolution of the Rayleigh-Taylor instability in a low beta, two-dimensional plasma is studied using a hybrid code and a;nonideal magnetohydrodynamic (MHD) code. The Rayleigh-Taylor instability was chosen as a test case because it is an important mixing process at boundary layers, and because it exhibits different behaviors in the conventional and nonideal limits. The nonideal MHD effects considered are the Hall term and finite Larmor radius (FLR) corrections. Three cases are considered in detail: conventional MHD, weak nonideal effects, and strong nonideal effects. In the conventional MHD regime the usual "bubble and spike" behavior of the Rayleigh-Taylor instability is observed. In the weak nonideal MHD regime long wavelength modes, reminiscent of the Kelvin-Helmholtz instability, dominate nonlinearly but very short wavelength filaments develop at the boundary interface. In the strong nonideal MHD regime, small-scale structures dominate and the boundary layer relaxes via a diffusion-like process rather than a large-scale nonlinear mixing process; In general, the hybrid and fluid simulations are in good agreement. The differences, both physical and numerical, are discussed. (C) 1998 American Institute of Physics. [S1070-664X(98)00906-9] C1 USN, Res Lab, Div Plasma Phys, Washington, DC 20375 USA. Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Los Alamos, NM 87545 USA. RP Huba, JD (reprint author), USN, Res Lab, Div Plasma Phys, Washington, DC 20375 USA. NR 27 TC 22 Z9 22 U1 2 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD JUN PY 1998 VL 5 IS 6 BP 2305 EP 2316 DI 10.1063/1.872904 PG 12 WC Physics, Fluids & Plasmas SC Physics GA 110KQ UT WOS:000075380300016 ER PT J AU Bateman, G Kritz, AH Kinsey, JE Redd, AJ AF Bateman, G Kritz, AH Kinsey, JE Redd, AJ TI Multi-mode transport modeling of the International Thermonuclear Experimental Reactor (ITER) SO PHYSICS OF PLASMAS LA English DT Article ID SIMULATIONS; TOKAMAKS; PLASMA AB Predictions are made for the performance of the International Thermonuclear Experimental Reactor (ITER) [R. Aymar, V. Chuyanov, M. Huguet, R. Parker, and Y. Shimomura, in Proceedings of the Sixteenth International Atomic Energy Agency Fusion Energy Conference, Montreal, Canada 1996 (International Atomic Energy Agency, Vienna, 1997), Paper IAEA-CN-64/01-1] design using the Multi-Mode model in the time-dependent one- and one-half-dimensional (1-1/2-D) BALDUR [C. E. Singer et al., Comput. Phys. Commun. 49, 275 (1988)] transport code. This model predicts the temperature and density profiles observed in present-day tokamak experiments more closely on the average than other models currently available. Simulations using the Multi-Mode transport model, with its inherent gyro-Bohm scaling, indicate that ITER will ignite, even with edge temperatures as low as 0.25 keV (L-mode, or low-confinement mode, boundary conditions) or with volume averaged density as low as 0.775 X 10(20) m(-3) (just below the Greenwald density limit, when T-edge = 0.75 keV). The ignition is found to be thermally stable, and the fusion power production is easily controlled by varying plasma density, impurity content, or edge temperatures. The nonequilibrium impurity radiation model used in these simulations predicts that a significant fraction of the fusion power is radiated when conditions are close to marginal ignition. (C) 1998 American Institute of Physics. [S1070-664X(98)01806-0] C1 Lehigh Univ, Dept Phys, Bethlehem, PA 18015 USA. Oak Ridge Associated Univ, Oak Ridge, TN USA. RP Bateman, G (reprint author), Lehigh Univ, Dept Phys, 16 Mem Dr E, Bethlehem, PA 18015 USA. NR 26 TC 15 Z9 15 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD JUN PY 1998 VL 5 IS 6 BP 2355 EP 2362 DI 10.1063/1.872909 PG 8 WC Physics, Fluids & Plasmas SC Physics GA 110KQ UT WOS:000075380300021 ER PT J AU Deeney, C Nash, TJ Spielman, RB Seaman, JF McGurn, JS Jobe, DO Vargas, MF Gilliland, TL Mock, RC Struve, KW Whitney, KG Pulsifer, PE Apruzese, JP Thornhill, JW Davis, J AF Deeney, C Nash, TJ Spielman, RB Seaman, JF McGurn, JS Jobe, DO Vargas, MF Gilliland, TL Mock, RC Struve, KW Whitney, KG Pulsifer, PE Apruzese, JP Thornhill, JW Davis, J TI Improved large diameter wire array implosions from increased wire array symmetry and on-axis mass participation SO PHYSICS OF PLASMAS LA English DT Article ID Z-PINCH IMPLOSIONS; K-SHELL EMISSION; X-RAY-EMISSION; OPTIMIZATION; PLASMAS AB Aluminum wire array, Z-pinch experiments have been performed on an 8 MA generator using arrays consisting of 24, 30, and 42 wires. These experiments were designed to scan through a region of (array mass, implosion velocity) space in which greater than 30% conversion of the implosion kinetic energy into K-shell x rays was predicted to occur [Thornhill et al., Phys. Plasmas 1, 321 (1994)]. Array masses between 120 and 2050 mu g/cm were used in these experiments. An analysis of the x-ray data taken using 24 wire arrays, shows a one-to-one correspondence between the observed kilo-electron-volt yields (5-64 kJ) and the fraction of initial array mass (0.3%-60%) that is radiating from the K shell. The 30 and 42 wire experiments demonstrated that tighter pinches with increased radiated powers were achieved with these larger wire number, improved symmetry arrays. In addition, increases in the implosion mass and array diameter in the 30 and 42 wire number cases resulted in increases in the radiated yield over the corresponding 24 wire shots, up to 88 kJ, which can be interpreted as due to improved coupling and thermalization of the kinetic energy. Moreover, spectroscopic analyses of the 30 and 42 wire experiments have shown that the increased wire numbers also resulted in K-shell radiating mass fractions of greater than 50%. (C) 1998 American Institute of Physics. [S1070-664X(98)03606-4] C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. USN, Res Lab, Washington, DC 20375 USA. RP Deeney, C (reprint author), Sandia Natl Labs, POB 5800,MS-1194, Albuquerque, NM 87185 USA. NR 22 TC 35 Z9 35 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD JUN PY 1998 VL 5 IS 6 BP 2431 EP 2441 DI 10.1063/1.872919 PG 11 WC Physics, Fluids & Plasmas SC Physics GA 110KQ UT WOS:000075380300031 ER PT J AU Accomando, E Andreazza, A Anlauf, H Ballestrero, A Barklow, T Bartels, J Bartl, A Battaglia, M Beenakker, W Belanger, G Bernreuther, W Biebel, J Binnewies, J Blumlein, J Boos, E Borzumati, F Boudjema, F Brandenburg, A Bussey, PJ Cacciari, M Casalbuoni, R Corsetti, A De Curtis, S Cuypers, F Daskalakis, G Deandrea, A Denner, A Diehl, M Dittmaier, S Djouadi, A Dominici, D Dreiner, H Eberl, H Ellwanger, U Engel, R Flottmann, K Franz, H Gajdosik, T Gatto, R Genten, H Godbole, R Gounaris, G Greco, M Grivaz, JF Guetta, D Haidt, D Harlander, R He, HJ Hollik, W Huitu, K Igo-Kemenes, P Ilyin, V Janot, P Jegerlehner, F Jezabek, M Jim, B Kalinowski, J Kilian, W Kim, BR Kleinwort, T Kniehl, BA Kramer, M Kramer, G Kraml, S Krause, A Krawczyk, M Kryukov, A Kuhn, JH Kyriakis, A Leike, A Lotter, H Maalampi, J Majerotto, W Markou, C Martinez, M Martyn, U Mele, B Miller, DJ Miquel, R Nippe, A Nowak, H Ohl, T Osland, P Overmann, P Pancheri, G Pankov, AA Papadopoulos, CG Paver, N Pietila, A Peter, M Pizzio, M Plehn, T Pohl, M Polansky, N Porod, W Pukhov, A Raidal, M Riemann, S Riemann, T Riesselmann, K Riu, I De Roeck, A Rosiek, J Ruckl, R Schreiber, HJ Schulte, D Settles, R Shanidze, R Shichanin, S Simopoulou, E Sjostrand, T Smith, J Sopczak, A Spiesberger, H Teubner, T Troncon, C Vander Velde, C Vogt, A Vuopion-per, R Wagner, A Ward, J Weber, M Wiik, BH Wilson, GW Zerwas, PM AF Accomando, E Andreazza, A Anlauf, H Ballestrero, A Barklow, T Bartels, J Bartl, A Battaglia, M Beenakker, W Belanger, G Bernreuther, W Biebel, J Binnewies, J Blumlein, J Boos, E Borzumati, F Boudjema, F Brandenburg, A Bussey, PJ Cacciari, M Casalbuoni, R Corsetti, A De Curtis, S Cuypers, F Daskalakis, G Deandrea, A Denner, A Diehl, M Dittmaier, S Djouadi, A Dominici, D Dreiner, H Eberl, H Ellwanger, U Engel, R Flottmann, K Franz, H Gajdosik, T Gatto, R Genten, H Godbole, R Gounaris, G Greco, M Grivaz, JF Guetta, D Haidt, D Harlander, R He, HJ Hollik, W Huitu, K Igo-Kemenes, P Ilyin, V Janot, P Jegerlehner, F Jezabek, M Jim, B Kalinowski, J Kilian, W Kim, BR Kleinwort, T Kniehl, BA Kramer, M Kramer, G Kraml, S Krause, A Krawczyk, M Kryukov, A Kuhn, JH Kyriakis, A Leike, A Lotter, H Maalampi, J Majerotto, W Markou, C Martinez, M Martyn, U Mele, B Miller, DJ Miquel, R Nippe, A Nowak, H Ohl, T Osland, P Overmann, P Pancheri, G Pankov, AA Papadopoulos, CG Paver, N Pietila, A Peter, M Pizzio, M Plehn, T Pohl, M Polansky, N Porod, W Pukhov, A Raidal, M Riemann, S Riemann, T Riesselmann, K Riu, I De Roeck, A Rosiek, J Ruckl, R Schreiber, HJ Schulte, D Settles, R Shanidze, R Shichanin, S Simopoulou, E Sjostrand, T Smith, J Sopczak, A Spiesberger, H Teubner, T Troncon, C Vander Velde, C Vogt, A Vuopion-per, R Wagner, A Ward, J Weber, M Wiik, BH Wilson, GW Zerwas, PM CA ECFA TI Physics with e(+)e(-) linear colliders SO PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS LA English DT Review DE e(+)e(-) linear colliders; top quark; electroweak gauge bosons; Higgs; supersymmetry; compositeness ID HIGGS-BOSON MASSES; PHOTON-PHOTON COLLISIONS; HEAVY-QUARK PRODUCTION; GRAND UNIFIED THEORIES; SUPERSYMMETRIC STANDARD MODELS; SOFTLY BROKEN SUPERSYMMETRY; LOW-ENERGY SUPERSYMMETRY; TO-LEADING ORDER; E+E ANNIHILATION; WEAK INTERACTION AB The physics potential of e(+) e(-) linear colliders is summarized in this report. These machines are planned to operate in the first phase at a center-of-mass energy of 500 GeV, before being scaled up to about 1 TeV. In the second phase of the operation, a final energy of about 2 TeV is expected. The machines will allow us to perform precision tests of the heavy particles in the Standard Model, the top quark and the electroweak bosons. They are ideal facilities for exploring the properties of Higgs particles, in particular in the intermediate mass range. New vector bosons and novel matter particles in extended gauge theories can be searched for and studied thoroughly. The machines provide unique opportunities for the discovery of particles in supersymmetric extensions of the Standard Model, the spectrum of Higgs particles, the supersymmetric partners of the electroweak gauge and Higgs bosons, and of the matter particles. High precision analyses of their properties and interactions will allow for extrapolations to energy scales close to the Planck scale where gravity becomes significant. In alternative scenarios, i.e. compositeness models, novel matter particles and interactions can be discovered and investigated in the energy range above the existing colliders lip to the TeV scale. Whatever scenario is realized in Nature, the discovery potential of e(+) e(-) linear colliders and the high precision with which the properties of particles and their interactions can be analyzed, define an exciting physics program complementary to hadron machines. (C) 1998 Elsevier Science B.V. All rights reserved. C1 DESY, D-22603 Hamburg, Germany. Ist Nazl Fis Nucl, I-10125 Turin, Italy. Univ Turin, Dipartimento Fis Teor, I-10125 Turin, Italy. Univ Milan, Dipartimento Fis, I-20133 Milan, Italy. Ist Nazl Fis Nucl, I-20133 Milan, Italy. Tech Univ Darmstadt, Inst Kernphys, D-64289 Darmstadt, Germany. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Univ Hamburg, Inst Theoret Phys 2, D-22761 Hamburg, Germany. Univ Vienna, Inst Theoret Phys, A-1090 Vienna, Austria. CERN, CH-1211 Geneva 23, Switzerland. Leiden Univ, Lorentz Inst Theoret Phys, NL-2300 RA Leiden, Netherlands. ENSLAPP, F-74941 Annecy Le Vieux, France. Rhein Westfal TH Aachen, Phys Zentrum, D-52074 Aachen, Germany. DESY, Inst Hochenergiephys, D-15738 Zeuthen, Germany. Moscow MV Lomonosov State Univ, Inst Nucl Phys, RU-119899 Moscow, Russia. Weizmann Inst Sci, Dept Particle Phys, IL-76100 Rehovot, Israel. Univ Glasgow, Dept Phys, Glasgow G12 8QQ, Lanark, Scotland. Univ Florence, Dipartimento Fis, I-50125 Florence, Italy. Northeastern Univ, Dept Phys, Boston, MA 02115 USA. Ist Nazl Fis Nucl, I-50125 Florence, Italy. Paul Scherrer Inst, CH-5232 Villigen, Switzerland. NRCPS Demokritos, Inst Nucl Phys, GR-15310 Athens, Greece. CNRS Marseille Luminy, Ctr Phys Theor, F-13288 Marseille 9, France. Univ Cambridge, Dept Appl Math & Theoret Phys, Cambridge CB3 9EW, England. Univ Montpellier 2, Phys Math Lab, F-34095 Montpellier 5, France. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Austrian Acad Sci, Inst Hochenergiephys, A-1050 Vienna, Austria. Univ Paris 11, LAL, F-91405 Orsay, France. Univ Leipzig, Fachbereich Phys, D-04109 Leipzig, Germany. Univ Geneva, Dept Phys Theor, CH-1211 Geneva 4, Switzerland. Indian Inst Sci, Ctr Theoret Studies, Bangalore 560012, Karnataka, India. Aristotle Univ Thessaloniki, Dept Theoret Phys, GR-54006 Thessaloniki, Greece. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Univ Bologna, Dipartimento Fis, I-40126 Bologna, Italy. Univ Karlsruhe, Inst Theoret Phys, D-76128 Karlsruhe, Germany. Univ Helsinki, Helsinki Inst Phys, FIN-00014 Helsinki, Finland. Heidelberg Univ, Inst Phys, D-69120 Heidelberg, Germany. Silesian Univ, Dept Theoret Phys, PL-40007 Katowice, Poland. Swiss Fed Inst Technol, Lab Hochenergiephys, CH-8093 Zurich, Switzerland. Univ Warsaw, Inst Theoret Phys, PL-00681 Warsaw, Poland. Max Planck Inst Phys & Astrophys, Werner Heisenberg Inst Phys, D-80805 Munich, Germany. Ludwig Maximillians Univ, Inst Theoret Phys, D-80333 Munich, Germany. Univ Autonoma Barcelona, E-08193 Barcelona, Spain. Ist Nazl Fis Nucl, Sez Roma 1, I-00185 Rome, Italy. Univ Roma La Sapienza 1, Dipartimento Fis, I-00185 Rome, Italy. UCL, Dept Phys & Astron, London WC1E 6BT, England. Univ Barcelona, Fac Fis, E-08028 Barcelona, Spain. Univ Bergen, Inst Phys, N-5007 Bergen, Norway. Univ Trieste, Dipartimento Fis Teor, I-34014 Trieste, Italy. Turku Univ, Dept Appl Phys, FIN-20500 Turku, Finland. Rutgers State Univ, Dept Phys, Piscataway, NJ 08855 USA. Univ Valencia, Dept Fis Teor, E-46100 Burjassot, Spain. Univ Wurzburg, Inst Theoret Phys, D-97074 Wurzburg, Germany. Lund Univ, Dept Theoret Phys, S-22362 Lund, Sweden. Univ Durham, Dept Phys, Durham DH1 3LE, England. Free Univ Brussels, Serv Phys Particules Elementaires, B-1050 Brussels, Belgium. RP DESY, D-22603 Hamburg, Germany. RI Raidal, Martti/A-6796-2008; Boos, Eduard/D-9748-2012; Kryukov, Alexander/G-8076-2012; Borzumati, Francesca /J-4681-2012; Andreazza, Attilio/E-5642-2011; Raidal, Martti/F-4436-2012; Osland, Per/H-5061-2011; Krawczyk, Maria/B-3184-2012; OI Miquel, Ramon/0000-0002-6610-4836; Osland, Per/0000-0002-6727-5311; Denner, Ansgar/0000-0002-7179-1132; Sjostrand, Torbjorn/0000-0002-7630-8605; Borzumati, Francesca /0000-0001-8204-1145; Andreazza, Attilio/0000-0001-5161-5759; Mele, Barbara/0000-0002-9912-442X; Rosiek, Janusz/0000-0002-1653-1274 NR 289 TC 311 Z9 314 U1 4 U2 23 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-1573 EI 1873-6270 J9 PHYS REP JI Phys. Rep.-Rev. Sec. Phys. Lett. PD JUN PY 1998 VL 299 IS 1 BP 1 EP 78 DI 10.1016/S0370-1573(97)00086-0 PG 78 WC Physics, Multidisciplinary SC Physics GA ZN562 UT WOS:000073658300001 ER PT J AU Kahn, PB Yang, CN Perl, ML Quinn, HR AF Kahn, PB Yang, CN Perl, ML Quinn, HR TI Obituary - Max Dresden SO PHYSICS TODAY LA English DT Biographical-Item C1 SUNY Stony Brook, Stony Brook, NY 11794 USA. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Kahn, PB (reprint author), SUNY Stony Brook, Stony Brook, NY 11794 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD JUN PY 1998 VL 51 IS 6 BP 90 EP 90 DI 10.1063/1.882286 PG 1 WC Physics, Multidisciplinary SC Physics GA ZQ938 UT WOS:000073918100019 ER PT J AU McKay, CP Grunthaner, FJ Lane, AL Herring, M Bartman, RK Ksendzov, A Manning, CM Lamb, JL Williams, RM Ricco, AJ Butler, MA Murray, BC Quinn, RC Zent, AP Klein, HP Levin, GV AF McKay, CP Grunthaner, FJ Lane, AL Herring, M Bartman, RK Ksendzov, A Manning, CM Lamb, JL Williams, RM Ricco, AJ Butler, MA Murray, BC Quinn, RC Zent, AP Klein, HP Levin, GV TI The Mars Oxidant experiment (MOx) for Mars '96 SO PLANETARY AND SPACE SCIENCE LA English DT Article ID VIKING BIOLOGY EXPERIMENTS; LIFE DETECTION EXPERIMENT; MARTIAN SOIL; SURFACE; SEARCH; MODEL; ATMOSPHERE; CHEMISTRY AB The MOx instrument was developed to characterize the reactive nature of the martian soil. The objectives of MOx were: (1) to measure the rate of degradation of organics in the martian environment; (2) to determine if the reactions seen by the Viking biology experiments were caused by a soil oxidant and measure the reactivity of the soil and atmosphere; (3) to monitor the degradation, when exposed to the martian environment, of materials of potential use in future missions; and, finally , (4) to develop technologies and approaches that can be part of future soil analysis instrumentation. The basic approach taken in the MOx instrument was to place a variety of materials composed as thin films in contact with the soil and monitor the physical and chemical changes that result. The optical reflectance of the thin films was the primary sensing-mode. Thin films of organic materials, metals, and semiconductors were prepared. Laboratory simulations demonstrated the response of thin films to active oxidants. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. CALTECH, Pasadena, CA 91125 USA. SETI Inst, Mt View, CA 94043 USA. Biospher Inc, Beltsville, MD 20705 USA. RP McKay, CP (reprint author), NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. EM cmckay@mail.arc.nasa.gov RI Ricco, Antonio/A-5273-2010; OI Ricco, Antonio/0000-0002-2355-4984 FU NIDCR NIH HHS [DE-AC04 94AL85000] NR 35 TC 31 Z9 31 U1 0 U2 8 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD JUN-JUL PY 1998 VL 46 IS 6-7 BP 769 EP 777 DI 10.1016/S0032-0633(98)00011-7 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 107YZ UT WOS:000075239900011 PM 11541819 ER PT J AU Cahoon, EB Shah, S Shanklin, J Browse, J AF Cahoon, EB Shah, S Shanklin, J Browse, J TI A determinant of substrate specificity predicted from the acyl-acyl carrier protein desaturase of developing cat's claw seed SO PLANT PHYSIOLOGY LA English DT Article ID TRANSGENIC TOBACCO; ACID; EXPRESSION; METABOLISM; ENDOSPERM; PLANTS; SITE AB Cat's claw (Doxantha unguis-cati L.) vine accumulates nearly 80% palmitoleic acid (16:1 Delta 9) plus cis-vaccenic acid (18:1 Delta 11) in its seed oil. To characterize the biosynthetic origin of these unusual fatty acids, cDNAs for acyl-acyl carrier protein (acyl-ACP) desaturases were isolated from developing cat's claw seeds. The predominant acyl-ACP desaturase cDNA identified encoded a polypeptide that is closely related to the stearoyl (Delta 9-18:0)-ACP desaturase from castor (Ricinis communis L.) and other species. Upon expression in Escherichia coli, the cat's claw polypeptide functioned as a Delta 9 acyl-ACP desaturase but displayed a distinct substrate specificity for palmitate (16:0)-ACP rather than stearate (18:0)-ACP. Comparison of the predicted amino acid sequence of the cat's claw enzyme with that of the castor Delta 9-18:0-ACP desaturase suggested that a single amino acid substitution (L118W) might account in large part for the differences in substrate specificity between the two desaturases. Consistent with this prediction, conversion of leucine-118 to tryptophan in the mature castor Delta 9-18:0-ACP desaturase resulted in an 80-fold increase in the relative specificity of this enzyme for 16:0-ACP. The alteration in substrate specificity observed in the L118W mutant is in agreement with a crystallographic model of the proposed substrate-binding pocket of the castor Delta 9-18:0-ACP desaturase. C1 Washington State Univ, Inst Biol Chem, Pullman, WA 99164 USA. Brookhaven Natl Lab, Dept Biol, Upton, NY 11976 USA. RP Browse, J (reprint author), Washington State Univ, Inst Biol Chem, POB 646340, Pullman, WA 99164 USA. NR 20 TC 56 Z9 62 U1 1 U2 12 PU AMER SOC PLANT PHYSIOLOGISTS PI ROCKVILLE PA 15501 MONONA DRIVE, ROCKVILLE, MD 20855 USA SN 0032-0889 J9 PLANT PHYSIOL JI Plant Physiol. PD JUN PY 1998 VL 117 IS 2 BP 593 EP 598 DI 10.1104/pp.117.2.593 PG 6 WC Plant Sciences SC Plant Sciences GA ZU295 UT WOS:000074182400026 PM 9625712 ER PT J AU Kramer, GJ Oikawa, T Fujita, T Kamada, Y Kusama, Y Tobita, K Ozeki, T Cheng, CZ Nazikian, R AF Kramer, GJ Oikawa, T Fujita, T Kamada, Y Kusama, Y Tobita, K Ozeki, T Cheng, CZ Nazikian, R TI The determination of the q-profile in the plasma core from Alfven eigenmodes SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Letter ID FUSION TEST REACTOR; TAE MODES; TOKAMAK AB The q-profile has been determined inside the q = 1 surface of ion cyclotron resonance frequency (ICRF) heated plasmas from the observed toroidicity induced Alfven eigenmodes (TAE) that appeared before giant sawtooth crashes. The q-profile deduced from the TAE spectrum is in good agreement with the one obtained from motional Stark effect measurements. C1 Japan Atom Energy Res Inst, Naka Fus Res Estab, Naka, Ibaraki 31101, Japan. Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Kramer, GJ (reprint author), Japan Atom Energy Res Inst, Naka Fus Res Estab, Naka, Ibaraki 31101, Japan. RI Cheng, Chio/K-1005-2014 NR 16 TC 11 Z9 11 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD JUN PY 1998 VL 40 IS 6 BP 863 EP 869 DI 10.1088/0741-3335/40/6/001 PG 7 WC Physics, Fluids & Plasmas SC Physics GA ZY258 UT WOS:000074602100001 ER PT J AU Sips, ACC Baranov, Y Challis, CD Cottrell, GA Eriksson, LG Gormezano, C Gowers, C Greenfield, CM de Haas, JCM von Hellerman, M Huysmans, GTA Howman, A Konig, R Lazarus, EA Luce, T Nielsen, P O'Brien, D Rice, BW Sadler, G Soldner, FX Stamp, MF Strait, EJ Tubbing, BJD Wade, M Ward, DJ AF Sips, ACC Baranov, Y Challis, CD Cottrell, GA Eriksson, LG Gormezano, C Gowers, C Greenfield, CM de Haas, JCM von Hellerman, M Huysmans, GTA Howman, A Konig, R Lazarus, EA Luce, T Nielsen, P O'Brien, D Rice, BW Sadler, G Soldner, FX Stamp, MF Strait, EJ Tubbing, BJD Wade, M Ward, DJ TI Operation at high performance in optimized shear plasmas in JET SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article ID REVERSED MAGNETIC SHEAR; ENHANCED PERFORMANCE; IMPROVED CONFINEMENT; PROFILES; TOKAMAKS AB Heating during the early part of the current rise phase gives a low or negative magnetic shear (= r/q(dq/dr)) in the centre of JET plasmas. Under these conditions the confinement improves with high additional heating power heating during the current ramp-up phase of the discharge. The reduction in the transport manifests itself as a peaking of the profiles with a large gradient region near r/a = 0.55. The best discharges have no transport barrier at the edge of the plasma(l-mode). This allows central power deposition by the neutral beams in JET. A control of the plasma pressure, using feedback of the additional heating power in real-time, minimizes the impact of magnetohydrodynamic instabilities. As a result, these discharges achieve the highest D-D neutron rates in JET; S-n = 5.6 x 10(16) neutrons s(-1), with n(e0) approximate to 6 x 10(19) m(-3), T-e0 approximate to 12 keV and T-i0 approximate to 26 keV. C1 Jet Joint Undertaking, Abingdon OX14 3EA, Oxon, England. Gen Atom Co, San Diego, CA USA. Oak Ridge Natl Lab, Oak Ridge, TN USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. RP Sips, ACC (reprint author), Jet Joint Undertaking, Abingdon OX14 3EA, Oxon, England. NR 26 TC 42 Z9 42 U1 1 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD JUN PY 1998 VL 40 IS 6 BP 1171 EP 1184 DI 10.1088/0741-3335/40/6/020 PG 14 WC Physics, Fluids & Plasmas SC Physics GA ZY258 UT WOS:000074602100020 ER PT J AU Hino, T Prausnitz, JM AF Hino, T Prausnitz, JM TI Molecular thermodynamics for volume-change transitions in temperature-sensitive polymer gels SO POLYMER LA English DT Article DE swelling model; poly(N-isopropylacrylamide); temperature-sensitive gels ID N-ISOPROPYLACRYLAMIDE GELS; GLOBULE TYPE TRANSITIONS; PHASE-TRANSITIONS; LINEAR MACROMOLECULES; IONIC GELS; NETWORKS; SYSTEMS; EQUILIBRIA; COLLAPSE; BEHAVIOR AB A molecular-thermodynamic model is presented to predict volume-change transitions in temperature-sensitive polymer gels. The model uses an extended Flory-Huggins theory as a mixing contribution and a new interpolated affine model suggested by Birshtein as an elastic contribution. The Flory chi parameter is given by the product of a temperature-dependent and a composition-dependent term. Our model also differs from those presented previously because the temperature-dependent term is given by the incompressible lattice-gas model by ten Brinke and Karasz that accounts for specific interactions such as hydrogen bonding. Following conventional practice, the van't Hoff equation is introduced to represent the effect of a small number of ionizable segments in the network chain. Calculated swelling-ratio curves for neutral and weakly ionized aqueous N-isopropylacrylamide gels use molecular parameters obtained from phase-equilibrium data for (non-crosslinked) polymer solutions. In agreement with experiment, the calculated volume-transition temperature of the gel is about 1 degrees C higher than the lower critical solution temperature of the (non-crosslinked) polymer solution. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Prausnitz, JM (reprint author), Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. NR 36 TC 37 Z9 39 U1 0 U2 11 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0032-3861 J9 POLYMER JI Polymer PD JUN PY 1998 VL 39 IS 14 BP 3279 EP 3283 DI 10.1016/S0032-3861(97)10108-2 PG 5 WC Polymer Science SC Polymer Science GA ZP079 UT WOS:000073714400034 ER PT J AU Botti, SA Felder, CE Sussman, JL Silman, I AF Botti, SA Felder, CE Sussman, JL Silman, I TI Electrotactins: a class of adhesion proteins with conserved electrostatic and structural motifs SO PROTEIN ENGINEERING LA English DT Article DE acetylcholinesterase; cell adhesion; electrostatics; nervous system; homology modelling ID DROSOPHILA NEUROTACTIN; CHOLESTEROL ESTERASE; CRYSTAL-STRUCTURE; PERIPHERAL SITE; ACTIVE-SITE; ACETYLCHOLINESTERASE; BINDING; BUTYRYLCHOLINESTERASE; CHOLINESTERASES; ASSOCIATION AB The concept of an electrostatic motif on the surface of biological macromolecules as a definite topographical pattern of electrostatic potentials in three-dimensional space, provides a powerful tool for identification of functionally important regions on the surface of structurally related macromolecules, Using this approach, we identify a functional region common to cholinesterases (ChEs) and to a set of neural cell-adhesion proteins that have been suggested to be structurally related to cholinesterases due to their high sequence similarity, but lacking the key catalytically active serine, Quantitative analysis of the electrostatic surface potential in the area surrounding the entrance to the active site of acetylcholinesterase, and in the analogous zone for the ChE-like domain of the adhesion proteins reveals very good correlation. These findings, examined in the context of previous evidence involving this same region in a possible cell-recognition function for ChEs, leads us to define a class of adhesion proteins which we have named 'electrotactins'. C1 Weizmann Inst Sci, Dept Biol Struct, IL-76100 Rehovot, Israel. Weizmann Inst Sci, Dept Neurobiol, IL-76100 Rehovot, Israel. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Sussman, JL (reprint author), Weizmann Inst Sci, Dept Biol Struct, IL-76100 Rehovot, Israel. OI Sussman, Joel/0000-0003-0306-3878 NR 41 TC 77 Z9 78 U1 0 U2 6 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0269-2139 J9 PROTEIN ENG JI Protein Eng. PD JUN PY 1998 VL 11 IS 6 BP 415 EP 420 DI 10.1093/protein/11.6.415 PG 6 WC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology GA 109CE UT WOS:000075303000002 PM 9725619 ER PT J AU Rajan, SS Lackland, H Stein, S Denhardt, DT AF Rajan, SS Lackland, H Stein, S Denhardt, DT TI Presence of an N-terminal polyhistidine tag facilitates stable expression of an otherwise unstable N-terminal domain of mouse tissue inhibitor of metalloproteinase-1 in Escherichia coli SO PROTEIN EXPRESSION AND PURIFICATION LA English DT Article ID MATRIX METALLOPROTEINASES; INVASION; TIMP-1 AB The active N-terminal domain of the mouse tissue inhibitor of metalloproteinases-1 is a 14.1-kDa polypeptide with three disulfide bonds. When expressed using a T7 system in Escherichia coli, this truncated protein, in contrast to the WT protein, was found only in trace amounts in the cell. However, when the coding sequence was placed downstream of a 60-bp sequence that encoded an in-frame histidine-rich "tag," the fusion product (NF.TIMP*His) was expressed in considerably increased abundance. WT.TIMP-1 was expressed in abundance with or without the tag. The mRNAs encoding the various forms of TIMP were present in similar amounts in all four cases. NF.TIMP*His, renatured and purified on a nickel affinity column, was found to be about 10-fold less effective than native human TIMP-2 at inhibiting cleavage of collagen type I by human fibroblast collagenase. A thrombin cleavage site in the tag was susceptible to cleavage by low levels of a contaminating proteinase. (C) 1998 Academic Press. C1 Rutgers State Univ, Div Life Sci, Nelson Labs, Piscataway, NJ 08854 USA. Ctr Adv Biotechnol & Med, Piscataway, NJ 08854 USA. RP Rajan, SS (reprint author), Argonne Natl Lab, Argonne, IL 60439 USA. FU NCI NIH HHS [CA50183] NR 14 TC 4 Z9 5 U1 0 U2 2 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1046-5928 J9 PROTEIN EXPRES PURIF JI Protein Expr. Purif. PD JUN PY 1998 VL 13 IS 1 BP 67 EP 72 DI 10.1006/prep.1998.0883 PG 6 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology GA ZR858 UT WOS:000074021700011 PM 9631517 ER PT J AU Andersen, B Stevens, RC AF Andersen, B Stevens, RC TI The human D-1A dopamine receptor: Heterologous expression in Saccharomyces cerevisiae and purification of the functional receptor SO PROTEIN EXPRESSION AND PURIFICATION LA English DT Article ID PROTEIN-COUPLED RECEPTORS; I-125 SCH-23982 BINDING; MEMBRANE H+-ATPASE; MOLECULAR-BIOLOGY; YEAST; SOLUBILIZATION; AFFINITY; RAT; ACETYLCHOLINE; PEPTIDE AB Functional human D-1A dopamine receptor has been expressed in Saccharomyces cerevisiae. The primary sequence of the receptor was modified to include two affinity tags at the C-terminus of the protein, a FLAG tag (DYKDDDDK), and a His(6) tag (HHHHHH), These modifications allowed for purification to near homogeneity using immobilized metal affinity chromatography and immunoaffinity chromatography. Radioligand binding demonstrated that the purified and reconstituted receptor binds the antagonist [H-3]SCH23390 with an affinity (K-D = 8.0 +/- 3.2 nM) comparable to that of the native receptor. (C) 1998 Academic Press. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Donner Lab, Div Life Sci, Berkeley, CA 94720 USA. Royal Vet & Agr Univ, Dept Plant Biol, DK-1871 Frederiksberg C, Denmark. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Lawrence Berkeley Lab, Donner Lab, Div Life Sci, Berkeley, CA 94720 USA. RI Stevens, Raymond/K-7272-2015 OI Stevens, Raymond/0000-0002-4522-8725 FU NIGMS NIH HHS [P01 GM51487-01] NR 35 TC 17 Z9 18 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1046-5928 EI 1096-0279 J9 PROTEIN EXPRES PURIF JI Protein Expr. Purif. PD JUN PY 1998 VL 13 IS 1 BP 111 EP 119 DI 10.1006/prep.1998.0862 PG 9 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology GA ZR858 UT WOS:000074021700017 PM 9631523 ER PT J AU Tsuruta, H Vachette, P Kantrowitz, ER AF Tsuruta, H Vachette, P Kantrowitz, ER TI Direct observation of an altered quaternary-structure transition in a mutant aspartate transcarbamoylase SO PROTEINS-STRUCTURE FUNCTION AND GENETICS LA English DT Article DE time-resolved small-angle X-ray scattering; allosterism; domain closure ID X-RAY-SCATTERING; STOPPED-FLOW APPARATUS; DOMAIN CLOSURE; ALLOSTERIC TRANSITION; KINETIC MECHANISM; COOPERATIVITY; INHIBITOR; SUCCINATE; BINDING; MODEL AB Time-resolved small-angle Xray scattering (TR-SAXS) was used to monitor the structural changes that occur upon the binding of the natural substrates to a mutant version of the allosteric enzyme aspartate transcarbamoylase from Escherichia coli, in which the creation of a critical link stabilizing the R state of the enzyme is hindered. Previously, SAXS experiments at equilibrium showed that the structures of the unligated mutant enzyme and the mutant enzyme saturated with a bisubstrate analog are indistinguishable from the T and R state structures, respectively, of the wild-type enzyme (Tauc et al,, Protein Sci, 3:1998-2004, 1994), However, as opposed to the wild-type enzyme, the combination of one substrate, carbamoyl phosphate, and succinate, an analog of aspartate, did not convert the mutant enzyme into the R state. By using TR-SAXS we have been able to study the transient steady-state during catalysis using the natural substrates rather than the nonreactive substrate analogs, The steady-state in the presence of saturating amount of substrates is a mixture of 60% T and 40% R structures, which is further converted entirely to R in the additional presence of ATP, These results provide a structural explanation for the reduced cooperativity observed with the mutant enzyme as well as for the stimulation by ATP at saturating concentrations of substrates. They also illustrate the crucial role played by domain motions and quaternary-structure changes for both the homotropic and heterotropic aspects of allostery. (C) 1998 Wiley-Liss, Inc. C1 Boston Coll, Dept Chem, Merkert Chem Ctr, Chestnut Hill, MA 02167 USA. SLAC, Stanford Synchrotron Radiat Lab, Stanford, CA USA. Univ Paris Sud, MENRT, CEA, CNRS,LURE, Orsay, France. RP Kantrowitz, ER (reprint author), Boston Coll, Dept Chem, Merkert Chem Ctr, Chestnut Hill, MA 02167 USA. FU NIGMS NIH HHS [GM26237] NR 26 TC 14 Z9 14 U1 0 U2 3 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0887-3585 J9 PROTEINS JI Proteins PD JUN 1 PY 1998 VL 31 IS 4 BP 383 EP 390 DI 10.1002/(SICI)1097-0134(19980601)31:4<383::AID-PROT5>3.0.CO;2-J PG 8 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA ZT567 UT WOS:000074100800005 PM 9626698 ER PT J AU Stabin, MG Gelfand, MJ AF Stabin, MG Gelfand, MJ TI Dosimetry of pediatric nuclear medicine procedures SO QUARTERLY JOURNAL OF NUCLEAR MEDICINE LA English DT Article DE child; radionuclide imaging; radiation dosage ID RADIATION-DOSIMETRY; LUNG-DISEASE; COMPLEXES; KINETICS; CHILDREN AB Background. Radiation dose estimates for children of different ages for many different nuclear medicine procedures are presented. Methods. Using standard MIRD methodology, radiation dose calculations were performed for a broad range of radiopharmaceutical agents commonty used in pediatric nuclear medicine. Results from the best available biokinetic models were used in the MIRDOSE 3.1 computer program to obtain dose estimates per unit administered activity for the procedures. Then, assuming typical values of administered activity based on body weight, the dose per procedure for many target organs of interest was calculated and presented in tabular form. The effective dose equivalent (ICRP 30) and effective dose (ICRP 60) are also given. Results and conclusions. The results are presented in multiple tables attached to the text of the article. The information should be quite useful in evaluating radiation doses for many pediatric nuclear medicine procedures, using the best available models and methods. C1 Childrens Hosp, Med Ctr, Dept Radiol, Nucl Med Sect, Cincinnati, OH 45229 USA. Oak Ridge Inst Sci & Technol, Div Med Sci, Radiat Internal Dose Informat Ctr, Oak Ridge, TN USA. RP Gelfand, MJ (reprint author), Childrens Hosp, Med Ctr, Dept Radiol, Nucl Med Sect, 3333 Burnet Ave, Cincinnati, OH 45229 USA. NR 48 TC 44 Z9 44 U1 1 U2 3 PU EDIZIONI MINERVA MEDICA PI TURIN PA CORSO BRAMANTE 83-85 INT JOURNALS DEPT., 10126 TURIN, ITALY SN 1125-0135 J9 Q J NUCL MED JI Q. J. Nucl. Med. PD JUN PY 1998 VL 42 IS 2 BP 93 EP 112 PG 20 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 154NY UT WOS:000077896200002 PM 9695662 ER PT J AU Zeitlin, C Heilbronn, L Miller, J AF Zeitlin, C Heilbronn, L Miller, J TI Detailed characterization of the 1087 MeV/nucleon iron-56 beam used for radiobiology at the alternating gradient synchrotron SO RADIATION RESEARCH LA English DT Article ID 510-MEV/NUCLEON FE-56; FRAGMENTATION; POLYETHYLENE; MODEL AB We report beam characterization and dosimetric measurements made using a Fe-56 beam extracted from the Brookhaven National Laboratory Alternating Gradient Synchrotron (AGS) with a kinetic energy of 1087 MeV/nucleon. The measurements reveal that the depth-dose distribution of this beam differs significantly from that obtained with a 600 MeV/nucleon iron beam used in several earlier radiobiology experiments at the Lawrence Berkeley National Laboratory's BEVALAC. We present detailed measurements of beam parameters relevant for radiobiology, including track- and dose-averaged linear energy transfer (LET), fragment composition and LET spectra measured behind sample holders used in irradiations of biological samples. We also report measurements of fluence behind three depths (1.94, 4.68 and 9.35 g cm(-2)) of polyethylene targets with the 1087 MeV/nucleon beam, and behind 1.94 g cm(-2) of polyethylene with a 610 MeV/nucleon beam delivered by the AGS. These results are compared to earlier measurements with the 600 MeV/nucleon beam at the BEVALAC. (C) 1998 by Radiation Research Society. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Zeitlin, C (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, MS 29-100, Berkeley, CA 94720 USA. RI Heilbronn, Lawrence/J-6998-2013 OI Heilbronn, Lawrence/0000-0002-8226-1057 NR 17 TC 105 Z9 105 U1 0 U2 2 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 USA SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD JUN PY 1998 VL 149 IS 6 BP 560 EP 569 DI 10.2307/3579902 PG 10 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA ZQ060 UT WOS:000073817400004 PM 9611094 ER PT J AU Matsumoto, K Ramsey, MJ Nelson, DO Tucker, JD AF Matsumoto, K Ramsey, MJ Nelson, DO Tucker, JD TI Persistence of radiation-induced translocations in human peripheral blood determined by chromosome painting SO RADIATION RESEARCH LA English DT Article ID IN-SITU HYBRIDIZATION; FLUORESCENCE INSITU HYBRIDIZATION; RAY-INDUCED ABERRATIONS; BODY X-IRRADIATION; INDUCED CELL DEATH; IONIZING-RADIATION; DNA PROBES; GOIANIA BRAZIL; LYMPHOCYTES; MOUSE AB We have investigated the persistence of translocations and other types of chromosome damage with time using human peripheral blood acutely exposed in vitro to Cs-137 gamma rays at doses ranging from 0.5 to 4 Gy, Freshly drawn blood from one donor was irradiated and metaphase chromosomes were prepared 2 to 7 days after exposure. Chromosomes 1, 2 and 4 were painted red-orange and chromosomes 3, 5 and 6 were painted green by fluorescence in situ hybridization (FISH) using "semi-directly" labeled whole-chromosome painting probes. This type of labeling combines direct and indirect labeling and showed significant advantages over both these other methods. All types of structural chromosome aberrations were classified by the Protocol for Aberration Identification and Nomenclature Terminology (PAINT) system. The yields of dicentric chromosomes, acentric fragments and ring chromosomes diminished with time as expected. Translocations exhibited greater persistence but showed a clear and statistically significant reduction in frequency at all doses. The mathematical model suggested that the translocation frequencies would reach a plateau of approximately 4, 15, 51, 106 and 179 translocations per 100 cell equivalents after irradiation with 0.5, 1, 2, 3 and 4 Gy, respectively. When translocations were classified by the conventional system, an analysis of the distribution of translocations and dicentrics per cell indicated that both types of exchanges were Poisson-distributed 48 h postirradiation. However, cells bearing translocations have a higher possibility of having dicentrics than cells without translocations, These findings suggest that dicentrics may contribute to a decline of translocation frequencies with time, and that some translocations are not completely persistent. The results obtained here using human blood exposed in vitro may influence the use of translocations as a retrospective biodosimeter of exposure to ionizing radiation in humans. (C) 1998 by Radiation Research Society. C1 Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94551 USA. RP Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, L-452,POB 808, Livermore, CA 94551 USA. FU NCI NIH HHS [P01 CA59431] NR 44 TC 82 Z9 84 U1 0 U2 0 PU RADIATION RESEARCH SOC PI LAWRENCE PA 810 E TENTH STREET, LAWRENCE, KS 66044 USA SN 0033-7587 EI 1938-5404 J9 RADIAT RES JI Radiat. Res. PD JUN PY 1998 VL 149 IS 6 BP 602 EP 613 DI 10.2307/3579907 PG 12 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA ZQ060 UT WOS:000073817400009 PM 9611099 ER PT J AU Cooper, JA AF Cooper, JA TI Constrained mathematics evaluation in probabilistic logic analysis SO RELIABILITY ENGINEERING & SYSTEM SAFETY LA English DT Article AB A challenging problem in mathematically processing uncertain operands is that constraints inherent in the problem definition can require computations that are difficult to implement. Examples of possible constraints are that the sum of the probabilities of partitioned possible outcomes must be one, and repeated appearances of the same variable must all have the identical value. The latter, called the 'repeated variable problem', will be addressed in this paper in order to show how interval-based probabilistic evaluation of Boolean logic expressions, such as those describing the outcomes of fault trees and event trees, can be facilitated in a way that can be readily implemented in software. We will illustrate techniques that can be used to transform complex constrained problems into trivial problems in most tree logic expressions, and into tractable problems in most other cases. Published by Elsevier Science Limited. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Cooper, JA (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 8 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0951-8320 J9 RELIAB ENG SYST SAFE JI Reliab. Eng. Syst. Saf. PD JUN PY 1998 VL 60 IS 3 BP 199 EP 203 PG 5 WC Engineering, Industrial; Operations Research & Management Science SC Engineering; Operations Research & Management Science GA ZV353 UT WOS:000074296100002 ER PT J AU Mazzucato, E AF Mazzucato, E TI Microwave reflectometry for magnetically confined plasmas SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Review ID DENSITY PROFILE MEASUREMENTS; AMPLITUDE-MODULATION REFLECTOMETRY; ULTRASHORT-PULSE REFLECTOMETRY; PBX-M TOKAMAK; FLUCTUATION MEASUREMENTS; TURBULENT FLUCTUATIONS; DIII-D; ELECTROMAGNETIC-WAVES; RADAR REFLECTOMETRY; FUSION PLASMAS AB This article is about microwave reflectometry-a radar technique for plasma density measurements using the reflection of electromagnetic waves by a plasma cutoff. Both the theoretical foundations of reflectometry and its practical application to the study of magnetically confined plasmas are reviewed in this article. In particular, the role of short-scale density fluctuations is discussed at length, both as a unique diagnostic tool for turbulence studies in thermonuclear plasmas, and for the deleterious effects that fluctuations may have on the measurement of the average plasma density with microwave reflectometry. (C) 1998 American Institute of Physics. [S0034-6748(98)05906-1]. C1 Princeton Univ, Plasma Phys Lab, Princeton, NJ 08543 USA. RP Mazzucato, E (reprint author), Princeton Univ, Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 132 TC 114 Z9 116 U1 3 U2 20 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUN PY 1998 VL 69 IS 6 BP 2201 EP 2217 DI 10.1063/1.1149121 PG 17 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 108RK UT WOS:000075279100001 ER PT J AU Autrey, T Foster, NS Klepzig, K Amonette, JE Daschbach, JL AF Autrey, T Foster, NS Klepzig, K Amonette, JE Daschbach, JL TI A new angle into time-resolved photoacoustic spectroscopy: A layered prism cell increases experimental flexibility SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID ELECTRON-TRANSFER REACTIONS; CALORIMETRY; RADICALS; ENERGY; ENERGETICS; CARBENES; DESIGN; HEATS AB A new pulsed photoacoustic calorimetry cell that uses transmission of light through a pair of dovetail prisms is discussed. The layered prism cell (LPC) combines the enhanced time-resolution capabilities of the "layered" front-face irradiation geometry with the zero-background and broadband flexibility of the classical cuvette geometry. This work provides a phenomenological description of photoinduced pressure changes to yield an analytical expression to calculate the magnitude of the photoinduced acoustic pressure wave in a series of solvents. The mechanical to electrical conversion efficiency for an ultrasonic transducer coupled to the LPC is presented to provide a comparison of the experimentally observed photoinduced acoustic signal amplitudes to the empirically calculated acoustic signal amplitudes. An analysis of the background signals due to absorption and electrostriction of the media provides insight into the issues of sensitivity and limitations of pulsed photoacoustic experiments. The LPC provides several benefits to increase the flexibility of the photoacoustic spectroscopy: (1) greater sensitivity; (2) enhanced time resolution, and (3) the ability to obtain kinetic data in complex solvent mixtures. Under optically dilute conditions in the layered cell geometry, the acoustic transient time, tau a, approaches zero because the photoinduced acoustic wave homogeneously expands against the walls of the photoacoustic cell. To demonstrate the unique capabilities of the LPC, rates of hydrogen abstraction by tert-butoxyl radical from solvent mixtures containing ethyl and methyl alcohol are presented. (C) 1998 American Institute of Physics. [S0034-6748(98)01106-X]. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Autrey, T (reprint author), Pacific NW Natl Lab, POB 999, Richland, WA 99352 USA. EM red@pnl.gov NR 48 TC 24 Z9 24 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUN PY 1998 VL 69 IS 6 BP 2246 EP 2258 DI 10.1063/1.1148928 PG 13 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 108RK UT WOS:000075279100007 ER PT J AU Spear, JD Klunder, GL Russo, RE AF Spear, JD Klunder, GL Russo, RE TI Photothermal deflection spectroscopy of an aqueous sample in a narrow bore quartz capillary SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID ZONE ELECTROPHORESIS; AMINO ACIDS; VIBRATION; PROBE AB An apparatus to perform photothermal deflection spectroscopy on liquid samples within a cylindrical capillary is described. A tunable dye laser, modulated by an optical chopper, serves as an excitation source. The resolution of a spectral absorption peak near 575 nm, of a 1x10(-3) M Nd3+ aqueous solution, demonstrates the effectiveness of the system. The sample is contained within a 75 mu m internal diameter quartz capillary, typical of those used for capillary electrophoresis. Across the middle of the probed section of the capillary, the magnitude of the resolved peak is 5.2x10(-5) absorbance units. A helium-neon laser, focused to a l/e(2) waist diameter of 40 mu m, provides an optical probe beam across the center of the sample, overlapping the excitation beam at an angle of 3 degrees. Maximum signal-to-noise ratio is achieved with the apparatus when the excitation beam is modulated at a frequency near 205 Hz. The deflection responsivity of the probe beam at this frequency is 650 nrad per mu W Of absorbed excitation radiation, with an internal noise level in the system of 0.6 nrad Hz(-1/2). The shot noise from probe beam radiation upon the photodiodes in the position sensitive detector exceeds noise from other sources; [S0034-6748(98)03506-0]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Energy & Environm Technol Div, Berkeley, CA 94720 USA. Univ Calif Lawrence Livermore Natl Lab, Forens Sci Ctr, Livermore, CA 94550 USA. RP Spear, JD (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Energy & Environm Technol Div, M-S 70-193A, Berkeley, CA 94720 USA. NR 28 TC 5 Z9 5 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUN PY 1998 VL 69 IS 6 BP 2259 EP 2267 DI 10.1063/1.1148929 PG 9 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 108RK UT WOS:000075279100008 ER PT J AU Srinivasan-Rao, T Schill, J Ben Zvi, I Woodle, M AF Srinivasan-Rao, T Schill, J Ben Zvi, I Woodle, M TI Sputtered magnesium as a photocathode material for rf injectors SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID PHOTOEMISSION; PERFORMANCE; ULTRAVIOLET; LASER AB In this article, we report the investigation of sputtered magnesium as a suitable photoelectron emitter in a rf injector. The measurements were conducted on a 20 mu m thick Mg layer, ion sputtered on a copper substrate. UV laser induced damage threshold measurements on this sample indicate that laser energy densities of up to 100 mu J/mm(2) at 266 nm, the irradiated surface is indistinguishable from the unirradiated surface. For laser energy densities in the range of 100-300 mu J/mm(2) slight roughening of the surface was evident. At 600 mu J/mm(2), damage is visible, with the depth estimated to be similar to 1 mu m. This damage threshold is six limes larger than that of the bulk magnesium and approaches that of copper. Systematic laser cleaning has improved the quantum efficiency of the surface from 2 X 10(-5) to 2 X 10(-3). This combination of high quantum efficiency and high damage threshold of sputtered magnesium produces a record current density of 25 kA/mm(2) for a metal cathode. The effect of laser cleaning on sputtered Mg, the sample preparation technique for reliable performance. and the parametric dependence of quantum efficiency are reported as well. (C) 1998 American Institute of Physics. [S0034-6748(98)01706-7]. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. RP Srinivasan-Rao, T (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. NR 12 TC 32 Z9 32 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUN PY 1998 VL 69 IS 6 BP 2292 EP 2296 DI 10.1063/1.1148934 PG 5 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 108RK UT WOS:000075279100013 ER PT J AU Alton, GD Meyer, FW Liu, Y Beene, JR Tucker, D AF Alton, GD Meyer, FW Liu, Y Beene, JR Tucker, D TI Enhancing the performances of traditional electron cyclotron resonance ion sources with multiple-discrete-frequency microwave radiation SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB The performances of electron cyclotron resonance (ECR) ion sources, in terms of high-charge-state yields and intensities within a particular charge state, can be enhanced by increasing the physical sizes of the ECR zones in relation to the sizes of their plasma volumes. The creation of a large ECR plasma "volume" permits coupling of more power into the plasma, resulting in the heating of a much larger electron population to higher energies, the effect of which is to produce higher charge-state distributions and higher intensities within a particular charge state than possible in present forms of the ECR source. The ECR plasma "volumes" of traditional B-minimum ECR sources can be increased by injecting broadband microwave radiation (multiple-discrete-frequency, variable frequency, or broad-band-width frequency microwave radiation) derived from standard klystron, gyrotron, or traveling-wave-tube (TWT) technologies (frequency domain). To demonstrate that the frequency domain technique can be used to enhance the performance of a traditional B-minimum ECR ion source, comparative studies were made to assess the relative performances of the Oak Ridge National Laboratory Caprice ECR ion source, in terms of multiply charged ion-beam generation capabilities, when excited with high-power, single-frequency, or multiple-discrete-frequency microwave radiation, derived from standard klystron and/or TWT technologies. These studies demonstrate that the charge-state populations for Arq+ and Xeq+ move toward higher values when excited with two and three discrete-frequency, microwave power compared to those observed when single-frequency microwave power is used. For example, the most probable charge state for Xe is increased by one charge-state unit while the beam intensities for charge states higher than the most probable are increased by factors of similar to 3 compared to those observed for single-frequency plasma excitation. The results of these measurements along with details on the modifications to the injection system required to couple the microwave radiation into the plasma volume of the Caprice source will be presented in this report. (C) 1998 American Institute of Physics. [S0034-6748(98)05306-4]. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Lambda Technol Inc, Raleigh, NC USA. RP Alton, GD (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 10 TC 22 Z9 22 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUN PY 1998 VL 69 IS 6 BP 2305 EP 2312 DI 10.1063/1.1148936 PG 8 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 108RK UT WOS:000075279100015 ER EF